Hub motor applied to electric scooter

Abstract

The utility model provides a wheel hub motor applied to an electric scooter, which comprises a stator and a rotor arranged around the stator, the stator is provided with a yoke part, a plurality of tooth parts arranged on the yoke part, a plurality of shoe parts arranged at one ends of the tooth parts and a plurality of coils wound on the tooth parts; the rotor is provided with a plurality of radial magnets and a plurality of circumferential magnets which are arranged in a Halbach array, the radial magnets and the circumferential magnets are arranged in a staggered mode, and the magnetic line direction of the radial magnets and the magnetic line direction of the circumferential magnets are perpendicular to each other. The hub motor in a Halbach array arrangement mode can be arranged in a wheel set of the electric scooter, and has good torque and efficiency.

Description

Technical Field

[0001] The utility model relates to a hub motor structure, in particular to a hub motor that can be applied to the wheel set of an electric scooter. The magnets of the rotor are arranged through a Halbach array, so that the hub motor has a smaller volume and maintains a high torque output. When assembled in the wheel set of an electric scooter, the overall weight of the hub motor can be reduced. Background Art

[0002] With the progress of technology, many things in life have been electrified, and the demand for motors has increased day by day. The principle of a motor is to convert electrical energy into kinetic energy to drive other devices to operate. The main components of a motor structure are a stator and a rotor. Coils are wound on the stator. After being energized, electromagnetic induction is generated between the coils and the rotor, enabling the rotor to generate an induced electromotive force and form an induced current. At this time, the rotor starts to rotate, and power can be output to the device connected to the rear end for use.

[0003] When a motor is installed as an auxiliary power source in the wheel set of a vehicle such as an electric bicycle or an electric scooter, it can be used as a hub motor. According to the feedback of the user's operation, the rotor of the hub motor directly drives the wheel to rotate, enabling the vehicle to perform forward or backward movements. The rotor of the motor is generally arranged with N poles and S poles alternating, as Figure 1 shown. Through this arrangement method, a uniform magnetic field distribution can be obtained on both sides of the rotor. This method is also the most common rotor magnet arrangement method at present. However, the rotor composed of this arrangement method will have a relatively large volume. After being combined with the stator, the volume of the hub motor increases, which means that the vehicle needs to use a larger wheel set to accommodate the hub motor. This not only directly increases the cost of the vehicle's wheel set but also increases the weight of the hub motor, failing to achieve the effect of light weight.

[0004] Patent Publication No. I838852 "Lightweight Motor Rotor Structure" discloses a lightweight structure of a motor rotor. The specification has explained that the lightweight of the motor rotor can reduce the load during high-speed rotation of the rotor and at the same time reduce the energy consumption during operation to achieve the purpose of saving operation costs. It can be seen that the weight of the motor rotor is quite important for the motor itself. Patent Publication No. I610518 "Electric Vehicle Including Hub Motor" discloses a hub motor that can be installed on a vehicle. It shows that the magnets of the rotor use rectangular permanent magnets and are configured to rotate around the stator. However, the rotor combination of this hub motor will occupy a relatively large volume, increasing the weight of the overall hub motor.

[0005] Therefore, how to provide a hub motor with a small volume and light weight, so that when it is installed on a vehicle, it can reduce the operation load of the motor and at the same time reduce the structural cost of the vehicle's wheel set, is the direction that the applicant is thinking about. Summary of the Invention

[0006] In view of the above-mentioned deficiencies still existing in the existing in-wheel motors during actual implementation, the applicant, by virtue of rich professional knowledge and years of practical experience, has made improvements and thus developed this utility model accordingly.

[0007] The main object of this utility model is to provide an in-wheel motor applied to an electric scooter, so that the rotor magnets can be arranged in a Halbach array, which can reduce the overall volume of the in-wheel motor without affecting the output torque, effectively reduce the material cost of the rotor, and can also reduce the overall vehicle weight of the electric scooter.

