Epicyclic gear transmission mechanism and associated drive assembly

Abstract

A transmission mechanism (18) comprises a drive shaft (20), a driven member (12) rotating about a rotational axis (32), and an epicyclic gear train (22) comprising a first input member (24), a second input member (26), and an output member (28) rotationally fixed to the rotating driven member (12). The transmission mechanism (18) comprises a first kinematic linkage (L1) with a first speed ratio other than 1 between the drive shaft (20) and the first input member (24) of the epicyclic gear train (22), and a second kinematic linkage (L2) between the drive shaft (20) and the second input member (26) of the epicyclic gear train (22) with a second speed ratio other than 1 and different from the first speed ratio. (Shorthand figure: 1)

Description

Title of the invention: Epicyclic gear transmission mechanism and associated drive assembly TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a transmission mechanism, intended for example for driving a motorized vehicle, for example a motor vehicle, a motorcycle, a motorized personal mobility device (PMD), a vehicle for transporting persons with reduced mobility or an autonomous vehicle, or a piece of equipment, for example a power take-off of a construction vehicle or an agricultural vehicle. It also relates to a drive assembly incorporating such a transmission mechanism. PREVIOUS STATE OF THE ART

[0002] Document EP3630521 describes a transmission mechanism comprising: a drive shaft driven by an electric motor, a driven member consisting of a differential rotating about an axis of rotation coaxial with the drive shaft, a main epicyclic gear train comprising a first input member, a second input member and an output member fixed to the rotating driven member; and a connection between the drive shaft and the first input member of the main epicyclic gear train with a speed ratio of 1. The drive of the second input member of the main epicyclic gear train is achieved via at least one idler shaft parallel to the drive shaft, in a very bulky arrangement in the axial direction, and not allowing a high speed ratio between the drive shaft and the driven member.Without sufficient gear reduction in the transmission mechanism, the electric motor must then be sized to deliver high torque, which is undesirable. Description of the invention

[0003] The invention aims to remedy the drawbacks of the prior art and to propose a compact transmission mechanism which makes it possible to obtain, at the output of the mechanism, a high torque and a low drive speed.

[0004] To this end, according to a first aspect of the invention, a transmission mechanism is proposed comprising a drive shaft, a driven member rotating about an axis of rotation, and an epicyclic gear train comprising a first input member, a second input member, and an output member fixed in rotation to the rotating driven member. The transmission mechanism comprises a first kinematic linkage with a first speed ratio other than 1 between the drive shaft and the first input member of the epicyclic gear train, and a second kinematic linkage between the drive shaft and the second input element of the epicyclic gear train with a second speed ratio different from 1 and different from the first speed ratio.

[0005] This arrangement has the advantage of imposing two different output speeds on the kinematic links from a single input speed generated by a single drive shaft, thus saving space for the positioning of an input component fixed to the drive shaft, for example, an electric machine. This arrangement also makes it possible to offer a range of transmission mechanisms with speed ratios varying over a very wide range, depending on the size of the planetary gears of the epicyclic gear train and the choice of input components of the epicyclic gear train, while maintaining a similar overall size.

[0006] The first gear ratio and the second gear ratio may have the same sign, positive or negative, or opposite signs.

[0007] In one embodiment, the drive shaft is parallel to an axis of rotation of the epicyclic gear train. In another embodiment, the epicyclic gear train and the driven member are coaxial. Alternatively, the axis of rotation of the epicyclic gear train is parallel to, and distinct from, the axis of rotation of the driven member.

[0008] A first kinematic link connects the drive shaft to the output member. In one embodiment, this first kinematic link may include: - a driving gear fixed to the drive shaft meshing with a driven gear fixed to the first input member of the epicyclic gear train; or - a drive wheel fixed to the drive shaft driving a chain driving a driven wheel fixed to the first input component of the epicyclic gear train; or - a drive wheel attached to the drive shaft driving a belt driving a driven wheel attached to the first input element of the epicyclic train. Similarly, a second kinematic linkage, different from the first kinematic linkage, connects the drive shaft to the output component, and may include: - a second driving gear fixed to the drive shaft meshing with a second driven gear fixed to the second input component of the epicyclic gear train; or - a second drive wheel fixed to the drive shaft driving a belt driving a driven wheel fixed to the first input component of the epicyclic gear train; or - a second drive wheel attached to the drive shaft driving a belt driving a driven wheel attached to the first input element of the epicyclic train.

