An ultra-thin wheel hub motor

Abstract

The application relates to the technical field of hub motors, in particular to an ultrathin hub motor which comprises a soft rubber wheel body, an end cover and a motor body, the soft rubber wheel body is provided with an opening, the motor body is built in the soft rubber wheel body, the end cover is in clamping cooperation with the soft rubber wheel body, the motor body comprises a stator, a rotor, a bearing and an electrostatic anti-interference assembly, the electrostatic anti-interference assembly comprises an annular circuit board and a plurality of convex teeth, the annular circuit board is fixed in the coil former inside of the stator of the motor body in a same-plane embedding mode, the plurality of convex teeth are arranged in a plurality of groups, the plurality of groups of the convex teeth are arranged in an inward extending mode along the inner ring of the annular circuit board and are in pressure joint cooperation with the rotor bearing of the motor body, a complete electrostatic discharge loop of a rotor shaft-bearing outer ring-stator-circuit board ground end is formed, electrostatic accumulation is reduced, and the application has the characteristics of improving the anti-static interference capability.

Description

Technical Field

[0001] This application relates to the field of hub motor technology, and in particular to an ultra-thin hub motor. Background Technology

[0002] Ultra-thin hub motors are a type of drive technology that integrates the motor directly inside the wheel. With its special flat structure design, it achieves efficient energy conversion in a compact space and is often used in emerging fields such as new energy vehicles or robotic vacuum cleaners.

[0003] In related technologies, hub motors typically include a hub, end caps, a motor, and an anti-static interference device. The anti-static interference device consists of a ring circuit board and protruding teeth. The ring circuit board is installed inside the stator coil frame of the motor, with components integrated on both sides, and the grounding terminal is selected as the negative terminal. The protruding teeth are evenly distributed on the inner ring of the ring circuit board, with a metal layer plated on the surface, and abut against the side wall of the motor rotor bearing, forming a complete electrostatic discharge circuit from the rotor shaft to the bearing side wall, the stator, and the grounding terminal of the circuit board.

[0004] Existing hub motors have the following problems: because they often operate in extreme working environments such as vibration, water immersion, and high temperature, poor contact may occur between the convex teeth and the outer ring of the motor rotor bearing, thereby affecting the normal operation of the anti-static interference device. Summary of the Invention

[0005] To improve the anti-static interference capability, this application provides an ultra-thin hub motor.

[0006] The ultra-thin hub motor provided in this application adopts the following technical solution:

[0007] An ultra-thin hub motor includes a soft rubber wheel body, an end cap, and a motor body. The soft rubber wheel body is open, and the motor body is housed within it. The end cap is snap-fitted into the soft rubber wheel body. The motor body includes a stator, a rotor, a bearing, and an electrostatic discharge (ESD) suppression assembly. The ESD suppression assembly includes an annular circuit board and protruding teeth. The annular circuit board is fixed to the inner side of the stator's coil frame in a coplanar embedded manner. Several protruding teeth are provided, extending inward along the inner ring of the annular circuit board and pressing against the outer ring of the bearing.

[0008] By adopting the above scheme, the convex tooth applies radial pressure to the rotor bearing of the motor body and makes close contact with it, forming a complete electrostatic discharge circuit from the rotor shaft to the outer ring of the bearing, the stator, and the ground terminal of the circuit board, thereby reducing static electricity accumulation and improving the device's anti-static interference capability and operational stability.

[0009] Preferably, the toothed teeth and the outer ring of the bearing have an interference fit.

[0010] The above solution utilizes the elastic deformation of the protruding teeth to generate a continuous clamping force, combining mechanical locking and low-resistance conductivity. The frictional torque generated by the interference fit resists circumferential slippage during rotor rotation, reducing fretting wear between the bearing and the protruding teeth.

[0011] Preferably, at least three protruding teeth are provided, and the protruding teeth are distributed at equal angular intervals along the inner ring of the annular circuit board.

[0012] By adopting the above scheme, multi-channel parallel discharge of static electricity is achieved, reducing contact resistance. The three-point support evenly disperses the radial load of the bearing, reducing the risk of stress concentration at a single point.

[0013] Preferably, the surface of the protruding teeth is uniformly covered with a metal coating.

[0014] By adopting the above scheme, the efficiency of static electricity discharge is improved, while the physical and chemical protection performance of the protruding teeth is also enhanced.

[0015] Preferably, a snap-fit ​​groove is provided on the inner wall of the rotor near the end, the snap-fit ​​groove is arranged horizontally circumferentially, and a snap-fit ​​ring is provided on the bottom side wall of the end cover corresponding to the snap-fit ​​groove.

[0016] By adopting the above solution, the groove wall of the snap-fit ​​groove abuts against the outer wall of the snap-fit ​​ring to form a mechanical stop, which restricts the axial displacement of the end cover and reduces the occurrence of end cover movement when the hub motor is running at high speed.

