Quieter Hydraulic Systems-Design Considerations

Abstract

The noise from hydraulic systems is highly correlated to the system pressure ripple, appearing as a response to introduced flow transients. One of the main origins for flow transients is the hydrostatic pump. In order to reduce the pump generated flow ripple magnitude and its frequency content, several design features have been developed. However, even though they may have very good influences on the flow ripple, their sensitivities to changes in operational conditions are considerable. This implies that a pump optimised for minimizing flow ripple at one specific operational condition, may give severe flow ripple as the conditions are changed. When choosing a design feature for a pump, it is important that the pump behaves satisfactory throughout the whole range of operational conditions. It is therefore necessary to be aware of the plausible conditions to which the pump will be exposed.In this paper, the sensitivities for changes in the operational conditions are analysed for three different design features. The insensitivities to operational conditions toghether with over-all flow ripple reductions in relation to implementation cost for different design features is a fair figure of merit, enabling mutual comparisons to be made.