FR3066793A1 - DOUBLE CLUTCH WITH WEAR RETENTION, IN PARTICULAR FOR A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a dual clutch (1) with wear catch-up, in particular for a motor vehicle, comprising at least one reaction plate (4), a first and a second friction disk (5a, 5b), a first and a second second pressure plate (3a, 3b) actuated respectively by a first and a second diaphragm (9a, 9b), a fixed cover (6), first detection and wear-catching means mounted between the first diaphragm (9a) and the fixed cover (6), and second wear detection and retrieval means mounted between the second diaphragm (9b) and the second pressure plate (3b).

Description

Wear take-up clutch device, in particular for a motor vehicle

The present invention relates to a wear take-up clutch device, in particular for a motor vehicle.

A clutch device conventionally comprises a reaction plate, a movable pressure plate and a friction disc mounted between said reaction and pressure plates. The movement of the pressure plate is controlled by a diaphragm, itself controlled by a clutch bearing.

The pressure plate is thus movable between a clutch position in which the friction disc is clamped between said pressure and reaction plates, and a declutch position in which the friction disc is released. The use of the clutch device causes wear of the friction disc linings as well as the counter-materials of the associated pressure and reaction plates. This results in a variation of the position of the pressure plate with respect to the associated diaphragm and / or with respect to the reaction plate, generating a variation in the clamping force of the friction disc and a modification of the licking point and the stroke of the clutch bearing. Remember that the licking point is the position from which a torque can be transmitted through the clutch device.

A wear take-up clutch device is known from document FR 2 780 119. This device comprises a cover inside which is mounted a pressure plate intended to come to bear on a friction disc, a diaphragm interposed between the cover and the pressure plate, serving to actuate the pressure plate between a fully engaged position in which said pressure plate is pushed against the friction disc, and a fully disengaged position in which said pressure plate is moved of the friction disc by means of return means of the pressure plate.

Means for taking up the wear of the friction disc are interposed between the diaphragm and the pressure plate, and comprise at least one take-up member movable within a determined range and comprising a ramp cooperating with a counter-ramp turned on the side of the pressure plate, so as to adjust the distance between the diaphragm and the pressure plate and compensate for the wear of the friction disc as a function of the angular position of the ramp relative to the counter-ramp.

The device also comprises means for detecting wear, capable of authorizing the displacement of the movable take-up member in the event of wear of the friction disc and capable of preventing such displacement when this wear is not sufficient. , said detection means comprising at least one movable detection member, in a determined range, relative to the take-up member and comprising a ramp cooperating with a counter-ramp turned towards the side of the pressure plate.

The device finally comprises a pressing member coming to constrain the ramps of said movable members against the associated counter-ramps, the pressing member being able to cooperate with a fixed stop, for example the cover, so as to release said movable members when wear of the friction disc is detected. The movable take-up member is biased by means of a spring, so as to make up for the play between the latter and the pressing member, when said movable take-up member is released by the pressing member and by the diaphragm . Furthermore, the mobile detection member is biased by another spring so as to make up for the play between it and the pressing member, when said mobile detection member is released by the pressing member and by the diaphragm.

In operation, the assembly is subjected, alternately, to successive stages of clutching and disengaging.

In the clutch phase, the diaphragm presses on the pressure plate, by means of the play take-up member. In the clutch phase, the pressure plate is returned to its declutching position, by means of return means generally taking the form of elastically deformable tongues.

When the friction disc is not worn and the counter-materials of the pressure and reaction plates are not worn, the pressing member constantly maintains the detection member and the take-up member in preload: said members are immobilized.

In the event of wear, the pressing member comes to bear on the stop and a clearance is created between the pressing member and the detection member. As the latter is constrained by a spring, it is moved so as to fill the aforementioned clearance. In the engaged position, the force applied by the diaphragm to the take-up member prevents the latter from moving, by pressing and friction on the pressure plate. Then, when the diaphragm is moved into its disengaged position, the pressure plate return tabs tend to press the pressure plate against the play take-up member, and the play take-up member against the diaphragm. The force exerted by the return tabs is relatively low so as to allow, despite the friction in play, a movement of the play take-up member, under the effect of the stress applied by the corresponding spring. This movement makes it possible to make up for the play between the pressing member and the take-up member. This compensates for the wear of the friction plate as well as the wear of the counter-materials of the associated pressure and reaction plates.

Such an operation requires in particular the use of return means of the pressure plate exerting relatively low forces, to allow the displacement of the take-up member despite the friction in play. This is detrimental to operation since such return means can transmit axial vibrations and generate pumping phenomena of the pressure plate.

In order to remedy this drawback, patent application FR 3 009 592, in the name of the Applicant, proposes a clutch device with wear compensation, in particular for a motor vehicle, comprising a pressure plate intended to come to bear on a clutch device friction disc, a diaphragm for actuating the pressure plate between a fully engaged position in which said pressure plate is pushed against the friction disk, and a fully disengaged position in which said pressure plate pressure is moved away from the friction disc by means of return means of the pressure plate. The clutch device comprises a wear take-up mechanism comprising: - means for taking up the wear of the friction disc being interposed between the diaphragm and the pressure plate, said wear take-up means comprising at least one take-up member movable within a determined range and comprising a ramp cooperating with a counter-ramp turned towards the side of the pressure plate, so as to adjust the distance between the diaphragm and the pressure plate and compensate for the wear of the friction disc by function of the position of the ramp relative to the counter-ramp, - wear detection means capable of authorizing the displacement of said movable take-up member in the event of wear of the friction disc and capable of preventing such displacement when this wear is not sufficient, said detection means comprising at least one movable detection member, within a determined range, relative to the member d e mobile take-up and comprising a ramp cooperating with a counter-ramp turned towards the pressure plate, - at least one pressing member constraining at least the ramp of the detection member against the associated counter-ramp, the pressing member being able to cooperate with a fixed stop so as to release said movable members when wear of the friction disc is detected, - the movable take-up member being urged so as to move when said movable take-up member is released by the diaphragm, the movable detection member being biased so as to move and catch up, at least in part, the clearance between the latter and the pressing member, when said mobile detection member is released by the pressing member and through the diaphragm.

In addition, the diaphragm can release the detection member and prevent the displacement of the take-up member, in the fully engaged position, and the diaphragm can release the take-up member and prevent the movement of the detection member, by fully disengaged position, the diaphragm always coming to bear on at least one of said members between its fully engaged and totally disengaged positions.

In this way, the pressure plate return means can exert a significant effort, this effort being taken up by the movable take-up member then by the diaphragm, or by the movable detection member then by the diaphragm, depending on the position of the diaphragm. Indeed, during their movements, said movable members are not subjected to the force exerted by the return means of the pressure plate and it is therefore possible to easily request their movement, in the event of wear.

As indicated above, the fact of having means for restoring the pressure plate exerting a significant force, such as for example spring tongues having a high stiffness, makes it possible to limit the transmission of axial vibrations and to avoid pumping phenomena of the pressure plate. The mobile detection member and the mobile take-up member are stressed by elastic members, for example tension springs.

