Rotor assembly for an electric machine, electric machine and vehicle

Abstract

This invention discloses a rotor assembly for an electric motor, an electric motor, and a vehicle. The rotor assembly includes a rotor body, a first permanent magnet, and a second permanent magnet. The rotor body has multiple magnetic barrier slots arranged at intervals radially away from the center of the rotor body. The first permanent magnet and the second permanent magnet are respectively disposed within two of the magnetic barrier slots, with the first permanent magnet located radially inside the second permanent magnet. The coercivity of the first permanent magnet is greater than that of the second permanent magnet. According to this invention, the rotor assembly, by providing magnetic barrier slots, increases the saliency ratio of the motor, improves the reluctance torque ratio of the motor, reduces the amount of permanent magnets used, reduces cost, and minimizes the risk of demagnetization of the first and second permanent magnets.

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] Electric vehicles typically use either asynchronous motors or permanent magnet synchronous motors for their drive motors. While asynchronous motors are cheaper, they are less efficient and have a smaller high-speed constant power range. Permanent magnet synchronous motors, on the other hand, are more efficient, have a larger high-speed constant power range, and are more expensive.

[0003] CN112928842B discloses a rotor lamination, including a lamination body. The lamination body has a central hole and multiple circumferentially evenly arranged permanent magnet pole slots on the outside of the central hole. Each permanent magnet pole slot includes two first permanent magnet slots and one second permanent magnet slot. The two first permanent magnet slots are arranged in a figure-eight shape with their large openings facing outwards. The second permanent magnet slot is located at the large opening of the figure-eight shape. Each first permanent magnet slot contains a first permanent magnet, and each second permanent magnet slot contains a second permanent magnet. The outer surface of the second permanent magnet is a first arc surface, and the second permanent magnet slot has a corresponding arc surface adapted to the first arc surface. By increasing the magnetic flux area of ​​the entire permanent magnet, the rotor lamination reduces the magnetic flux path from the second permanent magnet to the outer circle of the rotor, thereby reducing magnetic resistance and increasing output torque.

[0004] In related technologies, vehicle drive motors use a large number of rare-earth permanent magnets to generate electromagnetic torque, which is costly, and the permanent magnets in the motor are at risk of demagnetization. Summary of the Invention

[0005] 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 setting magnetic barrier slots, increases the saliency ratio of the motor, improves the reluctance torque ratio of the motor, reduces the amount of permanent magnets used, reduces cost, and minimizes the risk of demagnetization of the first and second permanent magnets.

[0006] The present invention also provides an electric motor having the above-described rotor assembly.

[0007] The present invention also provides a vehicle having the above-described motor.

[0008] The rotor assembly according to the present invention is used in a vehicle. The rotor assembly includes: a rotor body having a plurality of magnetic barrier slots arranged at intervals in a radial direction away from the center of the rotor body; a first permanent magnet and a second permanent magnet, the first permanent magnet and the second permanent magnet being respectively disposed in two of the magnetic barrier slots, and the first permanent magnet being located radially inside the second permanent magnet; wherein the coercivity of the first permanent magnet is greater than the coercivity of the second permanent magnet.

[0009] The rotor assembly according to the present invention increases the saliency ratio of the motor and improves the reluctance torque by providing multiple magnetic barrier slots on the rotor body, with these slots spaced radially away from the rotor body center. Simultaneously, by placing a first permanent magnet and a second permanent magnet in two magnetic barrier slots respectively, the first and second permanent magnets provide direct-axis permanent magnet flux to the motor, increasing the torque density and improving the permanent magnet torque. By increasing the proportion of reluctance torque, the amount of permanent magnets used is reduced, thus lowering costs. Furthermore, by placing the first permanent magnet with higher coercivity in the magnetic barrier slot closer to the rotor body center and the second permanent magnet with lower coercivity in the magnetic barrier slot farther from the rotor body center, the risk of permanent magnet demagnetization can be reduced while lowering costs.

