Transmission mechanism and drive unit

Abstract

A transmission mechanism and a drive unit. The transmission mechanism (18) comprises a drive shaft (20), a receiving member (12) rotating about an axis of rotation (32), and a planetary gear set (22) comprising a first input member (24), a second input member (26), and an output member (28) rigidly connected to the receiving member (12) for rotation therewith; the transmission mechanism (18) comprises: a first kinematic chain (L1) having a first speed ratio between the drive shaft (20) and a first input member (24) of the planetary gear set (22) different from 1; and a second kinematic chain (L2) having a second speed ratio between the drive shaft (20) and a second input member (26) of the planetary gear set (22) that is different from 1 and from the first speed ratio. The driving unit comprises a rotating motor (16) and the transmission mechanism (18).

Description

Technical Field

[0001] The utility model relates to a transmission mechanism, which is intended to drive a motorized machine (e.g., a motor vehicle, a motorcycle, a personal transporter (PT), a vehicle for transporting a person with limited mobility, or an autonomous vehicle), or drive equipment (e.g., a power output device of a construction vehicle or an agricultural vehicle). The utility model also relates to a drive unit comprising such a transmission mechanism. Background Art

[0002] EP 3630521 describes a transmission mechanism comprising: a drive shaft driven by an electric motor; a receiving member consisting of a differential rotating about an axis of rotation coaxial with the drive shaft; a main planetary gear set comprising a first input member, a second input member and an output member rigidly connected to the receiving member; and a chain between the drive shaft and the first input member of the main planetary gear set, wherein the speed ratio is equal to 1. The second input member of the main planetary gear set is driven by at least one secondary shaft parallel to the drive shaft, which is arranged so that the occupied space occupied in the axial direction is large and a high speed ratio cannot be generated between the drive shaft and the receiving member. In the absence of an adequate gear reduction in the transmission mechanism, the electric motor must then be dimensioned to transmit a high torque, which is undesirable. Utility Model Content

[0003] The present invention seeks to overcome the drawbacks of the prior art and proposes a compact transmission mechanism which makes it possible to obtain high torque and low drive speed at the output of the mechanism.

[0004] To this end, according to a first aspect of the utility model, a transmission mechanism is proposed, the transmission mechanism comprising: a drive shaft; a receiving member, the receiving member rotates around a rotation axis; a planetary gear set, the planetary gear set comprising a first input member, a second input member and an output member, the output member is rigidly connected to the receiving member to rotate together with the receiving member. The transmission mechanism comprises: a first kinematic chain, the first kinematic chain having a first speed ratio different from 1 between the drive shaft and the first input member of the planetary gear set; and a second kinematic chain, the second kinematic chain having a second speed ratio different from 1 and different from the first speed ratio between the drive shaft and the second input member of the planetary gear set.

[0005] The advantage of this arrangement is that, from a single input speed generated by a single drive shaft, two different output speeds of the kinematic chain are imposed, which makes it possible to save space for positioning an input member (e.g. an electric machine) rigidly connected to the drive shaft. For a similar occupied space, this arrangement also makes it possible to propose a series of transmission mechanisms whose speed ratios vary within a very wide range, depending on the size of the planetary gears of the planetary gear set and the choice of the input member of the planetary gear set.

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

[0007] According to one embodiment, the drive shaft is parallel to the rotation axis of the planetary gear set. According to one embodiment, the planetary gear set and the receiving member are coaxial. Alternatively, the rotation axis of the planetary gear set is parallel to the rotation axis of the receiving member and is separated from the rotation axis of the receiving member.

[0008] The first kinematic chain links the drive shaft to the output member. According to one embodiment, the first kinematic chain may in particular comprise:

[0009] a drive gear rigidly connected to the drive shaft that meshes with a driven gear rigidly connected to the first input member of the planetary gear set; or

[0010] a drive gear rigidly connected to the drive shaft driving a chain which drives a driven gear rigidly connected to the first input member of the planetary gear set; or

[0011] A drive gear rigidly connected to the drive shaft drives a belt that drives a driven gear rigidly connected to the first input member of the planetary gear set.

[0012] Similarly, a second kinematic chain, different from the first kinematic chain, links the drive shaft to the output member and may include:

[0013] a second drive gear rigidly connected to the drive shaft and meshing with a second driven gear rigidly connected to the second input member of the planetary gear set; or

[0014] A second drive gear rigidly connected to the drive shaft drives a belt that drives a driven gear rigidly connected to the first input member of the planetary gear set.

