Reasons for walking deviation of small excavator

It is difficult for a small excavator to turn right when moving forward or backward for about 5,000 hours.

According to the analysis, the main causes of deviations are related to hydraulic components, such as the hydraulic main pump, the pump regulator and the stroke valve core on the main control valve, the center connector and the stroke motor, as well as the pilot pressure and track tension.

First, check that the tension of the two tracks is the same, support two crawler walking bands respectively, and check the distance between the large sinking of the track and the horizontal line of the chassis.

Secondly, from the dashboard check before and after the pump pilot pressure is consistent. If not, it should be adjusted so that when the engine slows down (the engine), the front and rear pump pilot pressure is 3.2MPa and at high speed it is 4MPa.

Then, the high pressure tube of the driving motor is interchangeable with the center joint. If the failure phenomenon in the test machine changes, the drive motor can be eliminated; otherwise, if the drive motor fails, the drive motor should be removed.

The four tubing of the left main stroke and the right stroke can be exchanged between the main control valve and the center joint. If the failure occurs during testing, the center connector may fail. Otherwise, the center connector should be removed. Open it and find out why it failed.

The left and right stroke control valve core is tested, and it is found that the valve core in the valve body is elastic, no damage, can eliminate the control valve.

When two main pump regulators are swapped, the fault of the operation deviation is found to have changed, so the fault can be judged on the regulator, otherwise the fault should be on the hydraulic main pump.

Through the inspection of the above steps, the fault should be on the pump regulator. When removing the valve, it is found that the O-ring on the valve core has aged and damaged, resulting in the valve core movement is not flexible, can not correctly adjust the angle of the slant plate, so that the pump speed is reduced, walking faster. Clean the pump regulator, replace the O-ring, install the test machine fault disappears