WO2018020118A1

WO2018020118A1 - Assembly for a clutch device, in particular for a motor vehicle

Info

Publication number: WO2018020118A1
Application number: PCT/FR2017/052032
Authority: WO
Inventors: Olivier Marechal; Nicolas Deliencourt; Julien Brailly
Original assignee: Valeo Embrayages
Priority date: 2016-07-25
Filing date: 2017-07-24
Publication date: 2018-02-01
Also published as: FR3054275B1; KR102470316B1; KR20190034251A; FR3054275A1

Abstract

The invention relates to an assembly (1) for a clutch device, in particular for a motor vehicle, comprising a cover (2) having an axis (X), a pressure plate (9) that can move relative to the cover (2) along said axis (X) and is activated by a diaphragm (10) axially interposed between the cover (2) and the pressure plate (9), the diaphragm (10) being movable between an engaged position and a disengaged position, a resiliently deformable assist washer (30), axially interposed between the cover (2) and the diaphragm (10) and capable of exerting a variable axial force as a function of the position of the diaphragm (10), characterised in that the assist washer (30) bears against the diaphragm (10) by means of an intermediate member (33) made of synthetic material.

Description

Assembly for a clutch device, especially for a motor vehicle

The present invention relates to an assembly for a clutch device, particularly for a motor vehicle.

In a motor vehicle, a clutch device is designed to couple in rotation a motor shaft, such as for example a crankshaft, and an input shaft of a gearbox.

The clutch device usually comprises a cover in which is housed an annular diaphragm pivoting between an engaged position and a disengaged position so as to move a pressure plate. The diaphragm pivots about first and second circumferentially extending bearing regions respectively on either side of the diaphragm, respectively between the diaphragm and the cover and between the diaphragm and the pressure plate. The lid, the diaphragm and the pressure plate are integral in rotation.

The annular diaphragm thus forms an articulated lever and has at its radially inner periphery radial fingers cooperating with a clutch abutment whose axial displacement causes the tilting of the diaphragm between its engaged and disengaged positions. The outer periphery of the diaphragm allows it to move the pressure plate. The clutch release is operated by the user using the clutch pedal.

The pressure plate, urged by the diaphragm, is for clamping a friction disc on a reaction plate coaxial with the pressure plate and the friction disk.

The friction disc is rotatably connected to the input shaft of the gearbox and the reaction plate is rotatably connected to the cover and a flywheel connected to the drive shaft. Thus, the clamping of a friction disk between the pressure and reaction plates allows the transmission of a torque between the motor shaft and the input shaft of the gearbox.

The use of the clutch causes wear friction friction linings as well as counter-materials of the pressure plates and associated reaction. This results in a variation of the position of the pressure plate relative to the diaphragm and / or the associated reaction plate, generating a variation of the friction disk clamping force and / or a modification of the licking point and the stroke of the clutch stop. It is recalled that the licking point is the position from which a portion of the engine torque is transmitted to the shaft of the gearbox when closing the clutch.

FIG. 1 represents the variation of the load F of the diaphragm measured at the abutment, that is to say the variation of the axial force to be exerted by the clutch abutment to actuate the diaphragm, along the axis of said stop, as a function of the axial displacement D of the abutment, respectively for zero wear (curve C0), for wear equal to 50% of the maximum permissible wear (curve C1), and for the maximum permissible wear (curve C2).

On each of said curves, the engaged position is represented by an abscissa or a displacement D equal to D0, D1 and D2 respectively, the disengaged position in case of zero wear being represented by an abscissa or a displacement D equal to D3. In case of wear, the point D3 shifts in the same way that the points D1 and D2 are offset with respect to D0, the stroke of the clutch abutment being fixed. This, however, has not been shown to facilitate the reading of the figure.

It can be seen that, for each of the curves, the load of the diaphragm measured at the stop gradually increases during the disengaging phase, until reaching a maximum load (for a displacement Dmax), before gradually decreasing to the position disengaged. It is also noted that the maximum load of the diaphragm increases with wear.

However, the load of the diaphragm measured at the stop is related to the force exerted by the user on the clutch pedal. In other words, the effort that a user must exert on the pedal to disengage will be more important than the wear is important.

