FR3027986A1 - TORSIONAL SHOCK ABSORBER WITH BLADE DAMPING MEANS - Google Patents

Abstract

The invention relates to a torsion damper comprising: - a first element (2) and a second element (3) movable in rotation relative to each other about an axis of rotation X; and - damping means comprising an elastic blade (17a, 17b) integral with the second element (3) and a support element (21) carried by the first element (2) for transmitting a torque and damping the rotation acyclisms between the first element (2) and the second element (3); the damper comprising a limit device able to oppose the angular displacement between the first element and the second element in a relative direction of rotation, the end-of-stroke device comprising a resilient member (31) arranged to be biased when the angular displacement is greater than a predetermined threshold and to produce a restoring force acting against said angular deflection greater than said threshold.

Description

TECHNICAL FIELD OF THE INVENTION The invention relates to a torsion damper intended to equip a torque transmission device. The invention relates more particularly to the field of transmissions for a motor vehicle. STATE OF THE ART In the field of automobile transmissions, it is known to provide torque transmission devices with torsion dampers for absorbing and damping the vibrations and acyclisms generated by an internal combustion engine. The torsion dampers comprise an input member and an output member rotatable about a common axis of rotation and resilient damping means for transmitting the torque and damping rotational acyclisms between the input member. and the output element. Such torsion dampers are used in particular dual damping flywheels (DVA), clutch friction, in the case of a manual or robotic transmission, or locking clutches, also called "lock-up" clutches, equipping the hydraulic coupling devices, in the case of an automatic transmission. FR3000155 illustrates a torsion damper comprising two resilient damping means each formed by a resilient blade mounted on the input member and cooperating with a cam follower mounted on the output member. The blade and the cam follower of each elastic damping means 25 are arranged such that, for angular displacement between the input member and the output member, on either side of a position relative angular rest, the cam follower moves along the blade and, in doing so, exerts a bending force on the elastic blade. By reaction, the resilient blade exerts a restoring force on the cam follower which tends to return the input and output members to their angular rest position. The bending of the resilient blade thus makes it possible to damp the vibrations and irregularities of rotation between the input element and the output element while ensuring the transmission of torque.

However, in the presence of high torque, the cam followers may move circumferentially beyond the cam surfaces, or even beyond the free blade end with which they cooperate. Such displacements of the cam followers with respect to the corresponding blades make any subsequent cooperation between said cam followers and said blades impossible. Such torsion dampers therefore do not provide a completely satisfactory solution. OBJECT OF THE INVENTION The object of the invention is to remedy this problem by proposing a torsion damper in which the cam follower is held in constant cooperation with the cam surface without substantially reducing the performance of the torsion damper, in particular. particularly without generating significant noise. For this purpose, and according to a first aspect, the invention relates to a torsion damper for a torque transmission device comprising: a first element and a second element movable in rotation relative to each other around a rotation axis X; and damping means for transmitting a torque and damping the rotational acyclisms between the first member and the second member, the damping means having a resilient blade integral with the second member and a bearing member carried by the first member; element and arranged to cooperate with said elastic blade, said elastic blade being arranged such that, for an angular displacement between the first element and the second element relative to an angular position of rest, the support element exerts a force bending on the resilient blade producing a reaction force adapted to bias said first and second members toward said angular rest position; in which the torsion damper comprises a limit device able to oppose the angular displacement between the first element and the second element in a relative direction of rotation, the end-of-travel device comprising at least one elastic member. arranged to be biased when the angular displacement between the first element and the second element in said relative direction of rotation is greater than a predetermined threshold, the elastic member being arranged to produce a restoring force acting against a deflection angular in said relative direction of rotation greater than said threshold. Thus, the elastic member progressively slows down the end of rotation stroke between the first and second elements.

