Motor rotor and permanent magnet motor
By optimizing the angle and size of the permanent magnet on the iron core and combining the magnetic isolation bridge design, the problem of increasing material costs of permanent magnet motors is solved, and the motor performance and cost savings are achieved.
Patent Information
- Application Number
- CN202422383963.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-29
- Publication Date
- 2025-09-02
- Estimated Expiration
- 2034-09-29
AI Technical Summary
In existing permanent magnet motors, larger size permanent magnets are required to improve performance, resulting in increased material costs.
By optimizing the inclination angle and size of V-shaped and single-shaped permanent magnets on the core, combining the magnetic isolation bridge design and silicon steel sheet iron core, a multi-pole motor is formed to increase the permanent magnet magnetic flux and magnetoresistive torque and reduce material use.
Without increasing material costs, the torque and power density of the motor are improved, the vibration and noise of the motor are reduced, and the motor performance is optimized.
Smart Images
Figure CN223297428U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of permanent magnet motors, and in particular relates to a motor rotor and a permanent magnet motor. Background Art
[0002] The main structural difference between permanent magnet motors and induction motors lies in the rotor. While the rotor of an induction motor primarily consists of an iron core and windings, the rotor of a permanent magnet motor primarily consists of an iron core and permanent magnets. Currently, to improve motor performance, larger permanent magnets are often required. However, permanent magnets are expensive and require a large quantity, significantly increasing motor costs. Utility Model Content
[0003] The present application provides a motor rotor that can improve motor performance without increasing material costs.
[0004] The utility model is realized through the following technical solutions: a motor rotor, comprising:
[0005] An iron core, wherein a permanent magnet unit is embedded in the iron core; the permanent magnet unit includes a V-shaped magnet;
[0006] The V-shaped magnet includes two bar-shaped permanent magnets, which are symmetrically distributed along the d axis on the cross section of the iron core and form a V shape with the opening facing the outer periphery of the iron core;
[0007] On the cross section of the iron core, the electrical angle between the line connecting the near vertex of the bar permanent magnet and the center point of the iron core and the d-axis is a first electrical angle, where the near vertex refers to the vertex closest to the outer periphery of the iron core, and the value range of the first electrical angle is 55.4° to 59.4°;
[0008] On the cross section of the core, a mechanical angle is formed between the long side of the bar-shaped permanent magnet and the d-axis, and the value range of the mechanical angle is 52.1 to 58.1°.
[0009] The utility model improves the motor performance and increases the motor torque by optimizing the inclination angle of the V-shaped magnet, does not need to increase the size of the permanent magnet, and saves material costs.
[0010] Furthermore, the permanent magnet unit also includes a straight permanent magnet arranged at the opening of the V-shaped magnet; on the cross section of the iron core, the midline of the straight permanent magnet coincides with the d-axis; the electrical angle between the line connecting the near vertex on the end face of the straight permanent magnet and the center point of the iron core and the d-axis is a second electrical angle, and the value range of the second electrical angle is 31.25~35.25°.
[0011] The permanent magnet unit composed of V-shaped magnets and straight permanent magnets can provide a larger permanent magnet flux linkage, increase the d-axis magnetic resistance, and improve the magnetic resistance torque, that is, increase the torque and power density, and further improve the motor performance.
[0012] Furthermore, the permanent magnet units are circumferentially and evenly spaced on the cross section of the core. The circumferential distribution of the permanent magnet units forms a multi-pole motor. The number of permanent magnet units determines the number of magnetic poles of the motor. Increasing the number of magnetic poles can increase the motor torque.
[0013] Furthermore, the outer diameter of the iron core is 49.5 to 53.5 mm. For motors with an outer diameter of the iron core of 49.5 to 53.5 mm, in order to balance motor performance and cost, the present invention optimizes the size of the permanent magnet as follows:
[0014] The cross section of the bar permanent magnet is rectangular; the long side of the cross section of the bar permanent magnet is 11.5 to 13.5 mm; the short side of the cross section of the bar permanent magnet is 3.1 to 4.1 mm; and the distance from the near vertex of the bar permanent magnet to the center point of the iron core is 47.9 to 51.9 mm.
[0015] The cross section of the I-shaped permanent magnet is rectangular; the short side length of the cross section of the I-shaped permanent magnet is 1.7-2.7 mm; the distance from the near vertex of the I-shaped permanent magnet to the center point of the iron core is 48-52 mm.
