Rotor assembly and motor

Abstract

The invention provides a rotor assembly and a motor. The rotor assembly includes: a rotor body extending in an axial direction and having a circular cross-section in the axial direction, the circular cross-section having a first radius; the plurality of magnetic steel stacked bodies are arranged on the outer surface of the rotor body; wherein in the axial direction, the cross section of the magnetic steel stacking body comprises a first edge and a second edge, the first edge faces the rotor body and has a first radius, and the second edge deviates from the rotor body and has a second radius; and wherein the center of circle of the contour of the first edge is substantially concentric with the center of circle of the outer contour of the rotor body, and the second center of circle of the contour of the second edge is spaced apart from the first center of circle of the contour of the first edge by an eccentric distance. The rotor assembly and the motor have the advantages of being simple in structure, easy to implement, convenient to use and the like, and the noise performance of the motor is improved.

Description

Technical Field

[0001] The present application relates to the field of motor structures. More specifically, the present application relates to a rotor assembly, which is intended to improve the noise performance of the motor. The present application also relates to a motor, which includes the above-mentioned rotor assembly. Background Art

[0002] Due to its advantages of high torque density, high efficiency, wide speed range, etc., permanent magnet synchronous motors are widely used in automobiles, industry, etc. At present, permanent magnet synchronous motors are developing towards high efficiency and low noise.

[0003] In traditional built-in permanent magnet synchronous motors, the magnets are embedded in the rotor core, which needs to be slotted. The magnetomotive force harmonic content is richer, and it is difficult to suppress the cogging torque, ripple torque and back-electromotive force harmonic distortion rate. Compared with built-in permanent magnet synchronous motors, the magnets of surface-mounted permanent magnet synchronous motors are directly pasted on the surface of the rotor core. The rotor does not need to be slotted, and the magnetomotive force harmonic content is low. By optimizing parameters such as the pole shape, pole arc coefficient, and magnet skew, the noise of the surface-mounted permanent magnet synchronous motor can be improved to a certain extent. In the prior art, the optimization usually focuses on one or two of the above parameters. For example, single factors such as cogging torque and torque pulsation can be optimized. Summary of the invention

[0004] One aspect of the present application is to provide a rotor assembly, which reduces noise through appropriate component arrangement. Another aspect of the present application is to provide an electric machine, which includes the rotor assembly.

[0005] The purpose of this application is achieved through the following technical solutions: A rotor assembly, comprising: a rotor body extending in an axial direction and having a circular cross section in the axial direction, wherein the circular cross section has a first radius; A plurality of magnetic steel stacks, wherein the magnetic steel stacks are arranged on the outer surface of the rotor body; Wherein, in the axial direction, the cross section of the magnetic steel stack includes a first edge and a second edge, the first edge faces toward the rotor body and has a first radius, and the second edge faces away from the rotor body and has a second radius; and The center of the contour of the first edge is substantially concentric with the center of the outer contour of the rotor body, and the second center of the contour of the second edge is spaced apart from the first center of the contour of the first edge by an eccentric distance.

[0006] A motor, comprising: The rotor assembly described above; and The stator assembly is arranged around the outer contour of the rotor assembly and includes a plurality of stator cores spliced ​​together. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present application will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments. Those skilled in the art will appreciate that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be used as a limitation on the scope of the present application. In addition, unless otherwise specified, the drawings are intended only to conceptually represent the composition or structure of the described objects and may contain exaggerated displays. The drawings are not necessarily drawn to scale.

[0008] Figure 1 It is a cross-sectional schematic diagram of an embodiment of the motor of the present application.

[0009] Figure 2 yes Figure 1 Schematic cross-section of some components of the rotor assembly.

[0010] Figure 3 yes Figure 1 Schematic cross-section of some components of the stator assembly.

[0011] Figure 4 yes Figure 2 Schematic diagram of the structure of the magnet.

[0012] Figure 5 This is a comparison chart of the cogging torque between the technical solution of the present application and the existing solution.

[0013] Figure 6 This is a comparison chart of the ripple torque between the technical solution of the present application and the existing solution.

[0014] Figure 7 This is a comparison diagram of the back electromotive force between the technical solution of the present application and the existing solution. DETAILED DESCRIPTION

[0015] The preferred embodiments of the present application will be described in detail below with reference to the accompanying drawings. It will be appreciated by those skilled in the art that these descriptions are only illustrative and exemplary and should not be construed as limiting the scope of protection of the present application.

