- electromotive assembly with an electric machine, a differential mechanism and rotary mounting of floating shafts

Abstract

Electromotive assembly comprising a casing (CM), a differential mechanism (DF) and an electric machine (MEL) having a rotor (9) with a rotor shaft (1), the differential mechanism (DF) comprising a planet carrier element (2) rotated by the rotor shaft, pinion gears (23, 24) rotatably mounted on the planet carrier, a first sun gear (21) and a second sun gear (22), a short drive shaft (A1), bearing splines and mounted on the one hand in the first sun gear, and on the other hand in a first primary pinion, a long drive shaft (A2), bearing splines and mounted on the one hand in the second sun gear, and on the other hand in the second primary pinion, wherein the mounting of the rotating parts calls for two bearings (B1, B2) for rotatably mounting the rotor shaft, a bearing (B3) for rotatably mounting the first primary pinion, and a bearing (B4) for rotatably mounting the second primary pinion.

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION: Electromotor assembly with electric machine, differential mechanism and floating shaft rotation assembly

[0003] The present invention relates to a rotating assembly of floating shafts in a rotating assembly of rotating parts in an electromotor assembly with electric machine and differential mechanism.

[0004]

[0002] When discussing the differential function present on a front or rear driven axle of a conventional motor vehicle, the differential device comprises one input and two outputs, and each of the two outputs drives one of the axle's wheels via one or more constant velocity joints. There is generally a reduction gear between the electric motor and the differential input. Therefore, there is only one reduction gear per axle in these configurations. In other words, the reduction gear is located upstream of the differential in the drivetrain.

[0005] The differential device must be sized to accommodate a significant torque, and its components must be sized accordingly. This makes the differential bulky and expensive.

[0006] This bulkiness is detrimental to good integration into the vehicle's architecture, and the differential occupies space that could be allocated to other functions, including increasing the storage compartment volume.

[0007]

[0005] Among the ideas for improving the size and increasing the integration capacity of the electric motor-based unit, one can consider the idea of ​​moving the differential function to the motor output and placing a reduction gear on each of the differential outputs. Since the differential rotates faster, the torque it must transmit is therefore lower, and its mechanical dimensions allow for a reduced size.

[0008] Some have already proposed installing the differential in the electric motor rotor, upstream of gearboxes in the case of electric train or vehicle axle drives, as taught, for example, in document US11394270. However, it should be noted that US11394270 proposes placing the differential in the center of the hollow shaft connected to the rotor. It is also worth noting that US11394270 instructs the use of four ball bearings inside the hollow shaft, which is a very bulky and expensive solution.

[0009] Therefore, there remains a need to propose a more economical solution for the rotational mounting of the differential mechanism in a hollow rotor shaft and its output shafts.

[0010] To this end, an electromotor assembly is proposed here comprising a housing, a differential mechanism and an electric machine comprising a rotor with a rotor shaft, the rotor shaft having a tubular hollow body extending from a first axial end to a second axial end along a main axis of the electric machine, the differential mechanism being arranged at the first axial end and comprising a planet carrier element driven in rotation by the rotor shaft, at least two planet gears mounted for rotation on the planet carrier, a first planetary gear and a second planetary gear meshing with the planet gears,

[0011] - a short drive shaft, splined, mounted on one side in the first planetary gear, and on the other side in a first primary gear,

[0012] - a long drive shaft, bearing splines at least at each end, mounted on one side in the second planetary gear, and on the other side in the second primary gear, the first and second primary gears forming outputs of the electromotor assembly, characterized in that the rotating assembly of rotating parts provides:

[0013] - two bearing elements for mounting the rotor shaft relative to the housing,

[0014] - a bearing element for the rotational mounting of the first primary gear relative to the housing,

[0015] - a bearing element for the rotational mounting of the second primary pinion relative to the housing.

[0016]

[0009] Thanks to these arrangements, the drive shafts are guided in rotation via the differential mechanism, and as will be seen later, this assembly can be described as a floating assembly.

