US5625511A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stepped spindle motor shaft to reduce disk drive acoustic noise
Assignee: HGST Netherlands BV
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Filing: 1995-01-11
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Granted: 1997-04-29
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Expires: 2015-01-11
Abstract
Abstract A spindle motor shaft having variable geometrical features for adjusting the torsion mode frequency of the shaft/stator assembly. The variable geometric features allow the torsion mode frequency to be tuned away from the driving force frequency of the motor. Variable geometrical features for the shaft may include circumferential grooves, radial slots cut through the shaft, or transverse holes disposed along the axis of the shaft. The radial slots have a longitudinal axis that is parallel to the axis of the shaft. Where circumferential grooves are used, the circumferential grooves may be designed to form a locator region along the shaft axis to promote axial alignment of the shaft and stator. Thermal track-misregistration (TMR) or screw torque problems are not introduced in the process of reducing or eliminating the acoustic problem thereby establishing a torsion mode frequency which is not subject to change due to temperature or time. Further, the removal of material from the shaft reduces the torsional stiffness of the shaft and lowers the torsion mode frequency of the shaft. Finally, the use of circumferential grooves prevents the wicking of excess epoxy up the shaft by the movement of the stator during the assembly/manufacturing process, which may lead to an undesirable increase in the stiffness.
Inventors
- 👤 Peter E. Brooks
- 👤 Gregory M. Frees
- 👤 Daniel R. Stacer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:27
CPC Classifications
F; F16; F16C; F16C3/00; F16C3/02; F16F; F16F15/00; F16F15/10; G; G11; G11B; G11B19/00; G11B19/20; G11B19/2009; H; H02; H02K; H02K7/00; H02K7/14; H02K7/16; F16C2370/00; F16C2370/12
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
81 words
A spindle motor shaft for a disk drive system having a longitudinal axis, the shaft being coupled to a stator for generating motor drive forces at a driving force frequency, the shaft and stator further having a torsion mode frequency, the spindle motor shaft comprising at least one torsion mode frequency aperture formed in the spindle motor shaft, the torsion mode frequency aperture reducing the stiffness of the shaft and moving the torsion mode frequency away from the driving force frequency.
Claim 2
Dependent Claim
81 words
A spindle motor shaft for a disk drive system having a longitudinal axis, the shaft being coupled to a stator for generating motor drive forces at a driving force frequency, the shaft and stator further having a torsion mode frequency, the spindle motor shaft comprising at least one torsion mode frequency aperture formed in the spindle motor shaft, the torsion mode frequency aperture reducing the stiffness of the shaft and moving the torsion mode frequency away from the driving force frequency.
Claim 3
Dependent Claim
22 words
The spindle motor shaft of claim 1 wherein the at least one torsion mode frequency aperture comprises at least one circumferential groove.
Claim 4
Dependent Claim
43 words
The spindle motor shaft of claim 2 wherein the circumferential groove comprises a first predetermined width, the first predetermined width of the groove being selected to form a locator region along the shaft axis to promote axial alignment of the shaft and stator.
Claim 5
Dependent Claim
59 words
The spindle motor shaft of claim 3 wherein the locator region comprises an ungrooved portion of the shaft, the groove of a first predetermined width and the ungrooved portion of the shaft being overlapped by a short axial length of the stator, the ungrooved portion of the shaft preventing the stator from becoming cocked with respect to the shaft.
Claim 6
Dependent Claim
76 words
The spindle motor shaft of claim 2 wherein the shaft further comprises a knurled region generally centrally disposed along the axis of the shaft, the knurled region being coated with epoxy and the stator being moved onto and press-fitted over the knurled region, the circumferential groove preventing epoxy being expunged from between the shaft and the stator during the press-fitting from being wicked up the shaft by the movement of the stator onto the knurled region.
Claim 7
Dependent Claim
23 words
The spindle motor shaft of claim 1 wherein the at least one torsion mode frequency aperture comprises radial slots cut in the shaft.
Claim 8
Dependent Claim
28 words
The spindle motor shaft of claim 6 wherein the radial slots comprise longitudinal axes, the axes of the radial slots being parallel to the axis of the shaft.
Claim 9
Dependent Claim
26 words
The spindle motor shaft of claim 1 wherein the at least one torsion mode frequency aperture comprises transverse holes disposed along the axis of the shaft.
Claim 10
Dependent Claim
32 words
The spindle motor shaft of claim 1 wherein the shaft further comprises a knurled region disposed generally centrally along the axis of the shaft, the stator being press-fitted over the knurled region.
Claim 11
Dependent Claim
29 words
The spindle motor shaft of claim 9 wherein the shaft further comprises undercuts above and below the knurled region to capture metallic shavings created during the stator press-fitting process.
Claim 12
Dependent Claim
22 words
The disk drive system of claim 10 wherein the at least one torsion mode frequency aperture comprises at least one circumferential groove.
Claim 13
Dependent Claim
43 words
The disk drive system of claim 11 wherein the circumferential groove comprises a first predetermined width, the first predetermined width of the groove being selected to form a locator region along the shaft axis to promote axial alignment of the shaft and stator.
Claim 14
Dependent Claim
59 words
The disk drive system of claim 12 wherein the locator region comprises an ungrooved portion of the shaft, the groove of a first predetermined width and the ungrooved portion of the shaft being overlapped by a short axial length of the stator, the ungrooved portion of the shaft preventing the stator from becoming cocked with respect to the shaft.
