Rotor assembly, motor and vehicle

Abstract

This invention discloses a rotor assembly, a motor, and a vehicle. The rotor assembly includes a rotor core and multiple permanent magnet groups, which are evenly distributed along the circumference of the rotor core. Each permanent magnet group includes a first permanent magnet, a second permanent magnet, a third permanent magnet, and a fourth permanent magnet. The first, second, third, and fourth permanent magnets are sequentially spaced along the circumference of the rotor core. The first and fourth permanent magnets are symmetrical about the d-axis and are both rare-earth magnets, while the second and third permanent magnets are symmetrical about the d-axis and are both non-rare-earth magnets. On the same cross-section of the rotor core, the total area of ​​the rare-earth magnets in the multiple permanent magnet groups is S0, and the total area of ​​the multiple four-permanent-magnet groups is S... 总 The rotor assembly satisfies the following relationship: 40.7% ≤ S0 / S 总 ≤43.2%, or 45.9%≤S0 / S 总 ≤47.6%. This helps to reduce cogging torque and cost.

Description

Technical Field

[0001] This invention relates to the field of electric motors, and more particularly to a rotor assembly, an electric motor, and a vehicle. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in electric vehicles. As a core component of the electrical drive system, the motor's overall performance directly impacts the performance of the electric vehicle. Currently, there are still technical bottlenecks in the development of high overload capacity, demagnetized PMSMs for electric vehicles, including issues such as high cogging torque, high cost, poor load torque, and high eddy current losses, indicating room for improvement. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a rotor assembly with low cogging torque, good NVH performance, high magnet utilization, and low cost.

[0004] According to an embodiment of the present invention, a rotor assembly includes: a rotor core; a plurality of permanent magnet groups, wherein the plurality of permanent magnet groups are evenly distributed along the circumference of the rotor core; each permanent magnet group includes a first permanent magnet, a second permanent magnet, a third permanent magnet, and a fourth permanent magnet, wherein the first permanent magnet, the second permanent magnet, the third permanent magnet, and the fourth permanent magnet are sequentially spaced apart along the circumference of the rotor core; the first permanent magnet and the fourth permanent magnet are symmetrically arranged about the d-axis and are both rare-earth magnets; the second permanent magnet and the third permanent magnet are symmetrically arranged about the d-axis and are both non-rare-earth magnets; on the same cross-section of the rotor core, the total area of ​​the rare-earth magnets in the plurality of permanent magnet groups is S0, and the total area of ​​the plurality of permanent magnet groups is S... 总 The rotor assembly satisfies the following relationship: 40.7% ≤ S0 / S 总 ≤43.2%, or 45.9%≤S0 / S 总 ≤47.6%.

[0005] According to the rotor assembly of the present invention, by limiting the area ratio of rare earth magnets within a certain range, the cogging torque of the rotor assembly can be reduced, which is beneficial to reducing the overall cogging torque of the motor. This reduces the torque fluctuation caused by cogging torque, reduces the vibration problem caused by unstable motor output, improves the NVH performance of the motor, and increases the utilization rate of magnets. This reduces the cost of using permanent magnets compared to using only rare earth magnets, AlNiCo, and other materials, thus improving the overall performance of the motor and the reliability of the vehicle.

[0006] According to some embodiments of the rotor assembly of the present invention, the non-rare earth magnet material is ferrite magnet.

[0007] According to some embodiments of the rotor assembly of the present invention, the minimum distance between the first permanent magnet and the d-axis is L1, and the minimum distance between the second permanent magnet and the d-axis is L2, satisfying: 4:3≤L1 / L2≤2:1.

[0008] According to some embodiments of the present invention, each first permanent magnet includes two first sub-permanent magnets arranged circumferentially spaced along the rotor core, and each fourth permanent magnet includes two fourth sub-permanent magnets arranged circumferentially spaced along the rotor core.

[0009] According to some embodiments of the present invention, in the rotor assembly, the angle between the first permanent magnet closest to the d-axis and the d-axis ranges from 15° to 45°, and the angle between the second permanent magnet and the d-axis ranges from 5° to 30°.

[0010] According to some embodiments of the present invention, in a rotor assembly, on the same cross-section of the rotor core, a first permanent magnet and a second permanent magnet are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first permanent magnet closest to the d0 axis and the center of the rotor core is a first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet and the center of the rotor core is a second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the first permanent magnet is S1, and the area of ​​the third permanent magnet is S3. The rotor core satisfies the following relationship: 0.02*S1 ≤ ≤0.033*S1 .

[0011] According to some embodiments of the present invention, the rotor core of the rotor assembly satisfies the following relationship: 0.0201*S1 ≤ ≤0.022*S1 .

[0012] According to some embodiments of the present invention, in a rotor assembly, on the same cross-section of the rotor core, a first permanent magnet and a second permanent magnet are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first permanent magnet closest to the d0 axis to the center of the rotor core is a first line, and the angle between the first line and the d0 axis is α1. The line connecting the second permanent magnet to the center of the rotor core is a second line, and the angle between the second line and the d0 axis is α2. The area of ​​the second permanent magnet is S2, and the area of ​​the third permanent magnet is S3. The rotor core satisfies the following relationship: 0.0213*S2 ≤ ≤0.0222*S2 .

[0013] According to some embodiments of the present invention, the rotor core of the rotor assembly satisfies the following relationship: 0.0214*S2 ≤ ≤0.0216*S2 .