[0017]

[0010] There is no over-static effect; a possible rumbling of the electromotor assembly under torque is avoided. As will be seen later, the proposed assembly promotes self-centering during rotation of the short and long drive shafts.

[0018]

[0011] It is noted that the first primary pinion and the second primary pinion can directly drive homokinetic transmissions to the wheels or, conversely, each of these primary pinions can form an input of a speed reducer which in turn drives the homokinetic transmissions.

[0019] A rotating assembly with only 4 bearings in total is thus proposed; this is a particularly relevant solution from the point of view of cost.

[0020] Put another way, the short and long drive shafts are not guided directly by one or more bearings, they are carried by the differential mechanism, itself received in the rotor shaft, and it is the rotor shaft that is in contact with the bearings.

[0021] We note that there is no contact or sliding contact between the long drive shaft and the rotor shaft, even though the long drive shaft is housed inside the rotor shaft.

[0022]

[0015] According to an advantageous embodiment, radial play is provided at the splines between the second primary pinion and the long drive shaft, and radial play is provided at the splines between the first primary pinion and the short drive shaft.

[0023]

[0016] Accordingly, a possible slight misalignment (static and / or dynamic) is tolerated by this floating assembly on the output spline side. The proposed assembly promotes self-centering on the output spline side, which complements the floating assembly in the differential mechanism.

[0024]

[0017] According to one embodiment, at each planetary gear, a pressure washer is interposed between the planetary gear and a bearing flat receiving a branch of the planet carrier element. Each pressure washer provides an elastic force directed radially inwards, providing a self-centering effect that tends to push the planetary gear in question towards the axis.

[0025]

[0019] According to one option, the satellite carrier element is cross-shaped, each arm carrying a satellite pushed on its back towards the axis by a pressure washer.

[0026] According to one embodiment, the rotating assembly is devoid of bearings inside the tubular hollow body of the rotor shaft.

[0027] This allows the use of larger diameter bearing components, with larger raceways and larger balls, which are more robust and more durable.

[0028] Advantageously, the rotor shaft can have a reduced diameter, for example, less than 70 mm. In one example, the rotor shaft diameter is less than 62 mm. Generally, in the configuration proposed here, the rotor shaft diameter is much smaller than those specified in documents EP0760549 or US11394270. The configuration proposed here offers excellent compactness and enhanced integration possibilities within the vehicle architecture.

[0029]

[0023] According to one embodiment, the second long drive shaft has a length of at least 80 mm, and preferably at least 100 mm.

[0030] For example, the long drive shaft has a length close to the axial length of the rotor. Despite this significant length, and the absence of a bearing to directly guide the rotation of the long drive shaft, the proposed floating mounting solution is entirely satisfactory.

[0031] According to one embodiment, the short drive shaft has symmetry with respect to a median plane transverse to the axis, and preferably the long drive shaft has symmetry with respect to a median plane transverse to the axis.

[0032] A potential risk of mounting an intermediate drive shaft backwards is thus eliminated.

[0033] According to one embodiment, the short drive shaft and the long drive shaft are hollow.

[0034] Lubricating oil can be passed through the drive shafts. Despite some flexibility in bending, the drive shafts retain sufficient torsional rigidity.

[0035] Since the longer drive shaft is longer, its cross-sectional area and outer diameter are larger than those of the shorter drive shaft. The axial channel of both shafts can be of equal dimensions.

[0036]

[0030] According to one embodiment, the axial retention of the short shaft is achieved by means of two circlips, each received in a groove.

[0037] [031 j According to one embodiment, the axial retention of the long shaft is achieved by means of a shoulder and a ring received in a groove.

[0038]

[0032] The present invention also relates to an electromotor group comprising an electromotor assembly as described above, a first reducer and a second reducer, the electric machine being interposed between the first reducer and the second reducer.

