Rotor structure and permanent magnet synchronous motor

Abstract

The utility model relates to the technical field of motors, and discloses a rotor structure and a permanent magnet synchronous motor, because the two sub-permanent magnets of the same primary permanent magnet have the same magnetism and the two primary permanent magnets between adjacent retainers have opposite magnetism, when the permanent magnet synchronous motor works, the magnetic induction lines between the two sub-permanent magnets of the same primary permanent magnet are sparse, so that the permanent magnet synchronous motor is stable in magnetic induction. The magnetic induction lines between the two sub permanent magnets between the two retainers are dense, the retainers are arranged between the two sub permanent magnets of the same mother permanent magnet, the retainers do not need to be arranged between the two mother permanent magnets, and the magnetic flux influence of the arrangement of the retainers on the mother permanent magnets is reduced; the permanent magnet synchronous motor solves the problem that the magnetic flux saturation of a rotor core is reduced due to the fact that a dovetail groove for installing a retainer is formed between two primary permanent magnets in the prior art, the magnetic leakage rate of the rotor structure is reduced, compared with the prior art, the no-load back electromotive force of the permanent magnet synchronous motor is improved, and the utilization rate of the primary permanent magnets is improved.

Description

Technical Field

[0001] The utility model relates to the field of motor technology, in particular to a rotor structure and a permanent magnet synchronous motor. Background Art

[0002] Surface-mounted permanent magnet synchronous motors are widely used due to their simple structure and low cost. Surface-mounted permanent magnet synchronous motors include a rotor core and permanent magnets disposed on the outer peripheral wall of the rotor core. The permanent magnets are usually fixed to the outer peripheral wall of the rotor core by gluing.

[0003] During the rotation of the rotor core, the permanent magnets will be subjected to a large centrifugal force. In order to prevent the permanent magnets from flying away from the rotor core under the action of centrifugal force, a stainless steel sheath is usually installed outside the rotor core. However, during the operation of the surface-mounted permanent magnet synchronous motor, the stainless steel sheath will increase eddy current losses, which will not only increase the risk of high-temperature demagnetization of the permanent magnets, but also reduce the efficiency of the motor.

[0004] To this end, the prior art proposes to use a retainer to mount two adjacent permanent magnets on the rotor core, wherein the outer peripheral wall of the rotor core is provided with a dovetail groove, and one end of the retainer is embedded in the dovetail groove. However, in actual application, it is found that the dovetail groove for mounting the retainer on the rotor core will shorten the radial width of the rotor core near the dovetail groove, which is likely to cause magnetic saturation of the rotor core, a large magnetic leakage rate of the rotor structure, and a low utilization rate of the permanent magnets.

[0005] Therefore, there is an urgent need for a rotor structure to solve the above technical problems. Utility Model Content

[0006] The utility model aims to provide a rotor structure and a permanent magnet synchronous motor, which can reduce the problem of magnetic flux density saturation of the rotor core caused by opening a dovetail groove on the rotor core while ensuring the connection stability between the permanent magnet and the rotor core.

[0007] To achieve this purpose, the utility model adopts the following technical solutions:

[0008] A rotor structure, comprising:

[0009] Rotor core;

[0010] A plurality of mother permanent magnets, each of which is arranged on the outer periphery of the rotor core and spaced apart along the circumferential direction of the rotor core;

[0011] A plurality of retainers, each of which is provided on the rotor core and arranged at intervals along the circumference of the rotor core; the retainers are non-magnetic insulating structural members,

[0012] It is characterized in that each of the mother permanent magnets includes two sub-permanent magnets, and the multiple mother permanent magnets are arranged in one-to-one correspondence with the multiple retaining frames, each of the retaining frames is located between the two sub-permanent magnets of the corresponding mother permanent magnet and the two sub-permanent magnets are fixedly installed on the rotor core; the two sub-permanent magnets of the same mother permanent magnet have the same magnetic properties, and the two sub-permanent magnets located between adjacent retaining frames have opposite magnetic properties.

[0013] As a preferred technical solution for the above-mentioned rotor structure, the outer peripheral wall of the rotor core is provided with mounting grooves corresponding one to one with the retaining frame, one end of the retaining frame and one of the bottom walls of the mounting groove are provided with embedding protrusions, and the other end is provided with an embedding groove, and the embedding protrusion is embedded in the embedding groove; the other end of the retaining frame crimps the two sub-permanent magnets corresponding to the mother permanent magnet to the bottom wall of the mounting groove.

