Rotor lamination and electric machine

Abstract

The application provides a rotor lamination, which is circumferentially divided into a plurality of identical sectors, and each sector comprises a base body and a first magnetic steel slot, a bottom magnetic steel slot and a weight-reducing slot distributed on the base body, the bottom magnetic steel slot is close to a center line of the rotor lamination relative to the first magnetic steel slot, and the weight-reducing slot is located between the first magnetic steel slot and the bottom magnetic steel slot. According to the scheme, the rotor lamination inserts magnetic steels from the first magnetic steel slot and the bottom magnetic steel slot to work. The weight-reducing slot between the first magnetic steel slot and the bottom magnetic steel slot plays a role in reducing the stress of the magnetic bridge, improves the magnetic flux distribution of the rotor and reduces the torque ripple. After the magnetic steel slot is added, the mechanical stress distribution on the rotor lamination under high speed is optimized while the electromagnetic performance is ensured.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and more specifically, to a rotor lamination and a motor. Background Technology

[0002] Permanent magnet assisted synchronous reluctance motors have high torque and power density, large salient pole ratio, excellent speed regulation performance, high efficiency, and use less permanent magnet material, resulting in low cost. In recent years, they have been widely used in various fields, including electric vehicles.

[0003] With the rapid development of new energy vehicles, automotive permanent magnet motors are gradually evolving towards higher power density and higher speeds. Motors can be categorized by operating speed into high-speed motors and low-speed motors, with high-speed motors typically referring to those exceeding 10,000 rpm. These motors place high demands on rotor laminations. Traditional methods of increasing rotor strength enhance the structural strength of the rotor laminations, but improving material properties significantly increases costs. Increasing the width of the magnetic bridge inevitably reduces motor performance, making it difficult to achieve high power density. High power density and high speed can be considered two contradictory requirements, which existing design methods struggle to simultaneously meet. How to optimize the mechanical stress distribution on the rotor laminations at high speeds while maintaining electromagnetic performance under existing lamination material properties, thereby achieving high-speed rotor operation, is a pressing problem to be solved. Summary of the Invention

[0004] This invention provides a rotor lamination and a motor to solve the problem of being unable to optimize the mechanical stress distribution on the rotor lamination at high speeds while ensuring electromagnetic performance.

[0005] To address the aforementioned problems, according to one aspect of the present invention, a rotor lamination is provided, wherein the rotor lamination is circumferentially divided into a plurality of identical sector portions, each sector portion including a base and a first magnet slot, a bottom magnet slot, and a weight reduction slot distributed on the base, wherein the bottom magnet slot is closer to the centerline of the rotor lamination relative to the first magnet slot, and the weight reduction slot is located between the first magnet slot and the bottom magnet slot.

[0006] Furthermore, the sector-shaped portion has two first magnetic slots, which are symmetrically arranged with respect to the symmetrical face of the sector-shaped portion. The solid structure of the narrowest region between the two first magnetic slots is a middle magnetic bridge. The symmetrical face divides the bottom magnetic slot into two symmetrical parts. The sector-shaped portion has two weight-reducing slots, which are symmetrically arranged with respect to the symmetrical face.

[0007] Furthermore, the weight-reducing grooves are rectangular in structure, and there is an angle between the extending directions of the two weight-reducing grooves.

[0008] Furthermore, the line connecting the two corners of the two weight-reducing grooves that face each other and are close to the center line is the first connecting line, and the minimum distance between the first connecting line and the first magnet groove is L1. The line connecting the two corners of the two weight-reducing grooves that face each other and are far from the center line is the second connecting line, and the minimum distance between the second connecting line and the bottom magnet groove is L2, where L2 = (1.8~2.2)L1.

[0009] Furthermore, the sector-shaped portion also includes a second magnetic steel groove disposed on the base. The side of the second magnetic steel groove near the sector-shaped portion is opposite to the side of the first magnetic steel groove. The solid structure between the end of the second magnetic steel groove and the end of the bottom magnetic steel groove is a bottom magnetic isolation bridge. The angle between the extension direction of the bottom magnetic isolation bridge and the symmetry plane of the sector-shaped portion is b, and the angle between the extension direction of the weight reduction groove and the symmetry plane is a, where a = (0.75~0.85)b.

[0010] Furthermore, the sector-shaped portion also includes air gap side weight reduction holes, which are located within the solid structure on one side of the first magnet slot.