[0015] The proposed mechanism makes it possible to obtain high transmission ratios. According to one embodiment, the mechanism has a speed ratio between the drive shaft and the receiving member within a ratio whose absolute value is greater than 15, for example greater than 50, preferably greater than 100. Higher ratios (for example greater than 200) can be obtained without incurring specific geometrical constraints.

[0016] According to various embodiments, the planetary gear set may in particular have three configurations, each resulting in a set of conditions to be met.

[0017] According to a first embodiment, the first input member of the planetary gear set is an internal sun gear, the output member of the planetary gear set is a ring gear, and the second input member of the planetary gear set is a planet carrier, which supports planetary gears meshing with both the internal sun gear and the ring gear. By implementing, preferably cumulatively implementing, the following provisions, in particular a high speed ratio can be obtained:

[0018] The ratio of the number of teeth of the ring gear to the number of teeth of the inner sun gear is between 1.5 and 3, and / or

[0019] The first kinematic chain and the second kinematic chain are such that the first speed ratio and the second speed ratio have the same sign.

[0020] According to a particularly effective embodiment, the first kinematic chain comprises at least one drive gear rigidly connected to the drive shaft meshing with a driven gear rigidly connected to the first input member of the planetary gear set, and the second kinematic chain comprises at least one second drive gear rigidly connected to the drive shaft meshing with a second driven gear rigidly connected to the second input member of the planetary gear set. In this embodiment, the pitch circle diameter of the second driven gear is greater than the pitch circle diameter of the first driven gear, the pitch circle diameter of the first drive gear is greater than the pitch circle diameter of the second drive gear, the pitch circle diameter of the second driven gear is greater than the pitch circle diameter of the second drive gear, the pitch circle diameter of the first driven gear is greater than the pitch circle diameter of the first drive gear, and the diameter of the ring gear is greater than the diameter of the inner sun gear.

[0021] According to another embodiment, the first input member of the planetary gear set is a planet carrier, the second input member of the planetary gear set is a ring gear, and the output member of the planetary gear set is an internal sun gear, the planet carrier supporting planetary gears meshing with both the internal sun gear and the ring gear. By implementing, preferably cumulatively implementing, the following provisions, in particular a high speed ratio can be obtained:

[0022] The ratio of the number of teeth of the ring gear to the number of teeth of the inner sun gear is between 1.5 and 9, and / or

[0023] The first kinematic chain and the second kinematic chain are such that the first speed ratio and the second speed ratio have the same sign.

[0024] According to a particularly effective embodiment, the first kinematic chain comprises at least one drive gear rigidly connected to the drive shaft meshing with a driven gear rigidly connected to the first input member of the planetary gear set, and the second kinematic chain comprises at least one second drive gear rigidly connected to the drive shaft meshing with a second driven gear rigidly connected to the second input member of the planetary gear set. In this embodiment, the pitch circle diameter of the first driven gear is greater than the pitch circle diameter of the second driven gear, the pitch circle diameter of the second drive gear is greater than the pitch circle diameter of the first drive gear, the pitch circle diameter of the first driven gear is greater than the pitch circle diameter of the first drive gear, the pitch circle diameter of the second driven gear is greater than the pitch circle diameter of the second drive gear, and the pitch circle diameter of the ring gear is greater than the pitch circle diameter of the inner sun gear.

[0025] According to another embodiment, the first input member of the planetary gear set is an internal sun gear, the second input member of the planetary gear set is a ring gear, and the output member of the planetary gear set is a planet carrier, which supports planetary gears meshing with both the internal sun gear and the ring gear. By implementing, preferably cumulatively implementing, the following provisions, in particular a high speed ratio can be obtained:

[0026] The ratio of the number of teeth of the ring gear to the number of teeth of the inner sun gear is between 1.5 and 4, and / or

[0027] The first kinematic chain and the second kinematic chain are such that the first speed ratio and the second speed ratio have opposite signs.

