Repair and maintenance of loaders at the enterprise. Forklift Maintenance
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Maintenance and repair of loaders
Maintenance of electrical equipment
Maintenance of the electrical equipment of forklifts, charging points and repair shops is carried out in accordance with the Rules technical operation and safety maintenance of electrical installations industrial enterprises Gosenergonadzor. To control electric forklifts, their maintenance and repairs are allowed to persons who have a certificate of passing the test in knowledge of the rules.
Forklifts powered by fixed mains via a flexible cable must be grounded using a special conductor present in it. Machines of the S-492 type and others moving along rails are grounded through rails connected at the junctions of both threads with metal jumpers welded to them. On loaders with separate electrical devices moving relative to the chassis in the control circuits of command devices, it is preferable to use flexible copper conductors with a cross section of at least 1.5 mm2.
Maintenance, repair, charging of alkaline and acid batteries and the preparation of electrolyte for them are carried out in separate rooms. The presence of batteries of both types in the same room is unacceptable, as it leads to their damage.
Alkaline and acid batteries are charged from motor-generators, semiconductor rectifiers and autodynes. It is advisable that the chargers have an electric contact clock that automatically stops charging after a predetermined time. In this case, after checking the battery, which is switched on for charging, the operating time of the unit and the required charging current are set. In the future, the presence of a worker-charger is not required.
The efficiency in terms of capacity for alkaline batteries is normally 0.55-0.58, for acid batteries - 0.65 - 0.75.
Batteries are charged in rooms with supply and exhaust ventilation.
The content of alkaline traction nickel-iron batteries. Their positive and negative plates are made in the same way and consist of steel perforated lamellas. An active mass is pressed into the cells of the latter: in the positive plates - a mixture of 75% nickel oxide hydrate Ni (OH) 2 and 25% flake graphite, in the negative ones - from powdered electrochemically active highly dispersed iron oxide (FeO and Fe202). The number of negative plates in the accumulator is one more than the number of positive ones. They are arranged alternately, through one and separated by insulating gaskets. Positive and negative plates are assembled on studs with nuts into blocks having leads (borons) from both plates. Blocks of plates are placed with insulation with ebonite gaskets in steel (welded) or plastic cases. Batteries are connected to the battery with plates clamped on the bores with nuts.
Rice. 1. Alkaline batteries for electric forklifts: a and b - 34TNZh-300VM; b and d - 26TNZh-300VM; d - 40TNZh-400; e- 24TNZh-500 and 24TNZh-50SM; w - 35TNZh-950
The amount of electricity supplied to the battery when charging in service should be 1.5 to 1.75 times its rated output (increasing with battery life). Charging is most efficient at a constant current strength for 6-7 hours. It is permissible to charge at a decreasing current strength so that its value at the end of charging is not lower than 60% of normal. Incomplete charging causes a decrease in the output capacity and the number of charge-discharge cycles. The temperature of the electrolyte during charging is not allowed above 43 ° C. If the specified value is exceeded, charging is suspended to cool the batteries. Normal battery life is ensured when discharged to a voltage of at least 1.077 V per battery. Discharging with currents exceeding the normal value reduces the capacity and life of the batteries.
New batteries, received in assembled form, must go through training and control cycles of "charge - discharge". At the end of charging, check the level and density of the electrolyte. In 1-2 hours after the termination of charging, the necks of the batteries and the battery cover are closed.
The electrolyte level and its density are checked before each battery charge in two or three batteries, and after 10 charge-discharge cycles - in all batteries. The electrolyte level should be 15-30 mm above the top edge of the battery plates. If the electrolyte density deviates from the norm, distilled water or an electrolyte of increased density is added, respectively.
The box in which the battery, accumulators, their mouth caps, connecting jumpers and rubber covers are placed must always be kept clean and dry. Dust and salt deposits on the outer parts of the batteries are removed with a clean, damp cloth wrapped around a wooden stick. Rust from the battery case is cleaned with a rag soaked in kerosene, the cleaned area is wiped dry and covered with alkali-resistant bituminous varnish. Vaseline, getting on the varnish coating of the cases, leads to rusting of the battery cases and to the formation of a leak.
When preparing the electrolyte, precautions must be taken, since alkalis and their solutions injure people's skin, corrode shoes and clothes. Therefore, in the process of dissolving alkalis and during the care of batteries, it is required to use goggles, rubber aprons and gloves. If by chance clothes or shoes are doused with alkaline solutions or the latter get on the skin of people, then the wetted areas should be immediately washed with a 3% solution of boric acid or a stream of water until the alkali is completely removed. In case of signs of burns (reddening of the skin, burning), it is necessary to immediately consult a doctor.
Caring for Lead Acid Batteries
The loaders of the Balkankar plant (NRB) are equipped with acid batteries. Forklift and bucket loader starter batteries are also acidic. Acid batteries are delivered together with loaders assembled and charged, in a condition suitable for operation. The electrolyte in acid batteries is an aqueous solution of sulfuric acid.
Used to prepare the electrolyte room temperature distilled water and chemically pure sulfuric acid - density 1.84 according to GOST 667-41.
Sulfuric acid strongly combines with water. Therefore, you should carefully, in a thin stream, pour acid into water, and not vice versa, which is dangerous due to strong splashing. The electrolyte is prepared in glassware, ebonite or lead-lined wooden baths. In this case, protective overalls should be used: rubber aprons, boots and gloves and goggles. In case of contact with acid or electrolyte, hands, face and clothing should be immediately washed with water and sprinkled with drinking (bicarbonate) soda to neutralize.
The dissolution of sulfuric acid in water is accompanied by intense heat generation, which requires control of the temperature of the solution, especially if glassware is used. Take breaks from time to time to allow the pan to heat evenly. The density of the electrolyte is measured with a hydrometer after cooling to a temperature of 30 ° C. The density should be 1.24-1.25 in summer, 1.27-1.28 in winter.
Batteries are filled with electrolyte at a temperature not exceeding 25 °C. To do this, use a rubber pear. After 6 hours, the electrolyte level is checked: it should be 15-20 mm above the safety shield in each battery.
When preparing a new battery for operation, two charge-discharge cycles are performed. The first charge of a battery filled with electrolyte, as well as subsequent charges, is carried out in two stages. The charging mode during preparatory cycles and normal - during battery operation - is indicated in her passport. The temperature of the electrolyte in the batteries before charging should be below 30 °C. All battery caps must be opened. The strength of the charging current in amperes during preparatory cycles for conventional acid batteries should be a value numerically equal to the battery capacity (Ah) at the first stage, multiplied by a factor of 0.06, and at the second stage - 2 times less.
The duration of charging during preparatory cycles at the first stage should be 25-30 hours, at the second - 45-50 hours. The end of the first stage of charging is determined by the voltage of individual batteries, which should reach a value of 2.4-2.45 V. At the end of the second stage charging, the voltage rises to 2.55-2.6 V and remains almost stable for the last two hours.
During charging, the temperature of the electrolyte in the batteries should not exceed 40 °C. If this value is exceeded, charging must be suspended so that the electrolyte temperature drops to 30 ° C, after which charging should be continued.
At the end of charging, the electrolyte density is normally 1.28 + 0.05 and does not change, like the voltage, for the last two hours. If the density of the electrolyte is increased or decreased, it is brought to normal by adding distilled water or acid with a density of 1.4.
An external sign of the end of charging acid batteries is the intensive release of gas, the "boiling" of the electrolyte. The hydrogen released in this case forms an explosive explosive mixture with air, which requires caution. After checking the voltage and density of the electrolyte of all batteries, at least 2 hours after the battery is disconnected from an external current source, the holes in their covers are closed with plugs, the covers are wiped dry (which reduces the self-discharge of the battery) and the terminals are lubricated with petroleum jelly.
The battery is discharged with a current of magnitude numerically equal to the capacity in amperes (Ah), multiplied by a factor of 0.1. Discharging should be completed when the voltage of individual batteries drops to 1.8 V.
The second battery preparation cycle is carried out with the same charge and discharge mode as the first.
The voltage of acid batteries, unlike alkaline batteries, increases gradually during charging to 2.7-2.75 V per cell. Charging acid batteries with relatively small currents for a long time is effective and is recommended after increasing the voltage to 2.4 V per cell.
Normal battery charging during its operation is carried out at a current strength in the first stage, numerically equal in amperes to the battery capacity, multiplied by a factor of 0.14. The strength of the charging current in the second stage should be 2 times less than in the first. The duration of the charge in the first stage is about 5 hours, if the entire capacity is used up.
With shallower discharges, the charging time in the first stage decreases accordingly. The duration of the charge in the second stage is 10 hours. This time can be reduced to 3-5 hours. After 4-5 reduced charges, an equalizing charge is made with the duration of the second stage up to 12 hours. The battery should not be left discharged for more than 2-3 hours. In case of prolonged inactivity of a charged battery, it is necessary to check the voltage on it after 3-5 days and carry out preventive charging every month. In this case, the duration of charging in the first stage can be significantly reduced compared to carrying out normal charging.
Normally operated batteries (i.e., in operation almost daily) are subjected to an equalizing charge once a month in order to bring all batteries to approximately the same capacity. At the same time, the density of the electrolyte in them is also leveled.
Equalizing charging in the first stage does not differ from normal, and in the second stage, 10 hours after its start, the battery is turned off for 1-2 hours. Then charging is continued with a reduced current (its value is indicated in the instruction manual for this type of battery) for 1 h. After that, the battery is turned off again and charging is resumed after 1-2 hours. Such charging continues intermittently until the moment when, after connecting an external current source, intensive gas evolution immediately begins.
In the event of a noticeable decrease in battery capacity, it is necessary to check for sulfation of the battery plates. If sulfation occurs even to a slight extent, it is necessary to subject the battery to 3-5 charge-discharge cycles. The charging current should be 25% normal. After the beginning of the "boiling" of the electrolyte, the current strength is reduced to 15-20% of normal and charging is continued for another 3-5 hours. When the voltage of individual batteries is 2.55-2.6 V and the density of the electrolyte is 1.28 + 0.05 charging is stopped. If sediment is found at the bottom of the vessels, it should be removed and the batteries washed with distilled water.
The causes of sulfation are: systematic incomplete charging, deep discharges to a voltage of less than 1.8 V on separate batteries, leaving the battery discharged for more than one day, electrolyte density exceeds normal, battery operation at temperatures above 30 ° C, charging with currents above normal, prolonged discharge currents of increased strength (the current is considered normal during a 5-hour discharge, at which the voltage of individual batteries drops to 1.8 V), short circuits, exposure of the plates due to a decrease in the electrolyte level.
A sharp drop in battery voltage during discharging, loss of capacity, almost stable values of density and voltage, as well as a significant increase in the temperature of the electrolyte during charging, indicate an internal short circuit.
Reduced voltage when charging and discharging the battery, a noticeable decrease in the output capacity and "boiling" of the electrolyte at a voltage of individual batteries of 2.2-2.3 V may be the result of contamination of the electrolyte with foreign impurities. In these cases, you should discharge the battery to the voltage of individual batteries of 1.75 V, pour out the contaminated electrolyte, rinse the batteries twice with clean water (even better with running water), rinse with distilled water, fill the batteries with newly prepared electrolyte, the density of which should exceed the normal one by 0.025. After that, charge normally.
Care of electric motors, generators and ballasts. For electric forklift engines, the most worn part is the manifold.
The coal-copper dust formed during the operation of the engines fills the gaps between the collector plates, which leads to intense sparking and even to a short circuit between the brushes.
A manifold malfunction is detected by engine heating, especially on the manifold side, and by abnormal noise during operation. Before installing new brushes, their working surface is first processed approximately according to the shape of the collector. After the brushes are installed in place between them and the collector, glass skin No. 00 is laid (abrasive surface to the brushes), and by manually rotating the armature, the final grinding of the brushes is carried out, pressed against the collector only by the brush holder springs. For an approximate determination of the correctness of pressing the brush, a strip of tissue paper is laid between it and the collector and then pulled out. When pressed too hard, the paper is torn and pulled out without force if the pressure is not strong enough.
So that the insulating gaskets do not protrude above the collector, they are “perforated” with the formation of tracks between the plates with a depth of 0.5-1 mm. This work is done on a milling machine with a thin cutter, equal in thickness to the gaskets, or manually with the device shown in fig. 11.2. Then burrs are removed from the collector, cleaned with a hair brush and polished on a machine or manually using a special block with glass sandpaper.
Irregularities or ellipsis of the collector are eliminated by a groove on lathe with a preliminary check of the anchor for runout. Its permissible value is not more than 0.05 mm.
The windings of the stators and armatures are checked for open circuit and short circuit to the case. The insulation resistance of the windings relative to the housing should be at least 300-400 thousand ohms.
Overheating of one of the several excitation windings, accompanied by sparking of the brushes and abnormal heating of the armature, indicates an interturn or short circuit. Faulty coils are identified by low voltage on them and must be replaced. If the armature does not rotate when the starting resistance is turned on, it is necessary to find and eliminate an open in its circuit. When the engine is turned on under load and the armature does not rotate, but after starting off manually it starts to rotate at a high frequency, there is an open in the excitation circuit or burning (contamination) of the contact surfaces on the clamps or in the contactors.
Rice. 2. Device for sawing tracks between collector plates
Rice. 3. Device for grinding the manifold
Rice. 4. Schemes for checking the armature winding: By listening method: a - for open circuit and coil short circuit; b - for a short to the body; 1 - collector; 2 - adjustable contacts; 3 - telephone; 4 - battery; 5 - buzzer; c - voltage drop method; 1 - collector; 2 - additional resistance to the millivoltmeter; 3 - millivoltmeter; 4 - battery; 5 - ammeter; 6 - rheostat; 7 - changeable contacts
An abnormally low frequency of rotation of the armature with intense sparking of the brushes indicates a break in its winding, an interturn short circuit, or desoldering of some of the connections on the collector plates. Checking the armature winding by listening with a handset is shown in fig. 4, a and b and by the voltage drop method - in fig. 4 e. In the second method, a 6-12 V battery is used, which allows a discharge current of 5-10 A, an appropriate rheostat, a millivoltmeter up to 150 mV with additional resistance (about 20 times the resistance of a millivoltmeter). First, the rheostat is fully inserted. In this case, if the armature winding section is working, the millivoltmeter gives the highest reading. After that, the resistance of the rheostat is reduced until the pointer of the millivoltmeter is set to approximately 50-70 mV. During the test, both pairs of plugs are connected in turn to each two adjacent collector plates. The millivoltmeter needle will deviate the most when the winding section is open. With a coil circuit in the section, the arrow of the device gives a smaller deviation. Decrease in armature speed can be the result of shifting brushes c. neutral in the direction of rotation of the armature due to a violation of the fastening of the brush holders. If there is no damage in the excitation circuit and the armature rotates at an increased speed, then the cause is the displacement of the brushes from the neutral against the rotation of the armature.
The collector and brush failures discussed above also occur with DC generators on forklifts and bucket loaders. Lack of excitation may be due to demagnetization of the poles or an open in the armature circuit. The magnetization of the poles is carried out by connecting an external DC source to the excitation windings.
Bearing wear is easily determined by the rolling of the balls (rollers) relative to the cages. Removal of old bearings is made by a puller. Seats on the armature shaft and covers are washed with gasoline and wiped dry. Unpacked new bearings are placed on clean paper and washed with gasoline. The bearings are installed on the shaft with the number facing outward with preliminary heating in an oil bath to 80-100 °C.
When the armature vibrates, it is balanced. The center of mass of the anchor mounted on two horizontal rulers will be located below the axis of rotation. For balancing, you can slightly drill the bottom side of the anchor or fix appropriate weights in the grooves of the upper side, the mass of which is selected. A balanced anchor will not roll over the rulers no matter what position it is turned to.
An anchor that has been rewound or soldered by the “cockerels” of the collector must be checked for balance.
The most common fault with contactors, controllers and relays is contamination or burning of contacts, which is eliminated by appropriate stripping. If the contactors and relays do not work when turned on, then the reason for this may be a winding break or armature (rod) jamming. Abnormal heating of the windings of contactors and relays, accompanied by sparking, most often occurs due to weak contact pressure or wear. In the first case, it is necessary to adjust or change the spring, in the second - to change the contacts. The heating of the windings is also caused by an interturn circuit.
Maintenance of the hydraulic system, brakes and mechanisms of loaders
If the bypass valve malfunctions (detected by failure to lift a load close to the capacity of the loader), check its adjustment. To do this, first drain the oil from the hydraulic system and disconnect the high pressure hose from the hydraulic distributor.
Rice. 11.5. Ball bearing extractor
A tee with a control pressure gauge is screwed onto the released fitting of the hydraulic distributor, the above hose is attached to the free end of the tee. After that, fill the oil tank, start the loader engine and raise the forks to the upper position. In this case, the oil will flow through the bypass valve into the drain pipeline and further into the oil tank, and the pressure gauge will show the pressure of the bypass valve. If it turns out to be 5-10 kg / cm2 lower than the normal one set for the loader of this model, the valve is adjusted to normal pressure, its cap is put in place and sealed (an act is drawn up about this).
If weakened due to permanent deformation or breakage, the bypass valve spring must be replaced. In case of detection of scratches and other wear of the working surface of the valve, it is lapped to the seat. In case of significant wear or breakage, the valve must be replaced. If there are burrs in the seat, then the seat is also replaced. When the movement of the valve is difficult, it should be flushed, the scoring found, reinstall the valve and check if it moves easily. If the total clearance between the spool and the distributor sleeve exceeds<0,04 мм, требуется заменить золотник.
Increased noise during the operation of the pump of the electric loader, as well as a drop in the lifting speed or its involuntary decrease indicate an abnormally small opening of the valve opening. To eliminate this malfunction, it is necessary to adjust the position of the nuts that press the roller of the microswitches so that when the hydraulic distributor handles deviate to the extreme position, the holes for the passage of oil are fully opened.
During operation, it is necessary to monitor the presence of lubrication on the spherical surfaces of the hydraulic booster ball pins and the cleanliness of the rod. If smudges of the working fluid are detected at the joints and through the seals, the corresponding fasteners are tightened. Worn seals are replaced. If there is a break in the discharge hose supplying oil from the pump to the hydraulic booster, it is required to connect the pump discharge port to the drain pipe of the oil tank and close the inlet and outlet of the hydraulic booster, for example, with wooden plugs, in order to protect against contamination. It is necessary to replenish the oil in the hydraulic booster reservoir to the norm. The operation of the forklift truck must be stopped, and it must be returned to the garage for troubleshooting at a low speed at the lowest possible engine speed. If the temperature of the oil in the reservoir rises to approximately 100°C, stop the engine and wait until the temperature drops.
The power steering pump is subject to periodic inspection. For this purpose, a pressure gauge with a valve is inserted between the pump and the discharge hose, blocking the access of the working fluid to the hydraulic booster. The measurement limit of the pressure gauge should be 15-20 kgf / cm2 higher than the normal pressure developed by the pump. First, open the valve and turn the steered wheels of the forklift to the left or right until it stops at low engine speeds. The pressure gauge should show a pressure approximately 5 kgf / cm2 below normal. At a lower pressure, close the valve slowly. The pressure as a result of this should increase by about 5 kg / cm2, which is an indicator of the health of the pump. If the pressure does not increase, then the pump is faulty. When the valve is closed and the pressure, although higher than when the valve is open, but does not reach normal by 5 kg / cm2 or more, there are malfunctions in both the pump and the steering mechanism. This requires a rebuild of both assemblies with the replacement of worn parts, sometimes with the replacement of the pump. During the test, the valve should be kept closed for no longer than 15 s. The wheels can be turned all the way for the same time.
The gaps between the brake shoes and the drum are adjusted to normal with the loader driving wheels slightly raised. In order to adjust the gaps on electric forklifts 02, 04, EPV -1-612 (614), turn the head of the brake shoe cam axle with a wrench until it is pressed against the drum, then turn the specified head 10-15 ° in the opposite direction. After that, the wheel should rotate freely by hand. In the same order, the clearances of other brake pads are adjusted.
