Rotor structure and motor

Abstract

The invention provides a rotor structure and a motor. The rotor structure comprises a rotor iron core (11), a first permanent magnet (12) and a second permanent magnet (21), the rotor iron core (11) is provided with an installation groove, the first permanent magnet (12) is installed in the installation groove, and the axial height of the first permanent magnet (12) is larger than that of the rotor iron core (11) in the axial direction of the rotor iron core (11); the second permanent magnet (21) is arranged at the axial end part of the rotor iron core (11), the second permanent magnet (21) is of an integral structure, a through groove (22) is formed in the second permanent magnet (21), and at least one end of the first permanent magnet (12) extends out of the rotor iron core (11) along the axial direction and is inserted into the through groove (22); the second permanent magnet (21) further comprises annular parts (23) and magnetic pole parts (24), and the magnetic pole parts (24) are connected into a whole through the annular parts (23). According to the rotor structure, the magnetic gathering effect of the motor can be effectively improved, and the comprehensive utilization rate of the permanent magnets is improved.

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 improve the comprehensive utilization rate of the permanent magnets.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a rotor structure is provided, including a rotor core, a first permanent magnet and a second permanent magnet, the rotor core having a mounting groove, the first permanent magnet being mounted in the mounting groove, and the axial height of the first permanent magnet along the axial direction of the rotor core being greater than the axial height of the rotor core; the second permanent magnet being arranged at the axial end of the rotor core, the second permanent magnet being an integral structure, and having a through groove thereon, at least one end of the first permanent magnet extending axially out of the rotor core and inserted into the through groove, the second permanent magnet also comprising an annular portion and a magnetic pole portion, the magnetic pole portion being formed into a whole by connection of the annular portion.

[0007] Furthermore, the annular portion is located radially inward of the second permanent magnet, through grooves are formed between adjacent magnetic pole portions, the magnetic pole portions are radially arranged along the circumference of the annular portion, and are connected to the annular portion through connecting ribs to form a whole with the annular portion.

[0008] Furthermore, the rotor structure includes a through hole, which is arranged radially inward of the first permanent magnet and passes through the rotor core and the second permanent magnet.

[0009] Further, the first permanent magnet is magnetized tangentially, and the second permanent magnet is magnetized axially.

[0010] Furthermore, the second permanent magnet is an injection-molded magnetic steel.

[0011] Furthermore, at least one axial end of the rotor core is provided with a second permanent magnet.

[0012] Furthermore, a through hole is formed between the through slot and the first permanent magnet located in the through slot.

[0013] Furthermore, the first permanent magnet and the second permanent magnet are both magnetic flux sources, and except for the rotor core, no other magnetic conductive components are provided in the rotor structure.

[0014] Further, the axial height of the rotor core is x, the axial height of the first permanent magnet is y, y>x, and the axial height of the second permanent magnet is z, wherein 0.2*(yx)≤z≤1.2*(yx).

[0015] Further, z≤0.5*(yx).

[0016] Further, on a plane perpendicular to the axial direction of the rotor core, the inner diameter of the second permanent magnet is Di2, the inner diameter of the rotor core is Di1, and Di2≥Di1.

[0017] Furthermore, a limiting protrusion is provided on the outer circumferential side of the rotor core, and the limiting protrusion extends laterally from both circumferential sides of the rotor core to form a radial limit for the first permanent magnet.

[0018] 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.

[0019] Further, on a plane perpendicular to the axial direction of the rotor core, the maximum value of the outer diameter of the second permanent magnet is Do2, the maximum value of the outer diameter of the rotor core is Do1, and Do2≤Do1.

[0020] Further, Do2=Do1.

[0021] Further, a polarity region of the magnetic pole portion is arranged corresponding to a polarity region of the rotor core.

[0022] Further, a polarity region of the magnetic pole portion is adapted to a region shape of a corresponding polarity region of the rotor core, and a polarity region of the magnetic pole portion fills up a polarity region corresponding to the rotor core.

[0023] Furthermore, the second permanent magnet is injection-molded ferrite or injection-molded neodymium iron boron.

[0024] Furthermore, the second permanent magnet is magnetized alternately along the axial direction of the rotor core with NS poles.

[0025] Further, the polarity of the second permanent magnet on one side close to the rotor core is the first polarity, and the polarities of the two first permanent magnets on both sides adjacent to the second permanent magnet on one side close to the rotor core are the first polarity.