[0009] The proposed mechanism makes it possible to obtain high transmission ratios. Next In one embodiment, the mechanism has a speed ratio between the driving shaft and the rotating receiving member in a ratio which, in absolute value, is greater than 15, for example greater than 50, preferably greater than 100. Higher ratios can be obtained, for example greater than 200, without generating any particular geometric constraints.

[0010] According to various embodiments, the epicyclic train can have in particular three configurations which each induce a set of conditions to be satisfied.

[0011] According to a first embodiment, the first input member of the epicyclic gear train is an inner planetary gear, the output member of the epicyclic gear train is a ring gear, and the second input member of the epicyclic gear train is a planet carrier carrying planetary gears that mesh with both the inner planetary gear and the ring gear. High speed ratios can be obtained, in particular, by following, preferably cumulatively, the following requirements: - the ratio of the number of teeth on the ring gear to the number of teeth on the inner planetary gear is between 1.5 and 3, and / or - the first kinematic link and the second kinematic link are such that the first velocity ratio and the second velocity ratio have the same sign. In a particularly efficient embodiment, the first kinematic linkage comprises at least one driving gear fixed to the drive shaft meshing with a driven gear fixed to the first input member of the epicyclic gear train, and the second kinematic linkage comprises at least one second driving gear fixed to the drive shaft meshing with a second driven gear fixed to the second input member of the epicyclic gear train. In this embodiment, the second driven gear has a pitch diameter larger than the first driven gear, the first driving gear has a pitch diameter larger than the second driving gear, the second driven gear has a pitch diameter larger than the second driving gear, the first driven gear has a pitch diameter larger than the first driving gear, and the ring gear has a diameter larger than the inner planet gear.

[0012] According to another embodiment, the first input member of the epicyclic gear train is a planet carrier, the second input member of the epicyclic gear train is a ring gear, and the output member of the epicyclic gear train is an inner planet gear, the planet carrier carrying planets that mesh with both the inner planet gear and the ring gear. High speed ratios can be obtained, in particular, by following, preferably cumulatively, the following requirements: • the ratio of the number of teeth on the ring gear to the number of teeth on the inner planet gear is between 1.5 and 9, and / or • the first kinematic link and the second kinematic link are such that the first velocity ratio and the second velocity ratio have the same sign. According to a particularly efficient embodiment, the first kinematic link comprises at least one driving gear fixed to the driving shaft meshing with a driven gear fixed to the first input element of the epicyclic train and the second kinematic link comprises at least one second driving gear fixed to the driving shaft meshing with a second driven gear fixed to the second input element of the epicyclic train.In this embodiment, the first driven gear has a pitch diameter greater than the second driven gear, the second driven gear has a pitch diameter greater than the first driven gear, the first driven gear has a pitch diameter greater than the first driven gear, the second driven gear has a pitch diameter greater than the second driven gear, and the ring gear has a pitch diameter greater than the inner planet gear.

