TREA

Wave stringer for controlling acoustic noise and shock vibration in a storage device

Follow

Information

  • Patent Grant
  • 6947252
  • Patent Number
    6,947,252
  • Date Filed
    Monday, May 7, 2001
    23 years ago
  • Date Issued
    Tuesday, September 20, 2005
    19 years ago
Information
Abstract
A hard disk drive that includes a wave stringer. The wave stringer can attenuate energy which propagates through a base plate of the disk drive. The wave stringer may be designed by initially analyzing propagation patterns of both acoustic and shock waves applied to the drive. The wave stringer is then designed, constructed and assembled to the disk drive to attenuate critical frequencies at weak points of the disk drive. The wave stringer may have a plurality of ribs designed to vary the mechanical impedance of the drive to attenuate the propagated energy.
Description
BACKGROUND OF THE INVENTION

1. Field of the Invention


The present invention relates to a wave stringer to attenuate energy that propagates through a hard disk drive.


2. Background Information


Hard disk drives contain a plurality of magnetic heads that are coupled to rotating disks. The heads write and read information by magnetizing and sensing the magnetic fields of the disk surfaces. There have been developed magnetic heads that have a write element for magnetizing the disks and a separate read element for sensing the magnetic fields of the disks. The read element is typically constructed from a magneto-resistive material. The magneto-resistive material has a resistance that varies with the magnetic fields of the disk. Heads with magneto-resistive read elements are commonly referred to as magneto-resistive (MR) heads.


Each head is attached to a suspension arm to create a subassembly commonly referred to as a head gimbal assembly (“HGA”). The HGA's are attached to an actuator arm which has a voice coil motor that can move the heads across the surfaces of the disks.


The disks are rotated by a spindle motor that is mounted to a base plate of the disk drive. The spindle motor may create a vibration that is transmitted through the base plate. The vibration may be in the audible frequency range so that the drive emits an undesirable noise. Additionally, the rotating disks may create a turbulent flow that generates a vibration in the housing which also creates an audible noise from the drive. It would be desirable to provide a structure that attenuates acoustic energy which propagates through the disk drive housing, and lowers the noise emitted from the drive.


Disk drives are sometimes subjected to external shock and/or vibration loads that may damage the internal components of the drive. It would also be desirable to provide a structure that attenuates shook/vibration waves which propagate through the housing of the drive.


BRIEF SUMMARY OF THE INVENTION

One embodiment of the present invention is a hard disk drive that includes a wave stringer which can attenuate energy within a base plate of the disk drive.





BRIEF DESCRIPTION OF THE DRAWINGS


FIG. 1 is a top view of an embodiment of a hard disk drive of the present invention;



FIG. 2 is a bottom view of the hard disk drive;



FIG. 3 is a cross-sectional view showing a wave stringer of the hard disk drive;



FIGS. 4
a-b are graphs showing acoustic noise emitted by a hard disk drive of the prior art and a disk drive of the present invention;



FIG. 5 is a schematic of an electrical system of the hard disk drive.





DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In general one embodiment of the present invention includes a hard disk drive that includes a wave stringer. The wave stringer can attenuate energy that propagates through a base plate of the disk drive. The wave stringer may be designed by initially analyzing propagation patterns of both acoustic and shock waves applied to the drive. The wave stringer is then designed, constructed and assembled to the disk drive to attenuate critical frequencies at weak points of the disk drive. The wave stringer may have a plurality of ribs designed to vary the mechanical impedance of the drive to attenuate the propagated energy.


Referring to the drawings more particularly by reference numbers, FIG. 1 shows an embodiment of a hard disk drive 10 of the present invention. The disk drive 10 may include one or more magnetic disks 12 that are rotated by a spindle motor 14. The spindle motor 14 may be mounted to a base plate 16. The disk drive 10 may further have a cover 18 that encloses the disks 12.


The disk drive 10 may include a plurality of heads 20 located adjacent to the disks 12. The heads 20 may have separate write and read elements (not shown) that magnetize and sense the magnetic fields of the disks 12.


Each head 20 may be gimbal mounted to a suspension arm 22 as part of a head gimbal assembly (HGA). The suspension arms 22 are attached to an actuator arm 24 that is pivotally mounted to the base plate 16 by a bearing assembly 26. A voice coil 28 is attached to the actuator arm 24. The voice coil 28 is coupled to a magnet assembly 30 to create a voice coil motor (VCM) 32. Providing a current to the voice coil 28 will create a torque that swings the actuator arm 24 and moves the heads 20 across the disks 12.


Each head 20 has an air bearing surface (not shown) that cooperates with an air flow created by the rotating disks 12 to generate an air bearing. The formation of the air bearing and the general operation of the head 20 is a function of a force exerted by the suspension arm 22. The force is commonly referred to as the gram load of the arm 22. A higher gram load corresponds to a stiffer suspension arm 22.


