Rotor punching sheet, rotor iron core, rotor and motor

Abstract

The invention provides a rotor punching sheet, a rotor iron core, a rotor and a motor, the rotor punching sheet comprises a punching sheet main body and permanent magnet grooves, the permanent magnet grooves comprise inner layer permanent magnet grooves and outer layer permanent magnet grooves, and the outer layer first permanent magnet grooves and the outer layer second permanent magnet grooves are symmetrical relative to a d axis; the punching sheet main body is also provided with an inner layer permanent magnet groove center line L; the inner-layer permanent magnet grooves comprise inner-layer first permanent magnet grooves located on one side of the L and inner-layer second permanent magnet grooves located on the other side of the L, and the inner-layer first permanent magnet grooves and the inner-layer second permanent magnet grooves are the same in shape and area size. The minimum distance between the inner-layer first permanent magnet groove and the L is equal to the minimum distance between the inner-layer second permanent magnet groove and the L, but the inner-layer first permanent magnet groove and the inner-layer second permanent magnet groove are asymmetrical relative to the L. According to the invention, the magnetic leakage between the magnetic poles can be reduced, the air gap waveform with better sinusoidal property can be obtained, the harmonic distortion rate can be improved, and the harmonic can be reduced and improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and particularly to a rotor punching sheet, a rotor core, a rotor and a motor. Background Art

[0002] Since a permanent magnet motor uses permanent magnet materials for excitation and does not require external energy to establish a magnetic field in the air gap of the motor, it has a high power factor. Therefore, it has a high efficiency within the working load, and the permanent magnet motor has a high power density, and the volume and mass of the motor are small. With the increasing requirements of the national energy consumption standard, permanent magnet motors are more and more widely used.

[0003] When a permanent magnet synchronous motor operates, the energized stator coil will form a demagnetization effect on the permanent magnets on the rotor. When the motor is running normally, the running current is small, and the magnetic field intensity generated by the armature winding is not sufficient to demagnetize the permanent magnets. However, when the motor encounters abnormal conditions, such as blocking or short circuit, etc., it will cause an instantaneous increase in current, which is likely to cause irreversible demagnetization of the permanent magnets, affecting the performance and reliability of the motor. In order to ensure the normal operation of the motor, it is necessary to fully analyze and check the demagnetization characteristics of the motor permanent magnets during motor development to ensure the demagnetization margin of the motor and improve the reliability of the motor. In addition, the motor body structure and the inverter are the main factors causing low-order current harmonics in the permanent magnet synchronous motor. In terms of the motor body, factors such as cogging effect, magnetic circuit saturation effect, and rotor pole structure cause distortion of the output voltage. These factors will cause excessive cogging torque and harmonics of the machine, which will in turn affect the motor performance, application accuracy and accuracy.

[0004] Due to technical problems such as large harmonics in the rotor punching sheet in the prior art, the present invention researches and designs a rotor punching sheet, a rotor core, a rotor and a motor. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect of large harmonics in the rotor punching sheet in the prior art, so as to provide a rotor punching sheet, a rotor core, a rotor and a motor.

[0006] To solve the above problems, the present invention provides a rotor punching sheet, which includes:

[0007] A punching sheet main body and permanent magnet slots. The permanent magnet slots are arranged on the punching sheet main body. The permanent magnet slots include an inner-layer permanent magnet slot and an outer-layer permanent magnet slot. Along the radial direction of the rotor punching sheet, the outer-layer permanent magnet slot is located outside the inner-layer permanent magnet slot. The punching sheet main body has a d-axis. The outer-layer permanent magnet slot includes an outer-layer first permanent magnet slot and an outer-layer second permanent magnet slot. The outer-layer first permanent magnet slot is located on one side of the d-axis, and the outer-layer second permanent magnet slot is located on the other side of the d-axis, and the outer-layer first permanent magnet slot and the outer-layer second permanent magnet slot are symmetrical with respect to the d-axis;

[0008] The punching sheet body also has a center line L of the inner-layer permanent magnet slot, and the L is parallel to the d-axis and spaced apart by a preset distance greater than 0; the inner-layer permanent magnet slot includes an inner-layer first permanent magnet slot on one side of the L and an inner-layer second permanent magnet slot on the other side of the L, and the inner-layer first permanent magnet slot and the inner-layer second permanent magnet slot have the same shape and area size, the minimum distance between the inner-layer first permanent magnet slot and the L and the minimum distance between the inner-layer second permanent magnet slot and the L are equal, but the inner-layer first permanent magnet slot and the inner-layer second permanent magnet slot are asymmetric with respect to the L.

