FR3056273A1 - TORSION DAMPER AND TORQUE TRANSMISSION DEVICE COMPRISING SUCH DAMPER - Google Patents

Abstract

The invention relates to a torsion damper (1) for a torque transmission device comprising: - a first element (3) and a second element (4) movable in rotation relative to each other about an axis of rotation X between a first position called rest position and a second position called abutment position, - damping means for transmitting a torque and damping rotation acyclisms between the first element and the second element, characterized in that: the first (3) and the second (4) elements comprise at least two abutment walls (28A), an abutment wall (28A) of the first element (3) being configured to come into contact with an abutment wall (43A ) respectively of the second element (4) in the second position, and in that at least one recess (40, 45, 45 ') is provided at at least one of the abutment walls (28A) to allow creep of material to the recess (40) during a contact between the prem ier (3) and the second (4) element.

Description

Technical area

The invention relates to the field of torque transmission devices of the torsion damper type intended to equip motor vehicle transmissions.

Technological background

Explosion engines do not generate constant torque and exhibit acyclisms caused by successive explosions in their cylinders. These acyclisms generate vibrations which are liable to be transmitted to the gearbox and thus to generate shock, noise and noise, which are particularly undesirable. In order to reduce the undesirable effects of vibrations and improve the driving comfort of motor vehicles, it is known to equip motor vehicle transmissions with torsional dampers. Such torsional dampers are fitted in particular to double-damped flywheels (DVAs), clutch friction, or locking clutches, also called "lock-up" clutches.

The document FR3008152 discloses a double damping flywheel comprising a primary flywheel and a secondary flywheel which can rotate relative to one another about an axis of rotation X. The double damping flywheel comprises means cushioning elastic between the primary flywheel and the secondary flywheel. These elastic damping means are for example produced by helical springs or flexible blades.

Document FR3008152 also discloses the use of stops to limit the angular movement between the primary flywheel and the secondary flywheel and thus avoid damaging the elastic damping means. The torsion damper generally comprises at least two diametrically opposite stops to avoid a mechanical imbalance of the torsion damper when the primary flywheel abuts against the secondary flywheel.

However, due to the tolerances in the machining of the stops, it sometimes happens that the contact between the primary flywheel and the secondary flywheel is made only at one of the stops, which causes material to droop at the walls. of active stops. Such material loss can cause material to flow towards the inside of the flywheels, which can lead to deterioration of the torsion damper and in particular elastic damping means.

It is therefore advisable to find a solution making it possible to avoid a slackening of material and a deformation of the abutment wall which could harm the functioning of the torsion damper.

summary

The invention aims to provide a torsional damper in which the direction of the creep of the abutment walls is controlled to avoid a backflow of material in a direction which could adversely affect the functioning of the torsional damper.

To this end, the present invention describes a torsional damper for a torque transmission device comprising:

a first element and a second element movable in rotation with respect to each other about an axis of rotation X between a first position called the rest position and a second position called the stop position,

a damping means for transmitting a torque and damping the rotation acyclisms between the first element and the second element, in which:

- The first and second elements comprise at least two stop walls, a stop wall of the first element being configured to come into contact with a respective stop wall of the second element in the second position, and in that at least one a recess is provided at at least one of the abutment walls to allow material to flow towards the recess during contact between the first and the second element.

The presence of a material recess at the abutment walls makes it possible to control the direction of the material creep due to impacts between the material abutment walls to avoid material creep in a direction which may affect the operation of the damper of torsion.

According to one aspect of the present invention, the recess is produced in the form of a groove made at the level of the at least one abutment wall.

According to another aspect of the present invention, the, at least one abutment wall extends in a substantially radial direction relative to the axis of rotation X and the groove is formed at the base of the abutment wall and s' also extends in a substantially radial direction relative to the axis of rotation X.

According to one aspect of the present invention, the groove defines an edge of said at least one abutment wall.

According to one aspect of the present invention, when said abutment wall is in contact with the respective abutment wall, the groove also borders the respective abutment wall.

According to one aspect of the present invention, the groove extends radially along said at least one abutment wall.

According to one aspect of the present invention, at least part of the recess is arranged in the radial space occupied by said at least one abutment wall. The recess then extends essentially at a distance from the end of the abutment wall situated towards the axis of the torsion damper.

