Electric motor unit with lubrication system including an oil delivery nozzle

Abstract

Electromotor group (EMG) comprising an electromotive unit with an electric machine (EMM) having a hollow tubular rotor shaft (1), a differential mechanism (DF), a first reduction gear (R1), comprising a reduction gear housing (CR1), adjacent to the electromotive unit, a first intermediate shaft (A1), hollow and rotationally fixed to a planetary gear, driving the first reduction gear, an inlet of a forced oil flow (FH), at a first inlet point (H1) on the housing of the first reduction gear, with a delivery nozzle (17) extending from a first axial position in an axial zone of the first reduction gear to a central region of the differential mechanism, the delivery nozzle passing through a central bore (75) of the first intermediate shaft, a first end of the delivery nozzle being arranged in an axial blind hole (68) of an output member (61) of the first reduction gear,so that the cannula allows the forced oil flow to be conveyed to the heart of the differential mechanism. Figure from the abstract: Fig. 3,

Description

Title of the invention: Electric motor unit with lubrication system including an oil delivery nozzle

[0001] The present invention relates to an electromotor unit for a vehicle axle, said electromotor unit comprising an electric machine, a differential and at least one reducer, said electromotor unit comprising a lubrication system.

[0002] A transmission system which includes a differential and possibly a reduction gear or a gearbox is generally lubricated by axle / transmission oil, either simply by splashing, or by means of a lift pump which sprays certain parts of the transmission system, the oil returning to the reservoir by gravity.

[0003] Furthermore, in the context of vehicle electrification, there is a tendency to integrate the differential mechanism as close as possible to the electric machine, and preferably upstream of the reducer.

[0004] Some have already tried to install the differential at the heart of an electric motor rotor in the case of an electric motorization of a train or vehicle axle, as for example taught in documents EP0760549 or US 11394270. However, it proves problematic to be able to ensure effective lubrication of the differential mechanism in these configurations.

[0005] Moreover, in order to avoid using permanent magnets that consume rare earth natural resources, there is a tendency to use wound rotors, which must be excited from the stationary area through excitation friction rings, which occupies a substantial space at one end of the rotor shaft.

[0006] Furthermore, in the case where the differential is integrated on the axis of the electric machine in the rotor shaft or in the vicinity of the rotor shaft, it is necessary to pass one of the intermediate transmission shafts through the rotor shaft from one side to the other.

[0007] There therefore remains a need to propose a lubrication solution that combines objectives that are a priori contradictory.

[0008] It is in this context that the inventors sought to propose a lubrication system that was particularly ingenious with regard to other requirements and other functions.

[0009] To this end, an electromotor unit comprising is proposed: - an electromotive unit with an electric machine comprising a rotor shaft and a rotor mounted on the rotor shaft, and a differential mechanism, the rotor shaft being hollow tubular, - a first reduction gear, comprising a reduction gear housing, mounted adjacent to the electromotive unit, - a first intermediate shaft, hollow and fixed in rotation to one of the planetary gears of the differential mechanism, driving the first reduction gear, - at least one inlet of a forced oil flow, at a first entry point on the housing of the first reducer, the electro-motor unit comprising a conveying cannula extending from a first axial position in an axial area of ​​the first reducer to a central region of the differential mechanism, the conveying cannula passing through a central bore of the first intermediate shaft, a first end of the conveying cannula being arranged in an axial blind hole of an output member of the first reducer, so that the cannula allows the forced oil flow to be conveyed to the core of the differential mechanism.

[0010] Thanks to these arrangements, the conveying nozzle allows the forced oil flow to be directed towards the differential mechanism without this forced oil flow being dispersed into the first reduction gear. The conveying nozzle is a thin and lightweight tubular part that is inserted into the first intermediate shaft, without increasing the radial dimensions of the electric machine.

[0011] In the electromotor group, the differential is in a position which is not directly accessible to an external oil inlet point, in particular due to the presence of electrical equipment elements of the machine, sensor and excitation connection of the wound rotor.

[0012] Due to the position of the differential mechanism at the first end of the rotor shaft, the first intermediate shaft is here a short shaft compared to the other intermediate shaft which has a length close to the length of the rotor shaft.

[0013] According to one embodiment, the electromotor unit includes a lubrication system comprising an oil pump to supply the forced oil flow to the first point of entry.

