Stator laminations, stator cores and permanent magnet motors

Abstract

The present application provides a stator punching sheet, a stator core, and a permanent magnet motor. The stator punching sheet comprises a yoke (1), a tooth portion (2), and a tooth shoe (3) arranged on a side of the tooth portion (2) away from the yoke (1). The tooth portion (2) is evenly distributed along the circumference of the yoke (1). Auxiliary slots (4) are provided on the inner peripheral walls of at least some of the tooth shoes (3), and the structures of the inner peripheral walls of at least two adjacent tooth shoes (3) are different. According to the stator punching sheet of the present application, a stator core with skew slots can be formed by using the stator punching sheet, so as to realize the combination of the skew slots and the auxiliary slots and effectively reduce torque pulsation.

Description

Technical Field

[0001] The present application relates to the technical field of motor equipment, and in particular to a stator punching sheet, a stator core and a permanent magnet motor. Background Art

[0002] Permanent magnet motors are widely used due to their high efficiency and high power density. However, the electromagnetic torque output by the motor contains certain pulsations, which can lead to poor quality of the output torque and cause vibration in the motor.

[0003] Prior art uses stator skew slots to reduce torque ripple peaks and stator vibration. However, this structure is complex, has low production efficiency, and is costly. Another prior art approach is to create auxiliary slots in the stator teeth to increase the order of tooth harmonics and reduce vibration caused by low-order harmonics. However, this approach only provides limited torque ripple reduction and is ineffective. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present application is to provide a stator punching sheet, a stator core and a permanent magnet motor, which can use the stator punching sheet to form a skewed slot stator core, realize the combination of the skew slot and the auxiliary slot, and effectively reduce the torque pulsation.

[0005] In order to solve the above problems, the present application provides a stator punching sheet, including a yoke, a tooth portion and a tooth shoe arranged on the side of the tooth portion away from the yoke, the teeth are evenly distributed along the circumference of the yoke, and auxiliary grooves are provided on the inner circumferential wall of at least part of the tooth shoe, and the structures of the inner circumferential walls of at least two adjacent tooth shoes are different.

[0006] Preferably, auxiliary grooves are provided on the inner circumferential walls of at least two adjacent tooth shoes, and the auxiliary grooves on the inner circumferential walls of the two adjacent tooth shoes have the same structure.

[0007] Preferably, the auxiliary grooves on the inner peripheral walls of two adjacent tooth shoes have the same structure but different numbers.

[0008] Preferably, the auxiliary grooves on the inner peripheral walls of two adjacent tooth shoes have the same structure and number, and at least some of the auxiliary grooves are located at different positions.

[0009] Preferably, auxiliary grooves are provided on the inner circumferential walls of at least two adjacent tooth shoes, and the structures of the auxiliary grooves on the inner circumferential walls of the two adjacent tooth shoes are different.

[0010] Preferably, the number of tooth shoes of the stator punching sheet is z, and 2 n ≤z<2 n+1 , then one of the tooth shoes is used as the initial tooth shoe, and the initial tooth shoe is not provided with an auxiliary groove. Starting from the initial tooth shoe, along the rotation direction of the motor rotor, in the continuous 2 n - Each tooth shoe is provided with an auxiliary groove.

[0011] Preferably, n is the total number of setting positions of the auxiliary slot on a single tooth shoe. When the auxiliary slot is set at a setting position on the tooth shoe, the setting position is marked as 1. When the auxiliary slot is not set at a setting position, the setting position is marked as 0. On any tooth shoe, along the rotation direction of the motor rotor, the binary digits of the setting position are arranged from low to high. In the continuous 2 n -1 tooth shoe, in order from small to large, the auxiliary grooves are arranged in binary manner on each tooth shoe.

