A permanent magnet synchronous hub motor for electric vehicles and its application in electric vehicles

Abstract

This invention discloses a permanent magnet synchronous hub motor for electric vehicles and its application in electric vehicles. The motor includes a stator assembly integrated with the motor shaft and a permanent magnet outer rotor assembly integrated with the electric vehicle hub, magnetically coupled to the stator assembly, and coaxially outputting power. The stator assembly includes a stator core formed by stacking several stator laminations, each stator core having multiple winding slots containing stator windings. The permanent magnet outer rotor assembly includes a yoke ring and several permanent magnets fixedly spaced on the inner surface of the yoke ring, wherein the aspect ratio of the permanent magnets ranges from 0.18 to 0.2. This invention, through special design, achieves a lower permanent magnet thickness without negatively impacting the motor itself or its performance in electric vehicles.

Description

Technical Field

[0001] This invention belongs to the field of electric vehicles, and specifically relates to a permanent magnet synchronous hub motor for electric vehicles. This invention also relates to electric vehicles in which the permanent magnet synchronous hub motor is applied. Background Technology

[0002] In the field of electric vehicles, permanent magnet synchronous hub motors are commonly used as the driving power source for the wheel hubs. Permanent magnets are a crucial component of permanent magnet synchronous hub motors. The thickness (length) L in the magnetization direction and the equivalent radius R of the area perpendicular to the magnetization direction of the permanent magnet are generally referred to as the length-to-diameter ratio of the permanent magnet.

[0003] Extensive experimental research and analysis have verified that the aspect ratio of permanent magnet steel needs to meet certain values ​​to effectively avoid significant demagnetization problems in permanent magnet synchronous hub motors. However, setting the aspect ratio of permanent magnet steel too high not only fails to further improve the demagnetization problem of permanent magnet synchronous hub motors, but also requires a larger thickness of permanent magnet steel, which inevitably increases the material cost of permanent magnet steel. To achieve the best balance between avoiding demagnetization and cost, after extensive experimental screening, simulation software analysis, and summarization, the electric vehicle industry typically sets the aspect ratio of permanent magnet steel between 0.22 and 0.24, and the thickness L of permanent magnet steel is generally selected between 2.3 and 2.5 mm. This is common knowledge among engineers in the electric vehicle industry.

[0004] Currently, some technical solutions propose reducing the thickness of permanent magnet steel to attempt to lower material costs. For example, utility model patent CN206807248U discloses an electric vehicle hub motor with a stator core inner diameter of 214-234mm, an outer diameter of 250mm, an axial thickness of 18-23mm, and a permanent magnet thickness of 2-3mm. By increasing the outer and inner diameters of the stator core, the axial thickness of the stator core is reduced, thereby reducing the amount of copper wire winding and also reducing the thickness of the permanent magnet. This is illustrated in the patent's specification. As described in paragraph

[0006] , this technical solution unilaterally reduces the thickness of the copper wire winding and permanent magnet, which will of course cause a decrease in motor performance. However, due to the significant increase in the inner and outer diameters of the stator core, the weight is significantly reduced, thus compensating for the loss of motor performance. However, because this technical solution greatly increases the inner and outer diameters of the stator core, its compatibility with the wheel hub size in the prior art will be greatly limited, and the required wheel hub size will also increase significantly, resulting in an increase in wheel hub weight, which in turn brings new cost burdens and affects the working efficiency of the electric vehicle in the final application.

[0005] For example, the invention patent with publication number CN104753302A discloses a low-cost permanent magnet brushless DC motor for electric vehicles. By setting convex soft iron to make dummy poles, the amount of permanent magnet steel used is reduced. However, this motor actually sacrifices torque performance on the other hand.

[0006] Therefore, seeking an effective way to reduce the cost of permanent magnet steel without affecting the motor itself and its performance in electric vehicles is in line with the future green and efficient development direction of hub motors for electric vehicles, and is therefore very important and significant. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a permanent magnet synchronous hub motor for electric vehicles and an electric vehicle using the same, which, through special design, achieves that the motor itself and its related performance in electric vehicles will not be negatively affected by a lower thickness of permanent magnet steel.

[0008] The technical solution adopted in this invention is as follows: A permanent magnet synchronous hub motor for electric vehicles includes a stator assembly integrally connected to the motor shaft, and a permanent magnet outer rotor assembly integrally connected to the electric vehicle hub, magnetically coupled to the stator assembly, and coaxially outputting. The stator assembly includes a stator core formed by stacking a plurality of stator laminations, the stator core having a plurality of winding slots, and stator windings located in the winding slots; The permanent magnet outer rotor assembly includes a magnetic yoke ring and a plurality of permanent magnets fixedly spaced on the inner side of the magnetic yoke ring, wherein the aspect ratio of the permanent magnets ranges from 0.18 to 0.2.

