Title of Invention

CLUTCH DISENGAGEMENT BEARING

Abstract

Release bearing, which is intended for a disconnectable clutch arranged between an internal combustion engine and a geared speed-change gearbox and is constructed as an inclined shoulder bearing, comprising: - a first, rotationally fixed bearing ring (2, 24), which is fixed in position on an actuating device (3,23) via an annular flange (13,33); - a second, revolving bearing ring (4, 22), on the annular flange (8, 28) of which a spring means of the disconnectable clutch is supported indirectly or directly; - anti-friction elements inserted in a cage (6, 26) between the bearing rings (2, 4; 22, 24); characterized in that at least a contact zone (10, 11, 12; 30, 31, 32) which is threatened by wear and/or a running surface (14, 15; 34, 35) of the release bearing (1, 21) has/have a hard material coating.

Full Text

FORM 2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See Section 10, rule 13) CLUTCH DISENGAGEMENT BEARING INA SCHAEFFLER KG of INDUSTRIESTRASSE HERZOGENAURACH, GERMANY, GERMAN Company 1-3, 91074 The following specification particularly describes the nature of the invention and the manner in which it is to be performed : - ORIGINAL 744/MUMNP/2004 The invention relates to a release bearing which is intended for a discormectable clutch which, in the installed state, is arranged between an internal combustion engine and a geared speed-change gearbox. The release bearing or the clutch release bearing is a constituent part of an actuating device with which the discormectable clutch can be engaged and disengaged. The release bearing, configured as an inclined shoulder bearing, comprises a first, rotationally fixed bearing ring, which is fixed in position on the actuating device by an annular flange. A second, revolving bearing ring of the release bearing likewise has an annular flange, which interacts indirectly or directly with a spring means of the disconnectable clutch. Anti-friction elements guided between the bearing rings of the release bearing are inserted into a cage. Background of the invention During actuation, the engagement and the disengagement of the disconnectable clutch, the clutch release bearing is displaced axially, irrespective of the functional position, the release bearing being acted on continuously by an axial force which is spring-loaded by the spring means of the discormectable clutch, in particular spring tongues of the clutch plate. During the actuating operation, a radial displacement of the supporting region of the plate spring on the release bearing begins. This relative movement has superimposed on it a further movement, in particular from the axial stroke of the disconnectable clutch and also rotational non-uniformity of the internal combustion engine. A purely metallic contact between the plate spring and the annular flange of the revolving bearing ring of the release bearing causes severe wear, intensifies the force necessary to actuate the disconnectable clutch and, moreover, can cause disadvantageous noise, which overall impairs driving comfort. DE 22 40 383 Al shows a clutch release bearing which avoids directly supporting the plate spring on the revolving bearing ring. For this purpose, the revolving inner bearing ring is assigned a stop ring which, in particular, is used to compensate for an axial offset between the rotating components of the disconnectable clutch and the actuating device. The contact surface between the rubbing partners, the stop ring and the contact surface, is provided with a friction-reducing coating. The known arrangement does not permit a defined position of the contact ring in the installed state, because of the floating arrangement on the rotating bearing ring. Disadvantageously, the known solution requires a relatively great deal of installation space both in the axial and in the radial direction, because of the components being produced by machining and because of the floating arrangement of the stop ring on the rotating bearing ring. The document DE 199 12 432 Al shows a release bearing on the revolving outer ring of which an adjusting ring is supported directly. The adjusting ring permits or compensates for fabrication tolerances or, in general terms, an axial offset or axial stroke of the disconnectable clutch. For this purpose, a spherical contact zone is provided between the outer ring and the adjusting ring, which means that these components can be pivoted with respect to each other. In this case, direct metallic contact is established between the adjusting ring and the outer ring. This arrangement intensifies the wear and can lead to the formation of frictional corrosion, associated with disadvantageous clutch cracking. With this arrangement, the lifetime required nowadays by vehicle manufacturers cannot be achieved either. Summary of the invention Taking the above-described disadvantages of the known solutions into account, it is an object of the invention to implement a release bearing which exhibits an improved lifetime without any influence on the required overall space and the extent of components and can be produced cost-effectively. This problem is solved in accordance with Claims 1 and 16. Accordingly, in order to improve the wearing resistance, at least a contact zone of the release bearing which is threatened by wear is provided with a hard material coating. In this case, the hard material coating is applied so thinly that this is neutral in terms of installation, that is to say has no influence on the overall space