[0009] In some embodiments,

[0010] Relatively, the inner-layer first permanent magnet slot is disposed relatively close to the outer circumferential surface of the rotor punching sheet, and the inner-layer second permanent magnet slot is disposed relatively far from the outer circumferential surface of the rotor punching sheet, and the minimum distance between the inner-layer first permanent magnet slot and the outer circumferential surface is greater than the minimum distance between the inner-layer second permanent magnet slot and the outer circumferential surface.

[0011] In some embodiments,

[0012] The distance between the center line L of the inner-layer permanent magnet slot and the d-axis is d1, and there is: d1 = 1.2 - 1.6 mm.

[0013] In some embodiments,

[0014] When the motor rotates clockwise, the inner-layer permanent magnet slot biases to the clockwise side of the d-axis, that is, the L is located at the position where the d-axis is translated by d1 in the clockwise direction;

[0015] When the motor rotates counterclockwise, the inner-layer permanent magnet slot biases to the counterclockwise side of the d-axis, that is, the L is located at the position where the d-axis is translated by d1 in the counterclockwise direction.

[0016] In some embodiments,

[0017] The inner-layer first permanent magnet slot is located on one side of the counterclockwise direction of the L, and the inner-layer second permanent magnet slot is located on one side of the clockwise direction of the L;

[0018] When the motor rotates clockwise, the minimum distance between the inner-layer first permanent magnet slot and the d-axis is less than the minimum distance between the inner-layer second permanent magnet slot and the d-axis;

[0019] When the motor rotates counterclockwise, the minimum distance between the inner-layer first permanent magnet slot and the d-axis is greater than the minimum distance between the inner-layer second permanent magnet slot and the d-axis.

[0020] In some embodiments,

[0021] Along the radial direction of the rotor punching sheet, the outermost side of the inner first permanent magnet groove is a first arc edge, the outermost side of the inner second permanent magnet groove is a second arc edge. The center of the first arc edge coincides with the center point O of the shaft hole of the rotor punching sheet, and the center of the second arc edge coincides with the center point O of the shaft hole of the rotor punching sheet. The radius of the first arc edge is R1, the radius of the second arc edge is R2, and the radius of the rotor punching sheet is R. Among them, there is a constraint relationship: R2 = R1 - (-0.1 to 0.15) mm, R1 = R - (0.8 to 1.2) mm.

[0022] In some embodiments,

[0023] Along the radial direction of the rotor punching sheet, the inner end of the inner first permanent magnet groove and the inner end of the inner second permanent magnet groove are opposite in the circumferential direction of the rotor punching sheet, and the interval position between them forms an inner magnetic isolation bridge a. The width of the inner magnetic isolation bridge a in the circumferential direction of the rotor punching sheet is da. Along the radial direction of the rotor punching sheet, the inner end of the outer first permanent magnet groove and the inner end of the outer second permanent magnet groove are opposite in the circumferential direction of the rotor punching sheet, and the interval position between them forms an outer magnetic isolation bridge b. The width of the outer magnetic isolation bridge b in the circumferential direction of the rotor punching sheet is db. Among them, there is a constraint relationship: db = 0.8 to 1.8 mm, da = (1.5 to 2) db, d1 = da - db.

[0024] The present invention also provides a rotor core, which includes the aforementioned rotor punching sheet, and multiple layers of rotor punching sheets are stacked to form the rotor core.

[0025] The present invention also provides a rotor, which includes the aforementioned rotor core, and further includes a permanent magnet, and the permanent magnet is arranged in the permanent magnet groove.

[0026] The present invention also provides a motor, which includes the aforementioned rotor.

