Rotor assembly for motor, motor and vehicle

Abstract

The invention discloses a rotor assembly for a motor, the motor and a vehicle. The rotor assembly comprises a rotor body, the rotor body is provided with p magnetic pole pairs, a first magnetic steel groove group and a second magnetic steel groove group which are sequentially arranged in the radial direction are formed in the rotor body, the first magnetic steel groove group comprises first magnetic steel grooves and second magnetic steel grooves, and in the first magnetic steel groove group, p magnetic pole pairs are arranged on the p magnetic pole pairs. The minimum central angle formed between the radial outer ends of the first magnetic steel grooves and the circle center of the rotor body and between the radial outer ends of the second magnetic steel grooves and the circle center of the rotor body is alpha 1, and alpha 1 = (k1 * 180 degrees) / p; the second magnetic steel groove group comprises a third magnetic steel groove and a fourth magnetic steel groove, in the second magnetic steel groove group, the minimum central angle formed between the radial outer end of the third magnetic steel groove and the radial outer end of the fourth magnetic steel groove and the circle center of the rotor body is alpha 2, and alpha 2 = (k2 * 180 degrees) / p; 0.3 < = k1 < = 0.35, and 0.55 < = k2 < = 0.65. The rotor assembly is provided with the alpha 1 and the alpha 2, so that magnetic field harmonic waves are reduced, and the output power and the electromagnetic performance of the motor are improved.

Description

Technical Field

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

[0002] The rotor structure of an electric motor affects its performance. At high speeds, magnetic field harmonics and magnetic flux density have a more pronounced impact on motor noise and other dynamic performance. Therefore, how to reduce motor vibration and noise through structural improvements to the rotor has become a pressing technical problem to be solved in this field. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of this invention is to provide a rotor assembly for an electric motor. The rotor assembly according to the invention, by arranging a third magnet slot, a first magnet slot, and a second magnet slot, increases the magnetic flux and magnetic flux density, thereby increasing the output power of the motor. Simultaneously, by rationally planning the position angles of the magnet slots using α1 and α2, magnetic field harmonics can be reduced, optimizing the electromagnetic performance and NVH performance of the motor.

[0004] The present invention also proposes a motor including the above-described rotor assembly.

[0005] The present invention also proposes a vehicle including the above-mentioned motor.

[0006] The rotor assembly according to the present invention includes a rotor body, the rotor body having p magnetic pole pairs, and a first magnetic slot group and a second magnetic slot group arranged sequentially in the radial direction on the rotor body. The first magnetic slot group includes a first magnetic slot and a second magnetic slot. In the first magnetic slot group, the minimum central angle formed between the radially outer ends of the first magnetic slot and the radially outer ends of the second magnetic slot and the center of the rotor body is α1, α1 = (k1 * 180°) / p. The second magnetic slot group includes a third magnetic slot and a fourth magnetic slot. In the second magnetic slot group, the minimum central angle formed between the radially outer ends of the third magnetic slot and the radially outer ends of the fourth magnetic slot and the center of the rotor body is α2, α2 = (k2 * 180°) / p; and satisfies: 0.3 ≤ k1 ≤ 0.35, 0.55 ≤ k2 ≤ 0.65.

[0007] By selecting appropriate values ​​for α1 and α2, the rotor assembly according to the present invention can balance parameters such as magnetic flux density, electromagnetic force and power factor of the motor, thereby achieving higher efficiency, greater output power and better dynamic performance of the motor; at the same time, appropriate values ​​for α1 and α2 can also effectively reduce magnetic field harmonics, thereby reducing motor vibration and noise and improving the motor's NVH performance.

[0008] According to one embodiment of the present invention, in the first magnet slot group, a gap is formed between the first magnet slot and the second magnet slot, and the gap gradually increases in the radially outward direction; in the second magnet slot group, a gap is formed between the third magnet slot and the fourth magnet slot, and the gap gradually increases in the radially outward direction.

[0009] According to one embodiment of the present invention, the rotor assembly further includes: a first magnet and a second magnet, the first magnet and the second magnet being respectively housed in a slot higher than the first magnet slot and the second magnet slot; in the cross-section of the rotor, the angle between the radially outer edge of the first magnet and the radially outer edge of the second magnet is α3, α3 = k3 * α1, and satisfies: 5 ≤ k3 ≤ 6; a third magnet and a fourth magnet, the third magnet and the fourth magnet being respectively housed in the slot of the third magnet and the slot of the fourth magnet; in the cross-section of the rotor, the angle between the radially outer edge of the third magnet and the radially outer edge of the fourth magnet is α4, α4 = k4 * α2, and satisfies: 2 ≤ k4 ≤ 3.

[0010] According to one embodiment of the present invention, k2 satisfies 0.58≤k2≤0.6; and k1 satisfies 0.32≤k1≤0.34.

[0011] According to one embodiment of the present invention, a rotor auxiliary groove is formed on the radially outer edge of the rotor body.

[0012] According to one embodiment of the present invention, the central angle formed by the two ends of the rotor auxiliary groove in the circumferential direction and the center of the rotor body is β, and satisfies: 1°≤β≤2°.

[0013] According to one embodiment of the present invention, the first magnet slot group and the second magnet slot group are respectively symmetrically arranged about the d-axis, and the angle between the straight line passing through the center of the auxiliary slot along the radial direction of the rotor body and the d-axis is γ and satisfies: 0.7*α2≤γ≤0.75*α2.

[0014] According to one embodiment of the present invention, the radial depth of the rotor auxiliary groove is L1 and satisfies: 0.3mm≤L1≤1mm.

[0015] According to one embodiment of the present invention, the rotor auxiliary groove is constructed as an arc groove.

[0016] According to one embodiment of the present invention, the second magnet slot group further includes a fifth magnet slot located between the third magnet slot and the fourth magnet slot, and there are multiple fifth magnet slots; the length of the magnet in the third magnet slot in the extension direction of the third magnet slot and the length of the magnet in the fourth magnet slot in the extension direction of the fourth magnet slot are both L2, and the length of the magnet in the fifth magnet slot is L3, satisfying: 1.9≤L2 / L3≤2.5.

[0017] According to one embodiment of the present invention, a first connecting portion is formed between two adjacent fifth magnet slots.

[0018] According to one embodiment of the present invention, the rotor body has a second connecting portion formed between the third magnet slot and the fifth magnet slot, and a third connecting portion formed between the fourth magnet slot and the fifth magnet slot.

[0019] The motor according to the present invention is briefly described below.

[0020] The motor according to the present invention includes the rotor assembly in the above embodiments. Since the motor according to the present invention is provided with the rotor assembly in the above embodiments, when the motor is equipped with the rotor assembly in the above embodiments, the output power of the motor can be increased by increasing the magnetic flux and magnetic flux density, and the electromagnetic performance and NVH performance of the motor can be optimized by reducing magnetic field harmonics, thereby improving the service life of the motor.

[0021] According to one embodiment of the present invention, the motor further includes: a stator disposed on the outer periphery of the rotor assembly, an air gap being formed between the stator and the rotor body, the air gap being d1 in the radial direction and satisfying: 1.5mm≤d1≤3mm.

