A compact omnidirectional steering wheel

Abstract

This invention provides a compact omnidirectional steering wheel, belonging to the field of drive technology for trackless land vehicles. It includes a steering wheel bracket with a through-type mounting cavity along its axial direction. One end of the mounting cavity faces the tire side, and the other end is a free end facing away from the tire side. A steering drive unit is arranged in the region near the free end of the mounting cavity. The steering drive unit includes a permanent magnet synchronous motor and a parallel shaft reducer, with a pinion gear at the output end of the parallel shaft reducer. A mounting opening is provided on the top of the steering wheel bracket, corresponding to the radial side of the mounting cavity, and communicates with the mounting cavity. A slewing bearing is arranged at the mounting opening, including a large gear that meshes with a small gear. The rotation center of the slewing bearing coincides with the width center of the tire. The center distance between the small gear and the large gear can be adapted to the tire width so that the tire can be positioned close to the outer side of the equipment platform.

Description

Technical Field

[0001] This invention relates to the field of drive technology for trackless land vehicles, and particularly to a compact omnidirectional steering wheel. Background Technology

[0002] A steering wheel is an omnidirectional drive component that integrates a steering wheel bracket, steering drive unit, slewing bearing, travel drive unit, and tires, enabling 360° omnidirectional steering and adapting to scenarios such as AGVs and transport vehicles. For example, patent document with application number CN202211124134.5 discloses such an omnidirectional steering wheel. Similar to traditional technologies, its steering uses a combination of a servo motor and a planetary reducer, while its travel uses a combination of a permanent magnet synchronous motor and a planetary or parallel shaft reducer.

[0003] Therefore, the following problems exist:

[0004] The structural design of the steering drive planetary reducer restricts its installation position and center distance, resulting in a large diameter of the slewing bearing. To avoid tire wear and improve steering flexibility during steering, the center of the tire width must coincide with the slewing bearing's rotation center. As a result, the tire is completely recessed into the equipment platform while still meeting the steering wheel installation requirements, reducing the stability of the equipment platform.

[0005] The travel drive uses a permanent magnet synchronous motor. The characteristic of permanent magnet synchronous motors is that the radial dimension is small but the axial dimension is large. This results in a long axial dimension of the entire travel drive, which is exposed in the horizontal direction of the steering wheel. This reduces the passability of the whole machine when traveling. Especially when the steering wheel turns, there are interference positions in the axial length direction of the travel drive around the rotation center of the slewing bearing, which greatly reduces the flexibility. Summary of the Invention

[0006] The present invention aims to solve the above-mentioned technical problems by providing a compact omnidirectional steering wheel.

[0007] The technical solution of this invention is a compact omnidirectional steering wheel, including a steering wheel bracket. The steering wheel bracket has a through-type mounting cavity along its axial direction. One end of the mounting cavity faces the tire side, and the other end is a free end facing away from the tire side. A steering drive unit is disposed in the region near the free end of the mounting cavity. The steering drive unit includes a permanent magnet synchronous motor and a parallel shaft reducer. A pinion is disposed at the output end of the parallel shaft reducer. A mounting opening is provided on the top of the steering wheel bracket, corresponding to the radial side of the mounting cavity. The mounting opening communicates with the mounting cavity. A slewing bearing is disposed at the mounting opening. The slewing bearing includes a large gear that meshes with the pinion. The rotation center of the slewing bearing coincides with the width center of the tire; the center distance between the pinion and the gear can be adapted to the width of the tire so that the tire can be arranged close to the outer side of the equipment platform; the area of ​​the mounting cavity facing the tire is connected to the annular receiving space of the tire, and a travel drive unit is jointly arranged in the mounting cavity and the annular receiving space. The travel drive unit includes an axial flux motor and a planetary reducer. The axial flux motor is embedded in the annular receiving space, the planetary reducer is housed in the mounting cavity, and the output end of the planetary reducer is connected to the tire. The axial flux motor and the planetary reducer are coaxially fixedly connected.

