Rotor lamination, rotor structure and permanent magnet motor

Abstract

This invention provides a rotor lamination, a rotor structure, and a permanent magnet motor. The rotor lamination has: multiple magnetic slots, which are sequentially spaced along the circumference of the rotor lamination; multiple recesses, all located on the edge of the rotor lamination and sequentially spaced along the circumference of the rotor lamination, wherein at least a portion of any recess is located between two adjacent magnetic slots along the circumference of the rotor lamination; and multiple grooves, each corresponding to one of the recesses, wherein any groove is located at the bottom of its corresponding recess and is recessed towards the interior of the rotor lamination. The rotor structure of this invention solves the technical problem of easy breakage of the magnetic isolation bridge between adjacent magnetic poles in related technologies.

Description

Technical Field

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

[0002] In permanent magnet synchronous motors (PMSMs) of related technologies, adjacent magnetic poles are connected by a magnetic isolation bridge to reduce magnetic circuit losses between adjacent poles. Furthermore, the thickness of the magnetic isolation bridge is typically small to ensure minimal leakage flux. However, in PMSMs with this design, the structural strength of the magnetic isolation bridge is relatively low. Especially during the heat-shrinking process after rotor lamination stacking, the magnetic isolation bridge is prone to breakage due to excessively high temperatures, leading to foreign objects falling out.

[0003] It is evident that permanent magnet motors in related technologies suffer from the technical problem of easily broken magnetic bridges between adjacent magnetic poles, and no effective solution has yet been proposed to address this issue. Summary of the Invention

[0004] The main objective of this invention is to provide a rotor lamination, a rotor structure, and a permanent magnet motor to solve the technical problem of easy breakage of the magnetic isolation bridge between adjacent magnetic poles in the related art.

[0005] To achieve the above objectives, according to one aspect of the present invention, a rotor lamination is provided, the rotor lamination having: a plurality of magnet slots, the plurality of magnet slots being arranged sequentially at intervals along the circumference of the rotor lamination; a plurality of recesses, the plurality of recesses being disposed at the edge of the rotor lamination, the plurality of recesses being arranged sequentially at intervals along the circumference of the rotor lamination, and for any given recess, along the circumference of the rotor lamination, it is at least partially located between two adjacent magnet slots; and a plurality of grooves, the positions of the plurality of grooves corresponding one-to-one with the plurality of recesses, wherein for any given groove, it is disposed at the bottom of the corresponding recess, and the groove is recessed toward the interior of the rotor lamination.

[0006] Furthermore, for any given groove, it extends radially into the space between two adjacent magnet slots along the rotor lamination.

[0007] Furthermore, for any recessed portion and / or grooved portion, it is symmetrical with respect to a preset axis, and the magnetic grooves on both sides of the recessed portion and / or grooved portion are symmetrical with respect to the preset axis.

[0008] Furthermore, the structure of the rotor lamination satisfies 0.35≤d1≤0.5, where d1 is the minimum distance between the inner surface of any recess and its nearest magnet slot.

[0009] Furthermore, the structure of the rotor lamination satisfies 0.85≤2×d2 / D1≤0.92, 21mm≤d2≤23mm, where d2 is the distance between the groove and the center of the rotor lamination, and D1 is the diameter of the outer tangent circle of the rotor lamination.

[0010] Furthermore, the magnetic steel slot includes a first slot segment and a second slot segment, which together form a V-shaped slot. The opening direction of the V-shaped slot is away from the center of the rotor lamination. The structure of the rotor lamination satisfies 0.28≤θ1 / θ2≤0.37 and 13°≤θ1≤17°, where θ1 is the angle formed by the lines connecting the first endpoint and the second endpoint to the center of the rotor lamination, and the first endpoint and the second endpoint are the two ends of any recess along the circumference of the rotor lamination. θ2 is the angle formed by the lines connecting the third endpoint and the fourth endpoint to the center of the rotor lamination, and the third endpoint is the endpoint on the first slot segment that is farthest from the center of the rotor lamination, and the fourth endpoint is the endpoint on the second slot segment that is farthest from the center of the rotor lamination.

