Fractional slot concentrated winding outer rotor permanent magnet motor

Abstract

The utility model discloses a fractional-slot concentrated winding outer rotor permanent magnet motor, which comprises an inner stator assembly positioned on the inner periphery and an outer rotor assembly positioned on the outer periphery, and is characterized in that a winding of the inner stator assembly adopts a fractional-slot concentrated winding structure; the outer rotor assembly comprises a plurality of permanent magnets which are fixedly arranged on the inner side wall surface of the motor shell and are uniformly and circumferentially distributed at intervals, and a first permanent magnet surface, adjacent to the winding, of each permanent magnet is in an arc-shaped convex shape relative to the winding; the distance between the first permanent magnet surface protruding point located in the middle and the winding is larger than the distance between the first permanent magnet surface protruding point located in the non-middle position and the winding. According to the utility model, harmonic waves and torque pulsation of the fractional-slot concentrated winding outer rotor permanent magnet motor are substantially weakened, magnetic noise during operation of the motor is reduced, a vibration value during operation of the motor is reduced, and the service life of the motor installation structure is prolonged; and the rotation of the motor is smoother.

Description

Technical Field

[0001] This utility model belongs to the field of fractional slot concentrated winding motors, specifically relating to a fractional slot concentrated winding external rotor permanent magnet motor. Background Technology

[0002] Because fractional-slot concentrated winding external rotor permanent magnet motors have advantages over fractional-slot distributed winding motors, such as low magnetic circuit reluctance and short winding span, they have high power density, high efficiency, and low cost, making them suitable for more industry applications. However, they also have disadvantages that are unacceptable in many application areas, such as high magnetic noise and significantly larger motor vibration.

[0003] Therefore, the applicant hopes to find a technical solution to improve the above-mentioned technical problems. Summary of the Invention

[0004] In view of this, the purpose of this utility model is to provide a fractional-slot concentrated winding external rotor permanent magnet motor, which significantly reduces the harmonics and torque pulsation of the fractional-slot concentrated winding external rotor permanent magnet motor, reduces the magnetic noise during motor operation, reduces the vibration value during motor operation, and improves the service life of the motor mounting structure; moreover, it makes the motor rotate more smoothly.

[0005] The technical solution adopted in this utility model is as follows:

[0006] A fractional-slot concentrated winding external rotor permanent magnet motor includes an inner stator assembly located on the inner periphery and an outer rotor assembly located on the outer periphery. The winding of the inner stator assembly adopts a fractional-slot concentrated winding structure. The outer rotor assembly includes a plurality of permanent magnets fixedly disposed on the inner wall of the motor housing and evenly distributed circumferentially. The first permanent magnet surface adjacent to the winding is arc-shaped and convex relative to the winding. The distance between the convex point of the first permanent magnet surface located in the middle position and the winding is larger than the distance between the convex point of the first permanent magnet surface located in the non-middle position and the winding.

[0007] Preferably, the distance between the first permanent magnet protrusion at the end position and the winding is smaller than the distance between the first permanent magnet protrusion at the non-end position and the winding.

[0008] Preferably, the thickness of the permanent magnet corresponding to the first permanent magnet protrusion point located in the middle position is 1.02-1.6 times, more preferably 1.05-1.4 times, the thickness of the permanent magnet corresponding to the first permanent magnet protrusion point located at the end position.

[0009] Preferably, the distance between the first permanent magnet surface protrusion point located at the left end and the winding is equal to the distance between the first permanent magnet surface protrusion point located at the right end and the winding.

[0010] Preferably, the second permanent magnet fixedly disposed on the inner wall of the motor housing has an arc shape or a planar shape.

[0011] Preferably, the second permanent magnet surface, which is fixedly disposed on the inner wall of the motor housing, has an arc-shaped convex shape relative to the inner wall of the motor housing.

[0012] Preferably, the front projection of the first permanent magnet surface is rectangular or square.

[0013] Preferably, the permanent magnets that are evenly spaced circumferentially are arranged in a spaced-apart or full-apart configuration; wherein, the spaced-apart configuration means that the circumferentially adjacent permanent magnets are separated by air or by a filler material; the full-apart configuration means that the circumferentially adjacent permanent magnets are closely adjacent to each other and there is no other material separating them.

[0014] Preferably, in the interlocking arrangement, the spacing between circumferentially adjacent permanent magnets is 5-35% of the width of the permanent magnet; wherein, the width of the permanent magnet refers to the dimension of the permanent magnet extending circumferentially in the motor housing.

