Rotor assembly and motor

Abstract

The utility model discloses a rotor assembly and a motor, and relates to the technical field of motors, the rotor assembly comprises a rotor iron core, the rotor iron core is provided with 2P magnetic steel grooves, 4P magnetic isolation grooves and 2P grooves, each groove extends along the axial direction of the rotor iron core, penetrates through two end surfaces of the rotor iron core, and corresponds to an area between two adjacent magnetic steel grooves, the 4P magnetic isolation grooves are distributed at intervals in the circumferential direction of the rotor core, one magnetic isolation groove is formed in one side, close to the outer periphery of the rotor core, of each first groove section, and through the combined action of the magnetic isolation grooves and the grooves, (2P-Z and 2f) and (4P-Z and 4f) (P is the number of rotor pole pairs, and Z is the number of stator grooves) order electromagnetic excitation force is weakened, meanwhile, armature reaction and magnetic leakage suppression are achieved, and no-load back electromotive force is enhanced. And the current required by unit torque is reduced, so that the energy efficiency is improved, and the low-noise and low-cost design of the product is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, and particularly relates to a rotor assembly and a motor. Background Art

[0002] At present, rare earth permanent magnet motors have the advantages of simple and reliable structure, high efficiency and large power density, and are widely used. With the improvement of users' requirements for motor quality (high cost performance, low noise), designing rare earth permanent magnet motors with low noise, high efficiency and low cost is one of the core pursuits in the current product design and manufacturing. Summary of the Utility Model

[0003] The main purpose of the utility model is to propose a rotor assembly and a motor, aiming to provide a rotor assembly that realizes armature reaction, suppresses leakage magnetic flux, and improves the energy efficiency of the motor.

[0004] To achieve the above object, the rotor assembly proposed by the utility model includes:

[0005] A rotor core, on which 2P magnetic steel slots are provided and extend along its axial direction and penetrate through its two end faces, the plurality of magnetic steel slots are arranged at intervals along the circumferential direction of the rotor core, each magnetic steel slot has two first slot segments extending along the radial direction of the rotor core, and the two first slot segments are arranged away from each other in the direction away from the middle of the rotor core;

[0006] Wherein, a plurality of grooves are recessed on the outer peripheral edge of the rotor core, each groove extends along the axial direction of the rotor core and penetrates through its two end faces, and corresponds to the area between two adjacent magnetic steel slots;

[0007] The rotor core is further provided with 4P magnetic isolation slots that extend along the axial direction of the rotor core and penetrate through its two end faces, the 4P magnetic isolation slots are arranged at intervals along the circumferential direction of the rotor core, and one magnetic isolation slot is arranged on one side of each first slot segment close to the outer peripheral edge of the rotor core.

[0008] In an embodiment, the distance between the side wall of the magnetic isolation slot close to the outer peripheral side of the rotor core and the outer peripheral surface of the rotor core in the radial direction of the rotor core is d1, and 0.4 mm ≤ d1 ≤ 0.9 mm; and / or,

[0009] The minimum gap between the magnetic isolation slot and the first slot segment is d2, and 0.4 mm ≤ d2 ≤ 0.6 mm. In an embodiment, the central angle of the rotor core corresponding to the magnetic isolation slot is Rfimbs1, and 25° ≤ Rfimbs1 ≤ 35°; and / or,

[0010] The central angle Rfimbs2 corresponding to the two magnetic isolation grooves inside the magnetic steel groove with respect to the rotor core is such that 13° ≤ Rfimbs2 ≤ 23°.

[0011] In one embodiment, each of the first groove segments has an inner end close to the other first groove segment and an outer end far from the other first groove segment;

[0012] The magnetic isolation groove has a first end and a second end distributed circumferentially on the rotor core. The first end of the magnetic isolation groove is arranged close to the outer end of the first groove segment, and the second end of the magnetic isolation groove is arranged close to the inner end of the first groove segment;

[0013] The magnetic isolation groove has a first side wall and a second side wall connected between the first end and the second end. The first side wall is arranged close to the corresponding first groove segment, the second side wall is arranged close to the outer periphery of the rotor core. The first side wall includes a first side wall segment, the second side wall includes a second side wall segment, and the first side wall segment and the second side wall segment are arranged to gradually open from the first end to the second end of the magnetic isolation groove;

[0014] The first side wall and the second side wall of the magnetic isolation groove have the largest opening angle at the first side wall segment and the second side wall segment;

[0015] The included angle between the extending direction of the first side wall segment and the extending direction of the corresponding first groove segment is Angle1, and the included angle between the extending direction of the second side wall segment and the extending direction of the first groove segment is Angle2, where 44° ≤ Angle1 ≤ 54° and 71° ≤ Angle2 ≤ 81°.

[0016] In one embodiment, the groove is arranged to gradually expand in the outward direction; and / or,

[0017] The groove extends to the area between two adjacent magnetic steel grooves.

[0018] In one embodiment, each of the first groove segments has an inner end close to the other groove segment and an outer end far from the other first groove segment;

[0019] The rotor assembly further includes a pair of magnetic steels correspondingly arranged in the magnetic steel grooves corresponding to the two first groove segments. There is an installation gap between the magnetic steel and the outer end of the corresponding first groove segment, and an inner magnetic bridge is defined between the installation gap and the outer periphery of the rotor core.

[0020] In one embodiment, the inner magnetic bridge includes a first magnetic bridge segment and a second magnetic bridge segment connected in sequence;

[0021] The installation gap and the corresponding groove define the first magnetic bridge segment;

[0022] A second magnetic bridge segment is defined between the installation gap and the outer peripheral wall of the rotor core;

[0023] The width OBW of the first magnetic bridge segment is set to be equivalent to that of the second magnetic bridge segment.

[0024] In one embodiment, a pair of permanent magnets is arranged in each of the permanent magnet slots, and the central angle corresponding to each pair of permanent magnets with respect to the rotor core is Rfip, where 130° ≤ Rfip ≤ 139°; and / or,

[0025] The included angle formed between the two first slot segments is AngleV, where 110° ≤ AngleV ≤ 155°.

[0026] In one embodiment, a plurality of groups of inclined slots are recessed in the outer peripheral edge of the rotor core. The plurality of groups of inclined slots are distributed at intervals along the circumferential direction of the rotor core, and a groove is arranged between two adjacent groups of inclined slots. Each inclined slot extends along the axial direction of the rotor core and penetrates through its two end faces.

