Low-profile ball screw cam elevator mechanism for cold storage data storage device

Patent metadata

Field	Value
Publication number	US-10902871-B2
Application number	US-201916513611-A
Country	US
Kind code	B2
Filing date	Jul 16, 2019
Priority date	Jul 19, 2018
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

An approach to a reduced-head hard disk drive (HDD) involves an actuator subsystem that includes a ball screw cam assembly wherein the number of starts of a multi-start screw equals the number of balls riding in a corresponding start. A stepper motor may be disposed within the screw, to drive rotation of the screw, which drives translation of an actuator arm assembly so that a corresponding pair of read-write heads can access different magnetic-recording disks of a multiple-disk stack. The actuator subsystem may further include a cam locking mechanism for coupling and decoupling the actuator arm with a coil support structure and corresponding voice coil, so that the cam mechanism is able to move under the control of a voice coil motor when input/output operations are performed and is able to move the actuator arm assembly during translation operations.

First claim

What is claimed is:

1. An actuator system for a reduced-head hard disk drive (HDD), the system comprising:
a ball screw cam assembly comprising:
a hollow screw comprising a particular number of starts encircling the screw,
a ball bearing assembly comprising the particular number of balls, wherein each ball rides in a corresponding start; and

an actuator arm coupled with the ball bearing assembly;
wherein the actuator arm translates along an axis of the screw upon rotation of the screw.

2. The actuator system of claim 1 , further comprising:
a stepper motor disposed within and coupled with the screw; and
wherein the stepper motor drives the rotation of the screw.

3. The actuator system of claim 2 , wherein the cam assembly and the disposed stepper motor are positioned in a pivot cartridge of the HDD.

4. The actuator system of claim 2 , wherein the stepper motor comprises a multi-phase claw-pole stepper motor.

5. A hard disk drive comprising the actuator system of claim 2 .

6. The actuator system of claim 1 , further comprising:
a voice coil configured to rotate the actuator arm, with which a read-write head slider is coupled, to move the head slider to access portions of a plurality of disk media;
a coil support structure to which the voice coil is fixedly coupled; and
a cam locking mechanism configured to couple the cam assembly with the coil support structure and decouple the cam assembly from the coil support structure;
wherein the cam assembly and the actuator arm rotate with the coil support structure when coupled therewith via the cam locking mechanism.

7. The actuator system of claim 1 , further comprising:
a voice coil configured to rotate the actuator arm, with which a read-write head slider is coupled, to move the head slider to access portions of a plurality of disk media;
a coil support structure to which the voice coil is fixedly coupled; and
a cam locking mechanism configured to couple the cam assembly with the coil support structure and to decouple the cam assembly from the coil support structure;
wherein the cam assembly and actuator arm are decoupled from the coil support structure via the cam locking mechanism when the actuator arm translates upon rotation of the screw.

8. The actuator system of claim 1 , further comprising:
a cam locking mechanism configured to couple the actuator arm with a coil support structure, to which a voice coil is fixedly coupled, and to decouple the actuator arm from the coil support structure, the cam locking mechanism comprising:
a tab extending from the actuator arm and positioned within a vertical gap formed in the coil support structure,
a vertical slit in the coil support structure configured to intersect the gap in the coil support structure, and
a compression spring mechanism, housed in the slit of the coil support structure, which applies a compression force to inner and outer portions of the coil support structure on each side of the gap,
wherein the compression force is such that the tab is held within the gap such that the actuator arm is coupled with the coil support structure.

9. The actuator system of claim 8 , wherein the cam locking mechanism further comprises:
a rotatable lock arm coupled with the coil support structure, comprising the outer portion of the coil support structure; and
an outer diameter crash stop;
wherein, in response to the actuator arm and coil support structure being driven to rotate such that the lock arm comes into contact with the crash stop, the compression force is overcome and the lock arm rotates such that the gap is widened and the tab is free to translate vertically within the gap.

10. A hard disk drive comprising the actuator system of claim 8 .

11. The actuator system of claim 1 , wherein the particular number of starts and the particular number of balls of the cam assembly is three or greater, thereby forming a plane on which the balls ride perpendicular to the axis of the screw.

12. The actuator system of claim 1 , wherein the ball screw cam assembly further comprises: a retaining ring configured to hold the particular number of balls in equal spacing, in a respective start of the particular number of starts, about an outer periphery of the screw.

13. The actuator system of claim 12 , wherein the ball screw cam assembly further comprises a bearing race ring that forms a first portion of an outer split-race with a surface of the actuator arm that forms a second portion of the outer split-race;
wherein the cam assembly is configured such that four points of contact are established with each of the balls, including contact with the first and the second portions of the outer split-race and contact with an upper portion and a lower portion of the respective start in which each ball rides.

14. A hard disk drive comprising the actuator system of claim 13 .

15. The actuator system of claim 13 , wherein the ball screw cam assembly further comprises:
an O-ring positioned in contact with the first portion of the outer split-race such that the O-ring applies a compression force to the first portion of the outer split-race.

16. A hard disk drive comprising the actuator system of claim 1 .

17. A cam assembly comprising:
a threaded screw comprising a particular number of starts encircling the screw,
a ball bearing assembly comprising the particular number of balls, wherein each ball rides in a corresponding start; and
a translating part coupled with the ball bearing assembly;
wherein the translating part translates along an axis of the screw upon rotation of the screw.

18. The cam assembly of claim 17 , wherein the particular number of starts and the particular number of balls is three or greater, thereby forming a plane on which the balls ride perpendicular to the axis of the screw.

19. The cam assembly of claim 17 , further comprising:
a retaining ring configured to hold the particular number of balls in equal spacing, in a respective start of the particular number of starts, about an outer periphery of the screw.

20. The cam assembly of claim 17 , further comprising:
a bearing race ring that forms a first portion of an outer split-race with a surface of the translating part that forms a second portion of the outer split-race;
wherein the cam assembly is configured such that four points of contact are established with each of the balls, including contact with the first and the second portions of the outer split-race and contact with an upper portion and a lower portion of the respective start in which each ball rides.

21. The cam assembly of claim 20 , further comprising:
an elastomeric O-ring positioned in contact with the first portion of the outer split-race such that the O-ring applies a compression force to the first portion of the outer split-race.

22. A reduced-head hard disk drive (HDD), comprising:
recording means for storing digital information;
reading/writing means for reading from and writing to the recording means;
means for moving the reading/writing means to access portions of the recording means;
means for translating the reading/writing means from one recording means to another recording means; and
means for locking the means for translating while the means for moving is operating and unlocking the means for translating while the means for moving is not operating.

23. An actuator system for a reduced-head hard disk drive (HDD), the system comprising:
a ball screw cam assembly comprising:
a hollo

Assignees

• Western Digital Tech Inc

Inventors

• Myers David
• Nguyen Diep

Classifications

• G11B5/4813

  Mounting or aligning of arm assemblies, e.g. actuator arm supported by bearings, multiple arm assemblies, arm stacks or multiple heads on single arm (G11B5/484 takes precedence) · CPC title

• G11B5/5569

  details of specially adapted mobile parts, e.g. electromechanical control devices (motors in general H02K) · CPC title

• H02K1/145

  having an annular coil, e.g. of the claw-pole type · CPC title

• H02K37/12

  with stationary armatures and rotating magnets · CPC title

• G11B5/55 Primary

  Track change, selection or acquisition by displacement of the head · CPC title