FR3075288A1 - TRANSMISSION DEVICE WITH BALANCING MEANS - Google Patents

Abstract

 Torque transmission device (1) for a motor vehicle powertrain, comprising:  a friction element (2) movable in rotation about an axis of rotation X, the friction element comprising a friction zone (3) capable of being pinched by a torque transmission mechanism (50),  - a shock absorber (4) comprising a shock absorber input element (5), a shock absorber output element (8), at least one spring (10) being arranged between the shock absorber input element ( 5) and the shock absorber output element (8) so as to compress to filter acyclisms, and the friction element (2) being fixed to the shock absorber input element (5),  - at least one balancing means (11),

Description

TRANSMISSION DEVICE WITH BALANCING MEANS

Technical area

The invention relates to the field of torque transmission devices, in particular for motor vehicle powertrains.

The invention also relates to a transmission assembly comprising a torque transmission device and a transmission mechanism.

Technological background

Motor vehicle transmissions are generally equipped with a torsion damper to filter vibrations upstream of the gearbox so as to avoid particularly undesirable impacts, noises or noise pollution. Such damping systems equip in particular the double damping flywheels (DVA) and / or the clutch friction, in the case of a manual or robotic transmission, or the locking clutches, also called “lock-up” clutches. , fitted to the hydraulic coupling devices, in the case of an automatic transmission.

Damping systems comprise elastic damping means coupling in rotation an input element and an output element so as to allow a transmission of the torque and a damping of the rotation acyclisms.

In the prior art, it is known to reduce the unbalance phenomenon by using balancing nails which are positioned in the shock absorber at suitable locations to compensate for the unbalance phenomenon, which was observed before the installation of the balancing nail.

This type of solution is for example described in the document FR2669387. However, the positioning of the nail on the guide washers does not allow this nail to be positioned beyond a certain distance from the axis of rotation, a distance imposed by the radius of the guide washer. However, the greater the distance from the axis of rotation at which the balancing nail is installed, the more effective the balancing. Conversely, the closer the balancing nail is positioned to the center, the greater its mass must be, which does not go in the direction of lightening the torque transmission device. Furthermore, circumferentially, the nail cannot be placed where desired on the guide washers because certain zones of the guide washer are dedicated to the fixing of the friction element and it is also difficult to use the zones of the guide washer near the springs to mount a balancing means there.

Previous solutions are also known in which certain components of the transmission device have been modified to make them play, in addition to their initial function, the balancing function. This approach does not allow standardization of parts. Finally, using an existing component to make it play the balancing function does not play on the mass of the device exactly where desired. Balancing possibilities are therefore limited.

In addition, it may be useful to implement the balancing means at the end of assembly according to the intended use for the transmission device, which is not possible when the balancing function is provided by a component ensuring another function in the transmission device (stop, spacer, assembly of parts)

summary

An idea underlying the invention is to provide a torsional damper with good balancing, with standard components, and with great freedom of installation of the balancing means, circumferentially.

An idea underlying the invention is also to provide an effective balancing device which does not overly burden the transmission device.

One idea underlying the invention is to differentiate the transmission device as late as possible in the manufacturing process according to its balancing means.

For this, the invention provides, according to claim 1, a torque transmission device for a motor vehicle powertrain, comprising:

a friction element movable in rotation about an axis of rotation X, the friction element comprising a friction zone capable of being pinched by a torque transmission mechanism,

a shock absorber comprising a shock absorber input element, a shock absorber output element, at least one spring being arranged between the shock absorber input element and the shock absorber output element so as to be compress to filter acyclisms, and the friction element being fixed to the shock absorber input element,

- at least one balancing means.

In a plane comprising the axis of rotation X and passing through the balancing means, the balancing means is arranged radially between the damper input element and the friction zone.

Thus, the invention offers great freedom of balancing.

According to other advantageous embodiments, such a transmission device can have one or more of the following characteristics:

The shock absorber input element has an outer contour, and each balancing means is arranged radially outside the outer contour of the shock absorber element.

The damper has an outer contour and each balancing means is arranged radially outside the outer contour of the damper input element.

The torque transmission device comprises a plurality of balancing means and each balancing means is arranged, in a plane comprising the axis of rotation X and passing through this balancing means, radially between the input element shock absorber and friction zone.

