Abstract
This paper deals with an active noise control of a variable displacement axial piston pump. The primary cause of noise generation of a piston pump is the exciting force due to the sudden pressure change in the rotor cylinders. In the pump with even number of cylinders, it is easy to control the vibration because exciting forces make a moment and the frequency is a half of that of the pump with odd number of cylinders. We use two swash angle control cylinders to actively control the swash plate vibration and reduce the pump noise. This methodis not to suppress the vibration but to support the swash plate softly and consequently to reduce the high frequency components of the pump noise. The noise level was reduced to 67 dB from 69 dB and the effects remained for a long time after once the parameters were tuned.
