Single-motor coaxial speed reducer assembly

Abstract

The invention relates to the field of new energy automobile transmission, in particular to a single-motor coaxial speed reducer assembly which comprises a motor and further comprises a speed reducing mechanism, the speed reducing mechanism comprises a first gear train and a second gear train which are coaxially arranged, the input end of the first gear train is connected with the motor through a motor shaft, and the output end of the second gear train is connected with the motor through a motor shaft. The output end of the first gear train is fixedly connected with the input end of the second gear train, and the first gear train and the second gear train are both connected with a first inner gear ring; the output end of the second gear train is fixedly connected with the input end of the differential mechanism, and the differential mechanism is connected with the second inner gear ring. Compared with a speed reducer assembly in the prior art, the single-motor coaxial type speed reducer assembly is simpler in structure, smaller in size, lower in cost and larger in transmission ratio range.

Description

Technical Field

[0001] The present application relates to the field of new energy vehicle transmission, and specifically to a single-motor coaxial reducer assembly. Background Art

[0002] With the continuous development of pure electric vehicles, users have further requirements for reducer transmission assemblies: high input speed and low torque, low output speed and high torque; small size, light weight; low noise; low cost, etc. In the prior art, coaxial reducer transmission assemblies have problems such as large size and mass, small transmission ratio range, poor running stability, high noise, many types of parts and high cost. Single-motor coaxial reducer assemblies need to be relatively small and light, with a large transmission ratio range, good running stability, low noise, few types of parts and low cost.

[0003] For example, the Chinese patent, the invention application with the publication number CN 115675039 A, discloses a single-motor coaxial two-speed electric drive axle structure, including: a drive motor; a reduction planetary gear; a second hollow shaft; a clutch; a brake; a double-star planetary gear; and a compound planetary gear differential. After the reduction planetary gear is reduced in the above invention application, a high-low speed switching clutch is arranged in the double-star planetary gear, which reduces the speed difference of the planetary gear components during gear shifting, but the transmission ratio range of the reducer is small, and the reducer occupies a large space in the drive axle. Summary of the invention

[0004] In response to the problems in the prior art, the present application proposes a single-motor coaxial reducer assembly with a simpler structure, smaller size and a wider transmission ratio range.

[0005] A single-motor coaxial reducer assembly includes a motor and a reduction mechanism, wherein the reduction mechanism includes a first gear train and a second gear train that are coaxially arranged, wherein the input end of the first gear train is connected to the motor through a motor shaft, the output end of the first gear train is fixedly connected to the input end of the second gear train, and the first gear train and the second gear train are both connected to a first inner gear ring; and a differential mechanism, wherein the output end of the second gear train is fixedly connected to the input end of the differential mechanism, and the differential mechanism is connected to the second inner gear ring.

[0006] The first gear train and the second gear train of the reduction mechanism are two fixed-axis gear trains, which reduce the high speed output by the motor twice to a low speed and increase the torque; the differential mechanism is a revolving gear train, which converts the low speed and high torque output by the reduction mechanism into different speeds and outputs them; the reduction mechanism and the differential mechanism are coaxially arranged, which further reduces the size of the single-motor coaxial reducer.

[0007] The first gear train includes a first sun gear and a first planet carrier which are coaxially arranged. The first gear train includes a first sun gear and a first planet carrier which are coaxially arranged. At least two first planet gears are arranged on the first planet carrier. The circumferential side of the first planet gear is connected to the first inner gear ring.

[0008] The second gear train includes a coaxially arranged second sun gear and a second planet carrier, the second planet carrier is provided with at least two second planet gears, the circumference of the second planet gear is connected to the first inner ring gear, and the second sun gear is fixedly connected to the first planet carrier.

[0009] The differential mechanism includes a coaxially arranged third sun gear and a third planet carrier, the third planet carrier is provided with at least two third planet gears, the circumferential side of the third planet gear is connected to the second inner ring gear, and the third sun gear is fixedly connected to the second planet carrier.