The hard disk drive 10 may include a printed circuit board assembly 34 that includes a plurality of integrated circuits 36 coupled to a printed circuit board 38. The printed circuit board 36 is coupled to the voice coil 28, heads 20 and spindle motor 14 by wires (not shown).



FIG. 2 shows a wave stringer 42 that is attached to the base plate 16 by a plurality of fasteners 44. The wave stringer 42 can vary the mechanical impedance of the base plate 16 and attenuate energy that propagates through the disk drive 10. For example, the wave stringer 42 can vary the disk drive structure to attenuate acoustic energy that propagates through the drive, or attenuate shock/vibration energy that propagates through the drive. The wave stringer 42 is located adjacent to the printed circuit board assembly 45.


As shown in FIG. 3, the wave stringer 42 may have a plurality of ribs 46 separated by channels 48. The ribs 46 and channels 48 may be designed to optimize the attenuation of energy in the disk drive 10. The width and location of the ribs 46 may be unsymmetric to reduce the harmonics in the drive.


The wave stringer 42 may be designed by initially determining and analyzing the sound intensity radiation pattern over the entire outside surface of the base plate 16 and cover 18. Additionally, analysis may be performed on the operational deflection of the base plate 16. The weak points of the base plate 16 can then be identified to determine where the wave stringer 42 should be attached to the drive and how the stringer 42 should be configured to attenuate the acoustic energy.


As part of the design process for the wave stringer 42 shock/vibration propagation patterns may be determined and analyzed in response to an external shock and/or vibration load. Further analysis may be performed to determine critical time and critical frequencies of the shock load propagating through the disk drive. The weak points of the base plate 16 can then be identified to determine where the wave stringer 42 should be attached to the drive 10 and how the stringer 42 should be configured to attenuate the shock/vibration energy. The analysis for both the acoustic and shock/vibration energy can be performed with finite element computer generated models that identify areas of maximum base plate deflection. The models can be modified to incorporate a wave stringer design and to determine the effects of the wave stringer. The wave stringer can be iteratively varied and analyzed to provide an optimum design.


The wave stringer 42 may be attached to the base plate 16 adjacent to the spindle motor 14. This placement of the wave stringer 42 will more effectively attenuate vibration energy generated by the motor 14.



FIGS. 4
a and 4b show an attenuation of acoustic energy for a hard disk drive of the prior art without a wave stringer 42 and a disk drive 10 of the present invention with a wave stringer 42. In general the wave stringer 42 reduces noise levels across the entire frequency spectrum. As shown by FIGS. 4a and 4b, some of the high frequency components have noise reductions up to 4 decibels.



FIG. 5 shows a schematic of an electrical system 50 that can control the disk drive 10. The electrical system 50 may be integrated into the printed circuit board assembly 36 shown in FIG. 1. The system 50 includes a controller 52 that is connected to an input/output (I/O) buffer 54, voice coil motor control circuit 56, spindle motor control circuit 58, read/write channel circuit 60, memory 62. The I/O buffer 54 provides an interface with an external source such as a personal computer. The voice coil control circuit 56 and spindle motor control circuit 58 contain drivers, etc. to control the voice coil motor and spindle motor, respectively.


The voice coil motor circuit 56 and spindle motor control circuit 58 operate in accordance with signals, commands, etc. from the controller 52. The controller 52 may be a processor that can perform software routines in accordance with instructions and data to operate the storage and retrieval of information from the disks 12.


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 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. For example, although the wave stringer 42 is shown and described as being attached to the base plate 16, the stringer 42, or an additional stringer 42, may be attached to the cover 18.