In particular, at least one first tension spring extending circumferentially is mounted between the detection member and the pressure plate, or between the detection member and a cover rotatably coupled to the pressure plate. Second tension springs extending circumferentially are mounted between the detection member and the take-up member. These second springs provide the motorization function of the take-up member with respect to the detection member.

The counter-ramp of the pressure plate cooperating with the detection member and the counter-ramp cooperating with the take-up member are identical.

Patent application FR 3 009 592 also applies such wear take-up means to a double clutch.

It will be recalled that a double clutch makes it possible in particular to alternately couple the shaft of the vehicle engine with two coaxial shafts for the input of a gearbox, which may be of the robotic type.

Thus, a double clutch makes it possible to change gear ratio while maintaining the transmission of engine torque to the wheels of the vehicle. Indeed, the two clutches are associated respectively with even and odd gear ratios. When changing gear, a first clutch is disengaged while the second clutch is engaged, so that the engine torque is gradually transferred from the first to the second clutch.

Each clutch comprises a mechanism comprising a diaphragm intended to cooperate with a pressure plate integral in rotation with the cover and the motor shaft. Each diaphragm is movable by means of a corresponding clutch stop, between a rest position and an active position. Depending on the type of clutch, the active position of the diaphragm corresponds to a coupling or uncoupling of the motor and transmission shafts and the rest position of the diaphragm corresponds to a decoupling or coupling of these shafts. This is called the normally open clutch and the normally closed clutch, respectively.

For safety reasons, at least one of the clutches is of the normally open type.

The clutch bearing is controlled by an actuator controlled by an electronic computer in order to exert a predetermined force on the diaphragm and to move it over a given distance.

The pressure plate of each clutch, biased by the corresponding diaphragm, is intended to clamp a friction disc on a corresponding reaction plate. A reaction plate can be provided for each clutch. Alternatively, a single reaction plate common to the two clutches is used, mounted between the two friction discs.

Each friction disc is linked in rotation to an input shaft of the gearbox and each reaction plate is for example integral in rotation with a flywheel linked to the motor shaft. Thus, the tightening of a friction disc between the corresponding pressure and reaction plates allows the transmission of a torque between the motor shaft and the shaft of the associated gearbox.

As before, the use of clutches causes wear of the friction linings of the friction discs as well as the counter-materials of the associated pressure and reaction plates. This results in a variation of the position of each pressure plate relative to the associated diaphragm and / or to the reaction plate, generating a variation in the force of tightening of the friction disc and a modification of the licking point and the clutch bearing race. In this case, the licking point is the position from which part of the engine torque is transmitted to the gearbox shaft when the clutch is closed.

In general, such wear is more present at the friction disc and the pressure and reaction plates belonging to the first clutch, that is to say to the clutch associated with the odd gear ratios. Thus, when the double clutch has only one wear take-up mechanism according to the invention, it preferably forms part of the first clutch. Of course, the double clutch according to the invention may include both wear take-up mechanisms fitted to the first clutch and a mechanism fitted to the second clutch.

Patent application FR 3 009 592 discloses in particular the use of a first wear take-up mechanism fitted to the first clutch and a second wear take-up mechanism fitted to the second clutch.

In this patent application is described a double clutch comprising a reaction plate intended to be coupled in rotation to a driving shaft, a first and a second friction disc, intended to be coupled respectively to a first and a second driven shafts, a first and second pressure plates, actuated respectively by a first and a second diaphragm so as to clamp or release the first and the second friction disc on the reaction plate, the first pressure plate being fixedly connected to a movable cover in translation relative to the reaction plate, and being actuated by pressing the first diaphragm on the movable cover, first means for detecting and compensating for the wear of the first friction disc being interposed between the first diaphragm and the movable cover, second means for detecting and compensating for the wear of the second friction disc, being interposed between the second diaphragm hragme and the second pressure plate.

In operation, the support of each diaphragm is able to switch from the take-up member to the detection member, and vice versa, between the clutch and disengage phases. It has been found that the axial position of the radially internal periphery of the diaphragm, that is to say the position of the clutch bearing, at the time of such a tilting, varies as wear and tear friction disc is caught. This phenomenon tends to increase the stroke of the clutch bearing with the wear of the friction disc, which in particular has a negative impact on the axial dimensions and on the operation of the device. The invention aims to remedy, in whole or in part, the problems mentioned above. To this end, it offers a wear take-up clutch device, in particular for a motor vehicle, comprising: - a reaction plate intended to be coupled in rotation to a driving shaft, around an axis of rotation, - a friction disc, intended to be coupled to a driven shaft, - a pressure plate actuated by a diaphragm so as to tighten or release the friction disc on the reaction plate, - a cover, - detection and take-up means wear, capable of catching the wear of the friction disc, the wear detection and take-up means being mounted between the diaphragm and the cover and comprising: wear take-up means interposed between the diaphragm and the cover , said wear take-up means comprising at least one take-up member movable in a determined range and comprising a ramp cooperating with a counter-ramp secured to the cover, so as to adjust the d distance between the diaphragm and the cover and compensate for the corresponding wear as a function of the position of the ramp with respect to the counter-ramp, wear detection means capable of authorizing the displacement of said take-up member in the event of wear and capable of preventing such displacement when this wear is not sufficient, said detection means comprising at least one movable detection member, within a determined range, relative to the take-up member and comprising a ramp cooperating with a counter-ramp secured to the cover, the inclination of the counter-ramp cooperating with the take-up member is different from the inclination of the counter-ramp cooperating with the detection member.

Advantageously, the inclination of the ramp of the mobile take-up member being different from the inclination of the ramp of the detection member.

The production of two counter-ramps or two ramps of different inclinations relative to one another makes it possible to adjust the axial position of the radially internal periphery of the diaphragm at the time of the tilting of the diaphragm support of the 'catching member to the detection member, or vice versa. In this way, the position of the clutch release bearing at the time of such a tilting does not vary, or almost does not, as the wear of the friction disc is caught.

The counter-ramps can be locally combined, for example at one of the ends of said counter-ramps or at a median zone located between said ends.