[0014] According to some embodiments of the present invention, in a rotor assembly, on the same cross-section of the rotor core, a first permanent magnet and a second permanent magnet are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first sub-permanent magnet closest to the d0 axis and the center of the rotor core is a first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet and the center of the rotor core is a second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the first sub-permanent magnet is S1, the area of ​​the fourth sub-permanent magnet is S4, and the rotor core satisfies the following relationship: 0.0213*S1 ≤ ≤0.0222*S1 .

[0015] According to some embodiments of the present invention, the rotor core of the rotor assembly satisfies the following relationship: 0.0214*S1 ≤ ≤0.0216*S1 .

[0016] According to some embodiments of the present invention, in a rotor assembly, on the same cross-section of the rotor core, a first permanent magnet and a second permanent magnet are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first sub-permanent magnet closest to the d0 axis and the center of the rotor core is a first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet and the center of the rotor core is a second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the second permanent magnet is S2, the area of ​​the fourth sub-permanent magnet is S4, and the rotor core satisfies the following relationship: 0.0148*S2 ≤ ≤0.0226*S2 .

[0017] According to some embodiments of the present invention, the rotor core of the rotor assembly satisfies the following relationship: 0.0197*S2 ≤ ≤0.0226*S2 .

[0018] According to some embodiments of the present invention, in a rotor assembly, on the same cross-section of the rotor core, a first permanent magnet and a second permanent magnet are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first permanent magnet closest to the d0 axis to the center of the rotor core is a first line, and the angle between the first line and the d0 axis is α1. The line connecting the second permanent magnet to the center of the rotor core is a second line, and the angle between the second line and the d0 axis is α2. The area of ​​the first permanent magnet is S1, the area of ​​the second permanent magnet is S2, and the area of ​​the third permanent magnet is S3. The rotor core satisfies the following relationship: 0.02*S1 ≤ ≤0.024*S2 .

[0019] According to some embodiments of the present invention, the rotor core of the rotor assembly satisfies the following relationship: 0.0201*S1 ≤ ≤0.0214*S2 .

[0020] According to some embodiments of the present invention, in a rotor assembly, on the same cross-section of the rotor core, a first permanent magnet and a second permanent magnet are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first sub-permanent magnet closest to the d0 axis to the center of the rotor core is a first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet to the center of the rotor core is a second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the first sub-permanent magnet is S1, the area of ​​the second permanent magnet is S2, and the area of ​​the fourth sub-permanent magnet is S4. The rotor core satisfies the following relationship: 0.021*S1 ≤ ≤0.023*S2 .

[0021] According to some embodiments of the present invention, the rotor core of the rotor assembly satisfies the following relationship: 0.0213*S1 ≤ ≤0.0226*S2 .

[0022] The present invention also proposes an electric motor.

[0023] The motor according to an embodiment of the present invention includes the rotor assembly described in any of the above embodiments.

[0024] According to the present invention, by limiting the area ratio of rare earth magnets within a certain range, the cogging torque of the rotor assembly can be reduced, which is beneficial to reducing the overall cogging torque of the motor. This reduces torque fluctuations caused by cogging torque, reduces vibration problems caused by unstable motor output, improves the NVH performance of the motor, and increases the utilization rate of magnets. This reduces the cost of using permanent magnets compared to using only rare earth magnets, AlNiCo, and other materials, thus improving the overall performance of the motor.

[0025] The present invention also proposes a vehicle.

[0026] The vehicle according to embodiments of the present invention includes the motor described in any of the above embodiments.

[0027] According to the vehicle of the present invention, by limiting the area ratio of rare earth magnets within a certain range, the cogging torque of the rotor assembly can be reduced, which is beneficial to reducing the overall cogging torque of the motor. This reduces the torque fluctuation caused by the cogging torque, reduces the vibration problem caused by the unstable output of the motor, improves the NVH performance of the motor, and can also improve the utilization rate of magnets. This reduces the cost of using permanent magnets compared to using only rare earth magnets, AlNiCo, and other materials, thus improving the overall performance of the motor and the reliability of the vehicle.

[0028] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0030] Figure 1 This is a schematic diagram of a rotor assembly according to an embodiment of the present invention;

[0031] Figure 2 This is a partial schematic diagram of the rotor core according to an embodiment of the present invention;

[0032] Figure 3 This is a partial schematic diagram of a rotor core according to another embodiment of the present invention;

[0033] Figure 4 This is a waveform diagram of the cogging torque when only neodymium iron boron magnets are used under the same conditions;

[0034] Figure 5 This is a waveform diagram of the cogging torque when using hybrid magnets under the same conditions;

[0035] Figure 6This is a graph showing the relationship between cogging torque and the area ratio of non-rare earth magnets when using hybrid magnets.

[0036] Figure label:

[0037] Rotor assembly 100,

[0038] Rotor core 1, first mounting slot 11, second mounting slot 12, third mounting slot 13, fourth mounting slot 14,

[0039] First permanent magnet 2, first sub-permanent magnet 21, second permanent magnet 3, third permanent magnet 4, fourth permanent magnet 5, fourth sub-permanent magnet 51. Detailed Implementation

[0040] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0041] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] Hereinafter, with reference to the accompanying drawings, a rotor assembly 100 according to an embodiment of the present invention will be described.

[0044] like Figures 1-2As shown, the rotor assembly 100 according to an embodiment of the present invention includes: a rotor core 1 and a plurality of permanent magnet groups, which are evenly distributed along the circumference of the rotor core 1; each permanent magnet group includes a first permanent magnet 2, a second permanent magnet 3, a third permanent magnet 4, and a fourth permanent magnet 5, which are sequentially spaced along the circumference of the rotor core 1; the first permanent magnet 2 and the fourth permanent magnet 5 are symmetrically arranged about the d-axis and are both rare earth magnets, and the second permanent magnet 3 and the third permanent magnet 4 are symmetrically arranged about the d-axis and are both non-rare earth magnets; on the same cross-section of the rotor core 1, the total area of ​​the rare earth magnets in the plurality of permanent magnet groups is S0, and the total area of ​​the plurality of permanent magnet groups is S... 总 The rotor assembly 100 satisfies the following relationship: 40.7% ≤ S0 / S 总 ≤43.2%, or 45.9%≤S0 / S 总 ≤47.6%.