[0039]

[0033] The first primary gear forms the input of the first speed reducer and the second primary gear forms the input of the second speed reducer. In one embodiment, the first and second reducers are identical, the second reducer being rotated 180° relative to the first reducer.

[0040] This reduces industrial diversity.

[0041] According to one embodiment, a bearing support is provided arranged in a gearbox housing, and a bearing support is provided arranged in a gearbox housing.

[0042]

[0037] According to one embodiment, a bearing is provided outside the rotor shaft, arranged to surround the second planetary gear, in the same axial position, for guiding the transmission device in rotation.

[0043] The present invention also relates to a motor vehicle, comprising at least one electromotor assembly as described above.

[0044] The vehicle in question may be an electric or hybrid vehicle.

[0045] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which:

[0046] - [Fig.1] illustrates a front view of an example of a motorized axle of a motor vehicle, with an electromotor assembly in which the present invention is implemented;

[0047] - [Fig.2] schematically represents, in axial section view, an example of an electromotor group in which the present invention is implemented;

[0048] - [Fig.3] schematically represents in exploded axial section view the example of electromotor group of figure 2;

[0049] - [Fig.4] schematically represents, in axial section view, an example of an electromotor assembly in which the present invention is implemented;

[0050] - [Fig.5] represents an exploded view of the differential device, allowing to illustrate the elements involved in the proposed differential device;

[0051] - [Fig.6] represents in axial section view of details of the first end area of ​​the electromotor assembly;

[0052] - [Fig.7] represents an axial cross-sectional view of details of the axial area of ​​the electrical machine;

[0053] - [Fig.8] represents an axial cross-sectional view of details of the area of ​​the short intermediate shaft;

[0054] - [Fig.9] represents in cross-sectional view to the axis of an example of the realization of a splined coupling, with a radial clearance relative to the floating assembly.

[0055]

[0041] In the various figures, the same reference numerals designate identical or similar elements. For the sake of clarity, some elements are not necessarily shown to scale.

[0056] Regarding the terminology related to the differential device, it should be noted that "planetary gears" can be simply called "planetary" and "satellite gears" can be simply called "satellites".

[0057]

[0043] Figure 1 shows an axle of a motor vehicle, in this case a motorized axle in which an electromotor unit GEM drives right and left wheels referenced 47 according to a first embodiment.

[0058] In the illustrated example, it is an electric motor in a hybrid or pure electric vehicle.

[0059] As will be seen in detail later, the rotor shaft drives a differential device DF, each of whose outputs in turn drives a speed reducer (R1, R2). Each of the reducers R1, R2 includes an output pinion which drives the respective wheel 47 by means of a homokinetic transmission T1, T2 as known per se.

[0060] The MEL designation refers to the electric machine with a stator and a rotor, designated 9. The electric machine operates as a motor or a generator depending on the operating conditions. The UU designation refers to an electromotor assembly that includes the machine and the differential device DF.

[0061] The reference GEM designates the electromotor group which includes the electric machine MEL, the differential device DF, the left reducer R1 and the right reducer R2.

[0062] Figures 2 and 3 show the electromotor assembly in cross-section, which includes the electric machine MEL and the differential device DF. The electric machine comprises a housing CM, composed here of three parts: a main housing C0 in the shape of a sleeve, a first end housing C1 and a second end housing C2.

[0063]

[0049] The electric machine comprises a stator and a rotor 9. The illustrated electric machine is radial flux, but the invention can also be applied to an axial flux electric machine.

[0064] The rotor includes a rotor shaft 1, of tubular shape. The rotor shaft 1 is connected to the housing by a mounting rotating around the axis Y1 by means of two bearings B1 and B2.

[0065] Bearing B1 is mounted in an internal bearing surface of the first end housing, labeled C1. Bearing B2 is mounted in an internal bearing surface of the second end housing, labeled C2.

