WO2016050593A1

WO2016050593A1 - Damper, in particular for a motor vehicle clutch

Info

Publication number: WO2016050593A1
Application number: PCT/EP2015/071918
Authority: WO
Inventors: Jérôme BOULET; Daniel Fenioux; Carlos Lopez-Perez
Original assignee: Valeo Embrayages
Priority date: 2014-10-01
Filing date: 2015-09-23
Publication date: 2016-04-07
Also published as: FR3026800A1; FR3026800B1; EP3201488A1

Abstract

The invention relates to a damper (1), in particular for a motor vehicle clutch, said damper comprising: an input element; an output element that can rotate in relation to the input element about a rotation axis (X); and damping means disposed between the input and output elements, said damping means comprising a spring plate (17a, 17b) mounted on either the input element or the output element and disposed between said elements such as to bend and transmit a torque from the input element to the output element or vice versa. In a first operating phase, variations in the transmitted torque are accompanied by a relative rotation between the input element and the output element and the bending of the spring plate. In a second operating phase, variations in the transmitted torque are accompanied by the joint rotation of the input element and the output element.

Description

DAMPER, IN PARTICULAR FOR AN AUTOMOBILE CLUTCH Technical field of the invention

The invention relates to a shock absorber, in particular for an automobile clutch. State of the art

The documents FR 2 894 006, FR 2 913 256 and FR 2 922 620 illustrate torsion dampers fitted respectively to a double damping flywheel, a clutch friction and a lock-up clutch. The elastic damping means fitted to these torsion dampers are helical springs with a circumferential effect whose ends come, on the one hand, in abutment with stops integral with the input elements and, on the other hand, in support against stops integral with the output elements. Thus, any rotation of one of said elements relative to the other causes a compression of the springs of the damper in one direction or the other and said compression exerts a restoring force able to return said elements to a relative angular position. rest. The coil springs can be straight or bent.

Also known is FR 3 000 155 which discloses a torsion damper provided with resilient blades.

The invention aims to improve the torsion dampers above. Object of the invention

The invention thus relates to a shock absorber, in particular for an automobile clutch, comprising:

- an input element,

- An output member rotatable relative to the input member about an axis of rotation; damping means interposed between the input and output elements; the damping means comprising an elastic blade mounted on one of the input and output elements and interposed between the input and output elements so as to bend and transmit a torque of the input element to the input element; output element or vice versa,

in a first phase of operation, variations in the transmitted torque being accompanied by a relative rotation between the input element and the output element and the flexion of the elastic blade,

in a second phase of operation, the variations in the transmitted torque being accompanied by a rotation integral with the input element and the output element.

Thanks to the invention, it is possible to transmit a torque between the input and output elements, even in the event of destruction of the damping means. The invention also makes it possible to protect the damping means in the event of transmission of an over-torque resulting from limiting conditions of use or from a malfunction of the power unit.

Advantageously, the bending of the elastic blade during transmission of the torque is accompanied by an angular displacement between the input element and the output element in a first phase of operation, and the damper is arranged so as to in a second phase of operation, the torque is transmitted completely without damping.

If desired, the damper is arranged so that the first phase ends and the second phase begins when the torque transmitted between the input element and the output element exceeds a predetermined torque threshold, which torque threshold being greater than 20 Nm, especially greater than 50 Nm, for example greater than 100 Nm, especially greater than 300 Nm Preferably, the angular displacement between the input and output elements, in one or the other of the directions, is allowed up to a predetermined angle with respect to an angular position of rest, reached for a torque threshold. predetermined.

In one embodiment of the invention, the predetermined angle is greater than 30 °, in particular greater than 45 ° or 60 °, for example greater than 80 °.

Preferably, the total angular amplitude between the input element and the output element is greater than 60 °, in particular greater than 90 ° or 120 °, for example greater than 160 °.

Thus, the implementation of large relative deflections allows the use of damping means having a limited stiffness to improve efficiency.

Preferably, the elastic blade is arranged to deform, during operation, in a plane perpendicular to the axis of rotation. Preferably, the damper is a torsion damper.

In one embodiment of the invention, the resilient blade has a cam surface. Alternatively, one of the input and output elements is provided with a cam surface arranged to cooperate with said elastic blade.

Advantageously, the cam surface is located on the edge located radially outside the blade. Preferably, the resilient blade cooperates with a cam follower.

