Rotor structure and electric machine

Abstract

The utility model discloses a rotor structure and motor. The rotor structure includes rotor iron core, and the rotor iron core has multiple pairs of magnetic steel grooves arranged along the axial direction, and any pair of magnetic steel grooves is symmetrically arranged along the magnetic pole center line in the circumferential direction, the inner wall of the side, away from the magnetic pole center line, of the magnetic steel groove is an outer peripheral surface, and the outer peripheral surface is used for forming an outer magnetic bridge. The projection of the outer peripheral surface on the radial plane is a first projection, and the first projection is a curved profile. The rotor structure sets the inner wall of the side, away from the magnetic pole center line, of the magnetic steel groove as curved, thereby reducing the stress concentration degree of the outer magnetic bridge, so as to reduce the maximum stress borne by the outer magnetic bridge part at the same rotating speed, that is, to improve the rotating speed at the same borne maximum stress. The motor has all the beneficial effects of the rotor structure.

Description

Technical Field

[0001] This utility model relates to the field of rotor technology, and in particular to a rotor structure and motor. Background Technology

[0002] The market share of new energy vehicles continues to rise, and competition among vehicle brands is becoming increasingly fierce, placing extremely high demands on the cost of both the vehicle and its components. The power unit accounts for nearly half the cost of a pure electric vehicle, with the drive motor accounting for approximately 6-8% of the total vehicle cost. One of the main ways to reduce motor costs is through design optimization to reduce the amount of raw materials used. Based on motor characteristics, given a fixed output power, the higher the speed, the smaller the required motor radius. Therefore, developing high-speed motors can achieve cost reduction by increasing the design speed and miniaturizing the motor.

[0003] For the vast majority of permanent magnet synchronous motors on the market, the rotor design involves setting magnet slots on the rotor core, with the magnets placed in the slots. The thin connecting ribs formed around the magnet slots are magnetic isolation bridges, such as... Figure 1 As shown. The magnetic bridge is generally considered a weak point in the rotor, especially the area of ​​the external magnetic bridge. One of the challenges in high-speed motors is the strength of the magnetic bridge. At high speeds, the magnetic bridge continuously bears significant stress, which can lead to strain or even breakage.

[0004] Therefore, a new rotor structure and motor are urgently needed. Utility Model Content

[0005] The purpose of this utility model is to provide a rotor structure and a motor. The rotor structure reduces the stress concentration of the outer magnetic bridge by making the inner wall of the magnetic steel slot away from the magnetic pole center line curved, so as to reduce the maximum stress borne by the outer magnetic bridge part at the same speed, that is, to increase the speed when the maximum stress is the same.

[0006] This utility model discloses a rotor structure, which includes a rotor core;

[0007] The rotor core has multiple pairs of magnetic steel slots extending along the axial direction. Any pair of magnetic steel slots are symmetrically arranged in the circumferential direction along the magnetic pole center line. The inner wall of the magnetic steel slot on the side away from the magnetic pole center line is the outer circumferential surface, which is used to form an external magnetic bridge.

[0008] Wherein, the projection of the outer peripheral surface onto the radial plane is the first projection, and the first projection is a curved profile.

[0009] Furthermore, the outer peripheral surface protrudes towards the outer periphery of the rotor core, so that the first projection is an outwardly convex curved profile.

[0010] Furthermore, the first projection includes multiple sequentially connected surface segments, wherein at least two of the surface segments have different radii.

[0011] Furthermore, the center position of any of the surface segments is offset relative to the center position of the adjacent surface segments, so that the curvature centers of the multiple surface segments are not on the same straight line; by connecting the multiple surface segments in sequence, a wave-shaped first projection can be formed.

[0012] Furthermore, two adjacent curved surface segments are arranged tangent to each other.

[0013] Furthermore, the inner wall of the magnetic steel groove on the side near the center line of the magnetic pole is an inner circumferential surface, which is used to form an inner magnetic bridge. The projection of the inner circumferential surface onto the radial plane is a second projection, which is a curved profile.

[0014] Furthermore, the inner circumferential surface protrudes towards one side of the magnetic pole centerline, so that the second projection is an inwardly convex curved profile.

[0015] Furthermore, the inner circumferential surface and / or the outer circumferential surface have concave curved portions in the axial direction, such that the top and bottom ends of the curved portions are large-diameter ends in the axial direction, and the middle region of the curved portions is a small-diameter end.

[0016] Furthermore, the connection between the large-diameter end and the small-diameter end is a circular arc transition.

[0017] Furthermore, multiple pairs of the magnetic steel grooves are arranged in the same radial direction.

[0018] This utility model embodiment further discloses an electric motor, which includes the rotor structure described above.

