CN118665153A - Wheel hub motor drive system and vehicle - Google Patents

Abstract

The application provides an in-wheel motor driving system and a vehicle. In this in-wheel motor drive system, the motor is arranged side by side in the axial direction with the planetary gear reduction mechanism and the brake mechanism, and the planetary gear reduction mechanism overlaps in the radial direction with the brake caliper assembly of the brake mechanism. The axial length of the entire in-wheel motor drive system can thus be determined by the motor and the brake mechanism, that is to say the axial length of the entire in-wheel motor drive system is substantially equal to the sum of the axial lengths of both the motor and the brake mechanism. Thus, the overall size of the system, particularly the axial size, can be reduced as compared with the existing in-wheel motor drive system, and further the adverse effect of the axial length of the in-wheel motor drive system on the size of the wheel and the structural layout of the vehicle can be reduced.

Description

Wheel hub motor drive system and vehicle

Technical Field

The present application relates to the field of vehicles such as electric vehicles, and in particular to a wheel hub motor drive system for a vehicle and a vehicle including the wheel hub motor drive system.

Background Art

In the prior art, new energy vehicles such as electric vehicles still mainly use a drive system consisting of a central motor, a clutch, a transmission and a differential, which results in too many components in the drive system and a long torque transmission path, resulting in high power loss and low efficiency in the drive system, which seriously affects the driving distance of new energy vehicles. Therefore, technicians have developed a wheel hub motor drive system with a shorter torque transmission path to overcome the above problems.

The existing wheel hub motor drive system integrates the motor, the speed change mechanism and the wheel brake mechanism, etc. However, the layout of these components in the existing wheel hub motor drive system is not reasonable, resulting in the size of the entire wheel hub motor drive system (especially the axial size) being too large, thus occupying too much space, which in turn has an adverse effect on the size of the wheel including the wheel hub motor drive system and the structural layout of the vehicle (such as the layout of the suspension system).

Summary of the invention

This application is made based on the defects of the above-mentioned prior art. One purpose of this application is to provide a new wheel hub motor drive system, which can reduce the overall size of the system compared with the existing wheel hub motor drive system, especially shorten the axial size, thereby reducing the adverse effects of the wheel hub motor drive system on the size of the wheel and the structural layout of the vehicle. Another purpose of this application is to provide a vehicle including the above-mentioned wheel hub motor drive system.

In order to achieve the above-mentioned invention objectives, this application adopts the following technical solutions.

The present application provides a wheel hub motor drive system as follows, which has axial, radial and circumferential directions, and the wheel hub motor drive system includes:

An output shaft, one axial end of which is used to be fixed to the wheel hub;

A motor including a stator and a rotor;

a planetary gear reduction mechanism, which is located on one side of the axial direction relative to the motor and arranged side by side with the motor in the axial direction, the planetary gear reduction mechanism comprising a sun gear and a planetary gear carrier, the sun gear is drivingly connected to the rotor, and the planetary gear carrier is drivingly connected to the output shaft; and

A brake mechanism is located on one side of the axial direction relative to the motor and is arranged side by side with the motor in the axial direction, the brake mechanism includes a brake disc and a brake caliper assembly, the brake disc is torsionally mounted on the output shaft, the brake caliper assembly can controllably generate friction torque with the brake disc, the brake caliper assembly overlaps with the planetary gear reduction mechanism in the radial direction, and the brake disc overlaps with the planetary gear reduction mechanism in the axial direction.

In an optional solution, the brake caliper assembly includes an axially opposite side portion located on the axially opposite side of the brake disc, the axially opposite side portion is located radially outside the planetary gear reduction mechanism, and the axially opposite side portion overlaps with the planetary gear reduction mechanism in the radial direction.

In another optional solution, it further includes a housing assembly, the housing assembly defines a first space and a second space separated from each other, the motor is at least partially received and installed in the first space, the planetary gear reduction mechanism is at least partially received and installed in the second space, and the brake mechanism is at least partially located outside the housing assembly.