[0009] Preferably, the thickness of the permanent magnet is in the range of 1.1-2 mm.

[0010] Preferably, the thickness of the permanent magnet is in the range of 1.2-2mm.

[0011] Preferably, the thickness of the permanent magnet is in the range of 1.5-1.9 mm.

[0012] Preferably, the permanent magnet is made of neodymium iron boron.

[0013] Preferably, the outer diameter of the stator core is in the range of 105-120mm, 145-180mm, 190-220mm, or 240-270mm; the number of winding slots is 36, 45, 48, 51, 54, 57, 63, or 72; and the number of permanent magnets is 40-80 pieces.

[0014] Preferably, the outer diameter of the stator core is 202-208 mm; the number of winding slots is 54; and the number of permanent magnets is 60.

[0015] Preferably, the permanent magnet synchronous hub motor includes a front cover and a rear cover that are rotatably mounted on both ends of the motor shaft via mounting bearings, and a Hall effect assembly for electrical connection with an electric vehicle controller. The stator core is fixedly connected to the motor shaft via a stator frame. The front cover and the rear cover are respectively fixed to the magnetic yoke ring with screws, and the magnetic yoke ring is integrated with the electric vehicle hub.

[0016] Preferably, an electric vehicle includes a permanent magnet synchronous hub motor, wherein the permanent magnet synchronous hub motor is a permanent magnet synchronous hub motor as described above.

[0017] Preferably, the electric vehicle is a two-wheeled, three-wheeled, or four-wheeled electric vehicle.

[0018] This invention, while maintaining the existing stator core structure, does not require increasing the outer diameter of the stator core, nor does it increase the size and weight of the electric vehicle wheel hub. Through multiple experimental analyses, it has been found that when neodymium iron boron (NdFeB) permanent magnets are used, by simply designing the aspect ratio of the permanent magnets within a specific range and significantly reducing the thickness of the permanent magnets, the performance of the permanent magnet synchronous hub motor can be guaranteed not to be negatively affected, fully meeting the relevant standards for electric vehicle motors. Therefore, the technical solution of this invention overcomes the limitations of simulation software in existing technologies and the long-standing technical biases of those skilled in the art. It can significantly reduce the amount of permanent magnet material used in existing commercially available permanent magnet synchronous hub motors, thereby significantly reducing the manufacturing cost of existing commercially available permanent magnet synchronous hub motors. Furthermore, since the technical solution of this invention only involves the special design of the permanent magnet dimensions, the solution is very simple and suitable for large-scale application, aligning with the future green and efficient development direction of hub motors for electric vehicles. Attached Figure Description

[0019] Appendix Figure 1 This is a schematic diagram of the permanent magnet synchronous hub motor according to a specific embodiment of the present invention; Appendix Figure 2 This is a schematic diagram of the stator assembly and permanent magnet external rotor assembly according to a specific embodiment of the present invention; Appendix Figure 3 It is attached Figure 2 Enlarged schematic diagram of the structure at point A in the middle; Appendix Figure 4 This is a schematic diagram of the stator assembly according to a specific embodiment of the present invention; Appendix Figure 5 This is a schematic diagram of the permanent magnet external rotor assembly according to a specific embodiment of the present invention; Appendix Figure 6This is a comparison chart of the motor performance parameter tests of Embodiment 1 and Comparative Example 1 of the present invention. Detailed Implementation

[0020] This invention discloses a permanent magnet synchronous hub motor for electric vehicles, including a stator assembly integrally connected to the motor shaft, and a permanent magnet outer rotor assembly integrally connected to the electric vehicle hub, magnetically coupled to the stator assembly, and coaxially outputting. The stator assembly includes a stator core formed by stacking a plurality of stator laminations, the stator core having multiple winding slots, and stator windings located in the winding slots. The permanent magnet outer rotor assembly includes a magnetic yoke ring and a plurality of permanent magnets fixedly spaced on the inner side of the magnetic yoke ring, wherein the aspect ratio of the permanent magnets ranges from 0.18 to 0.2.

[0021] This invention also discloses an electric vehicle, including a permanent magnet synchronous hub motor, wherein the permanent magnet synchronous hub motor is the permanent magnet synchronous hub motor described above.

