Two-lip seal, having two axial lips, for a transmission member, lubrication system for a transmission member, and electromotive unit

Abstract

The invention relates to a two-lip seal (11), having two axial lips, for fitting to a transmission member to be lubricated, said two-lip seal comprising an attachment portion (12) and a working portion (13), the attachment portion comprising a tubular part (12a) received in a cylindrical bearing, the working portion comprising a first lip (15) configured to bear on an annular rotating bearing surface (F15) and a second lip (16) configured to bear on an annular stationary bearing surface (F16) belonging to a transmission member housing, the working portion being manufactured from a flexible organic material, wherein the two-lip seal having two axial lips contributes to delimiting a first annular oil chamber (G4) forming a local oil reserve (RH1), the second lip (16) comprising a recess (16a) forming a passage notch (11b) for the passage of oil. The invention also relates to a transmission member comprising such a seal.

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION: Two-lip axial seal for transmission component, lubrication system for transmission component and electromotor unit

[0003] The present invention relates to a lubrication system for a transmission component, notably using a two-lip axial seal. The transmission component may be part of an electrical motor unit of a motor vehicle, preferably electric or hybrid.

[0004] A transmission component 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.

[0005] The transmission component of interest here may be a reducer, in particular a gear cascade reducer.

[0006] Furthermore, in the context of vehicle electrification, when considering an axle driven by an electric machine, there is a tendency to integrate the differential mechanism as close as possible to the electric machine, and therefore upstream of two reducers (one for each wheel).

[0007]

[0005] In this context, it is necessary to be able to ensure effective lubrication of the differential mechanism even though it is not easily accessible from the outside.

[0008] One solution is to force a flow of oil, at least in part, along an axial path, and thus to circulate oil inside an axial channel of the intermediate transmission shafts and through the hollow rotor shaft.

[0009] Such an oil path is relatively long and consequently, during a prolonged stop of the vehicle, the oil path having gradually dried out, in particular depending on the posture of the vehicle in relation to the vertical, there is a significant amount of time for the lubrication system and its lift pump to be able to supply oil again to all the elements to be lubricated.

[0010] Therefore, there remains a need to offer a lubrication solution that meets the objectives of fast and efficient lubrication, to reach all the elements to be lubricated even after a prolonged stop of the vehicle.

[0011] To this end, a double-lip axial seal is proposed here, particularly for equipping a transmission component to be lubricated, generally rotating around an axis, comprising a fixing portion and a working portion, the fixing portion comprising a tubular part centered on the axis, the tubular part being suitable for being received in a first cylindrical bearing, the working portion comprising a first lip configured to bear in a first direction on an annular rotating surface and a second lip configured to bear, in a second direction opposite to the first direction, on an annular stationary surface belonging to a transmission component housing, the working portion being made from a flexible organic material, the double-lip axial seal contributing to delimiting a first annular oil chamber forming a local oil reservoir,in which the second lip includes a recess forming a notch for the passage of oil.

[0012]

[0010] Thanks to these arrangements, the first annular oil chamber forming a local oil reserve retains a quantity of oil over the long term which is mobilized without delay in the event of a prolonged stop of the vehicle.

[0013]

[0011] The working portion of the seal is sandwiched between two annular bearing surfaces, and slight compression allows for good efficiency and perfect operation of the two lips.

[0014] We note that the two lips are not in the same radial position, as will be detailed later, and this gives good elasticity to the working portion given its constitution in soft organic material, for example in synthetic elastomer or natural rubber.

[0015]

[0013] According to one embodiment, the recess extends over an angular sector between 5° and 55°, preferably over an angular sector between 8° and 25°, these values ​​not generally being limiting.

[0016] According to an advantageous embodiment, the axial double-lip seal has an outside diameter D11, the first lip has a free edge diameter D15 at rest, the second lip has a free edge diameter D16 at rest, and the seal is such that |D16 - D15| is between 0.1 x D11 and 0.2 x D11. The two lips are not in the same radial position; they are separated by a gap that remains small compared to the outside diameter.

[0017]

[0015] The notation | D16 - D15 | signifies the absolute value of the difference, indeed D15 can be smaller than D16 or conversely D15 can be larger than D16.

