CN116409138A - In-wheel motor drive system and motor vehicle - Google Patents

Abstract

The application provides an in-wheel motor driving system and a motor vehicle. In the in-wheel motor driving system, a steering knuckle is taken as a reference, a brake system and a wheel bearing are positioned on the opposite side of the driving mechanism, a brake caliper mechanism of the brake system and an outer ring of the wheel bearing are detachably arranged on the steering knuckle, and an inner ring of the wheel bearing is in transmission connection with an output shaft of the driving system through a spline. The above structural design is beneficial to the adaptation and disassembly of the steering knuckle and other structures of the in-wheel motor driving system and the different braking systems and wheel bearings, that is to say, the in-wheel motor driving system according to the application can adapt to the wheels with the different braking systems and wheel bearings without structural adjustment. Thereby, the versatility of the in-wheel motor drive system of the present application is improved.

Description

In-wheel motor drive system and motor vehicle

technical field

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

Background technique

In the prior art, new energy motor vehicles such as electric vehicles still mainly use a central drive motor, clutch, transmission and differential to form a drive system for transmitting torque that drives the wheels, which results in a relatively narrow transmission path for torque. Long, so that the power loss of the drive system is high and the efficiency is low, which seriously affects the driving distance of new energy vehicles. Therefore, technicians have developed an in-wheel motor drive system with a shorter torque transmission path to overcome the above-mentioned problems.

However, the existing in-wheel motor drive system generally integrates the drive motor, transmission, and the braking system and wheel bearing of the wheel. The braking system needs to change the structure of the entire hub motor drive system. Therefore, the versatility of the existing in-wheel motor drive system is poor.

Contents of the invention

The present application is made based on the above-mentioned shortcomings of the prior art. An object of the present application is to provide a novel in-wheel motor drive system that can be easily adapted to wheels with different wheel bearings and braking systems, thus improving the versatility of the in-wheel motor system. Another object of the present application is to provide a motor vehicle comprising the above in-wheel motor drive system.

In order to realize the purpose of the above invention, the present application adopts the following technical solutions.

The present application provides a hub motor drive system as follows, the hub motor drive system comprising:

a steering knuckle, the steering knuckle includes a mounting portion;

A driving mechanism, the driving mechanism is detachably mounted on the installation part, and includes a motor assembly, a planetary gear reduction mechanism, a housing assembly and an output shaft, and the motor assembly and the output shaft pass through the planetary gear reduction mechanism Always transmission coupling, the output shaft passes through the installation part along its axial direction and can rotate relative to the installation part, and the planetary gear reduction mechanism is located in the first part surrounded by the housing assembly and the installation part. in the installation space;

A wheel bearing, the wheel bearing includes an inner ring and an outer ring, the outer ring is detachably mounted on the mounting part, the inner ring is connected to the output shaft through a spline transmission; and

A braking system, the braking system includes a brake disc and a brake caliper mechanism, the brake disc is relatively fixed to the output shaft, and the brake caliper mechanism is detachably mounted on the installation part,

In the axial direction, the driving mechanism is located on one side of the installation part, and the wheel bearing and the braking system are located on the other side of the installation part.

In an optional solution, the driving mechanism includes a stator, a rotor, and a motor shaft, and the planetary gear reduction mechanism includes a sun gear, a planetary gear, a planetary gear carrier, and a ring gear,

The rotor can rotate relative to the stator, the rotor is coupled with the sun gear through the motor shaft, the output shaft is coupled with the planetary gear carrier, and the ring gear is fixed with the mounting part ,

The motor shaft is arranged coaxially with the output shaft.

In another optional solution, the brake disc is fixed to the inner ring, and the brake disc is arranged coaxially with the output shaft.

In another optional solution, a second installation space is formed inside the housing assembly, and the motor assembly is installed in the second installation space.

In another optional solution, the mounting part is formed with multiple sets of mounting holes penetrating along the axial direction, and the brake caliper mechanism is installed through any set of the multiple sets of mounting holes. The connecting piece of the hole is fixedly connected with the installation part.

In another optional solution, the in-wheel motor drive system further includes a motor bearing and a support bearing, the motor bearing is located between the motor shaft and the housing assembly, and the support bearing is located at the output between the shaft and the mounting part.

In another optional solution, the steering knuckle further includes a bending part, a first pivoting part and a second pivoting part, the bending part protrudes from the mounting part, and the first pivoting part The rotating part is fixed to the bending part, and the second pivot part is fixed to the installation part.