[0011] Furthermore, the air gap side weight reduction hole is elliptical, and the air gap side weight reduction hole is divided into two symmetrical parts by the symmetry plane of the fan-shaped part. The rotor lamination has a shaft hole in the middle, and the difference between the radius of the rotor lamination and the radius of the shaft hole is H1. The distance between the center line of the air gap side weight reduction hole and the outer peripheral surface of the rotor lamination is H2, where H2 = (0.09~0.1)H1.

[0012] Furthermore, the sector-shaped portion also includes a paraxial weight reduction hole disposed on the substrate, which is located between the centerline and the bottom magnet groove.

[0013] Furthermore, the paraxial weight reduction hole is formed by a first arc, a second arc, and a third arc. The first arc is closer to the bottom magnet groove than the second arc, and the third arc is closer to the side of the fan-shaped part than the first and second arcs.

[0014] Furthermore, the radius of the first arc is r1, the radius of the second arc is r2, and the radius of the third arc is r3, where r1 = (1.3~1.35)r2 and r3 = (0.35~0.4)r2.

[0015] Furthermore, the minimum distance between the midpoint of the first arc and the bottom magnetic groove is d1, the minimum distance between the midpoint of the second arc and the bottom magnetic groove is d2, the distance between the midpoint of the third arc and the symmetry plane of the sector is d3, and the distance between the midpoint of the third arc and the side of the sector is d4, where d1 = (0.75~0.8)d2 and d3 = (8.5~9.5)d4.

[0016] Furthermore, there are two paraxial weight reduction holes, which are symmetrically arranged with respect to the symmetrical face of the sector.

[0017] According to another aspect of the present invention, an electric motor is provided, the motor comprising the rotor laminations described above.

[0018] The present invention provides a rotor lamination, which is circumferentially divided into multiple identical sector-shaped portions. Each sector includes a base and a first magnet slot, a bottom magnet slot, and a weight-reducing slot distributed on the base. The bottom magnet slot is closer to the centerline of the rotor lamination than the first magnet slot, and the weight-reducing slot is located between the first magnet slot and the bottom magnet slot. Using this solution, the rotor lamination inserts magnets through the first magnet slot and the bottom magnet slot during practical application. Adding a weight-reducing slot between the first magnet slot and the bottom magnet slot reduces magnetic bridge stress and improves the distribution of rotor magnetic lines of force, reducing torque pulsation. This solution, by adding a weight-reducing slot, optimizes the mechanical stress distribution on the rotor lamination at high speeds while maintaining electromagnetic performance. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0020] Figure 1 A schematic diagram of the rotor lamination structure provided in an embodiment of the present invention is shown;

[0021] Figure 2 It shows Figure 1 Schematic diagram of the structure of the central sector section;

[0022] Figure 3 It shows Figure 2 A schematic diagram showing the dimensions of the central sector section;

[0023] Figure 4 It shows Figure 2 Detailed view of the weight reduction hole on the mid-to-near axis.

[0024] The above figures include the following reference numerals:

[0025] 100, sector-shaped part; 200, shaft hole; 300, outer peripheral surface;

[0026] 11. Matrix; 12. Plane of symmetry;

[0027] 21. First magnetic steel channel; 22. Middle magnetic bridge;

[0028] 30. Bottom magnetic steel channel;

[0029] 41. Weight reduction groove; 42. First connecting line; 43. Second connecting line;

[0030] 51. Second magnetic steel groove; 52. Bottom magnetic bridge;

[0031] 60. Air gap side weight reduction hole;

[0032] 70. Off-axis weight reduction hole; 71. First arc; 72. Second arc; 73. Third arc. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] like Figures 1 to 4 As shown, an embodiment of the present invention provides a rotor lamination, which is divided into a plurality of identical sector-shaped portions 100 in the circumferential direction. Each sector-shaped portion 100 includes a base 11 and a first magnet groove 21, a bottom magnet groove 30 and a weight reduction groove 41 distributed on the base 11. The bottom magnet groove 30 is closer to the center line of the rotor lamination than the first magnet groove 21, and the weight reduction groove 41 is located between the first magnet groove 21 and the bottom magnet groove 30.

[0035] In this design, the rotor laminations insert magnets into the first magnet slot 21 and the bottom magnet slot 30 during practical applications. A weight-reducing slot 41 is added between the first magnet slot 21 and the bottom magnet slot 30, which reduces the stress on the magnetic bridge while improving the distribution of the rotor's magnetic flux lines and reducing torque pulsation. By adding the weight-reducing slot 41, this design optimizes the distribution of mechanical stress on the rotor laminations at high speeds while maintaining electromagnetic performance.