To reduce the excessively large free play of the steering wheel, the gaps in the hinges of the longitudinal and transverse rods are eliminated and the gap between the worm and the shaft shaft of the steering arm is reduced. To do this, by rotating the adjusting screw, the bipod shaft with the roller is moved until the minimum required clearance is established. The adjusting screw is locked in this position with a lock nut. When changing the brake fluid or replenishing it, first completely fill the master cylinder, then lower the end of the hose for pumping the brakes into a glass jar (1 liter capacity) half filled with brake fluid. Having unscrewed the air release valve by 7g of a turn, it is necessary to pump out the liquid from the main cylinder, using the pedal available for this. If there is air in the brake system, it is detected by the bubbles that enter the jar from the hose along with the fluid. The ingress of air into the brake system dramatically reduces the effect of the brakes. The cessation of the appearance of bubbles indicates that there is no more air in the system and there is no need for further pumping. It is necessary to ensure that when pumping, the presence of fluid in the main cylinder does not decrease by more than half. Upon completion of the removal of air, the pumping hose is placed in place and the main cylinder is replenished with brake fluid to a level 15-20 mm below the upper edge of the neck. In the absence of air in the brake system and with the normal size of the gaps between the brake shoes and drums, the foot pedal stroke is from 73 to 72 of its possible movement.
To restore the cardan shaft, which has damage to the splined end, the worn part is cut off and the newly made one is welded.
It is recommended to use a screw or hydraulic press with a force of P-5 tons to remove old and fit new bandages with massive rubber tires on the wheel hubs. When performing the above operations, a cylindrical part with a diameter of 3-4 mm less than the outer diameter of the wheel rim, and the height is 10-12 mm more than the width of the tire. Before pressing the old tire and pressing the new one, the locking bolts are removed from the wheel rim. The press force is communicated through a cylindrical ring. Its inner diameter should be 1.5-2 mm larger, and the outer one 1.5-2 mm smaller than that of the bandage.
Rice. 6. Adjustment of gaps between brake pads and drum:
1 - the head of the axis of the brake shoe cam; 2 - driving axle
After removing the old bandage, the seating surface of the hub is washed, the burrs and other irregularities found are cleaned, and lightly lubricated with machine oil. A new tire is heated to a temperature of 50-60 ° C in a water bath, after which it is installed on the wheel hub. At the end of pressing in the bandages through the holes in the wheel rims for the lock bolts, sockets are drilled, threads are cut into them, after which the lock bolts are screwed into place. Parts of the undercarriage of tracked loaders are restored by surfacing and subsequent machining on appropriate machines. In some cases, cylindrical parts are pressed on, which are, as it were, part of the working surface of idler wheels and caterpillar rollers, with their welding around the perimeter on both sides.
Rice. 7. Removing bandages with worn massive tires
To bring the pitch of the caterpillar tracks to the norm in case of its increase by 3% or more, the pins and bushings of the tracks with one-sided wear are rotated 180 ° and pressed in again. The holes developed in operation in the tracks are scalded and bored to landscape dimensions. Newly assembled after the restoration of worn parts, the track belts should not have curved edges. It is necessary to ensure the ease of rotation of the tracked rollers. They should be in a straight line. The transverse displacement of the roller shoulders is permissible no more than 2.5 mm. The movement of rollers along the axis from one extreme position to another is allowed 0-2 mm.
With a lot of wear, the teeth of the buckets are first welded with conventional electrodes and then with stalinite. To restore worn leading edges, a strip of steel sheet 25-30 mm thick is welded, the outer edge of which is pre-cut at an angle of about 30 ° and welded with stalinite.
The deformed parts subjected to editing are heated to a temperature of 800-850 ° C (light red heat).
When cooling to 700 ° C (dark red heat), the dressing must be suspended and reheated, and then continue dressing until the desired shape is obtained.
Organization of maintenance and repair of loaders
The maintenance of loaders, their supervision and their repair are regulated in railway, sea and river transport by the relevant departmental documents (Instructions for the operation of loading and unloading machines No. TsM / 2636, approved by the Ministry of Railways of the USSR on July 21, 1969, Regulations on the preventive maintenance of reloading machines of seaports of the Ministry of the Navy of the USSR, etc.), and at factories and other enterprises - documents developed taking into account the specifics of specific working conditions and the existing production base for repairs.
Forklifts may be operated by persons 18 years of age or older who have certain qualifications, medical examinations and an annual knowledge test, including the operating instructions for this machine and safety regulations, and, if necessary, the rules of the road. Car, tractor and pneumatic wheel loaders are assigned by the administration to certain drivers. Electric forklifts can be serviced by integrated crews. The workers included in them must have the right to operate electric forklifts. Carrying out loading and unloading operations with the use of loaders is based on the technology installed at the railway station (in the port) or at the enterprise. At the same time, local conditions in warehouses and operating modes of forklifts must comply with the instructions for use for specific types of machines.
Forklifts, except for those used indoors, as well as tractor loaders between shifts, as a rule, are located in open parking areas, preferably covered with cement concrete slabs. These sites provide maintenance services for forklift trucks. To carry out certain types of work on TO-1 and TO-2 and current repairs, closed garages with inspection ditches are required to check the machines from below and perform certain types of repair work, and a beam crane or other mechanism with a lifting capacity of 1-2 tons. Garage doors should be at least 3.5 and 3 m high and wide, respectively.
Garages are provided with water or steam heating. Illumination at floor level should be 25-40 lux. It is desirable to use fluorescent lamps as the most economical and hygienic.
On the inspection ditches, low-voltage portable electric lamps (12V) are used. Garages must be equipped with water supply, sewerage and exhaust ventilation. Approximate internal dimensions of the garage for one forklift with a carrying capacity of 3-5 tons: width 6-7 m, length 8-10 m, height along the walls 5-5.5 m.
Rice. 8. Garage for 12 electric forklifts with charging station:
1 - tanks for water and electrolyte; 2 - manual water pump; 3 - distiller; 4 - bath for electrolyte preparation; 5 - fume hood; 6 - a cabinet of spare parts; 7 - desktop drilling machine; 8 - locksmith's workbench; 9 - wall swivel crane; 10 - wardrobe; 11 - stands for rechargeable batteries; 12 - beam crane; 13 - distribution cabinet; 14 - charging units; 15 - grinding machine
At garages it is necessary to have workshops. Their equipment should include: universal drilling, grinding and screw-cutting lathes, a workbench with a vise, an electric welding unit, a set of metalworking tools. The building of the workshops should contain premises: for caring for batteries, storing tools, spare parts and materials, a wardrobe, a sanitary unit, a room for eating.
Garages with charging points are being built for maintenance and current repairs of electric forklifts and charging batteries. They are usually adjacent to or close to warehouse buildings where electric forklifts operate. Garage and charger are located adjacent in the same building. Sometimes they have separate doors. The building is built from fire-resistant materials, the walls are painted (depending on the type of batteries used on the loaders) with alkali-resistant or acid-resistant paint, the floors are made with a concrete base and asphalt coating.
Charging points should consist of three isolated compartments: electrolyte, aggregate and charging (Fig. 8).
The electrolyte room is equipped with an exhaust chemical cabinet, water supply and drainage to the sewer. It contains a distiller, an electrolyte preparation bath, a washbasin, tanks or bottles for ready-made electrolyte and distilled water, a cabinet for storing solid alkali (or battery sulfuric acid) in hermetically closed vessels, as well as for inventory and protective clothing (hydrometers and thermometers for measurements of the density and temperature of the electrolyte, containers and measuring vessels for the preparation and pouring of the electrolyte, rubber bulbs, scales, rubber gloves, apron, boots and goggles).
The first aid kit should contain a vessel with a solution of soda or boric acid when servicing alkaline batteries.
In the aggregate compartment, converters from alternating current to direct current or semiconductor charging units, a switchboard are installed, and the following are stored to control the correct charging of batteries: a portable DC voltmeter, a load plug, a portable lamp (low voltage).
The repair department is equipped with an inspection canvas for checking and maintaining the undercarriage of the loaders. The dimensions of the ditch for one electric loader are: length 2.5 m, width 0.6 and depth 1.5-2 m. The ditch is equipped with a ladder at one end, its walls and bottom are concreted.
For the repair of loaders, filling them with fuel, working fluid of hydraulic systems, lubricating oils and brake fluid, mechanized distances for loading and unloading operations on railways, ports and industrial enterprises must have warehouses for replaceable units and assemblies, spare parts and repair materials and storerooms for storage fuels and lubricants.
The operability and serviceability of loaders during the service life established for them is ensured by the implementation.
Rice. 9. Placement of the tracked loader TO-7A on the railway platform
a - layout: 1 - spare parts box; 2 - persistent bars; 3 - wooden stops; 4 - stretch marks; 5 - special nails Ts.T - center of gravity of the platform;, b - section of thrust bars; h - not less than 75 mm, in - not less than 150 mm
All types of maintenance and current repair of loaders are carried out in accordance with the requirements of operational documentation.
Maintenance and repair of machines are carried out in a planned manner.
Maintenance and repair planning. Organizations that have single-bucket loaders on their balance sheet develop annual plans for the maintenance and repair of machines, as well as monthly schedules for the maintenance and repair of machines (Tables 16 and 17). The order of delivery for repair and issue from repair of machines is regulated by the following standards: GOST 24406-80, GOST 24407-80 and GOST 24408-80.
The following maintenance and repair activities are planned: shift maintenance (EO); scheduled maintenance (TO-1, TO-2, TO-3); seasonal service (SO); current repairs (T) and major repairs (K).
When planning maintenance, provide for the maximum use of non-working machine time for these activities.
The annual plan for maintenance, T and K is developed on the basis of the planned number of hours of operation of the machine per year, data on the number of hours worked by machines at the beginning of the year from the start of operation or after K, and regulatory data on the number, frequency and labor intensity of MOT, T and K. The annual plan is determined by the number of scheduled maintenance and repairs for each machine and is the basis for calculating the need for material and labor resources when developing production plans.
A monthly schedule of maintenance, T and K is compiled for each machine based on data on the number of hours worked by the machine at the beginning of the planned month, as well as on the basis of standard data on the number, frequency and labor intensity of maintenance, T and K.
The monthly schedule is linked to the construction schedules. The terms of maintenance and repair of machines, established by the monthly schedule, in exceptional cases can be changed in agreement with the enterprise at whose facilities they are used.
Maintenance and current repair of tires must be carried out in accordance with the requirements contained in the "Technical description and operating instructions" of the manufacturer.
Maintenance and repairs of loaders must be carried out in strict accordance with the deadlines established by the monthly maintenance and repair schedule agreed with the organizations using the machines, no later than 3 days before the start of the planned month.
Regular and scheduled maintenance. SW machines are carried out before the start and at the end of the work shift, as well as during breaks in the operation of the machine that arise for organizational reasons (lack of work front, materials, transport, etc.). The following requirements apply to the EO:
- cleaning and washing operations are performed first of all in order to ensure the necessary preparation of the machine for subsequent operations;
- during control operations, disassembly of units and assembly units is not allowed;
— refueling of the machine is carried out only in a closed way, with clean filtered oil, settled and filtered fuel. Before refueling, it is necessary to thoroughly clean the necks and plugs of the fuel tanks.
TO is subject to the following requirements:
- diagnostics of the technical condition of the machine must precede adjustment and minor repair operations;
- adjustment operations must ensure the normal interaction of units, assembly units and machine parts; fastening operations must ensure the fastening of the components of the machine, provided by the manufacturer; it is forbidden to replace the type of fastening provided by the manufacturer with any other type of fastening (for example, bolted or welded connection);
- lubrication operations are performed in accordance with the instructions of the operational documentation of the machine manufacturers;
- minor repair operations should ensure the elimination of minor faults found during the inspection and diagnostics of the technical condition of the machine.
A downtime of a machine in maintenance is taken into account in calendar days from the date the machine was stopped in maintenance until the date it was put into operation.
Information about the completion of maintenance is recorded in the maintenance log, and then transferred to the form or passport of the machine within a month.
Seasonal maintenance (SS) is performed 2 times a year when preparing the machine for use during the next season (summer and winter).
In addition to the requirements for maintenance, the following requirements are imposed on the technological process of current repair (T):
The current repair technology should not exclude the possibility of subsequent repairs; it should not lead to a deterioration in the performance of the machine, a decrease in its strength, a violation of the interchangeability of components and parts;
The downtime of the machine in T is taken into account from the date it was put into repair until the date it was put into operation. Calculate idle time in calendar days.
Information about the implementation of T is registered in the passport or form no later than one month from the date of its implementation.
Information about changes in the design of the machine or in its components and about replacing them at T is recorded in the passport or form.
Overhaul (K). The need for major repairs is determined by inspecting the machine by a commission headed by the chief engineer (chief mechanic) of the organization.
Inspection of the machine is carried out after the number of hours it has worked, equal to the value of the overhaul cycle.
If the machine, due to its technical condition, does not need major repairs, then the commission sets a new deadline for its implementation, allowing further operation of the machine. The results of the commission's work are documented. Overhaul is carried out at repair plants, at the bases of operation it is carried out only by the aggregate-nodal method.
The procedure for the delivery of machines, as well as their acceptance from overhaul, is established by the "Rules for the delivery for repair and acceptance from repair of machines, assemblies and assemblies in construction", approved by the USSR State Construction Committee.
The driver and the district mechanic must immediately notify the chief mechanic (chief engineer) of the need for unscheduled repairs.
To carry out an unscheduled repair, the local mechanic, with the participation of the crew of the vehicle, draws up an act in which he indicates the composition and reasons for the unscheduled repair, the damage caused to the construction industry, and the cost of the unscheduled repair.
Information about the implementation of unscheduled repairs is recorded in the repair log book, from where they are transferred to the passport or form for the car no later than a month.
Organizations - owners of machines must provide a full range of activities for the maintenance system and
by the forces of their own bases (repair plants, master-reM ° N rophylactories, mobile technical maintenance vehicles, repair of construction machines, etc.) and at the enterprises of “” ^ one organizations on the basis of contractual relations. accounting and control of maintenance and repair of machines, lowerizations, on the balance of which the machines are located, are also required to systematically record their operating time and measures taken for maintenance and repair in the amount provided by the forms (passports) of machines, composition and composition -° neighing which are regulated by OST 22-10-75.
The running time of machines equipped with meters is determined by their readings, the running time of machines without meters is determined by the data of shift time accounting, adjusted using the intra-shift utilization factor.
The coefficient of intra-shift use is determined by chronometric observations, or by a special method.
Refueling and lubrication of loaders. When operating forklifts, use only those types of oil, grease and fuel that are recommended by the instruction manual. Other types of fuels and lubricants must not be used.
The reliability and durability of machines largely depend on the timely and high-quality lubrication of assembly units. With timely lubrication, wear of parts is significantly reduced. Lubrication of loaders is usually combined with the next maintenance.
Liquid lubricants are poured into the crankcases and oil tanks of the hydraulic system. The oil level in the crankcases should be periodically monitored along the lower edge of the control or oil filling hole, and in the boxes - according to the marks of the oil indicator rod.
Liquid lubricants should be replaced immediately after the machine is stopped, when the units are warmed up, it is first necessary to flush the crankcases of assembly units and hydraulic systems within the time periods specified in the periodic maintenance and lubrication maps.
Greases are used to lubricate assembly units and parts of loaders with a syringe or manually fill the lubricant during assembly. Before lubrication, dirt is carefully removed from grease fittings, plugs, etc. to prevent it from getting into the mechanisms.
Lubricants are pressed with a lever-plunger syringe until the lubricant appears from the joints of the parts of the lubricated assembly unit.
The syringe should be periodically disassembled and thoroughly washed in kerosene or diesel fuel. It is also recommended to do this before filling the syringe with a different grade of lubricant.
Lubrication of loaders should be carried out in accordance with the lubrication charts. When lubricating engines, it is necessary to follow the instructions for the operation of engines, and the running systems and other assembly units of basic tractors and tractors - the instructions for operating tractors and tractors.