[0008] In one embodiment, the mounting cavity includes a first mounting cavity and a second mounting cavity arranged sequentially along the axial direction. The second mounting cavity is located between the first mounting cavity and the tire. The second mounting cavity is an axially extended section of the first mounting cavity facing the tire side. The second mounting cavity is coaxially arranged with and connected to the first mounting cavity. The permanent magnet synchronous motor and the parallel shaft reducer are housed in the first mounting cavity, and the planetary reducer is housed in the second mounting cavity.

[0009] In one embodiment, the permanent magnet synchronous motor and the parallel shaft reducer are arranged coaxially and are connected by a coupling. The top of the steering wheel bracket is provided with a first mounting hole and a second mounting hole. The parallel shaft reducer is fixedly connected to the steering wheel bracket by fasteners passing through the first mounting hole and the second mounting hole.

[0010] In one embodiment, a cover plate is detachably connected to the top of the steering wheel bracket.

[0011] In one embodiment, the free end of the mounting cavity is provided with a sealing end cap.

[0012] In one embodiment, the inner ring sidewall of the slewing bearing has a plurality of evenly distributed connecting holes, the axis of the connecting holes being parallel to the central axis of the slewing bearing, and the slewing bearing being detachably connected to the steering wheel bracket via the connecting holes and bolts.

[0013] In one embodiment, the steering wheel bracket is further provided with a steering angle detection unit, which includes an encoder. The encoder is fixedly installed in the first mounting cavity, and a detection gear is connected to the detection shaft of the encoder. The detection gear meshes with the large gear.

[0014] In one embodiment, a protective cover is detachably connected to the top of the steering wheel bracket. The protective cover extends toward one side of the slewing bearing to form two opposing protective ears. One of the protective ears covers the outside of the pinion, and the other protective ear covers the outside of the detection gear. The protective cover has an arc-shaped clearance space corresponding to the meshing area of ​​the large gear.

[0015] In one embodiment, the tire is a solid rubber tire.

[0016] In one embodiment, the steering wheel bracket is integrally die-cast.

[0017] The advantages of this invention compared to the prior art are that this compact omnidirectional steering wheel, through a unique structural design, organically integrates steering drive, travel drive, steering wheel bracket, tires, and slewing bearing. Specifically, the steering drive adopts a combination of a permanent magnet synchronous motor and a parallel shaft reducer, and the travel drive adopts a combination of an axial flux motor and a planetary reducer. This solves many technical pain points of existing steering wheels, such as excessive size, poor passability, insufficient platform stability, and inflexible steering, and brings many beneficial effects such as compact structure, excellent power performance, and wide applicability. Attached Figure Description

[0018] Figure 1 Exploded view of a compact omnidirectional steering wheel provided for an embodiment of the present invention;

[0019] Figure 2 A schematic diagram of the steering wheel bracket provided for an embodiment of the present invention;

[0020] Figure 3 A schematic diagram of the structure of the protective cover provided for an embodiment of the present invention;

[0021] Figure 4 A schematic diagram of the structure of a compact omnidirectional steering wheel provided for an embodiment of the present invention.

[0022] In the diagram: 1. Steering wheel bracket; 2. Mounting cavity; 21. First mounting cavity; 22. Second mounting cavity; 3. Steering drive unit; 31. Permanent magnet synchronous motor; 32. Parallel shaft reducer; 4. Pinion; 5. Mounting port; 6. Slewing bearing; 7. Large gear; 8. Annular receiving space; 9. Travel drive unit; 91. Axial flux motor; 92. Planetary reducer; 921. Output end; 10. Tire; 11. First mounting hole; 12. Second mounting hole; 13. Cover plate; 14. Sealing end cap; 15. Connecting hole; 16. Steering angle detection unit; 17. Encoder; 18. Detection gear; 19. Protective cover; 20. Protective ear; 23. Arc-shaped clearance space; 24. Adjustment port; 25. Mounting base; 26. Adjustment motor. Detailed Implementation

[0023] The above and other embodiments and advantages of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0024] In one implementation, such as Figure 1 As shown.