A radially outer portion of the first space and the brake mechanism are adjacent to each other in the axial direction, and a radially inner portion of the first space and the brake mechanism are sandwiched by the second space.

In another optional solution, the brake caliper assembly is mounted on a housing assembly.

In another optional solution, the motor is a radial magnetic field motor, and the motor further includes a rotor support and a motor shaft, the motor shaft extends from the first space to the second space, and the rotor is indirectly connected to the sun gear via the rotor support and the motor shaft; or

The motor is an axial flow motor, and further comprises a motor shaft, wherein the motor shaft extends from the first space to the second space, and the rotor is indirectly coupled to the sun gear via the motor shaft.

In another optional solution, a support bearing is further included, and the support bearing is located between the housing assembly and the motor shaft.

In another optional solution, it also includes a steering knuckle and a wheel bearing,

The output shaft includes a first flange portion and a first shaft portion fixed to each other, the first shaft portion extends from the first flange portion toward the other side of the axial direction, and the first flange portion is used to be fixed to the wheel hub.

The steering knuckle comprises a second flange portion and a second shaft portion fixed to each other, the second flange portion is fixed to the housing assembly, and the second shaft portion extends from the second flange portion toward one axial side and is inserted into the first shaft portion.

The wheel bearing is located between the first shaft portion and the second shaft portion.

In another optional scheme, the planetary gear reduction mechanism includes a first planetary row and a second planetary row, the first planetary row includes a first sun gear and a first planetary wheel carrier, the second planetary row includes a second sun gear and a second planetary wheel carrier, the first sun gear is drivingly connected to the rotor, the first planetary wheel carrier is drivingly connected to the second sun gear, and the second planetary wheel carrier is drivingly connected to the output shaft.

In another optional solution, an inverter assembly for the motor is further included, and the inverter assembly is located radially outside the planetary gear reduction mechanism and is arranged side by side with the other axial side portion of the brake caliper assembly in the circumferential direction.

The present application also provides a vehicle as follows, comprising the hub motor drive system described in any one of the above technical solutions.

By adopting the above technical solution, the present application provides a novel wheel hub motor drive system and a vehicle including the wheel hub motor drive system. The wheel hub motor drive system includes an output shaft, a motor, a planetary gear reduction mechanism and a brake mechanism assembled together. The planetary gear reduction mechanism is arranged side by side with the motor in the axial direction and is used to transmit torque between the motor and the output shaft. The brake mechanism is arranged side by side with the motor in the axial direction and includes a brake disc and a brake caliper assembly. The brake disc is mounted on the output shaft in a torsionally fixed manner, and the brake caliper assembly can generate friction torque with the brake disc in a controlled manner. The brake caliper assembly overlaps with the planetary gear reduction mechanism in the radial direction, and the brake disc overlaps with the planetary gear reduction mechanism in the axial direction. It can be understood that the radial overlap of the brake caliper assembly and the planetary gear reduction mechanism here means that, when observed along at least one radial direction, the projections of the brake caliper assembly and the planetary gear reduction mechanism on the projection plane perpendicular to the radial direction at least partially overlap.

In this way, the motor, the planetary gear reduction mechanism and the brake mechanism are arranged side by side in the axial direction, and the brake caliper assembly of the planetary gear reduction mechanism and the brake mechanism overlaps in the radial direction, so the axial length of the entire wheel hub motor drive system can be determined by the motor and the brake mechanism, that is, the axial length of the entire wheel hub motor drive system is basically equal to the sum of the axial lengths of the motor and the brake mechanism. Therefore, compared with the existing wheel hub motor drive system, the overall size of the system can be reduced, especially the axial size can be shortened, and then the adverse effect of the axial length of the wheel hub motor drive system on the size of the wheel and the structural layout of the vehicle (the layout of the suspension system) can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic cross-sectional view showing a wheel hub motor drive system according to a first embodiment of the present application.

