Laminate-type piezoelectric element and method of producing the same

• US 7,554,250 B2
• Filed: 12/19/2006
• Issued: 06/30/2009
• Est. Priority Date: 12/19/2005
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Yamaguchi, Teruaki, Kadotani, Shige, Iwase, Akio
• Primary Examiner(s): SanMartin; Jaydi
• Application Number:
  US11/641,121
• Publication Number:
  US 20070164638A1
• Time in Patent Office: 924 Days
• Field of Search: 310363-366
• US Class Current: 310/365
• CPC Class Codes: F02M 63/0026 using piezoelectric or magnetostrictive actuators
• CPC Class Codes: H10N 30/063 Forming interconnections, e.g. connection electrodes of multilayered piezoelectric or electrostrictive parts
• CPC Class Codes: H10N 30/503 with non-rectangular cross-section orthogonal to the stacking direction, e.g. polygonal, circular
• CPC Class Codes: H10N 30/872 Connection electrodes of multilayer piezoelectric or electrostrictive devices, e.g. external electrodes

Abstract

A laminate-type piezoelectric element has a ceramic laminated body obtained by alternately laminating piezoelectric layers made of a piezoelectric material and inner electrode layers having electrical conductivity. Outer electrodes are joined to side surfaces of the ceramic laminated body via an electrically conductive adhesive. The electrically conductive adhesive has buried therein mesh bodies obtained by forming a mesh by using a nonmetallic material. The mesh bodies are desirably constituted by using any one of a resin, ceramic, carbon or glass.

Claims

1. A laminate-type piezoelectric element comprising:

a ceramic laminated body having alternately laminated piezoelectric layers made of a piezoelectric material and inner electrode layers having electrical conductivity, and having outer electrodes joined to the side surfaces of said ceramic laminated body via an electrically conductive adhesive,

wherein said electrically conductive adhesive has buried therein at least parts of a mesh body formed as a mesh including nonmetallic material.

2. A laminate-type piezoelectric element according to claim 1, wherein:

said nonmetallic material in the mesh body comprise at least one of a resin, ceramic, carbon or glass.

3. A laminate-type piezoelectric element according to claim 1, wherein:

said nonmetallic material in the mesh body comprise a knitted fiber of a nonmetallic material.

4. A laminate-type piezoelectric element according to claim 3, wherein:

the fiber is a fiber aggregate obtained by bundling smaller fibers.

5. A laminate-type piezoelectric element according to claim 1, wherein:

the surfaces of said mesh body are covered with an electrically conductive material.

6. A laminate-type piezoelectric element according to claim 5, wherein:

said electrically conductive material contains at least one of Pt, Pd, Ta, Au, Ag, Cu, Ni, Zn and Sn.

7. A laminate-type piezoelectric element according to claim 1, wherein:

said laminate-type piezoelectric element is a piezoelectric actuator for an injector used as a drive source of the injector.

8. A method of producing a laminate-type piezoelectric element having a ceramic laminated body obtained by alternately laminating piezoelectric layers made of a piezoelectric material and inner electrode layers having electrical conductivity, and having outer electrodes joined to the side surfaces of said ceramic laminated body via an electrically conductive adhesive, the method comprising:

forming a ceramic laminated body by alternately laminating piezoelectric layers and inner electrode layers;

applying electrically conductive adhesive to side surfaces of said ceramic laminated body;

burying at least parts of a mesh body formed by using a nonmetallic material in said electrically conductive adhesive; and

joining said external electrodes to said electrically conductive adhesive.

9. A method of producing a laminate-type piezoelectric element according to claim 8, wherein:

said mesh body is made by using at least one of a resin, ceramic, carbon or glass.

10. A method of producing a laminate-type piezoelectric element according to claim 8, wherein:

said mesh body is made by knitting a fiber made of a nonmetallic material.

11. A method of producing a laminate-type piezoelectric element according to claim 10, wherein:

the fiber is a fiber aggregate obtained by bundling smaller fibers.

12. A method of producing a laminate-type piezoelectric element according to claim 8, wherein:

surfaces of said mesh body are covered with an electrically conductive material.

13. A method of producing a laminate-type piezoelectric element according to claim 12, wherein:

said electrically conductive material contains at least one of Pt, Pd, Ta, Au, Ag, Cu, Ni, Zn and Sn.