[0008] To achieve the above-mentioned implementation objectives, the in-wheel motor applied to the electric scooter of this utility model is arranged in a wheel set of an electric scooter. The in-wheel motor includes a stator, which includes a yoke portion, a plurality of tooth portions arranged on the yoke portion, a plurality of boot portions arranged at one ends of the plurality of tooth portions, and a plurality of coils wound around the plurality of tooth portions. A pair of symmetrical boot portions are arranged at one end of each tooth portion, and a slot opening is formed between the two boot portions of two adjacent tooth portions; and a rotor, arranged around the stator, includes a plurality of radial magnets arranged in a Halbach array and a plurality of circumferential magnets. The plurality of radial magnets are arranged staggered with the plurality of circumferential magnets, and the magnetic field line directions of the plurality of radial magnets are perpendicular to the magnetic field line directions of the plurality of circumferential magnets.

[0009] In an embodiment provided by this utility model, the wheel set of the electric scooter includes a wheel rim for accommodating the in-wheel motor, a fixed shaft connected to the stator, two bearings respectively sleeved at both ends of the fixed shaft, and a braking assembly arranged on the wheel rim.

[0010] In an embodiment provided by this utility model, the ratio of the size of each radial magnet to the sum of the sizes of each radial magnet and each circumferential magnet is 0.6 - 0.8.

[0011] In an embodiment provided by this utility model, the ratio of the size of the slot opening of the stator to the size of each circumferential magnet is 0.6 - 1.

[0012] In an embodiment provided by this utility model, the size refers to the length of each radial magnet and each circumferential magnet, and the width of the slot opening.

[0013] In an embodiment provided by this utility model, the magnetic field intensity of the plurality of radial magnets is higher than that of the plurality of circumferential magnets to reduce the demagnetization risk of the plurality of circumferential magnets.

[0014] In an embodiment provided by this utility model, the plurality of radial magnets can be selected from magnets with a magnet grade between N45 and N55.

[0015] In an embodiment provided by the present utility model, the plurality of circumferential magnets can be selected from magnets with a magnet grade between N35 and N42. Description of the Drawings

[0016] Through the following description of the embodiments of the present utility model with reference to the drawings, the above and other objects, features, and advantages of the present utility model will become clearer. In the drawings:

[0017] Figure 1 Schematic diagram of the arrangement of rotor magnets in the prior art;

[0018] Figure 2 Schematic diagram of the arrangement of rotor magnets in the preferred embodiment of the present utility model;

[0019] Figure 3 Partial cross-sectional view of the hub motor structure in the preferred embodiment of the present utility model;

[0020] Figure 4 Exploded view of the hub motor components in the preferred embodiment of the present utility model;

[0021] Figure 5 Schematic diagram of the volume comparison between the hub motor in the preferred embodiment of the present utility model and the prior art;

[0022] Figure 6 Graph of the relationship between the slot opening and the torque in the preferred embodiment of the present utility model;

[0023] Figure 7 Graph of the relationship between the slot opening and the torque ripple in the preferred embodiment of the present utility model;

[0024] Figure 8 Graph of the average torque of the relationship between the slot opening and the magnet ratio in the preferred embodiment of the present utility model;

[0025] Figure 9 Graph of the torque ripple of the relationship between the slot opening and the magnet ratio in the preferred embodiment of the present utility model;

[0026] Figure 10 Graph of the motor efficiency of the relationship between the slot opening and the magnet ratio in the preferred embodiment of the present utility model; and

[0027] Figure 11 Graph of the magnetic flux density of the thermal demagnetization comparison in the preferred embodiment of the present utility model.

[0028] In the above drawings, the specific meanings of the reference numerals are as follows:

[0029] 1. Motor;

[0030] 11. Stator;

[0031] 111. Yoke;

[0032] 112. Tooth part;

[0033] 113. Boot part;

[0034] 114. Coil;

[0035] 115. Slot opening;

[0036] 12. Rotor;

[0037] 121. Radial magnet;

[0038] 122. Circumferential magnet;

[0039] 123. Rotor seat;

[0040] 2. Wheel set;

[0041] 21. Rim;

[0042] 211. Side plate;

[0043] 22. Fixed shaft;

[0044] 23. Bearing;

[0045] 24. Braking assembly. Detailed implementation manners

[0046] In order to make the objectives, technical solutions and advantages of the present utility model clearer and more understandable, the following further elaborates on the present utility model in detail with reference to specific embodiments and the accompanying drawings.

[0047] The terms used herein are merely for describing specific embodiments and are not intended to limit the present utility model. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0048] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0049] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression. For example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc. In the case of using expressions such as "at least one of A, B, or C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression. For example, "a system having at least one of A, B, or C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.

