For the excavator to repair this kind of fault, it should first be distinguished whether the single track is weak or the double track is weak. If single track walking is slow and weak, the result is running deviation, the above method can be used to analyze the troubleshooting. If the double track walking is slow and weak, first observe whether each action of the working device is slow and weak. If only the double track is slow and weak, it can be inspected, analyzed and investigated in the following order.
1. If the oil pressure of the traveling pilot control is too low to make the traveling valve stem fully commutate and the valve stem is in the semi-closed state, only part of the oil flow is used for the traveling motor and the traveling speed is slow, the malfunction of the pilot valve should be eliminated.
2. If the oil pressure of the walking pilot control reaches 3 MPa or so, the double track walking is still slow and weak, install the pressure gauge at the outlet of the double pump, and try to set obstacles for the double track walking, operate the walking pilot valve so that the double track can walk, observe the displayed value of the pressure gauge. If the pressure value is very low, the intact overflow pressure value of the rotary secondary relief valve can be raised to the same value as that of the local walking secondary relief valve. Then replace and install the traveling secondary relief valve with the rotary secondary relief valve. If a track travels normally while the rotation is abnormal, the original traveling secondary relief valve proves to be of poor performance, it should be repaired or replaced.
3. Damage to the sealing ring of the central rotary joint or leakage in the sand holes of the housing may also cause slow and weak walking of the double track. If the running secondary relief valve performs well, try to set obstacles to travel and measure the inlet pressure of the walking motor. If the pressure is very low, it indicates that the failure is caused by damage to the sealing ring of the central rotary joint or casing oil string. The damaged sealing ring or casing oil string of sand holes should be replaced.
4. Serious motor leakage can also lead to slow and weak track walking. If the oil pressure at the motor inlet is normal and there is sufficient flow, the speed of the motor is still very low and the speed of the motor is slower at higher oil temperature. This kind of fault is usually caused by excessive motor leakage. Excessive leakage in motor is mainly caused by excessive clearance between motor piston and piston hole and spherical clearance between copper cylinder block and port plate. The above mating parts should be repaired or replaced to improve the volumetric efficiency of the hydraulic motor.
