A non-contact magnetic wheel transmission structure for electric-assisted bicycles

Abstract

This utility model relates to the field of electric-assisted bicycle drive technology, and discloses a magnetic wheel non-contact transmission structure for electric-assisted bicycles, including: a drive motor and a magnetic wheel assembly; the output end of the drive motor is fixedly connected to a motor shaft; the magnetic wheel assembly consists of an inner rotor and an outer rotor, the inner rotor is fixedly connected to the motor shaft, and the outer rotor is disposed outside the inner rotor; the ratio of the number of magnetic pole pairs of the inner rotor to the number of magnetic pole pairs of the outer rotor is 4:19-22, and non-contact gear shifting is achieved through the magnetic pole pair differential effect, the speed ratio formula is: speed ratio = number of magnetic pole pairs of the outer rotor / number of magnetic pole pairs of the inner rotor; the surface of the magnetic wheel assembly is coated with a high-temperature resistant protective layer, which is an AlNiCo-epoxy resin composite coating. This application replaces the mechanical meshing gear transmission of the motor in the prior art with a magnetic wheel assembly, solving the problems of high gear noise, frequent vibration, short life and high maintenance cost of the existing transmission method.

Description

Technical Field

[0001] This utility model relates to the field of electric-assisted bicycle drive technology, and in particular to a magnetic wheel non-contact transmission structure for electric-assisted bicycles. Background Technology

[0002] With the rapid development of electric-assist bicycle technology, the transmission structure of the motor, the core component of its drive system, has attracted much attention. Currently, most electric-assist bicycles on the market rely on mechanical gears for their motor transmission. While this traditional transmission method meets basic riding needs to a certain extent, its inherent defects are becoming increasingly apparent as consumers' demands for riding experience gradually increase and the application scope of electric-assist bicycles continues to expand. This seriously restricts further leaps in the performance and quality of electric-assist bicycles.

[0003] Most existing mid-drive motors use mechanical gear transmission, which has the following drawbacks: high-frequency howling and dry friction noise: gear machining errors and lubrication failures lead to abnormal noise from tooth surface friction; load impact and vibration transmission: gear collisions produce a "clicking" sound when starting and climbing, and the vibration is amplified through the housing; short lifespan and high maintenance costs: gear wear requires frequent replacement, resulting in high costs over the entire life cycle.

[0004] Therefore, a new solution is needed to address the above problems. Summary of the Invention

[0005] This invention overcomes the shortcomings of the prior art and provides a non-contact magnetic wheel transmission structure for electric-assisted bicycles.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a magnetic wheel non-contact transmission structure for an electric-assisted bicycle, comprising: a drive motor and a magnetic wheel assembly; the output end of the drive motor is fixedly connected to a motor shaft; the magnetic wheel assembly comprises an inner rotor and an outer rotor, the inner rotor being fixedly connected to the motor shaft, and the outer rotor being disposed outside the inner rotor; the ratio of the number of magnetic pole pairs of the inner rotor to the number of magnetic pole pairs of the outer rotor is 4:19-22, and non-contact gear shifting is achieved through the magnetic pole pair differential effect, the speed ratio formula being: speed ratio = number of magnetic pole pairs of the outer rotor / number of magnetic pole pairs of the inner rotor; the surface of the magnetic wheel assembly is coated with a high-temperature resistant protective layer, the high-temperature resistant protective layer being an AlNiCo-epoxy resin composite coating.

[0007] In a preferred embodiment of this utility model, when applied to a hub motor, the magnetic wheel assembly further includes a passive rotor disposed outside the outer rotor, and the three are coaxially nested; the ratio of the number of magnetic pole pairs of the inner rotor to the outer rotor is 4:21, and the number of magnetic pole pairs of the passive rotor is 45.

[0008] In a preferred embodiment of this utility model, the diameter ratio of the inner rotor to the outer rotor is 1:4-1:4.5, and an air gap with a width of 0.5-2mm is provided between the inner rotor, the outer rotor, and the passive rotor.

[0009] In a preferred embodiment of this utility model, when applied to a mid-drive motor, the inner rotor and outer rotor are arranged in a 1:1 ratio, the outer rotor is connected to the bicycle crank, and the ratio of the number of magnetic pole pairs of the inner rotor and the outer rotor is 4:21.

