Stator assembly, motor and electrical equipment

Abstract

The invention discloses a stator assembly, a motor and electrical equipment, the stator assembly comprises a stator yoke part and a plurality of first stator teeth and a plurality of second stator teeth which are alternately arranged on the periphery of the stator yoke part at intervals along the circumferential direction, each first stator tooth comprises a first tooth part and a first tooth crest, and each second stator tooth comprises a second tooth part and a second tooth crest, the minimum tooth width W1 of the first tooth part, the minimum tooth surface width W2 of the first tooth crest, the minimum tooth width W3 of the second tooth part, the minimum tooth surface width W4 of the first tooth crest, the minimum distance L1 between two adjacent first tooth crests and the minimum distance L2 between the adjacent first tooth crest and second tooth crest meet the following conditions: (L1 / L2) * (W1 / W3) * (W2 / W4) is more than 10 and less than 40, W1 is more than W3, and W2 is more than W4; at least one side of the first tooth crest along the circumferential direction is provided with a first groove, and the notch of the first groove is opposite to the stator yoke part. According to the stator assembly provided by the invention, the back electromotive force of the motor can be maximized, and the performance of a torque current line curve is better, so that the output capability and efficiency of the motor are improved, and the cogging torque and the torque pulsation can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment, and in particular to a stator assembly, a motor and electrical equipment. Background Art

[0002] Permanent magnet motors (PMMs) have the advantages of simple structure, high power density, a wide high-efficiency range, and high torque density. They have become the mainstream motor type in the market and are widely used in modern industrial systems. The stator assembly of a PMM motor consists of a stator core and windings wound around the stator core. In related technologies, the winding operation is limited, requiring clearance for the winding nozzle. This results in a low slot fill rate for the stator assembly. In the presence of cogging torque, the output torque of the PMM motor deteriorates significantly, and operational smoothness decreases. Increasing the number of winding coils by increasing the winding slots results in a high degree of magnetic saturation in the stator core, preventing full utilization of the permanent magnet's magnetic field. This also affects the motor's output torque, resulting in poor output capacity and overload capability. Summary of the Invention

[0003] The present invention aims to address at least one of the technical problems existing in the prior art. To this end, the present invention provides a stator assembly that maximizes the back electromotive force of a motor and improves the accuracy of the torque-current curve, thereby increasing the motor's output capacity and efficiency while reducing cogging torque and torque ripple.

[0004] The present invention also provides a motor having the stator assembly and an electrical device having the motor.

[0005] According to an embodiment of the first aspect of the present invention, a stator assembly includes a stator yoke; a plurality of first stator teeth, the first stator teeth including a first tooth portion and a first tooth top, one end of the first tooth portion is connected to the stator yoke, the first tooth top is connected to the other end of the first tooth portion, along the circumference of the stator yoke, the first tooth portion has a first wall surface and a second wall surface that are opposite to each other, the minimum distance between the first wall surface and the second wall surface is W1, the first tooth top has a third wall surface and a fourth wall surface that are opposite to each other, the minimum distance between the end of the third wall surface that is opposite to the stator yoke and the end of the fourth wall surface that is opposite to the stator yoke is W2; a plurality of second stator teeth, the second stator teeth including a second tooth portion and a second tooth top, one end of the second tooth portion is connected to the stator yoke, the second tooth top is connected to the other end of the second tooth portion, along the circumference, the second tooth portion has a fifth wall surface that is opposite to each other wall and the sixth wall, the minimum distance between the fifth wall and the sixth wall is W3, the second tooth top has a seventh wall and an eighth wall facing away from each other, and the minimum distance between one end of the seventh wall facing away from the stator yoke and one end of the eighth wall facing away from the stator yoke is W4; wherein, a plurality of first stator teeth and a plurality of second stator teeth are alternately arranged on the outer periphery of the stator yoke along the circumferential direction, the minimum distance between two adjacent first tooth tops is L1, and the minimum distance between adjacent first tooth tops and second tooth tops is L2, satisfying: 10<(L1 / L2)*(W1 / W3)*(W2 / W4)<40, W1>W3, W2>W4; along the circumferential direction, the first tooth top protrudes toward both sides of the first tooth portion, and the first tooth top protrudes from at least one side of the first tooth portion and is provided with a first groove, and the notch of the first groove faces away from the stator yoke portion.

[0006] The stator assembly according to the embodiment of the first aspect of the present invention has at least the following beneficial effects: by limiting the value of (L1 / L2)*(W1 / W3)*(W2 / W4) to between 10 and 40, the structural size ratio of the first stator tooth and the second stator tooth can be optimized, so that the total receiving magnetic flux area of ​​the first stator tooth and the second stator tooth is maximized within a limited space, the total received magnetic flux is maximized, the copper loss is minimized, and the magnetic flux density in the iron core is made smaller to reduce iron loss, thereby maximizing the total magnetic flux linkage and total back electromotive force, and minimizing the magnetic circuit saturation of the first stator tooth and the second stator tooth, thereby optimizing the linearity of the motor torque current curve, thereby improving the overall output capacity of the motor, and improving the overall efficiency. At the same time, by arranging the first groove on the first tooth top with a larger width, on the one hand, it is convenient to process the first groove, and on the other hand, the first tooth top with a larger width can be approximately divided into multiple tooth tops, so that the distribution between the first groove and the tooth groove is more reasonable, so that during the rotation of the rotor assembly, the pulsation number of the tooth groove torque can be increased, thereby reducing the pulsation amplitude of the tooth groove torque, achieving the reduction of the tooth groove torque and the reduction of torque pulsation at the same time, which is beneficial to the smooth operation of the motor.

[0007] According to some embodiments of the present invention, the stator assembly further includes a winding, and the winding is wound around the first tooth portion.

[0008] According to some embodiments of the present invention, the second tooth portion is detachably connected to the stator yoke portion.

[0009] According to some embodiments of the present invention, the second tooth portion includes a mounting portion, the stator yoke is provided with a first mounting slot, the opening of the first mounting slot faces the second tooth top, and the mounting portion is accommodated in the first mounting slot.

[0010] According to some embodiments of the present invention, along the circumferential direction, the first mounting groove has a ninth wall surface and a tenth wall surface that are arranged opposite to each other, and in the radial direction perpendicular to the stator yoke portion, the distance between the ninth wall surface and the tenth wall surface is the width of the first mounting groove, and the first mounting groove includes a first slot section, which is located at one end of the first mounting groove close to the central axis of the stator yoke portion, and the width of the first slot section decreases from the stator yoke portion toward the second tooth top.

[0011] According to some embodiments of the present invention, the first mounting slot includes a second slot segment, the second slot segment is located at one end of the first slot segment close to the second tooth top, and the width of the second slot segment increases from the stator yoke toward the second tooth top.

[0012] According to some embodiments of the present invention, along the circumferential direction, the maximum width of the first installation groove is Y1, and the minimum width of the first installation groove is Y2, satisfying: 1<Y1 / Y2<3.

[0013] According to some embodiments of the present invention, along the radial direction of the stator yoke, the stator yoke has an eleventh wall and a twelfth wall facing away from each other, the eleventh wall is closer to the central axis of the stator yoke than the twelfth wall, the first mounting groove has a thirteenth wall facing away from the eleventh wall, the minimum distance between the eleventh wall and the twelfth wall is W5, and the minimum distance between the thirteenth wall and the eleventh wall is W6, satisfying: 0.2<(W5-W6) / W5<0.8.

[0014] The motor according to the second embodiment of the present invention includes the stator assembly and the rotor assembly according to the first embodiment of the present invention, wherein the rotor assembly is wound around the outer circumference of the stator assembly.

[0015] The motor according to the embodiment of the second aspect of the present invention has at least the following beneficial effects: by limiting the value of (L1 / L2)*(W1 / W3)*(W2 / W4) to between 10 and 40, the structural size ratio of the first stator tooth and the second stator tooth can be optimized, so that the total receiving magnetic flux area of ​​the first stator tooth and the second stator tooth is maximized within a limited space, the total received magnetic flux is maximized, the copper loss is minimized, and the magnetic flux density in the iron core is smaller to reduce iron loss, thereby maximizing the total magnetic flux linkage and total back electromotive force, and minimizing the magnetic circuit saturation of the first stator tooth and the second stator tooth, thereby optimizing the linearity of the motor torque current curve, thereby improving the overall output capacity of the motor, and improving the overall efficiency. At the same time, by arranging the first groove on the first tooth top with a larger width, on the one hand, it is convenient to process the first groove, and on the other hand, the first tooth top with a larger width can be approximately divided into multiple tooth tops, so that the distribution between the first groove and the tooth groove is more reasonable, so that during the rotation of the rotor assembly, the pulsation number of the tooth groove torque can be increased, thereby reducing the pulsation amplitude of the tooth groove torque, achieving the reduction of the tooth groove torque and the reduction of torque pulsation at the same time, which is beneficial to the smooth operation of the motor.

[0016] According to some embodiments of the present invention, the maximum outer diameter of the rotor assembly is D1, and the minimum inner diameter of the rotor assembly is D2, satisfying: 0.8<(W1 / W3)*(D2 / D1)<1.9.

[0017] According to some embodiments of the present invention, the maximum outer diameter of the rotor assembly is D1, and the minimum inner diameter of the rotor assembly is D2, satisfying: 1.4<(W2 / W4)*(D2 / D1)<3.2.

[0018] According to some embodiments of the present invention, the rotor assembly rotates forwardly along a first direction, and the first groove is located at a rear end of the first stator tooth along the first direction.

[0019] According to some embodiments of the present invention, the side of the first tooth top facing away from the first tooth portion has a fourteenth wall surface and a fifteenth wall surface, the fourteenth wall surface and the fifteenth wall surface are arranged sequentially along the first direction and are respectively located on both sides of the first groove, and the minimum distance between the two ends of the fifteenth wall surface along the circumferential direction is W7; the rotor assembly includes a rotor yoke and a plurality of first permanent magnets, the plurality of first permanent magnets are arranged on the inner circumference of the rotor yoke and are arranged at intervals along the circumferential direction, the maximum distance between the two walls of the first permanent magnets facing away from each other along the circumferential direction is W8, the maximum outer diameter of the rotor assembly is D1, and the minimum inner diameter of the rotor assembly is D2, satisfying: 0.6<(W7 / W8)*(D2 / D1)<1.11.

[0020] According to some embodiments of the present invention, along the circumferential direction, the minimum distance between the first grooves at the notch is W9, and the minimum distance between the two opposite walls of two adjacent first permanent magnets is W 10 , satisfying: 0.5<W9 / W 10 <2.

[0021] According to some embodiments of the present invention, the first tooth top is provided with the first groove on one side, and the first tooth top is also provided with a second groove, the second groove is located on the other side of the first tooth portion, and the notch of the second groove faces the rotor assembly.

[0022] According to some embodiments of the present invention, the first stator tooth has a symmetry center line arranged along the radial direction of the stator yoke, and the second groove and the first groove are arranged symmetrically with respect to the symmetry center line.

[0023] An electrical device according to an embodiment of the third aspect of the present invention includes the motor according to the embodiment of the second aspect of the present invention.

[0024] The electrical equipment according to the embodiment of the third aspect of the present invention has at least the following beneficial effects: by limiting the value of (L1 / L2)*(W1 / W3)*(W2 / W4) to between 10 and 40, the structural size ratio of the first stator tooth and the second stator tooth can be optimized, so that the total receiving magnetic flux area of ​​the first stator tooth and the second stator tooth is maximized within a limited space, the total received magnetic flux is maximized, the copper loss is minimized, and the magnetic flux density in the iron core is smaller to reduce iron loss, thereby maximizing the total magnetic flux linkage and total back electromotive force, and minimizing the magnetic circuit saturation of the first stator tooth and the second stator tooth, thereby optimizing the linearity of the motor torque current curve, thereby improving the overall output capacity of the motor, and improving the overall efficiency. At the same time, by arranging the first groove on the first tooth top with a larger width, on the one hand, it is convenient to process the first groove, and on the other hand, the first tooth top with a larger width can be approximately divided into multiple tooth tops, so that the distribution between the first groove and the tooth groove is more reasonable, so that during the rotation of the rotor assembly, the pulsation number of the tooth groove torque can be increased, thereby reducing the pulsation amplitude of the tooth groove torque, achieving the reduction of the tooth groove torque and the reduction of torque pulsation at the same time, which is beneficial to the smooth operation of the motor.

[0025] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0027] Figure 1 is a cross-sectional view of a motor in one embodiment of the present invention;

[0028] Figure 2 is a cross-sectional view of a stator assembly according to an embodiment of the present invention;

[0029] Figure 3 is a partial cross-sectional view of a stator assembly in one embodiment of the present invention;

[0030] Figure 4 is a partial cross-sectional view of the stator assembly and winding in an embodiment of the present invention;

[0031] Figure 5 is a cross-sectional view of a second stator tooth in an embodiment of the present invention;

[0032] Figure 6 is a partial cross-sectional view of a stator yoke according to an embodiment of the present invention;

[0033] Figure 7 is a cross-sectional view of a rotor assembly in one embodiment of the present invention.

[0034] Figure 8 is a partial cross-sectional view of a stator assembly in another embodiment of the present invention;

[0035] Figure 9 is a graph showing how the torque ripple of the motor varies with the distance from the notch of the first groove to the symmetric centerline of the first stator tooth in an embodiment of the present invention;

[0036] Figure 10 yes Figure 1 A magnified view of point A in the figure;

[0037] Figure 11 is a cross-sectional view of a first permanent magnet according to an embodiment of the present invention;

[0038] Figure 12 is a partial cross-sectional view of a rotor yoke in an embodiment of the present invention;

[0039] Figure 13 is a schematic projection diagram of the twenty-third wall surface along the direction of the rotation axis according to the embodiment of the present invention;

[0040] Figure 14 1 is a torque variation curve diagram of the motor according to the embodiment of the present invention and the motor according to the prior art solution over a period of time;

[0041] Figure 15 is a schematic structural diagram of the cooperation between the first permanent magnet and the rotor yoke in another embodiment of the present invention;

[0042] Figure 16 is a cross-sectional view of a rotor assembly in one embodiment of the present invention;

[0043] Figure 17 yes Figure 16 A cross-sectional view of the rotor yoke in FIG.

[0044] Figure 18 is a cross-sectional view of a second permanent magnet in one embodiment of the present invention;

[0045] Figure 19 is a cross-sectional view of a third permanent magnet in an embodiment of the present invention;

[0046] Figure 20 is a cross-sectional view of a fourth permanent magnet according to an embodiment of the present invention;

[0047] Figure 21 is a cross-sectional view of a rotor assembly in another embodiment of the present invention;

[0048] Figure 22 yes Figure 21 A cross-sectional view of the rotor yoke in FIG.