[0012] Preferably, the number of tooth boots is 9, wherein no auxiliary slots are set on the initial tooth boot and the last tooth boot. Along the rotation direction of the motor rotor, the initial tooth boot is the first tooth boot, the last tooth boot is the ninth tooth boot, the binary number formed by the auxiliary slots on the second tooth boot is 001, the binary number formed by the auxiliary slots on the third tooth boot is 010, the binary number formed by the auxiliary slots on the fourth tooth boot is 011, the binary number formed by the auxiliary slots on the fifth tooth boot is 100, the binary number formed by the auxiliary slots on the sixth tooth boot is 101, the binary number formed by the auxiliary slots on the seventh tooth boot is 110, and the binary number formed by the auxiliary slots on the eighth tooth boot is 111.

[0013] Preferably, there are three auxiliary slots. In the cross section perpendicular to the central axis of the stator punching sheet, when the auxiliary slot is set at the setting position with the lowest number of positions, the angle between the line connecting the center of the slot bottom of the auxiliary slot and the center of the stator punching sheet and the center line of the tooth shoe where the auxiliary slot is located is b, b = (1 / 5~1 / 3)*a; when the auxiliary slot is set at the middle setting position, the auxiliary slot is located on the center line of the tooth shoe where it is located; when the auxiliary slot is set at the setting position with the highest number of positions, the angle between the line connecting the center of the slot bottom of the auxiliary slot and the center of the stator punching sheet and the center line of the tooth shoe where the auxiliary slot is located is c, c = (1 / 5~1 / 3)*a, where a is the tooth pole angle, a = 360 / z.

[0014] Preferably, the number of tooth shoes is 9, and three auxiliary slots are provided on one of the tooth shoes. In the cross section perpendicular to the central axis of the stator punching sheet, the auxiliary slots located on both sides of the circumference are symmetrical about the center line of the tooth shoe, and the auxiliary slot located in the middle is located on the center line of the tooth shoe.

[0015] Preferably, the auxiliary groove has a width of 1.4 mm and a depth of 0.7 mm.

[0016] Preferably, the width of the auxiliary slot is L2, and the width of the stator slot is L1, wherein L2 = (1 / 3 to 4 / 3) * L1.

[0017] Preferably, the cross section of the auxiliary groove is semicircular, square or triangular.

[0018] According to another aspect of the present application, a stator core is provided, comprising the above-mentioned stator punchings, wherein a plurality of stator punchings are stacked into axial segments, the number of stator punchings being zt, where z is the number of tooth boots of each stator punching, and t is the number of stator punchings in each axial segment, where t is a positive integer, and starting from the second stator punching axial segment, each stator punching axial segment is rotated by a tooth pole angle a relative to the previous stator punching axial segment, wherein the tooth pole angle a=360 / z.

[0019] According to another aspect of the present application, a permanent magnet motor is provided, comprising a stator core, which is the stator core described above.

[0020] Preferably, the permanent magnet motor further includes a motor rotor, which is arranged on the inner circumference of the stator core and forms an air gap with the stator core. The thickness of the air gap is H1, and the depth of the auxiliary slot is H2, where H2 = (1 / 2 to 3 / 2) * H1.

[0021] Preferably, the permanent magnet motor further includes a motor rotor, which is arranged on the inner circumference of the stator core and forms an air gap with the stator core. The thickness of the air gap is 0.8 mm, and the slot width of the stator core is 3.2 mm.

[0022] The stator punching provided in the present application includes a yoke, a tooth portion, and a tooth shoe disposed on a side of the tooth portion away from the yoke. The teeth are evenly distributed along the circumference of the yoke. Auxiliary slots are disposed on the inner circumferential walls of at least some of the tooth shoes, and the inner circumferential walls of at least two adjacent tooth shoes have different structures. When the stator punching is used to form a stator core, the stator punching can be rotated sequentially by an angle in the same direction during the lamination process, so that the final stator core can have the effect of stator skew slots. At the same time, because the auxiliary slots are disposed on the inner circumferential walls of at least some of the tooth shoes, and the inner circumferential walls of at least two adjacent tooth shoes have different structures, the auxiliary slots will also rotate during the rotation of the stator punching. Therefore, only one type of punching is required to form auxiliary slots on each tooth shoe of the final stator core, which simplifies the process. The auxiliary slots can be used to increase the tooth harmonic order, so that the stator punching can be used to form a skewed slot stator core. The auxiliary slots on the stator punching enable the final stator core to achieve a combination of skew slots and auxiliary slots, effectively reducing torque pulsation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the three-dimensional structure of a stator punching sheet according to an embodiment of the present application;

