Rotor structure and motor

Abstract

The invention provides a rotor structure and a motor. The rotor structure comprises a rotor iron core, a first permanent magnet and a second permanent magnet, the rotor iron core is provided with an installation groove, the first permanent magnet is installed in the installation groove, and the axial height of the first permanent magnet is larger than that of the rotor iron core; the second permanent magnet is arranged at the axial end part of the rotor iron core, a groove is formed in the second permanent magnet, the part, extending out of the rotor iron core in the axial direction, of the first permanent magnet is inserted into the groove, the first permanent magnet is magnetized in the radial direction and / or tangential direction of the rotor iron core, and the second permanent magnet is magnetized in the axial direction; the rotor structure is plastically packaged into a plastic-coated rotor after the end part and / or the internal gap are / is filled with a plastic packaging material, and at least one non-filling part is arranged on the axial end surface of at least one end of the plastic-coated rotor. 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 assembling difficulty of the rotor is reduced, the number of parts is small, and the production cost is low.

Description

Technical Field

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

[0002] With the improvement of motor energy efficiency standards, higher requirements are placed on the energy efficiency level of motors. For permanent magnet motors, it is necessary to further improve the efficiency and torque density of the motors.

[0003] Currently, there are two main technical approaches to improve motor efficiency and torque density. One approach is to incorporate permanent magnets to achieve a larger air gap magnetic flux and a greater magnetic density. However, due to the fixed rotor magnetic circuit structure, the improvement in energy efficiency is limited. Another approach is to increase the motor's salient pole ratio and magnetic reluctance torque by utilizing the rotor structure 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 makes the motor's torque density inferior to that of a permanent magnet motor.

[0004] Therefore, for current motors, how to further improve motor efficiency and torque density is an urgent problem to be solved.

[0005] Prior art document 201880064666.X discloses a permanent magnet rotor assembly. This assembly contains two sets of permanent magnets (a first set magnetized circumferentially along the rotor, and a second set providing magnetic flux axially along the rotor) that generate magnetic flux concentrated through pole pieces. An end plate made of magnetic material is present. 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 plate. The magnetic end plate in the prior art document provides a return path for the magnetic flux from the magnets providing axial magnetic flux. However, in the home appliance industry, rotor structures involving multiple magnetic pole pieces, multiple dispersed magnets, and magnetic end plates have numerous components, are difficult to fix in place, and have high assembly complexity, resulting in high production and assembly costs and hindering practical application. Summary of the Invention

[0006] The main objective of this invention is to provide a rotor structure and motor that can improve the magnetizing effect of the motor, reduce the leakage flux at the axial end of the first permanent magnet, reduce the assembly difficulty of the rotor, and have fewer parts and lower production costs.

[0007] To achieve the above objectives, according to one aspect of the present invention, a rotor structure is provided, comprising 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 disposed at the axial end of the rotor core, and a groove is provided on the second permanent magnet. A protrusion is formed between adjacent grooves. The portion of the first permanent magnet extending axially out of the rotor core is inserted into the groove. The first permanent magnet is magnetized along the radial direction and / or tangential direction of the rotor core, and the second permanent magnet is magnetized along the axial direction of the rotor core. The rotor structure is plastic-encapsulated into a plastic-coated rotor after the end and / or internal gaps are filled with encapsulating material. At least one non-filled portion is provided on the axial end face of at least one end of the plastic-coated rotor, and the non-filled portion is not filled with encapsulating material.

[0008] Furthermore, along the axial direction of the plastic-coated rotor, the unfilled portion extends from the axial end face of the plastic-coated rotor to the axial end face of the second permanent magnet on the side away from the rotor core.

[0009] Furthermore, multiple non-filled portions are evenly distributed on one axial end face of the plastic-coated rotor.

[0010] Furthermore, a projection is made on one end face of the plastic-coated rotor along the axial direction of the rotor, and in this projection plane, the unfilled portion coincides with the protrusion portion of the second permanent magnet.

[0011] Furthermore, the second permanent magnet is provided with a hole structure, and the rotor core is provided with a through hole. At least one hole structure and at least one through hole are provided correspondingly and pass through the rotor core in the axial direction.

[0012] Furthermore, a projection is made on one end face of the plastic-coated rotor along the axial direction of the rotor, and in this projection plane, the unfilled portion is located radially outside the hole structure.

[0013] Furthermore, the area of ​​the overlapping portion of a non-filled part and a hole structure at the corresponding position is not greater than half the area of ​​the hole structure at that position.

[0014] Furthermore, along the axial direction of the plastic-coated rotor, the axial thickness of the encapsulant on the side of the plastic-coated rotor where the non-filled portion is provided is not greater than the axial thickness of the encapsulant on the side of the plastic-coated rotor where the non-filled portion is not provided.

[0015] Furthermore, a projection is made on one end face of the rotor core along the axial direction of the rotor core, and within this projection plane, the radial width of the groove is smaller than the radial width of the protrusion.

[0016] Furthermore, the second permanent magnet has an outer peripheral surface near the air gap side and an inner peripheral surface near the shaft side, and at least one window is provided on the outer peripheral surface and / or the inner peripheral surface of the second permanent magnet.

[0017] Furthermore, the window is located on the outer peripheral surface of the second permanent magnet.

[0018] Furthermore, a limiting protrusion is provided on the outer periphery of the rotor core. The limiting protrusion extends laterally from both sides of the rotor core in the circumferential direction and forms a radial limit on the first permanent magnet. An opening groove is formed between the limiting protrusion and the first permanent magnet. The opening groove and window correspondingly provided in the circumferential direction are connected in the axial direction of the rotor core.

[0019] Furthermore, the second permanent magnet is an injection-molded magnet.

[0020] Furthermore, after the first and second permanent magnets are magnetized, they are divided into multiple polarity regions. The polarity of the side of the second permanent magnet closest to the rotor core is the first polarity, and the polarity of the two first permanent magnets on the two sides adjacent to the second permanent magnet, which are also close to the rotor core, is the first polarity.

[0021] Furthermore, 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 second permanent magnet is z1, and the axial height of the bump is z2, where 0.2*(yx)≤z1≤1.6*(yx).

[0022] Furthermore, 0.03≤(z1-z2) / z1≤0.7.

[0023] According to another aspect of the present invention, an electric motor is provided, comprising a stator structure and a rotor structure, wherein the rotor structure is the rotor structure described above, and the stator structure is sleeved on the outer periphery of the rotor structure.

[0024] Furthermore, the axial height of the rotor core is x; the stator structure includes a stator core, the axial height of which is w, and x ≥ 1.05 * w.

[0025] 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 installed 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 disposed at the axial end of the rotor core, and a groove is provided on the second permanent magnet. A protrusion is formed between adjacent grooves. The portion of the first permanent magnet extending axially out of the rotor core is inserted into the groove. The first permanent magnet is magnetized along the radial direction and / or tangential direction of the rotor core, and the second permanent magnet is magnetized along the axial direction of the rotor core. The rotor structure is plastic-encapsulated into a plastic-coated rotor after the end and / or internal gaps are filled with encapsulating material. At least one non-filled portion is provided on the axial end face of at least one end of the plastic-coated rotor, and the non-filled portion is not filled with encapsulating material.