[0010] According to some embodiments of the present invention, the magnetic barrier groove is constructed as three, namely a first magnetic barrier groove, a second magnetic barrier groove and a third magnetic barrier groove arranged sequentially in a radial direction away from the center, wherein the first permanent magnet is disposed in the first magnetic barrier groove and the second permanent magnet is disposed in the second magnetic barrier groove.

[0011] According to some embodiments of the present invention, the first magnetic barrier groove includes: a first transverse groove, the extension direction of the first transverse groove being perpendicular to the radial direction; a first inclined groove, the first inclined groove being constructed as two and respectively disposed at both ends of the first transverse groove, the two first inclined grooves extending radially outward in a direction away from each other; and a first permanent magnet being disposed in the first transverse groove and / or the first inclined groove respectively; the second magnetic barrier groove includes: a second transverse groove, the extension direction of the second transverse groove being perpendicular to the radial direction; a second inclined groove, the second inclined groove being constructed as two and respectively disposed at both ends of the second transverse groove, the two second inclined grooves extending radially outward in a direction away from each other; and a second permanent magnet being disposed in the second transverse groove and / or the second inclined groove respectively.

[0012] According to some embodiments of the present invention, the third magnetic barrier groove includes: a third inclined groove, wherein the third inclined groove is constructed as two and disposed on both sides of the symmetrical center of the second transverse groove.

[0013] According to some embodiments of the present invention, the included angle between the two first inclined grooves is α1, the included angle between the two second inclined grooves is α2, and the included angle between the two third inclined grooves is α3, satisfying: 90°<α1=α2=α3≤94°.

[0014] According to some embodiments of the present invention, the magnetic barrier grooves are constructed as multiple sets spaced apart along the circumference of the rotor body.

[0015] According to some embodiments of the present invention, a first magnetic shielding element is provided at the radial outer end of the first inclined groove, a second magnetic shielding element is provided at the radial outer end of the second inclined groove, and a third magnetic shielding element is provided at the radial outer end of the third inclined groove.

[0016] According to some embodiments of the present invention, an auxiliary groove is formed on the outer periphery of the rotor body, and the auxiliary groove is configured to be a plurality of grooves evenly arranged along the circumference of the rotor body.

[0017] The motor according to the present invention is briefly described below.

[0018] The motor according to the present invention includes the rotor assembly described in any of the above embodiments. Since the motor according to the present invention includes the rotor assembly described in any of the above embodiments, the motor according to the present invention, while capable of outputting torque equal to that of a permanent magnet motor, uses a small amount of permanent magnets, resulting in low cost. Furthermore, the permanent magnets are not easily demagnetized and have good durability.

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

[0020] The vehicle according to the present invention includes the motor described in any of the above embodiments. Because the vehicle according to the present invention includes the motor described in any of the above embodiments, the vehicle according to the present invention has low cost and low failure rate due to the low cost and high durability of the motor.

[0021] 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

[0022] 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:

[0023] Figure 1 This is a schematic diagram of the rotor assembly according to the present invention;

[0024] Figure 2 yes Figure 1 A magnified view of a portion of the image.

[0025] Figure label:

[0026] Rotor assembly 1;

[0027] Rotor body 11;

[0028] Magnetic barrier groove 12;

[0029] First magnetic barrier groove 121, first permanent magnet 1211, first transverse groove 1212, first inclined groove 1213;

[0030] Second magnetic barrier groove 122, second permanent magnet 1221, second transverse groove 1222, second inclined groove 1223;

[0031] Third magnetic barrier groove 123, third inclined groove 1231;

[0032] Auxiliary slot 13. Detailed Implementation

[0033] 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.

[0034] The following is for reference. Figures 1-2 The rotor assembly 1 according to an embodiment of the present invention is described.

[0035] The rotor assembly 1 according to the invention is used in vehicles, such as... Figure 1 As shown, the rotor assembly 1 includes a rotor body 11, a first permanent magnet 1211, and a second permanent magnet 1221. The rotor body 11 is provided with a plurality of magnetic barrier slots 12, which are arranged at intervals in a radial direction away from the center of the rotor body 11. The first permanent magnet 1211 and the second permanent magnet 1221 are respectively disposed in two magnetic barrier slots 12, and the first permanent magnet 1211 is located radially inside the second permanent magnet 1221. The coercivity of the first permanent magnet 1211 is greater than that of the second permanent magnet 1221.