[0014] As a preferred technical solution for the above-mentioned rotor structure, the outer peripheral wall of the rotor core is provided with a mounting groove corresponding to the retaining frame one by one, one of the one end of the retaining frame and the bottom wall of the mounting groove is provided with an embedding protrusion, and the other is provided with an embedding groove, and the embedding protrusion is embedded in the embedding groove; the other end of the retaining frame crimps the two permanent magnets adjacent to the retaining frame and respectively located on both sides of the retaining frame to the bottom wall of the mounting groove.

[0015] As a preferred technical solution of the above rotor structure, the embedding groove is a dovetail groove opened on the bottom wall of the installation groove, and the embedding protrusion is a dovetail block provided at one end of the retaining frame.

[0016] As a preferred technical solution for the above-mentioned rotor structure, the retaining frame includes a limiting portion abutting against the outer peripheral wall of the mother permanent magnet, and a connecting portion extending radially along the rotor core, one end of the connecting portion is connected to the limiting portion to form a T-shaped structure, and the other end of the connecting portion is connected to the embedded protrusion; the connecting portion is located between the two sub-permanent magnets of the corresponding mother permanent magnet.

[0017] As a preferred technical solution of the above rotor structure, the sub-permanent magnet has two first side walls that are arranged opposite to each other and parallel to each other along a first direction, and the first side walls are parallel to the extending direction of the connecting portion and perpendicular to the first direction;

[0018] Along the first direction, the maximum length of the limiting portion along the first direction is 2L, the distance between the two first side walls is P, and 0.5P≤L≤P.

[0019] As a preferred technical solution of the above rotor structure, the P of the two sub-permanent magnets of the same mother permanent magnet is different.

[0020] As a preferred technical solution to the above rotor structure, the maximum length of the limiting portion extending out of the mother permanent magnet along the extension direction of the connecting portion is H, the length of the connecting portion along the first direction is W, and 2H≤W≤10H.

[0021] As a preferred technical solution of the above rotor structure, one end of the sub-permanent magnet extends out of the mounting slot along the radial direction of the rotor core.

[0022] As a preferred technical solution of the above rotor structure, the outer peripheral wall of the retaining frame is an arc-shaped surface, and the outer peripheral wall of the retaining frame is smoothly connected to the outer peripheral walls of the two sub-permanent magnets of the corresponding mother permanent magnet.

[0023] In order to achieve the above-mentioned purpose, the utility model also provides a permanent magnet synchronous motor, including a stator structure and a rotor structure as described in any of the above schemes, wherein the stator structure is provided with a center hole, and the rotor structure is rotatably inserted into the center hole.

[0024] Beneficial effects of the utility model: the rotor structure and permanent magnet synchronous motor provided by the utility model use a retaining frame to fix two permanent magnets connected to the retaining frame and respectively located on both sides of the retaining frame to the rotor core through the retaining frame, and the retaining frame is embedded in the rotor core, so that the retaining frame can be used to prevent the permanent magnets from flying away from the rotor core under the action of centrifugal force, thereby improving the stability between the permanent magnets and the rotor core; the stainless steel sheath can be eliminated, which can avoid the increase of eddy current loss during the operation of the permanent magnet synchronous motor due to the provision of the stainless steel sheath, reduce the risk of high-temperature demagnetization of the permanent magnet, and improve the motor efficiency.

[0025] Since the two sub-permanent magnets of the same mother permanent magnet have the same magnetism, and the two mother permanent magnets located between adjacent retainers have opposite magnetism, when the permanent magnet synchronous motor is working, the magnetic flux lines between the two sub-permanent magnets of the same mother permanent magnet are sparse, and the magnetic flux lines between the two sub-permanent magnets between the two retainers are dense. The retainer is set between the two sub-permanent magnets of the same mother permanent magnet, and there is no need to set the retainer between the two mother permanent magnets. This effectively solves the problem of reducing the magnetic flux saturation of the rotor core due to the dovetail groove for installing the retainer between the two mother permanent magnets in the prior art, and reduces the magnetic leakage rate of the rotor structure. Compared with the prior art, the no-load back electromotive force of the permanent magnet synchronous motor using the rotor structure of the utility model is improved, and the utilization rate of the mother permanent magnet is improved.

