An electric motor and electric device

Abstract

The application belongs to the technical field of electromagnetism and relates to a motor and an electric device, which comprise a stator and a rotor arranged oppositely; the stator comprises a stator yoke and a stator winding, and the rotor comprises a rotor yoke; the stator yoke and the rotor yoke are arranged oppositely and a gap exists between the opposite surfaces; a plurality of stator teeth are distributed on the surface of the stator yoke corresponding to the gap and are arranged at intervals in the circumferential direction; a stator slot is formed between two adjacent stator teeth; the stator winding is wound in the stator slot; a plurality of rotor teeth are arranged at intervals in the circumferential direction on the surface of the rotor yoke corresponding to the gap; a rotor slot is formed between two adjacent rotor teeth; and a first permanent magnet is arranged in the rotor slot; the motor satisfies the relationship formula: N s =k×n×m; N r =k×(n×m+2), so that the high-order harmonic magnetic fields generated by the rotor and the stator respectively generate torques, torque cancellation in the motor is reduced, the torque density of the motor is finally improved, the cost of the motor is reduced, and the torque fluctuation of the motor is greatly reduced.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic device technology, and more specifically, relates to an electric motor and an electric device. Background Technology

[0002] A direct drive motor is short for a direct-drive motor, which mainly refers to a motor that directly drives the load shaft to rotate without the need for a transmission device (such as a drive belt). Because direct drive motors have advantages such as quiet operation, energy saving, smooth operation, simple mechanical connection structure, and strong torque, they are suitable for various washing machine drive systems, electric bicycle drive systems, and electric motorcycle drive systems.

[0003] With the rapid development of society and technology, people have an increasing demand for direct drive motors that can output high torque density. However, existing direct drive motors still cannot meet people's needs in terms of torque density. Summary of the Invention

[0004] The purpose of this invention is to provide an electric motor and an electric device to solve the technical problem that existing direct drive motors still cannot meet people's needs in terms of torque density.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An electric motor is provided, comprising a stator and a rotor arranged opposite to each other; the stator includes a stator yoke and a stator winding, the rotor includes a rotor yoke and a first permanent magnet, the stator yoke and the rotor yoke are arranged opposite to each other with a gap between their opposite surfaces, the stator yoke has a plurality of stator teeth spaced apart along the circumferential direction on the surface corresponding to the gap, a stator slot is formed between two adjacent stator teeth, and the stator winding is wound within the stator slot;

[0006] The rotor yoke has a plurality of rotor teeth spaced apart along the circumferential direction on the surface corresponding to the gap, and a rotor slot is formed between two adjacent rotor teeth. The first permanent magnet is disposed in the rotor slot.

[0007] The motor satisfies the following relationship:

[0008] N s =k×n×m;

[0009] N r = k×(n×m+2);

[0010] Where, N s N represents the number of stator teeth. r denoted as the rotor pole number, k is a positive even number, n is a positive odd number greater than or equal to 3, and m is the number of phases of the stator winding and is a positive integer greater than or equal to 3.

[0011] In one embodiment, the radial height of the first permanent magnet is equal to the radial height of the rotor teeth; the rotor teeth are made of ferromagnetic material, or the rotor teeth are made of permanent magnet material, and the polarity of the magnetic field generated by the rotor teeth is opposite to the polarity of the magnetic field generated by the first permanent magnet.

[0012] In one embodiment, the rotor teeth are made of ferromagnetic material, and a second permanent magnet is provided on the surface of the rotor teeth corresponding to the gap. The magnetic field polarity generated by the second permanent magnet is opposite to that of the first permanent magnet, and the radial height of the first permanent magnet is equal to the sum of the radial height of the second permanent magnet and the radial height of the rotor teeth.

[0013] In one embodiment, the radial height of the second permanent magnet is equal to twice the radial height of the rotor teeth.

[0014] In one embodiment, N s Equals 36, N r It equals 44.

[0015] In one embodiment, a third permanent magnet is provided on one side of each stator slot near the gap; the magnetic field polarity generated by the third permanent magnet is the same as that generated by the first permanent magnet, or the magnetic field polarity generated by the third permanent magnet is the same as that generated by the second permanent magnet.