[0014] According to an advantageous embodiment, the first reducer comprises a slow-speed gear fixed in rotation to the output member, the conveying cannula passing, directly or indirectly, through a hub of the large slow-speed gear and a hub of a first primary pinion forming the input of the first reducer.

[0015] Wherefore, the delivery cannula allows to pass several obstacles in the reducer, via the center, to deliver the oil to the heart of the differential mechanism.

[0016] The first intermediate shaft is received in the hub of the first primary pinion, with an interface with complementary splines at this point.

[0017] According to one embodiment, the delivery cannula includes a groove in which an O-ring bearing on an internal bearing provided in the outlet member is received.

[0018] The O-ring prevents oil from flowing directly into the splines coupling the output member to the slow-speed gear of the reducer. Thus, the passage provided by the internal area of ​​the cannula is the only direct outlet available from the axial blind hole formed in the output member.

[0019] It is the O-ring, by rubbing on the bearing of the output member, that causes the cannula to rotate at the output speed of the reducer.

[0020] According to one embodiment, the delivery cannula comprises at least two axial shimming fingers extending radially outwards, each equipped with an axial stop, and at least two centering walls.

[0021] According to one option, a radial projection is provided which combines the axial shim finger with its axial stop as well as the centering wall.

[0022] Advantageously, the number of centering walls can be three as well as the number of shims can be three.

[0023] According to one embodiment, the delivery cannula is manufactured by molding a synthetic polymer material. Complex shapes can be obtained and the cost of such a part is very moderate.

[0024] According to one embodiment, the cannula can be mounted in the first reducer during its preparation process.

[0025] According to one embodiment, the delivery cannula comprises at its second end a centering ogive.

[0026] According to one embodiment, the outer diameter of the centering ogive is slightly smaller than the inner diameter of the first intermediate shaft (to perform the insertion operation).

[0027] According to one embodiment, the outer diameter of the centering ogive is slightly smaller than the diameter of the central hole in the satellite carrier element of the differential mechanism (to limit backflow while minimizing friction at this point).

[0028] According to one embodiment, the internal diameter of the cannula is constant along its entire length. The internal surface is smooth and facilitates the passage of oil despite a small cross-section.

[0029] According to one embodiment, the planet carrier element comprises four branches and internal channels in each branch to bring oil to the bearings.

[0030] According to one embodiment, the oil path arrives on the shaft in a blind hole of an output member driven by the output of the first reducer, via radial bores.

[0031] According to one embodiment, the first entry point is at a distance from the axis, with an inlet channel preferably extending radially.

[0032] According to one embodiment, an additional O-ring is provided between the output member and the splined hub of the large slow gear.

[0033] This additional O-ring allows for the formation of an oil reservoir near the needle bearing and the coupling splines between the output member and the slow gear of the reducer.

[0034] According to one embodiment, from the first entry point on the side of the first reducer, the oil flow irrigates the entire electromotor unit including the second reducer.

[0035] According to an alternative solution, a second entry point is provided on the housing of the second reducer. In this case, there is a dual oil supply for the differential mechanism, thus providing redundancy.

[0036] According to one option, the second intermediate shaft is here a long shaft, due to the position of the differential mechanism at the first end of the rotor shaft.

[0037] According to one embodiment, the reducer is a gear cascade reducer, preferably with coaxial input and output. This provides an attractive form factor for easy integration of the electric motor unit into the vehicle architecture.

[0038] Optionally, each of the first and second reducers comprises a single reduction stage. This configuration proves to be simple, reliable, and inexpensive.

[0039] Optionally, the first and second reducers are identical, the second reducer being rotated 180° relative to the first reducer. This reduces industrial diversity.

[0040] The present invention also relates to a motor vehicle, comprising at least one electromotor unit as described above.

[0041] The vehicle in question may be an electric or hybrid vehicle.

[0042] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig. 1] illustrates a front view of an example of a motorized axle of a motor vehicle, in which the present invention is implemented; - [Fig.2] schematically represents in cross-section an electromotor unit according to the example of the axle in [Fig.1]; - [Fig.3] shows in cross-section the region of the electromotor unit where are located the oil inlet and the delivery cannula; - [Fig. 4] shows in more detail in cross-section the region of the group electric motor where the first end of the delivery cannula is located; - [Fig.5] represents a perspective view of an example of a delivery cannula; - [Fig.6] represents a cross-sectional view of the example of a delivery cannula from [Fig.5]; - [Fig.7] represents an exploded view, illustrating the elements involved in the differential device and also illustrating the assembly process of the device; - [Fig.8] illustrates an exploded local axial cross-sectional view representing part of the satellite carrier equipment.