[0026] Moreover, the pole arc coefficient of the permanent magnet synchronous motor can be determined by the ratio of the arc length spanned by the permanent magnet to the pole pitch. A mother permanent magnet is split into two sub-permanent magnets, and a retaining frame is set between the two sub-permanent magnets. When the arc length occupied by a mother permanent magnet along the circumference of the rotor core remains unchanged, a mother retaining frame is set between the two sub-permanent magnets. This can reduce the sum of the arc lengths of the two sub-permanent magnets, and then reduce the pole arc coefficient, thereby reducing the harmonic content of the motor back electromotive force, making the no-load back electromotive force more sinusoidal, and thus reducing the motor vibration noise.

[0027] In addition, the rotor structure has the advantages of simple structure, simple installation method of permanent magnets, low manufacturing difficulty and low processing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0029] Figure 1 It is a schematic diagram of the axial end surface of the rotor structure provided by an embodiment of the utility model;

[0030] Figure 2 This is a schematic diagram of the magnetic field distribution of the rotor structure of a permanent magnet synchronous motor using the rotor structure provided by an embodiment of the utility model when the motor is working;

[0031] Figure 3 It is a schematic diagram of the magnetic field distribution of the rotor structure when the permanent magnet synchronous motor with the existing rotor structure is working;

[0032] Figure 4 It is a schematic diagram of the back electromotive force change of a permanent magnet synchronous motor when running at no load when the rotor structure of the prior art and the rotor structure provided by the embodiment of the utility model are adopted;

[0033] Figure 5 It is a partial schematic diagram of the rotor structure provided by an embodiment of the utility model;

[0034] Figure 6 It is a structural schematic diagram of a retainer in a rotor structure provided by an embodiment of the utility model;

[0035] Figure 7 It is a schematic diagram of the axial end surface of the rotor core in the rotor structure provided in an embodiment of the utility model.

[0036] In the figure:

[0037] 1. rotor core; 11. mounting groove; 12. embedding groove; 13. limit block;

[0038] 2. retaining frame; 21. embedded convex portion; 22. connecting portion; 23. limiting portion;

[0039] 3. mother permanent magnet; 30. daughter permanent magnet; 31. first side wall;

[0040] 100. Rotor structure. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0042] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0044] In the description of this embodiment, the terms "upper", "lower", "right", etc., are based on the directions or positions shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0045] like Figure 1As shown, an embodiment of the utility model provides a rotor structure and a permanent magnet synchronous motor, wherein the permanent magnet synchronous motor comprises a rotor structure 100 and a stator structure, wherein a center hole is provided on the stator structure, and the rotor structure 100 is rotatably inserted through the center hole, and an air gap is formed between the rotor structure 100 and the inner circumferential wall of the center hole.

[0046] The rotor structure 100 includes a rotor core 1, a plurality of mother permanent magnets 3 and a plurality of retainers 2, wherein the plurality of mother permanent magnets 3 are arranged on the outer periphery of the rotor core 1 and are arranged at intervals along the circumference of the rotor core 1; the plurality of retainers 2 are provided on the rotor core 1 and are arranged at intervals along the circumference of the rotor core 1, the retainer 2 is a non-magnetic insulating structural member, each mother permanent magnet 3 includes two sub-permanent magnets 30, the plurality of mother permanent magnets 3 are arranged in one-to-one correspondence with the plurality of retainers 2, each retainer 2 is located between the two sub-permanent magnets 30 of the corresponding mother permanent magnet 3 and the two sub-permanent magnets 30 are fixedly mounted on the rotor core 1. The two sub-permanent magnets 30 of the same mother permanent magnet 3 have the same magnetic properties, and the two sub-permanent magnets 3 located between adjacent retainers 2 have opposite magnetic properties.

[0047] The two sub-permanent magnets 30 corresponding to the mother permanent magnet 3 of the retaining frame 2 are fixedly installed on the rotor core 1. The retaining frame 2 can be used to prevent the mother permanent magnet 3 from flying away from the rotor core 1 under the action of centrifugal force, thereby improving the stability between the mother permanent magnet 3 and the rotor core 1; the stainless steel sheath can be eliminated, which can avoid the increase of eddy current loss during the operation of the permanent magnet synchronous motor due to the setting of the stainless steel sheath, reduce the risk of high-temperature demagnetization of the mother permanent magnet 3, and improve the motor efficiency.

