Improved rotor and distributed winding stator / rotor structure for permanent magnet motors

Abstract

This utility model discloses an improved rotor for a permanent magnet motor, comprising a rotor core with slots for magnets and magnets inserted into the rotor core. Each slot is composed of V-shaped mounting slots that correspond one-to-one with the magnets. A magnetic barrier cavity, wedge-shaped, is connected to the outer end of each mounting slot. The inner wall areas of the wedge-shaped cavity are unequal. A distributed rotor-stator structure includes a stator and the aforementioned rotor. The stator includes a stator core with an even number of stator teeth arranged thereon. Stator slots are formed between adjacent stator teeth. Each stator tooth includes a tooth body and a tooth shoe. The surface of each tooth shoe facing the inner hole of the stator core is a concave arc surface, and the curvature of each concave arc surface is greater than the curvature of the inner hole of the stator core. This rotor improves the sinusoidal nature of the back electromotive force, reduces harmonic components, and helps reduce vibration and noise in the permanent magnet motor. The design of each tooth crown in the stator core as a concave arc reduces cogging torque and results in low output torque fluctuation.

Description

Technical Field

[0001] This utility model belongs to the field of permanent magnet motor technology, specifically relating to an improved rotor and distributed winding stator-rotor structure for permanent magnet motors. Background Technology

[0002] Figure 6 A plan view of a conventional permanent magnet motor rotor is shown. The rotor core 1' has 12 magnet slots, each consisting of a V-shaped mounting slot 10', into which magnets 2' are inserted one by one. A careful analysis of this structure reveals the following technical shortcomings:

[0003] The permanent magnet motor using this rotor has high vibration and noise, low sinusoidal back electromotive force, high cogging torque, and high output torque fluctuation. Utility Model Content

[0004] To overcome the shortcomings of the prior art, the purpose of this utility model is to provide an improved rotor and distributed winding stator-rotor structure for permanent magnet motors.

[0005] Therefore, the present invention provides the following technical solution:

[0006] The improved rotor for permanent magnet motors includes a rotor core and magnets inserted into the rotor core. The rotor core has circumferentially spaced magnet slots arranged axially. Each magnet slot is composed of mounting slots that form a V-shape and are arranged in a one-to-one correspondence with the magnets. Adjacent magnets form magnetic pole centers at the rotor core. The improvement is that each mounting slot has a magnetic barrier cavity arranged axially along the rotor core at its outer end. The magnetic barrier cavity has a wedge-shaped cavity structure, and the inner wall areas of the components of the wedge-shaped cavity are not equal.

[0007] The aforementioned mounting slots each have oppositely arranged outer and inner sidewalls. Each magnetic barrier cavity includes oppositely arranged first and second sidewalls, as well as oppositely arranged outer and inner walls. The first sidewall is connected to the corresponding outer sidewall of the mounting slot, and the inner wall is connected to the corresponding inner sidewall of the mounting slot. The second sidewall is connected to the inner wall and the outer wall respectively, and the outer wall is also connected to the first sidewall. The first sidewall is a long sidewall and the second sidewall is a short sidewall. The inner wall is a curved surface that protrudes toward the outer edge of the rotor core.

[0008] The first sidewall and the second sidewall are parallel to each other.

[0009] The distance between the first sidewall and the inner wall is less than the width of the mounting groove.

[0010] Another aspect of this invention provides a distributed winding stator-rotor structure, including a stator and an improved rotor for a permanent magnet motor according to this invention, as described above. The stator includes a stator core for distributed winding, stator teeth are circumferentially spaced on the stator core, and stator slots are formed between adjacent stator teeth. The ratio of the number of stator slots to the number of magnet slots is 3:1. Each stator tooth includes a tooth body and a tooth shoe. The surface of each tooth shoe facing the inner hole of the stator core is a concave arc surface, and the curvature of each concave arc surface is greater than the curvature of the inner hole of the stator core. The rotor is rotatably located within the inner hole of the stator core.

[0011] The technical effects of the technical solution adopted in this utility model are as follows: For the built-in rotor, the rotor core is provided with two mounting slots that form each V-shaped magnet slot. The top of each of these two mounting slots has a wedge-shaped magnetic barrier cavity with the tip extending towards the center of the magnetic pole. In particular, the magnetic circuit can be optimized after the first sidewall of the magnetic barrier cavity is designed to be inclined. Therefore, the sinusoidal nature of the back electromotive force is greatly improved, the harmonic components are reduced, and the vibration and noise of the permanent magnet motor are reduced.

[0012] When each stator tooth in the stator core is designed with a concave arc shape, the cogging torque of the permanent magnet motor can be greatly reduced, resulting in low output torque fluctuation. Attached Figure Description

[0013] Figure 1 This is a plan view of the improved rotor for the permanent magnet motor of this utility model;

[0014] Figure 2 yes Figure 1 Enlarged view of part A;

[0015] Figure 3 It is a plan view of the stator core;

[0016] Figure 4 yes Figure 3 Enlarged view of part B;

[0017] Figure 5 This is a schematic diagram of the distributed winding stator and rotor structure of this utility model;

[0018] Figure 6 This is a plan view of the existing rotor. Detailed Implementation

[0019] Please see Figures 1-2As shown, the improved rotor for permanent magnet motor provided by this utility model includes a rotor core 1 and magnets 2 inserted into the rotor core. The rotor core 1 has circumferentially spaced magnet slots (12 shown in the figure) axially. Each magnet slot is composed of mounting slots 10 that form a V-shape and are arranged in a one-to-one correspondence with the magnets 2. Adjacent magnets form magnetic pole centers 11 in the rotor core. The improvement is that each mounting slot 10 has a magnetic barrier cavity 3 that is opened along the axial direction of the rotor core 1 at its outer end. The magnetic barrier cavity 3 is a wedge-shaped cavity structure, and the areas of the inner walls of each component of the wedge-shaped cavity are not equal.

