Miniature electric drive wheel

Abstract

The utility model discloses a miniature electric drive wheel, including: stator subassembly, rotor subassembly, outer casing, circuit board, circlip and induction magnetic steel, rotor subassembly includes hollow shaft, motor casing and motor magnetic ring, hollow shaft is through bearing relative fixed base coaxial rotation connection, hollow shaft has the assembly space, induction magnetic steel assembly space is equipped with the motor magnetic ring, the motor shell is connected with the hollow shaft, the motor magnetic ring is connected with the motor shell, a riveting point is arranged at the outer end of the hollow shaft, a limiting ring groove is formed in the inner end of the hollow shaft, the outer end of the hollow shaft is riveted with the outer tire shell through the riveting point, the inner side portion of the elastic check ring is clamped into the limiting ring groove, and the outer side portion of the elastic check ring abuts against the rotating portion of the bearing. And a magnetic field sensor is arranged on the circuit board and is used for acquiring a position signal of the induction magnetic steel and adjusting the relative position of the stator assembly and the rotor assembly according to the position signal. According to the miniature electric drive wheel, the running stability performance and the safety performance of the miniature electric drive wheel are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electric drive wheels, in particular to a miniature electric drive wheel. Background Art

[0002] With the development and progress of science and technology, the drive of wheels has evolved from the traditional way of rotation driven by a drive shaft to a self-driven way of an electric motor composed of a stator and a rotor. The stator is fixedly installed on the main body that needs to be docked, and the outer layer of the rotor is additionally installed with a tire skin to achieve electric self-driven rotation. The size of the wheel can be the size of a toy wheel or even smaller, which is called a micro electric drive wheel.

[0003] However, the micro electric-driven wheels in the prior art have zero-speed drift and even the risk of low-temperature failure due to the small size of the micro motor, small torsional torque, high rotation speed and insufficient control accuracy. The biggest problem with the micro electric-driven wheels in the prior art is that the axial space of the motor is limited, which makes it easy for the shaft to decouple, that is, the stator and rotor separate and fall off from each other. Utility Model Content

[0004] Based on this, it is necessary to provide a micro electric drive wheel to solve the technical problem of how to avoid zero-speed drift and the de-axle phenomenon in which the stator and rotor separate and fall off from each other.

[0005] A micro electric drive wheel, comprising: a stator assembly, a rotor assembly, an outer tire shell, a circuit board, an elastic retaining ring and an induction magnetic steel.

[0006] The stator assembly includes a fixed base, a stator core and a coil winding, wherein the fixed base is used to be installed on the docking body, the stator core is connected to the fixed base, the coil winding is wound on the stator core, and the circuit board is installed on the fixed base.

[0007] The rotor assembly includes a hollow shaft, a motor housing and a motor magnetic ring. The hollow shaft passes through the fixed base and is coaxially rotatably connected relative to the fixed base through a bearing.

[0008] The hollow shaft has an assembly space inside, the induction magnetic steel is received and installed in the assembly space, the motor housing is connected to the hollow shaft, the motor magnetic ring is connected to the motor housing and is arranged around the stator core,

[0009] The outer end of the hollow shaft is provided with a rivet point, the inner end of the hollow shaft is provided with a limit ring groove, the outer end of the hollow shaft is riveted to the outer tire shell through the rivet point, the inner side of the elastic retaining ring is inserted into the limit ring groove, and the outer side of the elastic retaining ring is in contact with the rotating part of the bearing.

[0010] A magnetic field sensor is arranged on the circuit board, and the magnetic field sensor is used to obtain the position signal of the induction magnetic steel and adjust the relative position of the stator assembly and the rotor assembly according to the position signal.

[0011] In one embodiment, the inner end of the hollow shaft is adjacent to the circuit board, and the induction magnetic steel is disposed adjacent to the inner end of the hollow shaft.

[0012] In one embodiment, the hollow shaft is a hollow cylindrical structure with openings on both sides, the radial cross-section of the assembly space is circular, the induction magnetic steel is a cylindrical structure, the outer diameter of the induction magnetic steel is equal to the inner diameter of the hollow shaft, and the induction magnetic steel is connected to the hollow shaft by interference fit.

[0013] In one embodiment, the bearing includes a first bearing and a second bearing, the first bearing and the second bearing are arranged side by side and are both connected to the hollow shaft and the fixed base, and the outer side of the elastic retaining ring abuts against the rotating part of the second bearing.

