FR2723995A1 - Auto centring clutch thrust bearing - Google Patents

Abstract

The clutch thrust bearing consists of a drive (13) forming a sleeve (12) and a tube (15) respectively fixed in rotation with the fixed (34) and turning (32) parts of a bearing (30). The fixed part of the bearing is held by friction between the two radial faces of the support of the sleeve under the action of an elastic wavy washer (45). This wavy washer (25) is incorporated in the fixed part of the bearing.

Description

"Self-centering clutch release bearing
The present invention relates to a declutching stop, in particular for a motor vehicle, of the kind comprising an element for free operation in translation along an axis under the action of an operating member such as a declutching fork or the piston of a hydraulic control, a driving element intended to act on the disengaging device of a clutch, such as a diaphragm or disengaging levers, and, between the driving element and the operating element, a connection d self-centering active in translation and having, in a plane perpendicular to the axis, a path latitude controlled by friction tightening, so that if during assembly the axis of the stopper and the axis of the clutch does not are not exactly confused the element of attack places itself and remains exactly centered with respect to the axis of the clutch.

 Such a stop, known as self-centering, is described in documents FR-A-1 467 848 and FR-A-2 513 337.

 In document FR-A-1 467 848 the stop is intended to act in thrust on the clutch disengaging device, while in document FR-A-2 513 337 it acts in traction on said disengaging device.

 In these two documents, the self-centering link comprises an elastic washer with axial action and an annular rim belonging to the operating element, the elastic self-centering washer resting on a shoulder carried by said rim as described in the document FR- A-1 467 848 or on a flange of the operating element as described in document FR-A-2 513 337.

 Thus during the declutching operation the self-centering washer is not stressed.

However, as described, for example in the document
FR-A-92 993, this washer can also be stressed.

As described in the latter document, the self-centering link may include a cover crimped onto a flange of the operating element. A cover can also be attached by clipping onto the operating element, as described for example in EP-A-0 382 778 and FR-A-2 508 125.

 In all cases, the operating element and the attack element are respectively associated with the fixed and rotating parts of a bearing which, for its part, constitutes an essential component of the stop, allowing the freedom of rotation of the attack element with respect to to the operating element.

 Furthermore, the self-centering elastic washer is an independent part requiring precise positioning during mounting of the stop. This is a source of complications in the problems of mounting the self-centering stops: an illustration of this source of difficulties can be found, for example, in document FR-A-2 670 854 dealing with special provisions to avoid any risk of jamming during assembly and deterioration of the self - centering washer.

 The object of the present invention is to overcome all such disadvantages and difficulties in a simple and economical manner.

 To this end, it proposes a self-centering declutching stop of the type considered, essentially characterized by incorporating the elastic self-centering washer into the structure of the non-rotating part of the bearing of the stop.

 Thanks to this arrangement, the bearing and the self-centering washer will form a one-piece assembly which can be manipulated, transported and lost, the number of parts of the stop being reduced accordingly to the benefit of costs.

 In addition, during the final assembly there is no risk of making the wrong washer since it is integrated into the associated bearing.

 The calibration of the self-centering will thus be perfect, said calibration varying according to the applications.

 Note that the number of pieces to be stored is reduced.

 In addition, the final assembly is facilitated and there is no risk of jamming the self-centering washer.

 The number of discarded parts is reduced.

 During the final assembly phase, the tools are also simplified, as well as the assembly times.

The characteristics and advantages of the invention will become apparent from the description which follows, by way of example, with reference to the accompanying drawings in which
- Figure 1 is a schematic half-view in axial section of a self-centering clutch release bearing arranged according to the invention;
- Figure 2 is a plan view of a rolling element according to the invention;
- Figure 3 is a sectional view along line III
III of figure 2
- Figure 4 is a view similar to that of Figure 1 relating to another embodiment
- Figure 5 is a plan view of the rolling element fitted to this embodiment
- Figure 6 is a section along line VI-VI of Figure 5.

 - Figure 7 is a view similar to that of Figure 4 in case of reversal of the position of the self-centering elastic washer.

According to the embodiment illustrated in Figures 1 to 3, the invention is applied to a self-centering stopper 10 of known general design, described in particular in
FR-94 00182. Basically there is a sleeve 12 formed at the outer periphery of an operating member 13 adapted to slide by means of a sleeve 14 with a low coefficient of friction on a guide tube not shown. , says declutching trumpet, carried by the gearbox. The disengaging fork or piston control member of a hydraulic control, for example, has not been shown any more - under the action of which the operating member 13 will have to move axially.