[0019] The rotor structure and motor provided by this utility model have at least the following beneficial effects, including but not limited to:

[0020] 1) This rotor structure reduces the stress concentration of the outer magnetic bridge by making the inner wall of the magnetic slot away from the magnetic pole centerline curved, so as to reduce the maximum stress borne by the outer magnetic bridge part at the same speed, that is, to increase the speed when the maximum stress is the same.

[0021] 2) In this rotor structure, the outer periphery of the magnet slot is bent outward toward the outer periphery of the rotor core so that the first projection is convexly bent, thereby shortening the length of the outer magnetic bridge located outside the magnet slot in the radial direction, thereby reducing leakage flux and improving the concentration of the rotor magnetic circuit and the efficiency of magnetic energy utilization.

[0022] 3) In this rotor structure, the outer periphery of the magnet slot is composed of multiple curved segments. The centers of these segments are offset from each other, forming a continuous non-concentric curvature connection. This results in the outer periphery of the magnet slot exhibiting a wave-like shape resembling a spline curve, thus providing continuous curvature variation and smooth transition characteristics. This significantly reduces stress concentration at abrupt geometric changes and avoids the generation of local fatigue sources. Based on FKM infinite fatigue analysis, the fatigue utilization of the large magnet outer magnetic bridge is reduced by approximately 20%–21% after adopting the spline curve structure, significantly improving the structural reliability of this region under long-term alternating loads and extending the overall fatigue life of the rotor. Attached Figure Description

[0023] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0024] Figure 1 This is a schematic diagram of a rotor structure in related technologies;

[0025] Figure 2 A schematic diagram of the rotor structure provided for an embodiment of this utility model;

[0026] Figure 3 One of the schematic diagrams of the outer peripheral surface of the magnetic steel groove provided in the embodiment of this utility model in the radial plane;

[0027] Figure 4 A second schematic diagram of the outer peripheral surface of the magnetic steel groove in the radial plane provided for an embodiment of this utility model;

[0028] Figure 5 A cross-sectional view of the outer peripheral surface of the magnet groove provided in an embodiment of this utility model in the axial direction.

[0029] Icon: 100 - Rotor structure;

[0030] 11-Magnetic steel groove; 111-Outer peripheral surface; 1111-Curved section; 112-Inner peripheral surface; 113-Bent section;

[0031] 121 - External magnetic bridge; 122 - Internal magnetic bridge. Detailed Implementation

[0032] The following specific examples 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. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0033] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0034] Please refer to Figures 2-5 This application provides a rotor structure 100. The rotor structure 100 includes a rotor core with multiple pairs of magnetic steel slots 11 extending along the axial direction. Any pair of magnetic steel slots 11 are symmetrically arranged in the circumferential direction along the magnetic pole centerline. The inner wall of the magnetic steel slot 11 on the side away from the magnetic pole centerline is the outer circumferential surface 111, which is used to form an outer magnetic bridge 121. The projection of the outer circumferential surface 111 onto the radial plane is a first projection, which is a curved profile.

[0035] It should be noted that the magnetic steel groove 11 in this embodiment is used to accommodate magnetic steel (such as permanent magnet blocks), and the magnetic pole center line refers to the symmetrical center line of each pair of magnetic steel grooves 11 in the circumferential direction, that is, the magnetic flux density symmetry axis corresponding to the magnetic pole.

[0036] It should also be noted that in this embodiment, the axial direction refers to the direction of the rotor core's axis, and the circumferential direction refers to the circumferential direction of the rotor core.

[0037] It is worth noting that the rotor structure 100 reduces the stress concentration of the outer magnetic bridge 121 by setting the inner wall of the magnetic steel groove 11 away from the magnetic pole center line as a curved profile, i.e., a curved shape. This reduces the maximum stress borne by the outer magnetic bridge 121 at the same rotational speed, thereby increasing the rotational speed when the maximum stress is the same.

[0038] Please refer to this again. Figure 3 In one embodiment of this invention, the outer peripheral surface 111 protrudes outward toward the outer periphery of the rotor core, so that the first projection is an outwardly protruding curved profile.

[0039] It is worth noting that the first projection is an outwardly convex curved profile, that is, it is convexly curved. This means that the first projection as a whole presents a convex curve, but it may have local small areas that are concave (e.g. Figure 4 (As shown), for the transition of lines. This structural design can shorten the radial length of the outer magnetic bridge 121 located outside the magnetic slot 11, thereby reducing leakage flux and improving the concentration of the rotor magnetic circuit and the efficiency of magnetic energy utilization.

[0040] Optionally, the first projection includes multiple sequentially connected surface segments 1111, wherein at least two surface segments 1111 have different radii.

