Hydraulic pump is the power source of excavator hydraulic system. It is an energy conversion device that converts mechanical energy into hydraulic energy. In the hydraulic excavator, the hydraulic pump is also the most faulty component, and once the hydraulic pump fails, it will immediately affect the normal operation of the excavator hydraulic system, or even can not work.
1. Most of the common faults of gear pump are caused by the wear of its internal friction pair. Its normal wear increases the radial clearance and axial clearance (i.e. section clearance) and aggravates the leakage in the gear pump. In serious cases, the holes in the pump body or the plates on both sides cannot be repaired. In addition, the shaft seal is also a frequently damaged component.
2. Vane pump is different from gear pump, its normal wear is very small and the service life of parts is long. The main cause of vane pump failure is oil pollution, which is because the moving pair of vane pump is matched accurately. When pollutants enter the friction pair, it is easy to produce abnormal stagnation or wear. In addition, the self-priming performance of vane pump is not as good as that of gear pump, especially for vane pump with small displacement. Therefore, whether the oil is clean and whether the oil suction is smooth are two problems that need special attention in the operation of vane pump.
3. The weakness of radial piston pump in structure and motion performance is large radial force, poor self-priming ability and high matching accuracy between plunger and plunger hole; The machining accuracy of parts of axial piston pump is high. Therefore, the plunger pump has high requirements for the cleanliness of the oil, that is, the filtration accuracy of the plunger pump is higher than that of the gear pump.