[0026] By simultaneously incorporating a first permanent magnet and a second permanent magnet in the rotor, the first and second permanent magnets jointly provide magnetic flux to the motor, thereby increasing the motor's output power. The design of the relative positions of the first and second permanent magnets, with the first permanent magnet inserted into the groove of the second permanent magnet, allows the first permanent magnet to serve as part of the magnetic flux path of the second permanent magnet, drawing the magnetic flux lines of the second permanent magnet into the rotor core. After the magnetic flux lines of the first and second permanent magnets are magnetized on the rotor core, they then enter the air gap and stator, significantly improving the rotor's magnetization effect. Furthermore, apart from the rotor core, no other magnetically conductive components are present in the rotor structure, resulting in fewer parts, fewer assembly steps, simpler assembly, and lower production costs. Simultaneously, the axial end leakage magnetic flux lines of the first permanent magnet need to form a closed loop through the second permanent magnet. The non-magnetically conductive second permanent magnet weakens the end leakage magnetic flux of the first permanent magnet, and the flow direction of the magnetic flux lines of the second permanent magnet is opposite to that of the end leakage magnetic flux lines of the first permanent magnet, creating a mutual repulsion effect. This further reduces the axial end leakage magnetic flux of the first permanent magnet, increasing the rotor's magnetic field strength. After the rotor structure is filled with molding compound at the ends and / or internal gaps to form a plastic-coated rotor, the overall strength of the rotor structure can be enhanced. To achieve polarity positioning of the rotor assembly during the plastic coating process, at least one unfilled portion is provided on the axial end face of at least one end of the plastic-coated rotor; this unfilled portion is not filled with molding compound. Furthermore, the unfilled portion can reduce the shrinkage of the molding compound at the axial end of the plastic-coated rotor, which is more conducive to the molding of the plastic-coated rotor. Attached Figure Description

[0027] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0028] Figure 1 A perspective structural diagram of a plastic-coated rotor according to an embodiment of the present invention is shown;

[0029] Figure 2 A partially exploded structural diagram of a plastic-coated rotor according to an embodiment of the present invention is shown;

[0030] Figure 3 An exploded structural diagram of a plastic-coated rotor according to an embodiment of the present invention is shown;

[0031] Figure 4 A top view of the plastic-coated rotor according to an embodiment of the present invention is shown;

[0032] Figure 5 It shows Figure 4 Sectional view along axis AA;

[0033] Figure 6 A side view of the plastic-coated rotor according to an embodiment of the present invention is shown;

[0034] Figure 7 It shows Figure 6 BB-direction sectional view;

[0035] Figure 8 It shows Figure 6 CC-direction sectional view;

[0036] Figure 9 It shows Figure 6 DD section view;

[0037] Figure 10 A perspective structural diagram of a rotor structure according to an embodiment of the present invention is shown;

[0038] Figure 11 A partially exploded structural diagram of a rotor structure according to an embodiment of the present invention is shown;

[0039] Figure 12 A top view of a second permanent magnet according to an embodiment of the present invention is shown;

[0040] Figure 13 A perspective structural diagram of a rotor structure according to an embodiment of the present invention is shown;

[0041] Figure 14 A partially exploded structural diagram of a rotor structure according to an embodiment of the present invention is shown;

[0042] Figure 15 A top view of a rotor structure according to an embodiment of the present invention is shown;

[0043] Figure 16 A cross-sectional view of a rotor structure according to an embodiment of the present invention is shown;

[0044] Figure 17 A top view schematic diagram of a portion of the rotor structure according to an embodiment of the present invention is shown;

[0045] Figure 18 A side view of the motor according to an embodiment of the present invention is shown;

[0046] Figure 19 A perspective structural diagram of a rotor structure according to an embodiment of the present invention is shown;

[0047] Figure 20 A partially exploded structural diagram of a rotor structure according to an embodiment of the present invention is shown;

[0048] Figure 21 A top view of a second permanent magnet according to an embodiment of the present invention is shown;

[0049] Figure 22 A schematic diagram showing the polarity direction of the rotor structure of the present invention is shown;

[0050] Figure 23 A schematic diagram of the magnetic circuit of the rotor structure of the present invention is shown;

[0051] Figure 24 A comparison diagram of the magnetic flux density of a motor according to an embodiment of the present invention and a motor of related technologies is shown;

[0052] Figure 25 A comparison diagram of the leakage flux coefficients of a motor according to an embodiment of the present invention and a motor of related technologies is shown;

[0053] Figure 26 A comparison diagram of the no-load magnetic flux of a motor according to an embodiment of the present invention and a motor of related technologies is shown;

[0054] Figure 27 A comparison diagram of the air gap magnetic flux density of a motor according to an embodiment of the present invention and a motor of the related art is shown;

[0055] Figure 28 A comparison diagram of the torque-current characteristics of a motor according to an embodiment of the present invention and a motor of related technologies is shown; and

[0056] Figure 29 A comparison diagram of torque ripple between a motor according to an embodiment of the present invention and a motor of the related art is shown.

[0057] The above figures include the following reference numerals:

[0058] 11. Rotor core; 111. Limiting protrusion; 112. Opening slot; 113. Through hole; 12. First permanent magnet; 21. Second permanent magnet; 211. Hole structure; 212. Marking part; 213. Groove; 214. Protrusion; 215. Countersunk hole part; 216. Countersunk groove part; 217. Window; 31. Stator core; 4. Plastic-coated rotor; 41. Non-filled part; 42. Plastic sealant. Detailed Implementation

[0059] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0060] See also Figures 1 to 23As 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 disposed at the axial end of the rotor core 11. A groove 213 is provided on the second permanent magnet 21, and a protrusion 214 is formed between adjacent grooves 213. The portion of the first permanent magnet 12 extending axially out of the rotor core 11 is inserted into the groove 213. The first permanent magnet 12 is magnetized along the radial direction and / or tangential direction of the rotor core 11, and the second permanent magnet 21 is magnetized along the axial direction of the rotor core 11.

[0061] like Figure 23 As shown, a first permanent magnet 12 and a second permanent magnet 21 are simultaneously arranged in the rotor. The first permanent magnet 12 and the second permanent magnet 21 together provide magnetic flux to the motor, which can increase the output power of the motor. The relative positions of the first permanent magnet 12 and the second permanent magnet 21 are designed so that the first permanent magnet 12 is inserted into the groove 213 of the second permanent magnet 21. The first permanent magnet 12 serves as part of the magnetic circuit for the magnetic lines of force of the second permanent magnet 21, pulling the magnetic lines of force of the second permanent magnet 21 into the rotor core 11. The magnetic lines of force of the first permanent magnet 12 and the second permanent magnet 21 are on the rotor core 11. After being magnetized, the magnetic flux enters the air gap and stator, which can significantly improve the magnetization effect of the rotor. In addition, apart from the rotor core 11, no other magnetically conductive components are set in the rotor structure. The leakage magnetic field lines at the axial end of the first permanent magnet 12 need to form a closed loop through the second permanent magnet 21. The non-magnetically conductive second permanent magnet 21 weakens the leakage magnetic flux at the end of the first permanent magnet 12. Moreover, the flow direction of the magnetic field lines of the second permanent magnet 21 is opposite to the flow direction of the leakage magnetic field lines at the end of the first permanent magnet 12, resulting in a mutual repulsion effect. This will further reduce the leakage magnetic flux at the axial end of the first permanent magnet 12 and increase the rotor magnetic field strength.

[0062] The design of the first permanent magnet 12 and the second permanent magnet 21 in the rotor structure provides a return magnetic path for the magnetic flux of the second permanent magnet 21 through the first permanent magnet 12. There is no need to add an additional magnetic end plate to cooperate with the magnetic path of the second permanent magnet 21. This eliminates the dependence of the second permanent magnet 21 on the magnetic end plate. At the same time, it reduces the number of rotor parts, resulting in fewer assembly steps, simpler assembly, and lower production costs.

[0063] In one embodiment, the first permanent magnet 12 is magnetized along the radial and / or tangential direction of the rotor core 11, and the second permanent magnet 21 is magnetized along the axial direction of the rotor core 11. The magnetic lines of force entering the rotor core 11 from different directions create a magnetic focusing effect on the rotor core 11, increasing the rotor magnetic field strength and simultaneously increasing the utilization rate of the rotor core 11.

[0064] like Figure 23As shown, in this embodiment, the first permanent magnet 12 with a larger axial height is configured to be tangentially magnetized, and the second permanent magnet 21 located at the axial end of the rotor core 11 is configured to be axially magnetized. This enables the continuity of the magnetic flux of the first permanent magnet 12 and the second permanent magnet 21, allowing them to more effectively provide magnetic flux to the motor and effectively increase the motor output.

[0065] In one embodiment, the first permanent magnet 12 is a combined magnet design of tangential magnetization and radial magnetization.

[0066] In one embodiment, the magnetization direction of the second permanent magnet 21 is not limited to being parallel to the axial direction of the rotor core 11, but can also be at an acute angle to the axial direction of the rotor core 11.

[0067] In one embodiment, the second permanent magnet 21 is provided with a hole structure 211. The shape of the hole structure is not limited to circular, elliptical, square or other shapes.

