Head suspension with resonance feedback transducer

• US 5,862,015 A
• Filed: 05/22/1997
• Issued: 01/19/1999
• Est. Priority Date: 05/23/1996
• Status: Expired

• Current Assignee: Hutchinson Technology Incorporated (TDK Corporation)
• Original Assignee: Hutchinson Technology Incorporated (TDK Corporation)
• Inventors: Evans, Robert B., Krinke, Todd A.
• Primary Examiner(s): Wolff, John H.
• Application Number:
  US08/861,530
• Time in Patent Office: 607 Days
• Field of Search: 360/104
• US Class Current: 360/244.1
• CPC Class Codes: G11B 5/4833 Structure of the arm assembly, e.g. load beams, flexures, parts of the arm adapted for controlling vertical force on the head G11B5/484 takes precedence

Abstract

A head suspension assembly including a load beam having a rigid region, a mounting region on a proximal end of the load beam, and a flexure on a distal end of the load beam. The flexure has a read/write head attachment region for supporting a read/write head on the distal end of the load beam. Deformation of the head suspension assembly displaces the head attachment region. A strain transducer circuit that acts as a strain gauge is mounted on the head suspension assembly. The resistance of the transducer circuit varies with strain in the circuit, which, in turn, varies with displacement of the read/write head. The magnitude of resistance change of the transducer circuit indicates the magnitude of head off-neutral motion.

Claims

1. A head suspension assembly in which resonance mode motion can induce strain, the head suspension assembly comprising:

a load beam having a proximal end, a distal end, a mounting region on the proximal end, a rigid region adjacent to the distal end and a spring region between the rigid region and the mounting region;

a flexure for supporting a read/write head at the distal end of the load beam; and

at least one strain transducer circuit on the head suspension assembly for detecting strain therein such that the strain transducer circuit detects resonance mode motion of the head suspension assembly.

2. The head suspension assembly of claim 1 wherein the strain transducer circuit is located on the load beam.

3. The head suspension assembly of claim 1 wherein the load beam includes a spring region between the rigid region and the mounting region and further wherein the strain transducer circuit is located in the spring region.

4. The head suspension assembly of claim 1 wherein the strain transducer circuit is located on the rigid region of the load beam.

5. The head suspension assembly of claim 1 wherein the flexure includes a head attachment region for supporting a read/write head at the distal end of the load beam and wherein an elastic deformation of the head suspension assembly can displace the head attachment region from a neutral position and generate strain in the head suspension assembly.

6. The head suspension assembly of claim 5 wherein the strain transducer circuit has an electrical resistance which varies with strain in the head suspension assembly at a position of the strain transducer circuit thereon such that the resistance in the strain transducer circuit varies with deformation of the head suspension assembly to allow detection of motion of the head mounting region out of the neutral position.

7. The head suspension assembly of claim 6 wherein the strain transducer circuit is located on the load beam.

8. The head suspension assembly of claim 6 wherein the strain transducer circuit includes a single strain gauge lead having an electrical resistance that varies with strain on the lead.

9. The head suspension assembly of claim 8 wherein the strain gauge lead is formed of Constantan.

10. The head suspension assembly of claim 5 wherein the strain transducer circuit is located in the spring region.

11. The head suspension assembly of claim 10 including a first strain transducer circuit and a second strain transducer circuit wherein the spring region has an open region that divides the spring region into first and second radius arms and the first strain transducer circuit is located on the first radius arm and the second strain transducer circuit is located on the second radius arm.

12. The head suspension assembly of claim 1 wherein the strain transducer circuit is on the flexure.

13. The head suspension assembly of claim 1 including first, second, third and forth strain transducer circuits wherein the spring region has an open region that divides the spring region into first and second radius arms and the first and second strain transducer circuits are located on the first radius arm, the third and forth strain transducer circuits are located on the second radius arm, and the first, second, third and forth strain transducer circuits are interconnected to form a wheatstone bridge circuit.

14. A head suspension assembly comprising:

a load beam having a proximal end, a distal end, a mounting region on the proximal end, a rigid region adjacent to the distal end and a spring region between the rigid region and the mounting region;

a flexure having a head attachment region for supporting a read/write head and at the distal end of the load beam, the head attachment region displaceable from a neutral position, such displacement causing strain in the head suspension assembly;

a microactuator on the head suspension assembly between the mounting region and the head attachment region and to displace the head attachment region from the neutral position and along a transverse tracking axis; and

at least one strain transducer circuit on the head suspension assembly for detecting strain in the head suspension assembly wherein displacement of the head attachment region from the neutral position caused by the microactuator is detected by the strain transducer circuit.

15. The head suspension assembly of claim 14 wherein the strain transducer in located on the load beam.

16. The head suspension assembly of claim 14 wherein the strain transducer circuit has an electrical resistance which varies with strain in the head suspension assembly at a position of the strain transducer circuit thereon.

17. The head suspension assembly of claim 16 wherein the strain transducer circuit includes a single strain gauge lead having an electrical resistance that varies with strain on the lead.

18. A head suspension assembly in which resonance mode motion can induce strain, comprising:

a load beam having a proximal end, a distal end, a mounting region on the proximal end, a rigid region adjacent to the distal end and a spring region between the rigid region and the mounting region;

an actuator arm having a proximal end and a distal end, the proximal end of the load beam mounted to the distal end of the actuator arm;

a flexure for supporting a read/write head and at the distal end of the load beam; and

at least one strain transducer circuit on the head suspension assembly for detecting strain in the head suspension assembly such that the strain transducer circuit detects resonance frequency vibrations of the head suspension assembly.

19. The head suspension assembly of claim 18 wherein the strain transducer circuit has an electrical resistance which varies with strain in the head suspension assembly at a position of the strain transducer circuit thereon.

20. The head suspension assembly of claim 18 wherein the strain transducer circuit is located on the actuator arm.

21. The head suspension assembly of claim 18 including a first strain transducer circuit and a second strain transducer circuit wherein the first strain transducer circuit is located on the actuator arm and the second strain transducer circuit is located on the load beam.