Torque transmission system

Abstract

The invention relates to a torque transmission system (100) comprising: - a torsional oscillation damper (300) comprising elastic members (304); - an additional inertial mass (9) attached to the torsional oscillation damper (300); - a torque output element (302) rotatably connected to an input element of a gearbox; - a clutch (1) for selectively coupling the torsional oscillation damper (300) to the torque output element (302); - a transmission ring gear (80) connected to the torque output element (302) and co-operating with a rotor shaft of a rotary electric machine; wherein the elastic members (304), the additional inertial mass (9) and the transmission ring gear (80) are axially arranged opposite one another, and the elastic members (304) are positioned radially outside the clutch (1).

Description

Description Title of the invention: Torque transmission system Technical field [1] The present invention relates to the field of transmissions for motor vehicles. It relates in particular to a torque transmission system intended to be arranged in the powertrain of a motor vehicle, between an internal combustion engine and a gearbox. [2] It relates more specifically to a torque transmission system for a hybrid type motor vehicle in which a rotating electric machine is arranged in the drive train. Technological background [3] In the state of the art, hybrid-type motor vehicles are known comprising a torque transmission system arranged between an internal combustion engine (also called a "thermal engine"] and a gearbox, a rotating electrical machine and a clutch for rotatingly coupling or uncoupling a crankshaft of the internal combustion engine to a rotor shaft of the rotating electrical machine. Thus, it is possible to couple the internal combustion engine each time the vehicle stops and to restart it using the rotating electrical machine. The rotating electrical machine can also constitute an electric brake or provide additional energy to the internal combustion engine to assist it or prevent it from stalling. When the internal combustion engine is in operation, the electric machine can act as an alternator.The rotating electric machine can also provide the vehicle's drive independently of the internal combustion engine. [4] Such a rotating electrical machine may be in line with the torque transmission system, i.e. the axis of rotation of the rotor of the rotating electrical machine coincides with the axis of rotation of the torque transmission device. Alternatively, the rotating electrical machine may be offset from the torque transmission system, i.e. the axis rotation of the rotor of the rotating electrical machine is offset from the rotation axis of the torque transmission device. [5] An internal combustion engine exhibits acyclisms due to successive explosions in the engine cylinders. In order to filter the vibrations generated by the acyclisms of the internal combustion engine, it is known to integrate torsional oscillation dampers with elastic members into the aforementioned transmission assemblies. Without such dampers, vibrations penetrating into the gearbox would cause particularly undesirable shocks, noise or sound pollution during operation. Such dampers are conventionally arranged between the internal combustion engine and the rotating electrical machine. Such a device is for example disclosed in document DE102019129313 Al. [6] In current developments in the hybridization of motor vehicles, it is required to have a transmission chain integrating an electrical energy source without this impacting the axial and radial compactness of said transmission chain. This search for compactness is the basis of the invention. [7] In this logic, the torque transmission device between the thermal engine and the electric machine described in document DE102019129313 A1 is not fully satisfactory. Indeed, it includes a large diameter torsional oscillation damper and a means of connection to the rotating electric machine axially offset from the clutch, which results in an overall size that is not compatible with market expectations. Summary [8] The invention aims to provide a torque transmission system that reconciles the requirements of axial and radial compactness without, however, degrading the filtration of torsional oscillations. [9] The invention achieves this using a torque transmission system, in particular for a motor vehicle, having a first axis of rotation and comprising: - a torsional oscillation damper comprising a primary support pivoting about the first axis of rotation and capable of being connected in rotation to a crankshaft of an internal combustion engine, a secondary support, and elastic members elastically coupling in rotation the primary support to the secondary support; - an additional inertia mass fixed integrally to the torsion oscillation damper; - a torque output element pivoting around the first axis of rotation and capable of being linked in rotation, directly or indirectly, to at least one input element of a gearbox; - a clutch selectively coupling the secondary support of the torsional oscillation damper with the torque output element; and - a transmission ring gear connected in rotation to the torque output element and configured to cooperate in rotation, directly or indirectly, with a rotor shaft of a rotating electrical machine; the elastic members, the additional inertia mass and the transmission ring gear being arranged axially opposite each other, the elastic members being axially positioned between the additional inertia mass and the transmission ring gear, the elastic members being radially positioned outside the clutch.