[0068] In one embodiment, a projection is made on one end face of the rotor core 11 along the axial direction of the rotor core 11. Within this projection plane, the shape of the hole structure 211 on the second permanent magnet 21 matches the shape of the rotor core 11 at the corresponding position. The magnetic lines of force of the second permanent magnet 21 enter the rotor core 11 after being guided by the end face of the rotor core 11, becoming the main magnetic field. The matching of the shape of the hole structure 211 with the shape of the rotor core 11 at the corresponding position can improve the assembly accuracy of the second permanent magnet 21 and the rotor core 11, making the second permanent magnet 21 more effectively become the main magnetic flux through the magnetic guidance of the rotor core 11, improving the utilization rate of the second permanent magnet 21 and the rotor core 11. At the same time, the reasonable design of the position and shape of the hole structure 211 can guide the magnetic field of the second permanent magnet 21, ensuring the uniformity and unsaturation of the magnetic field distribution of the rotor core 11, and reducing rotor iron loss.

[0069] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the hole structure 211 on the second permanent magnet 21 is located near the radial inner side of the second permanent magnet 21. The hole structure 211 organizes and guides the magnetic lines of force on the radial inner side of the second permanent magnet 21, thereby limiting the area of ​​action of the magnetic lines of force of the second permanent magnet 21.

[0070] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the length of the line connecting the center of the hole structure 211 and any point on the end edge of the second permanent magnet 21 near the shaft is Di4, and the length of the line connecting the center of the hole structure 211 and any point on the end edge of the second permanent magnet 21 near the air gap is Di5, min(Di4)≤min(Di5), preferably, min(Di4)<min(Di5), further restricting the position of the hole structure 211, giving full play to its role in organizing and guiding the magnetic lines of force of the second permanent magnet 21, thereby reducing the repulsive force of the second permanent magnet 21 on the first permanent magnet 12, and reducing the difficulty of assembly and manufacturing.

[0071] In one embodiment, the second permanent magnet 21 has a countersunk hole 215, which is located on the end face of the second permanent magnet 21 on the side away from the rotor core 11. On one hand, the countersunk hole 215 can change the magnetic reluctance of the second permanent magnet 21 when its magnetic flux short-circuits itself; the increased air magnetic reluctance at the countersunk hole 215 weakens the ineffective self-short-circuit magnetic flux of the second permanent magnet 21. On the other hand, the countersunk hole 215 can be used for positioning during the manufacturing and assembly process of the second permanent magnet 21, simplifying the manufacturing and assembly process. Furthermore, by placing the countersunk hole 215 on the end face of the second permanent magnet 21 on the side away from the rotor core 11, the countersunk hole 215 does not affect the surface area of ​​the magnetizing surface of the second permanent magnet 21 that directly contacts the rotor core 11, maximizing the utilization of the magnetic flux of the second permanent magnet 21.

[0072] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the countersunk portion 215 is located radially outside the hole structure 211 to increase the effect of the countersunk portion 215 on the radially outer magnetic flux of the second permanent magnet 21, further weaken the self-short-circuit magnetic flux of the second permanent magnet 21, and improve the magnetic flux utilization rate of the second permanent magnet 21.

[0073] In one embodiment, the second permanent magnet 21 is provided with a groove 216, which is located on the end face of the second permanent magnet 21 near the rotor core 11. On the one hand, the groove 216 can reduce the volume of raw materials used in the second permanent magnet 21, thereby reducing the material cost of the second permanent magnet 21; on the other hand, the groove 216 can be used for positioning the second permanent magnet 21 during the molding process, reducing the molding difficulty of the second permanent magnet 21.

[0074] In one embodiment, the recess 216 is disposed on the groove 213 of the second permanent magnet 21 so that the recess 216 does not affect the area of ​​the magnetizing surface of the second permanent magnet 21.

[0075] In one embodiment, a marking portion 212 is provided on the second permanent magnet 21. The marking portion 212 is used to identify the polarity order of the second permanent magnet 21, and the marking portion 212 is not limited to letter marking, shape marking or other forms of marking.

[0076] In one embodiment, the marking portion 212 is disposed on the end face of the second permanent magnet 21 on the side near and / or away from the rotor core 11. Preferably, the marking portion 212 is disposed on the end face of the second permanent magnet 21 on both the side near and away from the rotor core 11, that is, the marking portion is disposed on both axial end faces of the second permanent magnet 21, which facilitates the identification of the polarity of the second permanent magnet 21.

[0077] In one embodiment, the marking portion 212 is disposed in the adjacent area of ​​a hole structure 211. The cooperation between the marking portion 212 and the hole structure 211 ensures the uniqueness of the polarity sequence of the second permanent magnet 21 after it is magnetized.

[0078] In one embodiment, the second permanent magnet 21 has at least two hole structures 211 to ensure the symmetry of the rotor magnetic field and reduce torque pulsation and harmonic losses caused by magnetic field asymmetry. Preferably, the second permanent magnet 21 has p or 2p hole structures 211, and the rotor core 11 has through holes 113, with at least one hole structure 211 and at least one through hole 113 extending along the axial direction of the rotor core 11. Most preferably, the second permanent magnet 21 has 2p hole structures 211, with the 2p hole structures 211 and 2p through holes 113 extending along the axial direction of the rotor core 11.

[0079] In one embodiment, a rivet is built into the hole structure 211. The rivet passes through the hole structure 211 on the second permanent magnet 21 and enters the rotor core 11. It extends from the other end face of the rotor assembly and is riveted and fastened to achieve the assembly of the rotor assembly.

[0080] In one embodiment, the second permanent magnet 21 is an injection-molded magnet. Using injection-molded magnets can reduce rotor saturation and iron loss; on the other hand, injection-molded magnets have higher shape freedom, which can reduce the manufacturing difficulty of the second permanent magnet 21 and the rotor structure.

[0081] In one embodiment, the second permanent magnet 21 is injection-molded ferrite or injection-molded neodymium iron boron, and the second permanent magnet 21 can also be injection-molded magnet of other material types.

[0082] In one embodiment, at least one end of the axial end of the rotor core 11 is provided with a second permanent magnet 21, and the number of second permanent magnets 21 provided in the rotor structure is not less than one. Preferably, the number of second permanent magnets 21 provided in the rotor structure is two, that is, second permanent magnets 21 are provided at both axial ends of the rotor core 11, thereby enabling the magnetic circuit at the motor end to be sorted out, resulting in greater torque density, higher motor efficiency, and ensuring high motor performance. Along the axial direction of the rotor core 11, the rotor core 11 and the second permanent magnets 21 are attached together to reduce the loss of magnetic flux in the second permanent magnets 21 during flow. It should be noted that the single second permanent magnet 21 here refers to all the second permanent magnets 21 located on a certain axial plane at the axial end of the rotor core 11. However, the single second permanent magnet 21 is not limited to an integral structure or a segmented structure.

[0083] In one embodiment, when the single second permanent magnet 21 has a segmented structure, the number of its segments is not limited to two or more.

[0084] In one embodiment, the second permanent magnet 21 cooperates with the first permanent magnet 12 through a groove 213 provided thereon. Both the first permanent magnet 12 and the second permanent magnet 21 are magnetic flux sources. Apart from the rotor core 11, no other magnetic conductive components are provided in the rotor structure.

[0085] In one embodiment, the grooves 213 on the second permanent magnet 21 do not penetrate the second permanent magnet 21. The number of grooves 213 is the same as the number of rotor poles, and protrusions 214 are formed between adjacent grooves 213. Because the grooves 213 do not penetrate the second permanent magnet 21, the second permanent magnet 21 is a single unit. Figure 14 As shown, in one embodiment of the present invention, a protrusion 214 is formed between two adjacent grooves, and the outer and inner sides of the two adjacent protrusions 214 are disconnected, which can reduce the processing difficulty of the second permanent magnet 21 and reduce the processing cost. In another embodiment of the present invention, a protrusion 214 is formed between two adjacent grooves 213, and the outer side of the two adjacent protrusions 214 is 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 the magnetic bridge saturate, reducing the leakage magnetic flux of the first permanent magnet 12 at the inner magnetic bridge. In another embodiment of the present invention, a protrusion 214 is formed between two adjacent grooves 213, and the outer side of the two adjacent protrusions 214 is connected, while the inner side is disconnected, which can increase the strength of the outer circle side of the second permanent magnet 21 on the one hand, and reduce the leakage magnetic flux on the inner hole side of the rotor on the other hand. In another embodiment of the present invention, in order to ensure the overall strength of the second permanent magnet 21, the outer side of the two adjacent protrusions 214 is connected, and the inner side is also connected.