Maintenance, repair and operation of loaders. Basic provisions MAINTENANCE AND REPAIR OF THE ELECTRIC LOADER. 1. The driver is responsible for the correct maintenance of the electric forklift, while he must: 1.1. Keep machinery and equipment clean and in good working order. 1.2. Timely lubricate all mechanisms of the forklift truck in accordance with the manufacturer's instructions. 1.3. Lubricants and cleaning materials should be stored in a closed metal container, used cleaning material should be removed from the forklift. 1.4. Know the timing of the maintenance (TO) of the electric forklift and make scheduled preventive repairs on time. The results of maintenance should be recorded in the logbook with a record of the time, place and amount of work. 2. The electric forklift is taken out for maintenance or overhaul by order of the immediate supervisor (mechanic) of the driver, about which an appropriate entry must be made in the logbook. 3. It is forbidden to use an electric forklift taken out for repair to perform any work on lifting and moving loads. 4. All repairs must be carried out with the engine off. If for adjustment it is necessary to make any movements by parts of the electric forklift, the driver can turn on the levers only on the signals of the person directly involved in the adjustment of the electric forklift. Forklift maintenance and overhaul. Repair of steering axles (restoration of steering axle beams) Production of chrome-plated rods for hydraulics Overhaul of engines (run-in at the stand) Development and manufacture of power electronics for electric forklifts Complete replacement of power electrical equipment on electric forklifts Overhaul of automatic transmissions of forklifts Overhaul of mechanical transmissions of forklifts loaders Restoration of lifting devices Repair and maintenance of traction motors Repair of hydraulic cylinders and hydraulic components Repair of drive axles of loaders consequently, increases the safety of forklifts. Prevention will avoid serious breakdowns and the need to purchase or rent additional equipment. Repair of lifting equipment, loaders, skid steer loaders, electric loaders, diesel and petrol loaders. The maintenance and repair of the loader, depending on the urgent need, may include: Repair of the electrical equipment of the loader Repair of the ignition and power supply system of the loader Adjustment and repair of the electronic unit for the electric loader Repair and adjustment of the hydraulic cylinders of the loaders Adjustment of the operation of the loader mast. Repair of the loader control. Repair of the running gear loader. Repair of the fuel system. Overhaul of the loader. Repair work can take place both comprehensively and locally, for specific types of service. Maintenance is carried out by professionals using high-precision, modern measuring equipment. 6. Power supply devices for industrial transport At present, in all industries, more and more attention is paid to the mechanization of production cycles, there is a tendency to replace manual labor with technical means as much as possible. This fully applies to warehouse complexes, where a number of operations that are physically difficult for a person - moving, lifting and lowering loads - are performed by equipment with an electric drive. The well-organized system of technological processes here is largely determined by the reliability of the operation of industrial vehicles - loaders, stackers, trolleys, automatic vehicles, robocars, lifts and other equipment. The environmental and economic advantages of electric transport over other types of motorized vehicles are obvious, which contributes to its wide distribution. The main source of power supply for electric motors of vehicles in warehouses for various purposes are traction batteries (batteries). They are also widely used as power sources for scrubbing and sweeping machines, mine electric locomotives, public transport, household appliances - wheelchairs, boats, etc. Traction batteries are easy to install and connect, they are simple and reliable in operation and storage. Maintenance of batteries During daily maintenance: clean the battery from dust and dirt; wipe with a rag soaked in ammonia. Check the fastening and tightness of the contacts of the wire tips with the battery pins. Rice. 6. Checking the condition of the battery: a - determining the density of the electrolyte with an acid meter; 6 - measurement of voltage with a load plug Check the reliability of the battery fastening. During the first maintenance No. 1 (TO-1), carefully inspect the battery; clean and wipe; disconnect the wire ends from the battery; clean the battery terminals and wire lugs and fasten tightly; fix the battery in its socket; clean the ventilation holes in the traffic jams; check the electrolyte level and top up with distilled water if necessary. During maintenance No. 2 (TO-2), maintenance work No. 1 is performed and, in addition, the state of charge and the performance of the batteries are checked. The degree of charge is checked by measuring the density of the electrolyte with an acid meter or the voltage at the battery terminals with a load plug (Fig. 6). A decrease in electrolyte density by 0.01 indicates that the battery has been discharged by about 6%. If the battery or any of the batteries is discharged by 25% in winter and 50% in summer, then such a battery must be charged. The design of lead-acid batteries A traction lead-acid battery is a rigid metal structure (box-container) with an anti-corrosion, most often plastic coating, inside which there are 2 V battery cells. The number of cells of a traction battery determines its voltage (4, 6, 12, 24, 40 , 48, 72 and 80 V), and the type of elements is capacity (from 110 to 1550 Ah). Classical lead batteries of the PzS type with positive plates made of lead-antimony alloy (shell type) and negative plates made of pure lead (plain type) have found wide application. Traction battery device: 1, 5 - negative plates; 2, 4 – microporous separator; 3 - positive armored plate; 6, 7 - blocks of plates with a pole jumper and a bolted pole; 8 - plug; 9 - block of plates; 10 - prism; 11, 12 - body and cover of the element; 13 - pole seal; 14 – flexible interelement connection; 15 - protective cap; 16 - pole bolt; 17 - plugs for centralized topping up of water with level control; 18 - hose wire of the topping system; 19 - battery case All traction batteries for electric vehicles can be divided into serviced, low-maintenance and maintenance-free. To charge the batteries of the first two types, a special charging room with supply and exhaust ventilation is required. Maintenance-free batteries are relatively new, but they are very promising because the charging process is safe and does not require a separate room. Unfortunately, domestic manufacturers do not produce such batteries yet. Many improvements have been introduced in modern traction batteries, which have made it possible to increase their capacity and provide higher electrical and operational characteristics, and reduce maintenance time to a minimum. Thus, a number of models from leading manufacturers can be equipped with an electrolyte mixing system. It is needed for the optimal use of the active mass, which is achieved due to the uniform distribution of the electrolyte density over the height of the plates by mixing. Mixing is carried out using a system of tubes built into the battery, through which air is supplied using a membrane pump. It is recommended to use the system to increase capacity, reduce charging time and prevent overheating of the battery during charging. Using it, you can make intermediate charges to restore capacity and prepare the battery for further operation during breaks in the transport. As an option, many battery manufacturers offer a centralized water top-up system, including an automated one, with a controlled magnetic valve. On electric forklift batteries Special cell plugs allow you to add water to the usually placed under the optimum level and measure the density of the electrolyte. For the driver's seat and serve as an automatic exchange of data on the parameters of the battery, the level of electrolyte balance, temperature and state of charge between the battery and the charger is a special controller. With it, the charger automatically selects the charging profile and sets the optimal charging mode. Systems of scheduled preventive maintenance and repair of machines The system of scheduled preventive maintenance and repair of machines is a set of organizational and technical measures carried out in a planned manner to ensure the operability and serviceability of machines throughout their entire service life, subject to specified conditions and operating modes . The planned nature of the system allows you to determine in advance the need for materials, spare parts, equipment and staff of workers necessary for maintenance and repair. The system is called preventive, since the mandatory maintenance and repair are aimed at preventing machine malfunctions, as well as the causes of their occurrence. Maintenance (TO) is a set of operations to maintain the operability or serviceability of the machine when it is used for its intended purpose, stored and transported. The maintenance of loaders according to the frequency and scope of work is divided into the following types: shift maintenance (EO), scheduled maintenance (TO), seasonal maintenance (SO). Maintenance intervals are indicated in the operating instructions. Every shift maintenance is performed between shifts (before or after the end of the work shift) to ensure uninterrupted operation during the shift. Every shift service includes the following works: external care (washing and cleaning of the car); checking the technical condition and readiness of the machine for operation (checking the fastening of the main assembly units, refueling and cooling liquid); lubrication in accordance with the instructions; testing the operation of the machine. Identified malfunctions during EO must be eliminated. Scheduled maintenance is designed to reduce the wear rate of the mating machine parts through the planned implementation of technological measures. Periodic maintenance includes work on daily maintenance, as well as diagnostic, fixing, adjustment and lubrication work. Seasonal maintenance is carried out twice a year to prepare the machine for winter or summer operation. Maintenance is usually done with the tool kit that comes with every new machine. Repair is a complex of operations to restore the serviceability or operability of the machine and restore the resource of the machine or its component. The resource of a machine is its operating time from the beginning of operation to the limit state, i.e. a condition in which further use of the machine for its intended purpose is unacceptable or impractical. Repair is carried out to eliminate malfunctions that occur during the operation of the machine, as well as those detected in a planned manner. Repair includes cleaning and washing the machine, dismantling, compiling a list of defects, replacing worn or damaged parts and assembly units with new or repaired ones, assembly, bench and running tests of assembly units and the entire machine, painting. Repair work also includes operations to restore parts - welding, coating, metalwork and machine work. The amount of repair work depends on the technical condition of the machine and the number of operating hours in operation. Two types of scheduled repairs are carried out: current and capital. Current repairs are performed to ensure or restore the machine's operability by replacing or restoring individual assembly units and parts. Scheduled maintenance should ensure the guaranteed performance of the machine until the next scheduled maintenance. During current repairs, machines disassemble only component parts requiring repair, eliminate malfunctions and replace individual assembly units and parts with new or pre-repaired parts Partially disassemble the engine with systems for replacing wear parts, cleaning from carbon deposits and scale, adjust fuel equipment, hydraulic drive and electrical equipment, adjust elements power transmission, replace the clutch discs. If necessary, the details of the metal structure, cabins and hoods are corrected and welded. Overhaul is performed to restore the full resource of the machine with the replacement or restoration of any of its components, including the base ones. During a major overhaul, the machine is completely dismantled, all mechanisms are restored in accordance with the technical specifications for repairs, worn parts are replaced with new or pre-repaired parts. After assembly, individual assembly units are subjected to bench tests, and the entire machine to acceptance tests. It is advisable to carry out current and major repairs by the aggregate method, in which faulty units are replaced with new or pre-repaired units. The advantage of the aggregate method is that it is possible to quickly repair machines both in operating conditions and at repair plants. Current repairs are carried out at the place of operation of the machine or at repair and maintenance bases; capital, as a rule, - at specialized repair plants. Means of maintenance and repair. Each operating organization must have a repair and maintenance base that allows performing maintenance and repair work. Scheduled maintenance of machines is carried out, as a rule, during off-shift hours. Every shift maintenance is carried out by the driver of the loader. Scheduled maintenance (including refueling of vehicles) and repairs are carried out centrally by specialized teams (links) of sites for scheduled preventive maintenance and repair of the base. For machines that return to base at the end of the shift, maintenance is carried out by crews in centralized workshops. For cars remaining after a shift at the place of work, mobile teams are organized. For maintenance, as well as current repairs at the place of work, mobile workshops on a chassis are used, equipped with the necessary set of tools, fixtures and spare parts. Maintenance workshops are equipped with tanks for fuel, water, lubricants, a pump for external washing of machines and a compressor. In the workshops there are locksmith vices, compartments for tools, appliances and fixtures, spare parts. Workshops for carrying out current repairs are equipped with an alternating current generator, a crane, a winch, a welding unit, and a hydraulic press. Repair and maintenance bases are also equipped with fuel and oil tankers. Maintenance and repair planning. Forklift operators must develop annual plans and monthly maintenance and repair schedules. According to the annual plan, the number of maintenance and repairs for each machine is determined, the need for spare parts and labor resources is calculated. Based on the data on the overhaul, a request for repairs and an estimate of costs are drawn up. The monthly maintenance and repair schedule sets the date the machine was stopped and the duration of its downtime in days. The initial data for the development of plans are data on the actual operating time (in hours) at the beginning of the planned year from the time of the corresponding type of maintenance and repair or from the start of operation (for a new machine); planned operating time of the machine for a year (in hours); indicators of the frequency of maintenance and repairs of each brand of machines. Data on the actual operating time of machines are taken on the basis of accounting, which organizations are required to keep systematically. The operating time of machines is determined according to the data of accounting for the shift time of the machines. Maintenance of main systems and assembly units Purpose and types of maintenance. Maintenance is carried out to maintain performance, reduce the wear rate of assembly units and parts, prevent the occurrence of defects, damage and failures and eliminate them in a timely manner, regardless of the technical condition of the loader and its assembly units. The frequency and scope of maintenance of loaders are established by regulatory and technical documentation. Maintenance includes washing, control and diagnostic, fastening, lubricating, adjusting, electrical and other works performed mainly without disassembling assembly units and removing them from the loader. According to the frequency and complexity of the work performed, the maintenance of forklifts is divided into: daily (EO), first (TO - 1), second (TO - 2) and seasonal (SO) maintenance. EO is one of the main types of loader care and is carried out regardless of the number of operating hours the loader has worked. The main purpose of the EO is the general control of the technical condition of the loader, maintaining the proper appearance, as well as refueling, oil, coolant and working fluid. SW is carried out after the end of the work of the loader, before leaving for the place of work, as well as in the process of work. TO - 1 and TO - 2 are performed periodically after the loader engine has run a certain number of hours. Manufacturers recommend the following maintenance intervals (in hours): Forklift 40912 .................................................................. ............... 120 4045R, 4014,4008M .............................. .... 100 MOT - 1 MOT - 2 480 500 The main purpose of the CO, carried out twice a year, is the preparation of loaders for operation in the cold or warm season. As a separate type of maintenance, CO is recommended for trucks operating in cold climates. Under normal conditions, SO is combined with TO - 2 or TO - 1 with a corresponding increase in the complexity of the main type of service. Daily maintenance. EO includes operations to prepare the forklift for work, as well as to care for it after returning to the parking lot. When preparing the loader for work, its external inspection and verification of the main units, mechanisms and assembly units are carried out. Forklift. They inspect the forklift frame, carriage and forklifts, they should not have dents or cracks. Check the reliability of fixing the forks on the carriage, as well as their free movement along the guides. They control the reliability of the attachment of the forklift to the frame of the loader and the attachment of the tilt hydraulic cylinders. Hydraulic drive. At the parking lot of the loader, check if there are any leaks of the working fluid through the connections and seals of the hydraulic system. They inspect the plunger of the lifting hydraulic cylinder and the rods of the tilt hydraulic cylinders of the forklift frame, identify whether they have longitudinal scratches, nicks, dents and other defects. Check the fluid level in the hydraulic tank. If necessary, add the working fluid to the required level. They inspect the places of seals of hydraulic pumps, hydraulic distributor, as well as connections of pipelines and flexible hoses of high and low pressure. Engine. After washing, the general condition of the engine is monitored; check its operation at a low crankshaft speed, the tightness of the cooling, power and lubrication systems, the presence of noise and knocks. On the day of the general assessment, the engine is started, warmed up, and the condition of the engine is determined by the tone and strength of the noise. Before leaving the loader, check the level of water or coolant in the engine cooling system. Engine oil filters. The filter plates of coarse filters are cleaned of dirt and resinous deposits. To do this, on a warm engine, turn the handle of the filter element 3 ... 4 turns in any direction: the cleaning plates remove deposits from the filter plates. It is forbidden to use a knob extension to facilitate turning the filter handle. If the filter handle is difficult to turn, it is necessary to unscrew the cover bolts, remove the filter and wash it in kerosene. Parking brake. Check the operation of the parking brake and adjust if necessary. Steering. Check the tightness of the connections of the hydraulic power steering system. Fluid leaks must be repaired immediately. Electrical equipment. Accumulator battery. An external examination checks the cleanliness of the surfaces of the monoblock, the absence of cracks in it and the leakage of electrolyte. Do not allow contamination of the battery surface, cracks in the monoblock and mastic, electrolyte level decrease, significant battery discharge, terminal oxidation and loosening of the wire lugs and the battery in the socket. Ignition coil. During the EO and each subsequent maintenance, the coil is cleaned of dirt, oil and dust and wiped with a dry cloth. Make sure that the ignition is switched off when the loader engine is not running. With the ignition on and the contacts closed, current from the battery will flow through the coil and overheat it, and the battery will be discharged. Starter. Check starter operation. The absence of knocks when turned on indicates that the starter gear freely engages with the flywheel ring gear and automatically disengages after the loader engine starts. Relay-regulator. The operation of the relay-regulator is controlled by the readings of the charge control lamp, the condition of the batteries and lighting fixtures. Ignition and starter switch. Check the shutdown mechanism by turning the key to the left, first right and neutral positions. In this case, a click should be heard, since the indicated positions of the switch mechanism are fixed. After setting the key to the second right position, it is released, the key and, together with it, the switch mechanism, under the influence of the force of the return spring, must return to the first right position. Breaker-distributor. Check the cleanliness of the contacts of the breaker-distributor, their serviceability and the presence of lubrication between the rubbing parts. To lubricate the breaker-distributor, it is forbidden to use oil from the engine crankcase. The presence of excessive lubrication in the breaker-distributor is harmful, as it can lead to rapid wear of the contacts when oil gets on them and failure of the breaker-distributor. It is necessary to constantly monitor the cleanliness of the parts of the breaker-distributor, especially insulating ones, such as the cover, rotor, terminals and others, as well as the reliability of the connection of high voltage wires with the terminals of the distributor cover and the ignition coil. Wiring. External inspection check the condition of the electrical wires. If a bare low-voltage wire is found, it is insulated with insulating tape. High voltage wires with broken insulation are replaced with new ones. To determine a wire break, use a test pen lamp, one contact of which is connected to the wire clamp, the other to the pin. Cabin. Check the condition of the windows, the presence of a rear-view mirror and the serviceability of the door locking mechanisms. Check the operation of the wiper, fan, heater, speedometer and other devices. In addition, they check the condition of the metal structures of the cabin, the presence of license plates. Wheels and tires. Before leaving, check the condition of the tires, the serviceability of the valves and the presence of caps on them. Tire pressure must be checked at least once every 5 days. Do not reduce tire pressure if it increases due to heat, especially in hot weather. The gap between the sidewalls of the front axle tires should protect them from mutual contact when they are deformed under rated load. It is forbidden to operate the loader with reduced tire pressure, as this will cause the tires to fail quickly. The parking lot of the loader must not be contaminated with oil products and other substances that destroy rubber. Do not allow the working fluid and oil from the mechanisms to get on the tires of the loader. After work, the loader is cleaned of dust and dirt, in winter - of snow. If necessary, wash the loader. The efficiency of washing operations is significantly increased with the use of specialized equipment. After washing, the loader is wiped with a soft flannel. Thoroughly wipe glass, external signaling and lighting devices, cabin, fenders, license plate. After washing the loaders in winter, special attention should be paid to removing moisture to prevent freezing. First maintenance. At TO - 1, all the work provided for by the SW is performed, and the work additionally indicated below. Engine. The technical condition of the engine is checked without disassembly, listening to it with a stethoscope. If knocks are detected in a particular zone, the possibility of further operation of the engine is assessed. Crank and gas distribution mechanisms. The elements of the crank mechanism of the engine include cylinders, pistons, rings, connecting rods, crankshaft and bearing shells. The good technical condition of the cylinder-piston and connecting rod-piston groups is evidenced by the presence of compression, the absence of oil burning, gas breakthroughs into the crankcase and the absence of knocks and vibrations. At TO - 1, the fastening of the engine cylinder head is checked. Tighten bolts and nuts on a cold engine in several steps with a torque wrench, controlling the tightening torque and following the sequence, starting from the middle to the edges and crosswise. When tightening the cylinder head bolts, it is necessary to check the possible change in the gaps between the rocker arms and valves. Tighten the cylinder head cover nuts evenly to a torque of 5 . .. 6 N m (0.5 ... 0.6 kgf m). Increasing the tightening torque of the cover will deform the rubber gasket installed underneath. On a new loader, retighten the nuts and bolts of the engine cylinder head regularly every 50 hours during the first 300 hours of operation. Checking compression in the engine cylinders. As the piston rings and cylinder walls wear, the pressure in the engine cylinders (compression) decreases. Compression is checked with a warm engine using a compression gauge. To check the compression, it is necessary to clean the dirt that has collected in the spark plug recess, disconnect the wire from the spark plug and unscrew it, open the choke valve and carburetor throttle to the full, insert the rubber tip of the compression tester hose into the hole of the spark plug of the first cylinder and press it firmly, turn it at With the help of the starter, the crankshaft, making several revolutions so that the compression gauge registers the maximum pressure in the cylinder, remove the rubber tip of the compression gauge from the spark plug hole, record the readings, open the exhaust valve of the compression gauge and release air, repeat the operations for the remaining cylinders. With a pressure difference of more than 0.07 ... 0.10 MPa, 20 ... 25 cm3 of fresh oil is poured into the cylinder and the compression is checked again. If the compression increased at the same time, this indicates the presence of air leakage through the piston rings. If the compression after filling the cylinder with oil remains the same as when measuring without oil, this indicates a loose fit of the valves to the seats or their burnout. A sharp decrease in compression (by 30 ... 