In one embodiment of the invention, the resilient blade is mounted on one of the input and output elements and the cam follower is a roller rotatably mounted on the other of the input and output elements. exit.

Preferably, the roller is rotatably mounted on the other of the input and output elements via a rolling bearing, ball or needle.

Advantageously, the cam follower is disposed radially outside the elastic blade.

In one embodiment of the invention, the damping means comprise a plurality of resilient blades.

Preferably, the damper comprises a second elastic blade provided with a cam surface and a second cam follower arranged to cooperate with the cam surface of said second elastic blade, the first and the second elastic blades being symmetrical with respect to the axis of rotation.

Preferably, the elastic blade comprises a fixing portion to one of said input and output elements. In one embodiment of the invention, the attachment portion of the resilient blades is an annular body carrying all the blades.

Preferably, the elastic blade has a total thickness greater than 3 mm, in particular greater than 5 or 10 mm, for example being about 12 mm or In one embodiment of the invention, the elastic blade is formed by a stack of lamellae.

Advantageously, the thickness of each lamella is less than 7 mm, being for example between 1 mm and 6 mm. Preferably, the elastic blade is metallic.

In one embodiment of the invention, the damper comprises end stops arranged so that the angular displacement between the input and output elements, in one direction and / or in the other direction. , is allowed up to the predetermined angle with respect to the angular position of rest.

Preferably, the end stops are carried by the input element and the output element. Preferably, the stops are located radially outside the areas of contact between the blade and the cam follower. Indeed, the more the stops are close to the axis of rotation, the greater the forces transmitted at the stops are important and the risk of destroying the stops is large. Thus, in a position located radially outside the contact areas between the blade and the cam follower, the distance separating the stops from the axis of rotation is large and the risk of destruction of the stops is reduced.

Preferably, at least one of the stops is bidirectional action. Preferably, the stops consist of projecting elements formed in the mass of the input and output elements. For example, the stops consist of projecting elements formed in the mass of the input and output elements cast iron. Preferably, the cam follower of the input member is mounted within a housing formed in the abutment of the input member.

Alternatively, the stops consist of inserts, for example by riveting on the input and output elements.

In one embodiment of the invention, each of the input and output elements comprises two stops arranged diametrically opposite. If necessary, one of the stops is a projecting element carried by the cam follower, for example by the end of the rivets or the cam follower fixing rods.

Preferably, one of the abutments is formed inside a cavity formed in the input or output element.

The invention also relates to a clutch friction disk comprising a damper according to the invention as described above. The invention also relates to a double damping flywheel comprising a damper according to the invention as described above.

If necessary, the damper is a double damping flywheel and the input and output elements are respectively primary and secondary flywheels.

The invention also relates to a damper for a motor vehicle comprising:

- An input member, intended to be fixed at the end of a crankshaft, and an output member, movable in rotation relative to each other about an axis of rotation; damping means for transmitting torque and damping rotational acyclisms between the input and output elements, said damping means comprising friction members arranged to exert a friction-resistant torque between the input elements and output, at an angular displacement between said input and output elements;

said damper being remarkable in that the damping means comprise an elastic blade, integral in rotation with one of said input and output elements, and provided with a cam surface; and in that the damper has a cam follower, carried by the other of said input and output members, and arranged to cooperate with said cam surface;

said cam surface being arranged such that, for angular displacement between the input member and the output member with respect to an angular rest position, the cam follower exerts a bending force on the elastic blade producing a reaction force capable of biasing said input and output elements towards said angular position of rest.

Thus, the construction and assembly of such a damper is simple since it requires a limited number of components in comparison with a coil spring damper.

In addition, the damping means are less sensitive to the centrifugal force than the helical springs of the prior art so that the quality of the vibration damping is only slightly impacted by the centrifugal force.

In addition, the structure of such a damper provides significant relative deflections which allows the use of damping means having a limited stiffness to improve efficiency. Moreover, such a damper may have a characteristic curve representing the variations of the torque transmitted as a function of the angular deflection which has slope variations without point of inflection or discontinuity. So, the characteristic curve does not present a zone of abrupt change of stiffness which causes discontinuities and shocks affecting the quality of damping.

Finally, the cam surface being carried by the elastic blade, the manufacture of a damper according to the invention may be partly standardized. Indeed, only the geometry and characteristics of the elastic blade require adaptations when the characteristics of a damper must be adapted to the characteristics of the intended application.

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

- The cam follower is a roller rotatably mounted on the other of said input and output elements.