In this way, it is avoided that too much excess material flows radially beyond the abutment wall, in particular radially inside the abutment wall.

According to a further aspect of the present invention, the recess is produced by grooves formed in the abutment wall.

According to an additional aspect of the present invention, the grooves extend in the direction of the machining of the abutment wall.

According to another aspect of the present invention, the grooves extend in a radial direction or in an axial direction.

According to an additional aspect of the present invention, the grooves formed in the, at least one, abutment wall of the first element has a different orientation from the grooves formed in the, at least one, abutment wall of the second element.

According to a further aspect of the present invention, the stop walls are made of cast iron or steel.

According to another aspect of the present invention, the stop walls extend in a substantially radial direction relative to the axis of rotation X.

According to one embodiment, several recesses are formed at the level of said at least one abutment wall.

According to one aspect of the invention, the walls adjacent to the at least one abutment wall form an angle of at least 20 ° with said at least one abutment wall and extend on the same side of the plane defined by said at least one abutment wall so that said at least one abutment wall projects in relation to the adjacent walls.

According to one aspect of the invention at least one recess is provided at the respective abutment wall to allow a flow of material towards this recess during contact between the first and the second element.

According to one embodiment, several recesses are formed at the level of said at least one respective abutment wall.

According to one aspect of the invention, the walls adjacent to the at least one respective abutment wall form an angle of at least 20 ° with said respective abutment wall and extend on the same side of the plane defined by said respective abutment wall so that said at least one respective abutment wall projects.

According to an additional aspect of the present invention, the torque transmission device is a device with double damping flywheel.

According to a further aspect of the present invention, the damping means is a blade damping means comprising at least one blade integral with one of said first and second elements and in which the torsional damper also comprises at least one cam follower carried by the other of said first and second elements, or disposed between the first and second element, and arranged to cooperate with a cam surface of said at least one blade, said at least one blade being arranged in such a way that, for an angular movement between the first and second elements relative to the rest position, said at least one cam follower exerts a bending force on said at least one blade jointly producing a reaction force capable of recalling the first and second elements towards said rest position.

The present invention also relates to a torque transmission device, in particular for a motor vehicle, comprising a torsion damper as described above.

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 schematic sectional view of a torsion damper comprising a double damping flywheel with flexible blades;

- Figure 2 is a schematic perspective view of a primary flywheel according to a first embodiment;

- Figure 3 is an enlarged view of a portion B of Figure 2;

- Figure 4 is a schematic perspective view of a secondary flywheel according to the first embodiment;

- Figure 5 is an enlarged view of a portion C of Figure 4;

- Figure 6 is a schematic perspective view of the primary and secondary flywheels in the assembled state;

- Figure 7 is an enlarged view of a portion A of Figure 6;

- Figure 8 is a schematic perspective view of a primary flywheel according to a second embodiment;

- Figure 9 is an enlarged view of a portion B of Figure 8;

- Figure 10 is a schematic perspective view of a secondary flywheel according to a first alternative of the second embodiment;

- Figure 11 is an enlarged view of a portion C of Figure 10;

- Figure 12 is a schematic perspective view of a secondary flywheel according to a second alternative of the third embodiment;

- Figure 13 is an enlarged view of a portion C of Figure 12.

Detailed description of the 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 assembly for the torque transmission device. By convention, the radial orientation is directed orthogonally to the axis X of rotation of the assembly for the torque transmission device 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 assembly for the torque transmission device and orthogonally to the radial direction. Thus, a component described as developing circumferentially is a component of which a component develops in a circumferential direction. The terms external and internal are used to define the relative position of one component with respect to another, with reference to the axis of rotation of the torque transmission device, a component close to the axis is thus qualified as internal as opposed to an external component located radially on the periphery. Finally, the terms rear and front are used to define the relative position of one component with respect to another along the axial orientation, a component located close to the engine being qualified as before with respect to a component further from the motor along the axial orientation, the latter component being termed rear.

The following description is made with reference to the figures in the context of a torque transmission device of the double damping flywheel type. This description is not limiting and the invention is applicable by analogy to any other type of torque transmission device comprising a torsion damper.