[0018]

[0016] This results in slightly offset annular support zones in a radial position, but not excessively so. This provides a good spring effect to the working portion, which possesses intrinsic elasticity.

[0019]

[0017] This joint configuration can operate in axial mode. This configuration allows for a small relative axial movement of the two annular bearing surfaces without loss of function or performance.

[0020]

[0018] According to one embodiment, the axial double lip seal has an axial dimension / thickness denoted E11 which can be between 0.03 x D11 and 0.05 x D11.

[0021]

[0019] This dimension represents a very small axial footprint. This promotes good compactness of the electromotor unit which includes the transmission element of interest here.

[0022]

[0020] According to one embodiment, the second lip comprises an end bead forming contact along the second direction, and the first lip comprises a section with a convex portion projecting towards the first direction to form a support contact along the first direction. The convex portion exhibits good efficiency and durability, with very low wear despite friction at this point due to the relative rotational movement.

[0023] The present invention also relates to a transmission element comprising a rotating output assembly mounted for rotation in a housing element, said rotating output assembly comprising a toothed output wheel and an output member, fixedly connected for rotation by complementary splines, the transmission member further comprising a double-lip axial seal as described above, the annular rotating bearing surface being arranged on an annular end area of ​​the hub of the toothed output wheel and the annular stationary bearing surface being arranged on an annular area of ​​the housing element, the first cylindrical bearing being provided in the housing element, the transmission member further comprising an auxiliary double-radial bearing surface, with an outer radial bearing surface bearing on a second cylindrical bearing surface provided in the housing element and an inner radial bearing surface bearing on the output member,so that a first annular oil chamber is formed, being delimited by the annular end area of ​​the output gear hub, the housing element, the axial double-lip seal and the radial double-span auxiliary seal, the transmission member being referenced with respect to a vertical direction and the mounting of the axial double-lip seal being such that the recess is located in an upper area of ​​the seal.

[0024] The recess is in the highest, highest position.

[0025] Note that the internal radial bearing rests on a shallow groove provided on the output member.

[0026] Thanks to the arrangements shown above, the two seals cooperate to form together an annular storage space over a large angular range suitable for storing a significant volume of oil.

[0027]

[0025] According to one embodiment, the auxiliary seal may include an anti-intrusion lip which has just rested in a groove of the second cylindrical bearing.

[0028] According to one embodiment, a lubrication oil flow path is planned which includes an oil injection point at a distance from the axis, a first pass, a transit through the first annular oil chamber, a passage through the recess, a transit through the second annular oil chamber, radial drillings in the outlet member, and an axial channel in a blind hole of the outlet member.

[0029] This oil flow path allows oil to be delivered to the center of the differential device.

[0030] According to one embodiment, the transmission element is formed as a reducer with the output gear corresponding to a large slow gear of the reducer, driven by a large fast gear, on the side of an input of the reducer.

[0031]

[0029] According to one embodiment, the input of the reducer and the output of the reducer are coaxial.

[0032]

[0030] According to one embodiment, the tubular part butts against a shoulder delimiting the first cylindrical bearing.

[0033] In one embodiment, the fixing portion comprises a metal reinforcement, preferably with an L-shaped cross-section, and the fixing portion includes a discoidal part transverse to the axis. The discoidal part is capable of being axially stopped by an axial positioning stop.

[0034]

[0032] According to one embodiment, the annular rotating bearing surface is machined and has a smooth surface where the first lip rubs against the toothed output wheel.

[0035] [0 This provides a good surface finish on the output gear hub. There is no wear or very little wear, and no oil leakage. In one embodiment, the axial double-lip seal is in a radial position outside the radial position of the radial double-seat auxiliary seal, and the axial double-lip seal is in an axial position inside the radial position of the radial double-seat auxiliary seal.

[0036] This relative positioning allows for an axial space and a radial space to form the oil storage volume.

[0037] The present invention also relates to a motor vehicle, comprising at least one transmission component as described above.

[0038] The vehicle in question may be an electric or hybrid vehicle.

