FR3038681A1 - TORQUE TRANSMISSION DEVICE EQUIPPED WITH DAMPING MEANS AND A TORQUE LIMITING DEVICE - Google Patents

Abstract

The invention relates to a torque transmission device for a vehicle transmission chain; said torque transmission device having - a first member (2) and a second member (3a) rotatable relative to each other about an axis of rotation X; and - an intermediate element (3b) disposed in a torque transmission path between the first element (2) and the second element (3a); - the intermediate element (3b) being coupled to said first element (2) by elastic damping means (28, 29) and being associated with said second element (3a) by a torque limiter (21); said torque transmission device being remarkable in that it comprises stop means capable of limiting the relative rotation of the first element (2) with respect to the intermediate element (3b) and able to intervene before the release of the limiter of couple.

Description

TECHNICAL FIELD The invention relates to the field of transmissions for a motor vehicle and relates more particularly to a torque transmission device equipped with damping means, such as a double damping flywheel.

Technological background

An explosion engine presents, because of explosions succeeding in the cylinders of the engine, acyclisms. In order to filter the vibrations generated by the acyclisms upstream of the gearbox, it is known to equip the vehicle transmissions with a torque transmission device comprising means for damping vibrations, such as a double steering wheel. damper (DVA). Otherwise, vibrations entering the gearbox would cause in operation shocks, noises or noise particularly undesirable.

It is also known to equip the torque transmission devices with a torque limiter capable of limiting the torque passing through the transmission chain of the motor vehicle so as to protect the equipment sensitive to overtires.

A double damping flywheel equipped with such a torque limiter is disclosed in the document FR2738606. The double damping flywheel comprises a primary flywheel intended to be fixed to the crankshaft of an engine, a secondary flywheel intended to constitute the reaction plate of a friction clutch and elastic damping means acting between the two wheels. The secondary flywheel is formed in two parts, namely a first central portion movable on the primary flywheel and on which the resilient damping means act and a second outer portion rotatably mounted on the first central portion and designed to constitute the reaction plate of the friction clutch. The torque limiter is interposed between the two aforementioned parts of the secondary flywheel and allows a relative rotation of the two parts relative to each other when the torque applied to one of the two parts is greater than or equal to a threshold of the torque limiter is triggered so that the overcouples are not transmitted through the transmission chain of the vehicle.

The torque limiter is constituted by friction coupling means which exert between the two parts of the secondary flywheel a friction-resistant torque which makes it possible to fasten them in rotation as long as the torque applied to one of the two parts is below the threshold triggering the torque limiter and allowing relative rotation when the applied torque is greater than or equal to said trip threshold. Such a friction torque limiter, however, does not guarantee a precise trigger. It is indeed difficult to limit the uncertainties as to the trigger threshold of the torque limiter, given the manufacturing tolerances of its elements. In addition, the trip threshold of the torque limiter is likely to undergo significant variations depending on the temperature variations of its components and their degree of wear, in particular. Therefore, because of the uncertainties as to the trigger threshold of the torque limiter, the elastic damping means are likely to be excessively stressed in case of over-torque. The torque limiter is therefore not able to provide effective protection of the elastic damping means. summary

An idea underlying the invention is to provide a torque transmission device combining damping means and a torque limiter to solve the disadvantages of the state of the art, allowing increased protection of the elastic means depreciation.

According to one embodiment, the invention provides a torque transmission device for a vehicle transmission chain; said torque transmission device comprising: - a first member and a second member movable in rotation relative to each other about an axis of rotation X; and an intermediate element disposed in a path for transmitting torque between the first element and the second element; the intermediate element being rotatable relative to the first element about the axis of rotation X and being elastically coupled to the said first element by resilient damping means so as to allow a torque transmission with damping of the vibrations; between the first element and the intermediate element; the intermediate element being movable in rotation relative to the second element about the axis of rotation X and being associated with said second element by a torque limiter, the torque limiter being arranged to join in rotation the intermediate element and the second element when a torque transmitted between the intermediate element and the second element has a value less than a trip threshold of the torque limiter and to allow relative rotation between the intermediate element and the second element when a torque applied to the intermediate element or the second element has a value greater than or equal to said tripping threshold so as to limit the torque transmitted between the intermediate element and the second element; said torque transmission device further comprises stop means capable of limiting the relative rotation of the first element relative to the intermediate element at least in a relative end-of-travel position, said relative end-of-travel position being intended for be reached for a torque transmitted between the first element and the intermediate element in a first direction taking a value greater than or equal to a stopping torque, said stop means being arranged in such a way that the stopping torque is less than trip threshold of the torque limiter.