[0066]

[0053] Figure 2 illustrates the position of the differential device DF in the electromotor assembly UU relative to the electric machine. The differential device drives intermediate drive shafts, more specifically the short intermediate shaft A1 on the left and the long intermediate shaft A2 on the right.

[0067] On the left in Figures 2 and 4, the output pinion 31 forms one of the outputs of the electromotor assembly UU. The output pinion 31, also called the first primary pinion, is driven by the short intermediate shaft A1. On the right in Figures 2 and 4, an output pinion 32 forms the other output of the electromotor assembly UU. The output pinion 32, also called the second primary pinion, is driven by the long intermediate shaft A2.

[0068] When the vehicle travels along a curved road, one of the drive shafts rotates faster than the other as is known in itself, which causes each satellite pinion to rotate on itself as is known, which is called differential slippage.

[0069] The short drive shaft A1, once assembled, drives the first reducer R1 via the output pinion 31. The long drive shaft A2, once assembled, drives the second reducer R2 via the output pinion 32.

[0070]

[0057] The assembly between the drive shafts and the primary gears is based on a splined coupling as known per se. As shown in Figure 9, the drive shafts are equipped with external splines CN1, CN2, while the primary gears are equipped with internal splines CN3. The planetary gears are also equipped with internal splines CN4.

[0071] [0 The rotor shaft, labeled 1, is hollow and configured to house the long drive shaft A2. The rotor shaft 1 is integral with the machine's rotor 9. [0 The rotational connection between the rotor and the drive shaft can be achieved by a shrink-fitting process. In the illustrated example, grooves 1k are provided in the rotor shaft, which receive internal projections of the rotor's ferromagnetic plates. The grooves and projections cooperate by complementary shapes.

[0072]

[0060] The rotor shaft 1 has a tubular body and extends from a first axial end marked E1 to a second axial end marked E2 along a main axis marked Y1.

[0073] As seen in figure 5, the rotor shaft 1 includes housings 18 made in the tubular body at the first axial end E1. These housings 18 are intended to receive and drive a planet carrier element 2 which is part of the differential mechanism denoted DF.

[0074] The differential mechanism DF includes a planet carrier element 2 received in the housings 18 via bearings described later. The differential mechanism DF is of the bevel gear type here.

[0075]

[0063] Each housing 18 has an opening directed axially opposite to the second axial end E2 to allow end mounting on the side of the first axial end E1, in the direction of E2.

[0076] The planet carrier element 2 is driven in rotation by the rotor shaft 1. The transmission device includes four planet gears (23, 24, 25, 26) mounted for rotation on the planet carrier 2.

[0077]

[0065] The satellite carrier element 2 is cross-shaped with four identical arms. Each arm end includes an end trunnion 27 around which a satellite mounted at that location can rotate.

[0078] Each of the branches of the cross-shaped satellite carrier element extends along a local axis WR perpendicular to the main axis.

[0079] The satellite carrier element 2 is made of steel, just like the satellites and planetary gears.

[0080] The DF differential mechanism includes a first planetary pinion 21 and a second planetary pinion 22.

[0081] Each planetary gear meshes with the satellite gears. The satellite gears do not mesh with each other.

[0082] The first planetary gear 21 is suitable for driving the short drive shaft A1 via the additional splines mentioned above. The second planetary gear 22 is suitable for driving the long drive shaft A2 via the additional splines mentioned above.

[0083]

[0071] The number of satellite gears could be two. Thus, generally, the transmission device comprises at least two satellite gears (23, 25).

[0084]

[0072] A bearing 5 is provided interposed between each housing 18 and the satellite carrier 2. The bearing 5 allows the torque force produced by the rotor and allocated to the rotor shaft to be absorbed.

[0085]

[0073] The bearing 5 can be mushroom-shaped. For example, each bearing 5 comprises a head received in the respective housing 18 opposite, and a bearing tube around which a satellite is mounted.

[0086] Each of the bearing heads includes two straight edges 55 parallel to the main axis Y1 orthogonal to the local axis of the bearing tube.

