Rotor core, motor and household appliance

Abstract

The utility model discloses a rotor core, a motor and a household electrical appliance, a first punching sheet comprises a central ring defining a shaft hole, first fan-shaped parts arranged at intervals in the circumferential direction of the central ring and a connecting part, the first fan-shaped parts are connected with the central ring through the connecting part, and one end, connected with the connecting part, of each first fan-shaped part is provided with a first inner magnetic bridge; a first outer magnetic bridge is arranged at one end, away from the central ring, of the first fan-shaped part; the second punching sheet comprises a plurality of second fan-shaped parts, the second fan-shaped parts are arranged around the circumferential direction of the shaft hole at intervals, a second inner magnetic bridge is arranged at one end, facing the shaft hole, of each second fan-shaped part, a second outer magnetic bridge is arranged at one end, away from the shaft hole, of each second fan-shaped part, and the first fan-shaped parts and the second fan-shaped parts are stacked to form a magnetic conductive block; the size of the first inner magnetic bridge is larger than that of the second inner magnetic bridge, and / or the size of the first outer magnetic bridge is larger than that of the second outer magnetic bridge. Therefore, the magnetic leakage can be improved, the motor efficiency can be improved, the assembling convenience of the rotor core can be considered, and the processing precision and the production efficiency can be improved.

Description

Technical Field

[0001] This application relates to the field of motor technology, and in particular to a rotor core, a motor, and a household appliance. Background Technology

[0002] Permanent magnet motors are characterized by high efficiency, high power density, and fast response.

[0003] The permanent magnet rotor is one of the core components of an electric motor, and its performance directly affects the motor's efficiency, performance, and reliability. However, existing permanent magnet rotors generally suffer from problems such as large magnetic leakage and insufficient mechanical strength. Magnetic leakage not only reduces the effective magnetic field strength of the motor, thus affecting its overall efficiency, but also increases unnecessary energy loss during operation, seriously impacting the motor's performance and stability. Utility Model Content

[0004] This application aims to at least address one of the technical problems existing in the prior art. To this end, one objective of this application is to provide a rotor core that can improve magnetic leakage and is easy to assemble.

[0005] This application further proposes a motor using the aforementioned rotor core.

[0006] This application also proposes a household appliance that uses the aforementioned motor.

[0007] In a first aspect, this application proposes a rotor core having a shaft hole and a plurality of magnetically conductive blocks spaced apart around the shaft hole, wherein adjacent magnetically conductive blocks form a magnet slot, and the magnet slot is suitable for mounting a permanent magnet, comprising:

[0008] A first lamination group and a second lamination group are arranged in groups, each first lamination group having at least one first lamination and each second lamination group having at least one second lamination, and the first lamination group and the second lamination group are stacked sequentially along the axial direction; wherein

[0009] The first lamination includes a central ring defining the shaft hole, a first sector portion arranged circumferentially on the central ring, and a connecting portion. The first sector portion is connected to the central ring through the connecting portion, and a first inner magnetic bridge is provided at one end of the first sector portion connected to the connecting portion, and a first outer magnetic bridge is provided at one end of the first sector portion away from the central ring.

[0010] The second lamination includes a plurality of second sector portions, which are arranged circumferentially around the shaft hole. A second inner magnetic bridge is provided at one end of the second sector portion facing the shaft hole, and a second outer magnetic bridge is provided at the end of the second sector portion away from the shaft hole. The first sector portion and the second sector portion are stacked to form the magnetic block, and the size of the first inner magnetic bridge is larger than the size of the second inner magnetic bridge, and / or the size of the first outer magnetic bridge is larger than the size of the second outer magnetic bridge.

[0011] According to the embodiments of this application, the rotor core is formed by stacking a first lamination and a second lamination, wherein the second lamination has no central ring and no connecting structure, the size of the second inner magnetic bridge is smaller than the size of the first inner magnetic bridge, and / or the size of the second outer magnetic bridge is smaller than the size of the first outer magnetic bridge. This can extend the leakage magnetic path between the rotor core and different magnetic poles, increase the magnetic resistance of the leakage magnetic path, and allow more magnetic flux to pass through the air gap and act on the stator, thereby improving leakage magnetic flux and increasing motor efficiency. At the same time, it can also take into account the ease of assembly of the rotor core, reduce assembly difficulty, improve processing accuracy and production efficiency.