The present application also provides the following motor vehicle, which includes the in-wheel motor drive system described in any one of the above technical solutions.

In an optional solution, the motor vehicle includes wheels, the installation parts of the wheel bearings, the braking system and the steering knuckle are located inside the wheels, and the bending part of the steering knuckle A portion extends to the outside of the wheel.

In another optional solution, the inner ring is fixed to the hub of the wheel.

By adopting the above technical solution, the present application provides a novel in-wheel motor drive system and a motor vehicle including the in-wheel motor drive system. The hub motor driving system includes a steering knuckle, a driving mechanism, a wheel bearing and a braking system. The steering knuckle includes a mounting part, and the driving mechanism is detachably mounted on the mounting part. The driving mechanism includes a motor assembly, a planetary gear reduction mechanism, a housing assembly and an output shaft. The motor assembly and the output shaft are always connected by transmission through the planetary gear reduction mechanism. The output shaft passes through the installation part along its axial direction and can rotate relative to the installation part. The planetary gear reduction mechanism is installed in the installation space surrounded by the housing assembly and the installation part Inside. The wheel bearing includes an inner ring and an outer ring, the outer ring is detachably mounted on the mounting part, and the inner ring is always connected with the output shaft through a spline. The brake system includes a brake disc and a brake caliper mechanism, the brake disc and the output shaft are relatively fixed, and the brake caliper mechanism is detachably mounted on the installation part. In the axial direction, the driving mechanism is located on one side of the installation part, and the wheel bearing and braking system are located on the other side of the installation part.

In this way, based on the steering knuckle, the braking system and the wheel bearing are located on the opposite side of the driving mechanism, the brake caliper mechanism of the braking system and the outer ring of the wheel bearing are detachably installed on the steering knuckle, and the inner ring of the wheel bearing It is connected with the output shaft of the drive system through spline transmission. The above structural design is beneficial to adapt and disassemble the steering knuckle and other structures of the in-wheel motor drive system of the present application and different braking systems and wheel bearings, that is to say, the in-wheel motor drive system of the present application does not need to be structurally adjusted. It is possible to adapt wheels with different braking systems and wheel bearings. Thus, the versatility of the in-wheel motor driving system of the present application is improved. Moreover, since the planetary gear reduction mechanism uses the steering knuckle as a part of its housing, a part of the housing originally used as the planetary gear reduction mechanism is omitted, thereby reducing the axial length of the in-wheel motor drive system of the present application.

Description of drawings

Fig. 1 is a schematic perspective view showing an assembly of an in-wheel motor drive system and a wheel according to an embodiment of the present application.

FIG. 2 is a schematic cross-sectional view showing the assembly in FIG. 1 .

Fig. 3 is a schematic cross-sectional view showing the in-wheel motor driving system in Fig. 1 , where the braking system is omitted.

FIG. 4 is a schematic perspective view showing the steering knuckle of the in-wheel motor drive system in FIG. 1 .

FIG. 5 is another schematic perspective view showing the steering knuckle of the in-wheel motor drive system in FIG. 1 .

FIG. 6 is a schematic cross-sectional view showing a partial structure of the drive mechanism of the in-wheel motor drive system in FIG. 1 .

Explanation of reference signs

WH Wheels HU Wheels TI Tires

DR hub motor drive system

1 steering knuckle 11 mounting part 11h through hole 11h1 first mounting hole 11h2 second mounting hole 11h3 third mounting hole 12 bending part 13 first pivoting part 14 second pivoting part

2 Driving mechanism 21 Motor assembly 211 Stator 212 Rotor 213 Rotor bracket 214 Motor shaft 22 Planetary gear reduction mechanism 221 Sun gear 222 Planetary gear 223 Planetary carrier 224 Ring gear 23 Housing assembly 231 First housing 232 Second housing 24 Output Axis S1 first installation space S2 second installation space

3 wheel bearing 31 inner ring 32 outer ring 33 rolling body

4 brake system 41 brake disc

B1 motor bearing B2 support bearing

A axial R radial.

Detailed ways

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, but are not intended to exhaust all possible ways of the present application, nor are they used to limit the scope of the present application.

In the present application, the output shaft of the in-wheel motor drive system is a linearly extending solid shaft. Unless otherwise specified, "axial", "radial" and "circumferential" refer to the axial, radial and circumferential directions of the output shaft, respectively. "Axially one side" refers to the right side in FIGS. 2 , 3 and 6 , and "the other axial side" refers to the left side in FIGS. 2 , 3 and 6 . "Radial outer side" means the side radially away from the central axis of the output shaft, and "radial inner side" means the side radially closer to the central axis of the output shaft.