[0039] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which:

[0040] - [Fig.1] illustrates a front view of a first example of a motorized axle of a motor vehicle, in which the present invention is implemented;

[0041] - [Fig.2] schematically represents in cross-section an electromotor group according to the first example of axle in figure 1, with an electric machine, a first reducer and a lubrication system;

[0042] - [Fig.3] schematically represents in partial section the axial zone of the first reducer, illustrating the path of the oil flow;

[0043] - [Fig.4] schematically represents in more detail in partial section the axial area of ​​the first reducer, illustrating the oil reservoir function provided by the axial double lip seal;

[0044] - [Fig.5] shows an example of an axial double-lip seal in perspective view;

[0045] - [Fig.6] shows in cross-section the example of a double axial lip seal from figure 5;

[0046] - [Fig.7] shows a detailed view of the lower area of ​​the axial double-lip seal and the radial double-span auxiliary seal

[0047] - [Fig.8] schematically represents an example of the general arrangement of the electromotor unit in relation to the vehicle reference frame and in particular in relation to the vertical.

[0048]

[0039] 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.

[0049] Regarding terminology, it should be noted that the terms "inside" and "outside" refer, when considering the radial direction, to an entity respectively closer to the axis or further from the axis.

[0041] Furthermore, it should be noted that the terms "inside" and "outside" refer, when considering the axial direction, to an entity respectively closer to the center of the transmission component or further from the center of the transmission component.

[0050]

[0042] Regarding terminology, it should be noted that "planetary gears" can be simply called "planetary" and "satellite gears" can be simply called "satellites".

[0051] 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.

[0052] In the illustrated example, this concerns an electric motor in a hybrid or pure electric vehicle.

[0045] 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 element that drives the respective wheel 47 through a constant velocity transmission T1, T2, as known per se.

[0053]

[0046] 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.

[0054] The reference GEM designates the electromotor group which includes the electric machine MEL, the differential device DF, the left reducer R1 (hereafter called first reducer) and the right reducer R2 (hereafter called second reducer).

[0055] The differential device DF can be integrated, at least partially, into the rotor shaft. The reference UU designates an electromotive unit that includes the electric machine and the differential device DF.

[0056]

[0049] 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 intermediate drive shafts B10 and B20 are each engaged in a planetary gear of the differential device DF.

[0057]

[0050] The MEL electric machine comprises a rotor shaft 1 and a rotor 9 mounted on the rotor shaft, the rotor shaft being hollow tubular.

[0058]

[0051] The first reducer R1 includes a reducer housing CR1, mounted adjacent to the electromotive unit UU. The electric machine includes a housing CM, composed here of three parts: a main housing C0 in the shape of a sleeve around the stator, a first end housing C1 and a second end housing C2.

[0059] [0 The short intermediate shaft B10 drives the first reducer R1 via the first input pinion of the reducer 31 equipped with splines 31k. The long intermediate shaft B20, once assembled, drives the second reducer R2 via the second input pinion of the reducer 32.

[0060] The rotor shaft marked 1 is hollow and is configured to house the long intermediate shaft B20. The rotor shaft 1 is integral with the rotor 9 of the machine.

[0061] The rotational coupling of the rotor and the drive shaft can be achieved by a shrink-fit process. In the illustrated example, grooves are provided in the rotor shaft which receive internal projections of the rotor's ferromagnetic plates. The grooves and projections cooperate through complementary shapes.

[0062]

[0055] The rotor shaft 1 is mounted to rotate around A1 relative to the machine housing CM by means of two bearings B1 and B2.

[0063] The differential mechanism DF includes a planet carrier element 2 driven by the rotor shaft 1. The transmission device includes four planet gears mounted for rotation on the planet carrier 2.

[0064]

[0057] The differential mechanism DF comprises a first planetary gear 21 and a second planetary gear 22. Each planetary gear meshes with the planetary gears. The planetary gears do not mesh with each other.

[0065] The first planetary gear 21 is suitable for driving the short intermediate shaft B10. The second planetary gear 22 is suitable for driving the long intermediate shaft B20. [0] A differential cover, labeled 7, is provided and inserted externally onto the axial end of the rotor shaft 1. The differential cover 7 provides a sandwich closure for the differential mechanism DF. The differential cover 7 can be inserted onto the rotor shaft 1 by press-fitting.