[0010] In a preferred embodiment of this invention, the thickness of the AlNiCo-epoxy resin composite coating is 50-200 μm.

[0011] In a preferred embodiment of this utility model, the AlNiCo-epoxy resin composite coating is bonded to the surface of the magnet through a thermosetting process, with a curing temperature of 150-200℃.

[0012] In a preferred embodiment of this utility model, both the inner rotor and the outer rotor of the magnetic wheel assembly are made of neodymium iron boron magnets.

[0013] In a preferred embodiment of the present invention, the invention further includes a sensor for detecting the rotational speed and torque of the magnetic wheel assembly and a controller for controlling the operation of the electric-assisted bicycle system. The sensor is electrically connected to the controller of the electric-assisted bicycle, and the controller adjusts the output power of the motor in real time according to the sensor signal.

[0014] In a preferred embodiment of this invention, the controller further incorporates a collaborative control algorithm to intelligently optimize the transmission efficiency and power output of the magnetic wheel assembly based on information such as the rider's pedaling force, vehicle speed, and road conditions.

[0015] This utility model solves the defects existing in the background technology, and has the following beneficial effects:

[0016] This invention provides a mid-drive motor transmission solution with zero friction, low noise, and long lifespan by using a magnetic wheel assembly as the transmission structure of the motor. Through non-contact transmission of the magnetic wheels, it achieves a breakthrough in efficiency and reliability. Compared with the mechanical meshing gear transmission of the prior art, this application is based on the magnetic pole pair differential effect. The inner rotor and the outer rotor interact through magnetic fields to achieve non-contact power transmission. This magnetic coupling connection not only has high transmission efficiency but also extremely low noise during operation, effectively avoiding the meshing noise and vibration problems of traditional gear transmission. Moreover, the entire transmission process is free of mechanical contact friction, which effectively increases the service life of this application. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0018] Figure 1 This is the three-dimensional structure of the preferred embodiment 1 of this utility model. Figure 1 ;

[0019] Figure 2 The magnetic pole pair distribution of the preferred embodiment 1 of this utility model Figure 1 ;

[0020] Figure 3 This is the three-dimensional structure of the preferred embodiment 2 of this utility model. Figure 2 ;

[0021] Figure 4 The magnetic pole pair distribution of the preferred embodiment 2 of this utility model Figure 2 ;

[0022] In the diagram: 1. Drive motor; 2. Inner rotor; 3. Outer rotor; 4. Passive rotor. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0024] Example 1:

[0025] Example 1 is an embodiment of the application of a magnetic wheel non-contact transmission structure for electric-assisted bicycles in a hub motor, as described in this application. Figure 1 , Figure 2 As shown, it includes:

[0026] The system comprises a hub motor, a magnetic wheel assembly, and a tire. The magnetic wheel assembly includes an inner rotor 2, an outer rotor 3, and a driven rotor 4, all made of neodymium iron boron magnets, possessing magnetic properties. It is fixedly connected to the motor shaft at the output end of the hub motor. The inner rotor 2 is fixedly connected to the motor shaft, the outer rotor 3 is positioned outside the inner rotor 2, and the driven rotor 4 is coaxially arranged with the inner rotor 2. All three are nested coaxially, and the diameter ratio of the inner rotor 2 to the outer rotor 3 is 1:4 to 1:4.5. This diameter ratio facilitates the rational arrangement of the number of pole pairs of the inner rotor 2, outer rotor 3, and driven rotor 4, thereby achieving speed ratio control. The inner rotor 2 is connected to the motor shaft of the hub motor to provide the power source, while the outer rotor 3 transmits power. When the motor is running... The inner rotor 2 rotates under the driving force of the motor, and its speed is related to the operating state of the motor. The speed of the outer rotor 3 is determined by factors such as the ratio of the number of pole pairs of the inner rotor 2 to the number of pole pairs of the outer rotor 3, as well as the magnetic coupling relationship, thus achieving the corresponding speed ratio. The passive rotor 4 drives the roller of the electric-assisted bicycle to rotate, and the speed of the passive rotor 4 corresponds to that of the roller in a 1:1 ratio. The ratio of the number of pole pairs of the inner rotor 2 to the number of pole pairs of the outer rotor 3 is 4:21. The two achieve non-contact transmission and determine the corresponding speed ratio through the differential effect of the pole pairs. The specific speed ratio is determined by the ratio of the number of pole pairs of the two. The speed ratio formula is: Speed ​​ratio = Number of pole pairs of the outer rotor 3 / Number of pole pairs of the inner rotor 2. In the application of Embodiment 1, the inner rotor 2 is a 4-pole 8-magnet, the outer rotor 3 is a 21-pole 42-magnet, and the driven rotor 4 is a 45-pole 90-magnet. The speed ratio calculated according to the speed ratio formula is 42:8 = 5.25. However, in actual applications, due to the presence of air gaps (0.5-2mm) between the inner rotor 2 and the outer rotor 3, and between the outer rotor 3 and the driven rotor 4, as well as the influence of other actual working conditions, the actual speed ratio is approximately 5.28. This discrepancy between the actual and calculated speed ratio is normal and falls within the reasonable error range of the magnetic gear transmission system.