[0087]

[0075] Each of the bearings includes a front edge 56 which, once assembled, is flush with the free edge 1a of the shaft.

[0088]

[0076] The head is outwardly convex with an entry chamfer. The curvature follows the general profile of the outer wall of the rotor shaft once the bearing is in place. On the inner side, the head includes an annular flat 59 on which a washer, which is discussed below, bears. The annular flat surrounds the base of the bearing tube.

[0089]

[0077] The bearing tube receives on its inner side a trunnion 27 of the planet carrier 2 which is received in an inner bearing. Furthermore, the bearing tube receives on its outer side, i.e. on its external cylindrical surface, the inner bore of the planet carrier which can rotate at this point.

[0090]

[0078] The second planetary gear 22 bears against a front face of an annular-shaped planetary thrust bearing 6. The planetary thrust bearing 6 includes a rear face which bears against a shoulder 160 provided in the rotor shaft 1.

[0091]

[0079] Advantageously, pressure washers (4,4') are provided on the back of the satellites and planetary gears.

[0092] Pressure washers are non-flat washers at rest. They exhibit a degree of elasticity and can return to a flat shape under compression. The 4" pressure washers on the back of the planetary gears contribute to compensating for axial play. The 4" pressure washers on the back of the satellite gears contribute to compensating for transverse play. Pressure washers also contribute to the self-centering of drive shafts during rotation. Furthermore, they can eliminate hysteresis when torque direction changes.

[0093]

[0081] Each pressure washer 4 provides an elastic force directed radially inwards, providing a self-centering tending to push the satellite concerned towards the axis.

[0094] The invention proposes to use a differential cover noted 7 inserted externally on the first axial end E1 of the rotor shaft 1.

[0095] The differential cover 7 is formed as a metal ferrule with a material thickness between 2 mm and 5 mm, preferably with a material thickness between 2.5 mm and 4 mm.

[0096] The differential cover includes a trim skirt 70 delimited by a free circular border 74.

[0097] As seen in the figures, the differential cover 7 includes an axial opening 72 configured to allow passage for the first drive shaft A1 which can be rotationally fixed to the first planetary pinion 21.

[0098] Furthermore, the rotor shaft 1 is configured to house the second drive shaft A2 up to an axial through opening noted 19 at the second axial end E2 of the rotor shaft.

[0099] The differential cover 7 is inserted onto the rotor shaft until the inner annular bearing comes into contact with the free end 1a of the rotor shaft.

[0100] The differential cover 7 can be fixed by shrink fitting onto the rotor shaft 1. The overlap area of ​​the differential cover on the rotor shaft is substantial, resulting in a solid attachment of the differential cover to the shaft 1.

[0089] The wound rotor is electrically activated via excitation tracks P1, P2. As can be seen in Figure 7, the excitation tracks are arranged in an annular fashion at the second end E2 of the shaft opposite the position of the differential device.

[0101] The two excitation tracks P1, P2 are separated by an insulating ring. Opposite them is a system of friction pads, one or more pads rubbing against the excitation tracks.

[0102] Gearboxes The first gearbox R1 includes a gearbox housing marked CR1.

[0103] The first reducer R1 includes an input pinion 31, a fast gear 41, a slow gear 42, the slow gear comprising a toothed output hub, into which a toothed shaft 61 of the homokinetic transmission T1 to a wheel is inserted (see figure 2).

[0104] The input pinion 31 is guided in rotation by a bearing B3.

[0105] The center distance between the axis of the high-speed gear 41 and the main axis Y1 is denoted ER and is here between 100 mm and 130 mm. This is the same center distance between the axis of the high-speed gear 41 and the axis of the low-speed gear 42. Indeed, advantageously, the input and output of the first reducer are coaxial, on the axis Y1.

[0106] The shaft of the high-speed gear 41 is guided in rotation by a bearing B5 and a bearing B7.

[0107] The slow-speed gear 42 forms the output of the reducer.