[0013] According to another embodiment, the first input member of the epicyclic gear train is an inner planet gear, the second input member of the epicyclic gear train is a ring gear, and the output member of the epicyclic gear train is a planet carrier, the planet carrier carrying planets that mesh with both the inner planet gear and the ring gear. High speed ratios can be obtained, in particular, by following, preferably cumulatively, the following requirements: • the ratio of the number of teeth on the ring gear to the number of teeth on the inner planet gear is between 1.5 and 4 and / or • the first kinematic link and the second kinematic link are such that the first velocity ratio and the second velocity ratio have opposite signs. This difference in sign can be achieved, in particular for kinematic links made by gears, by having an even number of gears in one kinematic link and an odd number in the other. For kinematic links made by belts or chains, the reversal can be achieved by crossing one of the belts or chains. According to a particularly efficient embodiment, the first kinematic link has at least one driving gear fixed to the drive shaft meshing with an intermediate gear, which meshes with a driven gear fixed to the first input element of the epicyclic gear train, and the second kinematic link has at least one second driving gear fixed to the drive shaft meshing with a second driven gear fixed to the second input element of the epicyclic gear train.In this embodiment, the second receiving gear has a pitch diameter greater than the . first driven gear, first driven gear has a pitch diameter greater than second driven gear, second driven gear has a pitch diameter greater than second driven gear, first driven gear has a pitch diameter greater than first driven gear and the ring gear has a pitch diameter greater than the inner planetary gear.

[0014] According to a preferred embodiment, to increase the compactness of the mechanism, the rotating receiving member is an output differential driving two output shafts coaxial with the main axis of rotation of the epicyclic gear train, one of the two output shafts passing through the epicyclic gear train. Alternatively, the rotating receiving member is an output differential driving two output shafts parallel with the main axis of rotation of the epicyclic gear train.

[0015] In one embodiment, the rotating receiving member is a shaft driving a wheel. In another embodiment, the rotating receiving member is a power take-off.

[0016] Furthermore, the invention also relates to a drive assembly comprising a rotating electric machine and a transmission mechanism, the rotating electric machine being coaxial with the drive shaft and positioned axially on the same side of the input member of the epicyclic gear train as the driven member. The drive assembly may be a drive assembly for driving a power take-off or a load, or a propulsion assembly for a motor vehicle. BRIEF DESCRIPTION OF THE FIGURES

[0017] Other features and advantages of the invention will become apparent from the following description, with reference to the attached figures.

[0018] [Fig.1] Fig.1 illustrates a vehicle drive train comprising a propulsion assembly and a transmission mechanism according to a first embodiment of the invention.

[0019] [Fig.2] Fig.2 illustrates a vehicle drive train comprising a propulsion assembly and a transmission mechanism according to a second embodiment of the invention.

[0020] [Fig.3] Fig.3 illustrates a vehicle drive train comprising a propulsion assembly and a transmission mechanism according to a third embodiment of the invention.

[0021] [Fig.4] Fig.4 illustrates a vehicle drive train comprising a propulsion assembly and a transmission mechanism according to a fourth embodiment of the invention.

[0022] [Fig. 5] Fig. 5 illustrates a vehicle drive train comprising a set of propulsion and a transmission mechanism according to a fifth embodiment of the invention.

[0023] [Fig.6] Fig.6 illustrates a vehicle drive train comprising a propulsion assembly and a transmission mechanism according to a sixth embodiment of the invention.

[0024] For clarity, functionally identical or similar elements are identified by identical reference numerals throughout the figures, DETAILED description of embodiments

[0025] Figure 1 illustrates a drive train 10 of a vehicle intended more particularly, although not exclusively, for a soft mobility vehicle, comprising a receiving organ 12 driven by a drive assembly 14, which in this case is a propulsion assembly.

[0026] This propulsion assembly 14 comprises a rotating electric machine 16 and a transmission mechanism 18 kinematically linking the electric machine 16 to the driven element 12 of the vehicle. The transmission mechanism 18 comprises a drive shaft 20 driven directly by the electric machine 16, the drive shaft 20 and the electric machine 16 being coaxial.

[0027] The transmission mechanism 18 has a speed reduction function. For this purpose, the transmission mechanism 18 is composed of an epicyclic gear train 22, which includes a first input member 24, a second input member 26 and an output member 28. In the embodiment of [Fig. 1], the first input member 24 of the epicyclic gear train 22 is a planetary gear, the output member 28 of the epicyclic gear train 22 is a ring gear and the second input member 26 of the epicyclic gear train 22 is a planet carrier kinematically linked to a row of planet gears 221 meshing with the first input member 24 and the output member 28 of the epicyclic gear train 22.