[0022] This invention, while maintaining the existing stator core structure, does not require increasing the outer diameter of the stator core, nor does it increase the size and weight of the electric vehicle wheel hub. Through multiple experimental analyses, it has been found that when neodymium iron boron (NdFeB) is used for the permanent magnet, by simply designing the aspect ratio of the permanent magnet within a specific range and significantly reducing the thickness of the permanent magnet, the performance of the permanent magnet synchronous hub motor can be guaranteed not to be negatively affected, fully meeting the relevant standard requirements for electric vehicles. Therefore, the technical solution of this invention overcomes the limitations of simulation software in the prior art and the long-standing technical biases of those skilled in the art. It can significantly reduce the amount of permanent magnet material used in existing commercially available permanent magnet synchronous hub motors, thereby significantly reducing the manufacturing cost of existing commercially available permanent magnet synchronous hub motors. Furthermore, since the technical solution of this invention only involves specially designing the size and specifications of the permanent magnet, the solution is very simple, suitable for large-scale application, and conforms to the future green and efficient development direction of hub motors for electric vehicles. Example 1:

[0023] Please see Figure 1 The permanent magnet synchronous hub motor 100 shown includes a stator assembly 20 integrally connected to the motor shaft 10, a permanent magnet outer rotor assembly 40 integrally connected to the electric vehicle hub 30, magnetically coupled to the stator assembly 20, and coaxially outputting, a front end cover 50 and a rear end cover 60 rotatably mounted relative to each other at both ends of the motor shaft via mounting bearings, and a Hall effect component for electrical connection with the electric vehicle controller. Please refer to further details. Figure 2 , Figure 3 , Figure 4 and Figure 5As shown, the stator assembly 20 includes a stator core 21 formed by stacking a plurality of stator laminations. The stator core 21 has a plurality of winding slots 22, and stator windings are located in the winding slots 22. The permanent magnet outer rotor assembly 40 includes a magnetic yoke ring 41 and a plurality of permanent magnets 42 fixedly spaced on the inner side of the magnetic yoke ring 41. The stator core 21 is fixedly connected to the motor shaft 10 through the stator frame 23. The front end cover 50 and the rear end cover 60 are respectively fixed to the magnetic yoke ring with screws. The magnetic yoke ring 41 is connected to the electric vehicle wheel hub 30 as a whole. Preferably, the outer diameter of the stator core is in the range of 105-120mm, 145-180mm, 190-220mm, or 240-270mm; the number of winding slots is 36, 45, 48, 51, 54, 57, 63, or 72; and the number of permanent magnets is 40-80 pieces. In this embodiment of the invention, the selection of parameters such as the outer diameter of the stator core, the number of winding slots, and the number of permanent magnets can be set according to the specifications of motors in the prior art. These are not part of the technical content to be improved by this invention. Therefore, those skilled in the art can select the specific motor specifications within the above preferred range based on the actual needs of the existing market. These different specifications of motors can all implement the technical solution of this invention, and this invention does not particularly limit them.

[0024] Preferably, the permanent magnet 42 is made of neodymium iron boron; the outer diameter of the stator core 21 is in the range of 190-220mm, and the thickness of the permanent magnet 42 is in the range of 1.1-2mm; and the aspect ratio of the permanent magnet 42 is in the range of 0.18-0.2; preferably, the thickness of the permanent magnet 42 is in the range of 1.2-2mm, and even more preferably, the thickness of the permanent magnet 42 is in the range of 1.5-1.9mm.

[0025] Specifically, in this preferred embodiment, the outer diameter of the stator core 21 is 205.3 mm; the number of winding slots 22 is 54; the inner diameter of the magnetic yoke ring 41 is 210 mm; the number of permanent magnets 42 is 60, i.e., a 60-pole magnetic pole structure; the thickness of the permanent magnets 42 is 1.9 mm, the radius is 9.647, and the aspect ratio is 0.2. This embodiment also proposes an electric vehicle, including a permanent magnet synchronous hub motor, wherein the permanent magnet synchronous hub motor adopts the permanent magnet synchronous hub motor 100 as described above.

[0026] The electric vehicle in this embodiment of the invention can be a two-wheeled, three-wheeled, or four-wheeled electric vehicle. Specifically, in this embodiment, the electric vehicle is a two-wheeled electric vehicle. Of course, in other embodiments, the electric vehicle can be a three-wheeled or four-wheeled electric vehicle, and the technical effects to be achieved by this invention can also be obtained. Comparative Example 1:

[0027] The existing permanent magnet synchronous hub motor of the same specifications is adopted. The thickness of the permanent magnet is 2.3mm, the radius is 10.398, the length-to-diameter ratio is 0.22, and the other motor design parameters are basically the same.