Thus, thanks to the stop means, the torque limiter is triggered, at least in one direction of transmission of the torque, for a predetermined deflection angle between the first element and the intermediate element, which makes it possible to ensure effective protection elastic damping means.

In other words, by freezing the relative position of the first and second elements, and thereby the stresses on the elastic means, before the release of the torque limiter, the maximum loads likely to act on the elastic means are precisely demarcated.

In addition, the presence of the torque limiter protects all sensitive parts of the transmission chain (tabs tray, gearbox, ...).

Consequently, the combination of the torque limiter and the abovementioned abutments makes it possible, on the one hand, to protect the damping means by means of abutment means which precisely limit the maximum torque that can be transmitted by the elastic means and, d on the other hand, to avoid transmission by these abutment means, overtures and shocks to the rest of the transmission chain, thanks to the presence of the torque limiter.

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

The trip threshold of the torque limiter is likely to undergo variations between a minimum threshold and a maximum threshold, and the stop torque is below the minimum trip threshold of the torque limiter. Thus, the variations of the trip threshold of the torque limiter have no impact on the damping characteristic curve and the performance of the damper.

The stop means are carried by the first element and the intermediate element. -

Preferably, the stop means are arranged in parallel with the elastic damping means. In this case, by integrating a torque limiter whose minimum triggering threshold is greater than the stop torque, it is possible to ensure that the damping curve is respected over the entire range of angular deflection. the damper, regardless of the variations of the tripping threshold of the torque limiter and the stiffness of the damper, especially at the end of travel.

The device comprises at least two abutment surfaces carried by the first member and the intermediate member, these two abutment surfaces being arranged to come into contact with one another to limit the relative rotation between the first member and the second member. intermediate element.

The aforesaid first sense is a retro direction, that is to say a direction corresponding to a torque transmission of the wheels to the vehicle engine.

The stop means are able to limit the relative rotation of the first element relative to the intermediate element between two relative end positions; the two relative end-of-travel positions being intended to be respectively reached for a torque transmitted between the first element and the intermediate element in a first direction taking a value greater than or equal to a retro-stopping torque and for a torque transmitted between the first element and the intermediate element, in a second direction opposite to said first direction, taking a value greater than or equal to a direct stop torque; said stop means being arranged such that the direct stop torque and the reverse stop torque are lower than the trip threshold of the torque limiter.

The stop means are arranged in such a way that the direct stop torque and the retro stop torque are lower than the trip threshold of the torque limiter.

The second member and the intermediate member are rotatably mounted on one another via cylindrical bearing surfaces.

The torque limiter is friction type.

The second element has a bearing surface facing a bearing surface of the intermediate element and the torque limiter comprises an elastic washer which is arranged to exert a load capable of pressing the surface of the intermediate element. supporting the second element against the bearing surface of the intermediate element. One of the second element and the intermediate element is covered by an anti-wear and coefficient of friction stabilizer coating. By way of example, one of the second element and the intermediate element is nickel-plated, which makes it possible to limit its wear as well as the variations of the coefficient of friction opposing the relative movement of the second element relative to the intermediate element.

The torque limiter comprises a support washer fixed on the intermediate element and the spring washer is interposed axially between the support washer and the second element.

The elastic damping means comprise at least one elastic blade fixed on one of the intermediate element and the first element and cooperating with a support element carried by the other of the intermediate element and the first element. Since such elastic means are particularly sensitive to over-couples, the use of the torque limiter and abovementioned abutment means is particularly advantageous in combination with these elastic means.

The elastic damping means comprise at least one elastic blade fixed on the intermediate element and cooperating with a support element carried by the first element, said at least one elastic blade and the support washer of the torque limiter are fixed on the intermediate element by common fasteners.

According to one embodiment, one of the first element and the second element is a secondary flywheel of a double damping flywheel intended to form a reaction plate for a clutch device and the other one of the first element and the second element forms with the intermediate element a primary flywheel of the double damping flywheel.

