US4858516A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brake cylinder-piston slave unit seal having radial roll-back protrusion for piston spring back retract
Assignee: Continental Teves AG and Co OHG
•
Filing: 1984-06-22
•
Granted: 1989-08-22
•
Expires: 2004-06-22
Abstract
Abstract In a piston-cylinder assembly for hydraulic brake systems of automotive vehicles, the piston is at least partially composed of ceramics. A hydraulic seal is interposed between the piston and the cylinder. To simplify the assembly while allowing comparatively great tolerances, the seal is fitted at the end of the piston that is adapted to be mounted close to a pressure chamber within the system. The seal is provided with radially-extending projections which cause the piston to spring back by a roll-back effect.
Inventors
- 👤 Hans-Christof Klein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:35
CPC Classifications
F; F16; F16D; F16D65/00; F16D65/14; F16D65/16; F16D65/18; F16D65/38; F16D65/40; F16D65/52; F16D65/54; F16D65/78; F16D65/84; F16J; F16J1/00; F16J1/02; F16D2121/00; F16D2121/02; F16D2125/00; F16D2125/02; F16D2125/04; F16D2125/06; F16D2127/00; F16D2127/02; F16D2200/00; F16D2200/0034; F16D2200/0039
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
121 words
A piston-cylinder assembly for a wheel brake unit of a hydraulic brake system of an automotive vehicle comprising: a ceramic piston received in a cylinder of said wheel brake unit with radial clearance between said cylinder and said piston, said piston movable between a brake released position and a braked position in response to hydraulic pressure on said piston; a seal on said piston at an end thereof exposed to said hydraulic pressure in said cylinder including a sealing lip extending at an acute angle outwardly from said piston into sliding sealing engagement with said cylinder, said seal further including roll-back means engaging said cylinder for substantially returning said piston to said brake released position upon reduction of said hydraulic pressure.
Claim 2
Dependent Claim
121 words
A piston-cylinder assembly for a wheel brake unit of a hydraulic brake system of an automotive vehicle comprising: a ceramic piston received in a cylinder of said wheel brake unit with radial clearance between said cylinder and said piston, said piston movable between a brake released position and a braked position in response to hydraulic pressure on said piston; a seal on said piston at an end thereof exposed to said hydraulic pressure in said cylinder including a sealing lip extending at an acute angle outwardly from said piston into sliding sealing engagement with said cylinder, said seal further including roll-back means engaging said cylinder for substantially returning said piston to said brake released position upon reduction of said hydraulic pressure.
Claim 3
Dependent Claim
17 words
A piston-cylinder assembly as claimed in claim 1, in which the seal is prevulcanized to the piston.
Claim 4
Dependent Claim
26 words
A piston-cylinder assembly as claimed in claim 1, in which the piston comprises a central extension to which the seal is secured in positive engagement therewith.
Claim 5
Dependent Claim
16 words
A piston-cylinder assembly as claimed in claim 1, in which the cylinder contains a ceramic bushing.
Claim 6
Dependent Claim
26 words
A piston-cylinder assembly as claimed in claim 1, in which the piston includes at said end thereof an annular notch into which the seal is inserted.
Claim 7
Dependent Claim
17 words
A piston-cylinder assembly as claimed in claim 5, in which the notch is radially and axially open.
Claim 8
Dependent Claim
73 words
The piston-cylinder assembly as claimed in claim 1, wherein said roll-back means includes a plurality of resilient projections extending radially outwardly from said seal and being compressively engaged to said cylinder substantially against sliding movement relative thereto, whereby said projections axially deflect upon movement of said piston from said brake release position toward said braked position and resiliently return said piston substantially to the brake released position upon reduction of said hydraulic pressure.
Claim 9
Dependent Claim
42 words
The piston-cylinder assembly as claimed in claim 7, wherein said projections are axially spaced from said sealing lip defining an annual recess between said sealing lip and said projections, whereby said sealing lip is deflected into said recess by said hydraulic pressure.
Claim 10
Dependent Claim
74 words
A piston-cylinder assembly according to claim 1, wherein said seal is a hydraulic seal provided between the piston and the cylinder, the seal being fitted to the end of the piston that is adapted to be mounted close to a pressure chamber, in which there are a plurality of elastic centering webs fastened alongside of at least part of the length of the periphery of the piston to align the piston in the cylinder.
Claim 11
Dependent Claim
25 words
A piston-cylinder as claimed in claim 9, in which the centering webs are coupled to the hydraulic seal, the hydraulic seal comprising a ring seal.
Claim 12
Dependent Claim
41 words
A piston-cylinder assembly as claimed in claim 1, in which the cylinder comprises a central pin projecting into a cavity in the piston, and in that the seal abuts against the pin with at least one projection causing a roll-back effect.
Claim 13
Dependent Claim
22 words
A piston-cylinder assembly as claimed in claim 11, in which the projection is provided in a central through-bore of the ring seal.
Claim 14
Dependent Claim
31 words
A piston-cylinder assembly as claimed in claim 11, in which the seal is secured to the piston by means of an essentially cylinder-shaped, slotted sleeve portion which extends into the cavity.
Claim 15
Dependent Claim
26 words
A piston-cylinder assembly as claimed in claim 13, in which the sleeve portion comprises a sheet-metal element having an inwardly extending projection supported on the pin.
Claim 16
Dependent Claim
40 words
A piston-cylinder assembly according to claim 1, wherein said seal is a hydraulic seal provided between piston and cylinder, and in which the hydraulic seal comprises a ring seal including a prop ring which bridges tolerances in the cylinder diameter.
Claim 17
Dependent Claim
24 words
A piston-cylinder assembly as claimed in claim 15, in which the prop ring is located essentially within the main body of the ring seal.
Claim 18
Dependent Claim
26 words
A piston-cylinder assembly as claimed in claim 15, in which the prop ring is arranged on a step or in a groove of the piston respectively.
Claim 19
Dependent Claim
30 words
A piston-cylinder assembly as claimed in claim 17, in which the prop ring abuts with one of its radially extending end faces on a radially extending wall of the groove.
Claim 20
Dependent Claim
19 words
A piston-cylinder assembly as claimed in claim 15, in which the prop ring is vulcanized into the ring seal.
Claim 21
Dependent Claim
30 words
A piston-cylinder assembly as claimed in claim 15, in which there are elastic centering webs fastened alongside of at least part of the length of the periphery of the piston.
Claim 22
Dependent Claim
20 words
A piston-cylinder assembly as claimed in claim 20, in which the elastic centering webs are coupled to the ring seal.
Claim 23
Dependent Claim
26 words
A piston-cylinder assembly as claimed in claim 21, in which the prop ring contains through-recesses via which the centering webs are connected to the ring seal.
Claim 24
Dependent Claim
22 words
A piston-cylinder assembly as claimed in claim 21, in which the recesses are disposed at the outer rim of the prop ring.
References Cited (Backward Citations)
US2050736A
Cited
US2132730A
Cited
US2089471A
Cited
US2926976A
Cited
US3144256A
Cited
FR1462580A
Cited
US3971217A
Cited
US4170926A
Cited
US4417503A
Cited
DE2923934A1
Cited
US4364159A
Cited
US4498219A
Cited
US4510752A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-21 | 1993-02-20 | 1993-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-21 | 1997-02-20 | 1997-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-21 | 2001-02-20 | 2001-08-22 | $7700.00 | Window Closed / Lapsed |