CN110382906B

CN110382906B - Clutch disc with friction washer

Info

Publication number: CN110382906B
Application number: CN201880016798.5A
Authority: CN
Inventors: L.安德雷德; M.阿尔梅达
Original assignee: Valeo Embrayages SAS
Current assignee: Valeo Embrayages SAS
Priority date: 2017-03-17
Filing date: 2018-03-16
Publication date: 2021-12-28
Anticipated expiration: 2038-03-16
Also published as: BR112019018147B1; BR112019018147A2; RU2019132705A; RU2019132705A3; FR3064036A1; CN110382906A; WO2018167440A1; FR3064036B1

Abstract

A clutch disc (1) comprising a peripheral torque transmitting member (2), a central torque transmitting member (3) and at least one torsional damping device comprising at least a load spring washer (27) and a friction washer (28). The central torque transmitting member (3) comprises a rotational drive element (40) for simultaneously rotating the load spring washer (27) and the friction washer (28). The load spring washer (27) and the friction washer (28) each comprise on their inner contour a receiving element (31, 33), the receiving elements (31, 33) being angularly arranged so as to cooperate simultaneously with the rotary drive element (40).

Description

Clutch disc with friction washer

Technical Field

The present invention relates to the field of power transmission in motorized devices and to clutches. More particularly, it relates to a clutch disc.

Background

For example, a motor vehicle may be provided with a clutch interposed between the engine and the transmission. The clutch generally includes a clutch mechanism and a clutch plate including a peripheral torque transmitting member and a central torque transmitting member. When the clutch is engaged, the engine is coupled to the transmission through the clutch disc. The peripheral torque transmitting members are then typically clamped by the clutch mechanism so as to be constrained to rotate with the engine, and the central torque transmitting member is constrained to rotate with an element of a transmission (such as a transmission of a vehicle). When the clutch is disengaged, the clutch mechanism releases the clutch plate and the engine is disengaged from the transmission.

In addition to its function of coupling the engine and transmission, the clutch disc typically has ancillary functions related to filtering non-cyclical engine behavior and other torsional oscillations. Such filtering is typically applied by one or more torsional dampers, which are combined spring-dampers that operate torsionally and enable relative rotational movement of the peripheral torque transmitting members with respect to the central torque transmitting member and dampen such relative rotation during torque transmission. The relative rotation can be achieved by a spring and the damping can be generated by a friction washer axially loaded by the spring washer in order to dissipate the energy accumulated in the spring by friction.

In designing the clutch disc, particular attention is paid to the selection of the materials constituting the torsional damper, the load to be applied to the friction washers, and the means of driving the various elements causing the dissipation of energy by friction.

Document FR2801081 describes a clutch disc comprising spring washers and friction washers, some of which are constrained to rotate with the other washer, by one washer bearing against a radially internal annular edge of the other washer or by a radial lug on the outer periphery of one washer engaging a notch on the inner periphery of the other washer.

As such, document FR2890141 describes a clutch disc in which a metal washer receives on one of its faces a plastic washer which is constrained to rotate with it due to axial projections and recesses to prevent metal-to-metal contact.

The prior art solutions are able to place the friction area in place and prevent undesired friction patterns, such as metal-to-metal friction. However, these solutions are obtained after increasing the number of nesting or other lugs or increasing the number of parts (such as staggered plastic washers) at the expense of increasing the complexity of the washers and their installation.

Disclosure of Invention

The object of the present invention is to improve the clutch disc of the prior art.

To this end, the invention relates to a clutch disc for coupling an engine and a transmission, comprising a peripheral torque transmitting member and a central torque transmitting member mounted for rotational movement relative to each other about an axis, and at least one torsional damping device disposed between the peripheral torque transmitting member and the central torque transmitting member, the torsional damping device comprising at least one spring adapted to deform upon rotation of the peripheral torque transmitting member and the central torque transmitting member relative to each other, a load spring washer and a friction washer coaxial with the central torque transmitting member, the load spring washer applying an axial load to the friction washer. The central torque transmitting member comprises a rotational drive element for simultaneously rotationally driving the load spring washer and the friction washer, and the load spring washer and the friction washer each comprise a receiving element on their radially inner profile, the receiving elements being angularly arranged such that the load spring washer and the friction washer are simultaneously driven by the rotational drive element.