The device may include at least one pressing member which constrains at least the ramp of the detection member against the associated counter-ramp, the pressing member being able to cooperate with a fixed stop so as to release the detection member when wear is detected, the catching member being biased so as to move when said catching member is released by the diaphragm, the detection member being biased so as to move and catch up, at least in part, the clearance between the latter and the pressing member, when said detection member is released by the pressing member and by the diaphragm. The take-up member and the detection member may be annular, coaxial, and may be able to pivot around the axis of rotation, the inclination of the counter-ramp cooperating with the detection member relative to the plane radial being defined, more or less 5%, by the following relation:

in which: - CDR is the inclination of the counter-ramp cooperating with the detection member with respect to the radial plane, in mm / °, - CMR is the inclination of the counter-ramp cooperating with the take-up member by relative to the radial plane, in mm / °, RBUtée is' at a distance between the support of a clutch bearing on the diaphragm fingers and the axis of rotation, in mm, - Rdr is the distance between the support of the detection member on the diaphragm and the axis of rotation, in mm, - Rmr is the distance between the support of the take-up member on the diaphragm and the axis of rotation, in mm, - kdiaph is the stiffness constant of the diaphragm fingers, in N / mm, - Load, is the axial force generated by the stop on the diaphragm, - ΘΜΚ is the rotation of the take-up member relative to the axis of rotation. The take-up member and the detection member may be annular, coaxial, and may be able to pivot around the axis of rotation, the inclination of the ramp of the detection member relative to the radial plane being defined , more or less 5%, by the following relation:

in which: - C „„ is the inclination of the ramp of the detection member with respect to the radial plane (in mm / °),

Cwest the inclination of the ramp of the take-up member with respect to the radial plane (in mm / °),

RBUtée is' θ distance between the support of a clutch bearing on the diaphragm fingers and the axis of rotation (in mm), - Rdr is the distance between the support of the detection device on the diaphragm and the axis of rotation (in mm), - Rmr is the distance between the support of the take-up member on the diaphragm and the axis of rotation (in mm), kdiaph is the stiffness constant of the fingers of the diaphragm (in N / mm),

Load ,, is the axial force generated by the stop on the diaphragm (in N), QMR is the rotation of the take-up member relative to the axis of rotation.

The above relations make it possible to calculate the theoretical value of the inclination of the counter-ramp cooperating with the detection member or of the ramp of the detection member with respect to the radial plane as a function of the other characteristics of the device. The actual inclination may vary to a certain extent from the theoretical inclination, so as to take particular account of the deformation of the parts and / or the dimensional or mounting tolerances.

The cover can be fixed axially relative to the pressure plate.

The device may comprise at least one spacer integral with the cover, the ramp of the take-up member and / or the ramp of the detection member being formed on the spacer.

In this case, it is possible to produce spacers comprising counter-ramps having different types of geometry, an operator being able to choose a spacer according to the characteristics of the device and then mount said spacer on the cover.

Furthermore, it may be easier to carry out one and / or the other counter-ramps on a separate part of the cover rather than directly on the cover. The spacer may be annular in shape or be formed by a series of added angular segments. The inclination of the ramp of the take-up member with respect to the radial plane may be between 0.005 and 0.3 mm / °, the inclination of the ramp of the detection member with respect to the radial plane may be between between 0.004 and 0.5 mm / °.

The diaphragm can release the movable detection member and prevent the displacement of the movable take-up member, in the fully engaged position, the diaphragm being able to release the movable take-up member and prevent the displacement of the movable detection member, in fully disengaged position, the diaphragm always coming to bear on at least one of said movable members between its fully engaged and totally disengaged positions. The detection member may include an end capable of serving to support the diaphragm and an end comprising at least one ramp, cooperating with the counter-ramp associated with the cover. The take-up member may comprise an end capable of serving to support the diaphragm and an end comprising at least one ramp, cooperating with the counter-ramp associated with the cover.

The device may include a stop member connected to the pressing member, the stop member being designed to separate the pressing member from the detection member and / or from the take-up member in the event of wear. The pressing member may include at least one elastic tongue, one end of which is capable of coming to bear on the mobile detection member or on the corresponding mobile take-up member. The invention may relate in particular to a simple clutch, of the normally closed type and of the pulled or pushed type. The invention can also be applied to a hybrid architecture, the clutch then being able to be of the normally open type.

In such a case, the cover can be secured to the reaction plate.

Alternatively, the invention may relate to a double clutch. In such a case, the double clutch may comprise: - at least one reaction plate intended to be coupled in rotation to a driving shaft, around an axis of rotation, - a first and a second friction disc carrying linings of friction, intended to be coupled respectively to a first and a second driven shaft, - a first and a second pressure plate actuated respectively by a first and a second diaphragm so as to tighten or release the first and the second friction disc on the reaction plate, the first pressure plate being fixedly connected to a cover movable in translation relative to the reaction plate, and being actuated by pressing the first diaphragm on the movable cover, - a fixed cover, fixed to the reaction plate and accommodating the second pressure plate, the second friction disc and / or the second diaphragm, - first means for detecting and taking up wear, capable of catching the wear of the first friction disc, the first wear detection and take-up means being mounted between the first diaphragm and the fixed cover, - second wear detection and take-up means, capable of catching the wear of the second friction disc, the second wear detection and take-up means being mounted between the second diaphragm and the second pressure plate, the first wear detection and take-up means and the second wear detection and take-up means wear each comprising: wear take-up means inserted between the first diaphragm and the fixed cover, or respectively between the second diaphragm and the second pressure plate, said wear take-up means comprising at least one movable take-up member in a determined range and comprising a ramp cooperating with a counter-ramp turned towards the side of the fixed cover or of the second pressure plate, so as to adjusting the distance between the first diaphragm and the fixed cover, or respectively between the second diaphragm and the second pressure plate and compensating for the corresponding wear depending on the position of the ramp relative to the counter-ramp, detection means wear capable of authorizing the displacement of said movable take-up member in the event of wear and capable of preventing such displacement when this wear is not sufficient, said detection means comprising at least one movable detection member, in a determined range, relative to the movable take-up member and comprising a ramp cooperating with a counter-ramp turned towards the side of the fixed cover or of the second pressure plate, the inclination of the ramp of the movable take-up member of the first wear detection and compensation means and / or second wear detection and compensation means being different from the inclination of the ramp of the detection member of the first wear detection and take-up means and / or second wear detection and take-up means.

It will be noted that each clutch can thus be equipped with wear take-up means having a reduced axial and radial bulk. The size of the double clutch is therefore significantly reduced. The mobile take-up member and the detection member of the first wear detection and take-up means can be located radially outside or radially inside the mobile take-up member and the wear member. detection of the second wear detection and take-up means, so as to reduce the axial size.

The device may include a stop member connected to the pressing member, the stop member being designed to separate the pressing member from the detection member and / or from the take-up member in the event of wear, l the abutment member being connected to the pressing member in an area situated between the detection member and the take-up member, preferably halfway between the detection member and the take-up member.

In this way, the tilting effect of the pressing member is limited, such tilting having an influence on the positions of the actual bearing zones of the pressing member on the detection member and / or on the member. catch-up. The aforementioned characteristic thus makes it possible to control the position of said movable members, so as to guarantee the proper functioning of the corresponding detection and take-up wear means. The pressing device can interact with the fixed cover or the movable cover by means of an additional part. The abutment member may have one end bearing on the fixed cover or on the movable cover, and one end connected to the pressing member.

The clutch device according to the invention may also include one or more of the following characteristics: - the pressure plate is returned to its disengaged position, opposite the reaction plate, by first elastic return means, such as for example elastic return tongues mounted between the pressure plate and the reaction plate, - said elastic tabs ensure the rotation coupling of the reaction plate with the pressure plate, - the counter-ramps are provided on the part radial of the corresponding cover, - the detection member is located radially outside the corresponding wear take-up member, - the detection member and the take-up member comprise at least one zone in which they are radially spaced from each other, - the pressing member exerts a pressing force distributed between the detection member and the take-up member and the axial component of this force along the X axis can be applied to an application radius located between the detection member and the take-up member. the detection member and the take-up member, of generally circular shape, comprise at least one zone provided with bulges in which said movable members are locally spaced from one another in the radial direction, the pressing member coming to press on the corresponding ends of the movable members at the level of said zone provided with bulges, - the end of the stop member which is connected to the pressing member is housed in said zone provided with bulges.