[0043] 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.

[0044] Fig. 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.

[0045] In the illustrated example, this refers to an electric motor in a hybrid or pure electric vehicle.

[0046] 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 RI, R2 comprises an output pinion which drives the respective wheel 47 by means of a homokinetic transmission as known per se.

[0047] The reference numeral MEL designates the electric machine with a stator and a rotor. The electric machine operates as a motor or a generator depending on the driving conditions. The illustrated electric machine is radial flux, but the invention can also be applied to an axial flux electric machine.

[0048] The reference GEM designates the electromotor group which includes the electric machine MEL, the differential device DF, the left reducer RI (hereafter referred to as the first reducer) and the right reducer R2 (hereafter referred to as the second reducer).

[0049] The differential device DF can be integrated, at least in part, into the rotor shaft. The reference numeral UU designates an electromotive unit comprising the electric machine and the differential device DF.

[0050] Figures 2 and 3 illustrate, according to one possible embodiment, the position of the differential device DF in the electromotive unit UU relative to the electric machine. The output of the differential device drives, on the one hand, the short intermediate shaft Al (also called the first intermediate shaft) and, on the other hand, the long intermediate shaft A2 (also called the second intermediate shaft).

[0051] The MEL electric machine comprises a rotor shaft 1 and a rotor 9 mounted on the rotor shaft, the rotor shaft being hollow tubular.

[0052] The first reducer RI comprises a reducer housing CRI, mounted adjacent to the electromotive unit UU. The electric machine comprises a housing CM, composed here of three parts: a main housing CO in the shape of a sleeve around the stator, a first end housing Cl and a second end housing C2.

[0053] The electromotor group includes the short intermediate shaft Al, fixed in rotation to one of the planetary gears of the differential mechanism, in this case the second planetary gear 22.

[0054] The shaft Al is a hollow shaft, and fitted with grooves on its outer cylindrical wall, it drives the first reducer RI.

[0055] When the vehicle travels along a curved track, one of the intermediate drive shafts rotates faster than the other, as is known, causing each planetary gear to rotate on its own axis, a phenomenon known as differential slippage. It is therefore necessary to lubricate the components involved in the rotation of the planetary gear on its own axis.

[0056] The short intermediate shaft Al, once assembled, drives the first reducer RI via the first input pinion of the reducer, noted 31. The long intermediate shaft A2, once assembled, drives the second reducer R2 via the second input pinion of the reducer, noted 32.

[0057] The rotor shaft noted 1 is hollow (i.e. it has a tubular body) and is configured to house the long intermediate shaft A2. The rotor shaft 1 is integral with the rotor 9 of the machine.

[0058] The rotational locking of the rotor and the motor 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.

[0059] Turning to the figures, the rotor shaft 1 extends from a first axial end marked El to a second axial end marked E2 along a main axis marked Yl.

[0060] The rotor shaft 1 includes housings 18 formed in the tubular body at the first axial end El (see [Fig. 7]). These housings 18 are intended to receive and drive a planet carrier element 2 forming part of the differential mechanism denoted DF

[0061] The rotor shaft 1 has in its main part an outside diameter DI over a length denoted Ll, as seen in [Fig.5].

[0062] The rotor shaft 1 is mounted to rotate around Yl relative to the machine housing CM by means of two bearings B1 and B2.

[0063] The differential mechanism DF comprises 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.

[0064] 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 El, in the direction of E2.

[0065] The planet carrier element 2 is driven in rotation by the rotor shaft 1. The device of transmission includes four satellite gears (23,24,25,26) mounted for rotation on the satellite carrier 2.

[0066] The satellite carrier element 2 is cross-shaped with four identical arms. Each end includes an end trunnion 27 around which a satellite mounted at that location can rotate.

[0067] Each of the branches of the cross-shaped satellite carrier element extends along a local axis WR perpendicular to the main axis Yl. The satellite carrier element 2 includes internal channels 28 in each branch to bring oil to the bearings 5 ​​(see [Fig.8]).

[0068] The satellite carrier element 2 is made of steel, as are the satellites and the planetary.

[0069] The differential mechanism DF comprises a first planetary pinion 21 and a second planetary pinion 22.

[0070] Each planetary gear meshes with the satellite gears. The satellite gears do not mesh with each other.