[0027] A rotor punching sheet, a rotor core, a rotor and a motor provided by the present invention have the following beneficial effects:

[0028] 1. In the present invention, the permanent magnet slots on the rotor punching are divided into inner and outer permanent magnet slots. The outer permanent magnet slots include outer first and outer second permanent magnet slots symmetrically arranged with respect to the d-axis. The inner permanent magnet slots include an inner first permanent magnet slot and an inner second permanent magnet slot. The inner first and inner second permanent magnet slots are identical in size and shape and are asymmetrically arranged with respect to the center line L, which is a line parallel and offset to the d-axis. As a result, the outer permanent magnet slot B2 is symmetric about the magnetic pole center line d, just like a traditional rotor punching, while the inner permanent magnet slot B1 is asymmetric about the d-axis and forms a dislocation symmetry about the center line L. Different from the traditional rotor punching, the asymmetric rotor structure of the present invention can reduce the magnetic leakage between magnetic poles, increase the air-gap magnetic density, enhance the fundamental wave content, obtain an air-gap waveform with better sinusoidality, improve the harmonic distortion rate, reduce and improve harmonics, and at the same time has a significant effect on suppressing the cogging torque.

[0029] 2. The present invention also arranges the rotor punching such that when the motor rotates clockwise, the inner permanent magnet slot biases towards the clockwise side of the d-axis, that is, the L is located at a position where the d-axis is translated by d1 in the clockwise direction; when the motor rotates counterclockwise, the inner permanent magnet slot biases towards the counterclockwise side of the d-axis, that is, the L is located at a position where the d-axis is translated by d1 in the counterclockwise direction. After the inner permanent magnet is offset, the output torque of the motor can be basically kept unchanged, and the magnetic field line distribution is optimized, and the cogging torque and harmonic content are reduced.

[0030] 3. The present invention also sets the distance dl between L and the d-axis to satisfy dl = 1.2 - 1.6 mm. This constraint relationship can effectively reduce the magnetic leakage between poles without affecting the main magnetic circuit, reduce the demagnetization risk at the sharp corners of the permanent magnet, increase the high magnetic density region on the permanent magnet, improve the demagnetization resistance performance of the permanent magnet, expand the high magnetic density region on the permanent magnet, increase the magnetic density in the easily demagnetized region at the sharp corners of the permanent magnet, and greatly reduce the demagnetization risk of the permanent magnet.

[0031] 4. The present invention also forms the outermost side of the inner permanent magnet slot along the radial direction of the rotor punching sheet by a first arc edge B111 and a second arc edge B121. The centers of the first arc edge B111 and the second arc edge B121 coincide with the center point O of the rotor shaft hole. The radius of the first arc edge B111 is R1, the radius of the second arc edge B121 is R2, and the radius of the rotor punching sheet is R. Among them, there is a constraint relationship: R2 = R1 - (-0.1 to 0.15) mm, R1 = R - (0.8 to 1.2) mm. This constraint relationship forms magnetic isolation bridges between the first arc edge B111 and the second arc edge B121 and the outer edge of the rotor respectively, and ensures that the width difference between the two magnetic isolation bridges is small, so that the inner permanent magnet slot forms a misaligned symmetric structure with respect to the straight line L. After optimization design, the motor with this misaligned symmetric structure can effectively alleviate the high-order harmonic phenomenon, greatly increase the fundamental wave amplitude, be closer to sine on the waveform, and can effectively weaken the cogging torque. At the same time, it prevents serious magnetic leakage caused by too large magnetic isolation bridges on both sides, reducing the electromagnetic performance of the motor, and too small magnetic isolation bridges causing stress concentration problems in the rotor and reducing the rotor strength. Meeting this constraint relationship can ensure the optimal output torque performance of the motor and meet the requirements of the rotor strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a top view structural diagram of the rotor punching sheet of the present invention;

[0033] Figure 2 is Figure 1 a partial structure amplification within one pole of the rotor punching sheet in Figure 1 ;

[0034] Figure 3 is Figure 1 a partial structure amplification within one pole of the rotor punching sheet in Figure 2 ;

[0035] Figure 4 is an effect diagram of the permanent magnet magnetic density optimization of the rotor punching sheet of the present invention compared with the prior art;

[0036] Figures 5a - 5b is an effect diagram of the back electromotive force harmonic optimization of the present invention compared with the prior art;

[0037] Figure 6 is a structural schematic diagram of the magnetic isolation bridge part of the rotor punching sheet of the present invention.