[0025] The compact omnidirectional steering wheel provided in this embodiment includes a steering wheel bracket 1. The steering wheel bracket 1 has a through-type mounting cavity 2 along its axial direction. One end of the mounting cavity 2 faces the tire 10, and the other end is a free end facing away from the tire 10. A steering drive unit 3 is arranged in the region near the free end of the mounting cavity 2. The steering drive unit 3 includes a permanent magnet synchronous motor 31 and a parallel shaft reducer 32. A pinion 4 is provided at the output end of the parallel shaft reducer 32. A mounting port 5 is provided on the top of the steering wheel bracket 1, corresponding to the radial side of the mounting cavity 2. The mounting port 5 communicates with the mounting cavity 2. A slewing bearing 6 is provided at the mounting port 5. The slewing bearing 6 includes a large gear 7, which meshes with the pinion 4. The rotation center of the slewing bearing 6 is... The width centers of the tires 10 coincide; the center distance between the pinion 4 and the gear 7 can be adapted to the width of the tires 10 so that the tires 10 can be arranged close to the outer side of the equipment platform; the area of ​​the mounting cavity 2 facing the tires 10 is connected to the annular receiving space 8 of the tires 10. The mounting cavity 2 and the annular receiving space 8 of the tires 10 are jointly provided with a walking drive unit 9. The walking drive unit 9 includes an axial flux motor 91 and a planetary reducer 92. The axial flux motor 91 is embedded in the annular receiving space 8 inside the tires 10. The planetary reducer 92 is housed in the mounting cavity 2, and the output end 921 of the planetary reducer 92 is connected to the tires 10. The axial flux motor 91 and the planetary reducer 92 are coaxially fixedly connected.

[0026] In this embodiment, the working principle of the compact omnidirectional steering wheel is as follows:

[0027] During steering, the permanent magnet synchronous motor 31 in the steering drive unit 3 starts, outputting power to the parallel shaft reducer 32. The parallel shaft reducer 32 reduces and increases the torque of the power, which is then transmitted to the large gear 7 of the slewing bearing 6 through the pinion 4 at its output end. This drives the slewing bearing 6 to rotate around its rotation center, thereby enabling the entire steering wheel bracket 1 and tire 10 to achieve 360° omnidirectional steering. Since the input and output shafts of the parallel shaft reducer 32 are arranged in parallel, their center distance can be flexibly adapted and set according to the width of the tire 10 during the design phase. That is, by precisely adjusting the meshing center distance between the pinion 4 and the large gear 7, and based on this, setting the diameter of the large gear 7 of the slewing bearing 6 to the minimum reasonable size that matches the width of the tire 10, the tire 10 can be arranged as close as possible to the outer side of the equipment platform.

[0028] During operation, the axial flux motor 91 in the walking drive unit 9 starts, outputting power to the planetary reducer 92. After the planetary reducer 92 completes the reduction and torque increase, it directly drives the tire 10 to rotate, realizing the walking action of the steering wheel. Since the axial flux motor 91 itself has the characteristic of short axial dimension, it is assembled into the tire 10 with an internal annular receiving space 8, and is completely embedded in the annular receiving space 8 inside the tire 10, thus avoiding the motor being exposed on the outside of the tire 10, effectively shortening the overall horizontal dimension of the steering wheel.

[0029] In this embodiment, the beneficial effects of the compact omnidirectional steering wheel are as follows:

[0030] First, it breaks through the technical limitations of traditional steering drive by adopting a combination of permanent magnet synchronous motor 31 and parallel shaft reducer 32. Compared with the conventional combination of servo motor and planetary reducer 92 in the existing technology, the parallel shaft reducer 32 can achieve flexible matching of the center distance between the pinion 4 and the large gear 7 through its own structural characteristics. This overcomes the technical pain points of the fixed center distance of the planetary reducer 92, which results in the excessively large diameter of the slewing bearing 6 and the inward shrinkage of the tire 10, thus improving the stability of the equipment platform.

[0031] Secondly, the axial flux motor 91 is applied to the travel drive unit 9 of the steering wheel and is embedded entirely inside the tire 10, overcoming the technical bias in this field that "the motor needs to be exposed and the conventional permanent magnet synchronous motor 31 with a small radial dimension should be preferred." The short axial dimension of the axial flux motor 91 not only solves the interference problem caused by the excessive axial length of traditional motors and improves the overall passability, but its high power density also enhances the travel drive capability within the limited space inside the tire 10.