[0016] First, it should be noted that the top, bottom, upward, downward, and other directional terms mentioned in this article are defined relative to the directions in the various drawings. These directions are relative concepts and will therefore vary depending on the position and state they are in. Therefore, these or other directional terms should not be understood as restrictive.

[0017] In addition, it should be pointed out that for any single technical feature described or implied in the embodiments of this document or any single technical feature shown or implied in the accompanying drawings, these technical features (or their equivalents) can be further combined to obtain other embodiments not directly mentioned in this document.

[0018] It should be noted that in different drawings, the same reference numerals denote the same or substantially the same components.

[0019] Figures 1 to 4 Detailed details of the motor 1 of the present application are shown. The motor 1 may include a rotor assembly 10 and a stator assembly 20. The motor 10 may have an axial direction AA. Figures 1 to 3 In the figure, the axial direction AA can be the vertical direction of the paper. The stator assembly 20 can be arranged along the axial direction AA, and the rotor assembly 10 can rotate with the axial direction AA as the rotation axis. The radial direction RR refers to the direction of the ray emitted from a point on the axial direction AA and in a plane perpendicular to the axial direction AA at this point. The circumferential direction CC refers to the direction of the circumference around the point in the above plane. Figures 1 to 4 , the axial direction AA is schematically indicated in the form of a double arrow and a black dot, and the radial direction RR and the circumferential direction CC are schematically indicated in the form of a double arrow.

[0020] The rotor assembly 10 may include a rotor body 100 and a plurality of magnetic steel stacks 200. The rotor body 100 may have a substantially circular cross-section and have a first radius R1 centered on a first center O1. In the illustrated embodiment, the first center O1 may also be a point where the axial direction AA intersects the paper surface. The outer surface of the rotor body 100 may include a plurality of groups of shoulders 101. The shoulders 101 cooperate with each other to fix the magnetic steel stacks 200. The number of magnetic steel stacks 200 may be eight or ten, and the magnetic steel stacks 200 may be composed of a series of magnetic steels and may be adhered to the outer surface of the rotor body 100 to form a rotor structure of a surface-mounted permanent magnet synchronous motor.

[0021] The magnetic steel stack 200 may be arranged along the axial direction AA and the circumferential direction CC. In the axial direction AA, the magnetic steel stack 200, the rotor body 100, and the stator assembly 20 may have substantially equal extension lengths. In the circumferential direction CC, a plurality of magnetic steel stacks 200 may be substantially evenly distributed on the outer surface of the rotor body 100. The magnetic steel stack 200 may be formed by a series of magnetic steel stacks.

[0022] like Figure 1 and Figure 2As shown in , the cross section of the magnetic steel stack 200 may include a first edge 201 and a second edge 202. The first edge 201 and the second edge 202 may have different centers and different radius profiles. The first edge 201 is arranged to face the outer surface of the rotor body 100, and the second edge 202 may be the outer surface away from the rotor body 100. The first edge 201 may have a first center O1 and a first radius R1. In the illustrated embodiment, the first center O1 of the contour of the first edge 201 and the center of the contour of the rotor body 100 may be substantially coincident or concentric. The first radius R1 of the circular contour of the first edge 201 may be substantially equal to the radius of the circular contour of the rotor body 100. Therefore, the first edge 201 may fit closely on the outer surface of the rotor body 100. In one embodiment, the first edge 201 may be adhered to the rotor body 100.

[0023] The second edge 202 may have a second center O2 and a second radius R2. In the illustrated embodiment, the second center O2 of the outline of the second edge 202 may be offset relative to the first center O1 of the outline of the first edge 201, or in other words, the second center O2 and the first center O1 are spaced apart. In the illustrated embodiment, the second center O2 may be disposed between the second edge 202 and the first center O1. Therefore, the second edge 202 may be eccentric relative to the first edge 201 and have a relatively protruding cross-sectional shape. The degree of eccentricity between the first center O1 and the second center O2 is represented by the eccentric distance O. Figure 2 In the figure, the minimum distance between the first center O1 and the second center O2 is the eccentric distance O.

[0024] In one embodiment, the eccentric distance O may be between 0.2 and 0.5 times the first radius R1. In one embodiment, the first radius R1 may be between 53 mm and 55 mm, for example, 53.2 mm. In one embodiment, the second radius R2 may be between 30 mm and 35 mm, for example, 31.2 mm. In one embodiment, the eccentric distance O may be between 20 mm and 25 mm, for example, 21.2 mm. The magnetic steel stack 200 may be an axisymmetric structure. For example, Figure 2 The vertical axis A1-A1 shown in the figure may be the symmetry axis of the magnetic steel stack 200. It is easy to understand that the first circle center O1 and the second circle center O2 are both located on the symmetry axis A1-A1 of the magnetic steel stack 200. Figure 2 As shown, the second circle center O2 may be closer to the magnetic steel stack 200 than the first circle center O1. In one embodiment, the first radius R1 may be greater than the second radius R2. Therefore, Figure 2 The curvature of the second profile 202 shown in FIG. 2 may be greater than the curvature of the first profile 201 .