40%) with tightly fitting valves indicates a breakage of the rings or their occurrence in the piston grooves. Engine power system. Check the reliability of the connection of the rod with the levers of the throttle and air dampers and, if necessary, adjust the length of the corresponding rods. Check the condition of the rubber pipe connecting the engine air filter to the hood. Inspect power supply devices and eliminate possible malfunctions. The air filter is disassembled, the filter element is washed with kerosene and assembled, after filling the filter housing with the required amount of oil. They check the fastening of the fuel tank plug and the operation of the plug valves, the serviceability and cleanliness of the strainer in the filler neck, tighten the fastening of the tank and remove sediment (water, dirt and tar deposits) through the drain plug hole. If sediment is not drained from the tank in a timely manner, the tank may rust, and if contaminated fuel enters the carburetor, the loader engine will malfunction. At TO - 1, the tightness of the fuel pump should be checked and the fuel leak should be eliminated. The cause of fuel leakage from the opening of the pump housing when the plug is unscrewed may be a break in the diaphragm, which in this case is replaced. The fuel supply pressure developed by the pump is checked using a pressure gauge, which is connected to the fuel line supplying fuel to the carburetor. After the loader engine is turned off with the valves in good condition, the pressure drop in 30 seconds should not exceed 0.01 MPa. Check the tightness of the fasteners and the serviceability of the drives of the air and throttle valves of the carburetor. It is forbidden to use wire, metal objects or cleaning materials to check the jets. To avoid damage to the float, it is forbidden to blow the assembled carburetor with compressed air. Checking and adjusting the carburetor. In case of insufficient fuel supply by the carburetor, it is necessary to check the serviceability of the intake manifold gasket and the absence of air leaks in the pipeline and the carburetor, the serviceability of the fuel pump (checked by the manual pumping lever with the fuel line disconnected), the correct opening of the throttle valves (if the throttle valves do not open fully, it is necessary to adjust the drive rods) . If the fuel pump is working and there is no air leakage through the gaskets, the cause of poor fuel supply should be sought in the carburetor itself. To do this, turn out and check the strainer, and if it is not clogged, check the channels of the fuel supply valve assembly. To inspect and clean the channels of the fuel supply valve assembly, it is necessary to remove the air filter, disconnect the air damper control cable, remove the carburetor cover, check the condition of the channels, rinse them with clean gasoline and blow with compressed air. To check and clean the jets, remove the carburetor from the loader, unscrew the plugs from the channels of the full power jets and from the channels of the mechanical economizer. Then blow out jets and carburetor channels with compressed air. Blowing compressed air through the assembled carburetor through the fuel inlet, balance tube or other holes is not allowed, as this may lead to collapse of the float. After checking and cleaning the channels and jets, the carburetor is assembled, installed on the engine and the fuel supply is checked when the engine is running in various modes. With increased fuel consumption, it is necessary to check the completeness of the air damper opening and the fuel level in the carburetor. To do this, the control plug is turned out of the body of the float chamber and the fuel level is checked when the engine is idling at a low speed. Before adjusting the carburetor, the engine must be warmed up and the ignition devices must be checked for proper operation. Particular attention should be paid to the serviceability of the spark plugs and the gap between their electrodes. Engine lubrication system. They check the level and quality of the oil, change the oil, purify it and, if necessary, replace the filter elements of the oil purification filters. The level and quality of the oil is checked no earlier than 5 ... 10 minutes after the engine is stopped. After removing and wiping the oil measuring rod, insert it all the way and remove it again. The oil level is determined by the marks on the rod: it should be (with filled oil filters) at the level of the upper mark of the oil measuring rod. If the oil is at the level of the lower mark, it is necessary to add it. When changing the oil in the crankcase of the engine, the used oil is drained until the engine has cooled down. The hot oil drains easily and washes away dirt from the crankcase walls. At the same time as changing the oil in the crankcase, it is necessary to replace the fine filter. Fresh oil is poured through the filler neck. After filling with oil, it is necessary that the engine runs at an average crankshaft speed until the lubrication system is filled, then the engine is stopped and the oil level is checked on the oil dipstick. For loaders 4043M; 4045P; 4013 and 4014 (manufactured in 1976 and later), every 150 hours of operation, during the next oil change in the engine, the filter element of the full-flow fine filter is also changed and the oil sludge is drained from the filter housing by unscrewing the drain plug with a wrench. Before installation, a new filter element must be blown with compressed air to remove cardboard pieces, hairs and lint, which settle between the cardboard plates and further clog the oil lines. After replacing the filter element, check the oil level in the crankcase and add oil if necessary. At TO - 1, the crankcase ventilation air filter is refilled simultaneously with the oil change in the crankcase of the loader engine. Before refueling, the crankcase ventilation filter is disassembled, cleaned of dirt and thoroughly washed with gasoline or kerosene. Then oil is poured into a clean container and the filter mesh is immersed halfway into the oil. The grid is removed from the oil, shaken and inserted into the filter housing and its cover is replaced. Oil filters. When changing the engine oil, the oil filters must be cleaned. To do this, on a warm engine, the plug is unscrewed from the coarse oil filter housing and sludge and pollution products are released. After installing the plug in place, start the engine and let it run for several minutes until the filter housing is filled with oil, after which oil is added to the engine crankcase to a normal level. Engine cooling system. Check the tension of the fan drive belt and, if necessary, set the nominal value. The deflection of the belt is determined by attaching a ruler to its middle and pressing it with a force corresponding to the pressing force with the thumb (approximately 30 ... 40 N). With a weak belt tension, the engine overheats, and if it is excessive, the bearings of the water pump and the belt itself wear out. Lubricate the water pump drive shaft bearing in accordance with the lubrication chart. Front drive axle. Check the fastening of the covers and the main gear housing, as well as the fastening of the flanges of the axle shafts. Check the oil level in the crankcase and top up if necessary. Power transmission, clutch. During maintenance of the clutch, control and adjustment work and lubrication are performed. Check and adjust pedal free play to ensure full clutch engagement and disengagement. Pedal free play is determined by the clearance between the thrust bearing and the release levers; for loaders 4043M, 4045P, 4013, 4014 it is 35 . .*. 45 mm; for loader 4008 - 30 ... 35 mm and for loader 4022 - 35 ... 45 mm. The full travel of the pedal is determined by the distance from the pedal to the floor. At TO - 1, the clutch pedal axle bushings and clutch release bushings are lubricated, for which synthetic lubricants are used. Fresh lubricant is pumped through the oilers until the old lubricant is completely squeezed out. Transmission. Check the oil level in the gearbox and top up if necessary. The oil level must reach the filler hole. It is allowed to lower it from the lower edge of the filler hole by no more than 10 mm. Cardan transmission. Check the condition of the bolts of the cardan shaft flanges and, if necessary, tighten them to failure. Periodically check the fastening of the bolts of the bearing caps and, if necessary, tighten them. The tightening torque must be 10 .. 15 Nm (1 . . . 1.5 kgf m). This ensures that the needle bearings in the yokes and the spiders in the bearings fit properly. After tightening, the bolts are fixed, the antennae of the lock plates are bent. With a significant radial and end clearance in the bearings of the crosses, the entire cardan shaft assembly is replaced. The bearings of the crosses of the cardan shafts are lubricated. The oil used for the gearbox is used as a lubricant. Oil is fed into the crosspiece using an oiler until the old oil exits through the safety valve. Steering. They check the free play of the steering wheel and, if necessary, adjust the steering mechanism, lubricate and tighten the joints of the steering rods and levers, eliminate the leakage of working fluid from the hydraulic booster and pipelines. engine running and crankshaft rotation at low frequency. In this case, the rear wheels are set in a position corresponding to the rectilinear movement of the loader. The steering wheel free play must not exceed 20°. Parking brake. They check the condition and operation of the parking brake, tighten the fastening of the gear sector, drive parts, check the fixation of the lever during full braking and the amount of lever travel. If the amount of lever travel is insufficient, the brake is adjusted. Forklift. Check the tension of the carriage lift chains and adjust if necessary. External inspection of the forklift frame and carriage check for cracks in the welds. At TO - 1, check the tightening of the lock nut and the locking screw for fastening the axis of the swinging traverse and, if necessary, tighten it to the norm. Hydraulic drive. Clean the inlet and outlet filters of the hydraulic system. To do this, they are removed from the hydraulic tank, cleaned of accumulated dirt with a crane brush, washed in kerosene and blown with dry, clean compressed air. The suitability of the working fluid for further operation is determined by samples taken from the hydraulic tank. The amount of impurities allowed in the working fluid should not exceed 0.032% by weight. They check the reliability of the fastening of the hydraulic pumps, the hydraulic pump gearbox and its drive, as well as the tightening of the bolts for fastening the flanges of the propeller shaft of the gearbox drive. Electrical equipment. Accumulator battery. The surface of the battery is cleaned of dust, dirt and electrolyte with a clean rag soaked in a 10% solution of ammonia or caustic soda, and then wiped with a dry cloth. Check and, if necessary, clean the ventilation holes in the plugs from dirt and ice. Eliminate cracks on the surface of the monoblock. Check the fastening of the battery and wires. Lead pins are cleaned of oxides, and their non-contact surfaces after connection are lubricated with technical petroleum jelly. Ignition coil. Check the reliability of the fastening of the wires, the bracket and the ignition coil itself to the bracket. Generator. They clean the outer surface of the generator, check the fastening of the wires, the tension of the drive belt and the reliability of the fastening of the generator and the pulley on the shaft. Starter. They clean the starter housing from oil and dirt, check the fastening of the starter to the engine and, if necessary, tighten the mounting bolts; check the operation of the switching mechanism, clean the terminals and tighten the wires to the starter, traction and auxiliary relays, to the battery and from the battery to ground. Relay-regulator. They check the tightening of the terminal screws and the fastening of the wires, clean the body of the relay regulator from dirt, dust and tighten the fastening of the body to the rear wall of the cabin. Ignition and starter switch. The serviceability of the switch contacts is checked by the voltage drop across the terminals. To do this, connect the switch under test to the test electrical circuit (Fig. a). Rice. Scheme for switching on devices when checking the ignition switch: a - by measuring the voltage drop, b - by a test lamp One conductor of the circuit is connected to the AM terminal of the switch, and the second - in turn to the short circuit, ST, PR terminals. Move the slider of the rheostat to the position of turning on the impedance. Set the switch in turn to all working positions, turn on the circuit and set the current to 10 A with a rheostat. the switch with a control lamp is produced according to the scheme shown in fig. b. The lamp should burn when connected only to those terminals of the switch that are included in the circuit at each operating position of the key. To connect the KZ and PR clamps to the circuit, the key is set to / the right position, the KZ and ST clamps - to the // right position, and to connect only the PR clamp to the circuit - to the left position. The breaker-distributor is cleaned of dirt, moisture and oil, the distributor cap is removed and wiped with a rag soaked in unleaded gasoline. In the presence of corrosion on the terminals of high voltage wires, they are cleaned with sandpaper. Check the cleanliness of the breaker contacts and, if necessary, remove dirt and oil from them. To do this, wipe the contacts with suede soaked in clean unleaded gasoline, pull back the lever and let the gasoline evaporate, and then wipe the contacts with clean, dry suede. When cleaning contacts, instead of suede, you can use any material that does not leave fibers on the contacts. Check the condition of the working surface of the contacts and clean them if a significant amount of metal has passed from one contact to another or the formed tubercle on the contact makes it impossible to measure the gap between the contacts. It is necessary to clean the contacts with a thin (about 1 mm) abrasive plate or abrasive sandpaper with a grain size of M40. It is forbidden to use abrasive paper with a larger grain size, needle file and other means to clean the contacts. When stripping the contacts, remove the tubercle on one of them. After stripping, the contacts should be washed, dried and the gap between them adjusted. After lubricating the breaker-distributor, check if the lever on the axle is stuck. To do this, press the lever and release. The lever under the action of the spring should quickly return to its original position, and the contacts should close with a click. If the contacts do not close or the lever moves slowly, it is necessary to eliminate the jam and adjust the tension force of the breaker spring within 5 ... 6 N (500 ... 600 gf). To do this, remove the lever and carefully bend the spring in one direction or another, if necessary. When installing the breaker-distributor on the loader, it is necessary to check the ignition installation, check and, if necessary, adjust the gap between the contacts. The normal gap between the contacts should be 0.3. .. 0.4 mm. Spark plug. Remove the spark plugs and check their condition. Candles must be clean, dry and sealed. The insulator of the candle should not be cracked, and the glaze covering it should not be scratched. Next, a wire probe checks the spark gap between the side and central electrodes. The use of flat probes is not allowed, as it gives an incorrect result (the measured gap is less than the actual one). The normal gap between the side and central electrodes should be 0.5 ... 0.6 mm for CH307 candles, 0.85 ... 1.0 mm for A15B candles and 0.6 ... 0.7 mm for candles A16U and A16C. Lighting devices, light and sound signaling. They check the fastening of the headlights, sidelights, taillight, central light switch, direction indicator switch, fastening and condition of the insulation of the wires of the headlights and sidelights, and the reliability of the fastening of the wire lugs with the terminals. Clean the surfaces and terminals of the light foot switch and brake light switch from dust and dirt. They check the reliability of fastening the sound signal and the tightening of the terminals, and also clean the sound signal from dust and dirt. Second maintenance. At TO - 2, they perform all the work provided for by the EO, TO-1, lubrication map, and additionally perform the following work. The loader (as a whole) is thoroughly washed and all its mechanisms are inspected. Produce a control run at a distance of 3 ... 5 km. While driving, check the oil pressure; water temperature in the cooling system; the operation of the brakes, gearbox, clutch, steering, engine idling and under rated load, wiper. Check the degree of heating of the brake drums of the front and rear wheel hubs, as well as the gearbox. Engine. Check the fastening of the radiator, its lining and the hood lock; serviceability of blinds and their drive; compressor mounting and operation; fastening the pulley, fan impeller and water pump; condition and fastening of inlet and outlet pipelines and muffler pipes, oil pan, lower and side mudguards; fastening of the heater, fuel tank and heater control panel; cleanliness of the crankcase ventilation valve. Removing the engine crankcase, clean the oil receiver mesh. Check and adjust the size of the thermal gap between the valve and the rocker arm of the valve mechanism. The clearance is adjusted on a cold engine (at a temperature of 15 ... 20 ° C) with the valves completely closed, when the piston is at top dead center at the end of the compression stroke. For the first cylinder, the specified piston position is found by the corresponding marks on the engine. The clearances in the valves of subsequent cylinders are adjusted in accordance with the order of operation of the cylinders. Engine cooling system. Check and adjust the shutter drive. Violation of the normal operation of the drive or jamming of the hinges of the shutters of the blinds is often the result of their contamination. In this case, the leaf hinges are washed with kerosene, blown with compressed air and lubricated with engine oil. The blind drive cable is removed from the sheath, washed, the curvatures present on it are straightened, lubricated and, having installed in the sheath, are fixed in the flap drive lever. After that, adjust and set the required amount of travel of the drive cable. At TO - 2, as well as when violations of the temperature regime are detected in the process of performing any type of maintenance, the condition of the thermostat valve is checked. To do this, remove it from the engine, clean it from scale and place it in a vessel with water, in which there is a control thermometer. By heating the vessel on an electric stove, the temperature at which the thermostat valve starts to open is determined. When the thermostat valve is raised by 9 ... 10 mm, it opens completely. After removing the vessel from the heater and cooling the water, check the closing temperature of the valve, which should be approximately 65 °C. A defective thermostat must be replaced. Engine power system. Wash the filter element of the fuel filter-sump. To do this, having closed the fuel tank cock, unscrew the filter cover fastening bolt and disconnect the sediment filter housing together with the filter element. If leaded gasoline was used on the loader, you must first unscrew the plug and drain the gasoline, preventing it from getting on your hands and clothes. When disassembling the sediment filter, you should pay attention to the condition of the gasket that ensures the tightness of the housing with the cover. A damaged gasket can be replaced with a new one by making it from thick cardboard soaked in drying oil. Next, remove the filter housing, wash it with unleaded gasoline and check the condition of the parts. The filter element plates must be undamaged. After assembly, check the tightness of the sediment filter under a pressure of 0.2 MPa, install it in place and tighten the bolt on the cover. In carburetors, they check the fuel level, the tightness of the float and the needle valve, the throughput of the jets, the operation of the crankshaft speed limiter and, if necessary, adjust the minimum crankshaft speed at idle. Before inspection work, the carburetor is removed from the loader engine, disassembled, its parts are cleaned of dirt and washed with unleaded gasoline. Jets and channels are blown with compressed air. It is not allowed to clean the jets with metal objects. Check the fuel level by measuring the distance from it to the plane of the carburetor connector. At TO - 2, it is recommended to drain the sediment from the wells of full power jets, from the well of the mechanical economizer and the float chamber of the engine carburetor. Engine lubrication system. Change the oil in the forklift engine. When operating in conditions of high dust content of the air, as well as with high engine wear and darkening of the oil, it should be replaced during maintenance - 1. The oil is changed on a warm engine, and the oil is drained from the crankcase and filter housings. Fresh oil is poured after washing the coarse filter. It is not allowed to contaminate the walls of the crankcase, the tray and the grid of the oil receiver. If the lubrication system is slightly contaminated, it is periodically washed without removing the oil pan. To do this, pour hot flushing fluid into the crankcase, turn out the spark plugs, crank the engine crankshaft for 1 ... 2 minutes and drain the flushing fluid from the crankcase. Then fill the loader engine with fresh oil and run it for a few minutes to fill the oil lubrication system. After stopping the engine, add oil to the normal level. Liquid mineral oils are used as flushing fluids - industrial I12A and I-20A (GOST 20799-75) or mixtures consisting of engine oil and 20% kerosene or 20 ... 50% diesel fuel . It is forbidden to flush the engine lubrication systems with pure kerosene, as this removes the oil film from the parts and deposits softened by kerosene on the crankcase walls clog the lubrication system. Oil filters. During maintenance - 2 and washing the engine crankcase on a loader 4022 and loaders 4043M.4045R, 4014 (produced in 1976), the coarse filter is cleaned. To do this, remove the sump, remove dirt and sticky sediment from it, wash it with kerosene and blow it with compressed air or wipe it with a rag. Before installing the sump, check the condition of the sealing gasket and, if damaged, replace it with a new one. When installing the sump, you should pay attention to the fact that the drain hole in it is located in a plane perpendicular to the plane of symmetry of the filter housing, otherwise access to the drain plug of the filter sump will be difficult. After installing the sump, evenly tighten the four bolts of its fastening. The filter element is easier to clean when the filter is removed from the engine. The filter sump must also be removed. Clean the filter element with a stiff hair or nylon brush with kerosene. It is forbidden to clean the filter element with metal scrapers or wire brushes, as this may damage its plates or the filter itself. After cleaning, the filter element is washed in unleaded gasoline and blown with compressed air. When installing the filter on the engine, it is necessary to change the gasket between the filter housing and the cylinder block, thoroughly cleaning the mating surfaces. It is recommended to lubricate the new gasket on both sides with sealant. To replace the filter element of the fine filter, unscrew the coupling bolt, remove the cover and spring, unscrew the drain plug and drain the oil. If the oil is heavily contaminated and a lot of sediment has accumulated in the housing, the filter housing must be washed. After that, the filter element is replaced with a new or remanufactured one, the drain plug is wrapped and fresh oil is poured into the filter housing. After that, add oil to the engine to the "P" mark on the level indicator, start the engine, check for oil leaks at the junctions of the filter parts and its pipelines, then stop the engine and add oil again to the "P" mark on the level indicator. At TO - 2, the engine crankcase is washed, on loaders 4014, 4045R (released in 1976 and later), the condition of the full-flow fine filter is checked. To do this, unscrew the drain plug and drain the sediment. If the oil is heavily contaminated and a lot of sludge has accumulated in the sump, the sump should be flushed. To do this, unscrew the coupling bolt, remove the sump together with the filter element, wash it with kerosene or unleaded gasoline and insert a new or remanufactured filter element into the filter sump. Having wrapped the drain plug, fresh oil is poured into the filter. After that, the filter is collected. During assembly, inspect the sealing gasket and replace if necessary. If an old gasket is used, then it should be put in the same position in which it was before removal to prevent leakage between the oil filter housing and the sump. After washing and assembling the filter, add oil to the loader engine to the "P" mark on the level indicator, start the engine, check for oil leaks at the junctions of the filter parts and its tubes, and then stop the engine and add oil again to the "P" mark on the level indicator. Front drive axle. Check the tightness and condition of the drive axle housing, fastening of the front bearing cap of the drive bevel gear shaft, side covers, gearbox housing and axle shaft flanges. At each TO-2, the total clearance of the main gear is also checked, which characterizes the wear of bearings and gears. The total clearance is determined by the clearance of the suspended wheel, which, with the parking brake applied on the rim, should not exceed 18 ... 