[0038] The reference numerals are shown as:

[0039] A, punching sheet main body; B, permanent magnet slot; C, permanent magnet; D, weight reduction slot; E, rotor shaft hole;

[0040] B1, Inner permanent magnet slot; B2, Outer permanent magnet slot; B11, Inner first permanent magnet slot; B12, Inner second permanent magnet slot; B21, Outer first permanent magnet slot; B22, Outer second permanent magnet slot; d-axis, Magnetic pole center line; L, Center line of inner permanent magnet slot; dl, Distance between d-axis and L;

[0041] B111, First arc edge; B121, Second arc edge; R, Rotor punching radius; R1, Radius of the first arc edge; R2, Radius of the second arc edge;

[0042] a, Inner magnetic isolation bridge; b, Outer magnetic isolation bridge; da, Width of inner magnetic isolation bridge; db, Width of outer magnetic isolation bridge. Detailed implementation manners

[0043] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0044] It should be noted that the terms used here are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present application. As used here, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or their combinations.

[0045] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps described in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that for the convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the said technologies, methods, and devices should be regarded as part of the authorized specification. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0046] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by orientation words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom", etc. is usually based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description. Without contrary explanation, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of the present invention; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0047] For convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above" etc. may be used here to describe the spatial positional relationship of one device or feature to another device or feature as shown in the drawings. It should be understood that the spatial relative terms are intended to cover different orientations in use or operation in addition to the orientation depicted in the drawings of the device. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the corresponding explanations for the spatial relative descriptions used here will be made.

[0048] In addition, it should be noted that the use of words such as "first", "second" to limit components is only for the convenience of distinguishing the corresponding components. Without additional statement, the above words have no special meaning. Therefore, it should not be construed as a limitation on the protection scope of the present invention.

[0049] As Figures 1 - 6 shown, the present invention provides a rotor punching sheet, which comprises:

[0050] The punching sheet body A and the permanent magnet slots B, the permanent magnet slots B are arranged on the punching sheet body A, the permanent magnet slots B include an inner permanent magnet slot B1 and an outer permanent magnet slot B2. Along the radial direction of the rotor punching sheet, the outer permanent magnet slot B2 is located outside the inner permanent magnet slot B1. The punching sheet body A has a d-axis. The outer permanent magnet slot B2 includes an outer first permanent magnet slot B21 and an outer second permanent magnet slot B22. The outer first permanent magnet slot B21 is located on one side of the d-axis (preferably on one side of the d-axis along the circumferential direction of the rotor punching sheet), and the outer second permanent magnet slot B22 is located on the other side of the d-axis (preferably on the other side of the d-axis along the circumferential direction of the rotor punching sheet), and the outer first permanent magnet slot B21 and the outer second permanent magnet slot B22 are symmetrical with respect to the d-axis;

[0051] The punching sheet body A also has an inner permanent magnet slot center line L, and the L is parallel to the d-axis and spaced apart by a preset distance greater than 0. The inner permanent magnet slot B1 includes an inner first permanent magnet slot B11 located on one side of the L and an inner second permanent magnet slot B12 located on the other side of the L (preferably located on both sides of the L along the circumferential direction of the rotor punching sheet), and the inner first permanent magnet slot B11 and the inner second permanent magnet slot B12 have the same shape and area size. The minimum distance between the inner first permanent magnet slot B11 and the L and the minimum distance between the inner second permanent magnet slot B12 and the L are equal, but the inner first permanent magnet slot B11 and the inner second permanent magnet slot B12 are not symmetrical with respect to the L.

[0052] In the present invention, the permanent magnet slots on the rotor punching sheet are divided into inner and outer permanent magnet slots. The outer permanent magnet slot includes an outer first and an outer second permanent magnet slot symmetrically arranged with respect to the d-axis. The inner permanent magnet slot includes an inner first permanent magnet slot and an inner second permanent magnet slot. The inner first and inner second permanent magnet slots have the same size and shape, and the two are not symmetrically arranged with respect to the center line L. The center line L is a line parallel and offset from the d-axis. Thus, the outer permanent magnet slot B2 is symmetric about the magnetic pole center line d like a traditional rotor punching sheet, while the inner permanent magnet slot B1 is asymmetric about the d-axis, and the inner permanent magnet slot B1 forms a staggered symmetry about the center line L. Different from the traditional rotor punching sheet, the asymmetric rotor structure of the present invention can reduce the magnetic leakage between magnetic poles, increase the air-gap magnetic density, enhance the fundamental wave content, obtain an air-gap waveform with better sinusoidality, improve the harmonic distortion rate, reduce and improve harmonics, and at the same time has a significant effect on suppressing the cogging torque.

