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Analysis of the effect of hydraulic gear pump oil on pump itself

In the process of using the variable piston pump, there are always all kinds of problems. For example, recently a friend of mine told me that the oil displacement of the variable piston pump is not zero, so what should we do? Now Damon would like to share with you the maintenance skills to solve the common faults in the variable piston pump. Welcome to refer and learn.

1、 The output flow of hydraulic pump is insufficient or no oil is output

1. Insufficient inhalation

The reason is that the resistance on the oil suction pipeline is too large or the oil replenishment is insufficient. If the pump speed is too high, the liquid level in the oil tank is too low, the oil inlet pipe leaks, and the oil filter is blocked.

2. Excessive leakage

The reason is that the clearance of the pump is too large and the seal is poor. For example, the oil distribution plate is scratched by metal fragments and iron chips, and the end face leaks oil; the sealing surface of the one-way valve in the variable mechanism is not well matched, and the supporting surface of the pump body and the oil distribution plate has trachoma or grinding marks, etc. The damaged part of the pump can be identified by checking the foreign matters mixed in the hydraulic oil in the pump body.

3. The inclination angle of the swash plate is too small and the displacement of the pump is small, which requires adjusting the variable piston to increase the inclination angle of the swash plate.

2、 In the middle position, the oil displacement is not zero

When the inclination angle of swash plate of variable axial piston pump is zero, it is called middle position, and the output flow of pump should be zero. But sometimes the middle position deviates from the midpoint of the adjusting mechanism, and there is still flow at the midpoint

If the position of the brake is deviated, loose or damaged, it needs to be reset, tightened or replaced. This phenomenon can also be caused by insufficient angle maintaining force of pump and wear of inclined angle trunnion.

3、 Output flow fluctuation

The fluctuation of output flow is related to many factors. For the variable displacement pump, it can be considered as the result of poor control of the variable displacement mechanism. If foreign matters enter the variable displacement mechanism, step marks, wear marks and scars will be scratched on the control piston

The movement is unstable. Due to the lack of amplifier energy or parts damage, and the poor performance of the damper with spring, the motion of the control piston will be unstable. Variable displacement piston pump flow instability and often

This kind of fault generally needs to disassemble the hydraulic pump, replace the damaged parts, increase the damping, improve the spring stiffness and control pressure, etc.