[0011] According to another aspect of the present invention, a rotor structure is provided, the rotor structure comprising a plurality of rotor laminations stacked sequentially, the rotor laminations being the rotor laminations described above.

[0012] Furthermore, a magnet is installed in any magnet slot of the rotor lamination, wherein the distance between the magnet and the preset end face ranges from 0.3mm to 2mm, and the preset end face is the end face of the magnet slot that is closest to the corresponding recess.

[0013] According to another aspect of the present invention, a permanent magnet motor is provided, the permanent magnet motor including a stator structure and a rotor structure, wherein the rotor structure is the rotor structure described above, and the stator structure is designed around the rotor structure.

[0014] Furthermore, the structure of the permanent magnet motor satisfies 0.49≤D1 / D2≤0.56, where 96≤D2≤112, and D1 is the outer circle diameter of the rotor structure, and D2 is the outer circle diameter of the stator structure.

[0015] The rotor lamination of this invention includes: multiple magnet slots, which are sequentially spaced along the circumference of the rotor lamination; multiple recesses, all located at the edge of the rotor lamination and sequentially spaced along the circumference of the rotor lamination; and multiple grooves, each corresponding to one of the recesses, wherein each groove is located at the bottom of its corresponding recess and is recessed towards the interior of the rotor lamination. This design allows the rotor lamination to recess further into a deeper location by providing recesses at the edge of the rotor lamination corresponding to the spaces between two magnet slots, and by providing grooves at the bottom of the recesses. This structure, which incorporates recesses and grooves between adjacent magnet slots, increases the length of the leakage magnetic circuit between magnetic poles, reduces leakage magnetic flux, and thus increases the effective magnetic properties of the poles. While minimizing the impact on the structural strength of the rotor laminations, it maximizes the leakage magnetic reluctance, improves the motor's back electromotive force, and ensures high efficiency for the permanent magnet motor. Rotor laminations with this design do not require gaps between adjacent magnet slots to form a magnetic isolation bridge; the design of recesses and grooves is sufficient to guarantee magnetic properties. This solves the technical problem of easily broken magnetic isolation bridges between adjacent magnetic poles in related technologies, increasing the reliability and service life of the permanent magnet motor. Attached Figure Description

[0016] 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:

[0017] Figure 1 This is a schematic diagram of the structure of an embodiment of the rotor lamination of the present invention;

[0018] Figure 2 This is a partial structural diagram of a rotor lamination in a related technology;

[0019] Figure 3 This is a schematic diagram of an embodiment of the rotor structure of the present invention;

[0020] Figure 4 for Figure 3 Enlarged schematic diagram of some of the structures in the diagram;

[0021] Figure 5 This is a schematic diagram of the structure of an embodiment of the permanent magnet motor of the present invention;

[0022] Figure 6 This is a schematic diagram comparing the no-load back electromotive force coefficient and motor efficiency of the permanent magnet motor in this embodiment of the invention with those of permanent magnet motors in related technologies.

[0023] Figure 7 This is a schematic diagram comparing the rotor magnetic bridge strength of a permanent magnet motor according to an embodiment of the present invention with that of a permanent magnet motor in related technologies.

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

[0025] 1. Magnet slot; 11. First slot section; 12. Second slot section; 2. Recessed part; 3. Groove part; 4. Magnet; 5. Gap; 6. Magnetic bridge; 10. Stator structure; 20. Rotor structure. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] Please refer to Figures 1 to 7 To achieve the above objectives, embodiments of the present invention provide a rotor lamination having: a plurality of magnet slots 1, the plurality of magnet slots 1 being arranged sequentially at intervals along the circumference of the rotor lamination; a plurality of recesses 2, the plurality of recesses 2 being disposed on the edge of the rotor lamination, the plurality of recesses 2 being arranged sequentially at intervals along the circumference of the rotor lamination, and for any recess 2, along the circumference of the rotor lamination, it is at least partially located between two adjacent magnet slots 1; and a plurality of grooves 3, the plurality of grooves 3 corresponding one-to-one with the plurality of recesses 2, wherein for any groove 3, it is disposed at the bottom of the corresponding recess 2, and the groove 3 is recessed toward the interior of the rotor lamination.