[0010] This structure significantly improves the compactness of the torque transmission system by allowing radial stacking of the elastic members and the transmission crown with the clutch, which therefore reduces the axial size of the torque transmission system. In addition, the use of an additional inertia mass advantageously ensures the filtration of torsional oscillations without having to resort to a large diameter torsional oscillation damper.

[0011] For the purposes of this application: - “axially” means “parallel to the first axis of rotation”; - “radially” means “along an axis belonging to a plane orthogonal to the first axis of rotation and intersecting this first axis of rotation”; - “circumferentially” means “around the first axis of rotation”; - parts are said to be “axially opposite” when they are all crossed by the same right circular cylindrical surface having as its axis of revolution the first axis of rotation and offset from each other parallel to this first axis of rotation; - two parts are said to be "rotationally connected" when they are "assembled so as not to rotate relative to each other". In other words, it is a rotationally integral connection, possibly with very little play such as a groove play. This connection can be made between the first part and the second part directly or by means of one or more intermediate parts; - two parts are said to be "fixed" when they are permanently immobilized relative to each other, this immobilization being able to result from a fixing of the first part on the second part directly or by means of one or more intermediate parts.

[0012] According to an additional characteristic of the invention, the elastic members axially cover the clutch.

[0013] According to an additional characteristic of the invention, the additional inertia mass is an added part fixed to the torsion oscillation damper by a fixing means, in particular by welding, by shrinking, by screwing, by riveting or by crimping.

[0014] According to one aspect of the invention, the elastic members of the torsional oscillation damper are straight helical springs.

[0015] According to another aspect of the invention, the elastic members of the torsional oscillation damper are curved helical springs.

[0016] According to another aspect of the invention, the elastic members of the torsional oscillation damper are helical springs arranged in series.

[0017] These last three characteristics make it possible to adapt the type of springs according to the torsional stiffness targeted for the torsional oscillation damper in order to ensure sufficient filtration of the torsional oscillations.

[0018] According to an additional characteristic of the invention, the additional inertial mass is fixed integrally to the primary support.

[0019] Thus, the additional inertia mass can be advantageously positioned axially on the internal combustion engine side and thus free up axial space on the gearbox side in order to accommodate other components such as, for example, elastic members, and thus improve the overall axial compactness of the torque transmission system.

[0020] According to an additional characteristic of the invention, the inertia of the additional inertia mass represents 20 to 70% of the inertia of the torsional oscillation damper.

[0021] Thus, this range of inertia value of the additional inertia mass makes it possible to cover most of the filtration needs of the range of hybrid vehicle applications while maintaining a radially compact torsional oscillation damper.

[0022] The inertia of the shock absorber is equal to the sum of the inertias of the primary support, the secondary support, and the elastic members. The unit of inertia is kg.m 2 .

[0023] According to an additional characteristic of the invention, the primary support is made from a metal sheet having a first thickness, the additional inertial mass having a second thickness equal to its largest axial dimension, the second thickness being greater than 1.5 times the first thickness.

[0024] Thanks to this feature, the primary support and the additional inertia mass can be produced simply and economically by a process adapted to their specific dimensions. The primary support can be produced for example by a process of stamping and / or folding a steel sheet. The additional inertial mass can be produced for example by a rolling and / or machining process more suited to its high thickness.

[0025] The first thickness of the primary support is measured in a raw portion of it, that is to say in a portion which has not undergone any operation locally modifying the initial thickness of the metal sheet, such as for example machining.

[0026] According to an additional characteristic of the invention, the primary support comprises a central portion extending radially, the central portion and the additional inertial mass overlapping axially.

[0027] This latter characteristic contributes to obtaining a reduced axial size, but also to avoiding a significant axial offset of the additional inertia mass which, under the effect of centrifugal forces, would cause bending moments harmful to the mechanical strength of the torsional oscillation damper.

[0028] According to an additional characteristic of the invention, the primary support comprises at least one drive arm configured to transmit a torque from the primary support to the elastic members, said at least one drive arm projecting axially and being arranged circumferentially between the elastic members.