[0010] The first planetary gear is constantly meshed with the first sun gear, the first planetary gear is constantly meshed with the first inner ring gear, the second planetary gear is constantly meshed with the second sun gear, the second planetary gear is constantly meshed with the second inner ring gear, the third planetary gear is constantly meshed with the third sun gear, and the third planetary gear is constantly meshed with the second inner ring gear.

[0011] The third planet carrier is connected to the left tire via the left wheel transmission shaft, and the second inner gear ring is connected to the right tire via the right wheel transmission shaft.

[0012] The first inner gear ring is fixedly arranged, and the second inner gear ring is movably arranged.

[0013] The first internal gear ring has only one number of teeth.

[0014] Optionally, the first inner gear ring is a duplex gear ring.

[0015] Optionally, the number of teeth in the rear half of the first inner gear ring is greater than the number of teeth in the front half.

[0016] Beneficial effects of this application: 1. The speed reduction mechanism and differential mechanism are simpler, smaller and lighter than the existing technology; 2. The first internal gear ring can be directly installed inside the single-motor coaxial reducer assembly, reducing the assembly steps; 3. Regarding the arrangement of the first gear train and the second gear train in the reduction mechanism, the first inner gear ring can use a double gear ring to increase the adjustable range of the transmission ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a single-motor coaxial reducer assembly.

[0018] Figure 2 This is a schematic diagram of the structure of a single-motor coaxial reducer assembly connected to the left and right tires.

[0019] Figure Number: 1. Motor; 2. Speed ​​reduction mechanism; 3. Differential mechanism; 4. Left tire; 5. Right tire; 11. Motor shaft; 21. First gear train; 22. Second gear train; 23. First inner ring gear; 31. Third sun gear; 32. Third planetary gear; 33. Third planet carrier; 34. Second inner ring gear; 41. Left wheel transmission shaft; 42. Right wheel transmission shaft; 211, first sun gear; 212, first planetary gear; 213, first planet carrier; 221, second sun gear; 222, second planetary gear; 223, second planet carrier; DETAILED DESCRIPTION

[0020] The motor reducer is an important device in new energy vehicles. It can take the high speed and low torque output by the motor as input, and output low speed and high torque, thereby improving the driving stability of the vehicle and better coping with working conditions such as uphill and acceleration. The development of pure electric vehicles requires the motor reducer assembly to have a smaller size, lighter weight, lower noise, and reduced manufacturing costs. However, the single motor coaxial reducer in the prior art is relatively large in size, and the multi-stage reduction structure is difficult to assemble. In the planetary gear reducer, the assembly steps of the inner ring are cumbersome. In view of the problems of the prior art, the present application proposes a single motor coaxial reducer assembly, which has a simpler structure than the structure in the prior art, is less difficult to assemble, and has a lower manufacturing cost. The technical effects of the present application are further explained in conjunction with specific implementation methods below.

[0021] Embodiment 1, refer to the attached Figure 1 A single-motor coaxial reducer assembly includes a motor 1 and a reduction mechanism 2, wherein the reduction mechanism 2 includes a first gear train 21 and a second gear train 22 which are coaxially arranged, wherein the input end of the first gear train 21 is connected to the motor 1 through a motor shaft 11, and the output end of the first gear train 21 is fixedly connected to the input end of the second gear train 22, and both the first gear train 21 and the second gear train 22 are connected to a first inner gear ring 23; a differential mechanism 3, wherein the output end of the second gear train 22 is fixedly connected to the input end of the differential mechanism 3, and the differential mechanism 3 is connected to a second inner gear ring 34.

[0022] In the single-motor coaxial reducer assembly in this embodiment, the first gear train 21 and the second gear train 22 are two fixed-axis gear trains. The first gear train 21 is closer to the motor 1 than the second gear train 22. The motor shaft 11 of the motor 1 is connected to the first gear train 21. The motor shaft 11 inputs power into the first gear train 21. The first gear train 21 and the second gear train 22 convert high-speed and low-torque into low-speed and high-torque.