[0016] In one embodiment, the outer surface of the stator teeth facing the gap is a first curved surface. In the circumferential direction, the distance from a point on the first curved surface to the center of the circle gradually decreases from the middle to both ends of the first curved surface, and the radius difference at each point is between 0-5 mm; and / or,

[0017] The outer surface of the first permanent magnet facing the gap is a second curved surface. In the circumferential direction, the distance from a point on the second curved surface to the center of the circle gradually increases from the middle to both ends of the second curved surface, and the radius difference at each point is between 0-5 mm; and / or,

[0018] The outer surface of the second permanent magnet facing the gap is a third curved surface. In the circumferential direction, the distance from a point on the third curved surface to the center of the circle gradually increases from the middle to both ends of the third curved surface, and the radius difference at each point is between 0-5 mm; and / or,

[0019] The outer surface of the rotor teeth facing the gap is a fourth curved surface. In the circumferential direction, the distance from a point on the fourth curved surface to the center of the circle gradually increases from the middle of the fourth curved surface to both ends, and the radius difference at each point is between 0-5mm.

[0020] In one embodiment, the rotor further includes a rotor support, the rotor support including a chassis for mounting the rotor yoke, the central region of the stator yoke being an axially through hollow structure, a fan being fixed at the center of the chassis, and the fan being located in the hollow structure.

[0021] In one embodiment, the rotor support further includes an annular disk, on which a plurality of cooling fan blades are provided on the axial end face and / or outer side wall.

[0022] The present invention also provides an electric device, including the motor as described above.

[0023] The motor provided by this invention can bring the following beneficial effects: when the motor satisfies the relation N s =k×n×m and N r After k×(n×m+2), the number of stator teeth, rotor teeth, first permanent magnet and second permanent magnet can be reasonably configured so that the high-order harmonic magnetic fields generated by the rotor and stator can generate torque respectively, reducing torque cancellation in the motor, ultimately improving the torque density of the motor, reducing the cost of the motor, and greatly reducing the torque fluctuation of the motor. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A perspective view of the motor provided in an embodiment of the present invention;

[0026] Figure 2 This is a front view of the motor after the rotor support has been removed, as provided in an embodiment of the present invention.

[0027] Figure 3 A perspective view of the rotor support of the motor provided in an embodiment of the present invention;

[0028] Figure 4 A schematic diagram of the permanent magnet distribution in a motor provided in an embodiment of the present invention. Figure 1 ;

[0029] Figure 5 A schematic diagram of the permanent magnet distribution in a motor provided in an embodiment of the present invention. Figure 2 ;

[0030] Figure 6 A schematic diagram of the permanent magnet distribution in a motor provided in an embodiment of the present invention. Figure 3 ;

[0031] Figure 7 This is a torque fluctuation curve diagram of an existing motor.

[0032] Figure 8 The torque fluctuation curve of the motor provided in the embodiment of the present invention.

[0033] The following are the labeling elements in the figure:

[0034] 11-Stator yoke; 111-Stator tooth; 1111-First curved surface; 112-Stator slot; 113-Third permanent magnet; 12-Stator winding; 21-Rotor yoke; 211-Rotor tooth; 213-First permanent magnet; 214-Second permanent magnet; 22-Rotor support; 221-Chassis; 222-Annular disk; 223-First fan blade; 224-Second fan blade; 225-Third fan blade; 3-Gap; 4-Fan; 41-Main body; 42-Fan blade; 421-First part; 422-Second part. Detailed Implementation

[0035] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0036] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0037] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0038] Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," "third," or "fourth" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0039] Please see Figure 1 and Figure 5 The present invention will now describe the motor provided, which includes a stator and a rotor arranged opposite to each other. The stator includes a stator yoke 11 and a stator winding 12, and the rotor includes a rotor yoke 21 and a first permanent magnet 213. The stator yoke 11 and the rotor yoke 21 are arranged opposite to each other and there is a gap 3 between their opposite surfaces. A plurality of stator teeth 111 are distributed on the surface of the stator yoke 11 corresponding to the gap 3 and are spaced apart along the circumferential direction. A stator slot 112 is formed between two adjacent stator teeth 111, and the stator winding 12 is wound in the stator slot 112.

