GB2073353A

GB2073353A - Clutch release bearing assembly

Info

Publication number: GB2073353A
Application number: GB8111018A
Authority: GB
Original assignee: Valeo SE
Current assignee: Valeo SE
Priority date: 1980-04-08
Filing date: 1981-04-08
Publication date: 1981-10-14
Also published as: ES8202622A1; ES501143A0; BR8102103A; GB2073353B; PL230565A1; DE3114011C2; IT1145962B; DE3114011A1; SU1240368A3; PL135724B1; MX152433A; IT8112490A0

Abstract

The invention relates to a clutch release bearing assembly in which the operating member (10) intended to be subjected to the action of the clutch release fork (11) is made of synthetic material, and for supporting the clutch release fork a metal support element (17) is provided which is disposed axially between the transverse flange (14) on the operating member (10) and the driving element (12) which acts on the clutch release means. The flange (14) has passages (18) providing access to the support element (17) for the clutch release fork (11), and the support element (17) comprises a simple flat or substantially flat washer. The invention is particularly applicable to self-centering clutch release bearings for motor vehicles. <IMAGE>

Description

SPECIFICATION Clutch release bearing The present invention relates generally to clutch release bearings, particularly for motor vehicles.

Generally speaking, a clutch release bearing substantially comprises an operating member intended to be subjected to the action of a control means such as a clutch release fork, a driving element which is intended, under the action of the operating member, to act on the release means of the clutch in question, and connection means axially fastening the driving element to the operating member.

In practice the operating member usually has a transverse flange on one side of which is disposed the control means and on the other side of which is disposed the driving element.

The present invention relates more particularly to clutch release bearings of this kind in which the operating member is made from synthetic plastics material.

In order to protect an operating member of this kind made from a synthetic material from the action of the control means, which because of the contact pressure developed whenever the control means is operated, can cause rapid deterioration of the assembly, it is usual to provide a specific metal support element for axially supporting the control means.

This metal support element usually consists of a lining plate which lines the flange of the operating member on the opposite side to that on which the driving element is disposed.

It has already been proposed to locate the support element axially between the driving element and the flange of the operating member.

This is the case, for example, in U.S. Patent No. 3,390,927, in French Patent Application No. 77 14977 and published under No.

2,391,392, and in at least some of the embodiments described in French Patent Application No. 79 22532 filed on the 10th September 1979.

In U.S. Patent No. 3,390,927 the support element, to which access is provided for the control means through the flange of the operating member-for which purpose this flange is provided locally with passages-has in practice a right-angled profile in axial section, which results from the fact that, since the clutch release bearing in question is not a selfcentering clutch release bearing, its driving element is fitted on a cylindrical bearing surface necessarily formed on an axial portion of the support element.

Apart from the fact that an arrangement of this kind would not be suitable for self-centering clutch release bearings, for which omnidirectional freedom of movement must be allowed radially for the driving element relative to the operating member, it leads to a relatively complex general configuration of the support element and is therefore more expensive because the heat treatment to which it must be subjected in order to improve its resistance to wear cannot be applied before it is shaped.

In French Patent No. 77 14977 the support element is in one piece with one of the components of the driving element, and this has the consequence that, as in the previous case, this part has a relatively complex overall shape and is therefore expensive.

In French Patent No. 79 22532 the support element is a separate part from the driving element, but for specific reasons due to particular conditions of application this support element has, as in the previous cases, a relatively complex overall shape and is therefore relatively expensive.

The present invention provides a release bearing which avoids these disadvantages and has advantages of its own which will be appreciated from the description which follows.

According to the present invention, there is provided a clutch release bearing of the kind comprising an operating member of synthetic material, which is intended to be subjected to the action of a control means such as a clutch release fork, and which is provided with a transverse flange, a metal support element adapted to support the control means, a driving element which is intended, under the action of the operating member, to act on the release means of a clutch, and connection means axially connecting the driving element to the operating member, the support element being disposed axially between the driving element and the flange of the operating member, and the flange being provided locally with passages to allow access of the control means to the support element, the clutch release bearing being characterised in that the support element consists of a simple, substantially flat washer.

This arrangement, which is particularly suitable for self-centring clutch release bearings in which the driving element is free to move radially in all directions in contact with the support element, is particularly economical to put into practice.

The support element is in fact a simple part, of any shape, which is advantageously cut out directly from a previously treated blank and which, since it does not require the application of any heat treatment after it has been formed, has a relatively low cost price.

In practice, the washer constituting the support element may be for example strictly flat.

As an alternative, it may be provided locally with one or more bosses which are formed during the actual cutting-out process and which extend axially into corresponding passages in the flange of the operating member, in erder to provide support for the control means and thus to adjust the axial dimension of the assembly to a predetermined value, and also to lock it against rotation.

Furthermore, in cases where some measure of axial guidance needs to be provided between the control means and the release bearing, this guidance may very easily be provided by the operating member of the release bearing, which member, being made of synthetic material by simple moulding, readily lends itself to the production of the more or less complex shapes suitable for this purpose.

In practice, to achieve this guidance, each passage in the flange of the operating member is preferably edged with an axial lug or collar along at least part of at least one of its edges. The presence of this axial lug or collar, bearing in mind the fact that it is additional to the axial thickness of the flange, provides reliable guiding for the control means.

