Torque transmission system

Abstract

A vehicle torque transmission system comprising: a transmission housing (100); a planetary gear train including a planetary gear (4), an outer ring gear (5), a plurality of planetary gears (6) meshing with the planetary gear and the outer ring gear, and a planet carrier (7) on which the planetary gears pivot via bearings (702), the planet carrier having conduits (703) configured to deliver lubricant to the bearings; the transmission housing having a first wall (101) supporting an injection device (18), the injection device having at least one outlet orifice (181) configured to project a jet of lubricant directly to the inlets of the conduits. (Shortcut Figure: 2)

Description

Title of the invention: Torque transmission system technical field

[0001] The present invention relates to the field of torque transmission systems for motor vehicles, particularly for hybrid or electric vehicles. More specifically, the invention relates to the lubrication of a speed reducer using a planetary gear train. Technological background

[0002] Document EP0731291 describes a torque transmission system in the form of a speed reducer that transmits the torque delivered by a rotating electrical machine to the wheels of a vehicle via a planetary gear set and a differential arranged coaxially with the rotating electrical machine. Such a coaxial arrangement improves radial compactness, particularly compared to speed reducers using parallel gear trains. The use of a planetary gear set, and especially a planetary gear set with two-sided planetary gears arranged axially side by side, further improves the compactness of the speed reducer by allowing a high reduction ratio to be achieved in a small footprint.

[0003] However, such a speed reducer structure poses several technical problems, primarily ensuring satisfactory and homogeneous lubrication of the various internal components of the speed reducer. Indeed, the large number of internal components in a confined space make certain areas difficult to access.

[0004] In order to supply lubricant to certain internal components critical to the lifespan of the gearbox, such as the planetary gears, a complex lubricant path is implemented. This path originates from a lubricant inlet in a drive shaft of the planetary gear train and then passes through several successive components via a plurality of channels and / or by surface migration of said components. This complex lubricant path makes it difficult to control the amount of lubricant reaching the internal components of the gearbox. In addition to improving lubrication, the torque transmission system must remain compact, simple, and economical to manufacture. Summary

[0005] In all that follows, ordinal numeral adjectives are used to differentiate features. They do not define the position of a feature. Therefore, for example, a third feature of a product does not mean that the product has a first and / or a second feature.

[0006] An idea underlying the invention is a torque transmission system that makes it possible to solve one or more technical problems of the prior art, for example the aforementioned problems.

[0007] The invention relates to a torque transmission system for a vehicle comprising: • a drive shaft having an axis of rotation; • a transmission casing; and • a planetary train comprising a planetary pinion, an outer ring gear, a plurality of planetary pinions meshing with the planetary pinion and the outer ring gear, and a planet carrier on which the planetary pinions are pivotally mounted via first bearings, the planet carrier or the planetary pinions having a plurality of conduits configured to carry lubricant from inlets of said conduits to the first bearings; the transmission casing comprising a first wall supporting an injection device, the injection device comprising at least one first outlet orifice configured to project a jet of lubricant directly towards at least one of the conduit inlets.

[0008] By "directly," it is meant here that the lubricant jet does not touch any component during its path between at least one first outlet of the injection device and at least one inlet of the channels used to lubricate the first bearings. In other words, it is possible to draw a straight line segment from at least one first outlet of the injection device to at least one inlet of the channels, without passing through any components.

[0009] The use of such an injection device therefore allows easy and unobstructed access of the lubricant to the inlet of the conduits, thus improving the control of the quantity and flow of lubricant supplying the first bearings.