To ensure the comfort of the user, it is necessary to limit to a certain value the effort to be applied on the pedal.

In order to compensate for the wear, the document FR 2 847 626, in the name of the Applicant, proposes means of catching wear interposed between the pressure plate and the diaphragm. These wear-compensating means comprise a ring with circumferential ramps which cooperate with counter-ramps complementary to the pressure plate. The ramp ring also serves to support the diaphragm so that the rotation of the ring relative to the pressure plate causes the ramps to move relative to the counter-ramps and thus the axial displacement of the pressure plate. relative to the diaphragm, lid and reaction plate. The distance between the pressure plate and the associated reaction plate is thus varied in a way that offsets the wear.

A toothed member is also fixed on the ramp ring and meshes with a worm mounted in a support, also called cassette, attached to the cover, the toothed member being at right of the worm.

The worm is coupled in rotation with a ratchet wheel cooperating with a pawl fixed on the cover and actuated by the diaphragm.

In this way, in case of wear and during successive actuations of the diaphragm, the pawl causes rotation of the ratchet wheel and the worm, the latter causing rotation of the ring carrying the ramps, by the intermediate of the toothed organ. This progressively increases the distance between the pressure plate and the cover and the distance between the pressure plate and the associated reaction plate is progressively reduced so as to compensate for the wear.

Such wear compensating means are relatively complex and expensive.

In order to compensate for the influence of wear on the load of the diaphragm at the stop, it is also known to provide a support washer, mounted axially between the cover and the diaphragm, the support washer exerting an axial force opposing, in part, that exerted by the diaphragm, so as to reduce the maximum effort to exert on the clutch abutment.

FIG. 2 is a diagram similar to that of FIG. 1, in which the variation of the load at the stop F 'as a function of the axial displacement D' of the abutment takes account of the force exerted by the support washer. The corresponding curves are referenced C'O (zero wear), C'1 (wear at 50%) and C'2 (maximum wear).

It is found that the assistance washer is defined so that the curves C'1 and C'2 each comprise a clipped portion E to reduce the maximum force F'max to provide at the stop in case of wear .

The assistance washer thus reduces the effort to be exerted by the user on the clutch pedal, especially in case of wear of the friction disc.

The use of such an assistance washer is in particular known from US 4,602,708.

On such a device comprising an assistance washer, the latter may generate friction increasing the hysteresis of the clutch mechanism, and thus reduce the beneficial effect of the assistance washer, or damage the assistance washer to level of the area of contact with the diaphragm.

The invention aims to remedy this drawback in a simple, effective and inexpensive way. For this purpose, it proposes an assembly for a clutch device, particularly for a motor vehicle, comprising a cover having an axis, a pressure plate movable relative to the cover along said axis and actuated by a diaphragm interposed axially between the cover and the pressure plate, the diaphragm being movable between the engaged position and a disengaged position, an elastically deformable assistance washer, interposed axially between the cover and the diaphragm and capable of exerting a variable axial force as a function of the position of the diaphragm, characterized in that the assistant washer is supported on the diaphragm by means of an intermediate member made of synthetic material.

The present of an intermediate member of synthetic material makes it possible to limit the friction between the assistance washer and the diaphragm and thus avoid any degradation of the diaphragm or the assistance washer.

The synthetic material may be a polymer, for example a polyamide.

The intermediate member may be a ring-shaped washer.

The assistance washer is for example a conical washer, in particular Belleville washer type.

The intermediate member may comprise latching means adapted to snap onto the diaphragm.

In this way, it is possible to form a subassembly to facilitate assembly.

The diaphragm may include an annular portion and fingers extending radially inwardly from the annular portion, the detent means having tabs snap-fitted between the fingers of the diaphragm.

The intermediate member may comprise latching means adapted to snap onto the cover. In this way, it is possible to form a subassembly formed by the intermediate member, the cover, and the support washer located axially between the intermediate member and the cover.

In this case, the lid may comprise an annular radial portion, the latching means comprising tabs snapping on the radially inner periphery of the annular radial portion of the lid.