[0040] The gap 3 between the stator yoke 11 and the rotor yoke 21 forms an air gap, which allows for relative movement between the stator and rotor based on changes in the magnetic field generated by the stator winding 12. There can be one or more stators and rotors; that is, a rotor can be installed on one or both sides of a stator, or a stator can be installed on one or both sides of a rotor. When the motor includes multiple stators and / or multiple rotors, at least one stator and rotor adopts the structure of the stator and rotor in the embodiments of this application, while other stators or rotors can adopt the same or different structures as the stator or rotor in the embodiments of this application, depending on actual needs.

[0041] The rotor yoke 21 has multiple rotor teeth 211 spaced apart along the circumferential direction on the surface corresponding to the gap 3. A rotor slot is formed between two adjacent rotor teeth 211, and a first permanent magnet 213 is provided in the rotor slot.

[0042] The motor satisfies the following relationship:

[0043] N s = k × n × m; (Formula 1)

[0044] N r = k × (n × m + 2); (Formula 2)

[0045] Where, N s N represents the number of stator teeth 111. r denoted by , where is the number of rotor poles; k is a positive even number, i.e., k can be 2, 4, 6...; n is a positive odd number and greater than or equal to 3, i.e., n can be 3, 5, 7...; m is the number of phases of stator winding 12 and is a positive integer greater than or equal to 3, i.e., m can be 3, 4, 5... When m is greater than 3, if a phase of the motor is lost, the other phases can still make the motor work, thereby improving the fault tolerance capability of the motor in the event of a phase loss.

[0046] In this embodiment, the rotor pole number N rThe number of rotor poles N is equal to the sum of the number of rotor teeth 211 and the number of first permanent magnets 213. Since the first permanent magnets 213 are disposed in the rotor slots formed between two adjacent rotor teeth 211, the number of rotor teeth 211 and the number of first permanent magnets 213 are the same. That is to say, the number of rotor poles N is equal to the sum of the number of rotor teeth 211 and the number of first permanent magnets 213. r Twice the number of rotor slots.

[0047] Figure 7 The diagram shows the torque and torque fluctuation range of motors in the prior art, where the average torque of the competing motor is 19.6840 Nm and the torque fluctuation range is 5.5954 Nm; Figure 8 The figure shows the torque and torque fluctuation range of the present application after satisfying Formula 1 and Formula 2 above. The average torque value is 22.8333 Nm and the torque fluctuation range is 0.3630 Nm. It can be seen that the torque density of the motor of the present application is increased and the torque fluctuation is greatly reduced.

[0048] After satisfying Formula 1 and Formula 2 above, the number of stator teeth 111, rotor teeth 211 and first permanent magnet 213 can be reasonably configured so that the high-order harmonic magnetic fields generated by the rotor and stator can generate torque respectively, reducing torque cancellation in the motor, ultimately improving the torque density of the motor, reducing the cost of the motor, and greatly reducing the torque fluctuation of the motor.

[0049] In one embodiment, the radial height of the first permanent magnet 213 is equal to the radial height of the rotor teeth 211. For example... Figure 5 As shown, rotor teeth 211 are made of ferromagnetic material; or, as... Figure 6 As shown, the rotor teeth 211 are made of permanent magnet material, and the magnetic field polarity generated by the rotor teeth 211 is opposite to that generated by the first permanent magnet 213.

[0050] When the rotor teeth 211 are made of ferromagnetic material, since the rotor yoke 21 is also made of ferromagnetic material, the material of the rotor teeth 211 can be the same as that of the rotor yoke 21. For example, both the rotor yoke 21 and the rotor teeth 211 can be made of silicon steel sheets. In this case, the rotor yoke 21 and the rotor teeth 211 can be integrally formed or separately connected, depending on the actual needs. The material of the rotor teeth 211 can be the same as or different from that of the rotor yoke 21. For example, the rotor yoke 21 can be made of iron, and the rotor yoke 21 can be made of silicon steel sheets, depending on the actual needs. When the rotor teeth 211 are made of magnetically conductive material, the amount of permanent magnet material used can be reduced while slightly reducing the motor torque, thereby reducing the cost of the motor.