[0048] like Figure 2 and Figure 3 As shown, since the two sub-permanent magnets 30 of the same mother permanent magnet 3 have the same magnetic properties, and the two mother permanent magnets 3 located between adjacent retaining frames 2 have opposite magnetic properties, when the permanent magnet synchronous motor is working, the magnetic flux lines between the two sub-permanent magnets 30 of the same mother permanent magnet 3 are sparse, and the magnetic flux lines between the two sub-permanent magnets 30 between the two retaining frames 2 are dense. The non-magnetic and insulating retaining frame 2 is set between the two sub-permanent magnets 30 of the same mother permanent magnet 3, and there is no need to set the retaining frame 2 between the two mother permanent magnets 3. This greatly reduces the influence of the setting of the retaining frame 2 on the magnetic flux of the mother permanent magnet 3, and effectively solves the problem of reducing the magnetic flux saturation of the rotor core due to the opening of a dovetail groove for installing the retaining frame between the two mother permanent magnets in the prior art, thereby reducing the magnetic leakage rate of the rotor structure 100.

[0049] like Figure 4As shown in the figure, when the existing rotor structure is applied to the permanent magnet synchronous motor, the no-load back electromotive force amplitude of UVW is 5.01V, and when the rotor structure provided in this embodiment is applied to the permanent magnet synchronous motor, the no-load back electromotive force amplitude of U′V′W′ is 5.32V. Compared with the prior art, the no-load back electromotive force of the permanent magnet synchronous motor using the rotor structure provided in the embodiment of the utility model is improved, and the utilization rate of the mother permanent magnet 3 is improved. Moreover, the pole arc coefficient of the permanent magnet synchronous motor can be determined by the ratio of the arc length spanned by the permanent magnet to the pole pitch. A mother permanent magnet 3 is split into two sub-permanent magnets 30, and a retainer 2 is arranged between the two sub-permanent magnets 30. When the arc length of the rotor core 1 occupied by a mother permanent magnet 3 along the circumference of the rotor core 1 remains unchanged, a mother retainer 2 is arranged between the two sub-permanent magnets 30, which can reduce the sum of the arc lengths of the two sub-permanent magnets 30, and then reduce the pole arc coefficient, thereby reducing the harmonic content of the motor back electromotive force, and can make the sinusoidality of the no-load back electromotive force higher, thereby reducing the vibration noise of the motor.

[0050] In addition, the rotor structure 100 has the advantages of simple structure, simple installation method of the mother permanent magnet 3, low manufacturing difficulty and low processing cost.

[0051] Specifically, the outer peripheral wall of the rotor core 1 is provided with a mounting groove 11 corresponding to the retainer 2 one by one, and an embedding protrusion 21 is provided on one end of the retainer 2 and the bottom wall of the mounting groove 11, and the other end is provided with an embedding groove 12, and the embedding protrusion 21 is embedded in the embedding groove 12; the other end of the retainer 2 presses the two sub-permanent magnets 30 of the corresponding mother permanent magnet 3 to the bottom wall of the mounting groove 11. Exemplarily, the embedding groove 12 is provided on the bottom wall of the mounting groove 11, and the embedding protrusion 21 is provided on one end of the retainer 2. In other embodiments, the embedding groove 12 can also be provided on one end of the retainer 2, and the embedding protrusion 21 can be convexly provided on the bottom wall of the mounting groove 11.

[0052] Optionally, the embedding groove 12 is a dovetail groove, and the embedding protrusion 21 is a dovetail block. By embedding the dovetail block in the dovetail groove, the connection stability between the retaining frame 2 and the rotor core 1 can be improved.

[0053] In order to fix the two sub-permanent magnets 30 of the mother permanent magnet 3 to the rotor core 1 through the retaining frame 2, in some embodiments, the retaining frame 2 includes a limiting portion 23 abutting against the outer peripheral wall of the mother permanent magnet 3, and a connecting portion 22 extending radially along the rotor core 1, one end of the connecting portion 22 is connected to the limiting portion 23 to form a T-shaped structure, and the other end of the connecting portion 22 is connected to the embedded protrusion 21; the connecting portion 22 is located between the two sub-permanent magnets 30 of the corresponding mother permanent magnet 3.

[0054] Specifically, the bottom wall of the installation groove 11 is perpendicular to the extending direction of the connecting portion 22 , the length of the connecting portion 22 along the extending direction is L1 , the maximum width of the sub-permanent magnet 30 along the extending direction of the connecting portion 22 is L2 , and L1 = L2 .

