WO2015180777A1 - Clutch device, in particular for a motor vehicle - Google Patents

Abstract

The invention relates to a clutch device (1) comprising at least one reaction plate intended to be rotatably coupled to a drive shaft, at least one friction disk intended to be coupled to a driven shaft, at least one pressure plate actuated by a diaphragm (7) so as to tighten or release the friction disk on the reaction plate, said diaphragm (7) comprising fingers (12) extending radially toward the inside, a first cover (5), fixed in relation to the reaction plate, the diaphragm (7) being mounted tilting on the first cover (5), by means of rivets (8) extending axially and engaged between the fingers (12) of the diaphragm (7).

Description

 Clutch device, in particular for a motor vehicle

The present invention relates to a clutch device, especially for a motor vehicle, in particular a double clutch.

 The patent application WO 2013/088043 discloses a dual clutch for coupling the shaft of a motor of a vehicle alternately with two coaxial input shafts of a gearbox, which can be robotized.

 Thus, a dual clutch allows to change gears while maintaining the transmission of a torque engine to the vehicle wheels. Indeed, the two clutch mechanisms are associated with odd and even gear ratios, respectively. During a change of gear ratio, a first clutch mechanism is disengaged while the second clutch mechanism is engaged, so that the engine torque is progressively transferred from the first to the second clutch mechanism.

 Each clutch mechanism comprises a diaphragm intended to cooperate with a pressure plate integral in rotation with a cover and the motor shaft. Each diaphragm is movable by means of a corresponding clutch abutment, 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 decoupling of the shafts of the engine and the gearbox and the rest position of the diaphragm corresponds to a decoupling or a coupling of these shafts. These are respectively a normally open clutch and a normally closed clutch.

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

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

 Each friction disk is rotatably connected to an input shaft of the gearbox and each reaction plate is rotatably connected to a flywheel connected to the drive shaft. Thus, the clamping of a friction disk between the corresponding pressure and reaction plates allows the transmission of a torque between the drive shaft and the shaft of the associated gearbox.

 Each diaphragm is in the form of a generally annular elastic sheet having, at its radially inner periphery, fingers extending radially inwards. Each diaphragm is pivotally mounted on the lid, by means of rivets ensuring the retention of the diaphragm while allowing it to tilt.

 The control of each clutch is conventionally done by means of a clutch abutment cooperating with the radially inner periphery of the corresponding diaphragm, that is to say with the free ends of the fingers of said diaphragm. Each diaphragm thus forms a lever transmitting the force applied by the clutch abutment to the corresponding pressure plate.

 The rivets for holding the diaphragms have a first end for attachment to the lid, a second end having a cylindrical head, and a cylindrical central zone located between two fingers of the corresponding diaphragm.

 The head forms a radial shoulder with the cylindrical central zone, this radial shoulder defining a radial annular bearing surface.

In operation, a force is applied by the clutch abutment on the corresponding diaphragm, so that the fingers of the diaphragm do not bear against the abovementioned abutment surfaces of the rivets, both in an engaged state and in a disengaged state of the corresponding clutch mechanism. However, before mounting such a double clutch on a gearbox or during a possible disassembly of such a double clutch, no effort is applied to the inner periphery of the diaphragms. The double clutch is then in a position called transport or storage. In this position, the lateral edges of the fingers of the diaphragms bear against the heads of the rivets, in particular on the aforementioned radial bearing surfaces. The diaphragms are thus held axially by the rivets. However, there are no means for radial retention of the diaphragms, which can then move radially to a certain extent.

 Such offset or misalignment of the diaphragms can be problematic during a subsequent assembly of the double clutch on a gearbox, since the diaphragms can then be off-center with respect to the clutch stops, generating malfunctions, mounting problems and / or or premature wear.

 This disadvantage, presented here in the context of a double-clutch, also arises in the case of a simple clutch, that is to say having a single pressure disc and a single pressure plate.

 The invention aims in particular to provide a simple, effective and economical solution to this problem.

 For this purpose, it proposes a clutch device comprising: at least one reaction plate intended to be coupled in rotation to a driving shaft,

 at least one friction disk intended to be coupled to a driven shaft,

at least one pressure plate actuated by a diaphragm so as to clamp or release the friction disk on the reaction plate, said diaphragm having fingers extending radially inwardly,

 a first lid, fixed with respect to the reaction plate,

the diaphragm being pivotally mounted on the first cover, by means of rivets extending axially and engaged between the fingers of the diaphragm, each rivet comprising a head capable of bearing axially against the lateral edges of the corresponding fingers in a position said storage or transport of said clutch device,

 characterized in that the head of each rivet comprises at least one wall oblique with respect to the radial direction, the corresponding lateral edges of the fingers of the diaphragm being able to bear against said oblique wall.

 The use of such an oblique wall makes it possible to reposition or refocus the diaphragm radially, when the lateral edges of the fingers of the diaphragm bear against said oblique wall, that is to say in the storage or transport position of the diaphragm. device. Thus, during a subsequent assembly of the device on a gearbox, it avoids misalignment and, consequently, any malfunction, mounting problem or premature wear of said device.