[0086] In one embodiment, a polar region of the protrusion 214 corresponds to a polar region of the rotor core 11. That is, a polar region of the protrusion 214 of the second permanent magnet 21 generates magnetic flux, and a corresponding polar region of the rotor core 11 forms the magnetic path of this magnetic flux. The corresponding arrangement of the two can shorten the magnetic path as much as possible and reduce magnetic loss.

[0087] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the shape of a polar region of the protrusion 214 is adapted to the shape of a corresponding polar region of the rotor core 11, and the polar region of the protrusion 214 completely fills the corresponding polar region of the rotor core 11. Here, "completely fills" means that there is no gap between the protrusion 214 and the rotor core 11 on the plane perpendicular to the axial direction of the rotor core 11.

[0088] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the radial width of the second permanent magnet 21 is c1, the radial width of the groove 213 is c2, and the radial width of the protrusion 214 is c3. Then, 0.3≤min(c2) / max(c1)≤1, 0≤min(c3) / max(c1)≤1, and preferably, 0.7≤min(c2) / max(c1)≤0.95. That is, the groove 213 and the protrusion 214 can have radial widths that are not equal to those of the second permanent magnet 21. The appropriate radial widths of the groove and the protrusion can be selected according to the assembly requirements and the rotor saturation degree. If the rotor saturation degree is too high, a smaller c3 / c1 value can be selected; if it is necessary to reduce the assembly difficulty, a smaller c2 / c1 value can be selected. It should be noted that the "radial width of the second permanent magnet 21" in this invention is defined as the distance between two points on a plane perpendicular to the axial direction of the rotor core 11, where the line connecting the rotor's central axis and any point on the rotor's outer circle intersects the second permanent magnet 21. The definition of the "radial width" of other components or structures is similar.

[0089] In one embodiment, a projection is made onto one end face of the rotor core 11 along the axial direction of the rotor core 11, and within this projection plane, the radial width of the groove 213 is smaller than the radial width of the protrusion 214. For example... Figure 12 and Figure 21 As shown, two adjacent protrusions are connected by a groove. The radial width of the groove in the second permanent magnet is smaller than the radial width of the protrusion. This reduces the self-short circuit caused by the magnetic lines of force of the protrusion passing through the groove, improving the utilization rate of the second permanent magnet. Furthermore, the smaller radial width of the groove ensures that the magnetic lines of force of the protrusion can only selectively enter the rotor core, becoming effective magnetic flux, further improving the utilization rate of the second permanent magnet. In addition, the smaller portion of the groove compared to the protrusion allows the first permanent magnet and the rotor core, corresponding to their positions along the rotor axial direction, to be directly exposed on the rotor end face, which is more conducive to the assembly and positioning of the rotor assembly or the encapsulation of the rotor structure.

[0090] In one embodiment, the length of the line connecting the rotor central axis and any point on the end edge of the groove 213 near the air gap is Do5, and the length of the line connecting the rotor central axis and any point on the end edge of the protrusion 214 near the air gap is Do6. Then max(Do5) < max(Do6) to reduce the self-short-circuit leakage flux of the protrusion 214 near the air gap.

[0091] In one embodiment, the length of the line connecting the rotor central axis and any point on the end edge of the groove 213 near the shaft side is Di6, and the length of the line connecting the rotor central axis and any point on the end edge of the protrusion 214 near the shaft side is Di7. Then max(Di6)≥min(Di7) to reduce the self-short-circuit leakage flux of the protrusion 214 near the shaft side.

[0092] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the radial width of the groove 213 is c2, and the radial width of the protrusion 214 is c3. Therefore, 0.3 ≤ min(c2) / max(c3) < 1. More preferably, 0.55 ≤ min(c2) / max(c3) ≤ 0.98. Most preferably, 0.7 ≤ min(c2) / max(c3) ≤ 0.95. Limiting the ratio of the radial width of the groove 213 to the radial width of the protrusion 214 ensures that the groove 213 weakens the self-short-circuit leakage magnetic flux of the protrusion 214 without affecting the magnetic flux of the second permanent magnet 21, effectively improving the utilization rate of the second permanent magnet 21.

[0093] In one embodiment, on the outer circumference of the second permanent magnet 21 near the air gap side, on a plane perpendicular to the axial direction of the rotor core 11, the groove 213 has a tangential dimension of d1 and the protrusion 214 has a tangential dimension of d2, then d1 / d2 ≥ 0.2. Limiting the minimum value of d1 / d2 can reduce the saturation of the rotor core 11 and increase the flux utilization of the second permanent magnet 21.

[0094] In one embodiment, the first permanent magnet 12 and the second permanent magnet 21 are divided into multiple polarity regions after being magnetized. The first permanent magnet 12 is alternately magnetized with its N and S poles along the radial and / or tangential directions of the rotor core 11; the second permanent magnet 21 is alternately magnetized with its N and S poles along the axial direction of the rotor core 11.

[0095] The polarity of the side of the second permanent magnet 21 closest to the rotor core 11 is the first polarity. The polarity of the two first permanent magnets 12 adjacent to the second permanent magnet 21 on the side closest to the rotor core 11 is also the first polarity. That is, the polarity of the side of the second permanent magnet 21 closest to the rotor core 11 is the same as the polarity of the side of the two first permanent magnets 12 adjacent to the second permanent magnet 21 closest to the rotor core 11. Figure 22 In the embodiment shown, the second permanent magnet 21 is axially magnetized and the first permanent magnet 12 is tangentially magnetized. At a certain pole, the magnetization direction of both points to the rotor core 11. Under this magnetization method, the magnetic flux of the first permanent magnet 12 and the second permanent magnet 21 can be superimposed, thereby increasing the unloaded magnetic flux.

[0096] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the area of ​​a polar region of the second permanent magnet 21 is s1, and along the axial direction of the rotor core 11, the area of ​​the outer surface of the rotor core 11 is s2. Then, 0.2≤2p*s1 / s2≤2.2, where p is the number of rotor pole pairs. The second permanent magnet 21 is the magnetic flux source, and the rotor core 11 is the magnetically conductive structure. The magnetic flux of the second permanent magnet 21 passes through the rotor core 11 and the air gap in sequence before entering the stator side. The outer surface of the rotor core 11 is directly connected to the air gap. Limiting the minimum value of the magnetic supply area of ​​the second permanent magnet 21 and the outer surface area of ​​the rotor core 11 ensures that the rotor core 11 can carry a certain amount of magnetic flux from the second permanent magnet 21, thus improving the utilization rate of the rotor core 11. Limiting the maximum value of the magnetic supply area of ​​the second permanent magnet 21 and the outer surface area of ​​the rotor core 11 limits the maximum magnetic flux of the second permanent magnet 21 carried by the rotor core 11, reduces the saturation degree of the rotor core 11, and reduces losses.

[0097] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the area of ​​one polar region of the rotor core 11 is s6, the area of ​​one polar region of the second permanent magnet 21 is s1, and along the axial direction of the rotor core 11, the area of ​​one polar region of the first permanent magnet 12 is s5. Therefore, 2 ≤ (s1 + s5) / s6 ≤ 10. It should be noted that s5 refers to the area of ​​the magnetic supply surface of one polar region of the first permanent magnet 12. The rotor core 11 carries the magnetic flux of both the second permanent magnet 21 and the first permanent magnet 12. Limiting the ratio of the sum of the magnetic supply surface areas of the first and second permanent magnets 21 to the axial magnetic guide surface area of ​​the rotor core 11 improves the utilization rate of the rotor core 11 while ensuring that the rotor core 11 has a suitable degree of saturation.

[0098] 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 second permanent magnet 21 is z1, and the axial height of the protrusion 214 is z2, where 0.2*(yx)≤z1≤1.6*(yx).

[0099] In one embodiment, 2*z2≥(yx) can avoid interference between the first permanent magnet 12 and the second permanent magnet 21, so as to realize the assembly of the first permanent magnet 12 and the second permanent magnet 21.

[0100] In one embodiment, z2 = 0.5*(yx) can form an optimal fit, effectively avoiding the gap between the first permanent magnet 12 and the second permanent magnet 21, and reducing magnetic loss.

