Transmission shaft for a transmission system for an electric or hybrid vehicle

Abstract

The invention relates to a transmission shaft (10) for a transmission system of an electric or hybrid vehicle, comprising: - a body (13) having a main axis of revolution (X), which body has an outer surface (14), a first end wall (11) and a second end wall (12) substantially perpendicular to the main axis of revolution (X); - a hole (20) capable of receiving a lubricating fluid, which hole is formed from the first end wall (11) and extends inside the body (13), the hole comprising an offset portion (25) having a shape of revolution about a second secondary axis of revolution (X2) offset angularly and / or radially with respect to the main axis of revolution (X), the offset portion (25) not opening into the outer surface (14); - a first duct (21) and a second duct (22) causing the offset portion (25) of the hole to communicate towards the outside of the body through the outer surface (14).

Description

DESCRIPTION TITLE: DRIVE SHAFT FOR TRANSMISSION SYSTEM FOR ELECTRIC OR HYBRID VEHICLES TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a driveshaft for an electric or hybrid vehicle transmission system. This transmission system includes, in particular, an electric motor providing torque and at least one series of gear trains intended to be connected to the vehicle's wheels. When the vehicle also includes an internal combustion engine coupled to the electric motor, the vehicle is said to be "hybrid" because the vehicle's propulsion can be achieved either purely electrically, purely thermally, or in a hybrid manner by using both types of energy simultaneously.

[0002] In the case of a purely electric vehicle, meaning one without an internal combustion engine, electricity can be supplied by a battery or by means of a fuel cell using hydrogen as a reducing fuel. The electric vehicle can be a passenger car or an industrial vehicle, such as a truck, bus, or tractor. PREVIOUS STATE OF THE ART

[0003] The transmission system typically comprises a housing, drive shafts equipped with gears supported by the housing via guide bearings. These guide bearings require constant lubrication by a lubricating fluid circulating within the transmission system.

[0004] For example, such a transmission system is known from patent application DE102015222892A1. In this patent application, the transmission system is a gearbox comprising a first casing defining a first internal volume containing lubricating fluid, a second casing defining a second internal volume containing lubricating fluid, and a transmission shaft passing through both casings. The transmission shaft includes a groove at each of these ends, the first groove being housed in the first casing and the second groove being housed in the second casing.

[0005] The drive shaft includes a bore that passes completely through it, and inside this bore is a helical structure. This helical structure, located within the bore, transports lubricating fluid along the shaft's longitudinal axis from the first housing to the second housing, primarily due to the shaft's rotation. The fluid transport is achieved by the centrifugal force acting on the lubricating fluid.

[0006] The helical structure is either an added component in the shape of a worm gear or a helical groove machined into the inner bore of the drive shaft. In the case of the added component, a specific assembly operation is required. In the case of the helical groove, a costly machining operation is necessary, requiring significant machining time and thus limiting production capacity.

[0007] 11 There is a need to improve the transport of lubricating fluid within a drive shaft of a transmission system when it is desired to efficiently convey the lubricating fluid from one end face to another end when the transmission system lacks a hydraulic pump. DESCRIPTION OF THE INVENTION

[0008] The invention aims in particular to improve the flow of the lubricating fluid within the transmission shaft included in the known transmission system.

[0009] To this end, the invention relates to a drive shaft for an electric or hybrid vehicle transmission system, comprising: - a body having a principal axis of revolution X which has an external surface, a first end wall and a second end wall substantially perpendicular to the principal axis of revolution X; - a hole suitable for receiving a lubricating fluid, formed from the first end wall and extending into the body, the hole comprising an offset portion having a shape of revolution about a secondary axis of revolution X2 offset angularly and / or radially with respect to the main axis of revolution X, the offset portion not opening into the external surface; - a first conduit connecting the off-center portion of the hole to the outside of the body through the external surface; - at least one second conduit, distinct from the first conduit, connecting the offset portion of the hole to the outside of the body through the external surface, the first conduit extending radially along a first axis Y1 and the second conduit extending radially along a second axis Y2 are offset axially and angularly with respect to the main axis of revolution X.