[0024] Figure 2 This is a schematic diagram of the first structure of the stator punching sheet according to an embodiment of the present application;

[0025] Figure 3 This is a schematic diagram of the second structure of the stator punching sheet according to an embodiment of the present application;

[0026] Figure 4 This is a schematic diagram of the third structure of the stator punching sheet according to an embodiment of the present application;

[0027] Figure 5 Schematic diagram of the three-dimensional structure of the stator core of an embodiment of the present application;

[0028] Figure 6 This is a structural dimension diagram of the stator core and the motor rotor in accordance with an embodiment of the present application;

[0029] Figure 7 A comparison diagram of the cogging torque between the permanent magnet motor of the embodiment of the present application and the motor in the prior art;

[0030] Figure 8 A comparison diagram of the output torque of the permanent magnet motor of the embodiment of the present application and the motor in the prior art;

[0031] Figure 9 Schematic diagram of the matching structure of the motor rotor and the stator assembly of the permanent magnet motor of an embodiment of the present application at different rotation positions.

[0032] The reference numerals indicate:

[0033] 1. Yoke; 2. Tooth; 3. Tooth shoe; 4. Auxiliary slot; 5. Motor rotor. DETAILED DESCRIPTION

[0034] See also Figures 1 to 9 As shown, according to an embodiment of the present application, the stator punching sheet includes a yoke 1, a tooth portion 2 and a tooth shoe 3 arranged on the side of the tooth portion 2 away from the yoke 1, the tooth portion 2 is evenly distributed along the circumference of the yoke 1, and auxiliary grooves 4 are provided on the inner circumferential wall of at least part of the tooth shoe 3, and the structures of the inner circumferential walls of at least two adjacent tooth shoes 3 are different.

[0035] When the stator punching sheets are used to form the stator core, the stator punching sheets can be rotated in the same direction by an angle in sequence during the stacking process, so that the final stator core can have the effect of stator skew slots. At the same time, since auxiliary slots 4 are provided on the inner circumferential walls of at least part of the tooth shoes 3, the structures of the inner circumferential walls of at least two adjacent tooth shoes 3 are different. Therefore, during the rotation of the stator punching sheets, the auxiliary slots 4 will also rotate accordingly. Therefore, only one type of punching sheet is needed to form auxiliary slots 4 on each tooth shoe 3 of the final stator core, and the auxiliary slots 4 located on the same axis of the inner circumferential wall of the stator core have different structures from the adjacent auxiliary slots 4. The process is simpler, and the auxiliary slots 4 can be used to improve the tooth harmonic order, so that the stator punching sheets can be used to form a skew slot stator core. The auxiliary slots 4 on the stator punching sheets can enable the final stator core to achieve the combination of skew slots and auxiliary slots 4, effectively reducing torque pulsation.

[0036] An auxiliary groove 4 is provided on the inner circumferential walls of at least two adjacent tooth shoes 3 , and the auxiliary grooves 4 on the inner circumferential walls of the two adjacent tooth shoes 3 have the same structure.

[0037] Specifically, in one embodiment, the auxiliary grooves 4 on the inner circumferential walls of two adjacent tooth shoes 3 have the same structure but different numbers. For example, one tooth shoe 3 may have one auxiliary groove 4, while the other tooth shoe 3 may have two or three auxiliary grooves 4. Of the auxiliary grooves 4 on the other tooth shoe 3, one may be located at the same position on the tooth shoe as the auxiliary groove 4 on the first tooth shoe 3, or all of the auxiliary grooves 4 may be located at different positions on the tooth shoe than the auxiliary grooves 4 on the first tooth shoe 3.

