Powertrain

Abstract

The invention relates to a powertrain (1) for a vehicle, comprising: − a speed reducer (10) comprising a planetary gear train (3), the planetary gear train (3) including a sun gear (4); – a motor (11) rotating a hollow rotor shaft (1102); − a drive shaft (2) housed entirely or partially radially inside the rotor shaft (1102), the drive shaft (2) including a first rotational connection (200) to the rotor shaft (1102) and a second rotational connection (201) to the sun gear (4), the second rotational connection (201) forming an overhang and being located axially opposite the first connection (200) so as to allow radial movement of the sun gear (4); characterised in that a line (8) capable of carrying a lubricant is arranged radially between the rotor shaft (1102) and the drive shaft (2).

Description

[0001] Description

[0002] Title of the invention: Powertrain Technical field

[0003] [1] The present invention relates to the field of powertrains for motor vehicles, particularly for hybrid or electric vehicles. More specifically, the invention relates to a powertrain connected to a wheel via a speed reducer using a planetary gear set linked to the rotor part of the motor.

[0004] Technological background

[0005] [2] Document FR2727655A1 describes a powertrain in which a speed reducer transmits the torque delivered by a motor to the wheels of a vehicle via a planetary gear train and a differential arranged coaxially with the motor. Such a coaxial arrangement improves radial compactness, particularly compared to speed reducers using parallel gear trains.

[0006] [3] As is known, a planetary gear train inherently exhibits a statically indeterminate structure when misalignment of its components occurs, for example, due to manufacturing defects or misalignment of said components. This static indeterminacy can then cause wear, breakage, or jamming of the meshing of these components. To resolve this problem, document FR2727655A1 proposes a powertrain architecture in which the planetary gear of the planetary gear train is driven in rotation by the engine via a flexible shaft capable of transverse deflection, thus absorbing the misalignment of the planetary gear train components.

[0007] [4] However, such a powertrain architecture presents several technical problems, primarily the issue of ensuring adequate and consistent lubrication of the various internal components of the gearbox and engine. Indeed, the requirements for increased compactness necessitate cramming a large number of internal powertrain components into a limited space. Consequently, some areas are difficult to access, making it difficult to deliver the necessary amount of lubricant for their proper operation. As a result, certain internal components critical to service life, such as the planetary gear teeth and the engine rotor, are insufficiently lubricated.

[0008] Summary

[0009] [5] In what 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.

[0010] [6] An idea underlying the invention is a powertrain that makes it possible to solve one or more technical problems of the prior art, for example the aforementioned problems.

[0011] [7] The invention relates to a vehicle powertrain comprising:

[0012] - a speed reducer housed in a transmission casing and comprising a planetary gear train, the planetary gear train having a planetary pinion; - a motor housed in a motor casing and comprising a rotor, the rotor driving a hollow rotor shaft in rotation around an axis of rotation; - a drive shaft housed wholly or partly radially inside the rotor shaft, the drive shaft having a first rotational link with the rotor shaft and a second rotational link with the planetary pinion, the second rotational link being arranged in axial cantilever opposite the first link in order to allow radial movement of the planetary pinion;

[0013] a conduit suitable for conducting a lubricant being arranged radially between the rotor shaft and the drive shaft.

[0014] [8] Thus, the invention consists of advantageously using the radial space resulting from the cantilevered arrangement of the drive shaft inside the rotor shaft to create an efficient and compact lubricant channel for lubricating and / or cooling the motor rotor and the various components of the speed reducer. [9] Furthermore, the presence of lubricant inside the channel dampens the radial accelerations of the planetary gear due to the flexibility of the drive shaft that carries it. Shocks, particularly between the teeth of the planetary gear train components, are thereby reduced, and consequently, the mechanical damage and noise produced by these shocks are significantly attenuated.