[0053] In view of the problems of poor demagnetization performance, high cogging torque and high harmonic content of the existing structural punching sheets for motors, the present invention proposes an asymmetric rotor punching sheet with a single pole asymmetric about the d-axis, and multi-objective optimization is carried out with the anti-demagnetization performance and harmonic content as the optimization objectives. Finally, the asymmetric rotor punching sheet structure of this proposal is obtained, which improves the reliability of the motor, effectively improves the sinusoidality of the air-gap magnetic field, reduces harmonics, weakens the cogging torque of the motor, and improves the demagnetization performance on the basis of ensuring the output torque of the motor, so as to achieve high performance and high efficiency. On the premise of ensuring that the average torque remains basically unchanged, the anti-demagnetization performance of the optimized motor scheme is improved by 35%, and the harmonic content of the back electromotive force is reduced by 33%, as Figures 5a - 5b shown.

[0054] In some embodiments,

[0055] Relatively, the inner-layer first permanent magnet slot B11 is arranged relatively close to the outer circumferential surface of the rotor punching sheet, the inner-layer second permanent magnet slot B12 is arranged relatively far from the outer circumferential surface of the rotor punching sheet, and the minimum distance between the inner-layer first permanent magnet slot B11 and the outer circumferential surface is larger than the minimum distance between the inner-layer second permanent magnet slot B12 and the outer circumferential surface.

[0056] This is the preferred positional relationship between the two permanent magnet slots in the inner layer of the present invention, that is, the inner-layer first permanent magnet slot is relatively close to the outer circle of the rotor, the inner-layer second permanent magnet slot is relatively close to the shaft hole of the rotor, and the distances between the inner-layer first permanent magnet slot and the inner-layer second permanent magnet slot and L are equal respectively, thus forming a misaligned symmetric structure of the two permanent magnet slots in the inner layer. Therefore, the magnetic leakage between magnetic poles can be reduced, the air-gap magnetic density can be increased, the fundamental wave content can be enhanced, an air-gap waveform with better sinusoidality can be obtained, the harmonic distortion rate can be improved, and at the same time, it has a significant effect on suppressing the cogging torque.

[0057] In some embodiments,

[0058] The distance between L and the d-axis is d1, and there is: d1 = 1.2 - 1.6 mm.

[0059] The present invention also sets the distance d1 between L and the d-axis to satisfy d1 = 1.2 - 1.6 mm. This constraint relationship can effectively reduce the magnetic leakage between poles, reduce the demagnetization risk at the sharp corners of the permanent magnet, increase the high magnetic density area on the permanent magnet, improve the anti-demagnetization performance of the permanent magnet, expand the high magnetic density area on the permanent magnet, increase the magnetic density in the easily demagnetized area at the sharp corners of the permanent magnet, and greatly reduce the demagnetization risk of the permanent magnet without affecting the main magnetic circuit.

[0060] In some embodiments,

[0061] When the motor rotates clockwise, the inner permanent magnet slot B1 is biased towards the clockwise side of the d-axis, that is, L is located at a position where the d-axis is translated by d1 in the clockwise direction;

[0062] When the motor rotates counterclockwise, the inner permanent magnet slot B1 is biased towards the counterclockwise side of the d-axis, that is, L is located at a position where the d-axis is translated by d1 in the counterclockwise direction.

[0063] The present invention also sets the rotor punching sheet such that when the motor rotates clockwise, the inner permanent magnet slot is biased towards the clockwise side of the d-axis, that is, L is located at a position where the d-axis is translated by d1 in the clockwise direction; when the motor rotates counterclockwise, the inner permanent magnet slot is biased towards the counterclockwise side of the d-axis, that is, L is located at a position where the d-axis is translated by d1 in the counterclockwise direction; it can make the output torque of the motor remain basically unchanged after the inner permanent magnet is offset, and the magnetic field line distribution is optimized, and the cogging torque and harmonic content are reduced.

[0064] In some embodiments,

[0065] The inner first permanent magnet slot B11 is located on the counterclockwise side of L, and the inner second permanent magnet slot B12 is located on the clockwise side of L;

[0066] When the motor rotates clockwise, the minimum distance between the inner first permanent magnet slot B11 and the d-axis is less than the minimum distance between the inner second permanent magnet slot B12 and the d-axis;

[0067] When the motor rotates counterclockwise, the minimum distance between the inner first permanent magnet slot B11 and the d-axis is greater than the minimum distance between the inner second permanent magnet slot B12 and the d-axis.