[0032] Finally, the 360° omnidirectional steering combined with the compact structural design enables the steering wheel to turn in place, move horizontally, and move diagonally in any direction, making it particularly suitable for scenarios with limited workspace, such as AGVs and transport vehicles, thus expanding the application range of the steering wheel.

[0033] In summary, the compact omnidirectional steering wheel in this embodiment organically integrates the steering drive unit 3, the travel drive unit 9, the steering wheel bracket 1, the tire 10, and the slewing bearing 6 through structural design. This solves several long-standing technical problems of existing steering wheels, such as excessive size, poor passability, insufficient platform stability, and inflexible steering. It brings beneficial effects such as compact structure, excellent power performance, and wide applicability.

[0034] In one implementation, such as Figure 1 As shown.

[0035] The compact omnidirectional steering wheel provided in this embodiment includes a mounting cavity 2 comprising a first mounting cavity 21 and a second mounting cavity 22 arranged sequentially along the axial direction. The second mounting cavity 22 is located between the first mounting cavity 21 and the tire 10. The second mounting cavity 22 is an axially extended section within the first mounting cavity 21 toward the tire 10. The second mounting cavity 22 is coaxially arranged with and connected to the first mounting cavity 21. The permanent magnet synchronous motor 31 and the parallel shaft reducer 32 are housed within the first mounting cavity 21, and the planetary reducer 92 is housed within the second mounting cavity 22.

[0036] In this embodiment, the mounting cavity 2 is divided axially into a first mounting cavity 21 and a second mounting cavity 22, which respectively house the permanent magnet synchronous motor 31 and parallel shaft reducer 32 of the steering drive unit 3, and the planetary reducer 92 of the travel drive unit 9, thus achieving efficient utilization of the internal space of the steering wheel bracket 1. This partitioned arrangement avoids interference between components, thereby significantly improving the overall compactness of the compact omnidirectional steering wheel.

[0037] In one implementation, such as Figure 1 and Figure 2 As shown.

[0038] The compact omnidirectional steering wheel provided in this embodiment has a permanent magnet synchronous motor 31 and a parallel shaft reducer 32 arranged coaxially and connected by a coupling. The top of the steering wheel bracket 1 is provided with a first mounting hole 11 and a second mounting hole 12. The parallel shaft reducer 32 is fixedly connected to the steering wheel bracket 1 by fasteners passing through the first mounting hole 11 and the second mounting hole 12.

[0039] In this embodiment, the permanent magnet synchronous motor 31 and the parallel shaft reducer 32 are arranged coaxially and connected by a coupling, effectively solving the problem of achieving efficient and stable power transmission in a compact space. The coaxial arrangement maximizes the use of axial space, making the overall structure of the steering drive unit 3 more compact and easier to integrate into the first mounting cavity 21 of the steering wheel bracket 1. The coupling effectively compensates for minor alignment deviations between the motor and the reducer, and also ensures the smoothness of the transmission process. Furthermore, by opening the first mounting hole 11 and the second mounting hole 12 on the top of the steering wheel bracket 1 and using fasteners to firmly fix the parallel shaft reducer 32, the positional stability of the reducer in the working state is ensured, vibration is effectively suppressed, and the precise meshing of the pinion 4 and the gear 7 is guaranteed, thus improving the reliability of the steering drive unit 3.

[0040] In one implementation, such as Figure 1 As shown.

[0041] The compact omnidirectional steering wheel provided in this embodiment has a cover plate 13 detachably connected to the top of the steering wheel bracket 1.

[0042] In this embodiment, a detachable cover plate 13 is provided on the top of the steering wheel bracket 1, allowing convenient and quick access to critical components inside the steering wheel bracket 1 when inspection, maintenance, or replacement is required. Operators can directly operate the internal components simply by removing the cover plate 13. Furthermore, the cover plate 13 effectively protects the internal precision components from external environmental influences during normal operation, ensuring the long-term stable operation of the steering wheel.

[0043] In one implementation, such as Figure 1 As shown.

[0044] The compact omnidirectional steering wheel provided in this embodiment has a sealing end cap 14 at the free end of the mounting cavity 2.

