The characteristics of pressure ripple in variable displacement vane pumps: comparison between theory and experiment

This paper reports on the theoretical and experimental study on the discharge pressure ripples in a variable displacement vane pump. The pressure ripple in the delivery port is caused by flow ripple, which is induced by variation of pumping chamber volume. The other reason is the reverse flow from the outlet volume produced by the pressure difference between the pumping chamber and the outlet volume when the pumping chamber is connected to the outlet volume. In this study, a mathematical model is presented for analysing discharge pressure ripple, which includes vane detachment, cam ring movement and fluid inertia effects in a V-groove in the side plate. The model is applied to predict the level and the waveform of the discharge pressure ripples for various operating conditions. An experiment was per-formed to verify the theoretical analysis. The theoretical results provided in this study show a good agreement with the experimental results. This analytical model can predict the magnitude of discharge pressure ripple in variable displacement vane pumps and thus is useful for achieving optimal design of vane pumps.