[0108] The shaft of the slow gear 42 is guided in rotation on the output side by a bearing B6 and on the opposite side by a needle bearing N1 mounted on an inner bearing of the input pinion 31 (see figures 2 and 6).

[0109] The fast gear 41 comprises a first toothed sector of large diameter 41a, radially external, and a second toothed sector of small diameter 41b, radially external, which drives a first toothed sector of large diameter 42a of the slow gear 42, radially external.

[0110]

[0100] The slow gear 42 includes radially internal splines noted 42b to receive the splines 66 of the output member 61 at the end of the constant velocity joint T1.

[0111] The second reducer R2 includes an input pinion 32, a high-speed gear 41, a low-speed gear 42, the low-speed gear comprising a toothed output hub, into which the output member 62 is inserted at the end of the constant velocity joint T2 towards the other wheel.

[0112] The second reducer R2 includes a reducer housing marked CR2.

[0113]

[0103] The second reducer R2 is similar or even identical to the first reducer and the description made for the first reducer applies to the second reducer R2.

[0114] Advantageously, two identical reducers can be used, one being rotated 180° relative to the other around an axis perpendicular to Y1.

[0115]

[0105] It is noted that each reducer comprises five bearings (four ball bearings B3, B5, B6, B7 and one needle bearing N1) to guide in rotation three rotating parts namely the input pinion, the high-speed gear and the low-speed gear.

[0116]

[0106] Gear cascade reducers are very reliable and inexpensive. Smaller cascade reducers than those shown in the figures could be used.

[0117]

[0107] Each gearbox housing is formed in two parts as seen in figures 2 and 3. Each gearbox housing CR1, CR2 is fixed to the machine housing CM at one end.

[0118] [1 Once the assembly is complete, the MEL electric machine is interposed between the two reducers. The housings of the two reducers (CR1, CR2) are fixed to the CM housing of the electric machine to form a single assembled mechanical unit.

[0119]

[0109] Rotating mounting of drive shafts The rotating mounting of the rotating parts is therefore based on:

[0120] - two bearing elements B1, B2 for mounting the rotor shaft 1 relative to the housing CM,

[0121] - a bearing element B3 for the rotational mounting of the first primary pinion 31, receiving the short drive shaft A1, relative to the housing,

[0122] - a bearing element B4 for the rotational mounting of the second primary pinion 32 receiving the long drive shaft A2, relative to the casing.

[0123] It is noted that the DF transmission device is devoid of bearings inside the rotor shaft, which increases the compactness of the differential mechanism as already mentioned.

[0124] Figure 4 illustrates a configuration where the presence of a reducer is optional. In this case, on the side of the first end E1, the bearing B3 is received in a bearing of a housing C3 which is either integrally formed from the housing of the first end C1 or forms an added part fixed to the housing of the first end C1.

[0125] Similarly, on the side of the second end E2, the bearing B4 is received in a bearing of a housing C4 which is made entirely from the housing of the second end C2 or which is an added part fixed to the housing of the second end C2.

[0126] It is thus understood that the C3 and C4 housings may or may not be an integral part of the CM machine housing.

[0127] Bearing B1 is arranged to surround the second planetary gear 22, in the same axial position, for rotational guidance of the transmission device.

[0128] In the axial zone inside bearing B1, the pressure washers 4, described in detail above, contribute to guiding and centering the long drive shaft A2 via the planetary and satellite gears. The same applies to guiding and centering the short drive shaft A1.

[0129] As shown in Figure 8, the short shaft A1 extends from a first end 98 to a second end 99. The axial retention of the short shaft A1 is achieved by means of two circlips J7, J8, each received in an annular groove. Two small shoulders 95, 96 are provided in the splined hub of the primary gear 31. The circlips J7, J8 are positioned on either side of these shoulders 95, 96.

