FR2459921A1 - Roller bearing for diaphragm spring of automobile clutch - is annular coil spring mounted on thrust ring and expands or contracts according to orientation of diaphragm - Google Patents

Abstract

The annular bearing (23) has a circular cross section, positioned between e.g. the thrust ring (13) and the diaphragm spring (17). A pulley may use a displaceable cheek whose return movement is aided by the diaphragm. The diaphragm conical disc has a form (18) with inboard radial fingers (19), and spans a cheek flange (20) and the ring mounted bearing. The bearing may constitute a coil spring and form a roller bearing for the extremities of the diaphragm fingers (19), being capable of circumferential global expansion or contraction depending on the orientation of the diaphragm. Alternatively, an elastomeric bearing ring (23) can be used to reduce diaphragm wear.

Description

The present invention relates generally to specific contact support devices, one against the other, of two members mounted movable relative to one another between two distinct extreme positions.

Such a support device can for example intervene between two rotary members that do not have, relative to one another, a difference in relative speed of rotation.

This is the case for example for the speed variator pulleys comprising a flange mounted movable axially with respect to a support stop and an elastically deformable member axially, said diaphragm, interposed between said flange and said stop d 'Support, said diaphragm bearing axially, on one side, by its external periphery, on said flange, and, on the other side, by its internal periphery, on said support stop.

In such a variable speed drive pulley, there is therefore an axial support between, on the one hand the diaphragm, constituting a first member, and on the other hand the bearing stop, and / or the movable flange, constituting a second organ.

 Contact between such members is a wear generator, due to the relative movements between these members due to the tilting of the diaphragm in service, and this all the more so since the contact pressure between these members is relatively high.

In practice, on the side of the support stop, this wear mainly affects the diaphragm, the hardness of the latter being less than that of this support stop.

 It is therefore desirable to be able to insert between the two bodies in question a support device capable of minimizing wear.

 Such a drappui device can also inter-intervene between two rotary members which may have between them, before contact, a difference in relative speed of rotation.

 This is the case, for example, in certain diaphragm clutch mechanisms, which comprise, axially interposed between a pressure plate and a cover, an elastically axially de-calibratable member, called diaphragm, which, by its external peripheral zone, carries axially, on a first side, and along a first circumference, on said pressure plate, and on the other side, and along a second circumference of distinct radius, smaller or larger than that of the first, on said cover, and which, by its internal periphery, is intended to be subjected axially to an action member, push or pull, mounted axially movable, said clutch release bearing.

 In service, during a clutch release, there is an axial support of the clutch release bearing against the diaphragm and, as before, this axial support generates wear.

 This is the reason why the diaphragm of a diaphragm clutch mechanism is usually equipped, at its internal periphery, with a ring capable of receiving the action of the clutch release bearing, and of transmitting it to the diaphragm.

In the French patent filed under No. 69 42607 and published under No. 2,025,558, it has been proposed to produce this ring in the form of a support device comprising, in contact with one and the other organs between which it is interposed, an annular support piece, in practice a helical spring shaped as a ring, elastically deformable circumferentially between an expanded configuration and a retracted configuration.

 By its own elasticity, this annular support piece is able to absorb the changes in diameter experienced by the zone of action of the clutch release bearing on the diaphragm due to the tilting of the latter.

 But, if, in this French patent, the annular support part thus implemented is, on the side opposite the diaphragm, in contact with a surface which may be a flat surface, and therefore adjusted, it is not similarly on the side of the diaphragm, the latter being on the contrary always shaped in a hollow so as to form a housing for this annular support piece.

 There is therefore, on the side of the diaphragm, a curved support of this annular support piece on this diaphragm, which, if it is opposed to any relative radial displacement of the annular support piece with respect to the diaphragm, is necessarily a generator of wear between this annular support piece and this diaphragm due to the tilting movement specific thereto.

Similarly, to minimize wear, it has already been proposed to interpose an annular ring both between the diaphragm of a diaphragm clutch mechanism and the cover thereof, as between such a diaphragm and the plate pressure, as described in particular in German patent application No. 2,357,082.

 But such an annular ring has a well-defined diameter, so that, due to the tilting movement of the diaphragm, there is produced between this dipahragm and this ring, an inevitable relative radial dial movement generating wear, was it reduced .

It is still so when, as described in US Patent No. 2,359,104, is implemented an annular elastic ring in synthetic material to which a rigid housing circumferentially gives a well-defined configuration.

The present invention generally relates to a support device capable of minimizing wear and tear between the members between which it operates; it also relates to the applications of such a support device, in particular to speed variator pulleys and to diaphragm clutch mechanisms.