Simultaneous rotational drive load spring washers and friction washers involve joint movement of the two washers without relative rotation with respect to each other. This relative rotation of one washer on the other will result in rapid and uncontrollable wear, especially if the two washers are made of metal. The wear of one washer on the other particularly results in a change in the load exerted by the loaded spring washer and therefore in a general interruption of the torsional damping function.

Friction between the two washers is prevented without having to resort to a system for mechanically fixing one washer relative to the other washer or one washer relative to another component of the clutch disc. The receiving element can be simply integrated into the geometry of the washer without additional costs and without increasing the overall dimensions in the radial direction of the simple planar washer. Due to the arrangement of the rotary drive element of the central torque transmitting member and the receiving element of the washer, it is dynamically achieved that one washer is constrained to rotate together with the other washer.

In the field of clutch discs, it is crucial to reduce the overall size in the radial direction and to simplify it by reducing the number of components or their complexity. The clutch disc according to the invention achieves advantages in terms of compactness, simplicity and production costs.

The clutch disc may also have the following additional features, either alone or in combination:

the rotary drive element comprises at least one outer tooth extending radially from the central torque transfer member in the direction of the peripheral torque transfer member;

the receiving element of each washer comprises at least one internal tooth which extends radially from the inner diameter of the washer in the direction of the axis of rotation;

the central torque transfer member is a hub adapted to cooperate with the gearbox input shaft;

the rotary drive element comprises a first surface for simultaneously rotating the drive washers in a relative rotational direction of the central member with respect to the peripheral torque transfer members, and a second surface for simultaneously rotating the drive washers in another relative rotational direction;

the central torque-transmitting member has a possible angular movement between a position in which the first surface simultaneously rotationally drives the washers in one relative rotational direction and a position in which the second surface simultaneously rotationally drives the washers in the other relative rotational direction, the washers therefore being rotationally driven only over a portion of the angular travel of the central torque-transmitting member for so-called "slipping" actuation of the friction washers;

the damping device comprises an anti-error yoke device which obtains a predetermined relative angular position between a friction washer and a load spring washer in the damping device;

the spring is adapted to deform between the central torque transmitting member and a rotary member driven by the peripheral torque transmitting member, the rotary member having a complementary friction surface, the friction washer being arranged to rub against the complementary friction surface of the rotary member;

the rotary members are further adapted to be rotationally driven together with the central torque transmitting member beyond a predetermined angular relative movement between the rotary members and the central torque transmitting member;

the rotary member has a driving inner profile adapted to cooperate with the rotary driving element beyond a predetermined angular relative movement between the rotary member and the central torque-transmitting member;

-a load spring washer and a friction washer are provided in a cartridge, the cartridge being constrained to rotate with the rotary member, the rotary member being further adapted to be rotationally driven with the central torque transmitting member beyond a predetermined angular relative movement between the rotary member and the central torque transmitting member, the friction washer being provided to rub against the rotary member;

the load spring washer is arranged against the cassette in a contact zone, which may be located at the periphery of the load spring washer;

the load spring washers comprise anti-mistake yoke lugs adapted to cooperate with the first anti-mistake yoke housings of the cassettes, these first anti-mistake yoke housings having a width greater than the width of said anti-mistake yoke lugs, so as to allow a relative angular travel between the load spring washers and the cassettes;

-the anti-mistake yoke lug is bent in the direction of the cassette;

the friction washers comprise anti-mistake yoke lugs adapted to cooperate with the second anti-mistake yoke housings of the cartridge, these second anti-mistake yoke housings having a width greater than the width of said anti-mistake yoke lugs, so as to allow a relative angular travel between the friction washers and the cartridge;

the cartridge comprises a mounting angle error-proofing yoke member;

the receiving elements of the friction washers and of the load spring washers each comprise at least one complementary first driving surface and at least one second complementary driving surface, the external toothing of the central torque-transmitting member being angularly arranged between the first and second complementary driving surfaces so as to be in contact with the first complementary driving surface in one relative rotational direction and with the second complementary driving surface in the other relative rotational direction, respectively, the angular spacing between the first and second complementary driving surfaces of the friction washers being similar to the angular spacing between the first and second complementary driving surfaces of the load spring washers so as to obtain simultaneous driving without relative rotation of the load spring washers and the friction washers by the external toothing;

the load spring washer and the friction washer have the same internal profile;

the clutch disc comprises two damper stages, namely a main damper stage between the peripheral torque transmitting member and the rotary member and a secondary damper stage between the rotary member and the central torque transmitting member, the torque damping means corresponding to the secondary damper stage, in particular to the pre-damper;

the central torque-transmitting member has a radially outer profile, the drive element forming at least a part of the radially outer profile, another part of the radially outer profile forming a housing for the spring;

the central torque transmitting member comprises a plurality of drive elements and a plurality of housings for springs, the housings for springs being arranged circumferentially between the drive elements;

the housing for the spring and the drive element are arranged axially such that there is a plane perpendicular to the axis of rotation, which plane passes through both the housing for the spring and the drive element of the central transmission member.