[0027] In one embodiment, a pair of permanent magnets is arranged in each of the permanent magnet slots, and the central angle corresponding to each pair of permanent magnets with respect to the rotor core is Rfip;

[0028] The inclined slot has a third side wall close to the corresponding groove, and P times the central angle of the third side wall corresponding to the rotor core is NAngleq;

[0029] P times the included angle formed by the connection lines of the bottoms of the two inclined slots in each group of inclined slots and the center of the rotor core is NAngleV;

[0030] Wherein, |Rfip - NAngleV - NAngleq| ≤ 5°.

[0031] In one embodiment, 2 ≤ P ≤ 5.

[0032] The present utility model further provides a motor, the motor includes a rotor assembly, and the rotor assembly includes:

[0033] A rotor core, on which 2P permanent magnet slots are arranged along its axial direction and penetrate through its two end faces. The plurality of permanent magnet slots are arranged at intervals along the circumferential direction of the rotor core. Each permanent magnet slot has two first slot segments extending along the radial direction of the rotor core, and the two first slot segments are arranged to be away from each other in the direction away from the middle of the rotor core;

[0034] Among them, a plurality of grooves are recessed in the outer peripheral edge of the rotor core, and each of the grooves extends along the axial direction of the rotor core and penetrates through its two end faces, and corresponds to the region between two adjacent magnet slots;

[0035] 4P magnetic isolation grooves are further provided on the rotor core, which extend along the axial direction of the rotor core and penetrate through its two end faces. The 4P magnetic isolation grooves are arranged at intervals along the circumferential direction of the rotor core, and one magnetic isolation groove is arranged on one side of each first groove section close to the outer peripheral edge of the rotor core.

[0036] In the technical solution of the present invention, one magnetic isolation groove is arranged on one side of each first groove section close to the outer peripheral edge of the rotor core, which can optimize the magnetic field distribution, reduce the cogging effect, reduce the electromagnetic noise, improve the dynamic characteristics, etc., effectively suppress the generation of harmonics. Compared with arranging two adjacent magnetic isolation grooves at this place, it is more manufacturing-friendly. The groove is arranged in the region between two adjacent magnet slots. The structure formed by the groove around the rotor can provide a more favorable path, so that more magnetic flux passes through the rotor core instead of leaking to the air or other parts, thereby reducing the magnetic leakage loss, making the air-gap magnetic flux between the rotor and the stator more concentrated, thereby increasing the effective magnetic flux. By the combined action of the magnetic isolation groove and the groove, the electromagnetic excitation forces of the (2P-Z, 2f) and (4P-Z, 4f) (P is the number of rotor pole pairs, Z is the number of stator slots) orders are weakened, while realizing armature reaction and magnetic leakage suppression, enhancing the no-load back electromotive force, reducing the current required for unit torque, and further improving the energy efficiency, realizing low-noise and low-cost design of the product. Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0038] Figure 1 It is a schematic structural diagram of a rotor assembly in the related art;

[0039] Figure 2 It is a schematic structural diagram of the first embodiment of the rotor assembly provided by the present invention;

[0040] Figure 3 For Figure 1 the schematic diagram of the design parameters of the rotor assembly in

[0041] Figure 4 It is a schematic structural diagram of the second embodiment of the rotor assembly provided by the present invention;

[0042] Figure 5 Schematic diagram of the structure of the third embodiment of the rotor assembly provided by the present utility model.

[0043] Explanation of the reference numerals in the drawings:

[0044] 10’, rotor core; a’, magnet slot; c’, magnetic isolation slot; a1’, first slot section;

[0045] 10, rotor core; a, magnet slot; a1, first slot section; b, groove; c, magnetic isolation slot; 101, first side wall section; 102, second side wall section; 103, inner magnetic bridge; 1031, first magnetic bridge section; 1032, second magnetic bridge section; d, inclined slot; 104, third side wall; 20, magnet;

[0046] 1, Rfip; 2, AngleV; 3, d1; 4, Rfimbs1; 5, Rfimbs2; 6, d2; 7, Angle1; 8, Angle2; 9, NAngle; 10, NAngled; 11, NAngleq; 12, OBW.

[0047] The realization, functional features and advantages of the purpose of the present utility model will be further described in conjunction with the embodiments with reference to the accompanying drawings. Detailed implementation manners

[0048] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0049] It should be noted that if there are directional indications (such as up, down, left, right, front, back,...) involved in the embodiments of the present utility model, the directional indications are only used to explain the relative position relationship and movement conditions between the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0050] In addition, if there are descriptions such as "first", "second", etc. in the embodiments of the present utility model, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel scenarios. Taking "A and / or B" as an example, it includes scenario A, or scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0051] The present utility model provides a rotor assembly to provide a rotor assembly that can achieve armature reaction, suppress leakage magnetic flux, and improve the energy efficiency of the motor.

[0052] Please refer to Figures 2 to 5 , in an embodiment of the present utility model, the rotor assembly includes a rotor core 10, and 2P magnetic steel slots a are provided on the rotor core 10 and extend along its axial direction and penetrate through its two end faces. The plurality of magnetic steel slots a are arranged at intervals along the circumferential direction of the rotor core 10. Each of the magnetic steel slots a has two first slot segments a1 extending along the radial direction of the rotor core 10, and the two first slot segments a1 are arranged to be away from each other in the direction away from the middle of the rotor core 10. Wherein, a plurality of grooves b are recessed on the outer peripheral edge of the rotor core 10, and each of the grooves b extends along the axial direction of the rotor core 10 and penetrates through its two end faces, and corresponds to the area between two adjacent magnetic steel slots a; 4P magnetic isolation slots c are further provided on the rotor core 10 and extend along the axial direction of the rotor core 10 and penetrate through its two end faces. The 4P magnetic isolation slots c are arranged at intervals along the circumferential direction of the rotor core 10, and one magnetic isolation slot c is provided on one side of each first slot segment a1 close to the outer peripheral edge of the rotor core 10.

[0053] It should be noted that the two first slot segments a1 can be connected or not connected. When the two first slot segments a1 are connected, the noise level of the motor can be improved to some extent, but correspondingly, the efficiency of the motor will be reduced; when the two first slot segments a1 are not connected, the noise of the motor is relatively large, but the efficiency of the motor will be improved compared with the case where the two first slot segments a1 are connected. Therefore, whether the two first slot segments a1 are connected or not needs to be adjusted accordingly in combination with the application scenario (the speed of the motor) and the industry.

[0054] It should be noted that during the operation of the rotor, due to the non-linear relationship between the magnetic field intensity and the magnetic flux, or the fact that the tooth slots between the rotor and the stator can cause periodic changes in the magnetic field, harmonics will be generated during the operation of the motor, affecting the efficiency, performance, and lifespan of the motor.