- The roller is rotatably mounted on the other of said input and output elements by means of a rolling bearing.

the damper comprises a second elastic blade provided with a cam surface and a second cam follower arranged to cooperate with the cam surface of said second elastic blade, the first and the second elastic blades being symmetrical relative to the X axis of rotation

the first and the second elastic blades are carried by an annular body.

the first and second resilient blades are secured to one of said input and output elements, each independently.

the cam follower is arranged radially outside the elastic blade.

the cam surface is formed at a free end of the elastic blade. the elastic blade comprises a circumferentially extending curved portion at the free end of which the cam surface is formed.

the elastic blade is carried by an annular body which is fixed on the input element, the cam follower being carried by a rod extending between the output member and a web, the output member and the web extending on either side of said annular body.

the input element comprises a radially inner hub supporting a centering bearing of the output element on the input element and an annular portion having screw holes for fixing said damper to the nose of the crankshaft; a motor, extending radially beyond the centering bearing of the output member, the annular support body of the resilient blade being provided with passage orifices of said damper fixing screws on the nose of the output member; crankshaft.

the elastic blade is carried by an annular body integral with the output element, the input element comprising a radially inner hub supporting a rolling bearing, of centering of the output element with respect to the element of input, the rolling bearing having an inner ring cooperating with the radially inner hub and an outer ring clamped between the annular support body of the resilient blade and the output member.

- The friction members comprise a first friction washer adapted to be rotated by one of the input and output elements and a second friction washer adapted to be rotated by the other of the input elements and output, and a spring washer "Belleville" arranged to exert a thrust force of the first friction ring against the second friction ring.

- The damper comprises end stops capable of limiting the relative angular movement between the input and output elements.

the shock absorber is a double damping flywheel and the input and output elements are respectively the flywheels of primary and secondary inertia.

The invention will be better understood, and other objects, details, characteristics and advantages thereof will appear more clearly in the course of the following description of several particular embodiments of the invention, given solely for illustrative and non-limiting purposes. with reference to the appended figures. In these figures:

Figure 1 is a perspective view of a primary flywheel of the double flywheel according to a first embodiment.

Figure 2 is a perspective view of a secondary flywheel of the double damping flywheel according to the first embodiment.

Figure 3 is a front view of a double damping flywheel in which a portion of the secondary flywheel is not shown so as to display the damping means and the end stops. This is a second embodiment for which the angular aperture of the stops of the secondary flywheel is lower.

Figure 4 is a sectional view of the double damping flywheel of Figure 5 according to VI-VI.

FIG. 5 illustrates the double damping flywheel of FIG. 3, in end-of-travel stop position, during an angular displacement of the secondary flywheel with respect to the primary flywheel, in the counter-clockwise direction.

FIG. 6 illustrates the double damping flywheel of FIG. 5, in end-of-travel stop position, during an angular displacement of the secondary flywheel with respect to the primary flywheel, in the clockwise direction.

FIG. 7 is an example of a characteristic curve of a double damping flywheel, representing the torque transmitted as a function of the angular deflection in the first operating phase PI and in the second operating phase P2.

Figure 8 is a perspective view of a primary flywheel of the double damping flywheel according to a third embodiment.

FIG. 9 is a perspective view of a secondary flywheel of the double damping flywheel according to the third embodiment 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 double damping flywheel. By convention, the "radial" orientation is directed orthogonally to the X axis of rotation of the double damping flywheel determining the "axial" orientation and, from the inside towards the outside away from said axis X, the "circumferential" orientation is directed orthogonally to the X axis of rotation of the double damping flywheel and orthogonal to the radial direction. The terms "external" and "internal" are used to define the relative position of one element relative to another, with reference to the axis X of rotation of the double damping flywheel, an element close to the axis is thus qualified. internally as opposed to an outer member located radially peripherally.

We first refer to Figures 1 to 2 which illustrate a damper type double damping flywheel. Here the input element is a primary flywheel and the output element is a secondary flywheel.

Figures 1 to 2 show a double damping flywheel 1 according to a first embodiment. The double damping flywheel 1 comprises a primary flywheel 2, intended to be fixed at the end of a crankshaft of an internal combustion engine, not shown, and a secondary flywheel 3 which can be centered and guided on the primary flywheel 2 by means of a rolling bearing with ball bearings 4. The secondary flywheel 3 is intended to form the reaction plate of a clutch, not shown, connected to the input shaft of a gearbox . The flywheels of primary inertia 2 and secondary 3 are intended to be mounted movable about an axis of rotation X and are furthermore movable in rotation relative to each other about said axis X.