[0022] According to one embodiment of the present invention, the stator is provided with a plurality of stator slots arranged at intervals in the circumferential direction, and flat wire windings are provided in the stator slots.

[0023] According to one embodiment of the present invention, the flat wire winding in each of the stator slots is constructed to have at least 10 layers.

[0024] According to one embodiment of the present invention, the inner circumference of the stator is provided with a plurality of teeth arranged at intervals in the circumferential direction, a stator groove is formed between two adjacent teeth, and at least one tooth is provided with a stator auxiliary groove recessed in the radial direction on the tooth tip facing the air gap side.

[0025] According to one embodiment of the present invention, the width of the stator auxiliary slot is d2, the tooth tip width of the tooth is d3, and satisfies: 1 / 3≤d2 / d3≤1 / 2.

[0026] According to one embodiment of the present invention, the stator auxiliary groove has a radial depth of d4, and satisfies: 0.1mm≤d4≤0.3mm.

[0027] According to one embodiment of the present invention, the rotor has N magnetic poles arranged circumferentially at intervals, and satisfies: 2≤N≤8, where N is an even number; the stator has N*M stator slots, and satisfies: M=3x, where x is a positive integer.

[0028] The vehicle according to the present invention is briefly described below.

[0029] The vehicle according to the present invention includes the motor in the above embodiments. Since the vehicle according to the present invention is equipped with the motor in the above embodiments, when the vehicle is equipped with the motor, the vehicle's power performance and NVH performance can be effectively improved. The motor has high reliability and service life, which can improve the vehicle's safety, while reducing the cost of replacing and repairing the vehicle's motor and improving the user experience of the vehicle.

[0030] 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

[0031] 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:

[0032] Figure 1 This is a structural diagram of a rotor assembly according to an embodiment of the present invention;

[0033] Figure 2 This is a structural diagram of a magnetic pole of a rotor assembly according to an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of a magnetic pole of a rotor assembly according to an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the structure of a magnetic pole of a rotor assembly according to an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram showing the relationship between a motor and a rotor assembly according to an embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram illustrating the relationship between a vehicle and a motor according to an embodiment of the present invention;

[0038] Figure 7 This is a diagram showing the relationship between the stress on the second connection (third connection) and L2 / L3;

[0039] Figure 8 This is a graph showing the relationship between torque pulsation rate and K1 and K2;

[0040] Figure 9 This is a graph showing the relationship between torque pulsation rate and K3 and K4;

[0041] Figure 10 This is a graph showing the relationship between torque pulsation rate and β;

[0042] Figure 11 This is a graph showing the relationship between torque pulsation rate and γ / α2;

[0043] Figure 12 This is a graph showing the relationship between the air gap width and the proportion of the magnet area;

[0044] Figure 13 This is a graph showing the relationship between the number of layers in a flat wire winding and eddy current losses.

[0045] Figure 14 This is a graph showing the relationship between the number of layers in a flat wire winding and its efficiency.

[0046] Figure 15 This is a graph showing the change in torque over time when the stator auxiliary slots are open or not.

[0047] Figure 16 This is a diagram showing the radial pressure variation at different orders when the stator has auxiliary slots open or closed;

[0048] Figure 17 This is a graph showing the changes in average torque and torque pulsation rate for different values ​​of d2 / d3;

[0049] Figure 18 This is a graph showing the relationship between air gap width and motor power attenuation.

[0050] Figure 19 This is a diagram showing the fit between a stator and a rotor body at a lower magnetic pole according to an embodiment of the present invention;

[0051] Figure 20 This is a partially enlarged view of the stator according to an embodiment of the present invention.

[0052] Figure label:

[0053] Rotor assembly 1;

[0054] Rotor body 11;

[0055] First magnet slot group 12, first magnet slot 121, first magnet 1211, second magnet slot 122, second magnet 1221;

[0056] Second magnet slot group 13, third magnet slot 131, third magnet 1311, fourth magnet slot 132, fourth magnet 1321, fifth magnet slot 133;

[0057] First connecting part 141, second connecting part 142, third connecting part 143;

[0058] Rotor auxiliary slot 15;

[0059] Motor 20;

[0060] Stator 21, gear 211, stator slot 212, stator auxiliary slot 213;

[0061] Weight reduction hole 223;

[0062] 23. Air gap, 24. Flat wire winding, 30. Vehicle. Detailed Implementation

[0063] 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.

[0064] The rotor structure of an electric motor affects its performance. At high speeds, magnetic field harmonics and magnetic flux density have a more pronounced impact on motor noise and other dynamic performance. Therefore, how to reduce motor vibration and noise through structural improvements to the rotor has become a pressing technical problem to be solved in this field.

[0065] The following is for reference. Figures 1-6 A rotor assembly according to an embodiment of the present invention is described.

[0066] The rotor assembly 1 according to the present invention includes a rotor body 11, the rotor body 11 having p magnetic pole pairs, and a first magnetic slot group 12 and a second magnetic slot group 13 arranged sequentially in the radial direction on the rotor body 11. The first magnetic slot group 12 includes a first magnetic slot 121 and a second magnetic slot 122. In the first magnetic slot group, the minimum distance formed between the radially outer ends of the first magnetic slot 121 and the radially outer ends of the second magnetic slot 122 and the center of the rotor body 11 is... The central angle is α1, α1=(k1*180°) / p; the second magnetic slot group 13 includes a third magnetic slot 131 and a fourth magnetic slot 132. In the second magnetic slot group, the minimum central angle formed between the radial outer end of the third magnetic slot 131 and the radial outer end of the fourth magnetic slot 132 and the center of the rotor body 11 is α2, α2=(k2*180°) / p; and satisfies: 0.3≤k1≤0.35, 0.55≤k2≤0.65.

[0067] According to the present invention, the rotor assembly 1 includes a rotor body 11, on which a first magnet slot group 12 and a second magnet slot group 13 arranged radially are machined. Each magnet slot group contains different magnet slots, and the number of different magnet slots is not limited. The specific distribution can be determined according to the actual magnetic flux requirements. For example, the first magnet slot group 12 can contain a first magnet slot 121 and a second magnet slot 122; the second magnet slot group 13 can contain a third magnet slot 131 and a fourth magnet slot 132. Each magnet slot can accommodate a corresponding magnet.

