Rotor structure and electric machine
By setting multiple symmetrically distributed C-shaped magnet slots and multiple magnet segments on the rotor core, the magnetic field distribution is optimized, which solves the problem of difficult torque pulsation control in the motor rotor structure and improves the NVH performance of the motor.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- UNITED AUTOMOTIVE ELECTRONICS SYST
- Filing Date
- 2025-04-22
- Publication Date
- 2026-06-26
AI Technical Summary
Existing motor rotor topologies are difficult to effectively reduce torque ripple, especially in terms of multi-order torque fluctuation coordinated control, which leads to severe electromagnetic howling and affects NVH performance.
Design a rotor structure in which at least two layers of C-shaped magnet slots are arranged on the magnetic poles of the rotor core. Each layer of magnet slots includes symmetrically distributed closed magnet slots. Multiple magnet segments are arranged in each magnet slot. The magnetic field distribution is optimized by adjusting the slot width, slot shape and number of magnet segments to improve the continuity of the magnetic circuit and the harmonic distortion rate.
By optimizing the magnetic field distribution and harmonic suppression, torque pulsation is significantly reduced, improving the NVH performance of the motor, reducing vibration and noise, and increasing torque output capability and efficiency.
Smart Images
Figure CN224418529U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of motor manufacturing technology, and in particular relates to a rotor structure and a motor. Background Technology
[0002] Torque pulsation is a major source of electromagnetic noise in motors. Essentially, when the frequency of torque pulsation generated by the motor approaches the natural frequency of the structure, it triggers a severe resonance effect, leading to a bothersome electromagnetic howling phenomenon that significantly diminishes the user's driving experience. This issue not only tests the level of motor design but also directly relates to the NVH (noise, vibration, and harshness) performance of new energy vehicles.
[0003] To suppress torque ripple in motors, the industry has long been committed to optimizing rotor topology design to minimize torque ripple during the design phase, a persistent challenge. While traditional V-type, V-type, and double-V-type rotor structures can improve electromagnetic excitation by adjusting magnetic circuit distribution, they have inherent limitations in the coordinated control of multi-order torque ripples, making it difficult to simultaneously reduce torque ripples of multiple orders. The emerging 3V-type rotor topology, while able to further reduce torque ripple, offers only limited optimization effects. Utility Model Content
[0004] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a rotor structure and motor to solve the technical problem that the rotor topology of the motor in the prior art is difficult to effectively reduce torque pulsation.
[0005] To achieve the above and other related objectives, the technical solution of this utility model is as follows:
[0006] A rotor structure, comprising:
[0007] The rotor core has multiple magnetic poles evenly distributed along its circumference, and each magnetic pole is provided with at least two layers of magnetic steel slots. Each layer of magnetic steel slots has a C-shaped structure and includes two separate magnetic steel slots symmetrically distributed about the direct axis. The two ends of each magnetic steel slot are closed.
[0008] The magnet has multiple sections within each magnet slot.
[0009] Optionally, each of the magnetic poles is provided with three layers of magnetic steel slots, which are respectively the first layer of magnetic steel slots, the second layer of magnetic steel slots and the third layer of magnetic steel slots in the radial direction from the outer edge of the rotor core to the center. Each segment of magnet in the two magnetic steel slots in each layer of magnetic steel slots is respectively arranged in a one-to-one correspondence with respect to the straight axis.
[0010] Optionally, each of the magnet slots has two opposing slot walls, each slot wall comprising multiple straight segments and arc segments arranged along the extension direction of the slot wall, the straight segments being parallel to the sidewall of the magnet, and the arc segments connecting two adjacent straight segments.
[0011] Optionally, a protruding structure is provided between two adjacent sections of magnet in each magnet groove, and a closed groove is provided at both ends of the magnet groove. A protruding structure is also provided between the closed groove and the adjacent magnet. The protruding structure is located on the groove wall of the magnet groove and protrudes outward from the groove wall.