[0015] Preferably, the number of permanent magnets along the axial direction of the motor housing is one or two or more spaced apart.

[0016] Preferably, the motor housing includes a stretched member integrally formed, wherein the sidewall of the stretched member serves as the yoke of the motor rotor, and its bottom serves as the motor end cover, and the bottom is provided with several reinforcing ribs.

[0017] This invention features a specific magnetic circuit design for a fractional-slot concentrated winding external rotor permanent magnet motor, which significantly reduces harmonics, thereby alleviating magnetic noise during motor operation. Simultaneously, it significantly reduces torque pulsation, thus reducing vibration during motor operation, lowering the risk of loosening of fixing screws, and extending the service life of the motor mounting structure. Furthermore, it effectively reduces cogging torque, resulting in smoother motor rotation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the outer rotor assembly according to a specific embodiment of the present invention;

[0019] Figure 2 yes Figure 1 Enlarged view of the structure at point A in the image;

[0020] Figure 3 yes Figure 2 Sectional view along the AA direction;

[0021] Figure 4yes Figure 2 Enlarged view of the structure at point B in the image;

[0022] Figure 5 This is a partial magnetic circuit structure diagram of a fractional-slot concentrated winding external rotor permanent magnet motor according to a specific embodiment of this utility model;

[0023] Figure 6 This is a torque pulsation diagram of a fractional-slot concentrated winding external rotor permanent magnet motor according to a specific embodiment of this utility model;

[0024] Figure 7 This is a harmonic diagram of a fractional-slot concentrated winding external rotor permanent magnet motor according to a specific embodiment of this utility model;

[0025] Figure 8 This is a partial magnetic circuit structure diagram of a proportional fractional slot concentrated winding external rotor permanent magnet motor.

[0026] Figure 9 This is a torque pulsation diagram of a proportional fractional slot concentrated winding external rotor permanent magnet motor;

[0027] Figure 10 This is a harmonic diagram of a proportional fractional slot concentrated winding external rotor permanent magnet motor. Detailed Implementation

[0028] This utility model discloses a fractional-slot concentrated winding external rotor permanent magnet motor, including an inner stator assembly located on the inner periphery and an outer rotor assembly located on the outer periphery. The winding of the inner stator assembly adopts a fractional-slot concentrated winding structure. The outer rotor assembly includes a plurality of permanent magnets fixedly disposed on the inner wall of the motor housing and evenly distributed circumferentially. The first permanent magnet surface adjacent to the winding is arc-shaped and convex relative to the winding. The distance between the convex point of the first permanent magnet surface located in the middle position and the winding is larger than the distance between the convex point of the first permanent magnet surface located in the non-middle position and the winding.

[0029] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0030] Please refer to the above. Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, a fractional-slot concentrated winding external rotor permanent magnet motor includes an inner stator assembly located on the inner circumference and an outer rotor assembly located on the outer circumference. The winding of the inner stator assembly adopts a fractional-slot concentrated winding structure. The outer rotor assembly includes a plurality of permanent magnets 12 fixedly disposed on the inner wall 11a of the motor housing 11 and evenly circumferentially spaced. Among the permanent magnets 12, the first permanent magnet surface 12a adjacent to the winding is arc-shaped and protrudes relative to the winding. The distance between the first permanent magnet surface protrusion 121 located in the middle position and the winding is greater than the distance between the first permanent magnet surface protrusion 121 located in the non-middle position and the winding. Preferably, in this embodiment, the distance between the first permanent magnet surface protrusion 122 located at the end position and the winding is smaller than the distance between the first permanent magnet surface protrusion 123 located in the non-end position and the winding. More preferably, in this embodiment, the distance between the first permanent magnet surface protrusion 122 located at the left end position and the winding is equal to the distance between the first permanent magnet surface protrusion 123 located at the right end position and the winding.

[0031] Preferably, in this embodiment, the thickness of the permanent magnet corresponding to the first permanent magnet surface protrusion 121 located in the middle position is 1.02-1.6 times, more preferably 1.05-1.4 times, the thickness of the permanent magnet corresponding to the first permanent magnet surface protrusion 122, 123 located at the end positions.