[0029] According to an additional characteristic of the invention, the secondary support has a shape adapted to retain the elastic members radially and / or axially.

[0030] Thus, the last two characteristics advantageously make it possible to give the torsional oscillation damper a compact and simple to manufacture structure, by giving the function of supporting the elastic devices to the secondary support, thus making it possible to simply arrange the fixing of the additional mass of inertia on the primary support.

[0031] According to an additional characteristic of the invention, the secondary support has a shape adapted to radially and / or axially retain the elastic members, said adapted shape comprising a first wall axially facing the elastic members and a second wall directly radially above the elastic members.

[0032] According to an additional characteristic of the invention, said adapted shape of the secondary support further comprises a third wall directly radially below the elastic members.

[0033] According to an additional characteristic of the invention, the secondary support is made of a single piece.

[0034] According to an additional characteristic of the invention, the secondary support is formed in a single piece from a strip of metallic material having a constant thickness, in particular from a steel sheet, the first, second and third walls being obtained for example by a folding and / or stamping process.

[0035] Thus, the secondary support can be produced using a simple and economical manufacturing process.

[0036] According to an additional characteristic of the invention, the clutch comprises at least one friction disc, in particular a multi-disc assembly, arranged between an input disc carrier connected in rotation to the secondary support and an output disc carrier connected in rotation to the torque output element.

[0037] The clutch in the form of a multi-disc assembly allows the transmission of a high level of torque when the clutch is fully closed, as well as easy modulation of the level of torque transmitted according to the vehicle's operating conditions thanks to the possibility of sliding the discs between them.

[0038] According to an additional characteristic of the invention, the input disc holder and the output disc holder overlap axially.

[0039] According to an additional characteristic of the invention, the output disc holder comprises internal teeth arranged radially outside the at least one friction disc and linked in rotation with said at least one friction disc, the transmission ring gear being fixed integrally to the output disc holder.

[0040] This latter feature makes it possible to further improve the compactness of the torque transmission system because the output disc carrier as described makes it possible to connect, directly and in the same radial stack, the transmission crown to the torque output element. The axial offset of the transmission crown relative to the clutch, as present in the state of the art, is thus avoided.

[0041] According to an additional characteristic of the invention, the torque transmission system further comprises a clutch actuation system and / or a speed reduction assembly capable of kinematically cooperating in rotation the transmission ring gear with the rotor shaft of the rotating electrical machine.

[0042] The actuation system can be mechanical, electromechanical, electromagnetic, or hydraulic.

[0043] The speed reduction assembly makes it possible to amplify the torque supplied by the rotor shaft of the rotating electrical machine. Advantageously, the speed reduction assembly can be produced, for example, by a set of cylindrical gears kinematically cooperating in rotation with the rotor shaft of the rotating electrical machine. Alternatively, the reduction assembly can also be produced by pulleys driven in rotation by belts, or toothed wheels driven in rotation by chains. One or more reduction stages are possible depending on the desired reduction level. The speed reduction assembly can also be configured to allow several speed ratios.

[0044] According to an additional characteristic of the invention, the rotor shaft of the rotating electrical machine rotates around a second axis of rotation, the second axis of rotation being parallel to the first axis of rotation.

[0045] According to an additional characteristic of the invention, the speed reducer assembly radially surrounds and axially covers all or part of the transmission ring gear.

[0046] Thus, the speed reducer assembly and the torque transmission system are arranged in the same radial stack, thereby increasing the overall axial compactness.

[0047] According to an additional characteristic of the invention, the transmission crown comprises teeth oriented radially outwards configured to cooperate in rotation, directly or indirectly, with a rotor shaft of a rotating electrical machine.

[0048] The invention further relates to a transmission module comprising a torque transmission system as described above and a housing, the torque transmission system being housed in the housing.

[0049] The housing provides protection for the torque transmission system and allows all the components of the transmission module to be combined into a single sub-assembly. Preferably, the housing is made watertight.

[0050] According to an additional characteristic of the invention, the transmission module comprises a predetermined quantity of transmission fluid contained in the casing, the transmission fluid being for example an oil, the predetermined quantity being adapted so that at least a portion of the elastic members and at least a portion of the transmission crown are immersed in the transmission fluid.