[0071] The first planetary gear 21 is suitable for driving the short intermediate shaft A1. The second planetary gear 22 is suitable for driving the long intermediate shaft A2.

[0072] The number of satellite gears could be two. Thus, generally, the transmission device comprises at least two satellite gears.

[0073] A bearing 5 is provided interposed between each housing 18 and the satellite carrier 2. The bearing 5 allows the torque produced by the rotor to be taken up and transferred to the rotor shaft via the differential device.

[0074] With reference to figures 7 and 8, the bearing 5 may be mushroom-shaped. For example, each bearing 5 comprises a head 52 received in the respective opposite housing, and a bearing tube 51 around which a satellite is mounted.

[0075] Each of the bearing heads comprises two straight edges 55 parallel to the main axis Yl orthogonal to the local axis of the bearing tube.

[0076] Each of the bearings includes a front edge 56 which, once assembled, is flush with the free edge la of the shaft.

[0077] The head is convex outwards with an entry chamfer 57.

[0078] The curvature follows the general profile of the outer wall of the rotor shaft once the bearing is in place.

[0079] On the inner side, the head includes an annular flat 59 on which a washer rests. The annular flat surrounds the base of the bearing tube.

[0080] The bearing tube receives on the inner side a trunnion 27 of the planet carrier 2 received in an inner bearing 50. Furthermore, the bearing tube receives on the outer side, i.e. on its external cylindrical bearing surface 58, the inner bore 44 of the planet which can whirl at this point.

[0081] Each housing 18 comprises a semicircular housing base and two straight sides parallel to the Yl axis. The housing is open at an opening opposite the housing base. Each housing can be obtained very simply by a milling cutter.

[0082] The second planetary gear 22 bears, via a pressure washer, against a front face of an annular planetary thrust bearing 6. The planetary thrust bearing 6 includes a rear face which bears against a shoulder provided in the rotor shaft.

[0083] Advantageously, pressure washers (4,4') are provided on the back of the satellites and planetary gears.

[0084] Pressure washers are non-flat washers at rest. They exhibit a certain elasticity and can return to a flat shape under compressive stress. The pressure washers 4' on the back of the planetary gears contribute to compensating for axial play. The pressure washers 4 on the back of the satellite gears 45 contribute to compensating for transverse play. The pressure washers also contribute to self-centering of the drive shafts during rotation. Furthermore, this allows hysteresis to be eliminated when the direction of torque changes.

[0085] A differential cover, noted 7, is provided, inserted externally on the first axial end El of the rotor shaft 1. The differential cover 7 achieves the sandwich closure of the differential mechanism DF.

[0086] The differential cover 7 is formed as a metal ferrule with a material thickness between 2 mm and 4 mm.

[0087] The differential cover includes a covering skirt 70 delimited by a free circular border 74.

[0088] As can be seen in the figures, the differential cover 7 includes an axial opening 72 configured to allow a passage for the first intermediate shaft Al.

[0089] Furthermore, the rotor shaft 1 is configured to house the second intermediate shaft A2 up to an axial through opening at the second axial end E2 of the rotor shaft.

[0090] The differential cover 7 can be inserted by shrink fitting onto the rotor shaft 1.

[0091] The wound rotor is electrically activated via excitation tracks. The excitation tracks are arranged in an annular fashion at the second end E2 of the shaft opposite the position of the differential device.

[0092] The excitation tracks are conductive, for example made of copper alloy. Opposite each track, one or more friction pads (not shown) are provided which make contact with the track and are pushed towards the track by an elastic system.

[0093] The diameter of the long intermediate shaft A2 is chosen to be around 25 mm, for example, within a range of values ​​between 22 and 26 mm. It should be noted that, according to one option, the long intermediate shaft A2 has an axial lubrication passage 76 along its entire length.

[0094] It is noted that the transmission device is devoid of bearings inside the rotor shaft, which makes it possible to increase the compactness of the differential mechanism.

[0095] Bearing B1 is arranged to surround the second planetary gear 22, in the same axial position, for rotational guidance of the transmission device and, in particular, for guiding the rotor shaft. Bearing B1 is received in a bearing surface of the front housing Cl of the MEL machine.

[0096] Reducers

[0097] The first reducer RI includes a reducer housing marked CRI.

[0098] The first reducer RI comprises an input pinion 31, a high-speed gear 41, a low-speed gear 42, the low-speed gear comprising a toothed output hub, into which a toothed shaft 63 of the homokinetic transmission Tl to a wheel is inserted (cf [Fig.2]).

