Motor structure with high torque

Abstract

The utility model provides a motor structure with high torque, 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, one end of each tooth part is provided with two symmetrical shoe parts, and the other end of each tooth part is provided with a plurality of coils wound on the coil. A groove opening is formed between the two shoe parts of the adjacent 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, the size of the radial magnets and the size of the circumferential magnets have a specific proportion, and the size of the groove openings and the size of the radial magnets also have a specific proportion. Through the size relation of a specific proportion, the motor can effectively reduce magnetic flux leakage and achieve high-torque output.

Description

Technical Field

[0001] The utility model relates to a motor structure, and in particular to a motor structure capable of outputting high torque. The rotor magnets are arranged in a Halbach array to enhance the torque of the motor. The radial magnets and circumferential magnets of the rotor have a specific ratio in size, and the slot openings of the stator and the radial magnets of the rotor also have a specific ratio in size. The magnet size and the slot opening size are selected by the specific ratio, so that the magnetic leakage of the rotor is reduced and the torque of the motor is improved. Background Art

[0002] With the advancement of technology, many things in life have been electronicized, and the demand for motors is increasing. The principle of motors is to convert electrical energy into kinetic energy to drive other devices. The motor structure is mainly composed of a stator and a rotor. A coil is wound on the stator. When powered on, electromagnetic induction occurs between the coil and the rotor, allowing the rotor to generate an induced electromotive force and form an induced current. At this time, the rotor starts to rotate and can output power to the device connected to the back end.

[0003] The actual use of motors is often accompanied by efficiency loss. In terms of the materials used in motors, it can be divided into copper loss and iron loss. The occurrence of copper loss or iron loss can be improved through the design of winding or stator appearance. In addition, the leakage of the motor will also cause efficiency loss. The cause of leakage may be that the air gap between the stator and the rotor is too large, or the magnetic flux density of the stator design cannot fully accommodate the maximum magnetic force of the rotor, that is, the magnetic lines of force of the rotor magnet cannot completely flow into the stator, allowing the excess magnetic lines of force to flow outward. It may also be that the appearance design between the rotor and the stator prevents the magnetic lines of force of the rotor from flowing into the position of the stator. These phenomena that allow the magnetic lines of force of the rotor magnet to leak to areas outside the stator can be called leakage. The leakage of the motor will directly lead to a decrease in the output torque, and even the magnetic force leaking to the outside may further cause electromagnetic interference.

[0004] Patent announcement number M621912 "Rotor and motor" discloses a motor rotor structure for a compressor, which makes improvements on the position of the rotor magnet setting so that the gap between the magnets can satisfy a specific relationship to limit the path of the magnetic lines of force to achieve the purpose of reducing leakage flux; Patent announcement number M433018 "Permanent magnet synchronous motor that can reduce the cogging torque effect to improve motor efficiency" discloses a structure in which a depletion zone is additionally set at both ends of the rotor magnet slot. The depletion zone can prevent the formation of closed magnetic lines of force between the ends of the permanent magnets, so that the magnetic lines of force are forced to pass to the stator teeth. In this way, the magnetic lines of force can flow to the stator teeth more evenly to reduce leakage flux.

[0005] As can be seen from the previous patent, there are currently many technologies to improve the magnetic leakage phenomenon of motors, mainly through structural design to limit the path of magnetic lines of force so that the magnetic lines of force can flow completely into the stator; therefore, how to provide a motor that can effectively reduce magnetic loss and output high torque is the direction of the applicant's thinking. Utility Model Content

[0006] In view of the fact that the above-mentioned existing motor structure still has many deficiencies in actual implementation and use, the applicant has made improvements with the help of his rich professional knowledge and many years of practical experience, and has created the present utility model accordingly.

[0007] The main purpose of the utility model is to provide a motor structure with high torque. Through the specific proportional relationship between the sizes of the radial magnets and the circumferential magnets of the rotor, and the specific proportional relationship between the sizes of the stator slot openings and the radial magnets of the rotor, the leakage flux of the circumferential magnets of the rotor is reduced, so that the motor has high torque and high efficiency.

