Piezoelectric actuator unit

• US 6,984,924 B1
• Filed: 08/05/1999
• Issued: 01/10/2006
• Est. Priority Date: 08/06/1998
• Status: Expired due to Term

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Siemens AG
• Inventors: Voigt, Andreas, Frank, Wilhelm, Zumstrull, Claus, Lewentz, Günter
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US09/529,010
• Time in Patent Office: 2,350 Days
• Field of Search: 310/325, 310/328, 310/338, 310/340, 310/345, 310/346, 310/348
• US Class Current: 310/348
• CPC Class Codes: F02M 2200/50 Arrangements of springs for valves used in fuel injectors or fuel injection pumps
• CPC Class Codes: F02M 63/0026 using piezoelectric or magnetostrictive actuators
• CPC Class Codes: F16F 1/028 cylindrical, with radial openings
• CPC Class Codes: F16F 2224/0283 piezoelectric; electro- or magnetostrictive
• CPC Class Codes: H02N 2/043 Mechanical transmission means, e.g. for stroke amplification

Abstract

An actuator unit has an elastically configured hollow body in which a piezoelectric actuator is biased, the hollow body being provided with holes which are of a dumb-bell shape and run transversely of the hollow body'"'"'s axis.

Claims

1. An actuator unit comprising:

a piezoelectric actuator;

contact pins arranged along the actuator conductive connection with said actuator; and

a hollow body having the piezoelectric actuator disposed therein, said hollow body being elastic and biasing the actuator, wherein the hollow body is joined tensionally and/or positively to upper and lower ends of the actuator, said hollow body having holes therein of a dumb-bell shape running transversely of the hollow body'"'"'s axis.

2. The actuator unit according to claim 1, wherein the piezoelectric actuator is gripped in its direction of expansion between upper and lower cover plates tensionally and/or positively joined to the hollow body.

3. The actuator unit according to claim 1, wherein the holes are arranged in rows one above the other, the holes of the rows being laterally offset from one another.

4. The actuator unit according to claim 3, wherein the minimum distance between adjacent holes of two rows is one or three times the wall thickness of the hollow body.

5. The actuator unit according to claim 1, wherein the holes are distributed uniformly over the circumference of the hollow body.

6. The actuator unit according to claim 1, wherein the hollow body is made of steel and the holes are punched holes.

7. The actuator unit according to claim 1, wherein the hollow body has at least one weld seam joining together two abutting edges of the hollow body.

8. The actuator unit according to claim 1, wherein the hollow body has two abutment edges associated with one another extending and over the length of the hollow body.

9. The hollow body according to claim 1, wherein the holes are distributed uniformly over the circumference of the hollow body.

10. The hollow body according to claim 1, wherein the hollow body is made of spring steel and the holes are punched.

11. The hollow body according to claim 1, wherein the hollow body has at least one weld seam which joins together two abutting edges of the hollow body.

12. The hollow body according to claim 1, wherein the hollow body has two abutment edges which are associated with one another and extend over the entire length of the hollow body.

13. The actuator unit of claim 1, wherein the hollow body comprises a tubular spring.

14. The actuator unit of claim 1, wherein the holes of a dumb-bell shape each comprise two side-by-side circular holes joined together by a slot.

15. The actuator unit of claim 14, wherein the circular holes range from about 0.8 to 1.6 mm in diameter.

16. The actuator unit of claim 14, wherein the centers of two circular holes connected by a slot are separated by a distance in a range from 1.5 to 3.5 mm.

17. The actuator unit of claim 13, wherein the hollow body is comprised of spring steel.

18. The actuator of claim 13, wherein the hollow body is comprised of copper-beryllium alloy.