25 mm for a new loader axle. As wear increases, the clearance increases. If the gap exceeds 45 mm, then using an indicator device, check the axial clearance by moving the drive gear in the axial direction from one extreme position to another. The axial clearance must not exceed 0.1 mm. If necessary, adjust the axial clearance of the main gear shaft bearings. After one TO-2, the lubricant in the wheel bearings is changed. To change the lubricant, it is necessary to remove the wheel hub, wash it and the bearings with kerosene, and distribute the new lubricant evenly between the rollers and cages over the entire inner surface of the bearing. Rear steering axle. The condition of the pivot pins and the rear axle beam is checked, and the radial clearance between the pivot pin and its bushings is determined. The gap between the kingpin 1 (Fig.) and its bushings 2 is determined by the displacement of the bead ring 5 of the wheel 6 relative to the bushings 2 of the rear axle 3 using the NIIAT T-1 instrument with adjusted wheel hub bearings. To do this, the rear axle is raised with a jack, wiped, and, if necessary, cleaned the lower part of the bead ring, against which the measuring rod of the indicator should rest. On the rear beam 3, the indicator 4 is fixed so that its leg is located horizontally and comes into contact with the lower part of the bead ring of the wheel. . Scheme for checking the clearance between the kingpin and its bushings: 1 - kingpin, 2 - bushings, 3 - axle, 4 - indicator, 5 - ring, b - wheel, 7 - gasket with some emphasis (preload), the arrow of the small indicator scale should stop against division 4 or 5 mm. After tightening all the nuts and screws of the device, turn the main scale of the indicator and set it to zero division against the end of the arrow. Slowly lowering the loader wheel to the floor, observe the movement of the arrow on the main indicator scale. According to the division of the scale, against which the indicator arrow stops, the radial clearance is determined. The radial clearance is allowed no more than 1.5 mm. If the clearance is larger, the bushing or kingpin must be replaced. The clearance between the rear axle boss and the upper lug of the pivot pin is measured with a flat feeler gauge inserted between the lug and the lug. For a new loader, the gap should be no more than 0.25 mm. During operation, it is allowed to increase the gap up to 1.5 mm. If necessary, the clearance is adjusted using a set of shims 7. Check the condition of the rear axle beam of the loader and the toe-in of the steered wheels, as well as the fastening of the pivots, the axial clearance between the rear axle beam boss and the pivot eye. The convergence of the rear steered wheels is checked using a special test ruler 2182. The loader is installed on an inspection ditch or on a flat horizontal platform, the rear wheels are set in a position corresponding to straight-line movement, the tire pressure is checked and, if necessary, adjusted to normal. The ruler, consisting of thin-walled telescopic pipes, is moved apart so that its length somewhat exceeds the distance between the tires. Then the ruler is installed in front of the rear axle between the wheels of the loader so that the stops touch the sidewalls of the tires, and the chains touch the surface. After that, the loader is rolled forward until the ruler is behind the rear axle at the same height as it was in front (the chains must also touch the surface). Under the force of the spring, which is located inside the ruler, its movable pipe will move, and the pointer will show on the scale the amount of wheel toe in millimeters. For loaders 4008 the convergence should be 5 ... 8 mm; for other loaders - 1.5 ... 5 mm. If the convergence does not correspond to the norm, then with the balancing suspension of the rear axle of the loader, it is adjusted by changing the length of the side rods separately for each of the wheels. At the same time, it is necessary to keep the same length of both side rods. The axial clearance between the rear axle beam boss and the upper lug of the stub axle is measured using a flat feeler gauge inserted between the boss and the lug. For a new loader, the gap should be no more than 0.95 mm. During operation, the gap can be increased up to 1.5 mm. If necessary, it is adjusted using shims. Checking and adjusting the maximum angles of rotation of the wheels. To measure the maximum angles of rotation, the rear wheels of the loader are mounted on the swivel disks of the device 2183 and the extension cords are connected to the rods of the swivel box indicator brackets. At each wheel, the boxes are installed in such a way that the indicator extensions fit snugly against the tires below the hubs, and the arrows of the indicators are against the zero divisions of the scales. The wheels of the loader, installed for straight-line movement and braked, turn all the way to the right and left and determine the angles of rotation. If necessary, adjust the angles with the help of stop screws screwed into the steering knuckles. For adjustment, loosen the lock nut and, turning the bolt, set the desired angle of rotation. Do the same for the other loader wheel. At the end of the adjustment, the locknut is tightened, the device is removed. Checking the limit angles of rotation of the right wheel is carried out in a similar way. Steering. They check the fastening of the steering gear housing to the chassis frame, the bipod on the shaft and the steering link cup, as well as the serviceability of the power steering when turning the wheels in both directions. Parking brake. Check the tightening of the brake drum fastening nut on the driven shaft of the loader reverse mechanism. Once a year, the parking brake is disassembled, the parts are cleaned and their condition is checked. The axis of the pads and the rubbing parts of the drive are lubricated with a thin layer of grease and the position of the pads is carefully adjusted. At the same time, the gap between the pads and the drum is reduced, which is increased due to the wear of the linings. Cardan transmission. The spline joint of the cardan shaft is lubricated. At the same time, the driveline is disassembled and the internal cavity of the splined fork and the splined shaft are washed with kerosene. The parts are blown with compressed air and 150 ... 200 g of grease C or press grease C are placed in the internal cavity of the sliding fork. The cardan shaft is assembled and the stuffing box cap is tightened to failure. Gearbox and reverse gear box. In the crankcases of the boxes, the oil is replaced. To do this, unscrew the drain and filler plugs and drain the used oil into a container. Then wrap the drain plug and fill in fresh oil in an amount corresponding to the volume of the crankcase. When changing the oil, it is necessary to ensure that sand, dirt, chips and other objects do not get into the boxes, which can cause jamming and wear of the gear seats loosely seated on the driven shaft. Loader hydraulic drive. They check the operation of the loader with a rated load on the fork lift, using a pressure gauge, measure the pressure of the working fluid in the hydraulic system. Check the maximum pressure in the hydraulic system of the loader and, if necessary, adjust the relief valve of the hydraulic distributor. They also check the working condition of all elements of the hydraulic system: hydraulic pumps, hydraulic cylinders, hydraulic distributors, hydraulic tank, valve blocks of the power steering and forklift, power steering, pressure valve, filters and locking devices, rotary couplings for connecting replaceable working devices, as well as the condition of pipelines and flexible hoses. The condition of the hydraulic pumps of the forklift loader is determined by the maximum speed of lifting the load and the rated pressure when lifting the rated load. The serviceability of the power steering hydraulic pump is judged by the force applied to the steering wheel of a loader moving on a horizontal platform with a smooth and dry asphalt or concrete surface. The force value must not exceed 80 N (8 kgf). The serviceability of the hydraulic cylinder for lifting the load is judged by the absence of leakage of the working fluid in the plunger seals and damage to the plunger surface (longitudinal scratches, scuffs and bottomholes). The serviceability of the hydraulic cylinders of the tilt frame of the load lifter is determined by ensuring the full tilt of the frame forward and backward with a nominal load on the forklifts in 3 ... 5 s at an average speed of the crankshaft of the loader engine, the absence of damage to the hydraulic cylinder rods (longitudinal scratches, scuffs and nicks), and also by the absence of leakage of the working fluid through the seals of the rods. The serviceability of the hydraulic distributor is checked by turning on the actuators using the handles. After removing the load from the handle, it should return to the neutral position. In the extreme working positions, the handles must be held by a force not exceeding 60 N (6 kgf). External leakage of the working fluid from the hydraulic distributor is not allowed. In the hydraulic tank, they check for cracks in the body, leakage of the working fluid through gaskets and connections. In a serviceable hydraulic tank, the outer surface must be clean and dry. At TO-2, if necessary, regulate the safety and bypass valves, and also check the tightness of the connections. If leaks of the working fluid are detected, replace the rubber o-rings. The serviceability of the valve block of the lifting hydraulic cylinder is determined by the magnitude of the spontaneous lowering of the rated load with the lifting hydraulic cylinder and pipelines in good condition. In this case, the hydraulic distributor handle must be in the neutral position, and the loader engine must be turned off. The amount of lowering of the nominal load should be no more than 100 mm in 10 minutes. At TO-2, the operation of the hydraulic system of the loader is checked. To do this, remove the drain filter from the hydraulic tank, remove the retaining ring and cover and remove the filter elements from the housing, which are washed with kerosene and blown with dry, clean air. The filter elements are inspected and if they have cracks, tears, chippings, they are replaced. Check filter relief valve setting. The inlet filter is removed from the hydraulic tank, cleaned of accumulated dirt with a nylon brush, washed with kerosene and blown with dry clean air. Inspect the mesh of the filling filter. In the presence of tears and holes, the mesh is replaced or repaired. Check the condition of rubber hoses and pipelines. On the sleeves, damage or undercuts of the metal braid, bulging of rubber, twisting of the axis of the sleeves, swelling and other damage are not allowed. Cracks, deformation and other damages are not allowed on pipelines. Defective hoses and pipelines should be replaced. Determine the presence of water in the working fluid. To do this, liquid is poured into a test tube, closed with a stopper, into the hole of which a thermometer is inserted, and heated to 150 °C. In the presence of water, the liquid foams, crackling is heard, the oil layer on the walls of the test tube becomes cloudy. Forklift. Check the tension of the carriage lift chains and adjust if necessary. They inspect the upper rollers of the chains, check for cracks in the flanges, one-sided wear of the working surfaces, marks and other defects. Next, inspect the chains and check for cracks in the links and plates. Damaged plates must be replaced. Check the rotation of all rollers of the carriage and the forklift frame. The rollers must rotate freely and evenly without jamming by hand. Check the condition of the rollers. They should not have cracks, uneven wear, scuffing, chipping and other defects. After that, the gaps between the frames of the forklift and the carriage are checked and, if necessary, adjusted. With a torque wrench, check the tightening of the threaded connection of the fastening of the forklift frame to the loader frame. They inspect the place of attachment of the hydraulic cylinder for lifting the load to the lower cross member of the frame and check the tightening of the threaded connection, the condition of the springs, bolts and thrust bearing. Check the attachment of the tilt cylinder rods to the forklift frame, tighten them if necessary. Check the fastening of the guide cheeks of the inner frame for the free movement of the carriage, determine the deformation and wear of the throat of the guide cheeks, measure the bending of the shelves of the inner and outer frames of the load lifter On loaders 4046M; 4016; 4055M; 4017 and 4008 check the wear of the blockless boom hook mouth. If more than 10% of the original section is worn, the hook is replaced with a new one. Using a square, check the bending of the lower shelves of the fork lift. The permissible increase in the bending angle at a nominal angle of 90° should not exceed 3°. Electrical equipment. Accumulator battery. The degree of discharge of the battery is checked by measuring its voltage and comparing the actual density of the electrolyte with the standard one. To determine the degree of discharge of the battery by changing the density of the electrolyte, it is necessary to know what density of the electrolyte was in the battery at the charging station, and also whether the high-density electrolyte was added to it during operation. The electrolyte level is checked every 10 ... 15 days in winter and every 5 .. 6 days in summer. It should be borne in mind that at an air temperature of 30 ° C, due to the evaporation of water from the electrolyte, its level in the battery decreases by about 1 mm per day. When the electrolyte level drops, distilled water is added to the battery while the loader engine is running. In order for the water to move with the electrolyte, the engine must run for 10 ... 15 minutes at an average crankshaft speed. It is strictly forbidden to use tap water, as it contains impurities (iron, chlorine, etc.) that destroy the battery. If the electrolyte level has decreased due to leakage, then the electrolyte of the same density is added to the battery. When the electrolyte is contaminated, the battery is discharged. Such a battery should be discharged with an electric current equal to 0.1 of the battery capacity, to a voltage of 1.1 ... 1.2 V per battery. This is necessary so that foreign metals and their oxides that have entered the battery are transferred from the active mass of the negative plates to the electrolyte. After that, the entire electrolyte is poured out and the batteries are filled with pure electrolyte of the same density, and then the battery is fully charged. The electrolyte level should be 10 ... 15 mm higher than the safety shield installed above the separators. The electrolyte level is measured with a glass tube with an inner diameter of 3 ... 5 mm, which has an appropriate mark. To do this, lower the tube vertically into the filler neck of the cap until it stops against the safety shield, close it from above with your thumb and then remove it. The height of the electrolyte column in the tube corresponds to the electrolyte level above the safety shield. The density of the electrolyte is used to judge the degree of discharge of the battery, given that a decrease in density by 0.01 t/cm3 corresponds to a discharge of 6%. If at the end of the charge the density of the electrolyte in the battery is lower or higher than the allowable values, its density is changed, if the density is higher than the norm (1.4 g/cm3), then distilled water is added, if the density is lower than the norm, then the electrolyte. After topping up, it is necessary to continue charging the battery for 25 ... 30 minutes to completely mix the electrolyte and again measure its density. Then check the electrolyte level in all batteries of the battery. Relay-regulator. The operation of the relay-regulator is checked directly on the loader using a portable electrical universal device NIIAT E-5. Generator. Check the tightening of the studs, fastening of the covers and the generator. After one TO-2, the protective tape is removed, the brushes, brush holders, collector are inspected and the cavity of the generator housing is blown with compressed air. Once a year, the generator is removed from the engine, disassembled and cleaned. Inspect covers, brushes, anchor and collector; check the condition of the excitation and armature windings. If necessary, lubricate the generator bearings. To do this, remove the covers and bearing, lay refractory grease. Worn brushes that are less than 17 mm high and have significant damage to the working surface are replaced. New or poorly fitting brushes to the collector are wiped. To do this, between the brush and the collector, a strip of abrasive skin with a grain size of M40 is pulled against the direction of movement of the anchor, facing the grain to the brush. The width of the skin should be greater than the width of the brush. After wiping the brushes, the generator should be blown out with compressed air. It is necessary to ensure that the brushes in the brush holders move freely, without jamming. Jamming of the brushes increases sparking and leads to burning of the commutator. If the collector burns, it must be cleaned with an abrasive sandpaper with a grain size of M40. The breaker-distributor is lubricated, while 2 ... 3 drops of oil are applied to the lubricating wick of the cam, to the bushing of the axis of the breaker-distributor, to the wick of the breaker-distributor shaft, then turn the cam oiler cover one turn, supplying refractory grease to the central shaft . In order to avoid splashing the breaker contacts with oil, it is not allowed to lubricate its parts abundantly, and also use diluted oil from the loader engine crankcase to lubricate them. To check the operation of the breaker-distributor during operation directly on the loader, it is recommended to use a portable electrical universal device NIIAT E-5. The starter is removed from the loader engine. The internal cavity of its housing is blown with compressed air, the condition of the brushes, the collector, the switching contacts, the return spring, the drive mechanism are checked, and the coupling bolts of the housing are tightened. If the collector is contaminated and the contacts are burned, they are wiped with a rag soaked in unleaded gasoline, and in case of significant pollution and burning, they are cleaned with an abrasive sandpaper with a grain size of M40. The use of skins with a larger grain size is not allowed. After stripping, the starter is blown with clean compressed air. Wash the drive mechanism with kerosene and lightly lubricate the drive gear bushings with oil used for the loader engine. With a significant roughness of the collector, the anchor should be sent for repair. Check the force of pressing the spring on the brushes and, accordingly, the force of pressing the brushes on the collector. After making sure that the starter is in good condition, check the adjustment of the mechanism for its inclusion. Ignition coil. At all operating modes of the loader engine, the ignition coil must create a voltage sufficient to break through the spark gap between the spark plug electrodes. During TO-2 and when there are interruptions in the operation of the coil, it is checked. To check the primary winding and the additional resistor, it is necessary to connect the battery with the wires through the light bulb to the terminals P and VK-B of the coil. If the light does not light up, the wire from the VK-B terminal is switched to the VK terminal. The glow of the light bulb indicates a malfunction of the additional resistor. To check the secondary winding, the ignition coil is connected to a 220 V network. In this case, one wire is connected to the high voltage terminal, and the second to the P terminal at a distance of 6 ... 7 mm. An electric spark indicates the health of the secondary winding. If the winding is damaged, the coil is replaced. Wiring. They carefully check the condition of the insulation of electrical wires, the reliability of their fastening, the condition of the terminals and clamps, the serviceability of the fuses, and also control the voltage drop in the circuits of electrical equipment, which should be 0.5 .... 0.7 V. Lighting devices, light and sound alarms . Check the operation of all control devices, sound signal, installation and adjustment of headlights. Cabin. Check the condition of the seats and the mechanism for adjusting the position of the driver's seat. They also check the serviceability of the glass lift, doors, locks and door handles, and the operation of the wipers. Seasonal maintenance (SS) is carried out twice a year in autumn and spring. Before the CO, all the work provided for by TO-2 is performed, and the following work is additionally carried out: Engine. Check the condition of the cylinder-piston group. Carbon deposits are cleaned mechanically using softeners. The removal of deposits in the cylinders can be done with or without removing the cylinder head. When removing the cylinder head, carbon deposits are removed with scrapers, metal and hair brushes and rags, after softening it with kerosene. Carbon deposits on parts made of aluminum alloys can be softened by immersing them for 2 ... 3 hours in a solution heated to 90 ... 95 ° C, consisting of 10 liters of water, 20 g of soda ash, 100 g of liquid soap and 100 g of liquid glass . After removing carbon deposits from the valves, their condition should be checked and, if necessary, lapped. The soot formed when running on leaded gasoline is poisonous. Cylinder heads, exhaust pipes and other parts removed from the loader engine (except parts made of aluminum alloys) can be cleaned of carbon deposits in a salt melt consisting of 65 ... 70% sodium hydroxide, 25 ... 30% sodium nitrate, 5 % sodium chloride. To remove carbon deposits from the combustion chamber without removing the cylinder head, 150 is poured into each cylinder of a warm engine. . . 200 cm3 of a mixture consisting of 80% kerosene and 20% engine oil, replace the spark plugs, crank the crankshaft several times. After 10 ... 12 hours, the engine is started for 20 ... 30 minutes, during which the softened soot burns out. Instead of the specified mixture, 30 can be used. .. 50 cm3 of denatured alcohol, and before starting the engine, pour a little oil into the cylinders. After removing carbon deposits, it is necessary to change the oil in the crankcase, replace the spark plugs and, before starting the engine, pour 20 ... 30 cm3 of fresh oil into each cylinder. Supply system. Flush the fuel tank and fuel lines. To remove resinous deposits, dirt and suspended particles from the tank at least twice a year, the sediment is drained from it and once a year, in the fall, the tank is removed and washed. Flush the tank with hot water, low pressure steam, unleaded gasoline, kerosene or solvents (white spirit). The presence of rust in the drained sludge of gasoline indicates damage to the inner coating of the tank. In this case, it is necessary to fill the tank with 10 ... 15 liters of dehydrated oil heated to 105 ° C, used for the engine of the loader, turn the tank over several times so that a thin layer of oil covers all its walls, and drain the remaining oil. The fuel lines and the strainer of the fuel receiving tube are washed simultaneously with the tank. When preparing the loader for winter operation, it is necessary to disassemble the fuel pump, flush the strainer and valves with clean unleaded gasoline, and check the condition of the diaphragm. If the valves do not fit tightly due to the deposition of resin on them, contamination and loss of elasticity of the springs, the pump housing and its valves must be disassembled and washed. If the valve spring is weakened or broken, replace it. To avoid damage to the parts, do not use metal tools when cleaning them. Resin deposits on valves and sockets can be washed off with acetone or unleaded gasoline. Due to the fact that the exhaust valve wears out much more intensively than the discharge valve, it is advisable to periodically swap them. Dismantle and clean the carburetor, remove resin deposits, wash the carburetor parts with unleaded gasoline or acetone, and then blow the jets and channels in the body with clean compressed air. Check the condition of all gaskets, replace worn gaskets. Due to the fact that the loaders operate on leaded gasoline, before cleaning the carburetor parts, they must be immersed for 10 ... 20 minutes in kerosene or another solvent. Once a year, when disassembling the carburetor, as well as when there are interruptions in the operation of the engine, they check the tightness of the float and shut-off valve, the throughput of the jets, as well as the tightness of the mechanical economizer valve, the tightness of the ball and needle valves of the accelerator pump to their seats, the operation of the throttle drive mechanisms and air dampers, mechanical economizer and accelerator pump and the mobility of the vacuum economizer mechanism. Jamming of shutters and valve rods is not allowed. Cooling system. The engine cooling system, which uses water as the coolant, is flushed twice a year. Water in the cooling system causes corrosion of parts and scale deposits. To prevent the formation of scale and corrosion, antiscale agents are used, which are added to the coolant. Descalers, acting on salts, convert them into easily precipitated compounds (soft sludge) or prevent crystallization and salt deposition. At the same time, anti-scale agents form films on the surface of metals that protect the metal from corrosion. When preparing solutions for 10 liters. water add the following amount of antiscale: trisodium phosphate - from 5 to 20 g or sodium hexametaphosphate (hexamet) - 20 ... 30 mg. To reduce the corrosive effect of water used in the engine cooling system of a loader, it is recommended to add potassium chromine dichromate to it, which reduces the formation of scale and promotes the formation of an oxide film on the metal surface, which protects the metal from corrosion. Chromine is poisonous, in a pulverized state it affects the skin, so before preparing its solution, you need to wear rubber gloves and a gas mask, battery. When preparing the loader for operation in winter, the batteries should be insulated, and when operating loaders in areas with a sharply continental climate, it is necessary to use an electrolyte of a higher density. During maintenance of the battery in winter, it is imperative to check the density of the electrolyte, since at low temperatures the low-density electrolyte may freeze. Relay-regulator. They open the relay-regulator, clean it of dirt and corrosion products, check the sealing gasket, the serviceability of electrical connections, insulation, resistance, fastening and condition of the armature springs, and clean the burnt contacts. To clean the contacts, use abrasive paper with a grit size of M40. After stripping, the contacts must be thoroughly blown out with compressed air and wiped with a clean cloth moistened with unleaded gasoline. It is unacceptable to use abrasive paper with a larger grain size for cleaning contacts. Next, you need to check and, if necessary, adjust the gaps in the relay regulators. Hydraulic drive. Change the working fluid in the hydraulic system of the loader in accordance with the season of operation. To do this, the working fluid present in the hydraulic system is drained into a special container, the high and low pressure pipelines are disconnected from the hydraulic tank, the hydraulic tank is removed, and the filters are removed from it. The outer surface of the hydraulic tank is cleaned of dirt and wiped, the inner surface is washed with kerosene, blown with compressed air and inspected. If there is spot rust on the inner walls of the hydraulic tank, it is necessary to pickle with a 10% hydrochloric acid solution for 10 minutes, then neutralize with a 15 ... 20% solution of carbon dioxide and rinse with hot water for 5 ... 