[0016] In order to take into account both motor performance and mechanical strength, this utility model adopts a magnetic isolation bridge design:
[0017] The two side grooves of the V-shaped groove on the iron core for embedding the V-shaped magnet are separated by a magnetic isolation bridge on the iron core; the center line of the magnetic isolation bridge coincides with the d-axis, and the width of the magnetic isolation bridge is 0.8 to 1.2 mm.
[0018] Furthermore, when the outer diameter of the iron core increases or decreases, the straight permanent magnet, the bar permanent magnet and the magnetic isolation bridge are scaled in equal proportion based on the center of the iron core.
[0019] Furthermore, the iron core is made of laminated silicon steel sheets. The iron core made of silicon steel sheets can reduce eddy current loss.
[0020] Furthermore, a harmonic groove is provided on the outer circumference of the core. The cross-section of the harmonic groove is semicircular, the center of the groove is 0.8 to 1.2 mm from the q-axis, and the radius of the harmonic groove is 0.4 to 0.6 mm. The harmonic groove can reduce the vibration and noise of the motor while maintaining the performance.
[0021] The utility model also provides a permanent magnet motor, comprising the motor rotor.
[0022] The utility model improves the motor performance without increasing the material cost by optimizing the inclination angle of the permanent magnet on the iron core; and takes into account both the motor performance and the cost by optimizing the size of the permanent magnet. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0024] Figure 1 is a schematic cross-sectional view of the motor rotor in this specific embodiment;
[0025] Figure 2 is a diagram marking the inclination angle of the permanent magnet unit in this specific embodiment;
[0026] Figure 3 is a dimensioned diagram of the permanent magnet unit in this specific embodiment;
[0027] Figure 4 It is a dimensioned diagram of the iron core in this specific embodiment. DETAILED DESCRIPTION
[0028] The following is a clear and complete description of the technical solutions in this application in conjunction with the accompanying drawings. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.
[0029] This specific embodiment provides a motor rotor that can improve motor performance without increasing material costs.
[0030] refer to Figure 1 and Figure 2 As shown, a motor rotor includes:
[0031] An iron core 1, wherein a permanent magnet unit is embedded in the iron core 1; the permanent magnet unit comprises a V-shaped magnet;
[0032] The V-shaped magnet includes two bar-shaped permanent magnets 2, which are symmetrically distributed along the d axis on the cross section of the iron core 1 and form a V shape with the opening facing the outer periphery of the iron core 1;
[0033] On the cross section of the core 1, the electrical angle between the line connecting the near vertex of the bar permanent magnet 2 and the center point of the core 1 and the d-axis is a first electrical angle α, where the near vertex refers to the vertex closest to the outer periphery of the core 1, and the value range of the first electrical angle α is 55.4-59.4°;
[0034] On the cross section of the core 1 , a mechanical angle is formed between the long side of the bar-shaped permanent magnet 2 and the d-axis. The value range of the mechanical angle is 52.1 to 58.1°. The angle γ in the figure is the complementary angle of the mechanical angle.
[0035] The d-axis, also known as the direct axis, is the centerline of the rotor's north pole. The quadrature axis, 90° electrical angle ahead of the d-axis, is the q-axis. However, the mechanical angle between the d-axis and the q-axis is not necessarily 90°, as electrical angle = mechanical angle * number of motor pole pairs. In this specific embodiment, the number of permanent magnet poles is 8, while the number of permanent magnet pole pairs is 4, and the number of motor pole pairs is 4.
[0036] When installing V-shaped magnets, it is necessary to convert the electrical angle into the corresponding mechanical angle based on the number of motor pole pairs, that is, the number of pole pairs of the permanent magnet unit.
[0037] This specific embodiment improves motor performance and increases motor torque by optimizing the tilt angle of the V-shaped magnet, without increasing the size of the permanent magnet, thus saving material costs.
[0038] The permanent magnet unit also includes a straight-line permanent magnet 3 arranged at the opening of the V-shaped magnet; on the cross section of the iron core 1, the midline of the straight-line permanent magnet 3 coincides with the d-axis; the electrical angle between the line connecting the near vertex on the end face of the straight-line permanent magnet 3 and the center point of the iron core 1 and the d-axis is a second electrical angle β, and the value range of the second electrical angle β is 31.25~35.25°.
