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 of an integral structure and comprises an axial portion (211) arranged at the axial end of the rotor core (11), a groove (213) is formed in the axial portion (211), and the part, extending out of the rotor core (11) in the axial direction, of the first permanent magnet (12) is inserted into the groove (213). According to the rotor structure, the magnetic gathering effect of the motor can be improved, the axial end magnetic leakage of the first permanent magnet is reduced, the number of parts is small, the number of assembling steps is small, assembling is easy, and the production cost is low.

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.

[0005] The comparative document 201880064666.X discloses a permanent magnet rotor assembly, in which two permanent magnet sets (one set is magnetized along the circumferential direction of the rotor, and the second set provides magnetic flux along the axial direction of the rotor) generate magnetic flux gathered by pole pieces, and there are end plates made of magnetic material, circumferentially magnetized magnets are placed in the circumferential gap between the pole pieces, and magnets providing axial magnetic flux are placed in the gap between the pole piece array and the end plates. The magnetic end plates in the comparative document are used to provide a return path for the magnetic flux from the magnets providing axial magnetic flux. However, in the field of household appliances, the rotor structure including multiple pole pieces, multiple scattered magnets and magnetic end plates has many parts, the magnetic end plates are difficult to fix, and the rotor assembly is difficult to assemble, resulting in high production and assembly costs, making it difficult to implement applications. Summary of the invention

[0006] The main purpose of the present invention is to provide a rotor structure and a motor, which can improve the magnetic field concentration effect of the motor and reduce the axial end magnetic leakage of the first permanent magnet, and has fewer parts, fewer assembly steps, simple assembly and low production cost.

[0007] 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 an integral structure, the second permanent magnet including an axial portion arranged at the axial end of the rotor core, the axial portion being provided with a groove, and the portion of the first permanent magnet extending axially out of the rotor core being inserted into the groove.

[0008] Furthermore, the second permanent magnet is an injection-molded magnetic steel.

[0009] Furthermore, the second permanent magnet also includes a connecting portion, which is filled in a through hole provided in the rotor core or the mounting groove, and the axial portions of the second permanent magnet are connected to form a whole through the connecting portion.

[0010] Further, the grooves arranged on the axial portion of the second permanent magnet do not penetrate the axial portion, and the number of the grooves is the same as the number of the rotor poles.

[0011] Furthermore, the second permanent magnet includes an axial portion and a connecting portion. The second permanent magnet cooperates with the first permanent magnet through a groove arranged on the axial portion. The first permanent magnet and the second permanent magnet are both magnetic flux sources. Except for the rotor core, no other magnetic conductive components are arranged in the rotor structure.

[0012] Furthermore, a protrusion is formed between adjacent grooves, and a polarity region of the protrusion corresponds to the position of a polarity region of the rotor core.

[0013] Further, on a plane perpendicular to the axial direction of the rotor core, a polarity region of the projection is adapted to a region shape of a corresponding polarity region of the rotor core, and a polarity region of the projection fills up the corresponding polarity region of the rotor core.

[0014] Furthermore, at least one end of the axial end portion of the rotor core is provided with an axial portion, and in the axial direction of the rotor core, the rotor core and the axial portion are fitted together.

[0015] Furthermore, the second permanent magnet is magnetized alternately along the axial direction of the rotor core with NS poles.

[0016] 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.

[0017] Further, the axial height of the rotor core is x, the axial height of the first permanent magnet is y, y>x, the axial height of the axial portion is z1, and the axial height of the protrusion is z2, wherein 0.2*(yx)≤z1≤1.6*(yx).

[0018] Furthermore, 2*z2≥(yx).

[0019] Further, z2=0.5*(yx).

[0020] Furthermore, 0.03≤(z1-z2) / z1≤0.7.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] Further, Do2=Do1.

[0025] Furthermore, the second permanent magnet is injection-molded ferrite or injection-molded neodymium iron boron.

[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 second permanent magnet is injection-molded or filled on the rotor core, or the second permanent magnet, the rotor core and the first permanent magnet are separately manufactured and then assembled together.

[0029] Furthermore, the rotor structure is filled with molding compound at the end and the inner gap and is molded into a whole.

[0030] 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.

[0031] According to the technical solution of the present invention, 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 an integral structure, and the second permanent magnet includes an axial portion arranged at the axial end of the rotor core, and a groove is arranged on the axial portion. The portion of the first permanent magnet extending axially out of the rotor core is inserted into the groove.

