Electric drive power wheel system based on multi-stage damping design

Abstract

The application discloses a kind of electric drive power wheel systems based on multistage damping design, it is related to new energy carrying system technical field.The application is applied to electric automobile wheel drive field, including the wheel hub being installed on wheel, the central position of the wheel hub is rotatably connected with support shaft, the outer surface of the support shaft is fixedly installed with motor shell, the inside of the motor shell is installed with stator and planetary gear reduction assembly, and first damping structure is installed between planetary gear reduction assembly and wheel hub.The additional mass of in-wheel motor and steering servo motor is decoupled from unsprung mass by rubber element and in-wheel shock absorber, the newly added unsprung mass is converted into power vibration absorption advantage by reconstructing parallel-serial composite vibration topology, effectively solve the problem of vertical dynamics characteristic deterioration caused by the increase of unsprung mass due to the introduction of drive motor and steering motor, improve the wheel grounding performance and service life of parts.

Description

Technical Field

[0001] This invention relates to the field of new energy transportation system technology, specifically to an electric drive power wheel system based on multi-stage vibration reduction design. Background Technology

[0002] With the innovation of electrification and intelligent technology in new energy transportation systems, the integration and modularization of vehicle chassis has become an important development direction. Corner module technology integrates the drive, braking, suspension, and steering systems into a single assembly, significantly reducing mechanical transmission components and optimizing the overall vehicle space layout. Based on this technology, each wheel can achieve independent drive and steering, greatly improving vehicle maneuverability and handling agility. At the same time, the distributed drive architecture further enhances driving safety through multi-wheel redundancy design.

[0003] In the corner module, the hub motor, as the core drive component, is embedded inside the wheel hub, connected to the wheel via a flange, and drives its forward and reverse rotation. The steering knuckle is rigidly connected to the support shaft and connected to the vehicle body via the suspension control arm. The suspension damping system is installed between the upper control arm and the vehicle body to attenuate the vibration energy transmitted from the road surface to the vehicle body, ensuring vehicle ride comfort. However, the introduction of the hub motor and the steering motor located on the upper control arm of the suspension significantly increases the unsprung mass of the corner module, thereby deteriorating the vertical dynamic performance, specifically manifested as increased vehicle body vibration, fluctuating tire contact characteristics, and decreased ride comfort. To improve ride comfort, numerous studies have been conducted on mitigating the negative vertical impacts caused by the increased unsprung mass, and various solutions have been proposed, such as motor weight reduction, in-wheel suspension systems, and active and semi-active suspensions. Lightweighting the hub motor, suspension, and wheel hub is an effective way to reduce the mass of the electric wheel. However, in the current development of corner modules, structural designs addressing vibration damping are relatively few.

[0004] An existing patent (publication number: CN110154736B) discloses an electric wheel with in-wheel vibration damping function. This device adopts a composite vibration damping structure of annular hydraulic bushing and double swing arm suspension. However, the synergistic effect of large and small shock absorbers, swing arms and balance bars in the suspension relies on complex rotating pair connections, which leads to sluggish dynamic response of the system and affects the suppression efficiency of high-frequency vibration. In addition, the rotor housing and wheel rim transmit torque through the slot-pin structure of the central transmission disk. This mechanical coupling method is prone to gap wear under long-term impact loads, which causes a decrease in the magnetic gap stability of the motor and affects the accuracy of output torque. Therefore, this invention proposes an electric drive power wheel system based on multi-stage vibration damping design. Summary of the Invention

[0005] The purpose of this invention is to provide an electric drive wheel system based on multi-stage vibration reduction design. By using rubber elements and in-wheel dampers, the additional mass of the hub drive motor and steering motor is decoupled from the unsprung mass. By reconstructing the parallel-series composite vibration topology, the added unsprung mass is transformed into a dynamic vibration absorption advantage. This effectively solves the problem of deterioration of vertical dynamic characteristics caused by the increase in unsprung mass due to the introduction of drive motor and steering motor, and improves wheel ground contact performance and the service life of components.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an electric drive power wheel system based on multi-stage vibration reduction design, applied in the field of electric vehicle wheel drive, including a wheel hub mounted on the wheel, a support shaft rotatably connected to the center of the wheel hub, a motor housing fixedly mounted on the outer surface of the support shaft, a stator and a planetary gear reduction assembly installed inside the motor housing, and a first vibration reduction structure installed between the planetary gear reduction assembly and the wheel hub to attenuate high-frequency vibration of the motor;

[0007] A second vibration damping structure is installed between the motor housing and the support shaft to block the transmission of mid-frequency vibrations to the suspension system.