Finally, since the control means passes through the flange of the operating member in order to contact the associated support element the axial thickness of this flange advantageously does not form part of the axial dimension of the assembly.

Briefly, other conditions being equal, the clutch release bearing according to the invention is particularly compact and economical to produce.

For at least some applications it may be desirable to improve the axial retention of the washer used to form the support element.

Although in fact the axial retention of this support element is effected positively by the flange of the operating member on the opposite side to that where the driving element is situated, this is not the case on the driving element side, where the axial retention of the support element depends on the connection means axially fastening the driving element to the operating member, these means usually having an axial capacity of elastic deformation which, particularly in the case of a self-centering release bearings, is compatible with maintaining the self-centered driving element in position.

The consequence is that under the action of the control means, and particularly if this action does not take place exactly symmetrically in relation to axial plane of the assembly, the support element may during a declutching operation be subjected to a rocking movement causing it to be positioned slightly askew in relation to the axis of the assembly, so that the driving element, being consequently subjected to a similar rocking movement, no longer bears on a circularly uniform manner against the clutch release means, which is clearly prejudicial to the working and functioning of the assembly.

According to a development of the present invention it is proposed to associate with the support element, on that side of the flange of the operating member which faces the driving element, axial retention means adapted to ensure positive axial retention of the support element.

In a first embodiment the flange of the operating member is provided with an axial collar on its outer periphery, and the retention means in question comprise at least two lugs disposed radially on the outer periphery of the washer forming the support element, while for each of the lugs thus provided on the support element, there is provided on the axial collar of the flange of the operating member, at a distance from this flange, a transverse shoulder which faces axially towards the flange and which is in contact with one such lug.

With this arrangement, the washer forming the support element is simply clipped into position.

As an alternative, the axial retention means comprises a web which is integral with the operating member and which is moulded over some or all of the support element.

In such a case the washer forming the support element is disposed in advance in the mould in which the operating member is moulded.

According to another variant, for the axial retention of the support element on the driving element side there is associated with the support element an annular retaining part which bears axially against the operating member and holds the support element in contact with the flange thereof.

In all cases axial retention of the washer forming this support element is effected positively, in both directions, so that this washer is prevented from displacement during a declutching operation and thus correct operating conditions are ensured for the assembly.

When this axial retention of the washer forming the support element is effected by means of a separate retaining part, in one particular embodiment this part comprises a washer which is interposed axially between the driving element and the support element.

In this embodiment therefore, which is more particularly intended for the case where the clutch release bearing in question is a selfcentering clutch release, the retaining part used for the support element may advantageously serve a dual function: on the one hand it ensures positive axial retention of the support element and on the other hand because of the nature of the material of which it is made, and which is selected accordingly, it defines the conditions of friction under which the self-centering action of the driving element is actually maintained.

Moreover, at least in some cases, in a selfcentering clutch release bearing of this kind, it may also serve a third function, that is of radially limiting the omnidirectional freedom of movement of the driving element.

Finally, this retaining part, which ensures a particularly reliable functioning of the assembly, is preferably adapted to be mounted in the assembly by simple axial engagement, and is therefore very economical to use.

In order that the invention may be more fully understood, embodiments in accordance therewith will now be described by way of example and with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a half-view in axial section of a clutch release bearing according to one embodiment of the invention, taken on the line I I in Fig. 1; Figure 2 is a half-view thereof in elevation, taken in the direction of the arrow II in Fig. 1; Figure 3 is.another half-view thereof in axial section taken on the line Ill-Ill in Fig. 2; Figure 4 is a partial plan view thereof looking in the direction of the arrow IV in Fig.

2; Figure 5 is a partial half-view in elevation similar to that of Fig. 2 but showing a modified embodiment; Figure 6 is a partial view in section of this modified embodiment, taken on the line VI-VI in Fig. 5; Figure 7 is a view similar to that of Fig. 6, but showing another modified embodiment; Figure 8 is a half-view in axial section similar to that of Fig. 1 and showing another modified embodiment, taken along the line VIII-VIII in Fig. 9; Figure 9 is a partial half-view in elevation of this modified embodiment, looking in the direction of the arrow IX in Fig. 8; Figure 10 is a partial plan view thereof, looking in the direction of the arrow X in Fig.

9; Figure 11 is a view in axial section of another clutch release bearing, taken on the line Xl-Xl in Fig. 12; Figure 12 is a view thereof in elevation, looking in the direction of the arrow XII in Fig. 11; Figure 13 is a view thereof, partly in axial section and partly in plan, taken on the broken line XI I I-XI I I in Fig. 12; Figure 14 is a half-view thereof in axial section, taken along the line XIV-XIV in Fig.

12; Figure 15 shows again, on a larger scale, a detail of Fig. 14 marked by a box XV in that Figure; Figures 16 and 1 7 are views respectively similar to those of Figs. 11 and 1 3 but illustrating a modified embodiment; Figure 18 is a view similar to that of Fig.