[0010] This drive shaft has the advantage, thanks to the angular offset of the first pipe relative to the second pipe, of adjusting the output flow of the lubricating fluid at the ends of each pipe according to the needs of the transmission system, the main objective being to have a non-zero output flow at the end of the second pipe.

[0011] According to one embodiment of the invention, the first pipe is arranged axially between the first end wall and the second pipe, and in projection onto a first geometric plane perpendicular to the principal axis of revolution X, a first value of angle al is measured between the first axis Y1 of the first pipe and a first eccentricity vector, in projection onto a second geometric plane perpendicular to the principal axis of revolution X, a second value of angle a2 is measured between the second axis Y2 of the second pipe and a second eccentricity vector, the first eccentricity vector starting from the point of intersection of the principal axis of revolution X with the first geometric plane to join the point of intersection of the secondary axis of revolution X2 with said first geometric plane,the second eccentricity vector starting from the point of intersection of the principal axis of revolution X with the second geometric plane to reach the point of intersection of the secondary axis of revolution, X2 with said second geometric plane, the first angle value al is greater than the second angle value a2, the first and second angle values ​​being less than or equal to 180°.

[0012] This drive shaft has the advantage, thanks to the angular offset of the first pipe with the second pipe, of having a different output flow of lubricating fluid between the first pipe and the second pipe, the output flow at the end of the second pipe being non-zero.

[0013] Advantageously, the first pipe can be arranged axially between the first end wall and the second pipe, the connection orifice of the first pipe with the offset portion is located closer to the main axis of revolution X than the connection orifice of the second pipe with the offset portion.

[0014] This transmission shaft has the advantage, thanks to the proximity of the connection orifice of the first pipe with the offset portion, of having a different output flow of lubricating fluid between the first pipe and the second pipe, the output flow at the end of the second pipe being non-zero.

[0015] Preferably, the hole can be a through hole that passes completely through the body from the first end wall to carry the lubricating fluid to the second end wall. In this case, the lubricating fluid outlet flow rate is adjusted between the first pipe, the second pipe, and the fluid outlet at the second end wall, with the outlet flow rate at the second end wall being non-zero.

[0016] Advantageously, the hole may include a lubrication fluid inlet portion concentric to the principal axis of revolution X and the offset portion communicates into the inlet portion.

[0017] Preferably, the drive shaft may include a third conduit connecting the offset portion of the hole to the outside of the body through the external surface, the third conduit being axially interposed between the first conduit and the second conduit.

[0018] Preferably, the drive shaft may include a backflow prevention device, the device being interposed between the input portion and the offset portion. This prevents backflow of lubricating fluid when the drive shaft rotates at low speeds or when the electric or hybrid vehicle is significantly inclined relative to a reference operating position.

[0019] Advantageously, the backflow prevention device may include a cylindrical bore with a diameter greater than the bore diameter of the inlet portion.

[0020] Preferably, the offset portion may include a conical shape flaring out towards the second end wall. The flaring may form a backflow prevention device.

[0021] Advantageously, the transmission shaft may include an unbalancing device, the unbalancing device being for example a removal of material made on the body in opposition to the misalignment of the secondary axis of revolution X2.

[0022] According to one embodiment of the invention, the secondary axis of revolution X2 is intersecting the main axis of revolution X, the secondary axis of revolution X2 is then angularly offset with respect to the main axis of revolution X. The angle of inclination of the secondary axis of revolution X2 with respect to the main axis of revolution X is between 2° and 10°.

[0023] According to one embodiment of the invention, the secondary axis of revolution X2 is parallel and distant from the main axis of revolution X, the secondary axis of revolution X2 is then radially offset with respect to the main axis of revolution X. The eccentricity of the secondary axis of revolution X2 with respect to the main axis of revolution X is between 2 and 10 mm.