[0008] In order to achieve the above-mentioned implementation objectives, the motor structure with high torque of the utility model includes a stator, including 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, one end of each tooth is provided with two symmetrical boots, and a slot opening is formed between the two boots of two adjacent teeth; and a rotor, arranged around the stator, including a plurality of radial magnets and a plurality of circumferential magnets arranged in a Halbach array, the plurality of radial magnets are arranged alternately with the plurality of circumferential magnets, and 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, and the ratio of the size of the stator slot opening to the size of each radial magnet is 0.6~1

[0009] In an embodiment provided by the present invention, the size refers to the length of each radial magnet and each circumferential magnet, and the width of the slot opening.

[0010] In an embodiment provided by the present invention, directions of magnetic force lines of the plurality of radial magnets and directions of magnetic force lines of the plurality of circumferential magnets are perpendicular to each other.

[0011] In an embodiment provided by the present invention, the motor composed of the stator and the rotor can be further disposed in a wheel set of an electric scooter to be used as a hub motor.

[0012] In an embodiment provided by the present invention, the wheel set includes a wheel rim for accommodating a motor, a fixed shaft connected to a stator, two bearings respectively sleeved on both ends of the fixed shaft, and a brake set disposed on the wheel rim.

[0013] In an embodiment provided by the present invention, 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.

[0014] In an embodiment provided by the present invention, the plurality of radial magnets can be magnets with magnet grades ranging from N45 to N55.

[0015] In an embodiment provided by the present invention, the plurality of circumferential magnets can be magnets with magnet grades ranging from N35 to N45. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other purposes, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0017] Figure 1 A partial cross-sectional view of a motor structure according to a preferred embodiment of the utility model;

[0018] Figure 2 This is a schematic diagram of the arrangement of rotor magnets in a preferred embodiment of the utility model;

[0019] Figure 3 It is a schematic diagram of an exploded view of components of a motor applied to an electric scooter according to a preferred embodiment of the utility model;

[0020] Figure 4 A diagram showing the relationship between slot opening and torque of a preferred embodiment of the utility model;

[0021] Figure 5 A diagram showing the relationship between slot opening and torque ripple in a preferred embodiment of the utility model;

[0022] Figure 6 The average torque diagram of the slot opening and magnet ratio of the preferred embodiment of the utility model;

[0023] Figure 7 The torque ripple diagram of the slot opening and magnet ratio of the preferred embodiment of the utility model;

[0024] Figure 8 A motor efficiency diagram of the slot opening and magnet ratio of a preferred embodiment of the utility model;

[0025] Fig. 9 A schematic diagram of the arrangement of rotor magnets in the prior art;

[0026] Fig.10 A schematic diagram showing a volume comparison between a hub motor applied to an electric scooter according to a preferred embodiment of the present utility model and the prior art; and

[0027] Fig.11A magnetic flux density diagram showing a thermal demagnetization comparison of a preferred embodiment of the present invention.

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

[0029] 1. Motor;

[0030] 11. Stator;

[0031] 111. Yoke;

[0032] 112. Tooth;

[0033] 113. Boots;

[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. Wheel rim;

[0042] 211, side panels;

[0043] 22. Fixed axis;

[0044] 23. Bearings;

[0045] 24. Brake assembly. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0047] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "include", "comprises", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence 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] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

[0050] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only for reference to the drawings and are not intended to limit the scope of protection of the present invention. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted when they may cause confusion in the understanding of the present invention.

[0051] See also Figure 1~Figure 3 The present invention provides a motor 1 with high torque, including a stator 11 and a rotor 12, which can be arranged in a wheel set 2 of an electric scooter to be used as a hub motor. The wheel set 2 includes a wheel rim 21 for accommodating the 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 brake assembly 24 arranged on the wheel rim 21.

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

[0053] The rotor 12 is disposed around the stator 11 and includes a Halbach array. The plurality of radial magnets 121 and the plurality of circumferential magnets 122 are arranged in an array, the plurality of radial magnets 121 are arranged alternately with the plurality of circumferential magnets 122, the directions of the magnetic lines of force of the plurality of radial magnets 121 are perpendicular to the directions of the magnetic lines of force of the plurality of circumferential magnets 122, and the ratio of the size of the radial magnet 121 to the sum of the sizes of the radial magnet 121 and the circumferential magnet 122 is 0.6-0.8, and the ratio of the size of the slot opening 115 of the stator 11 to the size of the circumferential magnet 122 is 0.6-1, where the size refers to the length of the radial magnet 121 and the circumferential magnet 122, and the width of the slot opening 115; wherein the radial magnet 121 can be a magnet with a magnet grade of N45 to N55, and the circumferential magnet 122 can be a magnet with a magnet grade of N35 to N45, the magnetic field strength of the radial magnet 121 is higher than the magnetic field strength of the circumferential magnet 122, thereby reducing the demagnetization risk of the circumferential magnet 122.