The primary flywheel has a hub on which is rotated the secondary flywheel.

According to one embodiment, the first element is a primary flywheel of a double damping flywheel intended to be fixed to a crankshaft of an engine and the intermediate element and the second element together form a secondary flywheel double damping flywheel. The intermediate element is rotatably mounted on the first element via a bearing and has a bearing surface on which is rotatably mounted the second element. The second element is intended to form a reaction plate for a clutch device.

According to one embodiment, the intermediate element comprises tabs extending radially outwards and the abutment means comprise abutment surfaces carried by said tabs and adapted to cooperate with abutment surfaces carried by the first element when the first element and the intermediate element reach their relative end positions.

According to another embodiment, the abutment means comprise a finger carried by the intermediate element and projecting axially towards the first element and adapted to cooperate with abutment surfaces carried by the first element when the first element and the element. intermediary reach their relative positions at the end of the race.

The finger is movable within a groove formed in the first element and the circumferentially opposite ends of the groove each comprise an abutment surface adapted to cooperate with the finger.

According to a second embodiment, the first element is a secondary flywheel of a double damping flywheel intended to form a reaction plate for a clutch device and the intermediate element and the second element together form a steering wheel. primary inertia of the double damping flywheel. The second element and the first element are rotated relative to each other by means of a bearing and the second element has a bearing surface on which is rotatably mounted the intermediate element.

The elastic damping means comprise at least one resilient blade integral in rotation with one of the first element and intermediate element and cooperating with a support element carried by the other of said first element and intermediate element; the elastic blade being arranged such that, in a relative angular position different from a relative position of rest, the support element exerts a bending force on the elastic blade producing a reaction force opposite the elastic blade on the support element, this reaction force having a circumferential component adapted to return said first element and intermediate element to said relative position of rest. - The resilient blade has a cam surface and the support member has a cam follower arranged to cooperate with the cam surface.

The cam follower moves on the elastic blade when the elastic blade is deformed to dampen the acyclisms. In this case, the invention makes it possible to predetermine the position of the cam follower on the cam when the torque limiter is triggered.

The cam follower is a roller mounted to rotate on the first element or the intermediate element, for example by means of a rolling bearing. The support element is arranged radially outside the elastic blade. Such an arrangement makes it possible to retain the elastic blade radially when it is subjected to centrifugal force.

The elastic blade is arranged to deform in a plane perpendicular to the axis of rotation X.

The elastic blade is arranged to deform to dampen acyclisms.

The elastic blade has a hairpin shape. - Also, the blade has a radially outer flexible strand connected by a bent portion to a radially inner fixing strand.

The radially inner fixing strand is mounted to rotate with the intermediate element and the finger is arranged on the intermediate element radially between the inner fixing strand and the flexible outer strand. The interior space of the damper is thus advantageously used.

According to one embodiment, the invention also provides a motor vehicle comprising a torque transmission device mentioned above.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood, and other objects, details, features and advantages thereof will become more clearly apparent from the following description of several particular embodiments of the invention, given solely for the purposes of the invention. illustrative and not limiting, with reference to the accompanying drawings. - Figure 1 is a sectional view of a double damping flywheel equipped with blade damping means according to a first embodiment. - Figure 2 is a sectional view of the double damping flywheel of Figure 1 passing through a stop adapted to limit the relative rotation of the primary flywheel relative to the flywheel secondary. FIG. 3 is a sectional view of the double damping flywheel of FIGS. 1 and 2; FIG. 4 is another sectional view of the double damping flywheel of FIGS. 1 to 3; FIG. 5 is a front view of FIG. a double damping flywheel according to a second embodiment in which the secondary flywheel is only partially shown in order to allow a visualization of the damping means and the stops acting between the primary flywheel and the steering wheel. secondary inertia. - Figure 6 is a half-sectional view of the double damping flywheel of Figure 5. - Figure 7 is a sectional view of a double damping flywheel according to a third embodiment. FIG. 8 is a perspective view of the rear face of the primary flywheel of the double damping flywheel of FIG. 7. FIG. 9 is a perspective view of the front face of the secondary flywheel of the double damping flywheel of FIG.