[0045] In this embodiment, a sealing end cap 14 is provided at the free end of the mounting cavity 2, which can effectively isolate the steering drive unit 3, walking drive unit 9 and other components inside the steering wheel bracket 1 from the external environment. This improves the dustproof and waterproof capabilities of the compact omnidirectional steering wheel and avoids the corrosion and wear of internal components such as the permanent magnet synchronous motor 31, parallel shaft reducer 32, axial flux motor 91 and planetary reducer 92 caused by dust and moisture.

[0046] In one implementation, such as Figure 1 As shown.

[0047] The compact omnidirectional steering wheel provided in this embodiment has a plurality of evenly distributed connecting holes 15 on the inner ring sidewall of the slewing bearing 6. The axis of the connecting holes 15 is parallel to the central axis of the slewing bearing 6. The slewing bearing 6 is detachably connected to the steering wheel bracket 1 by bolts through the connecting holes 15.

[0048] In this embodiment, the connection between the slewing bearing 6 and the steering wheel bracket 1 becomes flexible and efficient. When the slewing bearing 6 needs maintenance due to wear or other reasons, it can be easily and quickly removed from the steering wheel bracket 1 by loosening the bolts for inspection or replacement of the new slewing bearing 6, without the need for large-scale disassembly of the entire steering wheel assembly.

[0049] In one implementation, such as Figure 1 As shown.

[0050] The compact omnidirectional steering wheel provided in this embodiment is further provided with a steering wheel bracket 1 and a steering angle detection unit 16. The steering angle detection unit 16 includes an encoder 17, which is fixedly installed in the first mounting cavity 21. A detection gear 18 is connected to the detection shaft of the encoder 17, and the detection gear 18 meshes with the large gear 7.

[0051] In this embodiment, a steering angle detection unit 16 is added to the steering wheel bracket 1. This unit includes an encoder 17 fixedly installed in the first mounting cavity 21. Through the meshing of the detection gear 18 with the large gear 7, real-time and accurate detection of the steering wheel's turning angle is achieved. The encoder 17 is cleverly integrated into the first mounting cavity 21, avoiding additional external installation space requirements and maintaining the overall compactness of the steering wheel. Simultaneously, through the direct meshing of the detection gear 18 with the large gear 7, the rotation angle of the slewing bearing 6 can be obtained, i.e., the actual steering angle of the steering wheel. This provides feedback signals to the steering control system of the steering wheel, enabling the control system to achieve closed-loop control of the steering wheel, significantly improving the steering accuracy and response speed of the steering wheel.

[0052] In one implementation, such as Figure 3 As shown.

[0053] The compact omnidirectional steering wheel provided in this embodiment has a protective cover 19 detachably connected to the top of the steering wheel bracket 1. The protective cover 19 extends toward the side of the slewing bearing 6 to form two opposing protective ears 20. One of the protective ears 20 covers the outside of the pinion 4, and the other protective ear 20 covers the outside of the detection gear 18. The protective cover 19 has an arc-shaped clearance space 23 corresponding to the meshing area of ​​the large gear 7.

[0054] In this embodiment, the protective cover 19 and its protective ears 20 effectively isolate the meshing components of the steering drive unit 3, such as the pinion 4, the slewing bearing 6, and the detection gear 18, from the external environment. This reduces the risk of dust, debris, and other foreign objects entering the gear meshing area, thereby effectively preventing premature wear, corrosion, and jamming of the gears. Simultaneously, the protective ears 20 provide localized enhanced protection for the pinion 4 and the detection gear 18, improving the overall impact resistance of the steering mechanism. The arc-shaped clearance space 23 ensures that the protective cover 19 provides comprehensive protection without affecting the normal rotation function of the slewing bearing 7.

[0055] In one embodiment, the tire 10 of the compact omnidirectional steering wheel is a solid rubber tire 10. The robust and durable characteristics of the solid rubber tire 10 enable it to adapt to harsher working environments.

[0056] In one embodiment, the steering wheel bracket 1 of the compact omnidirectional steering wheel is integrally die-cast. The integrally die-cast steering wheel bracket 1 improves the overall structural strength and rigidity, effectively avoiding potential stress concentration and structural deformation problems.