[0010] For the purposes of this application: • “axially” means “parallel to the axis of rotation”; • “Radially” means “along an axis belonging to an orthogonal plane” to the axis of rotation and cutting across this axis of rotation"; • “circumferentially” means “around the axis of rotation”; • “Rotationally linked” means “assembled in such a way that one does not rotate by "relative to the other." In other words, it is a fixed connection in rotation, possibly exhibiting very little play such as spline play; • Two parts are said to be "fixed" when they are permanently immobilized relative to each other; this immobilization may result of a fixing of the first part onto the second part directly or via one or more intermediate parts. • two 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 axis of rotation and offset from each other parallel to this axis of rotation;

[0011] According to a further feature of the invention, the injection device may comprise one or more separate parts in the form of nozzles, tips, or inserts fixed to the transmission housing. Alternatively, the injection device may comprise one or a plurality of holes provided in the first wall of the transmission housing.

[0012] The shape and dimensions of the injection device allow adjustment of the cross-section and direction of the lubricant jet.

[0013] According to an additional feature of the invention, the first wall of the transmission housing is perpendicular to the axis of rotation.

[0014] According to an additional feature of the invention, the transmission housing constitutes a sealed housing in which the components of the transmission system are housed.

[0015] According to an additional feature of the invention, the lubricant jet is injected through at least one first outlet of the injection device at a pressure between 1 and 20 bar, preferably a pressure between 1.5 and 6 bar.

[0016] The lubricant jet is injected under pressure. In other words, its pressure value is adapted to be able to travel directly the distance that separates at least one first outlet orifice of the injection device from at least one inlet of the conduits carrying the lubricant to the first bearings.

[0017] According to an additional feature of the invention, the lubricant jet is pressurized by means of a pump.

[0018] According to an additional feature of the invention, at least one first outlet orifice of the injection device is axially opposite the inlets of the conduits carrying the lubricant to the first bearings.

[0019] This last feature allows the at least one first outlet orifice to be positioned as close as possible to the conduit inlets, thus reducing the risk of loss of some of the lubricant during its passage.

[0020] According to an additional feature of the invention, the axial distance between at least one first outlet orifice and the conduit inlets is between 2 and 30 mm.

[0021] According to a further feature of the invention, a collection device is fixed to the satellite carrier, the collection device being configured to collect a part of the lubricant projected through at least one first outlet of the injection device and to direct the collected lubricant towards the inlets of the conduits.

[0022] Thus, the collection device makes it possible to accumulate a sufficient quantity of lubricant to ensure a regular supply to the first bearings.

[0023] According to a further feature of the invention, the collection device comprises at least one reservoir adapted to receive a determined quantity of lubricant, the at least one reservoir having in its radially internal part an opening, the opening being positioned radially above the at least one first outlet orifice of the injection device.

[0024] According to an additional feature of the invention, the opening of the reservoir axially covers at least one first outlet orifice of the injection device.

[0025] These last two features make it possible to advantageously position the opening of at least one reservoir in the immediate vicinity of at least one first outlet orifice, which makes it possible to collect the lubricant as soon as it exits the injection device and thus further reduce the risks of loss of some of the lubricant during its journey.

[0026] According to a further feature of the invention, a radially innermost point of the opening of at least one tank is positioned radially inside with respect to a radially outermost point of the conduit inlets.

[0027] This last characteristic allows the lubricant to flow efficiently through the conduits under the effect of the centrifugal forces induced by the rotational speed.

[0028] According to a first aspect of the invention, the collection device is monobloc and extends circumferentially over an angle of 360°.

[0029] The one-piece collection device can receive the lubricant projected by at least one first outlet orifice of the injection device regardless of the angular position of the planet carrier relative to the axis of rotation, thus allowing a large quantity of lubricant to be accumulated.

[0030] According to another aspect of the invention, the collection device is composed of several distinct parts, the number of distinct parts preferably corresponding to the number of satellite gears, each distinct part comprising a separate reservoir.

[0031] Compared to a one-piece collection device, the collection device in several separate parts allows for simpler manufacturing and easier assembly on the satellite carrier due to the smaller dimensions of each separate part.