FIG. 1B is a perspective schematic diagram showing the wheel hub motor drive system in FIG. 1A .

FIG. 2A is a schematic cross-sectional view showing a wheel hub motor drive system according to a second embodiment of the present application.

FIG. 2B is a perspective schematic diagram showing the wheel hub motor drive system in FIG. 2A .

FIG. 2C is a perspective schematic diagram showing a partial structure of the wheel hub motor drive system in FIG. 2A .

Description of Reference Numerals

1 output shaft; 11 first flange portion; 12 first shaft portion;

2 motor; 21 stator; 22 rotor; 23 rotor bracket; 24 motor shaft;

3 planetary gear reduction mechanism; 31 first sun gear; 32 first planetary gear; 33 first planetary gear carrier; 34 first ring gear; 35 second sun gear; 36 second planetary gear; 37 second planetary gear carrier; 38 second ring gear;

4 brake mechanism; 41 brake disc; 42 brake caliper assembly; 421 brake caliper housing; 422 brake piston; 423 brake lining;

5 housing assembly; S1 first space; S2 second space;

6 steering knuckle; 61 second flange portion; 62 second shaft portion;

7 wheel bearings;

8 Inverter components;

91 a first support bearing; 92 a second support bearing;

A is axial; R is radial.

DETAILED DESCRIPTION

The exemplary embodiments of the present application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not intended to exhaust all feasible methods of the present application, nor to limit the scope of the present application.

In the present application, the wheel hub motor drive system includes an output shaft, and other components are arranged coaxially with the output shaft. Unless otherwise specified, "axial", "radial" and "circumferential" refer to the axial, radial and circumferential directions of the output shaft, respectively. "Axial side" refers to the left side in Figures 1A and 2A, and "axial other side" refers to the right side in Figures 1A and 2A. "Radially outer side" refers to the side radially away from the central axis of the output shaft, and "radially inner side" refers to the side radially close to the central axis of the output shaft.

In this application, "drive connection" refers to the connection between two components in a way that can transmit torque. "Direct drive connection" refers to the drive connection between two components using direct connection methods such as splines or direct fixation; "indirect drive connection" refers to the drive connection between two components through indirect connection methods such as connectors or other transmission mechanisms.

In the present application, two components overlapping in a certain direction means that when viewed along the direction, there is at least a partial overlap between the projections of the two components on a projection plane perpendicular to the direction.

The following describes a wheel hub motor drive system according to a first embodiment of the present application in conjunction with the accompanying drawings.

(In-wheel motor drive system according to the first embodiment of the present application)

As shown in Figures 1A and 1B, the wheel hub motor drive system according to the first embodiment of the present application includes an output shaft 1, a motor 2, a planetary gear reduction mechanism 3, a brake mechanism 4, a housing assembly 5, a steering knuckle 6, a wheel bearing 7, and support bearings 91, 92 assembled together. In this embodiment, the axial size of the wheel hub motor drive system is basically determined by the motor 2 and the brake mechanism 4 arranged side by side in the axial direction A. The planetary gear reduction mechanism 3 is located radially inside the brake caliper assembly 42 of the brake mechanism 4 and overlaps with the other axial side of the brake caliper assembly 42 in the radial direction R, and the axial length of the wheel hub motor drive system will not be additionally increased due to the planetary gear reduction mechanism 3.

In the present embodiment, as shown in FIG. 1A and FIG. 1B , the output shaft 1 is a hollow flange shaft extending along the axial direction A. Specifically, the output shaft 1 includes a first flange portion 11 and a first shaft portion 12 formed as one body. The first flange portion 11 extends from one axial side end of the first shaft portion 12 toward the radial outside, and the first flange portion 11 extends continuously along the entire circumference. The first flange portion 11 is formed with a plurality of mounting holes, and mounting members such as hub bolts passing through the plurality of mounting holes can fix the first flange portion 11 to the wheel hub of the vehicle wheel, and the brake disc 41 of the brake mechanism 4 can be directly mounted on the first flange portion 11 in a torsion-resistant manner. The first shaft portion 12 extends linearly from the inner circumference of the first flange portion 11 toward the other axial side, and the first shaft portion 12 is directly transmission-connected to the second planetary wheel carrier 37 of the planetary gear reduction mechanism 3.