[0101] In one embodiment, 0.03≤(z1-z2) / z1≤0.7 allows the portion of the groove 213 that does not penetrate the second permanent magnet 21 to have a certain axial thickness proportion in the second permanent magnet 21, so as to ensure the structural strength of the second permanent magnet 21.

[0102] In one embodiment, along the axial direction of the rotor core 11, the axial height of the second permanent magnet 21 is z1, the axial height of the rotor core 11 is x, and the axial height of the groove 213 is z3. Therefore, 0.2 ≤ z3 / z1 ≤ 1, and 0.05 ≤ z3 / x ≤ 0.6. Limiting the z3 / z1 ratio ensures that the groove 213 has a certain axial height, simplifying the assembly process of each rotor component. Limiting the z3 / x ratio ensures that each flux source has a suitable ratio, guaranteeing that the rotor has a suitable degree of saturation. A suitable flux source ratio also helps improve the torque linearity of the motor.

[0103] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the length of the line connecting the rotor central axis and any point on the end edge of the second permanent magnet 21 near the shaft side is Di2, the inner diameter of the rotor core 11 is Di1, and min(Di2)≥0.5*Di1, preferably, min(Di2)≥1.2*Di1. A shaft needs to be installed in the inner hole of the rotor core 11. The above dimensional relationship allows for space for the shaft installation; furthermore, without affecting the shaft installation, the inner hole of the second permanent magnet 21 can be filled with molding compound or other materials to enhance rotor strength.

[0104] In one embodiment, min(Di2) = 0.5*Di1, that is, the inner diameter of the second permanent magnet 21 is the same as the inner diameter of the rotor core 11, which can increase the magnetizing surface of the second permanent magnet 21 and improve the magnetic flux contribution of the second permanent magnet 21.

[0105] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the length of the line connecting the rotor central axis to any point on the end edge of the second permanent magnet 21 near the shaft is Di2, and the length of the line connecting the rotor central axis to the center of the end edge of one pole of the first permanent magnet 12 near the shaft is Di3, where max(Di2) ≥ 0.75 * Di3. Preferably, max(Di2) ≥ Di3. Most preferably, min(Di2) ≥ Di3. Near the shaft, on the one hand, the magnetic circuit area of ​​the rotor core 11 is too small, and the core is easily saturated; on the other hand, the permanent magnet at this location contributes little to the torque, resulting in low utilization of the permanent magnet. Therefore, limiting the relationship between Di2 and Di3 can improve the utilization rate of the second permanent magnet 21 while reducing the saturation degree of the rotor core 11 and reducing losses. In addition, limiting the positional relationship between the second permanent magnet and the first permanent magnet near the shaft can also limit the effective area of ​​the magnetic flux of the second permanent magnet and the effective area of ​​the magnetic flux of the first permanent magnet, weaken the repulsive force between the second permanent magnet and the first permanent magnet, and reduce the assembly difficulty.

[0106] In one embodiment, the second permanent magnet 21 has an outer peripheral surface near the air gap side and an inner peripheral surface near the shaft side, and at least one window 217 is provided on the outer peripheral surface and / or the inner peripheral surface of the second permanent magnet 21. Figures 19-21 In the embodiment shown, windows 217 are provided on both the outer and inner peripheral surfaces of the second permanent magnet 21; as shown Figures 10-15 In the illustrated embodiment, a window 217 is provided on the outer peripheral surface of the second permanent magnet 21. Each end edge of the window 217 is a straight line, an arc, or any combination of straight lines and arcs. Providing windows on the outer peripheral surface of the second permanent magnet near the air gap side and / or the inner peripheral surface near the shaft side can limit the effective area of ​​the magnetic flux of the second permanent magnet, allowing it to have a suitable magnetic field strength near the air gap side or near the shaft side, weakening the repulsive force of the second permanent magnet on the first permanent magnet, and reducing assembly difficulty. Furthermore, the window can also serve as a positioning structure during rotor assembly, improving assembly accuracy.

[0107] In one embodiment, preferably, the window 217 is disposed on the outer peripheral surface of the second permanent magnet 21. The magnetic supply area of ​​the second permanent magnet 21 near the outer peripheral surface is large, and the magnetic conduction area of ​​the rotor core 11 is large and the magnetic field strength is large. Distributing the window 217 on its outer peripheral surface helps to limit the magnetic flux action area of ​​the second permanent magnet 21 and improves the utilization rate of the second permanent magnet 21.

[0108] In one embodiment, a limiting protrusion 111 is provided on the outer periphery of the rotor core 11. The limiting protrusion 111 extends laterally from both sides of the rotor core 11 in the circumferential direction and forms a radial limit on the first permanent magnet 12. An opening groove 112 is formed between the limiting protrusion 111 and the first permanent magnet 12. The opening groove 112 and the window 217, which are correspondingly provided in the circumferential direction, are connected in the axial direction of the rotor core 11. The window 217 and the opening groove 112, which are connected in the axial direction, are used together as a positioning structure when the second permanent magnet 21 is assembled to the rotor core 11, which can improve the assembly accuracy.

[0109] like Figure 17 As shown, the limiting protrusion 111 is located at the outermost periphery of the rotor core 11 and extends circumferentially from two sides of the rotor core 11 in the circumferential direction. The two limiting protrusions 111 extending in opposite directions are spaced apart, thereby forming an opening groove 112 while radially limiting the first permanent magnet 12, reducing the radial magnetic leakage of the first permanent magnet 12.

[0110] In one embodiment, the window 217 is disposed on the groove 213 to minimize the impact of the window 217 on the magnetic supply area of ​​the second permanent magnet 21, thereby ensuring that the second permanent magnet 21 has a suitable magnetic flux contribution.

[0111] In one embodiment, window 217 is disposed on the inner circumferential surface of the second permanent magnet 21. In order to reduce the bottom magnetic leakage of the first permanent magnet 12 near the shaft, a magnetic isolation hole is provided between the rotor core 11 and the side of the first permanent magnet 12 near the shaft, and the window 217 and the magnetic isolation hole are connected along the axial direction of the rotor assembly.

[0112] In one embodiment, a projection is made onto one end face of the rotor core 11 along its axial direction. Within this projection plane, the position of the window 217 on the second permanent magnet 21 coincides with the position of the first permanent magnet 12. This arrangement further restricts the position of the window 217 on the circumference and radial direction of the second permanent magnet 21, making the position of the window 217 correspond to the position of the first permanent magnet 12. This weakens the repulsive force between the second permanent magnet 21 and the first permanent magnet 12, reducing assembly difficulty. Simultaneously, the window 217 organizes the magnetic flux of the second permanent magnet 21, allowing it to enter the end face of the rotor core 11 more effectively, thus improving the utilization rate of the second permanent magnet 21.

[0113] In one embodiment, a projection is made onto one end face of the rotor core 11 along its axial direction. Within this projection plane, the second permanent magnet 21 has a portion that does not overlap with the first permanent magnet 12, and the first permanent magnet 12 is exposed outside the second permanent magnet 21. That is, the second permanent magnet 21 does not completely cover the end of the first permanent magnet 12; from the rotor end face, the end of the first permanent magnet 12 has an exposed portion. This arrangement is also to allow the magnetic lines of force of the second permanent magnet 21 to enter the end face of the rotor core 11 more effectively, thereby improving the utilization rate of the second permanent magnet 21.

[0114] In one embodiment, a projection is made onto one end face of the rotor core 11 along the axial direction. Within this projection plane, the area of ​​a window 217 on the second permanent magnet 21 is s7, and the area of ​​a polar region of the second permanent magnet 21 is s1. Then, 0.04 ≤ s7 / s1 ≤ 0.32. Limiting the area ratio between the window 217 and the second permanent magnet 21 serves two purposes: firstly, it ensures that the window 217 has a certain area, allowing it to better perform its function of magnetic flux alignment and positioning; secondly, it limits the maximum area ratio of the window 217 to avoid its influence on the magnetic flux supply surface of the second permanent magnet 21.