[0028] The rotor lamination with this structural design has a recessed portion 2 at the edge of the lamination corresponding to the position between two magnet slots 1, and a grooved portion 3 is further provided at the bottom of the recessed portion 2. The grooved portion 3 is located at the bottom of the recessed portion 2, so it can be recessed further into a deeper position. This structure of recess + groove between adjacent magnet slots 1 can increase the length of the leakage magnetic circuit between magnetic poles, reduce leakage magnetic flux, and thus increase the effective magnetic performance of the magnetic poles. While ensuring that the impact on the structural strength of the rotor lamination is minimal, the leakage magnetic reluctance is increased as much as possible, the back electromotive force of the motor is improved, and the efficiency of the permanent magnet motor is guaranteed. The rotor lamination with this structural design does not require the design of a gap between adjacent magnet slots to form a magnetic isolation bridge. Instead, the design of recessed portion 2 and grooved portion 3 is sufficient to ensure magnetic performance. This solves the technical problem of easy breakage of the magnetic isolation bridge between adjacent magnetic poles in related technologies, and increases the reliability and service life of the permanent magnet motor.

[0029] Specifically, the magnetic lines of force generated by the rotor magnets of a permanent magnet motor originate from the N pole, pass through the air gap between the stator and rotor, reach the stator teeth and yoke, then pass through the air gap again, and return to the S pole of the adjacent magnetic pole on the rotor. This loop is an effective magnetic loop and performs effective work for the motor. However, on a single magnetic pole, some of the magnetic lines of force emanating from its N pole may pass through a magnetic bridge or narrow section to reach the S pole on the opposite side of that pole; this part of the magnetic loop is an ineffective loop. For example... Figure 2 As shown, in related technologies, a gap 5 extending circumferentially along the rotor lamination is designed at the end of the magnet slot, thereby forming a magnetic isolation bridge 6 between adjacent magnetic poles on the rotor lamination. However, this gap 5 structure can significantly compromise the rigidity of the rotor structure, making the magnetic isolation bridge 6 prone to breakage. In this embodiment, a recessed portion 2 and a grooved portion 3 are designed between adjacent magnet slots 1 to increase the length and reduce the width of the leakage magnetic circuit, thereby effectively reducing leakage magnetic flux and ensuring the magnetic performance of the permanent magnet motor. This structure causes less damage to the permanent magnet motor rotor structure, effectively improving the rotor structural strength and solving the technical problem of easy breakage of the magnetic isolation bridge between adjacent magnetic poles in the related technologies.

[0030] Regarding the aforementioned recessed portion 2, it is located at the edge of the rotor lamination, meaning the edge of the rotor lamination has multiple notches that are recessed towards the interior of the rotor lamination. The interior of the rotor lamination is its center, opposite to the exterior. It should be noted that the recessed portion 2 being recessed towards the interior of the rotor lamination does not mean that the recessed portion 2 is strictly recessed towards the center of the rotor lamination; it can also have a certain inclination. In other words, the so-called recessed portion 2 being recessed towards the interior of the rotor lamination only requires that the direction of the recessed portion 2 is away from the edge of the rotor lamination. Similarly, the recessed direction of the groove portion 3 should also be understood as being towards the edge of the rotor lamination, not strictly towards the center of the rotor lamination. The groove portion 3 is located at the bottom of the recessed portion 2, so it can be further recessed to a deeper position. This maximizes the leakage magnetic reluctance while minimizing the impact on the structural strength of the rotor lamination, reducing the leakage magnetic flux between the poles of the magnets in the same magnet slot 1, and improving the efficiency of the permanent magnet motor.

[0031] Wherein, for any one of the recesses 2, along the circumferential direction of the rotor lamination, it is at least partially located between two adjacent magnet slots 1. Here, the circumferential position of the recess 2 is defined, that is, along the circumferential direction of the rotor lamination, it is at least partially located between two magnet slots 1, rather than meaning that the recess 2 extends radially into the space between two magnet slots 1.

[0032] In a preferred embodiment, for any one groove 3, it extends radially into the space between two adjacent magnet slots 1.

