Rotor structure and motor

Abstract

The invention provides a rotor structure and a motor. The rotor structure comprises a permanent magnet (1) and a rotor iron core (2), the permanent magnet (1) comprises covering parts (11) and embedding parts (12), the rotor iron core (2) is provided with mounting grooves (21), the covering parts (11) cover the axial end parts of the rotor iron core (2), the embedding parts (12) are embedded in the mounting grooves (21), the permanent magnet (1) is of an integral structure, the covering parts (11) are located at the two axial ends of the embedding parts (12), and the two covering parts (11) and the embedding parts (12) form a cage type structure. According to the rotor structure, the magnetic gathering effect of the motor can be effectively improved, and the top leakage flux of the permanent magnet is weakened.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a rotor structure and a motor. Background Art

[0002] With the improvement of motor energy efficiency standards, higher requirements are placed on the energy efficiency level of motors. For permanent magnet motors, the efficiency and high torque density of the motors need to be further improved.

[0003] At present, there are two technical means to improve motor efficiency and torque density. One is to embed permanent magnets to obtain a larger air gap flux and a larger magnetic flux. However, due to the fixed rotor magnetic circuit structure, the energy efficiency improvement is limited. Another means is to use the rotor structure to increase the motor salient pole ratio and increase the motor's reluctance torque to compensate for the lack of permanent magnet torque. Its efficiency can be comparable to that of a permanent magnet motor, but it usually requires a larger rotor volume, which will make the motor torque density inferior to that of a permanent magnet motor.

[0004] Therefore, for current motors, how to further achieve higher efficiency and higher torque density is an urgent problem to be solved. Summary of the invention

[0005] The main purpose of the present invention is to provide a rotor structure and a motor, which can effectively improve the magnetic field concentration effect of the motor and weaken the top leakage flux of the permanent magnet.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a rotor structure is provided, including a permanent magnet and a rotor core, the permanent magnet including a covering portion and an embedded portion, the rotor core having a mounting groove, the covering portion covering the axial end portion of the rotor core, the embedded portion embedded in the mounting groove, the permanent magnet being an integral structure, the covering portion being located at the axial ends of the embedded portion, and the two covering portions and the embedded portion forming a cage-type structure.

[0007] Furthermore, the outer peripheral side of the rotor core is a fully open slot structure, and the open slots of the fully open slot structure are arranged at intervals along the circumferential direction.

[0008] Furthermore, the permanent magnet is an injection-molded permanent magnet, and the rotor core is formed by laminating silicon steel sheets.

[0009] Furthermore, the permanent magnet includes a first magnetizing part and a second magnetizing part, the second magnetizing part includes an embedded part and a partial covering part, the partial covering part is located at both axial ends of the embedded part and extends axially from one end of the covering part to the other end, and the partial covering part is an extension section of the embedded part in the covering part; the parts on both circumferential sides of the second magnetizing part in the covering part form the first magnetizing part.

[0010] Furthermore, the first magnetizing portion and the second magnetizing portion have different magnetizing methods.

[0011] Further, the first magnetizing portion is magnetized along the axial direction of the rotor, and the second magnetizing portion is magnetized along the radial direction of the rotor.

[0012] Furthermore, the polarity of the first magnetizing portion on one side close to the rotor core is the first polarity, and the polarities of the two second magnetizing portions on both sides adjacent to the first magnetizing portion on one side close to the rotor core are the first polarity.

[0013] Furthermore, the outer peripheral wall of the rotor core includes a plurality of arc surfaces arranged at intervals, and along the circumferential direction, the distance between the arc surfaces and the central axis of the rotor core decreases from the middle to both ends.

[0014] Further, along the axial direction of the rotor, there is no gap between the cover and the rotor core.

[0015] Furthermore, the width of the open slot of the fully open slot structure on the outer peripheral side of the rotor core is x, and the height of the covering portion along the axial direction of the rotor is y, then 0.5≤y / x≤1.9.

[0016] Furthermore, the permanent magnet is integrally embedded and coated on the rotor core by injection molding process.