In the present embodiment, the motor 2 is an axial flow motor (or axial magnetic field/flux motor). Specifically, as shown in FIG1A , the motor 2 includes a stator 21, a rotor 22 and a motor shaft 24. The stator 21 is fixed to the housing assembly 5, and a cooling channel may be provided between the stator 21 and the housing assembly 5 to reduce the temperature of the stator 21 during operation of the motor 2. The rotor 22 is opposite to the stator 21 in the axial direction A, and the rotor 22 can rotate relative to the stator 21. The rotor 22 is also directly fixed to the motor shaft 24, so that the rotor 22 and the motor shaft 24 are directly connected in transmission. Further, the first sun gear 31 of the planetary gear reduction mechanism 3 can be formed as one piece with the motor shaft 24 and be located at one axial end of the motor shaft 24.

In this embodiment, the planetary gear reduction mechanism 3 can transmit the torque from the motor 2 to the output shaft 1. Specifically, as shown in FIG1A , the planetary gear reduction mechanism 3 includes a first planetary row and a second planetary row, the second planetary row and the first planetary row are arranged side by side in the axial direction A, and the second planetary row is located on one side of the axial direction relative to the first planetary row.

The first planetary gear row includes a first sun gear 31, a first planetary gear 32, a first planetary gear carrier 33 and a first gear ring 34 assembled together. As described above, a gear tooth is formed at one axial end of the motor shaft 24 of the motor 2 to constitute the first sun gear 31 of the planetary gear reduction mechanism 3, that is, the first sun gear 31 is formed as a whole with the motor shaft 24. A plurality of first planetary gears 32 are located radially outside the first sun gear 31 and are evenly distributed along the circumference. Each first planetary gear 32 is always meshed with the first sun gear 31, so that as the first sun gear 31 rotates, each first planetary gear 32 can rotate around its own central axis and revolve around the first sun gear 31. The first planetary gear carrier 33 is located radially outside the first sun gear 31, and a plurality of first planetary gears 32 are mounted on the first planetary gear carrier 33. The first planetary gear carrier 33 is directly connected to the second sun gear 35 of the second planetary gear row. As the plurality of first planetary gears 32 revolve, the first planetary gear carrier 33 can be driven to rotate and then the second sun gear 35 can be driven to rotate. The first ring gear 34 is located radially outside the first planetary gears 32 and fixed to the housing assembly 5 . An orbit for the first planetary gears 32 to revolve is formed between the first ring gear 34 and the first sun gear 31 . The first ring gear 34 is always meshed with the first planetary gears 32 .

The second planetary gear row includes a second sun gear 35, a second planetary gear 36, a second planetary gear carrier 37 and a second gear ring 38 assembled together. As described above, the second sun gear 35 is directly connected to the first planetary gear carrier 33 of the first planetary gear row. A plurality of second planetary gears 36 are located radially outside the second sun gear 35 and are evenly distributed along the circumference. Each second planetary gear 36 is always meshed with the second sun gear 35, so that as the second sun gear 35 rotates, each second planetary gear 36 can rotate around its own central axis and revolve around the second sun gear 35. The second planetary gear carrier 37 is located radially outside the second sun gear 35, and a plurality of second planetary gears 36 are mounted on the second planetary gear carrier 37. The second planetary gear carrier 37 can be directly connected to the output shaft 1 through direct fixing or spline structure. As the plurality of second planetary gears 36 revolve, the second planetary gear carrier 37 can be driven to rotate and then the output shaft 1 can be driven to rotate. The second ring gear 38 is located radially outside the second planetary gears 36 and fixed to the housing assembly 5 . An orbit for the second planetary gears 36 to revolve is formed between the second ring gear 38 and the second sun gear 35 . The second ring gear 38 is always meshed with the second planetary gears 36 .