- According to one embodiment, in the plane comprising the axis of rotation X and passing through the balancing means, the support disc is devoid of balancing means on the other side of the axis of rotation X.

The balancing means is arranged on the friction element.

The balancing means is connected only to the friction element.

The balancing means is connected only to the friction element. In other words, the balancing means is not a fixing element used to assemble two parts of the transmission device.

The balancing means is integrated into the friction element.

The balancing means is a recess in the friction element. Balancing the transmission device also makes it possible to lighten it.

The balancing means is a recessed or machined area of the friction element.

The balancing means is a hole formed in the friction element.

The balancing means is an element adding mass locally to a part of the torque transmission device, in particular a part of the friction element. This reduces the risk of embrittlement linked to the removal of material. The addition of mass makes it easier to balance the transmission device, and gives more room for maneuver for balancing.

The balancing means is a rivet.

The rivet is attached to the friction element.

The balancing means is a rivet with two heads enclosing the friction element, one of the heads being heavier than the other of the heads. In particular, the mass of one of the heads is at least twice the mass of the other of the heads. The heaviest rivet head is called a balancing head.

The balancing means is a blind rivet or a broken pin.

The balancing means is a solid rivet.

The balancing means is a member welded or clipped to the friction member.

The friction element includes an attachment portion, the attachment portion of the friction element being attached to a radially outer region of the shock absorber input element.

The fixing portion of the friction element is located on a radially inner region of the friction element.

The friction zone is located on a radially outer zone of the friction element.

The balancing means is arranged on an intermediate zone of the friction element located radially between the fixing portion and the friction zone of the friction element.

The damper input element has, in a plane perpendicular to the X axis, a wavy outline around the X axis, the wavy outline having at least two ridges arranged circumferentially on either side of a hollow, at least part of the balancing means being arranged circumferentially between two ridges of the damper input element.

The crests have an extremum defining an outer crest diameter and the balancing means can be arranged at least partially within this maximum diameter. Thus, this solution makes it possible to reduce the inertia of the damper input element while keeping the balancing means fairly far from the axis X. Such a wavy contour is for example useful when it is desired to limit the inertia of the damper input element.

The friction element has an annular shape around the X axis.

As a variant, the friction element is a pale one extending over a limited angular sector around the axis X, in particular over a sector from 10 to 45 degrees.

The friction element carries at least one lining, said at least one lining being carried by the friction zone of the friction element.

The lining has an interior contour, and each balancing means is arranged radially inside this interior contour.

The friction element has axial progressiveness. In other words, it has deformable portions capable of exerting axial elastic restoring forces opposing the pinching forces of the friction element.

The shock absorber input element has at least one guide guide washer axially retaining the spring.

The shock absorber input element has two guide washers arranged axially on either side of the springs.

The two guide washers are arranged at a fixed axial distance from each other.

The two guide washers are mounted integral in rotation.

For example, spacers fasten the two guide washers in rotation and keep them at a fixed distance from each other.

The damper outlet element is a web arranged axially between the two guide washers.

The torque transmission device comprises a driven member coupled to the shock absorber output element and capable of driving a gearbox input shaft.

The driven member is a hub comprising internal splines arranged to cooperate with external splines of a gearbox input shaft.

The hub is coupled to the damper outlet element via a gear ring on the hub.

The driven member is integral in rotation with the damper outlet element.

The spring bears on one of its ends against the two guide washers and on the other of its ends against the web.

The axial length of the balancing means is greater than the axial thickness of the web.

The damper input element has a clearance of material or notch, the balancing means occupying at least part of the space left by this clearance of material or notch. Thus, the damper input element can be lightened while maintaining the balancing means at a satisfactory distance from the axis of rotation.

The guide washers are rotatably mounted around the hub by means of bearings.

The transmission device includes a pendulum damper.

The pendulum shock absorber has a pendulum support that rotates around the axis of rotation.

The pendulum support is mounted for rotation with the damper outlet element.

The pendulum shock absorber is centered on the driven organ by means of its pendulum support.

The pendulum support can be integral in rotation with the driven member, for example by force mounting, or by means of grooves.