[0036] In related technologies, traditional permanent magnet motors use a large number of rare-earth permanent magnets, and the motor's output torque is only the torque generated by the excitation flux linkage of the permanent magnets, resulting in high costs. To reduce the amount of rare-earth permanent magnets used in motors, the applicant's research has found that the saliency ratio of the motor can be changed to generate reluctance torque, thereby increasing the proportion of reluctance torque in the motor's output torque, reducing the amount of permanent magnets used, and lowering the motor's cost. In related technologies, ferrite permanent magnets, although cheaper than rare-earth permanent magnets, have poor magnetic properties. The applicant's research has found that when using only ferrite permanent magnets for excitation, the motor's torque density does not meet the requirements of vehicle drive motors. To improve the motor's torque density, a portion of permanent magnets with better magnetic properties can be used in the motor.

[0037] In related technologies, motors are prone to demagnetization due to the magnetic properties of permanent magnets. The applicant's research has found that when using multiple permanent magnets in a motor, placing the permanent magnet with higher coercivity closer to the rotor center can improve the overall demagnetization resistance of the motor.

[0038] Therefore, the rotor assembly 1 of this application is used in a motor. By providing multiple magnetic barrier slots 12 on the rotor body 11 of the rotor assembly 1, and arranging the multiple magnetic barrier slots 12 at intervals in the radial direction away from the center of the rotor body 11, the salient pole ratio of the motor is increased, and the reluctance torque of the motor is improved. At the same time, by providing a first permanent magnet 1211 and a second permanent magnet 1221 in the two magnetic barrier slots 12 respectively, the first permanent magnet 1211 and the second permanent magnet 1221 provide direct-axis permanent magnet flux to the motor, thereby increasing the torque density of the motor and improving the permanent magnet torque of the motor.

[0039] Under the premise of meeting the output torque requirements of the vehicle's drive motor, since the output torque of the motor with the rotor assembly 1 of this application is equal to the reluctance torque plus the permanent magnet torque, the rotor assembly 1 of this application increases the proportion of reluctance torque and reduces the proportion of permanent magnet torque by setting the magnetic barrier slot 12, thereby reducing the amount of permanent magnets used and reducing costs.

[0040] Furthermore, since permanent magnets closer to the center of the rotor body 11 are more prone to demagnetization, permanent magnets with high coercivity have strong resistance to demagnetization but are expensive. Therefore, the rotor assembly 1 of this application can reduce the risk of permanent magnet demagnetization while reducing costs by placing the first permanent magnet 1211 with higher coercivity in the magnetic barrier slot 12 close to the center of the rotor body 11 and placing the second permanent magnet 1221 with lower coercivity in the magnetic barrier slot 12 far from the center of the rotor body 11.

[0041] The first permanent magnet can be a neodymium iron boron (NdFeB) permanent magnet, and the second permanent magnet can be a ferrite permanent magnet. NdFeB permanent magnets have greater coercivity than ferrite permanent magnets. Because NdFeB permanent magnets are closer to the center than ferrite permanent magnets, and permanent magnets closer to the center are more prone to demagnetization, NdFeB permanent magnets have strong demagnetization resistance, thus reducing the risk of motor demagnetization. Meanwhile, ferrite permanent magnets have a high risk of demagnetization at low temperatures, while NdFeB permanent magnets have a high risk of demagnetization at high temperatures. Since the temperature coefficients of ferrite and NdFeB permanent magnets are opposite, this can improve the motor's anti-demagnetization performance under different temperature conditions, reducing the risk of demagnetization.

[0042] Therefore, the rotor assembly 1 of this application increases the salient pole ratio of the motor by setting the magnetic barrier slot 12, increases the proportion of magnetic reluctance torque of the motor, reduces the amount of permanent magnets used, reduces costs, and has a low risk of demagnetization of the first permanent magnet 1211 and the second permanent magnet 1221.