Drawings

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

figure 1 is an exploded view of a clutch disc according to the invention;

figure 2 is a cross-sectional perspective view of the clutch disc of figure 1;

figure 3 is a detailed view of figure 2;

FIG. 4 is an exploded partial view of the clutch of FIG. 1;

figure 5 is a perspective view of a load spring washer of the clutch disc of figure 1;

figure 6 is a perspective view of the friction washer of the clutch disc of figure 1;

figure 7 is a perspective view of the gasket of figure 5 shown in a box;

figures 8 and 9 are partial cross-sectional views of figure 7;

figure 10 is similar to figure 7, also showing the friction washer of figure 6 mounted in the box;

figures 11 and 12 are partial cross-sectional views of the assembly of figure 10;

FIG. 13 is a view from above of the elements and central torque transmitting member shown in FIG. 4;

figures 14 to 17 show the elements of figure 13 in different angular positions;

figures 18 and 19 are cross-sectional views of the cartridge of figures 7 and 10.

Detailed Description

In the description and claims, the terms "outer" and "inner" and "axial" and "radial" orientations will be used in accordance with the definitions given in the description of the components of the torsional damper. The axis of rotation (X) (as shown in fig. 2) defines an "axial" orientation. The "radial" orientation is perpendicular to the axis (X). The "circumferential" orientation is perpendicular to the rotation axis (X) and perpendicular to the radial direction. The terms "outer" and "inner" are used to define the relative position of one component with respect to the other with reference to the axis of rotation (X), so that the component close to said axis is described as inner, as opposed to the outer component, which is located radially outside. Moreover, the angles and angular sectors are defined with reference to the rotation axis X.

Fig. 1 is an exploded perspective view showing components constituting a clutch disc 1 for a motor vehicle in this example. This same clutch disc is shown in assembled and cross-sectional view in figure 2.

The clutch disc 1 is designed to couple an engine and a transmission of a motor vehicle. It comprises peripheral torque transmitting members, here comprising friction discs 2, and central torque transmitting members, here comprising a hub 3. The clutch disc is typically assembled such that the friction disc 2 can be clamped by a clutch mechanism connected to the engine flywheel, and the hub 3 is constrained to rotate with the input shaft of the vehicle's gearbox by internal teeth 23 on the hub 3.

The friction disc 2 comprises a support disc 4, on both sides of which two friction panels 5 are mounted 4. Two flanges, referred to as "first guide washer" 6 and "second guide washer 7", are fixed to respective opposite sides of the friction disc 2. Rivet 8 fastens support disc 4 and guide washers 6, 7 together. A rotating element, here a disc called "web" 9, is also mounted between the two guide washers 6, 7.

The clutch disc 1 for transmitting torque between an engine and a transmission is capable of transmitting torque from the friction panel 5 to the hub 3 (engine driving the transmission) or from the hub 3 to the friction panel 5 (transmission driving the engine in the case of engine braking a vehicle, for example).

The clutch disc further comprises a primary torsional damper disposed between the web 9 and the guide washers 6, 7 and a secondary torsional damper (also referred to as a "pre-damper") disposed between the hub 3 and the web 9. The primary damper is used to filter rotational oscillations at high loads, such as those that occur when the vehicle is moving, while the secondary damper filters rotational oscillations at low loads, such as those associated with engine idle speed.

In order to provide the function of a main damper, the web 9 comprises first windows 10 and the two guide washers 6, 7 comprise second windows 11 arranged with respect to the first windows 10 of the web 9, so that a spring 12 can be arranged between each first window 10 of the web 9 and a corresponding pair of the second windows 11 in the guide washers 6, 7 (see fig. 2). The web 9 can rotationally drive the guide washers 6, 7 (or vice versa) by means of a compression spring 12.

