Rotor punching, motor rotor and motor

Abstract

The present application relates to the field of motor technology and discloses a rotor lamination, a rotor for a motor, and a motor. The rotor lamination includes: a plurality of magnetic steel slots and a plurality of slit groups. The magnetic steel slots are symmetrically structured and evenly distributed along the circumference of the rotor lamination. The slit groups are arranged on the side of the magnetic steel slots away from the center of the rotor lamination. The slit groups correspond one-to-one with the magnetic steel slots and include a plurality of slits connected to the magnetic steel slots. Compared with the prior art, the permanent magnets in the magnetic steel slots can be directly dissipated with heat through the plurality of slits. This reduces electromagnetic force while increasing heat dissipation channels. Furthermore, because the plurality of slits are symmetrically distributed relative to the axis of symmetry of the magnetic steel slots, the uniformity of heat dissipation is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of motors, and in particular to a rotor punching, a rotor of a motor, and a motor. Background Art

[0002] The core component of the motor is the rotor, which is composed of multiple stacked rotor punchings. Multiple magnetic steel slots are set on the rotor punchings to accommodate permanent magnets. In order to organize the magnetic flux and improve vibration, multiple slits are often set on one side of the magnetic steel slots. The slits in the existing rotor punchings are set independently from the magnetic steel slots. When the rotor runs at high speed, the motor vibrates and makes loud noises, and the heat of the magnetic steel is concentrated, which can easily lead to demagnetization of the permanent magnets and poor reliability of the rotor. Summary of the Invention

[0003] In order to solve the technical problems of high rotor noise and heat concentration, the main purpose of this application is to provide a rotor punching, a motor rotor and a motor that reduce noise and avoid heat concentration.

[0004] To achieve the above-mentioned invention objectives, this application adopts the following technical solutions:

[0005] According to one aspect of the present application, a rotor punching is provided, comprising:

[0006] A plurality of magnetic steel slots, wherein the magnetic steel slots are axisymmetric and are evenly distributed along the circumference of the rotor punching;

[0007] A plurality of slit groups are provided on a side of the magnetic steel slot away from the center of the rotor punching, the slit groups correspond to the magnetic steel slots one by one, and the slit groups include a plurality of slits connected to the magnetic steel slots.

[0008] According to one embodiment of the present application, the center line of each of the slits has a first intersection with the axial symmetry line of the magnetic steel slot, and the first intersection is located on the outside of the rotor punching.

[0009] According to one embodiment of the present application, each slit group includes two pairs of slits symmetrical about the center line of the magnetic steel slot. As the position of the slit gradually moves away from the center line of the magnetic steel slot, the first intersection formed by the intersection of the center line of the slit and the axial symmetry line of the magnetic steel slot gradually approaches the center of the rotor punching.

[0010] According to one embodiment of the present application, each of the slit groups includes at least three pairs of slits symmetrical about the center line of the magnetic steel slot. As the position of the slit gradually moves away from the center line of the magnetic steel slot, the first intersection formed by the intersection of the center line of the slit and the axial symmetry line of the magnetic steel slot first gradually moves away from the center of the rotor punching, and then gradually approaches the center of the rotor punching.

[0011] According to one embodiment of the present application, the multiple slits in the slit group include a third slit located at the end of the magnetic steel slot, and the third slit includes a first extension portion and a second extension portion that are connected. The first extension portion is located on the side of the magnetic steel slot away from the center of the rotor punching, and the second extension portion is located on the side of the magnetic steel slot close to the center of the rotor punching. The center line of the first extension portion and the axial symmetry line of the magnetic steel slot have the first intersection, and the center line of the second extension portion and the axial symmetry line of the magnetic steel slot have the second intersection, and the second intersection is located on the outside of the rotor punching.

[0012] According to one embodiment of the present application, the distance between the first intersection corresponding to the first extension portion and the center of the rotor punching is D1, and the distance between the second intersection corresponding to the second extension portion and the center of the rotor punching is D2, wherein D1<D2.