[0051] When the rotor teeth 211 are made of permanent magnet material, an additional magnetic field can be added, which is beneficial to increasing the torque of the motor and improving the performance of the motor.

[0052] It should be noted that the terms "radial" and "axial" in this application refer to the radial and axial directions of the subyoke 11, as well as the radial and axial directions of the rotor yoke 21.

[0053] When the rotor yoke 21 is made of silicon steel sheet, the rotor yoke 21 can be integrally formed or formed by stamping and stacking in sections. The specific setting can be selected according to actual needs.

[0054] In one embodiment, such as Figure 2 As shown, the rotor teeth 211 are made of ferromagnetic material; for example, they can be made of silicon steel sheets or iron, and the specific choice can be made according to actual needs. Figure 4 As shown, a second permanent magnet 214 is provided on the surface of the rotor tooth 211 corresponding to the gap 3. The magnetic field polarity generated by the second permanent magnet 214 is opposite to that of the first permanent magnet 213. The radial height of the first permanent magnet 213 is equal to the sum of the radial height of the second permanent magnet 214 and the radial height of the rotor tooth 211. In this way, a portion of the second permanent magnet 214 can be replaced by rotor teeth 211 made of the same material as the rotor yoke 21.

[0055] By setting a second permanent magnet 214 on the rotor teeth 211, on the one hand, the second permanent magnet 214 can increase the additional magnetic field, which is beneficial to improve the torque density or tension density of the motor; on the other hand, the second permanent magnet 214 with different radial heights can generate different magnetic reluctances. Therefore, the relationship between the motor torque, iron loss and power factor can be adjusted, the motor performance can be improved, the motor torque can be increased, and the application range of the motor can be expanded.

[0056] When the radial height of the second permanent magnet 214 approaches zero, such as Figure 5 As shown, at this point, the rotor teeth 211 gradually replace the second permanent magnet 214, and the radial height of the rotor teeth 211 becomes infinitely close to the radial height of the first permanent magnet 213. This reduces the amount of permanent magnet material used while slightly reducing the motor torque, thereby lowering the motor cost. When the radial height of the rotor teeth 211 becomes infinitely close to zero, the radial height of the second permanent magnet 214 becomes infinitely close to the radial height of the first permanent magnet 213, which increases the additional magnetic field, thus improving the motor torque and performance. In practical applications, the radial heights of the second permanent magnet 214 and the rotor teeth 211 can be adjusted according to actual needs.

[0057] Preferably, such as Figure 4As shown, the radial height of the second permanent magnet 214 is twice the radial height of the rotor teeth 211. At this time, the performance of the motor is almost unchanged from when the radial height of the second permanent magnet 214 is equal to the radial height of the first permanent magnet 213. However, it can improve the saturation density of the magnetic flux in the rotor yoke 21 between the first permanent magnet 213 and the second permanent magnet 214, save the amount of permanent magnet material used, and reduce the cost of the motor. At the same time, it can also serve as a mistake-proofing measure to facilitate the positioning of the first permanent magnet 213 and the second permanent magnet 214, prevent assembly personnel from assembling the first permanent magnet 213 and the second permanent magnet 214 incorrectly, improve the motor's pass rate, and reduce the motor's processing difficulty.

[0058] In one embodiment, N s Equals 36, N r The value is 44. This configuration, as verified by testing, improves motor efficiency, significantly reduces torque fluctuations, resulting in excellent energy savings. Furthermore, the motor operates with minimal vibration and is very quiet.

[0059] Since rotor slots are formed between two adjacent rotor teeth 211, the number of rotor slots is the same as the number of rotor teeth 211, meaning the number of first permanent magnets 213 is the same as the number of rotor teeth 211. When no second permanent magnet 214 is provided on the rotor teeth 211, the sum of the number of rotor teeth 211 and the number of first permanent magnets 213 is the rotor pole number N. r The number of rotor teeth 211 is 22, and the number of first permanent magnets 213 is also 22. When the rotor teeth 211 are made of permanent magnet material and the radial height of the rotor teeth 211 is equal to the radial height of the first permanent magnets 213, that is, the rotor teeth 211 completely replace the second permanent magnets 214, the sum of the number of first permanent magnets 213 and the number of rotor teeth 211 is the number of rotor poles N. r The number of first permanent magnets 213 is 22, and the number of rotor teeth 211 is also 22. When a second permanent magnet 214 is provided on the rotor teeth 211, and the radial heights of both the rotor teeth 211 and the second permanent magnet 214 are not zero, the sum of the number of rotor teeth 211 and the number of first permanent magnets 213, or the sum of the number of second permanent magnets 214 and the number of first permanent magnets 213, is the rotor pole number N. r .