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 torque transmission device. By convention, the "radial" orientation is directed orthogonally to the X axis of rotation of the torque transmission device determining the "axial" orientation and, from the inside towards the outside away from said axis, the "Circumferential" orientation is directed orthogonal to the axis of the torque transmission device and orthogonal to the radial direction. The terms "external" and "internal" are used to define the relative position of one element with respect to another, with reference to the X axis of rotation of the torque transmission device, an element close to the axis is thus described as internal as opposed to an external element located radially at the periphery. Furthermore, the terms "rear" AR and "front" AV are used to define the relative position of one element relative to another in the axial direction, an element intended to be placed close to the engine being designated by before and an element intended to be placed close to the gearbox being designated by the rear.

In relation with FIGS. 1 to 4, on the one hand, and with FIGS. 5 and 6, on the other hand, two embodiments of double damping flywheel are represented. Each double damping flywheel 1 comprises a primary flywheel 2, intended to be fixed at the end of a crankshaft of a combustion engine, not shown, and a secondary flywheel 3 which is centered and guided on the steering wheel. primary 2 by means of a bearing 4, such as a rolling bearing with balls. 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 primary flywheel 2 comprises a radially inner hub 5 supporting the bearing 4, an annular portion 6 extending radially from the hub 5 and a cylindrical skirt 7 extending axially rearwardly from the outer periphery of the annular portion. 6. The primary flywheel 2 is provided with orifices for the passage of fastening screws 8, for fixing the primary flywheel 2 on the crankshaft of the engine. The primary flywheel 2 carries, on its outer periphery, a ring gear 9 for driving in rotation of the primary flywheel 2, using a starter.

The secondary flywheel 3 comprises a flat annular surface 10, turned towards the rear, intended to form a bearing surface for a friction lining of a clutch disk, not shown. The secondary flywheel 3 has, close to its outer edge, pads 11 and orifices 24, shown in Figures 3 and 4, for mounting a cover of the clutch device.

In the embodiments illustrated in Figures 1 to 6, the secondary flywheel 3 is formed in two parts: namely an outer plate 3a which has the flat annular surface 10 for forming the bearing surface for a clutch disc and a central portion 3b forming a hub for the outer plate 3a.

The central portion 3b is mounted on the hub 5 of the primary flywheel 2 with the interposition of the rolling bearing 4. To this end, the inner portion of the central portion 3b has a housing for receiving the outer ring of the rolling bearing 4. receiving housing of the outer ring of the rolling bearing 4 is delimited at the rear by a shoulder for retaining the outer ring.

The outer plate 3a is rotatably mounted on the central portion 3b. To do this, the central portion 3b has a cylindrical bearing surface 16 cooperating with a complementary cylindrical surface 17 formed on a radially inner edge of the outer plate 3a so that the central portion 3b forms a hub for the outer plate 3a. The central portion 3b comprises a web 18 which develops radially outwards with respect to the cylindrical bearing surface 16. The web 18 forms a bearing surface 19 which cooperates with a bearing surface 20 of the outer plate 3a so as to limit the forward movement of the outer plate 3a.

The double damping flywheel 1 also comprises a torque limiter 21 interposed between the central portion 3b and the outer plate 3a. The torque limiter 21 makes it possible to rotate the central portion 3b and the outer plate 3a so as to transmit the torque integrally between the central portion 3b and the outer plate 3a as long as the torque applied to the central portion 3b or the outer plate 3a is below a trip threshold of the torque limiter. When the torque acting on the central portion 3b or the outer plate 3a is greater than or equal to the tripping threshold, the torque limiter 21 then allows a relative rotation of the outer plate 3a relative to the central portion 3b so that the torque is not fully transmitted. Such a torque limiter 21 thus makes it possible to limit the torque passing through the transmission of the motor vehicle so as to protect equipment sensitive to overtaxes.

In the embodiment shown, the torque limiter 21 is of the friction type. The torque limiter 21 comprises a support washer 22 fixed on the central portion 3b and an elastic washer 23, Belleville type washer for example.