[0130] Regarding the long drive shaft A2, it is noted that, apart from the two end portions A22 equipped with splines, the main central portion is devoid of splines and has a larger outside diameter D20, which allows it to have sufficient torsional rigidity and not substantially far from the torsional rigidity of the short drive shaft.

[0131] The main central portion without splines extends over most of the total length LA2 of the long drive shaft A2, for example at least 85% of the total length LA2.

[0132] The axial support of the long shaft A2 is achieved, at the level of the second end E2, by means of a shoulder A25 and a ring received in an annular groove.

[0133] According to an advantageous embodiment, the short drive shaft A1 has symmetry with respect to a median plane W1 transverse to the axis (see figure 8).

[0134]

[0122] Similarly, the long drive shaft A2 exhibits symmetry with respect to another median plane W2 transverse to the axis (see Figure 7).

[0123] Dimensioning

[0135] In the drive shafts, the axial channels 75 and 76 for the passage of oil can have a diameter between 4 mm and 6 mm.

[0136]

[0125] As illustrated in Figure 9, the diameters DC1 and DC2 of the pitch circles of the inner and outer splines can be between 12 mm and 16 mm. The outer diameter D20 of the central section of the long drive shaft A2 can be between 22 mm and 26 mm.

[0137]

[0126] According to a particular application example on a motor vehicle drive axle, the outside diameter of the rotor shaft D1 is between mm.

[0138] This applies to an engine torque to be passed up to the order of 800 Nm.

[0139] Regarding the relative dimensions, with reference to Figures 2 and 3, we note that in the illustrated embodiment, D1 / L9 < 0.5, where L9 is the axial length of the rotor. We also have D1 / D9 < 0.4, where D9 is the rotor diameter. Therefore, the diameter D1 is small, even though the rotor shaft houses the differential mechanism.

[0140]

[0129] Furthermore, we can have D1 / DM < 0.25 where DM is the diameter of the electrical machine MEL.

[0141]

[0130] The axial length of the electromotor unit is denoted LG (see figure 2). The rotor shaft 1 has a length denoted L1.

[0142] The long drive shaft A2 has a length, denoted LA2, of at least 80 mm. In one example, LA2 is at least 100 mm, but can nevertheless be much larger, for example 250 mm, 300 mm, 350 mm or more, depending on the power and torque required for the electric machine.

[0143]

[0132] In practice, the length LA2 of the long drive shaft A2 can be close to the length L1 of the rotor shaft 1.

[0144] The short drive shaft A1 has a length noted LA1 which can be between 30 mm and 50 mm.

[0145] The UU electromotor assembly therefore integrates the differential function in a form factor that differs very little from a form factor of a standalone electric machine for the same power characteristics.

[0146]

[0135] The combination described above allows the differential device to be sized as precisely as possible and to be housed inside a rotor shaft of an electric machine, here on one end of this shaft opposite the electrical excitation tracks when the rotor is wound.

[0147]

[0136] Lubrication

[0148]

[0137] The electromotor assembly includes a lubrication system comprising an oil pump to provide a forced flow of oil.

[0149]

[0138] The forced oil flow is brought to a first oil inlet point H1 on the housing CR1 of the first reducer.

[0150]

[0139] The entry point H1 is located at a distance from the axis, with an inlet channel F10, the inlet channel being formed in the housing CR1 of the first reducer R1, and extending radially in the direction of the axis. The inlet channel F10 opens into an annular volume G4 which acts as an intermediate buffer volume and which is delimited by a specific axial double-lip seal 11.

[0151] The annular volume G4 communicates with a second annular volume G5 of smaller diameter, located radially inside the buffer volume G4.

[0152] The forced oil flow continues towards the axis through radial holes F11 provided in the pinion 61 driven by the gearbox output. This pinion 61, with a splined hub 66, forms part of the constant velocity transmission T1 to the wheel 47.