[0045] Therefore, by limiting the area ratio of rare earth magnets to a certain range, the cogging torque of the rotor assembly can be reduced by 100%, which helps to reduce the overall cogging torque of the motor. This reduces torque fluctuations caused by cogging torque, reduces vibration caused by unstable motor output, improves the NVH performance of the motor, and increases the utilization rate of magnets. This reduces the cost of using permanent magnets compared to using only rare earth magnets (such as neodymium iron boron magnets) or AlNiCo materials.

[0046] Figure 4 This is a waveform diagram of the cogging torque when only neodymium iron boron magnets are used under the same conditions. The cogging torque is 158.5259 mNm. Figure 5 This is a waveform diagram of the cogging torque when using hybrid magnets under the same conditions. The cogging torque is 39.6127 mNm.

[0047] The simulation results show that, under the same conditions, the cogging torque of the hybrid magnet arrangement is reduced by 118.9132 mNm, or 75.01%, compared to using only rare earth magnets. This indicates that the hybrid magnet arrangement results in lower cogging torque and lower cost compared to using rare earth magnets (such as neodymium iron boron) alone.

[0048] For example, refer to Figures 1-3 As shown, the rotor assembly 100 includes a rotor core 1, which is ring-shaped and formed by stacking multiple silicon steel sheets sequentially along the axial direction. The rotor core 1 has multiple mounting slot groups, which are evenly spaced along the circumference of the rotor core 1. Each mounting slot group includes multiple mounting slots. The rotor assembly 100 has multiple permanent magnet groups, which are respectively installed into the mounting slot groups.

[0049] The mounting slot group includes a first mounting slot 11, a second mounting slot 12, a third mounting slot 13, and a fourth mounting slot 14. The first mounting slot 11, the second mounting slot 12, the third mounting slot 13, and the fourth mounting slot 14 are arranged sequentially and spaced apart along the circumference of the rotor core 1. Each permanent magnet group includes a first permanent magnet 2, a second permanent magnet 3, a third permanent magnet 4, and a fourth permanent magnet 5. The first permanent magnet 2 is installed in the first mounting slot 11, the second permanent magnet 3 is installed in the second mounting slot 12, the third permanent magnet 4 is installed in the third mounting slot 13, and the fourth permanent magnet 5 is installed in the fourth mounting slot 14, so that the first permanent magnet 2, the second permanent magnet 3, the third permanent magnet 4, and the fourth permanent magnet 5 can be sequentially and spaced apart along the circumference of the rotor core 1.

[0050] Simultaneously, the first permanent magnet 2 and the fourth permanent magnet 5 can be symmetrically arranged about the d-axis, and the second permanent magnet 3 and the third permanent magnet 4 can also be symmetrically arranged about the d-axis. The first permanent magnet 2 and the fourth permanent magnet 5 are made of rare-earth magnets, while the second permanent magnet 3 and the third permanent magnet 4 are made of non-rare-earth magnets. This allows the first permanent magnet 2, the second permanent magnet 3, the third permanent magnet 4, and the fourth permanent magnet 5 to form a hybrid permanent magnet group. It should be noted that non-rare-earth magnet materials are typically ferrite, AlNiCo, or other materials with lower costs than rare-earth magnets, and this does not limit the type of permanent magnet material to a specific permanent magnet group.

[0051] In the same cross-section of rotor core 1, the total area of ​​rare earth magnets in multiple permanent magnet groups is S0, and the total area of ​​multiple permanent magnet groups is S. 总 That is, the total area of ​​all permanent magnet groups is S. 总 The rotor assembly 100 satisfies the following relationship: 40.7% ≤ S0 / S 总 ≤43.2%, or 45.9%≤S0 / S 总 ≤47.6%.

[0052] In other words, the total area S0 of rare earth magnets and the total area S of multiple permanent magnet groups can be set. 总 The ratio is greater than or equal to 40.7% and less than or equal to 43.2%; alternatively, the total area S0 of rare earth magnets and the total area S of multiple permanent magnet groups can be set. 总 The ratio is greater than or equal to 45.9% and less than or equal to 47.6%, and this application does not impose any restrictions on this.

[0053] according to Figure 6As shown in the simulation curves, when the total area of ​​the magnets is constant, using a mixed arrangement of non-rare earth magnets and rare earth magnets, and when the proportion of rare earth magnets to the total magnet area is within the above range, can reduce the cogging torque of the rotor assembly by 100%, thereby reducing the overall cogging torque of the motor. This reduces torque fluctuations caused by cogging torque, reduces vibration problems caused by unstable motor output, improves the NVH performance of the motor, and increases the utilization rate of the magnets. This makes the cost of using magnets lower than when only rare earth materials, AlNiCo, and other materials are used.

[0054] It should be noted that at different times, when the rotor assembly 100 rotates to different positions, the operating point of the magnet is different, and the distribution of eddy current loss in the magnet produced by magnets of different areas and materials is time-varying. The eddy current loss of the magnet mentioned in this application refers to the "average value of the eddy current loss of the magnet".