[0012] Optionally, the protrusion structure is located on the side wall of the magnet slot near the center of the rotor core, and the protrusion structure includes a main body and two opposing first side walls and second side walls disposed on the main body, the first side walls and the second side walls respectively abutting against two adjacent magnets.
[0013] Optionally, the slot width of the magnet slot group near the outer edge of the rotor core is smaller than the slot width of the magnet slot groups in the other layers, and at least two of the magnet slot groups in each layer have different slot widths.
[0014] Optionally, the magnets in the magnet slots of different layers have different shapes, and the magnets in each layer of the magnet slots have the same shape; the cross-sectional shape of the magnet along the axis perpendicular to the rotor core is rectangular.
[0015] Optionally, the number of magnet segments in each layer of the magnet slot group gradually increases along the direction close to the center of the rotor core.
[0016] Optionally, in the first layer of magnet slots, each magnet slot contains 1 to 4 magnet segments, the included angle between two adjacent magnet segments ranges from 5° to 15°, and the included angle between the first and last magnet segments ranges from 5° to 30°; in the second layer of magnet slots, each magnet slot contains 3 to 6 magnet segments, the included angle between two adjacent magnet segments ranges from 5° to 20°, and the included angle between the first and last magnet segments ranges from 10° to 60°; in the third layer of magnet slots, each magnet slot contains 4 to 8 magnet segments, the included angle between two adjacent magnet segments ranges from 5° to 20°, and the included angle between the first and last magnet segments ranges from 15° to 60°.
[0017] Based on the same concept, this utility model also provides an electric motor, including a stator and a rotor, wherein the rotor has the rotor structure described above.
[0018] As described above, the present invention has the following beneficial effects:
[0019] By setting at least two layers of magnetic steel slots on each magnetic pole of the rotor core, each layer of magnetic steel slots has a C-shaped structure and includes two separate magnetic steel slots symmetrically distributed about the direct axis. The two ends of each magnetic steel slot are closed, and multiple sections of magnets are set in each magnetic steel slot. This helps to improve the magnetic field circuit of the motor, reduce the harmonic distortion rate, thereby improving electromagnetic excitation, reducing motor torque pulsation, and achieving better NVH performance of the motor. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the structure of each pole of a rotor structure according to an embodiment of the present utility model;
[0021] Figure 2 for Figure 1 Enlarged view of part of the structure;
[0022] Figure 3 This is a schematic diagram of the structure of each pole of a 3V type rotor.
[0023] Figure 4 The figures show the torque pulsation waveforms of the rotor structure and the 3V-type rotor structure in the embodiments of this utility model.
[0024] Figure 5 This is a torque pulsation spectrum diagram of the rotor structure and the 3V type rotor structure in the embodiments of this utility model.
[0025] Explanation of reference numerals in the attached figures
[0026] 100 - Rotor core;
[0027] 10-Magnetic steel trough assembly; 11-First layer magnetic steel trough assembly; 12-Second layer magnetic steel trough assembly; 13-Third layer magnetic steel trough assembly; 14-Magnetic isolation bridge; 15-Enclosed trough section; 161-Straight section; 162-Circular arc section; 17-Protruding structure; 171-Main body; 172-First side wall; 173-Second side wall;
[0028] 20-Magnetic steel;
[0029] 100a - Rotor core; 10a - Magnet slot assembly; 20a - Magnet. Detailed Implementation
[0030] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.
[0031] It should be noted that the illustrations provided in this embodiment are merely schematic representations of the basic concept of this utility model. Therefore, the illustrations only show components relevant to this utility model and are not drawn according to the actual number, shape, and size of the components in implementation. In actual implementation, the form, quantity, and proportion of each component can be arbitrarily changed, and the component layout may be more complex. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to assist those skilled in the art in understanding and reading the content disclosed in the specification. They are not intended to limit the implementation conditions of this utility model and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this utility model, should still fall within the scope of the technical content disclosed in this utility model. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in this specification are only for clarity of description and are not intended to limit the scope of implementation of this utility model. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as within the scope of implementation of this utility model.