The main damper further includes one or more sets of washers, each set including a load spring washer and a friction washer. The sets of washers supplement the action of the springs 12 by dissipating the energy accumulated by the springs 12 through friction. Here, the main damper comprises a first set of washers including a first friction washer 13 and a first spring washer 14 applying an axial load thereto. The first friction washer 13 and the first spring washer 14 are constrained to rotate with the first guide washer 6 by means of tabs 15 engaged in lugs 16 and fixed in holes 17 in the first guide washer 6. Thus, the first friction washer 13 rubs on the web 9 during the relative rotation between the web 9 and the first guide washer 6.

The second set of washers of the main damper comprises a second spring washer 18 which applies an axial load to a second friction washer 19, the second friction washer 19 rubbing on the hub 3 during relative rotation of the hub 3 and the first guide washer 6. The second spring washer 18 and the second friction washer 19 are constrained to rotate with the first guide washer 6 by means of tabs 20 engaged in lugs 21 and fixed in holes 22 in the first guide washer 6.

The two sets of washers connected to the main damper are of conventional construction and require

tabs

15, 20, lugs 16, 21 and apertures 17, 22 for rotationally fixing the

washers

15, 16, 18, 19 relative to one another.

In the case of secondary dampers, the hub 3 comprises on its outer contour the shell 24 and the web 9 comprises on its inner contour the panel complementary shell 25, so that the spring 41 can be inserted between the web 9 and the hub 3 at the level of each pair of

shells

24, 25. The box 26 is fixed to the web 9 and contains a set of washers, here comprising a load spring washer 27 and a friction washer 28, the load spring washer 27 exerting an axial load between the box 26 and the friction washer 28 and thus pressing the latter against the web 9.

Fig. 3 is a larger-scale view of the dotted rectangle in fig. 2. It shows the relative positions of the cassette 26, the

gaskets

27, 28 and the web 9. When relative rotation occurs between the web 9 and the hub 3, friction of the friction washer 28 on the web 3 may be activated to dissipate energy and dampen rotation in the manner shown below.

Fig. 4 shows the cassette 26, the spring washer 27, the friction washer 28 and the web 9, respectively, in an exploded view. In the present example, the cartridge 26 is made of a plastic material and is fixed against the web 9. On its periphery, there are fixing pins 29 which are fixed in the mounting holes 42 of the web 9. This fixation and the geometry of the box 26 determine the axial spacing available to accommodate the

washers

27, 28, so that the spring washer 27 is compressed and exerts a predetermined axial load on the friction washer 28.

Fig. 5 is a perspective view of the spring washer 27, the spring washer 27 here being made of steel chosen for its elasticity. It has a circular overall shape and comprises on its outer contour two anti-mistake yoke lugs 30 of non-aligned diameter. The spring washer 27 comprises on its inner contour a series of receiving elements, which are here formed by internal teeth 31. These receiving elements are designed to be driven in rotation simultaneously with the friction washers 28.

The friction washer 28 is shown in perspective in fig. 6 and is here made of steel chosen for its wear resistance. It also has a circular general shape and includes two non-aligned diameter anti-mistake yoke lugs 32 on its outer profile. The friction washer 28 comprises on its inner contour a series of receiving elements, here formed by internal teeth 33. These receiving elements are designed to be driven in rotation simultaneously with the spring washer 27.

The spring washer 27 and the friction washer 28 may be stacked such that the set of internal teeth 31 of the spring washer 27 corresponds exactly to the set of internal teeth 33 of the friction washer 28. In other words, the inner profile of the spring washer 27 is the same as the inner profile of the friction washer 28. The

internal teeth

31, 33 of the

washers

27, 28 have the same shape and are arranged according to the same angular arrangement.

Fig. 7 shows the spring washer 27 mounted in the cassette 26. The cassette 26 includes a circular housing 35 for receiving the washer 27 and a fail-safe yoke housing 34 that is angularly offset relative to a diameter that mates with the fail-safe yoke lug 30 of the spring washer 27 to allow only one orientation for mounting the spring washer 27 in the cassette 26.

Fig. 8 shows the only possible mounting direction in a sectional view, in which the correct face of the spring washer 27 is positioned against the cartridge 26. In this example, the spring washer 27 bears by its outer portion on the box 26 and exerts an upward force by its inner portion (in the orientation of fig. 8), so that the spring washer 27 has a frustoconical shape. The contact between the spring washer 27 and the cartridge 26 takes place in a contact area 36, which contact area 36 is partly shown as seen from below in fig. 9. In the event of relative rotation of the spring washer 27 and the cartridge 26, the friction will be metal-to-plastic in this contact area 36.