[0055] On one side of each of the first slot segments a1 close to the outer peripheral edge of the rotor core 10, there is provided a magnetic isolation slot c, such that the magnetic flux is restricted at the edge of the rotor, changing the magnetic field distribution within the rotor, reducing the generation of high-frequency harmonics. Certain high-frequency harmonic components (such as even harmonics) will be effectively suppressed because the change in magnetic flux at the edge of the rotor core 10 is more intense. The presence of the magnetic isolation slot c can effectively reduce the influence of these frequency components. By providing the magnetic isolation slot c at the edge of the rotor, the change in magnetic flux can be smoothed, reducing the influence of the tooth slot effect, thereby reducing the generation of harmonics. At the same time, providing the magnetic isolation slot c can reduce the electromagnetic noise generated during the operation of the motor. Since electromagnetic noise is usually closely related to harmonics, reducing the noise will also reduce the generation of harmonics.

[0056] In the related art, please refer to Figure 1 , when 2P magnetic steel slots a' are arranged at intervals along the circumferential direction on the rotor core 10', each magnetic steel slot a' includes two first slot segments a1' extending radially along the rotor core 10. On one side of each first slot segment a1' close to the outer peripheral edge of the rotor core 10', there are provided two adjacent magnetic isolation slots c' for suppressing the generation of harmonics. However, the stamping of the slit magnetic isolation slot c' requires the mold to have a slender boss, so there is a problem of easy fatigue.

[0057] In this embodiment, on one side of each of the first slot segments a1 close to the outer peripheral edge of the rotor core 10, there is provided a magnetic isolation slot c, without requiring the mold to have a slender boss. The magnetic isolation slot c has a large area, and the corresponding force-bearing surface of the mold boss is large, so the mold is not easily fatigued.

[0058] By recessing a plurality of grooves b on the outer peripheral edge of the rotor core 10, the grooves b can change the flow path of the magnetic flux, making the air-gap magnetic flux between the rotor and the stator more concentrated, thereby increasing the effective magnetic flux. Through the design of the grooves b, the generation of leakage magnetic flux can be reduced, ensuring that more magnetic flux passes through the air gap, thereby improving the overall magnetic flux utilization rate. And the increase in the effective magnetic flux enhances the generation of the induced electromotive force in the stator coil and strengthens the no-load back electromotive force. During no-load operation, the back electromotive force is generated by the magnetic flux cut in the stator winding. By optimizing the magnetic flux path, the grooves b can increase the magnitude of the back electromotive force, thereby improving the performance of the motor under no-load conditions.

[0059] It should also be noted that the no-load back EMF refers to the electromotive force induced in the stator winding when a motor or generator and other electrical equipment are operating without a load (i.e., no external load is connected). Specifically, it is the induced electromotive force generated by the rotor cutting the magnetic flux lines during rotation. The no-load back EMF is one of the important indicators for evaluating the performance of an electric machine. It reflects the flux and speed characteristics of the electric machine under no-load conditions. A higher no-load back EMF means that the electric machine can utilize electrical energy more effectively during rotation, thereby improving efficiency.

[0060] In the technical solution of the present utility model, a magnetic isolation slot c is provided on one side of each of the first slot sections a1 close to the outer peripheral edge of the rotor core 10, which can optimize the magnetic field distribution, reduce the cogging effect, lower the electromagnetic noise, improve the dynamic characteristics, etc., effectively suppress the generation of harmonics. Compared with setting two adjacent magnetic isolation slots c at this position, it is more manufacturing-friendly. A groove b is provided in the region corresponding to the area between two adjacent magnetic steel slots a. The structure formed by the groove b around the rotor can provide a more favorable path, enabling more magnetic flux to pass through the rotor core 10 rather than leaking into the air or other parts, thereby reducing the magnetic leakage loss, making the air-gap magnetic flux between the rotor and the stator more concentrated, and thus increasing the effective magnetic flux. By the combined action of setting the magnetic isolation slot c and the groove b, the electromagnetic excitation forces of the (2P-Z, 2f) and (4P-Z, 4f) (P is the number of rotor pole pairs, Z is the number of stator slots) orders are weakened, while the armature reaction and magnetic leakage suppression are realized, the no-load back EMF is enhanced, the current required per unit torque is reduced, and thus the energy efficiency is improved, achieving a low-noise and low-cost design of the product.

[0061] In this embodiment, please refer to Figure 3 , the distance between the side wall of the magnetic isolation slot c close to the outer peripheral side of the rotor core 10 and the outer peripheral surface of the rotor core 10 in the radial direction of the rotor core 10 is d1, and 0.4 mm ≤ d1 ≤ 0.9 mm; and / or, the minimum gap between the magnetic isolation slot c and the first slot section a1 is d2, and 0.4 mm ≤ d2 ≤ 0.6 mm.

[0062] Among them, d1 can be set to 0.5 mm, 0.6 mm, 0.7 mm or 0.8 mm, etc., and d2 can be 0.45 mm, 0.50 mm, 0.55 mm or 0.6 mm, etc. Specifically, it can be designed according to the actual situation, and the embodiments of this specification do not limit this.

[0063] When the distance between the magnetic isolation groove c and the outer peripheral surface of the rotor core 10 is too large, it may cause the distribution of magnetic flux in the air gap to become uneven, thereby reducing the magnetic flux density in the air gap, affecting the output power and efficiency of the motor. It will lead to more leakage magnetic flux, causing energy loss and reducing the overall performance of the motor. The reduction of the effective magnetic flux means that the torque generated by the motor will decrease, affecting its load capacity and starting performance. At the same time, it will cause an increase in harmonic interference of the motor, thus affecting the operating characteristics of the motor. If the distance between the magnetic isolation groove c and the outer peripheral surface of the rotor core 10 is too small, it will cause the rotor core 10 to be magnetically saturated under high load, affecting the magnetic circuit performance and efficiency of the motor.

[0064] Setting the distance between the magnetic isolation groove c and the magnetic steel groove a, and the distance between the magnetic isolation groove c and the outer peripheral surface of the rotor core 10 within the above reasonable range can ensure the effective transfer of magnetic flux in the air gap, as well as between the magnetic isolation groove c and the rotor core 10, enhance the magnetic flux density, thereby improving the output power and efficiency of the motor. It can reduce the generation of leakage magnetic flux, reduce energy loss, and improve the overall performance and efficiency of the motor. And it can reduce the air gap non-uniformity, reduce the vibration and noise during the operation of the motor, and improve the user experience.