[0028] Please see Figure 6 As shown, the applicant used motor performance testing software to analyze the motor performance of the above-mentioned Example 1 and Comparative Example 1 (mainly the torque-operating current curve and the torque-operating efficiency curve). It was found that Example 1 achieved essentially the same performance as Comparative Example 1, fully meeting the relevant performance standards requirements of electric vehicles for motors (including the requirement that the demagnetization rate should be less than 5%). Moreover, due to the effective reduction in the amount of permanent magnet steel used, the manufacturing cost of permanent magnet steel in Example 1 was reduced by at least 15% compared to Comparative Example 1. Example 2:

[0029] The remaining technical solutions of this embodiment 2 are the same as those of embodiment 1, except that: in this embodiment 2, the outer diameter of the stator core is 208mm; the number of winding slots is 54, the inner diameter of the magnetic yoke ring is 213mm; the number of permanent magnets is 60 pieces, that is, a 60-pole magnetic pole structure; the thickness of the permanent magnet is 1.6mm, the radius is 8.889mm, and the length-to-diameter ratio is 0.18. Example 3:

[0030] The remaining technical solutions of this embodiment 3 are the same as those of embodiment 1, except that: in this embodiment 3, the outer diameter of the stator core is 215mm; the number of winding slots is 54, the inner diameter of the magnetic yoke ring is 213mm; the number of permanent magnets is 60 pieces, that is, a 60-pole magnetic pole structure; the thickness of the permanent magnet is 1.5mm, the radius is 7.895mm, and the length-to-diameter ratio is 0.19. Example 4:

[0031] The remaining technical solutions of this embodiment 4 are the same as those of embodiment 1, except that: in this embodiment 4, the outer diameter of the stator core is 220mm; the number of winding slots is 54, the inner diameter of the magnetic yoke ring is 225.7mm; the number of permanent magnets is 60 pieces, that is, a 60-pole magnetic pole structure; the thickness of the permanent magnet is 1.7mm, the radius is 8.5mm, and the length-to-diameter ratio is 0.2.

[0032] Examples 2-4 can achieve essentially the same motor performance as Example 1, and the manufacturing cost of permanent magnets is reduced by at least 20% compared to Comparative Example 1. Example 5:

[0033] The remaining technical solutions of this embodiment 5 are the same as those of embodiment 1, except that: in this embodiment 5, the outer diameter of the stator core is 200mm; the number of winding slots is 54, the inner diameter of the magnetic yoke ring is 215.5mm; the number of permanent magnets is 60 pieces, that is, a 60-pole magnetic pole structure; the thickness of the permanent magnet is 1.4mm, the radius is 7.368mm, and the length-to-diameter ratio is 0.19. Example 6:

[0034] The remaining technical solutions of this embodiment 6 are the same as those of embodiment 1, except that: in this embodiment 6, the outer diameter of the stator core is 195.4 mm; the number of winding slots is 54, the inner diameter of the magnetic yoke ring is 200 mm; the number of permanent magnets is 60 pieces, that is, a 60-pole magnetic pole structure; the thickness of the permanent magnet is 1.3 mm, the radius is 7.222 mm, and the length-to-diameter ratio is 0.18. Example 7:

[0035] The remaining technical solutions of this embodiment 7 are the same as those of embodiment 1, except that: in this embodiment 7, the outer diameter of the stator core is 190mm; the number of winding slots is 54, the inner diameter of the magnetic yoke ring is 195mm; the number of permanent magnets is 60 pieces, that is, a 60-pole magnetic pole structure; the thickness of the permanent magnet is 1.2mm, the radius is 6mm, and the length-to-diameter ratio is 0.2.

[0036] Examples 5-7 achieved motor performance that was basically similar to that of Example 1. The motor efficiency was slightly lower than that of Example 1, but it still met the relevant performance standards for electric motors in electric vehicles. Moreover, the manufacturing cost of permanent magnet steel was reduced by at least 40% compared to Comparative Example 1. Example 8:

[0037] The remaining technical solutions of this embodiment 8 are the same as those of embodiment 1, except that: in this embodiment 8, the thickness of the permanent magnet is 1.1mm, the radius is 5.5mm, and the length-to-diameter ratio is 0.2.