The support washer 22 is formed in a metal sheet. The support washer 22 is fixed on the central portion 3b by means of a plurality of rivets 25. The support washer 22 has two orifices 26, in particular represented in FIG. 4, through which tabs 27 of the spring washer pass. 23 which extend radially inward. Thus, the elastic washer 23 is secured in rotation to the support washer 22 and therefore to the central portion 3b of the secondary flywheel 3. Additional orifices and lugs may be provided if desired.

The spring washer 23 is housed in a stall formed at the inner edge of the rear surface of the outer plate 3a. The spring washer 23 is interposed axially between the support washer 22 and the outer plate 3a. The spring washer 23 thus exerts an axial load on the outer plate 3a so as to press against the web 18 of the central portion 3b. Thus, a friction resisting torque whose value is determined in particular by the load of the spring washer 23 is exerted between the bearing surface 19 of the web 18 and the bearing surface 20 of the outer plate 3a. As long as a torque exerted on the outer plate 3a or the central part 3b has a value lower than the trigger threshold of the pressure limiter, the torque is not sufficient to overcome this friction-resistant torque so that the outer plate 3a remains in rotation with the central portion 3b. On the contrary, when a torque exerted on the outer plate 3a or the central portion 3b takes a value greater than or equal to the tripping threshold of the torque limiter, the torque exerted is sufficient to overcome the friction resisting torque so that that the outer plate 3a is rotated relative to the central portion 3b. The entire torque acting on the outer plate 3a or the central portion 3b is then not transmitted between the two parts of the secondary flywheel 3.

According to one embodiment, the central portion 3b is made by forging a steel, such as a 42CD4 steel for example, while the outer plate 3a is made of cast iron, by a casting process.

According to one embodiment, the central portion 3b undergoes a surface treatment to protect it from wear and thus to limit the variations of the coefficient of friction over time. The central portion 3b can in particular undergo a nickel plating treatment. For example, the central portion 3b may be covered with a nickel layer having a thickness of between 5 and 10 .mu.m.

Moreover, the double damping flywheel 1 is also equipped with damping means coupling the primary flywheel 2 and the secondary flywheel 3 so as to allow a transmission of the vibration-damping torque between the primary and secondary flywheels 3. In particular, the damping means elastically couple the primary flywheel 2 to the central portion 3a of the secondary flywheel 3.

In the embodiments shown, the damping means are blade means as described for example in the document FR3008152.

It can thus be seen in FIG. 5 that the resilient damping means comprise two resilient blades 28, 29 curved around the axis of rotation X. The two resilient blades 28, 29 are symmetrical to one another with respect to the axis of rotation X. The resilient blades 28, 29 are here fixed on the central portion 3b of the secondary flywheel 3. According to other embodiments not shown, the damping means comprise more blades, for example 3, 4, 5 or 6.

As represented in FIGS. 1 and 3, the elastic blades 28, 29 are fixed on the central part 3b of the secondary flywheel by means of the rivets 25 which allow the fixing of the support washer 22 to the central part 3b of the secondary flywheel. 3, which limits the number of components.

Each elastic blade 28, 29 has a cam surface which is arranged to cooperate with a support element formed by a cam follower 30 carried by the primary flywheel 2. The cam followers 30 are here rollers 31 rotatably mounted mounted on the primary flywheel 2. The cam followers 30 are held in abutment against their respective cam surfaces and are arranged to roll against said cam surface during a relative rotation between the primary and secondary flywheels 3. cam followers 30 are disposed radially outwardly from their respective cam surfaces so as to radially maintain the resilient blades 28, 29 when subjected to centrifugal force.

Each cam surface is arranged such that, for a relative rotation between the primary flywheel 2 and the secondary flywheel 3 in one direction or the other, relative to a relative angular position of rest, the cam follower 30 associated moves on the cam surface and, in doing so, exerts a bending force on the resilient blade 28, 29. By reaction, the resilient blade 28, 29 exerts on the cam follower 30 a restoring force having a circumferential component which tends to bring the primary flywheels 2 and secondary 3 to their relative angular position of rest. Thus, the resilient blades 28, 29 are capable of transmitting 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). Moreover, the torsional vibrations and the irregularities of torque which are produced by the engine and transmitted by the crankshaft to the primary flywheel 2 are damped by the flexion of the elastic blades 28, 29.