[0013] According to one embodiment of the present application, the length of the slit in its extending direction is L1, the width of the slit perpendicular to its extending direction is W1, and the width of the magnetic steel slot is W2, wherein L1>W2>W1.

[0014] According to one embodiment of the present application, the cross-section of the magnetic steel slot is in a straight or V-shape.

[0015] According to one embodiment of the present application, it further includes a plurality of through holes, and the plurality of through holes are spaced apart and arranged on one side of the magnetic steel slot close to the center of the rotor punching.

[0016] According to another aspect of the present application, a rotor of a motor is provided, comprising the rotor punching sheet.

[0017] According to another aspect of the present application, a motor is provided, comprising the rotor of the above motor.

[0018] As can be seen from the above technical solution, the advantages and positive effects of the rotor punching and the motor rotor of the present application are:

[0019] Multiple magnetic steel slots are evenly distributed along the circumference of the rotor punching, and multiple slit groups are arranged on the side of the magnetic steel slot away from the center of the rotor punching. The slit groups correspond to the magnetic steel slots one by one, thereby improving the uniformity of heat dissipation. Since the slit group includes multiple slits connected to the magnetic steel slots, the permanent magnets in the magnetic steel slots can be directly dissipated through the multiple slits. On the basis of reducing the electromagnetic force, the heat dissipation channel is increased. Moreover, since the multiple slits are symmetrically distributed relative to the axial symmetry line of the magnetic steel slot, the uniformity of heat dissipation is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 A schematic diagram of the overall structure of a rotor punching provided in an embodiment of the present application;

[0023] Figure 2 This is a schematic diagram of the enlarged structure of point A in a rotor punching provided in an embodiment of the present application;

[0024] Figure 3 Another schematic diagram of the overall structure of a rotor punching provided in an embodiment of the present application;

[0025] Figure 4 This is a schematic diagram of the enlarged structure of point B in a rotor punching provided in an embodiment of the present application;

[0026] Figure 5 A schematic diagram of the partial structure of a rotor punching at position B provided in an embodiment of the present application;

[0027] Figure 6 This is a schematic structural diagram of the distribution state of the first intersection point and the second intersection point in a rotor punching provided in an embodiment of the present application.

[0028] in:

[0029] 100, rotor punching; 110, edge line; 120, rotor punching center;

[0030] 10. Magnetic steel slot; 11. Axial symmetry line of the magnetic steel slot;

[0031] 20. Slit group; 21. Slit; 211. Center line of the slit; 212. First slit; 213. Second slit; 214. Third slit; 241. First extension; 242. Second extension;

[0032] 30. First intersection; 40. Second intersection; 50. Through hole. DETAILED DESCRIPTION

[0033] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0034] The core component of the motor is the rotor, which is composed of multiple stacked rotor punchings. Multiple magnetic steel slots are set on the rotor punchings to accommodate permanent magnets. In order to organize the magnetic flux and improve vibration, multiple slits are often set on one side of the magnetic steel slots. The slits in the existing rotor punchings are set independently from the magnetic steel slots, and the slits and magnetic steel slots are not connected to each other. As a result, when the rotor runs at high speed, the motor vibrates and makes a lot of noise. The heat generated by the permanent magnets in the rotor is easily concentrated in the magnetic steel slots, which easily leads to the demagnetization of the permanent magnets and poor reliability of the rotor. In order to solve the technical problems of high rotor noise and heat concentration, according to one aspect of the present application, a rotor punching is provided, comprising:

[0035] A plurality of magnetic steel slots 10, wherein the magnetic steel slots 10 are symmetrically structured and are evenly distributed along the circumference of the rotor sheet 100;

[0036] A plurality of slit groups 20 are arranged on the side of the magnetic steel slot 10 away from the center 120 of the rotor punching 100. The slit groups 20 correspond to the magnetic steel slots 10 one by one. The slit groups 20 include a plurality of slits 21 connected to the magnetic steel slots 10.