10 minutes. The coarse filter (filler) is washed with kerosene, cleaned with a nylon brush, then washed with unleaded gasoline and dried with compressed air. Unscrew the bolts securing the drain filter housing and remove it from the hydraulic tank housing. The drain filter is washed with kerosene, and the filter elements with clean gasoline, blown with compressed air, the filter parts are inspected, special attention is paid to the filter elements. Tears and holes are not allowed on them. Defective parts must be replaced. After that, the hydraulic tank is assembled and installed in place. Connect the pipelines and fill in a new working fluid corresponding to the season of operation of the loader (winter or summer). Transmission. The oil in the box is replaced with seasonal oil. When changing the oil, the crankcase is washed with liquid mineral oil, the magnetic plugs (loader 4075) and the breather are cleaned of dirt. Refueling systems and mechanisms with fuel, lubricants and working fluids Trouble-free operation of loader mechanisms and systems largely depends on timely and high-quality refueling and lubrication of machines, as well as strict adherence to the operating instructions and the use of recommended grades and grades of fuel, lubricants and working fluid . The operating instructions for each loader include diagrams and tables of lubrication, which indicate the places and number of lubrication points, frequency, brands of lubricant for summer and winter operation, and lubrication method. The reliable operation of the engine largely depends on the strict observance of the rules for refueling and storing fuel. Refueling should be carried out only with settled fuel, which excludes the ingress of foreign particles and water into the engine power supply system. Before refueling, fuel fillers and caps must be free of dust, dirt and fuel residues. Refueling should be carried out, as a rule, through a dispenser or from mobile filling stations. When refueling manually, a clean inventory container and a funnel with a filter should be used. Do not refuel while the engine is running. Fire safety regulations must be strictly observed. The engine, gearbox, reverse gear, drive axle are lubricated with engine and transmission oils poured into the crankcases. The oil is changed immediately after the engine is stopped, while the used oil is in a heated, diluted state and easily flows out through the drain hole. After draining the used oil, the crankcases are filled with diesel fuel and after the units have been idling for 3 ... 5 minutes, the fuel is drained and the crankcase is filled with clean oil. The amount of oil to be filled must strictly comply with the recommendations in the operating instructions. The cardan shaft joints are also lubricated with oil through the grease fittings on the crosspieces. In the loader, most of the mechanisms are lubricated with special lubricants. Due to the ability of the lubricant to stay close to the friction pair for much longer, its consumption is much less than oil. The properties of lubricants are less dependent on temperature, many of them do not lose their ability to protect the metal from dry friction even when water enters. For lubrication, a grease gun is used, which is included in the loader tool kit. Lubrication should be done carefully so that foreign contaminants do not get into the assembly unit or mechanism with the lubricant. Lubricators must be cleaned of dirt and dust before filling them. After washing the loader, it is necessary to re-lubricate all articulated joints, since during washing, part of the lubricant is washed out with water. After lubrication, any escaping lubricant must be removed from all parts to prevent dust and dirt from adhering to it. Lubrication of the machine is carried out during scheduled maintenance of the machine. The hydraulic fluid is replaced during seasonal maintenance. When changing the fluid, the hydraulic system is flushed with kerosene. The hydraulic system is topped up with oil of the same brand. When refueling the hydraulic system, measures are taken to ensure the cleanliness of the refueling facilities, to clean the filler necks and caps from dust and dirt. Loader technical diagnostics The introduction of technical diagnostics into the practice of loader maintenance is one of the most effective measures to improve the reliability of machines and their economical use. Diagnostics makes it possible to reduce the number of repairs and make better use of the resource of machines, reduce downtime due to technical malfunctions, reduce the labor intensity of repair and maintenance by reducing the amount of disassembly and assembly work, and increase technical and operational performance due to timely and high-quality regulation of working units and mechanisms. With the help of technical diagnostics, the technical condition of the units, mechanisms and systems of the loader is established, which makes it possible to determine, without its disassembly, the need for regulation of a particular system, current or major repairs. When the loader is operating, the initial parameters of its individual mechanisms change, for example, there is a loss of engine power, a decrease in the supply of hydraulic pumps and working pressure in the hydraulic system, and gaps in mating parts increase. Therefore, the technical condition of the loader can be established as a combination of these deviations, which manifest themselves in a certain way and are diagnostic parameters. These parameters can be grouped according to common features. Vibration, noise, knocks that appeared in individual units of the machine make it possible to assess the technical condition of the engine, gearbox, drive axle. Clearances, increased applied efforts on the levers and pedals can be used to diagnose steering, brakes, clutch. The technical condition of the loader according to the above parameters is evaluated by various diagnostic methods: mechanical, acoustic, electrical. The mechanical method is based on measuring the dimensions of parts and forces, the noise level is measured by the acoustic method, and the parameters of electrical circuits are measured using the electrical method. Violation of the integrity of metal structures can be checked by electromagnetic, ultrasonic, x-ray methods. The technical condition of the power transmission of the loader is estimated by the value of the total side clearance using a backlash gauge. To measure the clearance, lift one of the drive axle wheels and lock the engine crankshaft. A backlash gauge and a torque wrench are installed on the wheel or axle shaft. Lateral clearance is determined for each gear. To do this, turning off the gear, with a torque wrench, like a lever, turn the wheel in one direction with a certain force, choosing the lateral clearance along the entire kinematic chain to the engine shaft, and set the backlash indicator arrow to zero by turning the housing. Then, by turning the wheel in the opposite direction, the gap is selected and the measurement readings are recorded. The permissible total angular clearance of the gearbox is 4 ... 5 °. Diagnosis of the hydraulic system of the loader is carried out by measuring the pressure using a pressure gauge. As they wear out, the hydraulic pumps reduce the flow and do not develop the pressure indicated in the passport. As a result of wear of parts, fluid leaks in the hydraulic distributor increase, the speed of lifting the load decreases, and when working on heated, low-viscosity oil, the load lifter does not lift the rated load at low and medium engine speeds. Forklift diagnostics are carried out at special posts of mechanization bases or with the help of automobile mobile diagnostic units, which are equipped with a set of instruments and devices for measuring parameters. Rules for the operation of loaders. Basic concepts and definitions Operation is a set of processes for using the machine in accordance with the technical characteristics and ensuring its performance during its service life. Operability - the state of the machine in which it can perform the specified work in accordance with the requirements of technical documentation. Malfunction and failure are malfunctions of the machine. Malfunction - the state of the machine, in which it does not meet at least one of the requirements of the technical documentation. A failure is an event consisting in a violation of the machine's operability. Loader malfunction is caused by production, design, operational reasons. Production causes are failures and malfunctions as a result of a violation of the manufacturing technology, assembly and regulation of parts and assembly units in the manufacturing process, the use of materials with hidden defects. Structural reasons lead to a malfunction due to the wrong choice of mating parts or the type of heat treatment, errors in assigning dimensions and assigning materials to parts. Operational causes of breakdowns and malfunctions occur when the machine is overloaded, control errors, maintenance and repair violations. Maintenance - a set of operations to maintain the performance of the machine, given during its operation (use for its intended purpose, storage, transportation). Repair - a set of operations to restore the performance of machines and their components. The PPR system includes two types of repairs - capital and current. Overhaul is carried out to restore serviceability and fully restore the resource of the machine with the replacement or restoration of any of its parts, including the base ones. Current repair - repair performed to ensure the operability of the machine with the replacement of its individual parts. Maintenance and repair form a system for maintaining the efficiency of the loader in operation. The driver's job The driver's job consists of operating the loader and daily maintenance of it. Management and maintenance are interrelated processes. In the course of work, the driver prepares the loader for work, starts and stops the engine, starts off, controls in motion and when loading and unloading goods. He also does a run-in. Running in. Before the break-in, the machine is depreserved, batteries are charged, parts are lubricated, the power supply and cooling systems of the engine and hydraulic systems are filled, parts are fastened, belt tension is checked, the condition of electrical wires, tires and wheels, and brakes are in good condition. During the running-in process (50 hours), the operation of all machine systems is checked. At the first stage (40% of the total time), the loader is run in without a load, at the second stage (40% of the time) - with a load that is 50% of the nominal, at the last stage (20% of the time) - with a full load. When running in, the following instructions and recommendations must be strictly adhered to. Use fuel, working fluid and lubricants only of those grades recommended by the loader manufacturer. The use of substitutes during the break-in period is prohibited. Do not overload the loader engine. The mass of the lifted and transported load during the break-in period should not exceed 75% of the loader's rated load capacity. In the first hours of operation, it is necessary to check the temperature of the wheel hubs, brake drums, gearbox, reverse gear, front axle final drive, pump drive gearbox and hydraulic tank by touch. If the temperature exceeds 60 ... 70 °C, you should find out the cause of the heating and eliminate the malfunctions. During the break-in period, it is recommended to check and, if necessary, adjust the tension of the engine drive belts. It is also necessary to carefully monitor the condition of all loader fastenings, and after 10 and 25 hours of operation, tighten the nuts of the engine cylinder head fastening studs using a torque wrench. The movement of the loader should be started after the engine has warmed up, and loading and unloading operations - after the working fluid in the hydraulic system has warmed up. When warming up the engine, moving the loader and performing loading and unloading operations with a forklift, do not allow the engine to run at the highest speed. It is necessary to monitor the tightness of all connections of the hydraulic drive and other loader systems. If, when the loader is moving without a load, a large mutual movement of the forklift frames and the carriage is detected, which causes increased play, then it is necessary to adjust the gaps between the side rollers and the forklift frames. If frame misalignment is detected while tilting the forklift forward or backward, adjust the length of the tilt cylinders. During the break-in period, driver training on the loader is not allowed. After 25 hours of operation of the loader, it is necessary to lubricate all the parts indicated in the lubrication chart for TO-1, change the oil in the engine crankcase and drain the sediment from the full-flow filter of the engine lubrication system. After the break-in is completed, daily maintenance and a number of additional operations must be performed. Change the lubricant in the gearbox housings, the reverse gear, the drive axle and in the crankcase of the hydraulic pump drive gearbox, and also replace the working fluid in the loader hydraulic system. Then drain the sediment from the fuel filter sump. Check the adjustment of the front and rear wheel bearings and adjust if necessary. Check the tightness of the engine cylinder head nuts and, if necessary, tighten them. Adjust the carburetor to a low idle speed. Check the electrolyte level, degree of contamination, cleanliness and fastening of the battery. Tighten the battery terminals and lubricate with technical vaseline. Check the gap between the breaker contacts, the ignition setting and, if necessary, adjust the gaps between the valves and pushers of the loader engine. Then lubricate all the parts indicated on the lubrication chart. Starting, warming up and stopping the engine. Ways to start the engine depend on its thermal state and ambient temperature. The use of incorrect starting techniques takes the driver a lot of time and effort and reduces the durability of the engine. There are three cases of starting the engine: starting a warm engine, starting a cold engine at a moderate temperature, and starting a cold engine at a low ambient temperature. Transportation of loaders. Loaders are transported by road under their own power or by vehicles of general or special purpose. It is forbidden to drive under its own power at night on unlit roads for loaders that are not equipped with means of light signaling and lighting. If the height of the vehicle with a loader loaded on it exceeds 4 m, then the route must be agreed with the traffic police. By rail, loaders are transported on platforms, in wagons or gondola cars (depending on the size and weight of the machine). Machines are fixed according to the specifications of the Ministry of Railways. After the loader is installed and fixed on the platform, water and fuel are drained from it, and electrolyte from the storage batteries is also drained in winter. Cabin doors, windows, hood are closed and sealed. . Fundamentals of electrical engineering 4.1. Basic information from electrical engineering Electric current is called the ordered movement of electric charges q in a conducting medium under the influence of an electric field. If the speed of movement of electric charges in time is unchanged, then the current is called constant. The current, the instantaneous values of which change with time, is called variable, the electric current, the instantaneous values of which are repeated at regular intervals, is called periodic variable. A current that changes according to a sinusoidal law is called sinusoidal. The current is expressed in amperes (A) and denoted by I, i. An electric current in a circuit occurs if a potential difference is created at its clamps (poles) (there is an electric field along the circuit section). The potential difference between two points in a circuit is called voltage or voltage drop. Voltage is designated U, u and is expressed in volts (V). The electrical voltage is numerically equal to the work A performed by the source of electrical energy when moving the charge q in one pendant from one point to another. The ability of a conductor to interfere with an electric current passing through it is called resistance. Resistance is denoted by R, r. and expressed in ohms (Ohm). Ohm's law for a complete circuit: I \u003d E / (R + r) Ohm's law for a circuit section: I \u003d U / R .d. A parallel connection of current consumers is such a connection when the beginnings of all pantographs are connected at one point, and the ends at another point. Thermal effect of electric current. All conductors, when an electric current passes through them, heat up and give off heat to the environment. The heating temperature of the conductor depends on the magnitude of the current, the cross section and material of the conductor, and the conditions for its cooling. Joule-Lenz law: Q = I2*R*t (joule) Direct current power Power is the work done per unit time t developed in this section. P = A/t = U*q/t = U*I The unit of power is watt (W). The concept of a magnetic field. A magnetic field is formed around a conductor through which current flows. Magnetic induction lines around a conductor with current have the following properties: - magnetic induction lines of a rectilinear conductor are in the form of concentric circles; - the closer to the conductor, the denser the magnetic induction lines are; - magnetic induction (field intensity) depends on the magnitude of the current in the conductor; - the direction of the magnetic induction lines depends on the direction of the current in the conductor (the gimlet rule). Alternating current. Alternating current has the following characteristics: amplitude, frequency, period. The period of time after which a change in a variable (emf, voltage, current) is repeated is called a period. The period is measured in seconds and is denoted by T. The number of periods per second is called the frequency of the alternating current. The frequency is denoted f and is measured in hertz (Hz). Between the period and frequency there is the following dependence: T = 1/f; f = 1/T AC power. Active, that is, useful power of a single-phase alternating current is determined by the formula: P = U*I*cos j Power factor is the ratio of active power to total power: cos j = P / S The power factor is practically the cosine of the phase angle between current and voltage. The less cos j the consumer has, the less will be the coefficient of performance (efficiency) of the machine, the less active power will be given by the generator. Causes of low power factor: 1. Underloading of AC motors; 2. Wrong choice of motor type; 3. Increased clearance between the rotor and stator; 4. The operation of electric motors at idle. Three-phase alternating current. A three-phase AC system is a system consisting of three AC electrical circuits of the same frequency, which are phase-shifted by 1/3 period (120 °) relative to each other. Connection of the windings of an electrical machine with a star Star connection - the ends of the windings are connected together, and the beginnings of the windings are connected to the line wires. The point at which the ends of the windings are connected is called zero or neutral. The wire connected to it is also called neutral or zero. The potential difference between the linear and neutral wire is called the phase voltage (Uf). The potential difference between two linear wires is called linear voltage (Ul). Dependence between linear and phase voltage: Ul = Ö3 Uf When connected with a star, the linear current is equal to the phase current. Il \u003d If Connection of windings with a triangle. A triangle connection is called a connection when the end of the first winding is connected to the beginning of the second winding, the end of the second winding to the beginning of the third, the end of the third to the beginning of the first winding. When connected by a triangle: Ul \u003d Uf; Il \u003d Ö3 If A transformer is an electromagnetic device designed to convert alternating current of one voltage into alternating current of another voltage of the same frequency. The principle of operation of the transformer is based on the phenomenon of mutual induction. The ratio of the number of turns of the primary winding to the number of turns of the secondary winding or the ratio of the voltage of the primary winding to the voltage of the secondary winding is called the transformation ratio. Rectifiers are used to convert AC to DC. Control questions: What is called electric current? What is the constant current? What current is called alternating? What is called voltage or voltage drop? What is phase voltage? What is line voltage? I. General technical course Section 4. Fundamentals of electrical engineering 4.2. General information about electrical equipment and electric motors General information. Electrical equipment according to its purpose is divided into the main - electric drive equipment and auxiliary - equipment for working and repair lighting, alarm and heating. The main electrical equipment includes: electric motors, magnetic starters, contactors, control relays, devices for regulating the speed of electric motors; brake control devices; electrical and mechanical protection devices; semiconductor rectifiers - AC-to-DC converters for powering the excitation winding of a vortex brake generator or for other purposes; step-down transformers used to power control circuits; devices and devices used to turn on control circuits. Auxiliary electrical equipment includes lighting, heating, signaling, communication and addressing devices. Electric motors. Types and device. Asynchronous electric motors of three-phase alternating current. The following types of motors are used: with a phase and with a squirrel-cage rotor. Motors with a squirrel-cage rotor are single and multi-speed. Single-speed motors are divided into self-braking - with built-in brake and without built-in brake. Rice. 1 Asynchronous electric motor with a squirrel-cage rotor (a) and a phase rotor (b). An asynchronous electric motor (Fig. 1 a) consists of two main parts: a fixed one - a stator 2 and a rotating one - a rotor 5. The stator has a cast-iron or aluminum frame 1 with an active part pressed into it, which is a package assembled from plates of thin sheet electrical steel . Each plate is isolated from the next by a layer of varnish. Longitudinal grooves are made on the inner cylindrical surface of the package, in which the stator winding is located. The winding consists of three coils (or groups of coils) with insulated copper wire, shifted around the circumference of the stator at an equal angle relative to each other. The conclusions from the beginning and end of each of the three groups of stator coils are connected to each other in a box of 3 conclusions located on the outer side of the motor frame. The stator winding of these motors is more often designed to operate at a network voltage of 220 and 380 V. At a voltage of 220 V, the winding is connected by a triangle (Δ) (Fig. 2, a), 380 V - by a star (Υ) (Fig. 2, b). For ease of connection, all six leads from the winding are marked: the beginnings of the coils are marked C1, C2 C3, the ends - C4, Cs, Sat. The frame is closed on both sides with covers 4 (see Fig. 2, a), which are attached to it with bolts or tie rods. The covers contain bearings in which the rotor shaft rotates. Rice. Fig. 2. Schemes for connecting the stator windings of asynchronous electric motors: a - a triangle, b - a star, c - a double star Rotor 5, like the stator, is assembled from insulated sheets of electrical steel. On the outer part of the rotor there are grooves in which the winding fits. According to the type of rotor winding, electric motors are divided into motors with a squirrel-cage and with a phase rotor. In a squirrel-cage rotor, the winding consists of rods laid in grooves and connected from the end sides by conductive rings. Such a winding is called a squirrel wheel. The phase rotor (Fig. 1, b) is distinguished by the fact that the winding 7 from an insulated drive is laid in the grooves of the package 8. Like the stator winding, it consists of three coils or three groups of coils. The beginnings of the coils are connected by a star on the rotor, and the ends are connected to three contact rings 6, isolated from each other and from the rotor shaft. Carbon (graphite) brushes are superimposed on the rings, which are in brush holders, which are mounted on one of the covers of the motor frame. When the brushes are pressed against the slip rings, a sliding current collection occurs, i.e. the rotating winding of the rotor can be electrically connected to fixed resistors outside the motor. The additional resistance of the resistors included in the rotor circuit reduces the starting current of the motor, which reduces its starting torque and ensures a smooth start. The operation of the electric motor is based on the interaction of the rotating magnetic field of the stator winding and the currents induced in the rotor winding. If we take, for example, a steel ring, wind three wire windings (spirals) on it at the same distance along the ring from one another and pass a three-phase current through them, then a magnetic field is formed at each winding. Interacting with each other, these three fields form a common magnetic field; it will remain unchanged in magnitude, and will rotate around the axis of the ring, which is why it is called rotating. In the motor, the rotating stator field crosses the rotor winding with magnetic lines of force, while an electric current arises (induced) in it, which interacts with the stator magnetic field. The force of interaction of the current in the rotor winding with the rotating magnetic field of the stator creates a moment on the rotor axis, under the influence of which the rotor rotates after the stator field, while overcoming the moment of the external load applied to the motor shaft. The frequency of rotation of the stator magnetic field depends on the frequency of the current and the number of pairs of poles. The rotor speed of an induction motor is always slightly less than the speed of the stator magnetic field. Therefore, this type of motor is called asynchronous (not coinciding in time). During engine acceleration, as the rotor speed approaches the speed of the stator magnetic field, the relative speed of crossing the rotor winding by the rotating stator magnetic field decreases, and the current in the rotor decreases, as well as the torque. When the moment of resistance becomes equal to the torque of the engine, a state of equilibrium occurs in which the rotor speed does not change. If a load torque is applied to the motor shaft, directed in the same direction as the motor torque, then the motor shaft speed will increase, reach the magnetic field speed and slightly exceed it. From this moment on, the motor will start to operate in the over-synchronous braking mode, also called generator braking, since the motor, operating in this mode, gives energy to the network. Such a transition from the motor mode to the generator mode occurs at the drive motors of the hoisting mechanism of the hoists. The lifting of the load occurs in the motor mode, and lowering it - in the generator mode. To change the direction of rotation of an induction motor, it is enough to swap any two phases that feed the stator winding. This will change the direction of the current in the motor windings, therefore, the direction of rotation of the magnetic field of the stator and rotor. The frequency of rotation of the stator magnetic field n1 (rpm) is directly proportional to the frequency f of the alternating current and inversely proportional to the number p of pole pairs in the stator winding n1 \u003d (f * 60) / p. Three groups of stator coils, shifted along the stator circumference at an equal angle relative to each other, form one pair of poles, six groups form two pairs of poles, nine - three pairs, etc. Thus, by changing the number of groups of coils in the motor stator, you can change the frequency of rotation of its magnetic field, and hence the motor shaft. In multi-speed motors with six groups of coils or more, by changing the order of connecting them to each other and connecting them to the wires of an external network, the rotor speed is changed. For example, in a two-speed motor with six groups of stator coils, for slow rotation of the rotor they are connected in pairs in series with a triangle, and for fast rotation - with a double star (see Fig. 2, c). The motors have two to four shaft speeds. Now they produce asynchronous motors designed to operate at only one voltage (127, 220 or 380 V); The voltage is indicated on a plate affixed to the outside of the motor frame. Self-braking asynchronous electric motor with built-in brakes (Fig. 3). The rotor of this engine is not cylindrical, but conical in shape, corresponding to the shape of the stator bore 3. When the engine is turned off, the rotor is pushed out of the stator bore in the direction of its axis by the force of the spring 6, forming an increased gap. In this case, the braking cone 5, rigidly connected to the rotor shaft, is pressed against the conical surface located inside the cover 4 of the electric motor. Therefore, the switched off engine is in the inhibited state. The braking force is regulated by pre-tightening the spring 5 with the nuts 7. When the electric motor is turned on, the rotor is drawn into the stator bore until the shaft thickening stops against the bearing 8. The gap between the rotor and the stator is then reduced to a normal value, the spring 6 is compressed, the brake cone moves away from the conical surface cover of the electric motor and braking stops - the electric motor is running. Rice. 3 Self-braking electric motor 1.8 - bearings, 2 - rotor, 3 - stator, 4 - cover, 5 - braking cone, 6 - spring, 7 - adjusting nuts Motor operating modes are divided into short-term and intermittent. Short-term is such a mode in which the electric motor is turned on for a short time (10 ... 