[0015]

[0010] For the purposes of this application:

[0016] - "axial" means "parallel to the axis of rotation";

[0017] - "radial" means "along an axis belonging to a plane orthogonal to the axis of rotation and intersecting this axis of rotation";

[0018] - "circumferential" means "around the axis of rotation";

[0019] - "rotationally linked" means "assembled so that they do not rotate relative to each other." In other words, it is a rotationally fixed joint, possibly with very little play such as spline play;

[0020] - two parts are said to be "fixed" when they are permanently immobilized relative to each other, this immobilization being able to result from the fixing of the first part on the second part directly or through one or more intermediate parts.

[0021]

[0011] According to a further feature of the invention, the conduit comprises an inlet orifice and a first outlet orifice, the inlet orifice and the first outlet orifice being positioned axially on either side of the rotor.

[0022]

[0012] This last characteristic defines a path of the lubricant which goes axially from one side to the other of the motor, thus allowing an extended and prolonged contact of the lubricant with the rotor shaft and therefore improved cooling of the rotor.

[0023]

[0013] According to an additional feature of the invention, the first outlet orifice opens into the transmission housing.

[0024]

[0014] Thus, a single lubricant can be used both for cooling the rotor and for lubricating components of the speed reducer.

[0015] According to a further feature of the invention, the conduit has a second outlet port, the second outlet port opening into the transmission housing or into the motor housing.

[0025]

[0016] In one embodiment, the second lubricant outlet orifice can be adapted to open into an area of ​​the transmission housing allowing the lubrication of components of the speed reducer which are difficult to access and hard to reach by the lubricant exiting through the first outlet orifice.

[0026]

[0017] In another embodiment, the second lubricant outlet port can be adapted to open into the engine casing for the cooling of other engine components, such as stator components and / or electronic systems associated with the power supply and control of the engine.

[0027]

[0018] According to an additional feature of the invention, the inlet port is positioned axially between the rotor and the first rotating link.

[0028]

[0019] According to an additional feature of the invention, the first outlet port is positioned axially between the rotor and the second rotating link.

[0029]

[0020] According to an additional feature of the invention, the second outlet port is positioned axially between the rotor and the second rotating link.

[0030]

[0021] According to a further feature of the invention, the first outlet port is an opening port at the distal end of the rotor shaft.

[0031]

[0022] According to an additional feature of the invention, the first outlet orifice is an opening orifice in the immediate vicinity of the planetary gear.

[0032]

[0023] According to a further feature of the invention, the inlet port and the second outlet port are radially oriented and arranged in the rotor shaft.

[0033]

[0024] According to a further feature of the invention, the powertrain comprises a plurality of inlet ports and / or a plurality of first outlet ports and / or a plurality of second outlet ports.

[0025] According to a further feature of the invention, the inlet ports and / or the first outlet ports and / or the second outlet ports are distributed circumferentially around the axis of rotation.

[0034]

[0026] These last eight features, taken alone or in combination, define a conduit structure between the rotor shaft and the drive shaft allowing improved lubricant flow for cooling and lubrication of the components of the speed reducer and / or the motor.

[0035]

[0027] According to a further feature of the invention, a first sealing means, in particular an O-ring, is provided between the rotor shaft and the drive shaft in order to make the conduit sealed.

[0036]

[0028] Thus, the first sealing means prevents lubricant leakage into the conduit, particularly at the first rotating joint. This first sealing means is especially necessary if the first rotating joint has some radial or circumferential play, such as a splined joint.

[0037]

[0029] According to a further feature of the invention, at least one groove is formed inside the conduit on the outer surface of the drive shaft and / or on the inner surface of the rotor shaft.

[0038]

[0030] The purpose of at least one groove is to increase the heat exchange surface between the lubricant circulating in the conduit and the drive shaft and / or the rotor shaft, thereby improving the efficiency of rotor cooling.

[0039]

[0031] According to a further feature of the invention, the rotor includes a circulation circuit suitable for receiving the lubricant, said circulation circuit cooperating with the conduit so that the lubricant passes from a first portion of the conduit to the circulation circuit, and then from the circulation circuit to a second portion of the conduit.

[0040]

[0032] The circulation circuit allows the lubricant to circulate inside the rotor and thus further improve its cooling. The length of the circulation circuit, and therefore its cooling capacity, can be improved by modifying the shape of the circulation circuit.