Thus, the end-of-travel device limits or even prevents the impact between abutment surfaces so that the noise nuisance associated with such an impact is low or non-existent. According to other advantageous embodiments, such a damper may have one or more of the following features: the elastic member is arranged to produce the restoring force acting against the angular deflection with a circumferential clearance, the elastic member is circumferentially compressible, the elastic member being held circumferentially between a first bearing surface and a second bearing surface integral in rotation with one of the first element and the second element, the end-of-stroke device further comprising a circumferential vis-à-vis compression surface of the resilient member and secured in rotation to the other of the first member and the second member so as to compress the resilient member against one of the bearing surfaces when an angular displacement between the first element and the second element above said threshold. the end-of-travel device further comprises a stop capable of limiting the angular displacement between the first element and the second element at a maximum angular displacement, said maximum angular displacement between the first element and the second element being greater than said threshold from which the elastic member is biased. the torsion damper further comprises a guide washer mounted on the first element by fixing means, the first bearing surface being jointly formed by a first projection projecting axially from the first element and by the guide washer, the second bearing surface being jointly formed by a second boss projecting axially from the first member and by the guide washer, the first boss and the guide washer being separated axially by a gap, the compression surface being able to engage in said space during relative rotation between the first member and the second member. the support element cooperating with the elastic blade is carried jointly by the first element and the guide washer. the torsion damper further comprises a web mounted to rotate with the second member, the web having a tab projecting radially outwardly, the tab carrying the compression surface. the bumper has a first abutment surface formed by the first boss and a second abutment surface formed by a finger projecting from the tab. the torsion damper further comprises a friction member between the first element and the second element, the friction member comprising a first friction washer integral in rotation with the first element and a support washer adapted to exert a force according to an axial direction on the first friction ring towards the web so as to press the first friction washer against the web.

The first friction washer presses against the veil via a second friction washer. the end-of-stroke device comprises two elastic members acting against the relative rotation between the first element and the second element with a circumferential clearance in a first direction of relative rotation and two elastic members acting against the rotation relative between the first element and the second element with a circumferential clearance in a second relative direction of rotation opposite the first direction of relative rotation. the second boss protrudes axially from the first element and forms the second bearing surface of two separate elastic members intended to act against the relative rotation between the first element and the second element in opposite directions of rotation. the torsion damper further comprises: - a guide washer mounted on the second element, the first and second bearing surfaces being formed by the guide washer, - a web integral in rotation with the first element and comprising a tab, said tab forming the compression surface. the bumper comprises a first abutment surface carried by the tab of the web and a second abutment surface carried by the guide washer. the torsion damper further comprises a friction member between the first and the second element, the friction member comprising a first friction washer integral in rotation with the first element and a support washer adapted to exert a force according to a axial direction on the first friction washer in the direction of the guide washer so as to press the first friction washer against the guide ring. The first friction washer bears against the guide washer via a second friction washer, the web comprises the compression surface of the elastic member and one of the stop surfaces of the bumper the leg of the web comprises a first compression surface capable of compressing a resilient member in a first direction of relative rotation and a second compression surface adapted to compress another elastic member in the other direction of relative rotation. the two elastic members acting in the same direction of relative rotation are arranged diametrically opposite. the elastic members are springs, for example helical springs. the stiffness of the elastic member is greater than the stiffness of the elastic blade when the angular displacement is greater than the threshold in one embodiment, the abutment abutment surface is formed on the compression surface of the web. according to another embodiment, the stop surface of the stopper carried by the guide washer is located circumferentially between the two bearing surfaces which hold the elastic member.

According to a second aspect, the invention relates to a torque transmission element, in particular for a motor vehicle, comprising a torsion damper according to the first aspect of the invention. In one embodiment, the torque transmission member 30 has two torsion dampers arranged in series. Such an arrangement makes it possible to further increase the angular deflection. In another embodiment, the torque transmission member has two torsion dampers arranged in parallel. Thus, the torque transmission member may have a higher torque capacity.

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: FIG. 1 is an exploded schematic perspective view of a double damping flywheel, according to a first embodiment of the invention. FIG. 2 is a sectional view of the double damping flywheel of FIG. mounted state.

Figure 3 is a front view of the double damping flywheel of Figure 1 in which the secondary flywheel is not shown, so as to display the damping means. Figure 4 is a perspective view of the double damping flywheel of Figure 1 in which the secondary flywheel is not shown so as to display the damping means. FIG. 5 is a front view of the double damping flywheel of FIGS. 1 to 4 in maximum angular deflection position, in which the secondary flywheel and the damping means are not shown so as to display the end device race.

