Laminated piezoelectric actuator

• US 5,208,506 A
• Filed: 11/13/1991
• Issued: 05/04/1993
• Est. Priority Date: 11/14/1990
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Yamashita, Osamu
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): LABALLE, CLAYTON E
• Application Number:
  US07/791,433
• Time in Patent Office: 538 Days
• Field of Search: 310/328, 310/344, 310/348, 310/366
• US Class Current: 310/328
• CPC Class Codes: H10N 30/50 having a stacked or multilayer structure
• CPC Class Codes: H10N 30/88 Mounts; Supports; Enclosures; Casings

Abstract

A laminated piezoelectric actuator includes a plurality of electrostrictive elements which are connected with each other. Each element 1 is a structure alternately laminated with electrostrictive material layers and internal electrode layers. The elements are sealed in an enclosure consisting of a metallic casing 5 with at least one metallic member 3 and 6 fixed to an aperture of the casing 5. The actuator has a supporting member 7 for connecting and positioning the elements 1 in their longitudinal displacing direction. The supporting member 7 has a notch formed on its opposed lateral surfaces which provides an exit for leads connected to the plurality of electrostrictive affect elements. In the actuator, even if the voltage is repeatedly turned on and off, the electrostrictive material layer will not crack and the connecting portion cannot slip off.

Claims

1. A laminated piezoelectric actuator comprising:

a plurality of piezoelectric actuator units housed in an insulating case having a pair of elongated slits in a wall thereof, each of said actuator units being stacked free of an adhesive agent therebetween, each of said actuator units having a pair of lead wires, all of said lead wires passing through a said pair of elongated slits, a hermetically sealed metal case housing said actuator units and said insulating case, said metal case having a pair of external terminals connected to a plurality of pairs of said lead wires within a space between an outer surface of said insulating case and an inner wall of said metal case.

2. A laminated piezoelectric actuator as claimed in claim 1, wherein said supporting member comprises a plurality of blocks, each of said blocks having a length which is substantially the same as the length of a single actuator unit and having a protrusion on at least some of four corners of its one end surface and a hole in at least some of four corners of the other end surface, and said blocks being connected to each other by sequentially fitting said protrusion to said hole of an adjacent block.

3. A laminated piezoelectric actuator comprising:

a plurality of electrostrictive elements stacked relative to each other, each of said elements having a structure comprising alternately laminated electrostrictive material layers and internal electrode layers, an enclosure for sealing said elements, said enclosure comprising a metallic casing with at least one metallic member fixed to an aperture in said casing, and a supporting member for stacking said plurality of electrostrictive effect elements in their longitudinally displaced direction, said supporting member having a notch formed on its opposed lateral surfaces for providing an exit for leads connected to said plurality of electrostrictive effect elements, and said supporting member comprises a plurality of blocks, each of said blocks having a length which is substantially the same as the length of a single element and having a protrusion at each of four corners of its one end surface and a hole at each of four corners of the other end surface so as to be connected to each other by sequentially fitting said protrusion to said hole of an adjacent block.