[0066] Furthermore, the rotor shaft 1 is configured to house the second intermediate shaft B20 up to an axial through opening at the second axial end of the rotor shaft.

[0067] Bearing B1 is arranged to surround the second planetary gear 22, in the same axial position, to guide the rotation of the transmission device and, in particular, to guide the rotor shaft. Bearing B1 is received in a bearing surface of the front housing C1 of the MEL machine.

[0068] Reducers

[0069] Looking at figures 2 to 4, the first reducer R1 includes a reducer housing labeled CR1.

[0070] The first reducer R1 includes 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 61 to a wheel is inserted (see figure 2).

[0071] The input pinion 31 is guided in rotation by a bearing B3. The shaft of the high-speed gear 41 is guided in rotation around the axis Y2 on both sides by a bearing B5 and a bearing B7.

[0072] Advantageously, the input and output of the first reducer are coaxial, centered on axis A1.

[0073] The slow gear 42 forms the output of the reducer, with a radially internal spline 42a which cooperates with a radially external spline 66.

[0074] The 42 slow gear includes a hub with an axial bore of 42k.

[0075] 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 figure 4).

[0076]

[0071] 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 low-speed gear 42, radially external.

[0077] The slow gear 42 includes radially internal splines, noted 42b, to receive the end of the constant velocity joint 61, in particular the splines 66.

[0078]

[0073] The second reducer R2 comprises 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 a toothed shaft end of the homokinetic transmission 62 is inserted towards the other wheel.

[0079] The second reducer R2 includes a reducer housing marked CR2.

[0080] The second reducer R2 is similar or even identical to the first reducer, and the description given for the first reducer applies to the second reducer R2. Advantageously, two identical reducers can be used, one being rotated 180° relative to the other around an axis perpendicular to A1.

[0081]

[0076] It is noted that each reducer includes five bearings (four ball bearings B3, B4, B5 B6 B7 and one needle bearing N 1) to guide in rotation three rotating parts namely the input pinion, the high-speed gear and the low-speed gear.

[0082]

[0077] Each reducer housing is formed in two pieces as can be seen in figure 2.

[0083] Each CR1, CR2 gearbox housing is fixed to the CM machine housing at one end of the MEL electric machine.

[0084]

[0079] 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.

[0085] Lubrication system

[0086] The electric motor unit includes a lubrication system comprising a PH oil pump to provide a forced FH oil flow.

[0087] The forced oil flow is directed to a first oil inlet point H1 on the housing CR1 of the first gearbox. A filter 79 is provided to filter the circulating oil flow.

[0088] The return of the oil to the oil reservoir (also called 'tank') is done by gravity.

[0089] In general, as seen in Figure 3, 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 B10.

[0090] 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 CR1 of the first reducer R1.

[0091]

[0086] 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 11 described below.

[0092] A specific axial double-lip seal 11 is provided in the first reducer R1. A similar specific axial double-lip seal 11 can also be provided in the second reducer R2, as illustrated in Figure 2.

[0093] In a generic way, the axial double lip seal will be described for use in any transmission component which may be a reducer, but which could also be another transmission component such as the gearbox.

[0094] Axial double-loop joint and auxiliary joint

[0095] As illustrated in Figure 5, the axial double-lip seal 11 is generally of revolution about the main axis A1. The axial double-lip seal 11 comprises a fixing portion 12 and a working portion 13.

[0096] The working portion 13 includes first lip 15 configured to bear along a first direction S1 on an annular rotating bearing F15 and a second lip 16 configured to bear, along a second direction S2 opposite to the first direction S1, on an annular stationary bearing F16 belonging to a transmission component housing here the housing CR1 of the first reducer R1.

[0097] [0 The working portion 13 is made from a flexible organic material. The radially inner free end of the working portion is denoted 11e. The working portion 13 is made, for example, of synthetic elastomer or natural rubber. It thus possesses good intrinsic elasticity.

[0098] The second lip 16 includes an end bead forming contact along the second direction S2.

[0099] The first lip 15 includes a section with a convex portion projecting in the first direction to form a bearing contact along that direction. The convex portion exhibits good efficiency and durability, with very low wear despite friction at this point due to the relative rotational movement.