[0037] As an example, refer to Figures 1-6 As shown, a plurality of magnetic steel slots 10 are uniformly distributed at equal angles along the circumference of the rotor punching 100. After the slit groups 20 correspond to the magnetic steel slots 10 one by one, on the one hand, the magnetic flux of the permanent magnets in the magnetic steel slots 10 is sorted by the slit groups 20 to reduce the electromagnetic force. On the other hand, since each magnetic steel slot 10 can be connected to the magnetic steel slot 10 through the plurality of slits 21 in the slit group 20, the heat dissipation channel area of ​​the magnetic steel slot 10 is increased, the heat dissipation efficiency is improved, and the reliability of the performance of the rotor during use is improved.

[0038] As an example, the ends of the plurality of slits 21 are located on a side close to the edge line 110 of the rotor punching 100, that is, the slits 21 are opened inside the rotor punching 100, thereby reducing the vibration between the slits 21 and the air outside the rotor punching 100, thereby further reducing the noise of the rotor operation on the basis of improving the stability of the mechanical structure of the rotor punching 100.

[0039] According to one embodiment of the present application, the center line of each of the slits 21 and the axial symmetry line of the magnetic steel slot 10 have a first intersection 30 , and the first intersection 30 is located outside the rotor punching 100 .

[0040] It should be noted that the centerline of the slit 21 is a line located between the two extended sides of the slit 21, extending along the extension direction of the slit 21, and equidistant from all opposite points on the two extended sides of the slit 21. The axisymmetric line of the magnetic steel slot 10 is the symmetric centerline of the magnetic steel slot 10. It should be further noted that since the plurality of magnetic steel slots 10 are uniformly distributed at equal angles along the circumference of the rotor punching 100, the symmetric centerline of the magnetic steel slot 10 passes through the center of the rotor punching 100. In other words, the axisymmetric line of the magnetic steel slot 10 is on the straight line along the diameter of the rotor punching 100.

[0041] As an example, refer to Figure 2 As shown, when the center line of each slit 21 and the axisymmetric line of the magnetic steel slot 10 have a first intersection 30, so that the first intersection 30 is located outside the edge line 110, the angle between the extension direction of each slit 21 and the extension direction of the magnetic steel slot 10 can be controlled to be within a large range, thereby enabling the opened slits 21 to regulate the flow of the magnetic field on the stator and rotor, reasonably dredge the magnetic circuit, reduce the low-order harmonics of the air gap magnetic density, and thus reduce noise. Moreover, since the slits 21 are connected to the magnetic steel slot 10, the low-order harmonics of the air gap magnetic density can be further reduced, which can further reduce the electromagnetic force that causes noise, thereby fundamentally reducing noise. As an example, the cross-section of the magnetic steel slot 10 is a straight line.

[0042] In the prior art, a slit is often opened between the magnetic steel slot and the outer edge of the rotor to reduce the electromagnetic force. Since there is no connection between the slit and the magnetic steel slot, essentially only the high-order harmonics are reduced. Some low-order harmonics flow through the channel between the slit and the magnetic steel slot and enter the air gap in large quantities, thereby causing larger low-order harmonics. In some conventional slot-pole motors, such as the most commonly used 9-slot 6-pole motor, the minimum non-zero-order electromagnetic force (6 times the frequency) is caused by the low-order harmonics of the magnetic field. Therefore, low-order harmonics are the biggest source of noise and vibration. Therefore, by adopting the present technical solution, controlling the first intersection 30 to be located outside the edge line 110 and connecting the slit 21 to the magnetic steel slot 10, the minimum non-zero-order electromagnetic force caused by the abundance of low-order harmonics can be greatly reduced, thereby greatly reducing the electromagnetic noise.