[0017] According to another aspect of the present invention, a motor is provided, comprising a stator structure and a rotor structure, wherein the rotor structure is the above-mentioned rotor structure.

[0018] Applying the technical solution of the present invention, the rotor structure includes a permanent magnet and a rotor core, the permanent magnet includes a covering portion and an embedded portion, the rotor core has a mounting groove, the covering portion covers the axial end of the rotor core, the embedded portion is embedded in the mounting groove, the permanent magnet is an integral structure, the covering portion is located at the axial ends of the embedded portion, and the two covering portions and the embedded portion form a cage structure.

[0019] The permanent magnet of this rotor structure includes a covering part and an embedded part. The magnetic lines of force of the covering part and the embedded part gather on the rotor core from different directions and then enter the air gap to form a main magnetic flux, which can enhance the magnetic field concentration effect of the motor. The permanent magnet is formed into a cage-type structure by the covering part and the embedded part, which is integrally covered and embedded on the rotor core, so that there is no need to set a permanent magnet limit part on the rotor core. The outer peripheral side of the rotor core is set to a fully open slot structure, which can weaken the top leakage flux of the permanent magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 An exploded structural diagram showing a rotor structure of an embodiment of the present invention;

[0022] Figure 2 A three-dimensional structural diagram showing a rotor structure of an embodiment of the present invention;

[0023] Figure 3 A three-dimensional structural diagram of a rotor core according to an embodiment of the present invention is shown;

[0024] Figure 4 A schematic diagram of the structure of a rotor core according to an embodiment of the present invention is shown from above;

[0025] Figure 5 A schematic diagram of the three-dimensional structure of a permanent magnet according to an embodiment of the present invention is shown;

[0026] Figure 6 A schematic diagram of the structure of a permanent magnet according to an embodiment of the present invention is shown from above;

[0027] Figure 7 Shows Figure 6 AA section view;

[0028] Figure 8 Shows Figure 6 BB section view;

[0029] Fig. 9 A comparison diagram of magnetic concentration coefficients of a motor according to an embodiment of the present invention and a motor according to related art is shown;

[0030] Fig.10 A comparison diagram of the permanent magnet top leakage flux of the motor of the embodiment of the present invention and the motor of the related art is shown;

[0031] Fig.11 A comparison diagram of no-load flux linkage between a motor according to an embodiment of the present invention and a motor in the related art is shown;

[0032] Fig.12 A comparison diagram of air gap flux density between a motor according to an embodiment of the present invention and a motor according to a related art is shown; and

[0033] Fig.13 A torque-current characteristic comparison diagram of the motor according to the embodiment of the present invention and the motor according to the related art is shown.

[0034] The above drawings include the following reference numerals:

[0035] 1. Permanent magnet; 11. Covering part; 12. Embedding part; 13. First magnetizing part; 14. Second magnetizing part; 2. Rotor core; 21. Mounting groove. DETAILED DESCRIPTION

[0036] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] See also Figures 1 to 8 As shown, according to an embodiment of the present invention, the rotor structure includes a permanent magnet 1 and a rotor core 2, the permanent magnet 1 includes a covering portion 11 and an embedding portion 12, and the rotor core 2 has a mounting groove 21. The covering portion 11 covers the axial end of the rotor core 2, and the embedding portion 12 is embedded in the mounting groove 21. The permanent magnet 1 is an integral structure, the covering portion 11 is located at both axial ends of the embedding portion 12, and the two covering portions 11 and the embedding portion 12 form a cage structure. The outer peripheral side of the rotor core 2 is a fully open slot structure, and the fully open slots are arranged at intervals along the circumferential direction.

[0038] The permanent magnet 1 of the rotor structure includes a covering portion 11 and an embedded portion 12. The magnetic lines of force of the covering portion 11 and the embedded portion 12 gather on the rotor core 2 from different directions and then enter the air gap to form a main magnetic flux, which can enhance the magnetic field concentration effect of the motor. The permanent magnet 1 is formed into a cage-type structure by the covering portion 11 and the embedded portion 12, which is integrally covered and embedded on the rotor core 2, so that there is no need to set a permanent magnet limit portion on the rotor core 2. The outer peripheral side of the rotor core 2 is set as a fully open slot structure, which can weaken the top leakage flux of the permanent magnet.