[0028] A first kinematic linkage L1 connects the drive shaft 20 to the first input element 24 of the epicyclic gear train 22. The first kinematic linkage L1 is composed of a rotating input element, here a first driving gear 21 fixed in rotation to the drive shaft 20 and meshing with a rotating output element, here a first driven gear 23. The first driven gear 23 of the first kinematic linkage L1 is fixed in rotation to the first input element 24 of the epicyclic gear train 22.

[0029] A second kinematic link L2 connects the drive shaft 20 to the second input element 26 of the epicyclic gear train 22. It consists of a second rotating input element, here a second driving gear 25 fixed in rotation to the drive shaft 20 and meshing with a rotating output element, here a second driven gear 27. The second driven gear 27 is fixed in rotation to the second input element 26 of the epicyclic gear train 22.

[0030] The axial distance between the first kinematic link L1 and the electric machine 16 is preferably greater than the axial distance between the second kinematic link L2 and the electric machine 16.

[0031] The first kinematic link L1 allows a first reduction speed ratio to be achieved between the drive shaft 20 and the first input element 24 of the epicyclic train 22. The second kinematic link L2 allows a second reduction speed ratio to be achieved between the drive shaft 20 and the second input element 26 of the epicyclic train 22, which is different from the first speed ratio.

[0032] In the embodiment of [Fig. 1], the transmission mechanism is characterized in that: • the ratio of the number of teeth of the output member 28 of the epicycloidal train 22 to the number of teeth of the first input member 24 of the epicycloidal train 22 is between 1.5 and 3; • the second receiving gear 27 has a pitch diameter greater than the first receiving gear 23; • the first driving gear 21 has a pitch diameter greater than the second driving gear 25; • the second receiving gear 27 has a pitch diameter greater than the second driving gear 25; • the first receiving gear 23 has a pitch diameter greater than the first driving gear 21; • the output member 28 of the epicyclic train 22 has a diameter greater than the input member 24 of the epicyclic train 22.

[0033] In practice, the speed ratio between the drive shaft 20 and the receiving member 12 of the transmission mechanism 18 is within a ratio greater than 15, preferably greater than 50, preferably greater than 100.

[0034] According to other variants not illustrated, one and / or the other of the first and second kinematic links L1 and L2 may be composed of a driving wheel fixed to the driving shaft 20 driving a chain driving a driven wheel fixed to the first input element 24 of the epicyclic train 22; or of a driving wheel fixed to the driving shaft 20 driving a belt driving a driven wheel fixed to the first input element 24 of the epicyclic train 22.

[0035] The output member 28 of the epicyclic gear train 22 is rotationally fixed to the receiving member 12 of the vehicle. In the embodiment of [Fig. 1], the receiving member 12 is a wheel 11 which has a rotation axis 32 coaxial with a main rotation axis 30 of the epicyclic gear train 22.

[0036] The main axis of rotation 30 of the epicyclic gear train 22 and the drive shaft 20 of the transmission mechanism 18 are parallel but distinct, coplanar or pre- non-coplanar ferrules.

[0037] Figure 1 shows several rotating guide bearings to ensure good transmission of forces, in particular torque forces: a first guide bearing 29 at the input of the electric machine 16, a guide bearing 31 at the output of the electric machine 16, a guide bearing 33 at the input of the first kinematic link Ll, a guide bearing 35 at the output of the first kinematic link Ll, a guide bearing 37 at the output of the output member 28 of the epi-cycloidal train 22, a guide bearing 39 at the input of the receiving member 12 and a guide bearing 41 at the output of the receiving member 12.

[0038] A toothed wheel 19 fixed in rotation to the motor shaft 20 and located for example axially at a distance less than the electric machine 16 than the second kinematic link L2 can allow to link the motor shaft 20 to a parking brake (not shown).