[0014] In one embodiment, the inner diameter of the first bearing is equal to the inner diameter of the second bearing, and the outer diameter of the first bearing is greater than the outer diameter of the second bearing.

[0015] In one embodiment, the motor housing includes a motor housing bottom and a motor housing wall, and the motor housing bottom and the motor housing wall together form a hollow cylindrical structure with an opening on one side. A receiving portion is provided in the central area of ​​the motor housing bottom, and a circular channel is opened in the receiving portion. The hollow shaft passes through the circular channel and is connected to the motor housing bottom.

[0016] In one embodiment, the motor housing bottom and the motor housing wall are integrally formed.

[0017] In one embodiment, the motor housing bottom and the motor housing wall together form a receiving space, and the fixed base, the stator core and the coil winding are all located in the receiving space.

[0018] In one embodiment, the circuit board is located on the opening side of the hollow cylindrical structure formed by the motor housing bottom and the motor housing wall, the circuit board is a circular plate-shaped structure, and the outer diameter of the circuit board is equal to the inner diameter of the opening of the hollow cylindrical structure formed by the motor housing bottom and the motor housing wall.

[0019] In one embodiment, the outer tire shell includes a counterweight block, a left end cover, a right end cover and an outer tire skin, the counterweight block is provided with a counterweight installation through hole, the counterweight block is also provided with a counterweight riveting fit groove radially extending from the outer periphery of the counterweight installation through hole, the hollow shaft passes through the counterweight installation through hole, the rivet point is connected to the counterweight riveting fit groove by riveting, the left end cover and the right end cover are respectively connected to the motor housing to jointly accommodate the stator assembly, the rotor assembly, the circuit board, the elastic retaining ring and the induction magnet, and the outer tire skin is respectively connected to the left end cover and the right end cover.

[0020] The above-mentioned micro electric drive wheel, by installing the induction magnet in the inner hollow assembly space of the hollow shaft, the magnetic field sensor on the circuit board will obtain the position signal of the induction magnet, and record the position signal accordingly when the rotor assembly is in the zero position. When the position of the rotor assembly deviates during operation, the relative position of the stator assembly and the rotor assembly is adjusted according to the position signal to realize the electronic commutation of the motor, thereby avoiding the phenomenon that the position of the rotor assembly is inconsistent with the original zero position during operation; at the same time, the rivet point of the hollow shaft can achieve a close fit between the hollow shaft and the motor housing, and with the cooperation of the limit ring groove and the elastic retaining ring, the structural stability of the hollow shaft, the motor housing and the fixed base is greatly improved, effectively avoiding the situation where the shaft is easily derailed due to the limited axial space of the motor, thereby improving the operation stability and safety performance of the micro electric drive wheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of a micro electric drive wheel in one embodiment;

[0022] Figure 2 for Figure 1 A schematic structural diagram of the micro electric drive wheel in another perspective in the embodiment shown;

[0023] Figure 3 A schematic diagram of a partially disassembled structure of a micro electric drive wheel in one embodiment;

[0024] Figure 4 for Figure 1 A schematic structural diagram of the micro electric drive wheel in another perspective in the embodiment shown;

[0025] Figure 5 for Figure 4 A schematic cross-sectional structural diagram of the micro electric drive wheel AA in the illustrated embodiment;

[0026] Figure 6 A schematic cross-sectional view of a tire casing in one embodiment;

[0027] Figure 7is a schematic cross-sectional structural diagram of a stator assembly in one embodiment;

[0028] Figure 8 is a schematic cross-sectional structural diagram of a rotor assembly in one embodiment;

[0029] Fig. 9 A schematic diagram of a partial structure of a micro electric drive wheel in one embodiment;

[0030] Fig.10 A schematic diagram of the structure of a motor housing in one embodiment;

[0031] Fig.11 for Fig.10 A schematic structural diagram of the motor housing from another perspective in the illustrated embodiment;

[0032] Fig.12 for Fig.10 A schematic structural diagram of the motor housing from another perspective in the illustrated embodiment;