[0039] In one embodiment, the permanent magnet 1 is an injection molded permanent magnet, and the rotor core 2 is formed by laminating silicon steel sheets. The use of injection molded magnets for permanent magnets can reduce rotor saturation and iron loss on the one hand; on the other hand, injection molded magnets have a higher degree of freedom in shape, which can reduce the difficulty of manufacturing the permanent magnet 1. The rotor core 2 is a path carrier for the magnetic flux of the permanent magnet 1, and has the function of clearing and guiding the magnetic flux. The rotor core 2 is formed by laminating silicon steel sheets and has better magnetic conductivity.

[0040] In one embodiment, the permanent magnet 1 is injection-molded ferrite or injection-molded neodymium iron boron. The permanent magnet 1 may also be injection-molded magnetic steel of other material types.

[0041] In one embodiment, the permanent magnet 1 includes a first magnetizing portion 13 and a second magnetizing portion 14. The second magnetizing portion 14 includes an embedded portion 12 and a partial covering portion 11. The partial covering portion 11 is located at both axial ends of the embedded portion 12 and extends axially from one end of the covering portion 11 to the other end. The partial covering portion 11 is an extension section of the embedded portion 12 in the covering portion 11. The portions on both circumferential sides of the second magnetizing portion 14 in the covering portion 11 form the first magnetizing portion 13.

[0042] In this embodiment, the permanent magnet 1 includes a first magnetizing portion 13 and a second magnetizing portion 14, the second magnetizing portion 14 includes an embedded portion 12 and a portion penetrating the covering portion 11 along the axial direction of the embedded portion 12; the portions on both sides of the second magnetizing portion 14 in the covering portion 11 in the circumferential direction are the first magnetizing portion 13. The covering portion 11 in this embodiment is divided into two parts, one part is a part located at the axial end of the embedded portion 12 and located in the extension direction of the embedded portion 12, and the other part is a part located outside the extension direction of the embedded portion 12, wherein the part located in the extension direction of the embedded portion 12 and the embedded portion 12 together form the second magnetizing portion 14, and the part of the covering portion 11 located outside the extension direction of the embedded portion 12 forms the first magnetizing portion 13, and the magnetizing directions of the first magnetizing portion 13 and the second magnetizing portion 14 are designed in accordance with the positions of the covering portion 11 and the embedded portion 12, and the magnetic lines of force of the permanent magnets at different positions squeeze each other after entering the rotor core from different directions, making it more likely to become the main magnetic flux and having a better magnetic concentration effect.

[0043] In one embodiment, the first magnetizing part 13 and the second magnetizing part 14 have different magnetizing modes. Preferably, the first magnetizing part 13 is magnetized along the axial direction of the rotor, and the second magnetizing part 14 is magnetized along the radial direction of the rotor. Such magnetizing directions are set corresponding to the relative positions of the first magnetizing part 13, the second magnetizing part 14 and the rotor core 2.

[0044] In one embodiment, the second magnetizing portion 14 is magnetized tangentially, and the first magnetizing portion 13 is magnetized axially. The second magnetizing portion 14 with a larger axial height is set to be magnetized tangentially, and the first magnetizing portion 13 set at the axial end of the rotor core 2 is magnetized axially. This can achieve the continuity of the magnetic flux of the first magnetizing portion 13 and the second magnetizing portion 14, so that the two can more effectively provide magnetic flux for the motor together, effectively increasing the motor output.

[0045] In one embodiment, the polarity of the first magnetizing portion 13 on the side close to the rotor core 2 is the first polarity, and the polarities of the two second magnetizing portions 14 on the two sides adjacent to the first magnetizing portion 13 on the side close to the rotor core 2 are the first polarity. The first magnetizing portion 13 is axially magnetized, and the second magnetizing portion 14 is tangentially magnetized. The magnetic lines of force of the first magnetizing portion 13 enter the rotor core 2 with the second magnetizing portion 14 as the magnetic path, and the magnetic lines of force generated by the second magnetizing portion 14 are concentrated and enter the air gap and the stator through the rotor core 2, which can greatly improve the magnetic concentration effect of the motor, and improve the torque density and efficiency of the motor.