The pendulum support can be mounted integral in rotation with the shock absorber outlet element. The pendulum support can be mounted directly on the shock outlet element.

The mounting integral in rotation with the pendulum support relative to the shock absorber outlet element or the driven member must be interpreted as integral in rotation at least up to a certain level of torque, the presence of another limiter of torque (aimed at protecting the pendulum from overtorques) between on the one hand the damper outlet element or the driven member, and on the other hand, the pendulum support, not being excluded from this invention.

The pendulum damper comprises at least one pendulum mass, preferably a plurality of pendulum masses, able to move freely relative to the pendulum support and guided by this same pendulum support.

The pendulum mass can be mounted on the outer periphery of the pendulum support. The pendulum mass is driven by a pendulum movement in operation and may for example comprise two parts mounted axially on either side of the pendulum support and connected to one another by one or more spacers each passing through an opening of the pendulum support. A roller can cooperate with a raceway formed in each spacer and with the edge of the corresponding opening of the pendulum support.

As a variant, the roller can cooperate with two rolling tracks, each formed in an opening of part of the pendulum mass, and with a third rolling track formed by the edge of an opening of the pendulum support different from the openings of the support. pendulum dedicated to spacers.

In each of these cases, several rollers can be provided for each pendulum mass.

Preferably, the pendulum mass and the friction zone are offset axially.

- According to one embodiment, the balancing means is arranged radially beyond the internal radial edge of the pendulum masses.

Preferably, there is an axis parallel to the axis of rotation passing through both the pendulum mass and the balancing means. The balancing means and the pendulum mass can therefore be axially opposite one another.

The friction element comprises an annular disc arranged around the X axis. Alternatively, the friction element comprises a plurality of blades regularly distributed around the X axis.

The friction element comprises a plurality of implantation points, each implantation point being able to receive a balancing means.

The friction element has a plurality of balancing zones, each balancing zone having a plurality of implantation points.

The shock absorber input element has a clearance or notch in axial opposite of each balancing zone.

The implantation points are regularly distributed around the X axis.

The invention also relates to a transmission assembly comprising:

- the transmission device according to one of the preceding claims,

- A pressure mechanism arranged to permanently or temporarily pinch the friction element at the level of said at least one friction zone.

According to other advantageous embodiments, such a transmission assembly may have one or more of the following characteristics:

The pressure mechanism is a torque limiter.

The torque limiter comprises a support washer, a pressure washer, a reaction washer, the friction element being arranged axially between the pressure washer and the reaction washer, a spring arranged between the support washer and the pressure washer so as to press the pressure washer against the friction zone so that the friction zone is pinched by the pressure washer and the reaction washer;

- the torque limiter has an annular space axially separating the support washer and the reaction washer and in which the pressure washer, the spring and the friction zone of the friction element are arranged, the balancing means being also arranged at least partially in this annular space.

Thus, one can take advantage of this cavity, usually unused, to install a balancing means which is fairly effective at this location relatively distant from the axis of rotation.

The friction area of the friction element, the linings, the pressure washer, and the spring are housed in this annular space.

The mounting portions of the support washer and the reaction washer are overlapped.

At least one of the support washer and the reaction washer has an axial recess so as to create the annular space housing the friction element, the linings, the pressure washer, the spring and the means d 'balancing.

The axial recess of the support washer is oriented in a direction opposite to the axial direction of the recess of the reaction washer.

The balancing means is arranged radially inside the pressure washer. There is a radial overlap between the pressure washer and the balancing means, in particular between the balancing head of the balancing rivet (when the balancing means is a rivet) and the pressure washer,

In a plane comprising the axis of rotation X and passing through the balancing means, the balancing means is arranged radially between the web and the pressure washer.

The balancing means has an implantation axis, this implantation axis being located in the annular space of the torque limiter.

The transmission assembly may comprise a torque input member, in particular a flywheel mounted integral in rotation, by means of fixing members such as screws or rivets, the support washer and the washer. torque limiter reaction.

The support washer and the reaction washer each comprise a mounting portion, the mounting portions being assembled together and being able to be mounted together on a flywheel.

The flywheel is flexible, especially axially.