[0032] A first permanent magnet and a second permanent magnet are simultaneously arranged in the rotor, and the first permanent magnet and the second permanent magnet jointly provide magnetic flux for the motor, which can increase the output of the motor; the relative positions of the first permanent magnet and the second permanent magnet are designed, and the first permanent magnet is arranged to be inserted into the groove of the second permanent magnet, and the first permanent magnet serves as a part of the magnetic circuit for the magnetic flux of the second permanent magnet to flow, forming a first magnetic circuit, and drawing the magnetic flux of the protrusion of the second permanent magnet and the magnetic flux of part of the axial part into the rotor core; in addition to the first magnetic circuit, the magnetic flux of two adjacent poles of the axial part of the second permanent magnet forms a closed loop through the air at the end of the rotor assembly, forming a second magnetic circuit, and the first magnetic circuit and the first magnetic circuit After the magnetic lines of force of the two magnetic circuits are concentrated on the rotor core, they enter the air gap and the stator, which can greatly improve the magnetic concentration effect of the rotor. In addition, except for the rotor core, no other magnetic conductive components are set in the rotor structure, with fewer parts, fewer assembly steps, simple assembly, and low production cost. At the same time, the axial end leakage magnetic lines of force of the first permanent magnet need to pass through the second permanent magnet to form a closed loop. The second permanent magnet, which is a non-magnetic conductive component, weakens the end leakage of the first permanent magnet, and the flow direction of the magnetic lines of force of the second magnetic circuit is opposite to the flow direction of the leakage magnetic lines of force of the end of the first permanent magnet, and there is a mutual repulsion effect, which will further reduce the axial end leakage of the first permanent magnet and improve the magnetic field strength of the rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] 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:

[0034] Figure 1 A three-dimensional structural diagram showing a rotor structure of an embodiment of the present invention;

[0035] Figure 2 An exploded structural diagram showing a rotor structure of an embodiment of the present invention;

[0036] Figure 3 A partially exploded structural diagram showing a rotor structure of an embodiment of the present invention;

[0037] Figure 4 A three-dimensional structural diagram of a second permanent magnet of a rotor structure according to an embodiment of the present invention is shown;

[0038] Figure 5 A half-sectional structural diagram showing a three-dimensional structure of a second permanent magnet of a rotor structure according to an embodiment of the present invention;

[0039] Figure 6 A schematic side view of the structure of the second permanent magnet of the rotor structure of an embodiment of the present invention is shown;

[0040] Figure 7 A side structural diagram showing a rotor structure of an embodiment of the present invention;

[0041] Figure 8 A schematic diagram of a rotor structure viewed from above according to an embodiment of the present invention is shown;

[0042] Fig. 9 A schematic diagram of a rotor structure viewed from above according to an embodiment of the present invention is shown;

[0043] Fig.10 A three-dimensional structural diagram showing a rotor structure of another embodiment of the present invention;

[0044] Fig.11 A partially exploded structural diagram showing a rotor structure according to another embodiment of the present invention;

[0045] Fig.12 A half-sectional structural diagram showing a three-dimensional structure of a second permanent magnet of a rotor structure according to another embodiment of the present invention;

[0046] Fig.13 A schematic diagram of a rotor structure viewed from above according to another embodiment of the present invention is shown;

[0047] Fig.14 Shows Fig.13 AA section view;

[0048] Fig.15 Shows Fig.13 BB section view;

[0049] Fig.16 A schematic diagram showing the top structure of a second permanent magnet of a rotor structure according to another embodiment of the present invention is shown;

[0050] Fig.17 Shows Fig.16 BB section view;

[0051] Fig.18 Shows Fig.16 AA section view;

[0052] Fig.19 A schematic diagram showing the polarity direction of the rotor structure of the present invention is shown;

[0053] Fig. 20 A magnetic circuit schematic diagram of the rotor structure of the present invention is shown;

[0054] Fig.21 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;

[0055] Fig. 22 A comparison diagram of magnetic leakage coefficients of a motor according to an embodiment of the present invention and a motor according to a related art is shown;

[0056] Fig.23 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;

[0057] Fig.24 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

[0058] Fig.25 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.

[0059] The above drawings include the following reference numerals:

[0060] 11. rotor core; 111. limiting protrusion; 12. first permanent magnet; 21. second permanent magnet; 211. axial portion; 212. connecting portion; 213. groove; 214. protrusion. DETAILED DESCRIPTION

[0061] 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.