20 minutes), and at the same time does not have time to heat up to a steady temperature. Then comes a long break in operation until the engine cools down completely. Repeated-short-term mode is a long-term repeating cycles. In each cycle, switching on - work, switching off - pause sequentially alternate. This mode is characterized by the on-time (PV), expressed as a percentage: PV-(working time / cycle time) - 100%. The cycle time in this mode should not exceed 10 minutes. Thus, if the engine runs continuously for 10 minutes, then the duty cycle is 100%. Standard values are 15%, 25%, 40% and 60% duty cycle. For example, the cycle time of the electric motor of the hoist lifting mechanism is the sum of the engine operating time when lifting the load to a given floor, the break time required to unload the load on a given floor, the time for lowering the load-carrying body to its original position to take a new portion of the load, the loading time of the load-carrying body lift and preparatory-final time, consisting of relatively short breaks between the listed operations. Exceeding the PV during operation of the engine leads to its overheating, which can disrupt the insulation of the winding wire of its coils. Apparatus for infrequent switching, closing and opening of electrical circuits Knife switches, power cabinets. Knife switches and power cabinets are used for infrequent switching of electrical consumers of alternating or direct current with a voltage of up to 500 V and are mainly used to connect lifts to an external network. The knife switch (Fig. 4 a) has one or more movable knives 1, hinged in contact racks 6. The knives are connected by a traverse 3 made of insulating material. When the knife switch is turned on, the knives are inserted into contact jaws 2. Wires from the external network are connected to the jaws, and wires or cable strands leading to the lift are connected to the contact racks of the knives. The knife switch is controlled (turned on and off) using handle 4. The knife switch must be covered with a casing. At a knife switch designed to turn off high currents, the handle is often located on the side and is connected to the knives through a lever system. The power cabinet (Fig. 4 b) is made of sheet metal. The following are mounted on an insulating plate in this cabinet: knife switch 8, its control mechanism using the side handle 9 and fuses 10. The handle has a locking device, thanks to which it is impossible to open the cabinet door when the switch is on and turn on the switch when the cabinet is open. Spring-loaded holders for spare fuses are usually installed on the inside of the cabinet door. For safe operation, cabinet 7 and the switch housing are grounded. Rice. 4 Apparatus for infrequent switching: a - knife switch, b - power cabinet 1 - knife, 2 - contact jaws, 3 - traverse, 4, 9 - handles, 5 - insulating plate, 6 - contact rack, 7 - cabinet, 8 - built-in knife switch, 10 - fuses, 11 - ground clamp, 12 - spare fuses Circuit breakers. Automatic switches (automatic devices) are designed to automatically turn off electrical circuits in case of violation of normal operating conditions (for example, during overload or short circuit), as well as for infrequent switching on or off of electrical circuits. The circuit breaker (Fig. 5, a) consists of a base with a cover, a switching device, arc chutes, a control mechanism and overcurrent releases. All parts of the machine are mounted on the plastic base 1 under the cover 2. The switching device includes fixed 3 and 4 moving contacts. The fixed contacts are fixed on the base, and the movable ones - on a common insulating traverse 5. The arc chutes 18, located above the contacts of each pole, have two cheeks made of insulating material and several metal plates fixed between the cheeks. Rice. 5 Circuit breaker (a) and positions (b, c) of the lever system: b - open, c - closed 1 - base, 2 - cover, 3, 4 - contacts, 5 - traverse, 9, - levers, 7 - handle, 8, 10 - springs, 12 - thrust, 14 - thermoelement, 15 - armature, 16 - coil, 17 - screw, 18 - arc chute The control mechanism consists of a lever system, working and auxiliary springs and a drive handle is determined by the position of the handle: in the on position it occupies the extreme upper position, in the off position it occupies the extreme lower position, in the disconnected release it is in the middle position. On fig. and the machine is shown in the open position after the overcurrent release has tripped. To prepare the machine for switching on, the handle 7 is moved down so that the curly lever 6 turns and engages with the tooth of the lever 11 with its lower end. The position of the lever system of the control mechanism for this state is shown in fig. b. To turn on the machine, its handle is moved to the highest position. In this case, the direction of action of the spring 8 changes. The levers 9 rotate relative to each other, move upward from the middle position (Fig. 5 b) and close the contacts 5 and 4 of the machine. The machine is switched off when the overcurrent release trips. According to the principle of operation, the releases are: thermal, electromagnetic and combined, consisting of series-connected thermal and electromagnetic releases. The thermal release consists of a thermoelement 14 and a bimetallic plate 13, which bends when heated (the plate is heated by the thermoelement if an overload current passes through it). When the plate is bent, its free end moves down and, overcoming the force of the spring 10, rotates the lever 11 through the rod 12. The tooth of the lever disengages from the curly lever 6. Under the action of the spring 8, the curly lever rotates around its axis at a certain angle and changes the position of the levers 9 . In this case, the machine is turned off with a time delay that is inversely related to the current strength. Therefore, the greater the current, the less time it takes to turn off the machine. The electromagnetic release consists of coil 16 and armature /5. When a short circuit current occurs, the core is instantly drawn into the coil. In this case, the lever 11 turns, releases the figured lever from engagement with the tooth, and the machine switches off without delay. Automata are included in the power line from the external network to protect against overload and short circuit currents, and sometimes automata are also used to protect control circuits. Contactors and magnetic starters. A contactor is an electrical device for closing and opening electrical circuits, driven by an electromagnet. Depending on the type of current, there are direct and alternating current contactors. According to the number of simultaneously switched circuits, contactors are divided into single- and multi-pole. A three-pole AC contactor (fig. 6) consists of three main parts: a magnetic system, a main contact system and an auxiliary contact system. The magnetic system includes a fixed part - yoke 1, coil 2 and a moving part - armature 3. The yoke and armature of the AC contactors are riveted from thin electrical steel plates. The main contact system consists of 9 fixed and 10 moving contacts, to which the wires of the switched circuit are connected. Moving contacts are mounted on the same shaft with the armature. Auxiliary contacts 6 and 7, also connected to the armature shaft, are used for electrical switching in control circuits in which the contactor coil is included. The main contacts are made massive, designed for high current, and the auxiliary contacts are made small, since the current in the control circuit usually does not exceed 5A. Rice. 6 Three-pole AC contactor: 1 - yoke, 2 - coil, 3 - armature, 4 - shaft, 5 - moving contact connection, 6, 7 - auxiliary contacts, 8 - arc chute, 9, 10 - contacts, 11 - short - closed loop, 12 - spring When the contactor coil is connected to the network with the corresponding voltage, a magnetic flux occurs in the magnetic system of the contactor. Under the influence of this flow, the anchor is attracted to the yoke. The shaft 4 rotates together with the armature, and the movable contacts 10 mounted on it are connected to the corresponding fixed contacts 9. Springs are installed on the levers of the movable contacts, which provide a uniform pressure density of one contact to another. Simultaneously with the power contacts, auxiliary contacts 7 close and auxiliary contacts 6 open. When the coil is disconnected from the network, the magnetic flux disappears, the armature falls off the yoke under the action of the contact springs and its own gravity, the power contacts and auxiliary contacts 7 close, and the block contacts 6 open. Therefore, block contacts 6 are called break contacts, and block contacts 7 are called make contacts. When electrical circuits are opened under load, an electric arc occurs between the power contacts, the power of which depends on the voltage, type of current and its magnitude. An electric arc, even briefly formed between the contacts, causes their wear, burning and destruction. To reduce the time of burning the arc, deionic or electromagnetic forced extinguishing of the arc is used. In both cases, the power contacts are enclosed in an arc chute 8 made of a heat-resistant material. The chamber serves to cool and extinguish the arc, and also prevents it from being transferred to adjacent devices or grounded parts. The operation of the contactor with the arc chutes removed is not allowed. If the power of the contacts is small, then forced extinguishing of the arc is not used, but between the poles of the contactor, that is, between pairs of contacts, partitions are placed to prevent the arc from being transferred to the contacts of adjacent poles. The current in the alternating current coil drops to zero 100 times within a second (at a frequency of 50 Hz), and the traction force of the electromagnet decreases accordingly. At this point, the armature may move away from the yoke somewhat, so the contactor electromagnet will work with vibration and hum. To eliminate these phenomena, short-circuited turns 11 are put on the ends of the yoke and armature, due to which the magnetic flux does not decrease to zero. With serviceable short-circuited coils, the magnetic system of the contactor works with a slight buzz, without noticeable vibration. A magnetic starter is a small-sized contactor of a simplified design, designed for a smaller number of inclusions and a lower current. Unlike a contactor, it can have a built-in thermal release that protects the motor from damage during overload. Magnetic starters are mainly used to control squirrel-cage motors on cargo lifts. Devices of protection of electric equipment Intermediate relay. An intermediate relay is used as an auxiliary device when the main device does not have a sufficient number of contacts, the main device is not enough to open or close the circuit. Intermediate relays (Fig. 7) are produced with DC and AC coils. Such relays have from three to six contacts 1. The movable contacts of the relay - bridge type - are mounted on the same rod with an armature 2. When the coil 4, located on the yoke of the magnetic system of the relay, is connected to the network, the armature is attracted to the yoke and the contacts work, i.e. e. they close or open the fixed contacts located on the relay case, while performing the necessary switching in the circuit. Relay contacts are designed for current up to 20 A. Fig. 7 Intermediate relay: 1 - contacts, 2 - armature, 3 - yoke, 4 - coil, 5 - bracket Time relay. The time relay is used for automatic closing and opening of control circuits with a given time delay. The electromagnetic system of the relay is designed in such a way that when the relay coil is connected to the network, the relay armature is attracted to the yoke, and when the coil is turned off, it is automatically short-circuited and the magnetic flux in the relay magnetic system, which persists for a while, keeps the armature in an attracted state. After the weakening of the magnetic flux, the return spring breaks the armature from the yoke and opens the switching contacts. The time during which the armature is in a state attracted to the yoke after the coil is disconnected from the network is called the exposure time. This time depends on the type of relay, its adjustment and is in the range of 0.2 ... 3 s. Maximum relay. The maximum relay, or maximum current relay (Fig. 8), serves to protect the electric motor from damage when it is overloaded or short circuited. The relay is set up like this. A coil 5 of thick insulated wire is put on the outside of a vertically located brass tube 2, and inside the tube, in its lower part, there is a steel cylindrical rod (armature) 4. The relay coil is connected in series to the phase of the motor circuit. When current flows through the coil, a magnetic field is created that increases with increasing current. Rice. 8 Maximum relay: 1 - rod, 2 - tube, 3 - bracket, 9 - insulating block, 10 - contacts, 11 - rocker arm, 12 - axle, 13 - spring pointer: the lower the rod (anchor) in the brass tube, the more current is needed to operate the relay. dependent on the current in the circuit Thermal relay. The thermal relay serves to protect the electric motor from small, but long-term overloads, at which the motor current is 10 ... 20% higher than the rated one. The relay is activated at a certain temperature, the engine. Rice. 9 Thermal relay: 3 - lever, 4 - spring, 5 - contacts, 6 - bimetallic plate In lifts, bimetallic thermal relays are used (Fig. 9). The main element of the relay is a bimetallic plate b, consisting of two metals with different coefficients of linear expansion. When the plate is heated by a working current passing through the heating element / located next to it, it bends towards the metal with a lower temperature coefficient of linear expansion. The end of the plate, rising, releases the lever 3, which under the action of the spring 4 turns counterclockwise. The rod connected to the lever opens the relay contacts, as a result of which the contactor or magnetic starter is turned off, with the help of which the engine was connected to the network. The relay is returned to its original position manually by pressing the return device 2 after the bimetallic plate has cooled down for 60...90 s. The relay operates with a time delay that is inversely related to the current strength; the greater the current in the heater, the less time is required to heat the bimetallic plate, and, consequently, to operate the relay. Fuses. Fuses are designed to protect electrical equipment and electrical networks from high currents that can damage them. These currents can occur during short circuits and significant overloads (by 50% or more). The main working element of fuses is a conductor, usually of a low melting point and of a certain cross-sectional area. The current of the protected circuit passes through this conductor. When the current in the circuit increases, the conductor is heated by this current, melts and opens the protected circuit. Tubular fuses are used to protect the power circuits of electric motors, and plug (threaded) fuses are used for lighting and signaling circuits. A tubular fuse consists of a cartridge (tube) with contact tips fixed at its ends in the form of caps or knives, to which the ends of a fusible calibrated conductor located inside the cartridge are attached. When installing a fuse, its contact tips are included in the spring clips of the safety shield. Fuse holders are made of fibre, porcelain or glass. During the melting of the calibrated conductor in the cartridge, the fiber partially decomposes, the resulting gases have an arc-extinguishing property. Cartridges made of other materials are filled with dry quartz sand for the same purpose. Cork fuses also have a fusible conductor of a certain cross section, but it is located in the channel of the porcelain fuse body, which ends with a threaded part (base) and end contact. One end of the fusible conductor is tightly connected (welded or soldered) to the threaded part of the base, and the other to its end contact. Cork fuses are screwed into the threaded socket of the safety block. In this case, the end contact of the fuse must be tightly adjacent to the contact located deep in the socket. With a loose connection between the contacts, sparking occurs and, as a result, heating, the contacts are oxidized and, in some cases, the electrical circuit is broken. Blown fuses are replaced with new ones with a fuse-link designed for the same current. Limit switches. Limit switches are mainly used to limit the operation of mechanisms, in some cases they are used as interlock switches or to turn on alarm circuits or address cargo. Limit switches according to the principle of their operation are divided into two groups. The first group includes switches that require mechanical (force) action for their operation, the second group - those that do not require mechanical action for operation. Of the switches of the first group, lever ones are mainly used. Limit switch of the VP-16 series, most often used as a limit or limit switch on construction cargo and passenger-and-freight hoists. The switch consists of a metal case with a sealed cover. The body inside is divided into two compartments, one of them contains the contact block, and the other - the instant action mechanism. At the location of this mechanism there is a drive roller, at the outer end of which a lever with a roller is fixed. At the inner end of the roller there is a leash in the form of a spring-loaded tooth, which, when the roller is turned, acts on the contact system of the switch in such a way that some of its contacts instantly close, while others also instantly open. The action of the contacts is provided by a spring mechanism located in the switch housing. When the load is removed from the roller, it returns with the help of selective springs of the switch. Lever limit switch type VK-300. The contact system of the switch is located in the housing under a sealed cover. The lever with the roller of this switch can be set to different initial positions by moving it on the splines of the axis. For mechanical action on the limit switch lever through the roller, a ski is usually used, which, moving, deflects the lever. Non-contact HPC sensors and sensors with sealed contacts - reed switches are used as switches of the second group. Manual control devices. To control electric motors, control buttons and push-button stations, conventional and package switches, universal switches are used. The control buttons are used to close and open the circuits that feed the coils of contactors, magnetic starters and relays, as well as to turn on the sound signal. The button consists of a rod with a head (pusher) mounted on the rod of the contact bridge, and fixed contacts mounted on the button body. The pusher is held in its original position by a return spring. Buttons usually have make and break contacts that are not electrically connected to each other. Button contacts can withstand current up to 5 A. Button pushers are often labeled Start or Stop. Stop buttons are usually red. A set of buttons built into a common casing is called a push-button station, or push-button post. On cargo lifts, portable push-button stations with a plastic casing are more often used. A current of no more than 220 V is supplied to the buttons. The casing of the buttons, if it is metal, is grounded. Batch switches are used to turn on control circuits, lighting and heating devices. Batch switches consist of two main parts: a contact system and a switching mechanism. The contact system is recruited from sections. Each section is an insulator, in the grooves of which there are fixed contacts with clamps for connecting wires. Movable contacts of the switch - sliding. Sections (up to seven) are combined into a package and fixed between the base plate and the switch cover with tie rods. The package switch is turned on and off by turning the central rod by the handle. Thanks to a winding spring device, the switching mechanism provides instantaneous opening and closing of contacts regardless of the speed of rotation of the handle, which reduces sparking in the closing contacts and increases their service life. Control questions: 1. What is the main electrical equipment? 2. What electrical equipment is additional? 3. What is an intermediate relay used for? 4. What are limit switches used for? 5. What is the time relay used for? 6. What is the purpose of a contactor? 7. What is the maximum relay used for? 8. What is a thermal relay used for? 9. What are the control buttons for? 10. What are fuses used for?
The SST company performs service maintenance of loaders in Moscow. These vehicles are complex units, the functioning of which depends on the stability of a large number of components and mechanisms. To ensure their uninterrupted operation, timely service is required, which can only be provided by experienced and professional specialists.
| TO-2 (200 m/h), TO-semi-annual (1200 m/h), TO-annual (2400 m/h) | 200m/h | 1200m/h | 2400m/h | |
| List of performed works | ||||
| 1 | Checking and, if necessary, adjusting valve clearances | x | x | |
| 2 | x | |||
| 3 | Replacing the coolant in the radiator, checking the radiator cap, cooling system hoses, for damage to the radiator | x | ||
| 4 | Replacing the air filter element | x | x | x |
| 5 | Fuel filter replacement | x | x | x |
| 6 | Blowing out the air filter housing, the outer surface of the radiator, the engine compartment | x | x | x |
| 7 | Checking and, if necessary, adjusting the engine idle speed | x | x | x |
| 8 | Check of a condition and adjustment of a tension of a belt of the fan and (or) the generator | x | x | x |
| 9 | Checking and, if necessary, adjusting the tension of the forklift chains, lubricating the chains, lubricating the forklift frames | x | x | x |
| 10 | Changing the oil and filter in the GDP, checking the operation of the GDP distributor, checking the slow-stroke valve of the GDP, inspecting for leaks | x | ||
| 11 | Changing the oil in the GDP, checking the operation of the GDP distributor, checking the slow-stroke valve of the GDP, inspecting for leaks | x | ||
| 12 | Checking the condition of the wheels, checking the backlash, if necessary, adjusting, in the wheel bearings, pulling the wheel fasteners | x | x | x |
| 13 | Checking the serviceability of the steering, adjustment (if possible without replacing the controls), checking the condition of the pivot and ball joints | x | x | x |
| 14 | Lubrication of components and parts through grease fittings | x | x | x |
| 15 | Checking and, if necessary, adjusting the free play of the brake pedal, hand brake; checking the effectiveness of the working and parking brake system; checking the tightness of the working brake system | x | x | |
| 16 | Replacing the brake fluid, checking and, if necessary, adjusting the free play of the brake pedal, hand brake; checking the effectiveness of the working and parking brake system; checking the tightness of the working brake system | x | ||
| 17 | Checking and broaching the fastening of the lift and tilt cylinders, inspecting for leaks | x | x | x |
| 18 | Checking the operation of the hydraulic distributor and its drive, inspecting for leaks | x | x | x |
| 19 | Checking the operation of the hydraulic system pump, inspection for leaks | x | x | x |
| 20 | Changing the oil in the hydraulic system tank with changing the oil filter | x | ||
| 21 | Changing the oil in the hydraulic tank | x | ||
| 22 | Checking and, if necessary, broaching of the connections of the high-pressure hoses of the hydraulic system | x | x | x |
| 23 | Checking the level and density of the electrolyte in the battery, the condition of the battery terminals, cleaning and lubricating them if necessary | x | x | x |
| 24 | Changing the oil in the crankcase or drive axle gearboxes, checking for oil leaks | x | ||
| 25 | Checking the level and quality of oil in the crankcase or drive axle gearboxes, checking for oil leaks | x | ||
| 26 | Replacing spark plugs | x | x | x |
| 27 | Checking and, if necessary, adjusting the ignition timing, checking the condition of the breaker cover, distributor slider | x | x | x |
| The cost of work | from 4000 | from 5500 | from 8000 | |
| materials | ||||
| 1 | Oil filter GDP | 280 | ||
| 2 | Engine oil filter | 470 | 470 | 470 |
| 3 | Fuel filter | 535 | 535 | 535 |
| 4 | Hydraulic return filter | 1470 | ||
| 5 | Air filter element | 545 | 545 | 545 |
| 6 | Motor oil semi-synthetic 8 l. | 2940 | 2940 | 2940 |
| 7 | Washing oil 7l. | 900 | 900 | 900 |
| 8 | Oil for GDP ATF Dexron-III 8 l. | 2940 | 2940 | |
| 9 | Oil hydraulic HLP 32 4 l. | 6400 | 6400 | |
| 10 | Antifreeze WEGO G11 (green) 10 kg | 1110 | ||
| 11 | Grease "Elite-X" EP2 tube cartridge | 400 | 400 | 400 |
| 12 | Brake fluid LUXE DOT-4 0.5 l | 120 | ||
| 13 | Chain and open gear lubricant 200 | 590 | 590 | 590 |
| 14 | Transmission oil GL-5-5l. | 1200 | ||
| The cost of consumables | 6380 | 15720 | 19900 | |
| x - replacement, check (if necessary) | ||||
| The cost of a 2.5 ton machine is increased by 755 rubles. | ||||
Maintenance Features
Like any piece of equipment, a forklift can fail. This happens either due to wear of parts, or due to improper operation, or due to lack of repair. To prevent overhaul expenses, we advise you to carry out maintenance of forklifts in a timely manner. As part of maintenance, a number of activities are carried out, the task of which is to maintain the efficiency of warehouse equipment. Our service specialists can perform diagnostics both in our workshop and directly at your facility. Regular maintenance of components and mechanisms is a guarantee that the equipment will last much longer.