[0033] Fig.13 for Fig.12 A schematic cross-sectional structural diagram of the motor housing BB in the illustrated embodiment. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned purpose, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth so as to fully understand the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below. In the description of the utility model, it is necessary to understand that the orientation or position relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or position relationship shown in the accompanying drawings, only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the utility model.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0036] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0038] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0039] Please also read Figures 1 to 5In one embodiment of the utility model, a micro electric drive wheel 10 is provided, and the micro electric drive wheel 10 comprises: a stator assembly 100, a rotor assembly 200, a tire shell 300, a circuit board 400, an elastic retaining ring 500 and an induction magnet 600. The stator assembly 100 and the rotor assembly 200 cooperate with each other, the stator assembly 100 is powered by the circuit board 400, the rotor assembly 200 rotates relative to the stator assembly 100 during operation, and the tire shell 300 is installed outside the rotor assembly 200, which provides the stator assembly 100, the rotor assembly 200, etc. with aesthetic appearance, support and protection, and increases the friction against the ground.

[0040] like Figure 3 , Figure 5 , Figure 7 as well as Fig. 9 As shown, the stator assembly 100 includes a fixed base 110, a stator core 120, and a coil winding 130. The fixed base 110 is used to be installed on a docking body, which may be a vehicle body, a cabinet, etc. The fixed base 110 remains fixed relative to the docking body during the working process of the micro electric drive wheel 10. The stator core 120 is connected to the fixed base 110, the coil winding 130 is wound on the stator core 120, and the circuit board 400 is installed on the fixed base 110.

[0041] like Figure 3 , Figure 5 , Figure 7 , Figure 8 as well as Fig. 9 As shown, the rotor assembly 200 includes a hollow shaft 210, a motor housing 220 and a motor magnetic ring 230. The hollow shaft 210 passes through the fixed base 110 and is connected to the fixed base 110 coaxially and rotatably via the bearing 140. In this way, the hollow shaft 210 is sleeved on the bearing 140, and the bearing 140 is installed on the fixed base 110. The hollow shaft 210 can rotate relative to the fixed base 110 under the action of the bearing 140. It can be understood that the overall shape of the fixed base 110 is also a cylindrical structure to adapt to the wheel structure. The fixed base 110 is provided with an installation channel 111, and the fixed base 110 is provided with an installation groove for the bearing 140 in the installation channel 111. The hollow shaft 210 passes through the installation channel 111 and is connected to the bearing 140. Generally, the installation channel 111 is provided at the center of the cylinder of the fixed base 110, so that the hollow shaft 210 can rotate coaxially relative to the fixed base 110 via the bearing 140.

[0042] The hollow shaft 210 has an assembly space 211 in the hollow, and the induction magnet 600 is received and installed in the assembly space 211. The motor housing 220 is connected to the hollow shaft 210. The motor magnetic ring 230 is connected to the motor housing 220 and is disposed around the stator core 120.

[0043] A rivet point 212 is provided at the outer end of the hollow shaft 210, and a limiting ring groove 213 is provided at the inner end of the hollow shaft 210. The outer end of the hollow shaft 210 is riveted to the outer tire shell 300 through the rivet point 212, and the inner side of the elastic retaining ring 500 is inserted into the limiting ring groove 213, and the outer side of the elastic retaining ring 500 abuts against the rotating part of the bearing 140.

[0044] A magnetic field sensor is disposed on the circuit board 400 , and the magnetic field sensor is used to obtain a position signal of the induction magnet 600 and adjust the relative position of the stator assembly 100 and the rotor assembly 200 according to the position signal.

[0045] The above-mentioned micro electric drive wheel 10, by installing the induction magnet 600 in the inner hollow assembly space 211 of the hollow shaft 210, the magnetic field sensor on the circuit board 400 will obtain the position signal of the induction magnet 600, and record the position signal accordingly when the rotor assembly 200 is at the zero position. When the position of the rotor assembly 200 deviates during operation, the relative position of the stator assembly 100 and the rotor assembly 200 is adjusted according to the position signal to realize the electronic commutation of the motor, thereby avoiding the phenomenon that the position of the rotor assembly 200 is inconsistent with the original zero position during operation; at the same time, the rivet point 212 of the hollow shaft 210 can realize the close fit between the hollow shaft 210 and the motor housing 220, and, with the cooperation of the limiting ring groove 213 and the elastic retaining ring 500, the structural stability of the hollow shaft 210, the motor housing 220 and the fixed base 110 is greatly improved, which effectively avoids the situation that the shaft is easily derailed due to the limited axial space of the motor, thereby improving the operation stability and safety performance of the micro electric drive wheel.