[0054] In addition, the following specific embodiments can further demonstrate the practical application scope of the present invention, but do not limit the scope of the present invention in any form.

[0055] Please continue reading Figure 1 and Figure 2 In the embodiment of the utility model, the stator 11 of the motor 1 is formed by stacking a plurality of silicon steel sheets to form a hollow annular yoke 111. The yoke 111 extends outward to form a plurality of teeth 112. Two symmetrical boots 113 are formed at one end of each tooth 112. The position of a slot opening 115 can be defined between the boots 113 of adjacent teeth 112. The winding machine can wind the coil 114 on each tooth 112 through the slot opening 115.

[0056] The multiple radial magnets 121 and the multiple circumferential magnets 122 of the rotor 12 are arranged in a Halbach array, wherein the directions of the magnetic lines of force of the radial magnets 121 and the circumferential magnets 122 are perpendicular to each other, and the directions of the magnetic lines of force are repeatedly arranged in the order of top, right, bottom, and left. This arrangement can enhance the magnetic field on one side. In this embodiment, the motor 1 structure is an external rotation type, and the rotor 12 is arranged around the stator 11. The side of the rotor 12 with a stronger magnetic field is adjacent to the stator 11, so that a large amount of magnetic lines of force can flow into the stator 11 more easily, and the torque can be improved.

[0057] In the prior art, in order to reduce the occurrence of magnetic leakage, the current surface mounted magnetization (SPM) usually uses the narrower slot opening width as possible, so that the magnetic lines of force can flow into the stator completely, so that the magnetic flux density of the stator reaches a saturated state, and better torque characteristics are obtained through a narrower slot opening. However, for the rotor 12 using the Halbach array in the present invention, the applicant confirmed during the research process that this arrangement of magnets is opposite to the surface mounted magnetization technology, and the slot opening 115 of the stator 11 is not the narrower the better, and the slot opening 115 of the stator 11 will show a curve relationship with the output torque. Figure 4 As shown, in this embodiment, when the width of the slot opening 115 is 2 mm and 8 mm, only a small torque can be obtained, while when the width of the slot opening 115 is about 5 mm, the maximum torque can be output. Figure 5 In the relationship between the slot opening 115 and the torque ripple, when the slot opening 115 width is 2 mm, the torque ripple presents the highest value, and when the slot opening 115 gradually increases to 8 mm, the torque ripple also decreases accordingly. It can be seen that when the slot opening 115 width is the smallest 2 mm, the torque and torque ripple output by the motor 1 both present poor data. In the figure, the torque ripple trend is relatively linear, and as the slot opening 115 width increases, the motor performance becomes more stable.

[0058] Based on the above research results, in order to standardize and obtain the best output data, the applicant defines that the radial magnet 121 of the rotor 12 and the circumferential magnet 122 have a specific proportional relationship in size, and the slot opening 115 of the stator 11 and the circumferential magnet 122 of the rotor 12 also have a specific proportional relationship in size, so that the output performance of the motor 1 can stably fall within an optimal range and reduce the leakage magnetic phenomenon. In this embodiment, the radial magnet 121 is a magnet with a larger size than the circumferential magnet 122, that is, the length of the radial magnet 121 is greater than the length of the circumferential magnet 122. The relationship between the radial magnet 121 and the circumferential magnet 122 affected by 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. Please refer to formula (1) for this ratio. In this embodiment, the ratio of the magnetic circles is 0.6~0.8, which is a better ratio.

[0059] Magnetic circle (embrace) = radial magnet / (radial magnet + circumferential magnet) Formula (1).

[0060] Please see again Figure 6~Figure 8In the figure, eb0.6, eb0.7, and eb0.8 represent that the magnetic coils of this embodiment are 0.6, 0.7, and 0.8 respectively, and B type represents the existing motor structure. 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 motor 1 can be maintained in the optimal range, and the torque ripple presents relatively good data. The existing surface-mounted motor structure B type has a performance worse than that of the present embodiment, and since the magnetic flux leakage phenomenon is mostly caused by the circumferential magnet 122, based on the above-mentioned magnetic circle relationship, the width of the slot opening 115 is determined according to the size (length) of the circumferential magnet 122 during the test. In the present embodiment, the width of the slot opening 115 is set to 60% to 100% of the length of the circumferential magnet 122, which means that 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 manufactured with a specific ratio of the radial magnet 121 to the circumferential magnet 122 and a specific ratio of the slot opening 115 to the circumferential magnet 122 can effectively reduce magnetic flux leakage and achieve optimal torque and efficiency performance.