[0041] Specifically, the existence of at least two curved surface segments 1111 with different radii allows the entire outer perimeter profile to exhibit a composite curved structure with non-uniform radius and curvature. This curvature variation enables the geometry of the outer perimeter surface 111 of the magnet slot 11 to better align with the distribution trend of the main magnetic flux path, facilitating flux concentration in key areas and reducing flux leakage at the outer magnetic bridge 121, thereby improving magnetic circuit efficiency. Simultaneously, the transition between curvature segments with different radii is smoother than structures with constant or abrupt curvature, reducing stress concentration at corners or curvature abrupt changes, thus enhancing the fatigue resistance of the magnetic bridge region.

[0042] Please refer to this again. Figure 4 In another embodiment of this invention, the center position of any curved surface segment 1111 is offset relative to the center position of the adjacent curved surface segment 1111, so that the curvature centers of multiple curved surface segments 1111 are not on the same straight line; by connecting multiple curved surface segments 1111 in sequence, a wave-shaped first projection can be formed.

[0043] It is worth noting that in this rotor structure 100, the outer peripheral surface 111 of the magnet slot 11 is composed of multiple curved surface segments 1111. The centers of each curved surface segment 1111 are offset from each other, forming a continuous non-concentric curvature connection. This makes the outer peripheral boundary of the magnet slot 11 exhibit an approximately spline curve-like wave shape, thus possessing continuous curvature changes and smooth transition characteristics. This significantly reduces stress concentration at geometric abrupt changes in the structure and avoids the generation of local fatigue sources. Based on FKM infinite fatigue analysis, it is shown that after adopting the spline curve structure, the fatigue utilization of the large magnet outer magnetic bridge 121 is reduced by approximately 20% to 21%, significantly improving the structural reliability of this region under long-term alternating loads and extending the overall fatigue life of the rotor. Depending on the specific implementation environment, the wave-like first projection can be a cubic spline curve or a Bézier curve to ensure surface continuity and smooth transition of the magnetic flux path.

[0044] Optionally, two adjacent surface segments 1111 are set to be tangent.

[0045] Specifically, the two tangential curved surface segments 1111 can form a smooth and continuous outer periphery, which helps to improve the uniformity of magnetic field distribution, reduce stress concentration, and facilitate processing and manufacturing.

[0046] In this embodiment, the inner wall of the magnetic steel groove 11 near the center line of the magnetic pole is an inner circumferential surface 112. The inner circumferential surface 112 is used to form an inner magnetic bridge 122. The projection of the inner circumferential surface 112 onto the radial plane is a second projection, which is a curved profile.

[0047] It is worth noting that the curved inner circumferential surface 112 can reduce the stress concentration of the inner magnetic bridge 122, thereby reducing the maximum stress borne by the inner magnetic bridge 122 at the same rotational speed, which in turn increases the rotational speed when the maximum stress is the same.

[0048] Optionally, the inner circumferential surface 112 is convex toward one side of the magnetic pole centerline, so that the second projection is an inwardly convex curved profile.

[0049] Specifically, the second projection is an inwardly convex curved profile, that is, it is convexly curved inward, which can shorten the width of the inner magnetic bridge 122, thereby reducing the leakage flux.

[0050] Please refer to this again. Figure 5 The inner circumferential surface 112 and / or the outer circumferential surface 111 have a concave curved portion 113 in the axial direction, such that the top and bottom ends of the curved portion 113 are large-diameter ends in the axial direction, and the middle region of the curved portion 113 is a small-diameter end.

[0051] It is worth noting that the radial dimensions of the top and bottom ends of the bend 113 are relatively large, which allows for a smaller spacing between the magnetic bridges at the top (near the air gap side), effectively compressing the leakage flux path and reducing leakage flux loss. The middle section of the bend 113 has a small-diameter structure, which allows for a relatively large spacing between the magnetic bridges in the middle, thus providing sufficient mechanical cross-sectional area and enhancing the overall strength of the magnetic bridge region, ensuring the structural stability of the rotor under high speed and alternating loads. In addition, the bend 113 has a circular arc or curved surface transition, which can mitigate stress concentration caused by cross-sectional changes, improve fatigue life, and reduce the risk of crack initiation.

[0052] In this embodiment, the connection between the large-diameter end and the small-diameter end is rounded. It can be understood that the rounded transition between the large-diameter end and the small-diameter end can further reduce stress concentration.

[0053] In this embodiment, multiple pairs of magnetic slots 11 are arranged in the same radial direction. It is understood that, as... Figure 2As shown, two pairs of magnet slots 11 can be arranged in the same radial direction to increase the number of magnets per pole, thereby increasing the effective area of ​​the magnetic poles, improving the magnetic flux coupling efficiency between the stator and rotor, and thus enhancing the output torque. Depending on the specific implementation environment, three or four pairs of magnet slots 11 can also be arranged, etc.

