Five Common Faults of Excavators

Electrical system failure

1. The battery power is insufficient. At this time, the battery should be charged in time, the liquid level of the battery should be checked, and the electrolyte should be replenished to the specified height in time. If it is found that the battery is aged and poorly charged, it should be replaced, and at the same time, the daily maintenance of the battery should be paid attention to, so that the battery is not always in a state of power loss.
2. Repair or replace the starter when the starter fails.
3. Repair or replace the generator in case of generator failure.
4. Check the line and repair the line fault.

Engine oil circuit failure

1. Gas resistance of low-pressure oil circuit
Under the suction of the oil delivery pump or fuel injection pump, the fuel is sent from the fuel tank to the high-pressure pump through the low-pressure oil circuit. If the low-pressure oil circuit is not tightly closed, or the oil level in the oil tank is too low, and the vehicle is parked and driven obliquely, the air will enter the oil circuit; If the temperature is high and the fuel evaporates, it will also form an air lock in the low-pressure oil circuit, resulting in unstable engine operation, automatic flameout or engine failure to start.
2. The oil circuit is blocked
The common parts of oil blockage mainly include oil suction pipe, filter screen, diesel filter, vent hole of oil tank cover, etc. The main problem of oil blockage is that substandard diesel oil is injected, or impurities are mixed in the refueling process. The key to prevention is to ensure that diesel oil is clean and oil path is sealed, oil path is regularly maintained, cleaning and maintenance of diesel oil filter are strengthened, filter element is cleaned or replaced in time, oil tank is cleaned in time according to operating environment conditions, and sludge and moisture at the bottom of oil tank are completely removed.
3. Failure of fuel injection pump
The fuel injection plunger and the delivery valve couple are seriously worn, which makes it difficult to start the engine. At this time, the plunger and oil outlet valve should be replaced in time.

Excavator is weak.

1. The engine has enough power and operates normally, while the excavator works slowly and is unable to dig.

Walking deviation of excavator

1. Hydraulic pumps are faulty. Under normal circumstances,excavatorsuse double pumps. Walking deviation often means that one pump is faulty. The simplest judgment method is: switch the two high-pressure oil delivery pipes of the hydraulic pumps. If the original slow speed becomes faster, the original fast speed becomes slower, which proves that one pump is faulty. Methods: Dismantle the hydraulic pump, replace the damaged parts, and then go to the test bench for debugging. Oil leakage of traveling motor safety valve The oil leakage of the safety valve will cause the pressure in the system to be too low, and the speed of the traveling motor will not be enough, resulting in traveling deviation. The elimination method is: replace the damaged travel motor safety valve; When judging, the left and right walking motors can be safely exchanged to see if they deflect when walking in the reverse direction. When the digging machine goes sideways, if the spring in the walking main valve becomes soft or broken, or the valve core is stuck, it may cause the oil pressure to decrease and the walking deviation will occur. When checking, measure the pressure of the oil circuit of the walking main valve. The normal value is 32.5Mpa. If the traveling main valve is damaged, it should be replaced or repaired.

Excavator oil temperature is too high.

Excessive oil temperature is a common fault of excavator hydraulic system, and its causes are complex, which is often difficult to deal with.
1. The heat dissipation efficiency of the radiator is low. By replacing the tube-type radiator with the plate-fin radiator, the radiating area can be increased by 8cm, and the temperature difference between the inlet and outlet of the radiator can be increased from 7 C to 10 C. The effect is very obvious.
2. The one-way valve on the hot oil return road fails. The resistance of the radiator is greater than the protection pressure, so that the hot oil in the oil return circuit can be directly returned to the oil tank without the radiator; The cleanliness of the system is poor, the check valve is stuck by dirt, the valve core is in the normally open position, and the radiator doesn’t work; The opening pressure of the check valve cannot be guaranteed.
3. The air duct arrangement of the engine is unreasonable. The irrationalities of the existing air duct are as follows:①The air intake of radiator is not enough. You can open some long slots in the side door to increase the air intake. ②There is a gap around the radiator and the engine, which is not effectively sealed, and the front of the counterweight is concave, which makes the hot air form vortex, resulting in poor heat dissipation effect. A sponge can be stuck between the radiator and the engine for sealing, and the front of the counterweight can be changed from concave to flat. ③ The main pump of the hydraulic system lacks the heat insulation board, which causes the hot air from the engine to blow directly to the rear side wall of the hydraulic oil tank, causing the oil temperature in the oil tank to rise. It can be improved by adding heat insulation board. ④. The fins of the radiator air duct of the hydraulic system are lodging or the oil duct is blocked, resulting in increased wind resistance and poor heat dissipation effect. The lodging fins should be adjusted in time, the air duct blockage should be cleared, and water with a certain pressure should be used for washing regularly to ensure the smooth air duct. ⑤. Improper selection of hydraulic oil brand or poor oil quality. Low viscosity of hydraulic oil will increase internal leakage, reduce efficiency and generate heat; If the viscosity is too high, the fluid pressure loss will increase, which will generate a lot of heat and cause the oil temperature to be too high. At the same time, poor oil quality is easy to emulsify, which can aggravate the damage of hydraulic components.
Through the above analysis, we can see that 80% of excavator failures are caused by untimely maintenance or improper operation. At the same time, it is necessary to improve the technical level of operators, reduce the occurrence of failures and ensure the smooth progress of engineering construction.