Created on:2021-11-30 15:55

Use and maintenance of internal gear pump

Use and maintenance of internal gear pump

(1) Use.

1) The flow, pressure, output shaft and connection installation parameters of BB-B cycloidal pump correspond to CB-B gear pump, which are interchangeable and universal.

2) BB-B cycloidal pump adopts the structure of external leakage. During use, ensure that the oil drain channel is unblocked, and the oil drain pipe shall be directly and separately led back to the oil tank.

(2) Maintenance.

The wear parts of the gear are mainly the meshing of the teeth, the involute working surface and the planes at both ends of the gear. In case of slight wear, the tooth surface can be polished with oilstone, and both ends are flat and polished on the flat plate. When the tooth surface of the gear is seriously worn, it shall be replaced with a new gear. If only the planes at both ends of the gear are worn, it can be ground and polished on the surface grinder.

The wear of the shaft in the internal 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. In case of slight wear, the diameter of the shaft at this position can be increased by plating a layer of hard chromium to repair the shaft. If the shaft is seriously worn, it shall be remanufactured with 45 steel or 40Cr steel. After rough and finish turning, the bearing part shall be heat treated with a hardness of hrc6065, 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 matching part with the gear shall be H7 / H6, and the surface roughness Ra shall not be greater than 0.63 μ m。

The surface wear of the pump body is mainly the circular arc working surface of the oil suction section. If there is 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 shall 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, which is equal to the size removed by grinding at both ends of the gear. The two end faces of the pump body after reprocessing shall meet the standard technical requirements.

The end cover of the internal meshing gear pump is made of cast iron. If there is wear, it can be ground and leveled on the plate. If the wear is serious, 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 center line, the parallelism tolerance of both ends and the parallelism tolerance of the center lines of the two shaft holes are all 0.01mm; The surface roughness Ra after grinding shall not be greater than 1.25 μ cm。

After the parts in the pump are repaired, the bearing needle should be replaced. The requirements for needle roller are: the dimensional error of all needle roller 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.

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