[0024] According to another embodiment of the invention, the secondary axis of revolution X2 is not parallel and does not intersect the primary axis of revolution X; the secondary axis of revolution X2 is then angularly and radially offset with respect to the primary axis of revolution X. The angle of inclination of the axis the secondary axis of revolution X2 relative to the main axis of revolution X is between 2° and 10° and the eccentricity of the secondary axis of revolution X2 relative to the main axis of revolution X is between 2 and 10 mm.

[0025] The transmission shaft according to the invention may have one or more of the characteristics described below, either combined or taken independently of each other: - the first pipe and the second pipe are perpendicular to the main axis of revolution X; - the first pipe and the second pipe are perpendicular to the secondary axis of revolution X2; - in projection onto the second geometric plane perpendicular to the principal axis of revolution X, the angular position of the second pipe is aligned with respect to the direction of the eccentricity of the secondary axis of revolution X2, so that the second angle value a2 of the angular position of the second pipe with respect to the second eccentricity vector is equal to 0°; - at the level of the first end wall, the main axis of revolution X is inscribed in the bore diameter of the hole; - the body is partially cylindrical, the external surface may include for example splines, gear teeth, a groove, a cylindrical bearing centering surface; - the transmission shaft includes raw machining surfaces and machined surfaces suitable for contacting a guide bearing and / or splined surfaces suitable for contacting a pinion; - the transmission shaft has one or more gears, these can be fixed in rotation with the transmission shaft or rotate freely around the transmission shaft; - the first end wall and a second end wall are distinct from the external surface.

[0026] All these characteristics have the effect of distinguishing the output flow rate of lubricating fluid between the first pipe and the second pipe.

[0027] The invention also relates, according to another aspect, to a transmission system for an electric or hybrid vehicle comprising: - a crankcase; - a transmission shaft incorporating all or part of the characteristics mentioned above, which is movable in rotation relative to the casing around its main axis of revolution X; - a guide bearing supporting the transmission shaft relative to the casing which includes bearing elements, the guide bearing being inserted into a cylindrical housing provided in the casing; - a lubricating fluid diffuser inserted in the cylindrical housing of the crankcase; in which the lubricating fluid diffuser comprises a diffusion nozzle inserted in the hole of the transmission shaft at the level of the first end wall.

[0028] Preferably, the diffusion nozzle may include an outside diameter that tangents without friction to the bore diameter of the hole.

[0029] This improves the transport of lubricating fluid within the transmission system's drive shaft. The lubricating fluid is efficiently conveyed from one end face to the other, even if the transmission system lacks a hydraulic pump.

[0030] The invention also relates, according to another aspect, to an electrical machine for a transmission system comprising: - a stator; - a rotating rotor that moves around a machine axis comprising a hollow torque output shaft, the rotor being housed inside the stator; and - a transmission shaft incorporating all or part of the characteristics mentioned above, fixed in rotation to the hollow torque output shaft via a splined connection.

[0031] Preferably, the hollow rotor torque output shaft includes a central orifice that opens into the hole in the transmission shaft.

[0032] The invention also relates to a motorized vehicle, for example a hybrid or electric motor vehicle comprising a transmission system as described above. The motorized vehicle could be an industrial vehicle. BRIEF DESCRIPTION OF THE FIGURES

[0033] Other features and advantages of the invention will become apparent from the following description, with reference to the attached figures. [Fig. 1] Figure 1 is a simplified cross-sectional view of a transmission system for an electric or hybrid vehicle comprising a driveshaft according to a first embodiment of the invention, [Fig. 2] Figure 2 is a cross-sectional view of the transmission shaft according to the first embodiment of the invention of Figure 1, [Fig. 3] Figure 3 is an isometric view of the transmission shaft according to the first embodiment of the invention of Figure 1, [Fig. 4] Figure 4 is a cross-sectional view perpendicular to the main axis of revolution of the transmission shaft according to the first embodiment of the invention of Figure 1, [Fig. 5] Figure 5 is another cross-sectional view perpendicular to the main axis of revolution of the transmission shaft according to the first embodiment of the invention of Figure 1, [Fig. 6] Figure 6 is another cross-sectional view perpendicular to the main axis of revolution of the transmission shaft according to the first embodiment of the invention of Figure 1, [Fig. 7] Figure 7 is another cross-sectional view perpendicular to the main axis of revolution of the transmission shaft according to the first embodiment of the invention of Figure 1, [Fig. 8] Figure 8 is a cross-sectional view of a transmission shaft according to a second embodiment of the invention. For clarity, identical or similar elements are identified by identical reference symbols across all figures. DETAILED DESCRIPTION OF IMPLEMENTATION METHODS