[0032] In order to describe this utility model in detail, the following is a specific description of one rotor structure of this utility model:
[0033] Please combine Figure 1 and Figure 2 As shown, this utility model provides a rotor structure, including: a rotor core 100 and magnets 20, wherein the rotor core 100 has multiple magnetic poles evenly distributed along its circumference, and each magnetic pole is provided with at least two layers of magnet slot groups 10, each layer of magnet slot group 10 has a C-shaped structure, and each layer of magnet slot group 10 includes two separate magnet slots symmetrically distributed about the direct axis (d-axis), and the two ends of each magnet slot are closed; the magnets 20 are provided with multiple segments in each magnet slot.
[0034] Specifically, the rotor core 100 consists of N poles and S poles symmetrically distributed circumferentially. Each magnetic pole is provided with at least two layers of magnetic slot groups 10. The multiple layers of magnetic slot groups 10 are beneficial to increasing the magnetic field strength and improving the torque density. Each layer of magnetic slot groups independently controls the harmonic components of different orders, which is beneficial to suppressing the torque pulsation of the motor. The two magnetic slots of each layer of magnetic slot groups 10 are symmetrically arranged about the direct axis (d-axis), and a magnetic isolation bridge 14 is provided between the two magnetic slots, which is beneficial to effectively counteract the imbalance of radial magnetic pull and reduce harmonic distortion caused by magnetic circuit asymmetry.
[0035] The C-shaped magnet slot group 10 can help guide the magnetic lines of force to be sinusoidally distributed along the surface of the rotor core 100, which helps to optimize the magnetic circuit, reduce leakage flux, thereby enhancing the torque output capability, making the magnetic field distribution more sinusoidal, reducing harmonics, and helping to reduce the torque pulsation of the motor.
[0036] Setting multiple sections of magnet 20 in each magnet slot can reduce eddy current losses, improve efficiency, reduce local overheating, and improve the heat dissipation performance of magnet 20.
[0037] The above structure can improve the magnetic field circuit of the motor, reduce the harmonic distortion rate, thereby improving electromagnetic excitation, reducing motor torque pulsation, and achieving better NVH (noise, vibration, and harshness) performance of the motor.
[0038] In some embodiments, each magnetic pole is provided with three layers of magnetic slot groups 10, which are respectively the first layer of magnetic slot group 11, the second layer of magnetic slot group 12, and the third layer of magnetic slot group 13 in the radial direction from the outer edge of the rotor core 100 towards the center. Each segment of magnet 20 in the two magnetic slots of each layer of magnetic slot group 10 is respectively arranged in a one-to-one correspondence with respect to the direct axis. Specifically, on each magnetic pole of the rotor core 10, the first layer of magnetic slot group 11, the second layer of magnetic slot group 12, and the third layer of magnetic slot group 13 are arranged from the outside to the inside. The three layers of magnetic slot groups 10 form a magnetic potential superposition region in the radial direction, which is conducive to the formation of a radial magnetic flux density gradient. Through the multi-layer arrangement of magnetic slot groups 10, multi-order torque pulsations can be suppressed in layers, thereby achieving the effect of synergistic suppression of multi-order torque pulsations. Each layer of magnet slot group 10 includes two magnet slots symmetrically arranged about the direct axis, and each segment of magnet 20 in the two magnet slots is arranged in a one-to-one correspondence about the direct axis, which helps to balance radial force, reduce vibration and noise, and improve the continuity of magnetic circuit.