[0049] Figure 23 is a cross-sectional view of a motor in another embodiment of the present invention;

[0050] Figure 24is a cross-sectional view of a motor in another embodiment of the present invention;

[0051] Figure 25 is a cross-sectional view of a second permanent magnet in another embodiment of the present invention;

[0052] Figure 26 is a cross-sectional view of a second permanent magnet in another embodiment of the present invention.

[0053] Reference numerals:

[0054] stator yoke 100; first mounting slot 110; first slot section 111; second slot section 112; middle slot section 113; ninth wall surface 114; tenth wall surface 115; thirteenth wall surface 116; eleventh wall surface 120; twelfth wall surface 130;

[0055] First stator tooth 200; first tooth portion 210; first wall 211; second wall 212; first tooth top 220; third wall 221; fourth wall 222; first groove 223; eighteenth wall 2231; nineteenth wall 2232; fourteenth wall 224; fifteenth wall 225; second groove 226;

[0056] Second stator tooth 300; second tooth portion 310; fifth wall 311; sixth wall 312; mounting portion 313; second tooth top 320; seventh wall 321; eighth wall 322; and thirty-eighth wall 323;

[0057] Winding 400; tooth inserting space 410;

[0058] Rotor assembly 500; rotor yoke 510; recess 511; 20th wall 512; 21st wall 513; second mounting slot 514; third mounting slot 515; fourth mounting slot 516; first separator 517; 24th wall 5171; second separator 518; 25th wall 5181; first permanent magnet 520; 16th wall 521; 17th wall 522; 22nd wall 523; 23rd wall 524; second arc 525; straight Line segment 526; cutout 527; second permanent magnet 530; twenty-sixth wall surface 531; twenty-seventh wall surface 532; twenty-eighth wall surface 533; twenty-ninth wall surface 534; third permanent magnet 540; thirtieth wall surface 541; thirty-first wall surface 542; thirty-second wall surface 543; thirty-third wall surface 544; fourth permanent magnet 550; thirty-fourth wall surface 551; thirty-fifth wall surface 552; thirty-sixth wall surface 553; thirty-seventh wall surface 554; air gap 560;

[0059] First reference circle 600;

[0060] a second reference circle 700;

[0061] a third reference circle 800;

[0062] fourth reference circle 900;

[0063] Axis of rotation Z1; first straight line Z2; first reference point Q. DETAILED DESCRIPTION

[0064] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0065] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0066] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0067] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, assembling, and matching should be understood in a broad sense. Technical personnel in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0068] Permanent magnet motors (PMMs) have the advantages of simple structure, high power density, a wide high-efficiency range, and high torque density. They have become the mainstream motor type in the market and are widely used in modern industrial systems. The stator assembly of a PMM motor consists of a stator core and windings wound around the stator core. In related technologies, the winding operation is limited, and space must be reserved for the winding nozzle to exit. This results in a low slot fill rate for the stator assembly, which affects the output torque of the motor. Increasing the number of winding coils by increasing the winding slots will lead to a high degree of magnetic circuit saturation in the stator core, which will not fully utilize the magnetic field of the permanent magnets and will also affect the output torque of the motor. In other words, the motor's output capacity and overload capacity are poor. In addition, the permanent magnet motor has cogging torque, which can cause the permanent magnet motor to operate unstable and also affect its performance.

[0069] For this purpose, refer to Figures 1 to 26 As shown, a first embodiment of the present invention provides a stator assembly for use in a motor of an electrical device, where the electrical device may be a fan, an air-conditioning compressor, a refrigerator compressor, a drum washing machine, and the like.

[0070] Reference Figure 1 As shown, it can be understood that the motor is an external rotor motor. Specifically, the motor includes a stator assembly and a rotor assembly 500. The rotor assembly 500 is disposed around the outer circumference of the stator assembly and can rotate around the stator assembly. The rotation axis Z1 of the rotor assembly 500 coincides with the central axis of the rotor assembly 500 and the central axis of the stator assembly. Here, "external" refers to the side away from the rotation axis Z1, and the opposite side is "inner", that is, the side closer to the rotation axis Z1 is "inner".

[0071] Reference Figure 1 and Figure 2 As shown, it can be understood that the stator assembly includes a stator yoke 100, a plurality of first stator teeth 200, and a plurality of second stator teeth 300. The stator yoke 100 has a circular ring structure. The plurality of first stator teeth 200 and the plurality of second stator teeth 300 are both connected to the outer peripheral wall of the stator yoke 100. In addition, the plurality of first stator teeth 200 and the plurality of second stator teeth 300 are alternately arranged at equal intervals along the outer periphery of the stator yoke 100. In other words, the plurality of first stator teeth 200 and the plurality of second stator teeth 300 are arranged in a divergent manner on the outer periphery of the stator yoke 100, and the minimum distance between any adjacent first stator teeth 200 and second stator teeth 300 is equal. The number of first stator teeth 200 is equal to the number of second stator teeth 300. In this embodiment, the stator assembly includes six first stator teeth 200 and six second stator teeth 300.

[0072] Reference Figure 1 and Figure 7 As shown, it can be understood that the rotor assembly 500 includes a rotor yoke 510 and a plurality of first permanent magnets 520. The rotor yoke 510 has a circular ring structure. The plurality of first permanent magnets 520 are disposed on the inner circumferential wall of the rotor yoke 510 and are arranged at equal intervals along the circumference of the rotor yoke 510. In other words, the first permanent magnets 520 are located between the rotor yoke 510 and the first stator teeth 200 (or second stator teeth 300). The first permanent magnets 520 can be bonded to the rotor yoke 510 or positioned and mounted on the rotor yoke 510 via recesses 511. Air gaps 560 are formed between the first permanent magnets 520 and the first stator teeth 200, and between the first permanent magnets 520 and the second stator teeth 300. In this embodiment, the rotor assembly 500 includes ten first permanent magnets 520. The magnetic fields of any two adjacent first permanent magnets 520 are in opposite directions. In other words, the rotor assembly 500 includes five first permanent magnets 520 and five second permanent magnets 530.

[0073] Reference Figure 1 and Figure 2 As shown, it can be understood that the first stator tooth 200 includes a first tooth portion 210 and a first tooth top 220. One end of the first tooth portion 210 is connected to the outside of the stator yoke 100, and the other end of the first tooth portion 210 extends radially outward of the stator yoke 100. The first tooth top 220 is connected to the other end of the first tooth portion 210, that is, the first tooth top 220 is connected to the end of the first tooth portion 210 facing away from the stator yoke 100. Along the circumference of the stator yoke 100, the first tooth top 220 is protruding toward both sides of the first tooth portion 210, so that the two ends of the first tooth top 220 protrude from both sides of the first tooth portion 210, so that the first tooth top 220 can limit the wire when the first tooth portion 210 is wound.

[0074] Reference Figure 1 and Figure 2 As shown, it can be understood that the second stator tooth 300 includes a second tooth portion 310 and a second tooth top 320. One end of the second tooth portion 310 is connected to the outside of the stator yoke 100, and the other end of the second tooth portion 310 extends radially outward of the stator yoke 100. The second tooth top 320 is connected to the other end of the second tooth portion 310, that is, the second tooth top 320 is connected to the end of the second tooth portion 310 facing away from the stator yoke 100. Along the circumference of the stator yoke 100, the second tooth top 320 is arranged to protrude toward both sides of the second tooth portion 310, so that the two ends of the second tooth top 320 protrude from the two sides of the second tooth portion 310 respectively.

[0075] Reference Figure 2 As shown, it can be understood that along the circumference of the stator yoke 100, the second stator tooth 300 and the two adjacent first stator teeth 200 are arranged at intervals, so that a tooth groove is formed between the second tooth portion 310 and the two adjacent first tooth portions 210, and a tooth groove notch is formed between the second tooth top 320 and the two adjacent first tooth tops 220.

[0076] Reference Figure 2 As shown, it can be understood that the first tooth top 220 is provided with a first groove 223, and the first groove 223 is located on the side of the first tooth top 220 facing away from the stator yoke 100, and the notch of the first groove 223 faces the side facing away from the stator yoke 100, that is, the notch of the first groove 223 faces the rotor assembly 500. It is easy to understand that the first groove 223 can pass through the first tooth top 220 along the central axis of the stator yoke 100, or the first groove 223 extends along the central axis of the stator yoke 100 and is provided on a partial structure of the first tooth top 220.

[0077] Reference Figure 2As shown, it can be understood that the first groove 223 is located on the side of the first tooth top 220 protruding from the first tooth portion 210 , that is, the first groove 223 deviates from the middle position of the first tooth top 220 along the circumferential direction of the stator yoke 100 .

[0078] Reference Figure 2 As shown, it can be understood that the first stator tooth 200 has an axisymmetric structure, with the first stator tooth 200 having a centerline of symmetry arranged radially along the stator yoke 100. The first stator tooth 200 is symmetrically arranged about its own centerline of symmetry. It is easy to understand that the centerline of symmetry of the first stator tooth 200 is perpendicular to the central axis of the stator yoke 100. The first groove 223 can be arranged on either side of the centerline of symmetry of the first stator tooth 200 along the circumference of the stator yoke 100.

[0079] Therefore, by setting the first groove 223 on the first tooth top 220, the first groove 223 can be regarded as another structure of the tooth slot, which is equivalent to increasing the number of tooth slots of the stator assembly. During the rotation of the rotor assembly 500, the number of tooth slots can be increased to increase the pulsation number of the tooth slot torque, thereby reducing the pulsation amplitude of the tooth slot torque, thereby reducing the tooth slot torque and reducing the torque pulsation at the same time, which is beneficial to the smooth operation of the motor.

[0080] Furthermore, when used with the unilateral armature reaction of the stator assembly, the motor's torque ripple is greater under loaded conditions than under no-load conditions due to the unilateral armature reaction. Therefore, providing the first groove 223 on the first tooth top 220 can reduce torque ripple under loaded conditions, allowing the motor to operate smoothly even under loaded conditions.

[0081] Reference Figure 3 As shown, it can be understood that along the circumference of the stator yoke 100, the first tooth portion 210 has a first wall 211 and a second wall 212 that are separated from each other. The minimum distance between the first wall 211 and the second wall 212 is defined as W1. When measuring W1, the vernier caliper can be used to directly measure the position where the distance between the first wall 211 and the second wall 212 is the smallest. Generally speaking, the first wall 211 and the second wall 212 are parallel, and both the first wall 211 and the second wall 212 are parallel to the central axis of the stator yoke 100. The central axis of the stator yoke 100 is also the central axis of the stator assembly. The vertical distance between the first wall 211 and the second wall 212 is equal at all locations. Therefore, when measuring W1, the vertical distance between any location on the first wall 211 and the second wall 212 can be directly measured. The minimum distance W1 between the first wall 211 and the second wall 212 can be understood as the minimum tooth width of the first tooth portion 210.

[0082] Reference Figures 1 to 3As shown, it can be understood that when the rotor assembly 500 rotates counterclockwise, it is defined as positive rotation, and when the rotor assembly 500 rotates clockwise, it is defined as reverse rotation. The counterclockwise direction is defined as the first direction. The first groove 223 is located at the rear end of the first stator tooth 200 along the first direction. It is easy to understand that along the circumference of the stator yoke 100, the first groove 223 divides the wall surface (i.e., the tooth surface) on the side of the first tooth top 220 facing away from the stator yoke 100 into a fourteenth wall surface 224 and a fifteenth wall surface 225. The fourteenth wall surface 224 and the fifteenth wall surface 225 are respectively located on both sides of the first groove 223 along the circumference of the stator yoke 100, and the fourteenth wall surface 224 and the fifteenth wall surface 225 are arranged in sequence along the first direction. Along the circumference of the stator yoke 100, the distance between the two ends of the fourteenth wall surface 224 is smaller than the distance between the two ends of the fifteenth wall surface 225.

[0083] Reference Figure 3 As shown, it can be understood that, along the circumference of the stator yoke 100, the first tooth top 220 has a third wall surface 221 and a fourth wall surface 222 that are separated from each other, wherein the third wall surface 221 is defined as the wall surface closer to the fourteenth wall surface 224, and the fourth wall surface 222 is defined as the wall surface closer to the fifteenth wall surface 225. Along the circumference of the stator yoke 100, the minimum distance between the end of the third wall surface 221 facing away from the stator yoke 100 (i.e., the outer end) and the end of the fourth wall surface 222 facing away from the stator yoke 100 (i.e., the outer end) is defined as W2. In other words, W2 is the minimum distance between the intersection of the third wall surface 221 and the fourteenth wall surface 224 and the intersection of the fourth wall surface 222 and the fifteenth wall surface 225. When measuring W2, a vernier caliper can be used to measure the minimum distance between the intersection of the third wall 221 and the fourteenth wall 224 and the intersection of the fourth wall 222 and the fifteenth wall 225. Alternatively, on a projection plane perpendicular to the central axis of the stator yoke 100, the distance between the intersection of the projection of the third wall 221 and the fourteenth wall 224 and the intersection of the projection of the fourth wall 222 and the fifteenth wall 225 can be measured. The minimum distance W2 between the end of the third wall 221 facing away from the stator yoke 100 (i.e., the outer end) and the end of the fourth wall 222 facing away from the stator yoke 100 (i.e., the outer end) can be understood as the minimum tooth face width of the first tooth tip 220.

[0084] Reference Figure 3As shown, it can be understood that along the circumference of the stator yoke 100, the second tooth portion 310 has a fifth wall 311 and a sixth wall 312 that are separated from each other. The minimum distance between the fifth wall 311 and the sixth wall 312 is defined as W3. When measuring W3, the vernier caliper can be used to directly measure the position where the distance between the fifth wall 311 and the sixth wall 312 is the smallest. Generally speaking, the fifth wall 311 and the sixth wall 312 are parallel, and the fifth wall 311 and the sixth wall 312 are both parallel to the central axis of the stator yoke 100. The vertical distance between the fifth wall 311 and the sixth wall 312 is equal at all locations. Therefore, when measuring W3, the vertical distance between any location on the fifth wall 311 and the sixth wall 312 can be directly measured. The minimum distance W3 between the fifth wall 311 and the sixth wall 312 can be understood as the minimum tooth width of the second tooth portion 310.

