GB2358730A

GB2358730A - Actuator arm of varying thickness

Info

Publication number: GB2358730A
Application number: GB0028173A
Authority: GB
Inventors: Hae Sung Kwon; Shiao-Hua Chen; Ja Choon Koo
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 1999-11-17
Filing date: 2000-11-17
Publication date: 2001-08-01
Anticipated expiration: 2020-11-17
Also published as: GB2358730B; KR20010051673A; KR100385327B1; GB0028173D0

Abstract

A hard disk drive actuator arm 18 which has a finger 22 that extends from a centre portion 24 of the arm 18. The finger 22 has one or more steps 40, 42. The location and depth of the step(s) 40, 42 can be selected to obtain a desired natural resonant frequency of the actuator arm 18. The step(s) 40, 42 also reduces the mass of the arm 18. The lower mass may decrease the data access time and the power consumption of the hard disk drive.

Description

2358730 Stepped Actuator Arm of a Hard Disk Drive for High Shock Perf

ormance The present invention relates to an actuator arm of a hard 5 disk drive.

Hard disk drives include a plurality of transducers that are magnetically coupled to a number of rotating magnetic disks. The transducers write and read information by magnetizing and sensing the magnetic field of the disks. The transducers are typically integrated into heads that are mounted to suspension arms. The suspension arms are attached to an actuator arm. The disks are rotated by a spindle motor that is mounted to a base plate of the disk drive.

Information is typically stored within data sectors located in annular tracks of the disks. The actuator arm is attached to a voice coil motor that can be energized to move the heads to different tracks of the disks. It is generally desirable to provide a system that can rapidly move the transducers from track to track to minimize the access time of the disk drive.

Each head has an air bearing surface that cooperates with an air flow generated by the rotating disks to create an air bearing between the transducers and the disk surface. The air bearing prevents mechanical wear between the disk and the head. It is desirable to minimize the air bearing gap to optimize the magnetic coupling between the transducer and the disk surface.

2 Hard disk drives are sometimes subjected to a shock load. For example, the disk drive may be assembled into a portable computer that is dropped by the user. The shock load may propagate through the disk drive and cause the head to "'slap" the disk. The slapping action may damage the disk and/or head.

The disk drive may also be subjected to a vibration load. For example, rotation of the disks by the spindle motor may induce a vibration that is transferred into the suspension arm and cause relative movement between the head and the disk. This movement may affect the performance of the disk drive.

According to a first aspect of the present invention, there is provided an actuator arm for a hard disk drive, comprising: a centre portion; and a finger that extends from said centre portion, said finger having one or more step.

The actuator may further comprise a voice coil portion that extends from said centre portion.

Said centre portion may have a bearing opening.

Said finger may have a swage opening.

Preferably, there is a step at an intersection of said finger and said centre portion.

According to a second aspect of the invention, there is provided a hard disk drive, comprising: a base plate; a spindle motor mounted to said base plate; a disk rotated 3 by said spindle motor; an actuator arm mounted to said base plate, said actuator arm having a finger that extends from a centre portion, said finger having one or more step; a suspension arm attached to said finger; a head mechanically coupled to said suspension arm and magnetically coupled to said disk; and a voice coil motor coupled to said actuator arm.

Said voice coil motor may include a voice coil that is attached to a voice coil portion of said actuator arm.

Said actuator arm may be mounted to said base plate with a bearing assembly.

Preferably, said suspension arm is attached to said actuator arm through a swage opening in said finger.

Preferably, there is a step at an intersection of said finger and said centre portion of said actuator arm.

Preferably, a desired natural resonant frequency for the actuator arm is determined and the or each step is selected to obtain the desired natural resonant frequency.

According to a third aspect, there is provided a method for designing an actuator arm for a hard disk drive, comprising: determining a desired natural resonant frequency for an actuator arm; and, creating an actuator arm which has a finger that extends from a centre portion wherein the finger has a step to obtain the desired natural resonant frequency.

4 Preferably, there is created a step at an intersection of the finger and the centre portion.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:

Figure 1 is a top view of an embodiment of a hard disk drive of the present invention; and Figure 2 is a side view of an actuator arm of the hard disk drive.

In general the present invention includes designing one or more steps into a finger of a hard disk drive actuator arm. The location and depth of the or each step can be selected to obtain a desired natural resonant frequency for the actuator arm. The or each step also reduces the mass of the arm. The lower mass may decrease the data access time and the power consumption of the hard disk drive.

Referring to the drawings more particularly by reference numbers, f igures 1 and 2 show an embodiment of a hard disk drive 10 of the present invention. The disk drive 10 includes one or more disks 12 that are clamped to a spindle motor 14. The spindle motor 14 rotates the disks 12. The spindle motor 14 is mounted to a base plate 16 of the drive 10.