[0039] In some embodiments, each magnet slot has two opposing slot walls. Each slot wall includes multiple straight segments 161 and arc segments 162 extending along the slot wall direction. The straight segments 161 are parallel to the sidewall of the magnet 20, and the arc segments 162 connect adjacent straight segments 161. Specifically, each magnet slot has a C-shaped structure composed of multiple straight segments 161 and arc segments 162. The slot wall of each magnet slot includes multiple straight segments 161 and arc segments 162. Each straight segment 161 is parallel to the sidewall of the magnet 20 to fit against the magnet 20, adapting to the installation of the magnet 20, facilitating the positioning of the magnet 20, and enhancing the magnet 20's anti-centrifugal force. Simultaneously, it also facilitates the formation of an axial guiding channel for magnetic field lines, enhancing the directionality of the main magnetic flux. The arc segments 162 between adjacent straight segments 161 help reduce stress concentration. In addition, the alternating structure of straight segment 161 and circular arc segment 162 is also beneficial for cutting off the circumferential vortex flow path.
[0040] It should be noted that a protruding structure 17 is provided between two adjacent sections of magnet 20 in each magnet groove, and a closed groove portion 15 is provided at each end of the magnet groove. A protruding structure 17 is also provided between the closed groove portion 15 and the adjacent magnet 20. The protruding structure 17 is located on the groove wall of the magnet groove and protrudes outward from the groove wall. Specifically, the protruding structure 17 is provided between two adjacent sections of magnet 20 in each magnet groove, and between the closed groove portion 15 and the adjacent magnet 20, to restrict the movement of the magnet 20, thereby facilitating the limiting of the magnet 20, enhancing the stability of the magnet 20, improving the anti-centrifugal force of the magnet 20, and preventing the magnet 20 from displacing due to centrifugal force.
[0041] In the above embodiment, the protruding structure 17 is located on the side wall of the magnet slot near the center of the rotor core 100, and the protruding structure 17 includes a main body 171 and two opposing first sidewalls 172 and second sidewalls 173 disposed on the main body 171. The first sidewalls 172 and second sidewalls 173 respectively abut against two adjacent magnets 20. Specifically, the protruding structure 17 is located on the side wall of the magnet slot near the center of the rotor core 100, which facilitates better positioning of the magnets 20 and improves the anti-centrifugal force of the magnets 20. By having the first sidewalls 172 and second sidewalls 173 on the main body 171 abut against adjacent magnets 20, the radial fixing stability can be enhanced, preventing displacement of the magnets 20 during high-speed rotation.
[0042] In some embodiments, the slot width of the magnet slot group 10 near the outer edge of the rotor core 100 is smaller than the slot width of the other layers of magnet slot groups 10, and at least two layers of magnet slot groups 10 have different slot widths. Specifically, in this example, the slot width of the first layer of magnet slot group 11 is smaller than the slot width of the second layer of magnet slot group 12 and also smaller than the slot width of the third layer of magnet slot group 13, and the slot widths of the first layer of magnet slot group 11, the second layer of magnet slot group 12, and the third layer of magnet slot group 13 increase sequentially. By using a smaller slot width for the outer edge magnet slot group 10, it is beneficial to increase the magnetic circuit reluctance, reduce edge magnetic flux saturation, reduce leakage flux, and optimize the magnetic field distribution; by using a larger slot width for the inner layer magnet slot group 10, it is beneficial to enhance the main magnetic flux carrying capacity; in addition, the outer edge uses a narrower magnet slot group 10 to improve the resistance to centrifugal force, and the inner layer uses a wider magnet slot group 10 to enhance the overall resistance to deformation. This layered slot width structure helps suppress harmonic phase superposition, thereby reducing multi-order comprehensive torque pulsation, and thus reducing vibration and noise.
