Analysis of failure causes of small wheeled excavators

Analysis of failure causes of small wheeled excavators

2020-11-13 10:22:29   source:chinaminiexcavator.com  edit:xiaoli

How to deal with the failure of the green small pulley excavator?

Analysis of failure causes of small wheeled excavators

1. Insufficient power of all working devices: the excavator repairs the main safety valve failure, and the normal working pressure cannot be determined.

2. Some working equipment does not work. The left and right movements of the boom, tie rod, and bucket are insufficient, and the main circuit breaker fails.

3. Insufficient power of the working device (the boom is raised or lowered, the bucket is opened or closed, the rod is extended or retracted): If the working device performs two actions (for example, the rod is retracted), the auxiliary pressure reducing valve fails. If the pressure is insufficient during the extension process, please check the oil filter in the hydraulic oil tank (whether the oil filter has a damaged seal).

4. When the operating handle is in the middle position, the arm, arm and bucket move to the air side (for example, the arm support and bucket are opened, etc.). ). When the pressure is lower than the specified pressure, the auxiliary safety valve opens. The safety valve does not reach the pressure required by the cylinder load.

1. Greening small pulley excavator low-speed expansion and contraction: The maintenance of the green small pulley excavator caused the oil circuit logic valve to be contaminated, causing the piston hole to be blocked or the piston stuck in the open position, so the main oil pump always returned to the hydraulic oil tank.

2. The boom rises slowly: the boom oil circuit logic valve is dirty, the boom oil circuit logic valve piston is removed and cleaned, the boom oil circuit logic check valve is dirty, the stuck position is closed, or the piston is stuck in the middle position. In this case, there is noise during boom raising, the logic check valve is removed, and cleaning is performed.

3. The starter motor rotates and the engine does not start: the rocker arm and boom oil circuit logic valve is contaminated, the oil filter or throttle hole installed in the front is blocked, and the hydraulic circuit is closed (hydraulic lock). Remove the piston rod, move the boom oil circuit logic valve, and clean the oil filter or orifice.

4. The speed in both directions is very slow: the shuttle valve leaks air, the rotary spool cannot be completely moved into place, and the rotary brake is not released. For the solution, check the pilot control pressure. If the pressure is lower than the pressure, the valve pressure (about 4 MPa) will change the shuttle valve. If the pressure is normal, remove and clean the valve.

5. Insufficient rotation power: Excavator maintenance causes failure of the safety valve of the rotation circuit or oil leakage of the check valve.

6. When the rotation stops, the rotating device slides too much, and mechanical noise will be generated when the machine stops: the reason is that when the rotating control handle is in the middle position, the rotating brake does not work. The solution is to remove the valve and clean it.

This is an introduction to the failure case analysis of a green small pulley excavator. Hope it helps you.


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