The intermediate member may comprise latching means adapted to snap onto the assistance washer.

In this case, the latching means may comprise lugs which snap onto the radially inner or outer periphery of the assistance washer.

The latching means may comprise at least three tabs distributed around the circumference, so as to ensure the centering of the assistance washer on the diaphragm.

The intermediate member may be overmoulded on said support washer, so as to be integral with said support washer.

The radially inner periphery of the support washer may be supported on the intermediate member, the radially outer periphery of the support washer being supported on the lid.

The radially outer periphery of the support washer may comprise lugs extending radially outwards, said lugs being supported on the lid.

The intermediate member may be made by injection molding of polymer-type material, or by an additive manufacturing method such as three-dimensional printing.

The assembly according to the invention may also comprise one or more of the following characteristics:

- The assistance washer is mounted axially prestressed between the diaphragm, on the one hand, and the lid, on the other hand, the assembly comprises at least three spacers distributed on the circumference and fixed to the cover, the diaphragm being able to bear on the spacers so as to pivot when the diaphragm is actuated between the engaged and disengaged positions,

each spacer comprises an axial bearing zone, for example a surface extending tangentially, a radial bearing zone, for example an axially extending surface, the diaphragm being able to bear on said bearing zones; axial and tangential so as to ensure the centering and the axial retention of the diaphragm with respect to the cover,

the support zones of each spacer are formed by plane and / or curved surfaces, that is to say convex, for example,

the assembly comprises support members fixed on the cover, each support member comprising a branch resting on the diaphragm and tending to hold the diaphragm in abutment on the cover,

each support member has a general U shape and comprises two branches connected by an elastically deformable part and mounted axially on either side of an edge of the diaphragm, for example a radially inner edge of the diaphragm,

one of the branches of the U-shaped support member is fixed to the cover, for example by riveting,

one of the branches of the U is fixed to the lid by means of a rivet, the other leg of the U has an opening facing the head of the rivet, able to accommodate at least part of said rivet head,

the spacer comprises a first end fixed to the cover and a second end passing through an opening of the diaphragm, for example an opening delimited between two fingers of the diaphragm, said second end including a shoulder defining an axial bearing zone and an area of radial support suitable for position the diaphragm axially and / or radially with respect to the cover,

the assistance washer is designed so that its maximum axial compression between its engaged and disengaged positions is between 0 and 4 mm,

- The pressure plate is rotatably coupled to the lid by means of resilient tongues, axially deformable and tending to bring the pressure plate of the lid,

the cover comprises a radial portion comprising the radially inner peripheral edge and a radially outer peripheral edge which is extended by an axially extending annular portion,

the diaphragm, the assistance washer and / or the pressure plate are housed, at least in part, in the internal volume delimited by the cover,

the radial part of the cover comprises zones of support of the diaphragm,

said support zones of the cover are formed by projecting zones or bosses regularly distributed over the circumference;

said bosses or protruding zones have arcuate shapes and are circumferentially spaced apart from one another.

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 diagram showing the load of the diaphragm at the stop, as a function of the displacement of the stop, for different levels of wear,

FIG. 2 is a diagram showing the load of the thrust washer, as a function of the displacement of the stop, - Figures 3 to 8 show an assembly for a clutch device, according to a first embodiment of the invention, in particular,

FIG. 3 is an exploded perspective view of the assembly; FIG. 4 is a front view of the assembly;

FIG. 5 is a view in axial section of the assembly, along the line V-V of FIG. 4;

FIG. 6 is a detail view in axial section of the assembly, along the line VI-VI of FIG. 4;

FIGS. 7 and 8 are perspective views of the intermediate member and the assistance washer,

FIGS. 9 to 11 represent an assembly for a clutch device, according to a second embodiment of the invention, in particular,

FIG. 9 is a perspective view of the assembly,

FIGS. 10 and 11 are perspective views of the intermediate member and the assistance washer,

FIGS. 12 and 13 are perspective views of the intermediate member and the assistance ring fitted to an assembly for a clutch device, according to a third embodiment of the invention,

- Figures 14 and 15 are perspective views of the intermediate member and the support washer fitted to an assembly for a clutch device, according to a fourth embodiment of the invention.