[0028] For kinematic chains generated using gears, this difference in sign can be obtained in particular by having an even number of gears in one kinematic chain and an odd number of gears in the other kinematic chain. For kinematic chains generated using belts or chains, the reversal can be obtained by deleting one of the belts or chains. According to a particularly effective embodiment, the first kinematic chain comprises at least one drive gear rigidly connected to the drive shaft, meshing with an intermediate gear meshing with a driven gear rigidly connected to the first input member of the planetary gear set, and the second kinematic chain comprises at least one second drive gear rigidly connected to the drive shaft, meshing with a second driven gear rigidly connected to the second input member of the planetary gear set. In this embodiment, the pitch diameter of the second driven gear is greater than the pitch diameter of the first driven gear, the pitch diameter of the first drive gear is greater than the pitch diameter of the second drive gear, the pitch diameter of the second driven gear is greater than the pitch diameter of the second drive gear, the pitch diameter of the first driven gear is greater than the pitch diameter of the first drive gear, and the pitch diameter of the ring gear is greater than the pitch diameter of the inner sun gear.

[0029] According to a preferred embodiment, in order to increase the compactness of the mechanism, the receiving member is an output differential driving two output shafts coaxial with the main rotation axis of the planetary gear set, one of the two output shafts passing through the planetary gear set. Alternatively, the receiving member is an output differential driving two output shafts parallel to the main rotation axis of the planetary gear set.

[0030] According to one embodiment, the receiving member is a shaft driving the wheels. According to another embodiment, the receiving member is a power take-off.

[0031] According to one embodiment, a gear is rigidly connected to the drive shaft for rotation therewith and is axially located at a smaller distance from the motor than the second kinematic chain, said gear making it possible to link the drive shaft to the parking brake.

[0032] In addition, the utility model also relates to a drive unit, which includes a rotary motor and a transmission mechanism, wherein the rotary motor is coaxial with the drive shaft, and the rotary motor and the receiving member are axially positioned on the same side of the input member of the planetary gear set. The drive unit can be a drive unit for driving a power output device or a load, or a propulsion unit for a motor vehicle.

[0033] Preferably, the drive shaft is driven directly by the electric motor.

[0034] Advantageously, when the transmission unit is viewed in the axial direction defined by the rotation axis of the drive shaft, the outer diameter of the motor may partially cover the outer diameter of the second driven gear. Thus, the transmission unit has a radially compact structure relative to the drive shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Additional features and advantages of the present invention will become apparent from the following description read with reference to the accompanying drawings.

[0036] Figure 1 A vehicle powertrain including a propulsion unit and a transmission mechanism according to a first embodiment of the present invention is shown;

[0037] Figure 2 A vehicle powertrain including a propulsion unit and a transmission mechanism according to a second embodiment of the present invention is shown;

[0038] Figure 3 A vehicle powertrain including a propulsion unit and a transmission mechanism according to a third embodiment of the present invention is shown;

[0039] Figure 4 A vehicle powertrain including a propulsion unit and a transmission mechanism according to a fourth embodiment of the present invention is shown;

[0040] Figure 5A vehicle powertrain including a propulsion unit and a transmission mechanism according to a fifth embodiment of the present invention is shown;

[0041] Figure 6 A vehicle powertrain including a propulsion unit and a transmission mechanism according to a sixth embodiment of the present invention is shown;

[0042] For greater clarity, elements having the same or similar functions are identified with the same reference numerals in all the drawings. DETAILED DESCRIPTION

[0043] Figure 1 A vehicle drive train 10 is shown, more particularly, but not exclusively, intended for a soft mobility vehicle, comprising a receiving member 12 driven by a drive unit 14 , in this case a propulsion unit.

[0044] The propulsion unit 14 comprises a rotary electric machine 16 and a transmission 18 kinematically linking the electric machine 16 to the receiving member 12 of the vehicle. The transmission 18 comprises a drive shaft 20 driven directly by the electric machine 16 and coaxial with the electric machine 16.

[0045] The transmission mechanism 18 has a speed reducer function. To this end, the transmission mechanism 18 is composed of a planetary gear set 22, which includes a first input member 24, a second input member 26 and an output member 28. Figure 1 In the embodiment of the present invention, the first input member 24 of the planetary gear set 22 is a sun gear, the output member 28 of the planetary gear set 22 is a ring gear, and the second input member 26 of the planetary gear set 22 is a planet carrier, which is kinematically linked to a row of planetary gears 221 that mesh with the first input member 24 and the output member 28 of the planetary gear set 22.