[0153]

[0142] The oil enters the axial zone through a blind hole cavity 68 formed in the journal 63. The oil path then passes through a central passage 42k of the slow gear 42, and then through a central passage 75 of the first short intermediate shaft A1. A delivery nozzle 17 is provided which extends axially through the hub of the slow gear 42 of the reducer and the first short intermediate shaft A1 via the axial passage 75.

[0154]

[0143] The axial delivery cannula 17 brings the forced oil flow to the central orifice 2H of the planet carrier element 2, passing as shown above through the central passage 42k of the slow gear 42 and the central passage 75 of the short shaft A1.

[0155] A groove is provided at the first end of the delivery cannula, receiving an O-ring 175. The forced oil flow is directed inside the delivery cannula 17.

[0156] On the outside of the output pinion 61 of the reducer, there is a lip seal noted 14, of known structure and functions, as well as a dust cover J15 (see figure 6).

[0157]

[0146] The intermediate buffer volume G4 is delimited by the lip seal 14, the axial double lip seal 11, and an annular portion 140 of the housing CR1

[0158] The maximum rotational speed of the rotor is important, for example at least 15,000 rpm, or even 20,000 rpm.

Claims

DEMANDS 1. Electromotor assembly (UU) comprising a housing (CM), a differential mechanism (DF) and an electric machine (MEL) comprising a rotor (9) with a rotor shaft (1), the rotor shaft having a tubular hollow body extending from a first axial end (E1) to a second axial end (E2) along a main axis (Y1) of the electric machine, the differential mechanism (DF) being arranged at the first axial end (E1) and comprising a planet carrier element (2) driven in rotation by the rotor shaft, at least two planet gears (23, 24) mounted for rotation on the planet carrier, a first planetary gear (21) and a second planetary gear (22) meshing with the planet gears, - a short drive shaft (A1), bearing splines, mounted on one side in the first planetary gear (21), and on the other side in a first primary gear (31), - a long drive shaft (A2), bearing splines at least at each end, mounted on one side in the second planetary gear (22), and on the other side in the second primary gear (32), the first and second primary gears forming outputs of the electromotor assembly, characterized in that the rotating assembly of rotating parts provides: - two bearing elements (B1, B2) for mounting the rotor shaft relative to the housing, - a bearing element (B3) for the rotational mounting of the first primary pinion (31) relative to the housing, - a bearing element (B4) for the rotational mounting of the second primary pinion (32) relative to the housing.

2. Electromotor assembly according to claim 1, in which a radial clearance is provided at the location of the splines (CN3, CN2) between pinion (32) and (A2) long side, and a radial clearance is provided at the location of the splines (CN3, CN1) between pinion (31) and (A1) short side.

3. Electromotor assembly according to any one of claims 1 to 2, wherein a pressure washer (4) is provided at the location of each satellite pinion, interposed between the satellite and a bearing flat receiving a branch of the satellite carrier element.

4. Electromotor assembly according to any one of claims 1 to 3, wherein the rotating assembly is devoid of bearing inside the tubular hollow body of the rotor shaft (1).

5. Electromotor assembly according to any one of claims 1 to 4, wherein the long drive shaft (A2) has a length (LA2) of at least 80 mm.

6. Electromotor assembly according to any one of claims 1 to 5, wherein the short drive shaft (A1) has symmetry with respect to a median plane transverse to the axis, and preferably the long drive shaft (A2) has symmetry with respect to a median plane transverse to the axis.

7. Electromotor assembly according to any one of claims 1 to 6, wherein the short drive shaft (A1) and the long drive shaft (A2) are hollow.

8. Electromotor group (EMG) comprising an electromotor assembly according to any one of claims 1 to 7, a first reducer (R1) and a second reducer (R2), the electric machine being interposed between the first reducer and the second reducer.

9. Electromotor unit according to claim 8, in which a bearing support (B3) is provided in a gearbox housing (CR1), and a bearing support (B4) is provided in a gearbox housing (CR2).

10. Motor vehicle, preferably electric or hybrid, comprising an electromotor unit (UU) according to any one of claims 1 to 7.

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