Figures 3 to 8 show an assembly 1 for a clutch device of normally closed type, according to a first embodiment. This set 1 comprises an annular cover 2, of axis X.

The terms "axial", "radial" and "circumferential" are defined by reference to the X axis. The cover 2 has a radial portion 3 having a radially inner peripheral edge 4 and whose outer peripheral edge is extended by an annular portion 5 extending axially. The lid 2 thus has a general bell shape delimiting an internal volume. The free end of the axial annular portion 5 comprises flanges 6 extending radially outwardly, serving in particular for mounting the cover 2 on a reaction plate formed for example by a flywheel.

The radial portion 3 of the cover 2 has protruding bearing areas 7, arc-shaped in front view, uniformly distributed over the entire circumference and angularly offset from each other.

The assembly 1 further comprises a pressure plate 9 movable axially with respect to the lid 2 and actuated by a diaphragm 10 interposed axially between the lid 2 and the pressure plate 9.

The pressure plate 9 is coupled in rotation to the lid 2 by means of tongues 1 1 extending circumferentially and deformable in the axial direction, so as to return the lid 2 towards the radial portion 3 of the lid 2.

The pressure plate 9 is movable between an engaged position, in which it is displaced by the diaphragm 10 away from the radial portion 3 of the cover 2, so as to clamp a friction disk against the reaction plate, and a disengaged position in which it is recalled towards the radial portion 3 of the cover 2 by the tongues January 1.

The diaphragm 10 includes an annular portion 12 of X axis, radially external and elastically deformable along the X axis, said annular portion 12 being generally conical in the manner of a Belleville washer. The diaphragm 10 further comprises fingers 13 extending radially inwardly from the annular portion 12, the ends free fingers 13 for supporting a clutch abutment not shown. The fingers 13 delimit between them radial slots 14, the radially outer ends of the slots 14 having openings 15, 16 wider than the rest of the slots 14, for example openings of generally square or rectangular shape.

The openings 15, 16 may have different geometries. In the embodiment shown here, the openings 15 are larger than the openings 16.

The annular portion 12 of the diaphragm 10 is supported on the bearing areas 7 of the cover 2, so that the diaphragm 10 can tilt around said support zones 7 when actuated between its engaged and disengaged positions. The annular portion 12 of the diaphragm 10 is also supported on the movable pressure plate 9, in an area 17 located radially outside the bearing areas 7 of the cover 2, so as to form a lever arm.

The assembly 1 further comprises support members 18 in the general shape of C, having a first branch 19 and a second branch 20 connected by a curved zone 21 elastically deformable. The branches 19, 20 are mounted axially on either side of the inner edge of the diaphragm 10. The branch 19 of each support member 18 is fixed to the cover 2 by means of a rivet 22, the branch 20 comprising an opening 23 housing, at least in part, the corresponding head of the rivet 22. The branch 20 tends to press the diaphragm 9 bearing on the bearing areas 7 of the cover 2.

The support members 18 pass through the openings 15 of the diaphragm 9 and make it possible to hold the diaphragm 9 axially and radially in position.

The assembly 1 further comprises spacers 24, for example three spacers 24 uniformly distributed over the circumference. Each spacer 24 passes through an opening 15 of the diaphragm 10. Each spacer 24 has a first end 25 fixed by riveting for example the lid 2, and an end 26 having a shoulder 27 radially external.

As best seen in FIG. 3, the radially outer shoulder 27 defines a flat surface 28 extending radially and forming an axial bearing zone capable of axially positioning the diaphragm 10 with respect to the lid 2. Each external shoulder 27 also defines a planar, cylindrical 29 or curved surface extending axially.

The centering of the diaphragm 10 relative to the cover is achieved by pressing the lateral edges of the openings 15 on the corresponding zones of the spacers 24. A support washer 30 is mounted axially between the cover 2 and the diaphragm 10. The assistance washer 30 is elastically deformable in the axial direction, said support washer 30 having a deformable annular portion 31 of generally conical shape, in the manner of a Belleville washer. Tabs 32 extend radially outwardly from the annular portion 31, said tabs 32 forming rounded areas serving to axially support said washer 30 on the radial portion 3 of the lid 2.