[0008] The suspension system includes a steering knuckle, with an upper control arm and a lower control arm hinged to the upper and lower ends of the steering knuckle, respectively. A support shaft is installed through the center hole of the steering knuckle, and a third damping structure is provided between the steering knuckle and the support shaft to absorb low-frequency vibrations caused by road surface undulations.

[0009] Furthermore, the hub and the support shaft are rotatably connected by a hub bearing.

[0010] Furthermore, the stator and the motor housing are both fixedly connected to the support shaft, and the motor rotor hub is rotatably connected inside the motor housing. The motor rotor hub and the support shaft are rotatably connected through a motor rotor hub bearing.

[0011] Furthermore, a rotor is mounted on the side wall of the motor rotor hub, and a planetary gear reduction assembly is also mounted on the motor rotor hub.

[0012] Furthermore, the planetary gear reduction assembly includes a sun gear, planet gears, a planet carrier, and a ring gear. The sun gear is connected to the motor rotor hub, the ring gear is fixedly connected to the motor housing via a flange, the planet gears are connected to the planet carrier via planetary pins, the planet carrier is connected to the hub via connecting bolts and a first damping structure, and the planet carrier is connected to the support shaft via a planet carrier bearing to form a rotating pair.

[0013] Furthermore, both the first and third vibration damping structures are configured as viscoelastic rubber elements;

[0014] The second vibration damping structure includes a rubber element and an in-wheel vibration damper installed between the motor housing and the support shaft.

[0015] The in-wheel shock absorber adopts a single-tube integrated passive damping structure with a mirror-symmetrical arrangement. The in-wheel shock absorber includes two sets of coaxially nested hydraulic damping units and a helical spring shock absorber. The hydraulic damping unit is a single-tube passive hydraulic damper, and the helical spring shock absorber housing is equipped with a displacement sensor at the end of the housing to detect the relative displacement between the support shaft and the motor housing in real time.

[0016] Furthermore, a steering servo motor is engaged on the steering knuckle, and the steering servo motor is rigidly connected to the upper control arm through a steering motor support.

[0017] Furthermore, the steering servo motor includes a worm gear reducer with a self-locking function, the output shaft of the steering servo motor meshes with the inner hole of the steering knuckle through an involute spline, and the axis of the output shaft of the steering servo motor passes through the rotation center of the steering knuckle and the center of the lower control arm ball joint.

[0018] Furthermore, the suspension system also includes an air spring and a magnetorheological damper. The air spring and the magnetorheological damper are arranged in parallel. The working cylinder of the magnetorheological damper is filled with magnetorheological fluid, and the damping force is changed stepwise through an electromagnetic coil.

[0019] Furthermore, the upper end of the steering knuckle is connected to the left end of the upper control arm, and the lower end is connected to the left end of the lower control arm, forming two revolute joints. The right ends of both the upper and lower control arms are connected to the vehicle frame through revolute joints.

[0020] The lower end of the magnetorheological damper forms a rotating pair with the lower cross arm, and the upper end is connected to the frame through a ball joint.

[0021] This invention has at least the following beneficial effects:

[0022] 1. This invention decouples the added mass of the hub drive motor and steering motor from the unsprung mass by using rubber elements and in-wheel dampers. By reconstructing the parallel-series composite vibration topology, the added unsprung mass is transformed into a dynamic vibration absorption advantage. Thus, starting from the frequency domain decoupling mechanism of the vibration energy transmission path, it effectively solves the problem of deterioration of vertical dynamic characteristics caused by the increase in unsprung mass due to the introduction of drive motors and steering motors, and improves the wheel ground contact performance and the service life of components.

[0023] 2. This invention filters vibrations in layers through a three-stage vibration reduction structure. The combination of rubber elements, in-wheel dampers and suspension dampers achieves full-frequency vibration suppression, which increases the controllable degrees of freedom in vertical dynamics.

[0024] 3. The steering mechanism of this invention is redesigned, eliminating the traditional mechanical steering linkage and using a distributed electronically controlled steering actuator to directly drive the wheels, avoiding the interference problem between the suspension guide mechanism and the steering transmission chain. The designed steering system has full-circumferential steering capability, enabling the vehicle to complete point steering and lateral movement functions with a very small turning radius.