[0017] Preferably, the snap rings are arranged in segments along the bottom sidewall of the end cap and are spaced at equal intervals.

[0018] By adopting the above solution, the end cap can be assembled and disengaged by rotating at a smaller angle compared to a complete ring.

[0019] Preferably, the snap ring and the end cap are integrally formed.

[0020] By adopting the above solution, the subsequent bonding or assembly steps are optimized, making it suitable for mass production. The one-piece molded structure has no weak seams, stronger fatigue resistance, and is easy to replace after wear.

[0021] Preferably, the snap-fit ​​ring and the snap-fit ​​groove do not make complete contact.

[0022] By adopting the above solution and allowing for machining tolerances in the parts, the assembly difficulty is further reduced.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. The convex teeth apply radial pressure to the rotor bearing of the motor body and make close contact with it, forming a complete electrostatic discharge circuit from the rotor shaft to the outer ring of the bearing, the stator, and the ground terminal of the circuit board, thereby reducing static electricity accumulation and improving the anti-static interference capability of the device.

[0025] 2. Improved the operational stability and vibration resistance of the device;

[0026] 3. It reduces the assembly precision of the device and improves convenience. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0028] Figure 2 This is a schematic diagram of the usage environment of the electrostatic discharge immunity component according to an embodiment of this application.

[0029] Figure 3 This is a cross-sectional structural diagram of an embodiment of this application.

[0030] Figure 4 This is a schematic diagram of the overall structure of the end cap in the embodiment of this application.

[0031] Explanation of reference numerals in the attached drawings: 1. Soft rubber wheel body; 2. End cap; 21. Snap-fit ​​ring; 3. Motor body; 31. Stator; 311. Snap-fit ​​groove; 32. Rotor; 33. Bearing; 4. Electrostatic discharge isolation component; 41. Raised tooth; 42. Annular circuit board. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0033] This application discloses an ultra-thin hub motor. (Refer to...) Figure 1-2 An ultra-thin hub motor includes a soft rubber wheel body 1, an end cap 2, and a motor body 3. The soft rubber wheel body 1 is open, and the motor body 3 is installed inside the soft rubber wheel body 1. The end cap 2 is snapped into the soft rubber wheel body 1. During operation, the soft rubber wheel body 1 absorbs the impact of the road surface through elastic deformation, and the snap-fit ​​structure with the end cap 2 ensures the sealing of the motor and reduces the intrusion of dust or other impurities.

[0034] Specifically, the motor body 3 includes a stator 31, a rotor 32, a bearing 33, and an electrostatic discharge (ESD) suppression component 4. The ESD suppression component 4 includes an annular circuit board 42 and a tooth 41. The annular circuit board 42 is mounted inside the coil frame of the stator 31 and is located on the same plane as the coil frame of the stator 31.

[0035] Furthermore, in this embodiment, three protruding teeth 41 are provided. The three protruding teeth 41 extend inward along the inner ring of the annular circuit board 42 and are press-fitted with the outer ring of the bearing 33. The press-fitting of the protruding teeth 41 with the outer ring of the bearing 33 has an interference fit.

[0036] Therefore, during assembly, the tooth 41 continuously generates radial pressure by forcibly pressing down on the outer ring of the bearing 33, and forms a mechanical interlock by relying on the elastic deformation of the metal. The frictional torque generated by the interference fit can resist the circumferential slippage when the rotor 32 rotates, reducing the fretting wear between the outer ring of the bearing 33 and the tooth 41.

[0037] Furthermore, after the convex tooth 41 makes close contact with the outer ring of the bearing 33, a complete electrostatic discharge circuit is formed from the rotor 32 shaft to the outer ring of the bearing 33, the stator 31, and the ground of the circuit board. This reduces the accumulation of electrostatic charge generated by the continuous friction between the soft rubber wheel 1 and the road surface during the operation of the device, and reduces the occurrence of electrostatic accumulation damaging the precision components of the motor body 3. At the same time, the multi-point pressing of the convex tooth 41 disperses the stress, reduces the occurrence of failure of a single interference surface under bumpy road conditions, effectively reduces the vibration amplitude, and comprehensively improves the anti-static interference capability and operational stability of the device.

[0038] On the other hand, the three protrusions 41 are distributed at equal angles along the inner ring of the annular circuit board 42, that is, the included angle between each protrusion 41 is 120°. Through multi-point pressing, three-point support is formed, which evenly disperses the radial load of the bearing 33, reduces the risk of single-point stress concentration, and at the same time, realizes multi-channel parallel discharge of static electricity, effectively reducing contact resistance.

[0039] Furthermore, the surface of the tooth 41 is uniformly covered with a metal coating (not shown in the attached figure) to improve the efficiency of static electricity discharge. At the same time, it can also reduce the wear rate of the interference fit surface between the tooth 41 and the bearing 33, and play a role in isolating moisture and acidic substances, reducing the occurrence of electrochemical reactions in the tooth 41, and extending the service life of the tooth 41.