[0033] In other words, the groove 3 is a structure that fully penetrates between the two magnet slots 1, thereby increasing the length of the leakage magnetic circuit between the two poles of the same magnet and making the leakage magnetic position narrower, thereby further reducing the leakage magnetic field, increasing the effective magnetic properties of the magnetic poles, and improving the back electromotive force and performance of the motor.

[0034] Along the direction extending into the rotor lamination, the opening size of the recess 2 gradually decreases; and / or, along the direction extending into the rotor lamination, the opening size of the groove 3 gradually decreases.

[0035] In this embodiment, any recessed portion 2 and / or grooved portion 3 is symmetrical with respect to a preset axis, and the magnetic grooves 1 on both sides of the recessed portion 2 and / or grooved portion 3 are symmetrical with respect to the preset axis.

[0036] That is, the aforementioned preset axis is the q-axis of the rotor lamination, which is the center line between adjacent magnet slots 1. For a set of phase recesses 2, grooves 3 and the two magnet slots 1 on both sides thereon, they are all symmetrical with respect to the preset axis.

[0037] Specifically, the structure of the rotor lamination satisfies 0.35≤d1≤0.5, where d1 is the minimum distance between the inner surface of any recess 2 and its nearest magnet slot 1.

[0038] In this embodiment, as Figure 1 and Figure 3 As shown, by designing the minimum distance between the recessed part 2 and the adjacent magnet slot 1 such that 0.35≤d1≤0.5, leakage flux can be effectively reduced while ensuring the strength of the rotor structure. This avoids excessive leakage flux due to an excessively large distance design, and also avoids processing difficulties and reduced rotor structural strength due to an excessively small distance design.

[0039] Specifically, the structure of the rotor lamination satisfies 0.85≤2×d2 / D1≤0.92, 21mm≤d2≤23mm, where d2 is the distance between the groove 3 and the center of the rotor lamination, and D1 is the diameter of the outer tangent circle of the rotor lamination.

[0040] This embodiment designs the dimensional relationship between d2 and D1 to ensure that 0.85 ≤ 2×d2 / D1 ≤ 0.92. Specifically, if 2×d2 / D1 is designed to be too large, the recess depth of the groove 3 will be too small, resulting in a smaller increase in leakage flux and magnetic reluctance, thus reducing the improvement in motor performance. If 2×d2 / D1 is designed to be too small, the recess of the groove 3 will be too deep, which will adversely affect the strength of the rotor structure. In this embodiment, designing 2×d2 / D1 to be 0.85 ≤ 2×d2 / D1 ≤ 0.92 effectively balances leakage flux and rotor structural strength, especially for permanent magnet motors with 21mm ≤ d2 ≤ 23mm, which has good practical application value.

[0041] Specifically, the magnetic slot 1 includes a first slot segment 11 and a second slot segment 12, which form a V-shaped slot. The opening direction of the V-shaped slot is away from the center of the rotor lamination. The structure of the rotor lamination satisfies 0.28≤θ1 / θ2≤0.37 and 13°≤θ1≤17°, where θ1 is the angle formed by the lines connecting the first endpoint and the second endpoint to the center of the rotor lamination, the first endpoint and the second endpoint are the two ends of any recess 2 along the circumference of the rotor lamination, and θ2 is the angle formed by the lines connecting the third endpoint and the fourth endpoint to the center of the rotor lamination, the third endpoint is the endpoint on the first slot segment 11 that is farthest from the center of the rotor lamination, and the fourth endpoint is the endpoint on the second slot segment 12 that is farthest from the center of the rotor lamination.

[0042] In this embodiment, θ1 / θ2 is also designed so that 0.28≤θ1 / θ2≤0.37. Based on the design of the above-mentioned recessed part 2 and grooved part 3, the rotor lamination structure design can be more reasonable, avoiding the degradation of the motor's cogging torque, torque fluctuation, back EMF harmonic content, etc. due to excessively large or small design.

[0043] Please refer to Figure 3 and Figure 4 The embodiments of the present invention also provide a rotor structure, which includes a plurality of rotor laminations stacked sequentially, wherein the rotor laminations are those described above.

