The oil leakage of the pump turns a large amount of hydraulic energy into heat energy, causing the oil temperature to rise and the working conditions to deteriorate. The oil leakage of the gear pump can be divided into internal leakage and external leakage. Internal leakage reduces the output flow of the pump and the pressure rise is not high. In addition to the above disadvantages, external leakage also pollutes the environment. Therefore, it is necessary to reduce internal leakage and avoid external leakage. The method to reduce the internal leakage is to properly adjust the movement clearance of the pump. If the clearance is too large, the internal leakage will increase; If the clearance is too small, the friction will increase. Causes of external leakage:
1) The oil return hole on the front and rear pump covers is blocked, or the hole is not drilled through during processing. This requires cleaning or drilling through.
2) The pump cover and sealing ring are too loose to form oil leakage, which can be solved by adjusting the clearance.
3) The shaft seal lip is scratched by the main shaft keyway or the skeleton spring falls off. This can be replaced or reinstalled.
4) The sealing surface of parts is severely scratched. The sealing surface shall be reground to eliminate scratches.
5) The inner diameter of the oil seal groove is too small or the groove chamfer is too small, which makes the oil seal inclined, resulting in oil leakage. The groove size shall be checked, and the groove or chamfer shall be machined as specified.
6) If the shaft chamfer is too rough or too small, causing the lip of the seal to turn over, check the roughness or chamfer. During assembly, the chamfer shall be greased.
7) The seals shall be replaced if they are used for too long under high temperature, or the seals have poor resin, or the seals lose elasticity due to improper assembly, resulting in external leakage.
During installation, the pump body is installed reversely so that the oil outlet is connected to the unloading groove. Or when the test run is correct, the steering is wrong, and the oil seal on the shaft is broken down, causing external leakage. This is because the oil inlet of the pump is connected with the oil seal through the oil return channel. When the pump reverses, the oil inlet becomes the oil outlet, and the pressure oil breaks through the oil seal through the oil return channel, or the oil seal is flushed out of the pump body to form external leakage. This should correct the steering of the pump and replace the oil seal with a new one.