[0055] In some embodiments of the present invention, the non-rare earth magnet material is ferrite magnet. Through the above-described configuration, the cost of the permanent magnet assembly can be effectively reduced, the demagnetization resistance of the permanent magnet assembly can be improved, and the practicality and reliability of the rotor assembly 100 can be enhanced.

[0056] In some embodiments of the present invention, the minimum distance between the first permanent magnet 2 and the d-axis is L1, and the minimum distance between the second permanent magnet 3 and the d-axis is L2, satisfying: 4:3≤L1 / L2≤2:1.

[0057] For example, refer to Figure 2 As shown, the minimum distance between the first permanent magnet 2 and the d-axis can be set as L1, and the minimum distance between the second permanent magnet 3 and the d-axis can be set as L2, satisfying: 4:3 ≤ L1 / L2 ≤ 2:1. That is, the ratio between the minimum distance L1 between the first permanent magnet 2 and the d-axis and the minimum distance L2 between the second permanent magnet 3 and the d-axis can be set to be greater than or equal to four-thirds and less than or equal to 2. Similarly, the third permanent magnet 4 and the fourth permanent magnet 5 are handled in the same way, and will not be repeated here. This improves the layout rationality of the rotor assembly 100 and enhances its reliability.

[0058] In some embodiments of the present invention, each first permanent magnet 2 includes two first sub-permanent magnets 21 arranged circumferentially spaced along the rotor core 1, and each fourth permanent magnet 5 includes two fourth sub-permanent magnets 51 arranged circumferentially spaced along the rotor core 1. For example, refer to Figure 2As shown, each first permanent magnet 2 can be configured to include two first sub-permanent magnets 21, which are arranged circumferentially around the rotor core 1. The fourth permanent magnet 5 can be configured to include two fourth sub-permanent magnets 51, which are arranged circumferentially around the rotor core 1. The first sub-permanent magnets 21 and the fourth sub-permanent magnets 51 are symmetrical about the d-axis.

[0059] Of course, in such Figure 3 In the embodiment shown, the second permanent magnet 3 may also include two second sub-permanent magnets, which are arranged circumferentially spaced along the rotor core 1, and the third permanent magnet 4 may include two third sub-permanent magnets, which are arranged circumferentially spaced along the rotor core 1, and the second and third sub-permanent magnets may be arranged symmetrically about the d-axis.

[0060] It should be noted that, according to the principle of superposition, the total cogging torque of each pole of the motor can be simplified to the superposition of the cogging torque generated by each segment of the permanent magnet, satisfying:

[0061]

[0062] In the formula: Ns is the number of segments of the permanent magnet; Tn is the cogging torque amplitude of the nth harmonic; Np is the number of cogging torque cycles per tooth pitch; Z is the number of slots; Δβ is the offset angle between two adjacent permanent magnet segments. The number of cogging torque cycles per tooth pitch is: Np = 2p / GCD(Z, 2p), where GCD(Z, 2p) represents the greatest common divisor of Z and 2p. From the above formula, it can be seen that by changing the number of segments Ns of the permanent magnet, the total cogging torque per pole can be effectively reduced.

[0063] Therefore, by setting the first permanent magnet 2 to include two spaced-apart first sub-permanent magnets 21 and the fourth permanent magnet 5 to include two spaced-apart fourth permanent magnets 5, the cogging torque of the rotor assembly 100 can be reduced, thus reducing the overall cogging torque of the motor. This reduces the torque fluctuation caused by the cogging torque, reduces the vibration problem caused by the unstable output of the motor, and improves the NVH performance of the motor.

[0064] In some embodiments of the present invention, the angle between the first permanent magnet 21 closest to the d-axis and the d-axis ranges from 15° to 45°, and the angle between the second permanent magnet 3 and the d-axis ranges from 5° to 30°.

[0065] For example, refer to Figure 2As shown, the angle between the first sub-permanent magnet 21 closest to the d-axis and the d-axis can be set to a range of 15°-45°. That is, the angle between the first sub-permanent magnet 21 closest to the d-axis and the d-axis can be 20°; or, the angle between the first sub-permanent magnet 21 closest to the d-axis and the d-axis can be 30°; or, the angle between the first sub-permanent magnet 21 closest to the d-axis and the d-axis can be 40°. This application does not impose any restrictions on this.

[0066] Meanwhile, the angle between the second permanent magnet 3 and the d-axis can be set to a range of 5°-30°. That is, the angle between the second permanent magnet 3 and the d-axis can be set to 10°; or, the angle between the second permanent magnet 3 and the d-axis and the d-axis can be set to 17.5°; or, the angle between the first sub-permanent magnet 21, which is closest to the d-axis, and the d-axis can be set to 25°. This application does not impose any restrictions on this. Similarly, the third permanent magnet 4 and the fourth permanent magnet 5 are described in the same way as above, and will not be repeated here.

[0067] The above settings allow for flexible adjustment of the number and position of permanent magnet groups on rotor core 1, which helps to meet different working conditions and improves the practicality of rotor assembly 100.

[0068] In some embodiments of the present invention, on the same cross-section of the rotor core 1, a first permanent magnet 2 and a second permanent magnet 3 are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first sub-permanent magnet 21 closest to the d0 axis and the center of the rotor core 1 is the first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet 3 and the center of the rotor core 1 is the second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the first sub-permanent magnet 21 is S1, the area of ​​the third permanent magnet 4 is S3, and the rotor assembly 100 satisfies the following relationship: 0.02*S1 ≤ ≤0.033*S1 .

