Construction for transmitting displacement of piezoelectric element

• US 6,661,159 B2
• Filed: 07/17/2002
• Issued: 12/09/2003
• Est. Priority Date: 07/18/2001
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Yamada, Yutaka
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US10/196,276
• Publication Number:
  US 20030015939A1
• Time in Patent Office: 510 Days
• Field of Search: 310/323.13, 310/328, 310/329
• US Class Current: 310/328
• CPC Class Codes: F02M 2200/21 Fuel-injection apparatus with piezoelectric or magnetostrictive elements
• CPC Class Codes: H10N 30/50 having a stacked or multilayer structure
• CPC Class Codes: H10N 30/88 Mounts; Supports; Enclosures; Casings

Abstract

Structure for transmitting displacement of a piezoelectric element includes a piston member. A distal-end plate portion has a receiving face adapted to be brought into direct contact with a distal-end face of the piston member. The distal-end face of the piston member is brought into direct contact with a mating member at a displacement transmitting face which is situated on an opposite side to the receiving face. End faces of a piezoelectric element in a displacement direction are maintained substantially in parallel to each other while the piezoelectric element is being driven. The contact configuration between the distal-end face and the receiving face is an annular and linear contact condition, whereby the piezoelectric element, the piston member and the distal-end plate portion are constructed so as to remain substantially stationary while the piezoelectric element is being driven.

Claims

1. A structure for transmitting the displacement of a piezoelectric element which is constructed in such a manner as to transmit to a mating member a displacement generated in a stacked piezoelectric element when said stacked piezoelectric element is energized to be driven, said structure for transmitting the displacement of a piezoelectric element comprising:

a piston member which is in direct contact with said piezoelectric element and is disposed at one end face of said piezoelectric element in a displacement direction thereof, and

a distal-end plate portion which has a receiving face in direct contact with a distal-end face of said piston member in the displacement direction of said piezoelectric element and which is adapted to be brought into direct contact with a mating member to be driven at a displacement transmitting face thereof which is situated on an opposite side to said receiving face;

wherein both end faces of said piezoelectric element in the displacement direction thereof are maintained substantially in parallel with each other;

wherein an in-line annular contact configuration exists between said distal-end face of said piston member and said receiving face of said distal-end plate portion; and

wherein said piezoelectric element, said piston member and said distal-end plate portion are constructed to include only one annular contact interface and to be substantially stationary relative to directions except for the displacement direction of said piezoelectric element.

2. A structure for transmitting the displacement of a piezoelectric element as set forth in claim 1, wherein:

one of said distal-end face of said piston member and said receiving face of said distal-end plate portion comprises a conical concave surface; and

the other one of said receiving face of said distal-end plate portion and said distal-end face of said piston member comprises a hemispherical convex surface.

3. A structure for transmitting the displacement of a piezoelectric element as set forth in claim 2, wherein the contact configuration between said distal-end face of said piston member and said receiving face of said distal-end plate portion is an annular oval, and wherein a major diameter of said annular contact configuration has a length which is at least 50% longer than that of one of major diameters of said hemispherical convex surface and said conical concave surface in said distal-end face and said receiving face.

4. A structure for transmitting the displacement of a piezoelectric element as set forth in claim 2, wherein the contact configuration between said distal-end face of said piston member and said receiving face of said distal-end plate portion is an annular oval, and wherein a major diameter of said annular contact configuration has a length which is no more than 90% of one of major diameters of said hemispherical convex surface and said conical concave surface in said distal-end face and said receiving face.

5. A structure for transmitting the displacement of a piezoelectric element as set forth in claim 3, wherein the contact configuration between said distal-end face of said piston member and said receiving face of said distal-end plate portion is an annular oval, and wherein a major diameter of said annular contact configuration has a length which is no more than 90% of one of major diameters of said hemispherical convex surface and said conical concave surface in said distal-end face and said receiving face.

6. A structure for transmitting the displacement of a piezoelectric element as set forth in claim 1, wherein said displacement transmitting face of said distal-end plate portion comprises a flat plane.

7. A structure for transmitting the displacement of a piezoelectric element as set forth in claim 1, in combination with a fuel injector providing said mating member to be driven.