[0065] Please refer to Figure 3 , in this embodiment, the central angle of the rotor core 10 corresponding to the magnetic isolation groove c is Rfimbs1, 25° ≤ Rfimbs1 ≤ 35°; and / or, the central angles of the two magnetic isolation grooves c located inside the magnetic steel groove a corresponding to the rotor core 10 are Rfimbs2, 13° ≤ Rfimbs2 ≤ 23°.

[0066] Among them, Rfimbs1 can be set to 25°, 27°, 29°, 31°, 33° or 35°, etc., and Rfimbs2 can be set to 13°, 15°, 17°, 19°, 21° or 23°, etc. Specifically, it can be designed according to the actual situation, and the embodiments of this specification do not limit this.

[0067] It should be noted that for the performance of the motor, because a larger magnetic isolation groove c can more effectively change the magnetic flux path, optimize the magnetic flux distribution, reduce magnetic leakage, thereby improving the efficiency and output torque of the motor. At the same time, it can reduce the leakage of magnetic flux through non-expected paths, thereby increasing the magnetic flux density and magnetic flux, and increasing the output torque, efficiency and torque density of the motor. While a smaller magnetic isolation groove c may not be able to effectively change the magnetic flux path, resulting in magnetic flux leakage and reducing the magnetic flux density, thereby causing a decrease in the efficiency and torque of the motor.

[0068] Regarding the noise aspect, when the magnetic isolation groove c is relatively small, the magnetic isolation groove c may not be able to effectively reduce the harmonic magnetic field, and it may also cause the iron core to be more likely to saturate, thereby generating more harmonic magnetic fields, resulting in an increase in the vibration and noise of the motor.

[0069] In order to optimize the performance requirements and noise control of the motor, it is optimal to set the range of the central angle of the rotor core 10 corresponding to the magnetic isolation groove c within the range of 25° to 35°.

[0070] It should also be noted that the spacing of the magnetic isolation grooves c affects the uniformity of the rotor magnetic field. If the spacing is too large, it may lead to uneven magnetic field distribution, thereby affecting the efficiency and output torque of the motor. A more uniform magnetic field can improve the performance of the motor. And the design of the spacing also affects the formation of eddy currents. A smaller spacing may lead to an increase in eddy current losses, thereby reducing the overall efficiency of the motor. At the same time, the spacing of the magnetic isolation grooves c directly affects the noise and vibration characteristics during the operation of the motor. A larger spacing may cause resonance of the iron core or unstable magnetic pulling force, resulting in an increase in noise.

[0071] Since a reasonable spacing design helps to reduce eddy current losses and improve the efficiency of the motor. By optimizing the spacing and setting the central angle of the two magnetic isolation grooves c located inside the magnetic steel groove a corresponding to the rotor core 10 between 13° and 23°, the noise and vibration during the operation of the motor can be reduced.

[0072] Specifically, please refer to Figure 3, in this embodiment, each of the first slot segments a1 has an inner end close to the other first slot segment a1 and an outer end far from the other first slot segment a1; the magnetic isolation slot c has a first end and a second end distributed in the circumferential direction of the rotor core 10. The first end of the magnetic isolation slot c is arranged close to the outer end of the first slot segment a1, and the second end of the magnetic isolation slot c is arranged close to the inner end of the first slot segment a1; the magnetic isolation slot c has a first side wall and a second side wall connected between the first end and the second end. The first side wall is arranged close to the corresponding first slot segment a1, and the second side wall is arranged close to the outer peripheral edge of the rotor core 10. The first side wall includes a first side wall segment 101, and the second side wall includes a second side wall segment 102. The first side wall segment 101 and the second side wall segment 102 are arranged to gradually open from the first end to the second end of the magnetic isolation slot c; the first side wall and the second side wall of the magnetic isolation slot c have the largest opening angle at the first side wall segment 101 and the second side wall segment 102; the included angle between the extending direction of the first side wall segment 101 and the extending direction of the corresponding first slot segment a1 is Angle1, and the included angle between the extending direction of the second side wall segment 102 and the extending direction of the first slot segment a1 is Angle2, 44° ≤ Angle1 ≤ 54°, and 71° ≤ Angle2 ≤ 81°.

[0073] Among them, Angle1 can be set to 44°, 46°, 48°, 50°, 52° or 54°, etc., and Angle2 can be set to 71°, 73°, 75°, 77°, 79° or 81°, etc. Specifically, it can be designed according to the actual situation, and the embodiments of this specification do not limit this.

[0074] Because the size of the included angle will affect the concentration degree and distribution uniformity of the magnetic flux. When the included angle is too small, it may cause uneven concentration of the magnetic flux, forming local saturation, and then affecting the output performance of the motor. Whether the included angle is too large or too small may cause an increase in eddy current loss, thereby affecting the efficiency and heating of the motor. It will also affect the magnetic field strength and direction in the air gap, thereby affecting the interaction between the rotor and the stator and the starting and running performance of the motor. A larger included angle may cause the change of the magnetic force lines to be uneven, thus increasing the noise. And designing the included angles of Angle1 and Angle2 within the above reasonable range can reduce the vibration during operation and reduce the noise.

[0075] It should be noted that, please refer to Figures 2 to 4 , in some embodiments, the magnetic isolation slot c is arranged in a shape similar to a triangle, and an acute angle of the triangle faces the corresponding groove b. The extending directions of the two sides of the acute angle and the corresponding first slot segment a1 are set within the above-mentioned included angle range, that is, the motor performance can be improved while reducing the noise.

[0076] Please refer to Figure 5 , in some other embodiments, the magnetic isolation groove c is arranged in a rhomboid-like shape, and an acute angle of the rhomboid faces the corresponding groove b. The extension directions of the two sides of the acute angle with respect to the corresponding first groove segment a1 are set within the above-mentioned included angle range, that is, while improving the motor performance, the noise can be reduced.

[0077] By setting the magnetic isolation groove c to have a triangular-like or quadrilateral-like feature, a similar purpose can be achieved while the manufacturability is also better.

[0078] The shape of the magnetic isolation groove c is not limited to the above-mentioned triangular-like or rhomboid-like shapes, and it can also be pentagon-like or other irregular shapes, as long as an acute angle is set to face the corresponding groove b, and the extension directions of the two sides of the acute angle with respect to the corresponding first groove segment a1 are set within the above-mentioned included angle range.

[0079] It should be noted that since the shape and position of the groove b will affect the magnetic flux distribution, stress concentration, and mechanical properties of the material, sharp edges may be more likely to generate cracks under cyclic loads. To avoid stress concentration at the groove corners of the groove b and reduce the overall mechanical strength of the rotor, please refer to Figures 2 to 4 , in one embodiment, the groove b is arranged to gradually expand in the outward direction. It can be understood that the groove b is set as a V-shaped groove, and the V-shaped groove may help to enhance the no-load back electromotive force and improve the motor performance.