11, but showing another modified embodiment; Figure 19 is a view in axial section of another clutch release bearing, taken on the line XIX-XIX in Fig. 20; Figure 20 is a view thereof in elevation in the direction of the arrow XX in Fig. 19; Figure 21 is a view in axial section corresponding to that in Fig. 19, showing separately only the operating member used in this clutch release bearing; Figure 22 is another half-view in axial section of this operating member, taken along the line XXII-XXII in Fig. 21; Figure 23 shows again, on a larger scale, a detail of Fig. 21 marked by a box XXIII in that Figure; Figure 24 is a view in axial section, taken on the broken line XXIV-XXIV in Fig. 25, of the retaining part used in the clutch release bearing of Fig. 19, this part being shown separately;; Figure 25 is a view in elevation of this retaining part, in the direction of the arrow XXV in Fig. 24; Figure 26 is a partial view thereof in the direction of the arrow XXVI in Fig. 25; Figure 27 is a similar view to that in Fig.

24 but shows a modified embodiment; Figures 28 and 29 are views respectively similar to those in Figs. 1 9 and 20 illustrating a modified embodiment; Figure 30 is a view in axial section of this modified embodiment, taken along the line XXX-XXX in Fig. 29; Figure 31 is a view similar to that in Fig.

29 but relates to another modified embodiment.

As illustrated in these drawings, a clutch release bearing comprises generally, in a manner know per se, an operating member 10 intended to be subjected to the action of a control means, which in practice is usually a clutch release fork of which one finger is partially shown schematically in broken lines in Figs. 1, 4, 7 and 8 to 10 and which hereafter will be given the general reference 11, and a driving element 1 2 intended to act directly on the release means of a clutch (not shown) under the action of the operating member 10.

The operating member 10 is made of synthetic material and comprises an axially disposed sleeve 1 3 and a transversely disposed flange 14, the sleeve 1 3 and flange 1 4 being integral with one another.

In the examples illustrated this flange 14 is generally annular and on its outer periphery is provided with a collar 1 5 on the side facing the driving element 12.

For supporting the control means 11, a metal support element 1 7 is disposed axially between the driving element 1 2 and the flange 14 of the operating member, this flange 14 being provided locally, in diametrically opposite positions and in accordance with arrangements described in detail later on, with two passages 1 8 providing access to the support element 1 7 for the two fingers of the control means 11.

In the examples illustrated, the support element 1 7 lies against the flange 14 of the operating member 10 and thus acts as a lining for the flange in relation to its thickness.

However, this is not always the case.

In any event, this support element 1 7 is a simple flat or substantially flat washer, resulting solely-from a cutting-out operation from a metal blank, without any working or shaping of this blank.

The metal blank may therefore advantage dusly be one which has already undergone heat treatment or other hardening treatment.

In the embodiments illustrated in Figs. 1 to 27, the internal and external contours of the washer forming the supporting element 1 7 are both entirely circular, but this again is not dbligatory, since either or both of these contours could, for example, be provided at least locally with one or more flats or radial enlargements, as will be described in connection with Figs. 28 to 31, or could more generally be of any shape.

In the examples illustrated in Figs. 1 to 10, the washer forming the support element is 1 7 is centred by its outer periphery on the axial collar 1 5 of the flange 14 of the operating member 10, but this is likewise not obligatory since on the contrary its centering could for example be achieved by means of its inner periphery on the sleeve 1 3 of the operating member, as will be shown later on, or on any other bearing surfacc whether circularly continuous or not---of that member.

In the examples illustrated, the driving element 1 2 comprises a ball bearing of which the outer ring 20, and only this outer ring, bears axially against the support element 17, while the inner ring 21 is free of all contact with this support element 1 7 and forms the operative part of this driving element 12, that is to say the part intended to act on the release means of a clutch.

In the practical case of a self-centering clutch release bearing, the driving element 1 2 is free to move radially in any direction in relation to the axis of the assembly, in contact with the support element 1 7 and within the limits of the radial movement permitted by the axial collar 1 5 of the flange 14.

In order to complete the clutch release bearing, connection means are provided which axially fasten the driving element 1 2 to the operating member 1 0.

In the examples illustrated, these connection means comprise a connecting cover 23 which, as described in detail in the French Patent Application No. 75 40052 published under No. 2,337,281, comprises a plurality of axial lugs 24, of which there are four in the embodiments illustrated in Figs. 1 to 7 and three in that illustrated in Figs. 8 to 10, and a front wall 25.

By means of its axial lugs 24, this connecting cover 23 is connected to the operating member 10, each of these axial lugs 24 having an opening 26 by which it is engaged on a hook 28 formed at the end of a finger 29 which axially extends the axial collar 1 5 of the flange 14 of the operating member 10.

With its front wall 25, which forms elastic means having an axial action, comprising for example a corrugated washer of the "ONDU FLEX" type as illustrated, the connecting cover 23 bears against the driving element 12, or more precisely against the outer ring 20 thereof, and thus urges the outer ring 20 against the support element 17, as mentioned previously.

This elastic force has the consequence that the desired self-centering is maintained, the driving element 1 2 retaining its position in relation to the axis of the assembly when it is not subjected to any radial stress; the material of which the washer 50 is made is selected accordingly.

For guiding of the control means 11, each passage 1 8 of the flange 1 4 is preferably provided at its edge with an axial lug along at least part of at least one of its edges.

In the embodiment illustrated in Figs. 1 to 4, the passage 1 8 forms a cutout, opening onto the outer periphery of the flange 14, being bounded on the one hand, on its inner periphery, by a main edge 30 parallel to the axial plane of symmetry P of the assembly indicated schematically in broken lines by its outline in Fig. 2 and on the other hand by two side edges 31, both of which extend along a chord as far as the outer periphery of the flange 14, perpendicularly to the axial plane of symmetry P.