[0099] The input pinion 31 is guided in rotation by a bearing B3.

[0100] The shaft of the high-speed gear 41 is guided in rotation by a bearing B5 and a bearing B7.

[0101] The center distance separating the axis of the high-speed gear 41 from the main axis Y1 is denoted ER and is here between 100 mm and 130 mm. This is the same center distance that separates the axis of the high-speed gear 41 from the axis of the low-speed gear 42. Advantageously, the input and output of the first reducer are coaxial, on the axis Y1.

[0102] The slow gear 42 forms the output of the reducer, with a radially internal spline 42b which cooperates with a radially external spline 66.

[0103] The slow gear 42 includes a hub with an axial passage 42k.

[0104] 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 NI mounted on an inner bearing of the input pinion 31 (cf [Fig.4]).

[0105] The high-speed 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.

[0106] The slow gear 42 includes radially internal splines noted 42b for receiving the end 61 of the constant velocity joint Tl, in particular the splines 66.

[0107] The second reducer R2 includes an input pinion 32, a high-speed gear 41, a low-speed gear 42,1a low-speed gear comprising a toothed output hub, into which a toothed shaft end of the homokinetic transmission 62 is inserted towards the other wheel.

[0108] The second reducer R2 includes a reducer housing marked CR2.

[0109] 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. Advantageously, two identical reducers can be used, one being rotated 180° with respect to the other around an axis perpendicular to Yl.

[0110] It is noted that each reducer comprises five bearings (four ball bearings B3, B4, B5, B6, B7 and one needle bearing NI) to guide in rotation three rotating parts namely the input pinion, the high-speed gear and the low-speed gear.

[0111] Each gearbox housing is formed in two pieces as seen in [Fig.2].

[0112] Each CR1,CR2 gearbox housing is fixed to the CM machine housing at a end of the MEL electric machine.

[0113] 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.

[0114] Each reducer is a cascade gear reducer, preferably with coaxial input and output.

[0115] Each of the first and second reducers R1,R2 comprises a single reduction stage.

[0116] For example, the first and second reducers can be identical, the second reducer being rotated 180° relative to the first reducer.

[0117] Lubrication system

[0118] The electric motor unit includes a lubrication system comprising an oil pump PH to provide a forced oil flow FH.

[0119] The forced oil flow is brought to a first oil inlet point H1 on the housing CRI of the first reducer. A filter 79 is provided to filter the circulating oil flow.

[0120] The return of the oil to the oil reservoir (also called 'tank') is done by gravity.

[0121] Generally, the lubrication system includes oil passages and / or channels to convey the forced oil flow to the differential mechanism DF, the oil path passing through a central passage 75 of the first short intermediate shaft.

[0122] The first entry point H1 is at a distance from the axis, with an input channel F10, the input channel being provided in the housing of the first reducer RI.

[0123] The inlet channel F10 extends radially in the direction of the axis and opens into an annular volume G4 which acts as an intermediate buffer volume. The intermediate buffer volume G4 is delimited by a specific axial double-lip seal.

[0124] The annular volume G4 communicates with a second annular volume G5 of smaller diameter, located radially inside the buffer volume G4.

[0125] The path of the forced oil flow continues towards the axis through radial holes provided in the output member 61, which is driven by the output of the reducer. This output member 61, with a splined hub 66, forms part of the constant velocity transmission to the wheel 47.

[0126] There may be a single radial hole or two radial holes Fll diametrically opposed, or even three or more radial holes Fil.

[0127] The oil arrives in the axial zone in a blind hole cavity 68 formed in the trunnion 63 delimited by its front edge 65.

[0128] The path of the oil is schematically represented by the small black arrows in [Fig.4] and in [Fig.6].

[0129] The oil path then passes through a central passage 42k of the slow gear 42, then through a central passage 75 of the first short intermediate shaft Al.

[0130] According to one option, a conveying cannula 17 is provided which extends axially through the hub of the slow gear 42 of the reducer and the first short intermediate shaft Al through the axial passage 75.

[0131] The delivery cannula 17 extends from a first end EC1 to a second end EC2 over a total length denoted L17.

[0132] The axial conveying 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 Al.