[0046] In one embodiment, the outer peripheral wall of the rotor core 2 includes a plurality of arc surfaces arranged at intervals, and along the circumferential direction, the distance between the arc surface and the central axis of the rotor core 2 decreases from the middle to the two ends. In this embodiment, the rotor core 2 forms a fully open slot structure, and the outer peripheral structure of the rotor core 2 is not a full circle, but a plurality of arc segments arranged at intervals, and the middle of each arc segment protrudes outward along the radial direction to form an arc structure that is misaligned with the center of the outer circle of the rotor, which can improve the air gap magnetic flux between the stator and the rotor, is more conducive to forming a sine curve, and improves the working performance of the motor.

[0047] In one embodiment, a support protrusion protruding radially outward is provided on the radially inner side wall of the mounting groove 21 of the rotor core 2, and the top shape of the support protrusion matches the radially inner side wall of the embedding portion 12 to form surface contact.

[0048] In one embodiment, the permanent magnet 1 is a magnetic flux source, and except for the rotor core 2, no other magnetic conductive components are provided in the rotor structure.

[0049] In one embodiment, along the axial direction of the rotor, there is no gap between the cover 11 and the rotor core 2. In this embodiment, a polar region of the cover 11 generates magnetic flux, and a polar region of the rotor core 2 at a corresponding position is a magnetic path of the magnetic flux. No gap between the two can shorten the magnetic path as much as possible and reduce magnetic loss.

[0050] In one embodiment, the width of the opening slot of the fully open slot structure on the outer peripheral side of the rotor core 2 is x, and the height of the covering portion 11 along the axial direction of the rotor is y, then 0.5≤y / x≤1.9. By limiting the maximum value of y / x, on the one hand, the oversaturation of the rotor core 2 caused by the magnetic flux of the covering portion 11 can be avoided, and on the other hand, a certain width of the fully open slot of the rotor core 2 can be guaranteed to weaken the top leakage magnetic flux of the permanent magnet 1; by limiting the minimum value of y / x, on the one hand, the slot width of the fully open slot of the rotor core 2 can be limited to be too large, which leads to insufficient mechanical strength of the rotor core 2, and on the other hand, the poor anti-demagnetization performance caused by the small thickness of the covering portion 11 can be avoided.

[0051] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 2, the inner diameter of the permanent magnet 1 is not less than the inner diameter of the rotor core 2. The inner hole of the rotor core 2 needs to be equipped with a rotating shaft, and the above-mentioned size relationship can make way for the assembly of the rotating shaft on the one hand; on the other hand, without affecting the assembly of the rotating shaft, the inner hole of the permanent magnet 1 can be filled with plastic packaging material or other materials to enhance the strength of the rotor.

[0052] In one embodiment, the inner diameter of the permanent magnet 1 is equal to the inner diameter of the rotor core 2 .

[0053] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 2 , the maximum value of the outer diameter of the permanent magnet 1 is not greater than the maximum value of the outer diameter of the rotor core 2 .

[0054] In one embodiment, the maximum value of the outer diameter of the permanent magnet 1 is equal to the maximum value of the outer diameter of the rotor core 2 .

[0055] For the motor, the stator structure is sleeved on the outer side of the rotor structure, and an air gap is provided between the rotor structure and the stator structure. This setting can make way for the assembly of the stator structure.

[0056] In one embodiment, the permanent magnet 1 is produced by injection molding process, and is integrally embedded in and coated on the rotor core 2 .

[0057] See also Fig. 9 As shown, compared with the motor in the related art, the magnetic concentration coefficient of the motor using the rotor structure of the embodiment of the present invention is increased by more than 60%, and the magnetic concentration performance is significantly improved.

[0058] See also Fig.10 As shown, compared with the motor in the related art, the leakage flux at the top of the permanent magnet of the motor adopting the rotor structure of the embodiment of the present invention is weakened by more than 30%.

