CN106143120B - The wheel motor drive device of electric vehicle and electric vehicle method of work - Google Patents

Abstract

The invention provides a wheel hub motor driving device of an electric vehicle and a working method of the electric vehicle, which includes a motor, a left planetary gear system, a right planetary gear system, a brake mechanism and a controller. There are left clutches and right clutches respectively at the two ends of the two ends, and the left clutches and right clutches are connected with the controller; the left planetary gear train and the right planetary gear train both include a sun gear, at least three rotationally positioned planetary gears and fixed on the hub The ring gear on the inner wall, all the planetary gears are evenly distributed around the sun gear and meshed with the sun gear, all the planetary gears are located in the ring gear and meshed with the ring gear; the two sun gears are symmetrically installed on the motor The left and right ends of the shaft rotate relative to the motor shaft, and the left clutch and the right clutch are in a state of engagement or disconnection under the control of the controller. The invention greatly improves the stability when the wheels of the electric vehicle rotate and the flexibility when the vehicle turns and controls.

Description

Wheel hub motor driving device of electric vehicle and working method of electric vehicle

technical field

The invention relates to the technical field of driving electric vehicles, in particular to a wheel hub motor driving device of the electric vehicle and a working method of the electric vehicle.

Background technique

In recent years, the development of electric vehicles has made great progress, and the application of in-wheel motor drive devices as the core components of electric vehicles is also increasing. Among the currently commonly used hub motor drive devices for electric vehicles, some are non-circumferentially symmetrical in cross section, which affects the stability of the vehicle wheel rotation; flexibility; some structures are too complex, which affects the convenience and economy of automobile wheel tire disassembly and maintenance; the economics of electric vehicles.

Chinese patent 201610100566.0 discloses a new energy vehicle hub motor powertrain drive system, including an axial and disc motor integrated machine, consisting of a stator and a rotor, with a built-in stator and an external rotor, and tires are directly mounted on the external rotor; brakes are also included Calipers, shock absorbers and connecting brackets, floating brake discs, the brake calipers are installed on the axial inner surface of the stator close to the edge of the car, the opening of the caliper matches the floating brake discs outward; the floating brake discs use multiple bolts It is fixed on the end surface of the outer rotor axially facing the car; the shock absorbing and connecting bracket is divided into upper and lower parts, which are installed on the axial inner wall of the stator; the central shaft of the hub motor is fastened by a thrust roller bearing, which consists of an axial and a disc type Driven by an electric motor. The new energy vehicle hub motor powertrain integrates the hub, outer rotor hub motor, brake calipers and brake pads, shock absorption and connecting rod bracket into one system, and uses the drive mode of the motor to directly drive the hub, which affects the power and economy.

Therefore, there is a need for an electric vehicle wheel hub motor driving device with good driving performance, stable rotation and flexible handling.

Contents of the invention

In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a hub motor drive device for an electric vehicle and a working method for an electric vehicle, which are used to solve the problem of the poor driving performance of an electric vehicle driven by a hub motor in the prior art. , The problem of poor stability.

In order to achieve the above object and other related objects, the present invention provides an in-wheel motor drive device for an electric vehicle, which includes an electric motor, a left planetary gear train, a right planetary gear train, a braking mechanism, and a controller fixed in the motor and controlling the action of the motor , the left planetary gear train and the right planetary gear train are symmetrically distributed on the left and right sides of the motor; wherein, the motor includes a motor shaft connected to the hub for rotation, the left end of the motor shaft is provided with a left clutch, the right end of the motor shaft is provided with a right clutch, and the left Both the clutch and the right clutch are connected with the controller; the left planetary gear train and the right planetary gear train both include a sun gear, at least three rotationally positioned planetary gears and an inner ring gear fixed on the inner wall of the hub, and all planetary gears surround the sun gear Evenly distributed in the circumferential direction and meshed with the sun gear, all the planetary gears are located in the ring gear and meshed with the ring gear; the two sun gears are symmetrically installed on the left and right ends of the motor shaft and connected to the motor shaft in rotation, the left The clutch is in the combined or disconnected state with the sun gear in the left planetary gear system under the control of the controller, and the right clutch is in the combined or disconnected state with the sun gear in the right planetary gear system under the control of the controller.

Preferably, the motor also includes a motor rotor, a motor stator, a left end cover, a right end cover and a housing, and the motor rotor and the motor stator are all placed in a cavity surrounded by the left end cover, the right end cover and the housing, and the motor The shaft is fixedly connected with the motor rotor, the left and right ends of the motor shaft pass through the left end cover and the right end cover respectively and are connected in rotation with the left end cover and the right end cover, and the controller is fixed on the left end cover or the right end cover.