[0038] In another embodiment, the auxiliary grooves 4 on the inner circumferential walls of two adjacent tooth shoes 3 have the same structure and number, but the positions of at least some of the auxiliary grooves 4 are different. For example, the first tooth shoe 3 is provided with an auxiliary groove 4 located on the left side of the tooth shoe 3, and the second tooth shoe 3 is also provided with an auxiliary groove 4 located on the right side or in the middle of the second tooth shoe 3.

[0039] In another embodiment not shown in the figures, auxiliary grooves 4 are provided on the inner circumferential walls of at least two adjacent tooth shoes 3 , and the structures of the auxiliary grooves 4 on the inner circumferential walls of the two adjacent tooth shoes 3 are different.

[0040] The number of tooth shoes 3 of the stator punching is z, and 2 n ≤z<2 n+1 , then one of the tooth shoes 3 is used as the initial tooth shoe 3, and the initial tooth shoe 3 is not provided with an auxiliary groove 4. Starting from the initial tooth shoe 3, along the rotation direction of the motor rotor 5, in the continuous 2 n -1 tooth shoe 3 is provided with auxiliary slots 4, and the number or position of the auxiliary slots 4 on at least two adjacent tooth shoes 3 are different, so that the adjacent tooth shoes 3 form different tooth shoe structures. For example, when the number of tooth shoes 3 of the stator punching is 6, then 2 2 ≤z<2 2+1 Therefore, no auxiliary groove 4 is provided on the initial tooth shoe 3. Starting from the initial tooth shoe 3, auxiliary grooves 4 are provided on 4-1=3 consecutive tooth shoes 3 along the rotation direction of the motor rotor 5. For the fifth and sixth tooth shoes 3, the same structure as the initial tooth shoe is adopted, that is, no auxiliary groove 4 is provided on the tooth shoe 3.

[0041] Preferably, n is the total number of setting positions of the auxiliary slot 4 on a single tooth shoe 3. When the auxiliary slot 4 is set at a setting position on the tooth shoe 3, the setting position is marked as 1. When the auxiliary slot 4 is not set at a setting position, the setting position is marked as 0. On any tooth shoe 3, along the rotation direction of the motor rotor 5, the binary digits of the setting position are arranged from low to high. In the continuous 2 n -1 tooth shoe 3, the auxiliary slots 4 are arranged in binary order on each tooth shoe 3 in ascending order. In this embodiment, the total number of arrangement positions refers to the number of arrangement positions of the auxiliary slots 4 on the tooth shoe after all the tooth shoes on the same stator punching are overlapped. When the number of tooth shoes 3 on the stator punching is determined, the number of arrangement positions of the auxiliary slots 4 on the tooth shoe is also determined accordingly.

[0042] Through this arrangement, in each section of the iron core, the number of slots on each tooth increases successively along the direction of rotation of the rotor, and the positions of the slots shift successively toward the direction of rotation. Along the direction of rotation, the magnitude and direction of the electromagnetic force acting on each tooth change evenly, thereby reducing the number of torque mutations and making the torque more stable.

[0043] like Figure 9 As shown, taking stator tooth 1 at the 12 o'clock position as an example, the stator teeth are numbered 1 to 9 in a clockwise direction. In position 1, the rotor poles directly face stator teeth 1, 4, and 7, where the electromagnetic force is greatest. The total number of auxiliary slots is 3. In position 3, the rotor poles directly face stator teeth 2, 5, and 8, for a total of 4 auxiliary slots. In position 2, the rotor poles directly face stator teeth 3, 6, and 9, for a total of 5 auxiliary slots. As the rotor rotates, its position changes periodically between positions 1, 2, and 3, and the torque changes smoothly.