In this embodiment, the brake mechanism 4 is a caliper-disc brake mechanism, which can generate a friction torque to prevent the wheel from rotating. Specifically, as shown in FIG. 1A and FIG. 1B , the brake mechanism 4 includes a brake disc 41 and a brake caliper assembly 42 assembled together. The brake disc 41 can be mounted on the first flange portion 11 of the output shaft 1 in a torsion-resistant manner, so that the friction torque generated by the brake disc 41 and the brake caliper assembly 42 can be transmitted to the output shaft 1. The brake caliper assembly 42 includes a brake caliper housing 421, a brake piston 422 and a brake lining 423. The brake caliper housing 421 is fixed to the housing assembly 5, and the brake piston 422 can be located in a cylinder chamber formed in the brake caliper housing 421. The brake piston 422 can be driven to move by a power source, and then the brake piston 422 drives the brake lining 423 to clamp the brake disc 41, thereby generating a friction torque to prevent the wheel from rotating, thereby achieving braking.

Further, the brake caliper assembly 42 includes an axial one side portion located at one axial side relative to the brake disc 41 and an axial other side portion located at the other axial side relative to the brake disc 41. The axial other side portion is located radially outside the planetary gear reduction mechanism 3, and the axial other side portion and the planetary gear reduction mechanism 3 are substantially completely overlapped in the radial direction R. In this embodiment, both sides of the brake disc 41 have a brake piston 422 and a brake lining 423, so the axial one side portion and the axial other side portion of the brake disc 41 each include a brake piston 422 and a brake lining 423.

In this embodiment, as shown in FIG. 1A and FIG. 1B , the housing assembly 5 is formed as a whole in a cylindrical shape. Specifically, the housing assembly 5 may include a housing body and at least one cover assembled together. Further, the housing assembly 5 defines a first space S1 and a second space S2 separated from each other. As shown in FIG. 1A , the radially outer portion of the first space S1 and the axially other side portion of the brake caliper assembly 42 are adjacent to each other in the axial direction A, and the radially inner portion of the first space S1 and the second space S2 are adjacent in the axial direction A. Most of the second space S2 overlaps with the axially other side portion of the brake caliper assembly 42 in the radial direction R. The stator 21 and the rotor 22 of the motor 2 are accommodated and installed in the first space S1, and the motor shaft 24 extends from the position of the first space S1 to the position of the second space S2 in the axial direction A. At least a part of the structure of the planetary gear reduction mechanism 3 is accommodated and installed in the second space S2. The entire brake mechanism 4 is located outside the housing assembly 5. In addition, the outer peripheral portion of the brake disc 41 can be clamped by the brake caliper assembly 42 to achieve braking. The brake disc 41 can form a bending structure so that the outer periphery of the brake disc 41 can be located on the other axial side relative to the inner periphery, so that the inner periphery of the brake disc 41 can be located on one axial side of the planetary gear reduction mechanism 3, and the outer periphery of the brake disc 41 can be located on the radial outside of the planetary gear reduction mechanism 3 and overlap with the planetary gear reduction mechanism 3 in the radial direction R.

In the present embodiment, as shown in FIG. 1A and FIG. 1B , the steering knuckle 6 is formed as a flange shaft extending along the axial direction A. Specifically, the steering knuckle 6 includes a second flange portion 61 and a second shaft portion 62 formed as one body. The second flange portion 61 extends from the other axial side end of the second shaft portion 62 toward the radial outside, and the second flange portion 61 extends continuously along the circumferential direction over the entire circumference. The second flange portion 61 is formed with a plurality of mounting holes, and mounting members such as bolts passing through the plurality of mounting holes enable the second flange portion 61 to be mounted together with the suspension system of the vehicle. The second shaft portion 62 extends linearly from the inner circumference of the second flange portion 61 toward one axial side. The second shaft portion 62 extends into the interior of the first shaft portion 12 of the output shaft 1.