 Preferably, the oblique wall is a frustoconical wall.

 Each rivet may comprise a first end fixed to the first cover, a second end comprising the head, and a median zone located between the corresponding fingers of the diaphragm, said central zone being cylindrical.

 In addition, the first cover may define an internal volume in which are housed the reaction plate, the friction disc, the pressure plate and / or the diaphragm.

In addition, the device may comprise: a first and a second friction disc carrying friction linings, intended to be coupled respectively to a first and a second driven shaft,

 a first and a second pressure plate, respectively actuated by a first and a second diaphragm so as to clamp or release the first and second friction disc on the reaction plate, the first pressure plate being fixedly connected to a second lid, movable in translation relative to the reaction plate, and being actuated by pressing the first diaphragm on the second cover,

 rivets being engaged between the fingers of the first diaphragm and / or the second diaphragm, the rivets each comprising a head comprising a wall that is oblique with respect to the radial direction.

 In this case, the device may comprise a single reaction plate disposed axially between the first and second friction discs.

 The invention also relates to a motor vehicle comprising a device of the aforementioned type.

 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 non-limiting example with reference to the accompanying drawings in which:

 FIG. 1 is a perspective view of a clutch device according to the invention,

 FIG. 2 is a view in axial section of the device of FIG. 1,

 FIG. 3 is a detail view in axial section of a part of the device according to the invention,

 FIG. 4 is a sectional view along the line IV-IV of FIG. 3;

- Figure 5 is a view illustrating a rivet of the device according to the invention. Figures 1 to 5 illustrate a clutch device 1 according to one embodiment of the invention, namely a double clutch for coupling a motor with a first and a second input shaft of a gearbox. The double clutch 1 comprises first and second clutch mechanisms allowing the passage of ratios of different parities.

 The first clutch mechanism comprises a first pressure plate 2 and a reaction plate 3 between which a first friction disc 4 extends. The first pressure plate 2 is rotatably coupled to the reaction plate 3 and can be moved in translation by relative to the latter, between an engaged position and a disengaged position, in which it clamps the first friction disc 4 on the reaction plate 3, or releases the first friction disc 4, respectively.

 The reaction plate 3 is fixed on a first cover 5 coupled to the motor shaft. The first friction disc 4 is coupled to the first input shaft of the gearbox. Thus, in the engaged position of the first clutch mechanism, the motor shaft is coupled to the first input shaft of the gearbox.

 The first pressure plate 2 is fixed on a second cover 6, movable in translation relative to the reaction plate 3 and the first cover 5, and extending forwardly.

 A first diaphragm 7 is pivotally mounted on the first cover 5, by means of rivets 8 ensuring the positioning and centering of said diaphragm 7 while allowing it to tilt. The first diaphragm 7 is in the form of an elastic annular plate bearing on the first cover 5 at a bearing zone 9, the first diaphragm 7 tilting around this support zone 9. The zone 9 is formed by a projecting portion of the first cover 5.

The control of the first clutch mechanism is conventionally done by means of a first clutch abutment (no shown) cooperating with the radially inner periphery of the first diaphragm 7. The first diaphragm 7 forms a lever transmitting the force applied by the first clutch abutment to the first pressure plate 2, via the second cover 6. The zone support of the first diaphragm 7 on the second cover is referenced 10 and is located radially outside the bearing zone 9.

 The first clutch mechanism is of the normally open type. The rest position of the first diaphragm 7 thus corresponds to a disengaged state of the first clutch mechanism. The diaphragm 7 preferably has a portion of the Belleville washer type for returning the diaphragm 7 to its rest position.

 In the rest position of the first diaphragm 7, that is to say when the first clutch abutment exerts a slight force on the first diaphragm 7, the first diaphragm 7 thus exerts a zero or low force on the first pressure plate 2. The first pressure plate 2 is separated from the reaction plate 3 by means of appropriate rappelling means, such as resilient tongues January 1, so as to release the first friction disk 4. In said storage position or transport, the first diaphragm 7 is not biased by the first clutch abutment.

 The radially inner periphery of the first diaphragm 7 comprises fingers 12 extending radially inwards, each finger 12 having two lateral edges 13. The first clutch abutment is intended to bear on the radially inner ends of the fingers 12 .

 The rivets 8, for example three in number, are regularly distributed around the circumference and are each arranged between two fingers 12 of the first diaphragm 7.

As best seen in FIGS. 3 to 5, each rivet 8 has a first end 14 fixed to the first cover 5, a second end comprising the head 15, and a central zone 16 located between the corresponding fingers 12 of the diaphragm 7, said median zone 16 being cylindrical.

 The head 15 has a cylindrical end zone 17 and a frustoconical zone 18 connecting the end zone 17 and the central zone 16.

 As indicated above, the use of a frustoconical surface makes it possible to reposition or refocus radially the first diaphragm 7, when the lateral edges 13 of the fingers 12 of the diaphragm 7 come to bear on said oblique wall 18, in the storage position or transport device 1, wherein the first diaphragm 7 is not biased. Thus, during a subsequent assembly of the device 1 on a gearbox, misalignment is avoided and, consequently, any malfunction, mounting problem or premature wear of said device 1.