[0046] The first kinematic chain L1 links the drive shaft 20 to the first input member 24 of the planetary gear set 22. The first kinematic chain L1 is constructed by rigidly connecting a rotation input member (here, the first drive gear 21) to the drive shaft 20 to rotate together therewith and meshing with a rotation output member (here, the first driven gear 23). The first driven gear 23 of the first kinematic chain L1 is rigidly connected to the first input member 24 of the planetary gear set 22 to rotate together therewith.

[0047] The second kinematic chain L2 links the drive shaft 20 to the second input member 26 of the planetary gear set 22. The second kinematic chain is formed by rigidly connecting the second rotational input member (here the second drive gear 25) to the drive shaft 20 to rotate together therewith and meshing with the rotational output member (here the second driven gear 27). The second driven gear 27 is rigidly connected to the second input member 26 of the planetary gear set 22 to rotate together therewith.

[0048] The axial distance between the first kinematic chain L1 and the motor 16 is preferably greater than the axial distance between the second kinematic chain L2 and the motor 16 .

[0049] The first kinematic chain L1 allows a first reduction ratio to be generated between the drive shaft 20 and the first input member 24 of the planetary gear set 22. The second kinematic chain L2 allows a second reduction ratio to be generated between the drive shaft 20 and the second input member 26 of the planetary gear set 22, which is different from the first speed ratio.

[0050] exist Figure 1 In the embodiment of the present invention, the transmission mechanism is characterized in that:

[0051] The ratio of the number of teeth of the output member 28 of the planetary gear set 22 to the number of teeth of the first input member 24 of the planetary gear set 22 is between 1.5 and 3;

[0052] The pitch circle diameter of the second driven gear 27 is greater than the pitch circle diameter of the first driven gear 23;

[0053] The pitch circle diameter of the first driving gear 21 is larger than the pitch circle diameter of the second driving gear 25;

[0054] The pitch circle diameter of the second driven gear 27 is larger than the pitch circle diameter of the second driving gear 25;

[0055] The pitch circle diameter of the first driven gear 23 is larger than the pitch circle diameter of the first driving gear 21;

[0056] The output member 28 of the planetary gear set 22 has a diameter that is greater than the diameter of the input member 24 of the planetary gear set 22 .

[0057] In practice, the speed ratio between the drive shaft 20 of the transmission 18 and the receiving member 12 is within a ratio greater than 15, preferably greater than 50, more preferably greater than 100.

[0058] According to other variations not shown, one and / or the other of the first motion chain L1 and the second motion chain L2 can be composed of a drive gear rigidly connected to the drive shaft 20 for driving a chain of a driven gear that drives the first input member 24 rigidly connected to the planetary gear set 22; or can be composed of a drive gear rigidly connected to the drive shaft 20 for driving a belt of a driven gear that drives the first input member 24 rigidly connected to the planetary gear set 22.

[0059] The output member 28 of the planetary gear set 22 is rigidly connected to the receiving member 12 of the vehicle for rotation therewith. Figure 1In the exemplary embodiment of FIG. 4 , the receiving member 12 is a wheel 11 which comprises a rotation axis 32 which is coaxial with the main rotation axis 30 of the planetary gear set 22 .

[0060] The primary axis of rotation 30 of the planetary gear set 22 and the drive shaft 20 of the transmission 18 are parallel but separated, coplanar or preferably non-coplanar.

[0061] When the transmission unit 14 is viewed along the axial direction defined by the rotation axis of the drive shaft 20 , the outer diameter of the motor 16 may partially cover the outer diameter of the second driven gear 27 .

[0062] Figure 1 A plurality of rotating guide bearings are shown to ensure satisfactory force transmission, in particular torque transmission: a first guide bearing 29 at the input of the motor 16, a guide bearing 31 at the output of the motor 16, a guide bearing 33 at the input of the first motion chain L1, a guide bearing 35 at the output of the first motion chain L1, a guide bearing 37 at the output of the output member 28 of the planetary gear set 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.

[0063] The gear 19 is rigidly connected to the drive shaft 20 for rotation therewith and, for example, axially at a smaller distance from the motor 16 than the second kinematic chain L2 , which gear may make it possible to connect the drive shaft 20 to a parking brake (not shown).