[0043] It should be noted that the magnets 20 in different layers of the magnet slot group 10 have different shapes, while the magnets 20 in each layer of the magnet slot group 10 have the same shape; the cross-sectional shape of the magnet 20 along the axis perpendicular to the rotor core 100 is rectangular. Specifically, in this example, the thickness of the magnets 20 (adapted to the slot width) in the first layer of the magnet slot group 11, the second layer of the magnet slot group 12, and the third layer of the magnet slot group 13 increases sequentially to optimize the magnetic field distribution and reduce magnetic leakage. Having the same shape for the magnets 20 in the same layer of the magnet slot group 10 helps ensure uniform stress distribution, improves structural reliability, and contributes to consistency in manufacturing and assembly, thereby improving production efficiency. In other embodiments, the shapes of the magnets 20 in the same layer of the magnet slot group 10 can also be different, thereby better mitigating torque fluctuations.
[0044] In the above embodiment, the number of magnet segments 20 in each layer of magnet slot group 10 gradually increases along the direction close to the center of the rotor core 100. In this way, more magnet segments 20 are arranged in the magnet slot group 10 close to the center of the rotor core 100, forming a gradient structure to cope with higher centrifugal force and optimize the magnetic field distribution.
[0045] In the above embodiment, each magnet slot in the first layer of magnet slot group 11 contains 1 to 4 magnet segments 20, the included angle between two adjacent magnet segments 20 ranges from 5° to 15°, and the included angle between the first and last magnet segments 20 ranges from 5° to 30°. This structure, with fewer magnet segments 20 and a smaller included angle between adjacent magnet segments 20, helps reduce magnetic leakage and improve the efficiency of the magnetic circuit; the included angle between the first and last magnet segments 20 helps adjust the symmetry of the magnetic field and reduce torque pulsation.
[0046] In the second layer of the magnetic steel trough group 12, each magnetic steel trough contains 3 to 6 sections of magnets 20. The included angle between two adjacent sections of magnets 20 ranges from 5° to 20°, and the included angle between the first and last sections of magnets 20 ranges from 10° to 60°. This structure, with its expanded range of included angles between adjacent sections of magnets 20, helps to optimize performance at different speeds and adapt to higher centrifugal forces.
[0047] In the third layer of magnet slot group 13, each magnet slot contains 4 to 8 magnet segments 20. The included angle between two adjacent magnet segments 20 ranges from 5° to 20°, and the included angle between the first and last magnet segments 20 ranges from 15° to 60°. Increasing the number of magnet segments 20 enhances the magnetic field modulation capability, thereby optimizing the overall torque output.
[0048] By gradually increasing the number of magnet segments, the sinusoidal nature of the magnetic field can be improved, and harmonics can be reduced. The outer layer has fewer segments and smaller angles, while the inner layer has more segments and larger angles, which can form a gradient structure, thereby optimizing the overall performance of the magnetic field distribution of the rotor core 100 and reducing torque pulsation.
[0049] Let's take an 8-pole, 48-slot motor as an example to illustrate the optimization effect of this rotor structure on torque ripple. For example... Figure 1 As shown, it is a schematic diagram of the rotor structure of this utility model per pole (referred to as the segmented 3C type rotor structure); Figure 3 This is a schematic diagram of each pole structure of the existing 3V rotor structure. Figure 3 In the rotor core 100a, each pole has three layers of magnet slot groups 10a, and each magnet slot group 10a is approximately V-shaped. Each magnet slot group 10a contains one section of magnet 20a. The peak torque pulsation of the two motors is simulated under the same boundary conditions, such as... Figure 4 The image shows the waveforms of torque pulsation in two motors. Figure 4 The solid line in the middle represents the torque pulsation waveform of the segmented 3C type rotor structure. Figure 4 The dashed line represents the torque pulsation waveform of the 3V rotor structure; Figure 5 The images show the Fourier decomposition spectra of the torque ripple of the two motors. It can be seen that the rotor structure proposed in this invention significantly reduces the torque ripple of the motor compared to the 3V rotor structure. Specifically, the 24th-order torque ripple is reduced by 8%, the 48th-order main order is reduced by 53%, and the 72nd and 96th-order high-order torque ripples show no deterioration, demonstrating a significant improvement effect.
[0050] Based on the same concept, this utility model also provides an electric motor, including a stator and a rotor, wherein the rotor has the rotor structure as described above.