Claim 15
Dependent Claim
76 words
The disk drive system of claim 11 wherein the shaft further comprises a knurled region generally centrally disposed along the axis of the shaft, the knurled region being coated with epoxy and the stator being moved onto and press-fitted over the knurled region, the circumferential groove preventing epoxy being expunged from between the shaft and the stator during the press-fitting from being wicked up the shaft by the movement of the stator onto the knurled region.
Claim 16
Dependent Claim
156 words
A disk drive system, comprising: a device enclosure; at least one storage disk; a motor, coupled to the device enclosure and the storage disk, for rotating the storage disk; a positional head assembly, coupled to the storage disk, for transferring data to and from the storage disk; and a disk controller, connected to the motor and the positional head assembly, for controlling the position of the storage disk and the head assembly; and wherein the motor comprises a spindle motor shaft having a longitudinal axis, the shaft being coupled to a stator for generating motor drive forces at a driving force frequency, the shaft and stator further having a torsion mode frequency, the spindle motor shaft comprising at least one torsion mode frequency aperture formed in the spindle motor shaft, the at least one torsion mode frequency aperture reducing the stiffness of the shaft and moving the torsion mode frequency away from the driving force frequency.
Claim 17
Dependent Claim
156 words
A disk drive system, comprising: a device enclosure; at least one storage disk; a motor, coupled to the device enclosure and the storage disk, for rotating the storage disk; a positional head assembly, coupled to the storage disk, for transferring data to and from the storage disk; and a disk controller, connected to the motor and the positional head assembly, for controlling the position of the storage disk and the head assembly; and wherein the motor comprises a spindle motor shaft having a longitudinal axis, the shaft being coupled to a stator for generating motor drive forces at a driving force frequency, the shaft and stator further having a torsion mode frequency, the spindle motor shaft comprising at least one torsion mode frequency aperture formed in the spindle motor shaft, the at least one torsion mode frequency aperture reducing the stiffness of the shaft and moving the torsion mode frequency away from the driving force frequency.
Claim 18
Dependent Claim
23 words
The disk drive system of claim 15 wherein the at least one torsion mode frequency aperture comprises radial slots cut in the shaft.
Claim 19
Dependent Claim
28 words
The disk drive system of claim 16 wherein the radial slots comprise longitudinal axes, the axes of the radial slots being parallel to the axis of the shaft.
Claim 20
Dependent Claim
26 words
The disk drive system of claim 15 wherein the at least one torsion mode frequency aperture comprises transverse holes disposed along the axis of the shaft.
Claim 21
Dependent Claim
32 words
The disk drive system of claim 15 wherein the shaft further comprises a knurled region disposed generally centrally along the axis of the shaft, the stator being press-fitted over the knurled region.
Claim 22
Dependent Claim
29 words
The disk drive system of claim 19 wherein the shaft further comprises undercuts above and below the knurled region to capture metallic shavings created during the stator press-fitting process.
Claim 23
Independent Claim
93 words
A method of making a spindle motor shaft for a disk drive having a longitudinal axis, the shaft being coupled to a stator for generating motor drive forces at a driving force frequency, the shaft and stator further having a torsion mode frequency, the method comprising: creating a cylindrical shaft of a predetermined length; forming at least one torsion mode frequency aperture in the spindle motor shaft, the at least one torsion mode frequency aperture reducing the stiffness of the shaft and moving the torsion mode frequency away from the driving force frequency.
Claim 24
Independent Claim
93 words
A method of making a spindle motor shaft for a disk drive having a longitudinal axis, the shaft being coupled to a stator for generating motor drive forces at a driving force frequency, the shaft and stator further having a torsion mode frequency, the method comprising: creating a cylindrical shaft of a predetermined length; forming at least one torsion mode frequency aperture in the spindle motor shaft, the at least one torsion mode frequency aperture reducing the stiffness of the shaft and moving the torsion mode frequency away from the driving force frequency.
Claim 25
Dependent Claim
27 words
The method of claim 21 wherein the step of forming at least one torsion mode frequency aperture on the shaft comprises forming at least one circumferential groove.
Claim 26
Dependent Claim
41 words
The method of claim 22 wherein the circumferential groove comprises a first predetermined width, the first predetermined width of the groove being selected to form a locator region along the shaft axis to promote axial alignment of the shaft and stator.
Claim 27
Dependent Claim
57 words
The method of claim 23 wherein the locator region comprises a ungrooved portion of the shaft, the groove of a first predetermined width and the ungrooved portion of the shaft being overlapped by a short axial length of the stator, the ungrooved portion of the shaft preventing the stator from becoming cocked with respect to the shaft.
Claim 28
Dependent Claim
50 words
The method of claim 22 further comprises the steps of forming a knurled region disposed generally centrally along the axis of the shaft, the stator being press-fitted over the knurled region, and forming undercuts above and below the knurled region to capture metallic shavings created during the stator press-fitting process.
Claim 29
Dependent Claim
31 words
The method of claim 21 wherein the step of forming the at least one torsion mode frequency aperture on the shaft comprises forming at least one radial slot in the shaft.
Claim 30
Dependent Claim
33 words
The method of claim 26 wherein the at least one radial slot comprises a longitudinal axis, the axis of the at least one radial slot being parallel to the axis of the shaft.
Claim 31
Dependent Claim
29 words
The method of claim 21 wherein the step of forming the at least one torsion mode frequency aperture comprises forming transverse holes disposed along the axis of the shaft.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-04-28 | 2000-10-28 | 2001-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-04-28 | 2004-10-28 | 2005-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-04-28 | 2008-10-28 | 2009-04-29 | $7700.00 | Window Closed / Lapsed |