Kyotechs | CX210B Monitor for Excavators | High-Quality Parts

A control valve failure can cause improper hydraulic function, insensitive operation, hydraulic oil leakage and unstable system pressure.

Digging powerlessness can be divided into two situations: one is digging powerlessness, the engine does not hold back, and the load feels very light; the second is digging powerlessness, when the boom or dipper stick is extended to the bottom, the engine is seriously held back or even stalled.

①, digging powerlessness but the engine does not hold back. The magnitude of the digging force is determined by the output pressure of the main pump, and whether the engine holds back depends on the relationship between the oil pump absorption torque and the engine output torque. The engine does not hold back, indicating that the oil pump absorption torque is small and the engine load is light. If the working speed of the excavator is not obviously abnormal, the maximum output pressure of the main pump, that is, the system overflow pressure, should be checked in particular. If the overflow pressure measurement value is lower than the specified value, it indicates that the overload overflow valve setting value of the hydraulic circuit of the mechanism is incorrect, resulting in premature overflow of the mechanism and powerlessness. The machine can be adjusted by turning the adjustment screw.

②, digging powerlessness, engine holding back. The engine holding back indicates that the absorption torque of the oil pump is greater than the engine output torque, causing the engine to overload. This fault should first check whether the engine speed sensing system is normal, and the inspection method is similar to the engine inspection method described above. After the above detailed inspection and troubleshooting, the engine speed sensing system will resume normal function, the engine stalling phenomenon will disappear, and the digging force will return to normal.

Regularly lubricate the swing bearing, check if the grease is sufficient, inspect the bearing for wear or looseness, and adjust or replace it if necessary.

The pressure relief valve protects the hydraulic system from damage caused by excessive pressure by releasing excess hydraulic oil when the pressure exceeds the set value.