[0026] Furthermore, the first permanent magnet is a sintered permanent magnet or an injection molded permanent magnet.

[0027] Furthermore, the rotor core is formed by stacking silicon steel sheets, or the rotor core is injection-molded magnetic steel, and the rotor core NS poles are alternately magnetized along the radial direction on a plane perpendicular to the axial direction of the rotor core.

[0028] Furthermore, the rotor structure is filled with molding compound at the end and the inner gap and is molded into a whole.

[0029] 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.

[0030] The technical solution of the present invention is applied, and the rotor structure includes a rotor core, a first permanent magnet and a second permanent magnet. The rotor core has a mounting groove, and the first permanent magnet is mounted in the mounting groove. Along the axial direction of the rotor core, the axial height of the first permanent magnet is greater than the axial height of the rotor core; the second permanent magnet is arranged at the axial end of the rotor core, and the second permanent magnet is an integral structure, on which a through slot is arranged, and at least one end of the first permanent magnet extends out of the rotor core in the axial direction and is inserted into the through slot. The second permanent magnet also includes an annular portion and a magnetic pole portion, and the magnetic pole portion is connected by the annular portion to form a whole.

[0031] The rotor structure is provided with a first permanent magnet and a second permanent magnet at the same time. The first permanent magnet and the second permanent magnet jointly provide magnetic flux for the motor, thereby increasing the torque density of the motor. The design of the relative positions of the first permanent magnet and the second permanent magnet allows the first permanent magnet to serve as a part of the magnetic circuit through which the magnetic flux of the second permanent magnet flows. The magnetic flux of the first permanent magnet and the second permanent magnet gather on the rotor core and then enter the air gap and the stator, thereby improving the magnetic flux concentration effect of the motor, effectively improving the efficiency and torque density of the motor, and increasing the output of the motor. The first permanent magnet serves as both a magnetic flux source and can draw the magnetic flux of the second permanent magnet into the rotor core. At the same time, the second permanent magnet serves as both a magnetic flux source and can block the leakage magnetic flux of the first permanent magnet, thereby achieving a higher comprehensive utilization rate of the permanent magnets. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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:

[0033] Figure 1 A three-dimensional structural diagram showing a rotor structure of an embodiment of the present invention;

[0034] Figure 2 An exploded structural diagram showing a rotor structure of an embodiment of the present invention;

[0035] Figure 3 A side structural diagram showing a rotor structure of an embodiment of the present invention;

[0036] Figure 4 A schematic diagram showing the three-dimensional structure of a second permanent magnet according to an embodiment of the present invention is shown;

[0037] Figure 5 A schematic diagram of the structure of a second permanent magnet according to an embodiment of the present invention is shown;

[0038] Figure 6 Shows Figure 5 AA section view;

[0039] Figure 7 Shows Figure 5 BB section view;

[0040] Figure 8 A top view of a rotor assembly showing an embodiment of the present invention;

[0041] Fig. 9 A top view of a rotor assembly showing an embodiment of the present invention;

[0042] Fig.10 A top view showing a rotor structure of an embodiment of the present invention;

[0043] Fig.11 A magnetic circuit schematic diagram of a rotor structure according to an embodiment of the present invention is shown;

[0044] Fig.12 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;

[0045] Fig.13 A comparison diagram of the comprehensive utilization rate of permanent magnets of a motor according to an embodiment of the present invention and a motor according to related art is shown;

[0046] Fig.14 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;

[0047] Fig.15 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

[0048] Fig.16 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.

[0049] The above drawings include the following reference numerals:

[0050] 11. rotor core; 111. limiting protrusion; 12. first permanent magnet; 21. second permanent magnet; 22. through slot; 23. annular portion; 24. magnetic pole portion; 31. through hole. DETAILED DESCRIPTION

[0051] 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.

[0052] See also Figures 1 to 10 As shown, according to an embodiment of the present invention, the rotor structure includes a rotor core 11, a first permanent magnet 12 and a second permanent magnet 21. The rotor core 11 has a mounting groove, the first permanent magnet 12 is mounted in the mounting groove, and along the axial direction of the rotor core 11, the axial height of the first permanent magnet 12 is greater than the axial height of the rotor core 11; the second permanent magnet 21 is arranged at the axial end of the rotor core 11, the second permanent magnet 21 is an integral structure, and a through slot 22 is arranged on the second permanent magnet 21, at least one end of the first permanent magnet 12 extends out of the rotor core 11 in the axial direction and is inserted into the through slot 22. The second permanent magnet 21 also includes an annular portion 23 and a magnetic pole portion 24, and the magnetic pole portion 24 is connected to form a whole by the annular portion 23.