[0023] Reference Figure 1 The first gear train 21 includes a coaxially arranged first sun gear 211 and a first planetary carrier 213, at least two first planetary gears 212 are provided on the first planetary carrier 213, and the circumferential side of the first planetary gear 212 is connected to the first inner ring gear 23, the second gear train 22 includes a coaxially arranged second sun gear 221 and a second planetary carrier 223, at least two second planetary gears 222 are provided on the second planetary gear 222, the circumferential side of the second planetary gear 222 is connected to the first inner ring gear 23, and the second sun gear 221 is fixedly connected to the first planetary carrier 213. The first sun gear 211 is coaxially arranged with the first planet carrier 213, and two first planetary gears 212 are arranged on the first planet carrier 213. The first planetary gears 212 are constantly meshed with the first sun gear 211, and the two first planetary gears 212 are evenly distributed on the end surface of the first planet carrier 213 close to the first sun gear 211; the first inner gear ring 23 is fixedly arranged inside the housing of the single-motor coaxial reducer assembly, and the first planetary gears 212 are constantly meshed with the first inner gear ring 23; the second sun gear 221 is coaxially arranged with the second planet carrier 223, and the first sun gear 2 11. The first planet carrier 213, the second sun gear 221 and the second planet carrier 223 are all coaxially arranged; the second planet carrier 223 is provided with two second planet gears 222, and the two second planet gears 222 are evenly distributed on the end surface of the second planet carrier 223, the second planet gears 222 are constantly meshed with the second sun gear, and the second planet gears 222 are constantly meshed with the first inner gear ring 23; the extended portion of the center hole portion of the end surface of the first planet carrier 213 away from the first sun gear is fixedly connected to the second sun gear, that is, the first planet carrier 213 inputs the rotational power to the second sun gear.

[0024] The differential mechanism 3 includes a coaxially arranged third sun gear 31 and a third planet carrier 33, at least two third planet gears 32 are arranged on the third planet carrier 33, and the circumferential side of the third planet gear 32 is connected to the second inner ring gear 34. The first planet gear 212 is constantly meshed with the first sun gear 211, the first planet gear 212 is constantly meshed with the first inner ring gear 23, the second planet gear 222 is constantly meshed with the second sun gear 221, the second planet gear 222 is constantly meshed with the second inner ring gear 34, the third planet gear 32 is constantly meshed with the third sun gear 31, and the third planet gear 32 is constantly meshed with the second inner ring gear 34. The differential mechanism 3 is used to input the low-speed and high-torque power output by the reduction mechanism 2 to the two driving wheels of the vehicle respectively; the third sun gear 31 is fixedly connected to the second planetary carrier 223, and the connection method between the first planetary carrier 213 and the second sun gear 221 is the same; the third sun gear 31 and the third planetary carrier 33 are coaxially arranged, and two third planetary gears 32 are arranged on the end face of the third planetary carrier 33, and the third planetary gears 32 are evenly distributed on the end face of the third planetary carrier 33, and the third planetary gears 32 are constantly meshed with the third sun gear, and the third planetary gears 32 are constantly meshed with the second inner ring gear 34; the second inner ring gear 34 is coaxially arranged with the third planetary carrier 33, and the second inner ring gear 34 is rotatably connected in the outer shell of the single-motor coaxial reducer assembly; the reduction mechanism 2 transmits power to the differential mechanism 3, and according to the transmission ratio between the third sun gear and the second inner ring gear 34 in the differential mechanism 3, the third sun gear 31 and the second inner ring gear 34 produce different rotation speeds.