[0061] Furthermore, the stator 11 and the rotor 12 of the motor 1 of the utility model can be installed in the wheel rim 21 of the wheel set 2 of the electric scooter. The rotor 12 will be set on the inner ring of the wheel rim 21 through the rotor seat 123 to be used as a hub motor, and the fixed shaft 22 will be penetrated through the hollow area in the center of the stator 11. Two bearings 23 are respectively penetrated at both ends of the fixed shaft 22. The bearings 23 will be fixed in the side plates 211 on both sides of the wheel rim 21. Finally, the frame of the electric scooter is assembled with the fixed shaft 22 to complete the combination of the electric scooter and the motor 1, so that the motor 1 can directly drive the wheel set 2 to rotate, and then the brake assembly 24 assembled on one of the side plates 211 of the wheel rim 21 provides a braking function, so that the electric scooter can slow down in time.

[0062] Continue reading Fig. 9 and Fig.10 , a motor assembled by a rotor with a surface magnet in the prior art is compared with the motor 1 of the present embodiment using a rotor 12 with a Halbach array, Fig. 9 Schematic diagram of the magnet arrangement of the prior art. The existing rotor magnets are arranged with N poles and S poles alternately. Through this magnet arrangement, a uniform magnetic field distribution is generated on both sides. This is also the most common arrangement at present. When the existing stator cannot completely allow the magnetic lines of force to flow in, the overall size is usually increased to increase the thickness of the existing motor to accommodate more magnetic lines of force, so that the torque of the existing motor is improved. The present embodiment uses the magnet arrangement of the Halbach array, which is characterized by enhancing the magnetic field on one side, without increasing the thickness of the motor 1, and can achieve the same torque as the existing motor with a smaller volume. Fig.10It can be seen that the existing motor thickness is as high as 38 mm, while this embodiment is only 30.1 mm, which is about 20% different in volume. However, it can also output 8.35 Nm of torque during testing. In this way, when the motor 1 of the utility model is applied to other equipment, it can achieve a lightweight effect. The amount of iron and copper materials used in the motor 1 as a whole is less, which has a great advantage in material cost and weight. If it is used as a hub motor in an electric scooter, the smaller motor 1 can provide a more flexible choice for the wheel set 2.

[0063] During the use of the motor 1, the working temperature will inevitably rise gradually. In a high temperature environment, the radial magnets 121 and the circumferential magnets 122 of the rotor 12 may undergo thermal demagnetization, causing the magnetic force of the radial magnets 121 and the circumferential magnets 122 to decrease. The thermal demagnetization of magnets is an irreversible state. Once thermal demagnetization occurs, the output power of the motor 1 will permanently decline, and the torque and efficiency will not 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 the circumferential magnets 122 will gradually disappear, resulting in a decrease in the torque of the motor 1. In this embodiment, the magnetic force of the radial magnets 121 and the circumferential magnets 122 will gradually disappear, causing a decrease in the torque of the motor 1. In the embodiment, since the rotor 12 is arranged in a Halbach array, the radial magnets 121 and the circumferential magnets 122 are arranged alternately, and the directions of the magnetic lines of force are perpendicular to each other, which makes it easier for the circumferential magnets 122 to be thermally demagnetized. Therefore, when the radial magnets 121 and the circumferential magnets 122 are selected, the radial magnets 121 are selected with magnets of larger magnet grades, such as N45, N48, N50, N52, N54 or N55, and the circumferential magnets 122 are selected with magnets of smaller magnet grades, such as N35, N38, N40 or N42, which can effectively reduce the risk of thermal demagnetization of the circumferential magnets 122. In the present embodiment, the radial magnets 121 and the circumferential magnets 122 are made of neodymium iron boron to obtain a larger magnetic force.

[0064] Generally speaking, the larger the magnet brand number, the greater the residual induction and maximum energy product, which means the stronger the magnetic field strength. The smaller the magnet brand number, the weaker the magnetic field strength, but the greater the coercive force, which means it is better at resisting demagnetization.

