Simulation and Experimental Research on Composite Diaphragm Hydraulic Force/Displacement Amplification Mechanism with Adjustable Initial Volume

To improve the practicability of electro-mechanical converters in hydraulic systems, especially in control valves, a hydraulic force/displacement amplification mechanism was addressed. The amplification mechanism includes a rolling diaphragm (RD) and a corrugated diaphragm (CD), and the amplification function is achieved using the area difference between the RD and the CD. To investigate the amplification characteristics of the mechanism, the diaphragm forces were analyzed by finite element simulations, and the dynamic model of the system was established in Simulink, based on the force balance method. Furthermore, an amplification mechanism prototype was fabricated, and the static and dynamic experiments were carried out. Combining the simulation and experiment results, the accuracy of the proposed dynamic model was verified, and the amplification characteristics of the amplification mechanism were analyzed. When the RD displacement is less than 2 mm, the force amplification effect is not obvious. When the RD displacement exceeds 2 mm, the force amplification ratio (FAR) increases with the RD displacement and decreases with the CD displacement. The maximum FAR is 2.5 with a CD displacement of 0 and an RD displacement of 6 mm. The amplification mechanism and the used research method are helpful for the application and control of the hydraulic valves.