[0025] 4. The corner module integrating in-wheel vibration damping and viscoelastic rubber elements of this invention also has the advantages of simple and compact overall structure, small size, and light weight.

[0026] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0027] Figure 1 This is a cross-sectional schematic diagram of the overall structure of the present invention;

[0028] Figure 2 The diagram shows the structure and model of the electric drive power wheel system of the present invention, wherein (a) is a structural diagram of the electric drive power wheel system and (b) is a structural diagram of a 1 / 4 model of the electric drive power wheel vehicle.

[0029] Figure 3 This is a schematic diagram comparing the acceleration amplitude of the spring mass of the corner module of this invention with that of a traditional corner module;

[0030] Figure 4 This is a schematic diagram comparing the tire dynamic load amplitude of the corner module of this invention with that of a traditional corner module.

[0031] Figure label:

[0032] 1. Wheel; 2. Motor housing; 3. Stator; 401. First damping structure; 402. Second damping structure; 403. Third damping structure; 5. Bolt; 6. Planetary carrier; 7. Planetary carrier bearing; 8. Wheel hub; 9. Wheel hub bearing; 10. Support shaft; 11. Motor rotor hub bearing; 12. Planetary pin; 13. Planetary gear reduction assembly; 14. Motor rotor hub; 15. Rotor; 16. Steering servo motor; 17. Steering motor support; 18. Upper control arm; 19. Magnetorheological damper; 20. Lower control arm; 21. Steering knuckle; 22. In-wheel damper. Detailed Implementation

[0033] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0034] Please see Figure 1 The present invention provides a technical solution: an electric drive power wheel system based on multi-stage vibration reduction design, applied to the field of electric vehicle wheel 1 drive, including a wheel hub 8 installed on the wheel 1, a support shaft 10 rotatably connected to the center of the wheel hub 8, a motor housing 2 fixedly installed on the outer surface of the support shaft 10, a stator 3 and a planetary gear reduction assembly installed inside the motor housing 2, and a first vibration reduction structure 401 installed between the planetary gear reduction assembly and the wheel hub 8 for attenuating high-frequency vibration of the motor;

[0035] A second vibration damping structure 402 is installed between the motor housing 2 and the support shaft 10 to block the transmission of mid-frequency vibration to the suspension system;

[0036] The suspension system includes a steering knuckle 21, with an upper control arm 18 and a lower control arm 20 hinged to the upper and lower ends of the steering knuckle 21, respectively. A support shaft 10 is installed through the center hole of the steering knuckle 21, and a third damping structure 403 is provided between the steering knuckle 21 and the support shaft 10 to absorb low-frequency vibrations caused by road surface undulations.

[0037] In this embodiment, the hub 8 and the support shaft 10 are rotatably connected by a hub bearing 9 to achieve radial support.

[0038] Regarding the technical solution of this embodiment, the stator 3 and the motor housing 2 are both fixedly connected to the support shaft 10. The motor housing 2 is rotatably connected to the motor rotor hub 14. The motor rotor hub 14 and the support shaft 10 are rotatably connected through the motor rotor hub 14 bearing 11. In actual driving, the planetary gear reduction assembly serves as the power output end.

[0039] In this embodiment, a rotor 15 is mounted on the side wall of the motor rotor hub 14, and a planetary gear reduction assembly is also mounted on the motor rotor hub 14.

[0040] Regarding the technical solution of this embodiment, the planetary gear reduction assembly includes a sun gear, planet gears, a planet carrier 6, and a gear ring. The sun gear is connected to the motor rotor hub 14 as the input end. The gear ring is fixedly connected to the motor housing 2 through a flange. The planet gears are connected to the planet carrier 6 through planetary pins 12. The planet carrier 6 is connected to the hub 8 through connecting bolts 5 and the first vibration damping structure 401. The planet carrier 6 is connected to the support shaft 10 through the planet carrier bearing 7 to form a rotating pair.

[0041] In this embodiment, both the first damping structure 401 and the third damping structure 403 are configured as viscoelastic rubber elements.

[0042] The second vibration damping structure 402 includes a rubber element and an in-wheel damper 22 disposed between the motor housing 2 and the support shaft 10. The rubber elements are all axisymmetric elements, and the stiffness characteristics of each rubber element are optimized based on the vibration mode characteristics of the motor-suspension coupling system.

