192 clutches and power-stop control – Clutches – Operators
Reexamination Certificate
2001-01-23
2001-12-11
Marmor, Charles A (Department: 3681)
192 clutches and power-stop control
Clutches
Operators
C192S090000, C192S098000
Reexamination Certificate
active
06328148
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to fluid-operated clutch release mechanisms, and more particularly to improvements in hydraulic mechanisms which can be utilized with advantage to release clutches, such as friction clutches, in the power trains of motor vehicles. Still more particularly, the invention relates to improvements in hydraulic clutch release mechanisms of the type wherein a cylinder-piston unit employs a cylindrical housing and an internal guide which defines with the housing an annular plenum chamber for a reciprocable piston adapted to actuate the clutch by way of a release bearing or the like.
A hydraulic clutch release mechanism which is disclosed in published German patent application Serial No. 196 35 101 A1 employs a piston which is arranged to change the condition of a diaphragm spring in a friction clutch of the character often employed in the power trains of motor vehicles. The piston of the release mechanism carries a lip seal which is secured thereto by a connector. The latter is anchored in or recessed into the lip seal, and an axially extending leg of such connector is recessed into the peripheral surface of the piston.
A drawback of the just described conventional clutch release mechanism is that the seal is apt to jam and/or to be tilted in the plenum chamber; this exerts an adverse influence upon the guidance of the piston and can affect the ability of the piston to actuate the clutch.
OBJECTS OF THE INVENTION
An object of the present invention is to provide a hydraulic clutch release mechanism which is more reliable and lasts longer than heretofore known release mechanisms including that disclosed in the aforementioned German patent application Serial No. 196 35 101 A1.
Another object of the invention is to provide a novel and improved piston-seal combination for use in a hydraulic clutch release mechanism.
A further object of the invention is to provide a novel and improved arrangement for coupling the seal to the piston in a hydraulic clutch release mechanism.
An additional object of the invention is to provide a clutch release mechanism wherein the seal is not likely to leave its desirable optimum position relative to the piston.
Still another object of the invention is to provide a novel and improved method of securing the seal to the piston in the plenum chamber of a hydraulic clutch release mechanism.
A further object of the invention is to provide a novel and improved piston for use in the above out-lined hydraulic clutch release mechanism.
Another object of the invention is to provide a novel and improved seal for use in a clutch release mechanism of the above outlined character.
An additional object of the invention is to provide a novel and improved retainer which couples the seal to the piston in a hydraulic clutch release mechanism.
Still another object of the invention is to provide a power train which can be utilized in a motor vehicle and employs the above outlined improved clutch release mechanism.
SUMMARY OF THE INVENTION
The instant invention is embodied in a clutch release mechanism which comprises a cylinder-piston unit including a cylindrical housing having an internal surface, a centrally located guide having an external surface spacedly surrounded by the internal surface of the housing and defining with such internal surface a plenum chamber, and a piston which has spaced-apart first and second end portions and is reciprocable in the plenum chamber. The improved clutch release mechanism further comprises a seal which is disposed in the chamber at one end portion of the piston and includes a first section (such as an annular lip) contacting the internal surface of the housing, a second section (such as an annular lip) which contacts the external surface of the guide, and a third section which form-lockingly engages the one end portion of the aforementioned piston, and an annular retainer which is affixed to the piston and includes a portion form-lockingly engaging the seal.
The improved release mechanism can further comprise means (such as a bearing) for operatively connecting the other end portion of the piston with a friction clutch in a motor vehicle, e.g., with the prongs of a diaphragm spring.
The third section of the seal can include a first part which form-lockingly engages the one end portion of the piston and a second part which form-lockingly engages the aforementioned portion of the retainer. The retainer or the second part of the third section of the seal can be provided with an annular groove which extends substantially radially of the housing, and the other of these components is then provided with an annular bead which extends into and preferably fills the groove. It is presently preferred to provide the bead on the retainer.
The one end portion of the piston can be configurated in such a way that it includes mutually inclined first and second surfaces which preferably make an angle at least approximating 90°; the first part of the third section of the seal is then provided or can be provided with mutually inclined third and fourth surfaces which respectively abut (such as lie flush against) the first and second surfaces.
The one end portion of the piston or the first part of the third section of the seal can be provided with an undercut recess, and the other of these components is then provided with a portion which at least substantially fills the undercut recess. For example, the recess can be provided in the one end portion of the piston.
Furthermore, the retainer or the piston can be provided with at least one projection which is received in a recess of the other of these components. The at least one projection can be received in the recess by snap action. Furthermore, the at least one projection can be received in the recess with at least some play as seen in the axial direction of the housing.
The one end portion of the piston can constitute a stepped cylinder having a first annular portion slidable along the guide and a second annular portion which is axially and radially offset relative to the first portion and is slidable along the housing.
Furthermore, the one end portion of the piston or the aforementioned portion of the retainer can be provided with an undercut annular groove for a projection which is complementary to the undercut annular groove and is provided on the seal.
The retainer can be affixed to the piston in any one of a plurality of different ways, e.g., by crimping, beading or burnishing. It is also possible to bond the retainer to the piston (e.g., by welding, soldering, brazing and/or by resorting to a suitable adhesive substance).
The retainer can be made of or can contain steel, aluminum or another suitable metallic material. It is also possible to make the retainer, at least in part, of a suitable plastic material. Furthermore, the retainer can constitute an extrusion, it can constitute a deep drawn article, or it can constitute a converted blank which has undergone a material removing treatment, e.g., in a lathe.
The retainer can be secured to the piston in a number of suitable ways. A presently preferred mode includes the utilization of a coupling which is carried by the piston and at least a portion of which extends into an opening of the retainer. Such portion of the coupling extends or can extend substantially radially of the housing, and the piston can be provided with a recess for the aforementioned portion of the coupling; this portion can extend into the recess of the piston with at least some freedom of movement as seen in the axial direction of the housing. Furthermore, the aforementioned portion of the coupling can be made, at least in part, of a resilient material and can be mounted in the at least one opening of the retainer and in the recess of the piston in prestressed condition (as seen radially of the piston).
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved clutch release mechanism itself, however, both as to its construction and the modes of assembling, ins
Meyer Gerhard
Winkelmann Ludwig
Darby & Darby
LuK Lamellen und Kupplungsbau GmbH
Marmor Charles A
Rodriguez Saul
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