[0064] Figure 2 The illustrated embodiment differs from the previous embodiment in that the second input member 26 of the planetary gear set 22 is a ring gear, the output member 28 of the planetary gear set 22 is a sun gear, and the first input member 24 of the planetary gear set 22 is a planet carrier kinematically linked to a row of planet gears 221 meshing with the second input member 26 and the output member 28 of the planetary gear set 22. The ring gear rotates about the main rotation axis 30 of the planetary gear set 22. A rotary guide bearing 43 guides the ring gear.

[0065] exist Figure 2 In the embodiment of the present invention, the transmission mechanism is characterized in that:

[0066] The ratio of the number of teeth of the output member 28 of the planetary gear set 22 to the number of teeth of the first input member 24 of the planetary gear set 22 is between 1.5 and 9;

[0067] The pitch circle diameter of the first driven gear 23 is greater than the pitch circle diameter of the second driven gear 27;

[0068] The pitch circle diameter of the second driving gear 25 is larger than the pitch circle diameter of the first driving gear 21;

[0069] The pitch circle diameter of the first driven gear 23 is larger than the pitch circle diameter of the first driving gear 21;

[0070] The pitch circle diameter of the second driven gear 27 is larger than the pitch circle diameter of the second driving gear 25;

[0071] The output member 28 of the planetary gear set 22 has a diameter that is greater than the diameter of the input member 24 of the planetary gear set 22 .

[0072] Figure 3 The illustrated embodiment differs from the previous embodiment in that the first input member 24 of the planetary gear set 22 is a sun gear, the second input member 26 is a ring gear, and the rotating output member 28 is a planet carrier, which is kinematically linked to a row of planetary gears 221 that mesh with the first input member 24 and the second input member 26 of the planetary gear set 22.

[0073] In this embodiment, the first kinematic chain L1 is formed by meshing the first drive gear 21 with the intermediate gear 17 meshing with the first driven gear 23 .

[0074] exist Figure 3 In the embodiment of the present invention, the transmission mechanism is characterized in that:

[0075] The ratio of the number of teeth of the output member 28 of the planetary gear set 22 to the number of teeth of the first input member 24 of the planetary gear set 22 is between 1.5 and 4;

[0076] The pitch circle diameter of the second driven gear 27 is greater than the pitch circle diameter of the first driven gear 23;

[0077] The pitch circle diameter of the first driving gear 21 is larger than the pitch circle diameter of the second driving gear 25;

[0078] The pitch circle diameter of the second driven gear 27 is larger than the pitch circle diameter of the second driving gear 25;

[0079] The pitch circle diameter of the first driven gear 23 is larger than the pitch circle diameter of the first driving gear 21;

[0080] The output member 28 of the planetary gear set 22 has a diameter that is greater than the diameter of the input member 24 of the planetary gear set 22 .

[0081] Figure 4 The embodiment shown is Figure 1The embodiment shown differs in that the receiving member 12 of the transmission 18 is an output differential 34 which drives two output half shafts 36 and 38 coaxial with the main axis of rotation 30 of the planetary gear set, one half shaft 36 passing through the planetary gear set 22. In this configuration, the main axis of rotation 30 of the planetary gear set 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.

[0082] A similar construction of the output differential 34 as a receiving member 12 of the transmission mechanism 18 can be obtained from Figure 2 or Figure 3 It is modified from the organization in .

[0083] Figure 5 The embodiment shown is Figure 2 The embodiment shown differs in that the axis of rotation 32 of the output wheel 11 is parallel to but not coincident with the main axis of rotation 30 of the planetary gear set 22, and a drive gear 40 is rigidly connected to the output member 24 of the planetary gear set 22 for rotation therewith, which meshes with a driven gear 42 which is rigidly connected to rotate therewith with the axis of rotation of the wheel 11. In this embodiment, the transmission 18 includes a guide bearing 49 at the output of the main axis of rotation 30 of the planetary gear set 22.

[0084] A similar configuration may be employed where the output member's axis of rotation 32 is parallel to, but not coincident with, the primary axis of rotation 30 of the planetary gear set. Figure 1 or Figure 3 The embodiments in .