More specifically, the double clutch may include one or more of the following characteristics: the first clutch and / or the second clutch are of the normally open type, the double clutch has a single reaction plate serving to support it of the first friction disc and of the second friction disc, -the first diaphragm is in the form of an elastic annular sheet and is mounted to pivot around the bearing areas of the movable cover, - the second diaphragm is in the form of an elastic annular sheet, the radially outer periphery of which is pivotally mounted relative to the fixed cover, - an elastic member keeps the radially external periphery of the second diaphragm in abutment on the fixed cover, - the fixed cover comprises radial flanges serving to fixation on the reaction plate, connected to an annular part surrounding, at least in part, the second pressure plate , the second friction disc and / or the second diaphragm, said annular part of the fixed cover being extended by an annular part extending radially inwards, - the counter-ramp is formed on the radial part of the fixed cover, - the movable cover has a radially external part extending from the first pressure plate and partially surrounding the fixed cover, extended by a part extending radially inwards and serving to support the first diaphragm, - a first elastic member, such as for example a tension spring extending circumferentially, is mounted between the detection member, on the one hand and the fixed cover or the second pressure plate, on the other hand, - a second member elastic, such as a pin-shaped spring, is mounted between each detection member and the corresponding take-up member, the first elastic member exerts a force tangential or circumferential greater than the tangential or circumferential force exerted by the second elastic member, the length of the first elastic member is large, so as to be able to request the displacement of the detection member over a large angular range, for example understood between 30 and 120 °, the pressing member is fixed to the fixed cover at a first end, and is capable of coming to bear, at a second end, on the detection member and on the wear take-up member corresponding, for example on the first movable detection and take-up members, so as to constrain the ramps in abutment on the counter-ramp, - the stop member comprises a first end fixed, for example by riveting, radially between the detection member and the corresponding wear take-up member, preferably radially midway between said movable members, and a second cylindrical end eu forming an enlarged head of larger dimension than the rest of the stud and defining a shoulder, - the enlarged head of the abutment stud is capable of coming to bear on a radial surface of the movable cover or of the fixed cover, - the enlarged head of the abutment pad is intended to come to bear on the corresponding radial surface when the displacement of the corresponding pressure plate is significant, that is to say when there is wear of the linings of the friction disc and / or against associated pressure plate and reaction plate materials. The invention will be better understood and other details, characteristics and advantages of the invention will appear on reading the following description given by way of nonlimiting example with reference to the accompanying drawings in which: - Figure 1 is a view in perspective with partial cutaway, of a double clutch according to an embodiment of the invention, - Figure 2 is an exploded view, in perspective, of the double clutch, - Figure 3 is an axial sectional view of the device d 'clutch, - Figure 4 is a perspective view of part of the double clutch, - Figure 5 is a detail view, in perspective, of the fixed cover, - Figures 6 and 7 are schematic views illustrating the operation of the first clutch, in the absence of wear, - Figures 8 to 11 are schematic views illustrating the operation of the first clutch, in the event of wear, - Figure 12 is a view corresponding to Figure 6, illustrating an alternative embodiment of the invention, FIGS. 13 and 14 are schematic views intended to illustrate the development of the tipping point, respectively in the case of a device of the double clutch type according to the prior art and in the case of a device of the double clutch type according to the invention, FIGS. 15 and 16 are schematic views aiming to illustrate it the evolution of the tipping point, respectively in the case of a device of the simple clutch type according to the prior art and in the case of a single clutch type device according to the invention.

A double clutch 1 with wear take-up according to an embodiment of the invention is shown in FIGS. 1 to 5. This is intended to couple a motor with a first and a second input shaft of a gearbox. speeds (not shown). The axis of the double clutch is referenced X. The double clutch 1 comprises first and second clutches 2a, 2b (also called clutch mechanisms) for shifting ratios of different parities.

The first clutch 2a has a first pressure plate 3a and a reaction plate 4 between which extends a first friction disc 5a. The first pressure plate 3a is coupled in rotation to the reaction plate 4 and is movable in translation relative to the latter, between a engaged position and a disengaged position, in which it clamps the first friction disc 5a on the plate. reaction 4, or respectively releases the first friction disc 5a.

The reaction plate 4 is fixed on a cover 6 called a fixed cover, itself intended to be coupled to the motor shaft. The first friction disc 5a is intended to be coupled to the first input shaft of the gearbox. Thus, in the engaged position of the first clutch 2a, the motor shaft is coupled to the first input shaft of the gearbox.

The first pressure plate 3a is fixed on a cover 7 movable in translation relative to the reaction plate 4 and to the fixed cover 6, and extending forward. First elastic return tongues 8a are mounted between the first pressure plate 3a and the reaction plate 4.

The first clutch 2a further comprises a first diaphragm 9a in the form of an elastic annular sheet, and is mounted to pivot around bearing areas 10 of the movable cover 7.

As is conventional in itself, the diaphragm 9a has a radially external annular part 9’a from which fingers 9 ″ a extend radially inward (FIG. 1).

The control of the first clutch 2a is conventionally done by means of a first clutch stop (not shown) cooperating with the radially internal periphery of the first diaphragm 9a, that is to say with the radially internal ends of the fingers 9 ” at. The first diaphragm 9a forms a lever transmitting the force applied by the first control stop to the first pressure plate 3a, via the movable cover 7.

In order to allow effective clamping of the first friction disc 3a, the first diaphragm 9a is preloaded at rest. Without this preload, the first diaphragm 9a would be, at rest, in a state of elasticity requiring a start of travel of the first control stop relatively large to apply an effective clamping force on the first friction disc 5a. When the first clutch bearing is actuated, it balances the preload of the first diaphragm 9a before starting to tighten the first friction disc 5a. The preload of the first diaphragm 9a makes it possible to reduce the approach stroke of the first clutch stop in order to tighten the first friction disc 5a, and to always have a minimum preload effort, for example on the ball bearing of the first clutch bearing and on the ball bearing which supports the double clutch 1. This increases the service life of said bearings and limits the vibrations of the double clutch 1.

The first clutch 2a is of the normally open type. The rest position of the first diaphragm 9a therefore corresponds to a disengaged state of the first clutch 2a. The first diaphragm 9a preferably has a portion of the Belleville washer type making it possible to return the first diaphragm 9a to its rest position.

In the rest position of the first diaphragm 9a, that is to say when the first stop exerts little or no force on the first diaphragm 9a, the first diaphragm 9a therefore does not exert (or little) force on the first pressure plate 3a. The first pressure plate 3a is spaced from the reaction plate 4 by means of the elastic tongues 8a, so as to release the first friction disc 5a.