The disk drive 10 also has an actuator arm 18 that is pivotally mounted to the base plate 16 by a bearing assembly 20. The actuator arm 18 includes a plurality of fingers 22 that extend from a centre portion 24. The centre portion 24 has an opening 26 that houses the bearing assembly 20.

A plurality of suspension arms 28 are attached to the f inger 22. Each suspension arm 28 can be swaged to a corresponding finger 22 through a swage opening 29 in the f inger 22. There are typically two suspension arms 28 attached to each f inger 22.

A head 30 is gimbal mounted to each suspension arm 28. Each head 30 has one or more transducers (not shown) that are magnetically coupled to an adjacent disk surface. For is example, each head 30 may have a transducer that magnetizes and writes information onto a disk 12, and a separate magneto-resistive transducer that senses the magnetic field and reads information from the disk 12.

The actuator arm 18 may have a voice coil portion 32 that supports a voice coil 34. The voice coil 34 is coupled to a magnet assembly 36. The coil 34 and magnet assembly 36 define a voice coil motor 38 that can be energized to pivot the actuator arm 18 and move the heads 30 across the disks 12. The disks 12 and arm 18 are enclosed by a cover 39 that is attached to the base plate 16.

Each finger 22 has a step 40 located at the intersection of the f inger 22 and the centre portion 24. Each finger 22 also has one or more additional steps 42. The depth and/or location of the steps 40 and 42 can be designed so that the actuator arm 18 has a desired natural resonant frequency. For example, the steps 40 and 42 may be 6 designed so that the actuator arm 18 and suspension arms 28 have a natural resonant frequency that is outside the range of vibration frequencies normally encountered by a hard disk drive. Additionally, it is desirable to design the actuator arm 18 and suspension arms 28 to dampen shock loads normally encountered by a hard disk drive. The steps 80 and/or 82 can be designed to obtain a desired damping coefficient.

The steps 40 and 42 can be designed by first determining the desired natural resonant frequency and/or damping coefficient for the actuator arm 18. Given the desired design criteria the location and depth of the steps 40 and 42 can then be determined to create an actuator arm 18.

While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention need not be limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those ordinarily skilled in the art.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in thisspecification (including any accompanying claims, abstract and 7 drawings) and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s). The invention extend to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

8

Claims

1. An actuator arm for a hard disk drive, comprising:

a centre portion; and a finger that extends from said centre portion, said finger having one or more step.

2. The actuator of claim 1, further comprising a voice coil portion that extends from said centre portion.

3. The actuator of claim 1 or 2, wherein said centre portion has a bearing opening. is

4. The actuator of claim 1, 2 or 3, wherein said f inger has a swage opening.

5. The actuator of claim 1, 2, 3 or 4, wherein there is a 20 step at an intersection of said finger and said centre portion.

6. A hard disk drive, comprising:

a base plate; a spindle motor mounted to said base plate; a disk rotated by said spindle motor; 30 an actuator arm mounted to said base plate, said actuator arm having a finger that extends from a centre portion, said finger having one or more step; 9 a suspension arm attached to said f inger; a head mechanically coupled to said suspension arm and 5 magnetically coupled to said disk; and a voice coil motor coupled to said actuator arm.

7. The hard disk drive of claim 6 or 7, wherein said voice coil motor includes a voice coil that is attached to a voice coil portion of said actuator arm.

8. The hard disk drive of claim 6, wherein said actuator arm is mounted to said base plate with a bearing assembly.

is

9. The hard disk drive of claim 6, 7 or 8, wherein said suspension arm is attached to said actuator arm through a swage opening in said finger.

10. The hard disk drive of claim 6, 7, 8 or 9, wherein there is a step at an intersection of said f inger and said centre portion of said actuator arm.

11. The actuator arm of any of claims 1 to 5 or the hard disk drive of any of claims 6 to 10, wherein a desired natural resonant frequency for the actuator arm is determined and the or each step is selected to obtain the desired natural resonant frequency.

12. A method for designing an actuator arm f or a hard disk drive, comprising:

determining a desired natural resonant frequency for an actuator arm; and, creating an actuator arm which has a finger that extends from a centre portion wherein the finger has a step selected to obtain the desired natural resonant frequency.

13. The method of claim 11, wherein there is created a step at an intersection of the finger and the centre portion.

14. An actuator arm substantially as herein described with reference to the accompanying drawings.

is

15. A hard disk drive substantially as herein described with reference to the accompanying drawings.

16. A method for designing an actuator arm substantially as herein described with reference to the accompanying drawings.