 The support device according to the invention, which is suitable for contact, the ur. against the other, of two members mounted movable relative to each other between two distinct extreme positions, and which is of the type comprising, in contact with one and the other of said members, an annular part d 'support, which is elastically deformable circumferentially between an expanded configuration and a retracted configuration, and which, for one of said members, is in contact with a regulated surface thereof, is characterized in that said annular piece of support constitutes in axial section of the rolling means and is in contact with a regulated surface both for one of the organs considered and for one of the latter.

By virtue of such an arrangement, each of the members considered is only the object of rolling contact with the annular support piece via which the transmission of an axial force takes place between them, and it As a result, this contact is only at the origin of minimal wear, even zero.

The characteristics and advantages of the invention will become apparent from the description which follows, by way of example, with reference to the appended schematic drawings in which:
Figure 1 is a partial axial sectional half-view of a speed variator pulley equipped with a support device according to the invention, for a position separated from the members that this pulley comprises
Figure 2 is a half cross-sectional view of this variable speed drive pulley, along the broken line II-II of Figure I
Figure 3 is a view similar to that of Figure 1, for a close position of the components of the variable speed drive pulley concerned
Figure 4 shows, on a larger scale, the detail of Figure 1 identified by an insert IV in this Figure 1, and illustrates the mode of intervention of the support device according to the invention
Figure 5 is a view similar to that of Figure 1 and relates to an alternative embodiment
Figure 6 is a partial axial sectional view of another speed variator pulley and illustrates another application to it of the support device according to the invention;
Figure 7 is a half view in axial section of a diaphragm clutch mechanism comprising a support device according to the invention;
Figure 8 is a view similar to that of Figure 7, for an alternative embodiment
Figure 9 is a half elevational view of the annular support piece that includes the support device according to the invention, for an alternative embodiment of this piece
Figure 10 is, on a larger scale, a sectional view of this annular support piece, in line with the axis of one of the rolling members which it comprises
Figure II is a view similar to that of Figure 10, for an alternative embodiment.

 Bes Figures i to 6 illustrate, by way of example, an application of the invention to a speed variator pulley.

 As is known, such a pulley is generally made up of two flanges, between which a belt intervenes, and which are mounted axially movable relative to one another, one of these flanges being assumed to be fixed and the other mobile.

 In the figures, and for simplification thereof, only the movable flange has been shown, under the general reference 10.

 It is a generally frustoconical part which, at its internal periphery, is integral with a support sleeve 17 slidably mounted on a shaft 12.

 This movable flange 10 is thus axially movable with respect to a support stop 13.

A key 14, acting between the support stop 13 and the support sleeve II of the flange 10, by means of a button 15 of this sleeve, secures in rotation said flange and said support stop.

Between the flange 10 and the support stop 13 is interposed an axially elastically deformable member 17, called a diaphragm, formed of a peripheral part 18 forming a Belleville washer, and of a central part fragmented into radial dogits 19.

On the first side, by its external periphery, the diaphragm 17 bears on the flange 10, by virtue of an axial flange 20 thereof provided for this purpose, and on the other side, by its internal periphery, it bears axially on the support stop 13.

 These arrangements are well known in themselves, and not forming part of the invention, they will not be described in more detail here.

In service, the two members which constitute the flange 10 and the abutment stop 13 move in relation to each other, along their axis, between a separated position, shown in FIG. 1, and a close position , shown in Figure 3.

In practice, the abutment stop 13 is most often axially fixed, and it is the flange 10 which approaches it; however, in the drawings, for simplification thereof, a reverse arrangement has been adopted.

For the separated position shown in FIG. 1, the diaphragm 17 generally has a frustoconical configuration, the concavity of which faces the flange 10; for the close position shown in FIG. 3, the diaphragm 17 still has a generally frustoconical configuration, but its concavity is reversed with respect to the previous one, this concavity now being turned towards the abutment support 13
In other words, between the separated position shown in Figure 1 and the close position shown in Figure 7, the diaphragm 17 is the subject of a tilting movement
Thus, in service, the diaphragm 17 has any configuration ranging between its extreme configuration with concavity turned towards the flange 10 and its ereme configuration with eoncavi-te facing towards the support stop 13, passing between these extreme configurations, by a substantially flat average configuration.

 In all cases, the diaphragm 17 provides the action of the support stop 13 with a set surface of revolution, that is to say a surface of which the meridian, in axial section, is a straight line.