- For comparison, the axial length of the balancing means can be greater than the axial thickness of the web. The axial length of the balancing means may be greater than the axial thickness of the assembly composed of the friction element and the linings. The axial length of the balancing means can be greater than the minimum axial distance separating the guide washers. The axial length of the balancing means can be greater than the axial thickness of the pendulum in the mass area. The axial length of the balancing means can be greater than the axial thickness of the assembly composed of the friction element, the linings, and the pressure washer.

- According to another embodiment not shown, the friction mechanism is a clutch mechanism able to pinch, in a engaged mode, the friction element and able to release, in a disengaged mode, the friction element.

Brief description of the figures

The invention will be better understood, and other objects, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely by way of illustration and without limitation. , with reference to the accompanying drawings.

- Figure 1 is a front view of a transmission device according to a first embodiment of the invention.

- Figure 2 is a sectional view along AA of the torsion damper of Figure 1, the upper part corresponding to a view of the first embodiment in a plane comprising the axis of rotation X and passing through the means d 'balancing.

- Figure 3 is an enlarged sectional view of the torsional damper of Figure 1.

- Figure 4 is a perspective view showing an example of installation of balancing means.

- Figure 5 is a view of face of a rivet balancing before mounting. - Figure 6 is a view of face of a rivet balancing after mounting. - Figure 7 is a view schematic < a second mode of production. - Figure 8 is a view in perspective a third mode of

production.

- Figure 9 is a sectional view of a fourth embodiment comprising a pendulum, this sectional view corresponding to a view of the fourth embodiment in a plane comprising the axis of rotation X and passing through the means of balancing.

Detailed description of embodiments

In the description and the claims, the terms external and internal as well as the axial and radial orientations will be used to designate, according to the definitions given in the description, elements of the torsion damper.

By convention, the radial orientation is directed orthogonally to the axis X of rotation of the torsion damper determining the axial orientation and, from the inside to the outside away from said axis, the circumferential orientation is directed orthogonally to the axis of the torsion damper and orthogonally to the radial direction. The terms external and internal are used to define the relative position of an element with respect to another, with reference to the axis X of rotation of the torsion damper, an element close to the axis is thus qualified as internal as opposed to an external element located radially on the periphery.

The following description is made with reference to the figures in the context of a torque limiter for a motor vehicle, in particular for a hybrid vehicle. This description is not limiting and the invention is applicable by analogy to any other type of torque transmission device comprising a damper coupled to a friction element.

FIGS. 1 to 4 represent a torque transmission device 1 for a motor vehicle powertrain, comprising:

a friction element 2 movable in rotation about an axis of rotation X, the friction element 2 comprising a friction zone 3 capable of being pinched by a torque transmission mechanism 50,

a shock absorber 4 comprising a shock absorber input element 5, a shock absorber output element 8, springs 10 being arranged between the shock absorber input element 5 and the shock absorber output element 8 so as to compress to filter acyclisms,

The friction element 2 is fixed to the shock absorber input element 5.

To correct the imbalance phenomenon, the transmission device includes balancing means 11.

The damper input element comprises two guide washers 5 and 7 arranged axially on either side of the springs 10 and axially retaining the springs 10. The two guide washers 5 and 7 are arranged at a fixed axial distance one from the other. They are rotatably mounted by spacers 31 which, moreover, keep them at a fixed distance from one another.

The damper outlet element is a web 8 arranged axially between the two guide washers 5 and 7.

The torque transmission device 1 further comprises a hub 28 coupled to the web 8 and capable of driving a gearbox input shaft by means of internal splines 29 arranged to cooperate with external splines of the shaft.

The hub 28 is coupled to the web by means of a ring gear 32 formed in the hub which cooperates with complementary shapes formed in the internal radial contour of the web 8.

The springs 10 bear, on one of their ends, against the two guide washers 5 and 7, and on the other of their ends, against the web 8.

A friction device is interposed axially between at least one of the guide washers and the web 8 to dissipate the energy stored in the springs 0.

The guide washers 5 and 7 are rotatably mounted around the hub 28 by means of bearings 33 and 34.

Figures 1 and 2 describe the torque transmission device 1, within a transmission assembly 100 which comprises, in addition to the transmission device 1, a pressure mechanism 50.

The pressure mechanism here is a torque limiter 50 arranged to permanently pinch the friction element 3 at the level of the friction zone

3.