[0051] Thanks to this last feature, the lubrication of the elastic members and the transmission crown is ensured. The elastic members and the transmission crown being axially opposite each other, the quantity of transmission fluid to be put in the casing can be reduced.

[0052] The invention further relates to a powertrain comprising a transmission module as defined previously and a rotating electrical machine. Brief description of the figures

[0053] Figure 1 is a representation in a first sectional plane, of a torque transmission system according to an embodiment of the invention.

[0054] Figure 2 is a detail representation in a second sectional plane of the torque transmission system of Figure 1.

[0055] Figure 3 is a detail representation of Figure 1. Description of the embodiments

[0056] In all the figures, identical elements or elements performing the same function have the same reference numbers. The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment or that the features apply only to a single embodiment. Single features of different embodiments may also be combined or interchanged to provide other embodiments.

[0057] Figures 1 to 3 show in cross section a torque transmission system 100 according to one embodiment of the invention. The torque transmission system 100 is part of a drive train of a transmission line of a motor vehicle. The drive train comprises a rotating electrical machine 200 provided with a stator and a rotor. The vehicle can be propelled, depending on requirements, by an internal combustion engine or by the rotating electrical machine 200.

[0058] As illustrated in particular in Figure 1, the torque transmission system 100 has a first axis of rotation X. The torque transmission system 100 comprises a torsional oscillation damper 300 comprising a primary support 301 pivoting about the first axis of rotation X and capable of being connected in rotation to a crankshaft V of an internal combustion engine, a secondary support 310, and elastic members 304 elastically coupling in rotation the primary support 301 to the secondary support 310. In a known manner, the torsional oscillation damper 300 serves to filter the torsional oscillations (or acyclisms) of the internal combustion engine. In the embodiment of Figure 1, the elastic members 304 are four curved helical springs.

[0059] The torque transmission system 100 further comprises an additional inertial mass 9 fixed integrally to the torsional oscillation damper 300. In the embodiment of FIG. 1, the additional inertial mass 9 is in the form of an attached annular crown welded to the primary support 301. The additional inertial mass 9 has a second thickness equal to its largest axial dimension, preferably between 8 and 30 mm.

[0060] In order to ensure the filtration of torsional oscillations in a radially compact size, the inertia of the additional inertia mass 9 may advantageously be between 20 and 70% of the inertia of the torsional oscillation damper 300, the inertia of the additional inertia mass 9 preferably being between 35 and 55% of the inertia of the torsional oscillation damper 300.

[0061] The torque transmission system 100 further comprises a torque output element 302, here in the form of a hub comprising an internal spline, pivoting around the first axis of rotation X and capable of being linked in rotation, directly or indirectly, to at least one input element, for example a splined shaft, of a gearbox BV.

[0062] As illustrated in particular in FIG. 2, the torque transmission system 100 further comprises a clutch 1 selectively coupling the secondary support 310 of the torsional oscillation damper 300 with the torque output element 302.

[0063] The torque transmission system 100 further comprises a transmission ring 80 linked in rotation to the torque output element 302 and configured to cooperate in rotation, directly or indirectly, with a rotor shaft 210 of the rotating electrical machine 200.

[0064] The elastic members 304, the additional inertia mass 9 and the transmission ring 80 are arranged axially opposite each other, the elastic members 304 being axially positioned between the additional inertia mass 9 and the transmission ring 80, the elastic members 304 being positioned radially outside the clutch 1.

[0065] “Axially opposite” means that the elastic members 304, the additional inertia mass 9 and the transmission ring 80 are all crossed by the same right circular cylindrical surface having as its axis of revolution the first axis of rotation X and offset from each other parallel to this first axis of rotation X.

[0066] The primary support 301 may be formed, in particular in one piece, by a stamping and / or folding process from a metal sheet having a first thickness, preferably between 2 and 5 mm. The primary support 301 may comprise a central portion 303 extending radially, the central portion 303 and the additional inertial mass 9 overlapping axially. The primary support 301 may comprise several drive arms 305 configured to transmit a torque from the primary support 301 to the elastic members 304, the drive arms 305 projecting axially and being arranged circumferentially between the elastic members 304.