 According to the invention, between the member that constitutes the diaphragm 17 and the member that constitutes the support stop 13, one of which is intended to act axially on the other, and which are movable relative to one another. the other between two distinct extreme positions, due to the tilting movement of the diaphragm, is axially interposed a support device 22.

 This support device 22 implements an annular support piece 23, which is elastically deformable circumferentially, between an expanded configuration of larger diameter and a retracted configuration of smaller diameter.

 According to the invention, this annular support piece 23 constitutes, in axial section, rolling means, and it is in contact with a surface adjusted both for the diaphragm 17 and for the support stop 13.

In the embodiment shown in FIGS. 1 to 4, it is a helical spring shaped as a ring, its two ends joining one another and being joined to one another, by example by welding.

Such a helical spring therefore has, in axial section, a circular contour, materialized by that of its turns, and is therefore suitable for constituting by itself rolling means.

For the diaphragm 17, it is in contact with a regulated surface 24 thereof, frustoconical or planar, as explained above.

 For the support stop 13, it is axially in contact with a regulated surface 25 of the latter, in practice flat, this surface being perpendicular to the axis of the assembly.

 Preferably, the annular part 23 does not by itself have a sufficient stiffness to allow it to counterbalance on its own the axial thrust of the diaphragm 17 for the separated position shown in FIG. 1, in particular because of the conical configuration of this diaphragm 17 for this separated position and the prestressing that it generally presents for the latter, the support stop 13 has a cylindrical surface 26 suitable for defining the corresponding configuration of said annular part 23; in practice, this cylindrical bearing surface 26 forms the internal lateral surface of a housing 27, the bottom of which forms the previously mentioned adjusted surface 25.

In practice also, this configuration of the spring constituting the annular part 23 for the separated position shown in FIG. 1 is an expanded prestressing configuration, for which the ring formed by this spring has a diameter DI overall, defined by the cylindrical bearing 26 of the support stop1
For this expanded prestressing configuration, the turns of the spring constituting this annular part 23 are all successively separated in pairs, as it appears in FIG. 2.

 Due to its prestressing, this spring is permanently the object of a radial stress which, as shown diagrammatically by the arrow FI in FIG. 4, tends to bring it back to a retracted configuration of smaller diameter.

 For the spaced-apart position of the flange 10 and of the abutment stop 13, this is prevented by the frustoconical configuration, concavi t facing the flange 10, which the diaphragm 17 then presents.

However, as the flange 10 passes into the close position, and the flattening which then results therefrom for the diaphragm 17, the spring constituting the annular support piece 23 is gradually released by this diaphragm 17, and can thus, under the effects of its prestressing, tend to occupy a configuration of smaller diameter.

In practice, and as shown diagrammatically in broken lines in FIG. 4, the spring constituting the annular support piece e? 3 thus reaches a configuration of minimum diameter D2, at a distance from the cylindrical surface 26 of the support stop 13 , when the diaphragm 17 is substantially flat.

 Anyway, from one of its configurations to another, the spring constituting the annular support piece 23 rolls without sliding, on the adjusted surfaces 24 and 25 in contact with which it is located, according to arrow F2 in Figure 4.

This rotation is done in harmony with the conferral cir contraction which develops jointly.

 For the rest configuration with a diameter D2 minimally ionized above, the turns of the spring constituting the annular support piece 13 are or are not contiguous.

 As the movement of the flange 10 continues, the diaphragm 17 passes, as mentioned above, from its substantially planar configuration, shown in broken lines in FIG. 4, to its frustoconical configuration, with a concavity turned towards the support piece 13 , shown in thin line in this figure 4.

 Jointly, and for reasons similar to those described above, the spring constituting the annular support piece 23 rolls without sliding on the adjusted surfaces 24, 25 in contact with which it is found, but, according to arrow F3 of Figure 4, that is to say in a reverse direction of rotation of the previous one.

it follows that it then passes from its retracted configuration of previous minimum diameter D2 to an expanded configuration of diameter D3 greater than the diameter D2 and at most equal to the diameter DI of its initial expanded configuration.

Thus, from the separated position of the flange 10 and the support stop 13 to the close position of these members, and conversely, no substantial friction develops between them, the support device interposed between these members ensuring rolling contact between them.

 It follows that the measurement of the support stop 13 and / or of the diaphragm 17 at their support is minimal, or even zero.

According to the variant embodiment illustrated in FIG. 5, the annular support piece used in the support device 22 according to the invention is a rod 33 made of elastic material.