[0068] like Figure 1 and Figure 2 As shown, the rotor body 11 is provided with P magnetic pole pairs. One magnetic pole pair can be understood as having two magnetic poles. For any magnetic pole, the position of the magnetic steel slots can be reasonably planned to optimize the electromagnetic performance of the motor 20. Specifically, in the first magnetic steel slot group 12, the minimum central angle formed between the radial outer end of the first magnetic steel slot 121 and the radial outer end of the second magnetic steel slot 122 and the rotor center is the first pole arc angle, which can be represented by α1. α1 satisfies: α1=(k1*180°) / p, where 0.3≤k1≤0.35. For example, if P=3, that is, when the rotor body 11 has 3 magnetic pole pairs, α1=k1*60°, that is, 18°≤α1≤21°. Preferably, k1=0.33, in which case α1=19.8°. Similarly, in the second magnet slot group 13, the smallest central angle formed between the radial outer end of the third magnet slot 131 and the radial outer end of the fourth magnet slot 132 and the rotor center is the second pole arc angle, which can be represented by α2, and α2 satisfies: α2=(k2*180°) / p, where 0.55≤k2≤0.65. For example, if P=3, that is, when the rotor body 11 has 3 magnetic pole pairs, α2=k2*60°, that is, 33°≤α1≤39°, where, preferably, k1=0.59, at this time, α1=35.4°.

[0069] In the above scheme, during actual processing, k1 and k2 need to be determined to a reasonable value according to actual needs. This can be understood as the design of the first pole arc angle α1 and the second pole arc angle α2 fixing the values ​​of the pole arc angles, which helps to achieve a more stable and consistent magnetic field distribution, enabling the motor 20 to operate efficiently and smoothly. By selecting appropriate values ​​for α1 and α2, parameters such as magnetic flux density, electromagnetic force, and power factor of the motor 20 can be balanced, thereby achieving higher efficiency, greater output power, and better dynamic performance. Appropriate α1 and α2 can also effectively reduce magnetic field harmonics, thereby reducing the vibration and noise of the motor 20 and improving its NVH performance. Furthermore, fixing the values ​​of α1 and α2 in the production of the motor 20 simplifies the production process and manufacturing flow, reduces manufacturing costs, and also helps to ensure product consistency and reliability.

[0070] like Figure 8 As shown, Figure 8 The figure shows the relationship between torque ripple rate and k1 and k2. It is easy to see from the figure that when "0.3≤k1≤0.35, 0.55≤k2≤0.65", the torque ripple rate is less than 2%. Therefore, the values ​​of α1 and α2 are in a suitable range under this condition, which helps to suppress the harmonic content of the magnetic field, improve the NVH performance of the motor, and thus reduce the vibration and noise of the motor.

[0071] In some embodiments, magnetic isolation bridges may be provided between the first magnetic slot 121 and the radial outer edge of the rotor, between the second magnetic slot 122 and the radial outer edge of the rotor, between the third magnetic slot 131 and the radial outer edge of the rotor, and between the fourth magnetic slot 132 and the radial outer edge of the rotor.

[0072] According to one embodiment of the present invention, in the first magnet slot group 12, a gap is formed between the first magnet slot 121 and the second magnet slot 122, and the gap gradually increases in the radially outward direction; in the second magnet slot group 13, a gap is formed between the third magnet slot 131 and the fourth magnet slot 132, and the gap gradually increases in the radially outward direction. In the distribution of the two types of magnet slots, the spacing between the first magnet slot 121 and the second magnet slot 122 gradually increases in the radially outward direction. This can also be understood as the distance between the first magnet slot 121 and the second magnet slot 122 gradually increases in the direction away from the center of the rotor body 11. Similarly, the spacing between the third magnet slot 131 and the fourth magnet slot 132 gradually increases in the radially outward direction. This can also be understood as the distance between the third magnet slot 131 and the fourth magnet slot 132 gradually increases in the direction away from the center of the rotor body 11. The design of the inclined extension of the first magnet slot 121, the second magnet slot 122, the third magnet slot 131 and the fourth magnet slot 132 increases the length of the magnetic flux path compared to the existing scheme that extends directly in the radial direction, which can increase the magnetic flux and thus increase the output power of the motor 20.

[0073] According to one embodiment of the present invention, the rotor assembly 1 further includes a first magnet 1211, a second magnet 1221, a third magnet 1311, and a fourth magnet 1321. The first magnet 1211 and the second magnet 1221 are respectively housed in the first magnet slot 121 and the second magnet slot 122. In the cross-section of the rotor, the angle between the radial outer edge of the first magnet 1211 and the radial outer edge of the second magnet 1221 is α3, α3 = k3 * α1, and satisfies: 5 ≤ k3 ≤ 6. The third magnet 1311 and the fourth magnet 1321 are respectively housed in the third magnet slot 131 and the fourth magnet slot 132. In the cross-section of the rotor, the angle between the radial outer edge of the third magnet 1311 and the radial outer edge of the fourth magnet 1321 is α4, α4 = k4 * α2, and satisfies: 2 ≤ k4 ≤ 3.

[0074] Since fixing the values ​​of the first and second pole arc angles is equivalent to fixing the radial outer ends of the first magnet slot 121, the second magnet slot 122, the third magnet slot 131, and the fourth magnet slot 132, but the magnet angle between the first magnet 1211 and the second magnet 1221 and the magnet angle between the third magnet 1311 and the fourth magnet 1321 is not determined, it is necessary to rationally plan the magnet angle between the first magnet 1211 and the second magnet 1221 and the magnet angle between the third magnet 1311 and the fourth magnet 1321 to improve the performance of the motor 20.

[0075] Specifically, when the rotor is running at high speed, the centrifugal force on the area covered by the magnetic slot group in each magnetic pole of the rotor is proportional to its mass and the square of the radius of rotation. Within a certain range, the larger the magnetic angle of each magnetic slot group, the larger the span of the corresponding magnetic slot. At this time, the area covered by the magnetic slot group is larger, which leads to an increase in the stress on the area covered by the corresponding magnetic slot group. In order to prevent the rotor material from yielding at the limit speed, it is necessary to increase the thickness of the reinforcing structure on the rotor body 11. However, increasing the thickness of the reinforcing structure will lead to increased magnetic leakage. Therefore, it is necessary to rationally plan the magnetic angle of each magnetic slot group.

[0076] In any magnetic pole, such as Figure 3 As shown, in the first magnet slot group 12, the magnet angle formed between the radial outer edge of the first magnet 1211 and the radial outer edge of the second magnet 1221 is α3, and satisfies α3=k3*α1. Here, the radial outer edge can be simply understood as follows: both the first magnet 1211 and the second magnet 1221 are rectangular, and their edges closest to each other are the radial outer edges, where 5≤k3≤6. For example, when k1=0.33 and α1=19.8°, 99°≤α3≤118.8°, which can be understood as α3 being... The value is taken as k3 times α1. That is, in the first magnet slot group 12, the magnet angle between the first magnet 1211 and the second magnet 1221 can be determined according to the first pole arc angle. In this design scheme, if α3 is too large, that is, the magnet angle in the first magnet slot group 12 is too large, it will increase the area occupied by the first magnet slot group 12 in each magnetic pole, thereby increasing the centrifugal force on the corresponding magnet slot group covered area. If α3 is too small, it will limit the length of the magnetic flux path of the first magnet slot 121 and the second magnet slot 122, reduce the magnetic flux, and increase the magnetic field harmonics.