[0025] Reference Figure 1 and Figure 2 , the third planet carrier 33 is connected to the left tire 4 through the left wheel transmission shaft 41, and the second inner gear ring 34 is connected to the right tire 5 through the right wheel transmission shaft 42. The differential mechanism 3 transmits power to the vehicle driving wheel by connecting two vehicle transmission shafts, and at the same time makes the left and right tires 5 produce different rotation speeds; the left wheel transmission shaft 41 is sequentially arranged in the motor 1, the reduction mechanism 2 and the differential mechanism 3, one end of the left wheel transmission shaft 41 is connected to the left tire 4, and the other end is connected to the third sun gear of the differential mechanism 3; the right wheel transmission shaft 42 is arranged in the differential mechanism 3, one end of the right wheel transmission shaft 42 is connected to the second inner gear ring 34, and the other end is connected to the right tire 5. Since the differential mechanism 3 is an epicyclic gear train, the second inner gear ring 34 is rotatably connected to the inner shell of the single motor coaxial reducer assembly, and the differential rotation of the left and right wheels can be realized.

[0026] The motion process of the single motor coaxial reducer assembly in this embodiment is as follows: The motor 1 outputs high speed and low torque through the motor shaft 11. The first sun gear 211 is fixedly connected to the motor shaft 11. Since the first inner gear ring 23 is fixedly set, the first sun gear 211 transmits power to the first planetary carrier 213; according to the transmission ratio between the first sun gear 211 and the first inner gear ring 23, the high speed output by the motor shaft 11 is reduced, and the first planetary carrier 213 is fixedly connected to the second sun gear 221, that is, the second sun gear 221 has the same speed as the first planetary carrier 213; the number of front and rear teeth of the first inner gear ring 23 is Similarly, the second gear train 22 further decelerates the rotation speed output by the first gear train 21, and the torque is increased; the second sun gear 221 is fixedly connected to the third sun gear 31 of the differential mechanism 3, that is, the rotation speed of the third sun gear 31 is the same as that of the second planetary carrier 223, the third sun gear 31 is connected to the left tire 4 through the left wheel drive shaft 41, and the second inner ring gear 34 is connected to the right tire 5 through the right wheel drive shaft 42. Due to the movable setting of the second inner ring gear 34, the left and right wheels realize differential rotation, and the left tire 4 outputs low-speed and high-torque after deceleration.

[0027] The single-motor coaxial reducer assembly in this embodiment converts the high-speed and low-torque output of the motor 1 into a low-speed and high-torque output through two fixed-axis gear trains, the first gear train 21 and the second gear train 22. The first gear train 21 and the second gear train 22 are coaxially arranged and transmit power through a first inner gear ring 23 fixedly arranged inside the shell of the single-motor coaxial reducer assembly. The first inner gear ring 23 has a uniform number of teeth at the front and rear, and can be formed and installed into the shell of the single-motor coaxial reducer assembly at one time during the assembly process, thereby simplifying the assembly process and reducing the overall volume of the single-motor coaxial reducer assembly. The speed mechanism 3 is coaxially arranged with the reduction mechanism 2, which further reduces the overall volume of the single-motor coaxial reducer assembly; the single-motor coaxial reducer assembly in this embodiment has a smaller volume than the single-motor reducer assembly in the prior art, thereby reducing the overall weight; its simple structure can reduce the manufacturing cost of the single-motor coaxial reducer assembly housing and the difficulty of assembly, and the overall cost is lower; since there is less large-area contact between the first gear train 21, the second gear train 22 and the differential mechanism 3 and the housing of the single-motor coaxial reducer assembly, the operating noise is smaller.

[0028] Embodiment 2 In this embodiment, the first internal gear ring 23 is a duplex gear ring.

[0029] The development of pure electric vehicles requires that the motor reducer assembly has a smaller size, lighter weight, lower noise, and lower manufacturing costs. However, the single motor coaxial reducer in the prior art is large in size, and the multi-stage reduction structure is difficult to assemble. In the planetary gear reducer, the assembly steps of the inner ring are cumbersome. In view of the problems of the prior art, this application proposes a single motor coaxial reducer assembly, which has a simpler structure than the structure in the prior art, is less difficult to assemble, and has a lower manufacturing cost. The technical effects of this application are further explained in combination with specific implementation methods.

