Design, Simulation and Test of High-flow High-speed on/off Valve Driven by Piezoelectric

： A piezoelectric (PZT) direct-acting high-speed switching valve is designed in order to improve the lack of rapidity and large flow. In view of the fast response of PZT crystal, the PZT actuator is used to drive the conical valve core structure directly, which open and close the on/off valve. A bridge-type displacement amplification structure is designed to amplify the displacement output of PZT actuator, which increases the control flow of the switching valve. A combined structure of cone valve and slide valve is proposed to compensate the hydrodynamic fluctuation during the opening and closing process of PZT switching valve. The hydrodynamic model is established to analyze the change of fluid load force. The mathematical model of PZT high-speed on/off valve is established, and the design parameters affecting its performance are analyzed and optimized by AMESim simulation software. The test platform for static flow rate and dynamic open-close characteristics of PZT high-speed on/off valve is built. The PWM driving and control methods are studied based on the performance indexes such as flow characteristics, opening and closing time. The relationship between carrier frequency, duty cycle and static, dynamic flow of on-off valve is analyzed. The simulation and experimental results based on the prototype and design parameters show that the designed PZT on/off valve has a flow rate of 17.4 L/min, an opening time of 1.05 ms and a closing time of 0.85 ms at the pressure of 10 MPa. The requirement of high speed and large flow is realized. The research work provides a theoretical basis for the accurate flow control of high speed on/off valve and is of great significance for the application of digital hydraulic technology.