Abstract
In this paper, we propose a method of noise reduction for a variable displacement axial piston pump of even number of cylinders with two swash angle control cylinders. In the 8-piston pump, two exciting forces act on the upper and lower part of the swash plate at the same time when two of the rota cylinders come to the top and the bottom center respectively. To compensate the exciting moment and reduce the pump noise, the pressure in the upper side rota cylinder is lead to the lower control cylinder, and vice versa, for a short time through small orifices on the valve plate. Determining the orifice diameters properly, the compensating moment could be obtained and the noise level was reduced to 64.5dB from 71 dB under the condition of the delivery pressure of 6.9 MPa and the flow rate of 25l/min.