[0039] The embodiment shown in [Fig. 2] differs from the previous one in that the second input member 26 of the epicyclic gear train 22 is a toothed ring, the output member 28 of the epicyclic gear train 22 is a planetary gear, and the first input member 24 of the epicyclic gear train 22 is a planet carrier kinematically linked to a row of planets 221 meshing with the second input member 26 and with the output member 28 of the epicyclic gear train 22. The toothed ring rotates about the main axis of rotation 30 of the epicyclic gear train 22. Rotating guide bearings 43 guide the toothed ring.

[0040] In the embodiment of [Fig.2], the transmission mechanism is characterized in that: • the ratio of the number of teeth of the output member 28 of the epicycloidal train 22 to the number of teeth of the first input member 24 of the epicycloidal train 22 is between 1.5 and 9; • the first receiving gear 23 has a pitch diameter greater than the second receiving gear 27; • the second driving gear 25 has a pitch diameter greater than the first driving gear 21; • the first receiving gear 23 has a pitch diameter greater than the first driving gear 21; • the second receiving gear 27 has a pitch diameter greater than the second driving gear 25; • the output member 28 of the epicyclic train 22 has a diameter greater than the input member 24 of the epicyclic train 22.

[0041] The embodiment shown in [Fig. 3] differs from the previous one in that the first input member 24 of the epicyclic gear train 22 is a planetary gear, the The second input member 26 is a toothed ring and the rotating output member 28 is a planet carrier kinematically linked to a row of planets 221 meshing with the first input member 24 and with the second input member 26 of the epi-cycloidal train 22.

[0042] In this embodiment, the first kinematic link L1 is formed of a first driving gear 21, meshing with an intermediate gear 17 meshing with a first receiving gear 23.

[0043] In the embodiment of [Fig.3], the transmission mechanism is characterized in that: • the ratio of the number of teeth of the output member 28 of the epicycloidal train 22 to the number of teeth of the first input member 24 of the epicycloidal train 22 is between 1.5 and 4; • the second receiving gear 27 has a pitch diameter greater than the first receiving gear 23; • the first driving gear 21 has a pitch diameter greater than the second driving gear 25; • the second receiving gear 27 has a pitch diameter greater than the second driving gear 25; • the first receiving gear 23 has a pitch diameter greater than the first driving gear 21; • the output member 28 of the epicyclic train 22 has a diameter greater than the input member 24 of the epicyclic train 22.

[0044] The embodiment shown in [Fig. 4] differs from that shown in [Fig. 1] in that the receiving member 12 of the transmission mechanism 18 is an output differential 34 driving two output half-shafts 36 and 38 coaxial with the main axis of rotation 30 of the epicyclic gear train, one half-shaft 36 passing through the epicyclic gear train 22. In this configuration, the main axis of rotation 30 of the epicyclic gear train 22 is a hollow shaft. A first guide bearing 45 is mounted on the half-shaft 36 and a second guide bearing 47 is mounted on the half-shaft 38.

[0045] A similar configuration with a receiving organ 12 of the transmission mechanism 18 and an output differential 34 can be adapted from the mechanisms of figures 2 or 3.

[0046] The embodiment shown in [Fig. 5] differs from that shown in [Fig. 2] in that the axis of rotation 32 of the output wheel 11 is parallel but not coincident with the main axis of rotation 30 of the epicyclic gear train 22, a driving gear 40 fixed in rotation to the output member 24 of the epicyclic gear train 22 meshing with a driven gear 42 fixed in rotation to the axis of rotation of the wheel 11. In this embodiment, the transmission mechanism 18 comprises a guide bearing 49 at the output of the main rotation axis 30 of the epicyclic gear train 22.

[0047] A similar configuration with a rotation axis 32 of the output member parallel and not coincident with the main rotation axis 30 of the epicyclic train can be adopted to adapt the embodiments of figures 1 or 3.