[0043] According to one embodiment of the present application, each slit group 20 includes two pairs of slits 21 that are symmetrical about the axial symmetry line of the magnetic steel slot 10. As the position of the slit gradually moves away from the axial symmetry line of the magnetic steel slot 10, the first intersection formed by the intersection of the center line of the slit and the axial symmetry line of the magnetic steel slot gradually approaches the center of the rotor punching 100.

[0044] refer to Figure 2 As shown, on one side of the axial symmetry line of the magnetic steel slot 10, two slits 21 are arranged in sequence along the axial symmetry line away from the magnetic steel slot 10, and one of the slits 21 is located at the end of the magnetic induction slot (equivalent to the first extension portion 241), so that the distance between the two first intersection points 30 formed by the two slits 21 and the center 120 of the rotor punching 100 is reduced in sequence along the axial symmetry line away from the magnetic steel slot 10, so that the angle between the center line of the slit 21 closer to the magnetic steel slot 10 and the center line of the magnetic steel slot 10 gradually increases, and then the magnetic flux flow is guided by multiple slits 21, so that the magnetic field generated by the permanent magnet in the magnetic steel slot 10 can be slowly concentrated and guided to the air gap, thereby effectively weakening the electromagnetic noise on the basis of increasing the area of ​​the heat dissipation channel.

[0045] According to one embodiment of the present application, each of the slit groups 20 includes at least three pairs of slits 21 that are symmetrical about the axial symmetry line of the magnetic steel slot 10. As the position of the slit gradually moves away from the axial symmetry line of the magnetic steel slot 10, the first intersection point formed by the intersection of the center line of the slit and the axial symmetry line of the magnetic steel slot first gradually moves away from the center of the rotor punching 100, and then gradually approaches the center 120 of the rotor punching.

[0046] As an example, the multiple slots 21 in each slot group 20 include a pair of first slots 212 and at least two pairs of second slots 213. On one side of the axis of symmetry of the magnetic steel slot 10, the multiple second slots 213 are spaced apart on both sides of the first slots 212, wherein:

[0047] From the axisymmetric line of the magnetic steel slot 10 toward the first slit 212 , the distances between the first intersection points 30 corresponding to the first slit 212 and the second slits 213 and the center 120 of the rotor sheet gradually increase.

[0048] From the first slit 212 toward the edge line 110 of the rotor punching 100 , the distances between the first intersection points 30 corresponding to the first slit 212 and the second slits 213 and the center 120 of the rotor punching gradually decrease.

[0049] As an example, refer to Figure 3As shown, on one side of the axial symmetry line of the magnetic steel slot 10, two slits 21 are sequentially arranged along the axial symmetry line away from the magnetic steel slot 10, so that the distance between the two first intersection points 30 corresponding to the two slits 21 and the center of the rotor punching 100 increases sequentially along the axial symmetry line away from the magnetic steel slot 10, so that the angle between the center line of the slit 21 closer to the magnetic steel slot 10 and the center line of the magnetic steel slot 10 gradually decreases, and then the magnetic flux flow is guided by multiple slits 21, and the magnetic field generated by the permanent magnet in the magnetic steel slot 10 can be slowly concentrated and guided to the air gap, thereby effectively weakening the electromagnetic noise on the basis of increasing the area of ​​the heat dissipation channel.

[0050] As an example, refer to Figure 3 As shown, on one side of the axial symmetry line of the magnetic steel slot 10, two slits 21 are sequentially arranged along the axial symmetry line away from the magnetic steel slot 10. In one embodiment, the two slits 21 can be arranged between the center line of the magnetic steel slot 10 and the end of the magnetic steel slot 10. At this time, the slit 21 close to the center line of the magnetic steel slot 10 is equivalent to the second slit 213, and the slit 21 close to the end of the magnetic steel slot 10 is equivalent to the first slit 212.