The second clutch 2b comprises a second pressure plate 3b, and a second friction disc 5b extending radially and interposed axially between the reaction plate 4 and the second pressure plate 3b. The same reaction plate 4 is thus used for the two clutches 2a, 2b, each friction disc 5a, 5b being disposed on the side of one of the two bearing faces of the reaction plate 4. Second elastic return tabs 8b are mounted between the second pressure plate 3b and the reaction plate 4.

The second pressure plate 3b is coupled in rotation to the reaction plate 4 and is movable in translation relative to the latter, between a engaged position and a disengaged position, in which it clamps the second friction disc 5b on the plate. reaction 4, or respectively releases the second friction disc 5b.

The second friction disc 5b is coupled to the second input shaft of the gearbox. Thus, in the engaged position of the second clutch 2b, the motor shaft is coupled to the second input shaft of the gearbox.

The second clutch 2b further comprises a second diaphragm 9b in the form of an elastic annular sheet, the radially outer periphery of which is pivotally mounted relative to the fixed cover. An elastic member 11 (Figure 3) maintains the radially outer periphery of the second diaphragm in abutment on the fixed cover 6, by means of an annular ring 12.

The control of the second clutch 2b is conventionally done by means of a second clutch stop (not shown) cooperating with the radially internal periphery of the second diaphragm 9b, by means of a force transmission member (not shown ). The second diaphragm 9b forms a lever transmitting the force applied by the second clutch bearing to the second pressure plate 3b, in order to allow effective clamping of the second friction disc 5b.

The second clutch 2b is also of the normally open type. In the rest position of the second diaphragm 9b, that is to say when the second control stop exerts little or no force on the second diaphragm 9b, the second diaphragm 9b does not exert (or little) d 'effort on the second pressure plate 3b. The second pressure plate 3b is moved away from the reaction plate 4 by means of the elastic tongues 8b, so as to release the second friction disc 3b.

The fixed cover 6 comprises (FIGS. 2 and 4), from the rear to the front, radial flanges 6a used for fixing to the reaction plate 4, connected to an annular part 6b surrounding, at least in part, the second pressure plate 3b, the second friction disc 5b and / or the second diaphragm 9b. Said annular part 6b is extended by an annular part 6c extending radially inwards.

Furthermore, the movable cover 7 comprises a radially external part 7a extending forward from the first pressure plate 3a and partially surrounding the fixed cover 6, extended at the front by a part 7b extending radially towards inside and serving to support 10 of the first diaphragm 9a.

In order to compensate for the wear of the first friction disc 5a, the first pressure plate 3a and / or the reaction plate 4, the first clutch 2a is equipped with first means for detecting and taking up wear.

The first take-up and wear detection means equipping the first clutch 2a are interposed axially between the fixed cover 6 and the first diaphragm 9a, more precisely interposed axially between the radial part 6c of the fixed cover 6 and the first diaphragm 9a.

The first take-up and wear detection means comprise a first movable take-up member 13a in the form of a ring having an end 13'a against which the first diaphragm 9a is capable of coming to bear, and one end comprising at least one ramp 14a extending circumferentially, cooperating with an associated counter-ramp 15a formed directly on the radial part 6c of the fixed cover 6 (see FIGS. 4 and 5 for example). Of course, the counter-ramp 15a can be formed by an independent piece or spacer, fixed to the fixed cover 6.

The first take-up and wear detection means also comprise a first movable detection member 16a in the form of a ring having an end 16'a against which the first diaphragm 9a is capable of coming to bear, and a end comprising at least one ramp 17a extending circumferentially, cooperating with a counter-ramp 15'a of the radial part 6c of the fixed cover 6 (see FIG. 6 for example). The counter-ramp 15’a can be formed by an independent piece or a spacer.

FIG. 5 shows the counter-ramp 15a of the cover 6 cooperating with the take-up member 13a and the counter-ramp 15'a of the cover 6 cooperating with the detection member 16a locally combined, in this case, at the start ramp formed by the end 25.

The two movable members 13a, 16a are concentric and separated from each other, the first detection member 16a being located radially outside the first wear take-up member 13a. Alternatively, the respective positions of said movable members 13a, 16a can be reversed. Note however that the possibility of reversing the movable members 13a, 16a is linked to the internal architecture of the mechanism.

Centering means, such as for example studs, ensure the correct positioning of the movable members 13a, 16a.

A first elastic member 18a, such as for example a tension spring extending circumferentially, is mounted between the first detection member 16a and the fixed cover 6.

A second elastic member 19a, such as for example a pin-shaped spring, is mounted between the first detection member 16a and the first take-up member 13a.

The length of the first spring 18a is large, so as to be able to request the movement of the first detection member 16a over a large angular range (for example between 30 ° and 120 °).

The first clutch 2a also comprises at least a first pressing member 20a (FIG. 2) being in the form of an elastic tongue exerting an axial force. Said tongue 20a is fixed to the fixed cover 6, at a first end, and is capable of coming to bear, at a second end, on the first detection member 16a and possibly on the first wear take-up member 13a, so to force them to bear on the radial part 6c of the fixed cover 6.

An abutment pad 21a (see in particular Figure 6) is fixed on the second end of said tongue 20a. The stop stud 21a has in particular a first end 22a fixed, for example by riveting, to the tongue 20a and a second cylindrical end 23a forming an enlarged head of larger dimension than the rest of the stud 21a and defining a shoulder. The stud 21a passes through a hole in the movable cover 7 and is capable of coming to bear on a radial surface 7b of the movable cover 7.

In particular, the enlarged head 23a of the abutment pad 21a is intended to come to bear on said radial surface 7b when the displacement of the first pressure plate 3a is significant, that is to say when there is wear on the linings of the first friction disc 5a and / or of the counter-materials of the first pressure plate 3a and of the reaction plate 4.

As illustrated in Figure 5, the slopes of the counter-ramps 15a and 15’a have different inclinations.

The operation of the first wear detection and compensation means will now be described with reference to FIGS. 6 to 11.

As illustrated diagrammatically in FIGS. 6 and 7, the first take-up and wear detection means are inoperative when the linings of the first friction disc 5a are not or only slightly worn and the counter-materials of the first pressure plate 3a and the associated reaction plate 4 are not worn, for example when the cumulative axial wear is less than 0.05 mm.

As illustrated in FIG. 6, in the fully engaged position and in the absence of wear, the first diaphragm 9a comes to bear on the first take-up member 13a, so as to push the first pressure plate 3a against the elastic return tabs 8a. The first pressure plate 3a and the corresponding reaction plate 4 (axially fixed) then enclose the first friction disc 5a carrying the linings. In this position, the head 23a of the abutment pad 21a is flush with the radial surface 7b of the movable cover 7.

In addition, as illustrated in FIG. 7, in the fully disengaged position and in the absence of wear, the first diaphragm 9a comes to bear on the first detection member 16a, a clearance being created between the first diaphragm 9a and the corresponding end 13'a of the first take-up member 13a.