[0032] Furthermore, the multi-part collection device receives the lubricant projected by at least one first outlet orifice of the injection device only at the angular positions of the planet carrier where one of said distinct parts faces axially to at least one first outlet orifice. The quantity of lubricant The amount received by the collection device can be adapted by adjusting the dimensions of the reservoir. In angular positions of the planet carrier where the collection device does not receive lubricant, at least one first outlet orifice of the injection device can be configured to advantageously project the lubricant onto other components of the transmission system, such as the toothed ring or the planetary gear.

[0033] According to one aspect of the invention, the collection device is made of molded plastic material.

[0034] According to another aspect of the invention, the collection device is made of cast metal, in particular cast aluminum

[0035] According to another aspect of the invention, the collection device is made of metal formed from a sheet of steel.

[0036] According to an additional feature of the invention, the collection device is fixed to the satellite carrier by a fastening means, in particular by fitting or by riveting or by screwing or by gluing or by means of a pin.

[0037] According to another aspect of the invention, the collection device is made as a single unit with the satellite carrier.

[0038] According to a further feature of the invention, the satellite carrier is supported by the first wall of the transmission housing via a second bearing, at least one first outlet orifice of the injection device being positioned radially above the second bearing.

[0039] This last feature makes it possible to avoid passing the lubricant jet through the second bearing and thus to project said lubricant jet directly towards the inlets of the conduits.

[0040] According to an additional feature of the invention, the transmission housing comprises an axially projecting cylindrical portion, the cylindrical portion being positioned radially below the opening of at least one reservoir of the collection device and the cylindrical portion axially covering the opening of at least one reservoir of the collection device.

[0041] Thus, part of the lubricant which would be projected onto the first wall of the transmission housing can flow by gravity down said first wall to the cylindrical portion and then flow by gravity into at least one reservoir of the collection device.

[0042] According to a further feature of the invention, the first wall of the transmission housing has ribs and / or channels configured to collect and guide the lubricant towards the cylindrical portion.

[0043] According to a further feature of the invention, the axially projecting cylindrical portion of the transmission housing has a radially internal surface adapted to support the second bearing.

[0044] According to an additional feature of the invention, the injection device has a plurality of first outlet orifices distributed circumferentially, preferably from three to twelve first outlet orifices.

[0045] The plurality of circumferentially distributed outlet ports allows the conduits to be supplied with lubricant regularly and in sufficient quantity.

[0046] According to a further feature of the invention, the injection device comprising at least one second outlet orifice positioned radially below the second bearing.

[0047] According to a further feature of the invention, at least a second output device is configured to project a jet of lubricant towards the planetary gear.

[0048] According to an additional feature of the invention, the injection device has a plurality of second outlet ports distributed circumferentially, preferably from three to twelve first outlet ports.

[0049] Thanks to these last three characteristics, the injection device can supply lubricant in sufficient quantity and regularly to the teeth of the planetary gear and the satellite gears.

[0050] According to an additional feature of the invention: • the torque transmission system also includes a differential housing; • the planetary gear is rotationally linked to the drive shaft; • the satellite carrier is rotationally linked to the differential housing; • The outer toothed ring is fixed to the transmission housing; and • The differential housing is supported by the transmission casing via the minus a third level.

[0051] The structure of the torque transmission system according to this last characteristic makes it possible to produce a speed reducer having a large reduction ratio in a small footprint.

[0052] According to an additional feature of the invention, the satellite carrier is made of the same material as the differential housing.

[0053] Thus, the one-piece design of the planet carrier with the differential housing eliminates a component, thereby simplifying and simplifying the torque transmission system structure. Furthermore, the quality of the planetary gear train is improved because the manufacturing tolerance chain is reduced.

[0054] The invention further relates to a powertrain comprising: • a lubricant; • a torque transmission system as described above; • a rotating electrical machine configured to rotate the drive shaft; • a motor housing containing the rotating electrical machine.

[0055] According to a further feature of the invention, the lubricant is an oil.