FIG. 6 is a schematic perspective view of the double damping flywheel of FIG. 5 in which the secondary flywheel and the damping means are not shown so as to visualize the end-of-travel device. FIG. 7 is a detailed view of the friction means of the double flywheel of FIG. 1. FIG. 8 is a diagrammatic view of damping means with an elastic blade, illustrating the deflection of the blade during an angular deflection between flywheels, primary and secondary, in a direct sense.

Figure 9 is a schematic view of elastic blade damping means, illustrating the deflection of the blade during an angular movement between the flywheels, primary and secondary, in a retro sense.

Figure 10 is a schematic perspective view of a dual damping flywheel in the rest position according to another embodiment of the invention wherein the secondary flywheel is not shown. Figure 11 is a partial sectional view of the double damping flywheel of Figure 10 in the presence of an angular movement between the primary flywheel and the secondary flywheel. Figure 12 is a schematic perspective view of a guide ring and a web of the dual flywheel of Figure 10 in the rest position.

Figure 13 is a schematic perspective view of a detail of a guide ring and a web of the dual flywheel of Figure 10 in the presence of an angular movement between the primary flywheel and the secondary flywheel. 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 X axis of rotation of the elements of the torsion damper 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 X axis of rotation of the torsion damper, an element close to the axis is thus described as internal as opposed to an external element located radially at the periphery. The torsion damper illustrated in Figures 1 to 7 and 10 to 13 is a dual flywheel for a drive chain of a motor vehicle. However, the torsion damper according to the invention could, for example, be integrated with a lock-up clutch of a hydraulic coupling device or with a clutch friction disc. Note further that, in the case of a clutch friction disk, the torsion damper according to the invention can form a main damper and / or a pre-damper.

Figures 1 and 2 respectively show an exploded perspective schematic view of a double damping flywheel and a sectional view of said double flywheel. The double damping flywheel 1 comprises a primary flywheel 2, 5 intended to be fixed at the end of a crankshaft of an internal combustion engine, not shown, and a secondary flywheel 3 which is centered and guided on the primary flywheel 2 by means of a bearing 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 movably about an axis of rotation X and are furthermore movable in rotation relative to each other about said axis X. The steering wheel 2 comprises a radially inner hub 5 supporting the bearing 4, an annular portion 6 extending radially and a cylindrical portion 7 extending axially, on the opposite side to the motor, from the outer periphery of the annular portion 6. The portion annular 6 is provided, on the one hand, with holes 8 for the passage of fastening screws (not shown) intended for fastening the primary flywheel 2 to the crankshaft of the engine and, on the other hand, orifices for the passage of rivets 9 for fixing the damping means on the secondary flywheel 3. The primary flywheel 2 carries, on its outer periphery, a ring gear 10 for 20 driving in rotation of the primary flywheel 2, using a starter. The hub 5, radially internal, of the primary flywheel has a shoulder 11. A washer (not shown) can be installed on the shoulder 11 to support the clutch forces. The bearing 4 is mounted tightly on the hub 5. Similarly, the secondary flywheel 3 has on its inner periphery a shoulder 12 serving to support the bearing. 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 secondary flywheel 3 has, close to its outer edge, pads 14 and orifices 15 for mounting a clutch cover (not shown). The secondary flywheel 3 further comprises orifices 16, arranged vis-à-vis the orifices 8 formed in the primary flywheel 2, and for the passage of the mounting screws of the double damping flywheel 1 on the crankshaft.

The primary flywheels 2 and secondary 3 are coupled in rotation by damping means. These damping means comprise two resilient blades 17a, 17b mounted integral in rotation with the secondary flywheel 3. To do this, the resilient blades 17a, 17b are carried by an annular body 18 provided with orifices for the passage of fastening rivets 9 The two elastic blades 17a, 17b are symmetrical with respect to the axis of rotation X of the clutch disk. The annular body 18 is fixed on the secondary flywheel 3 by means of the rivets 9. The elastic blades 17a, 17b have a cam surface 20 which is arranged to cooperate with a cam follower, carried by the primary flywheel 2. The resilient blades 17a, 17b have a curved portion extending substantially circumferentially. The radius of curvature of the curved portion and the length of this curved portion are determined according to the desired stiffness of the elastic blade 17a, 17b. The elastic blade 17a, 17b may, as desired, be made in one piece or be composed of a plurality of lamellae arranged axially against each other. The cam followers are rollers 21 carried by cylindrical rods 22 fixed on the one hand to the primary flywheel 2 and on the other hand to a guide washer 23. The rollers 21 are rotatably mounted on the cylindrical rods 22 around the cylinder. an axis of rotation parallel to the axis of rotation X. 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 radially outwardly from their respective cam surfaces 20 so as to radially maintain the 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. In one embodiment, 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 (forward direction) and a resistant torque of the secondary flywheel 3 to the primary flywheel 2 (retro direction). The operating principle of elastic blade damping means 17a, 17b is detailed by way of indicative example in relation to FIGS. 8 and 9.

