Patent US4736828A successfully refreshed from Google Patents.
US4736828A
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Clutch discs for a fluid friction clutch and process for making same
Assignee: Volkswagen AG
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Filing: 1987-03-11
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Granted: 1988-04-12
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Expires: 2007-03-11
Abstract
Abstract Lamellar clutch discs consisting of sheet steel and arranged in an enclosed housing filled with a viscous liquid medium for a fluid friction clutch are described. To achieve a torque transmission behavior of the clutch that will remain constant over long periods of time, the surfaces of the discs are to exhibit a roughness with an arithmetic mean rugosity R a in the range between 0.2 and 2 microns and a profile depth P t in the range between 2 and 15 microns. Furthermore, the distance between neighboring elevations of the rugosity profile is to lie in the range between 50 and 750 microns, and the surfaces are to have a wear-reducing nickel-phosphorus coating.
Inventors
- 👤 Eberhard Diessner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 15:03
CPC Classifications
F; F16; F16D; F16D35/00; F16D35/005; B; B23; B23P; B23P15/00; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49462; Y10T29/49467; Y10T29/4948; Y10T29/4998; Y10T29/49982; Y10T29/49986; Y10T29/49988; Y10T29/49991; Y10T29/49995; Y10T29/49996
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
43 words
Lamellar clutch discs comprised of sheet steel and provided with surfaces having a roughness with an arithmetic mean rugosity R a in the range between 0.2 and 2.0, microns and a profile depth P t in the range between 2.0 and 15 microns.
Claim 2
Dependent Claim
43 words
Lamellar clutch discs comprised of sheet steel and provided with surfaces having a roughness with an arithmetic mean rugosity R a in the range between 0.2 and 2.0, microns and a profile depth P t in the range between 2.0 and 15 microns.
Claim 3
Dependent Claim
23 words
Clutch discs as defined in claim 1, wherein neighboring elevations of the rugosity profile lie in the range between 50 and 750 microns.
Claim 4
Dependent Claim
20 words
Clutch discs as defined in claim 1 or 2, wherein the disc surfaces are provided with a wear-reducing nickel-phosphorus coating.
References Cited (Backward Citations)
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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) | 1991-04-12 | 1991-10-12 | 1992-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-12 | 1995-10-12 | 1996-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-12 | 1999-10-12 | 2000-04-12 | $7700.00 | Window Closed / Lapsed |