The common seal of construction machinery is the seal ring, also known as oil seal. It can isolate the oil and prevent the oil from overflowing or passing through. The hydraulic oil will break down the oil seal of the gear pump frame and overflow, resulting in oil seal string. The oil leakage of the gear pump will seriously affect the normal operation of the machine. This article will summarize the four reasons that cause the oil seal of hydraulic gear pump to break down and spill oil.
1) Oil seal quality
The lip geometry is unqualified, and the tightening spring is too loose, resulting in air leakage in the air tightness test. After the gear pump is installed, it is easy to cause the oil seal to be punctured and oil spill. Replace the oil seal and check its material, geometry and size.
2) Processing and assembly quality of gear pump
Due to the processing and assembly quality of the gear pump, the rotation center of the gear shaft is not concentric with the stop of the front cover, resulting in eccentric wear of the oil seal. Check the symmetry and displacement of the front cover bearing hole to the locating pin hole, and the coaxiality of the front cover seam to the frame oil seal hole.
3) Sealing ring material and processing quality
Due to the problems in the material and processing quality of the seal ring, the seal ring is cracked and scratched, and the secondary seal is not tight or even invalid. A large amount of pressure oil enters the oil seal of the framework without time to return the oil, thus causing the oil seal to be punctured and oil spill. The sealing ring material and processing quality shall be inspected.
4) Machining quality of transmission spline shaft
Since the internal spline of the transmission spline shaft is connected with the external spline of the gear pump, it is installed on the loader together. If the coaxiality of the spline shaft during spline processing is out of tolerance, the rotation will not be concentric. This will cause the gear shaft to swing, affect the oil seal seal, and cause the oil seal to leak. Check and control the coaxiality of the internal and external splines of the spline shaft.