[0100] The fixing portion 12 includes a tubular part 12a centered on the axis, the tubular part 12a being suitable to be received in a first cylindrical bearing P12.

[0101] The fixing portion 12 comprises a metal frame, preferably with an L-shaped cross-section, onto which the elastomeric material is bonded.

[0102] According to one option, the tubular part 12a is inserted axially into the housing and comes to rest on shoulder 71 which delimits first cylindrical bearing P12 on the side of the second direction S2.

[0103] The second lip 16 includes a recess 16a forming a passage notch 11b for oil passage, the recess preferably extending over an angular sector between 5° and 45°. For example, the recess extends over an angular sector between 8° and 20°.

[0104]

[0100] As seen in figure 6, the axial double-lip seal 11 has an outside diameter D11. The first lip 15 has a free edge diameter D15 at rest. The second lip 16 has a free edge diameter D16 at rest.

[0105] The geometry of the joint is such that |D16 - D15| is between 0.1 x D11 and 0.2 x D11, where |D16 - D15| means the absolute value of the difference.

[0106] The diameter D16-D15 is small compared to the diameter D11, and it should be noted that the first and second lips are not in the same radial position. The annular bearing areas F15 and F16 are thus slightly offset radially, but not excessively. This provides a good spring effect to the working portion, under the influence of the opposing pressure forces P5 and P6 shown in Figure 6.

[0107]

[0103] This configuration allows a small relative axial movement of the two annular bearing surfaces to be accepted, and / or a tolerance range for the positioning of the slow gear 42 relative to the housing to be managed, without loss of function or loss of performance.

[0108] The axial double lip seal 11 has an axial dimension / thickness noted E11 which is between 0.03 x D11 and 0.05 x D11.

[0109]

[0105] The axial double-lip seal 11 helps to define a first annular oil chamber G4 forming a first local oil reservoir denoted RH1

[0110]

[0106] According to an alternative option, the fixing portion 12 includes a discoidal part transverse to the axis capable of being stopped axially by an axial positioning stop.

[0111]

[0107] Furthermore, the transmission member also includes an auxiliary seal 14 with a double radial bearing surface. As can be seen in Figure 7, the auxiliary seal 14 comprises an outer radial bearing surface 14e bearing against a second cylindrical bearing P14 formed in the housing element and an inner radial bearing surface 14i bearing against the output member. [1] Furthermore, the auxiliary seal 14 includes an anti-intrusion lip, denoted 14f.

[0112]

[0109] In combination, a shallow groove marked 69 can be provided in the housing bearing (radially external bearing) to receive the anti-intrusion lip marked 14f of the auxiliary seal.

[0113] A passage 11b is provided to allow oil to escape by overflow from the intermediate buffer volume G4 and flow into the second, smaller-diameter annular volume G5. This second, smaller-diameter annular volume G5 communicates with the radial bores F11.

[0114] The intermediate buffer volume G4 contains a first oil reserve zone RH1. The second annular volume G5 contains a second oil reserve zone RH2.

[0115] There is also a third RH3 oil reserve zone which forms between the inner end 65 of the output member 61 and the opposite shoulder 77 in the hub of the slow gear 42.

[0116] Passage 11b is arranged in an upper part of joint 11, in the direction of the local vertical Z.

[0117] As seen in figure 7, the first annular oil chamber G4 is delimited by the annular end area 42t,42s of the output wheel hub with teeth 42, the housing element CR1, the axial double lip seal 11 and the radial double-bearing auxiliary seal 14.

[0118] The annular volume G4 communicates with a second annular volume G5 of smaller diameter, located radially inside the buffer volume G4, via passage 11b.

[0119] The axial double lip seal 11 is in a radial position outside the radial position of the radial double-span auxiliary seal 14.

[0120] In addition, the axial double lip seal 11 is in an axial position inside the radial position of the radial double-span auxiliary seal 14.

[0121] The forced oil flow continues towards the axis through radial holes F11 provided in the pinion 61 driven by the output of the reducer. This pinion 61, with a splined hub 66, forms part of the constant velocity transmission to the wheel 47.