In this embodiment, it is seen that two cam followers are mounted on the primary flywheel and two resilient blades are mounted on the secondary flywheel. The primary flywheel 2 comprises a radially inner hub 5, supporting a centering bearing 4 of the secondary flywheel 3, which is provided with orifices 27 for the passage of screws, for fixing the double damping flywheel to the nose of the crankshaft.

An annular portion 6 of the primary flywheel extends radially and a cylindrical portion 7 of the primary flywheel extends axially, on the side opposite the motor, from the outer periphery of the annular portion. The primary flywheel 2 carries, on its outer periphery, a ring gear 10 for driving in rotation of the primary flywheel 2, using a starter.

The secondary flywheel 3 has a flat annular surface 13, turned on the opposite side to the primary flywheel 2, forming a bearing surface for a friction lining of a clutch disk, not shown.

The damping means comprise two resilient blades 17a, 17b which are here mounted integral in rotation with the secondary flywheel 3 and which carry cam surfaces 20, arranged to cooperate with the cam followers 21 carried by the primary flywheel 2. The blades resilient 17a, 17b are carried by an annular body 18. Said annular body 18 is fixed on the secondary flywheel 3 by means of a plurality of rivets 28 cooperating with orifices formed in the annular body 18 and in the secondary flywheel 3 .

The cam followers here are rollers 21, rotatably mounted on the primary flywheel 2, about an axis parallel to the axis of rotation X. The rollers 21 are movably mounted on cylindrical rods 22, fixed on the primary flywheel 2, via rolling bearings. The rollers 21 are held in abutment against their respective cam surface 20 and are arranged to roll against said cam surface 20 during a relative movement between the primary flywheels 2 and secondary 3. The rollers 21 are arranged radially outwardly of their cam surface 20 respective so as to maintain radially resilient blades 17a, 17b when subjected to centrifugal force. In order to reduce the parasitic friction likely to affect the damping function, the rollers 21 are advantageously mounted in rotation on the cylindrical rods by means of a rolling bearing. For example, the rolling bearing may be a ball bearing or roller. Advantageously, the rollers 21 have an anti-friction coating.

The cam surface 20 is arranged such that, for an angular displacement between the primary flywheel 2 and the secondary flywheel 3, relative to a relative angular position of rest, the roller 21 moves on the cam surface 20 and, in doing so, exerts a bending force on the elastic blade 17a, 17b. By reaction, the elastic blade 17a, 17b exerts on the roller 21 a return force which tends to bring the primary flywheels 2 and secondary 3 to their relative angular position of rest. Thus, the resilient blades 17a, 17b are able to transmit a driving torque from the primary flywheel 2 to the secondary flywheel 3 and a resistant torque of the secondary flywheel 3 to the primary flywheel 2.

The torsional vibrations and the irregularities of torque that are produced by the internal combustion engine are transmitted by the crankshaft to the primary flywheel 2 and generate relative rotations between the primary flywheel 2 and secondary 3. These vibrations and irregularities are damped. by bending the elastic blade 17a, 17b.

The double damping flywheel 1 of FIGS. 3 to 6 comprises end stops 36, 37 capable of limiting the relative angular displacement between the primary flywheel 2 and the secondary flywheel 3. The double damping flywheel comprises two pairs of limit stops 36 37 arranged in such a way that the angular displacement between the primary flywheel and the secondary flywheel, in both directions, is authorized to a predetermined angle. The primary and secondary flywheels here each comprise a pair of stops.

