1. maintenance of worn gear pump shaft
The wear of the shaft in the gear pump is mainly due to the friction and wear between the two ends of the shaft and the supporting needle, which makes the shaft diameter smaller. If it is slightly worn, a layer of hard chromium can be plated to increase the diameter of the shaft at this position, so that the shaft can be repaired. If the shaft is seriously worn, it shall be remanufactured with 45 steel or 40Cr steel. After rough and finish turning of the shaft blank, the bearing part shall be heat treated with a hardness of hrc60-65, and then ground to make the surface roughness Ra of the bearing mating part not greater than 0.32 μ M; The allowable deviation of roundness and cylindricity of the shaft is 0.005mm; The surface roughness Ra of the mating part with the gear shall not be greater than 0.63 according to h7/h6 μ M.
2. maintenance of worn gear pump body
The surface wear of the pump body is mainly the circular arc working surface of the oil suction section In case of slight wear, it can be used after grinding and deburring with oilstone. The pump body is formed by cast iron blank. In case of serious wear, it should be replaced with a new one. If the two ends of the gear in the pump are repaired by grinding, the width of the pump body shall also be changed to be the same as the size removed by grinding at both ends of the gear. The two end faces of the pump body after re machining shall meet the technical requirements.
3. maintenance after wear of gear pump covers at both ends
The end cover of the gear pump is made of cast iron. In case of wear, it can be ground and leveled on the flat plate. In case of serious wear, it should be ground and leveled on the surface grinder. The plane contact between the polished end cover and the pump body shall not be less than 85% The flatness tolerance, the perpendicularity tolerance of the end face to the hole centerline, the parallelism tolerance of the two ends and the parallelism tolerance of the two axis hole centerline are all 0.01mm. The surface roughness Ra after grinding shall not be greater than 1 five μ M.
4. maintenance and replacement of needle roller bearing for gear pump
After the parts in the pump are repaired, the bearing needle should be replaced. The requirements for needle rollers are as follows: the dimensional error of all needle diameters shall not exceed 0.003mm, the length tolerance shall be 0.1mm, and the fit clearance with the shaft shall be about 0.01mm; During the assembly of needle rollers, the bearing shell shall be filled according to the quantity requirements, and the needle rollers shall be arranged in parallel with each other.