[0057] In one implementation, such as Figure 4 As shown.

[0058] The compact omnidirectional steering wheel provided in this embodiment includes a steering wheel bracket 1. The steering wheel bracket 1 has a through-type mounting cavity 2 along its axial direction. One end of the mounting cavity 2 is arranged facing the tire 10, and the other end is a free end facing away from the tire 10. A steering drive unit 3 is arranged in the region near the free end of the mounting cavity 2. The steering drive unit 3 includes a permanent magnet synchronous motor 31 and a parallel shaft reducer 32. A pinion 4 is provided at the output end of the parallel shaft reducer 32. A mounting port 5 is opened on the top of the steering wheel bracket 1 on the radial side corresponding to the mounting cavity 2. The mounting port 5 is connected to the mounting cavity 2. A slewing bearing 6 is provided at the mounting port 5. The slewing bearing 6 includes a large gear 7, which meshes with the small gear 4. The rotation center of the slewing bearing 6 coincides with the width center of the tire 10. An adjustment port 24 is also provided on the top of the steering wheel bracket 1. The adjustment port 24 extends along the center distance adjustment direction between the small gear 4 and the large gear 7. A mounting base 25 is slidably disposed in the adjustment port 24. The parallel shaft reducer 32 is mounted on the mounting base 25. An adjustment motor 26 is provided on the steering wheel bracket 1. The adjustment motor 26 is connected to the mounting base 25 to drive the mounting... The seat 25 slides along the adjustment port 24 to adjust the center distance between the pinion 4 and the large gear 7. The center distance between the pinion 4 and the large gear 7 can be pre-adapted and adjusted according to the width of the tire 10 so that the tire 10 can be arranged close to the outer side of the equipment platform. The steering wheel is also equipped with a steering angle detection unit 16 and a controller. The steering angle detection unit 16 is used to collect the actual steering angle signal in real time and send it to the controller. The controller controls the adjustment motor 26 to operate according to the deviation between the actual steering angle and the theoretical steering angle, so as to compensate and adjust the center distance between the pinion 4 and the large gear 7. The tire 10 is maintained in an engagement position that matches its current width. The area of ​​the mounting cavity 2 facing the tire 10 is connected to the annular receiving space 8 of the tire 10. The mounting cavity 2 and the annular receiving space 8 are jointly provided with a travel drive unit 9. The travel drive unit 9 includes an axial flux motor 91 and a planetary reducer 92. The axial flux motor 91 is embedded in the annular receiving space 8. The planetary reducer 92 is housed in the mounting cavity 2, and the output end 921 of the planetary reducer 92 is connected to the tire 10. The axial flux motor 91 and the planetary reducer 92 are coaxially fixedly connected.

[0059] In this embodiment, the large gear 7 and small gear 4 are pre-selected according to the width of the selected tire 10 to ensure the initial meshing state of the gears. This is a coarse adjustment of the center distance, so that the tire 10 is arranged close to the outer side of the equipment platform. During the steering process, the actual rudder angle signal is collected in real time by the rudder angle detection unit 16 and sent to the controller. The controller compares the actual rudder angle with the theoretical rudder angle to obtain the rudder angle deviation value. This deviation value can reflect the abnormal state of the center distance deviating from the preset adaptation position. Based on this, the controller drives the adjustment motor 26 to perform compensation adjustment on the center distance between the small gear 4 and the large gear 7. This is the compensation center distance. The two adjustments share the same set of adjustment structure to keep the center distance at the optimal meshing position that matches the current tire 10 width, thereby ensuring the steering accuracy of the steering wheel.

