192 clutches and power-stop control – Clutches – Operators
Reexamination Certificate
2002-03-20
2004-02-03
Rodriquez, Saul (Department: 3681)
192 clutches and power-stop control
Clutches
Operators
C192S11000B
Reexamination Certificate
active
06684997
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates, in general, to a clutch release bearing, and more particularly to a clutch release bearing for use in a clutch mechanism for motor vehicles.
A clutch release bearing is typically intended for actuation of a clutch mechanism, e.g. separating clutch, disposed between the internal combustion engine and a gearbox, and is configured as a tapered roller bearing which includes a revolving outer bearing ring, a non-rotatable inner bearing ring, and rolling members, received in a cage and guided between the bearing rings. Supported against the outer ring is an adjustment ring, which establishes a connection between a disk spring of the clutch mechanism and the release bearing, whereby the disk spring bears directly on a skirt of the outer ring at the side of the adjustment ring confronting the clutch mechanism. The adjustment ring is configured to allow a relative movement of the adjustment ring and the outer ring so as to implement a self-adjusting or self-aligning release bearing.
Such a release bearing is able to compensate shocks generated by axial misalignment with the disk spring that is connected directly to the clutch mechanism. The axial shocks, caused by the disk spring and reinforced by the operation of the internal combustion engine, increase wear and thus reduce the service life of the release bearing.
German Pat. No. 199 12 432 A1 describes a release bearing with a revolving outer ring for direct support of an adjustment ring. In their contact zone, the outer ring and the adjustment ring have complementary calotte-shaped segments to allow a relative movement. The outer ring of the release bearing as well as the adjustment ring are made of steel. As a consequence, rust formation caused by friction can be experienced, resulting in greater wear. High wear results in annoying noise and triggers the so-called clutch judder that adversely affects the overall riding comfort, so that the service life of these release bearings is insufficient to meet the demands by vehicle manufactures.
It would therefore be desirable and advantageous to provide an improved release bearing, which obviates prior art shortcomings and which exhibits a long service life, is maintenance-free and inhibits noise while still being reliable in operation and cost-efficient to produce.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, a release bearing includes a rolling-contact bearing having a non-rotatable inner ring, a rotating outer ring, and plural rolling members located between the inner and outer rings; an adjustment ring having a ring flange for abutment against a disk spring of a clutch mechanism; and a sliding element made of bearing material and disposed in a support zone, which is defined between complementary calotte-shaped portions of the outer ring and the adjustment ring so that the adjustment ring and the outer ring are movable relative to one another for effecting a self-adjustment of the release bearing.
The present invention resolves prior art problems by providing a sliding element in the support zone or contact zone between the adjustment ring and the revolving outer ring of the release bearing. The sliding element is suitably made of a bearing material or appropriate friction-reducing and wear-resistant material which is maintenance-free to ensure a long service life. As a result of the reduction in friction, the self-adjusting feature of the components, outer ring and adjustment ring, is significantly improved. The optimized self-adjustment is further able to significantly dampen the axial shocks transmitted via the clutch mechanism into the release bearing. The provision of a sliding element eliminates a direct contact of the steel parts, adjustment ring and outer ring, and this prevents friction-based rust formation. By sandwiching the sliding element in the support zone between the outer ring and adjustment ring, the latter components are effectively decoupled from one another so that noise development is suppressed. A direct contact of the adjustment ring upon the outer ring is suitably avoided to thereby ensure a maintenance-free, low friction and sat the same time damping self-adjustment between the mutually moving components, adjustment ring and outer ring. The sliding element can be connected to either one of the carriers, i.e. outer ring or adjustment ring, without requiring any modification of the carrier that is selected to bear against the sliding element, so that existing installation space can be used. Support of the adjustment ring on the outer ring permanently eliminates friction-based rust formation.
It is to be understood by persons skilled in the art that the term “carrier” used in the description to refer to the outer ring or to the adjustment ring of the release bearing.
Wear of the spherical or calotte-shaped portions in the support zone between the sliding element and the outer ring or adjustment ring is significantly reduced compared to conventional self-adjusting release bearings. Moreover, clutch judder is effectively prevented which has a positive effect to reduce noise development. A sliding element according to the present invention can be fabricated in great numbers and does not require special handling for installation or securement to the adjustment ring or outer ring of the release bearing.
According to one embodiment of the present invention, the sliding element may be connected to the outer ring of the release bearing. A largest possible contact surface can be realized, when the sliding element embraces the entire side of the outer ring and is extended to an area shy of the contour of the non-rotatable inner ring at formation of a slight annular gap. In this way, the rotating outer ring can be optimized with respect to size and weight and may have a width which is substantially limited to the provision of a suitable raceway for the rolling members. At the same time, the sliding element ensures on the side confronting the adjustment ring a large contact zone or enlarged support zone for the adjustment ring. Thus, a sufficiently large contact zone or support zone between the mutually movable components is realized even at extremely tilted positions. As an alternative, the sliding element may also be connected directly to the adjustment ring to form a unitary structure which has calotte-shaped portions to complement the outer contour of the rotating outer ring of the release bearing. In either case, the large-area contact of the sliding element upon the adjustment ring or outer ring results in a sufficient support in each and every position, i.e., also when the adjustment ring occupies an extremely tilted disposition. At the same time, the large-area contact of the sliding element ensures a reduced surface pressure so that the strength and rigidity of the sliding element is not adversely affected.
According to another feature of the present invention, the sliding element may also be configured in segments, instead of a continuous contact, for resting upon the outer ring or adjustment ring. In this way, the adhesion of the sliding element is improved because tension as a consequence of different coefficients of thermal expansion between the different materials of the adjustment ring or outer ring, and the sliding element is effectively eliminated. Of course, the sliding element may also be configured with a longitude slot or groove, which coincides with the symmetry axis, in order to compensate varying coefficients of thermal expansion. Instead of one slot or groove, also several slots or grooves may be provided about the circumference of the sliding element and formed alternately on the inside or outside of the sliding element or extend through the wall of the sliding element. Any suitable configuration of the slot or slots is conceivable, i.e., straight, meander-shaped or slanted.
The production costs for making a sliding element according to the present invention can be reduced, when employing an injection molding process. This process can also be used to incorporat
Dittmer Steffen
Klöpfer Bernhard
Winkelmann Ludwig
Feiereisen Henry M.
INA-Schaeffler KG
Rodriquez Saul
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