In this embodiment the axial lug 32 extends along the main edge 30 for the purpose of guiding the control means 11, and this axial lug 32 thus extends substantially tangentially to the inner periphery of the flange 14, parallel to the axial plane of symmetry P.

In practice this axial lug 32 is provided, at the end of an extension 33, with a rightangled return 34, which is spaced from and extends parallel to the flange 14, above the base of the corresponding passage 1 8 in this flange 14.

In the case of a clutch release bearing intended to be held permanently against the release means of a clutch, a return 34 of this kind is sufficient to secure it to the control means 11, in a manner known per se, during operation of the assembly.

In operation, each of the fingers of the-control means 11 bears against the corresponding outer flank of the axial lug 32, and this is sufficient to achieve correct guidance of the control means when it is articulated to a simple swivel joint.

In order to avoid interference, during operation, with the control means 11, at least one (and in practice both) of the side edges 31 of each of the passages 1 8 in which the fingers of this control means 11 are engaged, is formed with a chamfer 35, as illustrated.

In the modified embodiment illustrated in Figs. 5 and 6, each passage 1 8 of the flange 14 forms an enclosed opening in this flange, and the axial lug 32 provided for guiding the control means 11 borders that one of the main edges 30 of the opening which is radially the most distant from the axis of the assembly.

The axial lug 32 thus extends in this case substantially tangentially to the outer periphery of the flange 14, parallel to the axial plane of symmetry P of the assembly.

In practice, in the embodiment illustrated, each passage 1 8 in the flange 14 is bordered by an axial lug not only along at least a psrt of one of its main edges 30, but also along at least a part of one of its side edges 31. In practice this side edge 31 is the one situated on the side where the ends of the fingers of the control means 11 lie.

Thus in this embodiment, each passage 1 8 of the flange 1 4 is bordered by an axial lug along at least part of at least two of its contiguous edges.

For the side edge 31 in question the corresponding axial lug bears the reference 37 in the drawings, and it extends along a chord of the flange 1 4 perpendicularly to the axial plane of symmetry P.

In the example illustrated in the drawings, a connecting wall 38 continuously connects this axial lug 37 to the right-angled return 34 of the axial lug 32 bordering the contiguous main edge 30.

This results in the advantageous stiffening of the assembly.

As previously, in the embodiment illustrated in Figs. 5 and 6 the guiding of the control means 11 in operation is effected by the axial lug 32 bordering the main edge 30 of the passages 18, this guidance being achieved in this case by the inner flange of lug 32.

As an alternative (Fig. 7), this guidance can be achieved at the ends of the fingers of the control means 11, solely by the axial lug 37 which borders one of the side edges 31 of the passages 18.

In this case the lug in question may be reduced in size.

In addition, the right-angled return 39 which it carries for attachment to the control means 11 can in this case be engaged between the flanks of the corresponding finger of the control means 11, when as illustrated and as is usual, this finger has a concave profile.

In the embodiment illustrated in Figs. 8 to 10, the axial lug 32 intended for guiding the control means 11 extends, as in the case of the embodiment illustrated in Figs. 1 to 4, substantially tangentially to the inner periphery of the flange 14, and the main edge 30 of the corresponding passage 1 8 extends, at one or both of its ends, as far as the outer periphery of the flange 14.

In the embodiment illustrated, the main edge 30 extends in this way to the outer periphery of the flange 14 only at one of its ends, while the corresponding passage 1 8 in flange 14 is bounded on the one hand by a main edge 30 and on the other hand by a side edge 31, with the exception of the remaining portion of the axial lug 1 5 of the flange 14.

In addition, in this embodiment, in the case of a clutch release bearing which is not intended to be held permanently in contact with the clutch release means, a pin 40 is associated with each passage 1 8 for the purpose of connecting the clutch release bearing to the control means 11, this pin 40 being in engagement with the clutch release bearing and being adapted to be engaged with the control means 11. The pin 40 is partly inserted between the support element 1 7 and the operating member 10.

In practice, the flange 1 4 of the operating member 10 has two passages 1 8 and thus two pins 40 are provided; these pins form the ends of a single part 41 whose median zone 42 forms the parts of the pins which are inserted between the operating member 10 and the support element 1 7.

In the example illustrated, this median zone 42 is generally U-shaped and extends to the inner periphery of the support element 1 7 in a semi-circular groove 43 which is formed for that purpose in the inner periphery of the transverse flange 14, and which terminates laterally at the outer periphery of the flange 1 4 in side arms 44.

Each pin 40 is formed by a U-shaped bend of the corresponding end of the part 41, and its free end is in turn shaped as a half-wave so as to bear against the corresponding finger of the control means 11.

Thus, each pin 40 extends partly on one side of the flange 14 of the operating member 10 and partly on the other side thereof, and it is engaged on the flange 1 4 by simple elastic deformation.

In the embodiments illustrated in Figs. 11 to 18, the clutch release bearing comprises, as previously, an operating member 10 which is intended to be subjected to the action of a control means (not shown), which in practice is a clutch release fork, and a driving element 1 2 which is intended to act on the release means of a clutch (likewise not shown) under the action of the operating member 1 0.

The operating member 10, which is made of synthetic material, comprises a unitary part consisting axially of a sleeve 1 3 and, transversely, a flange 14.