A torsion damper comprises a first so-called input element and a second so-called output element which are arranged, in the transmission chain, respectively on the internal combustion engine side and on the gearbox side. By way of example, the torsional damper can be a double damping flywheel, the input element being constituted by a first flywheel said primary flywheel intended to be fixed at the end of a driving shaft , such as the crankshaft of an internal combustion engine, while the output element is constituted by a second flywheel said secondary flywheel forming, in general, reaction plate of a coupling clutch to a driven shaft, such as the input shaft of a gearbox.

The input and output elements are mounted movable in rotation by means of a bearing about a common axis of rotation X. The input and output elements have a respectively internal and external hub. The bearing is inserted radially between the inner hub and the outer hub.

The input element and the output element are coupled in rotation by damping means. In the following description, these damping means comprise two elastic blades carried by one of the input element and the output element. These elastic blades each have a cam surface cooperating with a cam follower carried by the other among the input element and the output element. The damping means are thus able to transmit a driving torque from the input element to the output element (direct direction) and a resistive torque from the output element to the input element (retro direction ). On the other hand, the elastic blades develop an elastic return torque tending to return the input element and the output element to a relative angular position of rest. The document FR3008152 describes the general operation of such a blade torsion damper.

However, the present invention is not limited to torsion dampers whose damping means are with blades but also extends to other types of torsion damper such as for example torsion dampers comprising helical springs. The invention also extends to torque transmission devices comprising such torsional dampers.

FIG. 1 represents a view in radial section of a part of a torsion damper 1 comprising a first element corresponding to a primary flywheel 3 on which two cam followers are mounted in the form of rollers 6 mounted movably in rotation and a second element corresponding to a secondary flywheel 4 on which two flexible blades 2 are assembled, a roller 6 being intended to cooperate with an associated flexible blade 2. The primary flywheel 3 and the secondary flywheel 4 are mounted movable around the axis X which is perpendicular to the plane of Figure 1. With regard to the secondary flywheel 4, only part of the hub 5 ' and the protrusions 41 forming stops are visible in FIG. 1.

The primary flywheel 3 also includes two circumferential recesses 26 delimited by two projections 39. The circumferential recesses 26 are arranged symmetrically with respect to the axis X and extend over a predetermined angular section, for example 120 °. The walls of the projections 39 delimiting the circumferential withdrawal 26 extend substantially radially and form a first 28A and a second 28B abutment walls intended to cooperate with the secondary flywheel 4 to limit the angular movement between the primary flywheel 3 and the secondary flywheel 4. A third 28C and a fourth 28D stop walls can also be used to cooperate with the secondary flywheel 4 in a second stop position.

The two flexible blades 2 are for example fixed on the secondary flywheel 4 by means of three rivets 11 arranged in through holes called "riveting holes" formed in a mounting portion 7 of the blade 2.

The blades 2 have for example a hairpin shape and comprise a transmission portion 8 located at a first end of the blade 2 on which is located a cam surface 10 intended to cooperate with a cam follower produced in the form a roller 6, the mounting portion 7 located at a second end which allows the blade 2 to be fixed on the secondary flywheel 4 and an angled portion 9 connecting the transmission portion 8 and the mounting portion 7.

Thus, in operation, the relative rotation of the primary flywheel 3 relative to the secondary flywheel 4 causes the roller 6 to move along the cam surface 10 of the transmission portion 8 of the blade 2. During this movement, the roller 6, pivotally mounted, rolls on the cam surface 10. This movement of the roller 6 causes the blade to bend 2. This bending produces a resistant torque of the blade 2 on the roller 6 which tends to move the roller 6 in the direction reverse, that is to say so as to return to the angular position of rest.

In the present example, the roller 6 forming the cam follower is carried by the primary flywheel 3 by means of a rod fixed to the primary flywheel. Alternatively, the cam follower can be produced by a free roller held between the blade 2 and the peripheral wall of the primary flywheel 3. In this case, the roller is able to roll along a raceway corresponding to the peripheral wall of the primary flywheel 3 in order to be able to complete a curvilinear path over at least one angular sector, the curvilinear movement of this roller relative to the primary flywheel 3 being accompanied by a movement of this roller on the surface cam of the elastic blade 2, in particular while rolling, and causing it to flex (see patent application FR3032248).