[0046] In order to enable the magnetic field sensor on the circuit board 400 to better capture the magnetic field of the induction magnet 600, in one embodiment, the inner end of the hollow shaft 210 is adjacent to the circuit board 400, and the induction magnet 600 is disposed adjacent to the inner end of the hollow shaft 210. In other words, the induction magnet 600 is disposed adjacent to the circuit board 400. In this way, within a relatively short distance, the magnetic field sensor can better capture the magnetic field of the induction magnet 600, thereby improving the stability of the operation of the circuit board 400 and providing a better structural design for the precise positioning of the circuit board 400.

[0047] In order to better assemble the induction magnet 600, in one embodiment, the hollow shaft 210 is a hollow cylindrical structure with openings on both sides, the radial cross section of the assembly space 211 is circular, the induction magnet 600 is a cylindrical structure, the outer diameter of the induction magnet 600 is equal to the inner diameter of the hollow shaft 210, and the induction magnet 600 is connected to the hollow shaft 210 by interference fit. In this way, the induction magnet 600 can be stably and firmly installed in the hollow shaft 210, and the position of the induction magnet 600 in the hollow shaft 210 is relatively fixed in the absence of a large external force, and the induction magnet 600 can stably provide a magnetic field signal when the micro electric drive wheel is electrically working.

[0048] It can be understood that the utility model provides a variable precision control solution, the induction magnet is used to provide magnetic field signals, the hollow shaft provides assembly space for the magnet, the drive board, i.e., the circuit board, can be equipped with a magnetic encoder, which can also be changed to a Hall sensor as needed to achieve a variable precision control solution and solve the zero-speed drift of the motor. The design of the hollow shaft also provides precise positioning for the drive board.

[0049] like Figure 7 As shown, in one embodiment, the bearing 140 includes a first bearing 141 and a second bearing 142, which are arranged side by side and are both connected to the hollow shaft 210 and the fixed base 110, and the outer side of the elastic ring 500 abuts against the rotating part of the second bearing 142. In this way, the double bearing design can better support the hollow shaft 210, so that the hollow shaft 210 is more balanced, so that the hollow shaft 210 can operate in a stable and firm state.

[0050] Furthermore, the inner diameter of the first bearing 141 is equal to the inner diameter of the second bearing 142, and the outer diameter of the first bearing 141 is greater than the outer diameter of the second bearing 142. The fixing base 110 is provided with a mounting groove for the first bearing 141 and a mounting groove for the second bearing 142 in the mounting channel 111, respectively. In this way, firstly, the first bearing 141 with a larger outer diameter can provide greater support for the hollow shaft 210, and the micro electric drive wheel will inevitably encounter some vibrations or impacts during operation. Since the outer side of the elastic ring 500 abuts against the rotating part of the second bearing 142, when vibration or impact occurs, the elastic ring 500 will rub against the second bearing 142, and the second bearing 142 will inevitably be damaged in the long run. Therefore, in this embodiment, the design of large and small bearings is cleverly used. On the one hand, the double bearing design can better support the hollow shaft 210. On the other hand, when the second bearing 142 is damaged and needs to be repaired or replaced, the first bearing 141 with a larger outer diameter can provide greater support for the hollow shaft 210, and will not cause the position of the hollow shaft 210 to be offset. In addition, the second bearing 142 with a smaller outer diameter has a lower cost when it needs to be replaced, and is more cost-effective.

[0051] like Figures 3 to 9 As shown, in one embodiment, the outer tire shell 300 includes a counterweight block 310, a left end cover 320, a right end cover 330 and an outer tire skin 340, the counterweight block 310 is provided with a counterweight installation through hole 311, and the counterweight block 310 is also provided with a counterweight riveting press fitting groove 312 extending radially from the outer peripheral edge of the counterweight installation through hole 311, the hollow shaft 210 is provided with the counterweight installation through hole 311, and the rivet point 212 is connected with the counterweight riveting press fitting groove 312 by riveting. It can be understood that the counterweight block 310 is a disc structure, the counterweight installation through hole 311 is located in the central area of ​​the counterweight block 310, and the counterweight riveting press fitting groove 312 is coaxially arranged with the counterweight installation through hole 311. Preferably, the counterweight block 310 is tightly connected with the hollow shaft 210 through the counterweight installation through hole 311. In this way, after the rivet point 212 is riveted with the counterweight 310 , the counterweight 310 can be tightly abutted against the motor housing 220 . At the same time, with the cooperation of the elastic retaining ring 500 , the rotor assembly 200 and the outer tire shell 300 form a tight whole with a stable structure.

