Multilayer disk drive motors having out-of-plane bending

Patent metadata

Field	Value
Publication number	US-9318136-B1
Application number	US-201414579063-A
Country	US
Kind code	B1
Filing date	Dec 22, 2014
Priority date	Dec 22, 2014
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

Various embodiments concern a gimbaled flexure having a dual stage actuation structure. The flexure comprises a gimbal on which a motor is mounted. The motor comprises a first and second terminals and a plurality of actuator layers formed from a piezoelectric material. The plurality of actuator layers comprise serially stacked first, second, and third actuator layers. The plurality of actuator layers are respectively poled and connected to the first and second terminals such that both of the first and second actuator layers expand while the third actuator layer contracts in response to application of a signal across the first and second terminals. The differential motion of the plurality of layers in the motor cause the motor to curl about the contracting third actuator layer. The curling motion causes a portion of the flexure to preferentially curl.

First claim

The following is claimed:

1. A suspension structure, comprising:
a flexure; and
a motor mounted on the flexure, the motor comprising a first terminal, a second terminal, and a plurality of actuator layers formed from a piezoelectric material, the plurality of actuator layers consisting of a first set having multiple actuator layers and a second set having one or more actuator layers, the first set having a greater number of actuator layers than the second set, the first set comprising a first actuator layer and a second actuator layer adjacent to the first actuator layer, the second set comprising a third actuator layer adjacent to the second actuator layer, the plurality of actuator layers respectively poled and connected to the first and second terminals such that the multiple actuator layers of the first set one of expand or contract while the one or more actuator layers of the second set the other of expands or contracts in response to application of a signal having a first polarity across the first and second terminals, wherein the actuator layers of the first set cause longitudinal expansion or contraction of the motor while the one or more actuator layers of the second set cause the motor to at least partially curl upon the application of the signal having the first polarity.

2. The suspension structure of claim 1 , wherein the first and second actuator layers are poled in a first orientation while the third actuator layer is poled in a second orientation that is different from the first orientation.

3. The suspension structure of claim 2 , wherein the first orientation is opposite the second orientation.

4. The suspension structure of claim 1 , wherein the plurality of actuator layers are positioned in a stacked arrangement.

5. The suspension structure of claim 1 , wherein the motor further comprises a plurality of conductive layers, the plurality of conductive layers formed from metal and interleaved with the plurality of actuator layers.

6. The suspension structure of claim 1 , further comprising a circuit at least partially located on the flexure, the circuit configured to apply the signal across the first and second terminals.

7. The suspension structure of claim 6 , wherein the circuit is further configured to reversibly switch the polarity of the signal to a second polarity, and the plurality of actuator layers are respectively poled and connected to the first and second terminals such that both of the second and third actuator layers one of expand or contract while the first actuator layer the other of expands or contracts in response to application of the signal having the second polarity across the first and second terminals.

8. The suspension structure of claim 1 , wherein the plurality of actuator layers are electrically connected to one another in a parallel arrangement.

9. The suspension structure of claim 1 , wherein the flexure further comprises a tongue having a slider mounting, wherein the signal causes the tongue to rotate about a tracking axis.

10. The suspension structure of claim 1 , wherein the motor is limited to five or fewer piezoelectric actuator layers.

11. The suspension structure of claim 1 , wherein the flexure comprises a gimbal and the motor is mounted on the gimbal.

12. A suspension structure, comprising:
a flexure; and
a motor mounted on the flexure, the motor comprising:
a first terminal;
a second terminal;
a plurality of actuator layers formed from a piezoelectric material, the plurality of actuator layers comprising a first actuator layer, a second actuator layer, and a third actuator layer, wherein the motor does not contain any layers formed from the piezoelectric material other than the first, second, and third actuator layers; and
a plurality of conductive layers, the plurality of conductive layers comprising a first conductive layer disposed on a top side of the first actuator layer, a second conductive layer located between and in contact with the first actuator layer and the second actuator layer, a third conductive layer located between and in contact with the second actuator layer and the third actuator layer, and a fourth conductive layer disposed on a bottom side of the third actuator layer,
wherein the first and third conductive layers are directly connected to the second terminal and the second and fourth conductive layers are directly connected to the first terminal, and
wherein the first and second layers are both poled in a first orientation and the third layer is poled in a second orientation different from the first orientation, and
wherein both of the first and second actuator layers one of expand or contract while the third actuator layer the other of expands or contracts and the motor curls in response to application of a signal having a first polarity across the first and second terminals.

13. The suspension structure of claim 12 , wherein both of the second and third actuator layers one of expand or contract while the first actuator layer the other of expands or contracts and the motor curls in response to application of the signal having a second polarity that is different from the first polarity across the first and second terminals.

14. The suspension structure of claim 13 , further comprising a circuit at least partially located on the flexure, the circuit configured to apply the signal across the first and second terminals.

15. The suspension structure of claim 12 , wherein the first orientation is opposite the second orientation.

16. A suspension structure, comprising:
a flexure; and
a motor mounted on the flexure, the motor comprising a first terminal, a second terminal, and a plurality of actuator layers formed from piezoelectric material, the plurality of actuator layers comprising a first set of actuator layers and a second set of actuator layers fewer in number of the first set, the first set comprising multiple actuator layers and the second set comprising one or more actuator layers, the first and second sets of actuator layers together comprising the only piezoelectric material of the motor, the plurality of actuator layers respectively poled and connected to the first and second terminals such that the multiple actuator layers of the first set one of expands or contracts while the one or more actuator layers of the second set the other of expands or contracts in response to application of a signal having a first polarity across the first and second terminals, wherein the multiple actuator layers of the first set cause longitudinal expansion or contraction of the motor while the one or more actuator layers of the second set cause the motor to at least partially curl in response to application of the signal having the first polarity.

17. The suspension structure of claim 16 , wherein the plurality of actuator layers comprises only five actuator layers.

18. The suspension structure of claim 16 , wherein the motor comprises only three actuator layers.

Assignees

• Hutchinson Technology

Inventors

• Bjorstrom Jacob D
• Ruzicka Ryan N
• Wheatley Joseph C

Classifications

• G11B5/5552

  using fine positioning means for track acquisition separate from the coarse (e.g. track changing) positioning means · CPC title

• G11B5/4873 Primary

  the arm comprising piezoelectric or other actuators for adjustment of the arm · CPC title

• G11B5/483 Primary

  Piezoelectric devices between head and arm, e.g. for fine adjustment · CPC title

• G11B5/4826

  Mounting, aligning or attachment of the transducer head relative to the arm assembly, e.g. slider holding members, gimbals, adhesive (G11B5/484 takes precedence; details of head housings or structures G11B5/10, G11B5/127; adjustment relative to the record carrier G11B5/56) · CPC title

• G11B5/4853

  Constructional details of the electrical connection between head and arm · CPC title