The secondary flywheel 4 comprises two abutment protrusions 41 comprising a first 43A and a second 43B abutment walls which extend substantially radially and are configured to come into contact respectively with the first 28A and second 28B abutment walls of the projections 39 of the flywheel primary 3 in the stop position. The secondary flywheel 4 can also include a third 43C and a fourth 43D abutment walls configured to come into contact respectively with the first 28C and second 28D abutment walls of the projections 39 of the primary flywheel 3 in a second abutment position

FIG. 1 represents an abutment position of the torsion damper 1 in which the respective abutment walls of the projections 39 and the abutment protrusions 41 are in contact. Such a stop position makes it possible to limit the relative rotation of the primary flywheel 3 and of the secondary flywheel 4 so as in particular not to damage the damping means such as the blades 2.

In addition, at least one recess 40, 40 ', 45, 45' of material is provided at at least one of the abutment walls 28A ... 28D, 43A ... 43D to direct the

The different abutment walls 28A ... 28D of the primary flywheel 3 and

43A ... 43D of the secondary flywheel 4 are for example made of cast iron or steel and have a substantially square or rectangular section of approximately 40 mm ² .

material creep towards this recess 40, 40 ', 45, 45'. The various embodiments of a recess 40, 40 ', 45, 45' will now be described in detail.

1) Recess produced in the form of a groove 40, 40 '

FIG. 2 represents a schematic perspective view of a primary flywheel 3 according to a first embodiment. FIG. 3 represents an enlarged view of the portion B of FIG. 2.

The primary flywheel 3 comprises a central hub 5 from which an annular plate 51 extends. A flange 53 extends along the circumference of the annular plate 51 and has a predefined height along the axis X. Four openings 55 are provided in the collar 53 so that the collar 53 is divided into four parts. The role of the opening 55 is to facilitate the machining of the recess here in the form of a groove 40 and to allow the material to flow outwards. It can be seen here that the walls adjacent to the stop walls 28 form an angle of at least 20 ° with the stop walls 28 and are located on the same side with respect to the plane of the stop walls so that the stop walls stand out from the adjacent walls. Thus, the creep of material is possible, in particular on the side of the groove 40 and the opening 55.

First parts forming circumferential edges 57 and extending over a predetermined angular section, for example 120 ° and second parts forming the projections 39. Axial holes 60 are for example formed in the projections 39 and are intended to receive the rollers 6. In addition, the radial width of the circumferential edges 57 is less than the radial width of the projections 39, thus forming the two circumferential recesses 26 described from FIG. 1.

As is better visible in FIG. 3, the first abutment wall 28A of the projection 39 may have a material recess in the form of a groove 40. The groove 40 may be formed on an edge of the abutment wall, in particular at the base of the first abutment wall 28A. The groove 40 has for example a semi-cylindrical shape with a diameter between 2 and 6 mm, for example 4 mm and extends in a substantially radial direction. The groove 40 extends radially along the abutment wall 28A. The groove therefore extends essentially at a distance from the internal end of the abutment wall 28A, that is to say from the edge situated on the internal side of the abutment wall 28A. This groove 40 makes it possible to control the flow of material produced when the abutment projection 41 of the secondary flywheel 4 comes into contact with the first abutment wall 28A of the projection 39. Indeed, the deformation of material, also called matting, produced by the shocks produced when the abutment wall 43A of the abutment protrusion 41 comes into contact with the abutment wall 28A of the projection 39 causes a flow of the material from the abutment wall 28A towards the groove 40. The groove 40 thus makes it possible to avoid a flow of material towards the axis X which could lead to degradation of the blades 2 in particular. The volume of the groove 40 is large enough to accommodate, on the one hand, the material displaced during the first flows mainly occurring on one of the abutment walls (due to the machining tolerances) during the first abutments, and on the other hand the material displaced by creep during the subsequent abutments, which, after balancing resulting from the first abutments, are they simultaneous at the level of the various abutment walls.

Likewise, a groove 40 is formed on the second abutment wall 28B of the second projection 39. Similarly, grooves 40 can also be formed at the third 28C and fourth 28D stops.