The tabs 32 of the assistance washer 30 are thus in direct abutment on the radial portion 3 of the cover 2.

The radially outer periphery of the annular portion 31 of the support washer 30 bears on the diaphragm 9, via a washer 33 of synthetic material. The assistance washer 30 is mounted prestressed between the lid 2, on the one hand, and the intermediate washer 33, on the other hand.

The intermediate washer 33 has complex geometric shapes obtained by injection molding of synthetic material, for example polyamide.

In particular, said washer 33 has an annular portion 34 from which lugs 35 extend axially towards the diaphragm 10. The lugs 35 are for example at least three in number and are evenly distributed around the circumference. Each tab 35 comprises two axial portions 36 which are elastically deformable, slightly spaced apart in the circumferential direction, and able to be brought closer elastically to one another, the free end of each part 36 comprising a catch hook 37. Said hooks 37 are turned away from each other. Each tab 35 is intended to be inserted into a slot 14 of the diaphragm 10 at a radially central zone of the fingers 13, by bringing the two parts 36 of each tab 35 closer together, the tabs 35 being intended to snap together. on the edges of the corresponding fingers 14 by spacing the two parts 36 and stop the hooks 37 on said edges of the fingers 14.

The tabs 35 thus make it possible to link the intermediate washer 33 to the diaphragm 10, so as to form a pre-assembled subassembly or module, the tabs 35 also ensuring the centering of the intermediate washer 33 with respect to the diaphragm 10. This facilitates assembly. from the whole. Furthermore, this prevents any movement of the intermediate washer 33 so as to avoid noisy phenomena and premature wear of the assembly.

The proper centering of the assistance washer 30 also makes it possible to obtain a uniform distribution of the axial force that it exerts on the diaphragm 10.

The assistance washer 30, the intermediate washer 33, the diaphragm 10 and the pressure plate 9 are housed, at least in part, in the internal volume of the lid 2.

In operation, during a disengagement phase, the user presses on the clutch pedal, so as to move the clutch abutment and thus tilt the diaphragm 10 around the zones 7 of the cover 2, from its engaged position in its disengaged position. The diaphragm 10 pushes the pressure plate 9 against the axial force exerted by the elastic tongues January 1, so as to pinch the friction disk between the pressure plate 9 and the reaction plate. During its tilting, the diaphragm 10 is held in abutment on the cover 2 by the support members 18 and is held in abutment on the radially outer shoulders 27 of the spacers 24. Furthermore, the assistance washer 30 is held in abutment on the cover 2, by the diaphragm 10, whatever the engaged or disengaged position of the diaphragm 10.

The axial crushing of the assistance washer 30 in the engaged position is even more important than the wear u is important. The assist washer 30 is designed to allow a maximum axial compression of between 0 and 4 mm, for example.

As before, the assistance washer 30 is designed so that the axial force to be applied at the clutch abutment (or the radially inner periphery of the fingers 13 of the diaphragm 10) to compress the washer assistance 30, referred to as the load on the abutment of the assist washer 30, varies as a function of the displacement of said clutch abutment.

Furthermore, as previously, the diaphragm 10 and the assistance washer 30 are designed so that the total load at the stop, that is to say the effort to be provided at the clutch abutment to disengage, has a clipped portion E to reduce the maximum force to be provided at the stop in case of wear of the friction disc linings, as shown in Figure 2.

Figures 9 to 1 1 illustrate an assembly according to a second embodiment, which differs from that described above with reference to Figures 3 to 9 in that the tabs 35 have been replaced by tabs 38 extend axially towards the lid . The tabs 38 are at least three in number, are elastically deformable and the free ends of said tabs 38 are provided with snap hooks 39.

Said tabs 38 are snapped onto the radially inner periphery 4 of the cover 2, so as to form a subassembly pre-assembled, the assistance washer 30 then being held between the intermediate washer 33 and the lid 2.