[0027] Furthermore, the surface of the magnetic wheel assembly is coated with a high-temperature resistant protective layer with a thickness of 50-200μm through a thermosetting process. Specifically, the high-temperature resistant protective layer is an AlNiCo-epoxy resin composite coating. The AlNiCo-epoxy resin composite coating on the surface of the magnetic wheel assembly ensures high-temperature resistance under long-term operation and complex working conditions, thus extending the service life of the magnetic wheel assembly.

[0028] Furthermore, the system is equipped with sensors and a controller. The sensors detect the rotational speed and torque of the magnetic wheel assembly in real time and transmit the signals to the controller. The controller has a built-in collaborative control algorithm that can intelligently adjust the motor's output power based on sensor signals and information such as the rider's pedaling force, speed, and road conditions. This optimizes the transmission efficiency and power output of the magnetic wheel assembly, ensuring that it provides precise and comfortable assistance to the rider in different riding scenarios. For example, when riding at a constant speed on a flat road, the controller will appropriately reduce the motor's output power to operate in energy-saving mode; while when climbing or starting, the controller will increase the motor's output power to provide stronger power support, helping the rider easily cope with different road conditions.

[0029] When the motor starts, the inner rotor 2 begins to rotate under the driving force of the motor. Based on the differential effect of magnetic pole pairs, the inner rotor 2 and the outer rotor 3 interact through magnetic fields, achieving non-contact power transmission and driving the outer rotor 3 to rotate. The rotation of the outer rotor 3 further drives the passive rotor 4 to rotate, thereby driving the bicycle wheels and propelling the vehicle forward. Because the inner rotor 2, outer rotor 3, and passive rotor 4 are all magnetically coupled, there is no mechanical contact friction throughout the transmission process. This results in high transmission efficiency and extremely low noise during operation, effectively avoiding the meshing noise and vibration problems of traditional gear transmissions.

[0030] Example 2:

[0031] Example 2 is an embodiment of the application of a non-contact magnetic wheel transmission structure for electric-assisted bicycles in a mid-drive motor, as described in this application. Figure 3 , Figure 4 As shown, the transmission principle is similar to that of Example 1, both utilizing the differential effect of magnetic pole pairs to achieve non-contact transmission. However, they differ in application structure and transmission relationship. The difference lies in the fact that the magnetic wheel set consists of an inner rotor 2 and an outer rotor 3 in a 1:1 ratio. The inner rotor 2 is fixedly connected to the motor shaft of the central motor, and the outer rotor 3 is connected to the crank system of the bicycle, transmitting power to the crank, which in turn drives the bicycle sprocket and chain to rotate, thereby causing the wheels to rotate.