[0039] When installing the inline permanent magnet 3 , it is necessary to convert the electrical angle into the corresponding mechanical angle according to the number of motor pole pairs, that is, the number of pole pairs of the permanent magnet unit.
[0040] The permanent magnet unit composed of a V-shaped magnet and a straight permanent magnet 3 can provide a larger permanent magnet flux linkage, increase the d-axis magnetic resistance, and improve the magnetic resistance torque, that is, increase the torque and power density, and further improve the motor performance.
[0041] The permanent magnet units are evenly spaced circumferentially on the cross section of the core 1. The circumferential distribution of the permanent magnet units forms a multi-pole motor. The number of permanent magnet units determines the number of magnetic poles of the motor. Increasing the number of magnetic poles can increase the motor torque.
[0042] refer to Figure 3As shown, in this specific embodiment, the outer diameter D of the core 1 is 49.5 to 53.5 mm. For a motor with an outer diameter of the core 1 of 49.5 to 53.5 mm, in order to balance motor performance and cost, this specific embodiment optimizes the size of the permanent magnet as follows:
[0043] refer to Figure 4 As shown, the cross section of the bar permanent magnet 2 is rectangular; the long side L1 of the cross section of the bar permanent magnet 2 is 11.5 to 13.5 mm; the short side W1 of the cross section of the bar permanent magnet 2 is 3.1 to 4.1 mm; and the distance d1 from the near vertex of the bar permanent magnet 2 to the center point of the iron core 1 is 47.9 to 51.9 mm.
[0044] refer to Figure 4 As shown, the cross section of the I-shaped permanent magnet 3 is rectangular; the short side length W2 of the cross section of the I-shaped permanent magnet 3 is 1.7-2.7 mm; and the distance d2 from the near vertex of the I-shaped permanent magnet 3 to the center point of the core 1 is 48-52 mm.
[0045] In order to balance motor performance and mechanical strength, this specific implementation adopts a magnetic isolation bridge design:
[0046] refer to Figure 3 As shown, the two side grooves of the V-shaped groove on the iron core 1 for embedding the V-shaped magnet are separated by the magnetic isolation bridge on the iron core 1; the center line of the magnetic isolation bridge coincides with the d-axis; the width c1 of the magnetic isolation bridge is 0.8-1.2 mm.
[0047] When the outer diameter of the iron core 1 increases or decreases, the straight permanent magnet 3 , the bar permanent magnet 2 and the magnetic isolation bridge are scaled in equal proportion based on the center of the iron core 1 .
[0048] The iron core 1 is made of laminated silicon steel sheets, which can reduce eddy current loss.
[0049] refer to Figure 1 and 3 As shown, a harmonic slot 4 is provided on the outer circumference of the core. The cross-section of the harmonic slot 4 is semicircular, and the distance c2 from the center of the harmonic slot 4 to the q-axis is 0.8 to 1.2 mm. The radius r of the harmonic slot 4 is 0.4 to 0.6 mm. The harmonic slot can reduce vibration and noise while maintaining motor performance.
[0050] This specific embodiment also provides a permanent magnet motor, including the motor rotor in this specific embodiment.
[0051] The parameters of the permanent magnet motor in this specific embodiment are as follows: the outer diameter of the iron core 1 is 51.5 mm; the first electrical angle α is 57.4°; the mechanical angle is 55.1°; the second electrical angle β is 33.3°; the long side of the cross section of the bar permanent magnet 2 is 12.5 mm; the short side of the cross section of the bar permanent magnet 2 is 3.6 mm; the distance from the near vertex of the bar permanent magnet 2 to the center point of the iron core 1 is 49.9 mm; the cross section of the I-shaped permanent magnet 3 is rectangular; the short side length of the cross section of the I-shaped permanent magnet 3 is 2.2 mm; the distance from the near vertex of the I-shaped permanent magnet 3 to the center point of the iron core 1 is 50 mm; the width of the magnetic isolation bridge is 1 mm.
