Patent US4907897A successfully refreshed from Google Patents.
US4907897A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bearing device
Assignee: Nidec Instruments Corp
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Filing: 1987-10-22
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Granted: 1990-03-13
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Expires: 2007-10-22
Abstract
Abstract An improved bearing device for use in a spindle motor for driving computer hard disks is disclosed. The device includes a shaft, bearings supporting the shaft, and a bearing holder for holding the bearings. The bearing holder is made of a magnetic material. The shaft, the bearings, and the bearing holder are made of materials having substantially the same thermal expansion coefficient.
Inventors
- 👤 Yozo Shirotori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:37
CPC Classifications
H; H02; H02K; H02K5/00; H02K5/04; H02K5/12; H02K5/124; F; F16; F16C; F16C19/00; F16C19/52; F16C19/525; F16C25/00; F16C25/06; F16C25/08; G; G11; G11B; G11B19/00; G11B19/20; G11B33/00; G11B33/14; G11B33/1406; G11B33/1433; H02K5/16; H02K5/173; H02K5/1735; F16C2202/00; F16C2202/20; F16C2202/22; F16C2370/00; F16C2370/12; Y; Y10; Y10S; Y10S384/00; Y10S384/90; Y10S384/912
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
116 words
A bearing device comprising: a housing; a bearing holder having substantially the form of a cylindrical pipe, a lower end of said bearing holder being fitted in a central hole formed in said housing, said bearing holder being made of a magnetic material; a shaft; first and secod ball bearings fitted in said hearing holder and supporting said shaft; two yokes and a magnet held between said two yokes and fitted in an upper portion of said bearing holder; and a seal mechanism impregnated with magnetic fluid fitted between said shaft and inner peripheries of said yokes; said shaft, said bearings, and said bearing holder being made of materials which have substantially equal thermal expansion coefficients.
Claim 2
Dependent Claim
116 words
A bearing device comprising: a housing; a bearing holder having substantially the form of a cylindrical pipe, a lower end of said bearing holder being fitted in a central hole formed in said housing, said bearing holder being made of a magnetic material; a shaft; first and secod ball bearings fitted in said hearing holder and supporting said shaft; two yokes and a magnet held between said two yokes and fitted in an upper portion of said bearing holder; and a seal mechanism impregnated with magnetic fluid fitted between said shaft and inner peripheries of said yokes; said shaft, said bearings, and said bearing holder being made of materials which have substantially equal thermal expansion coefficients.
Claim 3
Dependent Claim
33 words
The bearing device of claim 1, wherein said ball bearings have no inner races, and the balls of said ball bearings ride in respective grooves formed in an outer surface of said shaft.
Claim 4
Dependent Claim
80 words
The bearing device of claim 1, wherein one of said bearings is fitted against a step formed in an upper portion of an inner wall of said bearing holder, is shrink-fitted into said upper portion of said bearing holder, and is held therein with an adhesive, and the other of said bearing is fitted in a lower portion of said inner wall of said bearing holder and held therein with an adhesive injected through holes formed in said inner wall.
Claim 5
Dependent Claim
15 words
The bearing device of claim 3, further comprising a coil spring fitted between said bearings.
Claim 6
Dependent Claim
21 words
The bearing device of claim 4, further comprising collars disposed between respective ends of said coil spring and said bearing holders.
Claim 7
Dependent Claim
42 words
The bearing device of claim 3, wherein said ball bearings have inner and outer races, and further comprising a coil spring fitted between the lower one of said bearings and a surface of said step opposite the upper one of said bearings.
Claim 8
Dependent Claim
27 words
The bearing device of claim 1, wherein said shaft and said bearing holder are made of martensite stainless steel and said bearings are made of bearing steel.
Claim 9
Dependent Claim
23 words
The bearing device as claimed in claim 1, wherein said shaft, said bearings and said bearing holder are made of martensite stainless steel.
Claim 10
Dependent Claim
22 words
The bearing device as claimed in claim 1, wherein said shaft, said bearing and said bearing holder are made of bearing steel.
Claim 11
Dependent Claim
64 words
A bearing device comprising: a shaft; bearings supporting such shaft; a bearing holder adapted to hold said bearings, wherein said shaft, said bearings and said bearing holder are made of materials which have substantially equal thermal expansion coefficients; a hub rotated together with said shaft, said hub supporting magnetic disks; rotor magnets rotated together with said shaft; and a stator confronting said rotor magnets.
Claim 12
Dependent Claim
64 words
A bearing device comprising: a shaft; bearings supporting such shaft; a bearing holder adapted to hold said bearings, wherein said shaft, said bearings and said bearing holder are made of materials which have substantially equal thermal expansion coefficients; a hub rotated together with said shaft, said hub supporting magnetic disks; rotor magnets rotated together with said shaft; and a stator confronting said rotor magnets.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-03-12 | 1993-09-11 | 1994-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-12 | 1997-09-11 | 1998-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-12 | 2001-09-11 | 2002-03-13 | $7700.00 | Window Closed / Lapsed |