[0053] A first permanent magnet 12 and a second permanent magnet 21 are simultaneously arranged in the rotor structure, and the first permanent magnet 12 and the second permanent magnet 21 jointly provide magnetic flux for the motor, thereby increasing the torque density of the motor; the design of the relative positions of the first permanent magnet 12 and the second permanent magnet 21 can make the first permanent magnet 12 serve as a part of the magnetic circuit in which the magnetic flux of the second permanent magnet 21 flows, and the magnetic flux of the first permanent magnet 12 and the second permanent magnet 21 gather on the rotor core 11 and then enter the air gap and the stator, thereby improving the magnetic flux concentration effect of the motor, effectively improving the motor efficiency and torque density, and increasing the motor output; the first permanent magnet 12 serves as a magnetic flux source and can also draw the magnetic flux of the second permanent magnet 21 into the rotor core 11, and at the same time, the second permanent magnet 21 serves as a magnetic flux source and can block the leakage magnetic flux of the first permanent magnet 12, and the comprehensive utilization rate of the permanent magnets is higher.

[0054] In one embodiment, the first permanent magnet 12 is magnetized tangentially, and the second permanent magnet 21 is magnetized axially. In this embodiment, the first permanent magnet 12 with a larger axial height is set to be magnetized tangentially, and the second permanent magnet 21 set at the axial end of the rotor core 11 is magnetized axially, which can achieve the continuity of the magnetic flux of the first permanent magnet 12 and the second permanent magnet 21, so that the two can more effectively provide magnetic flux for the motor together, effectively increasing the motor output.

[0055] In one embodiment, the second permanent magnet 21 is an injection-molded magnetic steel. Using the injection-molded magnetic steel can reduce the rotor saturation and iron loss on the one hand, and on the other hand, the injection-molded magnetic steel has a higher degree of freedom in shape, which can reduce the difficulty of manufacturing the second permanent magnet 21 .

[0056] In one embodiment, the second permanent magnet 21 is injection-molded ferrite or injection-molded neodymium iron boron. The second permanent magnet 21 may also be injection-molded magnetic steel of other material types.

[0057] In one embodiment, at least one axial end of the rotor core 11 is provided with a second permanent magnet 21, so that the magnetic circuit at the motor end can be arranged, so that the torque density is higher, the motor efficiency is higher, and the high performance of the motor is ensured.

[0058] In one embodiment, second permanent magnets 21 are respectively disposed at two axial ends of the rotor core 11 .

[0059] In one embodiment, the annular portion 23 is located radially inside the second permanent magnet 21, and a through slot 22 is formed between each adjacent magnetic pole portion 24. The magnetic pole portion 24 is radially arranged along the circumference of the annular portion 23, and is connected to the annular portion 23 through a connecting rib, forming a whole with the annular portion 23. In order to ensure the strength of the rotor, a magnetic bridge is provided on the inner side of the rotor core 11. The annular portion 23 provided radially inside the second permanent magnet 21 helps to saturate the magnetic bridge and reduce the leakage of the first permanent magnet 12 at the inner magnetic bridge. In this embodiment, the second permanent magnet 21 is connected to form an integral structure through the annular portion 23. That is, the second permanent magnet 21 is a whole, rather than divided into blocks.

[0060] In one embodiment, a through hole 31 is provided on the rotor structure, and the through hole 31 is provided on the radial inner side of the first permanent magnet 12, and passes through the rotor core 11 and the second permanent magnet 21. A through hole 31 is formed between the through slot 22 and the first permanent magnet 12 located in the through slot 22. The through hole 31 passes through the rotor core 11 and the second permanent magnet 21, and can be used as a positioning hole in the rotor manufacturing process; if the rotor is a plastic-coated structure as a whole, the through hole 31 can also be used as a circulation hole for the plastic packaging material.

