Vane pumps are mostly used as medium and low hydraulic sources. Pay attention to the viscosity of hydraulic oil during use. It is recommended to use oil with 2.5 ~ 5 ° C eva50 viscosity, and regularly check the oil or composition; The capacity of the oil tank shall be 3 ~ 6 times of the pump flow per minute, etc. Pay attention to prevent bearing axial force, otherwise it will lead to early wear of oil distribution plate and decrease of pressure and efficiency. The oil inlet pipe of vane pump shall not leak. Pay attention to the following two points during installation and use.
① The rotating speed of vane pump is required to be high. When the rotating speed is too low, the vane pump cannot be close to the inner surface of stator, and the pressure cannot be established. Too high rotating speed will cause insufficient oil absorption and air suction.
② The anti pollution ability of vane pump is worse than that of gear pump. Therefore, the accuracy of oil filter in oil inlet circuit shall be set as 30 × M.
The troubleshooting of Hitachi excavator vane pump is as follows.
1. The pump does not deliver oil, and the pressure gauge shows no pressure
① The tank level is too low. Fill the oil tank with hydraulic oil.
② The oil suction pipe or oil filter is blocked by dirt. Remove dirt.
③ The oil suction chamber (oil seal, oil suction pipe joint of pump body) leaks. Whether there are sand holes or air holes in the oil suction chamber, and if so, replace the pump body; Check whether the oil suction pipe has cracks, whether the pipe joint nuts are tightened, and check the sealing performance and quality of the oil seal.
④ The blade is stuck in the rotor slot and cannot be thrown out at all, or the blade is broken, resulting in the interworking of high and low pressure cavities. The fit between blade and groove is too tight, the fit clearance shall be 0.015 ~ 0.02mm, and burrs shall be removed.
⑤ The oil distribution plate is damaged and the oil distribution plate is in poor contact with the pump body, resulting in the communication of the sealing area and slight deformation on the side of the oil distribution cover. Trim the contact surface between the oil distribution plate and the rotor.
⑥ The motor is reversed. Rotate the motor in the forward direction.
⑦ The pump speed is too low. Adjust the speed or replace the motor.
⑧ The oil viscosity is too high. Use oil with proper viscosity.
⑨ The connecting key is not installed, or the spline shaft does not rotate, or the spline shaft is twisted and broken. Install the connecting key and replace the spline shaft.
⑩ The oil suction pipe is too long. Make the pump close to the oil tank, that is, shorten the length of the oil inlet pipe accordingly.
? The quality of the pump body is poor, and there are sand holes, pores, etc. Replace the pump body with a new one.
2. Low volumetric efficiency and low pressure rise
① The blade or rotor is installed reversely. Correct.
② The fit clearance between blade and blade groove is too large. Re prepare the blade according to the blade groove size. The fit clearance between blade and blade groove shall be controlled within the range of 0.013-0.018mm.
③ The stator oil suction cavity is seriously worn, and the blade top is damaged or roughened. The stator can be turned 180 °, the oil suction chamber and oil pressure chamber can be interchanged, and the positioning hole can be reprocessed; Trim the top of the blade or replace it.
④ The inner curve of the pump stator is worn. Repair or replace on a special grinder.
⑤ The axial clearance is too large and the internal leakage is serious. Repair the stator, rotor and blade, and control the axial clearance between 0.04 ~ 0.07mm.
⑥ Poor oil inlet. Clean the filter and replace the working oil.
⑦ The oil seal is poorly installed or damaged. Refit or replace.
The system is leaking. Check the leakage of pipes, pipe joints and valves in the system.