[0077] Similarly, in any magnetic pole, the magnetic angle formed between the radially outer edge of the third magnet 1311 and the radially outer edge of the fourth magnet 1321 in the second magnet slot group 13 is α4, and satisfies α4=k4*α1. Here, the radially outer edge can be simply understood as follows: both the third magnet 1311 and the fourth magnet 1321 are rectangles, and the edge closest to each other is the radially outer edge, where 2≤k4≤3. For example, when k2=0.59 and α2=35.4°, 70.8°≤α4≤106.2°, which can be understood as… α4 can be k4 times α2. That is, in the second magnetic steel groove group 13, the magnetic steel angle between the third magnet 1311 and the fourth magnet 1321 can be determined according to the second pole arc angle. In this design scheme, if α4 is too large, that is, the magnetic steel angle in the second magnetic steel groove group 13 is too large, it will increase the area occupied by the second magnetic steel groove group 13 in each magnetic pole, thereby increasing the centrifugal force on the corresponding magnetic steel groove group covered area. If α4 is too small, it will limit the length of the magnetic flux path of the first magnetic steel groove 121 and the second magnetic steel groove 122, reduce the magnetic flux, and increase the magnetic field harmonics.

[0078] In addition, such as Figure 9 As shown, Figure 9 The graph shows the relationship between torque ripple rate and k3 and k4. It is easy to see from the graph that when 5≤k3≤6 and 2≤k4≤3, the torque ripple rate is less than 2%. Therefore, the values ​​of α3 and α4 are within a suitable range under this condition, which helps to suppress the harmonic content of the magnetic field, improve the NVH performance of the motor, and thus reduce the vibration and noise of the motor.

[0079] In summary, the α3 and α4 design schemes allow for the rational planning of the first magnet slot group 12 and the second magnet slot group 13 in each magnetic pole, enabling more precise adjustment of the magnetic field distribution of the motor 20. This design helps reduce harmonics in the magnetic field, improves the sinusoidal nature of the magnetic field, and thus enhances the NVH performance of the motor 20. Simultaneously, the optimized magnetic field distribution also helps improve the torque density and efficiency of the motor 20, thereby improving its overall performance. Furthermore, this design considers the different characteristics of the first magnet slot group 12 and the second magnet slot group 13, setting different value ranges for k3 and k4 respectively. This differentiated design can better adapt to changes in the internal magnetic field of the motor 20, making the magnetic field more uniform and stable in the radial direction.

[0080] According to one embodiment of the present invention, k2 satisfies 0.58≤k2≤0.6; k1 satisfies 0.32≤k1≤0.34. Unlike the range of values ​​for k2 and k1 in the above embodiments, this embodiment further restricts the values ​​of k2 and k1, which can further optimize the efficiency, output power, and dynamic performance of the motor 20.

[0081] According to one embodiment of the present invention, a rotor auxiliary slot 15 is formed on the radially outer edge of the rotor body 11, opening radially outward. The rotor auxiliary slot 15 can effectively reduce magnetic field harmonics, which helps to improve the NVH performance of the motor 20. At the same time, the rotor auxiliary slot 15 can also increase the heat dissipation area, improve the heat dissipation efficiency of the motor 20, and ensure the stable operation of the motor 20 under harsh environments such as high load and high temperature.

[0082] According to one embodiment of the present invention, the central angle formed by the lines connecting the two ends of the rotor auxiliary slot 15 in the circumferential direction to the center of the rotor body 11 is β, and satisfies: 1°≤β≤2°. It can be observed that the range of β is small, meaning that the precision requirement of the rotor auxiliary slot 15 is high. By setting a high-precision rotor auxiliary slot 15, the performance of the motor 20 can be fine-tuned, further optimizing the electromagnetic performance of the motor 20, such as reducing electromagnetic noise and vibration, and improving the overall efficiency and performance of the motor 20. Furthermore, a small-sized rotor auxiliary slot 15 can ensure the structural strength of the rotor body 11, avoiding excessively large rotor auxiliary slots that reduce rotor strength and thus cause damage to the rotor during high-speed operation.

[0083] like Figure 10 As shown, Figure 10 The graph shows the relationship between torque ripple rate and β. It is easy to see from the graph that when 1°≤β≤2°, the torque ripple rate is less than 2%, which helps to suppress the harmonic content of the magnetic field, improve the NVH performance of the motor, and thus reduce the vibration and noise of the motor.

[0084] According to one embodiment of the present invention, the first magnet slot group 12 and the second magnet slot group 13 are symmetrically arranged about the d-axis. The angle between the straight line passing through the center of the rotor auxiliary slot 15 radially along the rotor body 11 and the d-axis is γ and satisfies: 0.7*α2≤γ≤0.75*α2.

[0085] Specifically, such as Figure 3 and Figure 4 As shown, where, Figure 4 The label 'd' in the diagram represents the d-axis. It's important to note that the d-axis is a virtual axis, and the straight line passing through the center of the rotor auxiliary slot 15 is also a virtual line. Figure 4The d-axis and the straight line passing through the center of the rotor auxiliary slot 15 are only for convenient labeling of γ and do not represent the actual structure. The first magnet slot group 12 and the second magnet slot group 13 are symmetrical about the d-axis, which improves the overall aesthetics of the rotor assembly 1 and makes the structure on the rotor assembly 1 uniformly distributed, avoiding excessively high or low local strength. The rotor auxiliary slot 15 is relatively small. Therefore, for any magnetic pole of the rotor, two symmetrical rotor auxiliary slots 15 can be set on both sides of the d-axis of the rotor body 11. The design of two rotor auxiliary slots 15 compared to one rotor auxiliary slot 15 can improve the heat dissipation effect of the rotor auxiliary slot 15 and further reduce magnetic field harmonics. At the same time, the symmetry of the two rotor auxiliary slots 15 about the d-axis ensures the balance and stability of the magnetic field of the motor 20. This symmetry helps to reduce the unbalanced components in the magnetic field, reduce the vibration and noise of the motor 20, and improve the smoothness of the motor 20's operation.

[0086] Secondly, such as Figure 4 As shown, by precisely controlling the angle γ between the center of the rotor auxiliary slot 15 and the d-axis, within the range of 0.7*α² to 0.75*α², a reasonable layout of the rotor auxiliary slot 15 is achieved. If γ is too large, i.e., the rotor auxiliary slot 15 is too far from the d-axis, the adjustment effect of the rotor auxiliary slot 15 on the magnetic field of the motor 20 will be weakened. If γ is too small, i.e., the rotor auxiliary slot 15 is too close to the d-axis, it will affect the setting of the magnetic isolation bridge at the radial outer ends of the first magnetic slot 121, the second magnetic slot 122, the third magnetic slot 131, and the fourth magnetic slot 132. Therefore, setting γ within the range of 0.7*α² to 0.75*α² can further optimize the electromagnetic performance of the motor 20, help adjust the air gap permeability, suppress specific harmonic components in the air gap magnetic flux density, thereby reducing the electromagnetic excitation force and reducing the torque pulsation and vibration of the motor 20.

[0087] In addition, such as Figure 11 As shown, Figure 11 The relationship between torque ripple rate and γ / α2 is shown in the figure. It is easy to see from the figure that when 0.7≤γ / α2≤0.75, the torque ripple rate is less than 1.5%, which helps to suppress the harmonic content of the magnetic field, improve the NVH performance of the motor, and thus reduce the vibration and noise of the motor.

