Many excavator owners have used excavators for many years, and have an understanding of common problems such as walking faults and abnormal rotation of excavators. Some simple faults can be repaired by themselves. However, if you encounter the examples mentioned in this article, it may be difficult to deal with by yourself. This article will explain a fault case of walking deviation when encountering resistance, which is only for reference.
1. Fault phenomenon
The construction environment of the excavator is mine. The operator found that during the process of walking on the flat ground at the same time, all actions such as machine walking are normal, but in case of resistance or in the process of climbing, the left walking motor is weak, and it is accompanied by obvious walking deviation.
2. Fault analysis
This fault phenomenon is a special phenomenon. According to the phenomenon analysis:
1) The lubrication of the left travel valve core and valve body is not smooth, and the jamming phenomenon occurs.
2) The front pump of the main hydraulic pump is worn and the variable mechanism variable is not good.
3) The up and down travel of the left traveling main valve core is stuck, or the valve core is worn.
4) The oil seal tightness of the central swivel joint decreases, resulting in large oil drain.
5) There is a problem with the valve body of the travel motor itself.
The above are the common causes of walking deviation, so start to check one by one after analysis.
2. Fault inspection
In order to accurately judge the fault point, confirm again that the excavator does not deviate when walking on the flat road, and deviates to the left when encountering resistance or climbing.
1) Check the pressure of the front and rear pumps of the main pump through the wall gauge, and eliminate the fault of the main pump itself.
2) Check that the overflow pressure of the right travel motor works normally, and check that the overflow pressure of the left travel motor is different from the normal pressure. Then exchange the oil pipes of the left and right travel pilot control valves, and the left travel motor is still weak. Troubleshoot the left travel pilot control valve.
3) The left and right working oil pipes are exchanged and walked at the same time. The left travel motor is still weak, so the fault of the left travel main valve is eliminated.
4) Open the oil return pipe of the central swivel and observe the oil return state of left and right walking alone. There is no difference. Troubleshoot the center swivel.
5) After disassembling and inspecting the left traveling overflow valve, it was found that the internal valve core was stuck and did not return. After careful inspection, it was found that impurities entered into the overflow valve of the left traveling motor, which stuck the valve core and caused internal leakage.
3. Treatment methods and suggestions
Disassemble, clean and grind the overflow valve, and assemble it after confirmation. The test excavator works normally, and there is no walking deviation when climbing against resistance.
If you have encountered or will encounter similar fault problems in the future, you must first carefully confirm the fault phenomenon. Only by clarifying the fault phenomenon can you analyze the causes one by one. We should understand its working principle and oil circuit trend, eliminate it step by step, and we can quickly check the fault point.
The components of the hydraulic system are precision components, which play a great role and are expensive. If you don't have professional disassembly and assembly skills and special tools, you'd better not repair them by yourself.