[0054] This utility model embodiment further discloses an electric motor, which includes the rotor structure 100 described above and has all its beneficial effects.

[0055] 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.

[0056] Throughout this description, numerous specific details, such as examples of components and / or methods, are provided to provide a complete understanding of embodiments of the present invention. However, those skilled in the art will recognize that embodiments of the present invention may be practiced without one or more of these specific details or by other devices, systems, components, methods, parts, materials, components, etc. In other instances, well-known structures, materials, or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the present invention.

[0057] Throughout this specification, references to "an embodiment," "an embodiment," or "a specific embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention, but not necessarily in all embodiments. Therefore, the various representations of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout the specification do not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic of any specific embodiment of the present invention can be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the present invention shown herein may be based on the teachings herein and will be considered part of the spirit and scope of the present invention.

[0058] It should also be understood that one or more of the elements shown in the figures may be implemented in a more separate or more integrated manner, or may even be removed because they are inoperable in certain circumstances or provided because they may be useful for a particular application.

[0059] Furthermore, unless otherwise expressly stated, any arrows in the accompanying drawings should be considered illustrative only and not limiting. Additionally, unless otherwise stated, the term "or" as used herein is generally intended to mean "and / or". Where a term is anticipated to provide a separation or combination capability that is unclear, a combination of components or steps will also be considered as indicated.

[0060] As used herein and throughout the claims below, unless otherwise specified, “a” and “the” include the plural references. Similarly, as used herein and throughout the claims below, unless otherwise specified, “in” means “in” and “on”.

[0061] The above description of the embodiments shown in this utility model (including the content in the abstract of the specification) is not intended to be an exhaustive enumeration or to limit the utility model to the precise forms disclosed herein. Although specific embodiments and examples of the utility model have been described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the utility model, as will be recognized and understood by those skilled in the art. As indicated, these modifications can be made to the utility model in accordance with the above description of the embodiments of the utility model, and such modifications will be within the spirit and scope of the utility model.

[0062] This document has generally described the systems and methods in detail to aid in understanding the present invention. Furthermore, various specific details have been set forth to provide a general understanding of embodiments of the present invention. However, those skilled in the art will recognize that embodiments of the present invention can be practiced without one or more specific details, or using other devices, systems, accessories, methods, components, materials, parts, etc. In other instances, well-known structures, materials, and / or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the present invention.

Claims

1. A rotor structure, characterized in that, Including the rotor core; The rotor core has multiple pairs of magnetic steel slots extending along the axial direction. Any pair of magnetic steel slots are symmetrically arranged in the circumferential direction along the magnetic pole center line. The inner wall of the magnetic steel slot on the side away from the magnetic pole center line is the outer circumferential surface, which is used to form an external magnetic bridge. Wherein, the projection of the outer peripheral surface onto the radial plane is the first projection, and the first projection is a curved profile.

2. The rotor structure according to claim 1, characterized in that, The outer peripheral surface protrudes towards the outer periphery of the rotor core, so that the first projection is an outwardly convex curved profile.

3. The rotor structure according to claim 1, characterized in that, The first projection includes multiple sequentially connected curved surface segments, wherein at least two of the curved surface segments have different radii.

4. The rotor structure according to claim 3, characterized in that, The center position of any of the surface segments is offset relative to the center position of the adjacent surface segments, so that the curvature centers of the multiple surface segments are not on the same straight line; By sequentially connecting multiple of the aforementioned curved surface segments, a first projection in a wave-like shape can be formed.

5. The rotor structure according to claim 3, characterized in that, The two adjacent curved surface segments are set to be tangent.

6. The rotor structure according to claim 1, characterized in that, The inner wall of the magnetic steel groove near the center line of the magnetic pole is an inner circumferential surface, which is used to form an inner magnetic bridge. The projection of the inner circumferential surface onto the radial plane is a second projection, which is a curved profile.

7. The rotor structure according to claim 6, characterized in that, The inner circumferential surface protrudes towards one side of the magnetic pole centerline, so that the second projection is an inwardly convex curved profile.

8. The rotor structure according to claim 6, characterized in that, The inner circumferential surface and / or the outer circumferential surface have a concave curved portion in the axial direction, such that the top and bottom ends of the curved portion are large-diameter ends in the axial direction, and the middle region of the curved portion is a small-diameter end.

9. The rotor structure according to claim 8, characterized in that, The connection between the large-diameter end and the small-diameter end is a rounded transition.

10. The rotor structure according to claim 1, characterized in that, Multiple pairs of the magnetic steel grooves are arranged in the same radial direction.

11. An electric motor, characterized in that, Includes the rotor structure as described in any one of claims 1-10.

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