[0025] like Figure 3 As shown, the plurality of magnetic steel stacks 200 may include a first group 201 and a second group 202. The first group 201 and the second group 202 may be arranged offset along the axial direction AA, and form a first offset angle θ between their axial angles when viewed in the circumferential direction CC. Figure 3 The arrangement of the first group 201 and the second group 202 as seen from the side of the rotor assembly 10 is shown, that is, Figure 3 The horizontal direction in corresponds to the axial direction AA of the rotor assembly 10, and Figure 3 The vertical direction in corresponds to the circumferential direction CC of the rotor assembly 10. The solid line BB represents a virtual straight line parallel to the axial direction AA on the outer peripheral contour of the rotor body 100, and the edge of the first group 201 is located on the solid line BB. The edge of the second group 202 is located on the dotted line. The edge of the first group 201 and the edge of the second group 202 are spaced apart in the circumferential direction CC. That is, when the Figure 2 and Figure 3 When observed from the perspective of , the edges of the first group 201 and the edges of the second group 202 are respectively located at different axial angles on the outer peripheral contour of the rotor body 100. Therefore, in the circumferential direction CC, the edges of the first group 201 and the edges of the second group 202 are located at different axial angles, and the angle between their axial angles is a first misalignment angle θ. In one embodiment, depending on the rotation direction of the rotor assembly 10, the first group 201 and the second group 202 may be staggered clockwise or counterclockwise. In one embodiment, the first misalignment angle θ may be between 3 degrees and 3.6 degrees.

[0026] The stator assembly 20 may be arranged around the outer contour of the rotor assembly 10. The stator assembly may include a plurality of stator cores 300 and a plurality of windings 310. The stator core 300 may be T-shaped and may include a pole shoe 301, a tooth portion 302, and a yoke portion 303. The yoke portions 303 of the stator core 300 may be connected together, and the number of the stator cores 300 may be ten, twelve, or fourteen. The inner portion of the pole shoe 301 may be combined into a substantially circular profile, for example having a third center O3 and a third radius R3. In the illustrated embodiment, the third center O3 may be substantially coincident with the first center O1. In one embodiment, the third radius R3 may be between 52 mm and 56 mm. In one embodiment, the third radius R3 may be approximately 54 mm.

[0027] An air gap 31 may be formed between the inner side of the pole piece 301 and the second edge 202 of the magnetic steel stack 200. In the radial direction RR, the air gap 31 may have a minimum size, also referred to as the air gap size σ. In one embodiment, the air gap size σ may be between 0.2 mm and 1.0 mm. In one embodiment, the air gap size σ may be approximately 0.8 mm.

[0028] In addition, the ends of adjacent pole shoes 301 are spaced apart in the circumferential direction CC, and the distance of the spacing is referred to as the stator slot width L. In one embodiment, the stator slot width L may be between 1.0 and 2.0 times the air gap size σ. In one embodiment, the stator slot width L may be approximately 1.17 mm.

[0029] The second radius R2 of the second edge 202 of the magnetic steel stack 200 may be defined in combination with the third radius R3 and the air gap size σ. In one embodiment, the second radius R2 may be substantially equal to the third radius R3 minus the eccentric distance O minus the air gap size σ.

[0030] The winding 310 can be a three-phase double-layer AC stacked winding. In one embodiment, the pitch of the winding 310 can be 1, the number of parallel paths can be 2, the number of windings can be 2, the number of turns of a single coil can be 85, and a star connection can be adopted. The winding 310 can adopt corona-resistant enameled wire and can be arranged in the slots between the stator core 300. In one embodiment, for the entire motor 10, it forms a 12-slot 10-pole matching form. In one embodiment, the motor 10 is a surface-mounted permanent magnet synchronous motor.