[0085] Figure 6 The embodiment shown is Figure 4 The embodiment shown differs in that the two output half shafts 36 and 38 of the output differential 34 are parallel to and equidistant from the main axis of rotation 30 of the planetary gear set 22. A drive gear 48 is rigidly connected to the main axis 30 of the planetary gear set 22 for rotation therewith and meshes with an input member 50 of the output differential 34. In this embodiment, the transmission 18 comprises a pilot bearing 49 at the output of the main axis of rotation 30 of the planetary gear set 22, a pilot bearing 51 at the end of the differential around the output half shaft 36, and a pilot bearing 53 at the end of the differential around the output half shaft 38.

[0086] from Figure 2 or Figure 3 A similar structure can be derived from the mechanism in .

[0087] Of course, the examples shown in the figures and described above are given only by way of non-limiting illustration. In order to propose further embodiments, it is expressly proposed to combine the various embodiments shown.

Claims

1. A transmission mechanism (18), comprising: A drive shaft (20), a receiving member (12) which rotates about an axis of rotation (32), a planetary gear set (22) comprising a first input member (24), a second input member (26), and an output member (28) rigidly connected to the receiving member (12) for rotation therewith; The transmission mechanism (18) is characterized in that the transmission mechanism (18) includes: a first kinematic chain (L1), the first kinematic chain having a first speed ratio different from 1 between the drive shaft (20) and the first input member (24) of the planetary gear set (22); and a second kinematic chain (L2), the second kinematic chain having a second speed ratio different from 1 and different from the first speed ratio between the drive shaft (20) and the second input member (26) of the planetary gear set (22).

2. The transmission mechanism (18) according to claim 1, characterized in that: The first kinematic chain (L1) comprises at least: a drive gear (21) rigidly connected to the drive shaft (20) meshing with a driven gear (23), the driven gear (23) rigidly connected to the first input member (24) of the planetary gear set (22); or a drive gear rigidly connected to the drive shaft (20) driving a chain, the chain driving a driven gear rigidly connected to the first input member of the planetary gear set; or A drive gear rigidly connected to the drive shaft (20) drives a belt that drives a driven gear rigidly connected to the first input member of the planetary gear set.

3. The transmission mechanism (18) according to claim 1 or 2, characterized in that: The second kinematic chain (L2) comprises at least: a second drive gear (25) rigidly connected to the drive shaft (20) and meshing with a second driven gear (27), the second driven gear (27) being rigidly connected to the second input member (26) of the planetary gear set (22); or A second drive gear rigidly connected to the drive shaft (20) drives a belt that drives a driven gear rigidly connected to the first input member of the planetary gear set.

4. The transmission mechanism (18) according to claim 1 or 2, characterized in that: The transmission mechanism (18) has a speed ratio between the drive shaft (20) and the receiving member (12) with an absolute value greater than 15.

5. The transmission mechanism (18) according to claim 1 or 2, characterized in that: The transmission mechanism (18) has a speed ratio between the drive shaft (20) and the receiving member (12) whose absolute value is greater than 50.

6. The transmission mechanism (18) according to claim 1 or 2, characterized in that: The transmission mechanism (18) has a speed ratio between the drive shaft (20) and the receiving member (12) whose absolute value is greater than 100.

7. The transmission mechanism (18) according to claim 1, characterized in that: The first input member (24) of the planetary gear set (22) is an internal sun gear, the output member (28) of the planetary gear set (22) is a ring gear, and the second input member (26) of the planetary gear set (22) is a planet carrier, which supports planetary gears (221) that mesh with both the internal sun gear and the ring gear.

8. The transmission mechanism (18) according to claim 7, characterized in that: The ratio of the number of teeth of the ring gear to the number of teeth of the inner sun gear is between 1.5 and 3, and / or The first kinematic chain (L1) and the second kinematic chain (L2) are such that the first speed ratio and the second speed ratio have the same sign.

9. The transmission mechanism (18) according to claim 7 or claim 8, characterized in that: The first kinematic chain (L1) comprises at least one first drive gear (21) rigidly connected to the drive shaft (20) meshing with a first driven gear (23) rigidly connected to the first input member of the planetary gear set (22), and the second kinematic chain (L2) comprises at least one second drive gear (25) rigidly connected to the drive shaft (20) meshing with a second driven gear (27) rigidly connected to the second input member (26) of the planetary gear set (22), and: The pitch circle diameter of the second driven gear (27) is greater than the pitch circle diameter of the first driven gear (23); The pitch circle diameter of the first driving gear (21) is greater than the pitch circle diameter of the second driving gear (25); The pitch circle diameter of the second driven gear (27) is greater than the pitch circle diameter of the second driving gear (25); The pitch circle diameter of the first driven gear (23) is greater than the pitch circle diameter of the first driving gear (21); and The diameter of the ring gear is greater than the diameter of the inner sun gear.