[0034] In the description and claims, the terms "external" and "internal" and the orientations "axial" and "radial" will be used to designate, according to the definitions given in the description, elements of the transmission shaft. By convention, the "radial" orientation is directed orthogonally to the principal axis of revolution X of the transmission shaft determining the "axial" orientation, and, from the inside out and away from said axis, the "circumferential" orientation is directed orthogonally to the principal axis of revolution X and orthogonally to the radial direction.

[0035] Figure 1 illustrates a transmission system 1 for an electric or hybrid vehicle, comprising an electric machine (not shown) and a speed reduction device 2 kinematically linked to this electric machine. The speed reduction device 2 transmits the torque from the electric machine to the wheels of the electric or hybrid vehicle.

[0036] The electric machine can be, for example, an induction electric motor, comprising a rotor and a stator, electrically powered by three-phase alternating current from accumulator batteries via a current converter [not shown in Figure 1].

[0037] The electric machine is held on a housing 40a, 40b of the transmission system 1. The housing generally consists of a main housing 40a supporting the electric machine and a closing housing 40b bearing against the main housing 40a at a joint 48, to seal a cavity defined by the main housing 40a and the closing housing 40b. The cavity notably receives a transmission shaft 10 manufactured according to a first embodiment of the invention. The transmission shaft 10 is guided in rotation relative to the housing by means of guide bearings 100. The transmission shaft 10 includes at least one pinion contributing to the reduction of the rotational speed of the electric machine.

[0038] To lubricate the various components of the transmission system 1, the housing 40a, 40b contains lubricating fluid F, for example, oil. The guide bearings 100 and the transmission shaft pinion are partially immersed in the oil. The operation of the speed reduction device 2 then agitates the oil by splashing it throughout the entire internal volume of the housing, ensuring the desired lubrication of the entire system, including the non-immersed parts.

[0039] For the remainder of this description, a reference operational position of the transmission system 1 is defined as the three-dimensional orientation in which the transmission system 1 is installed in a horizontal vehicle. In this reference operational position, the transmission shaft 10 is located above the lubricating oil level. In the remainder of this description, unless otherwise stated, the invention will be described in a reference operational position.

[0040] In the transmission system 1 shown in Figure 1, there is the main housing 40a, the closing housing 40b and the transmission shaft 10, which is free to rotate relative to the housings 40a, 40b around its main axis of revolution X. Two guide bearings 100 support the transmission shaft relative to the housing at its two ends, each guide bearing being inserted into a cylindrical housing 41 provided in the main housing 40a and the closing housing 40b.

[0041] The two guide bearings 100, which include rolling elements 103, require continuous lubrication with lubricating oil. To lubricate the first guide bearing inserted in the main housing 40a, an oil supply channel opens into the housing 41. The oil is then conveyed to the second guide bearing inserted in the closing housing 40b. To facilitate the transport of oil from one guide bearing to the other, a through hole 20 is provided in the center of the drive shaft 10, facilitating the transport of fluid from a first end wall 11 of the shaft to a second end wall 12.

[0042] A lubrication fluid diffuser 50 inserted in the cylindrical housing 41 of the main housing 40a allows the fluid to be injected directly into the hole 20. The lubrication fluid diffuser 50 includes in particular a nozzle 51 which is inserted into an inlet portion 26 of the hole in the transmission shaft at the level of the first end wall 11. The fluid then flows into the cylindrical housing 41 of the closing housing 40b at the level of the second end wall 12. The second guide bearing 100 is thus lubricated.