[0085] Reference Figure 3 As shown, it can be understood that along the circumference of the stator yoke 100, the second tooth top 320 has a seventh wall surface 321 and an eighth wall surface 322 that are separated from each other. The minimum distance between the end of the seventh wall surface 321 that faces away from the stator yoke 100 (i.e., the outer end) and the end of the eighth wall surface 322 that faces away from the stator yoke 100 (i.e., the outer end) is defined as W4. The second tooth top 320 also has a thirty-eighth wall surface 323. The thirty-eighth wall surface 323 is located on the side of the second tooth top 320 that faces away from the stator yoke 100. The two ends of the thirty-eighth wall surface 323 along the circumference of the stator yoke 100 intersect with the seventh wall surface 321 and the eighth wall surface 322, respectively. In other words, W4 is the minimum distance between the intersection of the seventh wall surface 321 and the thirty-eighth wall surface 323 and the intersection of the eighth wall surface 322 and the thirty-eighth wall surface 323. When measuring W4, a vernier caliper can be used to measure the minimum distance between the intersection of the seventh wall surface 321 and the thirty-eighth wall surface 323 and the intersection of the eighth wall surface 322 and the thirty-eighth wall surface 323. Alternatively, on a projection plane perpendicular to the central axis of the stator yoke 100, the distance between the intersection of the projection of the seventh wall surface 321 and the projection of the thirty-eighth wall surface 323 and the intersection of the projection of the eighth wall surface 322 and the projection of the thirty-eighth wall surface 323 can be measured. The minimum distance W4 between the end of the seventh wall surface 321 facing away from the stator yoke 100 (i.e., the outer end) and the end of the eighth wall surface 322 facing away from the stator yoke 100 (i.e., the outer end) can be understood as the minimum tooth face width of the second tooth top 320.

[0086] Reference Figure 3 As shown, it can be understood that W1>W3, W2>W4, that is, the minimum tooth width of the first tooth portion 210 is greater than the minimum tooth width of the second tooth portion 310, and the minimum tooth face width of the first tooth top 220 is greater than the minimum tooth face width of the second tooth top 320. Therefore, it can be understood that the first stator tooth 200 is a wide tooth, and the second stator tooth 300 is a narrow tooth.

[0087] Reference Figure 2 As shown, it can be understood that the minimum distance between two adjacent first tooth tops 220 along the circumference of the stator yoke 100 is defined as L1. That is, L1 is the minimum distance between the two opposing walls of the two adjacent first tooth tops 220. To measure L1, a vernier caliper can be used to measure the position where the distance between the two opposing walls of the two adjacent first tooth tops 220 is the smallest. Generally speaking, the distance between the inner ends of the two opposing walls of the two adjacent first tooth tops 220 is the smallest. Therefore, L1 can also be obtained by directly measuring the distance between the inner end points of the projections of the two opposing walls of the two adjacent first tooth tops 220 on a projection plane perpendicular to the central axis of the stator yoke 100.

[0088] Reference Figure 2 As shown, it can be understood that along the circumference of the stator yoke 100, the minimum distance between the adjacent first tooth tops 220 and second tooth tops 320 is defined as L2, that is, L2 is the minimum width of the slot opening along the circumference of the stator yoke 100. When measuring L2, the vernier caliper can be used to measure the position where the distance between the two wall surfaces of the slot opening that are arranged opposite to each other along the circumference of the stator yoke 100 is the smallest. Generally speaking, the width of the slot opening is smallest at one end (i.e., the inner end) of the stator yoke 100. Therefore, the distance between the inner end points of the projections of the two wall surfaces of the slot opening that are arranged opposite to each other along the circumference of the stator yoke 100 can also be directly measured on a projection plane perpendicular to the central axis of the stator yoke 100 to obtain L2. L2 can be understood as the minimum width of the slot opening. L1>2*L2.

[0089] Reference Figure 2 As shown, it can be understood that the tooth surface of the first tooth top 220 and the tooth surface of the second tooth top 320 are on the same reference circle to ensure the roundness of the outer peripheral wall of the stator assembly.

[0090] Reference Figure 2 and Figure 4As shown, it can be understood that the stator assembly also includes a winding 400, which is wound around the first tooth portion 210. In addition, the first stator tooth 200 and the stator yoke 100 are an integral structure, which is easy to manufacture. The second stator tooth 300 is detachably connected to the stator yoke 100. For example, the second stator tooth 300 and the stator yoke 100 are matched with the stator yoke 100 through a dovetail slot structure. Therefore, when winding the first tooth portion 210, the second stator tooth 300 can be removed first to provide a large enough movement space for the winding nozzle. The space at the second stator tooth 300 can also be used as an exit space for the winding nozzle. Therefore, when winding, the tooth slot can be wound as full as possible, which is conducive to improving the slot fill rate and thus improving the performance of the motor. To facilitate the installation of the second stator tooth 300, a tooth insertion space 410 is left between the second stator tooth 300 and the winding 400 along the circumference of the stator yoke 100.

[0091] Reference Figure 1 As shown, it can be understood that in the motor, the direction of the magnetic flux lines is from a first permanent magnet 520 through the air gap 560, the first stator tooth 200, the stator yoke 100, the second stator tooth 300, the air gap 560, another adjacent permanent magnet, the rotor yoke 510 and returns to the first permanent magnet 520, thereby forming a closed-loop magnetic flux line.

[0092] Reference Figure 2 and Figure 3 As shown, it can be understood that the minimum tooth width W1 of the first tooth portion 210, the minimum tooth width W3 of the second tooth portion 310, the minimum tooth surface width W2 of the first tooth top 220, the minimum tooth surface width W4 of the second tooth top 320, the minimum distance L1 between two adjacent first tooth tops 220, and the minimum width L2 of the tooth groove satisfy: 10<(L1 / L2)*(W1 / W3)*(W2 / W4)<40.

[0093] Reference Figure 2 and Figure 3 As shown, it can be understood that (L1 / L2)*(W1 / W3)*(W2 / W4) is used to represent the output capacity of the motor, which is reflected in the output torque and output efficiency. The output torque includes two dimensions: back EMF and the linearity of the torque-current curve. The value of (L1 / L2)*(W1 / W3)*(W2 / W4) can be 15, 20, 25, or 30, etc.

[0094] Reference Figure 2 and Figure 3As shown, it can be understood that the tooth surface of the first tooth top 220 (i.e., the fourteenth wall surface and the fifteenth wall surface 225) and the tooth surface of the second tooth top 320 (i.e., the thirty-eighth wall surface 323) are both used to receive magnetic flux, wherein the tooth surface of the first tooth top 220 is the main wall surface for receiving magnetic flux. It is easy to understand that the area of ​​the tooth surface of the first tooth top 220 is positively correlated with the minimum tooth surface width W2 of the first tooth top 220, that is, the magnetic flux receiving area of ​​the first tooth top 220 is positively correlated with the minimum tooth surface width W2 of the first tooth top 220. Similarly, the area of ​​the tooth surface of the second tooth top 320 is positively correlated with the minimum tooth surface width W4 of the second tooth top 320, that is, the magnetic flux receiving area of ​​the second tooth top 320 is positively correlated with the minimum tooth surface width W4 of the second tooth top 320.

[0095] Reference Figure 2 and Figure 3 As shown, it can be understood that when the value of (L1 / L2)*(W1 / W3)*(W2 / W4) is too small, L1 and 2*L2 will tend to be equal, resulting in a too small minimum tooth face width W4 of the second tooth top 320, that is, the area for receiving magnetic flux of the second tooth top 320 is too small; at the same time, the magnetic flux density in the iron core is relatively large. Alternatively, W1 and W3 may tend to be equal. If both W1 and W3 are too small, that is, the minimum tooth width of the first tooth portion 210 is too small, the magnetic flux saturation of the first tooth portion 210 is high, and it is not conducive to fully utilizing the magnetic flux of the first permanent magnet 520. If both W1 and W3 are too large, the slot area will be too small, reducing the amount of windings accommodated by the motor, increasing copper loss, and affecting the output performance of the motor. It may also happen that W2 and W4 tend to be equal. If both W2 and W4 are too small, the total area receiving magnetic flux is too small. If both W2 and W4 are too large, when the circumferential space along the stator yoke 100 is limited, the second tooth top 320 occupies the space of the first tooth top 220 and serves as the main wall surface for receiving magnetic flux. The minimum tooth surface width of the tooth surface of the first tooth top 220 is insufficient, that is, the area receiving magnetic flux of the first tooth top 220 is insufficient, and the total area receiving magnetic flux is small.

[0096] When the value of (L1 / L2)*(W1 / W3)*(W2 / W4) is too large, L1 may be much larger than 2*L2. Although this helps ensure the magnetic flux receiving area of ​​the second tooth top 320, because the second tooth top 320 competes with the first tooth top 220 for space in the circumferential direction of the stator yoke 100, a large L1 may result in the minimum tooth face width W2 of the first tooth top 220 being too small, that is, the magnetic flux receiving area of ​​the first tooth top 220 is too small. Alternatively, when W1 is much larger than W3, if the space along the circumference of the stator yoke 100 is limited, the minimum tooth width of the second tooth portion 310 may be too small, resulting in a high degree of magnetic flux saturation in the second tooth portion 310, which is not conducive to fully utilizing the magnetic flux of the first permanent magnet 520. It may also happen that W2 is much larger than W4. When the circumferential space along the stator yoke 100 is limited, the minimum tooth surface width of the tooth surface of the second tooth top 320 will be too small, that is, the magnetic flux receiving area of ​​the second tooth top 320 is too small, and the total magnetic flux receiving area is small.

[0097] Therefore, by setting 10 to be less than (L1 / L2)*(W1 / W3)*(W2 / W4)<40 and limiting the value of (L1 / L2)*(W1 / W3)*(W2 / W4) to an appropriate range, the structural dimension ratio of the first stator tooth 200 and the second stator tooth 300 can be optimized, so that the total magnetic flux receiving area of ​​the first stator tooth 200 and the second stator tooth 300 is maximized within a limited space, the total received magnetic flux is maximized, copper loss is minimized, and the magnetic flux density in the iron core is reduced to reduce iron loss, thereby maximizing the total magnetic flux linkage and total back electromotive force. At the same time, the magnetic circuit saturation degree of the first stator tooth 200 and the second stator tooth 300 is minimized, thereby optimizing the linearity of the motor torque-current curve, thereby improving the overall output capacity of the motor and improving the overall efficiency.

[0098] Reference Figure 3 、 Figure 5 and Figure 6As shown, it can be understood that the second stator tooth 300 and the stator yoke 100 cooperate through a dovetail groove structure to achieve a detachable connection between the second stator tooth 300 and the stator yoke 100. Specifically, the second tooth portion 310 includes a mounting portion 313, which is located at one end of the second tooth portion 310 close to the central axis of the stator yoke 100. Correspondingly, a first mounting slot 110 is provided on the outside of the stator yoke 100, with the notch of the first mounting slot 110 facing the outside of the stator yoke 100. The outer profile of the mounting portion 313 matches the inner profile of the first mounting slot 110. That is, on a projection plane perpendicular to the central axis of the stator yoke 100, the projection of the mounting portion 313 is the same as the projection of the first mounting slot 110. The mounting portion 313 is inserted into the first mounting slot 110 along the central axis of the stator yoke 100, so that the mounting portion 313 is accommodated in the first mounting slot 110, thereby achieving a detachable connection between the second stator tooth 300 and the stator yoke 100. This facilitates the removal of the second stator tooth 300 before winding the wire on the first stator tooth 200, providing ample room for the winding nozzle to move. The space at the second stator tooth 300 also serves as an exit space for the winding nozzle. Therefore, the tooth slots can be wound as fully as possible during winding, which helps to increase the slot fill rate and thus improve the performance of the motor.

[0099] Reference Figure 6 As shown, it can be understood that the first mounting slot 110 includes a first slot segment 111 and a second slot segment 112, wherein the second slot segment 112 is located at the end of the first slot segment 111 that faces away from the central axis of the stator yoke 100, and an intermediate slot segment 113 is connected between the first slot segment 111 and the second slot segment 112. In other words, the first slot segment 111 is located at the end of the first mounting slot 110 that is closer to the central axis of the stator yoke 100. Along the circumference of the stator yoke 100, the first mounting slot 110 has a ninth wall surface 114 and a tenth wall surface 115 that are arranged opposite each other. In a direction perpendicular to the radial direction of the stator yoke 100, the distance between the ninth wall surface 114 and the tenth wall surface 115 is defined as the width of the first mounting slot 110. From the stator yoke 100 toward the second tooth top 320, that is, in the radially outward direction of the stator yoke 100, the width of the first mounting slot 110 decreases at the first slot segment 111, and increases at the second slot segment 112. It is easy to understand that, to facilitate machining and to provide a transition between the first slot segment 111 and the second slot segment 112, the width of the first mounting slot 110 remains unchanged at the intermediate slot segment 113. Therefore, the partial structure of the mounting portion 313 at the first slot segment 111 prevents the second stator tooth 300 from detaching from the stator yoke 100 radially outward, thereby improving the bond between the second stator tooth 300 and the stator yoke 100. The partial structure of the mounting portion 313 at the second slot segment 112 facilitates the transition between the mounting portion 313 and the second tooth portion 310, facilitating machining.

[0100] Reference Figure 6 As shown, it can be understood that along the circumference of the stator yoke 100, the maximum width of the first mounting slot 110 is defined as Y1, and the minimum width of the first mounting slot 110 is defined as Y2. In this embodiment, the width of the first mounting slot 110 is greatest at the slot opening, and the maximum width of the first mounting slot 110 is equal to the tooth width of the second tooth portion 310. When measuring Y1, the width of the first mounting slot 110 at the slot opening can be directly measured using a vernier caliper. The width of the first mounting slot 110 is smallest at the middle slot section 113. When measuring Y2, the width of the middle slot section 113 can be directly measured using a vernier caliper.

[0101] Reference Figure 6 As shown, it can be understood that the maximum width Y1 of the first mounting groove 110 and the minimum width Y2 of the first mounting groove 110 satisfy the following relationship: 1 < Y1 / Y2 < 3. The value of Y1 / Y2 can be 1.5, 2, or 2.5, for example. Since Y1>Y2, Y1 / Y2 must be greater than 1. Setting Y1 / Y2 < 3 prevents the minimum width Y2 of the first mounting groove 110 from being too small, which would affect the machining of the first mounting groove 110, while maintaining the value of Y1. This improves machinability. Furthermore, because the mounting portion 313 matches the first mounting groove 110, the width of the mounting portion 313 at the middle slot section 113 is not too small, which helps ensure the structural strength of the mounting portion 313. While maintaining the value of Y2, this prevents the maximum width Y1 of the first mounting groove 110 from being too large, which would increase the radial dimension of the first mounting groove 110 along the stator yoke 100 and reduce the structural strength of the stator yoke 100.