[0048] The embodiment shown in [Fig. 6] differs from that shown in [Fig. 4] in that the two output half-shafts 36 and 38 of the output differential 34 are parallel and equidistant with the main axis of rotation 30 of the epicyclic gear train 22. A drive gear 48, rotationally fixed to the main axis 30 of the epicyclic gear train 22, meshes with an input member 50 of the output differential 34. In this embodiment, the transmission mechanism 18 comprises a guide bearing 49 at the output of the main axis of rotation 30 of the epicyclic gear train 22, a guide bearing 51 at the end of the differential surrounding the output half-shaft 36, and a guide bearing 53 at the end of the differential surrounding the output half-shaft 38.

[0049] Similar configurations can be deduced from the mechanisms of [Fig.2] or 3.

[0050] Naturally, the examples shown in the figures and discussed above are given by way of illustration only and are not intended to be limiting. It is explicitly intended that the different embodiments illustrated may be combined to propose others.

Claims

Demands

1. A drive assembly (14) for a vehicle comprising a rotating electrical machine (16), and a transmission mechanism (18) kinematically linking the electrical machine (16) to a receiving element (12) of the vehicle, said transmission mechanism (18) comprising: - a drive shaft (20) driven directly by the electric machine (16), the drive shaft (20) and the electric machine (16) being coaxial, - the receiving organ (12) rotating around an axis of rotation (32), - an epicycloidal train (22) comprising a first input organ (24), a second input organ (26) and an output organ (28) fixed in rotation to the rotating receiving organ (12); in which the transmission mechanism (18) comprises a first kinematic link (L1) with a first speed ratio different from 1 between the drive shaft (20) and the first input member (24) of the epicyclic train (22), and a second kinematic link (L2) between the drive shaft (20) and the second input member (26) of the epicyclic train (22) with a second speed ratio different from 1 and different from the first speed ratio, characterized in that the rotating receiving member (12) is an output differential driving two output shafts coaxial with the main axis of rotation (30) of the epicyclic train (22), one of the two output shafts passing through the epicyclic train (22).

2. Drive assembly (14) according to claim 1, characterized in that the first kinematic linkage (L1) comprises at least: - a driving gear (21) fixed to the driving shaft (20) meshing with a driven gear (23) fixed to the first input element (24) of the epicyclic gear train (22); or - a driving gear fixed to the driving shaft (20) driving a chain driving a driven gear fixed to the first input element of the epicyclic gear train; or - a drive wheel fixed to the drive shaft (20) driving a belt driving a driven wheel fixed to the first input component of the epicyclic gear train.

3. A drive assembly (14) according to any one of the preceding claims, characterized in that the second kinematic link (L2) comprises at least: - a second driving gear (25) fixed to the driving shaft (20) meshing with a second driven gear (27) fixed to the second input member (26) of the epicyclic gear train (22); or - a second driving gear fixed to the driving shaft (20) by driving a belt driving a driven gear fixed to the first input member of the epicyclic gear train; or - a second driving gear fixed to the driving shaft (20) by driving a belt driving a driven gear fixed to the first input member of the epicyclic gear train.

4. Drive assembly (14) according to any one of the preceding claims, characterized in that the mechanism (18) has a speed ratio between the drive shaft (20) and the rotating receiving member (12) in a ratio which, in absolute value, is greater than 15, for example greater than 50, preferably greater than 100.

5. Drive assembly (14) according to any one of the preceding claims, characterized in that the first input member (24) of the epicyclic train (22) is an inner planetary gear, the output member (28) of the epicyclic train (22) is a toothed ring and the second input member (26) of the epicyclic train (22) is a planet carrier carrying planetary gears (221) meshing both with the inner planetary gear and with the toothed ring.

6. Drive assembly (14) according to claim 5, characterized in that: - the ratio of the number of teeth of the ring gear to the number of teeth of the inner planetary gear is between 1.5 and 3, and / or - the first kinematic linkage (L1) and the second kinematic linkage (L2) being such that the first speed ratio and the second gear ratio has the same sign.