When a driving motor torque is transmitted from the primary flywheel 2 to the secondary flywheel 3 (forward direction), the torque to be transmitted causes a relative movement between the primary flywheel 2 and the secondary flywheel 3 in a first direction (see Figure 8). The roller 21 is then moved by an angle with respect to the elastic blade 17a. The displacement of the roller 21 on the cam surface 20 causes a flexion of the elastic blade 17a along an arrow A. To illustrate the bending of the elastic blade 17a, the elastic blade 17a is shown in solid lines in its angular position of rest and in dotted lines during an angular deflection. The bending force P depends in particular on the geometry of the elastic blade 17a and its material, in particular its transverse modulus of elasticity. The bending force P is decomposed into a radial component Pr and a tangential component Pt. The tangential component Pt allows the transmission of the engine torque. In response, the elastic blade 17a exerts on the roller 21 a reaction force whose tangential component constitutes a restoring force which tends to bring the primary flywheels 2 and secondary 3 to their relative angular position of rest. When a resisting torque is transmitted from the secondary flywheel 3 to the primary flywheel 2 (retro direction), the torque to be transmitted causes a relative movement between the primary flywheel 2 and the secondary flywheel 3 in a second opposite direction (see Figure 9). The roller 21 is then moved by an angle [3 with respect to the elastic blade 17a. In this case, the tangential component Pt of the bending force has a direction opposite to the tangential component of the bending force illustrated in FIG. 8. Similarly, the elastic blade 17a exerts a reaction force of opposite direction. to that illustrated in Figure 8, so as to bring the primary flywheels 2 and secondary 3 to their relative angular position of rest. 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 flexing the elastic blade 17a. Referring to Figure 7, which shows a detailed view of a dual flywheel of Figures 1 to 6, we see that the damping means comprise friction members arranged to exert a resistant torque between the primary flywheel 2 and the secondary flywheel 3 during their relative travel. The friction members are able to dissipate the energy accumulated in the elastic blades 17a, 17b. The friction members comprise a first friction washer 24, preferably plastic, secured in rotation with the primary flywheel 2 with a support washer 25 fixed to the primary flywheel 2. The support washer 25 has a general annular shape of revolution about the axis X. This support washer 25 is for example fixed on the primary flywheel 2 with the fixing means of the primary flywheel 2 on the crankshaft.