[0067] As illustrated in particular in FIG. 3, the secondary support 310 may comprise a suitable shape 316 for radially and axially retaining the elastic members 304, said suitable shape 316 being able to comprise a first wall 313 axially facing the elastic members 304, a second wall 314 positioned directly radially above the elastic members and a third wall 315 positioned directly radially below the elastic members 304. The suitable shape 316 may therefore have a generally substantially “U” shape in section. Advantageously, the secondary support 310 may be formed, in particular in one piece, by a stamping and / or folding process from a metal sheet.

[0068] In another embodiment not shown, the primary support 301 may comprise the adapted shape 316 for radially and axially retaining the elastic members 305, and the secondary support 310 may comprise the drive arms 305 projecting axially and arranged circumferentially between the elastic members 304.

[0069] As illustrated in particular in Figure 2, in the center, the primary support 301 can be driven by a crankshaft hub 306 via, for example, rivets 318 (visible in figure 3). The crankshaft hub 306 can extend towards the center by an axial extension portion 307 to cooperate with a casing 70 by means of a needle centering bearing 308 in order to ensure the centering of the primary support 301. An axial bearing 32, formed by an axial needle thrust bearing or a plain axial bearing, can be interposed axially between the crankshaft hub 306 and the casing 70.

[0070] As can be seen in particular in Figure 3, a friction washer 317 can be interposed between the primary support 301 and the secondary support 310 in order to axially position these two parts between them and to take up the axial forces passing through the transmission system 100.

[0071] As illustrated in particular in Figure 2, the clutch 1 may comprise several friction discs 6, to form a multi-disc assembly, arranged between an input disc holder 2 linked in rotation to the secondary support 310 and an output disc holder 3 linked in rotation to the torque output element 302. The input disc holder 2 and the output disc holder 3 may overlap axially.

[0072] The output disc holder 3 may comprise an internal toothing 18 arranged radially outside the friction discs 6 and linked in rotation with the friction discs 6, the transmission ring 80 being fixed integrally to the output disc holder 3.

[0073] The multi-disc assembly of the clutch 1 may comprise several friction discs 6 integral in rotation with the input disc carrier 2, several plates 7 arranged on either side of each friction disc 6, integral in rotation with the output disc carrier 3 and friction linings arranged between the plates 7 and the friction discs 6. The friction linings may be fixed, in particular glued or riveted, on the friction discs 6. Two friction linings may be fixed axially on either side of a friction disc 6.

[0074] In another embodiment not shown, a single friction lining can be fixed on a single axial side of a friction disc 6.

[0075] In another embodiment not shown, a single friction lining can be fixed axially on a single axial side of a friction disc 6 and another friction lining can be fixed on a single axial side of a plate 7.

[0076] The clutch 1 can take a disengaged position and an engaged position in which the plates 7 and the friction discs 6 pinch the friction linings so as to transmit a torque between the input disc carrier 2 and the output disc carrier 3. The output disc carrier 3 can carry an axially fixed reaction element 11 against which the multi-disc assembly is clamped in the engaged position. The reaction element 11 takes the form of a continuous annular crown around the first axis of rotation X. The plates 7 and the friction discs 6 can be radially between a cylindrical skirt 12 of the output disc carrier 3 and a cylindrical skirt 14 of the input disc carrier 2. The cylindrical skirt 14 can carry radially external teeth which cooperate in rotation with the friction discs 6. The clutch 1 can comprise between 2 and 7 friction discs, for example 2 friction discs.

[0077] Of course, other arrangements of friction discs 6 and plates 7 can be envisaged.

[0078] The clutch 1 may also comprise a piston 20 configured to, in the engaged position, tighten the multi-disc assembly, and in the disengaged position, loosen the multi-disc assembly. The piston 20 may press on a counter-disc 29 to tighten the multi-disc assembly. The counter-disc 29 may be rotatably connected to the output disc carrier 3, with the possibility of axial movement.

[0079] The clutch 1 may further comprise an elastic device 36, for example here a Belleville type elastic washer, configured to exert an elastic return force on the piston 20 to maintain the piston 20 in the engaged position. The elastic device 36 is axially supported on the one hand on the end tabs 23 of the piston 20, possibly via a circlip, and on the other hand on the output disc carrier 3. Such a clutch 1 is said to be of the normally closed type.