[0062] See also Figures 1 to 19 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, and the first permanent magnet 12 is mounted in the mounting groove. 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 an integral structure, and the second permanent magnet 21 includes an axial portion 211 arranged at the axial end of the rotor core 11, and a groove 213 is arranged on the axial portion 211, and the part of the first permanent magnet 12 extending axially out of the rotor core 11 is inserted into the groove 213.

[0063] like Fig. 20As shown, a first permanent magnet 12 and a second permanent magnet 21 are simultaneously arranged in the rotor, and the first permanent magnet 12 and the second permanent magnet 21 jointly provide magnetic flux for the motor, which can increase the output of the motor; the relative positions of the first permanent magnet 12 and the second permanent magnet 21 are designed, and the first permanent magnet 12 is arranged to be inserted into the groove 213 of the second permanent magnet 21, and the first permanent magnet 12 serves as a part of the magnetic circuit for the magnetic flux of the second permanent magnet 21 to flow, forming a first magnetic circuit, and pulling the magnetic flux of the protrusion 214 of the second permanent magnet 21 and the magnetic flux of part of the axial portion 211 into the rotor core 11; in addition to the first magnetic circuit, the magnetic flux of the two adjacent poles of the axial portion 211 of the second permanent magnet 21 passes through the rotor assembly. The air at the end forms a closed loop to constitute the second magnetic circuit. The magnetic lines of force of the first magnetic circuit and the second magnetic circuit are concentrated on the rotor core 11 and then enter the air gap and the stator, which can greatly improve the magnetic concentration effect of the rotor. In addition, except for the rotor core 11, no other magnetic conductive components are arranged in the rotor structure. The axial end leakage magnetic lines of force of the first permanent magnet 12 need to pass through the second permanent magnet 21 to form a closed loop. The second permanent magnet 21, which is a non-magnetic conductive component, weakens the end leakage of the first permanent magnet 12. The flow direction of the magnetic lines of force of the second magnetic circuit is opposite to the flow direction of the leakage magnetic lines of force of the end of the first permanent magnet 12, and there is a mutual repulsion effect. This will further reduce the axial end leakage of the first permanent magnet 12 and improve the magnetic field strength of the rotor.

[0064] The coordinated design of the first permanent magnet 12 and the second permanent magnet 21 in the rotor structure provides a return magnetic circuit for the magnetic flux of the second permanent magnet 21 through the first permanent magnet 12, and there is no need to add an additional magnetic end plate that cooperates with the magnetic circuit of the second permanent magnet 21. The magnetic dependence of the second permanent magnet 21 on the magnetic end plate can be eliminated. At the same time, the second permanent magnet 21 is an integral structure, with fewer rotor parts, fewer assembly steps, simple assembly, and low production cost.

[0065] 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.

[0066] 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 and the rotor structure.

[0067] 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.

[0068] In one embodiment, at least one end of the axial end of the rotor core 11 is provided with an axial portion 211, so that the magnetic circuit at the end of the motor can be arranged, so that the torque density is greater, the motor efficiency is higher, and the high performance of the motor is ensured. In the axial direction of the rotor core 11, the rotor core 11 and the axial portion 211 are fitted together to reduce the loss of the magnetic flux of the second permanent magnet 21 during circulation.

[0069] In one embodiment, the second permanent magnet 21 further includes a connecting portion 212, which is filled in a through hole provided in the rotor core 11 or the mounting slot, and the axial portion 211 of the second permanent magnet 21 is connected to form a whole through the connecting portion 212. Figure 4 As shown, in one embodiment of the present invention, the second permanent magnet 21 includes an axial portion 211 and a connecting portion 212, wherein the connecting portion 212 is filled in a through hole arranged on the side of the mounting groove close to the central axis of the rotor, and the connecting portion 212 connects the two axial portions 211 arranged at the axial ends of the rotor core 11 to form a whole. Fig.12 Another embodiment of the present invention is shown, in which the connecting portion 212 includes a portion filled in a through hole provided on one side of the mounting groove close to the central axis of the rotor, and a portion filled in a through hole provided on the rotor core 11 close to the outer circumference of the rotor, and the axial portion 211 and the connecting portion 212 form a cage structure. By filling the connecting portion 212, the second permanent magnet 21 is an integral structure, which can reduce the difficulty of assembling the rotor, reduce the assembly steps of the rotor, simplify the process, and save costs.