[0056] According to a further feature of the invention, the transmission housing is fixed to the engine casing.

[0057] According to an additional feature of the invention, the first wall of the transmission housing also constitutes a wall of the engine housing.

[0058] According to a further feature of the invention, the lubricant projected by at least one first outlet of the injection device comes from the engine casing or from a chamber provided in the engine casing and / or in the transmission casing.

[0059] Therefore, a single common lubricant can be used to serve both for the lubrication and / or cooling of the torque transmission system and the rotating electrical machine.

[0060] According to a further feature of the invention, the lubricant is injected and / or withdrawn from the transmission housing and / or from the engine housing by means of a pump.

[0061] The use of a pump allows for so-called "active" lubrication which ensures the distribution of a localized and limited quantity of lubricant to just what is needed within the powertrain and thus reduces performance losses due to the bubbling of components in the lubricant, unlike so-called "passive" lubrication without a pump which uses a principle of lubrication by gravity requiring a larger quantity of lubricant.

[0062] According to an additional feature of the invention, the rotating electrical machine is coaxial with the drive shaft.

[0063] This structure makes it possible to improve the overall compactness of the powertrain, while ensuring efficient lubrication of the components of said powertrain thanks to the invention as described above.

[0064] The torque transmission system according to the invention may have one or more of the characteristics described below, either combined or taken independently of each other: • the first bearing and / or the second bearing and / or the third bearing are needle bearings or ball bearings or roller bearings or plain bearings. • Each satellite gear is a double satellite gear comprising a large satellite gear and a small satellite gear having a diameter less than large satellite pinion, the large satellite pinion and the small satellite pinion being linked in rotation and arranged axially side by side, the large satellite pinion being meshed with the planetary pinion and the small satellite pinion being meshed with the outer toothed ring; • the differential gear set is formed by bevel gears, or by straight gears with helical or straight teeth, or by worm gears, or by cylindrical gears arranged in the form of a planetary train; • the differential is a self-locking or limited-slip type differential. Brief description of the figures

[0065] [Fig.1] Fig.1 is a broken cross-sectional view of a powertrain comprising an embodiment of a torque transmission system according to the invention.

[0066] [Fig.2] Fig.2 is a broken cross-sectional view of an embodiment of a torque transmission system according to the invention.

[0067] [Fig.3] [Fig.3] is an enlarged view of [Fig.2].

[0068] [Fig.4] Fig.4 is an isometric view of a planetary gear train of a mode of implementation of a torque transmission system according to the invention.

[0069] [Fig.5] The [Fig.5] is an isometric cross-sectional view of a transmission housing of an embodiment of a torque transmission system according to the invention.

[0070] [Fig.6] The [Fig.6] is an isometric view of a collection device of an embodiment of a torque transmission system according to the invention. Description of the implementation methods

[0071] In all the figures, identical elements or elements performing the same function are identified by the same reference numerals. The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference numeral relates to the same embodiment or that the features apply only to a single embodiment. Simple features from different embodiments can also be combined or interchanged to provide other embodiments.

[0072] Figure 1 illustrates a powertrain 10 according to an embodiment of the invention. The powertrain 1 comprises a rotating electric machine 11 and a torque transmission system 1 for rotating two half-shafts 13 and 14 of a vehicle axle.

[0073] Such a powertrain 10 is, for example, intended for a hybrid vehicle. Thus, the powertrain 10 is, for example, capable of transmitting torque from a rotating electric machine 11 to a rear or front axle of the vehicle, while another powertrain coupled to a different engine, such as an internal combustion engine, generates torque and transmits it between this other engine and half-shafts of the wheels on the other axle of the vehicle. The vehicle can also be fully electric and have one or more powered axles.

[0074] The torque transmission system 1 has a speed reduction function. In order to give the vehicle good speed and torque performance by limiting losses, while allowing the rotating electrical machine 11 to operate in a favorable speed and torque operating range, the torque transmission system 1 is intended to establish a speed ratio between the rotating electrical machine 11 and the wheel half-shafts 13 and 14 of the vehicle.