[0043] The inlet portion 26 is made by drilling from the first end wall 11. The inlet portion 26 is concentric with the main axis of revolution X. To limit efficiency losses, the diffusion nozzle 51 includes an outside diameter which tangents without friction the bore diameter of the hole 20, in particular that of the inlet portion 26.

[0044] The transmission shaft according to the first embodiment of the invention is illustrated in figures 2 to 7.

[0045] To facilitate the transport of the lubricating fluid within the transmission system 1, the transmission shaft according to the invention comprises: - a body 13 having a principal axis of revolution X which has an external surface 14, the first end wall 11 and the second end wall 12 substantially perpendicular to the principal axis of revolution X; - the hole 20 receiving the lubricating fluid, formed from the first end wall 11 and extending inside the body 13, the hole 20 comprising an offset portion 25 having a shape of revolution about a secondary axis of revolution X2 angularly offset with respect to the main axis of revolution X, the offset portion not opening into the external surface 14; - a first conduit 21 connecting the offset portion 25 of the hole to the outside of the body through the external surface 14; - a second conduit 22, distinct from the first conduit 21, connecting the offset portion 25 of the hole to the outside of the body through the external surface 14.

[0046] The first and second conduits 21, 22 supply lubricating fluid to other parts of the lubrication system, including the meshing areas of the speed reduction device 2. The first conduit 21 is cylindrical about a first axis Y1, and the second conduit 22 is cylindrical about a second axis Y2. The first conduit 21 is arranged axially between the first end wall 11 and the second conduit 22.

[0047] Through the first conduit 21, the second conduit 22, and the outlet of the open hole 20, the drive shaft supplies various lubrication points within the transmission system 1. These different lubrication points have specific fluid flow requirements. Thus, for every fluid entering the inlet portion 26, 30% of the flow is found at the outlet of the first conduit 21, then 20% at the outlet of the second conduit 22, and 50% at the outlet of the open hole 20. To adjust the fluid flow rate at the outlet of the conduits and the open hole 20, the first conduit 21 and the second conduit 22 are offset axially and angularly with respect to the main axis of revolution X.

[0048] In this example, the first pipe 21 and the second pipe 22 are perpendicular to the principal axis of revolution X. The intersection of the first pipe 21 with the offset portion 25 creates a first connecting port 21a. The intersection of the second pipe 22 with the offset portion 25 creates a second connection orifice 22a. The first connection orifice 21a of the first pipe 21 with the offset portion 25 is located closer to the main axis of revolution X than the second connection orifice 22a of the second pipe 22 with the offset portion 25.

[0049] In this first embodiment of the invention, the secondary axis of revolution X2 intersects the primary axis of revolution X. The secondary axis of revolution X2 is then angularly offset relative to the primary axis of revolution X. The angle of inclination α of the secondary axis of revolution X2 relative to the primary axis of revolution X is between 2° and 10°, for example 5°. The angular offset of the secondary axis of revolution X2 generates a centrifugal effect on the lubricating fluid passing through the hole 20. The distribution of the fluid within the hole is no longer homogeneous and varies according to the offset.

[0050] At the level of the first end wall 11, the secondary axis of revolution X2 is inscribed in the bore diameter of the hole 20.

[0051] We will now describe, using figures 3 to 7, how the angular orientation of the first pipe 21 relative to the second pipe 22 allows the fluid outlet flow rate to be adjusted.

[0052] Figure 3 is an isometric view of the transmission shaft according to the first embodiment of the invention of Figure 1. In this Figure 3, a first geometric plane PI perpendicular to the principal axis of revolution X passing through the first axis Y1 of the first conduit 21 is shown. A second geometric plane P2 perpendicular to the principal axis of revolution X passing through the second axis Y2 of the second conduit 22 is also shown.

[0053] Figure 4 illustrates a cross-sectional view of the transmission shaft 10 along a plane perpendicular to the main axis of revolution X. This view is taken just upstream of the first pipe 21. The oil distribution is asymmetrical with respect to the secondary axis X2. The oil distribution is a function of the direction of the eccentricity of the secondary axis X2 with respect to the main axis of revolution X.