Preferably, the motor stator is a hollow web structure.

Preferably, the planetary gears are rotatably mounted on the planetary gear shafts, and both ends of all the planetary gear shafts in the left planetary gear train are respectively fixed on the left planetary gear carrier and the left end surface of the housing, and the right planetary gears One end of all planetary gear shafts in the system is fixed on the right end face of the housing.

Preferably, the brake mechanism includes a brake disc and a brake caliper used in cooperation with each other, the brake disc is fixed on the hub, and the brake caliper is fixed on the left planetary wheel carrier.

Preferably, a shock absorber joint, a steering gear joint and a swing arm joint are also fixed on the left planetary gear frame.

Preferably, the addendum diameter of the ring gear in the left planetary gear train is larger than the addendum diameter of the ring gear in the right planetary gear train.

The present invention also provides a working method for an electric vehicle. The electric vehicle adopts the hub motor driving device of the electric vehicle as described above, and specifically includes the following working modes:

In the neutral starting mode, the electric vehicle starts, the motor rotates forward, and the controller controls the left clutch and the right clutch to be disconnected from the left planetary gear train and the right planetary gear train respectively;

In the low-speed driving mode, the controller controls the right clutch and the right planetary gear train to be in a disconnected state, the left clutch and the left planetary gear train to be in a combined state, the left planetary gear train works, and the motor rotates forward;

In the medium-high speed driving mode, the controller controls the left clutch and the left planetary gear train to be in a disconnected state, the right clutch and the right planetary gear train to be in a combined state, the right planetary gear train works, and the motor rotates forward;

In coasting brake power generation mode, the controller controls the left clutch and the left planetary gear train to be in a disconnected state, the right clutch and the right planetary gear train to be in a combined state, and the motor is reversely dragged for power generation braking;

In the reverse driving mode, the controller controls the right clutch and the right planetary gear train to be in a disconnected state, the left clutch and the left planetary gear train to be in a combined state, and the electric motor reverses.

As mentioned above, the hub motor driving device of the electric vehicle and the working method of the electric vehicle of the present invention have the following beneficial effects: the hub motor driving device is divided into several large modules: electric motor, left planetary gear train, right planetary gear train and controller , the modules are distributed in a quasi-symmetrical form, so that the cross-section of the in-wheel motor drive device has both the structural characteristics of circumferential symmetry (circumferential symmetry refers to the uniform distribution of modules around the motor shaft around the motor shaft) and the approximate The structural characteristics of left and right symmetry; the quasi-symmetrical structure distribution greatly improves the stability of the electric vehicle wheel rotation and the flexibility of the vehicle steering control; the simple modular structure and the reasonable deployment of the double planetary gear system not only improve the vehicle The safety during operation and the convenience during use enable the motor to work in a high-efficiency speed range according to the driving conditions of the electric vehicle, thereby improving both the power of the electric vehicle and the economy of the electric vehicle.

Description of drawings

FIG. 1 is a schematic cross-sectional view of an in-wheel motor driving device for an electric vehicle according to the present invention.

Component designation description

1 tire

2 hubs

3 left planetary gear train

31 Left inner ring gear

32 Left planetary gear

33 Left planet shaft

34 left sun gear

35 Left planet carrier

4 Right planetary gear train

41 Right inner ring gear

42 Right planetary gear

43 Right planetary shaft

44 Right sun gear

51 right clutch

52 left clutch

6 motors

61 Motor shaft

62 Right end cap

63 Left end cap

64 Motor rotor

65 motor stator

66 housing

7 brake disc

8 brake calipers

9 Shock absorber connector

10 controllers

11 Steering Gear Connector

12 Swing arm joint

101 hub bearing

Detailed ways

The implementation of the present invention will be illustrated by specific specific examples below, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

See Figure 1. It should be noted that the structures, proportions, sizes, etc. shown in the drawings attached to this specification are only used to match the content disclosed in the specification, for those who are familiar with this technology to understand and read, and are not used to limit the implementation of the present invention. Limiting conditions, so there is no technical substantive meaning, any modification of structure, change of proportional relationship or adjustment of size, without affecting the effect and purpose of the present invention, should still fall within the scope of the present invention. within the scope covered by the disclosed technical content. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit this specification. The practicable scope of the invention and the change or adjustment of its relative relationship shall also be regarded as the practicable scope of the present invention without any substantial change in the technical content.