[0051] In summary, the rotor structure and motor provided by this utility model, by setting at least two layers of magnetic steel slot groups 10 on each magnetic pole of the rotor core 100, each layer of magnetic steel slot group 10 has a C-shaped structure and includes two separate magnetic steel slots symmetrically distributed about the direct axis. The two ends of each magnetic steel slot are closed, and multiple sections of magnets 20 are set in each magnetic steel slot. This is beneficial to improve the magnetic field circuit of the motor, reduce the harmonic distortion rate, thereby improving electromagnetic excitation, reducing motor torque pulsation, and achieving better NVH performance of the motor.
[0052] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.
Claims
1. A rotor structure, characterized by, include: The rotor core has multiple magnetic poles evenly distributed along its circumference, and each magnetic pole is provided with at least two layers of magnetic steel slots. Each layer of magnetic steel slots has a C-shaped structure and includes two separate magnetic steel slots symmetrically distributed about the direct axis. The two ends of each magnetic steel slot are closed. The magnet has multiple sections within each magnet slot.
2. A rotor structure according to claim 1, wherein Each of the magnetic poles is provided with three layers of magnetic steel slots, which are the first layer of magnetic steel slots, the second layer of magnetic steel slots, and the third layer of magnetic steel slots in the radial direction from the outer edge of the rotor core to the center. In each layer of magnetic steel slots, the sections of magnets in the two magnetic steel slots are respectively arranged in a one-to-one correspondence with the straight axis.
3. A rotor construction according to claim 1 or 2, characterised in that Each of the magnet slots has two opposing slot walls, each slot wall comprising multiple straight segments and arc segments extending along the slot wall direction, the straight segments being parallel to the sidewalls of the magnet, and the arc segments connecting adjacent straight segments.
4. A rotor structure according to claim 3, wherein A protruding structure is provided between two adjacent sections of magnet in each magnet groove. A closed groove is provided at each end of the magnet groove. A protruding structure is also provided between the closed groove and the adjacent magnet. The protruding structure is located on the groove wall of the magnet groove and protrudes outward from the groove wall.
5. A rotor structure according to claim 4, wherein The protruding structure is located on the side wall of the magnet slot near the center of the rotor core, and the protruding structure includes a main body and two opposing first and second side walls disposed on the main body, the first and second side walls respectively abutting against two adjacent magnets.
6. A rotor structure according to claim 1 or 2, characterised in that The slot width of the magnet slot group near the outer edge of the rotor core is smaller than the slot width of the magnet slot groups in the other layers, and at least two of the magnet slot groups in each layer have different slot widths.
7. A rotor structure according to claim 1 or 2, characterised in that The magnets in the magnet slots of different layers have different shapes, while the magnets in each layer of the magnet slots have the same shape; the cross-sectional shape of the magnet along the axis perpendicular to the rotor core is rectangular.
8. A rotor structure according to claim 1 or 2, characterised in that Along the direction closer to the center of the rotor core, the number of magnet segments in each layer of the magnet slot group gradually increases.
9. A rotor structure according to claim 2, wherein In the first layer of magnet slots, each magnet slot contains 1 to 4 magnet segments, with the included angle between two adjacent magnet segments ranging from 5° to 15°, and the included angle between the first and last magnet segments ranging from 5° to 30°. In the second layer of magnet slots, each magnet slot contains 3 to 6 magnet segments, with the included angle between two adjacent magnet segments ranging from 5° to 20°, and the included angle between the first and last magnet segments ranging from 10° to 60°. In the third layer of magnet slots, each magnet slot contains 4 to 8 magnet segments, with the included angle between two adjacent magnet segments ranging from 5° to 20°, and the included angle between the first and last magnet segments ranging from 15° to 60°.
10. An electric machine characterized by It includes a stator and a rotor, wherein the rotor is a rotor structure as described in any one of claims 1-9.