[0036] like Figure 2 As shown, the sector 100 has two first magnetic grooves 21, which are symmetrically arranged with respect to the symmetry plane 12 of the sector 100. The solid structure of the narrowest region between the two first magnetic grooves 21 is a middle magnetic bridge 22. The symmetry plane 12 divides the bottom magnetic groove 30 into two symmetrical parts. The sector 100 has two weight-reducing grooves 41, which are symmetrically arranged with respect to the symmetry plane 12.

[0037] The two first magnet slots 21, the bottom magnet slot 30, and the two weight-reducing slots 41 are all symmetrically arranged with respect to the symmetry plane 12 of the sector portion 100. This arrangement ensures that the rotor laminations remain symmetrical after the magnets are inserted during actual application, resulting in uniform force and magnetic field distribution. The intermediate magnetic bridge 22 serves to limit magnetic leakage. In a specific embodiment of the invention, the included angle between the extending directions of the two first magnet slots 21 is an acute angle.

[0038] like Figure 1 As shown, the weight-reducing groove 41 is specifically a rectangular structure, and there is an included angle between the extending directions of the two weight-reducing grooves 41. Of course, the weight-reducing groove 41 can also be triangular, circular, or other shapes.

[0039] like Figure 2 As shown, the line connecting the two corners of the two weight-reducing grooves 41 that face each other and are close to the center line is the first connecting line 42. The minimum distance between the first connecting line 42 and the first magnet groove 21 is L1. The line connecting the two corners of the two weight-reducing grooves 41 that face each other and are far from the center line is the second connecting line 43. The minimum distance between the second connecting line 43 and the bottom magnet groove 30 is L2. Wherein, L2 = (1.8~2.2)L1.

[0040] This arrangement allows the weight-reducing groove 41 to be close to the middle magnetic bridge 22, which helps to disperse the stress on the middle magnetic bridge 22, while preventing the weight-reducing groove 41 from getting close to the bottom magnetic bridge 52 and causing stress concentration near the bottom magnetic bridge 52.

[0041] In one specific embodiment, a simulation comparison was conducted between rotor laminations with and without weight reduction grooves 41 under the same high-speed operating conditions. The maximum stress of the rotor lamination with weight reduction grooves 41 was 337.7 MPa, while the maximum stress of the rotor lamination without weight reduction grooves 41 was 375.66 MPa. This fully verifies that the weight reduction grooves 41 in this solution achieve the effect of reducing stress.

[0042] like Figure 2 As shown, the sector 100 also includes a second magnetic groove 51 disposed on the base 11. The second magnetic groove 51 is located near the side of the sector 100 relative to the first magnetic groove 21. The solid structure between the end of the second magnetic groove 51 and the end of the bottom magnetic groove 30 is a bottom magnetic bridge 52. The angle between the extension direction of the bottom magnetic bridge 52 and the symmetry plane 12 of the sector 100 is b, and the angle between the extension direction of the weight reduction groove 41 and the symmetry plane 12 is a, where a = (0.75~0.85)b.

[0043] This configuration allows the weight-reducing slot 41 to reduce the stress on the bottom magnetic bridge 52 while improving the distribution of rotor magnetic lines of force and reducing torque pulsation. The bottom magnetic slot 30 is an isosceles trapezoid, and there are two second magnetic slots 51, which are symmetrically arranged with respect to the plane of symmetry 12. In a specific embodiment of the invention, the stress on the rotor laminations is significantly reduced after adding the weight-reducing slot 41.

[0044] like Figure 1As shown, the sector 100 also includes an air gap-side weight reduction hole 60, which is located within the solid structure on one side of the first magnet slot 21. This configuration allows the air gap-side weight reduction hole 60 to reduce the weight of the rotor laminations, improve the distribution of rotor magnetic lines of force, reduce rotor stress, increase rotor strength, reduce torque pulsation, and ensure power density while reducing cogging torque.

[0045] like Figure 3 As shown, the air gap side weight reduction hole 60 is elliptical. Of course, the air gap side weight reduction hole 60 can also be rectangular, circular, or other shapes. The air gap side weight reduction hole 60 is divided into two symmetrical parts by the symmetry plane 12 of the sector 100. The rotor lamination has a shaft hole 200 in the middle. The difference between the radius of the rotor lamination and the radius of the shaft hole 200 is H1. The distance between the center line of the air gap side weight reduction hole 60 and the outer peripheral surface 300 of the rotor lamination is H2, where H2 = (0.09~0.1)H1.