[0061] In one embodiment, a support protrusion protruding radially outward is provided on the radially inner side wall of the mounting groove of the rotor core 11, and the top shape of the support protrusion matches the radially inner side wall of the first permanent magnet 12 to form surface contact.

[0062] In this embodiment, through holes 31 are formed between the two sides of the support protrusion and the side walls of the installation groove. The top shape of the support protrusion is adapted to the surface of the first permanent magnet 12 facing the support protrusion, so that the two can form a surface contact, so that the first permanent magnet 12 is installed and positioned by using the support protrusion. In this embodiment, no support protrusion is provided in the through groove 22, and a U-shaped structure is formed on the radial inner side of the through groove 22. The first permanent magnet 12 is limited by the U-shaped structure, and the U-shaped structure forms a through hole 31.

[0063] In one embodiment, the first permanent magnet 12 and the second permanent magnet 21 are both magnetic flux sources, and except for the rotor core 11 , no other magnetic conductive components are provided in the rotor structure.

[0064] In one embodiment, the axial height of the rotor core 11 is x, the axial height of the first permanent magnet 12 is y, y>x, and the axial height of the second permanent magnet 21 is z, wherein 0.2*(yx)≤z≤1.2*(yx). By limiting the relationship between the axial heights of the rotor core 11, the first permanent magnet 12, and the second permanent magnet 21, on the one hand, a high utilization rate of the rotor core 11 and the permanent magnet material can be ensured, and on the other hand, under the size matching within this range, the rotor end leakage flux can be minimized.

[0065] Furthermore, z≤0.5*(yx) is a more optimal size match. At this time, the magnetic field lines of the second permanent magnet 21 can completely enter the rotor core 11 through the traction of the first permanent magnet 12. At the same time, the second permanent magnet 21 also blocks the self-leakage magnetic path of the first permanent magnet 12, thereby improving the comprehensive utilization rate of the permanent magnet. Optimally, z=0.5*(yx).

[0066] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the inner diameter of the second permanent magnet 21 is Di2, the inner diameter of the rotor core 11 is Di1, and Di2≥Di1. The inner hole of the rotor core 11 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 second permanent magnet 21 can be filled with plastic packaging material or other materials to enhance the strength of the rotor.

[0067] In one embodiment, a limiting protrusion 111 is disposed on the outer circumference of the rotor core 11 . The limiting protrusion 111 extends laterally from both circumferential sides of the rotor core 11 and forms a radial limit for the first permanent magnet 12 .

[0068] In this embodiment, the limiting protrusion 111 is located at the outermost periphery of the rotor core 11 and extends circumferentially from the two side surfaces of the rotor core 11 in the circumferential direction, and the two limiting protrusions 111 extending in opposite directions are arranged at intervals, thereby forming an open groove structure while radially limiting the first permanent magnet 12, thereby reducing the leakage magnetic field of the first permanent magnet 12 at the outer periphery of the rotor core 11.

[0069] In one embodiment, the outer peripheral wall of the rotor core 11 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 11 decreases from the middle to both ends.

[0070] In this embodiment, since the rotor core 11 forms an open slot structure, the outer peripheral structure of the rotor core 11 is not a full circle, but a plurality of arc segments arranged at intervals. The middle of each arc segment protrudes radially outward to form an arc structure that is misaligned with the center of the rotor outer circle. This can improve the air gap magnetic density between the stator and the rotor, is more conducive to forming a sine curve, and improves the working performance of the motor.

[0071] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11 , the maximum value of the outer diameter of the second permanent magnet 21 is Do2 , the maximum value of the outer diameter of the rotor core 11 is Do1 , and Do2 ≤ Do1 .

[0072] In one embodiment, Do2=Do1.

[0073] For the motor, on the one hand, the stator structure is sleeved on the outside of the rotor structure, and an air gap is set between the rotor structure and the stator structure. This setting can make way for the assembly of the stator structure; on the other hand, in order to ensure that the first permanent magnet 12 will not fall off after being assembled into the rotor core 11, the outer circle of the rotor core 11 may be provided with a card point. The card point magnetic circuit area is small and easy to saturate, and the card point is located close to the air gap, which is the magnetic flux gathering position. The iron loss here is large. Do2≤Do1 can make the magnetic flux of the second permanent magnet 21 avoid the card point position and reduce the iron loss of the motor. In motors with a small iron loss ratio, Do2=Do1 is a better choice.