FIG. 4 represents a schematic perspective view of a secondary flywheel 4 according to the first embodiment. FIG. 5 represents an enlarged view of the portion C of FIG. 4.

The secondary flywheel 4 includes a hub 5 'from which an annular plate 51' develops radially outward. The hub 5 ′ is intended to carry a bearing 30 ensuring the mounting in rotation of the secondary flywheel 4 and of the primary flywheel 3, for example via a ball bearing. In the context of a double damping flywheel, the annular plate 51 ′ forms, on a face opposite to the primary flywheel 3, a bearing surface for a friction lining of a clutch disc (not shown) . Two abutment protrusions 41 extend in an arc of a circle in an area close to the periphery of the annular plate

51 '. The two abutment protrusions 41 extend over a predetermined angular portion, for example 60 °. The abutment protrusions have a predetermined height along the axis X. At the circumferential ends of the abutment protrusions 41 are the abutment walls 43A, 43B, 43C and 43D intended to cooperate respectively with the abutment walls 28A, 28B, 28C and 28D of the primary flywheel 3. In the stop position, the groove 40 borders not only the stop walls 28A, 28B, 28C and 28D but also the respective stop walls 43A, 43B, 43C and 43D.

As is better visible in FIG. 5, the first abutment wall 43A of the abutment protrusion 41 may have a material recess in the form of a groove 40 '. The groove 40 'can be formed at the base of the first abutment wall 43A. The groove 40 'has for example a semi-cylindrical shape with a diameter between 2 and 6 mm, for example 4 mm and extends in a substantially radial direction. This groove 40 'makes it possible to control the matting of material produced when the first abutment wall 28A of the projection 39 comes into contact with the first abutment wall 43A of the abutment projection 41 of the secondary flywheel 4.

Similarly, a groove 40 ′ is formed at the level of the second abutment wall 43B of the second abutment projection 41. Similarly, grooves 40 ′ can be formed at the level of the third 43C and fourth 43D abutment walls of the secondary flywheel 4.

As for the primary flywheel 3 described above, the grooves

40 'formed in the stop walls 43A ... 43D of the secondary flywheel 4 make it possible to control the creep of the stop walls 43A ... 43D of the secondary flywheel 4 due to the mating when the stop walls 28A ... 28D of the primary flywheel 3 respectively come into contact with the abutment walls 43A ... 43D of the secondary flywheel 4.

FIG. 6 represents a schematic perspective view of the primary flywheel 3 and of the secondary flywheel 4 in the assembled state via a bearing

30 according to the first embodiment. FIG. 7 represents an enlarged view of the portion A of FIG. 6. In these FIGS. 6 and 7, the torsion damper 1 is in an abutment position so that the first abutment wall 28A of a projection 39 is in contact with the first abutment wall 43A of an abutment projection 41. The groove 40 of the abutment wall 28A of the primary flywheel 3 is located on a first side of the first abutment walls 28A and 43A while the groove 40 'of the abutment wall 43A of the secondary flywheel 4 is located on a second side of the first abutment walls 28A and 43A. In FIGS. 6 and 7, the secondary flywheel 4 is located above the primary flywheel 3 so that the first abutment wall 43A of the secondary flywheel 4 is oriented downwards and the groove 40 'is located above the first abutment wall 43A while the first abutment wall 28A of the primary flywheel 3 is oriented upwards and the groove 40 is located below the first abutment wall 28A . The first two abutment walls 28A and 43A extend in a radial direction and are therefore mutually parallel at the level of the contact. Thus, during the repetition of impacts, the material creep takes place towards the grooves 40 and 40 'formed on each of the first abutment walls 28A and 43A, which makes it possible to control the direction of this creep.

The use of a recess 40, 40 ′ at the level of at least one abutment wall therefore makes it possible to control the direction in which the creep is made and thus avoid creep in an unwanted direction which could lead to a malfunction. or even damage to the torsional damper 1.