[0046] This arrangement, placing the air gap-side weight reduction hole 60 close to the air gap side (i.e., the outer circumferential surface 300 side of the rotor lamination), can reduce cogging torque while ensuring rotor output torque and power, thereby minimizing rotor stress and optimizing stress distribution. Dividing the air gap-side weight reduction hole 60 into two symmetrical parts along the symmetry plane 12 of the sector 100 makes the rotor laminations symmetrical overall and the stress distribution more uniform.

[0047] In one specific embodiment, a rotor lamination with air gap side weight reduction holes 60 and a rotor lamination without air gap side weight reduction holes 60 (both containing weight reduction grooves 41) were simulated and compared under the same high-speed operating conditions. The maximum stress of the rotor lamination with air gap side weight reduction holes 60 was 291.39 MPa, while the maximum stress of the rotor lamination without air gap side weight reduction holes 60 was 337.7 MPa. This fully verifies that the air gap side weight reduction holes 60 in this solution achieve the effect of reducing stress.

[0048] like Figure 3 As shown, the sector 100 also includes a near-axial weight reduction hole 70 disposed on the base 11, which is located between the centerline and the bottom magnet slot 30. The near-axial weight reduction hole 70 can reduce the weight of the rotor laminations, improve the distribution of rotor magnetic lines of force, and reduce torque pulsation.

[0049] like Figure 4 As shown, the near-axial weight reduction hole 70 is formed by a first arc 71, a second arc 72 and a third arc 73. The first arc 71 is closer to the bottom magnet groove 30 relative to the second arc 72, and the third arc 73 is closer to the side of the fan-shaped part 100 relative to the first arc 71 and the second arc 72.

[0050] like Figure 4As shown, the radius of the first arc 71 is r1, the radius of the second arc 72 is r2, and the radius of the third arc 73 is r3, where r1 = (1.3~1.35)r2 and r3 = (0.35~0.4)r2.

[0051] This design increases the curvature of the near-axial weight reduction hole 70 on the side closest to the bottom magnetic bridge 52, preventing stress concentration on that side and improving the stress distribution of the bottom magnetic bridge 52. In a specific embodiment of the invention, the stress on the rotor lamination is significantly reduced after adding the near-axial weight reduction hole 70.

[0052] like Figure 4 As shown, the minimum distance between the midpoint of the first arc 71 and the bottom magnetic groove 30 is d1, the minimum distance between the midpoint of the second arc 72 and the bottom magnetic groove 30 is d2, the distance between the midpoint of the third arc 73 and the symmetry plane 12 of the sector 100 is d3, and the distance between the midpoint of the third arc 73 and the side of the sector 100 is d4, where d1 = (0.75~0.8)d2 and d3 = (8.5~9.5)d4.

[0053] This setting determines the position of the near-axis weight reduction hole 70, which makes the near-axis weight reduction hole 70 more effective in reducing rotor stress.

[0054] like Figure 4 As shown, there are two near-axial weight reduction holes 70, which are symmetrically arranged with respect to the symmetry plane 12 of the sector portion 100. This arrangement results in a symmetrical rotor lamination structure, which can reduce stress and improve service life during practical applications.

[0055] In one specific embodiment, rotor laminations with near-axis weight reduction holes 70 and rotor laminations without near-axis weight reduction holes 70 (both containing weight reduction grooves 41 and air gap side weight reduction holes 60) were compared in simulation under the same high-speed operating conditions. The maximum stress of the rotor lamination with near-axis weight reduction holes 70 was 248.14 MPa, while the maximum stress of the rotor lamination without near-axis weight reduction holes 70 was 291.39 MPa. This fully verifies that the near-axis weight reduction holes 70 in this solution achieve the effect of reducing stress.

[0056] Furthermore, the above specific embodiments also demonstrate that, in this solution, the rotor laminations with the weight reduction groove 41, the air gap side weight reduction hole 60, and the near-shaft side weight reduction hole 70 simultaneously have a better stress reduction effect than those with only one or two of them.

[0057] According to another aspect of the present invention, an electric motor is provided, the motor comprising the rotor laminations described above.

