During the use of large crawler excavator, there is no movement when walking back and forth on the left, and normal walking and other movements on the right. Some operators do not know what caused the failure. This article will explain how to analyze and check the fault when the excavator has the fault, which is for reference only.
1. Fault analysis
Check the left travel control pressure and overflow pressure. Check whether there is oil leakage in the traveling connecting pipeline. Generally, it is the fault of traveling motor and reducer.
The specific fault causes basically include the following aspects:
1) If the pilot pipeline of the left travel is connected incorrectly or there is a serious oil leakage, it can be judged and eliminated by checking the control pressure on the left.
2) The failure of the foot valve of the left travel control can be judged and eliminated by checking the pilot control pressure on the left.
3) For the internal fault of the left traveling reducer, the internal reduction gear of the reducer needs to be disassembled for judgment and troubleshooting.
4) Internal fault of left traveling motor, including leakage caused by plunger and cylinder wear. The removal can be judged by the main overflow pressure of traveling.
5) The main control valve of the left travel is faulty. If the valve core of the control valve is stuck, the main oil circuit will not be opened and the travel action will not be available. The removal can be judged by the main overflow pressure of traveling.
6) The left traveling balance valve, brake oil circuit and brake piston are stuck, resulting in the brake piston can not be opened and can not act. The elimination can be judged by detecting the brake oil pressure of left travel.
7) The overload overflow valve of the left travel fails, resulting in the failure to establish pressure in the main oil circuit and direct leakage, so the travel action cannot be realized. The removal can be judged by the main overflow pressure of traveling.
8) Other external force factors, such as crawler tracks and obstacles, are stuck, traveling and decelerating and cannot rotate.
2. Troubleshooting
First, check that both pressures are within the normal range. Directly eliminate the pilot oil circuit, control valve, motor, overflow valve and other fault points.
Secondly, check that the brake oil circuit is also normal, and eliminate the fault points of the brake system and balance valve.
Then, after disassembling the reducer, it was found that there were a lot of iron filings inside, and the reduction gears were worn to varying degrees. But it can rotate, and the gear oil has increased a lot.
Finally, check the motor output shaft and find that the main shaft and bearing are damaged.
Replace the internal accessories and motor shaft of the traveling reducer, replace the bearing, oil seal and gear oil, and eliminate the fault.