In this embodiment, as shown in FIG1A , the wheel bearing 7 may be a double-row tapered roller bearing. The wheel bearing 7 includes an inner ring, an outer ring, and rolling elements, wherein the inner ring is fixed to the steering knuckle 6, the outer ring is fixed to the output shaft 1, and the rolling elements are located between the inner ring and the outer ring. Thus, the second shaft portion 62 of the steering knuckle 6 can support the first shaft portion 12 of the output shaft 1 through the wheel bearing 7.

In this embodiment, as shown in FIG. 1A , in order to support the motor shaft 24, a first support bearing 91 and a second support bearing 92 are provided between the motor shaft 24 and the housing assembly 5. The first support bearing 91 and the second support bearing 92 may both be deep groove ball bearings. The first support bearing 91 and the second support bearing 92 are spaced apart from each other and are respectively located on both sides of the axial direction of the rotor 22.

In this way, in the wheel hub motor drive system according to the first embodiment of the present application, the following working modes can be implemented.

In the first working mode, the torque is transmitted toward the wheel hub through the motor 2 to drive the wheel to rotate. In this working mode, the transmission path of the torque from the motor 2 is as follows: rotor 22→motor shaft 24→first sun gear 31→first planetary gear 32→first planetary gear carrier 33→second sun gear 35→second planetary gear 36→second planetary gear carrier 37→output shaft 1→wheel hub.

In the second working mode, braking energy recovery is performed during vehicle braking. In this working mode, the transmission path of the torque from the wheel hub is as follows: wheel hub→output shaft 1→second planetary carrier 37→second planetary gear 36→second sun gear 35→first planetary carrier 33→first planetary gear 32→first sun gear 31→motor shaft 24→rotor 22.

In the third working mode, the friction torque generated by the brake mechanism 4 during vehicle braking is transmitted to the wheel hub, and the kinetic energy of the vehicle is converted into thermal energy of the brake mechanism 4. In this working mode, the transmission path of the friction torque from the brake mechanism 4 is as follows: brake disc 41 → output shaft 1 → wheel hub.

In the wheel hub motor drive system according to the first embodiment of the present application, the motor 2 and the brake mechanism 4 are arranged side by side in the axial direction A, and other components are substantially completely overlapped with the motor 2 and the brake mechanism 4 in the radial direction R, so the axial length of the entire wheel hub motor drive system can be determined by the motor 2 and the brake mechanism 4, thereby reducing the axial dimension compared with the wheel hub motor drive system of the prior art, and reducing the adverse effects of the axial dimension of the wheel hub motor drive system on the size of the wheel and the overall layout of the vehicle (the layout of the suspension system). In particular, the planetary gear reduction mechanism 3 does not additionally increase the axial length of the entire wheel hub motor drive system.

The following describes a wheel hub motor drive system according to a second embodiment of the present application in conjunction with the accompanying drawings.

(In-wheel motor drive system according to the second embodiment of the present application)

The structure of the wheel hub motor drive system according to the second embodiment of the present application is substantially the same as the structure of the wheel hub motor drive system according to the first embodiment of the present application, and the differences between the two are mainly described below.

In the present embodiment, as shown in FIG. 2A to FIG. 2C , the motor 2 is a radial magnetic field motor. As shown in FIG. 2A , specifically, compared with the axial flow motor in the first embodiment, in the present embodiment, the motor 2 further includes a rotor support 23. The stator 21 is fixed to the housing assembly 5, and a cooling jacket may be provided between the stator 21 and the housing assembly 5 to reduce the temperature of the stator 21 during operation of the motor 2. The rotor 22 is located radially inside the stator 21 and opposite to the stator 21 in the radial direction R, and the rotor 22 can rotate relative to the stator 21. The rotor support 23 is located radially inside the rotor 22 and fixed to the rotor 22, and the rotor support 23 is also fixed to the motor shaft 24, so that the rotor 22 and the motor shaft 24 are indirectly coupled via the rotor support 23.