[0052] Further, the left end cover 320 and the right end cover 330 are connected to the motor housing 220 respectively. Preferably, the left end cover 320 and the right end cover 330 are connected to the motor housing 220 in a tightly fitting manner by gluing. The left end cover 320 and the right end cover 330 jointly accommodate the stator assembly 100, the rotor assembly 200, the circuit board 400, the elastic retaining ring 500 and the induction magnet 600. The outer tire skin 340 is connected to the left end cover 320 and the right end cover 330 respectively. Preferably, the outer tire skin 340 is also glued to the left end cover 320 and the right end cover 330 by gluing. The outer shape structure of the left and right end covers can be further optimized, such as the setting of the left end cover 320 and the right end cover 330 can change the appearance design according to the customer's demand for the product, so as to seek diversified and diversified wheels; at the same time, the outer tire skin is tightly glued to the left and right end covers to increase the friction between the wheel drive motor, i.e., the micro electric drive wheel, and the ground, and different material sizes can be selected according to the application scenario.

[0053] like Figures 10 to 13 As shown, in one embodiment, the motor housing 220 includes a motor housing bottom 221 and a motor housing wall 222, which are formed together as a hollow cylindrical structure with one side open, and a receiving portion 223 is provided in the central area of ​​the motor housing bottom 221, and a circular channel 224 is provided in the receiving portion 223, and the hollow shaft 210 passes through the circular channel 224 and is connected to the motor housing bottom 221. Further, the motor housing bottom 221 and the motor housing wall 222 together form a receiving space 225, and the fixed base 110, the stator core 120 and the coil winding 130 are all located in the receiving space 225.

[0054] In this embodiment, in order to increase the contact area between the motor housing 220 and the hollow shaft 210 and improve the stability after the motor housing 220 and the hollow shaft 210 are tightly combined, a receiving portion 223 is provided in the central area of ​​the motor housing bottom 221. Preferably, the central area of ​​the motor housing bottom 221 is recessed toward the opening and is formed with an inclined portion 2231, the inclined portion 2231 is extended in a roundabout direction in the radial direction to form a roundabout portion 2232, the roundabout portion 2232 is extended in parallel in a direction away from the opening to form a circular portion 2233, the inclined portion 2231, the roundabout portion 2232 and the circular portion 2233 constitute the receiving portion 223, and the channel of the circular portion 2233 is a circular channel 224. The receiving portion 223 is formed by an integrated molding design. In this way, the receiving portion 223 has a strong structural strength, a larger contact area with the hollow shaft 210, and makes the wheel more stable during operation.

[0055] To further improve the structural strength, in one embodiment, the motor housing bottom 221 and the motor housing wall 222 are integrally formed. The motor housing bottom 221 and the motor housing wall 222 are integrally formed during the casting or manufacturing process, which improves the structural strength and facilitates the process.

[0056] like Figure 3 and Figure 5 As shown, in one embodiment, the circuit board 400 is located at the opening side of the hollow cylindrical structure formed by the motor housing bottom 221 and the motor housing wall 222. The circuit board 400 is a circular plate-like structure, and the outer diameter of the circuit board 400 is equal to the inner diameter of the opening of the hollow cylindrical structure formed by the motor housing bottom 221 and the motor housing wall 222. In this way, on the one hand, the circuit board 400 can play a shielding role to prevent foreign matter from directly entering the stator assembly 100. On the other hand, the components of the circuit board 400 can be arranged on the side facing the motor housing bottom 221. At the same time, the circuit board 400 is provided with a clearance gap so that the mounting foot of the fixed base 110 passes through the circuit board 400 and is connected and fixed to the docking body. At the same time, the interface of the circuit board 400 is also arranged on the side facing away from the motor housing bottom 221. This can make the entire structure more compact and convenient for installation and connection.

[0057] It can be understood that the micro wheel drive motor provided in each of the above embodiments is designed to ensure a large driving torque at a low speed, overcome the zero-speed drift phenomenon of the motor, achieve high-precision control, and can operate in harsh environments with a low failure rate. In addition, the utility model adds metal rivets and a clamping ring, i.e., an elastic retaining ring, to the structure, and uses technology to achieve the anti-shaft function in a limited space, which is safer and more reliable.