The support washer 25 is formed in a metal sheet. It comprises at least one orifice 26 formed by cutting a tongue. The edge of the orifice 26 forms a stop intended to cooperate with a complementary abutment formed on the first friction washer 24 so as to fasten them in rotation. The first friction washer 24 comprises at least one lug 27 bearing this complementary abutment and passing through the orifice 26. Preferably, the first friction washer 24 has a plurality of legs 27 distributed circumferentially, each lug 27 being housed in an orifice 26. corresponding. The friction members also comprise a second friction washer 28, preferably of plastic, integral in rotation with the secondary flywheel 3. More particularly, the second friction washer 28 is carried by a sail 19 integral in rotation with the secondary flywheel 3. The sail 19 is for example fixed on the secondary flywheel 3 with the fastening rivets 9 of the resilient blades 17a, 17b. An inner end 29 of the web 19 is located radially inside the fastening rivets 9 of the blades 17a, 17b. The second friction washer 28 has an annular shape with a "U" -shaped section, the concavity of which faces outwards and which is tightly mounted on the inner end 29 of the veil 19. A Belleville washer-type washer 30 , interposed between a stop carried by the support washer 25 and the first friction washer 24 provides a thrust force of the first friction washer 24 against the second friction washer 28. Figures 1 to 6 illustrate a double damping flywheel 1 further comprising end-of-travel devices capable of limiting the relative angular displacement between the primary flywheel 2 and the secondary flywheel 3. Such end-of-travel devices make it possible to protect the damping means in the event of transmission. over-torque resulting from limited operating conditions or powertrain malfunction. The double damping flywheel shown in FIGS. 1 to 6 comprises, for each relative direction of rotation, two diametrically opposed end-of-travel devices intended to limit the angular displacement between the primary flywheel 2 and the secondary flywheel 3. As illustrated in FIG. 1, each end-of-travel device comprises an elastic element 31 having a circumferential effect housed between a first and a second circumferential bearing surface of the primary flywheel 2. This elastic element 31 is able to cooperate with a compression surface 36 of the sail 19 so that, during a rotation between the primary flywheel 2 and the secondary flywheel 3 greater than a threshold, the compression surface 36 compresses the elastic element 31 against the second circumferential bearing surface. The elastic element 31 is for example in the form of a helical spring 31. The elastic element 31 is axially locked between the primary flywheel 2 and the guide washer 23. The elastic element 31 is circumferentially blocked between a first circumferential bearing surface and a second circumferential bearing surface. The first circumferential bearing surface is jointly formed by a first projection 32 projecting axially from the primary flywheel 2 and a first edge 33 formed by a window 34 formed in the guide washer 23. The second circumferential bearing surface is formed jointly by a second boss 99 protruding axially from the primary flywheel 2 and a second edge 98 formed by the window 34 of the guide washer 23, said second edge 98 being opposite the first edge 33 of the window 34. A space axial axis separates each first boss 32 of the guide washer 23. In the embodiment shown, each end-of-stroke device comprises two elastic elements 31. The second boss 99 advantageously forms the second abutment surface for two separate elastic members 31 intended to each to limit rotation between the primary flywheel 2 and the secondary flywheel 3 according to directions opposed. The web 19 has two tabs 37 diametrically opposed. Each tab 37 has two circumferentially opposite lateral ends. The two lateral ends of a tab 37 form the compression surfaces 36 of the end-of-stroke device in opposite directions of rotation. During an angular displacement between the primary flywheel 2 and the secondary flywheel 3 greater than a threshold, the corresponding lateral end of the tabs 37 are interposed between the first boss 32 and the guide washer 23 of the two end-of-stroke devices. to bring each compression surface 36 into contact with the corresponding elastic member 31. The increase in the angular displacement between the primary flywheel 2 and the secondary flywheel 3 after contacting the compression surfaces 36 and the elastic elements 31 causes the compression of the elastic elements 31 between the compression surfaces 36 and the second bearing surfaces. corresponding circumferential Each lug 37 also comprises a finger 38 protruding axially towards the primary flywheel 2. In the rest position of the double damping flywheel, the finger 38 of each lug 37 is vis-à-vis circumferential first bosses 32 intended to cooperate with the lateral ends of said tab 37. For each end-of-stroke device, the circumferential distance between the compression surface 36 and the elastic element 31 is less than the distance separating the finger 38 from the first projection 32. Thus, when a rotation between the primary flywheel 2 and the secondary flywheel 3, the contact between the compression surface 36 and the elastic element 31 takes place prior to a contact between the finger 38 and the first boss 32. The distance separating the finger 38 from the first boss 32 is chosen so that the contact between the finger 38 and the first boss 32 takes place from a compression threshold of the elastic element 31. This is that is to say that the finger 38 serves as a complementary stop to avoid too much compression of the elastic element 31. The compression of the elastic member 31 dampens and / or block the rotation between the primary flywheel 2 and the secondary flywheel 3 in a progressive manner so that no noise-generating shock occurs and the abutment of the finger 38 on the first boss 32 avoids the degradation of the elastic element, for example in case of -couple.