In this embodiment, as shown in FIGS. 2A to 2C , the wheel hub motor drive system further includes an inverter assembly 8 for the motor 2, and the inverter assembly 8 includes necessary electronic components and circuit connection structures. The inverter assembly 8 is located radially outside the planetary gear reduction mechanism 3. In addition, the inverter assembly 8 and the axially other side portion of the brake caliper assembly 42 are arranged side by side in the circumferential direction, that is, the inverter assembly 8 and the axially other side portion of the brake caliper assembly 42 are located at the same position on the axis A. In this embodiment, the inverter assembly 8 is located outside the second space S2 and is installed in a groove structure with an open structure formed by the housing assembly 5.

By adopting the above structure, the same effect as the first embodiment can be achieved. Moreover, even if the inverter assembly 8 is provided, the axial dimension of the entire wheel hub motor drive system will not be increased. Furthermore, the inverter assembly 8 can share a cooling system with the motor 2.

The present application is not limited to the above embodiments, and those skilled in the art can make various modifications to the above embodiments of the present application under the guidance of the present application without departing from the scope of the present application. In addition, the following description is also made.

i. The present application also provides a vehicle including the above-mentioned wheel hub motor drive system, which may be an electric vehicle with more than two wheels. In an optional example of the vehicle according to the present application, the vehicle includes four wheels, and the wheel hub motor drive system is installed in two or four wheels.

ii. It can be understood that in order to achieve the necessary separation and sealing effects, a sealing assembly and a sealing ring can be provided as required in the hub motor drive system of the present application.

iii. In the hub motor drive system of the present application, the brake mechanism 4 and the planetary gear reduction mechanism 3 are located between the hub or spoke and the motor 2 in the axial direction A. In addition, the brake disc 41 of the brake mechanism 4 is mounted on the output shaft 1 and thus has the same speed as the output shaft 1.

iv. It can be understood that in the drawings corresponding to the first embodiment, the components of the housing assembly 5 and the stator 21 are shown as a whole for the sake of simplicity. In addition, in each embodiment of the present application, the housing assembly 5 can be used to separate the first space S1 and the second space S2, and the brake mechanism 4 is located outside the housing assembly 5. The first space S1 and the second space S2 can be closed spaces.

v. It can be understood that the second shaft portion 62 of the steering knuckle 62 is inserted into the first shaft portion 11 of the output shaft 1, so that the first shaft portion 12 of the output shaft 1 and the second shaft portion 62 of the steering knuckle 6 partially overlap in the radial direction R, and the overall length of both the output shaft 1 and the steering knuckle 6 in the axial direction A may not exceed or slightly exceed the axial length limited by the motor 2 and the brake mechanism 4.

Claims (10)