[0044] Specifically, a magnet 4 is installed in any magnet slot 1 of the rotor lamination, wherein the distance between the magnet 4 and the preset end face ranges from 0.3mm to 2mm, i.e. Figure 4 In the d3 section, the preset end face is the end face of the magnet groove 1 that is closest to the corresponding recess 2.

[0045] In this embodiment, the rotor structure has recessed portions 2 and grooved portions 3 designed between adjacent magnet slots 1 of the rotor laminations, thus eliminating the need for further design of... Figure 2 Similar magnetic bridge 6 structures exist in related technologies. Therefore, the distance between the magnet 4 and the preset end face can be designed to be smaller, i.e. less than or equal to 2mm, thereby avoiding the reduction of rotor structural strength. Moreover, in this embodiment, the distance is designed to be greater than or equal to 0.3mm, which can prevent a part of the magnet direction from forming a local magnetic circuit, thereby increasing magnetic leakage. Designing the distance to be greater than or equal to 0.3mm has a significant effect on reducing magnetic leakage.

[0046] Please refer to Figure 5 The embodiments of the present invention also provide a permanent magnet motor, which includes a stator structure 10 and a rotor structure 20, wherein the rotor structure 20 is the rotor structure described above, and the stator structure 10 is designed around the rotor structure 20.

[0047] Specifically, the structure of the permanent magnet motor satisfies 0.49≤D1 / D2≤0.56, where 96≤D2≤112, and D1 is the outer diameter of the rotor structure 20, and D2 is the outer diameter of the stator structure 10.

[0048] like Figure 6 and Figure 7 As shown, Figure 6 This is a schematic diagram comparing the no-load back electromotive force coefficient and motor efficiency of the permanent magnet motor in this embodiment of the invention with those of permanent magnet motors in related technologies. Figure 7 This is a schematic diagram comparing the rotor magnetic bridge strength of the permanent magnet motor in this embodiment of the invention with that of a permanent magnet motor in related technologies. Figure 6 and Figure 7 The original scheme corresponds to a permanent magnet motor in related technologies, while new scheme one and new scheme two correspond to the permanent magnet motors in this invention. The difference between new scheme one and new scheme two lies in the thickness d1 mentioned above. In new scheme one, d1 is 0.5mm, while in new scheme two, d1 is 0.4mm. From Figure 6 As can be seen, compared with the original solutions in related technologies, the new solutions one and two of the present invention have slightly improved no-load back EMF coefficient and motor efficiency. Figure 7 This diagram illustrates a comparison of the rotor magnetic bridge strength of a permanent magnet motor according to an embodiment of the present invention and that of a permanent magnet motor in related technologies. The rotor magnetic bridge strength is the rotor strength limit; the lower the rotor magnetic bridge strength, the less likely it is to experience deformation, breakage, or other strength-related risks. Therefore, the lower the rotor (magnetic bridge) strength of different solutions, the better their reliability. It is evident that new solutions one and two of the present invention are superior to the original solutions and are less prone to magnetic bridge breakage.

[0049] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0050] The rotor lamination of this invention includes: a plurality of magnet slots 1, which are sequentially spaced along the circumference of the rotor lamination; a plurality of recesses 2, each located on the edge of the rotor lamination and spaced along the circumference of the rotor lamination, wherein any recess 2 is at least partially located between two adjacent magnet slots 1 along the circumference of the rotor lamination; and a plurality of grooves 3, each corresponding to one of the recesses 2, wherein any groove 3 is located at the bottom of its corresponding recess 2 and is recessed towards the interior of the rotor lamination. With this structural design, the rotor lamination has recesses 2 located at the edge of the rotor lamination between two magnet slots 1, and grooves 3 are further provided at the bottom of the recesses 2, allowing them to recess further into a deeper location. This structure, which incorporates a recess and groove between adjacent magnet slots 1, increases the length of the leakage magnetic circuit between magnetic poles, reduces leakage magnetic flux, and thus increases the effective magnetic properties of the magnetic poles. While minimizing the impact on the structural strength of the rotor laminations, it maximizes the leakage magnetic reluctance, improves the motor's back electromotive force, and ensures high efficiency for the permanent magnet motor. The rotor laminations with this structure do not require gaps between adjacent magnet slots to form a magnetic isolation bridge; instead, the design of the recess 2 and groove 3 is sufficient to guarantee magnetic properties. This solves the technical problem of easy breakage of the magnetic isolation bridge between adjacent magnetic poles in related technologies, increasing the reliability and service life of the permanent magnet motor.

