The hydraulic pump is one of the most important components of an excavator. Once the hydraulic pump fails, it means that the excavator cannot perform normal construction operations.
According to the analysis of Hitachi excavator maintenance masters, there are many reasons for the insufficient output flow of the hydraulic pump: such as oil temperature problems, pump body leakage, pressure plate damage and a series of reasons. Here, the master reminds everyone that the hydraulic pump is a relatively precise component of the excavator. Self-checking the fault may cause damage to other components of the excavator. It is recommended to find a professional Hitachi excavator repairer for inspection and troubleshooting!
Reasons for insufficient output flow of hydraulic pump:
①The reason for insufficient pump suction may be that the hydraulic oil level of the oil tank is too low, the oil temperature is too high, the oil inlet pipe is leaking, and the oil filter is blocked.
②Excessive pump leakage is mainly caused by poor sealing. For example, there are blisters or cracks on the bearing surface of the pump body and the oil distribution plate, the oil distribution plate is scratched by impurities, the variable mechanism and its check valve components are not well matched or sealed. This can be done by checking the foreign matter in the hydraulic oil in the pump body to determine the damaged or leaking part of the pump.
Troubleshooting is based on different reasons. For example, grinding the oil distribution plate and cylinder end surface, re-grinding the sealing surface of the one-way valve, replacing the parts with blisters or cracks, when the plunger hole is severely worn or damaged, the cylinder hole should be re-plated with copper, ground, etc. If the piston of the variable mechanism is severely worn, the piston can be replaced to ensure that the gap between the piston and the piston hole is 0.01~0.02mm. When the oil distribution plate is not tightly attached to the pump body, causing a large amount of leakage, the hydraulic pump should be disassembled and reassembled. If the viscosity of the hydraulic oil is too low and the leakage of each part is increased, the hydraulic oil must be replaced.
③The actual inclination angle of the pump swash plate is too small, so that the pump displacement is small, which requires adjustment of the manual joystick or servo control system.
④ The pressure plate is damaged. When the pressure plate of the plunger pump is damaged, the pump not only fails to self-prime, but also causes the slag part to enter the hydraulic system, and there is no flow output. In addition to replacing the pressure plate, the system should also remove the slag.