In addition, in the case where the manufacturing tolerances, in particular machining, lead to the fact that only the first abutment walls 28A and 43A or only the second abutment walls 28B and 43B come into contact with one another in the stop position of the torsion damper 1, the material flow allows after a predetermined time of use of the torsion damper 1, that is to say after the first abutments, to catch up with the manufacturing tolerances and allow simultaneous contact of the first 28A, 43A and second 28B, 43B abutment walls. This predetermined time is relatively limited compared to stop walls without material recess. In the same way, the flow of material at the level of the third 28C, 43C and fourth 28D, 43D abutment walls makes it possible to make up for any angular offset relating to the contacting of the two pairs of abutment walls 28C, 43C and 28D, 43D .

Alternatively, a groove 40 or 40 ′ can be provided only at the level of certain abutment walls of the primary flywheel 3 and / or of the secondary flywheel 4.

2) Obviously produced in the form of grooves 45, 45 '

FIG. 8 represents a schematic perspective view of a primary flywheel 3 according to a second embodiment. FIG. 9 represents an enlarged view of the portion B of FIG. 8.

In this embodiment, the recess is produced by grooves 45 formed at the abutment walls of the primary flywheel 3. The grooves have for example a form of slots or a sinusoidal shape. The depth and width of the grooves 45 are for example between 2 and 8 mm. The grooves 45 can be regular or irregular. Figure 9 shows in particular the first abutment wall 28A on which the grooves 45 extend in a substantially radial direction. Preferably, the grooves 45 are oriented in the direction of machining to facilitate the manufacturing process of the primary flywheel 3. Of course, other orientations of grooves 45, in particular axial can be used. The grooves 45 may extend over the entire surface of the first abutment wall 28A as shown in FIG. 9 or only over certain portions. Similarly, grooves 45 are formed at the second abutment walls 28B or even the third 28C and fourth 28D abutment walls. In this embodiment, the abutment walls 28A ... 28D do not have a groove 40.

The primary flywheel 3 is also identical to the primary flywheel 3 of the first embodiment.

a) Secondary flywheel 4 without groove

According to a first sub-embodiment shown in FIGS. 10 and

11, the secondary flywheel 4 comprises substantially smooth abutment walls 43A ... 43D, that is to say the roughness of which is less than 1mm.

Thus, the smooth stop walls 43A ... 43D of the secondary flywheel 4 are configured to come into contact with the grooved stop walls 28A ... 28D, that is to say provided with grooves 45, the primary flywheel 3. Thus, in the event of matting, the material creeps towards the hollows of the grooves 45 of the abutment walls 28A ... 28D of the primary flywheel 3. In addition, as in the case of the first embodiment, the grooves 45 can not only make it possible to control the direction of the flow of material but can also make it possible to make up for the manufacturing tolerances to allow simultaneous contact of the first and second abutment walls of the primary flywheel 3 and the secondary flywheel 4 after a limited operating time of the torsion damper 1.

Alternatively, the abutment walls 28A ... 28D of the primary flywheel 3 can be smooth and only the abutment walls 43A ... 43D can include splines 45 as described above.

b) Secondary flywheel 4 with 45 'splines

According to a second sub-embodiment shown in FIGS. 12 and 13, the abutment walls 28A ... 28D of the secondary flywheel 4 also include splines 45 '. These grooves 45 ′ have a different orientation from the grooves 45 of the respective stop walls of the primary flywheel 3. Preferably, the direction of the grooves 45 ′ of a stop wall of the secondary flywheel 4 form an angle 90 ° with the direction of the splines 45 of the associated abutment wall of the primary flywheel 3 (when the abutment walls are in contact in the assembled state of the torsion damper). In the present case, the splines 45 of the first abutment wall 28A of the primary flywheel 3 being substantially radial (see FIG. 9), the splines 45 'of the first abutment wall 43A of the secondary flywheel 4 are oriented in an axial direction. The splines 45 'have for example dimensions similar to the splines 45 of the stop walls 28A ... 28D of the primary flywheel 3 and can extend over the entire surface of the first stop wall 43A of the flywheel secondary 4.

In the same way, the other abutment walls 43B ... 43D may include splines 45 'with a different orientation from the splines 45 of the abutment wall 28B ... 28D associated with the primary flywheel 3.

The use of splines 45 ′ on the abutment walls 43A ... 43D of the secondary flywheel 4 makes it possible to reinforce the control of the material creep. Indeed, the material flows towards the grooves 45 ′ in the event of matting with the abutment wall of the primary flywheel 3.

