Abstract
This paper deals with active noise control of a variable displacement swash plate type axial piston pump. The primary cause of noise generation of a piston pump is the exciting force due to sudden pressure change in the rotor cylinders. We tried a new method to compensate the pump exciting force by activating two built-in control cylinders using an electro-hydraulic servo valve and sinusoidal signals synchronous with the pump rotation. This method is not to suppress the exciting force itself but to prevent it from vibrating the pump and consequently to reduce the peak level of frequency components of the pump noise. Through the experiments, the exciting force compensation has been verified to be effective for noise reduction of a pump. The noise level could be reduced, for example, to 68 dB from 74 dB for the pump equipped with rubber vibration isolators, and to 70 dB from 82 dB without isolators.