[0020] The aforementioned mounting slots each have oppositely arranged outer sidewalls 10E and inner sidewalls 10I. In adjacent mounting slots of adjacent magnet slots, the sidewalls that are close together are outer sidewalls, while the sidewalls that are far apart are inner sidewalls. Each magnetic barrier cavity 3 includes oppositely arranged first sidewalls 3L and second sidewalls 3S, as well as oppositely arranged outer wall 3E and inner wall 3I. The first sidewall 3L is connected to the outer sidewall 10E, the inner wall 3I is intersected and connected to the inner sidewall 10I, the second sidewall 3S is intersected and connected to the inner wall 3I and the outer wall 3E respectively, and the other end of the outer wall 3E is also intersected and connected to the first sidewall 3L. The first sidewall 3L is a long sidewall, while the second sidewall 3S is a short sidewall, and the inner wall 3I is a curved surface that protrudes toward the outer edge of the rotor core 1.

[0021] The first sidewall 3L and the second sidewall 3S are parallel to each other; the distance between the first sidewall 3L and the inner wall 3I is less than the width of the mounting groove 10.

[0022] The improved rotor for the permanent magnet motor described in the above embodiments is applied in a permanent magnet motor, i.e., according to another aspect of the present invention. Please refer to [link to previous text]. Figure 5 and 3 ~4 provides a distributed winding stator-rotor structure, including a stator and a rotor configured with the aforementioned improved permanent magnet motor. The stator includes a stator core 4 for distributed winding. The stator core 4 has stator teeth 41 arranged circumferentially at intervals, and stator slots 40 (36 shown in the figure) are formed between adjacent stator teeth. The stator teeth 41 include tooth bodies 411 and tooth shoes 412. Each tooth shoe 412 has a concave arc surface 4120 facing the inner hole of the stator core 4. The curvature of each concave arc surface 4120 is greater than the curvature of the inner hole of the stator core 4. The rotor is rotatably located in the inner hole of the stator core.

[0023] When the curvature of each concave arc surface 4120 is greater than the curvature of the inner hole of the stator core 4, the rotor core 1 and the stator core 4 have unequal gaps, that is, the gaps from the center of the concave arc surface 4120 of each tooth shoe 412 to the two ends of the concave arc surface 4120 gradually decrease from large to small.

[0024] In a distributed winding stator and rotor consisting of a stator with 36 stator teeth and 36 stator slots and a rotor with 12 magnet slots, it has been verified that the cogging torque can be reduced by 62.78% and the output torque fluctuation can be reduced by 44.4%.

Claims

1. An improved rotor for a permanent magnet motor, comprising a rotor core and magnets inserted into the rotor core, wherein the rotor core has circumferentially spaced magnet slots arranged axially, each magnet slot consisting of mutually forming V-shaped mounting slots and corresponding one-to-one with the magnets, and adjacent magnets forming magnetic pole centers at the rotor core, characterized in that: Each mounting slot has a magnetic barrier cavity that is opened along the axial direction of the rotor core at its outer end. The magnetic barrier cavity has a wedge-shaped cavity structure, and the areas of the inner walls of each wedge-shaped cavity are not equal.

2. The improved rotor for a permanent magnet motor according to claim 1, characterized in that: The mounting slots each have oppositely arranged outer and inner sidewalls. Each magnetic barrier cavity includes oppositely arranged first and second sidewalls, as well as oppositely arranged outer and inner walls. The first sidewall connects to the corresponding outer sidewall of the mounting slot, the inner wall intersects with the corresponding inner sidewall of the mounting slot, the second sidewall intersects with both the inner and outer walls, and the outer wall also intersects with the first sidewall. The first sidewall is a long sidewall and the second sidewall is a short sidewall, while the inner wall is a curved surface that bulges outward toward the outer edge of the rotor core.

3. The improved rotor for a permanent magnet motor according to claim 2, characterized in that: The first sidewall and the second sidewall are parallel to each other.

4. The improved rotor for a permanent magnet motor according to claim 2, characterized in that: The distance between the first sidewall and the inner wall is less than the width of the mounting groove.

5. A distributed winding stator-rotor structure, characterized in that: The invention includes a stator and an improved rotor for a permanent magnet motor according to any one of claims 1 to 4. The stator includes a stator core for distributing windings, stator teeth are circumferentially spaced on the stator core, stator slots are formed between adjacent stator teeth, the stator teeth include a tooth body and a tooth shoe, each tooth shoe surface facing the inner hole of the stator core is a concave arc surface, the curvature of each concave arc surface is greater than the curvature of the inner hole of the stator core, and the rotor is rotatably located in the inner hole of the stator core.

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