[0052] In order to better illustrate the improvement effect of the present invention on motor performance, three motors were used for simulation analysis. Motor 1 is the permanent magnet motor in this specific embodiment. The difference between motor 2 and motor 1 is only in the first electrical angle α. The difference between motor 3 and motor 1 is only in the second electrical angle β. The simulation analysis results are shown in the following table:
[0053] Motor performance comparison table
[0054] The first electrical angle α The second electrical angle β Torque value Torque ripple Motor 1 57.4° 33.3° 274.1Nm 2.4％ Motor 2 61.4° 33.3° 261.8Nm 6.6％ Motor 3 57.4° 30.4° 261.8Nm 3.5％
[0055] As can be seen from the table, motor 1 has the highest torque value and the lowest torque fluctuation (optimal NVH performance). The electrical angles of motors 2 and 3 are both outside the angle range provided by the present invention. Motor 1 has improved motor performance compared to motors 2 and 3. This shows that by optimizing the tilt angle of the permanent magnet on the core 1, motor performance can be improved without increasing material costs.
[0056] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of this application.
Claims
1. A motor rotor, characterized in that: include: An iron core, wherein a permanent magnet unit is embedded in the iron core; the permanent magnet unit includes a V-shaped magnet; The V-shaped magnet includes two bar-shaped permanent magnets, which are symmetrically distributed along the d axis on the cross section of the iron core and form a V shape with the opening facing the outer periphery of the iron core; On the cross section of the iron core, the electrical angle between the line connecting the near vertex of the bar permanent magnet and the center point of the iron core and the d-axis is a first electrical angle, where the near vertex refers to the vertex closest to the outer periphery of the iron core, and the value range of the first electrical angle is 55.4° to 59.4°; On the cross section of the core, a mechanical angle is formed between the long side of the bar-shaped permanent magnet and the d-axis, and the value range of the mechanical angle is 52.1 to 58.1°.
2. The motor rotor according to claim 1, characterized in that: The permanent magnet unit also includes a straight-line permanent magnet arranged at the opening of the V-shaped magnet; on the cross section of the iron core, the midline of the straight-line permanent magnet coincides with the d-axis; the electrical angle between the line connecting the near vertex on the end face of the straight-line permanent magnet and the center point of the iron core and the d-axis is a second electrical angle, and the value range of the second electrical angle is 31.25~35.25°.
3. The motor rotor according to claim 1 or 2, characterized in that: The permanent magnet units are circumferentially distributed at equal intervals on the cross section of the core.
4. The motor rotor according to claim 3, characterized in that: The first electrical angle is 57.4°; the mechanical angle is 55.1°.
5. The motor rotor according to claim 2, characterized in that: The second electrical angle is 33.3°.
6. The motor rotor according to claim 3, characterized in that: The outer diameter of the iron core is 49.5-53.5 mm.
7. The motor rotor according to claim 6, characterized in that: The cross section of the bar permanent magnet is rectangular; the long side of the cross section of the bar permanent magnet is 11.5 to 13.5 mm; the short side of the cross section of the bar permanent magnet is 3.1 to 4.1 mm; and the distance from the near vertex of the bar permanent magnet to the center point of the iron core is 47.9 to 51.9 mm.
8. The motor rotor according to claim 2, characterized in that: The cross section of the I-shaped permanent magnet is rectangular; the short side length of the cross section of the I-shaped permanent magnet is 1.7 to 2.7 mm; the distance from the near vertex of the I-shaped permanent magnet to the center point of the iron core is 48 to 52 mm.
9. The motor rotor according to claim 8, characterized in that: The two side grooves of the V-shaped groove on the iron core for embedding the V-shaped magnet are separated by a magnetic isolation bridge on the iron core; the center line of the magnetic isolation bridge coincides with the d-axis; and the width of the magnetic isolation bridge is 0.8-1.2 mm.
10. The motor rotor according to claim 9, characterized in that: When the outer diameter of the iron core increases or decreases, the straight permanent magnet, the bar permanent magnet and the magnetic isolation bridge are scaled in equal proportion based on the center of the iron core.
11. The motor rotor according to claim 1, characterized in that: The iron core is formed by laminating silicon steel sheets.
12. The motor rotor according to claim 1, characterized in that: A harmonic groove is provided on the outer peripheral surface of the iron core. The cross section of the harmonic groove is semicircular. The center position of the harmonic groove is 0.8 to 1.2 mm away from the q axis. The radius of the harmonic groove is 0.4 to 0.6 mm.
13. A permanent magnet motor, characterized in that: It comprises the motor rotor as claimed in any one of claims 1 to 12.