[0133] To prevent excessive oil delivery into the first reducer, a groove 17a is provided at the first end of the delivery cannula, with an O-ring 175 received in the groove 17a. The forced oil flow is directed inside the delivery cannula 17. The O-ring 175 bears on an internal bearing 67 formed in the outlet member 61. The O-ring 175 and the delivery cannula 17 are driven in rotation by the inner bearing 67 of the outlet member 61.

[0134] The first end of the cannula rests on a shoulder 64 provided in the outlet member 61.

[0135] In the illustrated example, the second end of the cannula, designated 171, is received inside the satellite carrier element. This second end of 171 is formed as a centering ogive.

[0136] The outer diameter D71 of the cannula at the location of the second end 171 is slightly smaller than the diameter of the central hole 2H of the planet carrier element 2. This allows oil to flow backwards towards the first reducer and also avoids friction at this location due to the relative speed (the planet carrier is fast while the conveying cannula rotates slowly, being driven by the output pinion of the reducer via the O-ring 175).

[0137] On the outside of the output member 61 of the reducer, there is a lip seal noted 14, of known structure and functions, as well as a dust cover J15 (see [Fig.4]).

[0138] As seen in figures 5 and 6, the delivery cannula and a long, tubular piece extending along the main axis Yl.

[0139] In the illustrated example, the delivery cannula 17 comprises three radial projections distributed at 120° around the axis. Each radial projection combines an axial shimming finger and a centering wall.

[0140] More specifically, the delivery cannula 17 comprises three axial locking fingers 172 extending radially outwards. Each finger 172 is provided with an axial stop 179, which prevents the insertion movement of the cannula towards the second end, i.e., to the right in the diagrams. More precisely, the axial stop 179 comes to rest against a shoulder 78 of the slow-speed gear 42.

[0141] In the illustrated example, the conveying cannula 17 includes three centering walls 173. These walls 173 fit inside the inner bearing 42k of the hub of the slow-speed gear 42 to ensure centering on the axis Yl.

[0142] The number of radial projections could be greater than 3. The number of radial projections could be equal to 2.

[0143] The delivery cannula 17 delimits an internal channel 17c which has a constant diameter over its entire length, this diameter being noted D17i.

[0144] The outside diameter of the delivery cannula 17 in the current section is denoted D17e. D17e can be between 12mm and 16mm.

[0145] The end border of the first end EC1 is denoted 178.

[0146] In the illustrated example, the delivery cannula is manufactured by molding a synthetic polymer material.

[0147] To make it possible to insert the cannula into its position, the outer diameter D71 of the centering ogive 171 is slightly smaller than the inner diameter DA1 of the first intermediate shaft Al.

[0148] Optionally, as illustrated in figures 3 and 4, an additional O-ring 177 may be provided between output member 61 and splined hub of large slow gear 42.

[0149] 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 CRI.

[0150] The axial double-lip seal 11 is generally of revolution about the main axis Y1, and comprises a mounting portion and a working portion. The working portion comprises a first lip 15 configured to bear against a rotating bearing surface F15 and a second lip 16 configured to bear against a stationary bearing surface F16. The mounting portion comprises a rim received in a cylindrical bearing surface 140 provided in the housing CRI.

[0151] A passage 11b is provided to allow the oil to escape by overflow from the intermediate buffer volume G4 and flow into the second annular volume G5, which has a smaller diameter. The second annular volume G5, which has a smaller diameter, is connected to the radial holes Fil.

[0152] The passage 11b is arranged in an upper part of the joint 11, in the direction of the local vertical.

[0153] In [Fig.4] are shown the local oil reserves RH1, RH2 and RH3.

[0154] It is noted that there may be a second delivery cannula at the level of the second reducer R2, in particular when the latter is identical to the first reducer RI.

[0155] Lubrication of the second reducer

[0156] According to a first option, the oil conveying passages and / or channels bring part of the forced oil flow to the second reducer R2 via a central passage 76 of the second long intermediate shaft A2.

[0157] Optionally, as seen in [Fig.8], a small hole 2F may be provided which allows the oil to pass through the center of the satellite carrier to irrigate the passage provided inside the second long intermediate shaft.

[0158] According to a second option, a second entry point H2 is provided on the housing of the second reducer R2, supplied from the PH pump by an auxiliary circuit shown in dotted lines in [Fig.2].

[0159] It is advantageous to use two identical reducers (positions with rotations within 180°), and in this case the satellite carrier element can be supplied from both ends of the rotor shaft.

[0160] In this case, the second reducer has a designated delivery cannula similar to the one described previously and therefore not described again here.