[0080] The transmission system 100 may further comprise an actuation system 40 for the clutch 1. The actuation system 40 is configured to move axially, against the elastic return force of the device elastic 36, the piston 20 from the engaged position to the disengaged position. The actuation system 40 can be axially supported on the one hand on the piston 20 via a bearing 39 and, on the other hand, on the output disc holder 3. The actuation system 40 can be of the mechanical, electromechanical, electromagnetic, or even hydraulic type.

[0081] In the embodiment of Figures 1 to 3, the actuation system 40 may be formed by a ball ramp 42 which comprises a first ramp 43 and a second ramp 44. A ring holding balls (not shown) is arranged between the first ramp 43 and the second ramp 44. The first ramp 43 is in the form of a crown which bears on the axial bearing 38. This first ramp 43 is connected in rotation, for example via grooves or via a weld 48, to an actuation lever 47. This actuation lever 47 is formed by a wheel which is toothed on the inside to mesh with the second ramp 44 and toothed on the outside to mesh, directly or indirectly, with a pinion which comes out of an actuator motor (not shown).

[0082] As illustrated in Figures 1 and 2, the input 2 and output 3 disc holders may comprise, when approaching the first axis of rotation X, respectively a first radial zone 16 and a second radial zone 15 facing each other, and a first axial bearing 37, formed by an axial needle thrust bearing or a smooth axial bearing, is interposed between the first radial zone 16 and the second radial zone 15 facing each other. A second axial bearing 38, formed by an axial needle thrust bearing or a smooth axial bearing, is interposed between the actuation system 40 of the piston 20 and the second radial zone 15 of the output disc holder 3. The piston 20 cooperates with a bearing 39 mounted on the actuation system 40 so as to make the actuation system 40 cooperate with the piston 20 with freedom of rotation around the first axis of rotation X, of the piston 20 relative to the actuation system 40.The first axial bearing 37, the second axial bearing 38, the bearing 39 mounted on the actuation system 40 and the actuation system 40 are arranged in an axial stack, namely that they are all crossed by the same circular cylindrical surface. straight line having as its axis of revolution the first axis of rotation X and offset from each other parallel to this first axis of rotation X.

[0083] As illustrated in FIG. 1, the transmission system 100 may further comprise a speed reducer assembly 220 capable of kinematically cooperating in rotation the transmission ring gear 80 with the rotor shaft 210 of the rotating electrical machine 200. The rotor shaft 210 may rotate about a second axis of rotation XM parallel to the first axis of rotation X and may be guided in rotation relative to the casing 70 by ball bearings 81. The speed reducer assembly 220 may radially surround and axially cover all or part of the transmission ring gear 80. The speed reducer assembly 220 may be configured to allow several speed ratios. The transmission ring gear 80 is for example welded to the output disc holder 3.In this embodiment, the transmission crown 80 is produced in the form of a toothed wheel which cooperates in rotation with a cylindrical gear 211 linked in rotation to the rotor shaft 210, and together thus form a speed reduction stage.

[0084] The transmission system 100 may be housed in the casing 70 to form a transmission module. The casing 70 is formed by two assembled half-shells 72. A predetermined quantity of transmission fluid may be contained in the casing 70, the transmission fluid being for example an oil, the predetermined quantity being adapted so that at least a portion of the elastic members 304 and at least a portion of the transmission ring 80 are immersed in the transmission fluid. As illustrated in FIG. 3, by defining a level L as being a line parallel to the first axis of rotation X, the predetermined quantity of transmission fluid may be chosen so that the transmission fluid remaining at the bottom of the casing 70 reaches a horizontal plane passing through the level L when the transmission system 100 is not rotating.Thus, a portion of the elastic members 304 and a portion of the transmission crown 80 are radially above this plane passing through the level L. Here the transmission system 100 is said to be “wet”, that is to say that the components housed in the casing 70 are in an oil mist or. partially submerged. Annular seals 98, 99 may be provided to seal the casing 70.

[0085] It is emphasized that all features, as they emerge for a person skilled in the art from this description, the drawings and the attached claims, even if they have been specifically described only in relation to other specific features, both individually and in any combinations, may be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances make such combinations impossible or meaningless.