[0033] According to a further feature of the invention, the circulation circuit, in a cross-sectional view in a plane passing through the axis of rotation, has a sinuous path inside the rotor.

[0041]

[0034] The sinuous path gives the conduit a trajectory with several turns and changes of direction, allowing it to reach the different parts of the rotor and increasing the distance traveled by the lubricant within the rotor. The sinuous path can, in particular, take the general shape of the letter T, M, or U in a cross-sectional view in a plane passing through the axis of rotation. The sinuous path can also extend circumferentially in a sinuous manner.

[0042]

[0035] According to an additional feature of the invention, a second sealing means, in particular an O-ring, separates the first portion of the conduit from the second portion of the conduit.

[0043]

[0036] The second sealing means prevents direct communication between the first portion of the conduit and the second portion of the conduit, thus forcing the lubricant to travel through the circulation circuit to cool the inside of the rotor.

[0044]

[0037] According to a further feature of the invention, the powertrain includes a lubricant, the lubricant being an oil, in particular a dielectric oil.

[0045]

[0038] Thus a single lubricant is used to cool, lubricate and electrically insulate the different components of the motor and the speed reducer.

[0046]

[0039] According to a further feature of the invention, the powertrain includes a pump capable of drawing lubricant from the transmission case and / or from the engine case and injecting said lubricant into the conduit.

[0047]

[0040] The pump allows sufficient lubricant pressurization so that the lubricant can move easily inside the conduit, in the circulation circuit and in the cooled engine components.

[0041] The use of a pump also allows so-called "active" lubrication of the speed reducer which ensures the distribution of a localized and limited quantity of lubricant just necessary within and thus reduces the efficiency losses due to the bubbling of the components in the lubricant, unlike so-called "passive" lubrication without a pump which uses a gravity lubrication principle requiring a larger quantity of lubricant.

[0048]

[0042] According to an additional feature of the invention:

[0049] - the rotor shaft is supported by a fixed frame, in particular the motor housing, via a first bearing and a second bearing, the first bearing being positioned axially further from the planetary pinion than the second bearing; and - the first rotating link is positioned axially further from the planetary pinion than the second bearing, in particular the first rotating link is positioned axially further from the planetary pinion than the first bearing.

[0050]

[0043] This relative positioning of the first and second links with respect to the bearings of the rotor shaft advantageously leads to a powertrain structure where the flexing length of the drive shaft is increased, thus making it easy to give it the desired flexibility.

[0051]

[0044] According to a further feature of the invention, the first rotating link and the second rotating link are respectively positioned on a first end and a second end axially opposite to the drive shaft.

[0052]

[0045] According to a further feature of the invention, the first bearing and / or the second bearing are needle bearings or ball bearings or roller bearings or plain bearings.

[0053]

[0046] According to a further feature of the invention, the drive shaft has a flexible length measured axially between the first rotating joint and the second rotating joint and an outside diameter, the ratio between the flexible length and the outside diameter being between three and seven, preferably between four and six.

[0047] Thanks to this latter feature, it is possible to give the drive shaft the dimensions adapted to obtain the desired flexibility while ensuring sufficient mechanical resistance for the transmission of the torque delivered by the motor.

[0054]

[0048] By measured bending length, we mean here the minimum measurable axial length between the first rotating joint and the second rotating joint, excluding any portion of the first rotating joint and any portion of the second rotating joint.

[0055]

[0049] By outside diameter, we mean here the average outside diameter of the entire measured flexing length.

[0056]

[0050] According to one aspect of the invention, the first rotational link is a splined link.

[0057]

[0051] This splined connection has the advantage of ensuring the transmission of torque while allowing, thanks to its low internal backlash between teeth, a possibility of a low angle of the drive shaft relative to the axis of rotation, and thus providing an additional free radial displacement of the planetary gear positioned axially opposite the drive shaft.

[0058]

[0052] According to another aspect of the invention, the first rotational link is a welded link or a press-fitted link.

[0059]

[0053] According to one aspect of the invention, the second rotating link is a monobloc link, the planetary pinion and the drive shaft being made together from the same material.