[0050] It should also be noted that the directional terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only for reference to the drawings and are not used to limit the protection scope of the present invention. Throughout the drawings, the same elements are denoted by the same or similar reference numerals. When it may cause confusion in the understanding of the present invention, the conventional structures or configurations will be omitted.

[0051] Please refer to Figures 2 to 4 , a hub motor 1 applied to an electric scooter provided by an embodiment of the present invention is disposed in a wheel set 2 of an electric scooter. The wheel set 2 includes a rim 21 for accommodating the hub motor 1, a fixed shaft 22 connected to the stator 11, two bearings 23 respectively sleeved on both ends of the fixed shaft 22, and a braking assembly 24 disposed on the rim 21.

[0052] The hub motor 1 includes a stator 11 and a rotor 12. The stator 11 includes a yoke portion 111, a plurality of tooth portions 112 disposed on the yoke portion 111, a plurality of boot portions 113 disposed at one end of the plurality of tooth portions 112, and a plurality of coils 114 wound around the plurality of tooth portions 112. Two symmetrical boot portions 113 are disposed at one end of each tooth portion 112, and a slot opening 115 is formed between the two boot portions 113 of two adjacent tooth portions 112.

[0053] The rotor 12 is arranged around the stator 11 and includes a plurality of radial magnets 121 and a plurality of circumferential magnets 122 arranged in a Halbach array. The plurality of radial magnets 121 are arranged alternately with the plurality of circumferential magnets 122, and the magnetic field lines of the plurality of radial magnets 121 are perpendicular to the magnetic field lines of the plurality of circumferential magnets 122. The radial magnets 121 can be selected from magnets with a magnet grade between N45 and N55, and the circumferential magnets 122 can be selected from magnets with a magnet grade between N35 and N45. The magnetic field intensity of the radial magnets 121 will be higher than that of the circumferential magnets 122, reducing the demagnetization risk of the circumferential magnets 122. Among them, the ratio of the size of the radial magnets 121 to the sum of the sizes of the radial magnets 121 and the circumferential magnets 122 is 0.6 to 0.8, and the ratio of the size of the slot opening 115 of the stator 11 to the size of the circumferential magnets 122 is 0.6 to 1. The size here refers to the length of the radial magnets 121 and the circumferential magnets 122, and the width of the slot opening 115.

[0054] In addition, through the following specific embodiments, the practical application range of the present utility model can be further demonstrated, but the scope of the present utility model is not limited in any form.

[0055] Please continue to refer to Figures 2 to 4 , the hub motor 1 of the present utility model is used in the wheel set 2 of an electric scooter. The hub motor 1 is installed in the wheel rim 21 to directly drive the rotation of the wheel set 2, so that the electric scooter can perform forward or backward actions. In this embodiment, the stator 11 of the hub motor 1 is stacked by a plurality of silicon steel sheets to form a hollow annular yoke portion 111. The yoke portion 111 extends outward to form a plurality of tooth portions 112. Two symmetrical boot portions 113 are formed at one end of each tooth portion 112, and the position of the slot opening 115 can be defined between the boot portions 113 of adjacent tooth portions 112. The winding machine can wind the coil 114 on each tooth portion 112 through the slot opening 115.

[0056] The plurality of radial magnets 121 and the plurality of circumferential magnets 122 of the rotor 12 in this embodiment are arranged by a Halbach array. Among them, the magnetic field lines of the radial magnets 121 and the circumferential magnets 122 are perpendicular to each other, and the magnetic field lines are arranged in sequence of up, right, down, and left in a repeated manner. By this arrangement method, the effect of enhancing the magnetic field on a single side can be achieved, as Figure 2 shown. And this embodiment is an outer-rotor type hub motor 1 structure. The rotor 12 is arranged around the stator 11, and the side with a stronger magnetic field in the rotor 12 is adjacent to the stator 11, so that a large number of magnetic field lines are more likely to flow into the stator 11, and the torque will be increased, as Figure 3 shown.

[0057] Please also refer to Figure 4, the stator 11 and the rotor 12 are installed in the rim 21 of the wheel set 2 of the electric scooter to be used as the hub motor 1. The rotor 12 is arranged in the inner ring of the rim 21 through the rotor seat 123, and the fixed shaft 22 passes through the hollow area in the center of the stator 11. Two bearings 23 are respectively inserted at both ends of the fixed shaft 22, and the bearings 23 are fixed in the side plates 211 on both sides of the rim 21. Finally, the frame of the electric scooter is assembled with the fixed shaft 22, thus completing the combination of the electric scooter and the hub motor 1, enabling the hub motor 1 to directly drive the wheel set 2 to rotate. Then, the braking component 24 assembled on one of the side plates 211 of the rim 21 provides the braking function, allowing the electric scooter to decelerate in a timely manner.