[0075] For this purpose, the torque transmission system 1 comprises a transmission housing 100 in which are housed a drive shaft 2 having an axis of rotation X, a planetary gear set 3 and a differential 9. The drive shaft 2, the planetary gear set 3 and the differential 9 can be coaxial with the axis of rotation X. Seals 15 can be used to make the transmission housing 100 watertight.

[0076] In the embodiment of [Fig. 1], the rotating electric machine 11 is coaxial with the drive shaft 2 and drives the drive shaft 2 in rotation. The drive shaft 2 may be hollow. A half-shaft of the wheel 13 is coaxial with the drive shaft 2 and passes axially inside the hollow drive shaft 2.

[0077] As illustrated by Figures 2 and 3, the planetary train, also known as the "epicyclic train", comprises a planetary pinion 4, an external toothed ring 5, a plurality of planetary pinions 6 meshing with the planetary pinion 4 and the external toothed ring 5, and a planet carrier 7 on which the plurality of planetary pinions 6 are pivotally mounted.

[0078] In this embodiment, there are three planetary gears 6, which are pivotally mounted by their radially inner edges on axes 701 of the planet carrier 7 via first bearings 702, here needle bearings. For each planetary gear 6, two first bearings 702 can be used, the first two bearings 702 being axially positioned relative to each other via a cylindrical spacer 705. The axes 701 of the planet carrier 7 have conduits 703 configured to carry lubricant from inlets 704 of said conduits 703 to the first bearings 702.

[0079] In another embodiment not shown, the planetary gears can be pivotally mounted by their radially external edges on the planet carrier via first bearings, in particular needle bearings. In this case, the conduits configured to carry lubricant from the inlets of said conduits to the first bearings are arranged in the satellite gears.

[0080] As illustrated in Figures 1 to 4, the differential 9 may comprise a housing 900 containing a gear set 901 configured to distribute the torque supplied by the rotating electric machine 11 to the wheel half-shafts 13 and 14, allowing them to rotate at different speeds. The gear set 901 of the differential 9 may be a worm gear arrangement. This type of differential is commonly known as a "Torsen" differential, advantageously used for its compactness and / or its limited-slip function. The structure of the differential housing 900 may be a single piece or composed of several sub-parts 900 and 904 fixed together, for example, by screws 21. The planet carrier s 7 may be formed from the same material as the differential housing 900, for example, obtained by a casting process.The differential housing 900 and / or the planet carrier 7 can be supported and guided in rotation on the transmission housing 100 via a second bearing 16 and a third bearing 23, the second bearing 16 and the third bearing 23 being ball bearings.

[0081] In the embodiment shown in Figures 2 to 4, the planetary gear 4 is rotationally connected to the drive shaft 2, for example, by a spline. The planetary gear 4 is axially locked against translation, for example, by a retaining ring. The planet carrier 7 is rotationally connected to the differential housing 900. The outer ring gear 5 is fixed to the transmission housing 100, for example, by shrink fitting.

[0082] In the embodiment of figures 2 to 4, the satellite gears 6 are double satellite gears, each comprising a large satellite gear 601 and a small satellite gear 602 having a diameter smaller than that of the large satellite gear 601, the large satellite gear 601 and the small satellite gear 602 being rotationally linked and arranged axially side by side, the large satellite gear 601 being meshed with the planetary gear 4 and the small satellite gear 602 being meshed with the outer toothed ring 5. In a known manner, this planetary gear train configuration is called a "type 2 planetary gear train".

[0083] A lubricant is used to lubricate the components of the torque transmission system 1. The lubricant can be, for example, an oil.