of the release bearing. The hard material coating ensures a high surface hardness and therefore prevents disadvantageous frictional corrosion, which increases the wear and the actuating force required to engage and disengage the disconnectable clutch. Furthermore, the hard material coating has the effect of an advantageous friction- reducing contact zone, frictional conditions being established in the contact zone which, because of the hard material layer, establish virtually constant frictional conditions over the lifetime of the disconnectable clutch. According to Claim 16, a method is claimed in which the hard material coating is applied by means of a plasma surface technique to the surfaces of the release bearing threatened by wear. Alternatively, the invention includes applying the hard material coating by means of laser pulsation. Further advantageous refinements of the invention according to Claim 1 are the subject of the dependent Claims 2 to 15. The hard material coating according to the invention can be transferred to all designs of release bearings. These include, in particular, release bearings in which the inner ring is connected in a rotationally rigid manner to the actuating device of the disconnectable clutch via an annular flange, and the associated revolving outer bearing ring interacts with the disconnectable clutch. In alternatively configured release bearings, the outer ring is rotationally rigidly connected to the actuating device, and the revolving inner ring is connected to the disconnectable clutch via the annular flange. Furthermore, the invention can be transferred to self- adjusting or self-setting release bearings. These release bearings are assigned an adjusting ring, which firstly interacts with the spring means of the disconnectable clutch and secondly is supported on the revolving bearing ring of the release bearing. In this case, a spherical contact zone is provided between the adjusting ring and the revolving bearing ring or, alternatively, both components are formed as spherical cup segments in the region of the contact zone. According to the invention, irrespective of the construction of the release bearing, provision is made to provide components or contact zones threatened by wear with a hard material coating. To this end, it is recommended in particular to coat the contact zone between the adjusting ring and the revolving bearing ring of a self-adjusting release bearing. Alternatively or additionally, the invention also includes providing the anti¬friction element running track of one or both bearing rings with a hard material coating. In addition to optimizing wear and preventing corrosion, this measure acts simultaneously to reduce friction. As a further advantageous measure, the invention permits further highly stressed regions of the release bearing to be provided partially with a hard material coating. Suitable for this purpose is, in particular, the annular flange which has a force-fitting connection to the spring means, the plate spring of the disconnectable clutch. In this case, both contact zones on the spring means and on the annular flange are preferably coated. As an alternative to partial coating, it is recommended to provide all the components of the release bearing with a hard material coating. In this case, complicated covering of the uncoated zones is dispensed with. At the same time, the complete hard material coating of all the components of the release bearing has the effect of effective corrosion prevention. The hard material coating provided in the sense of the invention is different coatings. These include, in particular, modified DLC (diamond-like carbon) layers, which are distinguished by high hardness, high wear resistance and friction-reducing properties. Also suitable is a hard material coating which comprises hydrocarbon layers with proportions of tungsten with the designation W-C:H. The hard material coating used can advantageously be titanium niobium nitride or else titanium niobium oxynitride. A further hard material coating that can be used consists of tetrahedral carbon without hydrogen. In addition, chromium nitrite layers are suitable, in which nanodispersions of chromium carbon CrC are inlaid. This hard material coating is distinguished by particular hardness and wear resistance. At the same time, a hard material coating including chromium nitrite exhibits a high adhesive capacity to the component which is specifically intended to be coated. The hard material coating can also be configured as a multi-ply layer. Suitable in particular for this purpose is W-C:H + aC:H. This multi-ply layer has little friction and, at the same time, is resistant to wear. In addition, what is known as a supernitrite layer is suitable as a hard material coating with which, according to the invention, the entire release bearing or, specifically, contact zones are coated. In order to meet the requirement for the different functional surfaces of the release bearing, the invention further includes providing the supporting surfaces or thrust surfaces of the bearing rings, which interact with the actuating device or the spring means of the disconnectable clutch, with a hard material coating exhibiting high wear resistance. In order nevertheless to achieve extremely low friction in the Spherical contact zone between the adjusting ring and The revolving bearing ring, it is proposed to coat with a hard material layer that is modified with regard to Optimizing friction, the coatings preferably being carried out in one