Whether the excavator moves forward or backward, the deviation will have a certain impact on the machine construction. Some people may think that slight deviation can continue the construction, but this will cause delay and expand the fault problem. This article will explain the whole process of handling the forward travel deviation fault of the excavator for reference only.
1. Fault phenomenon
On site observation found that the excavator deviated to the left when walking forward in a straight line, and the retreat was normal. At the same time, it is found that when moving forward to the right and turning, it is weak and slow. Although the fault is not serious on the surface, it is still scheduled to be repaired.
2. Fault analysis
According to experience, there are many fault causes that can cause this problem, and they are more common. So start from the following points for analysis.
1) Check whether the corresponding pilot pressure of traveling is low.
2) Whether the valve core of the traveling main control valve is worn or the travel of the main valve core cannot be in place due to jamming and other reasons.
3) Check whether the corresponding pressure compensation valve is worn, stuck, blocked and other abnormal conditions.
4) Whether the oil suction valve corresponding to the traveling is not tightly closed and there is oil leakage.
5) Check whether the safety valve on the corresponding travel motor is abnormal.
6) Whether the sealing ring on the center swivel is not tightly sealed.
3. Troubleshooting
Record the following data by observing the monitor.
1) The forward overflow pressure of the right travel motor is normal, and the backward overflow pressure is normal. The forward overflow pressure of the left travel motor is abnormal. The reverse overflow pressure is normal.
2) In order to accurately judge whether the speed is within the normal range, the following data are obtained through the test. Lift the excavator up the track shoe and check the travel speed of Lo, MI and hi. The travel speed of the right track shoe is normal. Lo, MI and hi are abnormal when the left track shoe moves forward. When the left track shoe is backward, the three speeds of Lo, MI and hi are normal.
3) Adjust the two safety valves of the left travel motor, and the fault remains the same.
4) Adjust the two pressure compensation valves of the left travel main control valve, and the fault remains the same.
5) When removing the oil suction valve on the left traveling forward oil circuit on the main control valve, iron filings were found.
Remove the oil suction valve on the oil circuit before walking, and remove the iron filings after disassembly. After simple grinding and cleaning, install the excavator for test, and the fault disappears. Because the inside of the left travel motor was broken before, the valve plate and cylinder block were damaged. During maintenance, the pipeline may not be cleaned, resulting in iron filings entering the main control valve.
In the future, when there are similar faults, do not just clean the inside of the motor, but also clean the relevant pipelines, so as to prevent the remaining iron filings from entering the main control valve, resulting in some valve sticking, and then walking deviation and other faults.
