Study on Flutuation Factors of Leakage in a Vane Pump.

A vane pump, composed of a cam ring, rotor, vanes and so on, is compact and low cost, and is widely used in hydraulic systems. In the vane pump, the reduction of pressure pulsations is required. It is known that pressure pulsations are caused by delivery flow variations which depend on changes of leakage flow as well as the theoretical displacement at different rotational angles. The leakages flow not only through clearances at the sides of the rotor and vanes but also through clearances between the rotor slits and vanes. In the past, although the leakage flow in the vane pump was analyzed, the leakage flow through the clearances between the rotor slits and vanes was not taken into consideration. This has caused disagreement in results of theoretically calculated leakage flow with experimental ones.This paper deals with the leakage flows through various clearances, especially those between the rotor slits and vanes. In this study, in an attempt to investigate the leakage through the clearance between the rotor slit and vane, the postures of the vanes were visually observed. It was noticed that the vane at the pump suction port clings to the side wall of rotor slit. This phenomenon led us to believe that leakage flow through the slit clearance exists.On the basis of the observation results, the leakage flows through various clearances were calculated theoretically and compared with the experimental results. The measured leakage flows correspond closely to theoretically calculated values taking account of the leakage flow at the rotor slit part.