[0060]

[0054] According to another aspect of the invention, the second rotational link is a splined link or a welded link or a press-fit link.

[0061]

[0055] According to a further feature of the invention, an elastic device is disposed between the rotor shaft and the drive shaft.

[0062]

[0056] The use of such an elastic device allows the radial movement of the planetary gear to be free while damping the radial accelerations related to the flexibility of the drive shaft. Shocks, particularly between the teeth of the planetary gear train components, are thus reduced, and consequently, the mechanical damage and noise produced by these shocks are significantly attenuated.

[0063]

[0057] According to a further feature of the invention, the elastic device is composed in whole or in part of a damping material such as elastomer, felt or plastic.

[0064]

[0058] According to a further feature of the invention, the elastic device is formed by a washer having radially oriented undulations or radially oriented blades.

[0065]

[0059] These last two characteristics make it possible to determine the shape and / or material suitable for obtaining the desired elastic, viscoelastic and damping properties for the elastic device.

[0066]

[0060] According to a further feature of the invention, the elastic device is configured to exert friction against the hollow shaft and / or against the drive shaft during the radial movement of the planetary gear.

[0067]

[0061] Thus, the friction generated causes energy dissipation allowing additional damping of the radial displacement of the planetary gear.

[0068]

[0062] According to an additional feature of the invention, the elastic device is mounted radially tightly between the hollow shaft and the drive shaft.

[0069]

[0063] Thanks to this latter feature, radial play is completely eliminated between the elastic device and the hollow shaft on the one hand, and between the elastic device and the drive shaft on the other. The elastic device therefore performs its damping function even for small values ​​of radial displacement of the drive shaft.

[0070]

[0064] According to a further feature of the invention, the elastic device is disposed inside the conduit, the elastic device and / or the drive shaft and / or the rotor shaft having openings suitable for the lubricant to pass axially through.

[0071]

[0065] Thus, the presence of the elastic device in the conduit does not impede the circulation of the lubricant in said conduit.

[0066] According to a further feature of the invention:

[0072] - the planetary train further includes an external toothed ring fixed to the transmission housing, at least one satellite pinion meshing with the planetary pinion and the external toothed ring, and a planet carrier on which at least one satellite pinion is pivotally mounted;

[0073] - the speed reducer further includes a differential, the differential having a housing fixed to the planet carrier, the differential being configured to drive two half-shafts in rotation; and

[0074] - the drive shaft is hollow and radially surrounds one of the two wheel half-shafts.

[0075]

[0067] The overall architecture thus defined makes it possible to improve the radial and axial compactness of the powertrain according to the invention, while having a speed reducer with a significant reduction ratio.

[0076]

[0068] According to an additional feature of the invention, the motor is an electric motor.

[0077]

[0069] According to an additional feature of the invention, the motor is an axial flux electric motor.

[0078]

[0070] The invention is advantageously associated with an axial flux motor because the rotor shaft is structurally shorter, and therefore less flexible, for this type of motor than for radial flux motors.

[0079] Brief description of the figures

[0080]

[0071] Figure 1 is a broken cross-sectional view of a first embodiment of a powertrain according to the invention.

[0081]

[0072] Figure 2 is an enlarged view of a part of Figure 1.

[0082]

[0073] Figure 3 is an enlarged view of a part of Figure 1.

[0083]

[0074] Figure 4 is an isometric view of a drive shaft of a powertrain according to the invention.

[0084]

[0075] Figure 5 is a partial broken cross-sectional view of a second embodiment of a powertrain according to the invention.

[0076] Figure 6 is an isometric view of a first embodiment of the elastic device of a powertrain according to the invention.

[0085]

[0077] Figure 7 is an isometric view of a second embodiment of the elastic device of a powertrain according to the invention.

[0086] Description of the implementation methods

[0087]

[0078] 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.

[0088]

[0079] Figure 1 illustrates a powertrain 1 according to an embodiment of the invention. The powertrain 1 comprises a motor 11 and a speed reducer 10 intended to drive in rotation two wheel half-shafts 13 and 14 of a vehicle axle.