[0068] This is the relative position relationship between the inner first permanent magnet slot and the inner second permanent magnet slot of the present invention and L, so that when the motor rotates clockwise, L is located at a position where the d-axis is translated by d1 in the clockwise direction, and when the motor rotates counterclockwise, L is located at a position where the d-axis is translated by d1 in the counterclockwise direction. This embodiment preferably uses a counterclockwise rotating motor. Therefore, the inner permanent magnet slot B1 is biased towards the counterclockwise side of the d-axis, that is, L is on the left side of the d-axis, which can make the output torque of the motor remain basically unchanged after the inner permanent magnet is offset, and the magnetic field line distribution is optimized, and the cogging torque and harmonic content are reduced.

[0069] In some embodiments,

[0070] Along the radial direction of the rotor punching sheet, the outermost side of the inner layer first permanent magnet slot B11 is the first arc edge B111, and the outermost side of the inner layer second permanent magnet slot B12 is the second arc edge B121. The center of the first arc edge B111 coincides with the center point O of the shaft hole of the rotor punching sheet, and the center of the second arc edge B121 coincides with the center point O of the shaft hole of the rotor punching sheet. The radius of the first arc edge B111 is R1, the radius of the second arc edge B121 is R2, and the radius of the rotor punching sheet is R. Among them, there is a constraint relationship: R2 = R1 - (-0.1 to 0.15) mm, and R1 = R - (0.8 to 1.2) mm.

[0071] The present invention also forms the outermost side of the inner layer permanent magnet slot by the first arc edge B111 and the second arc edge B121. The centers of the first arc edge B111 and the second arc edge B121 coincide with the center point O of the rotor shaft hole. The radius of the first arc edge B111 is R1, the radius of the second arc edge B121 is R2, and the radius of the rotor punching sheet is R. Among them, there is a constraint relationship: R2 = R1 - (-0.1 to 0.15) mm, and R1 = R - (0.8 to 1.2) mm. This constraint relationship forms magnetic isolation bridges between the first arc edge B111 and the second arc edge B121 and the outer edge of the rotor respectively, and ensures that the width difference between the two magnetic isolation bridges is small, so that the inner layer permanent magnet slot forms a staggered symmetric structure with respect to the straight line L. The motor with this staggered symmetric structure can effectively alleviate the high-order harmonic phenomenon after optimization design. The fundamental wave amplitude is greatly increased, and the waveform is closer to a sine wave, which can effectively weaken the cogging torque. At the same time, it prevents serious magnetic leakage caused by too large magnetic isolation bridges on both sides, resulting in a reduction in the electromagnetic performance of the motor, and too small magnetic isolation bridges on the rotor causing stress concentration problems and a reduction in the strength of the rotor. Meeting this constraint relationship can ensure the optimal output torque performance of the motor and meet the requirements of the rotor strength.

[0072] In some embodiments,

[0073] Along the radial direction of the rotor punching sheet, the inner end of the inner layer first permanent magnet slot B11 and the inner end of the inner layer second permanent magnet slot B12 are opposite in the circumferential direction of the rotor punching sheet, and the interval position between them forms an inner layer magnetic isolation bridge a. The width of the inner layer magnetic isolation bridge a in the circumferential direction of the rotor punching sheet is da. Along the radial direction of the rotor punching sheet, the inner end of the outer layer first permanent magnet slot B21 and the inner end of the outer layer second permanent magnet slot B22 are opposite in the circumferential direction of the rotor punching sheet, and the interval position between them forms an outer layer magnetic isolation bridge b. The width of the outer layer magnetic isolation bridge a in the circumferential direction of the rotor punching sheet is db. Among them, there is a constraint relationship: db = 0.8 to 1.8 mm, da = (1.5 to 2) db, and d1 = da - db.