Claims
  • 1. A hard disk drive, comprising: a base plate that has an external cavity; a spindle motor coupled to said base plate; a disk coupled to said spindle motor; an actuator arm mounted to said base plate; a voice coil motor coupled to said actuator arm; a suspension arm coupled to said actuator arm, said suspension arm having a gram load; a head coupled to said suspension arm and said disk; a printed circuit board assembly located in said external cavity a wave stringer attached to said base plate within said external cavity and located adjacent to said printed circuit board in a non-overlapping manner, said wave stringer having a plurality of non-through hole openings that separate a plurality of ribs configured and located relative to said base plate to optimize attenuation of energy propagating through said base plate; and, a cover that is attached to said base plate and encloses said disk, said actuator arm, said voice coil motor, said suspension arm and said head.
  • 2. The hard disk drive of claim 1, wherein said wave stringer is adjacent to said spindle motor.
  • 3. The hard disk drive of claim 1, wherein said wave stringer attenuates vibration energy created by said spindle motor.
  • 4. The hard disk drive of claim 1, wherein said wave stringer attenuates shock energy from an external source.
  • 5. The hard disk drive of claim 1, wherein said wave stringer ribs are unsymmetrical.
  • 6. A hard disk drive, comprising: a base plate that has an external cavity; a spindle motor coupled to said base plate; a disk coupled to said spindle motor; an actuator arm mounted to said base plate; a voice coil motor coupled to said actuator arm; a suspension arm coupled to said actuator arm, said suspension arm having a gram load; a head coupled to said suspension arm and said disk; a printed circuit board assembly located in said external cavity; attenuation means for optimizing the attenuation of energy propagating through said base plate that is located within said external cavity of said base plate and adjacent to said printed circuit assembly in a non-overlapping manner; and, a cover that is attached to said base plate and encloses said disk, said actuator arm, said voice coil motor, said suspension arm and said head.
  • 7. The hard disk drive of claim 6, wherein said attenuation means includes a plurality of ribs.
  • 8. The hard disk drive of claim 6, wherein said attenuation means is adjacent to said spindle motor.
  • 9. The hard disk drive of claim 6, wherein said attenuation means attenuates vibration energy created by said spindle motor.
  • 10. The hard disk drive of claim 6, wherein said attenuation means attenuates shock energy from an external source.
  • 11. The hard disk drive of claim 7, wherein said ribs are unsymmetrical.
Parent Case Info

This application claims the benefit of U.S. Provisional Application No. 60/202,551, filed May 10, 2000.