It can thus be seen that, in the absence of pronounced wear, the second end of the elastic tongue 20a and / or the first diaphragm 9a keeps the first detection member 16a and the first take-up member 13a in abutment on the fixed cover 6 , whatever the operating phase of the first clutch 2a (clutch / disengage). In this case, the resistive torque generated by the friction between said members 13a, 16a and the fixed cover 6 is greater than the torque exerted by the springs 18a, 19a. Said members 13a, 16a are therefore immobilized in rotation relative to the fixed cover 6, whatever the operating phase of the first clutch 2a.

Figures 8 to 11 illustrate the case where the linings of the first friction disc 5a (or the counter-materials of the first pressure plate 3a and the reaction plate 4) show wear, which must be taken up in order to '' avoid a malfunction of the first clutch 2a.

In this case, as illustrated in FIG. 8, the head 23a of the abutment stud 21a comes to bear on the radial surface 7b of the movable cover 7, in the fully engaged position, so that the second end of the elastic tongue 20a comes off of the corresponding secondary end of the first detection member 16a. The secondary end is called the end against which the tongue 20a comes to bear. This secondary end can be offset from the end 16’a used to support the diaphragm 9a. A clearance j1 therefore forms between said secondary end of the first detection member 16a and the second end of the tongue 20a. Thus, in particular, there may be an axial clearance between the first pressing member 20a and the corresponding secondary end of the first wear take-up member 13a, even though the first pressing member 20a is in contact with the end. corresponding secondary of the first detection member 16b.

It is possible in some cases that the end 16’a of the first detection member 16a and the secondary end of the first detection member 16a are combined. Likewise, it is possible that the end 13 ′ of the first take-up member 13a and the secondary end of the first take-up member 13a are combined.

The first detection member 16a, which is then no longer subjected to an axial force, is rotated by the first elastic member 18a, so as to at least partially fill the clearance j1 (FIG. 9). During this rotation, the second elastic member 19a is constrained.

The rotation of the first detection member 16a is for example stopped when the corresponding secondary end of the first detection member 16a again comes to bear on the second end of the tongue 20a. It will be noted that, during this phase, the first take-up member 13a is held in abutment on the fixed cover 6 by the first diaphragm 9a. It is therefore immobilized in rotation relative to the fixed cover 6.

During the following declutching phase, the first diaphragm 9a transfers its support from the first take-up member 13a to the first detection member 16a. This moment is also called a tipping point. Figures 10 and 11 are views illustrating the positions of these elements during such a transfer or tilting. During such a disengagement, the first pressure plate 3a is moved away from the reaction plate 4 by means of the corresponding return tabs 8a, so as to release the first friction disc 5a.

As illustrated in FIG. 10, when the first diaphragm 9a is in the fully disengaged position, it completely releases the first take-up member 13a. In this position, the first detection member 16a is kept fixed in rotation by pinching between the first diaphragm 9a and the fixed cover 6. In this position, the pressing member 20a is supported on the detection member 16a. Furthermore, the head 23a of the abutment pad 21a is spaced from the radial surface 7b of the movable cover 7 and the second end of the movable tongue 20a is spaced by a play j2 relative to the corresponding secondary end of the first member of catch-up 13a.

The first take-up member 13a, constrained by the second elastic member 19a, is therefore driven in rotation as illustrated in FIG. 11, so as to fill all or part of the clearance j2 between said first take-up member 13a and the tongue 20a.

The pivoting of the first take-up member 13a and of the first detection member 16a with respect to the fixed cover 6 makes it possible, via the ramps 14a, 17a and the counter-ramps 15a, 15'a, to increase the axial distance between the fixed cover 6 and the support zone of the first diaphragm 9a on said members 13a, 16a, which allows to gradually compensate for the wear of the linings of the first friction disc 5a and / or the wear of the counter materials of the first pressure plate 3a and reaction plate 4.

Such a structure also makes it possible to maintain the initial axial position of the stop.

As the operation progresses, the end 16’a shifts axially with respect to the end 13’a, generating grip or loss of angle of the diaphragm 9a.

FIG. 12 illustrates an alternative embodiment in which the counter-ramp 15’a is formed directly on the fixed cover, and in which the counter-ramp 15a is formed on a spacer 24, integral with the fixed cover 6.

In all cases, according to the invention, the inclination of the ramp 14a of the take-up member 13a relative to the radial plane is different from the inclination of the ramp 17a of the detection member 16a relative to the plane radial. The inclination of the counter-ramp 15a and the inclination of the counter-ramp 15’a may be different.

In particular, the inclination of the ramp 17a of the detection member 16a relative to the radial plane is defined, at more or less 5%, by the following relation:

in which: - CDRest the inclination of the ramp 17a of the detection member 16a relative to the radial plane (in mm / °) - CMRest the inclination of the ramp 14a of the take-up member 13a relative to the plane radial (in mm / °), RBUtée is Ιθ distance between the support of the clutch bearing on the fingers 9 ”a of the diaphragm 9a and the axis of rotation X (in mm), - ÆDAest the distance between support of the detection member 16a on the diaphragm 9a and the axis of rotation X (in mm), - Rmr is the distance between the support of the take-up member 13a on the diaphragm 9a and the axis of rotation X (in mm), - kdiaph is the stiffness constant of the fingers 9 ”a of the diaphragm 9a (in N / mm), - Load, is the axial force generated by the stop on the diaphragm 9a (in N), - QMR is the rotation of the take-up member 13a with respect to the axis of rotation X.

The above relationship makes it possible to calculate the theoretical value of the inclination of the ramp 17a of the detection member 16a relative to the radial plane as a function of the other characteristics of the device. This relationship is applicable to the ramps 14a, 17a and the counter-ramps 15a, 15’a, as indicated above. Actual tilt may vary in

a certain measure with respect to the theoretical inclination, so as to take into account in particular the deformation of the parts and / or the dimensional or mounting tolerances. The inclination of the ramp 14a of the take-up member 13a relative to the radial plane is for example between 0.005 and 0.3 mm / °, the inclination of the ramp 17a of the detection member 16a relative to the radial plane being for example between 0.004 and 0.5 mm / °. According to an example of implementation, the inclination is measured by rotating the ramp by an angle in degrees and by measuring the difference in height in mm from the end 13'a, 16'a of the ramp before and after the rotation of said ramp.

Of course, the inclinations of the counter-ramps 15a and 15’a are adapted accordingly.

Each counter-ramp 15a, 15'a has a first circumferential end 25 and a second circumferential end 26 (FIG. 5), the counter-ramps 15a, 15'a being able to cross, that is to say being located at the same height or at the same axial position, at the first circumferential end 25 (as illustrated in FIG. 5), at the second circumferential end 26, or at a midpoint, located between said first and second circumferential ends 25 , 26.

The production of two ramps 14a, 17a and two counter-ramps 15a, 15'a of different inclination relative to each other makes it possible to adjust the axial position of the radially internal periphery of the diaphragm 9a at the time of tilting of the 'support of the diaphragm 9a on the take-up 13a and detection 16a, so that said position does not vary or almost not as the wear of the friction disc 5a is caught.