[0074] The inner magnetic isolation bridge a of the present invention is formed at the near-axis hole end of the inner permanent magnet slot B1. The circumferential width of the inner magnetic isolation bridge a is da. The outer magnetic isolation bridge b is formed at the near-axis hole end of the outer permanent magnet slot B2. The circumferential width of the outer magnetic isolation bridge b is db. Among them, there is a constraint relationship: db = 0.8 - 1.8 mm, da = (1.5 - 2)db, d1 = da - db. This constraint relationship can effectively reduce the magnetic leakage between poles without affecting the main magnetic circuit, reduce the demagnetization risk at the sharp corners of the permanent magnet, increase the high magnetic density region on the permanent magnet, and improve the demagnetization resistance performance of the permanent magnet. As Figure 4 shown Figure 4 is the cloud map of the magnetic flux density distribution on the permanent magnet. It can be seen from the figure that the rotor structure of the proposed invention expands the high magnetic density region on the permanent magnet, increases the magnetic density in the easy demagnetization region at the sharp corners of the permanent magnet, and greatly reduces the demagnetization risk of the permanent magnet.

[0075] The present invention also provides a rotor core, which includes the aforementioned rotor punching sheet, and multiple layers of rotor punching sheets are stacked to form the rotor core.

[0076] The present invention also provides a rotor, which includes the aforementioned rotor core and also includes a permanent magnet, and the permanent magnet is arranged in the permanent magnet slot B.

[0077] Figure 1 is the rotor punching sheet of the present invention. The rotor includes a rotor punching sheet and a permanent magnet C. The rotor punching sheet includes a punching sheet main body A, a permanent magnet slot B, a weight reduction slot D, a shaft hole E, etc. The permanent magnet C is inserted into the permanent magnet slot B. The permanent magnet slots and the weight reduction slots are evenly and spaced circumferentially on the rotor punching sheet.

[0078] The present invention proposes an asymmetric rotor punching sheet for the d-axis, and multi-objective optimization is carried out with the demagnetization performance and harmonic content as the optimization objectives. Finally, the structure of the proposed asymmetric rotor punching sheet is obtained. Under the premise of ensuring that the average torque remains basically unchanged, the demagnetization resistance performance of the optimized motor scheme is greatly improved, and the harmonic content and cogging torque are reduced.

[0079] It can solve the following technical problems:

[0080] 1. By optimizing the position and size of the permanent magnet slots on the inner rotor punching sheet, the magnetic field line distribution is improved, the demagnetization resistance performance of the motor is enhanced, and the harmonic content of the motor is reduced.

[0081] 2. By optimizing the cooperation of the inner and outer permanent magnet slots, while ensuring the electromagnetic performance, the magnetic field line distribution is optimized, and the harmonic content and cogging torque are reduced.

[0082] The present invention also provides a motor, which includes the aforementioned rotor.

[0083] In view of the problems of poor demagnetization performance, high cogging torque and high harmonic content of the existing structural punching sheet for motors, the present invention proposes an asymmetric rotor punching sheet for a single pole with respect to the d-axis. Multi-objective optimization is carried out with the anti-demagnetization performance and harmonic content as the optimization objectives. Finally, the asymmetric rotor punching sheet structure of this proposal is obtained. On the basis of ensuring the motor output torque, the reliability of the motor is improved, the sinusoidality of the air-gap magnetic field is effectively improved, the harmonics are reduced, the cogging torque of the motor is weakened, and the demagnetization performance is improved, so as to achieve high performance and high efficiency. Under the premise of ensuring that the average torque remains basically unchanged, the anti-demagnetization performance of the optimized motor scheme is improved by 35%, and the harmonic content of the back electromotive force is reduced by 33%.

[0084] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A rotor punching, characterized in that: include: A punching sheet body (A) and a permanent magnet slot (B), wherein the permanent magnet slot (B) is arranged on the punching sheet body (A), the permanent magnet slot (B) comprises an inner layer permanent magnet slot (B1) and an outer layer permanent magnet slot (B2), and along the radial direction of the rotor punching sheet, the outer layer permanent magnet slot (B2) is located outside the inner layer permanent magnet slot (B1), the punching sheet body (A) has a d-axis, the outer layer permanent magnet slot (B2) comprises an outer layer first permanent magnet slot (B21) and an outer layer second permanent magnet slot (B22), the outer layer first permanent magnet slot (B21) is located on one side of the d-axis, the outer layer second permanent magnet slot (B22) is located on the other side of the d-axis, and the outer layer first permanent magnet slot (B21) and the outer layer second permanent magnet slot (B22) are symmetrical relative to the d-axis; The punching sheet body (A) also has an inner layer permanent magnet slot center line L, which is parallel to the d-axis and spaced at a preset distance greater than 0; the inner layer permanent magnet slot (B1) includes an inner layer first permanent magnet slot (B11) located on one side of the L, and an inner layer second permanent magnet slot (B12) located on the other side of the L, and the inner layer first permanent magnet slot (B11) and the inner layer second permanent magnet slot (B12) are the same in shape and area, the minimum spacing between the inner layer first permanent magnet slot (B11) and the L, and the minimum spacing between the inner layer second permanent magnet slot (B12) and the L are equal, but the inner layer first permanent magnet slot (B11) and the inner layer second permanent magnet slot (B12) are asymmetric relative to the L.

