Patent US4653625A successfully refreshed from Google Patents.
US4653625A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluid friction clutch
Assignee: ZF Friedrichshafen AG
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Filing: 1986-05-19
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Granted: 1987-03-31
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Expires: 2006-05-19
Abstract
Abstract The temperature-controlled fluid friction clutch, suitable especially for a cooling fan, comprises a rotor which is arranged in a housing, rotatably in relation to the housing, forming at least one shear gap for the viscous fluid transmitting the torque. A scraper conveys the viscous fluid according to the dynamic pressure principle out of a working chamber containing the rotor into a reservoir chamber. The scraper is connected with the housing and lied radially opposite to the external circumference of the rotor, forming a scraper gap. The housing consists of a material the coefficient of thermal expansion of which is greater than that of the material of the rotor. In this way the scraper gap is enlarged with rising temperature, whereby the pump power of the scraper is reduced with rising temperature. The clutch unites good cold-start behavior with low temperature-actuation hysteresis in the operationally hot condition. '
Inventors
- 👤 Dieter Neugebauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:27
CPC Classifications
F; F16; F16D; F16D35/00; F16D35/02; F16D35/021; F16D35/022
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
209 words
A fluid friction clutch comprising a rotor rotatable about a rotation axis, a housing coaxially rotatable in relation to the rotor and containing a reservoir chamber for viscous fluid and a working chamber, wherein said rotor is arranged in the working chamber and together with the housing forms at least one shear gap for the torque transmission, and a control device for the temperature-dependent controlling of a circulation of the viscous fluid between the reservoir chamber and the working chamber, wherein said control device comprises a temperature-dependent valve and a pump device effective on relative rotation of the rotor and the housing, in the region of the external circumference of the rotor, wherein said pump device comprises mutually radially opposite annular surfaces radially defining an annular pump gap, on the rotor and the housing and at least one scraper element which protrudes radially from the annular surface of the housing towards the annular surface of the rotor and with the annular surface of the rotor defines a radial scraper gap, and wherein the part forming said radially outer annular surface and carrying the scraper element consists of a material which has a greater coefficient of thermal expansion than the material of the part forming said radially inner annular surface.
Claim 2
Dependent Claim
209 words
A fluid friction clutch comprising a rotor rotatable about a rotation axis, a housing coaxially rotatable in relation to the rotor and containing a reservoir chamber for viscous fluid and a working chamber, wherein said rotor is arranged in the working chamber and together with the housing forms at least one shear gap for the torque transmission, and a control device for the temperature-dependent controlling of a circulation of the viscous fluid between the reservoir chamber and the working chamber, wherein said control device comprises a temperature-dependent valve and a pump device effective on relative rotation of the rotor and the housing, in the region of the external circumference of the rotor, wherein said pump device comprises mutually radially opposite annular surfaces radially defining an annular pump gap, on the rotor and the housing and at least one scraper element which protrudes radially from the annular surface of the housing towards the annular surface of the rotor and with the annular surface of the rotor defines a radial scraper gap, and wherein the part forming said radially outer annular surface and carrying the scraper element consists of a material which has a greater coefficient of thermal expansion than the material of the part forming said radially inner annular surface.
Claim 3
Dependent Claim
102 words
A fluid friction clutch according to claim 1, wherein the rotor is formed as a disc held on an input shaft, the external circumference of said disc forming the radially inner annular surface, wherein the housing has at least one face wall mounted rotatably on the input shaft and the scraper element is connected radially outside the external circumference of the disc with said face wall, and wherein at least said face wall of the housing mounted on the input shaft consists of a material the coefficient of thermal expansion of which is greater than that of the material of the disc.
Claim 4
Dependent Claim
19 words
A fluid friction clutch according to claim 1, wherein the scraper element is integrally connected with the face wall.
References Cited (Backward Citations)
US3419122A
Cited
US3463282A
Cited
US3858697A
Cited
US4086989A
Cited
US4116318A
Cited
US4271946A
Cited
US4441599A
Cited
US4485902A
Cited
US4446952A
Cited
US4403684A
Cited
US4437554A
Cited
US4564094A
Cited
US4564093A
Cited
US4592456A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-03-30 | 1990-09-29 | 1991-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-30 | 1994-09-29 | 1995-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-30 | 1998-09-29 | 1999-03-31 | $7700.00 | Window Closed / Lapsed |