Excavator runs greatly increases the driver's labor intensity, affecting work efficiency or even work, so it must be excluded in time. The reason and judgment method of running is analyzed by WY20-type hydraulic excavator as an example.
Reason analysis
(1) Variable double pumps P1, P2 have a damage or leakage amount is large, causing that the two pump output flows is not equal, the amount of supply of the motor 1 and the motor 2 is not equal, so that the speed of the two motor is different. Leading the excavator to run.
(2) There is a valve heart in the reversing valve 4, 10 to be stuck, so that the oil is thrown at the time of the valve, thereby causing the motor 1 and motor 2 from the air supply, resulting in running Bias.
(3) A valve is too low in the safety valve 8, 9, and the pressure is too low. When the excavator travel resistance is large, the safety valve that is lowered is opened, and a portion of the flow of the pump output is Through this valve flow back to the fuel tank, the left and right motor oil supply will be ran out.
(4) The valve 6 is stuck, and the pump P1 is simultaneously communicated with the oil supply port of the pump P1, and when the load of the right travel motor 1 is smaller than the load of the left row, the portion of the pump P1 outputs the pump P2 output. All traffic will flow at the same time to the right travel motor 1, so that the speed of the right motor is greater than the speed of the left motor, resulting in the excavator to rotate to the left.
(5) The seal in the rotary joint 3 is damaged, so that one of the oil transfer channels of the motor and the return passage, resulting in decreased the amount of oil in the motor, decrease the speed, and forming the running of the excavator.
(6) There is a leak in the motor 1 and motor 2 or damaged, resulting in different two motor speeds.
(7) The main safety valve 5, 7 has a tensile pressure too low or the valve is stuck. When the excavator is large, the safety valve for adjusting the pressure is low will open, overflow, then flow into the left, The flow of the right motor is not equal, so that the excavator will run. However, in this case, there will be slow and weakness of other working devices.
2. Judgment Method
There are many reasons why the run, it is difficult to determine which reason is caused by it, but if the method is excluded according to the "from the head to the tail", it can quickly find the reason, and avoid blind disassembly.
First, the oil pump P1, P2 is swapped, and then the test is changed, and if the direction of the running is changed accordingly, it means that the variable double pump is generated, and the corresponding pump can be found according to the lower speed of the motor. Machine repair; if the direction is not changed, it means that it is not a pump.
Then, the two oil pipes between the reversing valve 4 to the rotary joint 3 are exchanged between the two oil pipes between the valve 10 to the rotary joint 3, and if the direction of the running is changed, the multi-channel valve is illustrated. That is, the cause of the above cause (2), (3), and (4) are caused. Running left, then it is caused by the main safety valve 7, the safety valve 8, the valve 6; runs to the right, then it is caused by the main safety valve 5, the safety valve 9, can be cleaned separately, respectively. Pressure to the specified value. If the direction of run is unchanged, it means that it is not caused by multiple valves.
Finally, the inlet, oil tube and motor 2, the oil pipe, the motor 2, and the oil pipe, if the running direction changes, the problem is caused by the problem of rotary joint 3, can be replaced or repaired: if running The partial direction is unchanged, then it is a problem that the motor is low.
In addition, servo-acting valve stuck or damage can also cause running.