[0102] Therefore, by setting 1 < Y1 / Y2 < 3, the structural strength of the mounting portion 313 and the stator yoke 100 can be ensured. It is easy to understand that within the range of 1 < Y1 / Y2 < 3, the larger the maximum width Y1 of the first mounting slot 110, the larger the contact area between the second stator tooth 300 and the stator yoke 100, and the better the bonding.

[0103] Reference Figure 6As shown, it can be understood that, along the radial direction of the stator yoke 100, the stator yoke 100 has an eleventh wall surface 120 and a twelfth wall surface 130, which are opposite to each other. The eleventh wall surface 120 is closer to the central axis of the stator yoke 100 than the twelfth wall surface 130. That is, the eleventh wall surface 120 is the inner wall surface of the stator yoke 100, and the twelfth wall surface 130 is the outer wall surface of the stator yoke 100. The first mounting slot 110 has a thirteenth wall surface 116, which is opposite to the eleventh wall surface 120. That is, the thirteenth wall surface 116 is the wall surface of the first mounting slot 110 opposite to the slot opening (i.e., the slot bottom). The minimum distance between the eleventh wall surface 120 and the twelfth wall surface 130 is defined as W5, which can be understood as the radial width of the stator yoke 100. The minimum distance between the thirteenth wall surface 116 and the eleventh wall surface 120 is W6, satisfying the following: 0.2<(W5-W6) / W5<0.8. (W5-W6) / W5 represents the ratio of the radial depth of the first mounting slot 110 to the width of the stator yoke 100. It is easy to understand that the larger the value of (W5-W6) / W5, the larger the contact area between the second stator tooth 300 and the stator yoke 100, and the better the bonding. However, at the same time, the strength of the stator yoke 100 will be reduced. Therefore, 0.2<(W5-W6) / W5<0.8, while ensuring that the strength of the stator yoke 100 meets the requirements, maximizes the bonding between the second stator tooth 300 and the stator yoke 100.

[0104] Reference Figure 7 As shown, it can be understood that the maximum outer diameter of the rotor assembly 500 is defined as D1, and the minimum inner diameter of the rotor assembly 500 is defined as D2. It is easy to understand that the maximum outer diameter D1 of the rotor assembly 500 is the maximum outer diameter of the rotor yoke 510. When measuring D1, a vernier caliper can be used to measure the maximum outer diameter of the rotor yoke 510. The minimum inner diameter D2 of the rotor assembly 500 is twice the minimum distance from the side wall (i.e., the inner wall) of any first permanent magnet 520 facing the central axis of the rotor yoke 510 to the central axis of the rotor yoke 510. When measuring D2, the minimum distance from the projection of the inner wall of the first permanent magnet 520 to the central axis of the rotor yoke 510 on a projection plane perpendicular to the central axis of the rotor yoke 510 can be measured. D2 is twice this minimum distance. D1>D2. The central axis of the rotor yoke 510 is the central axis of the rotor assembly 500.

[0105] Reference Figure 3 and Figure 7As shown, it can be understood that the minimum tooth width W1 of the first tooth portion 210, the minimum tooth width W3 of the second tooth portion 310, the maximum outer diameter D1 of the rotor assembly 500, and the minimum inner diameter D2 of the rotor assembly 500 satisfy the following relationship: 0.8 < (W1 / W3)*(D2 / D1) < 1.9. The value of (W1 / W3)*(D2 / D1) can be 0.9, 1, 1.2, 1.5, etc.

[0106] When (W1 / W3)*(D2 / D1) is too small, W1 and W3 tend to be equal. If both W1 and W3 are too small, that is, the minimum tooth width of the first tooth portion 210 is too small, the first tooth portion 210 reaches a high degree of magnetic flux saturation, which is not conducive to fully utilizing the magnetic flux of the first permanent magnet 520. If both W1 and W3 are too large, the slot area is too small, reducing the amount of windings that can be accommodated by the motor, increasing copper loss, and affecting the motor's output performance. A large difference between D1 and D2 is beneficial for increasing the radial thickness of the first permanent magnet 520 along the rotor yoke 510 to enhance the magnetic field. Increasing the radial thickness of the rotor yoke 510 prevents magnetic flux saturation in the rotor yoke 510, which helps improve the motor's output torque and efficiency.

[0107] When (W1 / W3)*(D2 / D1) is too large, W1 will be much larger than W3. Given the limited circumferential space along the stator yoke 100, the minimum tooth width of the second tooth portion 310 will be too small, resulting in a high degree of magnetic flux saturation in the second tooth portion 310, which is not conducive to fully utilizing the magnetic flux of the first permanent magnet 520. When D1 and D2 are close to being equal, the radial thickness of the first permanent magnet 520 and the radial thickness of the rotor yoke 510 are both small, resulting in a low magnetic field strength and a high tendency for magnetic flux saturation in the rotor yoke 510. This results in low motor output torque and low efficiency, affecting motor performance.

[0108] Therefore, by setting 0.8<(W1 / W3)*(D2 / D1)<1.9, the output performance of the motor can be optimized.

[0109] Reference Figure 3 and Figure 7 As shown, it can be understood that the minimum tooth face width W2 of the first tooth tip 220, the minimum tooth face width W4 of the second tooth tip 320, the maximum outer diameter D1 of the rotor assembly 500, and the minimum inner diameter D2 of the rotor assembly 500 satisfy the following relationship: 1.4 < (W2 / W4) * (D2 / D1) < 3.2. The value of (W2 / W4) * (D2 / D1) can be 1.8, 2, 2.2, 2.4, etc.

[0110] When (W2 / W4)*(D2 / D1) is too small, W2 and W4 tend to be equal. If both W2 and W4 are too small, the total area receiving magnetic flux is too small. If both W2 and W4 are too large, given the limited circumferential space along the stator yoke 100, the second tooth top 320 occupies the space of the first tooth top 220, serving as the primary wall surface for receiving magnetic flux. The minimum tooth face width of the first tooth top 220 is insufficient, meaning that the area receiving magnetic flux at the first tooth top 220 is insufficient, resulting in a small total area receiving magnetic flux. A large difference between D1 and D2 facilitates increasing the radial thickness of the first permanent magnet 520 along the rotor yoke 510 to enhance the magnetic field, and also increases the radial thickness of the rotor yoke 510 to reduce the risk of magnetic flux saturation in the rotor yoke 510, thereby improving the motor's output torque and efficiency.

[0111] When (W2 / W4)*(D2 / D1) is too large, W2 will be much larger than W4. Given the limited circumferential space along the stator yoke 100, the minimum tooth face width of the second tooth tip 320 will be too small. This means that the magnetic flux receiving area of ​​the second tooth tip 320 is too small, resulting in a small total magnetic flux receiving area. When D1 and D2 are equal, the radial thickness of the first permanent magnet 520 and the radial thickness of the rotor yoke 510 are both small, resulting in a weak magnetic field strength and a tendency for magnetic flux saturation in the rotor yoke 510. This results in low motor output torque and low efficiency, impacting motor performance.

[0112] Therefore, by setting 1.4<(W2 / W4)*(D2 / D1)<3.2, the output performance of the motor can be optimized.

[0113] Reference Figure 1 and Figure 3 As shown, it can be understood that since the first groove 223 is located at the rear end of the first stator tooth 200 along the first direction, when the rotor assembly 500 rotates in the forward direction, the first permanent magnet 520 of the rotor assembly 500 sequentially passes through the second tooth top 320, the tooth groove between the second tooth top 320 and the first tooth top 220, the fourteenth wall 224, the first groove 223, the fifteenth wall 225, the tooth groove between the first tooth top 220 and another adjacent second tooth top 320, and the aforementioned another adjacent second tooth top 320.

[0114] Reference Figure 9The graph shows how the torque ripple of the motor varies with the distance from the notch of the first groove 223 to the symmetric centerline of the first stator tooth 200. In the graph, when the distance from the notch of the first groove 223 to the symmetric centerline of the first stator tooth 200 is a negative value, it indicates that the notch of the first groove 223 is located at the rear end of the first stator tooth 200 along the first direction. When the distance from the notch of the first groove 223 to the symmetric centerline of the first stator tooth 200 is a positive value, it indicates that the notch of the first groove 223 is located at the front end of the first stator tooth 200 along the first direction. As can be seen from the graph, the torque ripple is generally smaller when the notch of the first groove 223 is located at the rear end of the first stator tooth 200 along the first direction than when the notch of the first groove 223 is located at the front end of the first stator tooth 200 along the first direction. Therefore, by positioning the first groove 223 at the rear end of the first stator tooth 200 along the first direction, the torque ripple of the motor can be significantly reduced, facilitating smooth operation of the motor.

[0115] Reference Figure 3 As shown, it can be understood that the minimum distance between the ends of the fifteenth wall surface 225 along the circumference of the stator yoke 100 is defined as W7. It is also easy to understand that the distance between the ends of the fifteenth wall surface 225 along the circumference of the stator yoke 100 is equal at all locations along the central axis of the stator yoke 100. Therefore, when measuring W7, the distance between the ends of the projection of the fifteenth wall surface 225 can be directly measured on a projection plane perpendicular to the central axis of the stator yoke 100. It is easy to understand that, compared to the fourteenth wall surface 224, the fifteenth wall surface 225 is the primary wall surface for the first stator tooth 200 to receive magnetic flux.

[0116] Reference Figure 7 As shown, it can be understood that along the circumference of the rotor yoke 510, the first permanent magnet 520 has a sixteenth wall surface 521 and a seventeenth wall surface 522 that are separated from each other, and the maximum distance between the sixteenth wall surface 521 and the seventeenth wall surface 522 is defined as W8. In this embodiment, the projection of the first permanent magnet 520 on a projection plane perpendicular to the central axis of the rotor yoke 510 is generally an arc-shaped structure. The maximum distance W8 between the sixteenth wall surface 521 and the seventeenth wall surface 522 is the distance between the two ends of the side wall surface (i.e., the outer wall surface) of the first permanent magnet 520 that faces away from the central axis of the rotor yoke 510 along the circumference of the rotor yoke 510, that is, the maximum width of the first permanent magnet 520. Therefore, when measuring W2, the distance between the two ends of the outer wall surface of the first permanent magnet 520 along the circumference of the rotor yoke 510 can be measured using a vernier caliper. Alternatively, the distance between the outer end point of the projection of the sixteenth wall surface 521 and the outer end point of the projection of the seventeenth wall surface 522 may be measured on a projection plane perpendicular to the central axis of the rotor yoke 510 .

[0117] Reference Figure 3 and Figure 7As shown, it can be understood that the minimum distance W7 between the ends of the fifteenth wall 225 along the circumferential direction of the stator yoke 100, the maximum distance W8 between the sixteenth wall 521 and the seventeenth wall 522, the maximum outer diameter D1 of the rotor assembly 500, and the minimum inner diameter D2 of the rotor assembly 500 satisfy the following: 0.6 < (W7 / W8) * (D2 / D1) < 1.11. (W7 / W8) * (D2 / D1) is used to comprehensively evaluate the performance of the motor, including output torque and efficiency. (W7 / W8) * (D2 / D1) can be 0.8, 0.9, 1, 1.1, etc. When (W7 / W8)*(D2 / D1) is too small, W7 will be much smaller than W8, resulting in a smaller area for the first stator tooth 200 to receive the magnetic flux. The first stator tooth 200 will experience magnetic flux saturation and will not be able to fully utilize the magnetic field of the first permanent magnet 520, resulting in low output torque and low efficiency of the motor, affecting the performance of the motor; and the difference between D1 and D2 is large, which is beneficial to increase the radial thickness of the first permanent magnet 520 along the rotor yoke 510 to enhance the magnetic field, and increase the radial thickness of the rotor yoke 510 to prevent the rotor yoke 510 from being prone to magnetic flux saturation, which is beneficial to improving the output torque and efficiency of the motor. When (W7 / W8)*(D2 / D1) is too large, W7>W8 will occur, and the first stator tooth 200 is not prone to magnetic flux saturation. The area of ​​the first stator tooth 200 receiving magnetic flux is large, and the magnetic field of the first permanent magnet 520 can be fully utilized, which is beneficial to improving the output torque and efficiency of the motor; while D1 and D2 tend to be equal, resulting in the radial thickness of the first permanent magnet 520 along the rotor yoke 510 and the radial thickness of the rotor yoke 510 being small, the magnetic field strength is small, and the rotor yoke 510 is prone to magnetic flux saturation, resulting in low output torque and low efficiency of the motor, affecting the performance of the motor.

[0118] Therefore, by making 0.6<(W7 / W8)*(D2 / D1)<1.11, the value of (W7 / W8)*(D2 / D1) is within an appropriate range, which can maximize the output torque and efficiency of the motor and is conducive to improving the performance of the motor.

[0119] Reference Figure 3As shown, it can be understood that, along the circumference of the stator yoke 100 , the minimum distance defining the first groove 223 at the notch is W9 . Specifically, along the circumference of the stator yoke 100, the first groove 223 has an eighteenth wall 2231 and a nineteenth wall 2232 that are relatively arranged, wherein the eighteenth wall 2231 is located on the side close to the fourteenth wall 224, and the nineteenth wall 2232 is located on the side close to the fifteenth wall 225. The minimum distance W9 of the first groove 223 at the slot is the minimum distance from the intersection of the eighteenth wall 2231 and the fourteenth wall 224 to the intersection of the nineteenth wall 2232 and the fifteenth wall 225. When measuring W9, on the projection plane perpendicular to the central axis of the stator yoke 100, measure the distance from the intersection point of the projection of the eighteenth wall 2231 and the projection of the fourteenth wall 224 to the intersection point of the projection of the nineteenth wall 2232 and the projection of the fifteenth wall 225.

[0120] Reference Figure 7 As shown, it can be understood that the minimum distance between the two opposite walls of two adjacent first permanent magnets 520 is defined as W 10 , W 10 That is, the minimum distance between the intersections of the two opposite walls of two adjacent first permanent magnets 520 and the inner wall of each first permanent magnet 520. 10 When the distance between the two opposite walls of two adjacent first permanent magnets 520 and the inner wall is the shortest, the position can be obtained by using a vernier caliper.