[0060] In one embodiment, such as Figures 4 to 6As shown, a third permanent magnet 113 is provided on one side of each stator slot 112 near the air gap 3. The magnetic field polarity generated by the third permanent magnet 113 is the same as that generated by the first permanent magnet 213, or the magnetic field polarity generated by the third permanent magnet 113 is the same as that generated by the second permanent magnet 214. By providing the third permanent magnet 113 in the stator slot 112, the magnetic field strength of the air gap can be increased, which is beneficial to improving the torque density or tension density of the motor and increasing the torque of the motor.

[0061] Since the stator winding 12 generates heat when energized, if the third permanent magnet 113 is placed on the side of the stator slot 112 near the gap 3, and the third permanent magnet 113 is too close to the stator winding 12 wound in the stator slot 112, the third permanent magnet 113 will demagnetize under the magnetic field and high temperature environment, affecting the performance of the motor. Therefore, in practical applications, the third permanent magnet 113 should be kept away from the stator winding 12 as much as possible, and a reasonable distance should be set between the stator winding 12 and the third permanent magnet 113.

[0062] In practical applications, such as Figures 4 to 6 As shown, in the circumferential direction, the distance from the center of the circle to various points on the outer surface of the stator teeth 111 facing the gap 3 can be the same or different, and can be selected and set according to actual needs. In this embodiment, the outer surface of the stator teeth 111 facing the gap 3 is a first curved surface 1111. In the circumferential direction, the distance from a point on the first curved surface 1111 to the center of the circle gradually decreases from the middle to both ends of the first curved surface 1111, and the radius difference at each point is between 0-5mm. That is, the outer surface of the stator teeth 111 facing the gap 3 is modified. In this way, the magnetic field strength at both ends of the first curved surface 1111 is less than the magnetic field strength at the middle of the first curved surface 1111, increasing the gap 3 between the two ends of the first curved surface 1111 and the rotor yoke 21, reducing the sensitivity of the motor to changes in the magnetic field, thereby reducing the torque fluctuation of the motor.

[0063] In practical applications, the surfaces of the first permanent magnet 213 and / or the second permanent magnet 214 facing the gap 3 can be modified to reduce torque fluctuations in the motor. Specific settings can be selected according to actual needs. For example, in some embodiments, the outer surface of the first permanent magnet 213 facing the gap 3 is a second curved surface. In the circumferential direction, the distance from a point on the second curved surface to the center gradually increases from the middle to both ends of the second curved surface, and the radius difference at each point is between 0-5 mm. In some embodiments, the outer surface of the second permanent magnet 214 facing the gap 3 is a third curved surface. In the circumferential direction, the distance from a point on the third curved surface to the center gradually increases from the middle to both ends of the third curved surface, and the radius difference at each point is between 0-5 mm.

[0064] It is understandable that the surface of the rotor teeth 211 can be modified to reduce the torque fluctuation of the motor. For example, in some embodiments, the outer surface of the rotor teeth 211 facing the gap 3 is a fourth curved surface. In the circumferential direction, the distance from the point on the fourth curved surface to the center of the circle gradually increases from the middle of the fourth curved surface to both ends, and the radius difference at each point is between 0-5mm.

[0065] In one embodiment, such as Figure 1 and Figure 3 As shown, the rotor also includes a rotor support 22, which includes a chassis 221 for mounting the rotor yoke 21. The central area of ​​the stator yoke 11 is an axially through hollow structure. A fan 4 is fixed to the center of the chassis 221, and the fan 4 is located in the hollow structure. By fixing the fan 4 to the center of the chassis 221 of the rotor support 22, heat dissipation of the stator and rotor can be accelerated, motor losses can be reduced, motor efficiency can be improved, and the service life of the motor can be extended. In practical applications, in order to accelerate the heat dissipation of the motor, multiple axially through heat dissipation slots can be opened on the chassis 221, or the chassis 221 can be set as a hollow structure, which can be selected according to actual needs.