[0088] According to one embodiment of the present invention, the radial depth of the rotor auxiliary groove 15 is L1 and satisfies: 0.3mm ≤ L1 ≤ 1mm. For example... Figure 4As shown, the radial depth of the rotor auxiliary slot 15 can be represented by L1. If the depth L1 of the rotor auxiliary slot 15 is greater than 1 mm, i.e., the rotor auxiliary slot 15 is too deep, it will reduce the structural strength of the rotor body 11. If the depth L1 of the rotor auxiliary slot 15 is less than 0.3 mm, i.e., the rotor auxiliary slot 15 is too shallow, it will affect the ability of the rotor auxiliary slot 15 to reduce magnetic field harmonics. Therefore, limiting the depth L1 of the rotor auxiliary slot 15 to the range of 0.3 mm to 1 mm will not significantly affect the structural strength of the rotor body 11, and can ensure the reliability and durability of the motor 20. In addition, the rotor auxiliary slot 15 within this range has low processing difficulty, which can optimize the electromagnetic performance of the motor 20 while ensuring manufacturing feasibility and economy.

[0089] According to one embodiment of the present invention, the rotor auxiliary slot 15 is constructed as an arc-shaped slot. Compared to rotor auxiliary slots 15 of other shapes, the arc-shaped slot can distribute the magnetic field more evenly, reduce harmonic components in the magnetic field, and thus reduce the electromagnetic noise and vibration of the motor 20. Simultaneously, the arc-shaped rotor auxiliary slot 15 can give the rotor body 11 better mechanical properties, enabling it to withstand higher stress and impact, which helps to enhance the structural strength of the motor 20 and improve its reliability and durability. Furthermore, the arc-shaped slot has a relatively simple shape and is easy to manufacture through processes such as machining or casting, reducing the manufacturing cost of the motor 20 and improving production efficiency.

[0090] According to one embodiment of the present invention, the second magnet slot group 13 further includes a fifth magnet slot 133 located between the third magnet slot 131 and the fourth magnet slot 132. There are multiple fifth magnet slots 133. The lengths of the third magnet 1311 in the third magnet slot 131 and the fourth magnet 1321 in the fourth magnet slot 132 in the extension direction of their respective corresponding magnet slots are L2. The length of the magnet in the fifth magnet slot 133 is L3, and satisfies: 1.9≤L2 / L3≤2.5.

[0091] Based on the preferred polar arc angle and magnet angle in the above embodiments, the relationship between the lengths of the third magnet 1311, the fourth magnet 1321, and the fifth magnet will affect the stress on the area covered by the corresponding magnet groove.

[0092] Specifically, a fifth magnet can be installed in the fifth magnet slot 133. The relationship between the lengths of the third magnet 1311, the fourth magnet 1321, and the fifth magnet can satisfy 1.9 ≤ L2 / L3 ≤ 2.5. When L2 / L3 > 2.5, L2 is too large and L3 is too small, which will increase the span between the reinforcing structure at one end of the third magnet slot 131 or the magnetic isolation bridge at the other end, thus increasing the stress in the area where the magnet slot group is located and affecting the safety of the rotor when rotating at high speed. When L2 / L3 < 1.9, L2 is too large and L3 is too small, which will lead to uneven distribution of mechanical strength of the rotor structure. Moreover, an excessively large L2 may cause local magnetic circuit saturation, making it impossible for magnetic flux to effectively pass through the magnets and air gap, thereby reducing the magnetic energy utilization rate of the motor 20.

[0093] The range of values ​​for L2 / L3 can also be referenced in Figure 7, showing the stress distribution of the reinforcing structure between the third magnet slot 131 or the fourth magnet slot 132 and the fifth magnet slot 133 when the rotor rotates at a speed of 30,000 rpm. Figure 7 As shown, it is not difficult to conclude Figure 7 As shown in the curves, when the sum of L1 and L2 remains constant and their ratio is between 1.9 and 2.5, the stress on the reinforcing structure between the third magnet slot 131 or the fourth magnet slot 132 and the fifth magnet slot 133 is relatively small. However, when the ratio is in other ranges, the stress on the reinforcing structure between the third magnet slot 131 or the fourth magnet slot 132 and the fifth magnet slot 133 easily exceeds the yield limit of the rotor material. Therefore, only when the sum of L1 and L2 remains constant and their ratio is between 1.9 and 2.5 can the thickness of the reinforcing structure between the third magnet slot 131 or the fourth magnet slot 132 and the fifth magnet slot 133 be appropriately reduced when the motor 20 reaches the same limiting speed. This ensures that the motor 20 can operate stably at ultra-high speeds while effectively reducing leakage flux and increasing the main magnetic flux content, thereby increasing the power density and torque density of the motor 20.

[0094] Therefore, setting L2 / L3 in the range of 1.9 to 2.5 helps to improve the output torque and power density of motor 20, meeting the performance requirements of various application scenarios.

[0095] In some embodiments, a sixth magnet slot may be provided between the first magnet slot 121 and the second magnet slot 122 in the first magnet slot group 12. The arrangement of magnets in the sixth magnet slot can refer to the above embodiments or be determined according to actual needs.

[0096] According to one embodiment of the present invention, a first connecting portion 141 is formed between two adjacent fifth magnet slots 133.

[0097] In actual processing, a first connecting part 141 can be provided between adjacent fifth magnet slots 133. The provision of the first connecting part 141 can increase the number of reinforcing structures on the rotor, which can improve the structural strength of the rotor body 11. When the motor 20 reaches the same speed, the thickness of the magnetic isolation bridge can be appropriately reduced to reduce magnetic leakage.

[0098] According to one embodiment of the present invention, a second connecting portion 142 is formed between the third magnet slot 131 and the fifth magnet slot 133, and a third connecting portion 143 is formed between the fourth magnet slot 132 and the fifth magnet slot 133. The third magnet slot 131, the fourth magnet slot 132, and the fifth magnet slot 133 cooperate to form a U-shaped structure. Compared with the "V"-shaped or "I"-shaped magnet slots in conventional technical solutions, the provision of the second connecting portion 142 and the third connecting portion 143 further increases the number of reinforcing structures on the rotor body 11, improves the overall strength of the rotor body 11, and allows the thickness of the magnetic isolation bridge to be thinner than in conventional solutions at the limit speed, thereby reducing magnetic leakage at the magnetic isolation bridge location, further reducing magnetic leakage of the motor 20 in the high-speed region, and improving the output power of the motor 20 in the high-speed region.

[0099] In some embodiments, a sixth magnetic groove is provided between the first magnetic groove 121 and the second magnetic groove 122. In this case, a fourth connecting part and a fifth connecting part may also be provided between the first magnetic groove 121 and the sixth magnetic groove, and between the second magnetic groove 122 and the sixth magnetic groove, respectively.

[0100] The motor 20 according to the present invention is briefly described below.