[0030] Reference Figure 1 The single-motor coaxial reducer assembly in this embodiment includes a motor 1 and a reduction mechanism 2. The reduction mechanism 2 includes a first gear train 21 and a second gear train 22 that are coaxially arranged. The input end of the first gear train 21 is connected to the motor 1 through the motor shaft 11, and the output end of the first gear train 21 is fixedly connected to the input end of the second gear train 22. The first gear train 21 and the second gear train 22 are both connected to the first inner gear ring 23; a differential mechanism 3, and the output end of the second gear train 22 is fixedly connected to the input end of the differential mechanism 3, and the differential mechanism 3 is connected to the second inner gear ring 34.

[0031] In the single-motor coaxial reducer assembly in this embodiment, the first gear train 21 and the second gear train 22 are two fixed-axis gear trains. The first gear train 21 is closer to the motor 1 than the second gear train 22. The motor shaft 11 of the motor 1 is connected to the first gear train 21. The motor shaft 11 inputs power into the first gear train 21. The first gear train 21 and the second gear train 22 convert high-speed and low-torque into low-speed and high-torque.

[0032] Reference Figure 1The first gear train 21 includes a coaxially arranged first sun gear 211 and a first planetary carrier 213, at least two first planetary gears 212 are provided on the first planetary carrier 213, and the circumferential side of the first planetary gear 212 is connected to the first inner ring gear 23, the second gear train 22 includes a coaxially arranged second sun gear 221 and a second planetary carrier 223, at least two second planetary gears 222 are provided on the second planetary gear 222, the circumferential side of the second planetary gear 222 is connected to the first inner ring gear 23, and the second sun gear 221 is fixedly connected to the first planetary carrier 213. The first sun gear 211 is coaxially arranged with the first planet carrier 213, and three first planetary gears 212 are arranged on the first planet carrier 213. The first planetary gear 212 is constantly meshed with the first sun gear 211, and the three first planetary gears 212 are evenly distributed on the end face of the first planet carrier 213 close to the first sun gear 211; the first inner ring gear 23 is fixedly arranged inside the outer shell of the single-motor coaxial reducer assembly, and the first planetary gear 212 is constantly meshed with the first inner ring gear 23; the second sun gear 221 is coaxially arranged with the second planet carrier 223, and the first sun gear 211, the first planet carrier 213, the second sun gear 221 and the second planet carrier 223 are all coaxially arranged; the second planetary gears 222 are arranged on the second planet carrier 223, and the three second planetary gears 222 are evenly distributed on the end face of the second planet carrier 223, and the second planetary gears 222 are constantly meshed with the second sun gear, and the second The planetary gears 222 are constantly meshed with the first inner gear ring 23; the extended portion of the center hole portion of the end face of the first planet carrier 213 away from the first sun gear is fixedly connected to the second sun gear, that is, the first planet carrier 213 inputs the rotational power to the second sun gear; since the first inner gear ring 23 is a double gear ring, that is, the number of teeth at the front and rear ends is different, the number of teeth of the portion of the first inner gear ring 23 connected with the first planetary gear 212 is smaller than the number of teeth of the portion of the first inner gear ring 23 connected with the second planetary gear 222; the rear half of the first inner gear ring 23, that is, the portion of the gear ring meshing with the second planetary gear 222, has a pitch circle radius greater than the pitch circle radius of the front half, which results in the different number of teeth of the first sun gear and the second sun gear in this embodiment, and the different number of teeth of the first planetary gear 212 and the second planetary gear 222; the transmission ratio of the first sun gear to the front half of the first inner gear ring 23 is greater than that of the second sun gear to the rear half of the first inner gear ring 23.