[0086] The use of the verb “comporter”, “comprendre” and its conjugated forms does not exclude the presence of other elements or other steps than those stated in a claim.

[0087] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

Claims 1. Torque transmission system (100), in particular for a motor vehicle, having a first axis of rotation (X) and comprising: - a torsional oscillation damper (300) comprising a primary support (301) pivoting about the first axis of rotation (X) and capable of being connected in rotation to a crankshaft (V) of an internal combustion engine, a secondary support (310), and elastic members (304) elastically coupling in rotation the primary support (301) to the secondary support (310); - an additional inertia mass (9) fixed integrally to the torsional oscillation damper (300); - a torque output element (302) pivoting around the first axis of rotation (X) and capable of being linked in rotation, directly or indirectly, to at least one input element of a gearbox (BV); - a clutch (1) selectively coupling the secondary support (310) of the torsional oscillation damper (300) with the torque output element (302); and - a transmission ring gear (80) rotatably connected to the torque output element (302) and configured to cooperate in rotation, directly or indirectly, with a rotor shaft (210) of a rotating electrical machine (200); characterized in that the elastic members (304), the additional inertia mass (9) and the transmission ring gear (80) are arranged axially opposite each other, the elastic members (304) being axially positioned between the additional inertia mass (9) and the transmission ring gear (80), the elastic members (304) being positioned radially outside the clutch (1).

2. Torque transmission system (100) according to claim 1, wherein the additional inertial mass (9) is fixedly attached to the primary support (301).

3. Torque transmission system (100) according to any one of the preceding claims, wherein the inertia of the additional inertia mass (9) is between 20 and 70% of the inertia of the torsional oscillation damper (300).

4. Torque transmission system (100) according to any one of the preceding claims, wherein the primary support (301) is made from a metal sheet having a first thickness, the additional inertial mass (9) having a second thickness equal to its axially largest dimension, the second thickness being greater than 1.5 times the first thickness.

5. Torque transmission system (100) according to any one of the preceding claims, wherein the primary support (301) comprises a central portion (303) extending radially, the central portion (303) and the additional inertial mass (9) overlapping axially.

6. Torque transmission system (100) according to any one of the preceding claims, wherein the primary support (301) comprises at least one drive arm (305) configured to transmit a torque from the primary support (301) to the elastic members (304), said at least one drive arm (305) projecting axially and being arranged circumferentially between the elastic members (304).

7. Torque transmission system (100) according to any one of the preceding claims, in which the secondary support (310) comprises a suitable shape (316) for radially and / or axially retaining the elastic members (304), said suitable shape (316) comprising in particular a first wall (313) axially facing the elastic members (304) and a second wall (314) positioned directly radially above the elastic members (304).

8. Torque transmission system (100) according to any one of the preceding claims, in which the clutch (1) comprises at least one friction disc (6), in particular a multi-disc assembly, arranged between an input disc carrier (2) linked in rotation to the secondary support (310) and an output disc carrier (3) linked in rotation to the torque output element (302), in particular the input disc holder (2) and the output disc holder (3) overlapping axially.

9. Torque transmission system (100) according to claim 8, wherein the output disc holder (3) comprises internal teeth (12) arranged radially outside the at least one friction disc (6) and cooperating in rotation with said at least one friction disc (6), the transmission ring gear (80) being fixed integrally to the output disc holder (3).

10. Torque transmission system (100) according to any one of the preceding claims, the transmission system further comprising an actuation system (40) of the clutch (1) and / or a speed reduction assembly (220) capable of kinematically cooperating in rotation the transmission ring gear (80) with the rotor shaft (210) of the rotating electrical machine (200).

11. A transmission module comprising a torque transmission system (100) according to any one of the preceding claims and a housing (70), the torque transmission system (100) being housed in the housing (70).

12. Transmission module according to claim 11, wherein the transmission module comprises a predetermined quantity of transmission fluid contained in the casing (70), the transmission fluid being for example an oil, the predetermined quantity being adapted so that at least a portion of the elastic members (304) and at least a portion of the transmission crown (80) are immersed in the transmission fluid.

13. Powertrain comprising a transmission module according to one of claims 11 and 12 and a rotating electrical machine (200).

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