Fig. 10 shows the assembly of fig. 7 with the addition of a friction washer 28. The friction washer 28 is mounted in a circular housing 35 of the cassette 26 from above the spring washer 27 so that its anti-mistake yoke lug 32 is placed in a suitable anti-mistake yoke housing 37 of the cassette 27.

Fig. 11 is a partial cross-sectional view of the assembly of fig. 10. Before the cartridge 26 is mounted on the web 9, the friction washer 28 rests on the spring washer 27, which is not yet compressed, as shown in fig. 11. The anti-mistake yoke lug 32 of the friction washer 28 is curved, i.e. forms an angle with the plane in which the washer 28 lies (dash-dot line in fig. 11). This property of the anti-misinterpretation yoke lug 32 makes it possible to obtain an anti-misinterpretation yoke function while the friction washer 28 is held above the edge of the box 26 by the uncompressed spring washer 27.

The cooperation between the error-

proof yoke housings

34, 37 of the cassette 26 and the

lugs

30, 32 of the

washers

27, 28 ensures that the two

washers

27, 28 are correctly mounted on a circle. Since each

anti-mistake yoke housing

34, 37 is wider than the corresponding

lug

30, 32, angular travel of the two

washers

27, 28 is allowed. Within this allowed angular travel of each

washer

27, 28 there is a relative position of the stack of the two

washers

27, 28 such that their internal profiles correspond exactly, as shown in fig. 10.

Fig. 12 is a detail view of the two

gaskets

27, 28 in this stacked position. From this perspective below, one of the spring washers 27 and its inner teeth 31 is shown, above which is one of the friction washers 28 and its inner teeth 33, said

inner teeth

31, 33 being stacked. The visible edge surfaces 38, 39 of the two

internal teeth

31, 33 lie in the same transverse plane and form complementary driving surfaces intended to cooperate with the hub 3.

Fig. 13 shows the mating with the hub 3 from above the stack in fig. 4. For ease of reading the figure, the profile of the web 9 is indicated by a dash-dot line, the profile of the box 26 (behind the web 9) by a dash-dot line, the profiles of the two

washers

27, 28 when behind the web 9 by a dash-dot line and when they are not covered by the web 9 by a solid line.

Fig. 13 shows the profile of the hub 3 and its possible interaction with the other elements drawn. The housing 24 of the hub 3 and the complementary housing 25 of the web 9 can be seen, but for the sake of simplicity the respective springs are not shown. The hub 3 also comprises, on its outer contour, elements between the housings 24 for simultaneously rotating the

drive washers

27, 28. These simultaneous rotary drive elements comprise in the present example an external toothing 40, the profile of which is complementary to the profile of the

internal toothings

31, 33 of the

washers

27, 28, so that the external toothing 40 can abut against the complementary drive surfaces described above with reference to fig. 12, according to a plane-to-plane contact, so that the edge surface of one external toothing 40 can simultaneously drive both

internal toothings

31, 33, due to their respective complementary drive surfaces, and thus can simultaneously drive the two

washers

27, 28 in rotation.

The central torque transmitting member comprises a plurality of driving elements and a plurality of housings 24 for springs 41, the housings 24 for springs 41 being arranged circumferentially between the driving elements. The housing 24 for the spring 41 and the drive element are arranged axially such that there is a plane perpendicular to the axis of rotation, which plane passes through the housing 24 for the spring 41 and through the drive element of the central transmission member 3.

Furthermore, the inner contour of the web 9 comprises a receiving element, which is constituted here by an angularly arranged tooth 48, in order to be able to be driven in rotation also by the hub 3.

Fig. 14 to 17 are views on a larger scale of fig. 13 for different angular positions of the hub 3 and illustrate the possibility of dynamic interaction between the latter and the other components of the assembly.

Fig. 14 shows a position in which, starting from the position of fig. 13, the hub 3 is rotated clockwise relative to the web 9 until each outer tooth 40 is in contact with the

washers

27, 28, more precisely until the first surface 46 of each outer tooth 40 is in contact with a pair of stacked

inner teeth

31, 33. The internal teeth 31 of the spring washer 27 and the internal teeth 33 of the friction washer 28 are stacked, and the same dotted and dashed lines in fig. 14 indicate the internal profile of the spring washer 27 and the internal profile of the friction washer 28.