[0058] Continuing to refer to Figure 5 , a comparison is made between the hub motor assembled with a surface-mounted magnet rotor of the prior art and the hub motor 1 of this embodiment using the Halbach array rotor 12. Since the existing magnet arrangement produces a uniform magnetic field distribution, when the existing stator cannot completely allow the magnetic lines of force to flow in, usually the overall size is increased to increase the stack height of the existing hub motor to accommodate more magnetic lines of force, so as to increase the torque of the existing hub motor; in this embodiment, with the magnet arrangement of the Halbach array, the characteristic is to enhance the magnetic field on one side. When used as the hub motor 1 of the electric scooter, there is no need to increase the stack height, and the same torque as the existing hub motor can be achieved with a smaller volume. As can be seen from the figure, the stack height of the existing hub motor is as high as 38 mm, while this embodiment is only 30.1 mm, with a volume difference of about 20%. However, during testing, the same torque of 8.35 Nm can be output. The hub motor 1 of the electric scooter of the present invention achieves the effect of weight reduction, with less use of overall iron and copper materials, having a very large advantage in terms of material cost and weight. Moreover, the hub motor 1 with a smaller volume can also provide more flexible choices for the wheel set 2.

[0059] In the prior art, in order to reduce the occurrence of magnetic leakage, currently for surface-mounted magnets (SPM), the width of the slot opening is usually required to be as narrow as possible, so that the magnetic lines of force can flow into the stator completely, enabling the magnetic flux density of the stator to reach a saturated state, and better torque characteristics can be obtained through a narrower slot opening. However, for the Halbach array rotor 12 used in the present invention, the applicant confirmed during the research process that this magnet arrangement is contrary to the surface-mounted magnet technology, and the slot opening 115 of the stator 11 is not the narrower the better. The slot opening 115 of the stator 11 has a curve relationship with the output torque. As Figure 6 shown, in this embodiment, when the width of the slot opening 115 is 2 mm and 8 mm, only a smaller torque can be obtained, while when the width of the slot opening 115 is about 5 mm, the maximum torque can be output. Continuing to refer to Figure 7, in the relationship between the slot opening 115 and the torque ripple, when the width of the slot opening 115 is 2 mm, the torque ripple presents the highest value. When the slot opening 115 gradually increases to 8 mm, the torque ripple will also decrease accordingly. It can be seen that when the width of the slot opening 115 is the smallest at 2 mm, both the torque output by the motor 1 and the torque ripple show poor data. In the figure, the trend of the torque ripple is relatively linear, and as the width of the slot opening 115 increases, the performance of the motor becomes more stable.

[0060] Based on the above research results, in order to standardize and obtain the best output data, the applicant defines that the dimensions of the radial magnet 121 and the circumferential magnet 122 of the rotor 12 have a specific proportional relationship, and there is also a matching of specific proportional relationships between the slot opening 115 of the stator 11 and the circumferential magnet 122 of the rotor 12, so that the output performance of the in-wheel motor 1 can stably fall within an optimal range and reduce the magnetic leakage phenomenon. In this embodiment, a relatively larger-sized magnet is selected for the radial magnet 121 relative to the circumferential magnet 122, that is, the length of the radial magnet 121 is greater than the length of the circumferential magnet 122. Affected by the circumferential magnet 122, the relationship between the radial magnet 121 and the circumferential magnet 122 can be defined by the ratio of the length of the radial magnet 121 to the sum of the lengths of the radial magnet 121 and the circumferential magnet 122 to define the embrace. This proportional relationship is shown in Formula (1). In this embodiment, a ratio of 0.6 to 0.8 for the embrace is a preferred ratio.

[0061] Embrace = Radial magnet / (Radial magnet + Circumferential magnet) Formula (1).

