US5224782A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrodynamic bearing
Assignee: Ebara Corp
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Filing: 1991-10-25
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Granted: 1993-07-06
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Expires: 2011-10-25
Abstract
Abstract A hydrodynamic bearing for a spindle motor used in an environment of high degree of cleanness. A sliding surface of the hydrodynamic bearing is formed of a ceramic material with a surface roughness Ra not larger than 0.3 microns, and this sliding surface is coated thinly with at least one lubricant selected from among perfluoropolyethers having a functional group reactive with the ceramic material, thereby providing on the sliding surface a uniform thin film with a thickness in the range of from 20 to 100 angstrom and having protecting and lubricating functions. The lubricant is selected from among hydroxyl group-containing perfluoropolyethers, carboxyl group-containing perfluoropolyethers, and ester group-containing. The lubricant contains an antistatic agent.
Inventors
- 👤 Sachihiko Miwa
- 👤 Manabu Toshimitsu
- 👤 Kazuyuki Kasahara
- 👤 Yoshikazu Suganuma
- 👤 Yumiko Noda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:21
CPC Classifications
F; F16; F16C; F16C33/00; F16C33/02; F16C33/04; F16C33/06; F16C33/10; F16C33/1025; F16C33/106; F16C33/107; F16C17/00; F16C17/10; F16C17/102; F16C17/107; F16C33/043; F16C33/1005; F16C33/101; F16C33/1015; Y; Y10; Y10S; Y10S384/00; Y10S384/90; Y10S384/907
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
73 words
A hydrodynamic bearing comprising a sliding surface which is formed of a ceramic material with a surface roughness Ra not larger than 0.3 microns and coated with at least one lubricant selected from among perfluoropolyethers having a functional group reactive with said ceramic material, thereby providing on said sliding surface a uniform thin film with a thickness in the range of from 20 Å to 100 Å and having protecting and lubricating functions.
Claim 2
Dependent Claim
73 words
A hydrodynamic bearing comprising a sliding surface which is formed of a ceramic material with a surface roughness Ra not larger than 0.3 microns and coated with at least one lubricant selected from among perfluoropolyethers having a functional group reactive with said ceramic material, thereby providing on said sliding surface a uniform thin film with a thickness in the range of from 20 Å to 100 Å and having protecting and lubricating functions.
Claim 3
Dependent Claim
14 words
A hydrodynamic bearing according to claim 1, wherein said lubricant contains an antistatic agent.
Claim 4
Dependent Claim
53 words
A hydrodynamic bearing according to claim 2, wherein said antistatic agent is at least one surface-active agent selected from among polyhydric alcohol esters of fatty acid having monoalkyl, dialkyl, glycerin, sorbitol, polyglycerin or polyoxyethylene as a lipophilic group, or a polyoxyethylene additive having alkylamine, alkylamide, fatty alcohol or alkylphenol as a lipophilic group.
Claim 5
Dependent Claim
24 words
A hydrodynamic bearing according to claim 1, wherein said lubricant is selected from among hydroxyl group-containing perfluoropolyethers, carboxyl group-containing perfluoropolyethers, and ester group-containing perfluoropolyethers.
Claim 6
Dependent Claim
63 words
A hydrodynamic bearing according to claim 1, wherein said lubricant is coated in such a manner that a bearing member is first degreased and dried thoroughly and then dipped in said lubricant dissolved in a solvent, or said lubricant is attached to said sliding surface by spin coating or spray coating, and then said coated lubricant is heated to form a thin film.
Claim 7
Dependent Claim
50 words
A hydrodynamic bearing according to claim 1, wherein said perfluoropolyether lubricants having a functional group are polymers which have a principal structural unit represented by the general formula --C X F 2X --O-- (X is an integer of 1 to 4) and an average molecular weight of 1,000 to 5,000.
References Cited (Backward Citations)
US5076716A
Cited
US5114886A
Cited
JPS6357914A
Cited
JPS6372743A
Cited
US4728201A
Cited
US5114245A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-07-05 | 1997-01-04 | 1997-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-05 | 2001-01-04 | 2001-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-05 | 2005-01-04 | 2005-07-06 | $7700.00 | Window Closed / Lapsed |