[0115] In one embodiment, a projection is made on one end face of the rotor core 11 along the axial direction. Within this projection plane, the area of ​​a window 217 on the second permanent magnet 21 is s7, the area of ​​a groove 213 in a polar region of the second permanent magnet 21 is s8, and the area of ​​a protrusion 214 in a polar region of the second permanent magnet 21 is s9. Then, 0.08 ≤ s7 / s8 ≤ 0.36, and 0.07 ≤ s7 / s9 ≤ 0.32. Similar to limiting the range of s7 / s1, by limiting the proportion of the area of ​​the window 217 in the area of ​​the groove 213, the window 217 is ensured to have a suitable area; by limiting the proportion of the area of ​​the window 217 in the area of ​​the protrusion 214, its influence on the magnetizing surface of the second permanent magnet 21 is avoided.

[0116] In one embodiment, a projection is made onto one end face of the rotor core 11 along the axial direction. Within this projection plane, the area of ​​a window 217 on the second permanent magnet 21 is s7, and the area of ​​the first permanent magnet 12 is s10. Then, 0.07 ≤ s7 / s10 ≤ 0.31. Limiting the range of s7 / s10 allows the window 217 to effectively weaken the repulsive force between the ends of the second permanent magnet 21 and the first permanent magnet 12, reducing assembly difficulty.

[0117] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the length of the line connecting the rotor central axis to any point on the end edge of the second permanent magnet 21 near the air gap is Do2; the length of the line connecting the rotor central axis to the center of the end edge of one pole of the first permanent magnet 12 near the air gap is Do3; and the length of the line connecting the rotor central axis to any point on the end edge of the groove 213 near the air gap is Do5. Then, 0.4 ≤ max(Do5) / max(Do2) < 1.0, 0.45 ≤ max(Do5) / Do3 ≤ 1.1. More preferably, 0.7 ≤ max(Do5) / max(Do2) ≤ 0.98. Most preferably, 0.85 ≤ max(Do5) / max(Do2) ≤ 0.96. After setting the window 217 on the groove 213, the length of the line connecting the rotor central axis and any point on the end edge of the groove 213 near the air gap side is reduced. By limiting this size, the groove 213 can be set with the window 217 in a suitable position, which further enhances the effect of the window 217 on the radial outer magnetic field lines of the second permanent magnet 21 and improves the utilization rate of the window 217.

[0118] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the length of the line connecting the rotor central axis and any point on the end edge of the second permanent magnet 21 near the air gap side is Do2, and the depth of the window 217 along its radial direction is H, then 0.03≤min(H) / max(Do2)≤0.6.

[0119] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the width of the first permanent magnet 12 along the tangential direction is L1, and the width of the window 217 along the tangential direction is L2, then 0.1≤min(L2) / max(L1)≤2.0. More preferably, 0.4≤min(L2) / max(L1)≤1.1.

[0120] like Figure 21 As shown, the radial depth H of window 217 refers to the distance between two points where the line connecting the rotor's central axis and any point on the outer circle of the second permanent magnet 21 intersects window 217 in a plane perpendicular to the axial direction of the second permanent magnet 21. The tangential width L2 of window 217 refers to the distance between the two ends of window 217 in a direction perpendicular to the radial direction in a plane perpendicular to the axial direction of the second permanent magnet 21. By limiting the value of H, the radial extension depth of window 217 is selected; by limiting the value of L2, the tangential extension dimension of window 217 is selected, ensuring that window 217 has a suitable position on the second permanent magnet 21, thus more effectively performing its function of magnetic flux alignment and positioning.

[0121] In one embodiment, 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 disposed at the axial end of the rotor core 11, and a groove 213 is provided on the second permanent magnet 21. The portion of the first permanent magnet 12 extending axially out of the rotor core 11 is inserted into the groove 213. The first permanent magnet 12 is magnetized along the radial and / or tangential direction of the rotor core 11, and the second permanent magnet 21 is magnetized along the axial direction of the rotor core 11. The second permanent magnet 21 has an outer peripheral surface near the air gap side and an inner peripheral surface near the shaft side. At least one window 217 is provided in the region near the outer peripheral surface and / or inner peripheral surface of the second permanent magnet 21, and the window 217 does not penetrate the outer peripheral surface and / or inner peripheral surface of the second permanent magnet 21 along the radial direction. The radial direction of the second permanent magnet 21 is a radial direction from the center of the second permanent magnet 21 to its outer circle. This arrangement ensures that the window 217 does not cut through the outer circle side and the inner hole side of the second permanent magnet 21. While retaining the magnetic flux arrangement and positioning function of the window 217, it can increase the structural strength of the second permanent magnet 21 and improve the reliability of motor operation.

[0122] In one embodiment, the outer peripheral wall of the rotor core 11 includes a plurality of spaced arc surfaces, and the distance between a single arc surface and the central axis of the rotor core 11 decreases from the middle to both ends along the circumferential direction. This arrangement allows a non-uniform thickness air gap structure to be formed between the outer peripheral wall of the rotor core 11 and the inner peripheral wall of the stator structure along the radial direction of the rotor, which can reduce the content of magnetic field harmonics, reduce motor torque pulsation, and weaken motor vibration noise.

[0123] In this embodiment, since the rotor core 11 forms an open slot 112, the outer periphery structure of the rotor core 11 is not a complete circle, but a number of spaced arc segments. The middle of each arc segment protrudes outward along the radial direction, forming an arc structure that is misaligned with the center of the outer circle of the rotor. This can improve the air gap magnetic flux density between the stator and rotor, which is more conducive to forming a sine curve and improving the working performance of the motor.

[0124] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the length of the line connecting the rotor central axis and any point on the end edge of the second permanent magnet 21 near the air gap is Do2, and the length of the line connecting the rotor central axis and any point on the end edge of the rotor core 11 near the air gap is Do1, and max(Do2)≤max(Do1).

[0125] In one embodiment, max(Do2) ≤ 0.98 * max(Do1).

[0126] For the motor, on the one hand, the stator structure is fitted outside the rotor structure, and an air gap is provided between the rotor structure and the stator structure. This arrangement allows space for the stator structure to be assembled. On the other hand, to ensure that the first permanent magnet 12 does 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 limiting protrusion 111 has a small magnetic circuit area and is easily saturated. Moreover, the limiting protrusion 111 is located close to the air gap, which is a magnetic flux accumulation point, resulting in high iron loss. Max(Do2) ≤ max(Do1) can ensure that the magnetic flux of the second permanent magnet 21 avoids the position of the limiting protrusion 111, thereby reducing the iron loss of the motor. In motors with a low iron loss ratio, max(Do2) = max(Do1) is a better choice. In motors with a high iron loss ratio, preferably, max(Do2) ≤ 0.98 * max(Do1). It should be noted that the end edge of the second permanent magnet 21 near the air gap is not limited to a full circle, a segmented circle, a combination of a circle and a straight line, a straight line, or other shapes.

[0127] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the length of the line connecting the rotor central axis and any point on the end edge of the second permanent magnet 21 near the air gap is Do2, and the length of the line connecting the rotor central axis and the center of the end edge of one pole of the first permanent magnet 12 near the air gap is Do3, max(Do2)≤1.2*Do3, and preferably, min(Do2)≤Do3.

[0128] In one embodiment, |max(Do2)-Do3|≤1.5mm.

[0129] By restricting the positional relationship between the first permanent magnet 12 and the second permanent magnet 21 near the air gap, the magnetic lines of force of the first permanent magnet 12 and the second permanent magnet 21 can have a better superposition effect near the air gap, thereby improving the air gap magnetic flux density.

[0130] 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 application of the motor, the operating temperature, etc.

[0131] In one embodiment, the intrinsic coercivity of the second permanent magnet 21 is lower than that of the first permanent magnet 12. Compared to the second permanent magnet 21 located at the axial end of the rotor core 11, the first permanent magnet 12 is embedded in the rotor core 11 and is directly affected by the stator demagnetizing magnetic field. Setting the intrinsic coercivity of the first permanent magnet 12 to be higher can enhance the motor's anti-demagnetizing ability.

[0132] In one embodiment, the ratio of the remanence of the second permanent magnet 21 to that of the first permanent magnet 12 ranges from 0.3 to 1.5. Preferably, the ratio ranges from 0.5 to 0.8. Using injection-molded magnets for the second permanent magnet 21 and sintered magnets for the first permanent magnet 12 is a preferred embodiment. Limiting the minimum remanence ratio of the two flux sources ensures a suitable flux proportion for the second permanent magnet 21, giving the motor a strong overload capacity. Limiting the maximum remanence ratio reduces the repulsive force between the second permanent magnet 21 and the first permanent magnet 12, thus reducing the assembly difficulty of the rotor assembly.