In the position of fig. 14, the first surface 46 of each outer tooth 40 is in contact with the first complementary drive surfaces 38, 39 of the

inner teeth

31, 33 of the

washers

27, 28, as shown in fig. 12.

During rotation from fig. 13 to 14, the spring 41 (not shown) is compressed, while the

washers

27, 28 remain fixed relative to the web 9. Thus, the friction washer 28 does not operate to dissipate energy by friction, and the hub 3 rotationally drives the web 9 by compressing the spring 41.

Starting from fig. 14, if the relative rotation of the hub 3 in the clockwise direction continues, the internal teeth 40 simultaneously rotate the drive spring washer 27 and the friction washer 28. This simultaneous rotation changes the angular position of the two

washers

27, 28 without relative movement between them. During the simultaneous rotation, the friction washer 28 exerts its energy dissipation function by rubbing the web 9, the web 9 being axially loaded by the spring washer 27, the spring washer 27 being driven in the same rotation, rubbing on the cartridge 26 as it were.

Simultaneous rotation of the

washers

27, 28 continues to the position of fig. 15, where each outer tooth 40 of the hub 3 meets the inner profile of the web 9. In this position, each first surface 46 of the external teeth 40 abuts on a first complementary drive surface of the stack of

internal teeth

31, 33 of the two

washers

27, 28 and also on a tooth 48 of the web 9.

From this fig. 15 position, if the clockwise relative rotation of hub 3 continues, hub 3 no longer drives web 9 by compression of spring 41, but it is driven directly by mechanical contact of first surface 46 of external teeth 48 with the teeth of web 9. The secondary damper then no longer serves and damping of torsional oscillations is provided only by the primary damper provided between the web 9 and the guide washers 6, 7.

Thereafter, when the secondary damper is returned to service, more specifically when the hub 3 rotates in the anticlockwise direction with respect to the web 9, the hub 3 therefore reaches the position of figure 16 without any relative rotation of the

washers

27, 28 with respect to the web 9 and the box 26. The web 9 then drives the hub 3 in rotation by the compression spring 41 without the action of the friction washer 28.

In fig. 16, each external tooth 40 of the hub 3 is in contact with a

washer

27, 28, more precisely the second surface 47 of each external tooth 40 is in contact with a pair of second complementary driving surfaces, each carried by one of the stacked

internal teeth

31, 33.

Starting from fig. 16, if the relative rotation of the hub 3 in the counterclockwise direction continues, the internal teeth 40 simultaneously rotate the drive spring washer 27 and the friction washer 28. As previously described, simultaneous rotation changes the angular position of the two

washers

27, 28 without relative movement therebetween. During the simultaneous rotation, the friction washer 28 exerts its energy dissipation function by rubbing the web 9, the web 9 being axially loaded by the spring washer 27, the spring washer 27 being driven in the same rotation, rubbing on the cartridge 26 as such.

Simultaneous rotation of the

washers

27, 28 continues to the position of fig. 17, where each outer tooth 40 of the hub 3 meets the inner profile of the web 9. In this position, the second surface 47 of each external tooth 40 bears against the second complementary driving surface of the stack of

internal teeth

31, 33 of the two

washers

27, 28 and also against the tooth 48 of the internal profile of the web 9.

From this fig. 17 position, if the relative rotation of the hub 3 in the anticlockwise direction continues, the web 9 directly drives the hub 3 through mechanical contact, the secondary damper is no longer in service and only the primary damper is active.

Thus, the function of the friction washer 28 of the secondary damper is obtained at the appropriate time, i.e. in the present example, according to the predetermined angular stroke before deactivation of the secondary damper. This angular travel is performed without relative friction between the friction washer 28 and the spring washer 27, but the friction washer 28 rubs on the web 9 and the spring washer 27 rubs on the box 26. Thus, the

washers

27, 28 are driven in rotation only over a portion of the angular travel of the hub, for the so-called "slipper" actuation energy dissipation of the friction function exerted by the friction washer 28.

In exceptional cases where the two

washers

27, 28 are angularly decelerated, for example due to shocks or vibrations, they will be rapidly returned to their stacked position by the external toothing 40 of the hub 3 during the relative rotation of the hub 3 with respect to the web 9 to be followed. The relative rotation of the

washers

27, 28 to enable them to return to their stacked position will keep exceptions and will not cause significant wear of these

washers

27, 28.