Such stops make it possible to transmit a torque between the primary flywheel 2 and the secondary flywheel 3, in the event of destruction of the damping means, or make it possible to protect the damping means in the event of transmission of over-torque resulting from limited operating conditions or powertrain malfunction. On the flywheels of primary and secondary inertia, the two stops are arranged diametrically opposite. The stops are formed in the mass of the primary flywheel and the secondary flywheel. The cam follower 21 of the input member is mounted within a housing formed in the abutment 36 of the input member. Figures 3 to 6 show a second embodiment of a double damping flywheel. The stops formed in the mass of the secondary flywheel are here arranged so that the angular displacement between the primary flywheel and the secondary flywheel is greater than in the previous embodiment. The angular aperture of the stops 37 is therefore smaller here. As illustrated in FIG. 4, the damping means of the double damping flywheel also comprise friction members arranged to exert a resistant torque between the primary flywheel 2 and the secondary flywheel 3 during their relative deflection. The friction members 32 comprise an elastic washer, of "Belleville type", a first friction washer, integral in rotation with the primary flywheel 2 and a second friction washer adapted to be rotated relative to the primary flywheel 2 when a relative movement between the primary and secondary 2 flywheels. The hub 5 of the primary flywheel 2 has a shoulder 29 serving to support the inner ring of the rolling bearing 4 and retaining said inner ring towards the motor. Furthermore, the outer ring of the rolling bearing 4 is clamped between the annular body 18, for supporting the elastic blades 17a, 17b, and the secondary flywheel 3. To do this, the annular body 18 has, on its inner periphery, a Shoulder 30 retaining the outer ring towards the engine and the secondary flywheel 3 has, on its inner periphery, a shoulder 31 retaining the outer ring, in the opposite direction to the motor.

Each of the primary and secondary flywheels has two stops 36, 37 arranged diametrically opposite. Such stops 36, 37 are therefore bidirectional action. During a relative rotation of the primary flywheel 2 in a first direction of rotation relative to the secondary flywheel 3, a first bearing surface of the stops 36 carried by the primary flywheel 2 abuts against a first bearing surface of the stops 37 carried by the secondary flywheel 3, as shown in Figure 5. In contrast, during a relative rotation of the primary flywheel 2 in the opposite direction relative to the flywheel secondary 3, a second bearing surface of the stops 36 carried by the primary flywheel 2 abuts against a second bearing surface stops 37 carried by the secondary flywheel 3, as shown in Figure 6. In the mode embodiment shown in FIGS. 3 to 6, the stops 36,

37 consist of protruding elements formed in the mass of primary flywheels 2 and secondary 3. Alternatively, the stops 36, 37 may consist of inserts, for example by riveting on the flywheels of inertia primary 2 and secondary 3. In the example described in Figures 3, 5 and 6, the total angular amplitude A between the primary flywheel and the secondary flywheel is about 105 °. As can be seen, the stops 36 37 are located radially outside the contact zones 50 between the roller 21 and the blade 17a 17b. Thus, because of the distance from the axis of rotation, the risk of destruction of the stops is reduced.

Figure 7 illustrates a characteristic curve of a double damping flywheel 1 made in accordance with the teachings of the invention. This characteristic curve represents the transmitted torque, expressed in Nm, as a function of the angular deflection, expressed in degrees. It should be noted that such a double damping flywheel 1 makes it possible in particular to obtain damping characteristic curves whose slope varies progressively, without discontinuity in the first phase of operation P1. Acyclisms and other variations of torque of the primary flywheel thus cause an angular deflection D between the primary flywheel 2 and the secondary flywheel 3 in a first phase of operation Pl. There is then a relative rotation between the primary flywheel and the secondary flywheel accompanied by a bending of the blade

On the other hand, in the second phase of operation, the slope is vertical because the increase in the transmitted torque is no longer accompanied by an angular clearance D between the primary flywheel 2 and the secondary flywheel 3. variations in torque on the primary flywheel do not cause additional angular deflection between the primary flywheel 2 and the secondary flywheel 3 in a second operating phase P2, the variations in the transmitted torque being accompanied by rotation of the primary flywheel and the secondary flywheel.

In this example, as seen in FIG. 7, the bending of the elastic blade 17a 17b during transmission of the torque is accompanied by an angular clearance D between the primary flywheel 2 and the secondary flywheel. 3 in the first phase of operation PI, to a predetermined angle (a) of about 52 ° in the forward direction (rotation of the primary flywheel by secondary ratio in the direction of rotation of the motor) and up to a predetermined angle (a ') of approximately 53 ° in the retro direction (rotation of the secondary flywheel relative to the primary flywheel in the opposite direction of engine rotation) . When the primary flywheel 2 and the secondary flywheel 3 are in abutment against each other and the transmitted torque increases, the damper enters the second operating phase (P2) for which the torque rotation is transmitted totally without damping, that is to say without increasing the angular clearance D between the primary flywheel 2 and the secondary flywheel 3.

In this example, the double damping flywheel is arranged so that the first phase ends and the second phase begins when the torque transmitted between the input element and the output element exceeds the thresholds C of 500 Nm, in the forward direction, and C of 450 Nm in the retro direction.