As shown in Figure 1, the present invention provides a kind of in-wheel motor driving device of electric vehicle, and it comprises wheel hub 2, is placed in the tire 1 outside wheel hub 2, is placed in the following structure in wheel hub 2: motor 6, left planetary gear train 3 , the right planetary gear train 4, the braking mechanism and the controller 10 fixed in the motor 6 and controlling the action of the motor 6, the left planetary gear train 3 and the right planetary gear train 4 are symmetrically distributed on the left and right sides of the motor 6; wherein, the motor 6 Including the motor shaft 61 that is connected to the wheel hub 2 in rotation, the motor shaft 61 is connected to the wheel hub 2 through the wheel hub bearing 101, the left end of the motor shaft 61 is provided with a left clutch 52, and the right end of the motor shaft 61 is provided with a right clutch 51, a left clutch 52, Right clutch 51 is all linked to each other with controller 10; Left planetary gear train 3 and right planetary gear train 4 all comprise sun gear (left sun gear 34, right sun gear 44 among Fig. 1), at least three planetary gears ( In Fig. 1, the left planetary gear 32, the right planetary gear 42) and the inner ring gear fixed on the inner wall of the hub (the left inner ring gear 31, the right inner ring gear 41 in Fig. 1), all the planetary gears are evenly distributed around the circumference of the sun gear And all are meshed with the sun gear, all planetary gears are located in the ring gear and meshed with the ring gear; two sun gears (left sun gear 34, right sun gear 44 in Figure 1) are symmetrically installed on the motor shaft 61 The left and right ends are rotationally connected with the motor shaft 61, the left clutch 52 is in a combined or disconnected state with the sun gear (i.e. the left sun gear 34) in the left planetary gear train 3 under the control of the controller 10, and the right clutch 51 is in the control state. Under the control of the device 10, it is in a combined or disconnected state with the sun gear (ie the right sun gear 44) in the right planetary gear train 4.

The wheel hub motor driving device of the electric vehicle of the present invention is divided into several big modules: motor 6, left planetary gear train 3, right planetary gear train 4 and controller 10, each module is distributed with quasi-symmetrical form, makes the horizontal axis of the hub motor driving device The cross-section has both 360°circumferential symmetry and approximately left-right symmetry. Circumferential symmetry means that each module is evenly distributed around the motor shaft around the motor shaft 61. Left-right symmetry means that the left planetary gear train and The right planetary gear train is symmetrical to the left and right of the motor; the quasi-symmetrical structure distribution greatly improves the stability of the electric vehicle's wheel rotation and the flexibility of the vehicle's steering control; the simple modular structure and the reasonable deployment of the double planetary gear train, both It improves the safety of the car during operation and the convenience of use, and enables the electric motor to work in a high-efficiency speed range according to the driving conditions of the electric car, thereby improving both the power of the electric car and the performance of the electric car. economy.

Above-mentioned electric motor 6 specifically also comprises motor rotor 64, motor stator 65 and left end cover 63, right end cover 62 and casing 66, and motor rotor 64 and motor stator 65 all place and are surrounded by left end cover 63, right end cover 62 and casing 66. In the cavity, the motor shaft 61 is fixedly connected with the motor rotor 64, the left and right ends of the motor shaft 61 pass through the left end cover 63 and the right end cover 62 respectively, and are connected to the left end cover and the right end cover through bearings in rotation, the controller 10 It is fixed on the left end cover 63 or the right end cover 62. The motor 6 in the present invention is located at the center of the entire wheel hub motor drive device; the motor shaft 61 is a long axis, which is an axial positioning support element for each module unit of the entire electric vehicle hub motor drive device, and can be designed as a hollow structure so as to reduce weight; Body 66 is the core skeleton element of the entire electric vehicle hub motor drive device, responsible for building and maintaining the spatial relationship of each module unit of the entire electric vehicle hub motor drive device; the motor stator 65 can be designed as a hollow web structure, which can reduce weight and A space can be made for arranging the controller 10 .

The above-mentioned controller 10 is an integrated body of electronic software and electronic and electrical hardware that coordinates and directs the in-wheel motor driving device of the entire electric vehicle to work normally. The controller 10 can be designed as an integral structure or as an array structure. The integral controller can be fixedly arranged on the left end cover 63 (the controller 10 is fixed on the left end cover 63 in FIG. 1 ) or the side of the right end cover 62 as required; side of the cover. The controller 10 can send instructions such as start, acceleration, constant speed, deceleration, stop, reverse, and generate electricity to the motor as required; Can not send combination instruction simultaneously to left clutch and right clutch); Controller 10 is also responsible for the information exchange work between other external controllers simultaneously.

