There is provided an actuator utilizing a piezoelectric transducer that is structured in small size by feeding the electrical power to the internal surface to the piezoelectric transducer formed in the cylindrical shape. The electrodes are formed to both front and rear surfaces of a sheet type piezoelectric element and this element is wound in the cylindrical shape. The cylindrical material is normalized under the predetermined temperature and a voltage is applied across the electrodes for the polarization purpose. An electrode terminal having the contactors is inserted to the internal surface of the piezoelectric transducer formed in the cylindrical shape and the contactors are placed in contact with the electrodes exposed at the internal surface of the cylindrical shape for the purpose of power feeding.
A stacked piezoelectric element comprising that can suppress periodic damping on miniaturization of a vibration wave motor and improve its performance. A stacked piezoelectric element comprises piezoelectric layers and electrode layers alternately stacked to have a shape of a cylinder. The electrode layers are divided into a plurality of electrode layer regions along a circumferential surface of the shape of a cylinder.
An electrical connector arrangement for a piezoelectric actuator (10) having a stack (26) of one or more piezoelectric elements, the electrical connector arrangement including positive and negative terminals (30, 32) for connection with distribution electrodes (44a, 44b) of the piezoelectric stack (26). Each of the positive and negative terminals (30, 32) has a lower end face (30d, 32d) which locates adjacent to an upper end face of the stack (26), in use, and a radially outer contact face (30e, 32e) for contact with the distribution electrodes (44a, 44b). The terminals (30, 32) also connect with an external voltage supply, in use. A block (30c, 32c) of each terminal (30, 32) defines the radially outer contact face (30e, 32e) for the stack distribution electrodes (44a, 44b) and thus provides a robust terminal structure.
A composite piezoelectric transducer, whose piezoeletric element is a "ribbon wound" film of piezolectric material. As the film is excited, it expands and contracts, which results in expansion and contraction of the diameter of the entire ribbon winding. This is accompanied by expansion and contraction of the thickness of the ribbon winding, such that the sound radiating plate may be placed on the side of the winding.
The invention describes rolled electroactive polymer devices. The invention also describes employment of these devices in a wide array of applications and methods for their fabrication. A rolled electroactive polymer device converts between electrical and mechanical energy; and includes a rolled electroactive polymer and at least two electrodes to provide the mechanical/electrical energy conversion. Prestrain is typically applied to the polymer. In one embodiment, a rolled electroactive polymer device employs a mechanism, such as a spring, that provides a force to prestrain the polymer. Since prestrain improves mechanical/electrical energy conversion for many electroactive polymers, the mechanism thus improves performance of the rolled electroactive polymer device.
A tubular elastomer actuator with a shape in a cross-sectional view which shape exposes at most one single axis of symmetry of a specific length, e.g. an oval shape. The actuator could be made from a sheet made from a plurality of plate shaped elements which are laminated together and rolled. Each plate shaped element may have a corrugation that gives the element an anisotropic structure, and contains an electrode on only one surface. The actuator displacement is the result of shrinkage displacement of the plate shaped elements upon the application of electrical field across their thickness.