[0121] Reference Figure 3 and Figure 7 As shown, it can be understood that the minimum distance W9 between the first groove 223 at the notch and the minimum distance W between the two opposite walls of the two adjacent first permanent magnets 520 is 10 Satisfy 0.5<W9 / W 10 <2. For example, W9 / W 10 =0.6, W9 / W 10 =1.0, W9 / W 10 =1.5 etc. When W9 / W 10 Too big or too small will result in W9 and W 10 A large difference in W9 / W will cause the motor's cogging torque to deteriorate, affecting the motor's efficiency and stability. 10 In the appropriate range, make W9 and W 10 The difference is within a reasonable range to reduce the motor's cogging torque as much as possible.

[0122] Reference Figure 8As shown, it can be understood that the first tooth top 220 is also provided with a second groove 226, and the second groove 226 is located on the other side of the first tooth top 220 protruding from the first tooth portion 210, that is, the second groove 226 and the first groove 223 are respectively located on both sides of the symmetrical centerline of the first stator tooth 200 along the circumferential direction of the stator yoke 100. The structure of the second groove 226 can refer to the structure of the first groove 223 and will not be repeated here. At this time, the notch of the second groove 226 also faces the rotor assembly 500. It is easy to understand that the minimum distance from the first groove 223 to the symmetrical centerline of the first stator tooth 200 and the minimum distance from the second groove 226 to the symmetrical centerline of the first stator tooth 200 can be equal or unequal.

[0123] Therefore, by further arranging a second groove 226 on the first tooth top 220, the second groove 226 can also be regarded as another structure of the tooth slot, which is equivalent to further increasing the number of tooth slots of the stator assembly. During the rotation of the rotor assembly 500, the pulsation number of the tooth slot torque can be further increased by further increasing the number of tooth slots, thereby further reducing the pulsation amplitude of the tooth slot torque, thereby further reducing the tooth slot torque and reducing the torque pulsation at the same time, which is conducive to smoother operation of the motor.

[0124] Reference Figure 8 As shown, it can be understood that the second groove 226 and the first groove 223 are symmetrically arranged about the symmetric centerline of the first stator tooth 200. In other words, the minimum distance between the first groove 223 and the symmetric centerline of the first stator tooth 200 is equal to the minimum distance between the second groove 226 and the symmetric centerline of the first stator tooth 200. Because the rotor assembly 500 can rotate in both a counterclockwise direction and a clockwise direction, the symmetrical arrangement of the first groove 223 and the second groove 226 can equally reduce cogging torque and torque ripple regardless of whether the rotor assembly 500 rotates forward or reverse, while meeting the performance requirements of the motor in both forward and reverse rotation conditions.

[0125] Reference Figure 8 As shown, it is easy to understand that the first groove 223 and the second groove 226 are both arranged on the first tooth top 220 with a larger width. On the one hand, it is convenient for processing. On the other hand, the first tooth top 220 with a larger width can be approximately divided into a plurality of teeth arranged at circumferential intervals along the stator yoke 100 to increase the number of pulsations of the tooth slot torque, which is beneficial to reducing the tooth slot torque and torque pulsation.

[0126] It is easy to understand that in the prior art, since the permanent magnets of the permanent magnet motor are in the shape of tiles, they are limited by the external dimensions of the motor. Generally speaking, the thickness of the tile-shaped permanent magnets is small, the air gap magnetic flux density is small, and the motor using this type of permanent magnet has the problem that the magnetic field density distribution deviates from the sinusoidal waveform, the harmonics are large, the reluctance torque and the cogging torque increase, which leads to increased iron loss, lower output torque of the motor, and reduced efficiency of the motor.

[0127] To this end, the structure of the first permanent magnet 520 is described in detail below.

[0128] Reference Figure 10 and Figure 11 As shown, it can be understood that, along the radial direction of the rotor yoke 510, the first permanent magnet 520 has a twenty-second wall surface 523 and a twenty-third wall surface 524 that are separated from each other. The twenty-second wall surface 523 is located on the side of the first permanent magnet 520 that is away from the rotation axis Z1 of the rotor yoke 510, and the twenty-third wall surface 524 is the wall surface of the first permanent magnet 520 that faces the stator assembly. Generally speaking, the twenty-second wall surface 523 is an arc or other curved surface. Therefore, on a projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510, the projection of the twenty-second wall surface 523 is an arc or other curved line. Along the circumference of the rotor yoke 510, the projection of the twenty-second wall surface 523 has endpoints at both ends.

[0129] Reference Figure 1 、 Figure 10 and Figure 11 As shown, it can be understood that, on a projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510, a circle with the projection of the rotation axis Z1 of the rotor yoke 510 as its center and the minimum distance between the end of the projection of the twenty-second wall surface 523 and the center as its radius is the first reference circle 600. Generally speaking, the two ends of the projection of the twenty-second wall surface 523 are equidistant from the center of the circle. The twenty-second wall surface 523 is arranged to protrude toward the side away from the rotation axis Z1 of the rotor yoke 510 relative to the first reference circle 600, thereby forming a convex portion on the portion of the first permanent magnet 520 located on the side of the first reference circle 600 away from the rotation axis Z1 of the rotor yoke 510. In other words, the convex portion is located on the side of the first permanent magnet 520 away from the rotation axis Z1 of the rotor yoke 510 and extends from one end of the first permanent magnet 520 to the other end of the first permanent magnet 520 along the circumference of the rotor yoke 510. Since the first permanent magnet 520 is located on the inner periphery of the rotor yoke 510, and the rotor yoke 510 is wound around the outer periphery of the stator assembly, the protrusion is located on the side of the first permanent magnet 520 away from the stator assembly, and the protrusion is protruded in the direction away from the stator assembly, that is, the protrusion is protruded toward the rotor yoke 510.

[0130] Reference Figure 11As shown, it can be understood that the twenty-third wall surface 524 can also be an arc surface, other curved surfaces or a plane, and an air gap 560 is formed between the twenty-third wall surface 524 and the tooth surface of the first tooth top 220, and between the twenty-third wall surface 524 and the tooth surface of the second tooth top 320.

[0131] Reference Figure 11 As shown, it can be understood that the first permanent magnet 520 is an axisymmetric structure, and the first permanent magnet 520 has a symmetric center line. The symmetric center line of the first permanent magnet 520 is arranged along the radial direction of the rotor yoke 510 and intersects with the rotation axis Z1 of the rotor yoke 510, that is, the symmetric center line of the first permanent magnet 520 is perpendicular to the rotation axis Z1 of the rotor yoke 510, and the first permanent magnet 520 is symmetrically arranged about its own symmetric center line.

[0132] Reference Figure 10 As shown, it can be understood that, on the projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510, the distance from the projection of the twenty-second wall surface 523 to the first reference circle 600 decreases from the symmetry center line of the first permanent magnet 520 to both sides along the circumference of the rotor yoke 510.

[0133] Reference Figure 11 As shown, it can be understood that the vertical distance from the twenty-second wall surface 523 to the twenty-third wall surface 524 is the thickness of the first permanent magnet 520. From the symmetric centerline of the first permanent magnet 520 toward both sides along the circumference of the rotor yoke 510, the thickness of the first permanent magnet 520 decreases. In other words, the first permanent magnet 520 has a structure with a larger thickness in the middle and a smaller thickness at both ends along the circumference of the rotor yoke 510. Therefore, by increasing the thickness of the first permanent magnet 520, the magnetic field strength can be increased, thereby increasing the magnetic field strength at the air gap 560, that is, increasing the air gap flux density, and thus improving the output torque of the motor.

[0134] At the same time, the magnetic flux of the magnetic field of the first permanent magnet 520 is concentrated at the middle position of the first permanent magnet 520, achieving an optimized magnetic flux distribution and spatially making the magnetic flux distribution closer to a sine waveform. According to the formula Bg = br*Hpm / (Hpm+gap), Bg is the air gap magnetic flux, br is the permanent magnet remanence, Hpm is the permanent magnet thickness, and gap is the thickness of the air gap 560. Increasing the thickness Hpm of the first permanent magnet 520 can increase the air gap magnetic flux Bg to a certain extent. Therefore, the air gap magnetic flux near the middle position of the first permanent magnet 520 is larger, and the air gap magnetic flux near the two ends of the first permanent magnet 520 along the circumferential direction of the rotor yoke 510 is smaller, making the air gap magnetic flux distribution closer to a sine waveform, reducing the harmonic component of the air gap magnetic flux, reducing iron loss, and thus reducing the reluctance torque and cogging torque, thereby improving the output torque and efficiency of the motor and improving the running smoothness of the motor.

[0135] Reference Figure 11 As shown, it can be understood that the maximum thickness of the first permanent magnet 520 is defined as T1, and the minimum thickness of the first permanent magnet 520 is defined as T2. It is easy to understand that the thickness of the first permanent magnet 520 is the largest at the middle position, and the thickness of the first permanent magnet 520 is the smallest at both ends of the rotor yoke 510 along the circumferential direction, and the thickness of the first permanent magnet 520 at both ends of the rotor yoke 510 along the circumferential direction is equal. That is, on a projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510, the maximum thickness T1 of the first permanent magnet 520 is the distance from the intersection of the symmetry centerline of the first permanent magnet 520 and the projection of the twenty-second wall 523 to the intersection of the symmetry centerline of the first permanent magnet 520 and the projection of the twenty-third wall 524. The minimum thickness T2 of the first permanent magnet 520 is the distance from the intersection of the projection of the twenty-second wall 523 and the projection of the sixteenth wall 521 to the intersection of the projection of the twenty-third wall 524 and the projection of the sixteenth wall 521. When measuring T1, a vernier caliper can be used to measure at the position where the distance between the twenty-second wall 523 and the twenty-third wall 524 is the greatest. When measuring T2, a vernier caliper can be used to measure at the position where the distance between the twenty-second wall 523 and the twenty-third wall 524 is the smallest. In this case, T1>T2.

[0136] Reference Figure 7 and Figure 11As shown, it can be understood that the maximum thickness T1 of the first permanent magnet 520, the minimum thickness T2 of the first permanent magnet 520, the maximum outer diameter D1 of the rotor assembly 500, and the minimum inner diameter D2 of the rotor assembly 500 satisfy the following: 0.838 < (T1 / T2) * (D2 / D1) < 1.7. (T1 / T2) * (D2 / D1) is used to comprehensively evaluate the distribution and magnitude of the air gap flux density. (T1 / T2) * (D2 / D1) can be 0.95, 1, 1.1, 1.2, etc. When (T1 / T2)*(D2 / D1) is too small, T1 and T2 tend to be equal, that is, the maximum thickness and the minimum thickness of the first permanent magnet 520 tend to be equal, which will cause the air gap magnetic flux distribution to deviate from the sinusoidal waveform, and the harmonics of the air gap magnetic flux are large, which is not conducive to improving the output torque and efficiency of the motor; and the difference between D1 and D2 is large, that is, when the thickness of the first permanent magnet 520 does not change much, the radial distance from the outer peripheral wall to the inner peripheral wall of the rotor yoke 510 (that is, the thickness of the rotor yoke 510) is large, and the magnetic flux is not easy to saturate when passing through the rotor yoke 510, that is, the magnetic circuit saturation degree of the rotor yoke 510 is low, so that the magnetic flux of the first permanent magnet 520 can be fully utilized, which is beneficial to increase the air gap magnetic flux and thus improve the output torque of the motor. When (T1 / T2)*(D2 / D1) is too large, the difference between T1 and T2 is large, that is, the difference between the maximum thickness and the minimum thickness of the first permanent magnet 520 is large, which is conducive to the air gap magnetic density distribution being closer to a sine waveform, thereby reducing the harmonics of the air gap magnetic density and improving the output torque and efficiency of the motor; while D1 and D2 tend to be equal, that is, when the thickness of the first permanent magnet 520 does not change much, the thickness of the rotor yoke 510 is small, and saturation is likely to occur when the magnetic flux passes through the rotor yoke 510, resulting in the inability to fully utilize the magnetic flux of the first permanent magnet 520, reducing the air gap magnetic density, and being unfavorable for improving the output torque of the motor.

[0137] Therefore, by making 0.838<(T1 / T2)*(D2 / D1)<1.7, the air gap flux density distribution can be made closer to a sine waveform, while maximizing the air gap flux density, thereby increasing the output torque and efficiency of the motor and improving the running smoothness of the motor.

[0138] Reference Figure 1As shown, it can be understood that on the projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510, the projection of the twenty-second wall surface 523 is an arc, and the projection of the twenty-second wall surface 523 is defined as a first arc. The circle on which the first arc is located is the second reference circle 700, and the center of the second reference circle 700 is staggered with the rotation axis Z1 of the rotor yoke 510. Specifically, the center of the second reference circle 700 is located between the rotation axis Z1 of the rotor yoke 510 and the first permanent magnet 520, and the center of the second reference circle 700 coincides with the symmetry center line of the first permanent magnet 520. Therefore, the convex portion is an arc-shaped convex structure, which is conducive to making the air gap magnetic flux distribution closer to a sine waveform, thereby improving the torque and efficiency of the motor and improving the allowable stability of the motor. The convex portion of the arc-shaped convex structure has a simple structure and is easy to process.

[0139] In other embodiments, it is understood that, on a projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510, the projection of the twenty-second wall surface 523 includes multiple arc segments, which are arranged to protrude away from the stator assembly. The multiple arc segments are sequentially connected along the circumference of the rotor yoke 510. Generally speaking, the multiple arc segments are smoothly connected. Therefore, the convex portion of this structure can also make the air gap flux density distribution closer to a sine waveform, thereby improving the torque and efficiency of the motor and improving the motor's allowable stability.

[0140] Reference Figure 11 As shown, it can be understood that the first permanent magnet 520 is magnetized in a concentrated magnetic manner so as to adjust the distribution of the magnetic field of the first permanent magnet 520 according to specific needs and achieve more precise magnetization control. Specifically, in this embodiment, on the projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510, the projection of the twenty-second wall surface 523 is a first arc. In other words, the twenty-second wall surface 523 is a continuous arc surface structure. Along the circumference of the rotor yoke 510, the tangent at one end of the first arc is taken, and the straight line perpendicular to the tangent is defined as the first straight line Z2. The angle between the first straight line Z2 and the center line of symmetry of the first permanent magnet 520 is θ, which satisfies: θ ≥ 10°. It is easy to understand that the direction of the symmetry center line of the first permanent magnet 520 is related to the ferrite crystal orientation at the middle position of the first permanent magnet 520, and the direction of the first straight line Z2 is related to the ferrite crystal orientation at the end of the first permanent magnet 520 along the circumference of the rotor yoke 510. Therefore, the angle θ between the first straight line Z2 and the symmetry center line of the first permanent magnet 520 can be used to approximately represent the angle between the ferrite crystal orientation at the middle position of the first permanent magnet 520 and the ferrite crystal orientation at the end, that is, the angle θ between the first straight line Z2 and the symmetry center line of the first permanent magnet 520 is related to the angle between the ferrite crystal orientation at the middle position of the first permanent magnet 520 and the ferrite crystal orientation at the end.