[0066] In one embodiment, such as Figure 3 As shown, the fan 4 includes a main body 41 and multiple fan blades 42. The main body 41 is fixed to the central area of ​​the chassis 221. Each fan blade 42 includes a first part 421 and a second part 422 disposed on the chassis 221. The first part 421 is spaced apart along the outer side wall of the main body 41 in a circumferential direction. The second part 422 extends from the first part 421 toward the direction away from the center of the chassis 221. The axial height of the second part 422 is less than the axial height of the first part 421. By extending the second part 422 from the first part 421 toward the direction away from the center of the chassis 221, the heat dissipation effect of the motor can be further improved. The second part 422 can be extended according to actual needs. For example, when there is an axial height difference between the stator yoke 11 and the chassis 221, the second part 422 can extend to the bottom of the stator winding 12, so that when the chassis 221 rotates with the rotor, the second part 422 can also accelerate the heat dissipation of the stator winding 12. It is understandable that, depending on the actual structure of the motor, additional protrusions can be added to the second part 422 to increase heat dissipation.

[0067] In one embodiment, such as Figure 1 and Figure 3 As shown, the rotor support 22 also includes an annular disk 222, and multiple heat dissipation fan blades are provided on the axial end face and / or outer side wall of the annular disk 222.

[0068] In one embodiment, the heat dissipation fan blades include first fan blades 223, and a plurality of first fan blades 223 are spaced apart along the circumferential direction on the chassis 221. The annular disk 222 is axially spaced from the chassis 221 and connected by a plurality of first fan blades 223. The inner wall of the annular disk 222 is provided with an annular groove, and the rotor yoke 21 is located in the annular groove.

[0069] Specifically, the rotor yoke 21 is located within the annular groove of the annular disk 222, which protects the rotor yoke 21. The annular disk 222 is axially spaced from the chassis 221 and connected by multiple first fan blades 223. Thus, when the rotor support 22 rotates, the annular disk 222, the chassis 221, and the multiple first fan blades 223 also rotate. The rotation of the multiple first fan blades 223 drives the airflow between the annular disk 222 and the chassis 221, accelerating the heat dissipation of the motor. At the same time, the axial spacing between the annular disk 222 and the chassis 221 further facilitates the heat dissipation of the motor.

[0070] In one embodiment, such as Figure 1 and Figure 3 As shown, the cooling fan also includes multiple second fan blades 224 spaced apart along the circumference, with the second fan blades 224 disposed on the end face of the annular disk 222 facing away from the first fan blade 223. Thus, when the rotor support 22 rotates, the multiple second fan blades 224 rotate together, driving the airflow on the side of the annular disk 222 facing away from the first fan blade 223, accelerating the heat dissipation of the motor.

[0071] In one embodiment, such as Figure 1 and Figure 3 As shown, the cooling fan also includes a plurality of third fan blades 225 that are spaced apart along the circumferential direction and protrude from the outer wall of the annular disk 222. Thus, when the rotor support 22 rotates, the plurality of third fan blades 225 rotate together, driving the airflow on the side of the annular disk 222 away from the center of the rotor yoke 21, thereby accelerating the cooling of the motor.

[0072] In one embodiment, the first fan blade 223, the second fan blade 224, and the third fan blade 225 are positioned correspondingly, and the two ends of the third fan blade 225 in the axial direction are respectively connected to the first fan blade 223 and the second fan blade 224. This facilitates the processing of the first fan blade 223, the second fan blade 224, and the third fan blade 225. Preferably, the first fan blade 223, the second fan blade 224, and the third fan blade 225 are integrally formed with the annular disk 222, simplifying the motor manufacturing process and reducing the difficulty of motor manufacturing.