[0043] The in-wheel shock absorber 22 adopts a single-tube integrated passive damping structure with a mirror-symmetrical arrangement. The in-wheel shock absorber 22 includes two sets of coaxially nested hydraulic damping units and a helical spring shock absorber. The hydraulic damping unit is a single-tube passive hydraulic damper, and the helical spring shock absorber housing is equipped with a displacement sensor at the end of the housing to detect the relative displacement between the support shaft 10 and the motor housing 2 in real time.

[0044] Regarding the technical solution of this embodiment, a steering servo motor 16 is meshed and installed on the steering knuckle 21. The steering servo motor 16 is rigidly connected to the upper control arm 18 through the steering motor support 17. The steering servo motor 16 includes a worm gear reducer with a self-locking function. Specifically, the steering servo motor 16 serves as a power source, and its housing is rigidly connected to the steering motor bracket through multiple sets of high-strength bolts 5. The steering motor bracket integrates a high-load-bearing angular contact thrust bearing. The output shaft of the steering servo motor 16 has an involute spline structure at its end, which forms a backlash-free torque transmission component with the spline groove corresponding to the inner hole of the steering knuckle 21. The steering motor bracket and the outer ring of the thrust bearing are fixed with a precision interference fit to construct a stable axial load transmission path. The rotation axis of the output shaft of the steering servo motor 16 precisely passes through the rotation center of the steering knuckle 21 and the ball joint center of the lower control arm in the spatial layout, forming multiple geometric collinear constraints, effectively controlling the motion deviation of the steering knuckle 21 when rotating around the axis.

[0045] Regarding the technical solution of this embodiment, the suspension system also includes an air spring and a magnetorheological damper 19. The air spring and the magnetorheological damper 19 are arranged in parallel to support active adjustment of stiffness and damping coefficient. The working cylinder of the magnetorheological damper 19 is filled with magnetorheological fluid, and the step change of damping force is realized through an electromagnetic coil.

[0046] Regarding the technical solution of this embodiment, the upper end of the steering knuckle 21 is connected to the left end of the upper control arm 18, and the lower end is connected to the left end of the lower control arm 20, forming two rotating joints. The right ends of both the upper and lower control arms 20 are connected to the vehicle frame through rotating joints.

[0047] The lower end of the magnetorheological damper 19 forms a rotating pair with the lower cross arm 20, and the upper end is connected to the frame through a ball joint.

[0048] The working principle of this invention is as follows: When road excitation is transmitted to the vehicle body through the tires and suspension system, the system's built-in three-stage damping structure works in concert:

[0049] The first vibration damping structure 401 uses high-rigidity rubber elements to connect the planetary carrier 6 and the hub 8 at the output end of the deceleration system, blocking the vertical jump of the wheel 1 from interfering with the dynamic balance of the motor rotor 15, ensuring the uniformity of the air gap magnetic field of the motor, and extending the service life of the motor.

[0050] The second vibration damping structure 402 includes a viscoelastic rubber element and an in-wheel damper 22. The rubber element connects the support shaft 10 to the motor stator 3, effectively absorbing the mid-frequency vibration energy caused by motor torque fluctuations using the internal friction damping of the viscoelastic material, thus blocking the transmission path of mid-frequency vibration to the suspension system. The passive in-wheel damper 22 adopts a pre-set nonlinear damping curve design, forming a fixed damping characteristic between the motor housing 2 and the support shaft 10 through mechanical structural parameter matching. This part dynamically decouples the motor mass from the unsprung mass and makes it act as a dynamic vibration absorber to reduce vibration.

[0051] The third damping structure 403 is set at the connection between the suspension double wishbone and the steering knuckle 21. It is equipped with a large-stroke rubber bushing, which absorbs low-frequency vibrations caused by road undulations by utilizing its large deformation capacity. At the same time, a magnetorheological damper 19 and an air spring are arranged in parallel on the lower control arm 20 of the suspension. The damping and elastic parameters are adjusted in real time through the coupling effect of electrorheological fluid and gas pressure. This part starts from the angle of the vibration of the wheel 1 to the vehicle body, reducing the vertical vibration of the vehicle body.

[0052] This integrated design not only improves the dynamic characteristics of the corner module system and the whole vehicle, but also significantly reduces the complexity of manufacturing and assembly through modular architecture, providing an innovative technical solution for the chassis system of new energy vehicles.