[0051] As an example, refer to Figure 3-Figure 5 As shown, three slits 21 are sequentially arranged on one side of the axis of symmetry of the magnetic steel slot 10 along the direction away from the axis of symmetry of the magnetic steel slot 10. In one embodiment, the slit 21 close to the center line of the magnetic steel slot 10 is equivalent to the second slit 213, and the middle slit 21 is equivalent to the first slit 212. From the axis of symmetry of the magnetic steel slot 10 toward the first slit 212, the distance between the first intersection points 30 corresponding to the first slit 212 and the second slits 213 and the center 120 of the rotor punching gradually increases; furthermore, the center line of the slit 21 near the middle of the permanent magnet, that is, the center line from the first slit 212 to the second slit 213 within the center line of the magnetic steel slot 10, gradually decreases the angle between the center line of the magnetic steel slot 10.

[0052] As an example, refer to Figure 3-Figure 5As shown, on one side of the center line of the magnetic steel slot 10, three slits 21 are sequentially arranged along the axis of symmetry away from the magnetic steel slot 10. In one embodiment, the slit 21 from the center line of the first slit 212 to the end of the magnetic steel slot 10 (not shown in the figure) can be the second slit 213, and the slit 21 at the end of the magnetic induction slot is the second slit 213. In this case, the middle slit 21 is equivalent to the first slit 212, and the slit 21 at the end of the magnetic steel slot 10 is equivalent to the third slit 214. From the first slit 212 to the rotor punching 1 00, the distances between the first intersection points 30 corresponding to the first slits 212 and the second slits 213 and the center 120 of the rotor sheet gradually decrease, thereby making the center lines of the slits 21 at both ends of the permanent magnet embedded in the magnetic steel slot 10, that is, the center lines of the second slits 213 (equivalent to the first extension portion 241 in the figure) close to the end of the magnetic steel slot 10, and the center line of the magnetic steel slot 10 gradually larger. As a result, the magnetic field flow can be guided more reasonably, and the magnetic field can be gradually concentrated and guided to the air gap more effectively.

[0053] According to one embodiment of the present application, the multiple slits 21 in the slit group 20 include a third slit 214 located at the end of the magnetic steel slot 10, and the third slit 214 includes a first extension portion 241 and a second extension portion 242 that are connected. The first extension portion 241 is located on the side of the magnetic steel slot 10 away from the center of the rotor punching 100, and the second extension portion 242 is located on the side of the magnetic steel slot 10 close to the center of the rotor punching 100. The center line of the first extension portion 241 and the axial symmetry line of the magnetic steel slot 10 have a first intersection 30, and the center line of the second extension portion 242 and the axial symmetry line of the magnetic steel slot 10 have a second intersection 40, and the second intersection 40 is located on the outside of the rotor punching 100.

[0054] As an example, refer to Figure 3-Figure 5 As shown, the second extension portion 242 can reduce vibration while ensuring the mechanical stability of the rotor sheet 100 and further improve heat dissipation at the center 120 of the rotor sheet. As an example, the cross section of the magnetic steel slot 10 is V-shaped.

[0055] As an example, refer to Figure 3-Figure 5As shown, on one side of the center line of the magnetic steel slot 10, three slits 21 are arranged in sequence along the axial symmetry line away from the magnetic steel slot 10. In one embodiment, the first extension 241 located at the end of the magnetic induction slot is a second slit 213. At this time, the middle slit 21 is equivalent to the first slit 212. From the first slit 212 to the direction of the edge line 110 of the rotor punching 100, the distance between the first intersection 30 corresponding to the first slit 212 and the first extension 241 and the center 120 of the rotor punching gradually decreases. As a result, the center line of the slits 21 at both ends of the permanent magnet embedded in the magnetic steel slot 10, that is, the center line of the first extension 241, gradually increases with the center line of the magnetic steel slot 10. As a result, the magnetic field can be guided more reasonably and the magnetic field can be more effectively and slowly concentrated to the air gap.