[0043] According to some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the magnetic barrier slots 12 are constructed as three, namely a first magnetic barrier slot 121, a second magnetic barrier slot 122, and a third magnetic barrier slot 123, arranged sequentially in a radial direction away from the center. A first permanent magnet 1211 is disposed in the first magnetic barrier slot 121, and a second permanent magnet 1221 is disposed in the second magnetic barrier slot 122. The first permanent magnet 1211 and the second permanent magnet 1221 are respectively disposed in the first magnetic barrier slot 121 and the second magnetic barrier slot 122, which are relatively close to the center of the rotor body 11. This improves the utilization rate of the permanent magnets, thereby increasing the permanent magnet torque of the motor. Since the first magnetic barrier slot 121 is relatively close to the center of the rotor body 11, the risk of permanent magnet demagnetization can be reduced by placing the first permanent magnet 1211 in the first magnetic barrier slot 121.

[0044] In related technologies, when the number of magnetic barrier slots in the rotor assembly is less than three layers, the motor has a low saliency ratio and low reluctance torque. To meet the output torque requirements of the vehicle's drive motor, a large number of permanent magnets are needed, resulting in high costs. When the number of magnetic barrier slots in the rotor assembly is greater than three layers, the manufacturing process of the rotor assembly becomes more difficult, the magnetic circuit saturation intensifies, the utilization rate of permanent magnets decreases, and the improvement in motor output torque is limited. In the embodiments of this application, the magnetic barrier slot 12 is constructed with three layers, namely the first magnetic barrier slot 121, the second magnetic barrier slot 122, and the third magnetic barrier slot 123. The reluctance torque is high, the manufacturing process of the rotor assembly 1 is less difficult, and the utilization rate of permanent magnets is high.

[0045] Permanent magnets can be installed in the third magnetic barrier slot 123 to increase permanent magnet torque, or permanent magnets can be omitted to increase the salient pole ratio of the motor and increase the proportion of reluctance torque of the motor.

[0046] According to some embodiments of the present invention, the first magnetic barrier groove 121 includes a first transverse groove 1212 and a first inclined groove 1213, wherein the extension direction of the first transverse groove 1212 is perpendicular to the radial direction; the first inclined groove 1213 is configured as two and is respectively disposed at both ends of the first transverse groove 1212, and the two first inclined grooves 1213 extend radially outward in a direction away from each other; the first permanent magnet 1211 is respectively disposed in the first transverse groove 1212 and / or the first inclined groove 1213; the second magnetic barrier groove 122 includes a second transverse groove 1222 and a second inclined groove 1223, wherein the extension direction of the second transverse groove 1222 is perpendicular to the radial direction; the second inclined groove 1223 is configured as two and is respectively disposed at both ends of the second transverse groove 1222, and the two second inclined grooves 1223 extend radially outward in a direction away from each other; the second permanent magnet 1221 is respectively disposed in the second transverse groove 1222 and / or the second inclined groove 1223.

[0047] In related technologies, the shape of the magnetic barrier groove affects the magnetic flux density distribution of the rotor assembly.

[0048] In the embodiments of this application, the magnetic field density generated by the first permanent magnet 1211 in the first horizontal groove 1212 and the first inclined groove 1213 of the first magnetic barrier groove 121 is uniform, which improves the uniformity of magnetic flux density distribution, thereby reducing torque pulsation, reducing noise, and improving efficiency. The arrangement of the second magnetic barrier groove 122 is similar and will not be described further here.

[0049] According to some embodiments of the present invention, such as Figure 2 As shown, the third magnetic barrier groove 123 includes a third inclined groove 1231, which is constructed as two grooves and disposed on both sides of the symmetrical center of the second transverse groove 1222. When no permanent magnet is disposed in the third magnetic barrier groove 123, the construction of two third inclined grooves 1231 disposed on both sides of the symmetrical center of the second transverse groove 1222 can reduce the pulsation of reluctance torque, thereby reducing the torque pulsation of the motor and reducing noise. When a permanent magnet is disposed in the third magnetic barrier groove 123, the magnetic field generated by the permanent magnet in the third magnetic barrier groove 123 can also be made uniform, reducing the pulsation of permanent magnet torque. According to some embodiments of the present invention, the included angle between the two first inclined grooves 1213 is α1, the included angle between the two second inclined grooves 1223 is α2, and the included angle between the two third inclined grooves 1231 is α3, satisfying: 90°<α1=α2=α3≤94°.