[0058] This invention addresses the problems of insufficient rotor lamination strength, large torque pulsation, high cogging torque, and low power in motors at high speeds. It adds weight-reducing slots below the central magnetic bridge to reduce stress on the bridge and improve the rotor's magnetic flux distribution, thus reducing torque pulsation. Weight-reducing holes are added to the air gap side of the rotor to increase rotor strength while maintaining power density. Weight-reducing holes are also added to the near-shaft side to optimize stress distribution and reduce rotor stress at the bottom magnetic bridge. In one specific embodiment, the maximum rotor stress is reduced from 375 MPa to 248 MPa while maintaining electromagnetic performance.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rotor lamination, characterized in that, The rotor lamination is divided into multiple identical sector sections (100) in the circumferential direction. Each sector section (100) includes a base (11) and a first magnet groove (21), a bottom magnet groove (30), and a weight reduction groove (41) distributed on the base (11). The bottom magnet groove (30) is closer to the center line of the rotor lamination than the first magnet groove (21), and the weight reduction groove (41) is located between the first magnet groove (21) and the bottom magnet groove (30). The sector (100) further includes a second magnetic groove (51) disposed on the base (11). The second magnetic groove (51) is located near the side of the sector (100) relative to the first magnetic groove (21). The solid structure between the end of the second magnetic groove (51) and the end of the bottom magnetic groove (30) is a bottom magnetic bridge (52). The angle between the extension direction of the bottom magnetic bridge (52) and the symmetry plane (12) of the sector (100) is b, and the angle between the extension direction of the weight-reducing groove (41) and the symmetry plane (12) is a, where a = (0.75~0.85)b.

2. The rotor lamination according to claim 1, characterized in that, The sector (100) has two first magnet slots (21), which are symmetrically arranged with respect to the symmetry plane (12) of the sector (100). The solid structure of the narrowest area between the two first magnet slots (21) is a middle magnetic bridge (22). The symmetry plane (12) divides the bottom magnet slot (30) into two symmetrical parts. The sector (100) has two weight-reducing slots (41), which are symmetrically arranged with respect to the symmetry plane (12).

3. The rotor lamination according to claim 2, characterized in that, The weight-reducing groove (41) has a rectangular structure, and there is an angle between the extending directions of the two weight-reducing grooves (41).

4. The rotor lamination according to claim 3, characterized in that, The line connecting the two corners of the two weight-reducing grooves (41) that face each other and are close to the center line is the first connecting line (42). The minimum distance between the first connecting line (42) and the first magnet groove (21) is L1. The line connecting the two corners of the two weight-reducing grooves (41) that face each other and are far from the center line is the second connecting line (43). The minimum distance between the second connecting line (43) and the bottom magnet groove (30) is L2. Wherein, L2 = (1.8~2.2)L1.

5. The rotor lamination according to claim 1, characterized in that, The sector (100) also includes an air gap side weight reduction hole (60), which is located in the solid structure on one side of the first magnet groove (21).

6. The rotor lamination according to claim 5, characterized in that, The air gap side weight reduction hole (60) is elliptical. The air gap side weight reduction hole (60) is divided into two symmetrical parts by the symmetry plane (12) of the fan-shaped part (100). The rotor lamination has a shaft hole (200) in the middle. The difference between the radius of the rotor lamination and the radius of the shaft hole (200) is H1. The distance between the center line of the air gap side weight reduction hole (60) and the outer peripheral surface (300) of the rotor lamination is H2, where H2 = (0.09~0.1)H1.

7. The rotor lamination according to claim 1, characterized in that, The sector (100) also includes a paraxial weight reduction hole (70) disposed on the base (11), the paraxial weight reduction hole (70) being located between the center line and the bottom magnet groove (30).

8. The rotor lamination according to claim 7, characterized in that, The near-axial weight reduction hole (70) is formed by a first arc (71), a second arc (72) and a third arc (73), the first arc (71) being closer to the bottom magnet groove (30) relative to the second arc (72), and the third arc (73) being closer to the side of the sector (100) relative to the first arc (71) and the second arc (72).

9. The rotor lamination according to claim 8, characterized in that, The radius of the first arc (71) is r1, the radius of the second arc (72) is r2, and the radius of the third arc (73) is r3, where r1 = (1.3~1.35)r2 and r3 = (0.35~0.4)r2.

10. The rotor lamination according to claim 8, characterized in that, The minimum distance between the midpoint of the first arc (71) and the bottom magnet groove (30) is d1, the minimum distance between the midpoint of the second arc (72) and the bottom magnet groove (30) is d2, the distance between the midpoint of the third arc (73) and the symmetry plane (12) of the sector (100) is d3, and the distance between the midpoint of the third arc (73) and the side of the sector (100) is d4, where d1 = (0.75~0.8)d2 and d3 = (8.5~9.5)d4.

11. The rotor lamination according to claim 7, characterized in that, There are two paraxial weight reduction holes (70), and the two paraxial weight reduction holes (70) are symmetrically arranged with respect to the symmetry plane (12) of the sector (100).

12. An electric motor, characterized in that, The motor includes rotor laminations as described in any one of claims 1 to 11.

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