[0122] There may be a single radial hole or two diametrically opposed F11 radial holes, or even three or more F11 radial holes.

[0123]

[0120] The oil arrives in the axial zone in a blind hole cavity 68 formed in the trunnion 63 delimited by its front edge 65.

[0124] The path of the oil is schematically represented by the small black arrows in figure 4.

[0125] 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 B10.

[0126]

[0123] 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 B10 by the axial passage 75.

[0127] The axial delivery cannula 17 carries the forced oil flow to the central orifice of the planet carrier element 2, passing as described above through the central passage 42k of the slow-speed gear 42 and the central passage 75 of the short shaft B10.

[0125] To prevent excessive oil delivery into the first reducer, a groove 170 is provided at the first end of the delivery cannula, with an O-ring 175 received in the groove 170. The forced oil flow is directed inside the delivery cannula 17.

[0128]

[0126] The cannula 17 is held in axial position by one or more stop fingers 172 visible in figure 4.

[0129]

[0127] The first end of the cannula rests on a shoulder 64 provided in the pinion 61.

[0130]

[0128] In the illustrated example, the second end of the cannula, marked 171, is received inside the planet carrier element. The outside diameter 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 backward towards the first reducer and also avoids friction at this location due to the relative speed (the planet carrier is fast while the delivery cannula rotates slowly, being driven by the output pinion of the reducer via the O-ring 175).

[0131]

[0129] On the outside of the output member 61 of the reducer, a dust cover J15 is provided (see figure 7), axially wedged against a shoulder 72 of the output member 61.

[0132]

[0130] 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

[0133] In addition, an auxiliary O-ring, marked 177, is provided, arranged in an internal annular groove at one end on the inside of the splines 42b of the slow gear 42.

[0134]

[0132] L6 L7

[0135]

[0133] Regarding the dimensions, the diameter D11 is in an example between 75 mm and 100 mm. The axial thickness denoted E11 is in an example between 5 mm and 8 mm.

[0136] Similarly, the axial thickness E14 is in an example between 5 mm and 8 mm.

[0137]

[0135] Considering Figure 7, the axial length denoted L6, which represents the overall axial distance between the two seals 11 and 14, can be between 12 mm and 20 mm. The axial length denoted L7, which represents the overall axial distance between the two seals and the dust cover J15, can be between 15 mm and 24 mm.

[0138]

[0136] Lubrication of the second reducer

[0139]

[0137] 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 of the second long intermediate shaft B20.

[0140] According to a second option, a second entry point H2 is planned on the housing of the second reducer R2, supplied from the PH pump by an auxiliary circuit represented by dotted lines in figure 2.

[0141]

[0139] 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.

[0142]

[0140] In this case, the second reducer also includes an axial double lip seal 11 and an auxiliary seal 14. In this case, the second reducer may include a conveying cannula similar to that described previously and therefore not described again here.

[0143]

[0142] Miscellaneous

[0144] Regarding the orientation in space of the electromotor group, figures 2 to 4 illustrate a first example where the reducers are located above the main axis Y1, in other words the reducers form upward-directed projections relative to the axis of the electromotor group.

[0145] According to another configuration schematically illustrated in Figure 8, in which the X-axis corresponds to the longitudinal direction of the vehicle, the Y-axis to the transverse direction of the vehicle, and the Z-axis (correction) to the vertical, the electric motor unit is arranged horizontally, that is, with the gearboxes projecting onto the horizontal plane relative to the main axis Y1. Y2 can be at the same level as Y1 or slightly higher. Naturally, in this configuration, the first oil inlet point H1 is located above the main axis (and therefore rotated approximately 90° compared to the configuration shown in Figures 2 to 4).

[0146]

[0145] The 'rotating output assembly' denoted E6 is an assembly comprising the toothed output wheel 42 and the output member 61. The assembly E6 is mounted for rotation in the housing element CR1.

[0147]

[0146] The axial passages for the oil may have a diameter between 3 mm and 6 mm. This applies in particular to the radial passages F10 and F11, the axial passages 75, 76 and, if a delivery cannula 17, the inner diameter of the cannula.

[0148] 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 H1 (respectively H2 where applicable).