operation. In order to achieve the highest bearing loading with Regard to temperature and to reduce the bearing Friction, according to the invention at least the running track of the revolving bearing ring is provided with a hard material coating. This measure ensures High bearing temperatures and at the same time improves the emergency running characteristics in the event of a lack of lubrication. Given the specific coating of the annular flange with a hard material layer which, in the installed state, has A force-fitting connection to the spring means of the disconnectable clutch, it is advantageously possible to dispense with a separate thrust washer, which is inserted into this contact zone in order to optimize wear and friction. A hard material coating, applied to individual anti- friction bearing components such as running rings, Anti-friction elements and highly loaded contact zones, additionally achieves a reduction in the rolling friction, apart from a higher temperature load-bearing ability, wear resistance, emergency running characteristics, which overall increases the useful life of the release bearing, even for high stresses. The hard material coating according to the invention is preferably applied in a thickness of Brief description of the drawings Two drawings show two exemplary embodiments of the invention, which will be described in more detail in The following text. In the drawings: Figure 1 shows a release bearing in a half section, with a rotationally rigidly arranged inner ring and a revolving outer ring, on which an adjusting ring is supported; Figure 2 shows an alternatively configured release bearing, comprising a rotationally rigidly arranged outer ring, which is combined with a revolving inner ring, on which an adjusting Ring is supported. Detailed description of the drawings The release bearing 1 depicted in figure 1 is illustrated in the installed state. In this case, an inner bearing ring 2 is rotationally rigidly connected to an actuating device 3, which encloses a drive shaft, not depicted in figure 1, which connects an internal combustion engine to a geared speed-change gearbox. In order to engage and disengage the actuating device 3, this can be displaced axially, identified by the double arrow. Between the inner bearing ring 2 and an associated further outer bearing ring 4, anti-friction elements 5 are guided, which are arranged spaced apart in a cage 6. On the outside, supported on the outer bearing ring 4, there is an adjusting ring 7, which forms an annular flange 8 which is oriented radially inwards and on which a spring means 9, in particular a Plate spring, belonging to the disconnectabie clutch is supported with a force fit. The result of this arrangement is that both the adjusting ring 7 and the outer bearing ring 4 are arranged so as to revolve with the disconnectabie clutch. In order to compensate for a clutch stroke or an axial offset between the disconnectabie clutch and the actuating device 3, the adjusting ring 7, in conjunction with the outer bearing ring 4, is capable of compensating for this offset. For this purpose, between the components, the adjusting ring 7 and the outer bearing ring 4, a spherical contact zone 10 is provided, which makes it possible for the adjusting ring 7 to execute a limited pivoting movement with respect to the outer bearing ring 4, according to the double arrow. The release bearing 1 has different functional surfaces which are subjected to high stress. As a measure to reduce the wear, in order for example to prevent disadvantageous frictional corrosion formation, the invention provides for at least the highly stressed contact zones of the release bearing 1 to be provided with a hard material coating. For this purpose, the contact zone 10 between the adjusting ring 7 and the outer bearing ring 4 is preferably coated. Furthermore, it is recommended to coat the contact zone 11 between the annular flange 8 of the adjusting ring 7 and the spring means 9 with a hard material layer. Furthermore, the contact surface 12 that is established between the annular flange 13 and the actuating device 3 is suitable for coating. In addition, it is recommended to provide the running surfaces 14, 15 between the anti-friction elements 5 and the inner bearing ring 2 and, respectively, between the anti¬friction elements 5 and the outer bearing ring 4 with a hard material coating. As an alternative to partial coating of highly stressed contact zones 10,11,12 or of the running surfaces 14, 15, it is recommended to provide the release bearing with a suitable hard material coating on all sides. The release bearing 21 depicted in Figure 2 comprises an inner bearing ring 22 and an outer bearing ring 24 assigned to the actuating device 23. Between the bearing rings 22, 24, anti-friction elements 25 configured as balls are guided in the cage 26. Supported on the inner bearing ring 26 is the adjusting ring 27 which, in the installed state, is connected via the annular flange 28 to the disconnectable clutch, not depicted in Figure 2. The adjusting ring 27, positioned captively on the inner bearing ring 22 by means of a retaining element 29, together with the inner bearing ring 22 forms a spherical contact zone 30, which is provided with a suitable hard material coating in order to optimize wear and friction. The hard material coating is also preferably applied to the contact zones 31, 32, via which the annular flange 28 of the adjusting ring 27 is supported on the disconnectable clutch and the outer bearing ring 24 is supported