As illustrated in Figures 1 to 4, in the rest position, the tabs 37 of the web 19 are spaced from the elastic elements 31. Conversely, and as shown in Figures 5 and 6, in the maximum angular displacement position between the primary flywheel 2 and the secondary flywheel 3, the diametrically opposed elastic elements 31 are each compressed between the compression surface 36 of one of the tabs 37 of the web 19 and the second corresponding bearing surfaces. Furthermore, the finger 38 of said tabs 37 is then in abutment against the first bosses 32, thus limiting the angular displacement between the primary flywheel 2 and the secondary flywheel 3 and the compression of the elastic element 31. In the case not shown in FIG. a symmetrically angled blade, the distance 15 between the compression surfaces 36 of the elastic members 31 may be identical when the torsion damper is in the rest position. However, preferably, the direction of direct rotation is preferred in the retro sense. Thus, the distance between the compression surfaces 36 of the elastic members 31 for the end-of-travel devices in the retro direction is advantageously less than the distance between the compression surfaces 36 of the elastic members 31 of the end-of-stroke devices in the longitudinal direction. direction of direct rotation. Preferably, in the rest position of the double flywheel, the compression surfaces 36 intended to cooperate with the elastic elements 31 in the retro direction are separated by 20 ° and the compression surfaces 36 intended to cooperate with the elastic element 31 in the forward direction are separated by 50 °. Thus, the elastic elements 31 are compressed only after a certain angular displacement between the primary flywheel 2 and the secondary flywheel 3. Likewise, the distance separating the finger 38 from each leg 37 and the corresponding first boss 32 is smaller in the direction of retro rotation than in the direction of direct rotation. Thus, each finger 38 is for example separated from 30 ° of the first boss 32 in the retro direction and 60 ° of the first bosses 32 in the forward direction. In a second embodiment shown in FIGS. 10 to 13, the elements that are identical or that fulfill the same function are referenced with the same numbers increased by 100. In this second embodiment, the elastic elements 131 are integral in rotation with the secondary flywheel 103 and the compression surfaces 136 are integral in rotation with the primary flywheel 102. For this, the guide ring 123 is mounted to rotate with the secondary flywheel. The guide washer has two lugs 139 diametrically opposed and projecting radially outwardly. Each lug 139 has a pair of housings for axially and circumferentially locking a pair of elastic members 131, said housings each having the first and second circumferential bearing surface limiting the circumferential displacement of the corresponding elastic member 131, such as 10 and 12. Furthermore, as illustrated in FIG. 11, the housings in which the elastic elements 131 are housed have a lateral opening 140. In this second embodiment, the web 119 is mounted on the primary flywheel 102. The legs 137 of the sail 119 are circumferentially opposite the elastic elements 131 so as to, during an angular displacement between the primary flywheel 102 and the secondary flywheel greater than a threshold, insert in the lateral opening 140 of the corresponding housing to compress the elastic member 131 (see Figure 11). In this second embodiment, the finger 138 is carried by the guide washer 123 and limits the angular displacement between the primary flywheel 102 and the secondary flywheel beyond a compression threshold of the elastic element 131 by cooperating with a lateral surface 141 of the lugs 137 of the web 119. For this, the finger 138 protrudes axially from the guide washer 123 towards the primary flywheel 102 and is circumferentially opposite the lateral faces 141 of the lugs 137. Moreover, this second embodiment differs from the embodiment shown in FIG. 7 in that the second friction washer 128 is carried by a guide washer 123 integral in rotation with the secondary flywheel 103. 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 as well as their combinations if they fall within the scope of the invention.

For example, in an embodiment not shown, a single elastic element can cooperate with two separate tabs of the web. Such an elastic element is housed between two first bosses, each first boss fulfilling the role of first bearing surface or second bearing surface in function of the relative direction of rotation between the primary flywheel and the secondary flywheel. Similarly, the web may comprise a tab for each end-of-stroke device, each tab comprising a single compression surface and a single finger intended to cooperate with a single elastic element.

The use of the verb "to include", "to understand" or "to include" and of its conjugated forms does not exclude the presence of other elements or stages other than those set out in a claim. The use of the indefinite article "a" or "an" 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 can not be interpreted as a limitation of the claim.