[0060] The specific embodiments described above further illustrate the inventive purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, or improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A compact omnidirectional steering wheel, characterized in that, Including the steering wheel bracket, The steering wheel bracket has a through-type mounting cavity along its axial direction. One end of the mounting cavity faces the tire side and the other end is a free end away from the tire side. A steering drive unit is arranged in the area near its free end inside the mounting cavity. The steering drive unit includes a permanent magnet synchronous motor and a parallel shaft reducer. A pinion is provided at the output end of the parallel shaft reducer. The top of the steering wheel bracket has a mounting opening on the radial side corresponding to the mounting cavity. The mounting opening is connected to the mounting cavity. A slewing bearing is provided at the mounting opening. The slewing bearing includes a large gear that meshes with a small gear. The rotation center of the slewing bearing coincides with the width center of the tire. The center distance between the small gear and the large gear can be adapted to the width of the tire so that the tire can be arranged close to the outer side of the equipment platform. The area facing the tire inside the mounting cavity is connected to the annular receiving space of the tire. A walking drive unit is jointly provided in the mounting cavity and the annular receiving space. The walking drive unit includes an axial flux motor and a planetary reducer. The axial flux motor is embedded in the annular receiving space, and the planetary reducer is housed in the mounting cavity. The output end of the planetary reducer is connected to the tire. The axial flux motor and the planetary reducer are coaxially and fixedly connected. The top of the steering wheel bracket is also provided with an adjustment port, which extends along the center distance adjustment direction between the pinion and the gear. A mounting seat is slidably disposed in the adjustment port, and the parallel shaft reducer is mounted on the mounting seat. An adjustment motor is provided on the steering wheel bracket, and the adjustment motor is connected to the mounting seat to drive the mounting seat to slide along the adjustment port for adjusting the center distance between the pinion and the gear. The steering wheel is also equipped with a steering angle detection unit and a controller. The steering angle detection unit is used to collect the actual steering angle signal in real time and send it to the controller. The controller controls the adjustment motor to operate according to the deviation between the actual steering angle and the theoretical steering angle, and adjusts the center distance between the pinion and the gear to compensate for the center distance and keep it in the meshing position that matches the current tire width.

2. The compact omnidirectional steering wheel according to claim 1, characterized in that, The mounting cavity includes a first mounting cavity and a second mounting cavity arranged sequentially along the axial direction. The second mounting cavity is located between the first mounting cavity and the tire. The second mounting cavity is an axially extended section of the first mounting cavity facing the tire side. The second mounting cavity is coaxially arranged and connected to the first mounting cavity. The permanent magnet synchronous motor and the parallel shaft reducer are housed in the first mounting cavity, and the planetary reducer is housed in the second mounting cavity.

3. The compact omnidirectional steering wheel according to claim 2, characterized in that, The permanent magnet synchronous motor and the parallel shaft reducer are arranged coaxially and are connected by a coupling. The top of the steering wheel bracket is provided with a first mounting hole and a second mounting hole. The parallel shaft reducer is fixedly connected to the steering wheel bracket by fasteners passing through the first mounting hole and the second mounting hole.

4. The compact omnidirectional steering wheel according to claim 3, characterized in that, The top of the steering wheel bracket is detachably connected to a cover plate.

5. The compact omnidirectional steering wheel according to claim 1, characterized in that, The free end of the mounting cavity is provided with a sealing end cap.

6. The compact omnidirectional steering wheel according to claim 1, characterized in that, The inner ring sidewall of the slewing bearing has a number of evenly distributed connecting holes. The axis of the connecting holes is parallel to the central axis of the slewing bearing. The slewing bearing is detachably connected to the steering wheel bracket via the connecting holes and bolts.

7. The compact omnidirectional steering wheel according to claim 2, characterized in that, The steering wheel bracket is also equipped with a steering angle detection unit, which includes an encoder. The encoder is fixedly installed in the first mounting cavity. A detection gear is connected to the detection shaft of the encoder, and the detection gear meshes with the large gear.

8. The compact omnidirectional steering wheel according to claim 7, characterized in that, The top of the steering wheel bracket is detachably connected to a protective cover. The protective cover extends toward one side of the slewing bearing to form two opposing protective ears. One of the protective ears covers the outside of the pinion, and the other protective ear covers the outside of the detection gear. The protective cover has an arc-shaped clearance space corresponding to the meshing area of ​​the large gear.

9. The compact omnidirectional steering wheel according to claim 1, characterized in that, The tire is a solid rubber tire.

10. The compact omnidirectional steering wheel according to claim 1, characterized in that, The steering wheel bracket is integrally die-cast.

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