[0141] Reference Figure 11 As shown, it can be understood that the angle θ between the first straight line Z2 and the symmetric center line of the first permanent magnet 520 satisfies: θ≥10°. On the one hand, it meets the manufacturing requirements of the first permanent magnet 520 and can adjust the distribution of the magnetic field of the first permanent magnet 520 so that the magnetic flux is concentrated in the middle position of the first permanent magnet 520. In space, the magnetic flux distribution is closer to a sinusoidal waveform, so that the air gap magnetic flux distribution is also closer to a sinusoidal waveform, reducing the harmonic component of the air gap magnetic flux and reducing iron loss, thereby reducing the reluctance torque and cogging torque, thereby achieving the improvement of the output torque and efficiency of the motor and improving the running stability of the motor.

[0142] Reference Figure 10 and Figure 11 As shown, it can be understood that, on the other hand, by making θ≥10°, the ferrite crystal orientation at the end of the first permanent magnet 520 is changed, so that in addition to the twenty-second wall 523 generating magnetic flux, the sixteenth wall 521 and the seventeenth wall 522 can also generate magnetic flux, thereby increasing the magnetic field strength of the first permanent magnet 520, and then increasing the air gap magnetic density, thereby further improving the output torque of the motor.

[0143] Reference Figure 14 As shown, Figure 14 The following are curves of the torque variation of the motor under different schemes over a period of time. Scheme 1 is that the 22nd wall surface 523 of the first permanent magnet 520 is protruded relative to the first reference circle 600 toward the side away from the rotation axis Z1 of the rotor yoke 510; Scheme 2 is Scheme 1 combined with θ≥10°. Figure 14 It can be seen that the torque of the motor of Solution 1 is greater than the torque of the motor of the prior art, and the torque of the motor of Solution 2 is greater than the torque of the motor of Solution 1. In other words, Solution 1 can improve the torque of the motor, and Solution 2 can further improve the torque of the motor.

[0144] Reference Figure 10 and Figure 12As shown, it can be understood that the rotor yoke 510 is provided with recesses 511. Specifically, the recesses 511 are located on the side of the rotor yoke 510 facing the rotation axis Z1 of the rotor yoke 510, that is, the recesses 511 are located on the inner side of the rotor yoke 510. The number of recesses 511 is equal to the number of first permanent magnets 520. Generally speaking, the portion of the first permanent magnet 520 that protrudes away from the rotation axis Z1 of the rotor yoke 510 relative to the first reference circle 600 (i.e., the protrusion) matches the recesses 511. The side of the first permanent magnet 520 that faces away from the rotation axis Z1 of the rotor yoke 510 is accommodated in the recesses 511, and the protrusion is completely accommodated in the recesses 511. The twenty-second wall surface 523 is completely in contact with the rotor yoke 510, thereby facilitating the positioning and installation of the first permanent magnet 520 and facilitating a reduction in the outer diameter of the rotor yoke 510. The first permanent magnet 520 protruding from the twenty-second wall surface 523 is conducive to achieving a magnetic focusing effect.

[0145] Reference Figure 15 As shown, it can be understood that, in other embodiments, the portion of the first permanent magnet 520 that protrudes relative to the first reference circle 600 toward the rotation axis Z1 away from the rotor yoke 510 (i.e., the convex portion) and part of the structure of the remaining portion are accommodated in the recess 511, so that the two outer corners of the first permanent magnet 520 are both accommodated in the recess 511, and the sixteenth wall 521 and the seventeenth wall 522 of the first permanent magnet 520 respectively contact the two wall surfaces of the recess 511 that are arranged opposite to each other along the circumference of the rotor yoke 510, so that the rotor yoke 510 limits the first permanent magnet 520 in the circumferential direction, so that the first permanent magnet 520 is installed more firmly.

[0146] Reference Figure 12As shown, it can be understood that along the radial direction of the rotor yoke 510, at the recess 511, the rotor yoke 510 has a 20th wall surface 512 and a 21st wall surface 513 that are separated from each other, wherein the 20th wall surface 512 faces the rotation axis Z1 of the rotor yoke 510, and the 21st wall surface 513 faces away from the rotation axis Z1 of the rotor yoke 510. The 20th wall surface 512 is adapted to the 22nd wall surface 523, so that the 22nd wall surface 523 can be completely attached to the rotor yoke 510, facilitating positioning and installation. Along the radial direction of the rotor yoke 510, the minimum distance from the 20th wall surface 512 to the 21st wall surface 513 is defined as the minimum thickness T3 of the rotor yoke 510, and the maximum distance from the 20th wall surface 512 to the 21st wall surface 513 is defined as the maximum thickness T4 of the rotor yoke 510, satisfying the following: 0.1<T3 / T4<0.95. For example, T3 / T4=0.2, T3 / T4=0.3, T3 / T4=0.4, T3 / T4=0.5, T3 / T4=0.6, etc. Generally speaking, the inner diameter and outer diameter of the rotor yoke 510 are constant values, that is, T4 is a constant value. When T3 / T4 is too small, T3 is too small, that is, the minimum thickness of the rotor yoke 510 is too small. On the one hand, the strength of the rotor yoke 510 is insufficient, and on the other hand, the magnetic flux passing through the rotor yoke 510 at the location with the minimum thickness is easily saturated. As a result, the magnetic flux of the first permanent magnet 520 cannot be fully utilized, the air gap flux density is reduced, and it is not conducive to improving the output torque of the motor. When T3 / T4 is too large, T3 is too large, that is, the depth of the recess 511 along the radial direction of the rotor yoke 510 is too small, which is not conducive to the positioning and installation of the first permanent magnet 520. In addition, the twenty-second wall surface 523 may only partially fit the rotor yoke 510, which is not conducive to fully utilizing the magnetic flux and magnetic concentration of the first permanent magnet 520. Therefore, setting 0.1<T3 / T4<0.95 can both meet the strength requirements of the rotor yoke 510 and achieve a good magnetic concentration effect.

[0147] Reference Figure 11 As shown, it can be understood that the inner side of the first permanent magnet 520 is roughly tile-shaped, that is, the twenty-third wall surface 524 is at least partially an arcuate surface. Because sharp corners are prone to magnetic flux leakage, cutouts 527 are provided at both ends of the first permanent magnet 520 along the circumference of the rotor yoke 510. The cutouts 527 are located on the inner side of the first permanent magnet 520, that is, on the side of the first permanent magnet 520 that is closer to the rotation axis Z1 of the rotor yoke 510. In other words, the cutouts 527 are located at the inner corners of the first permanent magnet 520. Therefore, sharp corners on the inner side of the first permanent magnet 520 are avoided, which helps to reduce magnetic flux leakage.

[0148] Reference Figure 11 and Figure 13As shown, it can be understood that the first permanent magnet 520 forms a flat surface at the cutout 527, which is a portion of the twenty-third wall surface 524. On a projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510, the projection of the twenty-third wall surface 524 includes a second arc 525 and two straight line segments 526 located at the cutout 527, with the two straight line segments 526 respectively connecting the two ends of the second arc 525. The circle within which the second arc 525 lies is defined as a third reference circle 800, the center of which coincides with the rotation axis Z1 of the rotor yoke 510. Therefore, the twenty-third wall surface 524 can mate with the outer circumferential wall of the stator assembly, and the thickness of the air gap 560 corresponding to the second arc 525 is substantially uniform at all locations along the circumference of the rotor yoke 510. On the premise that the magnetic flux of the magnetic field of the first permanent magnet 520 is concentrated in the middle position of the first permanent magnet 520, the air gap magnetic flux distribution can be made closer to a sine waveform in space, thereby improving the output torque and efficiency of the motor and improving the running stability of the motor.

[0149] It can be understood that in other embodiments, on the projection surface perpendicular to the rotation axis Z1 of the rotor yoke 510, the projection of the twenty-third wall surface 524 only includes the second arc 525, and the center of the third reference circle 800 where the second arc 525 is located coincides with the rotation axis Z1 of the rotor yoke 510, which will not be repeated here.

[0150] Reference Figure 13 As shown, it can be understood that the two straight line segments 526 are symmetrically arranged about the symmetry center line of the first permanent magnet 520, and the straight line segments 526 are perpendicular to the symmetry center line of the first permanent magnet 520, thereby minimizing the sharp edges and corners on the inner side of the first permanent magnet 520 to minimize magnetic leakage.

[0151] It is easy to understand that in the prior art, since the two adjacent permanent magnets of the rotor assembly of the permanent magnet motor are attached to each other or separated from each other only by a magnetic isolation bridge, the permanent magnets have a serious problem of magnetic leakage, especially at the two ends of the permanent magnets along the circumference of the rotor assembly, the magnetic leakage problem is more serious. For example, at the end position of the permanent magnet, after the magnetic lines of force are emitted from the N pole, they are directly directed to the S pole of their own through the magnetic isolation bridge and form a closed-loop magnetic circuit, or the magnetic lines of force are directed from the N pole of the first permanent magnet through the magnetic isolation bridge to the S pole of the adjacent second permanent magnet, and from the N pole of the second permanent magnet through the magnetic isolation bridge to the S pole of the first permanent magnet, and form a closed-loop magnetic circuit, or the magnetic lines of force are directly directed from the N pole of the first permanent magnet to the S pole of the adjacent second permanent magnet, and from the N pole of the second permanent magnet directly to the S pole of the first permanent magnet, and form a closed-loop magnetic circuit. All of the above magnetic lines of force do not pass through the stator assembly, thereby forming magnetic leakage, affecting the magnetic field distribution and magnetic field strength between the rotor assembly and the stator assembly, and at the same time causing low utilization of the permanent magnets, affecting the performance of the motor.

[0152] For this purpose, refer to Figure 16 、 Figure 23 and Figure 24 As shown, it will be understood that in other embodiments, the rotor assembly 500 includes a plurality of main permanent magnets (i.e., the second permanent magnet 530 or the third permanent magnet 540) and a plurality of secondary permanent magnets (i.e., the fourth permanent magnet 550), and the number of the main permanent magnets is equal to the number of the secondary permanent magnets. In this embodiment, the rotor assembly 500 includes ten main permanent magnets and ten secondary permanent magnets. Specifically, the main permanent magnets and the secondary permanent magnets are both mounted on the inner periphery of the rotor yoke 510, that is, the main permanent magnets and the secondary permanent magnets are both located on the side of the rotor yoke 510 facing the stator assembly.

[0153] Reference Figure 16 As shown, it can be understood that multiple main permanent magnets are arranged at equal intervals along the circumference of the rotor yoke 510 on the inner circumference of the rotor yoke 510. The circumference of the rotor yoke 510 is the direction around the rotation axis Z1 of the rotor yoke 510. Each secondary permanent magnet is arranged between two adjacent main permanent magnets. The magnetization direction of the main permanent magnets is along the radial direction of the rotor yoke 510, and the magnetization directions of two adjacent main permanent magnets are opposite. The main permanent magnets serve as the magnetic poles of the rotor assembly 500. The magnetization direction of the secondary permanent magnets is along the tangential direction of the rotor yoke 510, and the magnetization directions of two adjacent secondary permanent magnets are opposite. At the same time, the magnetization direction of each secondary permanent magnet is the same as the direction of the magnetic field formed between the two adjacent main permanent magnets. The magnetization direction here refers to the direction of the magnetic field lines of the magnetic field formed by the corresponding permanent magnet, that is, the magnetization direction is the direction from the south pole through the interior of the permanent magnet to the north pole of the corresponding permanent magnet.

[0154] Reference Figure 16 and Figure 17 As shown, it can be understood that the main permanent magnet and the auxiliary permanent magnet can be bonded to the inner circumferential wall of the rotor yoke 510, or the main permanent magnet and the auxiliary permanent magnet can be installed in the installation groove provided on the inner circumferential wall of the rotor yoke 510.

[0155] The following describes in detail two adjacent main permanent magnets and the auxiliary permanent magnet therebetween as an example.

[0156] Reference Figure 16 As shown, it can be understood that two adjacent main permanent magnets are defined as the second permanent magnet 530 and the third permanent magnet 540 , and the auxiliary permanent magnet between the second permanent magnet 530 and the third permanent magnet 540 is defined as the fourth permanent magnet 550 .

[0157] It is understandable that the structures of the second permanent magnet 530 and the third permanent magnet 540 may be tile-shaped, or may have the same structure as the first permanent magnet 520 described above.

[0158] Reference Figure 16 and Figure 23 As shown, it can be understood that the inner side of the second permanent magnet 530 is an S pole and the outer side is an N pole, and the magnetization direction of the second permanent magnet 530 is from the S pole of the second permanent magnet 530 through the interior of the second permanent magnet 530 to the N pole of the second permanent magnet 530. The inner side of the third permanent magnet 540 is an N pole and the outer side is an S pole. The magnetization direction of the third permanent magnet 540 is from the S pole of the third permanent magnet 540 through the interior of the third permanent magnet 540 to the N pole of the third permanent magnet 540. The magnetization direction of the third permanent magnet 540 is opposite to that of the second permanent magnet 530. Therefore, under the action of the magnetic fields of the second permanent magnet 530 and the third permanent magnet 540, a magnetic field is formed between the rotor assembly 500 and the stator assembly. The direction of the magnetic lines of force of the magnetic field is from the N pole of the second permanent magnet 530 through the rotor yoke 510, the S pole of the third permanent magnet 540, the third permanent magnet 540, the N pole of the third permanent magnet 540, the air gap 560, the stator group, the air gap 560, the S pole of the second permanent magnet 530, the second permanent magnet 530 and back to the N pole of the second permanent magnet 530. The magnetic lines of force are a closed loop, and the magnetic field corresponding to the direction of the magnetic lines of force is the effective magnetic field of the motor.

[0159] Reference Figure 18 As shown, it can be understood that the second permanent magnet 530 has a symmetric centerline. Generally speaking, the second permanent magnet 530 has an axisymmetric structure. The second permanent magnet 530 is symmetrically arranged about its own symmetric centerline. The symmetric centerline of the second permanent magnet 530 intersects and is perpendicular to the rotation axis Z1 of the rotor yoke 510. The magnetization direction of the second permanent magnet 530 is parallel to the symmetric centerline of the second permanent magnet 530.

[0160] Reference Figure 25 As shown, in other embodiments, the opposite direction of the magnetization direction of the second permanent magnet 530 points to the rotation axis Z1, that is, the reverse extension line of the magnetization direction of the second permanent magnet 530 intersects with the rotation axis Z1.