In the embodiment illustrated, the flange 1 4 is generally annular and on its outer periphery, on the side where the driving element 1 2 is situated, is formed with an axial collar 1 5.

As with the previous embodiments, a sup port element 1 7 comprising a simple metal washer is disposed axially between the driving element 1 2 and the flange 14 of the operating member 10, with the interposition of a washer 50 in the example illustrated.

In order to provide access to this support element 1 7 for the control means, the flange 14 of the operating member 10 is provided locally in symmetrically opposite positions with two passage 18, each of which is bordered on the one hand by an axial flat 51 on the sleeve 1 3 of the operating member 10, for the purpose of guiding the control means, and on the other by a lug 52 for axially retaining the release bearing with respect to the control means.

In the embodiment illustrated, and as previously described, the driving element 1 2 consists of a ball bearing of which the outer ring 20, and only this outer ring, bears axially against the support element 17 through the washer 50 and, through the support element 17, against the flange 14 of the operating member 10, while its inner ring 21 is free of all contact with any other component of the clutch release bearing and forms the operative part of the driving element 12, that is to say that part of the driving element which is intended to act on the clutch release means.

Where in practice the clutch release bearing is of the self-centering type, the driving element 1 2 is free to move radially in any direction in relation to the axis of the assembly, in contact with the washer 50 and within the limits of radial movement permitted by the axial collar 1 5 of the flange 1 4 and/or the sleeve 13.

In other words, the driving element 1 2 has radially, within the limits in question, an omnidirectional latitude of movement in relation to the axis of the assembly.

As previously described, connection means axially fasten the driving element .12 to the operating member 10, these means consisting of a connecting cover 23 comprising a plurality of axial lugs 24, of which there are four in the example illustrated, and a front wall 25.

By means of its axial lugs 24 this connecting cover 23 is fastened to hooks 28 on the operating member 10, and by its front wall 25, which forms an axially-acting elastic washer of the "ONDUFLEX" type, urges the driving element 1 2 in the direction of the flange 1 4 and therefore holds the driving element 1 2 in contact with the washer 50, which itself is held in contact with the support element 1 7.

As previously, therefore, the clutch release bearing is one of the self-centering type which is maintained during subsequent operation.

On the opposite side of the flange 14 to the driving element 12, axial retention of the support element 1 7 is effected positively by the flange 14.

According to this embodiment of the invention axial retention means are also associated with the support element 1 7 on that side of the flange 14 which faces the driving element 12, so that this axial retention is effected positively in both directions.

In the embodiment illustrated in Figs. 11 to 15, these axial retention means comprise at least two lugs 54 disposed radially on the outer periphery of the washer forming the support element 17, and for each of these lugs 54 there is provided on the axial collar 1 5 at a distance from the flange 14, a transverse shoulder 55 which faces axially towards this flange 14 and with which one such lug 54 is in contact.

In practice, for each axial lug 54 of the support element 1 7 there is formed in the axial collar 1 5 of the flange 14 of the operating member 10 a recess 56 level with this flange 1 4, and the transverse shoulder 55 provided on the axial collar 1 5 is at least partly formed directly by the actual edge of this axial collar 1 5.

In the embodiment illustrated, a recess 56 is formed not only in the axial collar 1 5 but also extends into flange 14, so that it leads out axially on the opposite side to the driving element 1 2. Three axial lugs 54 are provided on the support element 1 7.

Two of these are formed at right angles to the passages 1 8 in the flange 14, so that the recesses 56 provided for these lugs 54 are themselves formed at right angles to these passages 1 8 and lead out radially into the passages.

A specific recess 56 is provided for the third lug 54 of the support element 1 7.

As can easily be understood, the positioning of the washer constituting the support element 1 7 entails clipping of the washer in place, the washer being engaged axially in the space formed between the sleeve 1 3 and the axial collar 15, these lugs 54 producing transverse local elastic deformation of the axial collar 1 5 until they reach positions at right angles to the recesses 56 and engage behind the edge of the axial collar 1 5.

The washer constituting the support element 1 7 is then retained axially in a positive manner, on one side by bearing against the flange 14 and on the other side, by the bearing of these lugs 54 against the edge of the axial collar 1 5 of the flange 14.

In the embodiments illustrated in Figs. 1 5 to 1 8, the axial retaining means for the support element 1 7 on the side where the driving element 1 2 is situated comprise a web 58 which is integral with the operating member 10 and which is moulded over at least a part of the support element 1 7.

In the embodiment illustrated in Fig. 1 6 this web 58 extends over the entire support element 1 7 on the side where the driving element 1 2 is situated, so that it constitutes in itself a washer interposed between the driving element 1 2 the support element 1 7.

As an alternative, in Figs. 1 7 and 1 8 the web 58 is reduced on the one hand to a lip 58' which engages radially onto the inner periphery of the support element 17, and on the other hand to a lip 58" which in practice is made continuous with the axial collar 1 5 of the flange 1 4 of the operating member 10 and engages radially onto the outer periphery of this support element, the driving element 1 2 being situated directly in contact therewith.

In the embodiment illustrated in Figs. 1 9 to 26 the clutch release bearing comprises gen erally, and as in the previous cases, an operat ing member 1 0, and a driving element 1 2.