 The sleeve 12 is here in one piece with a radial flange 16 of the operating member and has on its radially internal face a cylindrical surface 18 extending in axial direction between two bearing surfaces of radial orientation, at namely a rear range 20, formed on a peripheral zone 22 in excess thickness of the flange 18, and a front range 24 offered by a split ring 26 called axial retaining, itself being in abutment on a collar 28 formed for this purpose radially projecting inwards at the end of the sleeve 12.

It is inside the cylindrical housing 18 thus delimited axially by the two radial bearing surfaces 20, 24 that there is mounted in a known manner a ball bearing 30 whose rotating ring 32 - here radially inside - is coming in one piece with the drive member 15 that the operating member 13 is called to actuate by means of the bearing 30. This is in this example a clutch stopper of the type pulled in because of the tubular shape of the attack member 15 for coupling with a part (not detailed) of docking behind the fingers of a diaphragm not shown: reference may be made to the documents in particular
FR-A-2 630 174 and FR-A-2 688 840.

 In FIG. 1, the clutch release bearing 10 is shown in a centered position in which the drive member 15 is centered on the axis XX of the drive member 13, therefore of the sleeve 12. The drive member 15 being in one piece with the rotating inner ring 32 of the bearing, it is the bearing assembly, and in particular its non-rotating outer ring 34, which is centered inside the cylindrical bore 18 of the sleeve with the appropriate clearance to provide the attack member with the latitude of path allowing self-centering, path in the radial direction controlled by a friction clamping of the non-rotating ring.

 This friction tightening is carried out in a manner known per se by the axial securing means provided between the sleeve 12 and the outer ring 34 with an elastic means with axial action.

 These are the methods of making these axial securing means which are concerned with the present invention and which will now be considered in detail in what follows.

 The bearing 30 is flanked in a manner known per se by two lateral cheeks 40, 41 sometimes called "deflectors" forming means for confining lubricant, such as grease, present between the rings 34, 32 and the balls. Each of these cheeks is constituted by an annular piece of cut and stamped sheet metal to form on the radially inner side a deflector or confinement part adapted to cover the annular space limited by the two rings, and on the radially outer side a peripheral fixing part conforming to the shape of the non-rotating outer ring.

 In the case of the example considered, the fixing of the cheek 40, on the left side in the figure, is of the crimping type with folding down of a peripheral flange 42 on the external cylindrical surface of the ring 34, radially outside an annular zone 44 of contact with the corresponding lateral face of said ring 34. Unlike this arrangement, the cheek 41 has an intermediate annular part 43 stamped in a substantially axial orientation to form a fitting zone in the internal bore of the outer ring 34. Radially outside this intermediate part remains formed thus a peripheral area 45 adapted to abut in abutment against the adjacent lateral face of the non-rotating ring 34.

 According to a characteristic aspect of the present embodiment of the invention, this peripheral area 45 of the cheek washer 41 is arranged in elastic means with axial action according to the methods illustrated in FIGS. 2 and 3.

 As is more clearly visible in FIG. 2, the peripheral area has a series of radial notches 47 regularly distributed around its circumference, six in number in the example considered, each of these radial notches extending over a fraction, for example two-thirds, of the width of the range. From the bottom of each of these radial notches 47 also extends on each side in the peripheral direction, a circular notch 49 on an arc of a circle limited to an angle at the center B slightly less than the angle at the center A defined by two neighboring radial cuts. The angle A thus being 60 in the example considered, the angle B can be limited, for example to 55.

 We therefore cut out in the peripheral area 45 of the cheek washer 41 a series of tabs such as 51, 52, 53 ... each remaining attached to the remaining part of the range by a rooting area such as 50 limited to an angle at the center C = A - B, ie 5 "in the example considered.

Each peripheral tongue 51, 52, 53 ... thus cut also undergoes a wavy shaping of each of these two wings, as indicated in FIG. 3.

 A part thus configured can easily be produced from a mild steel sheet of suitable characteristics, by a cutting and stamping operation followed by a heat treatment leading to the transformation of mild steel into spring steel.

 Returning to FIG. 1, it will be seen that, according to the present invention, thus constituted an elastic means adapted to intervene in the friction tightening of the non-rotating ring 34 of the bearing 30 between the two bearing faces offered for this purpose by the sleeve 12 of the operating member 13. This elastic means is constituted here by the wavy tongues 51, 52, 53 ... distributed over the periphery of the cheek washer 41 incorporated in the overall structure of the bearing 30.

 The bearing face intended to cooperate with the elastic axial action means thus formed is the so-called rear bearing 20 offered for this purpose by the peripheral zone in excess thickness of the flange 18, while the opposite bearing face constituted by the bearing front 24 offered by the split ring 26 cooperates here with the annular contact zone 44 of the cheek washer 40.