[0089]

[0080] Such a powertrain 1 is for example intended for a hybrid vehicle.

[0090] Thus, powertrain 1, for example, is capable of transmitting torque from motor 11, motor 11 being an electric motor, to a rear or front axle of the vehicle, while another powertrain coupled to another motor, such as an internal combustion engine, generates torque and transmits it between this other motor and the 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.

[0091]

[0081] The motor 11 can be an electric motor comprising a stator 1100, a rotor 1101, and a hollow rotor shaft 1102. The rotor shaft 1102 is rotationally linked to the rotor 1101 and rotates about an axis of rotation X. The motor 11 can be housed in a motor casing 12.

[0092]

[0082] The speed reducer 10 is intended to establish a speed ratio between the motor 11 and the wheel half-shafts 13 and 14 of the vehicle. Thus, the speed reducer 10 enables the vehicle to achieve good speed and torque performance by limiting losses, while allowing the motor 11 to operate within a favorable speed and torque range.

[0093]

[0083] For this purpose, the speed reducer 10 includes a transmission housing 100 in which are housed a drive shaft 2 having an axis of rotation X, a planetary gear train 3 and a differential 9. The drive shaft 2, the planetary gear train 3 and the differential 9 can be coaxial with the axis of rotation X.

[0094]

[0084] In the embodiment of Figure 1, the motor 11 is coaxial with the drive shaft 2 and is configured to rotate the drive shaft 2. The drive shaft 2 may be hollow. A half-shaft of the wheel 13 is coaxial with the drive shaft 2 and may pass axially inside the hollow drive shaft 2.

[0095]

[0085] As illustrated in Figure 2, the planetary gear train, also commonly referred to as an "epicyclic gear train," comprises a planetary gear 4, an external ring gear 5, a plurality of planetary gears 6 meshing with the planetary gear 4 and the external ring gear 5, and a planet carrier 7 having shafts 701 on which the plurality of planetary gears 6 are pivotally mounted. The external ring gear 5 can be fixed to the transmission housing 100, for example by shrink fitting.The satellite gears 6 can be 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 ring gear 5. This planetary gear train configuration is known to be called a "type 2 planetary gear train".

[0096]

[0086] As illustrated in Figure 2, the differential 9 may include a housing 900 containing a set of gears 901 configured to distribute the torque supplied by the motor 11 to the wheel half-shafts 13 and 14, allowing them to rotate at different speeds. The planet carrier 7 may be made of 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 may be supported and guided in rotation on the transmission housing 100 by means of ball bearings (not shown).

[0097]

[0087] As illustrated by Figure 1, the drive shaft 2 is housed radially inside the rotor shaft 1102, the drive shaft 2 having a first rotational link 200 with the rotor shaft 1102 and a second rotational link 201 with the planetary pinion 4, the second rotational link 201 being arranged in axial cantilever opposite the first link 200 in order to allow radial movement of the planetary pinion 4.

[0098]

[0088] In this embodiment, the first rotating joint 200 is a splined joint. The male part of the splines 200 is formed on the drive shaft 2 and cooperates with the female part of the splines 200 formed on the rotor shaft 1102. The second rotating joint 201 is a single-piece joint, the planetary gear 4 and the drive shaft 2 being formed from a single piece of material.

[0099]

[0089] The rotor shaft 1102 can be supported by the motor housing 12 via a first bearing 15, here a ball bearing, and a second bearing 16, here a roller bearing. The first bearing 15 can be positioned axially further from the planetary gear 4 than the second bearing 16. The first rotating link 200 can be positioned axially further from the planetary gear 4 than the second bearing 16. The first rotating link 200 is also positioned axially further from the planetary gear 4 than the first bearing 15.

[0100]

[0090] As illustrated by Figure 3, a conduit 8 suitable for conducting a lubricant is arranged radially between the rotor shaft 1102 and the drive shaft 2. A first sealing means 18, here an O-ring inserted radially in a groove of the drive shaft 2, can be arranged between the rotor shaft 1102 and the drive shaft 2 in order to make the conduit 8 sealed.