[0044] In this embodiment, the number of tooth shoes 3 is 9, wherein the auxiliary slots 4 are not provided on the initial tooth shoe 3 and the last tooth shoe 3. Along the rotation direction of the motor rotor 5, the initial tooth shoe 3 is the first tooth shoe, the last tooth shoe 3 is the ninth tooth shoe, the binary number formed by the auxiliary slots 4 on the second tooth shoe is 001, the binary number formed by the auxiliary slots 4 on the third tooth shoe is 010, the binary number formed by the auxiliary slots 4 on the fourth tooth shoe is 011, the binary number formed by the auxiliary slots 4 on the fifth tooth shoe is 100, the binary number formed by the auxiliary slots 4 on the sixth tooth shoe is 101, the binary number formed by the auxiliary slots 4 on the seventh tooth shoe is 110, and the binary number formed by the auxiliary slots 4 on the eighth tooth shoe is 111.

[0045] There are three setting positions of the auxiliary slot 4. In the cross section perpendicular to the central axis of the stator punching, when the auxiliary slot 4 is set at the setting position with the lowest number of positions, the angle between the line connecting the center of the slot bottom of the auxiliary slot 4 and the center of the stator punching and the center line of the tooth shoe 3 where the auxiliary slot 4 is located is b, b = (1 / 5~1 / 3)*a; when the auxiliary slot 4 is set at the middle setting position, the auxiliary slot 4 is located on the center line of the tooth shoe 3 where it is located; when the auxiliary slot 4 is set at the setting position with the highest number of positions, the angle between the line connecting the center of the slot bottom of the auxiliary slot 4 and the center of the stator punching and the center line of the tooth shoe 3 where the auxiliary slot 4 is located is c, c = (1 / 5~1 / 3)*a, where a is the tooth pole angle, a = 360 / z.

[0046] The number of tooth shoes 3 is 9, and three auxiliary slots 4 are provided on one of the tooth shoes 3. In the cross section perpendicular to the central axis of the stator punching sheet, the auxiliary slots 4 located on both sides of the circumference are symmetrical about the center line of the tooth shoe 3, and the auxiliary slot 4 located in the middle is located on the center line of the tooth shoe 3.

[0047] The auxiliary groove 4 has a width of 1.4 mm and a depth of 0.7 mm.

[0048] The width of the auxiliary slot 4 is L2, and the width of the stator slot is L1, where L2 = (1 / 3 to 4 / 3) * L1.

[0049] The cross section of the auxiliary groove 4 is semicircular, square or triangular.

[0050] According to an embodiment of the present application, the stator core includes the above-mentioned stator punchings, and multiple stator punchings are stacked into axial segments. The number of stator punchings is zt, where z is the number of tooth boots of each stator punching, and t is the number of stator punchings in each axial segment. t is a positive integer. Starting from the second stator punching axial segment, each stator punching axial segment is rotated by a tooth pole angle a relative to the previous stator punching axial segment, where the tooth pole angle a = 360 / z.

[0051] Specifically, in this embodiment, the stator core has 9 teeth 2, with 9 stator slots formed between the teeth. The tooth pole angle is 40°, the total axial height is 45 mm, and it is divided into 9 equal sections, each 5 mm, and each section is 40° counterclockwise rotated relative to the next section, wherein the direction of rotation of the motor rotor 5 is counterclockwise. Each section of the core is formed by stacking a number of stator punchings less than 1 mm. The 9 teeth are referred to as the first to the ninth teeth in a counterclockwise direction, and auxiliary slots 4 are provided on the inner wall of the tooth shoe 3 of the tooth portion. The auxiliary slots 4 are referred to as the first to the third auxiliary slots in a clockwise direction. The first auxiliary slot forms a counterclockwise angle of 10° with the center line of the tooth shoe 3, the second auxiliary slot coincides with the center line of the tooth shoe 3, and the third auxiliary slot forms a clockwise angle of 10° with the center line of the tooth shoe 3. On each segmented iron core, the first tooth has no auxiliary slot, the second tooth has no auxiliary slot, the third tooth has the third auxiliary slot, the fourth tooth has the second auxiliary slot, the fifth tooth has the second and third auxiliary slots, the sixth tooth has the first auxiliary slot, the seventh tooth has the first and third auxiliary slots, the eighth tooth has the first and second auxiliary slots, and the ninth tooth has the first, second and third auxiliary slots.