As represented for example in FIG. 1, the rollers 31 are advantageously rotatably mounted on the primary flywheel 2 by means of rolling elements, such as balls, rollers or needles, so as to reduce parasitic friction. likely to affect the depreciation function. The rollers 31 are each carried by a cylindrical rod 32 extending parallel to the axis of rotation X and one end of which is fixed inside a bore formed in the primary flywheel 2. According to another embodiment, As shown, the cam follower is in the form of a plain bearing.

In an alternative embodiment not shown, the structure is reversed and the resilient blades 28, 29 are fixed on the primary flywheel 2 while the rollers 31 are carried by the central portion 3a of the secondary flywheel 3.

Furthermore, although the invention is described above in relation to blade damping means, it is also possible to use damping means with helical elastic members, as described for example in documents FR2969730 or FR2936290. The damping means may comprise curved helical springs as in the aforementioned document FR2969730, curved coil springs and straight coil springs arranged in pairs in series as in the aforementioned document FR2936290 or only straight coil springs arranged in series and commonly designated by the acronym LTD for "long travel damper" in English. It is also possible to use damping means with helical elastic members with radial orientation.

Moreover, the double damping flywheel 1 comprises stop means capable of limiting the relative rotation between the primary flywheel 2 and the central portion 3b of the secondary flywheel 3 between a first and a second relative limit positions. The first relative limit position is reached as soon as a torque transmitted in a retro direction - that is to say from the secondary flywheel to the primary flywheel - takes a value greater than or equal to a threshold, called a torque of retro stop. The second relative position of end of stroke is reached as soon as a torque transmitted in a direct direction - that is to say from the primary flywheel to the secondary flywheel - has a value greater than or equal to a threshold, named direct stop torque. Thus, the elastic damping means are protected and the torque likely to pass through the resilient damping means are necessarily less than the direct stop torque, in the forward direction, and less than the reverse stop torque, in the direction retro.

Advantageously, the direct and reverse stop couples are lower than the trigger thresholds of the pressure limiter, which makes it possible to ensure that the pressure limiter is triggered for relative positions of the primary flywheel 2 and the central portion 3b. of the secondary flywheel 3 corresponding to the end positions.

According to the embodiment shown in Figures 2, 3 and 4, the abutment means comprise one or more fingers 33 developing axially from the web 18 of the central portion 3b of the secondary flywheel 3. Each finger 33 is movably mounted to the interior of a groove 34 formed in the rear surface of the primary flywheel 2. The circumferentially opposite ends of the groove 34 each comprise an abutment surface 41, shown in Figure 4, adapted to cooperate with the finger 33 associated with to limit the relative rotation of the central portion 3b of the secondary flywheel 3 with respect to the primary flywheel 2.

The double damping flywheel of Figures 5 and 6 differs from that of Figures 1 to 4 by the structure of its abutment means. As shown in FIG. 5, the central part 3b of the secondary flywheel 3 comprises tabs 35 that develop radially outwards. Each lug 35 has abutment surfaces 36, 37 which develop radially at its circumferentially opposite ends. The abutment surfaces 36, 37 are each intended to cooperate with an abutment surface 38 carried by the primary flywheel 2 when a driving torque transmitted from the primary flywheel 2 to the secondary flywheel 3 reaches a value greater than or equal to the torque of direct stop and with another abutment surface 39 carried by the primary flywheel 2 when a resisting torque, transmitted from the secondary flywheel to the primary flywheel, reaches a value greater than or equal to the retro-stopping torque. In FIG. 5, the relative rotation of the primary flywheel 2 with respect to the secondary flywheel 3 in the forward direction is illustrated by the arrow D while the relative rotation of the primary flywheel 2 with respect to the secondary flywheel 3 in the retro direction is illustrated by FIG. the arrow R. Stop means having such a structure allow, by comparison with those of Figures 1 to 4, to have the abutment surfaces further from the axis of rotation X, which limits the forces exerted on the stop means when they arrive at the end of the race.

It can also be seen in FIG. 5 that the lugs 35 may be equipped with bores 40 in order to limit their inertia.

Figures 7 to 9 illustrates a double damping flywheel according to a third embodiment. Elements identical or similar to the elements of Figures 1 to 6, that is to say, performing the same function, have the same reference number increased by 100.