[0069] For example, refer to Figure 2 As shown, on the same cross-section of the rotor core 1, the first permanent magnet 2 and the second permanent magnet 3 are respectively disposed on both sides of the d0 axis, and the minimum distance from the first permanent magnet 2 to the d0 axis is equal to the minimum distance from the second permanent magnet 3 to the d0 axis. The geometric center of the first sub-permanent magnet 21, which is closest to the d0 axis, is connected to the center of the rotor core 1 by a first connecting line, and the angle between the first connecting line and the d0 axis is set as α1. The second permanent magnet 3 is connected to the center of the rotor core 1 by a second connecting line, and the angle between the second connecting line and the d0 axis is set as α2. The area of ​​the first sub-permanent magnet 21 is set as S1, and the area of ​​the third permanent magnet 4 is set as S3.

[0070] The rotor assembly 100 satisfies the following relationship: 0.02*S1 ≤ ≤0.033*S1 In other words, the total area S of the first to fourth permanent magnets 5 总 The ratio between the area S3 of the third permanent magnet 4 and the area S1 of the first sub-permanent magnet 21 is greater than or equal to 0.02 times. The product of, and less than or equal to, 0.033 times the area S1 of the first sub-permanent magnet 21 multiplied by, The product of these parameters. By using the above settings, the cogging torque of the rotor assembly can be reduced by 100%, which helps to reduce the overall cogging torque of the motor. This reduces torque fluctuations caused by cogging torque, reduces vibration caused by unstable motor output, improves the NVH performance of the motor, and increases the utilization rate of magnets, which helps to reduce costs.

[0071] In a more preferred embodiment, the rotor assembly 100 satisfies the following relationship: 0.0201*S1 ≤ ≤0.022*S1 Its effect is more obvious than the above.

[0072] In some embodiments of the present invention, on the same cross-section of the rotor core 1, a first permanent magnet 2 and a second permanent magnet 3 are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first permanent magnet 21 closest to the d0 axis and the center of the rotor core 1 is the first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet 3 and the center of the rotor core 1 is the second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the second permanent magnet 3 is S2, the area of ​​the third permanent magnet 4 is S3, and the rotor assembly 100 satisfies the following relationship: 0.0213*S2 ≤ ≤0.0222*S2 .

[0073] For example, refer to Figure 2 As shown, on the same cross-section of the rotor core 1, the first permanent magnet 2 and the second permanent magnet 3 are respectively disposed on both sides of the d0 axis, and the minimum distance from the first permanent magnet 2 to the d0 axis is equal to the minimum distance from the second permanent magnet 3 to the d0 axis. The geometric center of the first permanent magnet 21 closest to the d0 axis is connected to the center of the rotor core 1 by a first connecting line, and the angle between the first connecting line and the d0 axis is set as α1. The second permanent magnet 3 is connected to the center of the rotor core 1 by a second connecting line, and the angle between the second connecting line and the d0 axis is set as α2. The area of ​​the second permanent magnet 3 is set as S2, and the area of ​​the third permanent magnet 4 is set as S3.

[0074] The rotor assembly 100 satisfies the following relationship: 0.0213*S2 ≤ ≤0.0222*S2 In other words, the total area S of the first to fourth permanent magnets 5 总 The ratio between the area S3 of the third permanent magnet 4 and the area S2 of the second permanent magnet 3 is greater than or equal to 0.0213 times. The product of, and less than or equal to, 0.0222 times the area S2 of the second permanent magnet 3. The product of these parameters. By using the above settings, the cogging torque of the rotor assembly can be reduced by 100%, which helps to reduce the overall cogging torque of the motor. This reduces torque fluctuations caused by cogging torque, reduces vibration caused by unstable motor output, improves the NVH performance of the motor, and increases the utilization rate of magnets, which helps to reduce costs.

[0075] In a more preferred embodiment, the rotor assembly 100 satisfies the following relationship: 0.0214*S2 ≤ ≤0.0216*S2 Its effect is more obvious than the above.

[0076] In some embodiments of the present invention, on the same cross-section of the rotor core 1, a first permanent magnet 2 and a second permanent magnet 3 are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first sub-permanent magnet 21 closest to the d0 axis and the center of the rotor core 1 is the first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet 3 and the center of the rotor core 1 is the second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the first sub-permanent magnet 21 is S1, the area of ​​the fourth sub-permanent magnet 51 is S4, and the rotor assembly 100 satisfies the following relationship: 0.0213*S1 ≤ ≤0.0222*S1 .

[0077] For example, refer to Figure 2 As shown, on the same cross-section of the rotor core 1, the first permanent magnet 2 and the second permanent magnet 3 are respectively located on both sides of the d0 axis, and the minimum distance from the first permanent magnet 2 to the d0 axis is equal to the minimum distance from the second permanent magnet 3 to the d0 axis. The geometric center of the first sub-permanent magnet 21, which is closest to the d0 axis, is connected to the center of the rotor core 1 by a first connecting line, and the angle between the first connecting line and the d0 axis is set as α1. The second permanent magnet 3 is connected to the center of the rotor core 1 by a second connecting line, and the angle between the second connecting line and the d0 axis is set as α2. The area of ​​the first sub-permanent magnet 21 can be set as S1, and the area of ​​the fourth sub-permanent magnet 51 can be set as S4.

[0078] The rotor assembly 100 satisfies the following relationship: 0.0213*S1 ≤ ≤0.0222*S1 In other words, the total area S of the first to fourth permanent magnets 5 总 The ratio between the area S4 of the fourth sub-permanent magnet 51 and the area S1 of the first sub-permanent magnet 21 is greater than or equal to 0.0213 times. The product of, and less than or equal to 0.0222 times the area S1 of the first sub-permanent magnet 21 multiplied by The product of these parameters. By using the above settings, the cogging torque of the rotor assembly can be reduced by 100%, which helps to reduce the overall cogging torque of the motor. This reduces torque fluctuations caused by cogging torque, reduces vibration caused by unstable motor output, improves the NVH performance of the motor, and increases the utilization rate of magnets, which helps to reduce costs.