[0054] In the axial section of figure 4, the eccentricity E of the secondary axis of revolution X2 is visible.

[0055] Figure 5 illustrates a cross-sectional view of the transmission shaft along the first geometric plane PI. Projecting onto this first geometric plane PI, a first angle value α is measured between the first axis Y1 of the first pipe 21 and a first eccentricity vector VI. The first eccentricity vector VI originates at the point of intersection of the principal axis of revolution X with the first geometric plane PI and connects to the point of intersection of the secondary axis of revolution X2 with the aforementioned first geometric plane PI. The direction of the first eccentricity vector VI is determined by these two points of intersection. This direction corresponds to the offset of the secondary axis X2 relative to the principal axis of revolution X. The length of the first eccentricity vector VI corresponds to the distance between the two points of intersection.

[0056] At the first line 21, the oil distribution is asymmetrical with respect to the secondary axis X2. The first line 21 is oriented oppositely to the direction of the first eccentricity vector VI, that is, oriented in the opposite direction to the eccentricity. Only a portion of the lubricating fluid F flows through the first line 21. The first angle value al is equal to 180°.

[0057] Figure 6 illustrates a cross-sectional view of the transmission shaft 10 along a plane perpendicular to the main axis of revolution X. We are located just downstream of the first pipe 21. The distribution of the oil is still asymmetrical with respect to the secondary axis X2 but the oil flow inside the hole 20 is less than that shown in Figure 4.

[0058] Figure 7 illustrates a cross-sectional view of the transmission shaft along the second geometric plane P2. Projecting onto this second geometric plane P2, a second angle value a2 is measured between the second axis Y2 of the second pipe 22 and a second eccentricity vector V2. The second eccentricity vector V2 originates from the point of intersection of the principal axis of revolution X with the second geometric plane P2 and connects to the point of intersection of the secondary axis of revolution X2 with the aforementioned second geometric plane P2.

[0059] At the second pipe 22, the oil distribution is asymmetrical with respect to the secondary axis X2. Only a portion of the lubricating fluid flows through the first pipe 22. The initial angle value al is 90°. The remaining fluid then flows to the outlet of the hole 20 opening at the second wall 12.

[0060] In this example, the first angle value al is greater than the second angle value a2. The lubricating fluid outlet flow rate is adjusted between the first pipe, the second pipe and the fluid outlet at the second end wall, the outlet flow rate at the second end wall being non-zero.

[0061] We will now describe, with reference to figure 8, a transmission shaft 10 according to a second embodiment of the invention which differs from the first embodiment in that the secondary axis of revolution X2 is parallel and distant from the main axis of revolution X.

[0062] The drive shaft 10 includes: - a body 13 having a principal axis of revolution X which has an external surface 14, the first end wall 11 and the second end wall 12 substantially perpendicular to the principal axis of revolution X; - the hole 20 receiving the lubricating fluid, formed from the first end wall 11 and extending inside the body 13, the hole 20 comprising an offset portion 25 having a shape of revolution about a secondary axis of revolution X2 offset radially with respect to the main axis of revolution X, the offset portion not opening into the external surface 14; - a first conduit 21 connecting the offset portion 25 of the hole to the outside of the body through the external surface 14; - a second conduit 22, separate from the first conduit 21, connecting the offset portion 25 of the hole to the outside of the body through the external surface

[0063] In this second embodiment of the invention, the secondary axis of revolution X2 is radially offset with respect to the main axis of revolution X. The eccentricity E of the secondary axis of revolution X2 with respect to the main axis of revolution X is between 2 and 10 mm, for example 5 mm.

[0064] At the level of the first end wall 11, the secondary axis of revolution X2 is inscribed in the bore diameter of the hole 20.

[0065] The body 13 is partially cylindrical and the external surface 14 includes a gear toothing, a groove 27 and a cylindrical bearing centering area.

[0066] The transmission shaft 10 includes raw machined surfaces and machined surfaces suitable for contacting a guide bearing and / or splined surfaces suitable for contacting a pinion.