7. Drive assembly (14) according to claim 5 or claim 6, characterized in that the first kinematic linkage (L1) comprises at least one driving gear (21) integral with the driving shaft (20) meshing with a driven gear (23) integral with the first input member of the epicyclic gear train (22), the second kinematic linkage (L2) comprises at least one second driving gear (25) integral with the driving shaft (20) meshing with a second driven gear (27) integral with the second input member (26) of the epicyclic gear train (22), and in that: - the second driven gear (27) has a pitch diameter greater than the first driven gear (23); - the first driving gear (21) has a pitch diameter greater than the second driving gear (25); - the second receiving gear (27) has a pitch diameter greater than the second driving gear (25);- the first receiving gear (23) has a pitch diameter greater than the first driving gear (21); and - the ring gear has a diameter greater than the inner planet gear.

8. A drive assembly (14) according to any one of claims 1 to 4, characterized in that the first input member (24) of the epicyclic gear train (22) is a planet carrier, the second input member (26) of the epicyclic gear train (22) is a toothed ring and the output member (28) of the epicyclic gear train (22) is an inner planet gear, the planet carrier carrying planets (221) meshing both with the inner planet gear and with the toothed ring.

9. Drive assembly (14) according to claim 8, characterized in that: - the ratio of the number of teeth of the toothed ring to the number of teeth of the inner planetary gear is between 1.5 and 9, and / or - the first kinematic linkage (L1) and the second kinematic linkage (L2) being such that the first speed ratio and the second speed ratio have the same sign.

10. Drive assembly (14) according to claim 8 or claim 9, characterized in that the first kinematic linkage (L1) comprises at least one driving gear (21) integral with the driving shaft (20) meshing with a driven gear (23) integral with the first input member (24) of the epicyclic train (22), the second kinematic linkage (L2) comprises at least one second driving gear (25) integral with the driving shaft (20) meshing with a second driven gear (27) integral with the second input member (26) of the epicyclic train (22), and in that: - the first driven gear (23) has a pitch diameter greater than the second driven gear (27); - the second driving gear (25) has a pitch diameter greater than the first driving gear (21); - the first receiving gear (23) has a pitch diameter greater than the first driving gear (21);- the second receiving gear (27) has a pitch diameter greater than the second driving gear (25); and - the ring gear has a pitch diameter greater than the inner planetary gear.

11. A drive assembly (14) according to any one of claims 1 to 4, characterized in that the first input member (24) of the epicyclic gear train (22) is an inner planet gear, the second input member (26) of the epicyclic gear train (22) is a toothed ring and the output member (28) of the epicyclic gear train (22) is a planet carrier, the planet carrier carrying planets (221) meshing both with the inner planet gear and with the toothed ring.

12. Drive assembly (14) according to claim 11, characterized in that: - the ratio of the number of teeth of the toothed ring to the number of teeth of the inner planetary gear is between 1.5 and 4, and / or - the first kinematic linkage (L1) and the second kinematic linkage (L2) are such that the first speed ratio and the second speed ratio have opposite signs.

13. A drive assembly (14) according to claim 11 or claim 12, characterized in that the first kinematic linkage (L1) comprises at least one driving gear (21) integral with the driving shaft (20) meshing with an intermediate gear (17), meshing with a driven gear (23) integral with the first input member (24) of the epicyclic gear train (22), the second kinematic linkage (L2) comprises at least one second driving gear (25) integral with the driving shaft (20) meshing with a second driven gear (27) integral with the second input member (26) of the epicyclic gear train (22), and in that: - the second receiving gear (27) has a pitch diameter greater than the first receiving gear (23); - the first driving gear (21) has a pitch diameter greater than the second driving gear (25); - the second receiving gear (27) has a pitch diameter greater than the second driving gear (25); - the first receiving gear (23) has a pitch diameter greater than the first driving gear (21); - the crown has a pitch diameter greater than the inner planetary gear.

14. Drive assembly (14) according to any one of the preceding claims, characterized in that the rotating electric machine (16) is coaxial with the drive shaft (20) and axially positioned on the same side of the input member (24) of the epicyclic gear train (22) as the receiving member (12).