The torque limiter 50 includes:

- a support washer 51,

- a pressure washer 52,

a reaction washer 53, the friction element 2 of the transmission device being arranged axially between the pressure washer 52 and the reaction washer 53,

a spring 55 arranged between the support washer 51 and the pressure washer 52 so as to press the pressure washer 52 against the friction zone 3 of the friction element 2 so that the friction zone 3 is pinched by the pressure washer 52 and the reaction washer 53.

The support washer 51 of the reaction washer 53 of the torque limiter 50 can be mounted integral in rotation with a torque input member, for example a flywheel integral in rotation with the crankshaft of the vehicle. The support washer and the reaction washer each have a mounting portion 56, 57 which are superimposed on each other. Concentric orifices allow the same fixing member such as a screw to fix both the support washer 51 and the reaction washer 53 on the flywheel. If desired, the mounting portions can also be pre-assembled, for example with rivets 92, before mounting on the flywheel (Figure 2).

The pressure washer 52 is mounted integral in rotation with the support washer 51 and the reaction washer 53 by means of lugs 64 which cooperate with notches 65 made in the support washer 51.

Thus, when the torque transmitted between the crankshaft and the gearbox input shaft is less than a limit threshold S, the reaction washer 53, the friction element 2 and the pressure washer 52 rotate together.

Conversely, when the transmitted torque reaches the limit threshold S, a slip occurs at the level of the friction element 2, between the friction zone 3 of the friction element 2 and the pressure washer 52 of a part, and between the friction zone 3 of the friction element 2 and the reaction washer 53 on the other hand. Thus, the torque passing from the crankshaft to the speed shaft is limited to said limit threshold S.

In Figure 1, we see that the torque transmission device 1 comprises a plurality of balancing means 11, here three in number.

Each balancing means is arranged, in a plane comprising the axis of rotation X and passing through this balancing means, radially between the damper input element 5 and the friction zone 3 of the element of friction 2.

In this embodiment, the friction element has four balancing zones Z1, Z2, Z3 and Z4. Each balancing zone has three implantation points 88, each implantation point being capable of receiving a balancing rivet 11. Each implantation point is a hole 88 made in the friction element 2.

In each plane comprising the axis of rotation X and passing through the balancing rivet 11, the support disc is devoid of balancing rivet on the other side of the axis of rotation X.

Here, only zone Z1 is provided with balancing rivets. However, the arrangement of Figure 1 allows many combinations of rivet locations.

Here, we can see that the balancing means are only carried by the friction element 2.

The balancing rivet 11 adds mass locally to the friction element, which makes it easier to balance the transmission device.

As best seen in Figure 3, which is an enlargement of Figure 2, each balancing means is here formed by a solid rivet 11 fixed on the friction element 2. These balancing rivets have two heads 21 , 22 enclosing the friction element 2. One of the heads 22 is heavier than the other 21 of the heads. The heaviest rivet head 22 can be called a balancing head.

In FIG. 3, it can be seen that the axial length of the balancing rivet 11, in particular the axial length of its balancing head 22 is greater than the axial thickness of the web 8.

In FIG. 4, which represents the torque transmission device of FIG. 3, without the torque limiter 50, it can be seen that the guide washer 5 has, locally, a release of material. Here the circular outline of the washer 5 is locally gnawed in the form of a flat.

The three rivets 11 occupy part of the space left by this flat. Thus, the guide washer 5 can be lightened to reduce its inertia while maintaining the balancing rivets 11 at a satisfactory distance from the axis of rotation X.

According to a variant not shown, the balancing means can be blind rivets or rod breakage. According to another embodiment not shown, the balancing means 11 is an element welded to the friction element. According to another embodiment not shown, the balancing means 11 can be integrated into the friction element. If necessary, the balancing means can be a recess, for example a hole, or a machining of the friction element 2. Thus balancing the transmission device makes it possible to lighten the torque transmission device.

It can be seen in FIG. 3 that the friction element 2 comprises a fixing portion 13, the fixing portion 13 of the friction element 2 being fixed on a radially external zone of the damper input element 5 .

The fixing portion 13 of the friction element 2 is situated on a radially internal zone of the friction element 2 while the friction zone 3 is situated on a radially external zone of the friction element 2.