[0084] As illustrated in Figures 2 and 3, the transmission housing 100 comprises a first wall 101 supporting an injection device 18, the injection device 18 having at least one first outlet 181 configured to project a jet of lubricant directly towards at least one of the inlets 704 of the conduits 703 arranged in the axes 701 of the planet carrier 7. The at least one first outlet 181 of the injection device 18 may be axially opposite the inlets 704 of the conduits 703. In this embodiment, the injection device 18 is located under the form of a cylindrical plastic insert fixed by insertion into the first wall 101.

[0085] As illustrated in Figures 2, 3, and 6, a collection device 22 can be fixed to the planet carrier 7, the collection device 22 being configured to collect a portion of the lubricant projected from at least one first outlet 181 of the injection device 18 and to direct the lubricant to the inlets 704 of the conduits 703. The collection device 22 can include at least one reservoir 221 adapted to receive a predetermined quantity of lubricant, the at least one reservoir 221 having in its radially internal portion an opening 222, the opening 222 being positioned radially above at least one first outlet 181 of the injection device 18 and the opening 222 axially covering at least one first outlet 181 of the injection device 18. Figure 3 illustrates the path 20 (symbolized by arrows). lubricant from the injection device 18 to the first bearings 702.

[0086] In the embodiment shown in Figures 4 and 6, the collection device 22 may be composed of several distinct parts, for example, three distinct parts, the number of distinct parts preferably corresponding to the number of planetary gears 6, each distinct part comprising a separate reservoir 221. Each distinct part of the collection device 22 may include a mounting wall 223 adapted to fit into the conduit 703 of a shaft 701 of the planetary carrier 7. In order to prevent the rotation of the collection device 22 relative to the planetary carrier 7, a retaining pin 224 passing through the mounting wall 223 of the collection device 22 and through the shaft 701 may be used, in particular a shouldered cylindrical pin.

[0087] In an embodiment not shown, the collection device can be a single piece and extend circumferentially over an angle of 360°. The collection device can then be fixed to the axes 701 of the satellite carrier 7 via suitable fixing means.

[0088] As illustrated in Figures 2, 3, and 5, the satellite carrier s 7 can be supported by the first wall 101 of the transmission housing 100 via the second bearing 16, with at least one first outlet 181 of the injection device 18 being positioned radially above the second bearing 16. The transmission housing 100 may include an axially projecting cylindrical portion 102. The cylindrical portion 102 may be positioned radially below the opening 222 of at least one reservoir 221 of the collection device 22, and the cylindrical portion 102 may axially cover the opening 222 of at least one reservoir 221 of the collection device 22. The axially projecting cylindrical portion 102 of the transmission housing 100 may include a radially internal surface adapted to support the second bearing 16. The injection device 18 may include at least one second outlet orifice 182 positioned radially below the second bearing 16. The second outlet device 182 may be configured to project a jet of lubricant towards the planetary gear 4.

[0089] As illustrated in Figures 1 and 2, the lubricant projected from at least one first outlet 181 of the injection device 18 can originate from a chamber 19 of the transmission housing 100. The lubricant contained in the chamber 19 can also be used for the lubrication and / or cooling of the rotating electrical machine 11. The lubricant can be pressurized and injected into the chamber 19 by means of a pump (not shown). The transmission housing 100 can include, in a lower portion, a collection tray 17 into which the lubricant flows by gravity after circulating through the torque transmission system 1. The pump can recover the lubricant from the collection tray 17 and then reinject it into the chamber 19.

[0090] It is emphasized that all features, as they are apparent to a person skilled in the art from the present description, drawings and attached claims, even if in practice they have only been described in relation to other specific features, both individually and in any combinations, can 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.

[0091] 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.