The operating member 10, which is of synthetic material, comprises a unitary assem bly consisting axially of a sleeve 1 3 and flange 1 4 located approximately half-way along the length of the sleeve 1 3 in the embodiment illustrated. The flange 14 has a collar 15, and a metal support element 17, bears axially against the flange 14 on that side of the flange which faces the driving element 1 2.

As previously, this support element 1 7 con sists of a simple washer disposed transversely in relation to the axis of the assembly; in the embodiment illustrated this washer is centered by its inner periphery on the sleeve 1 3. In order to allow the control means access to the support element 17, the flange 1 4 of the operating member 10 is provided symmetri cally in relation to an axial plane of the assembly with two passages 1 8 (Figs. 20 and 22).

Level with the sleeve 13, each of the pas sages 1 8 is bordered locally by a boss 60 which, with the aid of a flat 51 parallel to the axis of symmetry of the assembly, is adapted to guide the control means (Fig. 20).

Perpendicularly to one such flat 51 each passage is in addition bordered locally by a bracket 52, which projects axially, extending locally above the passage, and is adapted to retain the release bearing axially relative to the control means.

At various points radial ribs 61 are formed between the sleeve 1 3 and the flange 14; these ribs extend as far as the outer periphery of the flange 1 4 or stop some way short of this periphery when their direction intersects the passages 18 in the flange 14.

According to this embodiment of the inven tion, for the axial retention of the support element 1 7 on the side where the driving element 1 2 is situated, there is associated with the support element 1 7 an annular re taining part 62 which bears axially against the operating member 10 and holds the support element 1 7 in contact with the flange 1 4 of the operating member 10. In the embodiment illustrated this annular retaining part 62 is of synthetic material; as an alternative, however, it may also be of metal, for example spring steel.

In the embodiment illustrated, part 62 comprises a washer 63 interposed axially between the driving element 1 2 and the support element 17.

In this embodiment it also comprises a crown 64 which is elongated axially and bears axially at its free end against a transverse shoulder 65 of the operating member 1 0.

In practice, the crown 64 of the annular retaining part 62 is provided at its free end with an annular lip 66 projecting radially outwards in order to bear on the transverse shoulder 65 of the operating member 10 with adequate annular support. This crown 64 is circularly fragmented by axial slits 68 to form tongues 67 over at least part of its length, starting from its free ends. These axial slits 68 extend as far as the washer 63 over the entire length of the crown 64.

In the embodiment illustrated, the transverse shoulder 65 of the operating member 10 is formed, at the end of the axial collar 15, on a bead 70 projecting radially inwards.

This bead 70 is reduced to a plurality of isolated segments 71, of which there are three in this embodiment, and which are distributed circularly around the axis of the assembly.

Two of these segments 71 are each respectively disposed axially at right angles to the passages 1 8 in the flange 14, while the third is disposed axially at right angles to a recess 72 provided in the flange 1 4. During the moulding of the operating member 10 the passages 1 8 and the recess 72 in the flange 1 4 permit the intervention of punches suitable for the moulding of the segments 71 forming the bead 70.

As previously, the driving element 1 2 is composed of a ball bearing, whose outer ring 20, and only this outer ring, bears axially against the washer 63 of the annular retaining part 62 and, through this washer 63 and the support element 1 7, against the flange 14 of the operating member 10, while its inner ring 21 is free of all contact with any other part and is intended to act on the clutch release means.

Likewise as previously, a connecting cover 23, having axial lugs 24 and a corrugated front wall 25, connects the driving element 1 2 to the operating member 10, each of these axial lugs 24 being engaged on a hook 28 on the axial collar 1 5 of the operating member 1 0.

As will be noted, the various components of the clutch release bearing thus constituted are assembled very simply by axially stacking the component parts on one and the same side of the flange 1 4 of the operating member -10.

In particular, the annular retaining part 62 is very simply engaged axially in the space defined by the axial collar 1 5.

For preference, and as illustrated, this axial engagement is facilitated by the fact that at its free end this axial collar 1 5 is provided with a chamfer 75 on its radially innermost edge.

As will be understood, when the annular retaining part 62 is thus engaged axially the tongues 67 formed by the crown of the part 62 are deformed elastically in the direction of the interior on passing the segments 71 forming the bead 70 of the operating member 10, and after passing the transverse shoulder 65 of this bead, return to their original shape so as to bear axially against this transverse shoulder 65.

The axial length of these tongues 67 is obviously determined in such a manner that on the one hand they have adequate elasticity for this deformation, and on the other hand they are able to withstand appropriately the axial buckling forces to which they may be subjected through the thrust of the control means, and the axial length of the axial collar 1 5 of the flange 14 of the operating member 10 is determined accordingly.

In the modified embodiment illustrated in Fig. 27, one of the tongues 67-the one which is situated in the bottom part of the Figure is axially longer than the others and is thus adapted to cooperate as a circumferential stop with one of the circumferential ends of the corresponding segment 71 of the operating member 10, in order to lock the annular retaining part 62 on the latter against rotation which might occur during self-centering.

This arrangement prevents the washer forming the support element 1 7 from being rotated, and therefore permits a reduction of wear and/or avoids interference with the general conditions of friction controlling any possible movement of the driving element 1 2.

However, this is not an indispensable arrangement.

On the contrary, in certain cases and for certain applications, and particularly in dependence on the nature of the materials used, rotation of the washer constituting the support element may be permitted during self-centering for the purpose of evenly distributing wear caused by contact with the associated control means.