[0070] The second permanent magnet 21 includes an axial portion 211 and a connecting portion 212. The second permanent magnet 21 cooperates with the first permanent magnet 12 through a groove 213 arranged on the axial portion 211. The first permanent magnet 12 and the second permanent magnet 21 are both magnetic flux sources. Except for the rotor core 11, no other magnetic conductive components are arranged in the rotor structure.

[0071] In one embodiment, the grooves 213 provided on the axial portion 211 of the second permanent magnet 21 do not penetrate the axial portion 211, the number of the grooves 213 is the same as the number of the rotor poles, and a bump 214 is formed between adjacent grooves 213. The grooves 213 do not penetrate the axial portion 211, so that the axial portion 211 is a whole. Figure 5 As shown, in one embodiment of the present invention, a protrusion 214 is formed between two adjacent grooves 213, and the outer sides of the two adjacent protrusions 214 are disconnected, which can reduce the leakage magnetic flux at the outer circle of the rotor; in order to ensure the strength of the rotor, a magnetic bridge is provided on the inner side of the rotor core 11, and the second permanent magnet 21 connected to the inner side of the protrusion 214 helps to saturate the magnetic bridge and reduce the leakage magnetic flux of the first permanent magnet 12 at the inner magnetic bridge.

[0072] In one embodiment, a polarity region of the protrusion 214 corresponds to a position of a polarity region of the rotor core 11. That is, a polarity region of the protrusion 214 of the second permanent magnet 21 generates magnetic flux, and a polarity region of the rotor core 11 at a corresponding position is a 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.

[0073] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, a polar region of the protrusion 214 matches the region shape of a corresponding polar region of the rotor core 11, and the polar region of the protrusion 214 fills the corresponding polar region of the rotor core 11. "Filling" here means that there is no gap between the protrusion 214 and the rotor core 11 on a plane perpendicular to the axial direction of the rotor core 11.

[0074] 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.

[0075] 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, that is, the polarity of the second permanent magnet 21 on the side close to the rotor core 11 is the same as the polarity of the first permanent magnets 12 on both sides adjacent to the second permanent magnet 21 on the side close to the rotor core 11. Fig.19 In the illustrated embodiment, the second permanent magnet 21 is magnetized axially, and the first permanent magnet 12 is magnetized tangentially. Under a certain pole, the magnetization directions of both are directed toward the rotor core 11. Under this magnetization mode, the superposition of the magnetic flux of the first permanent magnet 12 and the second permanent magnet 21 can be achieved, thereby improving the no-load magnetic flux.

[0076] 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, the axial height of the axial portion 211 is z1, and the axial height of the protrusion 214 is z2, wherein 0.2*(yx)≤z1≤1.6*(yx).

[0077] In one embodiment, 2*z2≥(yx), interference between the axial portions 211 of the first permanent magnet 12 and the second permanent magnet 21 can be avoided to enable assembly of the first permanent magnet 12 and the second permanent magnet 21 .

[0078] In one embodiment, z2=0.5*(yx), which can form an optimal fit, effectively avoid the gap between the first permanent magnet 12 and the second permanent magnet 21, and reduce magnetic loss.

[0079] In one embodiment, 0.03≤(z1−z2) / z1≤0.7, so that the portion of the groove 213 that does not penetrate the axial portion 211 has a certain axial thickness ratio in the axial portion 211 to ensure the structural strength of the second permanent magnet 21 .

[0080] 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.

[0081] In one embodiment, Fig.10 As shown, Di2=Di1, that is, the inner diameter of the second permanent magnet 21 is the same as the inner diameter of the rotor core 11, so that the magnetic supply surface of the second permanent magnet 21 can be increased and the magnetic flux contribution of the second permanent magnet 21 can be improved.

[0082] 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 .

[0083] 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 slot structure while radially limiting the first permanent magnet 12, thereby reducing the radial magnetic leakage of the first permanent magnet 12.

[0084] 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.

[0085] 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.

[0086] 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 .

[0087] In one embodiment, Do2=Do1.

[0088] 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 limiting protrusion 111. The magnetic circuit area of ​​the limiting protrusion 111 is small and easy to saturate, and the position of the limiting protrusion 111 is close to the air gap, which is the magnetic flux gathering position. The iron loss here is large, and Do2≤Do1 can make the magnetic flux of the second permanent magnet 21 avoid the position of the limiting protrusion 111, reducing the iron loss of the motor. In motors with a small proportion of iron loss, Do2=Do1 is a better choice.