[0031] Figures 5 to 7 The following is a comparison of several performances between the motor of the technical solution of the present application and the motor of the prior art. Figures 5 to 7 In FIG. 1 , the horizontal axis T represents time, and the unit is milliseconds. The solid line 1 represents the sensing result of the technical solution of the present application, and the dotted line 2 represents the sensing result of the prior art. Figure 5 The CT on the vertical axis represents the cogging torque, and its unit is millinewton·meter (mN·m). Figure 6 The RT on the vertical axis represents the ripple torque (Ripple Torque), and its unit is Newton meter (N·m). Figure 7 The Back EMF on the vertical axis represents the back electromotive force (Back Electromotive Force), and its unit is volt (V). Figures 5 to 7As shown, the cogging torque, ripple torque and back electromotive force harmonic distortion rate of the motor of the technical solution of the present application are significantly improved. Therefore, the motor of the technical solution of the present application has achieved a significant improvement in noise performance. In one embodiment, the noise generated by the motor of the technical solution of the present application is reduced by more than 4% compared with the motor of the prior art.

[0032] The rotor assembly and the motor of the present application have the advantages of being simple and reliable, easy to implement, and convenient to use, etc. The technical solution of the present application can provide improved noise performance and significantly reduce the noise emitted by the motor during operation.

[0033] This specification discloses the present application with reference to the accompanying drawings, and also enables those skilled in the art to implement the present application, including making and using any device or system, selecting suitable materials, and using any combined method. The scope of the present application is defined by the technical solution for protection, and includes other examples that occur to those skilled in the art. As long as such other examples include structural elements that are not different from the literal language of the technical solution for protection, or such other examples include equivalent structural elements that are not substantially different from the literal language of the technical solution for protection, such other examples should be deemed to be within the scope of protection determined by the technical solution for protection of the present application.

Claims

1. A rotor assembly, characterized in that: include: A rotor body (100) extending along an axial direction (AA) and having a circular cross-section in the axial direction (AA), the circular cross-section having a first radius (R1); A plurality of magnetic steel stacks (200), wherein the magnetic steel stacks (200) are arranged on the outer surface of the rotor body (100); wherein, in the axial direction (AA), a cross section of the magnetic steel stack (200) comprises a first edge (201) and a second edge (202), the first edge (201) faces the rotor body (100) and has a first radius (R1), and the second edge (202) faces away from the rotor body (100) and has a second radius (R2); and The center of the contour of the first edge (201) is approximately concentric with the center of the outer contour of the rotor body (100), and the second center (O2) of the contour of the second edge (202) is spaced apart from the first center (O1) of the contour of the first edge (201) by an eccentric distance (O).

2. The rotor assembly according to claim 1, characterized in that: The second center (O2) of the contour of the second edge (202) is located between the first center (O1) of the contour of the first edge (201) and the second edge (202), and the eccentric distance (O) is between 0.2 and 0.5 times the first radius (R1).

3. The rotor assembly according to claim 1, characterized in that: The magnetic steel stacks (200) are evenly arranged on the outer surface of the rotor body (100), and the outer surface of the rotor body (100) includes a plurality of groups of shoulders (101) so as to accommodate the magnetic steel stacks (200) between the shoulders (101), wherein the number of the magnetic steel stacks (200) is eight or ten.

4. The rotor assembly according to claim 1, characterized in that: A plurality of magnetic steel stacks (200) include at least a first group (201) and a second group (202), wherein the first group (201) and the second group (202) are arranged in a staggered manner along an axial direction (AA), and in a circumferential direction (CC), a first staggered angle (θ) is formed between an axial angle of the second group (202) and an axial angle of the first group (201).

5. The rotor assembly according to claim 4, characterized in that: The first misalignment angle (θ) is between 3 degrees and 3.6 degrees.

6. A motor, characterized in that: include: A rotor assembly (10) according to any one of claims 1 to 5; as well as The stator assembly (20) is arranged around the outer contour of the rotor assembly (10) and comprises a plurality of stator cores (300) spliced ​​together.

7. The motor according to claim 6, characterized in that The stator core (300) comprises a pole shoe (301), an air gap (31) is formed between the pole shoe (301) and the second edge (202) of the magnetic steel stack (200), wherein the air gap (31) has an air gap size (σ) in a radial direction (RR).

8. The motor according to claim 7, characterized in that The ends of the pole shoes (301) of adjacent stator cores (300) are spaced apart in the circumferential direction (CC), and the spacing distance is the stator slot width (L); wherein the stator slot width (L) is between 1.0 times and 2.0 times the air gap size (σ).

9. The motor according to claim 7, characterized in that In the radial direction (RR), the inner contour of the pole shoe (301) is constructed to be substantially circular and has a third radius (R3), wherein the second radius (R2) is equal to the third radius (R3) minus the eccentric distance (O) minus the air gap size (σ).

10. The motor according to any one of claims 6 to 9, characterized in that: The number of the stator cores (300) is ten, twelve or fourteen.

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