The left planetary gear system 3 is located on the left side of the motor. As shown in FIG. . The motor shaft 61 passes through the center of the left sun gear 34, and the left sun gear 34 is rotationally connected with the motor shaft 61 through a bearing. All the left planetary gears 32 are evenly distributed around the circumference of the left sun gear 34 . One end of each left planetary wheel shaft 33 is fixedly connected to the left end surface of the housing 66, and the other end of each left planetary wheel shaft 33 is fixedly connected to the above-mentioned left planetary wheel carrier 35, that is, the left planetary wheel carrier 35 is placed on the left end of the left planetary wheel 32. The gear teeth of the left sun gear 34 mesh with the gear teeth of the left planetary gear 32 , and the gear teeth of the left planetary gear 32 mesh with the gear teeth of the left inner ring gear 31 . When the motor 6 is energized and the left clutch 52 is in the engaged state and the right clutch 51 is in the disengaged state, the motor rotor 64 drives the motor shaft 61 to rotate, and the motor shaft 61 can drive the left sun gear 34 to rotate. Since the left planetary gear shaft 33 in the left planetary gear train 3 is fixed, when the left sun gear 34 rotates, it can drive the left planetary gear 32 to rotate, and the left planetary gear 32 then drives the left inner ring gear 31 to rotate, finally realizing The purpose of driving the wheels and tires to rotate.

The right planetary gear system 4 is located on the right side of the motor, as shown in Figure 1, the right planetary gear system 4 is mainly composed of a right sun gear 44, at least three right planetary gears 42, a right inner ring gear 41, a right planetary gear shaft 43, and a right clutch 51 . The motor shaft 61 passes through the center of the right sun gear 44, and the right sun gear 44 is rotationally connected with the motor shaft 61 through a bearing. All the right planetary gears 42 are evenly distributed around the circumference of the right sun gear 44 . One end of each right planetary wheel shaft 43 is fixedly connected with the right end surface of the above-mentioned housing 66, and the other end of each right planetary wheel shaft 43 is suspended, or fixed on the right planetary wheel carrier, that is, the right planetary wheel carrier can be set according to selection. The gear teeth of the right sun gear 44 mesh with the gear teeth of the right planetary gear 42 , and the gear teeth of the right planetary gear 42 mesh with the gear teeth of the right inner ring gear 41 . When the motor 6 is energized and the right clutch 51 is in the engaged state and the left clutch 52 is in the disengaged state, the motor rotor 64 drives the motor shaft 61 to rotate, and the motor shaft 61 can drive the right sun gear 44 to rotate. Since the right planetary gear shaft 43 in the right planetary gear train 4 is fixed, when the right sun gear 44 rotates, it can drive the right planetary gear 42 to rotate, and the right planetary gear 42 then drives the right inner ring gear 41 to rotate, finally realizing The purpose of driving the wheels and tires to rotate.

The brake mechanism above includes a brake disc 7 and a brake caliper 8 that are used in conjunction with each other. The brake disc 7 is fixed on the hub 2 , and the brake caliper 8 is fixed on the left planetary wheel carrier 35 . In this way, the brake caliper 8 is fixed, and when the brake caliper 8 receives the brake command, it can apply a braking force to the brake disc 7, thereby causing the wheel hub and tire to brake to decelerate or brake to stop. The position of brake disc 7 and brake caliper 8 also can be arranged on the right side of right planetary gear train as required, also can be arranged between left planetary gear train and right planetary gear train as required. The shock absorber joint 9, the steering gear joint 11 and the swing arm joint 12 are also fixedly arranged on the left planetary wheel carrier 35.

In this embodiment, the gear ratio of the left planetary gear 3 is greater than that of the right planetary gear 4, that is, the left planetary gear 3 is a low-speed speed reducer, and the right planetary gear 4 is a medium-high speed gear. The addendum diameter of the ring gear in the left planetary gear train (ie the left ring gear 31) is greater than the addendum diameter of the ring gear in the right planetary gear train (ie the right ring gear 41) (see Figure 1 ), thus when the wheel tire needs to be maintained and repaired, the wheel tire can be easily and quickly disassembled from the right side of the electric vehicle hub motor drive device and reinstalled.

Using the above-mentioned wheel hub motor driving device of the present invention, the electric vehicle has the following five working modes: neutral start mode, low-speed driving mode, medium-high speed driving mode, coasting braking power generation mode and reverse driving mode.