Thus, the use of a material recess, for example in the form of a groove or grooves, at the level of the abutment walls of a torsion damper 1 makes it possible to control and direct the flow of material to avoid slackening of material towards the inside of the torsion damper 1. In addition, in the case of a torsion damper 1 comprising several stops intended to act simultaneously, this controlled flow of material can make it possible to make up for manufacturing tolerances at the level abutment walls so as to allow simultaneous contact of the different abutments without risking causing deterioration of the torsional damper 1.

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 these are within the scope of the invention.

For example, the number of blades mounted on the element can be variable as well as the number of blade fixing rivets. Similarly, the element on which the blades are mounted can be any other type of input or output element of a torsion damper.

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

Claims (11)

1. Torsional damper (1) for a torque transmission device comprising: - a first element (3) and a second element (4) movable in rotation relative to each other about an axis of rotation X between a first position called the rest position and a second position called the stop position , a damping means (2) for transmitting a torque and damping the rotational acyclisms between the first element and the second element, characterized in that: - the first (3) and the second (4) element comprise at least two stop walls (28A, 28B, 28C, 28D, 43A, 43B, 43C, 43D), a stop wall (28A, 28B, 28C, 28D ) of the first element (3) being configured to come into contact with a respective abutment wall (43A, 43B, 43C, 43D) of the second element (4) in the second position, and in that at least one recess (40 , 45, 45 ') is provided at at least one of the abutment walls (28A, 28B, 28C, 28D, 43A, 43B, 43C, 43D) to allow a flow of material towards the recess (40, 45 , 45 ') during a contact between the first (3) and the second (4) element. 2. torsion damper (1) according to claim 1 wherein the recess (40, 45, 45 ') is made in the form of a groove (40) formed at the, at least one, abutment wall (28A, 28B, 28C, 28D, 43A, 43B, 43C, 43D). 3. Torsional damper (1) according to claim 2 wherein the at least one abutment wall (28A, 28B, 28C, 28D, 43A, 43B, 43C, 43D) extends in a substantially radial direction relative to the axis of rotation X and the groove (40) is formed at the base of the stop wall (28A, 28B, 28C, 28D, 43A, 43B, 43C, 43D) and also extends in a substantially radial direction by relative to the axis of rotation X. 4. torsion damper (1) according to claim 1 wherein the recess (40, 45, 45 ') is produced by grooves (45, 45') formed in the abutment wall (40, 45, 45 ’). 5. Torsional damper (1) according to claim 4 wherein the grooves (45, 45 ') extend in the direction of machining of the abutment wall (28A, 28B, 28C, 28D, 43A, 43B, 43C, 43D). 6. Torsional damper (1) according to claim 4 or 5 wherein the grooves (45, 45 ') extend in a radial direction or in an axial direction. 7. torsion damper (1) according to claim 4 or 6 wherein the grooves (45) formed in the, at least one, abutment wall (28A, 28B, 28C, 28D) of the first element (3) has an orientation different from the grooves (45 ') formed in the, at least one, abutment wall (43A, 43B, 43C, 43D) of the second element (4). 8. Torsional damper (1) according to one of the preceding claims wherein the stop walls (28A, 28B, 28C, 28D, 43A, 43B, 43C, 43D) are made of cast iron or steel. 9. Torsional damper (1) according to one of the preceding claims wherein the torque transmission device is a double flywheel damping device. 10. torsion damper (1) according to claim 9 wherein the damping means is a damping means with a blade (2) comprising at least one blade integral with one of said first (3) and second (4) elements and in which the torsion damper (1) also comprises at least one cam follower (6) carried by the other of said first (3) and second (4) elements or arranged between the first and the second element and arranged to cooperate with a cam surface (10) of said at least one blade (2), said at least one blade (2) being arranged such that, for an angular movement between the first (3) and second (4) elements relative to the rest position, said at least one cam follower (6) exerts a bending force on said at least one blade (2) jointly producing a reaction force capable of recalling the first (3) and second ( 4) elements towards the said rest position. 11. Torque transmission device, in particular for a motor vehicle, comprising a torsion damper (1) according to one of the preceding claims. 1/7