[0080] Please refer to Figure 5 , in another embodiment, the groove b extends to the area between two adjacent magnetic steel grooves a. Since the edges of the square groove are relatively smooth and the stress distribution is relatively uniform, it can effectively reduce stress concentration, the stress distribution is better, and the smooth square groove provides better fatigue tolerance.

[0081] The shape of the groove b is set according to the application scenario and design requirements, and a trade-off needs to be made between the motor performance and the mechanical strength. The V-shaped groove performs well in stress distribution and is suitable for applications requiring high reliability.

[0082] Furthermore, please refer to Figure 2 and Figure 3 , in this embodiment, each first groove segment a1 has an inner end close to another groove segment and an outer end far from another first groove segment a1; the rotor assembly further includes a pair of magnetic steels 20 corresponding to the two first groove segments a1 in each magnetic steel groove a, and an installation gap is reserved between the magnetic steel 20 and the outer end of the corresponding first groove segment a1, and an inner magnetic bridge 103 is defined between the installation gap and the outer peripheral edge of the rotor core 10.

[0083] It should be noted that setting the gap can facilitate the installation of the permanent magnet 20 and also improve the performance of the motor, such as reducing eddy current loss.

[0084] Specifically, the inner magnetic bridge 103 can change the path of magnetic flux from the permanent magnet 20 to the stator core. By setting a gap between the permanent magnet 20 and the rotor core 10, the magnetic flux path becomes longer, and the magnetic resistance on the path also changes, which helps to smooth the change of magnetic flux density, thereby improving the sinusoidality of the back electromotive force.

[0085] When the motor rotates, the magnetic flux will induce a voltage in the stator winding. If the magnetic flux density distribution is uneven, harmonic components will appear in the back electromotive force waveform. By setting the inner magnetic bridge 103, the distribution of the magnetic flux density can be made more uniform, thereby improving the sinusoidality of the back electromotive force.

[0086] By setting a gap between the permanent magnet 20 and the rotor core 10, the length of the eddy current path can also be increased, dispersing the eddy currents, thereby reducing the intensity of individual eddy currents. The reduction of the eddy current intensity means the reduction of eddy current loss.

[0087] At the gap between the permanent magnet 20 and the rotor core 10, the magnetic flux density is relatively low, so less eddy current is generated in this area. By adjusting the distance between the permanent magnet 20 and the rotor core 10, the magnetic flux density can be further controlled, thereby reducing the generation of eddy currents.

[0088] Furthermore, please refer to Figure 3 , in this embodiment, the inner magnetic bridge 103 includes a first magnetic bridge segment 1031 and a second magnetic bridge segment 1032 connected in sequence; the first magnetic bridge segment 1031 is defined between the installation gap and the corresponding groove b; the second magnetic bridge segment 1032 is defined between the installation gap and the outer peripheral wall of the rotor core 10; the widths OBW of the first magnetic bridge segment 1031 and the second magnetic bridge segment 1032 are set to be equivalent.

[0089] It should be noted that "the inner magnetic bridge 103 includes a first magnetic bridge segment 1031 and a second magnetic bridge segment 1032 connected in sequence": This indicates that the inner magnetic bridge 103 consists of two parts, that is, the first magnetic bridge segment 1031 and the second magnetic bridge segment 1032 are continuously connected.

[0090] "The first magnetic bridge segment 1031 is defined between the installation gap and the corresponding groove b": The first magnetic bridge segment 1031 is mainly responsible for connecting the magnetic flux path between the permanent magnet 20 and the groove b.

[0091] "The installation gap defines the second magnetic bridge segment 1032 between the outer peripheral wall of the rotor core 10": The second magnetic bridge segment 1032 is mainly responsible for connecting the magnetic flux path between the permanent magnet 20 and the outer surface of the rotor core 10.

[0092] "The widths of the first magnetic bridge segment 1031 and the second magnetic bridge segment 1032 are set to be equivalent": This means that the first magnetic bridge segment 1031 and the second magnetic bridge segment 1032 are designed to have similar widths. Such a setting ensures that the magnetic flux can maintain a relatively uniform distribution when passing through these two magnetic bridge parts, as well as the continuity of the magnetic flux path, so as to reduce magnetic leakage, improve the utilization rate of permanent magnets, optimize the performance of the motor, and improve the sinusoidality of the back electromotive force. Because the optimization of the magnetic flux path can reduce the influence of the cogging effect, and at the same time, it also helps to reduce eddy current losses, because the uniform distribution of the magnetic flux density can reduce the generation of eddy currents.

[0093] Specifically, please refer to Figure 3 , in this embodiment, a pair of permanent magnets 20 are arranged in each magnetic steel groove a, and the central angle corresponding to each pair of permanent magnets 20 with respect to the center of the rotor core 10 is Rfip, 130° ≤ Rfip ≤ 139°; and / or, the included angle formed between the two first groove segments a1 is AngleV, 110° ≤ AngleV ≤ 155°.

[0094] The central angle corresponding to each pair of permanent magnets 20 with respect to the center of the rotor core 10 is Rfip. It should be noted that the "central angle" here refers to the angle formed between the center point of the rotor core 10 and this pair of permanent magnets 20. This angle is an important parameter in the design, which affects the magnetic field distribution and the performance of the motor.

[0095] Setting the range of the central angle Rfip corresponding to each pair of permanent magnets 20 with respect to the center of the rotor core 10 to be greater than or equal to 130° and less than or equal to 139° indicates that the central angle occupied by each pair of permanent magnets 20 must be between 130° and 139°. Such a setting is used to optimize the magnetic field distribution, thereby improving the efficiency and stability of the motor.

[0096] Rfip can be set to 130°, 132°, 134°, 136°, 138° or 139° etc. Specifically, it can be designed according to the actual situation, and the embodiments of this specification do not limit this.

[0097] The range of the included angle AngleV formed between the two first groove segments a1 is set to be greater than or equal to 110° and less than or equal to 155° to optimize the magnetic flux, reduce noise or improve mechanical strength.

[0098] AngleV can be set to 110°, 115°, 120°, 125°, 130°, 135°, 140°, 145°, 150° or 155°, etc. Specifically, it can be designed according to the actual situation, and the embodiments of this specification do not limit this.