[0050] In related technologies, the magnitudes of α1, α2, and α3 are related to the saturation of magnetic flux density. If α1, α2, and α3 are too small or too large, it will lead to uneven magnetic flux density. If the magnetic flux density is too high, it will cause electromagnetic vibration, large torque pulsation, increased electromagnetic noise of the motor, and reduced motor efficiency. If the magnetic flux density is too low, it will limit the torque of the motor.

[0051] In the embodiments of this application, 90°<α1=α2=α3≤94°, the uniformity of magnetic flux density is high, the torque pulsation is small, the electromagnetic noise of the motor is low, and the motor efficiency is high.

[0052] According to some embodiments of the present invention, the magnetic barrier slots 12 are configured as multiple sets spaced upwards along the circumference of the rotor body 11. The multiple sets of magnetic barrier slots 12 can improve torque, and the multiple sets of magnetic barrier slots 12 spaced upwards along the circumference of the rotor body 11 can improve the magnetic field stability of the rotor assembly 1 during rotation and reduce torque pulsation.

[0053] According to some embodiments of the present invention, a first magnetic shielding element is provided at the radially outer end of the first inclined slot 1213, a second magnetic shielding element is provided at the radially outer end of the second inclined slot 1223, and a third magnetic shielding element is provided at the radially outer end of the third inclined slot 1231. The first, second, and third magnetic shielding elements can reduce the leakage magnetic coefficient of the permanent magnets in the rotor assembly 1, improve the utilization rate of the permanent magnets, thereby reducing the amount of permanent magnets used and reducing costs. At the same time, the first, second, and third magnetic shielding elements can increase the structural strength of the rotor assembly 1, enabling the rotor assembly 1 to better meet the speed requirements.

[0054] In some embodiments, the thickness of the first magnetic shielding component is greater than the thickness of the second magnetic shielding component, and the thickness of the second magnetic shielding component is greater than the thickness of the third magnetic shielding component, thereby further improving the strength of the rotor assembly 1 and enabling the rotor assembly 1 to operate under high-speed conditions.

[0055] In related technologies, the first, second, and third magnetic shielding components have limited effect on improving the structural strength of the rotor assembly, and the rotor assembly may not meet the structural strength requirements.

[0056] In the embodiments of this application, a first reinforcing rib is provided between the first transverse groove 1212 and the first inclined groove 1213, and a second reinforcing rib is provided between the second transverse groove 1222 and the second inclined groove 1223. The first and second reinforcing ribs can improve the structural strength of the rotor assembly 1, enabling the rotor assembly 1 to operate at higher speeds and improving the torque output capability of the motor. In particular, the width of the first reinforcing rib is greater than the width of the second reinforcing rib, which can further improve the structural strength of the rotor assembly 1.

[0057] According to some embodiments of the present invention, such as Figure 2 As shown, auxiliary grooves 13 are formed on the outer periphery of the rotor body 11. These auxiliary grooves 13 are configured as multiple grooves evenly arranged circumferentially along the rotor body 11. The auxiliary grooves 13 can alter the equivalent air gap length of the rotor assembly 1, reducing torque pulsation, lowering electromagnetic force density, and reducing noise. Furthermore, by configuring the auxiliary grooves 13 as multiple grooves evenly arranged circumferentially along the rotor body 11, the effectiveness and stability of the auxiliary grooves 13 can be improved.

[0058] The effect of the auxiliary groove 13 in reducing torque ripple and electromagnetic force density is related to the depth and shape of the auxiliary groove 13. Therefore, the effect of the auxiliary groove 13 in reducing electromagnetic force density and reducing torque ripple can be improved by optimizing the depth and shape of the auxiliary groove 13.