US Referenced Citations (143)
Number Name Date Kind
3558831 Prescott et al. Jan 1971 A
4110802 Ho et al. Aug 1978 A
4280156 Villette Jul 1981 A
4491888 Brown et al. Jan 1985 A
4493554 Pryor et al. Jan 1985 A
4555739 Le Van et al. Nov 1985 A
4562500 Bygdnes Dec 1985 A
4630926 Tanaka et al. Dec 1986 A
4661873 Schulze Apr 1987 A
4673996 White Jun 1987 A
4703376 Edwards et al. Oct 1987 A
4731777 Yoshitoshi et al. Mar 1988 A
4739425 Dierkes et al. Apr 1988 A
4784012 Marra Nov 1988 A
4794588 Yoshitoshi et al. Dec 1988 A
4802042 Strom Jan 1989 A
4819105 Edwards Apr 1989 A
4839756 Chew et al. Jun 1989 A
4866553 Kubo et al. Sep 1989 A
4870519 White Sep 1989 A
4890172 Watt et al. Dec 1989 A
4949206 Phillips et al. Aug 1990 A
4958337 Yamanaka et al. Sep 1990 A
4982300 Forbord Jan 1991 A
5004207 Ishikawa et al. Apr 1991 A
5021905 Sleger Jun 1991 A
5029026 Stefansky et al. Jul 1991 A
5062017 Strom et al. Oct 1991 A
5097370 Hsia Mar 1992 A
5128822 Chapin et al. Jul 1992 A
5130870 Jabbari Jul 1992 A
5149048 Morehouse et al. Sep 1992 A
5159508 Grill et al. Oct 1992 A
5161900 Bougathou et al. Nov 1992 A
5167167 Tiernan, Jr. et al. Dec 1992 A
5175661 Mizuno et al. Dec 1992 A
5187621 Tacklind Feb 1993 A
5200868 Chapin et al. Apr 1993 A
5202803 Albrecht et al. Apr 1993 A
5214549 Baker et al. May 1993 A
5216582 Russell et al. Jun 1993 A
5235482 Schmitz Aug 1993 A
5241438 Matsushima Aug 1993 A
5243495 Read et al. Sep 1993 A
5247493 Kime et al. Sep 1993 A
5262911 Cain et al. Nov 1993 A
5262913 Stram et al. Nov 1993 A
5267109 Chapin et al. Nov 1993 A
5274519 Saito et al. Dec 1993 A
5287235 Cunningham et al. Feb 1994 A
5293282 Squires et al. Mar 1994 A
5309303 Hsia et al. May 1994 A
5319511 Lin Jun 1994 A
5333085 Prentice et al. Jul 1994 A
5343343 Chapin Aug 1994 A
5347414 Kano Sep 1994 A
5365389 Jabbari et al. Nov 1994 A
5369538 Moe et al. Nov 1994 A
5396386 Bolasna et al. Mar 1995 A
5396387 Murray Mar 1995 A
5402290 Daniel Mar 1995 A
5404256 White Apr 1995 A
5410402 Li et al. Apr 1995 A
5422776 Thorson et al. Jun 1995 A
5426562 Morehouse et al. Jun 1995 A
5442638 Awad et al. Aug 1995 A
5446611 Webber Aug 1995 A
5455728 Edwards et al. Oct 1995 A
5460017 Taylor Oct 1995 A
5463527 Hager et al. Oct 1995 A
5469311 Nishida et al. Nov 1995 A
5519552 Kohira et al. May 1996 A
5537272 Kazmierczak et al. Jul 1996 A
5546250 Diel Aug 1996 A
5555144 Wood et al. Sep 1996 A
5570249 Aoyagi et al. Oct 1996 A
5590095 Chaya Dec 1996 A
5610776 Oh Mar 1997 A
5612841 Johnson Mar 1997 A
5636090 Boigenzahn et al. Jun 1997 A
5663853 Park Sep 1997 A
5673158 Ichimura Sep 1997 A
5677813 Yoshida et al. Oct 1997 A
5703734 Berberich et al. Dec 1997 A
5754353 Behrens et al. May 1998 A
5757580 Andress et al. May 1998 A
5760998 Berberich et al. Jun 1998 A
5768249 Ro et al. Jun 1998 A
5781373 Larson et al. Jul 1998 A
5801899 Genheimer Sep 1998 A
5815349 Frater Sep 1998 A
5822139 Ayabe Oct 1998 A
5831795 Ma et al. Nov 1998 A
5844754 Stefansky et al. Dec 1998 A
5844911 Schadegg et al. Dec 1998 A
5875067 Morris et al. Feb 1999 A
5885005 Nakano et al. Mar 1999 A
5886851 Yamazaki et al. Mar 1999 A
5901017 Sano et al. May 1999 A
5926347 Kouhei et al. Jul 1999 A
5930079 Vera et al. Jul 1999 A
5930080 Frater et al. Jul 1999 A
5936927 Soga et al. Aug 1999 A
5969901 Eckberg et al. Oct 1999 A
5987733 Goss Nov 1999 A
6011670 Balsley, Jr. et al. Jan 2000 A
6034841 Albrecht et al. Mar 2000 A
6034941 Ro Mar 2000 A
6046883 Miller Apr 2000 A
6055134 Boutaghou Apr 2000 A
6084744 Genheimer et al. Jul 2000 A
6088192 Riener et al. Jul 2000 A
6088194 Imaino et al. Jul 2000 A
6088202 Kabasawa et al. Jul 2000 A
6091576 Eckerd et al. Jul 2000 A
6108163 Boutaghou Aug 2000 A
6115214 Allsup et al. Sep 2000 A
6122138 Khanna et al. Sep 2000 A
6154360 Kaczeus, Sr. et al. Nov 2000 A
6157522 Murphy et al. Dec 2000 A
6166901 Gamble et al. Dec 2000 A
6181525 Carlson Jan 2001 B1
6185075 Tsujino et al. Feb 2001 B1
6185807 Kazmierczak et al. Feb 2001 B1
6191915 Takagi et al. Feb 2001 B1
6198606 Boutaghou et al. Mar 2001 B1
6201668 Murphy Mar 2001 B1
6205005 Heath Mar 2001 B1
6212029 Fioravanti Apr 2001 B1
6226143 Stefanksy May 2001 B1
6226145 Genheimer et al. May 2001 B1
6226152 Tanaka et al. May 2001 B1
6226153 Tokuyama et al. May 2001 B1
6229668 Huynh et al. May 2001 B1
6233124 Budde et al. May 2001 B1
6236531 Allsup et al. May 2001 B1
6239943 Jennings et al. May 2001 B1
6266212 Coon Jul 2001 B1
6288866 Butler et al. Sep 2001 B1
6411463 Janik et al. Jun 2002 B1
6487039 Bernett Nov 2002 B1
6674608 Bernett Jan 2004 B1
6735043 Bernett et al. May 2004 B2
Foreign Referenced Citations (19)
Number Date Country
0 426 353 May 1991 EP
0 463 752 Jan 1992 EP
0 491 563 Jun 1992 EP
0 582 464 Feb 1994 EP
0 801 387 Oct 1997 EP
2518-791 Jun 1983 FR
2 050 670 Jan 1981 GB
2 100 052 Dec 1982 GB
2 326 755 Dec 1998 GB
632 344 55 Sep 1988 JP
01245479 Sep 1989 JP
3-83281 Apr 1991 JP
3-104079 May 1991 JP
06012635 Jan 1994 JP
09251769 Sep 1997 JP
9-293370 Nov 1997 JP
10-320964 Dec 1998 JP
WO 9310494 May 1993 WO
WO 9634390 Oct 1996 WO
Related Publications (1)
Number Date Country
20020008933 A1 Jan 2002 US
Provisional Applications (1)
Number Date Country
60202551 May 2000 US