In all cases, if it is desired that the friction controlling the maintained self-centering action of the driving element should result from metal-to-metal contact, the annular retaining part according to the invention may be reduced to its crown 64 alone, it being understood that the axial slits- 68 provided in the crown will then extend only over a part of its axial length.

Thus, depending on the particular conditions of application, the present invention readily lends itself to varying the coefficients of friction for the maintained self-centering action which must be achieved with a selfcentering clutch release bearing.

It should moreover be noted that when, for obtaining a coefficient of friction of this kind, the annular retaining part according to the invention comprises a transverse washer 63, the radial extension of the latter can advantageously be reduced to the value strictly necessary for the desired contact with the driving element 1 2, thus minimising the amount of material necessary for making this annular retaining part.

In this case, this part may moreover be reduced to its washer 63, the centering of this washer 63 then being effected by the axial collar 1 5 of the flange 14, while axially the washer bears directly against the transverse shoulder 65 of the operating element 10, this shoulder being brought closer for the purpose, on the opposite side to the flange 1 4.

In the modified embodiments illustrated in Figs. 28 to 31, the washer forming the support element 1 7 comprises radially, in positions diametrically opposite one another, projections 77, which are adapted to widen the seating of the associated control means, these projections being formed with the aid of the passages 1 8 in the flange 14 of the operating member 10, and with the help of a local interruption of the axial collar 1 5.

In the embodiments illustrated, these projections 77, each of which has a generally quadrangular contour, extend beyond the periphery of the flange 14 of the operating member 10.

An arrangement of this kind makes it possible to have a wider opening for the control means, and in certain cases overcomes other obstacles which might otherwise hinder its operation.

Otherwise, the embodiments illustrated in Figs. 28 to 31 are similar to that described with reference to Figs. 1 9 to 26, with the following differences in respect of details: in order not to interfere with the projections 77 of the support element 17, the axial lugs 24 of the connecting cover 23 and the hooks 28 of the operating member 10 are offset circum ferentially in relation to these projections 77; the passages 1 8 in the flange 14 have a reduced extension, which is limited to the width of the projections 77; in the flange 14 there is a recess 72 for each of the segments 71; and the sleeve 1 3 is grooved internally and this sleeve 1 3 extends only on that side of the flange 1 4 which is opposite the driving element 12, while on the other side of the flange 14 the sleeve 1 3 is reduced to the two bosses 60 having a guide flat 51 edging the passages 18.

In the embodiment shown in Figs. 28 to 30 the brackets 62 intended for axially retaining the clutch release bearing in relation to the associated control means extend parallel to the corresponding guide flats, as in the embodiments shown in Figs. 11 to 26.

As an alternative (Fig. 31) they extend perpendicularly to these guide flats 51, starting from the latter; in such a case these brackets 52 may if desired be brought axially closer to the support element 1 7 through the presence of corresponding slots in the associated control means, in order to reduce the axial dimension of the assembly and therefore to obtain a more compact and less fragile arrangement.

The present invention is not limited to the embodiments described and illustrated, but includes any modified embodiment and/or combination of their various elements within the scope of the appended claims.

In particular, while in the embodiments described above the washer constituting the support element 1 7 is strictly flat, this is not necessarily always the case.

On the contrary, and as indicated schematically in broken lines in Fig. 6, it may be provided locally with one or more bosses extending axially into the corresponding passages in the flange of the operating member, in order to lock it on the latter against rotation, when for the reasons explained above this rotational locking is desired, and/or for the support of the control means.

Furthermore, although in the foregoing it is the inner race of the ball bearing forming the driving element that constitutes the rotating part thereof, as an alternative this rotating part could be formed by the outer race.

The field of application of the invention is not moreover limited to that of self-centering clutch release bearings, but extends more generally to any type of thrust bearing.

In all cases it will be appreciated that the invention advantageously enables the use of a standard plate or washer to form the support element, while, through the axial length of the ball bearing forming the driving element and/ or the thickness of optionally overmoulded material or that of the washer of the retaining part which is optionally used, control appropriate to each case of the axial distance separating the support element from the free end of the driving element is thus obtained.

Claims

1. A clutch release bearing comprising an operating member made from synthetic material, which operating member is intended to be acted on by a control means such as a clutch release fork, and which is provided with a transverse flange, a metal support element adapted to support the control means, a driving element adapted to act on clutch release means, and connection means axially connecting the driving element to the operating member, the support element comprising a simple, substantially flat washer disposed axially'between the driving element and the flange of the operating member, and the flange being provided locally with passages allowing the control means access to the support element.

2. A clutch release bearing according to Claim 1, wherein each passage in the flange of the operating member is bordered by an axial lug extending along at least part of at least one of its edges for guiding the control means.

3. A clutch release bearing according to Claim 2, wherein said axial lug extends substantially tangentially to the inner periphery of the flange, parallel to the axial plane of symmetry of the assembly.

4. A clutch release bearing according to Claim 3, wherein at one or both of its ends, the said edge provided vvith the axial lug extends as far as the outer periphery of the flange.

5. A clutch release bearing according to Claim 2, wherein the axial lug extends sub stantially tangentially to the outer periphery of the flange, parallel to the axial plane of symmetry of the assembly.

6. A clutch release bearing according to Claim 2, wherein the axial lug extends along a chord of the flange, perpendicularly to the axial plane of symmetry of the assembly.