The balancing means 11 is arranged on an intermediate zone 16 of the friction element located radially between the fixing portion 13 and the friction zone 3 of the friction element 2.

In the embodiment presented in FIGS. 1 to 4, the friction element is a friction disc 2 which has an annular shape around the axis X. As a variant, the friction element 2 can comprise a plurality of circumferentially distributed blades around the X axis.

The friction disc 2 carries two linings 18, 19, carried by the friction zone 3 of the friction disc 2. The two linings are arranged on either side of the friction disc. If desired, this friction disc can have an axial progressiveness capable of exerting axial forces of elastic return opposing the pinching forces of the friction element.

The linings 18, 19 have an internal contour C3, and each balancing rivet 11 is arranged, in a plane comprising the axis of rotation X and passing through the balancing rivet, radially inside this internal contour C3 .

The support washer 51 and the reaction washer 53 have an internal contour C4, and a part of each balancing rivet 11 is arranged, in a plane comprising the axis of rotation X and passing through the balancing rivet, radially outside this inner contour C4.

FIG. 3 makes it possible to view the location of the balancing means within the assembly composed of the torque limiter 50, the friction disc 2 and the damper 4.

It can be seen in particular that the internal part of the support washer 51 and the internal part of the reaction washer 53 are separated axially by an annular space 58. The friction zone 3 of the friction element 2, the linings 18 and 19, the pressure washer 52, and the spring 55 are housed in this annular space 58. The support washer 51 and the reaction washer 53 each have an axial recess which makes it possible to create this annular space 58. The axial recess of the support washer 51 and the recess of the reaction washer 53 are oriented in two opposite axial directions so that the cavity is formed by these two axial recesses. The support washer 51 and the reaction washer 53 somehow form two covers axially opposite one another and delimiting this space or annular cavity 58.

The balancing rivet 11 is also partially arranged in this annular space 58. Thus, one can take advantage of this cavity 58, usually not used, to implant a balancing means which is fairly effective at this location relatively distant from the axis of rotation X.

As can be seen in FIG. 3, the balancing rivet 11 is arranged radially inside the pressure washer 52. There is a radial overlap between the pressure washer 52 and the balancing rivet 11, in particular between the balancing head 22 of the balancing rivet 11.

In a plane comprising the axis of rotation X and passing through the balancing rivet 11, the balancing rivet 11 is arranged radially between the web 8 and the pressure washer 52.

The balancing rivet 11 has an implantation axis A. This implantation axis A is located in the annular space 58 of the torque limiter 50.

The guide washer 5 has an external contour C1, and, in a plane P comprising the axis of rotation X and passing through the balancing rivet 11, the balancing rivet 11 is arranged radially outside the external contour C1 of the guide washer 5.

The damper 4 has an external contour C2, defined here by the external contour of the web 8 and the balancing rivet 11 is arranged, in a plane P comprising the axis of rotation X and passing through the balancing rivet 11, radially outside this contour C2.

This implantation of the balancing means offers, in addition to its radial distance with the axis X, great freedom of shape for the balancing means, in particular as regards the axial length of the balancing means.

Thus, for comparison, the axial length of the balancing rivet 11, and in particular its balancing head 22, can be greater than the axial thickness of the web 8. The axial length of the balancing rivet 11, and in particular its balancing head 22, may be greater than the axial thickness of the assembly composed of the friction element 2 and the linings 18 and 19. The axial length of the balancing rivet 11 may be greater than the axial thickness of the assembly composed of the friction element 2, the linings 18 and 19, and the pressure washer 52.

Figures 5 and 6 illustrate an example of a balancing rivet presented before mounting (Figure 5) and in the assembled state (Figure 6). It can be seen that the entire mass of the balancing rivet 11 can be placed essentially on one of the two heads, in particular on the head 22 which is not deformed during assembly.

FIG. 7 is a schematic view of another embodiment in which the guide washer 5 has, in a plane perpendicular to the axis X, a wavy outline around the axis X.

The wavy outline has a plurality of ridges 68 arranged circumferentially, a hollow 69 being arranged between two neighboring ridges 68.