[0033] The differential mechanism 3 includes a coaxially arranged third sun gear 31 and a third planet carrier 33, at least two third planet gears 32 are arranged on the third planet carrier 33, and the circumferential side of the third planet gear 32 is connected to the second inner ring gear 34. The first planet gear 212 is constantly meshed with the first sun gear 211, the first planet gear 212 is constantly meshed with the first inner ring gear 23, the second planet gear 222 is constantly meshed with the second sun gear 221, the second planet gear 222 is constantly meshed with the second inner ring gear 34, the third planet gear 32 is constantly meshed with the third sun gear 31, and the third planet gear 32 is constantly meshed with the second inner ring gear 34. The differential mechanism 3 is used to input the low-speed and high-torque power output by the reduction mechanism 2 to the two driving wheels of the vehicle respectively; the third sun gear 31 is fixedly connected to the second planetary carrier 223, and the connection method between the first planetary carrier 213 and the second sun gear 221 is the same; the third sun gear 31 is coaxially arranged with the third planetary carrier 33, and three third planetary gears 32 are arranged on the end face of the third planetary carrier 33, and the third planetary gears 32 are evenly distributed on the end face of the third planetary carrier 33, and the third planetary gears 32 are constantly meshed with the third sun gear, and the third planetary gears 32 are constantly meshed with the second inner ring gear 34; the second inner ring gear 34 is coaxially arranged with the third planetary carrier 33, and the second inner ring gear 34 is rotatably connected in the outer shell of the single-motor coaxial reducer assembly; the reduction mechanism 2 transmits power to the differential mechanism 3, and according to the transmission ratio between the third sun gear and the second inner ring gear 34 in the differential mechanism 3, the third sun gear 31 and the second inner ring gear 34 produce different rotation speeds.

[0034] Reference Figure 1 and Figure 2 , the third planet carrier 33 is connected to the left tire 4 through the left wheel transmission shaft 41, and the second inner gear ring 34 is connected to the right tire 5 through the right wheel transmission shaft 42. The differential mechanism 3 transmits power to the vehicle driving wheel by connecting two vehicle transmission shafts, and at the same time makes the left and right tires 5 produce different rotation speeds; the left wheel transmission shaft 41 is sequentially arranged in the motor 1, the reduction mechanism 2 and the differential mechanism 3, one end of the left wheel transmission shaft 41 is connected to the left tire 4, and the other end is connected to the third sun gear of the differential mechanism 3; the right wheel transmission shaft 42 is arranged in the differential mechanism 3, one end of the right wheel transmission shaft 42 is connected to the second inner gear ring 34, and the other end is connected to the right tire 5. Since the differential mechanism 3 is an epicyclic gear train, the second inner gear ring 34 is rotatably connected to the inner shell of the single motor coaxial reducer assembly, and the differential rotation of the left and right wheels can be realized.

[0035] The motion process of the single motor coaxial reducer assembly in this embodiment is as follows: The motor 1 outputs high speed and low torque through the motor shaft 11. The first sun gear 211 is fixedly connected to the motor shaft 11. Since the first inner gear ring 23 is fixedly set, the first sun gear 211 transmits power to the first planetary carrier 213; according to the transmission ratio between the first sun gear 211 and the first inner gear ring 23, the high speed output by the motor shaft 11 is reduced, and the first planetary carrier 213 is fixedly connected to the second sun gear 221, that is, the second sun gear 221 has the same speed as the first planetary carrier 213; the number of front and rear teeth of the first inner gear ring 23 is Similarly, the second gear train 22 further decelerates the rotation speed output by the first gear train 21, and the torque is increased; the second sun gear 221 is fixedly connected to the third sun gear 31 of the differential mechanism 3, that is, the rotation speed of the third sun gear 31 is the same as that of the second planetary carrier 223, the third sun gear 31 is connected to the left tire 4 through the left wheel drive shaft 41, and the second inner ring gear 34 is connected to the right tire 5 through the right wheel drive shaft 42. Due to the movable setting of the second inner ring gear 34, the left and right wheels realize differential rotation, and the left tire 4 outputs low-speed and high-torque after deceleration.