[0149] The flow of FH oil and the splash lubrication provide complete lubrication to the interior of the MEL electric machine and the interior of both gearboxes, including the N1 and N2 needle bearings and the various splines. Splines 42b and 66, and needle bearing N1, are lubricated.

[0150]

[0149] It is noted that the electromotive unit UU integrates the differential function in a form factor which differs very little from a form factor of an electric machine alone for the same power characteristics.

Claims

DEMANDS 1. Axial double-lip seal (11), particularly for equipping a transmission component to be lubricated, generally of revolution about an axis (A1), comprising a fixing portion (12) and a working portion (13), the fixing portion (12) comprising a tubular part (12a) centered on the axis, the tubular part (12a) being suitable for being received in a first cylindrical bearing (P12), the working portion (13) comprising a first lip (15) configured to bear in a first direction (S1) on an annular rotating surface (F15) and a second lip (16) configured to bear, in a second direction (S2) opposite to the first direction, on an annular stationary surface (F16) belonging to a transmission component housing, the working portion (13) being made from a flexible organic material,the axial double-lip seal (11) contributing to defining a first annular oil chamber (G4) forming a local oil reservoir (RH1), in which the second lip (16) includes a recess (16a) forming a passage notch (11b) for oil passage.

2. Joint according to claim 1, having an outside diameter D11, and in which the first lip (15) has at rest a free edge diameter D15, the second lip (16) has at rest a free edge diameter D16, and the joint is such that | D16 - D15 | is between 0.1 x D11 and 0.2 x D11.

3. Joint according to claim 2, having an axial dimension denoted E11 which is between 0.03 x D11 and 0.05 x D11.

4. Joint according to any one of claims 1 to 3, wherein the second lip (16) comprises an end bead forming contact along the second direction (S2), and the first lip (15) comprises a section with a convex portion projecting towards the first direction (S1) to form a support contact along the first direction.

5. Transmission member comprising a rotating output assembly (E6) rotatably mounted in a housing element (CR1), said rotating output assembly comprising a toothed output wheel (42) and an output member (61), rotationally connected by complementary splines (42b, 66), the transmission member further comprising an axial double-lip seal (11) according to any one of claims 1 to 4, the annular rotating bearing surface (F15) being arranged on an annular end area (42s) of the hub of the toothed output wheel and the annular stationary bearing surface (F16) being arranged on an annular area of ​​the housing element (CR1), the first cylindrical bearing (P12) being provided in the housing element (CR1), the transmission member further comprising an auxiliary seal (14) with a double radial bearing surface,with an outer radial bearing surface (14e) supported on a second cylindrical bearing (P14) formed in the housing element and an inner radial bearing surface (14i) supported on the output member, so that a first annular oil chamber (G4) is formed, being delimited by the annular end area (42t,42s) of the hub of the toothed output wheel, the housing element (CR1), axial double-lip seal (11) and the auxiliary seal (14) with double radial bearing surface, the transmission element being referenced with respect to a vertical direction (Z) and the mounting of the axial double lip seal being such that the recess is located in an upper area of ​​the seal.

6. Transmission member according to claim 5, wherein a lubricating oil flow path includes an oil injection point (H1) at a distance from the axis (A1), a first passage (F10), a passage through the first annular oil chamber (G4), a passage through the recess (16a), a passage through the second annular oil chamber (G5), radial bores (F11) in the output member (61), and an axial channel in a blind hole (68) of the output member (61).

7. Transmission element according to any one of claims 5 to 6, formed as a reducer (R1) with the output gear corresponding to a large slow gear (42) of the reducer, driven by a large fast gear (41) on the side of an input of the reducer, the reducer preferably having a coaxial input and output.

8. Transmission element according to any one of claims 5 to 7, wherein the annular rotating bearing surface (F15) is machined and has a smooth surface, 9. Transmission member according to any one of claims 5 to 8, wherein the axial double lip seal (11) is in a radial position outside the radial position of the radial double-span auxiliary seal (14) and the axial double lip seal (11) is in an axial position inside the radial position of the radial double-span auxiliary seal (14).

10. Motor vehicle, preferably electric or hybrid, comprising a transmission component according to any one of claims 1 to 9.

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