Piezoelectric actuator, especially multilayer ceramic piezo-actuator used as positioning device, ultrasonic emitter, valve controller or sensor

摘要

The piezoelectric actuator has a helically wound layer sequence (1), in which piezoelectric layer extension occurs roughly parallel to the linear helix winding axis. The piezoelectric actuator has a layer sequence (1) comprising a piezoelectric layer, sandwiched between two electrode layers (6, 7), and a further layer, the layer sequence being wound as a helix about a linear axis such that, on applying a voltage between the electrode layers, extension of the piezoelectric layer occurs in a helix region roughly parallel to the linear axis. Independent claims are also included for the following: (i) production of the above piezoelectric actuator by cutting a cylinder of ceramic or electrode material to form two interposed helices and then introducing electrode or ceramic material into the cut grooves between the helices; (ii) production of the above piezoelectric actuator by extrusion of the individual layers to produce a helical layer sequence; (iii) an apparatus for carrying out process (ii), comprising an extrusion unit with a combination of nozzles for simultaneously producing the layers of the actuator; and (iv) production of the above piezoelectric actuator by subjecting a foil of the layers to stamping to form annular discs with an additional radial cut edge and then twisting and stacking the discs to form a helix.