[0099] Further, please refer to Figure 2 , Figure 3 and Figure 5 , in this embodiment, a plurality of sets of inclined slots d are recessed on the outer peripheral edge of the rotor core 10. The plurality of sets of inclined slots d are distributed at intervals along the circumferential direction of the rotor core 10, and a groove b is provided between two adjacent sets of inclined slots d. Each inclined slot d extends along the axial direction of the rotor core 10 and penetrates through its two end faces.

[0100] The inclined slot d can be regarded as a harmonic slot. The harmonic slot can effectively reduce the harmonic components during the operation of the motor, thereby reducing the harmonic loss and improving the overall efficiency of the motor. The harmonic slot can optimize the magnetic field distribution and improve the torque output of the motor, especially at low speeds. And it can effectively reduce the vibration and noise during the operation of the motor, improve the stability and comfort of the whole machine, balance the magnetic field on the rotor, and reduce the mechanical stress caused by imbalance.

[0101] By setting the harmonic slot, the performance, stability and working efficiency of the motor can be significantly improved, and it also helps to reduce noise and heat.

[0102] Further, please refer to Figure 3 , in this embodiment, a pair of magnets 20 are arranged in each magnet slot a. The central angle of the rotor core 10 corresponding to each pair of magnets 20 is Rfip; the inclined slot d has a third side wall 104 close to the corresponding groove b. P times the central angle of the rotor core 10 corresponding to the third side wall 104 is NAngleq; P times the included angle formed by the connection lines of the bottoms of the two inclined slots d in each group of inclined slots d and the center of the rotor core 10 is NAngleV; where, |Rfip - NAngleV - NAngleq| ≤ 5°.

[0103] One end of the two third side walls 104 in each group of inclined slots d close to the corresponding first slot section a1 corresponds to the central angle of the rotor core 10 as NAngle.

[0104] It should be noted that the central angle of the rotor core 10 corresponding to each pair of magnets 20 is Rfip: The "central angle" mentioned here refers to the angle between the center of the rotor core 10 and this pair of magnets 20. Rfip is a key parameter that affects the magnetic field distribution and the performance of the motor.

[0105] The inclined slot d has a third side wall 104 disposed near the corresponding recess b: The design of the inclined slot d includes a third side wall 104, which is the part near the recess b. The shape and position of this side wall are crucial for the performance of the motor and the formation of the magnetic field.

[0106] P times the central angle of the rotor core 10 corresponding to the third side wall 104 is NAngleq: NAngleq represents P times the central angle corresponding to the third side wall 104. P is a proportionality factor used to adjust this angle. This design parameter may be used to optimize the arrangement of the permanent magnet 20 and its relative position with respect to the rotor core 10.

[0107] P times the angle formed by the connection lines of the bottoms of two inclined slots d in each group of inclined slots d with the center of the rotor core 10 is NAngleV: Each group of inclined slots d has two slots, and the angle formed by the connection lines of their bottoms with the center of the rotor core 10 is called NAngleV. This means that the design of the inclined slots d takes into account the geometric relationship with the rotor core 10.

[0108] It should also be noted that |Rfip - NAngleV - NAngleq| ≤ 5°: This condition describes the relationship among the three angles, requiring that the difference between Rfip, NAngleV, and NAngleq does not exceed 5°. This limiting condition ensures that the angular configuration between the permanent magnet 20 and the inclined slot d is reasonable to optimize the magnetic field distribution and the overall performance of the motor.

[0109] By setting the difference between Rfip, NAngleV, and NAngleq not to exceed 5°, the geometric relationship and angular design among the magnet slot a, the inclined slot d, and the rotor core 10 are defined. Through a reasonable angular configuration, the magnetic field distribution of the motor can be optimized, thereby improving its performance and efficiency. And setting the difference between Rfip, NAngleV, and NAngleq not to exceed 5° ensures the coordination of the system, which may be to reduce imbalance, vibration, and noise, and to improve the stability and operating efficiency of the motor.

[0110] In this embodiment, the number of pole pairs of the motor rotor is P, 2 ≤ P ≤ 5. A higher number of pole pairs of the rotor (such as 5 pairs) can provide a smoother torque output and reduce torque ripple, which is particularly effective in applications requiring high speed and high power density. A lower number of pole pairs of the rotor (such as 2 pairs) is suitable for low-speed, high-torque applications, where a larger mechanical torque can be obtained. By setting the number of pole pairs in the range of greater than or equal to 2 and less than or equal to 5, the number of pole pairs can be flexibly selected according to specific application requirements to achieve the best performance and efficiency. For example, electric vehicles and high-efficiency servo motors usually select a higher number of pole pairs, while some industrial drives may select a lower number of pole pairs.

[0111] When the number of pole pairs P is excessive, i.e., P > 5, the design and manufacture of the iron core are complex, leading to increased costs and also an increase in losses in the magnetic circuit, reducing efficiency. For high-pole-number motors, the control algorithm may become complex, increasing the driving difficulty.

[0112] When the number of pole pairs P is too small, i.e., P < 2, the torque ripple increases, affecting the smooth operation of the motor. Under certain working conditions, the motor efficiency is not high, especially in applications that require efficient energy conversion. The lower number of pole pairs limits the speed range of the motor and is not suitable for high-speed applications.

[0113] Setting the number of pole pairs P between 2 and 5 can ensure the adaptability and efficiency of the motor under various application conditions while maintaining high performance.

