Cylinder Pressure Transients in Oil Hydraulic Pumps with Sliding Plate Valves

This paper reports an experimental study of the cylinder pressure within an axial piston pump. This study revealed that existing theoretical models, which are based on the effects of fluid compliance within the cylinder, are highly inaccurate at high speeds or high loads. Fluid momentum at the point of port opening was found to be of considerable importance and an improved digital computer model was developed as an aid to pump design. The inclusion of fluid momentum effects resulted in a significant improvement in the agreement between theory and experiment. Cavitation within the cylinder bore was predicted at both high speed and high load conditions; this was confirmed experimentally. The theoretical approach is applicable to any sliding valve plate unit.