2. The rotor punching according to claim 1, characterized in that: Relatively speaking, the inner first permanent magnet slot (B11) is arranged relatively close to the outer circumferential surface of the rotor punching sheet, and the inner second permanent magnet slot (B12) is arranged relatively far away from the outer circumferential surface of the rotor punching sheet, and the minimum distance between the inner first permanent magnet slot (B11) and the outer circumferential surface is larger than the minimum distance between the inner second permanent magnet slot (B12) and the outer circumferential surface.

3. The rotor punching according to claim 1, characterized in that: The distance between the center line L of the inner permanent magnet slot and the d-axis is d1, and d1=1.2-1.6 mm.

4. The rotor punching according to claim 1, characterized in that: When the motor rotates clockwise, the inner permanent magnet slot (B1) is biased toward the clockwise side of the d-axis, that is, the L is located at a position where the d-axis is translated by d1 in the clockwise direction; When the motor rotates counterclockwise, the inner permanent magnet slot (B1) is biased toward the counterclockwise side of the d-axis, that is, L is located at a position where the d-axis is translated d1 in the counterclockwise direction.

5. The rotor punching according to claim 4, characterized in that: The inner first permanent magnet slot (B11) is located on one side of the L in the counterclockwise direction, and the inner second permanent magnet slot (B12) is located on one side of the L in the clockwise direction; When the motor rotates clockwise, the minimum distance between the inner first permanent magnet slot (B11) and the d-axis is smaller than the minimum distance between the inner second permanent magnet slot (B12) and the d-axis; When the motor rotates counterclockwise, the minimum distance between the inner first permanent magnet slot (B11) and the d-axis is greater than the minimum distance between the inner second permanent magnet slot (B12) and the d-axis.

6. The rotor punching according to any one of claims 1 to 5, characterized in that: Along the radial direction of the rotor punching sheet, the outermost edge of the inner first permanent magnet slot (B11) is the first arc edge (B111), and the outermost edge of the inner second permanent magnet slot (B12) is the second arc edge (B121). The center of the first arc edge (B111) coincides with the center point O of the axial hole of the rotor punching sheet, and the center of the second arc edge (B121) coincides with the center point O of the axial hole of the rotor punching sheet. The radius of the first arc edge (B111) is R1, the radius of the second arc edge (B121) is R2, and the radius of the rotor punching sheet is R, wherein there is a constraint relationship: R2=R1-(-0.1~0.15)mm, R1=R-(0.8~1.2)mm.

7. The rotor punching according to any one of claims 1 to 6, characterized in that: Along the radial direction of the rotor punching, the inner end of the inner layer first permanent magnet slot (B11) and the inner end of the inner layer second permanent magnet slot (B12) are opposite to each other in the circumferential direction of the rotor punching, and the interval between the two forms an inner layer magnetic isolation bridge a, and the width of the inner layer magnetic isolation bridge a along the circumferential direction of the rotor punching is da. Along the radial direction of the rotor punching, the inner end of the outer layer first permanent magnet slot (B21) and the inner end of the outer layer second permanent magnet slot (B22) are opposite to each other in the circumferential direction of the rotor punching, and the interval between the two forms an outer layer magnetic isolation bridge b, and the width of the outer layer magnetic isolation bridge b along the circumferential direction of the rotor punching is db, wherein there is a constraint relationship: db = 0.8 ~ 1.8mm, da = (1.5 ~ 2)db, d1 = da-db.

8. A rotor core, characterized in that: The invention comprises the rotor punching sheet according to any one of claims 1 to 7, wherein multiple layers of rotor punching sheets are stacked to form a rotor core.

9. A rotor, characterized in that: The rotor core according to claim 8 further comprises a permanent magnet, wherein the permanent magnet is arranged in the permanent magnet slot (B).

10. A motor, characterized in that: Comprising the rotor as claimed in claim 9.

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