[0032] Specifically, the inner rotor 2 has 4 pole pairs and 8 magnets, while the outer rotor 3 has 21 pole pairs and 42 magnets. Therefore, the calculated speed ratio is 42:8 = 5.25. In actual applications, since an air gap is also provided between the inner rotor 2 and the outer rotor 3, the actual speed ratio is also 5.28. Depending on the structure, size, motor power, and riding requirements of the electric-assist bicycle, the inner rotor 2 and outer rotor 3 can be designed with different numbers of pole pairs to achieve different speed ratios. For example, when the motor has strong driving force and requires a high output speed, the number of pole pairs in the inner rotor 2 can be appropriately reduced or the number of pole pairs in the outer rotor 3 can be increased. Conversely, when the motor has weak driving force and requires a large torque output, the number of pole pairs in the inner rotor 2 can be appropriately increased or the number of pole pairs in the outer rotor 3 can be decreased, thereby adjusting the speed ratio to adapt to different motor and riding conditions.

[0033] When the motor is running, the inner rotor 2 drives the outer rotor 3 to rotate synchronously, and the efficient transmission of power is achieved by relying on the magnetic coupling relationship between the inner and outer rotors 3. Due to the use of non-contact transmission, the friction loss and noise generation in traditional mid-drive motor gear transmission are greatly reduced, improving the reliability and service life of the transmission system. Furthermore, by adjusting the ratio of the number of magnetic pole pairs of the inner rotor 2 and the outer rotor 3, the transmission ratio can be flexibly set to meet the needs of different riders and adapt to various riding scenarios.

[0034] Based on the preferred embodiments of this utility model described above, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A magnetic wheel non-contact transmission structure for an electrically assisted bicycle, characterized in that, include: A drive motor (1) and a magnetic wheel assembly; the output end of the drive motor (1) is fixedly connected to a motor shaft; the magnetic wheel assembly includes an inner rotor (2) and an outer rotor (3), the inner rotor (2) is fixedly connected to the motor shaft, and the outer rotor (3) is located outside the inner rotor (2); the ratio of the number of magnetic pole pairs of the inner rotor (2) to the number of magnetic pole pairs of the outer rotor (3) is 4:19-22, and non-contact speed change is achieved through the magnetic pole pair differential effect. The speed ratio formula is: speed ratio = number of magnetic pole pairs of the outer rotor (3) / number of magnetic pole pairs of the inner rotor (2); the surface of the magnetic wheel assembly is coated with a high-temperature resistant protective layer, which is an AlNiCo-epoxy resin composite coating.

2. A magnetic wheel non-contact transmission structure for an electrically assisted bicycle according to claim 1, characterized in that: When applied to a hub motor, the magnetic wheel assembly also includes a passive rotor (4) disposed outside the outer rotor (3), and the three are coaxially nested; the ratio of the number of magnetic pole pairs of the inner rotor (2) to the outer rotor (3) is 4:21, and the number of magnetic pole pairs of the passive rotor (4) is 45.

3. A magnetic wheel non-contact transmission structure for an electrically assisted bicycle according to claim 2, characterized in that: The diameter ratio of the inner rotor (2) to the outer rotor (3) is 1:4-1:4.

5. An air gap is provided between the inner rotor (2), the outer rotor (3) and the passive rotor (4), with a gap width of 0.5-2mm.

4. A magnetic wheel non-contact transmission structure for an electrically assisted bicycle according to claim 1, characterized in that: When applied to a mid-drive motor, the inner rotor (2) and the outer rotor (3) are arranged in a 1:1 ratio, the outer rotor (3) is connected to the bicycle crank, and the ratio of the number of magnetic pole pairs of the inner rotor (2) and the outer rotor (3) is 4:

21.

5. A magnetic wheel non-contact transmission structure for an electrically assisted bicycle according to claim 1, characterized in that: The thickness of the AlNiCo-epoxy resin composite coating is 50-200μm.

6. A magnetic wheel non-contact transmission structure for an electrically assisted bicycle according to claim 1, characterized in that: The inner rotor (2) and outer rotor (3) of the magnetic wheel assembly are both made of neodymium iron boron magnets.

7. A magnetic wheel non-contact transmission structure for an electric-assisted bicycle according to claim 1, characterized in that: It also includes a sensor for detecting the rotational speed and torque of the magnetic wheel assembly and a controller for controlling the operation of the electric-assist bicycle system. The sensor is electrically connected to the controller of the electric-assist bicycle, and the controller adjusts the output power of the motor in real time according to the sensor signal.

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