Claims (13)

REVENDICATIONS1. A torsion damper for a torque transmission device comprising: a first member (2) and a second member (3) rotatable relative to each other about an axis of rotation X; and damping means for transmitting a torque and damping the rotation acyclisms between the first element (2) and the second element (3), the damping means comprising an elastic blade (17a, 17b) mounted integral with the second element (3) and a support element (21) carried by the first element (2) and arranged to cooperate with said elastic blade (17a, 17b), said elastic blade (17a, 17b) being arranged in such a way that, for an angular displacement between the first element (2) and the second element (3) relative to an angular position of rest, the support element (21) exerts a bending force on the elastic blade (17a, 17b) producing a reaction force able to return said first and second elements towards said angular position of rest; the torsion damper being characterized in that it comprises an end-of-stroke device able to oppose the angular displacement between the first element and the second element in a relative direction of rotation, the end-of-travel device comprising at least one less an elastic member (31) arranged to be biased when the angular displacement between the first element (2) and the second element (3) in the said relative direction of rotation is greater than a predetermined threshold, the elastic member (31) being arranged to produce a restoring force acting against an angular deflection in said relative direction of rotation greater than said threshold A torsion damper as claimed in claim 1, wherein the elastic member (31) is circumferentially compressible, the elastic member (31) being circumferentially held between a first bearing surface (32) and a second bearing surface integral in rotation with one of the first element (2) and the second element (3), the end-of-travel device further comprising a compression surface (36) circumferentially opposite the elastic member (31) and integral in rotation with the other of the first element (2) and the second element (3) so as to compress the elastic member (31) against one of the bearing surfaces during an angular deflection between the first element (2) and the second element (3) above said threshold. 3. Torsion damper according to claim 1 or 2, wherein the end-of-travel device further comprises a buffer capable of limiting the angular displacement between the first element and the second element at a maximum angular displacement, said maximum angular displacement between the first element (2) and the second element (3) being greater than said threshold from which the elastic member (31) is biased. 4. torsion damper according to one of claims 2 to 3, further comprising a guide ring (23) mounted on the first member (2) by fastening means (35), the first bearing surface being formed together by a first boss (32) protruding axially from the first member (2) and by the guide washer (23), the second bearing surface being jointly formed by a second boss (99) projecting axially from the first member ( 2) and by the guide washer (23), the first boss (32) and the guide washer (23) being separated axially by a space, the compression surface (36) being able to engage in said space during relative rotation between the first element (2) and the second element (3). Torsion damper according to Claim 4, in which the bearing element (21) cooperating with the elastic blade (17a, 17b) is carried jointly by the first element (2) and the guide washer (23). . 6. torsion damper according to one of claims 4 or 5, further comprising a web (19) rotatably mounted to the second member (3), the web (19) having a tab (37) projecting radially to the the outside, the lug (37) carrying the compression surface (36). A torsion damper according to claim 6 in combination with claim 3, wherein the bumper has a first abutment surface formed by the first boss (32) and a second abutment surface formed by a finger (38) projecting from the tab (37). 30 8. torsion damper according to one of claims 6 to 7, further comprising a friction assembly between the first element (2) and the second element (3), the friction assembly comprising a first friction washer (24); ) integral in rotation with the first element (2) and a bearing washer (30) able to exert a force in an axial direction on the first fogging washer (24) in the direction of the web (19) so as to support the first washer friction against the veil. Torsion damper according to one of claims 2 to 3, further comprising - a guide washer (123) mounted on the second element (103), the first and second bearing surfaces being formed by the guide washer. (123), - a web (119) integral in rotation with the first element (102) and comprising a tab (137), said tab forming the compression surface (136). Torsion damper according to claim 9 in combination with claim 3, wherein the bumper has a first abutment surface carried by the lug (137) of the web (119) and a second abutment surface carried by the guide washer. (123). 11. torsion damper according to one of claims 9 to 10, further comprising a friction assembly between the first and the second element, the friction assembly comprising a first friction washer integral in rotation with the first element (102). and a bearing washer adapted to exert a force in an axial direction on the first friction washer in the direction of the guide washer (123) so as to press the first friction washer against the guide washer (123). 12. torsion damper according to any one of claims 1 to 11, wherein the end-of-stroke device comprises two resilient members (31) acting against the relative rotation between the first element (2) and the second element (3) with a circumferential clearance in a first direction of relative rotation and two elastic members (31) acting against the relative rotation between the first element (2) and the second element (3) with a circumferential clearance according to a second direction of rotation opposite to the first direction of relative rotation. 13. Torque transmission element, in particular for a motor vehicle, comprising a torsion damper according to one of claims 1 to 12.