The self reducing valve uses the output oil flow of the main pump to reduce it as the control pressure, which acts on the solenoid valve and PPC valve, similar to the function of the hydraulic pilot pump, and is used to provide control oil pressure.
Symptom: the working device of Komatsu PC200 excavator is slow.
Inspection results of hydraulic self pressure reducing valve of Komatsu PC200 excavator: the pressure of PPC valve is 20kgf/cm2, which is less than the rated pressure of 33kgf/cm2.
Fault analysis and inspection method of hydraulic self pressure reducing valve of Komatsu PC200 excavator:
1. After inspection, the engine speed is normal and the hydraulic oil circuit pressure is normal.
2. Check the self reducing valve again and find that the cone valve is stuck, dirt in the hydraulic oil is clamped between the cone valve and the housing, causing a gap, and the pressure PR cannot reach the set pressure.
No matter how the joystick operates, the control oil pressure output from the PPC valve does not change much, so the movement of the main control valve spool is small, and the flow to the working device is also small, resulting in low speed of the working device.
Troubleshooting of hydraulic self reducing valve of Komatsu PC200 excavator: after cleaning, install the self reducing valve, and check that the pressure of PPC valve returns to normal, and the fault disappears.