Neutral start mode, when the electric vehicle starts, the controller 10 instructs the left clutch 52 and the right clutch 51 to be in the disconnected state, and the left planetary gear system 3 (low-speed reducer) and the right planetary gear system 4 (medium-high speed reducer) are both When not running, the electric motor 6 is energized and rotates forward to start the electric vehicle, and the drive device of the hub motor of the electric vehicle works in a neutral starting mode. At this time, the electric vehicle starts without load, and the whole starting process is safe, reliable, fast and economical.

Low-speed driving mode, when the electric vehicle starts and runs at a low speed, the controller 10 instructs the right clutch 51 and the right planetary gear train 4 to be in a disconnected state, the left clutch 52 and the left planetary gear train 3 are in a combined state, and the left planetary gear train 3 ( The low-speed reducer) works, the motor 6 is energized and rotates forward, and the electric vehicle wheel hub motor driving device works in the low-speed driving mode. At this time, the electric motor 6 can work in the middle and low speed range with high efficiency, and the rotational torque obtained by the hub tire is relatively large, so the power and economy of the electric vehicle are relatively good.

In the medium-to-high-speed driving mode, when the electric vehicle is traveling at a medium-to-high speed, the controller 10 instructs the left clutch 52 to be in a disengaged state with the left planetary gear train 3, the right clutch 51 to be in a combined state with the right planetary gear train 4, and the right planetary gear train 4 ( medium-high speed reducer) works, the motor 6 is energized and rotates forward, and the electric vehicle wheel hub motor driving device works in the medium-high speed driving mode. At this time, the motor can work in the high-efficiency medium-to-high speed range, and the rotational torque obtained by the wheel hub and tire is moderate, and the overall performance of the electric vehicle is better.

In coasting braking power generation mode, when the electric vehicle is coasting and braking, the controller 10 instructs the left clutch 52 to be disconnected from the left planetary gear train 3, the right clutch 51 to be in a combined state with the right planetary gear train 4, and the right planetary gear train 4 to be in a combined state. (medium-high-speed reducer) works, the motor 6 is anti-drag power generation braking, and the electric vehicle wheel hub motor driving device works in the coasting braking power generation mode. At this time, part of the coasting braking energy of the electric vehicle is converted into electric energy by the electric motor and fed back to the battery, so the economy of the electric vehicle is better.

In the reverse driving mode, when the electric vehicle reverses, the controller 10 instructs the right clutch 51 and the right planetary gear 4 to be in a disconnected state, the left clutch 52 and the left planetary gear 3 are in a combined state, and the left planetary gear 3 (low speed reducer ) work, the motor 6 is energized and reversed, and the electric vehicle hub motor driving device works in the reverse driving mode. At this time, the electric motor 6 can work in the middle and low speed range with high efficiency, and the rotational torque obtained by the hub tire is relatively large, so the power and economy of the electric vehicle are relatively good.

In addition, when the electric vehicle is in any of the above working modes, the controller 10 can control the brake caliper 8 to apply a braking force to the brake disc 7 at any time according to the needs, so as to cause the wheel hub tires to brake to decelerate or brake to stop. At this time, the controller 10 can control the driving device of the electric vehicle hub motor to quickly switch to the coasting braking power generation mode, which not only ensures the handling and safety of the electric vehicle, but also improves the economy of the electric vehicle.

In summary, the hub motor driving device and the electric vehicle working method of the electric vehicle of the present invention divide the hub motor driving device into several large modules: the electric motor, the left planetary gear train, the right planetary gear train and the controller, and each module is divided into The quasi-symmetric distribution makes the cross-section of the in-wheel motor drive device not only have the structural characteristics of circumferential symmetry (circumferential symmetry means that each module is evenly distributed around the motor shaft around the motor shaft) but also have approximately left-right symmetric structural features ; The quasi-symmetric structure distribution greatly improves the stability of the electric vehicle wheel rotation and the flexibility of the vehicle steering control; the simple modular structure and the reasonable deployment of the double planetary gear system not only improve the safety of the vehicle during operation And the convenience of use enables the motor to work in a high-efficiency speed range according to the driving conditions of the electric vehicle, thereby improving the power of the electric vehicle and improving the economy of the electric vehicle. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (8)

