Piezoelectric hydraulic pump

A hybrid piezohydraulic pump is under development for smart structures applications. Structural control applications often require large force be delivered over a large displacement. Piezoelectric actuators produce a large force over a small displacement. This can be repeated many times per second. Step and repeat piezoelectric devices, such as inchworm motors, increase the power output of the actuators and have the potential to produce large forces and large displacements simultaneously. The piezohydraulic pump makes use of the step and repeat capability. The pump utilizes a piezoelectric stack actuator to drive a piston in a cylinder. The forward stroke pressurizes the hydraulic fluid in the cylinder and forces it out through a check valve. The reverse stroke draws fluid into the cylinder through a second check valve. The prototype pump has produced a working pressure of 6.9 MPa (1000 psi) and a flow rate of 45 ccm.