7. A clutch release bearing according to any of Claims 3 to 6, wherein the axial lug is provided with a right-angled return parallel to the flange and spaced therefrom for connection to the control means.

8. A clutch release bearing according to any of Claims 3 to 6, wherein each passage in the flange is bordered by an axial lug along at least part of at least two of its contiguous edges.

9. A clutch release bearing according to a combination of Claims 7 and 8, wherein a connecting wall continuously connects one of the axial edges to the right-angled return of the other.

1 0. A clutch release bearing according to any of Claims 1 to 6, wherein for connection to the control means, a pin is associated with each passage in the flange of the operating member, which pin is in engagement with the clutch release bearing and is adapted to be engaged on the control means, and is partly inserted between the support element and the operating member.

11. A clutch release bearing according to Claim 10, wherein the part of the pin which is inserted between the support element and the operating member extends to the inner periphery of the support element.

1 2. A clutch release bearing according to Claim 10 or Claim 11, wherein the flange of the operating member has two passages and the pins associated with them form the ends of one and the same part whose median zone is inserted between the operating member and the support element.

1 3. A clutch release bearing according to any of Claims 1 to 12, wherein at least one of the edges of each passage in the flange of the operating member which are perpendicular to the axial plane of symmetry of the assembly is formed with a chamfer.

14. A clutch release bearing according to any of Claims 1 to 13, wherein the support element is provided locally wittat;.least one boss which extends axially intoa corresponding passage in the flange of th,e.operating member.

1 5. A clutch release bearing according to any of Claims 1 to 14, wherein the support element is provided locally with at least one radial projection.

1 6. A clutch release bearing according to Claim 1, wherein axial retention means are associated with the support element on that side of the flange of the operating member facing the driving element, and the flange of the operating member is provided on.its outer periphery with an axial collar, and the retention means comprise at least two lugs disposed radially on the outer periphery of the the washer forming the support element, and for each of said lugs of the support element there is provided on the axial collar of the flange of the operating member, and spaced therefrom, a transverse shoulder which faces axially towards the flange and which is in contact with one such lug.

1 7. A clutch release bearing according to Claim 16, wherein a recess is formed in the axial collar of the flange of the operating member level with the flange, and the transverse shoulder formed on said axial collar is formed at least partly by the actual edge of said axial collar.

1 8. A clutch release bearing according to Claim 17, wherein the recess in the axial collar of the flange also extends into the flange and leads out axially on the opposite side to the driving element.

1 9. A clutch release bearing according to any of Claims 1 6 to 1 8, wherein three lugs are provided on the support element.

20. A clutch release bearing according to a combination of Claims 17, 18 and 19, wherein two of the recesses in said axial collar are disposed at right angles to the passages formed in the flange, and lead out radially into these passages.

21. A clutch release bearing according to Claim 1, wherein axial retaining means are associated with the support element on that side of the flange of the operating member which faces towards the driving element, and these retaining means comprise a web integral with the operating mem-ber and moulded over at least a part of the support element.

22. A clutch release bearing according to Claim 21, wherein said web extends over the entire support element.

23. A clutch release bearing according to Claim 21, wherein the web is reduced to a lip along the inner and/or outer periphery of the support element.

24. A clutch -release bearing according to Claim 1, wherein for axially retaining the support element on the driving element side, the annular retaining part is associated with the support element which part bears axially against the operating member and holds the support element in contact with the flange of the operating member.

25. A clutch release bearing according to Claim 24, wherein the retaining part incorporates a washer which is interposed axially between the driving element and the support element.

26. A clutch release bearing according to Claim 25, wherein the retaining part comprises a washer.

27. A clutch release bearing according to Claim 24, wherein the retaining part incorporates an axially elongated crown.

28. A clutch release bearing according to Claim 27, wherein the retaining part comprises a crown.

29. A clutch release bearing according to either Claim 27 or Claim 28, wherein the crown provided in the retaining part for the support element has an annular lip which projects radially outwards.

30. A clutch release bearing according to any of Claims 27 to 29, wherein over at least part of its length, said crown is circularly divided from its free end into tongues by means of axial slits.

31. A clutch release bearing according to a combination of Claims 25 and 30, wherein the axial slits extend up to the associated washer.

32. A clutch release bearing according to Claim 30 or Claim 31, wherein one of said tongues is axially longer than the others.

33. A clutch release bearing according to any of Claims 24 to 32, wherein on the opposite side to the flange of the operating member, the retaining part for the support element bears axially against a transverse shoulder on the operating member.

34. A clutch release bearing according to Claim 33, wherein the transverse shoulder on the operating member is formed at the end of an axial lip, on a bead projecting radially inwards and provided annularly on the operating member.

35. A clutch release bearing according to Claim 34, wherein the bead of the operating member is reduced to a plurality of circularly distributed segments.

36. A clutch release bearing according to a combination of Claims 32 and 35, wherein said longer tongue forms a circumferential stop which co-operates with one of the circumferential ends of a corresponding segment in order to lock the retaining part against rotation.

37. A clutch release bearing according to any of Claims 34 to 36, wherein, at its free end, the axial lip of the operating member is formed with a chamfer on its radially innermost edge.

38. A clutch release bearing, substantially as hereinbefore described with reference to Figs. 1 to 31 of the accompanying drawings.