10. The transmission mechanism (18) according to claim 1, characterized in that: The first input member (24) of the planetary gear set (22) is a planet carrier, the second input member (26) of the planetary gear set (22) is a ring gear, and the output member (28) of the planetary gear set (22) is an internal sun gear, and the planet carrier supports planetary gears (221) that mesh with both the internal sun gear and the ring gear.

11. The transmission mechanism (18) according to claim 10, characterized in that: The ratio of the number of teeth of the ring gear to the number of teeth of the inner sun gear is between 1.5 and 9, and / or The first kinematic chain (L1) and the second kinematic chain (L2) are such that the first speed ratio and the second speed ratio have the same sign.

12. The transmission mechanism (18) according to claim 10 or claim 11, characterized in that: The first kinematic chain (L1) comprises at least one first drive gear (21) rigidly connected to the drive shaft (20) meshing with a first driven gear (23) rigidly connected to the first input member (24) of the planetary gear set (22), and the second kinematic chain (L2) comprises at least one second drive gear (25) rigidly connected to the drive shaft (20) meshing with a second driven gear (27) rigidly connected to the second input member (26) of the planetary gear set (22), and: The pitch circle diameter of the first driven gear (23) is greater than the pitch circle diameter of the second driven gear (27); The pitch circle diameter of the second driving gear (25) is greater than the pitch circle diameter of the first driving gear (21); The pitch circle diameter of the first driven gear (23) is greater than the pitch circle diameter of the first driving gear (21); The pitch circle diameter of the second driven gear (27) is greater than the pitch circle diameter of the second driving gear (25); and The pitch circle diameter of the ring gear is greater than the pitch circle diameter of the inner sun gear.

13. The transmission mechanism (18) according to claim 1, characterized in that: The first input member (24) of the planetary gear set (22) is an inner sun gear, the second input member (26) of the planetary gear set (22) is a ring gear, and the output member (28) of the planetary gear set (22) is a planet carrier, which supports planetary gears (221) that mesh with both the inner sun gear and the ring gear.

14. The transmission mechanism (18) according to claim 13, characterized in that: The ratio of the number of teeth of the ring gear to the number of teeth of the inner sun gear is between 1.5 and 4, and / or The first kinematic chain (L1) and the second kinematic chain (L2) are such that the first speed ratio and the second speed ratio have opposite signs.

15. The transmission mechanism (18) according to claim 13 or claim 14, characterized in that: The first kinematic chain (L1) comprises at least one first drive gear (21) rigidly connected to the drive shaft (20) meshing with an intermediate gear (17), the intermediate gear (17) meshing with a first driven gear (23) rigidly connected to the first input member (24) of the planetary gear set (22), and the second kinematic chain (L2) comprises at least one second drive gear (25) rigidly connected to the drive shaft (20) meshing with a second driven gear (27) rigidly connected to the second input member (26) of the planetary gear set (22), and: The pitch circle diameter of the second driven gear (27) is greater than the pitch circle diameter of the first driven gear (23); The pitch circle diameter of the first driving gear (21) is greater than the pitch circle diameter of the second driving gear (25); The pitch circle diameter of the second driven gear (27) is greater than the pitch circle diameter of the second driving gear (25); The pitch circle diameter of the first driven gear (23) is greater than the pitch circle diameter of the first driving gear (21); The pitch circle diameter of the ring gear is greater than the pitch circle diameter of the inner sun gear.

16. The transmission mechanism (18) according to claim 1, characterized in that: The receiving member (12) is: an output differential driving two output shafts coaxial with the main axis of rotation (30) of the planetary gear set (22), one of the two output shafts passing through the planetary gear set (22); or an output differential driving two output shafts parallel to the main axis of rotation (30) of the planetary gear set (22); or the axle driving the wheels; or Power take-off device.

17. A drive unit (14), comprising: A rotary electric machine (16) and a transmission mechanism (18) according to any one of the preceding claims, the rotary electric machine (16) being coaxial with the drive shaft (20) and being axially positioned on the same side of the first input member (24) of the planetary gear set (22) as the receiving member (12).

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