Basic investigations of electrohydraulic servovalve with piezo-bender element

One of possible solution is usage of piezo-benders as control elements for hydraulic or pneumatic valves [1, 2, 3, 4]. It small dimensions assure reduction of movable mass and enables getting better of dynamic parameters. Usable deflections and blocking forces obtained from piezoelements can be sufficient to fit requirements for servovalve control stages [5, 6]. Cost of today produced piezoelements (about 50÷70 EUR) seems to be also acceptable for mass applications. Because bending of piezo-beam is relevant to applied voltage they can be used as a flapper plate between two nozzles inside the control stage of servovalve.