The double damping flywheel 101 illustrated in FIGS. 7 to 9 differs from the damping double flywheels 1 according to the embodiments described above in that it is the primary flywheel 102 of the double damping flywheel 1 which is formed in two parts 102a, 102b between which is interposed a torque limiter 142.

In this case, the primary flywheel 102 comprises a central portion 102a intended to be fixed at the end of a crankshaft of a combustion engine and an outer portion 102b rotatably mounted on the central portion 102a.

In such an embodiment, the elastic damping means and the abutment means act between the outer portion 102b of the primary flywheel 102 and the secondary flywheel 103. Thus, in the embodiment shown, the cam followers 130 are mounted rotatably on the outer portion 102a of the primary flywheel 102 and each cooperate with an elastic blade 128, 129 fixed to the secondary flywheel 103. Furthermore, the abutment means comprises elements 143, shown in Figure 9, protruding towards the rear of the secondary flywheel 103 and able to cooperate with abutment surfaces 138, 139, illustrated in FIG. 8, carried by the external part 102b of the primary flywheel 102, in order to limit the relative angular displacement between the external part 102b the secondary flywheel 102 and the primary flywheel 103.

Furthermore, as illustrated in Figure 7, the outer edge of the central portion 102a is received in a shoulder 144 formed at the inner edge of the outer portion 102b. The shoulder 144 has, firstly, an axial bearing surface 145 which cooperates with a bearing surface 146 of the central portion 102a so as to limit the rearward movement of the outer portion 102b relative to the central portion 102a and, secondly, a cylindrical surface 147 cooperating with a cylindrical bearing surface 148 formed on the outer periphery of the central portion 102a.

The torque limiter 142 has a similar operation to the torque limiter 21 described above. It comprises a support washer 149 fixed on the outer portion 102b and a spring washer 150 of the Belleville washer type. The support washer 149 is fixed on the outer part 102b by means of a plurality of rivets 151. The support washer 149 has orifices 152 through which tabs 153 of the elastic washer 150 which extend radially towards inside. The spring washer 150 is interposed axially between the support washer 149 and the central portion 102a of the primary flywheel 102 and thus exerts an axial load on the central portion 102a so as to press against the outer portion 102b.

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.

In particular, if the invention is described above in relation to a double damping flywheel, it is also applicable to other torsion dampers and in particular to torsion dampers adapted to be used in the transmission chains of hybrid vehicles. 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 "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 (15)

