First, the pump body wear and maintenance:
The surface wear of the gear oil pump is mainly the arc-shaped working surface of the oil suction section. If there is slight wear, it can be used after grinding and deburring with oil stone. The pump body is molded from cast iron, and new parts should be replaced when there is severe wear. If both ends of the pump internal gear are repaired by grinding, the width of the pump body should also be changed, which is equal to the size of the gears removed at both ends. The reworked end faces of the pump body should meet the technical requirements shown in Figure 3.
Second, gear wear and maintenance:
The wear parts of the gears are mainly the meshing of the teeth, the involute working surface and the plane of the two ends of the gear. When it is slightly worn, the tooth surface can be polished with oil stone, and the two ends are flat and polished on the flat plate. When the tooth surface of the gear is seriously worn, the new gear should be replaced. If only the flat ends of the gear are worn, the surface can be ground and polished.
Third, the shaft wear and maintenance:
The wear of the shaft in the gear oil pump is mainly due to the frictional wear between the two ends of the shaft and the supporting needle, which makes the shaft diameter smaller. If it is slightly worn, the diameter of the shaft can be increased by plating a layer of hard chrome to repair the shaft. If the shaft wears seriously, it should be re-manufactured with 45 steel or 40Cr steel. After the shaft blank is roughed and finished, the bearing part should be heat treated, the hardness is HRC60-65, and then ground, so that the surface roughness of the bearing mating part is not Ra. It is larger than 0.32 μm; the roundness and cylindricity tolerance of the shaft is 0.005 mm; the gear matching portion is H7/h6, and the surface roughness Ra is not more than 0.63 μm.
Fourth, the maintenance and replacement of the needle roller bearing for the pump:
After the parts in the pump are repaired, the bearing needles should be replaced. The requirements for needle roller are: the dimensional error of all needle roller diameter should not exceed 0.003mm, the length tolerance is 0.1mm, and the clearance with the shaft should be about O.Olmm; when the needle roller is assembled, it should be filled in the bearing shell according to the quantity requirement. The needle rollers should be arranged parallel to each other.
Six, wear repair of the two ends of the cover:
The end cap of the gear oil pump is made of cast iron. After the wear phenomenon occurs, it can be slightly polished and flattened on the flat plate. When the wear is serious, it should be ground and flattened on the surface grinder. The plane contact between the repaired end cap and the pump body should be no less than 85%. The flatness tolerance, the perpendicularity of the end face to the centerline of the hole, the parallelism tolerance of the end faces and the center of the two shaft holes The parallelism tolerance of the line is O.Olmm. The surface roughness Ra after grinding should be no more than 1.25 μm.