[0065] Three groups of different magnet brand combinations were compared and tested at a temperature of 120°C; (a) the radial magnet 121 of group A uses magnet brand N50, and the circumferential magnet 122 uses magnet brand N35; (b) the radial magnet 121 of group B uses magnet brand N50, and the circumferential magnet 122 uses magnet brand N40; (c) the radial magnet 121 and the circumferential magnet 122 of group C both use magnet brand N50. Fig.11The magnetic flux density distribution of the three groups of magnet brand combinations can be seen in the figure. The circled position in the figure shows the thermal demagnetization area on the circumferential magnet 122. The thermal demagnetization area of ​​the magnet combination of group (c) using the same magnet brand is significantly larger than that of group (a) and group (b). If converted into actual values, the demagnetization area of ​​group (a) is 0.987 square millimeters, the demagnetization area of ​​group (b) is 1.187 square millimeters, and the demagnetization area of ​​group (c) is 2.015 square millimeters. Through this test result, it can be seen that when the magnetic field strength of the radial magnet 121 is higher than the magnetic field strength 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 decay of the output torque of the motor 1 can be reduced, the risk of thermal demagnetization can be controlled, and the service life of the motor 1 can be extended.

[0066] It can be seen from the above implementation description that compared with the prior art, the present invention has the following advantages:

[0067] 1. In the high-torque motor structure of the utility model, the lengths of the radial magnets and the circumferential magnets of the rotor have a specific proportional relationship, and the slot openings of the stator and the circumferential magnets of the rotor also have a specific proportional relationship. This size relationship can reduce the leakage magnetic phenomenon and maintain the magnetic flux density of the stator in a saturated state, so that the motor has high torque and high efficiency performance, thereby improving the motor output power.

[0068] 2. The high-torque motor structure of the utility model arranges the rotor magnets using the Halbach array so that the magnetic lines of force of the radial magnets and the circumferential magnets are in different directions, and the magnetic field is concentrated on one side to increase the torque of the motor, and the overall output power is also improved.

[0069] 3. The high-torque motor structure of the utility model can reduce the size of the motor while maintaining high torque through the arrangement of the Halbach array, and can also save the overall material cost and reduce the weight. When used as a hub motor, the wheel set of the electric scooter has more flexible selection and application, and can also reduce the cost of the wheel set, so that the electric scooter can achieve a lightweight effect; and by selecting radial magnets with a magnetic field strength higher than that of the circumferential magnets, the risk of thermal demagnetization of the circumferential magnets can be reduced, thereby avoiding the torque decay of the motor and increasing the service life of the motor.

[0070] In summary, the motor structure with high torque of the present invention can indeed achieve the expected use effect through the above-disclosed embodiments; however, the above-disclosed drawings and descriptions are only preferred embodiments of the present invention, and the methods and constituent elements disclosed in the above-disclosed embodiments are only for illustrative purposes and are not intended to limit the scope of the present invention. Replacements or changes of other equivalent elements should also be covered by the scope of the patent application of the present invention.

[0071] The embodiments of the present invention are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present invention is defined by the attached claims and their equivalents. Without departing from the scope of the present invention, a person skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A motor structure with high torque, characterized in that: Contains: 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 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, and the ratio of the size of the slot opening of the stator to the size of each radial magnet is 0.6-1.

2. The motor structure with high torque according to claim 1, 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.

3. The motor structure with high torque according to claim 1, characterized in that: The directions of the magnetic force lines of the plurality of radial magnets are perpendicular to the directions of the magnetic force lines of the plurality of circumferential magnets.

4. The motor structure with high torque according to claim 1, characterized in that: The motor composed of the stator and the rotor is further arranged in a wheel set of an electric scooter to be used as a hub motor.

5. The motor structure with high torque according to claim 4, characterized in that: The wheel set comprises a wheel rim for accommodating the motor, a fixed shaft connected to the stator, two bearings respectively sleeved on two ends of the fixed shaft and a brake assembly arranged on the wheel rim.

6. The motor structure with high torque 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 motor structure with high torque according to claim 6, characterized in that: The plurality of radial magnets are magnets with a magnet grade between N45 and N55.

8. The motor structure with high torque according to claim 6, characterized in that: The plurality of circumferential magnets are magnets with a magnet grade between N35 and N45.

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