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Gear pump leakage
Sep 06, 2018

The leakage of the gear pump is large, and the leakage path of the external gear has the following three points: one is the gear head clearance, the second is the gap measurement, and the third is the meshing gap.

The leakage of the end face gap is large, accounting for 80%-85% of the total leakage. When the pressure increases, the former will not change, but the deflection of the latter is greatly increased. This is the main reason for the leakage of the external gear pump, volumetric efficiency. It is not suitable for use as a high pressure pump.

Solution: Face clearance compensation uses static pressure balancing measures to add a compensation part between the gear and the cover, such as floating bushings and floating side plates.

Unbalanced force

The right side is the pressure oil chamber, the left side is the oil suction chamber, the pressure of the two chambers is unbalanced; in addition, the pressure chamber is leaked due to the tip of the tooth, and the pressure is decreasing. The two unbalanced pressures act on the radial unbalanced pressure of the gear and the shaft. The higher the oil pressure, the greater the force, the accelerated bearing wear, the lower bearing life, the bending of the shaft, and the increased wear of the crown and shaft bore.

Preventive measures: Use a pressure balance tank or reduce the pressure oil chamber.