Study on a piezohydraulic pump for linear actuators

Abstract

To obtain high flowrate and pressure, a piezostack pump with stiffened chamber diaphragm (consisting of a membrane and rigid disk) was presented and studied. An analytical model for performance evaluation is established based on the theory of plate and shells. The effect of chamber diaphragm parameters on flowrate, pressure and output energy coefficient, and that of external load on flowrate and output energy coefficient were analyzed. Considering the influence of the diaphragm stiffness on dynamic–response performance of the piezostack actuator, the design method was introduced. Analysis results show that all of the flowrate, backpressure and output energy coefficient increase with the decreasing of membrane thickness. There is an optimal radius ratio (rigid-disk radius to membrane radius) for flowrate and pressure to achieve peak value, which decreases with the raising of the membrane thickness. On the other hand, output energy coefficient, which decreases with the increasing of radius ratio, achieves peak when force ratio (external load to blocked force of piezostack) is 0.5. At stiffness match and optimal load, maximal output energy coefficient is independent of membrane thickness, and flowrate decreases with the increasing of membrane thickness. To examine analytical results, a check-valve piezostack pump was fabricated and tested. The experiment results show that the flowrate can be enhanced with optimizing rigid disk.