[0101]

[0091] The conduit 8 may have a plurality of inlet ports 1103 through which a lubricant enters. The inlet ports may be distributed circumferentially around the axis of rotation X. The plurality of inlet ports 1103 may be positioned axially between the rotor 1101 and the first rotating link 200. The inlet ports 1103 may be oriented radially and arranged in the rotor shaft 1102.

[0102]

[0092] The conduit 8 may include a first outlet orifice 1104. The first outlet orifice 1104 and the plurality of inlet orifices 1103 may be positioned axially on either side of the rotor 1101. The first outlet orifice 1104 may be positioned axially between the rotor 1101 and the second rotating link 201. The first outlet orifice 1104 may be an opening into the transmission housing 100 at the distal end of the rotor shaft 1102 and in the immediate vicinity of the planetary gear 4.

[0103]

[0093] The conduit 8 may include a plurality of second outlet ports 1105.

[0104] The second output ports can be distributed circumferentially around the axis of rotation X. The second output ports 1105 can be positioned axially between the rotor 1101 and the second rotating link 201. The second output ports 1105 can open into the transmission housing 100, for example to supply lubricant to the components of the speed reducer 10. The second output ports 1105 can be oriented radially and arranged in the rotor shaft 1102.

[0105]

[0094] The rotor 1101 may include a circulation circuit 800 adapted to receive the lubricant, said circulation circuit 800 cooperating with the conduit 8 so that the lubricant flows from a first portion 801 of the conduit 8 to the circulation circuit 800, and then from the circulation circuit 800 to a second portion 802 of the conduit 8. A second sealing means 19, here an O-ring, separates the first portion 801 from the second portion 802 in order to force the lubricant to pass through the circulation circuit 800. The circulation circuit 800 may have a convoluted path, here in the shape of the letter T, inside the rotor 1101.

[0106]

[0095] The powertrain 1 may further include a pump [not shown] suitable for drawing lubricant from the transmission housing 100 and / or from the engine housing 12 and for injecting said lubricant into the conduit 8. The support 17 may be fixed to the engine housing 12 and may be configured to make the pump cooperate with the inlet ports 1103 of the conduit 8.

[0107]

[0096] As illustrated in figure 4, a groove 202 extending along a helix rotating around the axis of rotation X can be formed inside the conduit 8 on the outer surface of the drive shaft 2. The drive shaft 2 can have a bending length L measured axially between the first rotating link 200 and the second rotating link 201 and an outside diameter D, the ratio between the bending length L and the outside diameter D being between four and six.

[0108]

[0097] Figure 5 shows a second embodiment of the invention in which an elastic device 20 can be disposed in the conduit 8 between the rotor shaft 1102 and the drive shaft 2 so as to dampen the radial displacement of the planetary gear 4. The elastic device 20 can be housed in a recess, here an annular groove, formed radially in the rotor shaft 1102. The elastic device 20 can be radially press-fitted between the rotor shaft 1102 and the drive shaft 2. The elastic device 20 can be axially positioned between the planetary gear 4 and the second bearing 16.

[0109]

[0098] As illustrated in Figure 6, the elastic device 20 can be in the form of an annular piece made of a damping material, such as an elastomer or plastic. Openings 2001 can be provided to allow axial passage of the lubricant from the conduit 8.

[0110]

[0099] As illustrated in Figure 7, the elastic device 20 can be in the form of an elastic washer, having radially oriented and circumferentially arranged corrugations 2003. This washer can, for example, be a steel washer pre-stressed in the annular groove 1103. Openings 2002 located in the radial space above or below the corrugations 2003 can allow the axial passage of the lubricant from the conduit 8.

[0111]

[0100] In another embodiment not shown, in particular in the case where the elastic device does not have openings allowing axial passage of the lubricant, notches, such as axial grooves, can be provided in the drive shaft 2 and / or in the rotor shaft 1102 to ensure the passage of the lubricant in the conduit 8.

[0112]

[0101] 11 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.

[0113]

[0102] 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.

