US4893387A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Roller elements for roller bearing
Assignee: NTN Corp
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Filing: 1989-02-27
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Granted: 1990-01-16
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Expires: 2009-02-27
Abstract
Abstract A roller element for use in a roller bearing having a surface formed with minute recesses at random so that the ratio RMS(L)/RMS(C) will be not more than 0.8 wherein RMS(L) is the roughness mean square value in the longitudinal direction and RMS(C) is the roughness mean square value in the circumferential direction and so that the SK value is not more than -0.2 in both the longitudinal and circumferential directions.
Inventors
- 👤 Yoshinobu Akamatsu
- 👤 Morikatu Kotani
- 👤 Toshihide Goto
- 👤 Kenji Hibi
- 👤 Toshihiko Matsushima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:31
CPC Classifications
F; F16; F16C; F16C35/00; F16C33/00; F16C33/30; F16C33/34; F16C33/66; F16C33/6637; F16C33/664; F16C33/6651; F16C2240/00; F16C2240/40; F16C2240/54; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49636; Y10T29/49643; Y10T29/49679; Y10T29/49693
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
119 words
A roller element for use in a roller bearing, said roller element having a surface extending in longitudinal and circumferential directions and formed with a multiplicity of minute recesses arranged in random directions on said surface so that the ratio RMS(L)/RMS(C) is not more than 0.8 wherein RMS(L) is the surface roughness mean square value in the longitudinal direction of said surface and RMS(C) is the surface roughness mean square value in the circumferential direction of the surface and so that the SK value is not more than -2.0 in both the longitudinal and circumferential directions of said surface wherein the SK value represents skewness that indicates a distribution curve of surface roughness of said longitudinal and circumferential surface.
Claim 2
Dependent Claim
119 words
A roller element for use in a roller bearing, said roller element having a surface extending in longitudinal and circumferential directions and formed with a multiplicity of minute recesses arranged in random directions on said surface so that the ratio RMS(L)/RMS(C) is not more than 0.8 wherein RMS(L) is the surface roughness mean square value in the longitudinal direction of said surface and RMS(C) is the surface roughness mean square value in the circumferential direction of the surface and so that the SK value is not more than -2.0 in both the longitudinal and circumferential directions of said surface wherein the SK value represents skewness that indicates a distribution curve of surface roughness of said longitudinal and circumferential surface.
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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) | 1993-01-15 | 1993-07-17 | 1994-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-15 | 1997-07-17 | 1998-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-15 | 2001-07-17 | 2002-01-16 | $7700.00 | Window Closed / Lapsed |