[0053] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0054] See Figure 2 In (a), during actual vehicle operation, the corner module vibration reduction system achieves vertical dynamic optimization through a three-level synergistic vibration reduction mechanism. Figure 2 Figure (b) shows the correspondence between the three-stage vibration damping units in the structural diagram and the 1 / 4 vehicle model, with I, II, and III representing the three-stage vibration damping units respectively.

[0055] When the road excitation is transmitted to the corner module through the tire, each damping unit responds collaboratively according to the vibration characteristics. The first damping structure 401 between the planetary carrier 6 on the wheel hub 8 motor and the wheel hub 8 takes effect first, quickly absorbing the high-frequency vibration energy transmitted by the tire. While ensuring power transmission efficiency, the first damping structure 401 significantly reduces the vibration amplitude of the motor rotor 15, effectively maintaining the stability of the internal magnetic field of the motor and avoiding torque fluctuations caused by high-frequency disturbances. The second damping structure 402 between the support shaft 10 and the motor stator 3 forms a composite damping system with the in-wheel damper 22. The second damping structure 402 suppresses mid-frequency vibration through viscoelasticity, while the passive in-wheel damper 22, based on a preset nonlinear damping curve, suppresses mid-frequency vibration through... The mechanical structure parameters are matched to form a fixed damping characteristic between the support shaft 10 and the hub 8 motor housing 2. The two work together to produce a mechanical decoupling effect, which not only blocks the transmission path of vibration to the suspension system, but also allows the hub 8 motor mass to act as a dynamic shock absorber through the resonance tuning of the mass-spring-damping system. When encountering severe impact, the upper and lower control arm 20 suspension system plays a leading role. The parallel combination of magnetorheological damper 19 and air spring adjusts the stiffness and damping parameters in real time. Together with the third damping structure 403 at the steering knuckle 21 connection, a multi-level buffer mechanism is formed. Ultimately, the synchronous optimization of sprung mass vibration, hub 8 motor impact and tire dynamic load is achieved, which comprehensively improves the vehicle's ride comfort and handling stability.

[0056] The vertical dynamics performance of the corner module was verified using a 1 / 4 scale vehicle model. In the figure, m1, m2, and m4 represent the wheel mass, sprung mass, and steering motor mass, respectively. 31 To support the mass of shaft 10 and steering knuckle 21, m 32 Let m be the mass of the hub motor stator 3, rotor 15, planetary gear reduction assembly 13, and its motor housing 2; m4 be the mass of the suspension arm and the steering servo motor 16 mounted on its upper cross arm 18; k1 and k2 be the spring stiffness of the tire and suspension, respectively; and k is used to represent the stiffness and damping of the viscoelastic rubber element. 41 k 42 k 43 and c 41 c 42 c 43 It means, c w ,c s The output damping of the in-wheel damper 22 and the electromagnetic semi-active damper are respectively obtained through the transfer function of the sprung mass acceleration and the tire dynamic load. Their amplitude-frequency characteristics H can be obtained. a and H t .

[0057] Depend on Figure 3It is evident that, under the same structural parameters, compared to existing conventional corner modules, except for a slightly larger amplitude of sprung mass acceleration in the low-frequency range of f < f0 = 0.108 Hz, the vibration amplitude of the corner module shows a significant reduction in other frequency ranges, with a maximum amplitude reduction of nearly 50.3 dB. This reduction is particularly noticeable in the human-sensitive region of 4-8 Hz. The tire dynamic load can be analyzed using the difference between tire displacement and road excitation, y1-y0, and the amplitude-frequency characteristics of y0. Figure 4 As can be seen, the tire dynamic load amplitude curve of the corner module changes relatively smoothly and is below that of the conventional corner module, showing a significant reduction. The above dynamic verification demonstrates that this invention, by decoupling the dynamic coupling of motor mass and unsprung mass and combining it with a graded vibration reduction strategy, successfully transforms the negative impact of the added unsprung mass in the drive and steering systems into a dynamic vibration absorption advantage.