[0079] In a more preferred embodiment, the rotor assembly 100 satisfies the following relationship: 0.0214*S1 ≤ ≤0.0216*S1 Its effect is more obvious than the above.

[0080] In some embodiments of the present invention, on the same cross-section of the rotor core 1, a first permanent magnet 2 and a second permanent magnet 3 are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first sub-permanent magnet 21 closest to the d0 axis and the center of the rotor core 1 is the first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet 3 and the center of the rotor core 1 is the second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the second permanent magnet 3 is S2, the area of ​​the fourth sub-permanent magnet 51 is S4, and the rotor assembly 100 satisfies the following relationship: 0.0148*S2 ≤ ≤0.0226*S2 .

[0081] For example, refer to Figure 2 As shown, on the same cross-section of the rotor core 1, the first permanent magnet 2 and the second permanent magnet 3 are respectively located on both sides of the d0 axis, and the minimum distance from the first permanent magnet 2 to the d0 axis is equal to the minimum distance from the second permanent magnet 3 to the d0 axis. The geometric center of the first sub-permanent magnet 21, which is closest to the d0 axis, is connected to the center of the rotor core 1 by a first connecting line, and the angle between the first connecting line and the d0 axis is set as α1. The second permanent magnet 3 is connected to the center of the rotor core 1 by a second connecting line, and the angle between the second connecting line and the d0 axis is set as α2. The area of ​​the second permanent magnet 3 can be set as S2, and the area of ​​the fourth sub-permanent magnet 51 can be set as S4.

[0082] The rotor assembly 100 satisfies the following relationship: 0.0148*S2 ≤ ≤0.0226*S2 In other words, the total area S of the first to fourth permanent magnets 5 总 The ratio between the area S4 of the fourth permanent magnet 51 and the area S2 of the second permanent magnet 3 is greater than or equal to 0.0148 times. The product of, and less than or equal to, 0.0226 times the area S2 of the second permanent magnet 3. The product of these parameters. By using the above settings, the cogging torque of the rotor assembly can be reduced by 100%, which helps to reduce the overall cogging torque of the motor. This reduces torque fluctuations caused by cogging torque, reduces vibration caused by unstable motor output, improves the NVH performance of the motor, and increases the utilization rate of magnets, which helps to reduce costs.

[0083] In a more preferred embodiment, the rotor assembly 100 satisfies the following relationship: 0.0197*S2 ≤ ≤0.0226*S2 Its effect is more obvious than the above.

[0084] In some embodiments of the present invention, on the same cross-section of the rotor core 1, a first permanent magnet 2 and a second permanent magnet 3 are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first sub-permanent magnet 21 closest to the d0 axis and the center of the rotor core 1 is the first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet 3 and the center of the rotor core 1 is the second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the first sub-permanent magnet 21 is S1, the area of ​​the second permanent magnet 3 is S2, and the area of ​​the third permanent magnet 4 is S3. The rotor assembly 100 satisfies the following relationship: 0.02*S1 ≤ ≤0.024*S2 .

[0085] For example, refer to Figure 2 As shown, on the same cross-section of the rotor core 1, the first permanent magnet 2 and the second permanent magnet 3 are respectively located on both sides of the d0 axis, and the minimum distance from the first permanent magnet 2 to the d0 axis is equal to the minimum distance from the second permanent magnet 3 to the d0 axis. The geometric center of the first sub-permanent magnet 21, which is closest to the d0 axis, is connected to the center of the rotor core 1 by a first connecting line, and the angle between the first connecting line and the d0 axis is set as α1. The second permanent magnet 3 is connected to the center of the rotor core 1 by a second connecting line, and the angle between the second connecting line and the d0 axis is set as α2. The area of ​​the first sub-permanent magnet 21 can be set as S1, the area of ​​the second permanent magnet 3 as S2, and the area of ​​the third permanent magnet 4 as S3.

[0086] The rotor assembly 100 satisfies the following relationship: 0.02*S1 ≤ ≤0.024*S2 In other words, the total area S of the first to fourth permanent magnets 5 总 The ratio between the area S3 of the third permanent magnet 4 and the area S1 of the first sub-permanent magnet 21 is greater than or equal to 0.02 times. The product of, and less than or equal to, 0.024 times the area S2 of the second permanent magnet 3. The product of these parameters. By using the above settings, the cogging torque of the rotor assembly can be reduced by 100%, which helps to reduce the overall cogging torque of the motor. This reduces torque fluctuations caused by cogging torque, reduces vibration caused by unstable motor output, improves the NVH performance of the motor, and increases the utilization rate of magnets, which helps to reduce costs.

[0087] In a more preferred embodiment, the rotor assembly 100 satisfies the following relationship: 0.0201*S1 ≤ ≤0.0214*S2 Its effect is more obvious than the above.

[0088] In some embodiments of the present invention, on the same cross-section of the rotor core 1, a first permanent magnet 2 and a second permanent magnet 3 are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first sub-permanent magnet 21 closest to the d0 axis and the center of the rotor core 1 is the first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet 3 and the center of the rotor core 1 is the second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the first sub-permanent magnet 21 is S1, the area of ​​the second permanent magnet 3 is S2, and the area of ​​the fourth sub-permanent magnet 51 is S4. The rotor assembly 100 satisfies the following relationship: 0.021*S1 ≤ ≤0.023*S2 .