In service, and independently of the axial crushing of which it is the object, this rod 33 is, as previously, the object of a bearing on the adjusted surfaces 24, of the diaphragm 17, and 25 of the bearing stop. 13, in contact with which it is.

 In the embodiment shown, the adjusted surface 25 of the abutment stop 13 is annularly bordered by surfaces with a connecting curve meridian 27 ', 27 ", both at its internal periphery and at its external periphery, for better confinement of the rod 33.

 In the foregoing, the support device 22 according to the invention is implemented between the diaphragm 17 and the support stop 13.

But, as illustrated in FIG. 6, a similar support device 22, with an annular support piece 23, a spring for example, can also be implemented between the diaphragm 17 and the flange 10, in favor for example a housing 27 with bottom 25 and internal cylindrical wall 26 formed for this purpose annularly in the axial rim 20 of this flange.

 Bes Figures 7 and 8 illustrate an application of the invention to a diaphragm clutch mechanism.

 As is known, such a mechanism comprises, axially interposed between a pressure plate 28 and a cover 29, an elastically deformable member axially 30, called a diaphragm, which, as before, comprises a peripheral part 31 forming a Belleville washer and a central part fragmented into radial fingers 32, and which, by its external periphery, carries axially, on a first side, and along a first circumference of radius RI, on the pressure plate 28, and, on the other side, along a second circumference of radius R2 distinct from radius R1 of the first, on the cover 29.

 As regards, as shown, a so-called "pushed" clutch mechanism, that is to say with push control, as described below, the radius R2 is less than the radius RI.

By its internal periphery, the diaphragm 30 is in fact intended to be subjected axially to an action member 35, called a clutch release bearing, which is mounted axially movable relative to the cover 29, and which, in this case, is a thrust member.

 These arrangements are well known in themselves, and not forming part of the present invention they will not be described in more detail here.

For the action of the clutch release bearing 35, the diaphragm 30 is equipped at its internal periphery with a ring 36.

 According to the invention, the ring 36 includes a support device 22 of the type of heavens described above.

 In the embodiment shown, the annular support piece used in this support device 22 is a helical spring 23 of the type described with reference to FIGS. 1 to 4.

However, it could just as easily be a rod of the type described with reference to FIG. 5.

 Anyway, this annular support piece 23 is housed in a housing 37 which is coupled to the diaphragm 30, and inside which are formed on the one hand the adjusted surface 25 and on the other the cylindrical bearing 26 associated with this annular part.

 In the embodiment illustrated in Figure 7, the housing 37 projecting, at its internal periphery, at least three pins 39, each of which is engaged axially between two consecutive axes of the radial fingers 32 of the diaphragm and which jointly provide centering of the housing 36 thereon and its rotational drive.

 In addition, in this case, the bolt clamp 37 is equipped with a cover 40 by tongues 41 from which it is snapped onto the diaphragm 30, these tongues 41 also being each engaged axially between two consecutive radial fingers 32 of the diaphragm 30 and slightly curved beyond it, towards its peripheral part 31.

As a variant, in FIG. 8, the housing 37 is coupled to the diaphragm 30 by elastically deformable tongues 42, which are for example three in number, and which jointly ensure not only the centering of the housing 37 with respect to the diaphragm 30 and its rotational drive, but also the axial maintenance of this housing 37 vis-à-vis this diaphragm.

In the embodiment shown, each of these elastically deformable tongues 42 is fixed by rivet, at one of its ends, to the housing 37, and, at the other of its ends, to a radial finger 32 of the diaphragm 30 .

 In the foregoing, the annular support part used is unitary.

 As illustrated in Figures 9 and 11, it is not necessarily so.

In the embodiments shown in these figures, the annular support part used in fact comprises on the one hand a support 45, which is generally shaped as a ring, and on the other hand rolling elements 46, which are circumferentially engaged on the support 45, from place to place.

 In the embodiment shown, the support 45 is an annular ring opened by a slot 47 to allow a change in diameter, and thus authorize the operation described in detail above.

However, as a variant, it could be a helical spring closed in a ring.

 In the embodiment illustrated in Figures 9 and 10, the rod 45 thus implemented has a regular circular configuration; as a variant, in FIG. 11, it is polygonal, so that, in line with each rolling member 46 which it carries, it has a straight section 48.

Anyway, between a rolling member 46 and the support 45 which carries it, there is preferably provided, as shown, a pad made of elastically deformable material 50.

 In the embodiments shown, the rolling members 46 are rollers.

 However, as a variant, it could also be rollers, balls or any other suitable running gear.