[0052] The axial segments forming the stator core rotate nine times, with each axial segment rotating 40 degrees relative to the previous axial segment, and can rotate a full circle, so that the slot shapes of each axial segment overlap, but the two adjacent axial segments are asymmetric about the adjacent surface, so that the stator core can achieve the effect of rotating skew slots.

[0053] According to an embodiment of the present application, the permanent magnet motor includes a stator core, which is the stator core described above.

[0054] The permanent magnet motor further includes a motor rotor 5, which is arranged on the inner circumference of the stator core and forms an air gap with the stator core. The thickness of the air gap is H1, and the depth of the auxiliary slot 4 is H2, where H2 = (1 / 2 to 3 / 2) * H1.

[0055] The permanent magnet motor further includes a motor rotor 5 , which is arranged on the inner circumference of the stator core and forms an air gap with the stator core. The thickness of the air gap is 0.8 mm, and the slot width of the stator core is 3.2 mm.

[0056] See also Figure 7 As shown, the motor of the present application has a significantly reduced cogging torque and improved output torque quality compared to the motor in the prior art.

[0057] See also Figure 8 As shown, by using the motor of the present application, the torque ripple is reduced from 8.3% to 7.5% compared with the motor in the prior art, which effectively reduces the torque ripple.

[0058] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0059] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application. The above are merely preferred embodiments of the present application. It should be noted that those skilled in the art may make various improvements and variations without departing from the technical principles of the present application, and such improvements and variations shall also be considered within the scope of protection of the present application.

Claims

1. A stator punching sheet, characterized in that: The invention comprises a yoke (1), a tooth portion (2), and a tooth shoe (3) arranged on a side of the tooth portion (2) away from the yoke (1); the tooth portion (2) is evenly distributed along the circumference of the yoke (1); auxiliary grooves (4) are provided on the inner peripheral walls of at least some of the tooth shoes (3); and the inner peripheral walls of at least two adjacent tooth shoes (3) have different structures. The number of tooth shoes (3) of the stator punching sheet is z, the total number of the setting positions of the auxiliary slot (4) on a single tooth shoe (3) is n, and 2 n ≤z<2 n+1 , one of the tooth boots (3) is used as the initial tooth boot (3), the initial tooth boot (3) is not provided with an auxiliary groove (4), starting from the initial tooth boot (3), along the rotation direction of the motor rotor (5), in the continuous 2 n Each tooth shoe (3) is provided with an auxiliary groove (4), and the auxiliary grooves (4) on at least two adjacent tooth shoes (3) are different in number or position, so that the adjacent tooth shoes (3) form different tooth shoe structures.

2. The stator sheet according to claim 1, characterized in that: The auxiliary grooves (4) are provided on the inner peripheral walls of at least two adjacent tooth shoes (3), and the auxiliary grooves (4) on the inner peripheral walls of the two adjacent tooth shoes (3) have the same structure.

3. The stator punching sheet according to claim 2, characterized in that: The auxiliary grooves (4) on the inner peripheral walls of the two adjacent tooth shoes (3) have the same structure and number, and at least some of the auxiliary grooves (4) are located in different positions.

4. The stator sheet according to claim 1, characterized in that: The auxiliary groove (4) is provided on the inner peripheral walls of at least two adjacent tooth shoes (3), and the auxiliary grooves (4) on the inner peripheral walls of the two adjacent tooth shoes (3) have different structures.

5. The stator punching sheet according to claim 1, characterized in that: Wherein n is the total number of setting positions of the auxiliary slot (4) on a single tooth shoe (3); when the auxiliary slot (4) is set at a setting position on the tooth shoe (3), the setting position is marked as 1; when the auxiliary slot (4) is not set at a setting position, the setting position is marked as 0; on any tooth shoe (3), along the rotation direction of the motor rotor (5), the binary digits of the setting position are arranged from low to high, and in the continuous 2 n -1 tooth shoe (3), in order from small to large, the arrangement positions of the auxiliary grooves (4) are arranged in sequence on each tooth shoe (3) in a binary manner.