[0051] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0052] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0053] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0054] 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 provided with: Multiple magnet slots (1) are arranged sequentially at intervals along the circumference of the rotor laminations; Multiple recesses (2) are provided on the edge of the rotor lamination. The multiple recesses (2) are arranged sequentially at intervals along the circumference of the rotor lamination. For any one of the recesses (2), along the circumference of the rotor lamination, at least part of it is located between two adjacent magnet slots (1). Multiple grooves (3) are provided, and the positions of the multiple grooves (3) correspond one-to-one with the positions of the multiple recesses (2). For any one of the grooves (3), it is provided at the bottom of the corresponding recess (2), and the groove (3) is recessed towards the inside of the rotor lamination.

2. The rotor lamination according to claim 1, characterized in that, For any one of the groove portions (3), it extends radially into the space between two adjacent magnet slots (1) along the rotor lamination.

3. The rotor lamination according to claim 1, characterized in that, For any one of the recessed portions (2) and / or the grooved portions (3), it is symmetrical with respect to a preset axis, and the magnetic grooves (1) on both sides of the recessed portions (2) and / or the grooved portions (3) are symmetrical with respect to the preset axis.

4. The rotor lamination according to claim 1, characterized in that, The structure of the rotor lamination satisfies 0.35≤d1≤0.5, where d1 is the minimum distance between the inner surface of any recess (2) and the nearest magnet slot (1).

5. The rotor lamination according to claim 1, characterized in that, The structure of the rotor lamination satisfies 0.85≤2×d2 / D1≤0.92, 21mm≤d2≤23mm, where d2 is the distance between the groove (3) and the center of the rotor lamination, and D1 is the diameter of the outer tangent circle of the rotor lamination.

6. The rotor lamination according to claim 1, characterized in that, The magnet slot (1) includes a first slot section (11) and a second slot section (12), the first slot section (11) and the second slot section (12) form a V-shaped slot, and the opening direction of the V-shaped slot is away from the center of the rotor lamination; The structure of the rotor lamination satisfies 0.28≤θ1 / θ2≤0.37, 13°≤θ1≤17°, where θ1 is the angle formed by the lines connecting the first endpoint and the second endpoint to the center of the rotor lamination, the first endpoint and the second endpoint are the two ends of any recess (2) along the circumference of the rotor lamination, θ2 is the angle formed by the lines connecting the third endpoint and the fourth endpoint to the center of the rotor lamination, the third endpoint is the endpoint on the first slot (11) that is farthest from the center of the rotor lamination, and the fourth endpoint is the endpoint on the second slot (12) that is farthest from the center of the rotor lamination.

7. A rotor structure, characterized in that, The rotor structure includes a plurality of rotor laminations stacked sequentially, wherein the rotor laminations are the rotor laminations according to any one of claims 1 to 6.

8. The rotor structure according to claim 7, characterized in that, For any one of the magnet slots (1) of the rotor lamination, a magnet (4) is installed. The distance between the magnet (4) and the preset end face is in the range of 0.3mm to 2mm. The preset end face is the end face of the magnet slot (1) that is closest to the corresponding recess (2).

9. A permanent magnet motor, characterized in that, The permanent magnet motor includes a stator structure (10) and a rotor structure (20), wherein the rotor structure (20) is the rotor structure as described in claim 7, and the stator structure (10) is designed around the rotor structure (20).

10. The permanent magnet motor according to claim 9, characterized in that, The structure of the permanent magnet motor satisfies 0.49≤D1 / D2≤0.56, where 96≤D2≤112, where D1 is the outer diameter of the rotor structure (20) and D2 is the outer diameter of the stator structure (10).

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