[0161] Reference Figure 26 As shown, in other embodiments, the opposite direction of the magnetization direction of the second permanent magnet 530 points to the first reference point Q, wherein the first reference point Q is located on the symmetry center line of the second permanent magnet 530 and between the second permanent magnet 530 and the rotation axis Z1, that is, the reverse extension line of the magnetization direction of the second permanent magnet 530 intersects with the first reference point Q.

[0162] It is understandable that the magnetization direction of the third permanent magnet 540 can refer to the magnetization direction of the second permanent magnet 530, as long as the magnetization direction of the third permanent magnet 540 is opposite to the magnetization direction of the second permanent magnet 530, which will not be repeated here.

[0163] Reference Figure 16 As shown, it can be understood that the side of the fourth permanent magnet 550 facing the second permanent magnet 530 is the S pole, and the side facing the third permanent magnet 540 is the N pole, and the magnetization direction of the fourth permanent magnet 550 is from the S pole of the fourth permanent magnet 550 through the inside of the fourth permanent magnet 550 to the N pole of the fourth permanent magnet 550, that is, the magnetization direction of the fourth permanent magnet 550 is from the second permanent magnet 530 to the third permanent magnet 540 along the circumferential direction of the rotor yoke 510.

[0164] Therefore, under the action of the magnetic field of the fourth permanent magnet 550, the direction of the magnetic field lines of the leakage magnetic flux can be adjusted to point from the N pole of the second permanent magnet 530 to the S pole of the third permanent magnet 540, and will not directly return to the S pole of the second permanent magnet 530 through the rotor yoke 510 to form a closed loop, or will not return to the S pole of the second permanent magnet 530 through the third permanent magnet 540, the N pole of the third permanent magnet 540 and the rotor yoke 510 in sequence to form a closed loop, but will be connected to the effective magnetic field of the motor. The magnetic lines of force are aligned in direction and form a closed loop. Specifically, the magnetic field of the fourth permanent magnet 550 is used to enhance the guidance of the magnetic lines of force directed from the second permanent magnet 530 to the third permanent magnet 540. This allows the previously leaked magnetic lines of force to be added to the effective magnetic field of the motor, thereby reducing magnetic leakage from the circumferential ends of the second and third permanent magnets 530, 540 along the rotor yoke 510. This improves the utilization of the second and third permanent magnets 530, 540, and further enhances the effective magnetic field of the motor. Furthermore, the magnetic lines of force directed from the north pole of the second permanent magnet 530 to the south pole of the third permanent magnet 540 can pass through the fourth permanent magnet 550, which helps reduce the degree of magnetic circuit saturation in the rotor yoke 510, further improving the utilization of the second and third permanent magnets 530, 540, and enhancing the magnetic field, thereby improving the motor's torque, operating efficiency, and other performance.

[0165] Reference Figure 16 As shown, it can be understood that the fourth permanent magnet 550 has a symmetrical centerline. Generally speaking, the fourth permanent magnet 550 has an axisymmetric structure and is symmetrically arranged about the symmetrical centerline. The symmetrical centerline of the fourth permanent magnet 550 intersects and is perpendicular to the rotation axis Z1 of the rotor yoke 510. The magnetization direction of the fourth permanent magnet 550 is perpendicular to the symmetrical centerline of the fourth permanent magnet 550. Therefore, the magnetization direction of the fourth permanent magnet 550 is the same as and parallel to the direction of the magnetic field between the second permanent magnet 530 and the third permanent magnet 540. This further enhances the guidance of the magnetic field lines from the second permanent magnet 530 to the third permanent magnet 540, reduces magnetic leakage, and enhances the effective magnetic field of the motor.

[0166] Reference Figure 16 and Figure 18As shown, it can be understood that on a projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510, the projections of the second permanent magnet 530, the third permanent magnet 540, and the fourth permanent magnet 550 are all quadrilaterals. Along the radial direction of the rotor yoke 510, the second permanent magnet 530 has a twenty-sixth wall surface 531 and a twenty-seventh wall surface 532 that are spaced apart from each other. The twenty-sixth wall surface 531 faces the rotation axis Z1 of the rotor yoke 510, while the twenty-seventh wall surface 532 faces away from the rotation axis Z1 of the rotor yoke 510. The maximum distance between the twenty-sixth wall surface 531 and the twenty-seventh wall surface 532 is the maximum thickness T5 of the second permanent magnet 530. To measure T5, a vernier caliper can be used to directly clamp onto the twenty-sixth wall surface 531 and the second seventh wall surface 532 and measure the dimension at the position where the distance between the twenty-sixth wall surface 531 and the twenty-seventh wall surface 532 is the greatest.

[0167] Reference Figure 16 and Figure 19 As shown, it can be understood that along the radial direction of the rotor yoke 510, the third permanent magnet 540 has a 30th wall surface 541 and a 31st wall surface 542 that are separated from each other. The 30th wall surface 541 faces the rotation axis Z1 of the rotor yoke 510, and the 31st wall surface 542 faces away from the rotation axis Z1 of the rotor yoke 510. The maximum distance between the 30th wall surface 541 and the 31st wall surface 542 is the maximum thickness T6 of the third permanent magnet 540. To measure T6, a vernier caliper is used to directly clamp the 30th wall surface 541 and the 31st wall surface 542 and measure the dimension at the position where the distance between the 30th wall surface 541 and the 31st wall surface 542 is the greatest. Generally speaking, the outer shape of the second permanent magnet 530 is the same as that of the third permanent magnet 540, and T5 = T6.

[0168] Reference Figure 16 and Figure 20As shown, it can be understood that along the radial direction of the rotor yoke 510, the fourth permanent magnet 550 has a thirty-fourth wall surface 551 and a thirty-fifth wall surface 552 that are separated from each other. The thirty-fourth wall surface 551 faces the rotation axis Z1 of the rotor yoke 510, and the thirty-fifth wall surface 552 faces away from the rotation axis Z1 of the rotor yoke 510. The maximum distance between the thirty-fourth wall surface 551 and the thirty-fifth wall surface 552 is the maximum thickness T7 of the fourth permanent magnet 550. To measure T7, a vernier caliper is used to directly clamp the 34th wall surface 551 and the thirty-fifth wall surface 552 and measure the dimension at the position where the distance between the thirty-fourth wall surface 551 and the thirty-fifth wall surface 552 is the greatest. The following conditions are satisfied: T7>T5, T7>T6, that is, the maximum thickness of the fourth permanent magnet 550 is greater than the maximum thickness of the second permanent magnet 530, and the maximum thickness of the fourth permanent magnet 550 is greater than the maximum thickness of the third permanent magnet 540. Therefore, along the circumference of the rotor yoke 510, the two opposite wall surfaces of the fourth permanent magnet 550 can respectively cover the maximum thickness range of the second permanent magnet 530 and the third permanent magnet 540, thereby increasing the range of the fourth permanent magnet 550 guiding the magnetic lines of force from the second permanent magnet 530 to the third permanent magnet 540, which is beneficial to further reduce leakage magnetic flux and increase the effective magnetic field of the motor.

[0169] Reference Figure 16 and Figure 17 As shown, it can be understood that the rotor yoke 510 is provided with a fourth mounting slot 516. Specifically, the fourth mounting slot 516 is located on the side of the rotor yoke 510 facing the rotation axis Z1 of the rotor yoke 510. That is, the fourth mounting slot 516 is provided on the inner circumferential wall of the rotor yoke 510. The fourth mounting slot 516 penetrates the rotor yoke 510 along the direction of the rotation axis Z1 of the rotor yoke 510, and the opening of the fourth mounting slot 516 faces the rotation axis Z1 of the rotor yoke 510. The number of fourth mounting slots 516 is equal to the number of secondary permanent magnets. The end of the fourth permanent magnet 550 facing away from the rotation axis Z1 of the rotor yoke 510 is accommodated in the fourth mounting slot 516. That is, the fourth permanent magnet 550 is partially accommodated in the fourth mounting slot 516, while the end of the fourth permanent magnet 550 closer to the rotation axis Z1 of the rotor yoke 510 protrudes inward from the inner circumferential wall of the rotor yoke 510.

[0170] Reference Figure 16As shown, it can be understood that the second permanent magnet 530 and the third permanent magnet 540 respectively abut against the fourth permanent magnet 550 on both sides along the circumference of the rotor yoke 510. Therefore, in the entire rotor assembly 500, after a plurality of secondary permanent magnets (i.e., the fourth permanent magnet 550) are mounted on the rotor yoke 510, an installation space for mounting a main permanent magnet (i.e., the second permanent magnet 530 or the third permanent magnet 540) is formed between each two adjacent secondary permanent magnets (i.e., the fourth permanent magnet 550). The main permanent magnet is accommodated in this installation space, thereby simplifying the structure of the rotor yoke 510 and facilitating production. In addition, the main permanent magnets respectively abut against the two adjacent secondary permanent magnets on both sides along the circumference of the rotor yoke 510. Therefore, when assembling the rotor assembly 500, the secondary permanent magnet is first installed in the fourth mounting groove 516 of the rotor yoke 510, and the secondary permanent magnet is positioned through the fourth mounting groove 516. Then, the main permanent magnet is installed between the two adjacent secondary permanent magnets, and the main permanent magnet is positioned through the two adjacent secondary permanent magnets to facilitate assembly.

[0171] Reference Figure 16 As shown, it can be understood that along the circumference of the rotor yoke 510, the two ends of the thirty-fourth wall surface 551 are respectively butted against the twenty-sixth wall surface 531 and the thirtieth wall surface 541. That is, the twenty-sixth wall surface 531, the thirty-fourth wall surface 551, and the thirtieth wall surface 541 are sequentially butted together along the circumference of the rotor yoke 510, and form a portion of the inner circumferential wall of the rotor assembly 500. The wall surfaces of the plurality of main permanent magnets (i.e., the second permanent magnet 530 or the third permanent magnet 540) and the plurality of secondary permanent magnets (i.e., the fourth permanent magnet 550) facing the rotation axis Z1 of the rotor yoke 510 are sequentially butted together to form the inner circumferential wall of the rotor assembly 500, making the inner circumferential wall of the rotor assembly 500 a continuous wall surface, thereby ensuring the balance and stability of the rotor assembly 500 during rotation. Specifically, the twenty-sixth wall surface 531 , the thirtieth wall surface 541 and the thirty-fourth wall surface 551 may be planes. In this case, the projection of the inner circumferential wall of the rotor assembly 500 on the projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510 is a polygon.

[0172] Of course, in other embodiments, the twenty-sixth wall surface 531, the thirtieth wall surface 541 and the thirty-fourth wall surface 551 can be arc surfaces, and on the projection surface perpendicular to the rotation axis Z1 of the rotor yoke 510, the twenty-sixth wall surface 531, the thirtieth wall surface 541 and the thirty-fourth wall surface 551 are on the same reference circle with the center located on the rotation axis Z1 of the rotor yoke 510. Therefore, on the projection surface perpendicular to the rotation axis Z1Z of the rotor yoke 510, the projection of the inner circumferential wall of the rotor assembly 500 is a circle.

[0173] Therefore, T7>T5, T7>T6 are satisfied, so that the fourth permanent magnet 550 can be pre-installed in the rotor yoke 510, and the fourth permanent magnet 550 is used as the positioning and installation reference for the second permanent magnet 530 and the third permanent magnet 540, which facilitates the installation of the second permanent magnet 530 and the third permanent magnet 540, that is, the secondary permanent magnet is used as the positioning and installation reference for the main permanent magnet; at the same time, after the main permanent magnet and the secondary permanent magnet are installed, the inner circumferential wall of the rotor assembly 500 can be made into a continuous wall surface to ensure the balance and stability of the rotor assembly 500 during rotation.

[0174] Reference Figure 21 and Figure 22 As shown, it will be understood that in other embodiments, the rotor yoke 510 is provided with a second mounting groove 514, a third mounting groove 515, and a fourth mounting groove 516. The second mounting groove 514, the third mounting groove 515, and the fourth mounting groove 516 are all provided on the inner circumferential wall of the rotor yoke 510, and the second mounting groove 514, the fourth mounting groove 516, and the third mounting groove 515 are sequentially spaced apart along the circumferential direction of the rotor yoke 510. Similarly, the second mounting groove 514, the third mounting groove 515, and the fourth mounting groove 516 all penetrate the rotor yoke 510 in the direction of the rotation axis Z1 of the rotor yoke 510, and the openings of the second mounting groove 514, the third mounting groove 515, and the fourth mounting groove 516 all face the rotation axis Z1 of the rotor yoke 510. The number of second mounting slots 514 is equal to the number of third mounting slots 515, and the sum of the number of second mounting slots 514 and the number of third mounting slots 515 is equal to the number of main permanent magnets. The number of fourth mounting slots 516 is equal to the number of secondary permanent magnets. The second permanent magnet 530 is accommodated in the second mounting slot 514, the third permanent magnet 540 is accommodated in the third mounting slot 515, and the fourth permanent magnet 550 is accommodated in the fourth mounting slot 516. Therefore, in the entire rotor assembly 500, the secondary permanent magnet is installed in the fourth mounting slot 516, and the main permanent magnet is installed in the second mounting slot 514 and the third mounting slot 515, respectively. When assembling the rotor assembly 500, the main permanent magnet is positioned by the second mounting slot 514 and the third mounting slot 515, while the secondary permanent magnet is positioned by the fourth mounting slot 516. In other words, the installation and positioning of the main permanent magnet and the secondary permanent magnet are independent of each other, which helps simplify the assembly process and reduce assembly errors.

[0175] Reference Figure 21 and Figure 22As shown, it can be understood that because the second mounting slot 514, the fourth mounting slot 516, and the third mounting slot 515 are sequentially spaced along the circumference of the rotor yoke 510, the rotor yoke 510 is formed with a first insulating portion 517 and a second insulating portion 518. The first insulating portion 517 is formed between the second mounting slot 514 and the fourth mounting slot 516, and the second insulating portion 518 is formed between the third mounting slot 515 and the fourth mounting slot 516. Throughout the rotor yoke 510, the number of first insulating portions 517 and the number of second insulating portions 518 are equal, and the number of first insulating portions 517 and the number of fourth mounting slots 516 are equal. The first insulating portion 517 has a twenty-fourth wall surface 5171 facing the rotation axis Z1 of the rotor yoke 510, and the second insulating portion 518 has a twenty-fifth wall surface 5181 facing the rotation axis Z1 of the rotor yoke 510. The twenty-sixth wall surface 531, the twenty-fourth wall surface 5171, the thirty-fourth wall surface 551, the twenty-fifth wall surface 5181, and the thirtieth wall surface 541 are sequentially butted together along the circumference of the rotor yoke 510, and form a portion of the inner circumferential wall of the rotor assembly 500. The wall surfaces of the plurality of main permanent magnets (i.e., the second permanent magnet 530 or the third permanent magnet 540), the plurality of secondary permanent magnets (i.e., the fourth permanent magnet 550), the plurality of first partitions 517, and the plurality of second partitions 518 facing the rotation axis Z1 of the rotor yoke 510 are sequentially butted together to form the inner circumferential wall of the rotor assembly 500, making the inner circumferential wall of the rotor assembly 500 a continuous wall surface, thereby ensuring the balance and stability of the rotor assembly 500 during rotation.