[0058] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A miniature electric drive wheel, characterized in that: include: Stator assembly, rotor assembly, outer casing, circuit board, elastic retaining ring and induction magnet, The stator assembly includes a fixed base, a stator core and a coil winding, wherein the fixed base is used to be installed on the docking body, the stator core is connected to the fixed base, the coil winding is wound on the stator core, and the circuit board is installed on the fixed base. The rotor assembly includes a hollow shaft, a motor housing and a motor magnetic ring. The hollow shaft passes through the fixed base and is coaxially rotatably connected relative to the fixed base through a bearing. The hollow shaft has an assembly space inside, the induction magnetic steel is received and installed in the assembly space, the motor housing is connected to the hollow shaft, the motor magnetic ring is connected to the motor housing and is arranged around the stator core, The outer end of the hollow shaft is provided with a rivet point, the inner end of the hollow shaft is provided with a limit ring groove, the outer end of the hollow shaft is riveted to the outer tire shell through the rivet point, the inner side of the elastic retaining ring is inserted into the limit ring groove, and the outer side of the elastic retaining ring is in contact with the rotating part of the bearing. A magnetic field sensor is arranged on the circuit board, and the magnetic field sensor is used to obtain the position signal of the induction magnetic steel and adjust the relative position of the stator assembly and the rotor assembly according to the position signal.

2. The micro electric drive wheel according to claim 1, characterized in that: The inner end of the hollow shaft is adjacent to the circuit board, and the induction magnetic steel is arranged adjacent to the inner end of the hollow shaft.

3. The micro electric drive wheel according to claim 2, characterized in that: The hollow shaft is a hollow cylindrical structure with openings on both sides, the radial cross-section of the assembly space is circular, the induction magnetic steel is a cylindrical structure, the outer diameter of the induction magnetic steel is equal to the inner diameter of the hollow shaft, and the induction magnetic steel is connected to the hollow shaft by interference fit.

4. The micro electric drive wheel according to claim 1, characterized in that: The bearing comprises a first bearing and a second bearing, the first bearing and the second bearing are arranged side by side and are both connected to the hollow shaft and the fixed base, and the outer side of the elastic retaining ring abuts against the rotating part of the second bearing.

5. The micro electric drive wheel according to claim 4, characterized in that: The inner diameter of the first bearing is equal to the inner diameter of the second bearing, and the outer diameter of the first bearing is greater than the outer diameter of the second bearing.

6. The micro electric drive wheel according to claim 1, characterized in that: The motor housing includes a motor housing bottom and a motor housing wall, wherein the motor housing bottom and the motor housing wall together form a hollow cylindrical structure with an opening on one side, a receiving portion is provided in the central area of ​​the motor housing bottom, a circular channel is opened in the receiving portion, and the hollow shaft passes through the circular channel and is connected to the motor housing bottom.

7. The micro electric drive wheel according to claim 6, characterized in that: The motor housing bottom and the motor housing wall are integrally formed.

8. The micro electric drive wheel according to claim 6, characterized in that: The motor housing bottom and the motor housing wall together form a receiving space, and the fixed base, the stator core and the coil winding are all located in the receiving space.

9. The micro electric drive wheel according to claim 8, characterized in that: The circuit board is located at the opening side of the hollow cylindrical structure formed by the motor housing bottom and the motor housing wall. The circuit board is a circular plate-shaped structure, and the outer diameter of the circuit board is equal to the inner diameter of the opening of the hollow cylindrical structure formed by the motor housing bottom and the motor housing wall.

10. The micro electric drive wheel according to claim 1, characterized in that: The outer tire shell includes a counterweight block, a left end cover, a right end cover and an outer tire skin. The counterweight block is provided with a counterweight installation through hole. The counterweight block is also provided with a counterweight riveting fit groove radially extending from the outer periphery of the counterweight installation through hole. The hollow shaft passes through the counterweight installation through hole. The rivet point is connected to the counterweight riveting fit groove by riveting. The left end cover and the right end cover are respectively connected to the motor housing to jointly accommodate the stator assembly, the rotor assembly, the circuit board, the elastic retaining ring and the induction magnet. The outer tire skin is respectively connected to the left end cover and the right end cover.

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