[0032] Preferably, in this embodiment, the second permanent magnet surface 12b fixedly disposed on the inner wall 11a of the motor housing in each permanent magnet 12 is arc-shaped or planar; wherein preferably, the second permanent magnet surface 12b fixedly disposed on the inner wall 11a of the motor housing in each permanent magnet 12 is arc-shaped and protrudes relative to the inner wall 11a of the motor housing, and is tightly attached to the inner wall 11a of the motor housing.

[0033] In this embodiment, the permanent magnet 12 can be made of any known permanent magnet material. Preferably, in this embodiment, the permanent magnet 12 is made of neodymium iron boron material.

[0034] It should be noted that, in specific implementation, the appropriate number of permanent magnets is selected according to the magnetic slot matching requirements. The height (i.e., axial length) and thickness of the permanent magnet 12 are designed according to the requirements of motor power and performance. The width of the permanent magnet 12 is specifically set according to the inner diameter of the outer rotor assembly and the arrangement of the permanent magnet 12. This embodiment does not impose specific limitations on it.

[0035] Preferably, in this embodiment, the front projection of the first permanent magnet surface 12a is rectangular or square. More specifically, in this embodiment, the front projection of the first permanent magnet surface 12a is rectangular.

[0036] Preferably, in this embodiment, the several permanent magnets 12 that are evenly circumferentially spaced are arranged in a spaced-together or fully attached manner; wherein, the spaced-together arrangement means that the circumferentially adjacent permanent magnets 12 are separated by air or by filler material; the fully attached arrangement means that the circumferentially adjacent permanent magnets 12 are closely adjacent to each other and there is no other material separating them. The specific arrangement method can be selected according to actual needs, and this embodiment does not impose a unique limitation on it; further preferably, in this embodiment, the several permanent magnets 12 that are evenly circumferentially spaced are arranged in a spaced-together manner, and the circumferentially adjacent permanent magnets 12 are separated by air; more preferably, in this embodiment, the spacing between the circumferentially adjacent permanent magnets 12 is 5-35% of the width of the permanent magnet; wherein, the width of the permanent magnet refers to the dimension of the permanent magnet 12 extending in the circumferential direction of the motor housing 11.

[0037] Preferably, in this embodiment, the number of permanent magnets 12 along the axial direction of the motor housing 11 is one or two or more spaced apart; preferably, when the number of permanent magnets along the axial direction of the motor housing is two or more, the permanent magnets are all permanent magnets with the same polarity; more specifically, in this embodiment, the permanent magnets 12 along the axial direction of the motor housing are two permanent magnets 12 spaced apart and with the same polarity.

[0038] Preferably, in this embodiment, the motor housing 11 includes a stretched member formed by integral processing (more preferably a basin-shaped or barrel-shaped housing obtained by stretching an iron plate with a thickness of 2-10mm). The sidewall of the stretched member serves as the yoke of the motor rotor (its inner wall surface is the inner sidewall surface 11a of the motor housing), and its bottom 11b serves as the motor end cover, with a motor bearing 14 installed on its inner circumference. At the same time, the bottom 11b is provided with a plurality of reinforcing ribs 13. The reinforcing ribs 13 are preferably integrally stamped reinforcing rib structures (the shape of the reinforcing ribs can be specifically designed according to actual needs, and this embodiment does not impose specific limitations on them), thereby strengthening the structure of the motor housing 11.

[0039] More preferred solutions for the motor housing 11 in this embodiment can be found in the preferred technical solution of the housing of the external rotor permanent magnet motor of the ceiling fan provided in the applicant's prior patent (authorization announcement number CN220732486U). This embodiment will not elaborate on them one by one.

[0040] Preferably, in this embodiment, the outer diameter of the motor housing 11 is in the range of 200-700mm, and the stretching depth is 30-200mm.

[0041] Comparative Example: The remaining technical solutions of this comparative example are the same as those of the above embodiments, except that: in this comparative example, the permanent magnets in the above embodiments are replaced with: the second permanent magnet surface 12b of each permanent magnet 12, which is fixedly disposed on the inner wall surface 11a of the motor housing, has an arc-shaped convex shape relative to the inner wall surface 11a of the motor housing and is tightly attached to the inner wall surface 11a of the motor housing; the first permanent magnet surface 12a and the second permanent magnet surface 12b are parallel to each other and have the same shape and size as the second permanent magnet surface 12b.