When to carry out maintenance
For maintenance of forklifts, prices in our service start from 4000 rubles. The final cost depends on what range of work was performed in relation to a particular loader. In any case, the machines should be put into maintenance with a certain frequency, which will increase its operational life and functionality:
- at the end of each working day, an inspection of the equipment is required;
- TO-1 is carried out after the operation of the equipment for 100 hours or more. Technical fluids can be replaced, nodes can be lubricated, all mechanisms can be adjusted;
- TO-2 is carried out after the operation of the forklift for 250-300 hours. Within this scope, work is carried out in accordance with TO-1, fuel and air filters are additionally changed;
- regular seasonal maintenance of loaders involves the performance of work on TO-2, as well as an additional oil change in the gearbox and hydraulic system;
- annual maintenance of loaders involves, first of all, the replacement of technical fluids and lubricants.
In each case, the cost of maintenance work varies. Our service center is equipped with everything you need. We service loaders of different brands: Komatsu, Toyota, Nissan, Mitsubishi, Yale, TCM.
Why it is important to perform maintenance on time
Special equipment is able to withstand a high level of load. However, it is very important to carry out timely maintenance and repair so that the units are in working condition. When performing maintenance, problems with the engine, transmission, pump drives or final drive can be immediately identified and prevented from developing into more serious problems. It is almost impossible to carry out maintenance of loaders on your own, therefore it is easier and more reliable to contact a specialized center. The advantages of this solution are obvious:
- diagnostics of equipment will be carried out on special equipment, after which its condition is determined;
- problems related to the technical side are identified in a timely and professional manner;
- only on the equipment can the functions of the forklift be configured;
- as part of the inspection, technical fluids and consumables are replaced;
- if any malfunctions are suddenly found, then repairs are carried out and components are changed.
In addition, only in the service center you can get advice from experienced specialists.
How we are working
The specialists of our service center will perform maintenance of loaders of domestic and foreign production. All works are carried out on professional equipment, so we cope with repair work of any complexity. If necessary, we can conclude a contract with you for the maintenance of forklifts, front loaders. Turning to us, you get the following benefits:
- in our warehouse there is always a large selection of spare parts and consumables, so we eliminate breakdowns as quickly as possible;
- our staff are qualified specialists who have been working in this field for more than 10 years;
- in our work we use specialized tools and equipment;
- you can contact us in any emergency situations, warranty or non-warranty.
To find out what the prices for maintenance of a forklift will be, call our service center. We will perform a thorough diagnosis, after which we will select options for solving problems if they are identified. We perform scheduled and urgent maintenance - call and ask for details!
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Port handling machines
Maintenance and forklift repair concept
The design of the forklifts is characterized by the use of typical automotive components, low voltage direct current electrical equipment and positive displacement hydraulic drives.
The maintenance and repair of the running gear and the power mechanical transmission of loaders in terms of the scope of work and the technology for their implementation are close to the corresponding work on cars.
Breaking in loaders. The service life of a forklift largely depends on the strict observance of the rules of the break-in period after receiving the loader from the manufacturer. Running-in is carried out in order to check the operation of all components and systems of the machine, as well as for better running-in of rubbing parts. During the run-in of forklifts, the internal combustion engine is also run-in, and during the run-in of electric forklifts, training charge-discharge cycles of the battery are performed.
Before starting the break-in, you should try out the working movements of the loader without a work load. During the break-in period, especially during the first trips, they carefully monitor the operation of all components and mechanisms, checking the condition of the fasteners, the tightness of the systems, the smoothness and noiselessness of operation, heating. The running-in duration of a new loader is at least 50 hours, and its rated load capacity should be used during this period by no more than 50-75%.
Forklift maintenance. It is produced in the forms of current (daily) and preventive (periodic) maintenance.
The current (daily) maintenance of loaders in terms of scope and range of work is usually divided into shifts (before starting work) and weekly, that is, after about 50 working hours. Periodic maintenance of these machines is carried out after 200-250 working hours, i.e. almost monthly.
Every shift maintenance includes work on washing and cleaning the machine, checking the condition and operation of the steering, brakes, hydraulic drive, internal combustion engine; checking (charging or changing) traction batteries; refueling the car.
During weekly maintenance, a thorough check and tightening of all fasteners, especially bolts, is carried out, since the drive (front) axle of loaders is not sprung and these connections weaken to a greater extent than for transport vehicles with spring suspension. The following are also performed: checking the condition of pipelines and high-pressure hoses, tightening seals; checking the condition of the bearings of the forklift carriage, springs and parts of the balancing suspension; adding oil to the drive axle gearboxes; checking the condition of the wiring; listening to the engine; sludge drain and filter cleaning.
Preventive (monthly) maintenance is timed to the next weekly maintenance and consists, in addition to weekly work, mainly in inspection and adjustment work.
On electric forklifts with this frequency, tightening of contact connections, cleaning of contact surfaces of contactors, checking the magnitude of pressing and dropping of contactors, cleaning contact segments and fingers of controllers, checking the condition of collectors of electric motors. The condition and value of the insulation resistance is also checked.
During weekly and monthly maintenance of loaders, in addition to the basic mandatory work listed above, “on demand” work is usually performed, including the replacement of wearing parts and minor repairs.
Loaders are lubricated in accordance with factory instructions and lubrication charts.
For carburettor internal combustion engines of forklifts, in addition to performing work on shift maintenance, periodic technical maintenance is performed at intervals of 50, 100 and 1000 working hours.
Chassis. Wear of wheels and steering and cases of breakage of loader springs largely depend on the condition of coatings of storage areas, roads and crossings over railways and crane tracks.
Worn-out trucks are usually not repaired in an operational environment. Metal wheel tires are rubberized at the factories of rubber products.
Adjustment of roller tapered bearings of wheel hubs is carried out according to the general rules for adjusting such units. After adjusting the bearings, during the first hours of operation of the loader, the temperature of the wheel hubs is monitored. If the hubs become hot, the adjustment should be repeated.
The springs of the rear balancing suspension of the steered wheels often fail. Depending on local conditions and the nature of the damage, they are replaced as a set or repaired by replacing individual sheets.
Steering. Steering adjustment is to eliminate the backlash and gaps formed in the steering rod joints and the engagement of the steering mechanism. The play in the hinges of the rods is eliminated by tightening the moving crackers. The steering mechanism is adjusted by sampling the gaps in its engagement. Typical for electric forklifts is the gearing of the steering mechanism, for forklifts - worm gear.
For a worm steering gear, the engagement of the roller and the worm is adjusted by removing or adding the required number of shims to change the size a. In this case, the bipod rod must be disconnected, and the bipod shaft is set in the middle position. In addition, the axial play of the worm tapered bearings is regulated by means of gaskets. After these adjustments, the force required to turn the steering gear should be in the range of 1.5-2.5 kg, and the angle of rotation of the bipod from the middle position in each direction should be at least 42 °.
Rice. 1. Gear steering mechanism
The steering system of forklift trucks with a carrying capacity of 3t more commonly includes hydraulic boosters that reduce the force on the steering wheel. The amplifier is a hydraulic follow-up mechanism in which a spool device (leading link) and a hydraulic power cylinder (slave link) are combined.
The hydraulic booster with a collapsible cylinder is shown in fig. 3. The steel tube of the power cylinder is located between the body and the cover. The body and cover are pulled together with studs and connected by a branch pipe. The body houses the spool mechanism for controlling the power cylinder. The head of the rod through the ball pin is attached to the console welded to the frame of the loader chassis, and the lug of the power cylinder is attached through the rod to the steering linkage lever. The ball pin is connected to the rod of the bipod of the steering mechanism. The spool device consists of a sleeve fixed motionless in the body, and a spool, the shank of which is connected to a ball pin clamped between two crackers in a sliding glass by a rigid spring. Overcoming the resistance of the spring, the ball pin can move along the axis of the cylinder together with the sliding glass by a small amount (2-3 mm) from its middle position. In this case, the spool will move relative to the sleeve by the same amount and in the same direction. Moving, the spool connects the cavities of the power cylinder with the discharge and drain channels so that the movement of the cylinder relative to the piston occurs in the same direction as the displacement of the spool. In the neutral position, the spool is held by a spring. In this case, the oil pumped by the pump has a free passage to the drain.
Rice. 2. Worm gear steering mechanism
Rice. 3. Hydraulic power steering
The position of the hydraulic booster in the steering kinematic circuit is shown in fig. 5. The moment created by the driver on the steering column is converted by the steering mechanism and bipod into a force acting through the rod on the hydraulic booster spool and moving it.
When the steering wheel is turned, for example, to the left, the bipod rod with the ball pin, and with it the spool, will move forward, connecting the channel of the front (left in Fig. 3) cavity of the cylinder with the discharge line, and the channel located on the other side of the piston with drain line. The oil pressure moves the cylinder following the spool to turn the loader wheels. A similar picture will be when the steering wheel is turned to the right.
As soon as the movement of the steering wheel stops, the spool will stop and the cylinder, having caught up with it, will put the sleeve relative to the spool in a neutral position, therefore, the rotation of the steered wheels will stop. Thus, the hydraulic booster cylinder “follows” the movements of the spool all the time and exactly repeats them. The movement of the cylinder is transmitted through the rod to the steering linkage lever, due to which the wheels turn.
To protect the steering hydraulic drive from overload, a safety valve is used, usually mounted in the hydraulic booster spool housing. The operation of the valve is to drain oil into the drain line when the pressure rises above the allowable one.
Rice. 4. Scheme of steering with hydraulic booster (steering column and bipod conventionally depicted in a horizontal plane)
Inspection, adjustment of the safety valve and replacement of its spring can be done without removing the hydraulic booster from the lift truck. The valve is adjusted (on lift trucks 4043 and 4045) for a maximum pressure of 50 kg / cm2 at 1600-2000 rpm of the engine crankshaft and an oil temperature of 30-50 ° C.
Care of the hydraulic booster consists in lubricating the ball pins, periodically checking the cleanliness of the rod and external oil leaks through the joints and seals. A normally working hydraulic booster should provide a steering wheel force of no more than 2-3 kg, regardless of road conditions.
In the event of a malfunction of the hydraulic steering drive (malfunction of the hydraulic pump, breakage of the safety valve spring, etc.), as well as when the forklift engine is not running, the ability to control the machine remains. In this case, the rods act as links in the kinematic steering chain, transmitting force from the steering wheel to the steered wheels of the machine, and the oil flows from one cavity of the booster cylinder to another through the emergency ball valve.
Brakes. Loaders have operational hydraulic brakes driven by a pedal only on the front (driving) wheels. Forklift trucks also have a manual holding brake mounted on the flange of the output shaft of the gearbox. For electric forklifts, an operational brake is used as a holding brake, for which its pedal is equipped with a latch.
Adjustment of hydraulic brakes is carried out as the friction linings on the shoes wear out, when the gaps between the linings and the brake drums increase, which also increases the brake pedal travel. In addition, if necessary, the free play of the brake pedal is adjusted.
The clearance between the shoes and the brake drum is adjusted by turning the eccentric supports of the shoes. It is necessary to pay attention to the uniformity of the adjustment of all blocks and to make adjustments on unheated drums. If adjustment by turning the eccentric pad supports does not give a satisfactory result, the brake pads (or just the brake linings) are replaced. Such a replacement is usually carried out when turning brake drums. In these cases, the initial installation of the pads should be done on the probe. The gap between the pad lining and the drum should be within 0.15-0.25 mm.
The free play of the brake pedal is adjusted by changing the length of the piston pusher of the main brake cylinder so that the gap between the pusher and the piston is 2-3 mm, which corresponds to a pedal free play of 10-15 mm. Adjusting the free play of the brake pedal is necessary to prevent spontaneous braking of the loader while driving.
If air enters the brake system, the normal operation of the brakes is disrupted. Due to the compressibility of the air, the brake pedal springs and its travel increases. Air is removed from the brake system by pumping it with brake fluid using the master brake cylinder. The wheel brakes are bled one by one.
A general indicator of the technical condition of the hydraulic brakes of loaders can be the pedal travel, which, when pressed with your foot until full braking, should be about half of the full travel.
Hydraulic drive. Raising the carriage and tilting the frame of the forklift, as well as the movement of load-handling and auxiliary devices of the loaders, are usually carried out using a volumetric hydraulic drive.
Below, only specific issues of the technical operation of the hydraulic drive of loaders are considered and specified.
The operational adjustments of the hydraulic system of loaders include the adjustment of safety and overflow valves of hydraulic distributors. The hydraulic distributors having both one of these valves, and both are applied.
The safety valve of the hydraulic distributor limits the value of the maximum, and the overflow value of the working pressure of the oil entering the cylinders, and, consequently, the force developed by them. The safety valve is usually regulated by 110-115%, and the overflow valve by 95-100% of the operating pressure of the pump. After adjustment, the valves must be sealed.
Rice. 5. Contacts for turning on the pump motor
In the latter case, a tee with a pressure gauge is installed in the pressure line in front of the distributor, after which the pump is started and the forklift forks are raised to failure (or the frame is tilted to any extreme position). In this case, all the oil supplied by the pump will flow through the valve and it can be adjusted to the required pressure according to the pressure gauge. (If the hydraulic distributor has both valves, then the safety valve is adjusted first with the overflow blocked, and then the overflow.)
For electric forklifts, the moments of turning on the hydraulic pump electric motor are periodically adjusted. Signs of the need for such adjustment are increased noise in the pump, uneven and insufficient lifting speed and other malfunctions in the operation of the hydraulic drive caused by insufficient opening of the channels of the hydraulic distributor for the passage of oil when the pump motor is turned on. This adjustment is made by moving the push bars that include the electrical contacts. The bar engages contact when the forks are lifted, and the bars engage contact when the Frame is tilted forward and backward respectively.
Of the main components of the hydraulic system of loaders in ports, piston and plunger cylinders of the fork lift and frame tilt mechanism are usually repaired, and sometimes gear and vane hydraulic pumps are repaired. As a rule, hydraulic equipment (spool valves, hydraulic boosters, etc.) is not repaired in port workshops, and worn-out and damaged hydraulic equipment is replaced with a new one.
The quality of repair and assembly of loader power cylinders must be checked by static pressure. Cylinders are tested for strength, density and idle pressure by the working oil of the hydraulic system at its temperature of 30-50 °C.
The strength and density test is carried out at double working pressure for 5 minutes. At the same time, oil leakage from the cylinder through seals and welding points is not allowed.
The passage of oil from one working cavity to another is checked at operating pressure and is allowed no more than 5 cm3 / min for cylinders with a diameter of up to 100 mm and 10 cm3!min For cylinders with a diameter of more than 100 mm.
Idling of the cylinder should occur freely at an oil pressure of no more than 10-12% of the working pressure, which indicates the absence of distortions and tightening of the seals.
Forklift hydraulic systems use gear and vane pumps. Typically, loader pumps have some margin of performance, and therefore, with little wear, the decrease in the volumetric efficiency of the pump caused by it is not reflected in the operation of the machine.
Repaired, as well as new pumps, before installing them on a loader, must be tested to verify their operability and volumetric efficiency. Pumps in operation must also be periodically tested to check their technical condition. The test can be done with a flow meter or a measuring tank test rig.
A test stand with a measuring tank is shown in fig. 6. At the beginning of the test, turn on the electric motor and allow the pump under test to pump oil to the drain into the supply tank by closing the valve and opening the valve until the oil temperature reaches 40 °C.
Rice. 6. Test bench for hydraulic pumps
Then, having adjusted the throttle according to the pressure gauge so that the pump operates at a pressure of 15-20 atm, the oil is pumped into a measuring tank and, by measuring the tank filling time, the actual pump performance is determined. During the pump test, the absence of oil leakage through the seal is checked. The operation of the pump should not be accompanied by noise and knocking, the oil should not quickly heat up and emulsify.
After the repair of the hydraulic system of the loader, its general test is carried out. Before testing the hydraulic system, it is necessary to remove air from it and test the operation of the pump and hydraulic distributor separately. To remove air from the system that accumulates in the upper part of the lift cylinders, slightly unscrew the plug that closes the air outlet, operate the lift cylinder several times to its full stroke until oil appears from under the plug, then wrap the plug. If required, replenish the supply tank with oil.
After testing all movements in idle, they begin to test them under a working (rated) load. The tightness test of the system is carried out in the positions of the fork and frame of the forklift, at which the loads on the rods and plungers of the power cylinders will be maximum. In this case, no oil leakage should be observed through the pipeline connections and the seals of the rods and plungers of the cylinders and pump shafts. The magnitude of internal leaks is judged by the magnitude of the displacement of the rods and plungers of the power cylinders under rated load with the valve spools closed. In this case, the forks (cargo carriage) should not fall by more than 2 mm / min when tested for 5 minutes, and the frame of the forklift should not tilt by more than 3 ° for 10 minutes.
The value of oil pressure in the hydraulic system is measured (by pressure gauge) when it is idling and under rated load. The pressure in the system during idle operation should not exceed 12-15%, and under load - 110% of the value of the passport pressure. Abnormally high pressure in the system indicates high mechanical resistance, which can be caused by inaccurate assembly of components, misalignment of guides, jamming of rollers, strong clamping of lip seals and oil seals, etc.
Rice. 7. Scheme of skew of the movable frame of the forklift relative to the fixed one
When testing the hydraulic system, the speed of working movements (comparison with passport ones) and their smoothness are monitored.
Forklift. The wear of the guides of the telescopic frame of loaders is not always given sufficient attention, especially since it is able to work with large wear of the guides. However, this wear can, in some cases, cause accelerated wear on one of the loader's most difficult-to-repair components, the lift hydraulic cylinder.
As can be seen from fig. 7, the piston of the cylinder is rigidly connected by a rod to the movable part of the telescopic frame, while the cylinder itself is rigidly connected to the fixed part of it. The piston rod can be located strictly along the axis of the cylinder only if there is no mutual shift in the horizontal direction or distortion of the movable and fixed parts of the telescopic frame.
The load lifted by the forks of the loader creates a moment that contributes to the mutual distortion of the parts of the telescopic frame, which acquires the greatest value when the forks are raised and the clearances are increased. As a result, with a large wear of the frame guides, the rod warps by a value of b relative to the cylinder and the piston begins to touch the cylinder walls with its metal parts. In this case, not only wear of the cylinder occurs, but scoring on its surface can also occur. Therefore, for loaders (for which the gaps in the guides are adjustable), the gaps should be checked and adjusted periodically, and in other cases, when the first signs of the piston body touching the cylinder walls, it is necessary to replace the worn guides with new ones.