[0067] The transmission shaft 10 includes a backflow preventer 30, the backflow preventer 30 being interposed between the inlet portion 26 and the offset portion 25 of the hole 20. The backflow preventer 30 includes a cylindrical bore 31 with a diameter greater than the bore diameter of the inlet portion 26.

[0068] The transmission shaft 10 includes an unbalancing device 60, the unbalancing device 60 being in this example a material removal made on the body opposite the misalignment of the secondary axis of revolution X2. The material removal is a drilling made from the second end wall.

[0069] As illustrated in Figure 8, when projected onto a second geometric plane P2 perpendicular to the principal axis of revolution X, the angular position of the second pipe 22 is aligned with the direction of the eccentricity of the secondary axis of revolution X2. The second angle value a2 of the angular position of the second pipe with respect to the second eccentricity vector V2 is equal to 0°. The second pipe 22 is oriented in the direction of the second eccentricity vector V2, that is, oriented in the direction of the eccentricity.

[0070] In this example, the first pipe 21 and the second pipe 22 are perpendicular to the main axis of revolution X. The first pipe 21 is oriented at 90° with respect to the second pipe 22.

[0071] The intersection of the first pipe 21 with the offset portion 25 creates a first connecting orifice 21a. The intersection of the second pipe 22 with the offset portion 25 creates a second connecting orifice 22a. The first connecting orifice 21a of the first pipe 21 with the offset portion 25 is located closer to the principal axis of revolution X than the second connecting orifice 22a of the second pipe 22 with the offset portion 25.

[0072] At the level of the second pipe 22, the distribution of the oil is asymmetrical with respect to the secondary axis X2. Only part of the lubricating fluid flows through the first pipe 22. The rest of the fluid then flows to the outlet of the hole 20 opening at the level of the second wall 12.

[0073] According to another embodiment of the invention, it is possible that the secondary axis of revolution X2 is not parallel and does not intersect the main axis of revolution X. The secondary axis of revolution X2 is then angularly and radially offset with respect to the main axis of revolution X. The angle of inclination a of the secondary axis of revolution X2 with respect to the main axis of revolution X is between 2° and 10° and the eccentricity E of the secondary axis of revolution X2 with respect to the main axis of revolution X is between 2 and 10 mm.

[0074] The invention is not limited to the examples just described. For example, the invention can be applied to a drive shaft directly connected to an output shaft of an electric machine rotor.

Claims

DEMANDS 1. Drive shaft (10) for electric or hybrid vehicle transmission system, comprising: - a body (13) having a principal axis of revolution (X) which has an external surface (14), a first end wall (11) and a second end wall (12) substantially perpendicular to the principal axis of revolution [X); - a hole (20) suitable for receiving a lubricating fluid, formed from the first end wall (11) and extending into the body (13), the hole comprising an offset portion (25) having a shape of revolution about a secondary axis of revolution (X2) offset angularly and / or radially with respect to the main axis of revolution (X), the offset portion (25) not opening into the external surface (14); - a first conduit (21) connecting the offset portion (25) of the hole to the outside of the body through the external surface (14); - at least one second conduit (22) distinct from the first conduit communicating the offset portion (25) of the hole to the outside of the body through the external surface (14), the first conduit (21) extending radially along a first axis (Y1) and the second conduit (22) extending radially along a second axis (Y2) are offset axially and angularly with respect to the main axis of revolution (X).

2. A transmission shaft (10) according to the preceding claim, wherein the first conduit (21) is arranged axially between the first end wall (11) and the second conduit (22), and wherein, in projection onto a first geometric plane (PI) perpendicular to the principal axis of revolution (X), a first angle value (a1) is measured between the first axis (Y1) of the first conduit (21) and a first eccentricity vector (VI), and in projection onto a second geometric plane (P2) perpendicular to the principal axis of revolution (X), a second angle value (a2) is measured between the second axis (Y2) of the second conduit (22) and a second eccentricity vector (V2). first eccentricity vector (VI) starting from the point of intersection of the principal axis of revolution (X) with the first geometric plane (PI) to join the point of intersection of the secondary axis of revolution (X2) with said first geometric plane (PI), the second eccentricity vector (V2) starting from the point of intersection of the principal axis of revolution (X) with the second geometric plane (P2) to join the point of intersection of the secondary axis of revolution (X2) with said second geometric plane (P2), the first angle value (al) is greater than the second angle value (a2), the first and second angle values ​​(al, a2) being less than or equal to 180°.