As before, the assistance washer 30 bears on the diaphragm 10 via the intermediate washer 33, in particular via the annular portion 34 of the intermediate washer 33.

In the disengaged position, the assistance washer 30 is held in axial position by means of the snap hooks 39 of the intermediate washer 33. This limits the wear on the supports of the assistance washer 30.

Figures 12 and 13 illustrate an assembly according to a third embodiment, which differs from that described above with reference to Figures 3 to 9 in that the tabs 35 have been replaced by tabs 40 extend axially towards the cover. The tabs 40 are at least three in number, are elastically deformable and the free ends of said tabs are provided with snap hooks 41.

Said tabs 40 are engaged on the radially inner periphery of the support washer 30, in particular on the face 42 of the annular portion 31 turned towards the cover 2, so as to form a pre-assembled subassembly.

FIGS. 14 and 15 illustrate an assembly according to a fourth embodiment, which differs from that described above with reference to FIGS. 3 to 9 in that the intermediate washer 33 is devoid of tabs, the intermediate washer 33 being overmolded on the periphery radially. internal of the annular portion 31 of the support ring 30, so as to be integral and form a subset. More particularly, the intermediate washer 33 has a radial portion 34 resting on the face of the assistance washer 30 facing the diaphragm 10, and a cylindrical rim 43 radially internal extending inside the radially inner periphery of the assistance washer 30.

As previously, the assistance washer 30 bears on the diaphragm 10 via the intermediate washer 33, in particular via the radial annular portion 34 of the intermediate washer 33.

The modes described in FIGS. 7 and 8 and FIGS. 12 and 13 may be combined so that the assistance washer 30 can be secured in axial displacement with the diaphragm 10.

Claims

1. Assembly (1) for a clutch device, particularly for a motor vehicle, comprising a cover (2) having an axis (X), a pressure plate (9) movable relative to the cover (2) along said axis (X) and actuated by a diaphragm (10) interposed axially between the cover (2) and the pressure plate (9), the diaphragm (10) being movable between the engaged position and a disengaged position, an elastically deformable support washer (30) , interposed axially between the cover (2) and the diaphragm (10) and capable of exerting a variable axial force as a function of the position of the diaphragm (10), characterized in that the assistant washer (30) is supported on the diaphragm (10) via an intermediate member (33) of synthetic material.

2. Assembly (1) according to claim 1, characterized in that the intermediate member is a washer (33) of annular shape.

3. Assembly (1) according to claim 1 or 2, characterized in that the intermediate member (33) comprises latching means (35) adapted to snap onto the diaphragm (10).

4. Assembly (1) according to claim 3, characterized in that the diaphragm (10) has an annular portion (12) and fingers (13) extending radially inwardly from the annular portion (12), the latching means comprising tabs (35) snapping between the fingers (13) of the diaphragm (10).

5. The assembly (1) according to claim 1 or 2, characterized in that the intermediate member (10) comprises latching means (38) adapted to snap onto the cover (2).

6. Assembly (1) according to claim 5, characterized in that the cover (2) comprises an annular radial portion (3), the latching means having tabs (38) snapping on the radially inner periphery (4) of the annular radial portion (3) of the lid (2).

7. Assembly (1) according to claim 1 or 2, characterized in that the intermediate member (33) comprises latching means (40) adapted to snap onto the assistance washer.

8. Assembly (1) according to claim 7, characterized in that the latching means comprises tabs (40) snapping on the radially inner or outer periphery of the support washer (30).

9. Assembly (1) according to claim 1 or 2, characterized in that the intermediate member (33) is overmoulded on said support washer (30).

10. Assembly (1) according to one of claims 1 to 9, characterized in that the radially inner periphery of the support washer (30) bears on the intermediate member (33), the radially outer periphery of the assistance washer (30) being supported on the cover (2).

1 1. Assembly (1) according to claim 10, characterized in that the radially outer periphery of the support washer (30) comprises tabs (32) extending radially outwards, said tabs (32) being supported on the lid (2).

12. Assembly (1) according to one of claims 1 to 1 1, characterized in that the intermediate member (33) is produced by injection molding of polymer-type material or by an additive manufacturing method such as the three-dimensional printing.