[0133] In one embodiment, the rotor core 11 is formed by stacking silicon steel sheets, or the rotor core 11 is an injection-molded magnet, and the N and N poles of the rotor core 11 are alternately magnetized in the radial direction on a plane perpendicular to the axial direction of the rotor core 11.

[0134] The rotor core 11 serves as the path carrier for the magnetic flux flow between the first permanent magnet 12 and the second permanent magnet 21, and plays a role in unblocking and guiding the magnetic flux.

[0135] In one embodiment, the rotor core 11 is made of stacked silicon steel sheets, which has better magnetic permeability.

[0136] In one embodiment, the rotor core 11 is an injection-molded magnet. After being magnetized, it has a traction effect on the magnetic flux of the first permanent magnet 12 and the second permanent magnet 21, and can also guide the magnetic flux to enter the air gap and stator after being magnetized.

[0137] In one embodiment, the second permanent magnet 21 is injection molded onto or filled onto the rotor core 11.

[0138] 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.

[0139] The second permanent magnet 21 and the first permanent magnet 12 can be manufactured in different ways, so the manufacturing method of the rotor can be selected according to the production conditions, thereby improving the flexibility of rotor structure production and manufacturing.

[0140] In one embodiment, the rotor structure is assembled and secured together using fasteners. The rotors can be fixed together by adhesive bonding, riveting, or other fastening methods, which simplifies the rotor manufacturing process and reduces production costs.

[0141] In one embodiment, the rotor structure is plastic-encapsulated into a plastic-coated rotor 4 after the end and / or internal gaps are filled with plastic sealant 42, which can ensure the overall structural strength of the rotor assembly. To achieve polarity positioning of the rotor assembly during the plastic-coating process, at least one unfilled portion 41 is provided on the axial end face of at least one end of the plastic-coated rotor 4. The unfilled portion 41 is not filled with plastic sealant 42. Furthermore, the unfilled portion 41 can reduce the shrinkage of the plastic sealant 42 at the axial end of the plastic-coated rotor, which is more conducive to the molding of the plastic-coated rotor.

[0142] In one embodiment, along the axial direction of the plastic-coated rotor 4, the unfilled portion 41 extends from the axial end face of the plastic-coated rotor 4 to the axial end face of the second permanent magnet 21 on the side away from the rotor core 11. That is, the second permanent magnet 21 is exposed outside the plastic sealant 42 at the axial end of the plastic-coated rotor 4. On the one hand, the plastic sealant 42 is divided by the unfilled portion 41, which can reduce the shrinkage of the plastic sealant 42 at the axial end; on the other hand, the unfilled portion 41 can serve as a support and positioning element during the plastic coating process of the rotor assembly. The number of unfilled portions 41 is not limited to one or more. Preferably, the number of unfilled portions 41 can be divided by 2p, where p is the number of pole pairs of the rotor. Most preferably, the number of unfilled portions 41 is p or 2p.

[0143] In one embodiment, a plurality of unfilled portions 41 are evenly distributed on one axial end face of the plastic-coated rotor 4. The shape of the unfilled portions 41 is not limited to cylindrical, frustum-shaped, three-dimensional trapezoidal, or any other shape composed of straight lines and / or arcs.

[0144] In one embodiment, a projection is made onto one end face of the plastic-coated rotor 4 along its axial direction. Within this projection plane, the unfilled portion 41 partially coincides with the protrusion 214 of the second permanent magnet 21. Preferably, the center of the unfilled portion 41 is located on the magnetic pole center line of the second permanent magnet 21 to ensure the structural symmetry of the plastic-coated rotor 4 and reduce the vibration and noise of the motor caused by the imbalance of the plastic-coated rotor 4.

[0145] In one embodiment, the second permanent magnet 21 is provided with a hole structure 211, and the rotor core 11 is provided with a through hole 113. At least one hole structure 211 and at least one through hole 113 are correspondingly provided and pass through the rotor core 11 in the axial direction. The hole structure 211 and the through hole 113 are filled with a molding compound 42 to enhance the connection strength between the second permanent magnet 21 and the rotor core 11.

[0146] In one embodiment, a projection is made on one end face of the plastic-coated rotor 4 along the axial direction of the rotor 4, and within this projection plane, the unfilled portion 41 is located radially outside the hole structure 211. For example... Figure 4As shown, D3 is the length of the line connecting the rotor's central axis to any point on the hole structure 211, and D4 is the length of the line connecting the rotor's central axis to any point on the non-filled part 41. Then, max(D4) ≥ max(D3). This restricts the relative position of the non-filled part 41 and the hole structure 211, effectively dividing the axial end molding compound 42 of the plastic-coated rotor 4 by the non-filled part 41, reducing the shrinkage of the end molding compound 42, ensuring the probability of successful plastic coating of the rotor assembly, and increasing the overall strength of the rotor.

[0147] In one embodiment, a projection is made on one end face of the plastic-coated rotor 4 along the axial direction. Within this projection plane, the area of ​​the overlapping portion of an unfilled portion 41 and a corresponding hole structure 211 is no greater than half the area of ​​the hole structure 211 at that position. Preferably, the area of ​​the overlapping portion of an unfilled portion 41 and a corresponding hole structure 211 is no greater than one-third the area of ​​the hole structure 211 at that position. Most preferably, there is no overlap between an unfilled portion 41 and a hole structure 211. The unfilled portion 41 can serve as a positioning support for the rotor assembly during the plastic coating process. It has an internal external tooling and is not filled with molding compound 42. The hole structure 211 serves as a flow path for the molding compound and is filled with molding compound. If there is an overlap between the two, the external tooling inside the unfilled portion 41 will block the molding compound flowing in the hole structure 211, reducing the probability of rotor plastic coating.

[0148] In one embodiment, along the axial direction of the plastic-coated rotor 4, the axial thickness of the encapsulating material 42 on the side of the plastic-coated rotor 4 where the non-filled portion 41 is provided is not greater than the axial thickness of the encapsulating material 42 on the side of the plastic-coated rotor 4 where the non-filled portion 41 is not provided. For example... Figure 5 As shown, D1 is the axial thickness of the encapsulant 42 on the side of the plastic-coated rotor 4 where the non-filled part 41 is provided, and D2 is the axial thickness of the encapsulant 42 on the side of the plastic-coated rotor 4 where the non-filled part 41 is not provided. D1≤D2, which can reduce the difficulty of filling the rotor with encapsulant 42 and make the plastic-coated rotor 4 easier to form.

[0149] In one embodiment, the radial width of the unfilled portion 41 is c4, and the radial width of the second permanent magnet 21 is c1, then 0.1 ≤ max(c4) / max(c1) ≤ 0.5. The maximum value of the radial width of the unfilled portion 41 is limited to ensure the strength of the encapsulant 42 at the axial end of the plastic-coated rotor 4.

[0150] In one embodiment, such as Figure 3 As shown, the plastic-coated rotor 4 has a stepped structure at the shaft hole where it is assembled with the rotating shaft to reinforce the connection.

[0151] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the length of the line connecting the rotor central axis and any point on the end edge of the second permanent magnet 21 near the air gap is Do2. After the rotor structure is filled with plastic sealant at the ends and internal gaps and plasticized into a whole, the length of the line connecting the rotor central axis and any point on the end edge of the rotor structure near the air gap is Do4. Then max(Do2)≤min(Do4) so ​​that the plastic sealant has a certain adhesion area and increases the overall strength of the rotor structure after plasticizing.

[0152] See also Figure 24 As shown, compared with motors of related technologies, the motor using the rotor structure of this invention has a magnetic flux density increased by more than 60%, and its magnetic flux density performance is significantly improved.

[0153] See also Figure 25 As shown, compared with motors of related technologies, the motor using the rotor structure of this invention has a leakage flux coefficient reduced by more than 10%, which effectively reduces leakage flux and improves motor performance.

[0154] See also Figure 26 As shown, compared with motors of related technologies, the motor using the rotor structure of this invention has an increase of more than 50% in no-load flux linkage, which effectively increases the no-load flux linkage and improves motor performance.