In this application, "transmission coupling" refers to the connection between two components in a manner capable of transmitting torque, including direct connection and indirect connection.

The structure of an in-wheel motor drive system according to an embodiment of the present application will be described below with reference to the accompanying drawings.

As shown in FIGS. 1 to 3 , an in-wheel motor driving system DR according to an embodiment of the present application includes a steering knuckle 1 , a driving mechanism 2 , a wheel bearing 3 and a braking system 4 assembled together. The installation part 11 of the steering knuckle 1 is located inside the wheel WH and is sleeved on the output shaft 24 of the drive mechanism 2. The drive mechanism 2 is installed on the installation part 11 and is located on one axial side of the installation part 11. The wheel bearing 3 and the brake The system 4 is installed on the installation part 11 and is located on the other side of the installation part 11 in the axial direction.

In this embodiment, as shown in FIGS. 2 to 5 , the steering knuckle 1 includes a mounting portion 11 , a bending portion 12 , a first pivoting portion 13 and a second pivoting portion 14 formed in one piece.

Specifically, as shown in FIGS. 4 and 5 , the mounting portion 11 is integrally formed in a substantially plate shape, which has one axial side and the other axial side perpendicular to the axial direction A. As shown in FIG. A through hole 11h penetrating in the axial direction is formed at a central portion of the mounting portion 11, and the output shaft 24 of the driving mechanism 2 is inserted through the through hole 11h. The through hole 11h may be formed as a stepped hole for mounting the support bearing B2 for supporting the output shaft 24 . Around the through hole 11h, the mounting part 11 is also formed with a first mounting hole 11h1 for mounting the drive mechanism 2, a second mounting hole 11h2 for mounting the outer ring 32 of the wheel bearing 3, and a hole for mounting the brake system 4. The third mounting hole 11h3 for the brake caliper mechanism.

As shown in FIG. 4 and FIG. 5 , the first installation hole 11h1 is a through hole penetrating along the axial direction A, and a plurality of first installation holes 11h1 are distributed along the circumferential direction. As shown in Figure 3, at least part of the first installation hole 11h1 can be a stepped hole, the small diameter part of the stepped hole is opened on one side of the axial direction of the installation part 11, and the large diameter part of the stepped hole is opened on the other side of the axial direction of the installation part 11. Open on one side. In this way, the large-diameter portion can be conveniently inserted into the small-diameter portion and the connecting piece in the corresponding mounting hole of the housing assembly 23 of the driving mechanism 2 , so that the driving mechanism 2 is detachably mounted on the mounting portion 11 .

As shown in FIG. 5 , the second installation hole 11h2 is a blind hole extending along the axial direction A, and a plurality of second installation holes 11h2 are distributed along the circumferential direction. Each second mounting hole 11h2 is open on the other axial side of the mounting portion 11 , and each second mounting hole 11h2 is closed on one axial side of the mounting portion 11 . In this way, the outer ring 32 of the wheel bearing 3 is detachably mounted on the installation part 11 by inserting the connecting piece in the second installation hole 11h2 and the corresponding installation hole of the outer ring 32 of the wheel bearing 3 .

As shown in FIG. 4 and FIG. 5 , the third mounting hole 11h3 is a through hole penetrating along the axial direction. A plurality of third mounting holes 11h3 are divided into two groups, the first group of third mounting holes 11h3 are two third mounting holes 11h3 located on the left side in FIG. 4 and the right side in FIG. 5 , and the second group of third mounting holes 11h3 These are the two third mounting holes 11h3 on the right side in FIG. 4 and the left side in FIG. 5 . Any set of third mounting holes 11h3 can be used to detachably mount the brake caliper mechanism of the braking system 4 on the mounting portion 11 , which can improve the flexibility of installing the steering knuckle 1 and the brake caliper mechanism of the braking system 4 .

Further, as shown in FIG. 4 and FIG. 5 , the bent portion 12 protrudes from the mounting portion 11 , and the bent portion 12 is formed by multiple bendings. As shown in FIG. 1 and FIG. 2 , a part of the bent portion 12 is located inside the tire TI, and another part of the bent portion 12 extends to the outside of the tire TI until the radial outside of the tire TI. The first pivoting portion 13 is fixed to the portion of the bending portion 12 that is located radially outside the tire TI, and the second pivoting portion 14 is fixed to the portion of the mounting portion 11 away from the bending portion 12 . The steering knuckle 1 can be rotatably connected with the suspension system of the motor vehicle through the first pivot point 13 and the second pivot point 14 (constituting a structure similar to a universal joint), so that the wheel WH can rotate around the wheel WH by the first pivot point 13 and the second pivot point 14 The axis defined by the second pivot point 14 rotates.