[0055] In some embodiments, the sub-permanent magnet 30 has two first side walls 31 arranged opposite to each other and parallel to each other along the first direction, the first side walls 31 are parallel to the extension direction of the connecting portion 22 and perpendicular to the first direction; the maximum length of the limiting portion 23 extending out of the connecting portion 22 along the first direction is L, and the spacing between the two first side walls 31 is P, 0.5P≤L≤P. By limiting 0.5P≤L≤P, the limiting effect of the limiting portion 23 on the two sub-permanent magnets 30 can be improved, thereby improving the stability of the mother permanent magnet 3 after the two sub-permanent magnets 30 corresponding to the mother permanent magnet 3 are fixedly installed on the rotor core 1 using the retaining frame 2. In addition, since the sub-permanent magnet 30 has two first side walls 31 that are arranged opposite to each other and parallel along the first direction, the first side wall 31 facing away from the retaining frame 2 abuts against the slot side wall of the mounting slot 11, that is, the opposite side walls of the mounting slot 11 are spaced apart and arranged in parallel along the first direction, so that a dovetail-shaped limit block 13 is formed between two adjacent mounting slots 11, thereby improving the connection stability between the mother permanent magnet 3 and the rotor core 1.

[0056] It should be noted that the value of L can be any one of 0.5P, 0.55P, 0.6P, 0.65P, 0.7P, 0.75P, 0.8P, 0.85P, 0.9P, 0.95P and P. Exemplarily, L=0.5P, and the outer peripheral wall of the limit block 13 is a plane.

[0057] In some embodiments, the P of the two sub-permanent magnets 30 of the same mother permanent magnet 3 is different. In this way, it is possible to reduce the pole arc coefficient of the mother permanent magnet 3 by reducing the P of any sub-permanent magnet 30 of the same mother permanent magnet 3, so as to reduce the harmonic content of the motor back electromotive force, and improve the flexibility of the design of the mother permanent magnet 3. It should be noted that the proportional relationship of the P of the two sub-permanent magnets 30 of the same mother permanent magnet 3 is determined according to the number of slot poles of the stator structure, and is no longer specifically limited here. In some other embodiments, the two sub-permanent magnets 30 of the mother permanent magnet 3 corresponding to the retaining frame 2 can also be arranged symmetrically about the retaining frame 2. Specifically, the retaining frame 2 is symmetrically arranged about the preset plane 4, and the two sub-permanent magnets 30 of the mother permanent magnet 3 corresponding to the retaining frame 2 are symmetrically arranged about the preset plane 4. In other words, the P of the two sub-permanent magnets 30 of the same mother permanent magnet 3 is the same, and the preset plane 4 is perpendicular to the first direction.

[0058] In some embodiments, the maximum length of the limiting portion 23 extending from the mother permanent magnet 3 along the extension direction of the connecting portion 22 is H, the length of the connecting portion 22 along the first direction is W, and 2H≤W≤10H. In this way, the structural strength of the retaining frame 2 can be improved, so that the limiting portion 23 has sufficient structural strength, and the limiting portion 23 is prevented from being deformed and causing the mother permanent magnet 3 to be separated from the mounting groove 11.

[0059] It should be noted that the value of W can be any one of 2H, 2.5H, 3H, 3.5H, 4H, 4.5H, 5H, 5.5H, 6H, 6.5H, 7H, 7.5H, 8H, 8.5H, 9H and 10H. For example, 1mm≤W≤2mm, 0.2mm≤H≤0.5mm.

[0060] In some embodiments, one end of the sub-permanent magnet 30 extends out of the mounting slot 11 along the radial direction of the rotor core 1 .

[0061] In some embodiments, the outer peripheral wall of the retaining frame 2 is an arc-shaped surface, and the outer peripheral wall of the retaining frame 2 is smoothly connected to the outer peripheral wall of the two sub-permanent magnets 30 of the corresponding mother permanent magnet 3. In this way, the sub-permanent magnets 30 on both sides of the retaining frame 2 and the retaining frame 2 can form a bread-shaped structure, making the surface of the rotor structure 100 smoother and reducing wind friction loss. In addition, the above is only a preferred embodiment of the utility model and the technical principles used. Those skilled in the art will understand that the utility model is not limited to the specific embodiments here, and that various obvious changes, readjustments and substitutions can be made to those skilled in the art without departing from the scope of protection of the utility model. Therefore, although the utility model is described in more detail through the above embodiments, the utility model is not limited to the above embodiments, and may also include more other equivalent embodiments without departing from the concept of the utility model, and the scope of the utility model is determined by the scope of the attached claims.