[0092] In the claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

Demands

1. Torque transmission system (1) for a vehicle comprising: • a drive shaft (2) having an axis of rotation (X); • a transmission housing (100); and • a planetary gear train (3) comprising a planetary pinion (4), an outer ring gear (5), a plurality of planetary gears (6) meshing with the planetary pinion (4) and the outer ring gear (5), and a planet carrier (7) on which the planetary gears (6) are pivotally mounted via first bearings (702), the planet carrier (7) or the planetary gears (6) having a plurality of conduits (703) configured to carry lubricant from inlets (704) of said conduits (703) to the first bearings (702);characterized in that the transmission housing (100) has a first wall (101) supporting an injection device (18), the injection device (18) having at least one first outlet orifice (181) configured to project a jet of lubricant directly towards at least one of the inlets (704) of the conduits (703).

2. Torque transmission system (1) according to claim 1, wherein at least one first outlet port (181) of the injection device (18) is axially opposite the inlets (704) of the conduits (703).

3. Torque transmission system (1) according to any one of the preceding claims, wherein the lubricant jet is injected through at least one first outlet orifice (181) of the injection device (18) at a pressure between 1 and 20 bar, preferably a pressure between 1.5 and 6 bar.

4. Torque transmission system (1) according to any one of the preceding claims, wherein a collection device (22) is fixed on the planet carrier (7), the collection device (22) being configured to collect a portion of the lubricant projected by at least one first outlet orifice (181) of the injection device (18) and to direct the lubricant to the inlets (704) of the conduits (703).

5. Torque transmission system (1) according to claim 4, wherein the collection device (22) comprises at least one reservoir (221) adapted to receive a determined quantity of lubricant, the at least one reservoir (221) having in its radially internal part an opening (222), the opening (222) being positioned radially above the at least one first outlet orifice (181) of the injection device (18).

6. Torque transmission system (1) according to claim 5, wherein the opening (222) axially covers at least one first outlet orifice (181) of the injection device (18).

7. Torque transmission system (1) according to claim 5 or 6, wherein the collection device (22) is composed of several separate parts, the number of separate parts preferably corresponding to the number of satellite gears (6), each separate part comprising a separate reservoir (221).

8. Torque transmission system (1) according to any one of the preceding claims, wherein the planet carrier (7) is supported by the first wall (101) of the transmission housing (100) via a second bearing (16), at least one first outlet port (181) of the injection device (18) being positioned radially above the second bearing (16).

9. Torque transmission system (1) according to any one of the preceding claims combined with claim 5, wherein the transmission housing (100) has an axially projecting cylindrical portion (102), the cylindrical portion (102) being positioned radially below the opening (222) of at least one reservoir (221) of the collection device (22) and the cylindrical portion (102) axially covering the opening (222) of at least one reservoir (221) of the collection device (22).

10. Torque transmission system (1) according to any one of the preceding claims, wherein the injection device (18) has a plurality of circumferentially distributed first outlet orifices (181), preferably from three to twelve first outlet orifices (181).

11. Torque transmission system (1) according to any one of the preceding claims, wherein: • said torque transmission system (1) further comprises a differential housing (9); • the planetary pinion (4) is rotationally linked to the drive shaft (2); • the planet carrier (7) is rotationally linked to the differential housing (9); • the outer ring gear (5) is fixed to the transmission housing (100); and • the differential housing (900) is supported by the transmission housing (100) via at least one third bearing (23).

12. Powertrain (10) comprising: • a lubricant; • a torque transmission system (1) according to any one of the preceding claims; • a rotating electrical machine (11) configured to rotate the drive shaft (2); • an engine housing (12) housing the rotating electrical machine (11).

13. Powertrain (10) according to claim 12, wherein the lubricant projected by at least one first outlet orifice (181) of the injection device (18) comes from the engine casing (12) or from a chamber (19) provided in the engine casing (12) and / or in the transmission casing (100).

14. Powertrain (10) according to claim 12 or 13, wherein the lubricant is injected and / or withdrawn from the transmission case (100) and / or from the engine case (12) by means of a pump.

15. Powertrain (10) according to any one of claims 12 to 14, wherein the rotating electrical machine (11) is coaxial with the drive shaft (2).

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