[0073] The present invention also provides an electric device comprising the aforementioned motor. Specifically, the electric device can be an automated or semi-automated device. It should be noted that automated or semi-automated devices are applicable to various fields, such as industry, education, nursing, home appliances, or medical fields. In one embodiment, the electric device is a washing machine. In another embodiment, the electric device is an electric bicycle. In other embodiments, the electric device is an electric motorcycle.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electric machine characterized in that, The motor comprises oppositely arranged stator and rotor; the stator comprises stator yoke and stator winding, the rotor comprises rotor yoke and first permanent magnet, the stator yoke and the rotor yoke are oppositely arranged and there is a gap between the opposite surfaces, the surface of the stator yoke corresponding to the gap is provided with a plurality of stator teeth arranged at intervals in the circumferential direction, a stator slot is formed between adjacent two stator teeth, and the stator winding is arranged in the stator slot; The surface of the rotor yoke corresponding to the gap is provided with a plurality of rotor teeth arranged at intervals in the circumferential direction, a rotor slot is formed between adjacent two rotor teeth, and the first permanent magnet is arranged in the rotor slot; The motor satisfies the following relationship: N s = k x n x m; N r = k x (n x m + 2); where N s is the number of stator teeth, N r is the number of rotor poles, k is a positive even number, n is a positive odd number and is greater than or equal to 3, and m is the number of phases of the stator winding and is a positive integer greater than or equal to 3.

2. The electric machine of claim 1, wherein, The radial height of the first permanent magnet is equal to the radial height of the rotor tooth; the rotor tooth is a ferromagnetic material piece, or the rotor tooth is a permanent magnet material piece, and the polarity of the magnetic field generated by the rotor tooth is opposite to the polarity of the magnetic field generated by the first permanent magnet.

3. The electric machine of claim 1, wherein, The rotor tooth is a ferromagnetic material piece, the surface of the rotor tooth corresponding to the gap is provided with a second permanent magnet, the polarity of the magnetic field generated by the second permanent magnet is opposite to the polarity of the magnetic field generated by the first permanent magnet, and the radial height of the first permanent magnet is equal to the sum of the radial height of the second permanent magnet and the radial height of the rotor tooth.

4. The electric machine of claim 3, wherein, The radial height of the second permanent magnet is equal to twice the radial height of the rotor tooth.

5. The electric machine of any one of claims 1 to 4, wherein, N s equal to 36, N r equal to 44.

6. The electric machine of any one of claims 1 to 4, wherein, A third permanent magnet is arranged in each stator slot near the gap side; the polarity of the magnetic field generated by the third permanent magnet is the same as the polarity of the magnetic field generated by the first permanent magnet, or the polarity of the magnetic field generated by the third permanent magnet is the same as the polarity of the magnetic field generated by the second permanent magnet.

7. The electric machine of claim 3, wherein, The outer surface of the stator tooth facing the gap is a first curved surface, in the circumferential direction, the distance from the points on the first curved surface to the center gradually decreases from the middle to both ends of the first curved surface, and the radius difference at each place is between 0-5mm; and / or, The outer surface of the first permanent magnet facing the gap is a second curved surface, in the circumferential direction, the distance from the points on the second curved surface to the center gradually increases from the middle to both ends of the second curved surface, and the radius difference at each place is between 0-5mm; and / or, The outer surface of the second permanent magnet facing the gap is a third curved surface, in the circumferential direction, the distance from the points on the third curved surface to the center gradually increases from the middle to both ends of the third curved surface, and the radius difference at each place is between 0-5mm; and / or, The outer surface of the rotor tooth facing the gap is a fourth curved surface, in the circumferential direction, the distance from the points on the fourth curved surface to the center gradually increases from the middle to both ends of the fourth curved surface, and the radius difference at each place is between 0-5mm.

8. The electric machine of any one of claims 1 to 4, wherein, The rotor further comprises a rotor support, the rotor support comprises a bottom plate for mounting the rotor yoke, the central region of the stator yoke is a hollow structure axially through, the center of the bottom plate is fixed with a fan, and the fan is located in the hollow structure.

9. The electric machine of claim 8, wherein, The rotor support further comprises an annular disc, a plurality of heat dissipation fan blades are arranged on the axial end surface and / or the outer side wall of the annular disc.

10. An electrically powered device, characterized by The motor comprises the motor as claimed in any one of claims 1 to 9. The motor comprises the motor as claimed in any one of claims 1 to 9.

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