[0056] According to one embodiment of the present application, the distance between the first intersection point 30 corresponding to the first extension portion 241 and the center 120 of the rotor sheet is D1, and the distance between the second intersection point 40 corresponding to the second extension portion 242 and the center 120 of the rotor sheet is D2, wherein D1<D2.

[0057] As an example, refer to Figure 6 As shown, further, by controlling the distance D2 between the second intersection 40 corresponding to the second extension portion 242 and the center 120 of the rotor sheet, D1 is controlled to be less than D2, and further controlling the angle between the center line of the first extension portion 241 and the center line of the magnetic steel slot 10 to be greater than the angle between the center line of the second extension portion 242 and the center line of the magnetic steel slot 10, thereby effectively guiding the magnetic field near the center position of the rotor sheet 100 to slowly concentrate and guide it to the air gap, further reducing the operating noise.

[0058] According to one embodiment of the present application, the length of the slit 21 in its extension direction is L1, the width of the slit 21 perpendicular to its extension direction is W1, and the slot width of the magnetic steel slot 10 is W2, wherein L1>W2>W1.

[0059] refer to Figure 5 As shown, when the slit 21 guiding the flow of magnetic flux and the width of the permanent magnet embedded in the magnetic steel slot 10 (equivalent to the width W2 of the magnetic steel slot 10) satisfy L1>W2>W1, the slit 21 can further improve the guidance of the flow of magnetic flux.

[0060] According to one embodiment of the present application, it further includes a plurality of through holes 50 , and the plurality of through holes 50 are spaced apart and arranged on one side of the magnetic steel slot 10 close to the center 120 of the rotor punching.

[0061] refer to Figure 1-Figure 5As shown, to reduce the demagnetization of the permanent magnets caused by high-speed heating, multiple through-holes 50 are provided at the lower end of the magnetic steel slots 10. These through-holes 50 are located adjacent to the permanent magnets and effectively remove heat from them. For uniform heat conduction, the through-holes 50 are arranged parallel to the magnetic steel slots 10.

[0062] More preferably, in order to be adjacent to the magnetic steel slot 10 and achieve a better heat conduction effect, the distance between the through hole 50 and the magnetic steel slot 10 is less than the width W2 of the magnetic steel slot 10 .

[0063] More preferably, in order not to affect the magnetic circuit, the spacing distance between adjacent through holes 50 should be greater than the distance between the through hole 50 and the magnetic steel slot 10.

[0064] As an example, the rotor structure using the technical solution of the present invention can significantly reduce the electromagnetic force by providing a slit 21 connected to the magnetic steel slot 10 and holes around the magnetic steel slot 10, while increasing the heat dissipation channel of the permanent magnet and improving reliability. The solutions provided in this application include:

[0065] 1. In the area formed by the magnetic steel slot 10 and the outer edge of the rotor, at least one pair of slits 21 are provided, symmetrical about the centerline of the magnetic steel slot 10 and connected to the magnetic steel slot 10. The slits 21 are elongated, and the intersection of the equidistant lines along the rotor radial direction and the centerline of the magnetic steel slot 10 is located outside the rotor arc.

[0066] 2. The width of the radial side of the slit 21 (equivalent to L1) is greater than the width of the circumferential side (equivalent to W1), and the width of the magnetic steel slot 10 (equivalent to W2) is between the radial width and the circumferential width of the slit 21.

[0067] 3. The distance from the intersection of the slit 21 and the center line of the magnetic steel slot 10 (equivalent to the first intersection 30) to the center of the rotor shaft (equivalent to the center of the rotor punching 120) first increases and then decreases in the direction close to the two ends of the magnetic steel slot 10 (refer to Figure 3-Figure 5 ).

[0068] 4. In the area formed by the magnetic steel slot 10 and the inner side of the rotor, there are multiple through holes 50 arranged parallel to the magnetic steel slot 10. The maximum distance between the through holes 50 and the magnetic steel slot 10 on the rotor is less than the width of the magnetic steel slot 10, and the minimum distance between adjacent through holes 50 on the rotor is greater than the minimum distance between the through holes 50 and the magnetic steel slot 10 on the rotor. The heat dissipation effect is improved through the through holes 50.