[0059] See also Fig.11 As shown, compared with the motor in the related art, the no-load flux of the motor using the rotor structure of the embodiment of the present invention is increased by more than 50%, which effectively increases the no-load flux and improves the motor performance.

[0060] See also Fig.12 As shown, compared with the motor in the related art, the air gap flux density of the motor using the rotor structure of the embodiment of the present invention is increased by more than 60%, which effectively increases the air gap flux density, improves the motor torque density, and increases the motor output.

[0061] See also Fig.13 As shown, compared with the motors of the related art, the torque multiple of the motor adopting the rotor structure of the embodiment of the present invention becomes increasingly advantageous as the current increases, thereby achieving a larger torque multiple, improving the motor torque density, and increasing the motor output.

[0062] According to an embodiment of the present invention, the motor includes a stator structure and a rotor structure, and the rotor structure is the above-mentioned rotor structure.

[0063] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0064] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A rotor structure, characterized in that: The invention comprises a permanent magnet (1) and a rotor core (2), wherein the permanent magnet (1) comprises a covering portion (11) and an embedding portion (12), the rotor core (2) has a mounting groove (21), the covering portion (11) covers the axial end of the rotor core (2), and the embedding portion (12) is embedded in the mounting groove (21), the permanent magnet (1) is an integral structure, the covering portion (11) is located at the axial ends of the embedding portion (12), and the two covering portions (11) and the embedding portion (12) form a cage-type structure.

2. The rotor structure according to claim 1, characterized in that: The outer peripheral side of the rotor core (2) is a fully open slot structure, and the open slots of the fully open slot structure are arranged at intervals along the circumferential direction.

3. The rotor structure according to claim 1, characterized in that: The permanent magnet (1) is an injection-molded permanent magnet, and the rotor core (2) is formed by laminating silicon steel sheets.

4. The rotor structure according to claim 1, characterized in that: The permanent magnet (1) comprises a first magnetizing portion (13) and a second magnetizing portion (14); the second magnetizing portion (14) comprises the embedded portion (12) and part of the covering portion (11); part of the covering portion (11) is located at two axial ends of the embedded portion (12) and extends axially from one end to the other end of the covering portion (11); part of the covering portion (11) is an extension of the embedded portion (12) in the covering portion (11); and parts of the second magnetizing portion (14) on both circumferential sides of the covering portion (11) form the first magnetizing portion (13).

5. The rotor structure according to claim 4, characterized in that: The first magnetizing part (13) and the second magnetizing part (14) have different magnetizing methods.

6. The rotor structure according to claim 5, characterized in that: The first magnetizing part (13) is magnetized along the axial direction of the rotor, and the second magnetizing part (14) is magnetized along the radial direction of the rotor.

7. The rotor structure according to claim 6, characterized in that: The polarity of the first magnetizing portion (13) on the side close to the rotor core (2) is the first polarity, and the polarity of the two second magnetizing portions (14) on both sides adjacent to the first magnetizing portion (13) on the side close to the rotor core (2) is the first polarity.

8. The rotor structure according to claim 1 or 2, characterized in that: The outer peripheral wall of the rotor core (2) comprises a plurality of arc surfaces arranged at intervals, and along the circumferential direction, the distance between the arc surfaces and the central axis of the rotor core (2) decreases from the middle to both ends.

9. The rotor structure according to claim 1, characterized in that: Along the axial direction of the rotor, there is no gap between the covering portion (11) and the rotor core (2).

10. The rotor structure according to claim 1 or 2, characterized in that: The width of the open slot of the fully open slot structure on the outer peripheral side of the rotor core (2) is x, and the height of the covering portion (11) along the rotor axial direction is y, then 0.5≤y / x≤1.

9.

11. The rotor structure according to claim 1, characterized in that: The permanent magnet (1) is formed by injection molding and is integrally embedded in and coated on the rotor core (2).

12. A motor, comprising a stator structure and a rotor structure, characterized in that: The rotor structure is the rotor structure according to any one of claims 1 to 11.

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