by its annular flange 33 on the actuating device 23. Further highly loaded contact zones, which are advantageously protected by means of a hard material coating, are the Reference numbers 1 Release bearing 2 Bearing ring (inner) 3 Actuating device 4 Bearing ring (outer) 5 Anti-friction element 6 Cage 7 Adjusting ring 8 Annular flange 9 Spring means 10 Contact zone 11 Contact zone 12.Contact zone 13 Annular flange 14 Running surface 15 Running surface 21 Release bearing 22 Bearing ring (inner) 23 Actuating device 24 Bearing ring (outer) 25 Anti-friction element 26 Cage 27 Adjusting ring 28 Annular flange 29 Retaining element 30 Contact zone 31 Contact zone 32 Contact zone 33 Annular flange 34 Running surface 35 Running surface Claim: 1. Release bearing, which is intended for a disconnectable clutch arranged between an internal combustion engine and a geared speed-change gearbox and is constructed as an inclined shoulder bearing, comprising: - a first, rotationally fixed bearing ring (2, 24), which is fixed in position on an actuating device (3,23) via an annular flange (13,33); - a second, revolving bearing ring (4, 22), on the annular flange (8, 28) of which a spring means of the disconnectable clutch is supported indirectly or directly; - anti-friction elements inserted in a cage (6, 26) between the bearing rings (2, 4; 22, 24); characterized in that at least a contact zone (10, 11, 12; 30, 31, 32) which is threatened by wear and/or a running surface (14, 15; 34, 35) of the release bearing (1, 21) has/have a hard material coating. 2. Release bearing as claimed in claim 1, which is provided with a rotationally rigidly arranged inner ring (2) and a revolving outer ring (4), an annular flange of the outer ring (4) interacting indirectly or directly with the disconnectable clutch. 3. Release bearing as claimed in claim 1, wherein the outer ring (24) is arranged to be rotationally rigid and of which the inner ring (22) is arranged so as to revolve, the inner ring (22) interacting with the spring means of the disconnectable clutch via an annular flange. 4. Release bearing as claimed in claim 1, which is constructed as a self-adjusting release bearing (1, 21), on the revolving bearing ring (4, 22) of which an adjusting ring (7, 27) is supported, and an annular flange (8, 28) of the adjusting ring (7, 27) interacts with the spring means of the disconnectable clutch. 5. Release bearing as claimed in claim 4, wherein at least one component having a hard material coating in a spherical contact zone (10, 30) between the revolving bearing ring (4, 22) and the adjusting ring (7,27). 6. Release bearing as claimed in claim 1, wherein at least one component having a hard material coating in the contact zone (11, 31) between the spring means (9) of the disconnectable clutch and the annular flange (8, 28) of the adjusting ring (7,27). 7. Release bearing as claimed in claim 1, in which at least the running surface (15, 22) intended for the anti-friction elements (5, 25) has a hard material coating. 8. Release bearing as claimed in claim 1, of which the contact zone (10,11, 12; 30, 31, 32) and/or the running surface (14, 15; 34, 35) has/have a DLC coating as a hard material coating. 9. Release bearing as claimed in claim 1, in which the hard material coating provided is a hydrocarbon layer with proportions of tungsten. 10. Release bearing as claimed in claim 1, wherein the hard material layer provided being a titanium niobium nitride or a titanium niobium oxynitride layer. 11. Release bearing as claimed in claim 1, of which the contact zone (10,11, 12; 30, 31, 32) has applied to it a hard material coating which consists of tetrahedral carbon without hydrogen. 12. Release bearing as claimed in claim 1, of which the hard material coating includes chromium nitride layers in which nanodispersions of CrC are inlaid. 13. Release bearing as claimed in claim 1, wherein it comprises a multi-ply layer consisting of W-C: H and a-C:H as a hard material coating. 14. Release bearing as claimed in claim 1, in which the contact surface (10, 11, 12; 30, 31, 32) has a hard material coating designated a supernitrite layer. 15. Release bearing as claimed in claim 1, in which the hard material coating on at least one contact surface (10, 11, 12; 30, 31, 32) and/or on at least one running surface (15,22) is applied in a thickness of 16. Method for implementing a coating on a release bearing as claimed in claim 1, characterized in that, by means of a plasma surface technique or laser pulsation, a hard material coating is applied at least to a contact zone (10, 11, 12; 30, 31, 32) threatened by wear and/or a running surface (15, 22) of the release bearing (1,21). HIRAL CHANDRAKANT JOSHI AGENT FOR INA SCHAEFFLER KG Dated this 20th day of December, 2004.

Documents:

744-mumnp-2004-cancelled pages(02-03-2006).pdf

744-mumnp-2004-claims(granted)-(02-03-2006).doc

744-mumnp-2004-claims(granted)-(02-03-2006).pdf

744-mumnp-2004-correspondence(24-12-2006).pdf

744-mumnp-2004-correspondence(ipo)-(11-09-2006).pdf

744-mumnp-2004-form 1(30-11-2006).pdf

744-mumnp-2004-form 13(30-11-2006).pdf

744-mumnp-2004-form 18(05-04-2005).pdf

744-mumnp-2004-form 18(30-11-2006).pdf

744-mumnp-2004-form 1a(21-12-2004).pdf

744-mumnp-2004-form 2(granted)-(02-03-2006).doc

744-mumnp-2004-form 2(granted)-(02-03-2006).pdf

744-mumnp-2004-form 3(30-11-2006).pdf

744-mumnp-2004-form 5(20-12-2004).pdf

744-mumnp-2004-form 5(30-11-2006).pdf

744-mumnp-2004-form-pct-isa-210(02-03-2006).pdf

744-mumnp-2004-power of attorney(30-11-2006).pdf