Since the system involves rotating the drive element according to its relative angular position, the cartridge 26, the two

washers

27, 28, the web 9 and the hub 3 must be mounted in their correct relative angular positions. Thus, as previously mentioned, the spring washer 27 and the friction washer 28 must each be mounted in the box 26 from the right side in order to be able to stack the internal profiles, which is ensured by the anti-mistake yoke lugs 30, 32 and the

anti-mistake yoke housings

34, 37.

Figures 18 and 19 show a further feature which ensures correct mutual angular positioning of the cassette 26 and the web 9. The box 26 comprises a mounting angle anti-mistake yoke member 43 in the form of a hole leading to only one of the mounting pins 29 (see fig. 18 cross-section) so that any tool 44 used during manufacturing of the clutch disc 1 for handling and mounting the box 26 can be provided with an anti-mistake yoke joint 45 ensuring correct angular positioning of the box 26, as shown in fig. 19. This correct angular position is complementary to the correct angular position of the web 9, since the error-proof yoke recess 49 (see fig. 13) is also designed for correct angular positioning of the web 9 in the handling and installation tool.

As such, the hub 3 has an axially rotating asymmetric geometry (see fig. 13). In the present example, the hub 3 has two external teeth, diametrically opposite (substantially vertical in fig. 13), and on a vertical diameter (substantially horizontal in fig. 13), it comprises four teeth, two opposite but angularly offset. Thus, there is only one way to mount the hub 3 in the assembly of the web 9 and the cassette 26.

The assembly consisting of the web 9, the box 26, the load spring washer 27, the friction washer 28 and the hub 3 therefore has the advantage of ensuring a relative angular positioning which enables said interaction between the external teeth 40 of the hub 3 and the internal profiles of the

washers

27, 28 and the web 9.

Other variant embodiments may be produced without departing from the scope of the invention. For example, the examples described herein relate to a pair of

washers

27, 28 forming part of a secondary damper, it being understood that the invention includes any number of washers which may be positioned elsewhere on the clutch disc 1, in particular another torsional damper, such as a primary damper, as long as at least one load spring washer and one friction washer each include a receiving element such that they can be simultaneously rotationally driven by the drive element of the central torque transmitting member. Similarly, with respect to clutch discs comprising multiple webs, the invention is equally applicable to clutch discs comprising only one web common to the various torsional dampers (such as those of the illustrated examples), and in particular one web for each torsional damper.

The hub may also comprise, as a simultaneous rotary drive element, a different or alternative number of external teeth 40 to the ones described in the examples.

The inner profiles of the spring washer 27 and the friction washer 28 do not need to be integrally stacked. A single receiver is sufficient for each washer and it is sufficient for these receivers to be able to simultaneously rotationally drive the washers via the rotary drive element of the central torque transfer member.

The spring washers 27 and friction washers 28 may form part of a more complex stack of washers, including multiple spring washers and multiple friction washers, where more than two washers will be simultaneously rotationally driven by the central torque transmitting member.

Claims

1. A clutch disc (1) for coupling an engine and a transmission, comprising a peripheral torque transmitting member (2) and a central torque transmitting member, which are mounted for rotational movement relative to each other about an axis X, and at least one torsional damping device arranged between the peripheral torque transmitting member (2) and the central torque transmitting member, said torsional damping device comprising at least one spring (41) adapted to deform when the peripheral torque transmitting member (2) and the central torque transmitting member rotate relative to each other, a load spring washer (27) and a friction washer (28) coaxial with the central torque transmitting member, the load spring washer (27) applying an axial load to the friction washer (28), characterized in that,

said central torque transmitting member comprising a rotational drive element for simultaneously rotationally driving the load spring washer (27) and the friction washer (28), and said load spring washer (27) and the friction washer (28) each comprising on their radially inner profile a receiving element arranged at an angle such that the load spring washer and the friction washer are simultaneously driven by the rotational drive element,

said spring being adapted to deform between said central torque transmitting member and a rotating member (9) driven by said peripheral torque transmitting member (2), which rotating member (9) has a complementary friction surface, said friction washer (28) being arranged to rub against the complementary friction surface of the rotating member (9), and

the load spring washer (27) and the friction washer (28) are arranged in a box (26), the box (26) being constrained to rotate with the rotary member (9), the rotary member (9) being further adapted to be rotationally driven with the central torque transmitting member beyond a predetermined angular relative movement between the rotary member (9) and the central torque transmitting member, the friction washer (28) being arranged to rub against the rotary member (9).