 The present invention is moreover not limited to the embodiments described and shown, but encompasses any variant embodiment and / or combination of their various elements.

 In particular, the annular support part used can be constituted by rollers or other circumferentially coupled two by two by springs.

 In addition, the application of the invention is not limited to variable speed pulleys or to diaphragm clutch mechanisms, but extends to any apparatus comprising two members movable relative to each other and resting against each other.

In particular, in the case of a diaphragm clutch mechanism, it goes without saying that a support device according to the invention can be associated with the diaphragm not only for interposition between it and the clutch release bearing, to constitute as previously, a ring attached to this diaphragm, but also for interposition between it and any one of the members that constitute the cover and the pressure plate between which this diaphragm is itself interposed.

it goes without saying also that the present invention can be applied to clutch mechanisms in which the clutch release bearing is in permanent abutment against the diaphragm, and / or to the diaphragm clutch mechanism of the so-called "pulled" type, it that is to say, by traction control instead of thrust, the radius R2 of the circumference along which the diaphragm bears on the cover being in this case greater than that RI of the circumference along which it bears on the pressure plate, and l 'action member being a traction member.

Claims (15)

1. Support device specific to the contact, one against the other, of two members mounted movable relative to each other between two distinct extreme positions, of the type comprising, in contact with one and the other of said members, an annular support piece, which is elastically deformable circumferentially between an expanded configuration and a retracted configuration and which, for one of said members, is in contact with a regulated surface thereof, characterized in that said annular support piece constitutes in axial section of the rolling means and is in contact with a regulated surface both for one of the organs considered and for the other of these.  2. Support device according to claim 1, characterized in that one of the members considered comprises a cylindrical bearing suitable for defining the configuration of the annular support piece for at least one of the extreme positions of said members.  3. Support device according to any one of claims 1, 2, characterized in that, for at least one of the extreme positions of the two members concerned, the annular support piece is in the expanded prestress configuration. 4. Support device according to claim 3, wherein the annular part comprises a helical spring shaped as a ring, characterized in that, for at least one of the extreme positions of the two bodies concerned, the turns of said helical spring are all successively discarded two by two.  5. Support device according to any one of claims n to 3, characterized in that the annular part comprises a support, which is generally shaped as a ring, and on which are circumferentially engaged, from place to place, organs bearing, such as rollers, rollers, balls or others. 6. Support device according to claim 5, characterized in that said support consists of an annular ring open by a slot.  7. Support device according to claim 6, characterized in that, in line with a rolling member, the support is rectilinear.  8. Support device according to any one of claims I to 7, characterized in that, between a rolling member and the support, there is provided a pad of elastically deformable material.  9. Support device according to any one of claims 1 to 3, characterized in that the annular piece of support implemented is constituted by rollers or the like circumferentially coupled two by two by springs. 10. Variable speed drive pulley of the type comprising a flange mounted movable axially with respect to a support stop and an elastically deformable member axially, said diaphragm, interposed between said flange and said support stop, said diaphragm bearing axially, on one side, by its external periphery, on said flange, and, on the other side, by its external periphery, on said support stop, characterized in that a support device conforming to any of claims 1 to 9 is interposed axially between, on the one hand the diaphragm, and, on the other hand, any one, at least, of the flange-abutment support members.  11. A diaphragm clutch mechanism of the type comprising, axially interposed between a pressure plate and a cover, an elastically deformable member axially, known as a diaphragm, which, by its external peripheral zone, carries axially, on a first side, and along a first circumference, on said pressure plate, and on the other side, and along a second circumference of radius distinct from that of the first, on said cover, and which, by its internal periphery, is intended to be subjected axially to an action member mounted axially movable, known as a clutch release bearing, characterized in that it comprises a support device according to any one of claims 1 to 9, associated with the diaphragm, for interposition between this dia pliragme and any one of the clutch release bearing-pressure plate-cover members.  12. Clutch mechanism according to claim '1, characterized in that, being a support device used for interposition between the diaphragm and the clutch release bearing, the annular support piece of this device support is housed in a housing which is coupled to the diaphragm, and in which are formed, for said annular support piece, an adjusted axial contact surface and a cylindrical surface.  13. Clutch mechanism according to claim characterized in that said housing has at least three projecting protrusions each of which is engaged axially between two consecutive radial fingers which usually comprises the diaphragm.  14. Clutch mechanism according to claim 13, characterized in that said housing is equipped with a cover by tabs from which it is snapped onto the diaphragm. 15. Clutch mechanism according to claim 12, characterized in that said housing is coupled to the diaphragm by elastically deformable tongues.