Repair of the main parts of the forklift gear pump

(1) Wear and adhesion of the outer circle of the gear increase the radial clearance. In mild cases, it has no obvious impact on use and does not require repair. In severe cases, gears should be replaced.

The end faces on both sides of the gear are worn. In mild cases, there will be lines. The burr marks can be ground off by grinding. When the wear is severe, it can be ground smooth on a grinding machine. However, as long as the end face of one gear is worn, the other gear also needs to be ground simultaneously to ensure that the thickness difference between the two gears is within 0.005mm. When grinding, it is also necessary to pay attention to ensuring that the precision between the end face and the hole, as well as between end faces, is high. After grinding, sharp edges and burrs should be removed with an oilstone grinder, but chamfering should be avoided.

The gears of the oil pump all work in one direction, so the tooth surfaces are all worn on one side. The burrs on the worn gear surfaces can be removed with an oilstone, and the meshing positions of the gears can be changed to restore the working performance of the oil pump.

(2) When the end faces of the bearing housings are worn or scratched, the four bearing housings can be placed on a surface grinding machine, and the end faces can be ground out at one time with the non-gear contact surface as the reference.

The inner hole generally wears less. If the wear is severe, it can be ground or the hole diameter can be ground to the repair size, and needle rollers can be selected.

When the bushings equipped with side plates or axial floating are worn, scratched or have grooves, the damaged surfaces can be polished. The method is to apply grinding paste No. 400-600 on a smooth surface, add washing oil or wax, and gently rotate it on the side plate surface for polishing.

(3) Pump body: Wear of the pump body usually occurs in the suction chamber. Some oil pumps can be repaired by the transposition method from a structural perspective. That is, the pump body is rotated 180° around its own axis to transform the suction chamber into a pressure chamber and restore its working capacity.

For oil pump bodies that cannot be repaired by the transposition method, the copper sleeve inlaying method can be used for restoration.

When the gears are ground due to end face wear, in order to maintain the axial clearance, the rear end face of the pump body needs to be ground to an appropriate thickness.