Claims

1. A rotor structure, comprising: A rotor core (1); A plurality of mother permanent magnets (3), wherein the plurality of mother permanent magnets (3) are arranged on the outer periphery of the rotor core (1) and are arranged at intervals along the circumferential direction of the rotor core (1); A plurality of retaining frames (2), each of which is provided on the rotor core (1) and is arranged at intervals along the circumference of the rotor core (1); the retaining frames (2) are non-magnetic insulating structural members. The invention is characterized in that each of the mother permanent magnets (3) comprises two sub-permanent magnets (30), a plurality of the mother permanent magnets (3) are arranged in one-to-one correspondence with a plurality of the retaining frames (2), each of the retaining frames (2) is located between the two sub-permanent magnets (30) of the corresponding mother permanent magnet (3) and the two sub-permanent magnets (30) are fixedly mounted on the rotor core (1); the two sub-permanent magnets (30) of the same mother permanent magnet (3) have the same magnetic properties, and the two sub-permanent magnets (30) located between adjacent retaining frames (2) have opposite magnetic properties.

2. The rotor structure according to claim 1, characterized in that: The outer peripheral wall of the rotor core (1) is provided with a mounting groove (11) corresponding to the retaining frame (2) one by one, one of the ends of the retaining frame (2) and the bottom wall of the mounting groove (11) is provided with an embedding protrusion (21), and the other end is provided with an embedding groove (12), and the embedding protrusion (21) is embedded in the embedding groove (12); the other end of the retaining frame (2) presses the two sub-permanent magnets (30) corresponding to the mother permanent magnet (3) to the bottom wall of the mounting groove (11).

3. The rotor structure according to claim 2, characterized in that: The embedding groove (12) is a dovetail groove provided on the bottom wall of the installation groove (11), and the embedding protrusion (21) is a dovetail block provided on one end of the retaining frame (2).

4. The rotor structure according to claim 2, characterized in that: The retaining frame (2) comprises a limiting portion (23) abutting against the outer peripheral wall of the mother permanent magnet (3), and a connecting portion (22) extending radially along the rotor core (1), one end of the connecting portion (22) is connected to the limiting portion (23) to form a T-shaped structure, and the other end of the connecting portion (22) is connected to the embedded protrusion (21); the connecting portion (22) is located between the two sub-permanent magnets (30) of the corresponding mother permanent magnet (3).

5. The rotor structure according to claim 4, characterized in that: The sub-permanent magnet (30) has two first side walls (31) that are arranged opposite to each other and are parallel along a first direction, and the first side walls (31) are parallel to the extension direction of the connecting portion (22) and perpendicular to the first direction; The maximum length of the limiting portion (23) extending from the connecting portion (22) along the first direction is L, the spacing between the two first side walls (31) is P, and 0.5P≤L≤P.

6. The rotor structure according to claim 5, characterized in that: The P of the two sub-permanent magnets (30) of the same mother permanent magnet (3) is different.

7. The rotor structure according to claim 5, characterized in that: The maximum length of the limiting portion (23) extending out of the mother permanent magnet (3) along the extension direction of the connecting portion (22) is H, the length of the connecting portion (22) along the first direction is W, and 2H≤W≤10H.

8. The rotor structure according to claim 2, characterized in that: One end of the sub-permanent magnet (30) extends out of the mounting slot (11) along the radial direction of the rotor core (1).

9. The rotor structure according to claim 2, characterized in that: The outer peripheral wall of the retaining frame (2) is an arc-shaped surface, and the outer peripheral wall of the retaining frame (2) is smoothly connected to the outer peripheral walls of the two sub-permanent magnets (30) of the corresponding mother permanent magnet (3).

10. A permanent magnet synchronous motor, characterized in that: It comprises a stator structure and a rotor structure (100) as claimed in any one of claims 1 to 9, wherein the stator structure is provided with a center hole, the rotor structure (100) is rotatably inserted into the center hole, and an air gap is formed between the rotor structure (100) and the inner peripheral wall of the center hole.

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