[0069] 5. A protrusion (equivalent to a second extension) connected to the magnetic steel slot 10 is provided at both ends of the magnetic steel slot 10. The protrusion extends toward the inside of the rotor, and the center line of the second extension forms an intersection with the center line of the magnetic steel outside the rotor (equivalent to the second intersection 40).

[0070] Conventional compressors currently operate in the 10-120 Hz range. Exceeding 120 Hz generates significant vibration and noise. High speeds also generate significant internal heat in the motor, which can lead to irreversible demagnetization of the permanent magnets in permanent magnet motors, resulting in poor reliability. Research efforts focused on compressors operating above 120 Hz, particularly high-speed motors, have focused on addressing noise and heat generation.

[0071] The present invention simultaneously addresses the issues of prominent electromagnetic noise and vibration, as well as high motor heat generation, during high-speed operation of the compressor motor. Specifically, the slits 21 of the present invention regulate the flow of magnetic fields between the stator and rotor, effectively unblocking the magnetic circuit and reducing low-order harmonics of the air gap flux density. This significantly reduces the electromagnetic force that causes noise, thereby fundamentally reducing noise.

[0072] Since most existing solutions involve opening a slit between the magnetic steel slot and the outer edge of the rotor to reduce the electromagnetic force, and since there is no connection between the slit and the magnetic steel slot, essentially only the high-order harmonics are reduced. Some low-order harmonics flow through the channel between the slit and the magnetic steel slot and enter the air gap in large quantities, thereby causing larger low-order harmonics. In some conventional slot-pole motors, such as the most commonly used 9-slot 6-pole motor, the minimum non-zero-order electromagnetic force (6 times the frequency) is caused by the low-order harmonics of the magnetic field, and is the biggest source of noise and vibration. The use of the technology of the present invention can greatly reduce this minimum non-zero-order electromagnetic force caused by the abundance of low-order harmonics, thereby greatly reducing electromagnetic noise.

[0073] The present invention employs at least one pair of slits 21 connecting the magnetic steel slots 10. These slits 21 intersect the centerline of the magnetic steel slots 10. To properly guide the magnetic field, the slits 21 should be elongated overall. To gradually concentrate the magnetic field into the air gap, the slits 21 near the ends of the permanent magnets embedded in the magnetic steel slots 10 typically have a larger angle with the centerline of the magnetic steel slots 10, while the slits 21 near the center of the permanent magnets typically have a smaller angle with the centerline of the magnetic steel slots 10. Therefore, an optimal solution exists for the angles between the multiple slits 21 and the centerline of the magnetic steel slots 10: the intersection of the slits 21 and the centerline of the magnetic steel slots 10 is located outside the rotor region, and the distance from the intersection to the rotor center increases and then decreases from the centerline of the magnetic steel slots 10 toward the ends of the magnetic steel slots 10.

[0074] Furthermore, the slit 21 guiding the flow of magnetic flux and the permanent magnet embedded in the magnetic steel slot 10 satisfy a certain relationship, which can better complete the guidance work, that is, the thickness of the permanent magnet (theoretically equal to the width W2 of the magnetic steel slot 10) should be between the circumferential width and radial width of the slit 21.

[0075] Furthermore, to reduce the demagnetization of the permanent magnets caused by high-speed heating, multiple holes are provided at the lower end of the magnetic steel slots 10. These holes are located adjacent to the permanent magnets and effectively remove heat from them. For uniform heat conduction, the holes are arranged parallel to the magnetic steel slots 10.

[0076] More preferably, the distance between the hole and the magnetic steel slot 10 is smaller than the width of the magnetic steel slot 10 in order to achieve better heat conduction effect.