[0155] See also Figure 27 As shown, compared with motors of related technologies, the motor using the rotor structure of this invention has an air gap magnetic flux density increased by more than 60%, which effectively increases the air gap magnetic flux density, improves the motor torque density, and increases the motor output.

[0156] See also Figure 28 As shown, compared with motors of related technologies, the motor with the rotor structure of this invention has a torque multiplier that becomes increasingly apparent as the current increases, achieving a larger torque multiplier, improving the motor torque density, and increasing the motor output.

[0157] See also Figure 29 As shown, compared with motors of related technologies, the motor using the rotor structure of this invention reduces torque ripple by more than 30%, which significantly reduces electromagnetic vibration and noise of the motor.

[0158] According to an embodiment of the present invention, the motor includes a stator structure and a rotor structure, wherein the rotor structure is the rotor structure described above. The stator structure is sleeved on the outer periphery of the rotor structure.

[0159] In one embodiment, the axial height of the rotor core 11 is x; the stator structure includes a stator core 31, the axial height of which is w, and x ≥ w. Preferably, x ≥ 1.05 * w. In this invention, the end magnetic lines of force of the rotor core 11 can enter the rotor core 11 through magnetic guidance to become the main magnetic flux, without relying on the excessively high magnetic conduction of the stator core 31, and can also improve the rotor magnetic field strength. Therefore, limiting the relationship between x and w can improve the utilization rate of the stator core 31 and reduce the rotor saturation.

[0160] In one embodiment, the axial height of the rotor core 11 is x, the axial height of the stator core 31 is w, and the axial height of the second permanent magnet 21 is z1. Then, 0.2 ≤ z1 / x ≤ 0.8, 0.2 ≤ z1 / w ≤ 0.8, and 2.5 ≤ z1 / (xw) ≤ 10. The axial height of the second permanent magnet 21 is also one of the key parameters determining its magnetic flux strength. Limiting the values ​​of z1 / x and z1 / w can improve the utilization rate of the rotor and stator cores, and allow for the reasonable design of the thickness of the second permanent magnet 21 based on the core saturation level, resulting in a better magnetic flux strength. Furthermore, since the second permanent magnet 21 is located at the axial end of the rotor core 11, its magnetic lines of force must pass through the magnetic circuit at the end of the rotor core 11 before entering the stator. Limiting the ratio of z1 / (xw) ensures that the second permanent magnet 21 has a suitable magnetic circuit, reducing magnetic flux loss caused by magnetic reluctance.

[0161] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the area of ​​a polar region of the second permanent magnet 21 is s1, and the area of ​​the rotor core 11 above the outer surface of the stator core 31 along the axial direction of the rotor core 11 is s3. Therefore, 0.2 ≤ s1 / s3 ≤ 2.8. The second permanent magnet 21 is disposed at the axial end of the rotor core 11. Its magnetic lines of force must pass through the magnetic circuit at the end of the rotor core 11 before entering the stator, limiting the value of s1 / s3. This ensures that the end of the rotor core 11 has a suitable area to bear the magnetic flux of the second permanent magnet 21, thereby improving the rotor flux utilization rate.

[0162] In one embodiment, on a plane perpendicular to the axial direction of the rotor core 11, the area of ​​a polar region of the second permanent magnet 21 is s1, and the stator core 31 includes multiple stator teeth, with the area of ​​one stator tooth being s4. Therefore, 0.6 ≤ s1 / s4 ≤ 5.0. The stator teeth are an important part of the stator magnetic circuit, directly affecting the magnetic reluctance on the stator during magnetic flux flow. Limiting the value of s1 / s4 ensures, on the one hand, that the stator teeth have a suitable degree of saturation and high stator core utilization; on the other hand, it results in low stator magnetic circuit reluctance and high rotor magnetic flux utilization.

[0163] In one embodiment, the axial height of the rotor structure is v, and the axial height of the stator core 31 is w, where v ≥ 1.4 * w. Limiting the relationship between v and w can further improve the utilization rate of the stator core 31 while ensuring proper stator saturation.

[0164] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0165] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0166] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rotor structure, characterized in that, The rotor core (11) 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 disposed at the axial end of the rotor core (11), and a groove (213) is provided on the second permanent magnet (21). A protrusion (214) is formed between adjacent grooves (213). The portion of the body (12) extending axially out of the rotor core (11) is inserted into the groove (213). The first permanent magnet (12) is magnetized in the radial and / or tangential direction of the rotor core (11), and the second permanent magnet (21) is magnetized in the axial direction of the rotor core (11). The rotor structure is plastic-encapsulated into a plastic-coated rotor (4) after the end and / or internal gaps are filled with plastic sealant (42). At least one non-filled portion (41) is provided on the axial end face of at least one end of the plastic-coated rotor (4), and the non-filled portion (41) is not filled with plastic sealant (42).

2. The rotor structure according to claim 1, characterized in that, Along the axial direction of the plastic-coated rotor (4), the unfilled portion (41) extends from the axial end face of the plastic-coated rotor (4) to the axial end face of the second permanent magnet (21) on the side away from the rotor core (11).

3. The rotor structure according to claim 1, characterized in that, Multiple non-filled portions (41) are evenly distributed on one axial end face of the plastic-coated rotor (4).

4. The rotor structure according to claim 1, characterized in that, Projecting along the axial direction of the plastic-coated rotor (4) onto one end face of the plastic-coated rotor (4), in which the unfilled part (41) partially overlaps with the protrusion (214) of the second permanent magnet (21).

5. The rotor structure according to claim 1, characterized in that, The second permanent magnet (21) is provided with a hole structure (211), and the rotor core (11) is provided with a through hole (113). At least one hole structure (211) and at least one through hole (113) are provided and pass through the rotor core (11) in the axial direction.

6. The rotor structure according to claim 5, characterized in that, Projecting along the axial direction of the plastic-coated rotor (4) onto one end face of the plastic-coated rotor (4), in which the unfilled portion (41) is located radially outside the hole structure (211).

7. The rotor structure according to claim 6, characterized in that, The area of ​​the overlapping portion of one of the unfilled portions (41) and one of the hole structures (211) at the corresponding position is not greater than half the area of ​​the hole structure (211) at that position.

8. The rotor structure according to claim 3, characterized in that, Along the axial direction of the plastic-coated rotor (4), the axial thickness of the encapsulant (42) on the side of the plastic-coated rotor (4) where the non-filled portion (41) is provided is not greater than the axial thickness of the encapsulant (42) on the side of the plastic-coated rotor (4) where the non-filled portion (41) is not provided.

9. The rotor structure according to claim 1, characterized in that, Projecting a view of one end face of the rotor core (11) along the axial direction of the rotor core (11), in which the radial width of the groove (213) is smaller than the radial width of the protrusion (214).

10. The rotor structure according to claim 1, characterized in that, The second permanent magnet (21) has an outer peripheral surface near the air gap side and an inner peripheral surface near the shaft side, and at least one window (217) is provided on the outer peripheral surface and / or the inner peripheral surface of the second permanent magnet (21).

11. The rotor structure according to claim 10, characterized in that, The window (217) is disposed on the outer peripheral surface of the second permanent magnet (21); a limiting protrusion (111) is provided on the outer peripheral side of the rotor core (11), the limiting protrusion (111) extends laterally from both sides of the rotor core (11) in the circumferential direction and forms a radial limit on the first permanent magnet (12), an opening groove (112) is formed between the limiting protrusion (111) and the first permanent magnet (12), and the opening groove (112) and the window (217) disposed in the circumferential direction are connected in the axial direction of the rotor core (11).

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

13. The rotor structure according to claim 1, characterized in that, After being magnetized, the first permanent magnet (12) and the second permanent magnet (21) are divided into multiple polarity regions. The polarity of the side of the second permanent magnet (21) closest to the rotor core (11) is the first polarity. The polarity of the two first permanent magnets (12) on the sides adjacent to the second permanent magnet (21) is also the first polarity.

14. The rotor structure according to claim 1, 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 second permanent magnet (21) is z1, and the axial height of the protrusion (214) is z2, where 0.2*(yx)≤z1≤1.6*(yx).

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

7.

16. An electric 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 15, and the stator structure is sleeved on the outer periphery of the rotor structure.

17. The motor according to claim 16, characterized in that, The axial height of the rotor core (11) is x; the stator structure includes a stator core (31), the axial height of the stator core (31) is w, and x≥1.05*w.

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