The friction element is produced here by a plurality of blades 2 distributed around the axis X. The blades 2 are fixed to the guide washer 5 by rivets 67 arranged at the level of these ridges 68 which have been previously drilled. To do this, each blade 2 has a blade leg 2a which axially covers two ridges 68 of the guide washer 5.

The balancing means is fixed on the blade foot 2a and part of the balancing means 11 is arranged circumferentially between two ridges 68 adjacent to the guide washer 5. As before, the balancing means 11 may be a rivet. Several balancing rivets can be used if necessary.

The crests 68 have an extremum defining an outer crest diameter DC and the balancing means 11 can be arranged at least partially inside this diameter DC. Thus, this solution makes it possible to reduce the inertia of the guide washer 5 while keeping the balancing means fairly far from the axis X.

Figure 8 is a perspective view of a third embodiment which differs from the first embodiment in that the balancing means 11 can be located on the periphery of the friction disc 2. The friction disc 2 comprises implantation holes 88 regularly distributed around the axis of rotation X. Depending on the balancing needs, in particular as a function of the unbalance phenomena observed, a hole 88 or certain holes 88 will be provided with a balancing means such as a balancing rivet 11.

The invention is particularly advantageous when it is desired to have implantation points regularly distributed, in particular in comparison with the solutions of the prior art in which the implantation points are on the guide washer because a regular distribution of the implantation points on the guide washers is difficult due to the presence of spacers 31, springs 10 ...

Figure 9 is a sectional view of another embodiment having an assembly as described above mounted on a flywheel.

As before, the support washer 51 and the reaction washer 53 each have a mounting portion 56 and 57. These mounting portions 56 and 57 are each provided with orifices. The orifices of the mounting portions 56 and 57 of the support washer 51 and of the reaction washer 53 are concentric so that the same screw is introduced both into the support washer and into the reaction washer. These screws therefore allow the attachment of the assembly consisting of the torque transmission device 1 and the torque limiter 50 to the flywheel. This is a flexible flywheel 90, especially axially.

The support washer 51 and the reaction washer 53 are preferably preassembled, in particular by means of rivets 92 arranged on the mounting portions 56, 57 of the support washer 51 and the reaction washer 53.

The transmission assembly 100 further comprises a pendulum shock absorber 70. The use of a balancing means 11 proves to be particularly useful when a pendulum shock absorber 70 is used because the pendulum shock absorber 70 can generate an unbalance phenomenon .

The pendulum shock absorber 70 comprises a pendulum support 71 rotatable around the axis of rotation. The pendulum shock absorber 70 is centered on the hub 28 by means of its pendulum support 71. The pendulum support 71 can be mounted integral in rotation with the hub 28, for example by force mounting, or by means of splines.

The pendulum damper 70 comprises a plurality of pendulum masses 72, able to move freely in a plane perpendicular to the axis X relative to the pendulum support 71 and guided by this same pendulum support 71.

Each pendulum mass 72 is mounted on the external periphery of the pendulum support 71 and comprises two parts 72a and 72b mounted axially on either side of the pendulum support 71 and connected together by one or more spacers 73 each passing through an opening of the pendulum support 71 A roller (not visible in FIG. 9) cooperates with a raceway formed in each spacer 73 and with the edge of the corresponding opening of the pendulum support 71. This type of pendulum damper is already known.

Thus, in reaction to torsional oscillations or rotational acyclisms, each pendulum mass 72 moves so that its center of gravity oscillates pendulum. Each pendulum mass 72 is thus animated in the operation of a pendulum movement.

It can be seen in FIG. 7 that the pendulum masses 72 and the friction zone of the friction disc 2 are axially offset.

In the plane P of FIG. 9 comprising the axis of rotation X and passing through the balancing means 11, the balancing means is arranged radially beyond the internal radial edge b1 of the pendulum masses 72.

Preferably, there is an axis parallel to the axis of rotation passing through both the pendulum mass 72 and the balancing means 11. The balancing means 11 and the pendulum mass 72 are therefore axially opposite one of the other.

By way of comparison, the axial length of the balancing means is greater than the axial thickness of the pendulum 70 in the area of the masses 72.

In the three embodiments described above, the damper input element is a guide washer. The invention also applies to an inverted architecture in which the damper input element is the web and the damper output output element is the guide washer (s).

Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these are within the scope of the invention.

In particular, although the invention is described above in relation to a torque limiter, the invention is not limited to such an embodiment and the friction mechanism can also be a clutch mechanism capable of pinch, in an engaged mode the friction element and able to release, in a disengaged mode, the friction element.

Similarly, the pendulum support can be mounted directly on the shock absorber outlet element, in particular the veil. This pendulum support can be fixed to the torque output element so that the pendulum support and the torque output element are rotatably attached at least up to a certain torque value.

The use of the verb "comprise", "understand" or "include" and its conjugated forms does not exclude the presence of other elements or steps than those set out in a claim.

In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims (13)

1. Torque transmission device (1) for a motor vehicle powertrain, comprising: a friction element (2) movable in rotation about an axis of rotation X, the friction element comprising a friction zone (3) capable of being pinched by a torque transmission mechanism (50), - a shock absorber (4) comprising a shock absorber input element (5), a shock absorber output element (8), at least one spring (10) being arranged between the shock absorber input element ( 5) and the shock absorber output element (8) so as to compress to filter acyclisms, and the friction element (2) being fixed to the shock absorber input element (5), - at least one balancing means (11), characterized in that, in a plane (P) comprising the axis of rotation X and passing through the balancing means, the balancing means (11) is arranged radially between the shock absorber input element (5) and the friction zone (3). 2. Torque transmission device according to claim 1 wherein the torque transmission device comprises a plurality of balancing means (11) and each balancing means is arranged, in a plane comprising the axis of rotation X and passing through this balancing means, radially between the damper input element (5) and the friction zone (3). 3. Torque transmission device according to one of the preceding claims in which the balancing means (11) is arranged on the friction element (2). 4. Torque transmission device according to the preceding claim wherein the balancing means (11) is only connected to the friction element (2). 5. Torque transmission device according to one of claims 1 to 4 wherein the balancing means (11) is integrated with the friction element (2). 6. Torque transmission device according to the preceding claim wherein the balancing means is a recess in the friction element (2). 7. Torque transmission device according to one of claims 1 to 5 wherein the balancing means (11) is an element adding mass locally to a part of the torque transmission device (1), in particular a part of the friction element (2). 8. Torque transmission device according to the preceding claim wherein the balancing means is a rivet (11). 9. Torque transmission device according to the preceding claim wherein the balancing means is a rivet with two heads (21, 22) enclosing the friction element (2), one of the heads (22) being heavier than the other (21) of the heads. 10. Torque transmission device according to one of the preceding claims, in which the damper input element (5) has, in a plane perpendicular to the X axis, a wavy outline around the X axis, the wavy contour having at least two ridges (68) arranged circumferentially on either side of a recess (95), at least part of the balancing means (11) being arranged circumferentially between two ridges (68) of l shock absorber input element (5). 11. Torque transmission device according to one of the preceding claims, in which the friction element (2) carries at least one lining (18, 19)), said at least one lining (18, 19) being carried by the friction zone (3) of the friction element (2), said at least one lining (18, 19) having an internal contour (C3), and each balancing means (11) is arranged radially inside of this interior contour (C2). 12. Transmission device according to one of claims 1 to 11 comprising a pendulum shock absorber (70), the pendulum shock absorber comprising a pendulum support (71) mounted integral in rotation with the shock absorber output element (8). 13. Transmission assembly (100) comprising: a transmission device (1) according to one of the preceding claims, - a pressure mechanism (50) arranged to pinch the friction element (3) permanently or temporarily at said at least one friction zone (3). the pressure mechanism being a torque limiter (50) comprising: - a support washer (51), - a pressure washer (52), - a reaction washer (53), the friction element (2) being arranged axially between the pressure washer (52) and the reaction washer (53), - a spring (55) arranged between the support washer (51) and the pressure washer (52) so as to press the pressure washer (52) against the friction zone (3) so that the friction zone (3) either pinched by the pressure washer (52) and the reaction washer (53). the torque limiter (50) comprising an annular space (58) axially separating the support washer (51) and the reaction washer (53) and in which the pressure washer (52), the spring (53) and the friction zone (3) of the friction element (2) are arranged, the balancing means (11) being also arranged at least partly in this annular space (58).