2. A clutch disc according to claim 1, characterized in that the rotary drive element comprises at least one external toothing (40) extending radially from the central torque transfer member in the direction of the peripheral torque transfer member (2).

3. A clutch disc according to any one of claims 1 and 2, characterized in that the receiving element of each washer (27, 28) comprises at least one internal tooth (31, 33) extending radially from the inner diameter of the washer (27, 28) in the direction of the axis of rotation X.

4. A clutch disc according to any one of claims 1 and 2, characterized in that the central torque transferring member is a hub (3) adapted to cooperate with the input shaft of the gearbox.

5. A clutch disc according to any one of claims 1 and 2, characterised in that the rotary drive element comprises a first surface (46) for simultaneously rotating the drive washers (27, 28) in the relative rotational direction of the central torque transmitting member with respect to the peripheral torque transmitting member (2), and a second surface (47) for simultaneously rotating the drive washers (27, 28) in the other relative rotational direction.

6. A clutch disc according to claim 5, characterised in that the central torque transmitting member has angular movement between a position in which the first surface (46) simultaneously rotates the drive washers (27, 28) in one relative rotational direction and a position in which the second surface (47) simultaneously rotates the drive washers (27, 28) in the other relative rotational direction.

7. A clutch disc according to any one of claims 1 and 2, characterized in that the damping means comprise anti-error yoke means (30, 32, 34, 37) which obtain a predetermined relative angular position between a friction washer (28) and a load spring washer (27) in the damping means.

8. A clutch disc according to claim 1, characterized in that the rotary member (9) has a driving inner profile adapted to cooperate with the rotary driving element over a predetermined angular relative movement between the rotary member (9) and the central torque transmitting member.

9. A clutch disc according to claim 1, characterized in that the load spring washer (27) is arranged against the box (26) in a contact area (36).

10. A clutch disc according to claim 9, characterized in that the contact zone (36) is located at the periphery of the load spring washer (27).

11. A clutch disc according to any one of claims 1, 9 and 10, characterized in that the load spring washer (27) comprises error-proof yoke lugs (30) adapted to cooperate with first error-proof yoke housings (34) of the cassette (26), the width of these first error-proof yoke housings (34) being greater than the width of the error-proof yoke lugs (30) so as to allow relative angular travel between the load spring washer (27) and the cassette (26).

12. A clutch disc according to claim 11, characterized in that the anti-mistake yoke lug (30) is bent in the direction of the cassette (26).

13. A clutch disc according to any one of claims 1, 9 and 10, characterized in that the friction washer (28) comprises anti-mistake yoke lugs (32) adapted to cooperate with second anti-mistake yoke housings (37) of the cassette (26), the width of these second anti-mistake yoke housings (37) being greater than the width of the anti-mistake yoke lugs (32) in order to allow relative angular travel between the friction washer (28) and the cassette (26).

14. A clutch disc according to any one of claims 1, 9 and 10, characterized in that the cassette (26) includes a mounting angle error proofing yoke member (43).

15. A clutch disc according to claim 5, characterized in that the rotary drive element comprises at least one external toothing (40) extending radially from the central torque transfer member (2) in the direction of the peripheral torque transfer member, and the receiving element of the friction washer and the receiving element of the load spring washer each comprise at least one first and one second complementary drive surfaces, the external toothing of the central torque transfer member being angularly arranged between the first and second complementary drive surfaces so as to be in contact with the first and second complementary drive surfaces, respectively, in one relative rotational direction and in the other relative rotational direction, the angular separation between the first and second complementary drive surfaces of the friction washer and the angular separation between the first and second complementary drive surfaces of the load spring washer The same in order to obtain simultaneous driving without relative rotation of the load spring washer and the friction washer by said external teeth.

16. A clutch disc according to either of claims 1 and 2, characterized in that the load spring washer (27) and the friction washer (28) have the same internal profile.

17. A clutch disc according to either of claims 1 and 2, characterized in that it comprises two damper stages, a primary damper stage between the peripheral torque transmitting member (2) and the rotary member (9) and a secondary damper stage between the rotary member (9) and the central torque transmitting member, the torque damping means corresponding to the secondary damper stage.

18. A clutch disc according to any one of claims 1 and 2, characterized in that the central torque-transmitting member has a radially outer profile, the rotary drive element forming at least a part of the radially outer profile, another part of the radially outer profile forming a housing (24) for the spring (41).

19. A clutch disc as claimed in claim 17, characterised in that the torque damping means corresponds to a pre-damper.