FIG. 13 illustrates a device which is not the subject of the invention.

In particular, FIG. 13 illustrates in particular the position of the first diaphragm 9a and of the ends 13'a, 16'a of the take-up 13a and detection 16a members, in the event of absence of wear (dotted lines) and in the event of 'wear (solid lines). It can be seen that the axial position of the radially internal periphery of the fingers 9 "a of the diaphragm 9a at the tilting point varies by a distance d depending on the wear. In other words, the race of the clutch bearing bearing on said internal periphery must be able to vary as a function of wear so as to reach the tipping point, that is to say the point where the diaphragm 9a transfers its support from the end 13'a of the take-up member 13a to the end 16'a of the detection member 16a, or vice versa. This tends to increase the travel of the clutch bearing by the value of the distance d, and therefore the axial size of the device. This also has a negative effect on the steering and operation of the double clutch.

FIG. 14 illustrates a device which is the subject of the present invention.

As can be seen in FIG. 14, the differences in inclination of the ramps 14a, 17a between the take-up member 13a and the detection member 16a makes it possible to vary the axial distance between the ends 13'a and 16'a , as they wear out, so that the bearing area of the clutch bearing on the radially inner periphery of the fingers 9 ”has diaphragm 9a at the tipping point does not vary or almost does not vary with the 'wear. In other words, the aforementioned distance is reduced or even canceled. The stroke of the clutch bearing as well as the axial size of the double clutch 1 are thus reduced.

In order to compensate for the wear of the second friction disc 5b, the second pressure plate 3b and / or the reaction plate 4, the second clutch 2b is equipped with second means for catching up and detecting wear.

The second take-up and wear detection means equipping the second clutch 2b are inserted axially between the second diaphragm 9b and the second pressure plate 3b.

The second take-up and wear detection means comprise a second movable take-up member 13b in the form of a ring comprising an end against which the second diaphragm 9b is capable of coming to bear, and one end comprising at least a ramp extending circumferentially, cooperating with an associated counter-ramp formed for example directly on the second pressure plate 3b.

The second take-up and wear detection means also comprise a second movable detection member 16b in the form of a ring comprising an end against which the second diaphragm 9b is capable of coming to bear, and one end comprising at at least one ramp extending circumferentially, cooperating with a counter-ramp of the second pressure plate 3b.

The two movable members 13b, 16b are concentric and separated from each other for example by centering and spacing pads. In the embodiment shown in the figures, the second movable detection member 16b is located radially outside the corresponding second movable take-up member 13b. Alternatively, the respective positions of said movable members 13b, 16b can be reversed.

The inclinations of the ramps and counter-ramps can be identical.

A first tension spring 18b extending circumferentially is mounted between the second detection member 16b and the second pressure plate 3b.

A second spring, such as a pin-shaped spring, is mounted between the second detection member 16b and the second take-up member 13b.

The length of the first spring 18b is large, so as to be able to request the displacement of the second detection member 16b over a large angular range (for example between 30 ° and 120 °).

The second clutch 2b also includes at least a second pressing member in the form of an elastic tongue exerting an axial force. Said tongue is fixed to the pressure plate 3b, at a first end, and comes to bear, at a second end, on the corresponding secondary end of the second detection member 16b and possibly on the second wear take-up member 13b, so as to force it to bear on the second pressure plate 3b. Thus, in particular, there may be an axial clearance between the second pressing member and the corresponding secondary end of the second wear take-up member 13b, even though the second pressing member 20b is in contact with the secondary end. correspondent of the second detection member 16b.

As before, an abutment stud is fixed on the second end of said tongue. The stop stud has in particular a first end fixed to the tongue and a second cylindrical end forming an enlarged head. The stud passes through a hole in the fixed cover 6 and is capable of coming to bear on the radial surface 6c of the fixed cover 6.

In particular, the enlarged head of the abutment pad is intended to come to bear on the corresponding radial surface 6c when the displacement of the second pressure plate 3b is significant, that is to say when there is wear of the linings of the second friction disc 5b and / or counter-materials of the second pressure plate 3b and of the reaction plate 4.

It should be noted that the invention is also applicable to simple clutches of the normally closed type. The invention is also applicable to clutches of the normally open type, in particular for hybrid applications.

Figures 15 and 16 are views corresponding to Figures 13 and 14, illustrating a clutch device 1 of the single clutch type. In particular, FIG. 15 illustrates a device which is not the subject of the invention while FIG. 16 illustrates a device which is the subject of the invention.

In both cases, the device comprises, as previously, a cover 6 coupled in rotation to the reaction plate 4, a pressure plate 3 movable between a engaged position in which it encloses a friction disc 5 with the reaction plate 4, and a disengaged position. The pressure plate 3 is actuated by a diaphragm 9 bearing on the pressure plate 3, in a support zone 27, and capable of bearing on the ends 13 'and 16' of a take-up member 13 and d 'a detection member 16. The counter-ramp 15 or the counter-ramp 15' are formed on the cover 6. As before, at least one of the counter-ramps 15, 15 'can be formed on a spacer mounted on cover 6.

The take-up 13 and detection 16 members are located radially inside the support zone 27 of the diaphragm 9 on the pressure plate 3.

In particular, FIG. 15 illustrates in particular the position of the diaphragm 9 and of the ends 13 ′, 16 ′ of the take-up 13 and detection 16 members, in the event of absence of wear (dotted lines) and in the event of wear ( solid lines) in the context of a simple clutch according to the prior art. As before, it can be seen that the axial position of the radially inner periphery of the fingers 9 "of the diaphragm 9 at the tilting point varies by a distance d depending on the wear. In other words, the race of the clutch bearing bearing on said internal periphery also varies by the value of the distance d as a function of wear.

As can be seen in FIG. 16 (where the invention is adapted to a normally closed single clutch mechanism, the mechanism being of the pushed type), the differences in inclination of the ramps 14, 17 between the take-up member 13 and the detection member 16 makes it possible to vary the axial distance between the ends 13 ′ and 16 ′, as they wear out, so that the bearing zone of the clutch bearing on the periphery radially internal of the 9 ”fingers of the diaphragm 9 at the tipping point does not vary or hardly varies with wear. In other words, the aforementioned distance is reduced or even canceled. The stroke of the clutch bearing as well as the axial size of the clutch device 1 are thus reduced.