[0059] In some embodiments, the first permanent magnet 1211 is constructed as a neodymium iron boron (NdFeB) permanent magnet, and the thickness of the NdFeB permanent magnet is greater than or equal to four times the air gap length; the second permanent magnet 1221 is constructed as a ferrite permanent magnet, and the thickness of the ferrite permanent magnet is greater than or equal to six times the air gap length. NdFeB permanent magnets are prone to demagnetization at high operating temperatures, and a thickness greater than or equal to four times the air gap length can reduce the risk of demagnetization at high temperatures. Ferrite permanent magnets are prone to demagnetization at low operating temperatures, and a thickness greater than or equal to six times the air gap length can reduce the risk of demagnetization at low temperatures.

[0060] The motor according to the present invention is briefly described below.

[0061] The motor according to the present invention includes the rotor assembly 1 in any of the above embodiments. Since the motor according to the present invention includes the rotor assembly 1 in any of the above embodiments, the motor according to the present invention can output the same torque as a permanent magnet motor, while using less permanent magnet, resulting in lower cost, and the permanent magnet is not easily demagnetized and has good durability.

[0062] The vehicle according to the present invention is briefly described below.

[0063] The vehicle according to the present invention includes the motor in any of the above embodiments. Since the vehicle according to the present invention includes the motor in any of the above embodiments, the vehicle according to the present invention has low cost and low failure rate because the motor has low cost and good durability.

[0064] 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.

[0065] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0066] In the description of this invention, "a plurality of" means two or more.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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 for an electric motor, characterized in that, include: The rotor body has a plurality of magnetic barrier slots arranged at intervals in a radial direction away from the center of the rotor body. A first permanent magnet and a second permanent magnet are respectively disposed in the two magnetic barrier slots, and the first permanent magnet is located radially inside the second permanent magnet; wherein the coercivity of the first permanent magnet is greater than that of the second permanent magnet. The magnetic barrier groove is constructed as three, namely a first magnetic barrier groove, a second magnetic barrier groove, and a third magnetic barrier groove arranged sequentially in a radial direction away from the center. The first magnetic barrier groove includes: a first transverse groove, the extension direction of which is perpendicular to the radial direction; and a first inclined groove, which is constructed as two and respectively disposed at both ends of the first transverse groove. The second magnetic barrier groove includes: a second transverse groove, the extension direction of which is perpendicular to the radial direction; and a second inclined groove, which is constructed as two grooves and is respectively disposed at both ends of the second transverse groove. The third magnetic barrier groove includes: a third inclined groove, wherein the third inclined groove is constructed as two and is disposed on both sides of the symmetrical center of the second transverse groove; The included angle between the two first inclined grooves is α1, the included angle between the two second inclined grooves is α2, and the included angle between the two third inclined grooves is α3, satisfying: 90°<α1=α2=α3≤94°.

2. A rotor assembly for an electric motor according to claim 1, characterized in that, The first permanent magnet is disposed in the first magnetic barrier groove, and the second permanent magnet is disposed in the second magnetic barrier groove.

3. A rotor assembly for an electric motor according to claim 2, characterized in that, The two first inclined slots extend radially outward in a direction away from each other; The first permanent magnets are respectively disposed in the first transverse groove and / or the first inclined groove; The second magnetic barrier slot includes: The two second inclined slots extend radially outward in a direction away from each other; The second permanent magnet is respectively disposed in the second horizontal groove and / or the second inclined groove.

4. A rotor assembly for an electric motor according to any one of claims 1-3, characterized in that, The magnetic barrier grooves are constructed in multiple sets spaced apart along the circumference of the rotor body.

5. A rotor assembly for an electric motor according to claim 3, characterized in that, The first inclined groove is provided with a first magnetic shielding element at its radial outer end, the second inclined groove is provided with a second magnetic shielding element at its radial outer end, and the third inclined groove is provided with a third magnetic shielding element at its radial outer end.

6. A rotor assembly for an electric motor according to claim 1, characterized in that, An auxiliary groove is formed on the outer periphery of the rotor body, and the auxiliary groove is constructed to be a plurality of grooves evenly arranged along the circumference of the rotor body.

7. An electric motor comprising the rotor assembly as described in any one of claims 1-6.

8. A vehicle comprising the motor of claim 7.

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