1. Torque transmission device for a vehicle transmission chain; said torque transmission device comprising: - a first member (2, 103) and a second member (3a, 102a) movable in rotation relative to each other about an axis of rotation X; and - an intermediate element (3b, 102b) disposed in a torque transmission path between the first element (2, 103) and the second element (3a, 102a); the intermediate element (3b, 102b) being movable in rotation relative to the first element (2, 103) around the axis of rotation X and being elastically coupled to the said first element (2, 103) by elastic means; damping (28, 29, 128, 129) so as to allow vibration-damped torque transmission between the first member (2, 103) and the intermediate member (3a, 102b); the intermediate element (3b, 102b) being rotatable relative to the second element (3a, 102a) around the axis of rotation X and being associated with said second element (3a, 102a) by a torque limiter (21 , 142), the torque limiter (21, 142) being arranged to rotate the intermediate element (3b, 102b) and the second element (3a, 102a) in rotation when a torque transmitted between the intermediate element (3b, 102b) and the second element (3a, 102a) has a value less than a trip threshold of the torque limiter and to allow relative rotation between the intermediate element (3b, 102b) and the second element (3a, 102a) when a torque applied to the intermediate element (3b, 102b) or the second element (3a, 102a) has a value greater than or equal to said tripping threshold so as to limit the torque transmitted between the intermediate element (3b, 102b) and the second element (3a, 102a); said torque transmission device being characterized in that it comprises stop means (33, 34, 35, 38, 39, 143, 138, 139) able to limit the relative rotation of the first element (2, 103) by relative to the intermediate element (3b, 102b) in at least one relative end position, said relative end position being intended to be reached for a torque transmitted between the first element (2, 103) and the intermediate element (3b, 102b) in a first direction taking a value greater than or equal to a stopping torque, said stop means being arranged such that the stopping torque is less than the trigger threshold of the torque limiter. 2. torque transmission device according to claim 1, wherein the abutment means are adapted to limit the relative rotation of the first element relative to the intermediate element between two relative end positions; the two relative end-of-travel positions being intended to be respectively reached for a torque transmitted between the first element (2, 103) and the intermediate element (3b, 102b) in a first direction taking a value greater than or equal to a couple retro-stop and for a torque transmitted between the first element and the intermediate element, in a second direction opposite to said first direction, taking a value greater than or equal to a direct stop torque; said stop means being arranged such that the direct stop torque and the reverse stop torque are lower than the trip threshold of the torque limiter. A torque transmitting device according to claim 1 or 2, wherein the second member (3a, 102a) and the intermediate member (3b, 102b) are rotatably mounted to each other via bearing surfaces. cylindrical (16, 17, 147, 148). 4. Torque transmission device according to any one of claims 1 to 3, wherein the second member (3a, 102a) has a bearing surface (20, 146) vis-à-vis a surface d support (19, 145) of the intermediate element (3b, 102b) and wherein the torque limiter (21, 142) comprises an elastic washer (23, 150) which is arranged to exert a load capable of plating the surface bearing (20, 146) of the second member (3a) against the bearing surface (19, 145) of the intermediate member (3b, 102b). A torque transmission device according to claim 4, wherein one of the second member (3a, 102a) and the intermediate member (3b, 102b) is covered by an anti-wear and friction coefficient stabilizer coating. for example a nickel plating. Torque transmission device according to claim 4 or 5, wherein the torque limiter (21, 142) comprises a support washer (22, 149) fixed to the intermediate element (3b, 102b) and in which the spring washer (23) is interposed axially between the support washer (22, 149) and the second element (3a, 102a). 7. Torque transmission device according to any one of claims 1 to 6, wherein the resilient damping means comprise at least one elastic blade (28, 29) fixed on one of the intermediate element (3b). and the first element (2) and cooperating with a support element (30) carried by the other one of the intermediate element (3b) and the first element (2). 8. Device according to claim 7, wherein the elastic blade (28, 29) is fixed on the intermediate element (3b) and the bearing element (30) is carried by the first element (2). 9. Device according to claims 6, 7 and 8 taken in combination, wherein said at least one elastic blade (28,29) and the support washer (22) of the torque limiter (21) are fixed on the intermediate element (3b) by common fasteners (25). 10. Torque transmission device according to any one of claims 1 to 9, wherein the first element (2) is a primary flywheel of a double damping flywheel intended to be fixed to a crankshaft of an engine. , wherein the intermediate element (3b) and the second element (3a) together form a secondary flywheel (3) of the double damping flywheel, the intermediate element (3b) being rotatably mounted on the first element (2). ) via a bearing (4) and having a bearing surface (16) on which is rotatably mounted the second member (3a) and wherein the second member (3a) is adapted to form a reaction plate for a clutch device. Torque transmission device according to claim 10, in which the intermediate element (3b) comprises tabs (35) extending radially outwards and in which the abutment means comprise abutment surfaces (36, 37) carried by said tabs (35) and adapted to cooperate with abutment surfaces (38, 39) carried by the first element (2) when the first element (2) and the intermediate element (3b) reach their relative positions. end of race. 12. torque transmission device according to claim 10, wherein the abutment means comprise a finger (33) carried by the intermediate member (3b) and projecting axially towards the first member (2) and adapted to cooperate with stop surfaces carried by the first member (2) when the first member (2) and the intermediate member (3b) reach their relative end positions. A torque transmission device according to claim 12, wherein the finger (33) is movable within a groove in the first member (2) and wherein the circumferentially opposite ends of the groove (34). each comprise an abutment surface adapted to cooperate with the finger (33). A torque transmission device according to any one of claims 1 to 9, wherein the first member (103) is a secondary flywheel of a double damping flywheel (101) for forming a reaction plate for a clutch device, in which the intermediate element (102b) and the second element (102a) together form a primary flywheel (120) of the double damping flywheel, the second element (102a) and the first element (103a). ) being rotatably connected to each other via a bearing (104) and the second member (102a) having a bearing surface (147) on which is rotatably mounted the intermediate member (102b) .. 15. Motor vehicle equipped with a torque transmission device according to any one of claims 1 to 14.