[0114] Please refer to Figure 2 and Figure 3, in the first embodiment, 2P magnetic steel slots a extending along the axial direction of the rotor core 10 and penetrating through its two end faces are provided on the rotor core 10. The plurality of magnetic steel slots a are arranged at intervals along the circumferential direction of the rotor core 10. Each of the magnetic steel slots a has two first slot segments a1 extending along the radial direction of the rotor core 10, and the two first slot segments a1 are arranged to be away from each other in the direction away from the middle of the rotor core 10. Wherein, a plurality of V-shaped grooves are recessed on the outer peripheral edge of the rotor core 10. Each of the V-shaped grooves extends along the axial direction of the rotor core 10 and penetrates through its two end faces, and corresponds to the area between two adjacent magnetic steel slots a. 4P magnetic isolation slots c extending along the axial direction of the rotor core 10 and penetrating through its two end faces are further provided on the rotor core 10. The 4P magnetic isolation slots c are arranged at intervals along the circumferential direction of the rotor core 10. One magnetic isolation slot c is provided on one side of each first slot segment a1 close to the outer peripheral edge of the rotor core 10, and the magnetic isolation slot c is set to be approximately triangular. A pair of magnetic steels 20 are arranged in each of the magnetic steel slots a. The central angle Rfip of each pair of magnetic steels 20 corresponding to the center of the rotor core 10 is set to 136°. The included angle AngleV formed between the two first slot segments a1 is set to 142°. The distance d1 between the side wall of the magnetic isolation slot c close to the outer peripheral side of the rotor core 10 and the outer peripheral surface of the rotor core 10 in the radial direction of the rotor core 10 is set to 0.5 mm. The minimum gap d2 between the magnetic isolation slot c and the first slot segment a1 is set to 0.55 mm. The central angle Rfimbs1 of the rotor core 10 corresponding to the magnetic isolation slot c is set to 30°. The central angle Rfimbs2 of the rotor core 10 corresponding to the two magnetic isolation slots c located inside the magnetic steel slot a is set to 18°. The included angle Angle1 between the extending direction of the first side wall segment 101 and the extending direction of the corresponding first slot segment a1 is set to 49°. The included angle Angle2 between the extending direction of the second side wall segment 102 and the extending direction of the first slot segment a1 is set to 76°. A plurality of groups of inclined slots d are recessed on the outer peripheral edge of the rotor core 10. The plurality of groups of inclined slots d are distributed at intervals along the circumferential direction of the rotor core 10, and a groove b is provided between two adjacent groups of inclined slots d arranged adjacent to each other. Each of the inclined slots d extends along the axial direction of the rotor core 10 and penetrates through its two end faces.P times NAngleV of the included angle formed by the connection lines of the bottoms of the two inclined slots d in each group of the inclined slots d and the center of the rotor core 10 is set to 128°, P times NAngleq of the central angle of the rotor core 10 corresponding to the third side wall 104 of the inclined slot d is set to 6°, Rfip - NAngleV – Nangleq = 2°, meeting the requirement of |Rfip - NAngleV - NAngleq| ≤ 5°, and the width OBW of the first magnetic bridge section 1031 and the second magnetic bridge section 1032 is set to 0.5 mm.

[0115] Please refer to Figure 4, in the second embodiment, 2P magnetic steel slots a extending along the axial direction of the rotor core 10 and penetrating through its two end faces are provided on the rotor core 10, and the plurality of magnetic steel slots a are arranged at intervals along the circumferential direction of the rotor core 10. Each of the magnetic steel slots a has two first slot segments a1 extending along the radial direction of the rotor core 10, and the two first slot segments a1 are arranged to be away from each other in the direction away from the middle of the rotor core 10; wherein, a plurality of V-shaped slots are recessed on the outer peripheral edge of the rotor core 10, and each of the V-shaped slots extends along the axial direction of the rotor core 10 and penetrates through its two end faces, and corresponds to the area between two adjacent magnetic steel slots a; 4P magnetic isolation slots c extending along the axial direction of the rotor core 10 and penetrating through its two end faces are further provided on the rotor core 10, and the 4P magnetic isolation slots c are arranged at intervals along the circumferential direction of the rotor core 10. One magnetic isolation slot c is provided on one side of each first slot segment a1 close to the outer peripheral edge of the rotor core 10, and the magnetic isolation slot c is set to be triangular-like. A pair of magnetic steels 20 are arranged in each of the magnetic steel slots a. The central angle Rfip corresponding to each pair of magnetic steels 20 with respect to the center of the rotor core 10 is set to 136°, the included angle AngleV formed between the two first slot segments a1 is set to 142°, the distance d1 between the side wall of the magnetic isolation slot c close to the outer peripheral side of the rotor core 10 and the outer peripheral surface of the rotor core 10 in the radial direction of the rotor core 10 is set to 0.5 mm, the minimum gap d2 between the magnetic isolation slot c and the first slot segment a1 is set to 0.55 mm, the central angle Rfimbs1 of the rotor core 10 corresponding to the magnetic isolation slot c is set to 30°, the central angle Rfimbs2 of the rotor core 10 corresponding to the two magnetic isolation slots c located inside the magnetic steel slot a is set to 18°, the included angle Angle1 between the extending direction of the first side wall segment 101 and the extending direction of the corresponding first slot segment a1 is set to 49°, the included angle Angle2 between the extending direction of the second side wall segment 102 and the extending direction of the first slot segment a1 is set to 76°, and the width OBW of the first magnetic bridge segment 1031 and the second magnetic bridge segment 1032 is set to 0.5 mm. Compared with the first embodiment, in this embodiment, the rotor core 10 is not provided with an inclined slot d. For a rotor without an inclined slot d, by limiting the design parameters of the magnetic isolation slot c, the groove b and the magnetic steel slot a within the above ranges, the noise and performance of the motor can also be improved.

[0116] Please refer to Figure 5, in the third embodiment, 2P magnetic steel slots a are provided on the rotor core 10 and extend axially through its two end faces. The plurality of magnetic steel slots a are arranged at intervals along the circumferential direction of the rotor core 10. Each magnetic steel slot a has two first slot segments a1 extending radially along the rotor core 10, and the two first slot segments a1 are arranged to be away from each other in the direction away from the middle of the rotor core 10. Among them, a plurality of square slots are recessed on the outer peripheral edge of the rotor core 10. Each square slot extends axially through its two end faces and corresponds to the area between two adjacent magnetic steel slots a. 4P magnetic isolation slots c are also provided on the rotor core 10 and extend axially through its two end faces. The 4P magnetic isolation slots c are arranged at intervals along the circumferential direction of the rotor core 10. One magnetic isolation slot c is provided on one side of each first slot segment a1 close to the outer peripheral edge of the rotor core 10, and the magnetic isolation slot c is set to be rhomboid-like. A pair of magnetic steels 20 are arranged in each magnetic steel slot a. The central angle Rfip corresponding to each pair of magnetic steels 20 with respect to the center of the rotor core 10 is set to 136°, the included angle AngleV formed between the two first slot segments a1 is set to 142°, the distance d1 between the side wall of the magnetic isolation slot c close to the outer peripheral side of the rotor core 10 and the outer peripheral surface of the rotor core 10 in the radial direction of the rotor core 10 is set to 0.5 mm, the minimum gap d2 between the magnetic isolation slot c and the first slot segment a1 is set to 0.55 mm, the central angle Rfimbs1 of the rotor core 10 corresponding to the magnetic isolation slot c is set to 30°, the central angle Rfimbs2 of the rotor core 10 corresponding to the two magnetic isolation slots c located inside the magnetic steel slot a is set to 18°, the included angle Angle1 between the extending direction of the first side wall segment 101 and the extending direction of the corresponding first slot segment a1 is set to 49°, the included angle Angle2 between the extending direction of the second side wall segment 102 and the extending direction of the first slot segment a1 is set to 76°. A plurality of groups of inclined slots d are recessed on the outer peripheral edge of the rotor core 10. The plurality of groups of inclined slots d are arranged at intervals along the circumferential direction of the rotor core 10, and a groove b is provided between two adjacent groups of inclined slots d. Each inclined slot d extends axially through its two end faces.P times NAngleV of the included angle formed by the connection lines of the bottoms of two of the inclined slots d in each group of the inclined slots d and the center of the rotor core 10 is set to 128°, P times NAngleq of the central angle of the rotor core 10 corresponding to the third side wall 104 of the inclined slot d is set to 6°, Rfip - NAngleV – Nangleq = 2°, meeting the requirement of |Rfip - NAngleV - NAngleq| ≤ 5°, and the width OBW of the first magnetic bridge section 1031 and the second magnetic bridge section 1032 is set to 0.5 mm.