[0101] The motor 20 according to the present invention includes the rotor assembly 1 in the above embodiments. Since the motor 20 according to the present invention is provided with the rotor assembly 1 in the above embodiments, when the motor 20 is equipped with the rotor assembly 1 in the above embodiments, the output power of the motor 20 can be increased by increasing the magnetic flux and magnetic flux density, and the electromagnetic performance and NVH performance of the motor 20 can be optimized by reducing magnetic field harmonics, thereby improving the service life of the motor 20.

[0102] According to one embodiment of the present invention, the motor 20 further includes a stator 21, which is disposed on the outer periphery of the rotor assembly 1. An air gap 23 is formed between the stator 21 and the rotor body 11. The air gap 23 is d1 in the radial direction and satisfies: 1.5mm≤d1≤3mm.

[0103] According to the present invention, the motor 20 defines an air gap 23 between the stator 21 and the rotor body 11. The radial distance of the air gap 23 is d1, and satisfies: 1.5mm ≤ d1 ≤ 3mm. In the industry, the length of the air gap 23 in permanent magnet synchronous motors 20 is generally less than 1.5mm. Compared with the prior art's smaller air gap 23 width, the present invention increases the width of the air gap 23, which helps to suppress power attenuation and magnetic field harmonics in the high-speed region of the motor 20, and improves the efficiency and NVH performance of the motor 20.

[0104] Specifically, with the air gap magnetic flux density remaining constant, a larger air gap 23 length results in greater magnetic reluctance between the stator 21 and rotor body 11, leading to a smaller inductance in the motor 20. This increases the field weakening current in the high-speed constant-power region and also increases the output power in the high-speed region. Therefore, a larger air gap 23 design helps suppress power attenuation in the high-speed region. The constant air gap magnetic flux density here can be understood as increasing the amount of permanent magnets to ensure that the air gap 23's magnetic flux density is the same as in existing designs, thus avoiding the negative impacts of magnetic flux density variations.

[0105] like Figure 12 As shown, in order to keep the air gap magnetic flux density constant, the area ratio of the magnet in the rotor body 11 needs to increase with the increase of the width of the air gap 23. It can also be understood that when the width of the air gap 23 increases, in order to keep the magnetic flux density of the air gap magnetic field constant and the motor 20 maintains a high power density, the amount of magnets needs to be increased. When the width of the air gap 23 is greater than 3mm, the amount of magnets required is too large, which is not conducive to the lightweighting of the motor 20.

[0106] The width of the air gap 23 affects the power attenuation of the motor 20 in the high-speed range. Within a certain range, a larger air gap 23 results in less power attenuation; however, increasing the width of the air gap 23 affects the utilization rate of the permanent magnet. Therefore, the width of the air gap 23 needs to be maintained within a suitable range. Figure 18 As shown, the width of the air gap 23 and the power attenuation value are roughly linearly related within a certain range. When the width of the air gap 23 is less than 1.5 mm, the power attenuation is large. Increasing the width of the air gap 23 will increase the magnetic reluctance at the position of the air gap 23. When the width of the air gap 23 is greater than 3 mm, the magnetic reluctance is too large and the utilization rate of the permanent magnet is too low. Therefore, keeping the width of the air gap 23 between 1.5 mm and 3 mm can effectively suppress the power attenuation in the high-speed region while ensuring the utilization rate of the permanent magnet.

[0107] When motor 20 operates in the high-speed range, a large amount of eddy current loss is generated in the stator and rotor cores due to the magnetic field. Furthermore, the higher the rotational speed and frequency of motor 20, the higher the eddy current loss in rotor assembly 1. When the width of air gap 23 increases, the harmonic content in the magnetic field of air gap 23 decreases significantly, reducing eddy current loss in rotor assembly 1 at high speeds, thus improving the rated power and efficiency of motor 20 in the high-speed range. Therefore, increasing the width of air gap 23 can suppress magnetic field harmonics. When the width of air gap 23 is 1.5mm to 3mm, due to the large air gap 23 suppressing magnetic field harmonics, the torque fluctuation, torque amplitude at various orders, and radial electromagnetic force of motor 20 under maximum load are all at a relatively low level. At this point, even with direct pole configuration, motor 20 can still maintain good NVH performance. Compared to motor 20 using a skewed pole configuration to improve NVH performance, this not only improves the ease of manufacturing rotor assembly 1 but also reduces windage losses experienced by rotor assembly 1 during rotation, further improving the efficiency of motor 20.

[0108] According to one embodiment of the present invention, the stator 21 is provided with a plurality of stator slots 212 arranged at intervals in the circumferential direction, and flat wire windings 24 are provided in the stator slots 212.

[0109] Specifically, the stator 21 is provided with multiple stator slots 212 for assembling windings. The multiple stator slots 212 are spaced apart in the circumferential direction of the stator 21, and a flat wire winding 24 can be installed in each stator slot 212. Compared with traditional round wire windings, the gaps of the assembled flat wire windings 24 are smaller. Assembling flat wire windings 24 in the stator slots 212 can improve the slot fill factor of the stator slots 212, which can effectively improve the power density and efficiency of the motor 20.

[0110] According to one embodiment of the invention, the flat wire winding 24 in each of the stator slots 212 is configured to have at least 10 layers.

[0111] According to one embodiment of the present invention, the flat wire winding 24 in each stator slot 212 is constructed with at least 10 layers. Specifically, compared to the prior art scheme using 4 layers of flat wire winding 24, the present invention assembles at least 10 layers of flat wire winding 24 in each stator slot 212, increasing the number of layers of flat wire winding 24. This effectively reduces eddy current losses in the windings caused by the skin effect when the motor 20 operates in the high-speed range, thereby improving the efficiency and rated power of the motor 20 in the high-speed range. Combined with maintaining the air gap 23 width between 1.5mm and 3mm, the efficiency and rated power of the motor 20 in the high-speed range can be comprehensively improved to further meet the drive requirements.

[0112] Depend on Figure 13 and Figure 14It is easy to see that when the number of layers of flat wire winding 24 is increased, the eddy current loss of flat wire winding 24 decreases significantly and the efficiency is slightly improved. Therefore, under the same high-speed operating conditions, the motor 20 with 10 layers of flat wire winding 24 has lower losses than the motor 20 with 4 layers of flat wire winding in the prior art, and its rated power will also be higher under the same heat dissipation conditions.

[0113] According to one embodiment of the present invention, the inner circumference of the stator 21 is provided with a plurality of teeth 211 arranged at intervals in the circumferential direction, a stator groove 212 is formed between two adjacent teeth 211, and a stator auxiliary groove 213 that is recessed in the radial direction is provided on the tooth tip of at least one tooth 211 facing the air gap 23.

[0114] Specifically, the stator 21 is also provided with a plurality of teeth 211 arranged at intervals on its inner circumference. A stator slot 212 is formed between two adjacent teeth 211. The tooth tips of the teeth 211 protrude toward the stator slot 212 on both sides in the circumferential direction, which can improve the assembly stability of the flat wire winding 24. At least one of the teeth 211 has a stator auxiliary slot 213 that is recessed in the radial direction at the tooth tip position. The stator auxiliary slot 213 can effectively reduce the magnetic field harmonics of the air gap 23, thereby reducing the torque pulsation and electromagnetic radial force of the motor 20 and improving the NVH performance of the motor 20.