[0042] To verify the technical effects achieved by the embodiments of this application, the applicant has provided a fractional-slot concentrated winding external rotor permanent magnet motor in this embodiment and in comparison (please refer to the respective embodiments). Figure 5 The embodiment shown provides a magnetic circuit structure diagram of a fractional-slot concentrated winding external rotor permanent magnet motor and... Figure 8 The comparative diagram shown (providing the magnetic circuit structure of a fractional-slot concentrated winding external rotor permanent magnet motor) underwent torque pulsation and harmonic tests. The test results can be found in the respective diagrams. Figure 6 , Figure 7 , Figure 9 and Figure 10 As shown, it is evident that the fractional-slot concentrated winding external rotor permanent magnet motor provided in this embodiment significantly reduces the harmonics of the fractional-slot concentrated winding external rotor permanent magnet motor, thereby reducing the magnetic noise during motor operation; at the same time, it also significantly reduces the torque pulsation (i.e., torque pulsation) of the fractional-slot concentrated winding external rotor permanent magnet motor, thereby reducing the vibration value during motor operation, reducing the risk of loosening of fixing screws, and improving the service life of the motor mounting structure; moreover, it effectively reduces the cogging torque of the motor, making the motor rotate more smoothly.

[0043] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0044] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A fractional-slot concentrated winding external rotor permanent magnet motor, characterized in that, The device includes an inner stator assembly located on the inner periphery and an outer rotor assembly located on the outer periphery. The windings of the inner stator assembly adopt a fractional slot concentrated winding structure. The outer rotor assembly includes a plurality of permanent magnets fixedly disposed on the inner wall of the motor housing and evenly distributed circumferentially. The first permanent magnet surface adjacent to the winding is arc-shaped and protrudes relative to the winding. The distance between the protrusion point of the first permanent magnet surface located in the middle position and the winding is larger than the distance between the protrusion point of the first permanent magnet surface located in the non-middle position and the winding.

2. The fractional-slot concentrated winding external rotor permanent magnet motor according to claim 1, characterized in that, The distance between the first permanent magnet surface protrusion at the end position and the winding is smaller than the distance between the first permanent magnet surface protrusion at the non-end position and the winding.

3. The fractional-slot concentrated winding external rotor permanent magnet motor according to claim 1 or 2, characterized in that, The thickness of the permanent magnet corresponding to the first permanent magnet protrusion point located in the middle position is 1.02-1.6 times, preferably 1.05-1.4 times, the thickness of the permanent magnet corresponding to the first permanent magnet protrusion point located at the end position.

4. The fractional-slot concentrated winding external rotor permanent magnet motor according to claim 2, characterized in that, The distance between the first permanent magnet protrusion point located at the left end and the winding is equal to the distance between the first permanent magnet protrusion point located at the right end and the winding.

5. The fractional-slot concentrated winding external rotor permanent magnet motor according to claim 1, characterized in that, The second permanent magnet, which is fixedly disposed on the inner wall of the motor housing, has an arc-shaped or planar surface.

6. The fractional-slot concentrated winding external rotor permanent magnet motor according to claim 1, characterized in that, The second permanent magnet, which is fixedly disposed on the inner wall of the motor housing, has an arc-shaped convex shape relative to the inner wall of the motor housing.

7. The fractional-slot concentrated winding external rotor permanent magnet motor according to claim 1, characterized in that, The front projection of the first permanent magnet surface is rectangular or square.

8. The fractional-slot concentrated winding external rotor permanent magnet motor according to claim 1, characterized in that, A plurality of permanent magnets, evenly spaced circumferentially, are arranged in a spaced-together or fully-attached manner. The spaced-together arrangement means that circumferentially adjacent permanent magnets are separated by air or by filler material. The fully-attached arrangement means that circumferentially adjacent permanent magnets are closely adjacent to each other without any other material separating them. Preferably, in the spaced-together arrangement, the spacing between circumferentially adjacent permanent magnets is 5-35% of the width of the permanent magnet. The width of the permanent magnet refers to the dimension of the permanent magnet extending circumferentially from the motor housing.

9. The fractional-slot concentrated winding external rotor permanent magnet motor according to claim 1, characterized in that, Along the axial direction of the motor housing, there is one permanent magnet or two or more magnets spaced apart.

10. The fractional-slot concentrated winding external rotor permanent magnet motor according to claim 1, characterized in that, The motor housing includes a stretched part formed by integral machining, wherein the side wall of the stretched part serves as the yoke of the motor rotor, and its bottom serves as the motor end cover, and the bottom is provided with several reinforcing ribs.

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