[0176] Reference Figure 21 As shown, it can be understood that the twenty-sixth wall surface 531, the thirtieth wall surface 541, the thirty-fourth wall surface 551, the twenty-fourth wall surface 5171, and the twenty-fifth wall surface 5181 are all arcuate surfaces. On a projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510, the projections of the twenty-sixth wall surface 531, the thirtieth wall surface 541, the thirty-fourth wall surface 551, the twenty-fourth wall surface 5171, and the twenty-fifth wall surface 5181 form a fourth reference circle 900, and the center of the fourth reference circle 900 coincides with the rotation axis Z1 of the rotor yoke 510. Therefore, on the projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510, the projection of the inner circumferential wall of the rotor assembly 500 is circular.

[0177] Of course, in other embodiments, the twenty-sixth wall 531, the thirtieth wall 541, the thirty-fourth wall 551, the twenty-fourth wall 5171 and the twenty-fifth wall 5181 can be planes. In this case, on the projection plane perpendicular to the rotation axis Z1 of the rotor yoke 510, the projection of the inner circumferential wall of the rotor assembly 500 is a polygon.

[0178] Reference Figure 17 and Figure 22As shown, it can be understood that along the circumference of the rotor yoke 510, the second mounting groove 514 has a first width W 11 , the first width W 11 That is, the distance between the two groove walls of the second mounting groove 514 arranged opposite to each other along the circumferential direction of the rotor yoke 510. Similarly, the third mounting groove 515 has a second width W 12 , the second width W 12 That is, the distance between two groove walls of the third mounting groove 515 arranged opposite to each other along the circumferential direction of the rotor yoke 510, and the fourth mounting groove 516 has a third width W 13 , the third width W 13 That is, the distance between two groove walls of the fourth mounting groove 516 arranged opposite to each other along the circumferential direction of the rotor yoke 510. Along the radial direction of the rotor yoke 510 and toward the rotation axis Z1 of the rotor yoke 510, that is, from the outside to the inside of the rotor yoke 510, the first width W 11 , the second width W 12 and the third width W 13 That is, the width of the second mounting groove 514 at the slot opening is smaller than the width at the slot bottom. Similarly, the width of the third mounting groove 515 at the slot opening is smaller than the width at the slot bottom. The width of the fourth mounting groove 516 at the slot opening is smaller than the width at the slot bottom. Therefore, when installing the second permanent magnet 530, the third permanent magnet 540 and the fourth permanent magnet 550, the second permanent magnet 530 is inserted into the second mounting groove 514 along the direction of the rotation axis Z1 of the rotor yoke 510, the third permanent magnet 540 is inserted into the third mounting groove 515 along the direction of the rotation axis Z1 of the rotor yoke 510, and the fourth permanent magnet 550 is inserted into the fourth mounting groove 516 along the direction of the rotation axis Z1 of the rotor yoke 510. Thus, the second mounting groove 514 can limit the second permanent magnet 530 from detaching from the rotor yoke 510 toward the inner side of the rotor yoke 510 and prevent ...40 from detaching from the rotor yoke 510. The magnet 530 is loose. Similarly, the third mounting groove 515 can limit the third permanent magnet 540 from detaching from the rotor yoke 510 toward the inner side of the rotor yoke 510, and the fourth mounting groove 516 can limit the fourth permanent magnet 550 from detaching from the rotor yoke 510 toward the inner side of the rotor yoke 510, and can prevent the third permanent magnet 540 and the fourth permanent magnet 550 from loosening, thereby improving the installation stability of the second permanent magnet 530, the third permanent magnet 540 and the fourth permanent magnet 550, that is, improving the installation stability of the main permanent magnet and the auxiliary permanent magnet, ensuring the stability of the rotor assembly 500 during rotation and helping to reduce noise.

[0179] Reference Figure 18 As shown, it can be understood that, along the circumference of the rotor yoke 510, the second permanent magnet 530 has a twenty-eighth wall surface 533 and a twenty-ninth wall surface 534 that are separated from each other, and the maximum distance between the twenty-eighth wall surface 533 and the twenty-ninth wall surface 534 is W 14, that is, the maximum width of the second permanent magnet 530 is W 14 , measure W 14 When the second permanent magnet 530 is sized, a vernier caliper is used to directly clamp the 28th wall 533 and the 29th wall 534 and measure the size of the position where the distance between the 28th wall 533 and the 29th wall 534 is the largest. 14 It is the distance from the intersection of the twenty-eighth wall surface 533 and the twenty-seventh wall surface 532 to the intersection of the twenty-ninth wall surface 534 and the twenty-seventh wall surface 532 .

[0180] Reference Figure 19 As shown, it can be understood that, along the circumference of the rotor yoke 510, the third permanent magnet 540 has a thirty-second wall surface 543 and a thirty-third wall surface 544 that are opposite to each other, and the maximum distance between the thirty-second wall surface 543 and the thirty-third wall surface 544 is W 15 , that is, the maximum width of the third permanent magnet 540 is W 15 , measure W 15 When the third permanent magnet 540 is sized, a vernier caliper is used to directly clamp the 32nd wall 543 and the 33rd wall 544 and measure the size of the position where the distance between the 32nd wall 543 and the 33rd wall 544 is the largest. 15 is the distance from the intersection of the 32nd wall surface 543 and the 31st wall surface 542 to the intersection of the 33rd wall surface 544 and the 31st wall surface 542. 14 =W 15 .

[0181] Reference Figure 20 As shown, it can be understood that, along the circumference of the rotor yoke 510, the fourth permanent magnet 550 has a thirty-sixth wall 553 and a thirty-seventh wall 554 that are separated from each other, and the maximum distance between the thirty-sixth wall 553 and the thirty-seventh wall 554 is W 16 , that is, the maximum width of the fourth permanent magnet 550 is W 16 , measure W 16 When the fourth permanent magnet 550 is sized, a vernier caliper is used to directly measure the size of the position where the distance between the 36th wall 553 and the 37th wall 554 is the largest. 16 It is the distance from the intersection of the thirty-sixth wall surface 553 and the thirty-fifth wall surface 552 to the intersection of the thirty-seventh wall surface 554 and the thirty-fifth wall surface 552 .

[0182] Reference Figures 18 to 20 As shown, it can be understood that the maximum width W of the second permanent magnet 530 14, the maximum width W of the third permanent magnet 540 15 and the maximum width W of the fourth permanent magnet 550 16 Satisfaction: W 16 <W 14 , W 16 <W 15 That is, the maximum width of the fourth permanent magnet 550 is smaller than the maximum width of the second permanent magnet 530, and the maximum width of the fourth permanent magnet 550 is smaller than the maximum width of the third permanent magnet 540, so that the width of the fourth permanent magnet 550 is smaller. That is, a secondary permanent magnet with a smaller width is used to reduce the space occupied by the secondary permanent magnet, thereby increasing the installation space of the main permanent magnet, so as to increase the width of the main permanent magnet, enhance the strength of the effective magnetic field, and increase the torque of the motor.

[0183] The motor according to the second embodiment of the present invention includes a rotor assembly 500 and the stator assembly according to the first embodiment of the present invention. The rotor assembly 500 is wound around the outer circumference of the stator assembly and will not be described in detail here.

[0184] Since the motor adopts all the technical solutions of the stator assembly of the above embodiment, it has at least all the beneficial effects brought about by the technical solutions of the above embodiment.

[0185] The electrical equipment of the third embodiment of the present invention includes the motor of the second embodiment of the present invention. The electrical equipment can be a fan, an air-conditioning compressor, a refrigerator compressor, a drum washing machine, etc.

[0186] Since the electrical device adopts all the technical solutions of the motor of the above embodiment, it has at least all the beneficial effects brought about by the technical solutions of the above embodiment.

[0187] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the scope of the present invention.

Claims

1. Stator assembly, characterized in that, include: stator yoke; a plurality of first stator teeth, each of the first stator teeth comprising a first tooth portion and a first tooth top, one end of the first tooth portion being connected to the stator yoke, the first tooth top being connected to the other end of the first tooth portion, the first tooth portion having a first wall surface and a second wall surface facing away from each other along the circumference of the stator yoke, the minimum distance between the first wall surface and the second wall surface being W1, the first tooth top having a third wall surface and a fourth wall surface facing away from each other, the minimum distance between an end of the third wall surface facing away from the stator yoke and an end of the fourth wall surface facing away from the stator yoke being W2; a plurality of second stator teeth, each of the second stator teeth comprising a second tooth portion and a second tooth top, one end of the second tooth portion being connected to the stator yoke, the second tooth top being connected to the other end of the second tooth portion, the second tooth portion having a fifth wall surface and a sixth wall surface facing away from each other along the circumferential direction, the minimum distance between the fifth wall surface and the sixth wall surface being W3, the second tooth top having a seventh wall surface and an eighth wall surface facing away from each other, the minimum distance between an end of the seventh wall surface facing away from the stator yoke and an end of the eighth wall surface facing away from the stator yoke being W4; The plurality of first stator teeth and the plurality of second stator teeth are alternately arranged along the circumferential direction on the outer periphery of the stator yoke, the minimum distance between two adjacent first tooth tops is L1, and the minimum distance between adjacent first tooth tops and second tooth tops is L2, satisfying the following conditions: 10 < (L1 / L2) * (W1 / W3) * (W2 / W4) < 40, W1 > W3, W2 > W4; Along the circumferential direction, the first tooth top protrudes toward both sides of the first tooth portion, and a first groove is provided on at least one side of the first tooth top protruding from the first tooth portion, and a notch of the first groove faces away from the stator yoke portion.

2. The stator assembly according to claim 1, characterized in that: The stator assembly further includes a winding, and the winding is wound around the first tooth portion.

3. The stator assembly according to claim 2, characterized in that: The second tooth portion is detachably connected to the stator yoke portion.

4. The stator assembly according to claim 3, characterized in that: The second tooth portion includes a mounting portion, the stator yoke portion is provided with a first mounting groove, the opening of the first mounting groove faces the second tooth top, and the mounting portion is accommodated in the first mounting groove.

5. The stator assembly according to claim 4, characterized in that: Along the circumferential direction, the first mounting groove has a ninth wall surface and a tenth wall surface arranged opposite to each other. In the radial direction perpendicular to the stator yoke, the distance between the ninth wall surface and the tenth wall surface is the width of the first mounting groove. The first mounting groove includes a first slot section, and the first slot section is located at one end of the first mounting groove close to the central axis of the stator yoke part. The width of the first slot section decreases from the stator yoke part toward the second tooth top.

6. The stator assembly according to claim 5, characterized in that: The first mounting slot includes a second slot segment, which is located at one end of the first slot segment close to the second tooth top. The width of the second slot segment increases gradually from the stator yoke toward the second tooth top.

7. The stator assembly according to claim 5, characterized in that: Along the circumferential direction, the maximum width of the first installation groove is Y1, and the minimum width of the first installation groove is Y2, satisfying: 1<Y1 / Y2<3.

8. The stator assembly according to claim 4, characterized in that: Along the radial direction of the stator yoke, the stator yoke has an eleventh wall and a twelfth wall facing away from each other, the eleventh wall is closer to the central axis of the stator yoke than the twelfth wall, the first mounting groove has a thirteenth wall facing away from the eleventh wall, the minimum distance between the eleventh wall and the twelfth wall is W5, and the minimum distance between the thirteenth wall and the eleventh wall is W6, satisfying: 0.2<(W5-W6) / W5<0.

8.

9. The motor is characterized in that include: The stator assembly according to any one of claims 1 to 8; The rotor assembly is wound around the outer circumference of the stator assembly.

10. The motor according to claim 9, characterized in that: The maximum outer diameter of the rotor assembly is D1, and the minimum inner diameter of the rotor assembly is D2, satisfying: 0.8<(W1 / W3)*(D2 / D1)<1.

9.

11. The motor according to claim 9, characterized in that: The maximum outer diameter of the rotor assembly is D1, and the minimum inner diameter of the rotor assembly is D2, satisfying: 1.4<(W2 / W4)*(D2 / D1)<3.

2.

12. The motor according to claim 9, characterized in that: The rotor assembly rotates forwardly along a first direction, and the first groove is located at a rear end of the first stator tooth along the first direction.

13. The motor according to claim 12, characterized in that: The first tooth top has a fourteenth wall surface and a fifteenth wall surface on a side facing away from the first tooth portion. The fourteenth wall surface and the fifteenth wall surface are sequentially arranged along the first direction and are respectively located on both sides of the first groove. The minimum distance between the two ends of the fifteenth wall surface along the circumferential direction is W7. The rotor assembly includes a rotor yoke and a plurality of first permanent magnets. The plurality of first permanent magnets are arranged on the inner circumference of the rotor yoke and spaced apart along the circumferential direction. The maximum distance between two wall surfaces of the first permanent magnets facing away from each other along the circumferential direction is W8. The maximum outer diameter of the rotor assembly is D1, and the minimum inner diameter of the rotor assembly is D2, satisfying: 0.6<(W7 / W8)*(D2 / D1)<1.

11.

14. The motor according to claim 13, characterized in that: Along the circumferential direction, the minimum distance between the first grooves at the notch is W9, and the minimum distance between the two opposite walls of two adjacent first permanent magnets is W 10 , satisfying: 0.5<W9 / W 10 <2.

15. The motor according to claim 9, characterized in that: The first tooth top is provided with the first groove on one side thereof. The first tooth top is also provided with a second groove. The second groove is located on the other side of the first tooth portion, and the notch of the second groove faces the rotor assembly.

16. The motor according to claim 15, characterized in that: The first stator tooth has a symmetry center line arranged along a radial direction of the stator yoke, and the second groove is arranged symmetrically to the first groove about the symmetry center line.

17. Electrical equipment, characterized in that Comprising a motor as claimed in any one of claims 9 to 16.

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