3. Transmission shaft (10) according to claim 1 or 2, wherein the first conduit (21) is arranged axially between the first end wall (11) and the second conduit (22), the connection orifice (21a) of the first conduit (21) with the offset portion (25) is located closer to the main axis of revolution (X) than the connection orifice (22a) of the second conduit (22) with the offset portion (25).

4. Transmission shaft (10) according to any one of the preceding claims, wherein the first conduit (21) and the second conduit (22) are perpendicular to the main axis of revolution (X).

5. Transmission shaft (10) according to any one of claims 1 to 4, wherein the first conduit (21) and the second conduit (22) are perpendicular to the secondary axis of revolution (X2).

6. Transmission shaft (10) according to claim 2, wherein in projection onto the second geometric plane (P2) perpendicular to the principal axis of revolution (X), the angular position of the second conduit (22) is aligned with respect to the direction of the eccentricity of the secondary axis of revolution (X2), so that the second angle value (a2) of the angular position of the second conduit (22) with respect to the second eccentricity vector (V2) is equal to 0°.

7. Transmission shaft (10) according to any one of the preceding claims, wherein the hole (20) is a through hole which passes through the body (13) from the first end wall (11) to convey the lubricating fluid to the second end wall (12).

8. Transmission shaft (10) according to any one of the preceding claims, wherein the hole includes a lubricating fluid inlet portion (26) concentric to the main axis of revolution (X) and the offset portion (25) communicates into the inlet portion.

9. Transmission shaft (10) according to any one of the preceding claims, wherein the secondary axis of revolution (X2) is secant to the main axis of revolution (X), the secondary axis of revolution (X2) is then angularly offset with respect to the main axis of revolution (X).

10. Transmission shaft (10) according to any one of claims 1 to 8, wherein the secondary axis of revolution (X2) is parallel and distant from the main axis of revolution (X), the secondary axis of revolution (X2) is radially offset with respect to the main axis of revolution (X).

11. Transmission shaft (10) according to any one of claims 1 to 8, wherein the secondary axis of revolution (X2) is not parallel and does not intersect the main axis of revolution (X), the secondary axis of revolution (X2) is angularly and radially offset with respect to the main axis of revolution (X).

12. Transmission shaft (10) according to claim 8, comprising an anti-backflow device (30), the anti-backflow device (30) being interposed between the input portion (26) and the offset portion (25).

13. Transmission shaft (10) according to any one of the preceding claims, wherein the offset portion (25) comprises a conical shape flaring out towards the second end wall (12).

14. Transmission system (1) for electric or hybrid vehicles comprising: - a housing (40a, 40b); - a transmission shaft (10) according to any one of the preceding claims, movable in rotation relative to the casing around its main axis of revolution (X); - a guide bearing (100) supporting the transmission shaft relative to the housing which includes bearing elements (103), the guide bearing being inserted in a cylindrical housing (41) provided in the housing; - a lubricating fluid diffuser (50) inserted in the cylindrical housing (41) of the housing; in which the lubricating fluid diffuser (50) includes a diffusion nozzle (51) inserted in the hole (20) of the transmission shaft (10) at the level of the first end wall (11).

15. Transmission system (1) according to the preceding claim, in which the diffusion nozzle (51) comprises an outer diameter which tangents without friction to the bore diameter of the hole (20) 16. Electric machine for transmission system comprising: - a stator; - a rotating rotor that moves around a machine axis comprising a hollow torque output shaft, the rotor being housed inside the stator; and - a transmission shaft (10) according to any one of claims 1 to 13, rotationally fixed to the hollow torque output shaft via a splined connection.

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