[0114]

[0103] In the claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

Demands 1. Powertrain (1) for vehicle comprising: - a speed reducer (10) housed in a transmission casing (100) and comprising a planetary gear train (3), the planetary gear train (3) comprising a planetary pinion (4); - a motor (11) housed in a motor casing (12) and comprising a rotor (1101), the rotor (1101) driving in rotation around an axis of rotation (X) a hollow rotor shaft (1102); - a drive shaft (2) housed wholly or partly radially inside the rotor shaft (1102), the drive shaft (2) having a first rotational link (200) with the rotor shaft (1102) and a second rotational link (201) with the planetary pinion (4), the second rotational link (201) being arranged in axial cantilever opposite the first link (200) in order to allow radial movement of the planetary pinion (4); characterized in that a conduit (8) suitable for conducting a lubricant is arranged radially between the rotor shaft (1102) and the drive shaft (2).

2. Powertrain unit (1) according to claim 1, in which the conduit (8) has an inlet port (1103) and a first outlet port (1104), the inlet port (1103) and the first outlet port (1104) being positioned axially on either side of the rotor (1101).

3. Powertrain (1) according to claim 2, wherein the first outlet port (1104) opens into the transmission housing (100).

4. Powertrain (1) according to any one of claims 1 to 3, wherein the conduit (8) has a second outlet port (1105), the second outlet port (1105) opening into the transmission housing (100) or into the engine housing (12).

5. Powertrain (1) according to any one of the preceding claims, wherein a first sealing means (18), in particular an O-ring, is arranged between the rotor shaft (1102) and the drive shaft (2) in order to make the conduit (8) sealed.

6. Powertrain (1) according to any one of the preceding claims, wherein at least one groove (202) is formed inside the conduit (8) on the outer surface of the drive shaft (2) and / or on the inner surface of the rotor shaft (1101).

7. Powertrain (1) according to claim 6, wherein at least one groove (202) is a groove extending along a helix rotating about the axis of rotation (X) or a groove extending parallel to the axis of rotation (X).

8. Powertrain (1) according to any one of the preceding claims, wherein the rotor (1101) comprises a circulation circuit (800) adapted to receive the lubricant, said circulation circuit (800) cooperating with the conduit (8) such that the lubricant flows from a first portion (801) of the conduit (8) to the circulation circuit (800), and then from the circulation circuit (800) to a second portion (802) of the conduit (8).

9. Powertrain (1) according to claim 8, wherein a second sealing means (19), in particular an O-ring, separates the first portion (801) of the conduit (8) from the second portion (802) of the conduit (8).

10. Powertrain (1) according to claim 8 or 9, wherein the circulation circuit (800) has, in a sectional view in a plane passing through the axis of rotation (X), a sinuous path inside the rotor (1101).

11. Powertrain (1) according to any one of the preceding claims, wherein: - the planetary train (3) further comprises an external toothed ring (5) fixed to the transmission housing (100), at least one satellite pinion (6) meshing with the planetary pinion (4) and the external toothed ring (5), and a planet carrier (7) on which at least one satellite pinion (6) is pivotally mounted; - the speed reducer (10) further comprises a differential (9), the differential (9) having a housing (900) fixed to the planet carrier (7), the differential (9) being configured to drive two half-shafts (13,14) in rotation; and - the drive shaft (2) is hollow and radially surrounds one of the two wheel half-shafts (13,14).

12. Powertrain (1) according to any one of the preceding claims, wherein an elastic device (20) is disposed between the rotor shaft (1102) and the drive shaft (2).

13. Powertrain (1) according to claim 12, wherein the elastic device (20) is disposed inside the conduit (8), the elastic device (20) and / or the drive shaft (2) and / or the rotor shaft (1102) having openings (2001, 2002) suitable for axial passage of the lubricant.

14. Powertrain (1) according to any one of the preceding claims, wherein the powertrain (1) comprises a pump capable of drawing lubricant from the transmission case (100) and / or from the engine case (12) and of injecting said lubricant into the conduit (8).

15. Powertrain (1) according to any one of the preceding claims, wherein the powertrain (1) comprises a lubricant, the lubricant being an oil, in particular a dielectric oil.

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