[0161] Miscellaneous

[0162] Regarding the relative dimensions, we note that in an example of an embodiment, we have L1 / D1>2 where L1 is the axial length of the rotor shaft 1. The length of the electric machine is significant with regard to the access required for the forced oil flow to the heart of the machine.

[0163] The axial passages for the oil may have a diameter between 4 mm and 6 mm. This applies in particular to axial passages 75, 76 and, if a delivery cannula 17 is used, to the inner diameter of the cannula.

[0164] It is noted that the intermediate buffer volume G4 allows oil to be kept at this location directly and immediately usable from the first rotations in a start-up configuration, after a long stop or in the situation where the pump takes some time to deliver the forced oil flow to the inlet point Hl.

[0165] The flow of oil FH and the splash lubrication provide lubrication for the entire interior of the MEL electric machine and the entire interior of both gearboxes, including the N1 and N2 needle bearings and the various splines. The 42b and 66 splines and the NI needle bearing are lubricated.

[0166] It is noted that the electromotive unit UU integrates the differential function in a form factor that differs very little from a form factor of an electric machine alone for the same power characteristics.

[0167] According to a particular application example on a motor vehicle drive axle, DI < 62 mm for a motor torque to be passed up to the order of 800 Nm.

[0168] Moreover, the slippage is limited by the software functions.

[0169] According to an advantageous arrangement, the slippage of the differential device is limited by the general behavior of the system and in general and in particular by the intervention of software which makes it possible to drastically reduce the torque and therefore the rotational speed of the motor in the event that one of the wheels slips.

[0170] Regarding terminology, it should be noted that "planetary gears" can be called simply "planetary" and "satellite gears" can be called simply "satellites".

Claims

Demands

1. Powered electric drive (PED) comprising: - a power unit (PU) with an electric machine (EM) having a rotor shaft (1) and a rotor (9) mounted on the rotor shaft, and a differential mechanism (DM), the rotor shaft being hollow tubular; - a first reduction gear (RG), comprising a reduction gear housing (RG), mounted adjacent to the powered electric drive; - a first intermediate shaft (I1), hollow and rotationally fixed to one of the planetary gears of the differential mechanism, driving the first reduction gear; - at least one inlet of a forced oil flow (FH), at a first inlet point (H1) on the housing (RG) of the first reduction gear; the powered electric drive comprising a delivery nozzle (17) extending from a first axial position in an axial region of the first reduction gear (RG) to a central region of the differential mechanism (DM), the delivery nozzle (17) passing through a central bore (75) of the first intermediate tree,a first end (EC1) of the conveying cannula (17) being arranged in an axial blind hole (68) of an output member (61) of the first reducer, so that the cannula allows the forced oil flow to be conveyed to the heart of the differential mechanism.

2. Electromotor unit according to claim 1, wherein the first reducer comprises a slow-speed gear (42) rotationally fixed to the output member (61), the conveying cannula (17) passing, directly or indirectly, through a hub of the large slow-speed gear (42) and a hub of a first primary pinion (31) forming the input of the first reducer.

3. Electromotor unit according to any one of claims 1 to 2, wherein the conveying cannula (17) comprises a groove (17a) in which is received an O-ring (175) bearing on an internal bearing (67) provided in the output member (61).

4. Power unit according to any one of claims 1 to 3, wherein the conveying cannula (17) comprises at least two axial shimming fingers (172) extending radially outwards, each provided with an axial stop (179), and at least two centering walls (173).

5. Power unit according to any one of claims 1 to 4, wherein the delivery nozzle (17) is manufactured by molding a synthetic polymer material.

6. Power unit according to any one of claims 1 to 5, wherein the delivery cannula comprises at its second end (EC2) a centering ogive (171).

7. Electromotor unit according to claim 6, wherein the outside diameter (D71) of the centering ogive is slightly smaller than the inside diameter (DA1) of the first intermediate shaft (Al), and preferably slightly smaller than the diameter (D2H) of a central hole (2H) in the planet carrier element of the differential mechanism.

8. Electromotor unit according to any one of claims 1 to 7, wherein an additional O-ring (177) is provided between the output member (61) and a splined hub of the large slow-speed gear (42).

9. Power unit any one of claims 1 to 8, wherein the first reducer is a gear cascade reducer, preferably with coaxial input and output.

10. Motor vehicle, preferably electric or hybrid, comprising an electric motor unit (EMU) according to any one of claims 1 to 9.