 It will be noted that, in the rest position, in which the first clutch abutment exerts a slight force on the first diaphragm 7, the fingers 12 of the first diaphragm 7 do not bear against the heads 15 of the rivets 8. therefore only the radial centering function in the storage or transport position of the device 1.

 The angle α between the frustoconical surface of the zone 18 and the axis 19 of the rivet 8 is thus calculated so as to obtain such contact with the fingers 12 of the diaphragm 7 in the transport or storage position, while avoiding such contact when the device 1 is mounted on the gearbox.

The second clutch mechanism comprises a second pressure plate 20 and a second friction disc 21 extending radially between the reaction plate 3 and the second pressure plate 20. The same reaction plate 3 is thus used for both clutch mechanisms, each friction disc 4, 21 being disposed on the side of one of the two radial bearing faces of the reaction plate 3. The second pressure plate 20 is rotatably coupled to the reaction plate 3 and is movable in translation relative thereto, between an engaged position and a disengaged position, in which it squeezes the second disc of friction 21 on the reaction plate 3, or respectively releases the second friction disk 21.

 The second friction disc 21 is coupled to the second input shaft of the gearbox. Thus, in the engaged position of the second clutch mechanism, the motor shaft is coupled to the second input shaft of the gearbox.

 A second diaphragm 22 is pivotally mounted on the first cover 5, by means of rivets 23 (FIG. 2) ensuring the centering of said diaphragm 22 while allowing it to tilt. The second diaphragm 22 is, as before, in the form of an elastic annular sheet bearing on the cover 5 at a bearing zone 24, the second diaphragm 22 thus pivoting around this bearing zone 24 The second diaphragm 22 also bears on the second pressure plate 20, at a bearing zone 25 situated radially inward with respect to the bearing zone 24.

 The control of the second clutch mechanism is conventionally effected by means of a second clutch abutment cooperating with the radially inner periphery of the second diaphragm 22. The second diaphragm 22 forms a lever transmitting the force applied by the second clutch abutment to the second pressure plate 20, to allow effective clamping of the second friction disk 21.

 The second clutch mechanism is also of the normally open type. In the rest position of the second diaphragm 22, that is to say when the second clutch abutment exerts a zero or low force on the second diaphragm 22, the second diaphragm 22 exerts a zero or low force on the second plate of pressure 20. The second pressure plate 20 is spaced from the reaction plate 3 by means of appropriate rappelling means, such as elastic tongues 26 (Figure 1), so as to release the second friction disk 21.

Claims

1. Clutch device (1) comprising:  at least one reaction plate (3) intended to be coupled in rotation to a driving shaft,  at least one friction disk (4, 21) intended to be coupled to a driven shaft,  at least one pressure plate (2, 20) actuated by a diaphragm (7, 22) so as to clamp or release the friction disc (4, 21) on the reaction plate (3), said diaphragm (7, 22) having fingers (12) extending radially inwardly,  a first cover (5) fixed with respect to the reaction plate (3),  - the diaphragm (7) being pivotally mounted on the first cover (5), by means of rivets (8) extending axially and engaged between the fingers (12) of the diaphragm (7), each rivet (8) comprising a head (15) adapted to bear axially on the lateral edges (13) of the corresponding fingers (12) in a so-called storage or transport position of said clutch device (1),  characterized in that the head (15) of each rivet (8) has at least one oblique wall (18) with respect to the radial direction, the corresponding lateral edges (13) of the fingers (12) of the diaphragm (7) being suitable to bear against said oblique wall (18).  2. Clutch device according to claim 1, characterized in that the oblique wall is a frustoconical wall (18). 3. Device according to claim 1 or 2, characterized in that each rivet (8) has a first end (14) fixed to the first cover (5), a second end comprising the head (15), and a central zone (16). ) located between the corresponding fingers (12) of the diaphragm (7), said central region (16) being cylindrical. 4. Device according to one of claims 1 to 3, characterized in that the first cover (5) defines an internal volume in which are housed the reaction plate (3), the friction disc (4, 21), the pressure plate (2, 20) and / or the diaphragm (7, 22).  5. Device according to one of claims 1 to 4, characterized in that it comprises:  a first and a second friction disk (4, 21) carrying friction linings, intended to be coupled respectively to a first and a second driven shaft,  a first and a second pressure plate (2, 20), respectively actuated by a first and a second diaphragm (7, 22) so as to clamp or release the first and second friction disc (4, 21) on the reaction plate (3), the first pressure plate (2) being fixedly connected to a second lid (6) movable in translation relative to the reaction plate (3) and being actuated by pressing the first diaphragm (7) on the second cover (6),  rivets (8) being engaged between the fingers (12) of the first diaphragm (7) and / or the second diaphragm (22), said rivets (8) each comprising a head (15) comprising an oblique wall (18) for each relative to the radial direction.  6. Device according to claim 5, characterized in that it comprises a single reaction plate (3) disposed axially between the first and second friction discs (4, 21).  7. Motor vehicle comprising a device (1) according to one of claims 1 to 6.