[0117] The present utility model also provides a motor, which includes a motor housing, a stator assembly and a rotor assembly. The specific structure of the rotor assembly refers to the above embodiments. Since this motor adopts all the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.

[0118] The above are only exemplary embodiments of the present utility model, and do not limit the patent scope of the present utility model. Any equivalent structural transformation made under the technical concept of the present utility model by using the content of the specification and drawings of the present utility model, or direct / indirect application in other related technical fields is included in the patent protection scope of the present utility model.

Claims

1. A rotor assembly, characterized in that: include: A rotor core, wherein the rotor core is provided with 2P magnetic steel slots extending along the axial direction thereof and penetrating through the two end surfaces thereof, the plurality of magnetic steel slots are arranged at intervals along the circumferential direction of the rotor core, each of the magnetic steel slots has two first slot sections extending along the radial direction of the rotor core, and the two first slot sections are arranged away from each other in a direction away from the middle of the rotor core; The outer periphery of the rotor core is provided with a plurality of grooves, each of which extends along the axial direction of the rotor core and penetrates through two end surfaces thereof, and corresponds to the area between two adjacent magnetic steel slots; The rotor core is also provided with 4P magnetic isolation grooves extending along the axial direction of the rotor core and penetrating its two end surfaces. The 4P magnetic isolation grooves are arranged at intervals along the circumference of the rotor core, and each of the first slot sections is provided with a magnetic isolation groove on one side close to the outer periphery of the rotor core.

2. The rotor assembly according to claim 1, characterized in that The side wall of the magnetic isolation groove close to the outer peripheral side of the rotor core is at a distance d1 from the outer peripheral surface of the rotor core in the radial direction of the rotor core, 0.4mm≤d1≤0.9mm; and / or, The minimum gap between the magnetic isolation groove and the first groove section is d2, 0.4mm≤d2≤0.6mm.

3. The rotor assembly according to claim 1, characterized in that The central angle of the rotor core corresponding to the magnetic isolation groove is Rfimbs1, 25°≤Rfimbs1≤35°; and / or, The central angle of the two magnetic isolation grooves located on the inner side of the magnetic steel groove corresponding to the rotor core is Rfimbs2, and 13°≤Rfimbs2≤23°.

4. The rotor assembly according to claim 1, wherein: Each of the first slot segments has an inner end close to another of the first slot segments, and an outer end away from another of the first slot segments; The magnetic isolation groove has a first end and a second end distributed in the circumferential direction of the rotor core, the first end of the magnetic isolation groove is arranged close to the outer end of the first groove segment, and the second end of the magnetic isolation groove is arranged close to the inner end of the first groove segment; The magnetic isolation slot comprises a first side wall and a second side wall connected between the first end and the second end, the first side wall is arranged close to the corresponding first slot segment, the second side wall is arranged close to the outer periphery of the rotor core, the first side wall comprises a first side wall segment, the second side wall comprises a second side wall segment, and the first side wall segment and the second side wall segment are arranged to be gradually opened from the first end to the second end of the magnetic isolation slot; The first side wall and the second side wall of the magnetic isolation groove have the largest corresponding opening angles at the first side wall section and the second side wall section; The angle between the extension direction of the first side wall segment and the corresponding extension direction of the first slot segment is Angle1, the angle between the extension direction of the second side wall segment and the extension direction of the first slot segment is Angle2, 44°≤Angle1≤54°, and 71°≤Angle2≤81°.

5. The rotor assembly according to claim 1, wherein: The groove is gradually expanded in the outward direction; and / or, The groove extends to a region between two adjacent magnetic steel grooves.

6. The rotor assembly according to claim 1, wherein: Each of the first slot segments has an inner end close to another slot segment and an outer end away from another first slot segment; The rotor assembly also includes a pair of magnetic steels arranged in each of the magnetic steel slots corresponding to the two first slot segments, an installation gap is reserved between the magnetic steels and the outer ends of the corresponding first slot segments, and an internal magnetic bridge is defined between the installation gap and the outer periphery of the rotor core.

7. The rotor assembly according to claim 6, characterized in that The inner magnetic bridge comprises a first magnetic bridge section and a second magnetic bridge section connected in sequence; The first magnetic bridge section is defined between the installation gap and the corresponding groove; The second magnetic bridge section is defined between the installation gap and the outer peripheral wall of the rotor core; The width OBW of the first magnetic bridge segment is set to be equivalent to that of the second magnetic bridge segment.

8. The rotor assembly according to claim 7, characterized in that A pair of magnetic steels is arranged in each magnetic steel slot, and the central angle of each pair of magnetic steels corresponding to the rotor core is Rfip, 130°≤Rfip≤139°; and / or, The angle formed between the two first groove sections is AngleV, and 110°≤AngleV≤155°.

9. The rotor assembly according to any one of claims 1 to 8, characterized in that: The outer periphery of the rotor core is provided with a plurality of groups of inclined grooves, which are spaced apart along the circumference of the rotor core, and a groove is provided between two adjacent groups of inclined grooves, and each inclined groove extends along the axial direction of the rotor core and passes through its two end faces.

10. The rotor assembly according to claim 9, characterized in that A pair of magnetic steels is arranged in each magnetic steel slot, and the central angle of the rotor core corresponding to each pair of magnetic steels is Rfip; The inclined slot has a third side wall arranged close to the corresponding groove, and the P times of the central angle of the rotor core corresponding to the third side wall is NAngleq; The angle formed by the bottom of the two inclined slots in each group of the inclined slots and the connecting line of the center of the rotor core is P times NAngleV; Among them, |Rfip-NAngleV-NAngleq|≤5°.

11. The rotor assembly according to any one of claims 1 to 10, characterized in that: 2≤P≤5。 12. A motor, characterized in that: Comprising a rotor assembly as claimed in any one of claims 1 to 11.

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