[0074] In one embodiment, one polarity region of the magnetic pole portion 24 is arranged to correspond to one polarity region of the rotor core 11 .

[0075] In one embodiment, a polar region of the magnetic pole portion 24 is adapted to a region shape of a corresponding polar region of the rotor core 11, and a polar region of the magnetic pole portion 24 fills up the corresponding polar region of the rotor core 11. “Filled up” here means that there is no gap between the rotor core 11 and the second permanent magnet 21 on a plane perpendicular to the axial direction of the rotor core 11.

[0076] In this embodiment, a polarity region of the magnetic pole portion 24 generates magnetic flux, and a polarity region of the rotor core 11 at a corresponding position is the magnetic path of the magnetic flux. The corresponding arrangement of the two can shorten the magnetic path as much as possible and reduce magnetic loss.

[0077] In one embodiment, the second permanent magnets 21 are magnetized alternately along the axial direction of the rotor core 11 with N and S poles.

[0078] In one embodiment, the polarity of the second permanent magnet 21 close to the rotor core 11 is the first polarity, and the polarities of the two first permanent magnets 12 on both sides adjacent to the second permanent magnet 21 close to the rotor core 11 are the first polarity.

[0079] like Fig.11 In the illustrated embodiment, the second permanent magnet 21 is magnetized axially, and the first permanent magnet 12 is magnetized tangentially. The magnetic lines of force of the second permanent magnet 21 enter the rotor core 11 with the portion of the first permanent magnet 12 extending out of the rotor core 11 as the magnetic path, and the magnetic lines of force generated by the portion of the first permanent magnet 12 inserted into the rotor core 11, after being concentrated, enter the air gap and the stator through the rotor core 11, which can greatly enhance the magnetic concentration effect of the motor, and improve the torque density and efficiency of the motor.

[0080] In one embodiment, the first permanent magnet 12 is a sintered permanent magnet or an injection-molded permanent magnet, which can be determined according to the use occasion and use temperature of the motor.

[0081] In one embodiment, the rotor core 11 is formed by laminating silicon steel sheets, or the rotor core 11 is injection-molded magnetic steel. In a plane perpendicular to the axial direction of the rotor core 11 , along the radial direction, the rotor core 11 is alternately magnetized along the NS poles.

[0082] The rotor core 11 is a path carrier for the flux of the first permanent magnet 12 and the second permanent magnet 21 to flow, and has the function of clearing and guiding the flux.

[0083] In one embodiment, the rotor core 11 is formed by laminating silicon steel sheets and has better magnetic conductivity.

[0084] In one embodiment, the rotor core 11 is an injection-molded magnetic steel, which has a pulling effect on the magnetic lines of force of the first permanent magnet 12 and the second permanent magnet 21 after magnetization, and can also guide the magnetic flux to enter the air gap and the stator after magnetic concentration.

[0085] In one embodiment, the rotor structure is filled with molding compound at the end and the internal gap and molded into a whole, which can ensure the overall structural strength of the rotor assembly.

[0086] See also Fig.12 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.

[0087] See also Fig.13 As shown, compared with the motors in the related art, the motors using the rotor structure of the embodiments of the present invention have a higher comprehensive utilization rate of permanent magnets, especially under heavy loads, the utilization rate of permanent magnets is increased by more than 35%.

[0088] See also Fig.14 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.

[0089] See also Fig.15 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.

[0090] See also Fig.16 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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 rotor core (11), a first permanent magnet (12) and a second permanent magnet (21); the rotor core (11) has a mounting groove, the first permanent magnet (12) is mounted in the mounting groove, and along the axial direction of the rotor core (11), the axial height of the first permanent magnet (12) is greater than the axial height of the rotor core (11); the second permanent magnet (21) is arranged at the axial end of the rotor core (11), the second permanent magnet (21) is an integral structure, and a through groove (22) is arranged thereon, at least one end of the first permanent magnet (12) extends out of the rotor core (11) along the axial direction and is inserted into the through groove (22); the second permanent magnet (21) further comprises an annular portion (23) and a magnetic pole portion (24), and the magnetic pole portion (24) is connected to form a whole by the annular portion (23).

2. The rotor structure according to claim 1, characterized in that: The annular portion (23) is located radially inward of the second permanent magnet (21), and the through groove (22) is formed between each adjacent magnetic pole portion (24). The magnetic pole portion (24) is radially arranged along the circumference of the annular portion (23) and is connected to the annular portion (23) via connecting ribs, thereby forming a whole with the annular portion (23).