Further, as shown in FIGS. 2 and 3 , the shape of the steering knuckle 1 is configured to match the second housing 232 of the housing assembly 23 of the drive mechanism 2 , so that the steering knuckle 1 serves as the housing of the planetary gear reduction mechanism 22 A part of it, that is, the planetary gear reduction mechanism 22 is installed in the first installation space S1 surrounded by the steering knuckle 1 and the second housing 232 .

In this embodiment, as shown in FIG. 2 , FIG. 3 and FIG. 6 , the driving mechanism 2 is detachably mounted on the mounting part 11 and includes a motor assembly 21 , a planetary gear reduction mechanism 22 , a housing assembly 23 and an output shaft 24 . The motor assembly 21 and the output shaft 24 are always in transmission connection via the planetary gear reduction mechanism 22 , and the output shaft 24 passes through the installation part 11 of the steering knuckle 1 along the axial direction A and can rotate relative to the installation part 11 .

Specifically, as shown in FIGS. 2 and 3 , the motor assembly 21 is integrally installed in the second installation space S2 defined by the housing assembly 23 . The motor assembly 21 includes a stator 211 , a rotor 212 , a rotor bracket 213 and a motor shaft 214 . The stator 211 and the housing assembly 23 are fixed together, and a cooling jacket may be provided between the stator 211 and the housing assembly 23 to reduce the temperature of the stator 211 when the motor assembly 21 is working. The rotor 212 is located radially inside the stator 211 and is opposed to the stator 211 in the radial direction R, and the rotor 212 is rotatable relative to the stator 211 . The rotor bracket 213 is located on the radial inner side of the rotor 212 and is fixed together with the rotor 212 . The rotor bracket 213 is also fixed together with the motor shaft 214 , so that the rotor 212 and the motor shaft 214 are connected by transmission through the rotor bracket 213 .

As shown in FIG. 3 , the planetary gear reduction mechanism 22 is located in the first installation space S1 surrounded by the housing assembly 23 and the installation part 11 . The planetary reduction mechanism 22 includes a sun gear 221 , a planetary gear 222 , a planetary gear carrier 223 and a ring gear 224 . In this embodiment, gear teeth are formed on one end of the motor shaft 214 of the motor assembly 21 to constitute the sun gear 221 of the planetary gear reduction mechanism 22 , that is to say, the sun gear 221 and the motor shaft 214 are integrally formed. A plurality of planetary gears 222 are positioned at the radially outer side of the sun gear 221 and are evenly distributed along the circumferential direction. The rotation of the central axis and the revolution around the sun gear 221. The planetary gear carrier 223 is located radially outside the sun gear 221 , and a plurality of planetary gears 222 are mounted on the planetary gear carrier 223 , and the planetary gear carrier 223 is fixed to the output shaft 24 . As the planetary gear 222 revolves, it can drive the planetary gear carrier 223 to rotate and then drive the output shaft 24 to rotate. The ring gear 224 is located on the radially outer side of the multiple planetary gears 222 and is fixed to the steering knuckle 1. A track for the multiple planetary gears 222 to revolve is formed between the ring gear 224 and the sun gear 221. The ring gear 224 and the multiple planetary gears 222 tooth meshing.

In this embodiment, as shown in FIG. 2 , FIG. 3 and FIG. 6 , the housing assembly 23 includes a first housing 231 and a second housing 232 . The second housing 232 can be fixed to the installation part 11 of the steering knuckle 1 through interference fit, and the corresponding structure of the second housing 232 and the installation part 11 of the steering knuckle 1 surrounds and forms the first installation space S1, and the planetary gear reduction mechanism 22 is installed in the first installation space S1. The first housing 231 is detachably mounted on the steering knuckle 1 by using the first mounting hole 11h1. In addition, a second installation space S2 is formed inside the first housing 231 , and other components of the motor assembly 21 are installed in the second installation space S2 except the motor shaft 214 . In addition, the motor shaft 214 extends from the second installation space S2 into the first installation space S1 , and the output shaft 24 extends from the first installation space S1 through the through hole 11 h of the steering knuckle 1 to the other axial side of the steering knuckle 1 . In this embodiment, as shown in FIG. 2 , FIG. 3 and FIG. 6 , the output shaft 24 is arranged coaxially with the motor shaft 214 , so that the entire driving mechanism 2 has a coaxial structural layout.