Claims (14)

1. Clutch device (1) with wear compensation, in particular for a motor vehicle, comprising: - a reaction plate (4) intended to be coupled in rotation to a driving shaft, around an axis of rotation (X ), - a friction disc (5a, 5), intended to be coupled to a driven shaft, - a pressure plate (3a, 3) actuated by a diaphragm (9a, 9) so as to tighten or release the friction disc (5a, 5) on the reaction plate (4), - a cover (6), - means for detecting and taking up wear, capable of taking up the wear of the friction disc (5a, 5), wear detection and take-up means being mounted between the diaphragm (9a, 9) and the cover (6) and comprising: wear take-up means interposed between the diaphragm (9a, 9) and the cover (6) , said wear take-up means comprising at least one take-up member (13a, 13) movable within a determined range and comprising a ramp (14a, 14) cooperated ant with a counter ramp (15a, 15) integral with the cover (6), so as to adjust the distance between the diaphragm (9a, 9) and the cover (6) and compensate for the corresponding wear as a function of the position of the ramp (14a, 14) relative to the counter-ramp (15a, 15), means for detecting wear capable of authorizing the movement of said take-up member (13a, 13) in the event of wear and capable of prevent such displacement when this wear is not sufficient, said detection means comprising at least one detection member (16a, 16) movable, within a determined range, relative to the take-up member (13a, 13) and comprising a ramp (17a, 17) cooperating with a counter-ramp (15'a, 15 ') integral with the cover (6), the inclination of the counter-ramp (15a, 15) cooperating with the take-up member ( 13a, 13) is different from the inclination of the counter-ramp (15'a, 15 ') cooperating with the detection member (16a, 16). 2. Device (1) according to claim 1, characterized in that the inclination of the ramp (14a, 14) of the movable take-up member (13a, 13) is different from the inclination of the ramp (17a, 17) of the detection member (16a, 16). 3. Device (1) according to claim 1 or 2, characterized in that it comprises at least one pressing member (20a) constraining at least the ramp (17a, 17) of the detection member (16a, 16) against the associated counter-ramp (15'a, 15 '), the pressing member (20a) being able to cooperate with a fixed stop (7b) so as to release the detection member (16a, 16) when a wear is detected, the take-up member (13a, 13) being urged so as to move when said take-up member (13a, 13) is released by the diaphragm (9a, 9), the detection member (16a, 16) being urged so as to move and catch up, at least in part, the clearance (j1) between the latter and the pressing member (20a), when said detection member (16a, 16) is released by the pressing member (20a) and through the diaphragm (9a, 9). 4. Device (1) according to one of claims 1 to 3, characterized in that the take-up member (13a, 13) and the detection member (16a, 16) are annular, coaxial, and are capable of pivot around the axis of rotation (X), the inclination of the counter-ramp (15'a, 15 ') cooperating with the detection member (16a, 16) relative to the radial plane being defined, more or less 5%, by the following relationship: in which: - CDR is the inclination of the counter ramp (15’a, 15 ’) cooperating with the detection member (16a, 16) relative to the radial plane, in mm / °, - CMR is the inclination of the counter-ramp (15a, 15) cooperating with the take-up member (13a, 13) relative to the radial plane, in mm / °, RBUtée is 'at a distance between the support of' a clutch stop on the fingers (9 ”a, 9”) of the diaphragm (9a, 9) and the axis of rotation (X), in mm, - Rdr is the distance between the support of the detection (16a, 16) on the diaphragm (9a, 9) and the axis of rotation (X), in mm, - Rmr is the distance between the support of the take-up member (13a, 13) on the diaphragm (9a, 9) and the axis of rotation (X), in mm, - kdiaph is the stiffness constant of the fingers (9 ”a, 9”) of the diaphragm (9), in N / mm, - Load ,, is the axial force generated by the stop on the diaphragm (in N), - ΘΜΚ is the rotation of the take-up member (13a, 13) relative to the axis of rotation (X). 5. Device (1) according to one of claims 2 to 4, characterized in that the take-up member (13a, 13) and the detection member (16a, 16) are annular, coaxial, and are capable of pivot around the axis of rotation (X), the inclination of the ramp (17a, 17) of the detection member (16a, 16) relative to the radial plane being defined, more or less 5%, by the following relationship: in which: - C „„ is the inclination of the ramp (17a, 17) of the detection member (16a, 16) relative to the radial plane, in mm / °, - CMR is the inclination of the ramp (14a, 14) of the take-up member (13a, 13) relative to the radial plane, in mm / °, RBUtée is' at a distance between the support of a clutch bearing on the fingers (9 ”a , 9 ”) of the diaphragm (9a, 9) and the axis of rotation (X), in mm, - Rdr is the distance between the support of the detection device (16a, 16) on the diaphragm (9a, 9) and the axis of rotation (X), in mm, - Rmr is the distance between the support of the take-up member (13a, 13) on the diaphragm (9a, 9) and the axis of rotation (X), in mm, - kdiaph is the stiffness constant of the fingers (9 ”a, 9”) of the diaphragm (9), in N / mm, - Load ,, is the axial force generated by the stop on the diaphragm (in N), - ΘΜΚ is the rotation of the take-up member (13a, 13) relative to the axis of rotation (X). 6. Device (1) according to one of claims 1 to 5, characterized in that it comprises at least one spacer (24) integral with the cover (6), the ramp (15a, 15) of the take-up member (13a, 13) and / or the ramp (15'a, 15 ') of the detection member (16a, 16) being formed on the spacer (24). 7. Device (1) according to claim 6, characterized in that the spacer (24) is of annular shape. 8. Device (1) according to one of claims 1 to 7, characterized in that the inclination of the ramp (14a, 14) of the take-up member (13a, 13) relative to the radial plane is between 0.005 and 0.3 mm / °, the inclination of the ramp (17a, 17) of the detection member (16a, 16) relative to the radial plane being between 0.004 and 0.5 mm / °. 9. Device (1) according to one of claims 1 to 8, characterized in that the diaphragm (9a, 9) releases the detection member (16a, 16) and prevents the displacement of the take-up member (13a , 13), in the fully engaged position, and in that the diaphragm (9a, 9) releases the take-up member (13a, 13) and prevents the displacement of the detection member (16a, 16), in the fully position disengaged, the diaphragm (9a, 9) always coming to bear on at least one of said members (13a, 13, 16a, 16) between its fully engaged and totally disengaged positions. 10. Device (1) according to one of claims 1 to 9, characterized in that the detection member (16a, 16) has one end (16'a, 16 ') capable of serving to support the diaphragm (9a, 9) and one end comprising at least one ramp (17a, 17), cooperating with the counter-ramp (15'a, 15 ') associated with the cover (6). 11. Device (1) according to one of claims 1 to 10, characterized in that the take-up member (13a, 13) has one end (13'a, 13 ') capable of serving to support the diaphragm (9a, 9) and one end comprising at least one ramp (14a, 14), cooperating with the counter-ramp (15a, 15) associated with the cover (6). 12. Device (1) according to one of claims 3 to 11, characterized in that it comprises a stop member (21a) connected to the pressing member (20a), the stop member (21a) being designed to separate the pressing member (20a) from the detection member (16a, 16) and / or from the take-up member (13a, 13) in the event of wear. 13. Device (1) according to one of claims 3 to 12, characterized in that the pressing member (20a) comprises at least one elastic tongue (20a) one end of which is capable of coming to bear on the member mobile detection (16a, 16) and / or on the corresponding mobile take-up member (13a, 13). 14. Device (1) according to one of claims 1 to 13, characterized in that the counter-ramps (15a, 15'a, 15, 15 ') are locally combined, for example at one of the ends said counter-ramps (15a, 15'a, 15, 15 ') or at a median zone located between said ends.