[0115] like Figure 15 As shown, Figure 15 The markings 426-435 on the left-hand coordinate axis can be interpreted as torque values. The dashed line represents the torque value over time when the stator 21 does not have the stator auxiliary slot 213, while the solid line represents the torque value over time after the stator 21 has the stator auxiliary slot 213. Figure 15 It is easy to see that when the stator auxiliary slot 213 is opened on the stator 21, the torque fluctuation is significantly reduced, that is, the torque pulsation is reduced, which is equivalent to effectively suppressing the tangential electromagnetic force, and can effectively improve the NVH performance of the motor 20.

[0116] like Figure 16 As shown, Figure 16 The text compares the radial pressure of the stator 21 with and without the stator auxiliary slot 213, representing two different conditions at different orders. Figure 16 It can be seen that when the stator auxiliary groove 213 is opened on the stator 21, the radial pressure of each order can be effectively reduced.

[0117] In some embodiments, the number of stator auxiliary slots 213 can be determined based on parameters such as the actual number of teeth 211 and the number of stator slots 212. For example, in a 6-stage, 72-slot stator 21, each stage has 12 stator slots 212 and 12 teeth 211. Since the motor 20 uses three-phase windings, each phase of the stator 21 has 4 stator slots 212 and 4 teeth 211. In this case, stator auxiliary slots 213 can be provided at the tooth tip positions of two of the teeth 211, i.e., two stator auxiliary slots 213 are machined. This can effectively reduce the harmonics of the magnetic field in the air gap 23 without affecting the structure and other performance characteristics of the motor 20. The arrangement of stator auxiliary slots 213 can be determined based on the actual number of teeth 211 in each stage.

[0118] According to one embodiment of the present invention, the width of the stator auxiliary groove 213 is d2, the tooth tip width of the tooth portion 211 is d3, and satisfies: 1 / 3≤d2 / d3≤1 / 2.

[0119] During the machining of the stator auxiliary slot 213, the relationship between the slot width d2 and the tooth tip width d3 of the tooth 211 needs to satisfy: 1 / 3 ≤ d2 / d3 ≤ 1 / 2. Here, the slot width can be understood as the width of the stator auxiliary slot 213. Specifically, the stator auxiliary slot 213 can effectively reduce magnetic field harmonics and improve the NVH performance of the motor 20. If d2 / d3 < 1 / 3, that is, the slot width of the stator auxiliary slot 213 is too small, the ability of the stator auxiliary slot 213 to reduce magnetic field harmonics will be weakened; if d2 / d3 > 1 / 2, that is, the slot width of the stator auxiliary slot 213 is too large, it will affect the mechanical structural strength of the stator 21. Therefore, d2 / d3 being in the range of 1 / 3 to 1 / 2 allows the stator 21 to effectively reduce magnetic field harmonics while ensuring the mechanical structural strength, thereby improving the efficiency and NVH performance of the motor 20.

[0120] like Figure 17 As shown, Figure 17 The dashed line represents the curve of torque ripple rate varying with different values ​​of d2 / d3, and the solid line represents the curve of average torque varying with different values ​​of d2 / d3. Figure 17 It is easy to see that when d2 / d3 is between 1 / 3 and 1 / 2, the torque fluctuation rate is lower without a significant decrease in average torque. Therefore, d2 / d3 in the range of 1 / 3 to 1 / 2 can improve the NVH performance of motor 20.

[0121] According to one embodiment of the present invention, the stator auxiliary groove 213 has a radial depth of d4, and satisfies: 0.1mm≤d4≤0.3mm.

[0122] During the machining of the stator auxiliary slot 213, the depth d4 of the stator auxiliary slot 213 must satisfy the following condition: 0.1mm ≤ d4 ≤ 0.3mm. This depth can be understood as the radial depth of the stator auxiliary slot 213. Specifically, a suitable depth of the stator auxiliary slot 213 helps improve the electromagnetic performance of the motor 20. When d4 < 0.1mm, meaning the depth of the stator auxiliary slot 213 is too shallow, it may not achieve the desired effect, resulting in a weakened ability of the stator auxiliary slot 213 to reduce magnetic field harmonics. Conversely, when d4 > 0.3mm, meaning the depth of the stator auxiliary slot 213 is too deep, it will affect the mechanical structural strength of the stator 21. A slot depth of 0.1mm to 0.3mm can effectively adjust the magnetic field distribution, improve the efficiency and power density of the motor 20, and while ensuring the structural strength of the stator 21, also reduce magnetic field harmonics, improving the NVH performance of the motor 20.

[0123] Furthermore, the arrangement of the stator auxiliary slot 213 is also related to the heat dissipation of the motor 20. When the stator auxiliary slot 213 satisfies 1 / 3 ≤ d2 / d3 ≤ 1 / 2 and 0.1mm ≤ d4 ≤ 0.3mm, it increases the heat dissipation area, improves the heat dissipation performance of the motor 20, helps reduce the heat generated by the motor 20 during operation, and improves the thermal stability of the motor 20. The depth range of 0.1mm to 0.3mm makes the machining process of the stator auxiliary slot 213 relatively easy to control, and also helps to ensure machining accuracy and consistency.

[0124] According to one embodiment of the present invention, N magnetic poles are formed on the rotor body 11 at circumferential intervals, satisfying: 2≤N≤8, where N is an even number; the stator 21 is provided with N*M stator slots 212, satisfying: M=3x, where x is a positive integer. The rotor body 11 of the present invention is provided with N magnetic poles, where N can be any one of 2, 4, 6, or 8. Correspondingly, the number of stator slots 212 is N*M, i.e., 2M, 4M, 6M, or 8M. Since the motor 20 uses three-phase windings, M is a multiple of 3, i.e., M=3x, where x is a positive integer. It can also be understood that the arrangement schemes on the rotor body 11 and stator 21 of the present invention, such as the width of the air gap 13 and the number of layers of the flat wire winding 14, can be used for motors 20 of different specifications, thus having a wide range of applications.

[0125] In some embodiments, the rotor body 11 may also be provided with multiple sets of weight-reducing holes 223. Each set of weight-reducing holes 223 may contain one or more holes. The weight-reducing holes 223 may be arranged radially outward from the corresponding magnet slot group in each magnetic pole. The arrangement of the weight-reducing holes 223 enables stress dispersion in the rotor assembly 1 during high-speed rotation, preventing stress concentration and damage at localized locations on the rotor body 11, thus improving the service life and safety of the rotor assembly 1. The multiple weight-reducing holes 223 may correspond one-to-one with multiple magnetic poles, or multiple weight-reducing holes 223 may correspond to one magnetic pole, such as... Figure 2 As shown, the specific values ​​can be determined based on the actual stress distribution.

[0126] The vehicle 30 according to the present invention is briefly described below.