In this embodiment, as shown in FIGS. 2 and 3 , the wheel bearing 3 includes an inner ring 31 , an outer ring 32 and rolling elements 33 . The outer ring 32 is detachably mounted to the mounting portion 11 using the second mounting hole 11h2 of the knuckle 1 . The inner ring 31 is coupled with the output shaft 24 through spline transmission. When the inner ring 31 and the outer ring 32 rotate relative to each other, the rolling elements 33 can roll in the raceways of the outer ring 32 and the inner ring 31 . In this embodiment, the wheel bearing 3 may be a double row ball bearing.

In this embodiment, as shown in FIGS. 1 to 3 , the brake system 4 is a floating caliper disc brake system. The braking system includes a brake caliper mechanism (including a brake caliper, a brake cylinder, etc.) and a brake disc 41 . Using any set of third mounting holes 11h3 of the steering knuckle 1 , the brake caliper mechanism of the braking system 4 is detachably mounted on the mounting portion 11 . The brake disc 41 of the brake system 4 is fixed to the inner ring 31 so as to be relatively fixed to the output shaft 24 , and the brake disc 41 is arranged coaxially with the output shaft 24 . In this way, through the movement of the piston in the brake cylinder, the floating brake caliper can be driven to clamp the brake disc 41, thereby generating a frictional moment that prevents the rotation of the wheel WH, thereby achieving braking.

In this embodiment, in order to ensure the normal operation of the motor shaft 214 and the output shaft 24, the in-wheel motor drive system DR includes two motor bearings B1 and one support bearing B2. Two motor bearings B1 are located between the first housing 231 and the motor shaft 214 . A support bearing B2 is located between the mounting portion 11 of the steering knuckle 1 and the output shaft 24 .

The present application also provides a motor vehicle including the above-mentioned in-wheel motor drive system DR, and the motor vehicle may especially be an electric vehicle with more than two wheels. In an optional example of a motor vehicle according to the present application, the motor vehicle comprises four wheels WH to which the in-wheel motor drive system DR is mounted. As shown in Figures 1 and 2, the wheel bearing 3 of the in-wheel motor drive system DR, the brake system 4 and the installation part 11 of the steering knuckle 1 are located inside the wheel WH, and a part of the bending part 12 of the steering knuckle 1 extends to the wheel. Exterior of WH. In addition, the drive mechanism 2 may be located outside the wheel WH. In order to transmit torque from the drive mechanism 2 to the wheel WH, the inner ring 31 is fixed to the hub HU of the wheel WH. In this way, the torque transmission path from the motor of the drive mechanism 2 is as follows: rotor 212→rotor bracket 213→motor shaft 214→sun gear 221→planetary gear 222→planetary carrier 223→output shaft 24→inner ring 31→wheel WH.

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

i. By adopting the above structure, on the one hand, with the steering knuckle 1 as a reference, the braking system 4 and the wheel bearing 3 are located on the side opposite to the side where the driving mechanism 2 is located, and the braking system 4 and the wheel bearing 3 are detachably installed on the steering knuckle 1. The inner ring 31 of the wheel bearing 3 is connected to the output shaft 24 of the drive system through spline transmission. The above structure is beneficial to the steering knuckle 1 and other components of the in-wheel motor drive system DR of the present application and different brake systems 4 and wheels. The bearing 3 is fitted and disassembled, thereby improving the versatility of the in-wheel motor drive system DR of the present application. Moreover, since the planetary gear reduction mechanism 22 uses the steering knuckle 1 as a part of its housing, the housing originally used as the planetary gear reduction mechanism 22 is omitted or simplified, thereby reducing the axial length of the in-wheel motor drive system DR of the present application. Small.

On the other hand, it is possible to transmit torque from the in-wheel motor drive system DR to the output shaft 24 to drive the wheel hub HU, and ultimately drive the wheels WH. In this way, the motor directly drives the wheel WH of the motor vehicle without the conventional transmission and drive shaft outside the wheel WH, thus shortening the torque transmission path compared with the drive system of the prior art motor vehicle, so that the efficiency of the drive system is improved And the energy loss in the transmission process is reduced. Moreover, the drive mechanism 2, the wheel bearing 3 and the brake disc 41 are coaxially arranged, which can save the occupied space, and the in-wheel motor drive system DR is integrated with the wheel WH, which is convenient for the structural layout of the motor vehicle and reduces the load on the machine. The impact of space interference when the train is in bumps and turns.

ii. It can be understood that seals can be provided between the first housing 231 and the motor shaft 214, between the steering knuckle 1 and the output shaft 24, and between the inner ring 31 and the outer ring 32 of the wheel bearing 3 as required components.

iii. In the above embodiments, the sun gear 221 of the planetary gear reduction mechanism 22 is integrated with the motor shaft 214, which is beneficial to simplify the structure and reduce the cost. In other optional solutions, the sun gear 221 and the motor shaft 214 can be manufactured separately, and then the transmission connection is realized through interference, form fit, key connection or spline engagement.