[0058] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0059] For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances. When an element is referred to as being "assembled on," "mounted on," "fixed to," or "set on" another element, it may be directly on the other element or there may be an intermediate element present. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible embodiments.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0061] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. An electric drive power wheel system based on multi-stage vibration reduction design, applied in the field of electric vehicle wheel (1) drive, characterized in that, Includes a hub (8) mounted on a wheel (1), a support shaft (10) rotatably connected to the center of the hub (8), a motor housing (2) fixedly mounted on the outer surface of the support shaft (10), a stator (3) and a planetary gear reduction assembly (13) are installed inside the motor housing (2), and a first vibration damping structure (401) is installed between the planetary gear reduction assembly (13) and the hub (8) to attenuate high-frequency vibration of the motor; A second vibration damping structure (402) is installed between the motor housing (2) and the support shaft (10) to block the transmission of mid-frequency vibration to the suspension system; The suspension system includes a steering knuckle (21), with an upper control arm (18) and a lower control arm (20) hinged to the upper and lower ends of the steering knuckle (21) respectively. A support shaft (10) is provided through the center hole of the steering knuckle (21), and a third damping structure (403) is provided between the steering knuckle (21) and the support shaft (10) to absorb low-frequency vibrations caused by road surface undulations. Both the first damping structure (401) and the third damping structure (403) are configured as viscoelastic rubber elements; The second vibration damping structure (402) includes a rubber element and an in-wheel vibration damper (22) disposed between the motor housing (2) and the support shaft (10); The in-wheel damper (22) adopts a single-tube integrated passive damping structure with mirror symmetrical arrangement. The in-wheel damper (22) includes two sets of coaxially nested hydraulic damping units and helical spring dampers. The hydraulic damping unit is a single-tube passive hydraulic damper, and the helical spring damper housing is equipped with a displacement sensor at the end of the housing to detect the relative displacement between the support shaft (10) and the motor housing (2) in real time.

2. The electric drive wheel system based on multi-stage vibration reduction design according to claim 1, characterized in that: The hub (8) and the support shaft (10) are rotatably connected by a hub bearing (9).

3. The electric drive wheel system based on multi-stage vibration reduction design according to claim 2, characterized in that: The stator (3) and the motor housing (2) are both fixedly connected to the support shaft (10). The motor housing (2) is rotatably connected to the motor rotor hub (14). The motor rotor hub (14) and the support shaft (10) are rotatably connected through the motor rotor hub (14) bearing (11).

4. The electric drive wheel system based on multi-stage vibration reduction design according to claim 3, characterized in that: A rotor (15) is mounted on the side wall of the motor rotor hub (14), and a planetary gear reduction assembly (13) is also mounted on the motor rotor hub (14).

5. The electric drive wheel system based on multi-stage vibration reduction design according to claim 4, characterized in that: The planetary gear reduction assembly (13) includes a sun gear, planet gears, a planet carrier (6) and a gear ring. The sun gear is connected to the motor rotor hub (14). The gear ring is fixedly connected to the motor housing (2) through a flange. The planet gears are connected to the planet carrier (6) through planetary pins (12). The planet carrier (6) is connected to the hub (8) through connecting bolts (5) and a first vibration damping structure (401). The planet carrier (6) is connected to the support shaft (10) through a planet carrier bearing (7) to form a rotating pair.

6. The electric drive wheel system based on multi-stage vibration reduction design according to claim 5, characterized in that: A steering servo motor (16) is engaged on the steering knuckle (21), and the steering servo motor (16) is rigidly connected to the upper cross arm (18) through the steering motor support (17).

7. An electric drive wheel system based on multi-stage vibration reduction design according to claim 6, characterized in that: The steering servo motor (16) includes a worm gear reducer with self-locking function. The output shaft of the steering servo motor (16) meshes with the inner hole of the steering knuckle (21) through an involute spline, and the axis of the output shaft of the steering servo motor (16) passes through the rotation center of the steering knuckle (21) and the ball joint center of the lower cross arm (20).

8. An electric drive wheel system based on multi-stage vibration reduction design according to claim 7, characterized in that: The suspension system also includes an air spring and a magnetorheological damper (19). The air spring and the magnetorheological damper (19) are arranged in parallel. The working cylinder of the magnetorheological damper (19) is filled with magnetorheological fluid, and the damping force is changed stepwise through an electromagnetic coil.

9. An electric drive wheel system based on multi-stage vibration reduction design according to claim 8, characterized in that: The upper end of the steering knuckle (21) is connected to the left end of the upper cross arm (18), and the lower end is connected to the left end of the lower cross arm (20), forming two rotating joints. The right ends of the upper and lower cross arms (20) are connected to the vehicle frame through rotating joints. The lower end of the magnetorheological damper (19) forms a rotating pair with the lower cross arm (20), and the upper end is connected to the frame through a ball joint.

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