[0038] The performance of the motor in Example 8 is significantly worse than that in Example 1, and it is also detrimental to the processing technology of permanent magnet steel. It is recommended not to further reduce the thickness of permanent magnet steel. Example 8 still meets the basic performance standards required for electric motors in electric vehicles, and the manufacturing cost of permanent magnet steel is reduced by at least 50% compared to Comparative Example 1. Example 9:

[0039] The remaining technical solutions of this embodiment 9 are the same as those of embodiment 1, except that: in this embodiment 9, the permanent magnet has a thickness of 2mm, a radius of 11.111mm, and an aspect ratio of 0.18.

[0040] This embodiment 9 can achieve basically the same motor performance as embodiment 1, and the manufacturing cost of the permanent magnet is reduced by about 12% compared to comparative example 1. However, it is recommended not to continue to increase the thickness of the permanent magnet, because the effect of reducing the cost of the permanent magnet is no longer significant. Comparative Example 2:

[0041] The remaining technical solutions of Comparative Example 2 are the same as those of Example 1, except that in Comparative Example 2, the permanent magnet has a thickness of 2 mm, a radius of 9.524 mm, and an aspect ratio of 0.21. Comparative Example 3:

[0042] The remaining technical solutions of Comparative Example 3 are the same as those of Example 1, except that: in Comparative Example 3, the thickness of the permanent magnet is 1.9 mm, the radius is 8.636 mm, and the aspect ratio is 0.22. Comparative Example 4:

[0043] The remaining technical solutions of Comparative Example 4 are the same as those of Example 1, except that in Comparative Example 4, the thickness of the permanent magnet is 1.8 mm, the radius is 7.5 mm, and the aspect ratio is 0.24. Comparative Example 5:

[0044] The remaining technical solutions of Comparative Example 5 are the same as those of Example 1, except that: in Comparative Example 5, the thickness of the permanent magnet is 1.5 mm, the radius is 6.818 mm, and the aspect ratio is 0.22. Comparative Example 6:

[0045] The remaining technical solutions of Comparative Example 6 are the same as those of Example 1, except that in Comparative Example 6, the thickness of the permanent magnet is 0.8 mm, the radius is 4 mm, and the aspect ratio is 0.2. Comparative Example 7:

[0046] The remaining technical solutions of Comparative Example 7 are the same as those of Example 1, except that in Comparative Example 7, the permanent magnet has a thickness of 1 mm, a radius of 5.556 mm, and an aspect ratio of 0.18. Comparative Example 8:

[0047] The remaining technical solutions of Comparative Example 8 are the same as those of Example 1, except that: in Comparative Example 8, the thickness of the permanent magnet is 1.9 mm, the radius is 11.176 mm, and the aspect ratio is 0.17.

[0048] The motor performance of Comparative Examples 2-8 was significantly worse than that of Example 1 (mainly due to a significantly higher demagnetization rate of more than 5%, which affected the efficiency and service life of the motor). They could not meet the relevant performance standards for electric motors in electric vehicles. Although the manufacturing cost of permanent magnets in these comparative examples was significantly lower than that of Comparative Example 1, they could not be applied in the electric vehicle industry. Comparative Example 9:

[0049] The remaining technical solutions of Comparative Example 9 are the same as those of Examples 1-9, except that the material of the permanent magnet in Comparative Example 9 is ferrite.

[0050] The motor performance of Comparative Example 9 is significantly worse than that of Example 1, and it cannot meet the relevant performance standards for electric motors in electric vehicles (mainly manifested in the motor demagnetization rate being significantly greater than 5% or the motor efficiency becoming significantly worse).

[0051] Those skilled in the art can apply the technical solutions of the above embodiments of the present invention to other permanent magnet synchronous hub motors for electric vehicles of different specifications in the prior art. For example, the outer diameter range of the stator core in the prior art is usually 105-120mm, 145-180mm, 190-220mm, or 240-270mm; the number of winding slots is 36, 45, 48, 51, 54, 57, 63, or 72; the number of permanent magnets is 40-80 pieces; more specifically, for example: a 54-slot 48-pole structure, or a 48-slot 42-pole structure, or a 48-slot 52-pole structure, or a 63-slot 56-pole structure, or a 36-slot 40-pole structure, or a 45-slot 50-pole structure, or a 51-slot 64-pole structure. The invention can utilize a 57-slot, 60-pole magnetic structure, a 72-slot, 80-pole magnetic structure, or any other number of winding slots plus a different number of magnetic poles found in existing technologies. Those skilled in the art can apply this core technical concept to permanent magnet synchronous hub motors for electric vehicles of various specifications without sacrificing other motor performance or structure. The resulting motor products, when combined and implemented, can achieve a level of technical improvement similar to that of embodiments 1-9 of this invention compared to existing motor products of the same specifications on the market. In other words, without sacrificing the motor performance required by electric vehicle industry standards, the thickness of the permanent magnet steel can be effectively reduced, thereby significantly reducing the manufacturing cost of the motor. Therefore, these combined applications are all considered within the scope of protection of this invention.