[0089] For example, refer to Figure 2As shown, on the same cross-section of the rotor core 1, the first permanent magnet 2 and the second permanent magnet 3 are respectively located on both sides of the d0 axis, and the minimum distance from the first permanent magnet 2 to the d0 axis is equal to the minimum distance from the second permanent magnet 3 to the d0 axis. The geometric center of the first sub-permanent magnet 21, which is closest to the d0 axis, is connected to the center of the rotor core 1 by a first connecting line, and the angle between the first connecting line and the d0 axis is set as α1. The second permanent magnet 3 is connected to the center of the rotor core 1 by a second connecting line, and the angle between the second connecting line and the d0 axis is set as α2. The area of ​​the first sub-permanent magnet 21 can be set as S1, the area of ​​the second permanent magnet 3 as S2, and the area of ​​the fourth sub-permanent magnet 51 as S4.

[0090] The rotor assembly 100 satisfies the following relationship: 0.021*S1 ≤ ≤0.023*S2 In other words, the total area S of the first to fourth permanent magnets 5 can be set. 总 The ratio between the area S4 of the fourth sub-permanent magnet 51 and the area S1 of the first sub-permanent magnet 21 is greater than or equal to 0.021 times. The product of, and less than or equal to, 0.023 times the area S2 of the second permanent magnet 3. The product of these parameters. By using the above settings, the cogging torque of the rotor assembly can be reduced by 100%, which helps to reduce the overall cogging torque of the motor. This reduces torque fluctuations caused by cogging torque, reduces vibration caused by unstable motor output, improves the NVH performance of the motor, and increases the utilization rate of magnets, which helps to reduce costs.

[0091] In a more preferred embodiment, the rotor assembly 100 satisfies the following relationship: 0.0213*S1 ≤ ≤0.0226*S2 Its effect is more obvious than the above.

[0092] It should be noted that when multiple permanent magnet groups are installed on the rotor core 1, and the multiple permanent magnet groups include a first permanent magnet 2, a second permanent magnet 3, a third permanent magnet 4, and a fourth permanent magnet 5, and the first permanent magnet 2 includes two first sub-permanent magnets 21 arranged circumferentially spaced along the rotor core 1, and the fourth permanent magnet 5 includes two fourth sub-permanent magnets 51 arranged circumferentially spaced along the rotor core 1, if the following conditions are met simultaneously:

[0093] (1) 0.02*S1 ≤ ≤0.033*S1 ;

[0094] (2) 0.0213*S2 ≤ ≤0.0222*S2 ;

[0095] (3) 0.0213*S1 ≤ ≤0.0222*S1 ;

[0096] (4) 0.0148*S2 ≤ ≤0.0226*S2 ;

[0097] (5) 0.02*S1 ≤ ≤0.024*S2 ;

[0098] (6) 0.021*S1 ≤ ≤0.023*S2 .

[0099] Considering factors such as reduced cogging torque and cost, the motor has the best overall performance.

[0100] It should be noted that when S1, S2, S3, and S4 change, the cost, anti-demagnetization ability, load torque, and NVH performance of the permanent magnet will fluctuate. α1 and α2 affect the pole arc coefficient of the motor as the area of ​​the permanent magnet changes, thus affecting the load torque and NVH performance of the motor. The pole arc coefficient has an optimal range. When the above parameter relationship is satisfied, the pole arc coefficient is within the optimal range, the load torque and NVH performance of the motor are the best, and the cost is the lowest.

[0101] The present invention also proposes an electric motor.

[0102] The motor according to an embodiment of the present invention includes a rotor assembly 100 according to any of the above embodiments.

[0103] According to the present invention, by limiting the area ratio of rare earth magnets within a certain range, the cogging torque of the rotor assembly can be reduced by 100%, which helps to reduce the overall cogging torque of the motor, thereby reducing the torque fluctuation caused by cogging torque, reducing the vibration problem caused by unstable motor output, improving the NVH performance of the motor, and increasing the utilization rate of magnets. This reduces the cost of using permanent magnets compared to using only rare earth magnets (such as neodymium iron boron magnets), AlNiCo, etc., thus improving the overall performance of the motor.

[0104] The present invention also proposes a vehicle.

[0105] The vehicle according to an embodiment of the present invention includes a motor according to any of the above embodiments.

[0106] According to the vehicle of the present invention, by limiting the area ratio of rare earth magnets within a certain range, the cogging torque of the rotor assembly can be reduced by 100%, which is beneficial to reducing the overall cogging torque of the motor. This reduces the torque fluctuation caused by the cogging torque, reduces the vibration problem caused by the unstable output of the motor, improves the NVH performance of the motor, and can also improve the utilization rate of magnets. This reduces the cost of using permanent magnets compared to using only rare earth magnets (such as neodymium iron boron magnets), AlNiCo, etc., thus improving the overall performance of the motor and the reliability of the vehicle.

[0107] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0108] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A rotor assembly, characterized in that, include: Rotor core; Multiple permanent magnet groups are evenly distributed along the circumference of the rotor core. Each permanent magnet group includes a first permanent magnet, a second permanent magnet, a third permanent magnet, and a fourth permanent magnet. The first, second, third, and fourth permanent magnets are sequentially spaced along the circumference of the rotor core. The first and fourth permanent magnets are symmetrically arranged about the d-axis and are both rare-earth magnets. The second and third permanent magnets are symmetrically arranged about the d-axis and are both non-rare-earth magnets. On the same cross-section of the rotor core, the total area of ​​the rare-earth magnets in the multiple permanent magnet groups is S0, and the total area of ​​the multiple permanent magnet groups is S... 总 The rotor assembly satisfies the following relationship: 40.7% ≤ S0 / S 总 ≤43.2%, or 45.9%≤S0 / S 总 ≤47.6%.