[0062] Please refer to again Figures 8 to 10 , in the figure, eb0.6, eb0.7, and eb0.8 represent that the embraces of this embodiment are 0.6, 0.7, and 0.8 respectively, and B type represents the existing in-wheel motor. From the relationship between the magnet ratio and the slot opening 115, it can be seen that when the slot opening 115 is 3 mm to 5 mm, the average torque and efficiency of the in-wheel motor 1 can be maintained within an optimal range, and the torque ripple presents relatively better data. The performance of the existing surface-mounted magnet motor structure B type is worse than that of this embodiment. And since most of the magnetic leakage phenomenon is generated by the circumferential magnet 122, based on the above embrace relationship, when adding the test, the width of the slot opening 115 can be determined according to the size (length) of the circumferential magnet 122. In this embodiment, the width of the slot opening 115 is set to 60% to 100% of the length of the circumferential magnet 122, which means the ratio of the width of the slot opening 115 to the length of the circumferential magnet 122 is 0.6 to 1. Thus, the rotor 12 made with the specific ratio of the radial magnet 121 and the circumferential magnet 122 and the specific ratio of the slot opening 115 and the circumferential magnet 122, when applied to the in-wheel motor 1, can effectively reduce magnetic leakage and achieve the best performance in terms of torque and efficiency.

[0063] During the operation of the in-wheel motor 1, its working temperature will inevitably rise gradually. In a high-temperature environment, there is a chance that the radial magnets 121 and circumferential magnets 122 of the rotor 12 will undergo thermal demagnetization, resulting in a decrease in the magnetic force of the radial magnets 121 and circumferential magnets 122. The thermal demagnetization of the magnets is an irreversible state. Once thermal demagnetization occurs, the output power of the in-wheel motor 1 will permanently decline, and the torque and efficiency will no longer be able to return to the data specifications before thermal demagnetization. If the thermal demagnetization phenomenon occurs repeatedly, the magnetic force of the radial magnets 121 and circumferential magnets 122 will gradually decrease in stages, resulting in a reduction in the torque of the in-wheel motor 1. In this embodiment, since the rotor 12 is arranged in a Halbach array, the radial magnets 121 and circumferential magnets 122 are arranged alternately, and the directions of the magnetic force lines are perpendicular to each other, which makes it easier for the circumferential magnets 122 to undergo thermal demagnetization. Therefore, when selecting the radial magnets 121 and circumferential magnets 122, the radial magnets 121 are selected with a larger magnet grade, such as N45, N48, N50, N52, N54 or N55, while the circumferential magnets 122 are selected with a smaller magnet grade, such as N35, N38, N40 or N42, which can effectively reduce the risk of thermal demagnetization of the circumferential magnets 122. In this embodiment, the radial magnets 121 and circumferential magnets 122 are made of neodymium iron boron material to obtain a larger magnetic force.

[0064] Generally speaking, the larger the magnet grade number, the larger the residual induction and maximum energy product, which means the stronger the magnetic field intensity. While for magnets with a smaller magnet grade number, although the magnetic field intensity is weaker, the coercive force is larger, indicating a better effect of resisting demagnetization.

[0065] The applicant compared three different combinations of magnet grades and conducted tests at a temperature of 120°C; for group (a), the radial magnets 121 were selected with a magnet grade of N50, and the circumferential magnets 122 were selected with a magnet grade of N35; for group (b), the radial magnets 121 were selected with a magnet grade of N50, and the circumferential magnets 122 were selected with a magnet grade of N40; for group (c), both the radial magnets 121 and circumferential magnets 122 were selected with a magnet grade of N50. Figure 11The flux density distributions of three groups of magnet grade combinations can be seen in [Figure], and the position circled by a circle in the figure shows the thermally demagnetized area on the circumferential magnet 122. The thermally demagnetized area of the magnet combination with the same magnet grade selected in group (c) is significantly larger than that in groups (a) and (b). If converted into actual values, the demagnetized area of group (a) is 0.987 mm2, the demagnetized area of group (b) is 1.187 mm2, and the demagnetized area of group (c) is 2.015 mm2. From this test result, it can be known that when the magnetic field intensity of the radial magnet 121 is higher than that of the circumferential magnet 122, the range of thermal demagnetization of the circumferential magnet 122 in a high-temperature environment can be effectively reduced, the influence on the output torque decay of the hub motor 1 can be reduced, the risk of thermal demagnetization can be controlled, and the service life of the hub motor 1 can be extended.

