Piezoelectric actuator

• US 4,928,030 A
• Filed: 09/30/1988
• Issued: 05/22/1990
• Est. Priority Date: 09/30/1988
• Status: Expired due to Term

• Current Assignee: Teledyne Licensing, LLC
• Original Assignee: Rockwell International Corporation
• Inventors: Culp, Gordon W.
• Primary Examiner(s): Budd, Mark O.
• Application Number:
  US07/252,197
• Time in Patent Office: 599 Days
• Field of Search: 310/328, 310/323, 310/316, 310/317
• US Class Current: 310/328
• CPC Class Codes: H02N 2/0095 producing combined linear and rotary motion, e.g. multi-direction positioners
• CPC Class Codes: H02N 2/021 using intermittent driving, e.g. step motors, piezoleg motors
• CPC Class Codes: H02N 2/028 along multiple or arbitrary translation directions, e.g. XYZ stages
• CPC Class Codes: H02N 2/101 using intermittent driving, e.g. step motors
• CPC Class Codes: H02N 2/108 around multiple axes of rotation, e.g. spherical rotor motors
• CPC Class Codes: H02N 2/142 Small signal circuits; Means for controlling position or derived quantities, e.g. speed, torque, starting, stopping, reversing
• CPC Class Codes: H10N 30/1071 with electrical and mechanical input and output, e.g. having combined actuator and sensor parts
• CPC Class Codes: H10N 30/2023 having polygonal or rectangular shape

Abstract

A piezoelectric device or actuator (30) includes dimorph stack (32) attached to a support (34). Affixed to the apex of stack (32) is friction surface (36) which is held in contact with the external friction surface of a positionable object (38).

Claims

1. A piezoelectric device configured to apply a force to an object, said device comprising:

(1) a crown having a friction surface which surface is proximate an object;

(2) a bottom having a surface supported by a support structure;

(3) at least one piezoelectric shear body integrally located intermediate said crown and said bottom;

(4) sensing means for determining the relative position of the crown in relation to the position of said supported surface;

(5) means for adjusting the proximate position, of the crown and the object;

(6) means for detecting and measuring a physical contact force between the crown and said object; and

(7) means for effecting an electric potential within said piezoelectric device to activate same and apply velocity and acceleration forces to said object.

2. The piezoelectric device of claim 1 wherein said means for adjusting the proximate position of the crown and the object further comprise:

(1) piezoelectric shear orthogonally directional tangential actuating portions;

(2) a piezoelectric lifter portion for maintaining the normal force at a desired value despite changes in the geometry of the object and changes in the geometry of said device.

3. The piezoelectric device of claim 1 wherein said means for detecting and measuring a physical contact force between the crown and the object comprises:

(1) piezoelectric compression transduction portion;

(2) piezoelectric shear orthogonally directional sensor portions; and

(3) non-contacting orthogonally directional crown tangential position detection means.

4. The piezoelectric device of claim 1 wherein said means for effecting an electric potential within said device to activate same and apply a force to said object comprises:

(1) controlling means; and

(2) an electric charge source.

5. The piezoelectric device of claim 1 having a pyramidal structure.

6. The piezoelectric device of claim 1 wherein said object is a bar-like object.

7. The piezoelectric device of claim 1 wherein said object is a disk-like object.

8. The piezoelectric device of claim 1 wherein said object is a mirror.

9. The piezoelectric device of claim 1 wherein said object is a lens.

10. The piezoelectric device of claim 1 wherein said object is an optical grating.

11. The piezoelectric device of claim 1 wherein said object is a cone-like object.

12. The piezoelectric device of claim 1 wherein said object is spherical.

13. The piezoelectric device of claim 1 wherein said object is a slab-like object.

14. The piezoelectric device of claim 1 wherein said object is a circuit mask.

15. The piezoelectric device of claim 1 wherein said object is an optical microscope sample.

16. The piezoelectric device of claim 1 wherein said object is a tunnelling electron microscope sample.

17. The piezoelectric device of claim 1 wherein said object is a wheel.

18. Wherein the piezoelectric device of claim 1 is a bearing.

19. The piezoelectric device of claim 6 wherein the piezoelectric lifter portion further comprises at least two dimorphs having grounded electrodes and activate electrodes parallel to a desired direction of lifter translation.

20. An electric motor comprising:

(1) a rotatable and translatable shaft including a shaft surface;

(2) piezoelectric actuators associated with said shaft, said actuators further comprising;

(a) at least one piezoelectric body including a crown having a friction surface which surface is proximate said shaft friction surface, and a bottom having a surface supported by a support structure;

(b) sensing means for determining the position of the crown surface relative to said support structure;

(c) means for adjusting the position of the crown friction surface relative to said shaft, friction surface;

(d) means for detecting and measuring a physical contact force between the crown friction surface and said shaft; and

(e) means for activating said actuators,

(3) linear amplifiers acting tangential to the shaft;

(4) lifter amplifiers acting normal to the shaft surface; and

(5) means for effecting an electric potential within said actuators to activate said shaft of said motor.

21. The electric motor of claim 20 wherein said means for adjusting the position of the crown friction surface relative to said shaft further comprises:

(1) a piezoelectric shear portion acting tangential to the shaft surface;

(2) a piezoelectric shear portion acting axial to the shaft surface;

(3) a lifter piezoelectric portion acting radial to the shaft surface for maintaining the normal force at a desired value despite changes of geometry of the shaft.

22. The electric motor of claim 20 wherein said means for detecting and measuring a physical contact force between the crown and the shaft comprises:

(1) a piezoelectric compression transducer portion to detect forces normal to the shaft;

(2) a piezoelectric shear transducer portion to detect force tangential to the shaft;

(3) a piezoelectric shear transducer portion to detect force axial to the shaft;

(4) a non-contacting crown position detecting means to detect crown position tangential to the shaft; and

(5) a non-contacting crown position detecting means to detect crown position axial to the shaft.

23. The electric motor of claim 20 wherein said means for effecting an electrical potential within said motor to activate same and apply a force to said shaft comprises:

(1) controlling means; and

(2) an electric charge source.