6. The stator sheet according to claim 5, characterized in that: The number of the tooth shoes (3) is 9, wherein the auxiliary slots (4) are not provided on the initial tooth shoe (3) and the last tooth shoe (3); along the rotation direction of the motor rotor (5), the initial tooth shoe (3) is the first tooth shoe, the last tooth shoe (3) is the ninth tooth shoe, the binary number formed by the auxiliary slots (4) on the second tooth shoe is 001, the binary number formed by the auxiliary slots (4) on the third tooth shoe is 010, the binary number formed by the auxiliary slots (4) on the fourth tooth shoe is 011, the binary number formed by the auxiliary slots (4) on the fifth tooth shoe is 100, the binary number formed by the auxiliary slots (4) on the sixth tooth shoe is 101, the binary number formed by the auxiliary slots (4) on the seventh tooth shoe is 110, and the binary number formed by the auxiliary slots (4) on the eighth tooth shoe is 111.

7. The stator sheet according to claim 6, characterized in that: The auxiliary slot (4) is arranged at three positions. In a cross section perpendicular to the central axis of the stator punching sheet, when the auxiliary slot (4) is arranged at the lowest position, the angle between the line connecting the center of the slot bottom of the auxiliary slot (4) and the center of the stator punching sheet and the center line of the tooth shoe (3) where the auxiliary slot (4) is located is b, b=(1 / 5-1 / 3)*a; when the auxiliary slot (4) is arranged at the middle position, the auxiliary slot (4) is located on the center line of the tooth shoe (3) where the auxiliary slot (4) is located; when the auxiliary slot (4) is arranged at the highest position, the angle between the line connecting the center of the slot bottom of the auxiliary slot (4) and the center of the stator punching sheet and the center line of the tooth shoe (3) where the auxiliary slot (4) is located is c, c=(1 / 5-1 / 3)*a, wherein a is the tooth pole angle, a=360 / z.

8. The stator punching sheet according to claim 2, characterized in that: The number of the tooth shoes (3) is 9, and three auxiliary slots (4) are provided on one of the tooth shoes (3). In a cross section perpendicular to the central axis of the stator punching sheet, the auxiliary slots (4) located on both sides of the circumference are symmetrical about the center line of the tooth shoe (3), and the auxiliary slot (4) located in the middle is located on the center line of the tooth shoe (3).

9. The stator lamination according to any one of claims 1 to 8, characterized in that: The auxiliary groove (4) has a width of 1.4 mm and a depth of 0.7 mm.

10. The stator lamination according to any one of claims 1 to 8, characterized in that: The width of the auxiliary slot (4) is L2, and the width of the stator slot is L1, wherein L2=(1 / 3 to 4 / 3)*L1.

11. The stator lamination according to any one of claims 1 to 8, characterized in that: The cross section of the auxiliary groove (4) is semicircular, square or triangular.

12. A stator core, characterized in that: The stator lamination comprises any one of claims 1 to 9, wherein a plurality of the stator laminations are stacked into axial segments, the number of stator laminations is zt, z is the number of tooth boots of each stator lamination, t is the number of stator laminations in each axial segment, t is a positive integer, and starting from the second stator lamination axial segment, each stator lamination axial segment is rotated relative to the previous stator lamination axial segment by a tooth pole angle a, wherein the tooth pole angle a=360 / z.

13. A permanent magnet motor, comprising a stator core, characterized in that: The stator core is the stator core according to any one of claims 1 to 12.

14. The permanent magnet motor according to claim 13, characterized in that: The permanent magnet motor further comprises a motor rotor (5), which is arranged on the inner circumference of the stator core and forms an air gap with the stator core. The thickness of the air gap is H1, and the depth of the auxiliary slot (4) is H2, wherein H2=(1 / 2 to 3 / 2)*H1.

15. The permanent magnet motor according to claim 13, characterized in that: The permanent magnet motor further comprises a motor rotor (5), which is arranged on the inner circumference of the stator core and forms an air gap with the stator core. The thickness of the air gap is 0.8 mm, and the slot width of the stator core is 3.2 mm.

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