 It is naturally possible to interpose, if necessary, a washer made of friction material, which could then advantageously be pre-assembled on the radially internal and axially projecting part of the cheek washer 40.

 I1 is also possible to envisage the realization in elastic means of the peripheral zone of the cheek washer 40 situated on the side of the split ring 26. Nothing is moreover opposed to the formation of wavy tongues cut from parts an annular area such as 44 lying between two axially projecting zones on either side, like the zones marked 40 and 42 respectively in FIG. 1.

 Figure 4 shows an example of application of the invention to a self-centering stop for clutch of the pushed type, recognizable by the shape of its attack member 60 adapted to act by pushing on the fingers of a diaphragm (not shown) clutch or the like. This stop is of the type described in document FR-A-92 933 to which reference may be made for more details and comprises two cheek washers 80, 81, like the stop in FIG. 7. Thus the attack member is here again constituted by an extension of the inner ring of a bearing 70, the non-rotating outer ring 71 of which is here again equipped with cheek washers 80,81 respectively similar to the cheek washers 40,41 of the previous embodiment.

 The operating member here comprises a radial flange 61 secured by welding with a sliding bush 62 and carrying a cover 63 serving as a housing for the bearing 70 and fixed by crimping 64 to the periphery of the flange 61. Elements of a member control, of the declutching fork type, appear diagrammatically at 65. The end wall 66 of radial orientation of the cover 63 serves as a support in its peripheral zone located opposite the outer ring 71 of the bearing to a friction washer 67 adapted to receive the support with elastic clamping of the cheek washer 80.

The elastic clamping action is again performed here with the use of elastic means incorporated in the washer 81, but according to the methods illustrated in FIGS. 5 and 6.

 Here, around the radially internal part 81 serving as a deflector, there is an axial orientation part 83 adapted to fit at the entrance to the bore of the outer ring 71 of the bearing, and a peripheral zone 85 enveloping on a fraction of its radial extent the lateral face of the ring 71, while on the remainder of its radial extent, it is cut into a plurality of tabs 87 of trapezoidal shape, succeeding each other with a slight gap between them over the entire periphery and being inclined towards the axis of the bearing by an appropriate angle which may be of the order of 30 for example. Advantageously, moreover, these tongues 87 form an acute angle with a plane perpendicular to the axis of the stop.

 The cheek washer thus formed by cutting, stamping and heat treatment will again be able to constitute, after incorporation into the structure of the bearing 70 (FIG. 4), an elastic means inserting without any problem of centering in a self-centering device maintained with a calibration capable of being determined in particular by the choice of the friction and support washer such as 67.

 Note also that in the embodiment of Figure 1, the elastic means 50 is not stressed in the application of the declutching force, while it is the opposite in the case of the example of Figure 4 where the elastic means 87 is interposed in the line of application of forces from the control piece 65 to the attack piece 60.

The choice between these two situations remains entirely free depending on the wishes to be taken into account in each application case.

 Thus, in the case illustrated in FIG. 7, the position of the fitted cheek washer 81 has been reversed with that of the conventional cheek washer 80.

 Furthermore, the rotating part of the bearing carrying or constituting the attack piece could of course be situated on the radially outer side, in which case the elastic means, constituting according to the present invention the self-centering washer, will be formed on a radially peripheral zone inside of the corresponding cheek washer.

Claims (5)

 1. Self-centering clutch release bearing, in particular for motor vehicles, of the type comprising an operating element (13) forming a sleeve (12) and a driving element (15) respectively secured in rotation with the fixed (34) and rotating parts ( 32) of a bearing (30), the fixed part of the bearing being frictionally clamped between two radial bearing faces of the sleeve under the action of an elastic means (45), characterized in that the elastic means is incorporated in the fixed part of the bearing (34).  2. Self-centering clutch release bearing according to claim 1, characterized in that the elastic means (45) is formed at the periphery of a cheek (41) fitted onto the fixed ring of the bearing (34).  3. Self-centering clutch release bearing according to claim 2, characterized in that the elastic means (52) consists of a plurality of elastic tongues (51, 52, 53; 87) distributed over the periphery of the cheek (41).  4. Self-centering clutch release bearing according to claim 3, characterized in that the elastic tongues (51, 52, 53) are in corrugated form of peripheral orientation.  5. Self-centering clutch release bearing according to claim 3, characterized in that the elastic tongues (87) are legs of radial orientation forming an acute angle with a plane perpendicular to the axis of the stop.