3. The rotor structure according to claim 1, characterized in that: The rotor structure comprises a through hole (31), wherein the through hole (31) is arranged on the radial inner side of the first permanent magnet (12) and passes through the rotor core (11) and the second permanent magnet (21).

4. The rotor structure according to claim 1, characterized in that: The first permanent magnet (12) is magnetized tangentially, and the second permanent magnet (21) is magnetized axially.

5. The rotor structure according to claim 1, characterized in that: The second permanent magnet (21) is an injection-molded magnetic steel.

6. The rotor structure according to claim 1, characterized in that: The second permanent magnet (21) is disposed at at least one end of the axial end portion of the rotor core (11).

7. The rotor structure according to claim 1, characterized in that: A through hole (31) is formed between the through slot (22) and the first permanent magnet (12) located in the through slot (22).

8. The rotor structure according to claim 1, characterized in that: The first permanent magnet (12) and the second permanent magnet (21) are both magnetic flux sources, and except for the rotor core (11), no other magnetic conductive components are provided in the rotor structure.

9. The rotor structure according to any one of claims 1 to 8, characterized in that: The axial height of the rotor core (11) is x, the axial height of the first permanent magnet (12) is y, y>x, and the axial height of the second permanent magnet (21) is z, wherein 0.2*(yx)≤z≤1.2*(yx).

10. The rotor structure according to claim 9, characterized in that: z≤0.5*(yx).

11. The rotor structure according to any one of claims 1 to 8, characterized in that: On a plane perpendicular to the axial direction of the rotor core (11), the inner diameter of the second permanent magnet (21) is Di2, the inner diameter of the rotor core (11) is Di1, and Di2≥Di1.

12. The rotor structure according to claim 11, characterized in that: A limiting protrusion (111) is provided on the outer circumferential side of the rotor core (11), and the limiting protrusion (111) extends laterally from both circumferential sides of the rotor core (11) and forms a radial limit for the first permanent magnet (12).

13. The rotor structure according to any one of claims 1 to 8, characterized in that: The outer peripheral wall of the rotor core (11) 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 (11) decreases from the middle to both ends.

14. The rotor structure according to any one of claims 1 to 8, characterized in that: On a plane perpendicular to the axial direction of the rotor core (11), the maximum value of the outer diameter of the second permanent magnet (21) is Do2, the maximum value of the outer diameter of the rotor core (11) is Do1, and Do2≤Do1.

15. The rotor structure according to claim 14, characterized in that: Do2=Do1.

16. The rotor structure according to any one of claims 1 to 8, characterized in that: A polarity region of the magnetic pole portion (24) is arranged corresponding to a polarity region of the rotor core (11).

17. The rotor structure according to claim 16, characterized in that: A polarity region of the magnetic pole portion (24) is adapted to the region shape of a corresponding polarity region of the rotor core (11), and a polarity region of the magnetic pole portion (24) fills the corresponding polarity region of the rotor core (11).

18. The rotor structure according to claim 5, characterized in that: The second permanent magnet (21) is injection-molded ferrite or injection-molded neodymium iron boron.

19. The rotor structure according to claim 1, characterized in that: The second permanent magnet (21) is magnetized alternately along the axial direction of the rotor core (11) with N and S poles.

20. The rotor structure according to claim 1 or 19, characterized in that: The polarity of the second permanent magnet (21) on the side close to the rotor core (11) is the first polarity, and the polarity of the two first permanent magnets (12) on both sides adjacent to the second permanent magnet (21) on the side close to the rotor core (11) is the first polarity.

21. The rotor structure according to claim 1, characterized in that: The first permanent magnet (12) is a sintered permanent magnet or an injection-molded permanent magnet.

22. The rotor structure according to claim 1, characterized in that: The rotor core (11) is formed by stacking silicon steel sheets, or the rotor core (11) is injection-molded magnetic steel. In a plane perpendicular to the axial direction of the rotor core (11), along the radial direction, the rotor core (11) is magnetized alternately with N and S poles.

23. The rotor structure according to claim 1, characterized in that The rotor structure is filled with molding compound at the end and the inner gap and is molded into a whole.

24. 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 23.

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