Seal for a joint or juncture – Seal between relatively movable parts – Piston ring or piston ring expander or seat therefor
Reexamination Certificate
1998-06-08
2001-03-06
Knight, Anthony (Department: 3626)
Seal for a joint or juncture
Seal between relatively movable parts
Piston ring or piston ring expander or seat therefor
C277S439000, C277S566000, C277S575000
Reexamination Certificate
active
06196552
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a seal assembly and more particularly to a seal assembly especially suitable for use as the seal element in an annular hydraulic cylinder and piston assembly such, for example, as a concentric sleeve cylinder assembly for operating the throw-out bearing of a vehicular clutch.
In a concentric slave cylinder an annular piston is slidably positioned in an annular cylindrical bore and an annular seal element is positioned in the annular bore and acts in association with the piston to define a hydraulic fluid pressure chamber on the power side of the piston. Whereas various annular seal designs have been proposed for use in concentric slave cylinders, each of the prior art designs has suffered from one or more disadvantages. Specifically, the prior art seals have had an excessively complicated and expensive construction; and/or the prior art seals have provided only a relatively short product life; and/or the prior art seals have had a tendency to cock in the cylindrical bore so as to complicate their insertion in the bore and derogate the sealing performance of the seal in the bore; and/or the prior art seals have generated excessive friction and squirming as between the seal and the bore; and/or the prior art seals have exhibited an excessive system hysteresis effect.
SUMMARY OF THE INVENTION
This invention is directed to a concentric seal that is especially suitable for use in a concentric slave cylinder.
This invention is more specifically directed to a concentric seal that is simple and inexpensive in construction; that performs satisfactorily over a long product life; that is resistant to cocking in the cylinder bore; that generates a minimum of friction between the seal and the cylindrical bore; and that reduces the system hysteresis effect.
The seal element of the invention comprises a seal assembly including an annular insert structure formed of a rigid material and an annular seal member formed of an elastomeric material and bonded to the insert structure. The insert structure includes an annular outer structure, an annular inner structure, left and right annular radial faces, and a continuous annular groove in the right radial face. The elastomeric annular seal member fills the groove in the insert and extends to the right of the insert structure to form a seal structure defining an outer annular sealing surface having a relaxed configuration positioned radially outwardly and to the right of the annular outer insert structure and an inner annular sealing surface having a relaxed configuration radially inwardly and to the right of the annular inner insert structure. This basic seal design provides a simple and inexpensive construction; minimizes cocking of the seal assembly in the bore; minimizes friction as between the seal and the bore; and reduces the system hysteresis effect.
According to a further feature of the invention, the insert structure further defines a plurality of circumferentially spaced holes extending axially through the insert structure from the groove to the left annular radial face and the elastomeric material fills the holes. This specific arrangement ensures a positive bonding of the elastomeric material to the rigid material of the insert structure.
According to further feature of the invention, the insert structure further defines a continuous annular groove in the left annular radial face of the inside structure; the holes extend between the left and right grooves; and the elastomeric material fills the left groove. This specific interrelationship between the elastomeric material and the structure of the insert further enhances the bond between the elastomeric material and the insert.
According to further feature of the invention, the insert structure has an I-beam cross-sectional configuration including an outer annular flange structure forming the annular outer structure, an inner annular flange structure forming the annular inner structure, and an annular web structure extending radially between the inner and outer flange structures and having a left face coacting with left portions of the inner and outer annular flange structures to form the left groove and coacting with right portions of the inner and outer annular flange structure to form the right groove; and the holes extend through the web structure and connect with the left and right grooves. This specific I-beam construction for the insert structure provides strength to the assembly and facilitates the bonding of the elastomeric material to the insert structure.
In disclosed embodiment of the invention, the seal structure is free to flex in a sealing scenario to allow the inner annular sealing surface to assume a working position in approximate axial alignment with the radially inner annular surface of the inner flange structure and allow the outer annular sealing surface to assume a working position in approximate axial alignment with the radially outer annular surface of the outer flange structure, and the seal structure defines an annular groove between the inner and outer sealing surfaces to facilitate flexing movement of the inner and outer sealing surfaces to their working positions.
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Print showing concentric slave cylinder seal produced by FTE FAHKRZEUGTECHNIK EBERN GmbH for General Motors Opel Vetrex, Mar. 1996.
Iyer Rajiv
Peterson David C.
Automotive Products (USA) Inc.
Beres John L.
Knight Anthony
Young & Basile P.C.
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