A hydraulic pump is the power source of all hydraulic systems, it is the energy conversion device that converts mechanical energy into hydraulic energy, and its technical performance is directly related to the power and reliability of the vehicle. A hydraulic pump is a component with a high failure rate of the hydraulic system, so what is the main reason for the failure of the hydraulic pump? This paper will make a detailed analysis.
1.Pump internal parts wear: internal parts wear will cause internal leakage. The leakage area between the floating shaft sleeve and the end face of the gear is large, which is the main part causing internal leakage. The clearance of the mating surface increases, the volume efficiency decreases due to wear and internal leakage, and the output power of the oil pump is much lower than the input power.
2.The aging of the pump seal element: the aging of the seal element causes the air to be sucked into the oil pump from the gap between the oil seal and the spindle journal or from the junction of the oil inlet plate and the oil pump housing, and enters the oil tank through the return pipe, producing a large number of bubbles in the oil tank. It will cause the oil in the tank to decrease, and the lifting will be slow or unable to lift. The oil seal must be replaced to troubleshoot the problem.
3.Pump leakage: leakage is directly related to the output flow of the hydraulic pump, and will affect the stability of the hydraulic system speed and the size of the output power. The reason: the center spring of the plunger pump is damaged, so the cylinder body and the oil distribution pump lose the sealing; Oil seal or seal ring damage; Poor sealing surface; Pump parts wear, the gap is too large.
4.The pump oil supply is insufficient or has no oil pressure.
5.Pump working noise is too large: Suction phenomenon is serious; The oil level of the suction pipe is shallow or the oil level of the tank is too low; Hydraulic pump shaft and motor shaft coaxial difference; The coupling is poorly installed, the coaxial degree is poor and there is beating; The oil suction filter is partially blocked; Oil viscosity is too high; Suction tube or pump suction cavity is not smooth; The oil suction end connection is not tightly sealed, air enters, and the oil suction position is too high; Air enters from the oil seal of the pump shaft; Pump cover screw loose; The pump and the shaft coupling are different or loose; There are bubbles in the oil; Suction filter passing capacity is too small; The speed is too high; Pump body cavity passage obstruction; Gear pump tooth shape accuracy is not high or poor contact, pump parts damaged; The axial clearance of the gear pump is too small, the vertical degree of the inner hole and the end face of the gear or the parallelism of the two holes on the pump cover is blocked; Pipeline vibration.
6.Pump no pressure, pump shaft reversal; The pump does not absorb oil.
7.The amount of oil pumped is insufficient or the pressure cannot be raised.
Fault cause: The suction pipe or oil filter is partially blocked; The oil suction end connection is not tightly sealed, air enters, and the oil suction position is too high; The individual blade of the vane pump is reversed, and the movement is not flexible; System leakage; Gear pump axial and radial clearance is too large; Vane pump stator inner surface wear; The wear between the plunger and the cylinder block or the oil distribution disc and the cylinder block, and the return of the plunger is not enough or cannot be returned, resulting in the loss of seal between the cylinder block and the oil distribution disc; Piston pump variable mechanism failure; The end of the side plate is seriously worn and the leakage is increased.
8.The hydraulic pump is abnormally hot when working.
Failure cause: poor assembly of the pump; The quality of hydraulic oil is poor, and the internal wear is intensified. The return pipe is not smooth; The impact of environmental conditions; Oil viscosity is too high or too low; Serious friction between side plate and shaft sleeve and gear end face; Fuel tank volume is too small, poor heat dissipation;