1. An in-wheel motor driving device for an electric vehicle, comprising an electric motor (6), a left planetary gear train (3), a right planetary gear train (4), a braking mechanism, and a motor (6) fixed inside and controlled by the motor (6) The action controller (10) is characterized in that the left planetary gear train (3) and the right planetary gear train (4) are symmetrically distributed on the left and right sides of the motor (6); wherein, The motor (6) comprises a motor shaft (61) connected to the wheel hub (2) in rotation, the left end of the motor shaft (61) is provided with a left clutch (52), the right end of the motor shaft (61) is provided with a right clutch (51), the left Clutch (52), right clutch (51) are all linked to each other with controller (10); The left planetary gear system (3) and the right planetary gear system (4) both include a sun gear, at least three rotationally positioned planetary gears and an inner ring gear fixed on the inner wall of the hub, and all planetary gears are evenly distributed around the sun gear And all mesh with the sun gear, all planetary gears are located in the ring gear and mesh with the ring gear; The two sun gears are symmetrically installed on the left and right ends of the motor shaft (61) and connected in rotation with the motor shaft (61). The left clutch (52) is connected with the left planetary gear train (3) under the control of the controller (10). The sun gear is in a combined or disconnected state, and the right clutch (51) is in a combined or disconnected state with the sun gear in the right planetary gear train (4) under the control of the controller (10). 2. The in-wheel motor driving device of an electric vehicle according to claim 1, characterized in that: the motor (6) also includes a motor rotor (64), a motor stator (65), a left end cover (63), a right end cover ( 62) and the housing (66), the motor rotor (64) and the motor stator (65) are placed in the cavity surrounded by the left end cover (63), the right end cover (62) and the housing (66), the The motor shaft (61) is fixedly connected with the motor rotor (64), the left and right ends of the motor shaft (61) pass through the left end cover (63) and the right end cover (62) respectively, and the controller (10) is fixed on the left end cover ( 63) or the right end cap (62). 3. The in-wheel motor driving device of an electric vehicle according to claim 2, characterized in that: the motor stator (65) is a hollow web structure. 4. The in-wheel motor driving device of an electric vehicle according to claim 2, characterized in that: the planetary wheels are rotatably mounted on the planetary wheel shafts, and the two ends of all the planetary wheel shafts in the left planetary gear train (3) are respectively Fixed on the left end surface of the left planetary gear carrier (35) and the housing (66), one end of all planetary gear shafts in the right planetary gear train (4) is fixed on the right end surface of the housing (66) superior. 5. The in-wheel motor driving device of an electric vehicle according to claim 4, characterized in that: the brake mechanism includes a brake disc (7) and a brake caliper (8) used in conjunction with each other, and the brake disc (7) is fixed on the On the above-mentioned wheel hub (2), the brake caliper (8) is fixed on the left planetary wheel carrier (35). 6. The in-wheel motor driving device of an electric vehicle according to claim 4, characterized in that: the left planetary wheel carrier (35) is also fixed with a shock absorber joint (9), a steering gear joint (11) and Swing arm joint (12). 7. The in-wheel motor driving device of an electric vehicle according to claim 1, characterized in that: the tooth tip diameter of the inner ring gear in the left planetary gear train (3) is larger than that of the right planetary gear train (4) The tooth tip diameter of the ring gear. 8. A working method for an electric vehicle, characterized in that: the electric vehicle adopts the in-wheel motor driving device of the electric vehicle according to any one of claims 1 to 7, specifically including the following several working modes: In the neutral starting mode, the electric vehicle starts, the motor (6) rotates forward, and the controller (10) controls the left clutch (52), the right clutch (51) and the left planetary gear train (3), the right planetary gear train respectively (4) In disconnected state; In low-speed driving mode, the controller (10) controls the right clutch (51) and the right planetary gear train (4) to be disconnected, the left clutch (52) and the left planetary gear train (3) to be in a combined state, and the left planetary gear The system (3) works, and the motor (6) rotates forward; In medium-to-high speed driving mode, the controller (10) controls the left clutch (52) to be disconnected from the left planetary gear train (3), the right clutch (51) to be in a combined state to the right planetary gear train (4), and the right planetary gear train (4) to be in a combined state. The gear train (4) works, and the motor (6) rotates forward; In coasting braking power generation mode, the controller (10) controls the left clutch (52) to be disconnected from the left planetary gear train (3), the right clutch (51) to be in a combined state to the right planetary gear train (4), and the motor (6) Being anti-dragged and generating braking; In the reverse driving mode, the controller (10) controls the right clutch (51) to be disconnected from the right planetary gear train (4), the left clutch (52) to be in a combined state to the left planetary gear train (3), and the electric motor (6 ) inversion.