[0089] 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.

[0090] In one embodiment, 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 and in a radial direction, the rotor core 11 is magnetized alternately with N and S poles.

[0091] 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.

[0092] In one embodiment, the rotor core 11 is formed by laminating silicon steel sheets and has better magnetic conductivity.

[0093] In one embodiment, the rotor core 11 is an injection-molded magnetic steel, which has a pulling effect on the magnetic flux 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.

[0094] In one embodiment, the second permanent magnet 21 is injection-molded or filled on the rotor core 11 .

[0095] In one embodiment, the second permanent magnet 21 , the rotor core 11 , and the first permanent magnet 12 are manufactured separately and then assembled together.

[0096] The second permanent magnet 21 and the first permanent magnet 12 can be processed and manufactured in different ways, so the manufacturing method of the rotor can be selected according to production conditions, thereby improving the flexibility of rotor structure production.

[0097] 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.

[0098] See also Fig.21As 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.

[0099] See also Fig. 22 As shown, compared with the motor in the related art, the magnetic leakage coefficient of the motor using the rotor structure of the embodiment of the present invention is reduced by more than 10%, which effectively reduces the magnetic leakage and improves the motor performance.

[0100] See also Fig.23 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.

[0101] See also Fig.24 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.

[0102] See also Fig.25 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.

[0103] 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.

[0104] 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 "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0105] 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.

[0106] 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 an integral structure, the second permanent magnet (21) comprises an axial portion (211) arranged at the axial end of the rotor core (11), the axial portion (211) is provided with a groove (213), and the portion of the first permanent magnet (12) extending axially out of the rotor core (11) is inserted into the groove (213).

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

3. The rotor structure according to claim 1, characterized in that: The second permanent magnet (21) further comprises a connecting portion (212), wherein the connecting portion (212) is filled in a through hole provided in the rotor core (11) or the mounting groove, and the axial portion (211) of the second permanent magnet (21) is connected to form a whole through the connecting portion (212).

4. The rotor structure according to claim 1, characterized in that: The grooves (213) arranged on the axial portion (211) of the second permanent magnet (21) do not penetrate the axial portion (211), and the number of the grooves (213) is the same as the number of rotor poles.

5. The rotor structure according to claim 1, characterized in that: The second permanent magnet (21) comprises an axial portion (211) and a connecting portion (212); the second permanent magnet (21) cooperates with the first permanent magnet (12) via a groove (213) arranged on the axial portion (211); 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 arranged in the rotor structure.

6. The rotor structure according to claim 1, characterized in that: A bulge (214) is formed between adjacent grooves (213), and a polarity region of the bulge (214) corresponds to the position of a polarity region of the rotor core (11).

7. The rotor structure according to claim 6, characterized in that: On a plane perpendicular to the axial direction of the rotor core (11), a polar region of the protrusion (214) is adapted to the regional shape of a corresponding polar region of the rotor core (11), and a polar region of the protrusion (214) fills the corresponding polar region of the rotor core (11).

8. The rotor structure according to claim 1, characterized in that: At least one end of the axial end of the rotor core (11) is provided with the axial portion (211), and in the axial direction of the rotor core (11), the rotor core (11) and the axial portion (211) are fitted together.

9. 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.

10. The rotor structure according to claim 1 or 9, 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.

11. The rotor structure according to claim 6, 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, the axial height of the axial portion (211) is z1, and the axial height of the protrusion (214) is z2, wherein 0.2*(yx)≤z1≤1.6*(yx).

12. The rotor structure according to claim 11, characterized in that: 2*z2≥(yx).

13. The rotor structure according to claim 12, characterized in that: z2=0.5*(yx).

14. The rotor structure according to claim 11, characterized in that: 0.03≤(z1-z2) / z1≤0.

7.

15. The rotor structure according to any one of claims 1 to 9, 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.

16. The rotor structure according to claim 15, 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).

17. The rotor structure according to any one of claims 1 to 9, 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.

18. The rotor structure according to claim 17, characterized in that: Do2=Do1.

19. The rotor structure according to claim 2, characterized in that: The second permanent magnet (21) is injection-molded ferrite or injection-molded neodymium iron boron.

20. 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.

21. 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.

22. The rotor structure according to claim 1, characterized in that: The second permanent magnet (21) is injection-molded, coated or filled on the rotor core (11), or the second permanent magnet (21), the rotor core (11) and the first permanent magnet (12) are separately manufactured and then assembled together.

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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