[0040] On the other hand, refer to Figure 3-4 The inner wall of the rotor 32 near the end has a snap-fit ​​groove 311, which is arranged horizontally in the circumferential direction.

[0041] Furthermore, the bottom sidewall of the end cap 2 is integrally formed with a snap ring 21 corresponding to the snap groove 311. In this embodiment, the snap ring 21 is arranged in six equal segments, and each segment of the snap ring 21 is arranged at equal intervals.

[0042] Therefore, by integrally molding the snap ring 21 with the end cap 2, the assembly time is shortened, the production efficiency is improved, and it is easy to replace after wear, which reduces the mold development cost and after-sales maintenance cost. Moreover, the integral molding structure has no weak joints and has stronger fatigue resistance. At the same time, it is easy to control the cumulative tolerance of the segmented snap ring 21, thereby reducing the difficulty of adjusting the dynamic balance of the rotor 32.

[0043] Furthermore, the groove wall of the snap-fit ​​groove 311 abuts against the outer wall of the snap-fit ​​ring 21 to form a mechanical stop, which restricts the axial displacement of the end cover 2. The circumferentially distributed snap-fit ​​surfaces evenly distribute the torque of the rotor 32, improve the overall bending strength, and reduce the occurrence of the end cover 2 moving around when the hub motor is running at high speed.

[0044] Furthermore, the snap-fit ​​structure does not require bolt fixing, and compared to a complete ring, the end cap 2 can be assembled and disassembled by rotating at a smaller angle.

[0045] Specifically, the snap ring 21 and the snap groove 311 do not make complete contact, so that the load is transmitted through multiple discrete contact points, reducing plastic deformation or cracks caused by stress concentration. The contact gap allows the snap ring 21 to undergo slight deformation under load or thermal expansion, so as to reduce impact or jamming and thus extend service life.

[0046] The implementation principle of an ultra-thin hub motor according to an embodiment of this application is as follows: The device uses multiple protruding teeth 41 to press and engage with the outer ring of the bearing 33 of the rotor 32 inside the motor body 3, forming a complete electrostatic discharge circuit from the rotor 32 shaft to the outer ring of the bearing 33, the stator 31, and the ground end of the circuit board. This reduces the accumulation of static electricity and minimizes the impact of static electricity accumulation on the precision components inside the motor body 3. At the same time, the segmented snap-fit ​​ring 21 on the bottom side wall of the end cover 2 and the snap-fit ​​groove 311 opened on the inner wall of the stator 31 of the motor body 3 interlock with each other, improving the connection strength to adapt to extreme working conditions. This comprehensively improves the anti-static interference capability and operational stability of the device.

[0047] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An ultra-thin hub motor, characterized in that, The device includes a soft rubber wheel body (1), an end cap (2), and a motor body (3). The soft rubber wheel body (1) is open, and the motor body (3) is built into the soft rubber wheel body (1). The end cap (2) is snapped into the soft rubber wheel body (1). The motor body (3) includes a stator (31), a rotor (32), a bearing (33), and an electrostatic interference suppression component (4). The electrostatic interference suppression component (4) includes an annular circuit board (42) and protruding teeth (41). The annular circuit board (42) is fixed to the inner side of the coil frame of the stator (31) in a plane-embedded manner. Several protruding teeth (41) are provided. Several protruding teeth (41) extend inward along the inner ring of the annular circuit board (42) and are pressed into the outer ring of the bearing (33).

2. The ultra-thin hub motor according to claim 1, characterized in that, The protruding tooth (41) and the outer ring of the bearing (33) are press-fitted with an interference fit.

3. The ultra-thin hub motor according to claim 2, characterized in that, At least three protruding teeth (41) are provided, and the protruding teeth (41) are distributed at equal angular intervals along the inner ring of the annular circuit board (42).

4. The ultra-thin hub motor according to claim 3, characterized in that, The surface of the protruding tooth (41) is uniformly covered with a metal coating.

5. The ultra-thin hub motor according to claim 1, characterized in that, The inner wall of the rotor (32) near the end has a snap-fit ​​groove (311) which is arranged horizontally in the circumferential direction. The bottom side wall of the end cover (2) is provided with a snap-fit ​​ring (21) corresponding to the snap-fit ​​groove (311).

6. The ultra-thin hub motor according to claim 5, characterized in that, The snap rings (21) are arranged in segments and at equal intervals along the bottom sidewall of the end cap (2).

7. The ultra-thin hub motor according to claim 6, characterized in that, The snap ring (21) and the end cap (2) are integrally formed.

8. The ultra-thin hub motor according to claim 6, characterized in that, The snap-fit ​​ring (21) and the snap-fit ​​groove (311) do not make complete contact.

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