[0036] The single-motor coaxial reducer assembly in this embodiment adopts a first inner gear ring 23 with a double gear ring. The transmission ratio of the second sun gear to the rear half of the first inner gear ring 23 is smaller than the transmission ratio of the first sun gear to the front half of the first inner gear ring 23, that is, a more efficient deceleration effect is achieved and a higher torque is output. To ensure stability, the number of first planetary gears 212 and second planetary gears 222 needs to be increased; the first inner gear ring 23 is a double gear ring, which is completed at one time during the assembly process of the single-motor coaxial reducer assembly, reducing the assembly steps and also improving the stability of the single-motor coaxial reducer assembly to a certain extent.

[0037] The above contents are preferred embodiments of the present application, which are used to illustrate the specific structure and functions of the present application. It should be pointed out that, without departing from the principles of the present application, ordinary technicians in this technical field can make anticipated improvements and modifications to the present application, and these improvements and modifications are also within the scope of protection of the present application.

Claims

1. A single-motor coaxial reducer assembly, comprising a motor, characterized in that: Also includes: A reduction mechanism, the reduction mechanism comprising a first gear train and a second gear train which are coaxially arranged, wherein an input end of the first gear train is connected to the motor via a motor shaft, an output end of the first gear train is fixedly connected to an input end of the second gear train, and both the first gear train and the second gear train are connected to a first inner gear ring; A differential mechanism, wherein the output end of the second gear train is fixedly connected to the input end of the differential mechanism, and the differential mechanism is connected to the second inner gear ring.

2. The single-motor coaxial reducer assembly according to claim 1, characterized in that: The first gear train includes a first sun gear and a first planet carrier which are coaxially arranged. The first planet carrier is provided with at least two first planet gears, and the circumferential sides of the first planet gears are connected to the first inner gear ring.

3. A single motor coaxial reducer assembly according to claim 2, characterized in that: The second gear train includes a coaxially arranged second sun gear and a second planet carrier, the second planet carrier is provided with at least two second planet gears, the circumference of the second planet gear is connected to the first inner ring gear, and the second sun gear is fixedly connected to the first planet carrier.

4. The single-motor coaxial reducer assembly according to claim 3, characterized in that: The differential mechanism includes a coaxially arranged third sun gear and a third planet carrier, the third planet carrier is provided with at least two third planet gears, the circumferential side of the third planet gear is connected to the second inner ring gear, and the third sun gear is fixedly connected to the second planet carrier.

5. The single-motor coaxial reducer assembly according to claim 4, characterized in that: The first planetary gear is constantly meshed with the first sun gear, the first planetary gear is constantly meshed with the first inner ring gear, the second planetary gear is constantly meshed with the second sun gear, the second planetary gear is constantly meshed with the second inner ring gear, the third planetary gear is constantly meshed with the third sun gear, and the third planetary gear is constantly meshed with the second inner ring gear.

6. The single-motor coaxial reducer assembly according to claim 5, characterized in that: The third planet carrier is connected to the left tire via the left wheel transmission shaft, and the second inner gear ring is connected to the right tire via the right wheel transmission shaft.

7. The single-motor coaxial reducer assembly according to claim 1, characterized in that: The first inner gear ring is fixedly arranged, and the second inner gear ring is movably arranged.

8. A single-motor coaxial reducer assembly according to any one of claims 1 to 7, characterized in that: The first internal gear ring has only one number of teeth.

9. A single-motor coaxial reducer assembly according to any one of claims 1 to 7, characterized in that: The first inner gear ring is a duplex gear ring.

10. The single-motor coaxial reducer assembly according to claim 9, characterized in that: The number of teeth in the rear half of the first inner gear ring is greater than the number of teeth in the front half.

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