[0077] More preferably, in order not to affect the magnetic circuit, the circumferential distance formed by adjacent holes should be greater than the distance between the holes and the magnetic steel slot 10.

[0078] To further improve the performance, in order to avoid high-temperature demagnetization of the permanent magnets at high speeds, on the one hand, it is necessary to provide slits 21 and holes connected to the magnetic steel slots 10 as heat dissipation holes to cool the permanent magnets. On the other hand, it is necessary to provide slits 21 extending from both ends of the magnetic steel slots 10 toward the inside of the rotor to improve the demagnetization resistance of the permanent magnets. This is because the demagnetization magnetic field flows around the slits 21, reducing the extent to which the demagnetization magnetic field acts on the permanent magnets.

[0079] According to another aspect of the present application, a rotor of a motor is provided, comprising the rotor punching sheet.

[0080] According to another aspect of the present application, a motor is provided, comprising the rotor of the above-mentioned motor. It should be noted that, in this article, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "includes" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0081] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A rotor punching, characterized in that: include: A plurality of magnetic steel slots (10), wherein the magnetic steel slots (10) are of an axisymmetric structure, and the plurality of magnetic steel slots (10) are evenly distributed along the circumference of the rotor punching (100); A plurality of slit groups (20), wherein the plurality of slit groups (20) are arranged on a side of the magnetic steel slot (10) away from the center of the rotor punching (100), the slit groups (20) correspond to the magnetic steel slot (10) one by one, the slit groups (20) include a plurality of slits (21) connected to the magnetic steel slot (10), the center line of each slit (21) and the axisymmetric line of the magnetic steel slot (10) have a first intersection (30), and the first intersection (30) is located at the center of the rotor punching (100). On the outside, each of the slit groups (20) includes at least three pairs of slits (21) symmetrical about the axisymmetric line of the magnetic steel slot (10), and as the position of the slit gradually moves away from the axisymmetric line of the magnetic steel slot (10), the first intersection point formed by the intersection of the center line of the slit and the axisymmetric line of the magnetic steel slot first gradually moves away from the center of the rotor punching (100) and then gradually approaches the center of the rotor punching. The multiple slits (21) in the slit group (20) include the slits located at the ends of the magnetic steel slot (10). A third slit (214), the third slit (214) comprising a first extension portion (241) and a second extension portion (242) connected to each other, the first extension portion (241) being located on a side of the magnetic steel slot (10) away from the center of the rotor punching (100), the second extension portion (242) being located on a side of the magnetic steel slot (10) close to the center of the rotor punching (100), the center line of the first extension portion (241) and the axisymmetric line of the magnetic steel slot (10) having the first intersection point (3 0), a center line of the second extension portion (242) and an axial symmetry line of the magnetic steel slot (10) have a second intersection point (40), the second intersection point (40) is located outside the rotor punching (100), a distance between a first intersection point (30) corresponding to the first extension portion (241) and a center point (120) of the rotor punching is D1, and a distance between a second intersection point (40) corresponding to the second extension portion (242) and a center point (120) of the rotor punching is D2, wherein D1<D2.

2. The rotor punching according to claim 1, characterized in that: The length of the slit (21) in its extension direction is L1, the width of the slit (21) perpendicular to its extension direction is W1, and the width of the magnetic steel slot (10) is W2, wherein L1>W2>W1.

3. The rotor punching according to claim 1, characterized in that: The cross section of the magnetic steel slot (10) is in a straight or V shape.

4. The rotor punching according to any one of claims 1 to 3, characterized in that: It also includes a plurality of through holes (50), wherein the plurality of through holes (50) are arranged at intervals on one side of the magnetic steel slot (10) close to the center (120) of the rotor punching sheet.

5. A rotor of a motor, characterized in that: The invention comprises the rotor punching sheet according to any one of claims 1 to 4.

6. A motor, characterized in that: A rotor comprising the motor according to claim 5.

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