2. The rotor assembly according to claim 1, characterized in that, The non-rare earth magnet material is ferrite magnet.

3. The rotor assembly according to claim 1, characterized in that, The minimum distance between the first permanent magnet and the d-axis is L1, and the minimum distance between the second permanent magnet and the d-axis is L2, satisfying: 4:3≤L1 / L2≤2:

1.

4. The rotor assembly according to any one of claims 1-3, characterized in that, Each of the first permanent magnets includes two first sub-permanent magnets arranged circumferentially spaced along the rotor core, and each of the fourth permanent magnets includes two fourth sub-permanent magnets arranged circumferentially spaced along the rotor core.

5. The rotor assembly according to claim 4, characterized in that, The angle between the first permanent magnet closest to the d-axis and the d-axis ranges from 15° to 45°, and the angle between the second permanent magnet and the d-axis ranges from 5° to 30°.

6. The rotor assembly according to claim 4, characterized in that, On the same cross-section of the rotor core, the first permanent magnet and the second permanent magnet are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first permanent magnet closest to the d0 axis and the center of the rotor core is the first line, and the angle between the first line and the d0 axis is α1. The line connecting the second permanent magnet and the center of the rotor core is the second line, and the angle between the second line and the d0 axis is α2. The area of ​​the first permanent magnet is S1, and the area of ​​the third permanent magnet is S3. The rotor assembly satisfies the following relationship: 0.02*S1 ≤ ≤0.033*S1 。 7. The rotor assembly according to claim 6, characterized in that, The rotor assembly satisfies the following relationship: 0.0201*S1 ≤ ≤0.022*S1 。 8. The rotor assembly according to claim 4, characterized in that, On the same cross-section of the rotor core, the first permanent magnet and the second permanent magnet are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first permanent magnet closest to the d0 axis to the center of the rotor core is the first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet to the center of the rotor core is the second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the second permanent magnet is S2, and the area of ​​the third permanent magnet is S3. The rotor assembly satisfies the following relationship: 0.0213*S2 ≤ ≤0.0222*S2 。 9. The rotor assembly according to claim 8, characterized in that, The rotor assembly satisfies the following relationship: 0.0214*S2 ≤ ≤0.0216*S2 。 10. The rotor assembly according to claim 4, characterized in that, On the same cross-section of the rotor core, the first permanent magnet and the second permanent magnet are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first sub-permanent magnet closest to the d0 axis and the center of the rotor core is the first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet and the center of the rotor core is the second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the first sub-permanent magnet is S1, and the area of ​​the fourth sub-permanent magnet is S4. The rotor assembly satisfies the following relationship: 0.0213*S1 ≤ ≤0.0222*S1 。 11. The rotor assembly according to claim 10, characterized in that, The rotor assembly satisfies the following relationship: 0.0214*S1 ≤ ≤0.0216*S1 。 12. The rotor assembly according to claim 4, characterized in that, On the same cross-section of the rotor core, the first permanent magnet and the second permanent magnet are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first sub-permanent magnet closest to the d0 axis and the center of the rotor core is the first connecting line, and the angle between the first connecting line and the d0 axis is α1. The line connecting the second permanent magnet and the center of the rotor core is the second connecting line, and the angle between the second connecting line and the d0 axis is α2. The area of ​​the second permanent magnet is S2, and the area of ​​the fourth sub-permanent magnet is S4. The rotor assembly satisfies the following relationship: 0.0148*S2 ≤ ≤0.0226*S2 。 13. The rotor assembly according to claim 12, characterized in that, The rotor assembly satisfies the following relationship: 0.0197*S2 ≤ ≤0.0226*S2 。 14. The rotor assembly according to claim 4, characterized in that, On the same cross-section of the rotor core, the first permanent magnet and the second permanent magnet are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first permanent magnet closest to the d0 axis to the center of the rotor core is the first line, and the angle between the first line and the d0 axis is α1. The line connecting the second permanent magnet to the center of the rotor core is the second line, and the angle between the second line and the d0 axis is α2. The area of ​​the first permanent magnet is S1, the area of ​​the second permanent magnet is S2, and the area of ​​the third permanent magnet is S3. The rotor assembly satisfies the following relationship: 0.02*S1 ≤ ≤0.024*S2 。 15. The rotor assembly according to claim 14, characterized in that, The rotor assembly satisfies the following relationship: 0.0201*S1 ≤ ≤0.0214*S2 。 16. The rotor assembly according to claim 4, characterized in that, On the same cross-section of the rotor core, the first permanent magnet and the second permanent magnet are respectively disposed on both sides of the d0 axis. The line connecting the geometric center of the first permanent magnet closest to the d0 axis to the center of the rotor core is the first line, and the angle between the first line and the d0 axis is α1. The line connecting the second permanent magnet to the center of the rotor core is the second line, and the angle between the second line and the d0 axis is α2. The area of ​​the first permanent magnet is S1, the area of ​​the second permanent magnet is S2, and the area of ​​the fourth permanent magnet is S4. The rotor assembly satisfies the following relationship: 0.021*S1 ≤ ≤0.023*S2 。 17. The rotor assembly according to claim 16, characterized in that, The rotor assembly satisfies the following relationship: 0.0213*S1 ≤ ≤0.0226*S2 。 18. An electric motor, characterized in that, Includes the rotor assembly according to any one of claims 1-17.

19. A vehicle, characterized in that, Includes the motor according to claim 18.

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