1. A wheel hub motor drive system having axial (A), radial (R) and circumferential directions, characterized in that the wheel hub motor drive system comprises: An output shaft (1), one axial end of which is used to be fixed to a wheel hub; A motor (2) comprising a stator (21) and a rotor (22); a planetary gear reduction mechanism (3), which is located on one side of the axial direction relative to the motor (2) and is arranged side by side with the motor (2) in the axial direction (A), the planetary gear reduction mechanism (3) comprising a sun gear (31) and a planetary gear carrier (37), the sun gear (31) being drivingly connected to the rotor (22), and the planetary gear carrier (37) being drivingly connected to the output shaft (1); and A brake mechanism (4) is located on one side of the axial direction relative to the motor (2) and is arranged side by side with the motor (2) in the axial direction (A), the brake mechanism (4) comprising a brake disc (41) and a brake caliper assembly (42), the brake disc (41) being torsionally mounted on the output shaft (1), the brake caliper assembly (42) being controllably capable of generating friction torque with the brake disc (41), the brake caliper assembly (42) overlapping with the planetary gear reduction mechanism (3) in the radial direction (R), and the brake disc (41) overlapping with the planetary gear reduction mechanism (3) in the axial direction (A). 2. The hub motor drive system according to claim 1 is characterized in that the brake caliper assembly (42) includes an axially opposite side portion located on the axially opposite side relative to the brake disc (41), the axially opposite side portion being located radially outside the planetary gear reduction mechanism (3), and the axially opposite side portion overlaps with the planetary gear reduction mechanism (3) in the radial direction (R). 3. The wheel hub motor drive system according to claim 2, characterized in that it also includes a housing assembly (5), wherein the housing assembly (5) defines a first space (S1) and a second space (S2) separated from each other, wherein the motor (2) is at least partially received and installed in the first space (S1), the planetary gear reduction mechanism (3) is at least partially received and installed in the second space (S2), and the brake mechanism (4) is at least partially located outside the housing assembly. The radially outer portion of the first space (S1) and the brake mechanism (4) are adjacent to each other in the axial direction (A), and the radially inner portion of the first space (S1) and the brake mechanism (4) are sandwiched by the second space (S2). 4. The wheel hub motor drive system according to claim 3, characterized in that the brake caliper assembly (42) is mounted on the housing assembly (5). 5. The wheel hub motor drive system according to claim 3, characterized in that: The motor (2) is a radial magnetic field motor, and the motor (2) further comprises a rotor support (23) and a motor shaft (24), the motor shaft (24) extends from the first space (S1) to the second space (S2), and the rotor (22) is indirectly transmission-connected to the sun gear (31) via the rotor support (23) and the motor shaft (24); or The motor (2) is an axial flow motor, and the motor (2) further comprises a motor shaft (24), wherein the motor shaft (24) extends from the first space (S1) to the second space (S2), and the rotor (22) is indirectly connected to the sun gear (31) via the motor shaft (24). 6. The wheel hub motor drive system according to claim 5, characterized in that it also includes a support bearing (91, 92), wherein the support bearing (91, 92) is located between the housing assembly (5) and the motor shaft (24). 7. The wheel hub motor drive system according to any one of claims 3 to 6, characterized in that it also comprises a steering knuckle (6) and a wheel bearing (7), The output shaft (1) comprises a first flange portion (11) and a first shaft portion (12) fixed to each other, the first shaft portion (12) extending from the first flange portion (11) toward the other side of the axial direction, and the first flange portion (11) is used to be fixed to the wheel hub. The steering knuckle (6) comprises a second flange portion (61) and a second shaft portion (62) fixed to each other, the second flange portion (61) being fixed to the housing assembly (5), and the second shaft portion (62) extending from the second flange portion (61) toward one axial side and inserted into the first shaft portion (12). The wheel bearing (7) is located between the first shaft portion (12) and the second shaft portion (62). 8. The hub motor drive system according to any one of claims 1 to 6, characterized in that the planetary gear reduction mechanism (3) includes a first planetary gear row and a second planetary gear row, the first planetary gear row includes a first sun gear (31) and a first planetary gear carrier (33), the second planetary gear row includes a second sun gear (35) and a second planetary gear carrier (37), the first sun gear (31) is transmission-connected to the rotor (22), the first planetary gear carrier (33) is transmission-connected to the second sun gear (35), and the second planetary gear carrier (37) is transmission-connected to the output shaft (1). 9. The wheel hub motor drive system according to any one of claims 1 to 6, characterized in that it also includes an inverter assembly (8) for the motor (2), wherein the inverter assembly (8) is located radially outside the planetary gear reduction mechanism (3) and is arranged side by side with the other axial side portion of the brake caliper assembly (42) in the circumferential direction. 10. A vehicle, characterized by comprising the wheel hub motor drive system according to any one of claims 1 to 9.