[0127] The vehicle 30 according to the present invention includes the motor 20 in the above embodiments. Since the vehicle 30 according to the present invention is equipped with the motor 20 in the above embodiments, when the vehicle 30 is equipped with the motor 20, the power performance and NVH performance of the vehicle 30 can be effectively improved. The motor 20 has high reliability and service life, which can improve the safety of the vehicle 30. At the same time, it can reduce the cost of replacing and repairing the motor 20 of the vehicle 30 and improve the user experience of the vehicle 30.

[0128] 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" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.

[0129] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0130] In the description of this invention, "a plurality of" means two or more.

[0131] In the description of this invention, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0132] In the description of this invention, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0133] 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.

[0134] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A rotor assembly for an electric motor, characterized in that, include: The rotor body (11) is provided with p magnetic pole pairs, and a first magnetic slot group (12) and a second magnetic slot group (13) are formed on the rotor body (11) in a radial direction. The first magnet slot group (12) includes a first magnet slot (121) and a second magnet slot (122). In the first magnet slot group, the minimum central angle formed between the radial outer end of the first magnet slot (121) and the radial outer end of the second magnet slot (122) and the center of the rotor body (11) is α1, α1 = (k1 * 180°) / p; the second magnet slot group (13) includes a third magnet slot (131) and a fourth magnet slot (132). In the second magnet slot group, the minimum central angle formed between the radial outer end of the third magnet slot (131) and the radial outer end of the fourth magnet slot (132) and the center of the rotor body (11) is α2, α2 = (k2 * 180°) / p; and satisfies: 0.3≤k1≤0.35, 0.55≤k2≤0.

65.

2. The rotor assembly (1) for an electric motor according to claim 1, characterized in that, In the first magnet slot group (12), a gap is formed between the first magnet slot (121) and the second magnet slot (122), and the gap gradually increases in the radially outward direction; In the second magnetic steel groove group (13), a gap is formed between the third magnetic steel groove (131) and the fourth magnetic steel groove (132), and the gap gradually increases in the radially outward direction.

3. The rotor assembly (1) for an electric motor according to claim 1, characterized in that, Also includes: A first magnet (1211) and a second magnet (1221), wherein the first magnet (1211) and the second magnet (1221) are respectively housed in a groove higher than the first magnet groove (121) and the second magnet groove (122); On the cross-section of the rotor, the angle between the radial outer edge of the first magnet (1211) and the radial outer edge of the second magnet (1221) is α3, α3=k3*α1, and satisfies: 5≤k3≤6; The third magnet (1311) and the fourth magnet (1321) are respectively housed in the third magnet groove (131) and the fourth magnet groove (132); On the cross-section of the rotor, the angle between the radial outer edge of the third magnet (1311) and the radial outer edge of the fourth magnet (1321) is α4, α4=k4*α2, and satisfies: 2≤k4≤3.

4. The rotor assembly (1) for an electric motor according to claim 2, characterized in that, The condition k2 satisfies 0.58≤k2≤0.6; the condition k1 satisfies 0.32≤k1≤0.

34.

5. The rotor assembly (1) for an electric motor according to claim 1, characterized in that, The outer radial edge of the rotor body (11) is formed with a rotor auxiliary groove that opens outward in the radial direction.

6. The rotor assembly (1) for an electric motor according to claim 5, characterized in that, The central angle formed by the two ends of the rotor auxiliary groove in the circumferential direction with the center of the rotor body (11) is β, and satisfies: 1°≤β≤2°.

7. The rotor assembly (1) for an electric motor according to claim 5, characterized in that, The first magnet slot group (12) and the second magnet slot group (13) are respectively symmetrically arranged about the d-axis. The angle between the straight line passing through the center of the rotor auxiliary slot (15) radially along the rotor body (11) and the d-axis is γ and satisfies: 0.7*α2≤γ≤0.75*α2.

8. The rotor assembly (1) for an electric motor according to claim 5, characterized in that, The radial depth of the rotor auxiliary groove is L1 and satisfies: 0.3mm≤L1≤1mm.

9. The rotor assembly (1) for an electric motor according to any one of claims 5-8, characterized in that, The rotor auxiliary slot is constructed as a circular arc slot.

10. The rotor assembly (1) for an electric motor according to claim 1, characterized in that, The second magnetic steel groove group (13) also includes a fifth magnetic steel groove (133) located between the third magnetic steel groove (131) and the fourth magnetic steel groove (132), and there are multiple fifth magnetic steel grooves (133); The length of the magnet in the third magnet groove (131) in the extension direction of the third magnet groove (131) and the length of the magnet in the fourth magnet groove (132) in the extension direction of the fourth magnet groove (132) are both L2, and the length of the magnet in the fifth magnet groove (133) is L3, satisfying: 1.9≤L2 / L3≤2.

5.

11. The rotor assembly (1) for an electric motor according to claim 10, characterized in that, A first connecting portion (141) is formed between two adjacent fifth magnet slots (133).

12. The rotor assembly (1) for an electric motor according to claim 11, characterized in that, The rotor body (11) has a second connecting portion (142) formed between the third magnet slot (131) and the fifth magnet slot (133), and a third connecting portion (143) formed between the fourth magnet slot (132) and the fifth magnet slot (133).

13. An electric motor (20), characterized in that, include: The rotor assembly (1) according to any one of claims 1-12.

14. The motor (20) according to claim 13, characterized in that, Also includes: The stator (21) is disposed on the outer periphery of the rotor assembly (1). An air gap (23) is formed between the stator (21) and the rotor body (11). The air gap (23) is d1 in the radial direction and satisfies: 1.5mm≤d1≤3mm.

15. The motor (20) according to claim 14, characterized in that, The stator (21) is provided with a plurality of stator slots (212) arranged at intervals in the circumferential direction, and flat wire windings (24) are provided in the stator slots (212).

16. The motor (20) according to claim 15, characterized in that, The flat wire windings (24) in each of the stator slots (212) are constructed to have at least 10 layers.

17. The motor (20) according to claim 14, characterized in that, The stator (21) has a plurality of teeth (211) arranged at intervals in the circumferential direction on its inner periphery. A stator groove (212) is formed between two adjacent teeth (211). At least one tooth (211) has a stator auxiliary groove (213) that is recessed in the radial direction on the tooth tip facing the air gap (23).

18. The motor (20) according to claim 17, characterized in that, The width of the stator auxiliary groove (213) is d2, and the tooth tip width of the tooth (211) is d3, and satisfies: 1 / 3≤d2 / d3≤1 / 2.

19. The motor (20) according to claim 17, characterized in that, The stator auxiliary groove (213) has a radial depth of d4, and satisfies: 0.1mm≤d4≤0.3mm.

20. The motor (20) according to claim 17, characterized in that, The rotor body (11) has N magnetic poles arranged circumferentially, and satisfies: 2≤N≤8, where N is an even number; the stator (21) has N*M stator slots, and satisfies: M=3x, where x is a positive integer.

21. A vehicle (30), characterized in that, Includes the motor (20) as described in any one of claims 13-20.

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