Komatsu 200-7 final drive walks slowly and weakly

Komatsu 200-7 basic information

Equipment brand Komatsu

Equipment Model PC200-7

Working hours 10100 hours

Year of manufacture 2005

Time 2016-12-06



According to the experience of years of slow and inability to repair excavators, the following diagnosis is made for Komatsu 200-7 walking slow and walking weakness:

1. Firstly detect the speed of the boom, the stick, the bucket and the swing, and the overflow pressure. The values are within the standard range. It is judged that the hydraulic pump, the self-pressure reducing valve, the main relief valve, the main control valve, etc. malfunction.

2. Secondly, the right track is propped up. Under the maximum working condition of the throttle, the time required for the track to rotate 5 turns is measured. The result is that the forward movement is abnormal and the backward movement is normal.

3. From this, it can be judged that the travel motors, the motor reducer, the travel speed solenoid valve, etc. have no faults.

4. The pilot pipe road of the pilot pipe and the working device will be exchanged and tested. That is, the boom lower pilot pipe and the left travel forward pipe route are exchanged, and the bucket excavation pilot pipe road and the right travel forward pilot pipe road are exchanged. At the same time, the boom lowering and the arm excavation pilot valve are found, and the forward speed and strength are normal, but the speed of the stick digging is slow. It can be judged that the walking pilot valve is faulty. After replacing the valve, the excavator walking speed Back to normal.

Asked the Komatsu 200-7 excavator driver to know that when the machine is working for 8000 hours or so, there is a problem when it is walking straight, and there is only a problem of low speed.

1. During the on-site inspection, it is found that the automatic speed reduction function will automatically work when the machine is walking for 4s. Read the fault codes 019 and 021 on the monitor and find that the final drive motor oil pressure switch in 019 is OFF and 021 when walking straight. The running deviation (ie, steering) oil pressure switch is ON. When turning, both oil pressure switches are ON, so it can be judged that the lines of the two pressure switches are faulty.

2. Disassemble the cab floor and check the line of the pressure switch. It is found that the two plugs are reversed. The reason is that the final drive signal oil pressure switch S30 connector and the walking steering signal oil pressure switch S31 connector are reversed, when walking straight, walking Although the oil pressure switch is closed and turned on, its electric signal is sent to the controller through the steering oil pressure switch connector S31. At this time, the steering oil pressure switch is not closed, and the electric signal is transmitted through the traveling oil pressure switch connector S30. To the controller, the governor and the pump controller judge that the machine is not doing the walking action, and the automatic speed reduction function is performed by the governor motor. At the same time, the governor and the pump controller minimize the pumping amount. At this time, even if the high-speed running gear is selected, the governor and the pump controller have no electric signal to the walking speed solenoid valve. If the walking speed solenoid valve is not energized, the machine has no high-speed running gear. After the two plugs are exchanged, the fault disappears. https://www.spfinaldrives.com/

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