Claims (10)

1. An in-wheel motor drive system, characterized in that the in-wheel motor drive system (DR) comprises:

a knuckle (1), the knuckle (1) comprising a mounting portion (11);

the driving mechanism (2) is detachably mounted on the mounting part (11), and comprises a motor assembly (21), a planetary gear speed reducing mechanism (22), a shell assembly (23) and an output shaft (24), wherein the motor assembly (21) and the output shaft (24) are always in transmission connection through the planetary gear speed reducing mechanism (22), the output shaft (24) penetrates through the mounting part (11) along the axial direction (A) and can rotate relative to the mounting part (11), and the planetary gear speed reducing mechanism (22) is positioned in a first mounting space (S1) surrounded by the shell assembly (23) and the mounting part (11);

the wheel bearing (3), the wheel bearing (3) comprises an inner ring (31) and an outer ring (32), the outer ring (32) is detachably arranged on the mounting part (11), and the inner ring (31) is in spline transmission connection with the output shaft (24); and

a brake system (4), the brake system (4) comprising a brake disc (41) and a brake caliper mechanism, the brake disc (41) and the output shaft (24) being relatively fixed, the brake caliper mechanism being detachably mounted to the mounting portion (11),

in the axial direction (A), the drive mechanism (2) is located on one side of the mounting (11), and the wheel bearing (3) and the brake system (4) are located on the other side of the mounting (11).

2. The in-wheel motor drive system according to claim 1, wherein the drive mechanism (2) includes a stator (211), a rotor (212), and a motor shaft (214), the planetary gear reduction mechanism includes a sun gear (221), a planetary gear (222), a planetary carrier (223), and a ring gear (224),

the rotor (212) can rotate relative to the stator (211), the rotor (212) is in transmission connection with the sun gear (221) via the motor shaft (214), the output shaft (24) is in transmission connection with the planet wheel carrier (223), the gear ring (224) is fixed with the mounting part (11),

the motor shaft (214) is arranged coaxially with the output shaft (24).

3. In-wheel motor drive system according to claim 1, characterized in that the brake disc (41) is fixed with the inner ring (31), the brake disc (41) being arranged coaxially with the output shaft (24).

4. A wheel hub motor drive system according to any one of claims 1-3, characterized in that a second installation space (S2) is formed inside the housing assembly (23), the motor assembly (21) being installed in the second installation space (S2).

5. A wheel hub motor drive system according to any one of claims 1 to 3, wherein the mounting portion (11) is formed with a plurality of sets of mounting holes (11 h 3) penetrating along the axial direction (a), and the caliper mechanism is fixedly connected to the mounting portion (11) via a connection member penetrating any one of the plurality of sets of mounting holes (11 h 3).

6. The in-wheel motor drive system according to claim 2, characterized in that the in-wheel motor drive system (DR) further comprises a motor bearing (B1) and a support bearing (B2), the motor bearing (B1) being located between the motor shaft (214) and the housing assembly (23), the support bearing (B2) being located between the output shaft (24) and the mounting portion (11).

7. A wheel hub motor drive system according to any one of claims 1-3, characterized in that the steering knuckle (1) further comprises a bending part (12), a first pivot part (13) and a second pivot part (14), the bending part (12) protruding from the mounting part (11), the first pivot part (13) being fixed with the bending part (12), the second pivot part (14) being fixed with the mounting part (11).

8. A motor vehicle, characterized in that it comprises an in-wheel motor drive system (DR) according to any one of claims 1 to 7.

9. Motor vehicle according to claim 8, characterized in that it comprises a Wheel (WH), the wheel bearing (3), the brake system (4) and the mounting (11) of the knuckle (1) being located inside the Wheel (WH), a portion of the bend (12) of the knuckle (1) extending outside the Wheel (WH).

10. Motor vehicle according to claim 8 or 9, characterized in that the inner ring (31) is fixed to the hub of the Wheel (WH).

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