[0066] As can be seen from the above implementation description, compared with the prior art, the present utility model has the following advantages:

[0067] 1. For the hub motor applied to the electric scooter of the present utility model, the rotor magnets are arranged using the Halbach array, so that the magnetic force lines of the radial magnet and the circumferential magnet are in different directions, and the magnetic field will be concentrated on one side to increase the torque of the hub motor applied to the electric scooter, and the overall output power of the hub motor will also be improved.

[0068] 2. For the hub motor applied to the electric scooter of the present utility model, through the arrangement method of the Halbach array, while maintaining a high torque, the volume of the hub motor can be reduced, and the electric scooter can use a smaller wheel set to accommodate the hub motor of the present utility model. There are more flexible choices and applications on the wheel set, and the cost of the wheel set can also be reduced. The hub motor with a reduced volume can also save the overall material cost and reduce the weight, enabling the electric scooter to achieve a lightweight effect.

[0069] 3. For the hub motor applied to the electric scooter of the present utility model, the lengths of the radial magnet and the circumferential magnet of the rotor have a specific ratio, and the slot opening and the circumferential magnet also have a specific ratio. This dimensional relationship can reduce the magnetic leakage phenomenon, keep the magnetic flux density of the stator in a saturated state, and enable the hub motor to have high torque and high efficiency performance; by selecting a radial magnet with a magnetic field intensity higher than that of the circumferential magnet, the risk of thermal demagnetization of the circumferential magnet can be reduced, the situation of torque decay of the motor can be avoided, and the service life of the hub motor can be increased.

[0070] In summary, the hub motor of the present utility model applied to an electric scooter can indeed achieve the expected usage effect through the embodiments disclosed above. However, the schemas and descriptions disclosed above are only preferred embodiments of the present utility model. The methods and components disclosed in the above embodiments are only for illustrative purposes and are not used to limit the scope of the present utility model. Substitutions or variations of other equivalent components should also be covered by the scope of the patent application of the present utility model.

[0071] The embodiments of the present utility model have been described above. However, these embodiments are only for illustrative purposes and not for limiting the scope of the present utility model. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present utility model is defined by the appended claims and their equivalents. Without departing from the scope of the present utility model, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present utility model.

Claims

1. A hub motor for an electric scooter, arranged in a wheel set of an electric scooter, characterized in that: The wheel hub motor includes: A stator comprises a yoke, a plurality of teeth arranged on the yoke, a plurality of boots arranged at one end of the plurality of teeth, and a plurality of coils wound around the plurality of teeth, wherein one end of each of the teeth is provided with two symmetrical boots, and a slot opening is formed between the two boots of the two adjacent teeth; as well as A rotor is arranged around the stator, comprising a plurality of radial magnets and a plurality of circumferential magnets arranged in a Halbach array, wherein the plurality of radial magnets and the plurality of circumferential magnets are arranged alternately, and the directions of the magnetic lines of force of the plurality of radial magnets and the directions of the magnetic lines of force of the plurality of circumferential magnets are perpendicular to each other.

2. The hub motor for electric scooters according to claim 1, characterized in that: The wheel set of the electric scooter comprises a wheel rim for accommodating the wheel hub motor, a fixed shaft connected to the stator, two bearings respectively sleeved on both ends of the fixed shaft, and a brake assembly arranged on the wheel rim.

3. The hub motor for electric scooters according to claim 1, characterized in that: The ratio of the size of each radial magnet to the sum of the sizes of each radial magnet and each circumferential magnet is 0.6-0.

8.

4. The hub motor for electric scooters according to claim 1, characterized in that: The ratio of the size of the slot opening of the stator to the size of each of the circumferential magnets is 0.6-1.

5. The hub motor for electric scooters according to claim 3 or 4, characterized in that: The dimension refers to the length of each of the radial magnets and each of the circumferential magnets, and the width of the slot opening.

6. The hub motor for electric scooters according to claim 1, characterized in that: The magnetic field strength of the plurality of radial magnets is higher than the magnetic field strength of the plurality of circumferential magnets, so as to reduce the demagnetization risk of the plurality of circumferential magnets.

7. The hub motor for electric scooters according to claim 6, characterized in that: The plurality of radial magnets are magnets with a magnet grade between N45 and N55.

8. The hub motor for electric scooters according to claim 6, characterized in that: The plurality of circumferential magnets are magnets with grades ranging from N35 to N42.

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