Figures 8 and 9 illustrate a double damping flywheel 1 according to a third embodiment. In this embodiment, the abutment 36 carried by the primary flywheel is formed on the end of the rivets or fixing rods 22 of the cam follower 21. This protruding element is intended to abut against a surface of stop 37 formed inside a cavity 60 of the secondary flywheel 3.

Although the invention has been described in connection with several particular embodiments, it is obvious that it is not limited thereto and that it comprises all the technical equivalents of the means described and their combinations if they are within the scope of the invention.

The use of the verb "to include", "to understand" or "to include" and its conjugated forms does not exclude the presence of other elements or steps other than those set out in a claim. The use of the indefinite article "a" or "A" for an element or a step does not exclude, unless otherwise stated, the presence of a plurality of such elements or steps.

In the claims, any reference sign in parentheses could be construed as a limitation of the claim.

Claims

Shock absorber, in particular for an automobile clutch, comprising:

- an input element,

an output member movable in rotation with respect to the input element about an axis of rotation (X);

damping means interposed between the input and output elements; the damping means comprising an elastic blade (17a; 17b; 17c; 17d) mounted on one of the input and output elements; and interposed between the input and output elements to flex and transmit torque from the input element to the output element or vice versa,

in a first operating phase (PI) variations in the transmitted torque being accompanied by a relative rotation between the input element and the output element and the flexion of the elastic blade,

in a second operating phase (P2), the variations in the transmitted torque being accompanied by a rotation integral with the input element and the output element.

2. Damper according to the preceding claim, characterized in that the damping means interposed between the input and output elements comprise an elastic blade (17a, 17b) mounted on one of the input and output elements; and interposed between the input and output elements to flex and transmit a torque between the input element and the output element, the variations of the transmitted torque causing an angular displacement (D) between the input element and the output element. input and the output element in a first operating phase (PI), and the damper being arranged so that, in a second operating phase (P2), the variations of the transmitted torque cause no angular deflection (D) between the input element (2) and the output element (3).

Shock absorber according to one of the preceding claims, characterized in that the damper is arranged in such a way that the first phase ends and the second phase begins when the torque transmitted between the input element and the element the output exceeds a predetermined torque threshold (C; C), this torque threshold being greater than 20 Nm, in particular greater than 50 Nm, for example greater than 100 Nm, in particular greater than 300 Nm

4. Damper according to claim 3, characterized in that the angular displacement (D) between the input and output elements, in one or the other of the directions, is allowed up to a predetermined angle (a; a ') reached for the predetermined torque threshold (C; C).

5. Shock absorber according to claim 4, characterized in that the predetermined angle (a; a ') is greater than 30 °, in particular greater than 45 ° or 60 °, for example greater than 80 °.

Shock absorber according to one of the preceding claims, characterized in that the elastic blade is mounted on one of the input and output elements and has a cam surface (20) located on the ridge located radially at an angle of outside the blade, and the resilient blade cooperates with a cam follower (21), for example a roller, rotatably mounted on the other of the input and output elements.

Shock absorber according to one of the preceding claims, characterized in that the elastic blade is metallic.

8. Shock absorber according to one of claims 4 to 7, characterized in that it comprises end stops (36; 37) arranged so that the angular movement between the input and output elements, in one direction and / or in the other direction, is allowed up to the predetermined angle (a, a ').

9. Damper according to claim 8, characterized in that the stops are located radially outside the contact areas (50) between the blade (17a; 17b) and the cam follower.

10. Shock absorber, according to one of claims 8 to 9, characterized in that at least one of the stops (36, 37) is bi-directional action.

11. Shock absorber according to one of claims 8 to 10, characterized in that the stops (36; 37) consist of projecting elements formed in the mass of the input and output elements.

Damper according to one of Claims 8 to 11 in combination with Claim 6, characterized in that the cam follower (21) of the input element is mounted inside a housing provided in the housing. stop (36) of the input element.

Shock absorber according to one of Claims 8 to 10 in combination with Claim 6, characterized in that one of the stops is a projecting element carried by the cam follower, for example by the end of the rivets or fastening rods (22) of the cam follower.

Shock absorber according to one of Claims 8 to 10 or 12 to 13, characterized in that one of the stops is arranged inside a cavity (60) formed in the input element or exit.

15. Clutch friction disc comprising a torsion damper according to one of the preceding claims.

16. Double damping flywheel comprising a damper according to one of the preceding claims.