1. Repair of worn driving shaft and liner of gear type oil pump in diesel engine

Due to the weight of the driving gear of the oil pump and the radial thrust generated during the meshing of the passive gear, it is easy to cause eccentric wear and increased clearance between the shaft and the bushing hole. Therefore, during work, oil leakage may occur due to increased clearance, resulting in a decrease in fuel supply.

After the wear of the drive shaft and bushing, the method of repairing the journal or bushing can be used to restore the fit clearance. When there is slight wear on the shaft neck, simply press out the old bushing and replace it with a new bushing, and the shaft generally does not need to be repaired, so that the fit clearance can be restored to the allowable range. When the wear of the shaft and liner is severe and the clearance between them increases significantly, not only should the liner be replaced, but the shaft should also be chrome plated or vibration welded to increase the diameter, and then ground to the standard size to restore the fit requirements between the shaft neck and liner.

2. Repair of pump casing cavity and gear teeth after wear and tear

The wear of the pump casing cavity and gear teeth has a significant impact on the pump oil volume. When the shaft and bushing or shaft hole are severely worn, the tooth tip and the inner surface of the pump housing will make unnecessary contact during operation. Due to the higher pressure in the oil outlet chamber compared to the oil inlet chamber, under the pressure difference, there is more contact between the tooth tip and the pump housing near the oil inlet chamber. Therefore, there is more wear on the inner cavity of the pump housing at this location, which increases the gap between the inner cavity and the tooth tip. As a result, the pressure difference between the inlet and outlet chambers of the oil pump is reduced, leading to a decrease in the scraping and pressure of the gear teeth, resulting in a decrease in the supply pressure and a decrease in the pump oil volume. The wear of the inner cavity of the pump casing is generally repaired by the inner cavity embedding method.

Secondly, due to the wear of the gear teeth in the direction of tooth thickness, the meshing clearance between the active and passive gears increases. Its wear characteristic is heavy wear on one side, so the gear can be flipped 180 degrees for use.

3. Repair of worn gear end face and pump cover

There is a certain gap between the gear end face and the inner plane of the pump cover, which is called end face clearance. The wear caused by the contact surface between the gear end face and the inner plane of the pump cover during work will increase the clearance between this end face. When it exceeds the limit, it will have a significant impact on the pump oil volume.

When the gear end face wears out, the end face can be ground flat, and at the same time, the disassembly surface of the oil pump housing can be ground to ensure that the end face clearance of the pump is within the required range.