[0052] After comparing numerous embodiments and comparative examples of the present invention, remarkable technical effects were surprisingly discovered. Specifically, the embodiments of the present invention, while maintaining the existing stator core structure, do not require increasing the outer diameter of the stator core, nor the size and weight of the electric vehicle wheel hub, nor sacrifice other performance characteristics of the motor. Through multiple experimental analyses, it was found that when neodymium iron boron material is used for the permanent magnet, by simply designing the aspect ratio of the permanent magnet within a specific range (i.e., setting the aspect ratio range of the permanent magnet to 0.18-0.2), and significantly reducing the thickness of the permanent magnet, the performance of the permanent magnet synchronous hub motor can be guaranteed not to be negatively affected, fully meeting the relevant standard requirements for electric vehicles. Therefore, the present invention… The technical solution of the present invention overcomes the limitations of simulation software in the prior art and the long-standing technical biases of those skilled in the art. It can significantly reduce the amount of permanent magnet steel used in existing commercial permanent magnet synchronous hub motors (at least 10% reduction in permanent magnet steel cost; under optimized implementation, the cost of permanent magnet steel is only about 50-60% of that in the prior art, greatly saving the manufacturing cost of the motor). This significantly reduces the manufacturing cost of existing commercial permanent magnet synchronous hub motors. At the same time, since the technical solution of the present invention only involves special design of the size and specifications of the permanent magnet steel, the solution is very simple and suitable for large-scale application and implementation, which is in line with the green and efficient development direction of hub motors for electric vehicles in the future.

[0053] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0054] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0055] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A permanent magnet synchronous hub motor for electric vehicles, comprising a stator assembly integrally connected to the motor shaft, and a permanent magnet external rotor assembly integrally connected to the electric vehicle hub, magnetically coupled to the stator assembly, and coaxially outputting, characterized in that, The stator assembly includes a stator core formed by stacking a plurality of stator laminations, the stator core having a plurality of winding slots, and stator windings located in the winding slots; The permanent magnet outer rotor assembly includes a magnetic yoke ring and a plurality of permanent magnets fixedly spaced on the inner side of the magnetic yoke ring, wherein the permanent magnets are made of neodymium iron boron. When neodymium iron boron material is used for permanent magnet steel, by simply designing the aspect ratio of the permanent magnet steel within a specific range, and by significantly reducing the thickness of the permanent magnet steel, it can be ensured that the performance of the permanent magnet synchronous hub motor will not be negatively affected. The aspect ratio of the permanent magnet is in the range of 0.18-0.2; The thickness of the permanent magnet steel ranges from 1.5 to 1.9 mm.

2. The permanent magnet synchronous hub motor for electric vehicles as described in claim 1, characterized in that, The outer diameter of the stator core is in the range of 105-120mm, 145-180mm, 190-220mm, or 240-270mm; the number of winding slots is 36, 45, 48, 51, 54, 57, 63, or 72; and the number of permanent magnets is 40-80 pieces.

3. The permanent magnet synchronous hub motor for electric vehicles as described in claim 2, characterized in that, The outer diameter of the stator core is 202-208mm; the number of winding slots is 54; and the number of permanent magnets is 60.

4. The permanent magnet synchronous hub motor for electric vehicles as described in claim 1, characterized in that, The permanent magnet synchronous hub motor includes a front cover and a rear cover that are rotatably mounted on both ends of the motor shaft via bearings, and a Hall effect assembly for electrical connection with an electric vehicle controller. The stator core is fixedly connected to the motor shaft via a stator frame. The front cover and the rear cover are respectively fixed to the magnetic yoke ring with screws, and the magnetic yoke ring is integrated with the electric vehicle hub.

5. An electric vehicle, comprising a permanent magnet synchronous hub motor, characterized in that, The permanent magnet synchronous hub motor is the permanent magnet synchronous hub motor as described in any one of claims 1-4.

6. The electric vehicle as described in claim 5, characterized in that, The electric vehicle is a two-wheeled, three-wheeled, or four-wheeled electric vehicle.

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