[0012] According to some embodiments of this application, the width of the magnet slot is w1, the circumferential extension length of the first outer magnetic bridge is w2, the extreme width of the magnetic guide block is w3, the width of the magnetic guide block adjacent to one end of the first outer magnetic bridge is w4, the circumferential extension length of the first inner magnetic bridge is w5, the radial dimension of the first inner magnetic bridge is h1, the height of the magnet slot is h2, the radial dimension of the central ring is h3, and the radial dimension of the first outer magnetic bridge is h4, satisfying the following:

[0013] According to some embodiments of this application, the minimum distance between the first inner magnetic bridge and the central ring is h5, and satisfies 6≤(100*h5) / h2≤8.

[0014] According to some embodiments of this application, the circumferential extension length of the second outer magnetic bridge is w6, and satisfies 0.1≤w6 / w2<1.

[0015] According to some embodiments of this application, the circumferential extension length of the second inner magnetic bridge is w7, and satisfies 0.1≤w7 / w5<1.

[0016] According to some embodiments of this application, w7 also satisfies: 0.05≤w7 / w1≤0.2.

[0017] According to some embodiments of this application, the radial dimension of the second inner magnetic bridge is h6, and satisfies 0.01≤h6 / h2≤0.05.

[0018] According to some embodiments of this application, the rotor core further includes: an inner rotor core, which is disposed in the shaft hole and is plastically coated with the first lamination and the second lamination.

[0019] According to some embodiments of this application, the maximum outer diameter of the rotor inner core is D1, the inner diameter of the central ring is D2, and the following condition is met: 0.5≤D1 / D2≤0.8.

[0020] According to some embodiments of this application, the equivalent circle diameter of the side of the first inner magnetic bridge facing the central ring is D3, and satisfies: 0.2≤D1 / D3≤0.8.

[0021] Secondly, this application proposes an electric motor, comprising: the rotor core described in the above embodiments.

[0022] Thirdly, this application proposes a household appliance, including the motor described in the above embodiments.

[0023] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0024] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0025] Figure 1 This is a schematic diagram of the first lamination according to the first embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the first lamination according to the second embodiment of this application;

[0027] Figure 3 This is a schematic diagram of the second lamination according to the third embodiment of this application;

[0028] Figure 4 This is a schematic diagram of the second lamination according to the fourth embodiment of this application;

[0029] Figure 5 This is a schematic diagram of the second lamination according to the fifth embodiment of this application;

[0030] Figure 6 This is a schematic diagram of the fit between the first lamination and the inner core of the rotor according to an embodiment of this application;

[0031] Figure 7 This is a schematic diagram of the cooperation between the second lamination and the inner core of the rotor according to an embodiment of this application;

[0032] Figure 8This is a top view of the device core according to an embodiment of this application;

[0033] Figure 9 This is a schematic diagram of a second lamination according to an embodiment of this application;

[0034] Figure 10 This is a schematic diagram of the engagement of the first lamination and the second lamination according to an embodiment of this application;

[0035] Figure 11 This is a graph showing the per-unit value of motor efficiency as a function of the K value;

[0036] Figure 12 This is a graph showing the per-unit value of back electromotive force as a function of the value of K;

[0037] Figure 13 This is a comparison diagram of current and torque between the traditional solution and the present application;

[0038] Figure 14 This is a comparison chart of the per-unit demagnetizing current values ​​of the traditional scheme and the present application;

[0039] Figure 15 This is a comparison chart of the per-unit value of the line back EMF of the traditional scheme and that of this application;

[0040] Figure 16 This is a comparison chart of the per-unit electromagnetic cost of the traditional solution and the present application.

[0041] Figure label:

[0042] Rotor core 100, shaft hole 101, magnet slot 102, magnetic guide block 103, permanent magnet 200.

[0043] First lamination 10, central ring 11, first sector 12, first inner magnetic bridge 121, first outer magnetic bridge 122, connecting part 13.

[0044] Second lamination 20, second sector 21, second inner magnetic bridge 211, second outer magnetic bridge 212

[0045] Rotor inner core 30, injection molded receiving groove 31,

[0046] Positioning hole a, rivet point b, injection hole c. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0048] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0049] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0050] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0051] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0052] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0053] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0054] In the description of this application, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or the first and second features being in contact through another feature between them.

[0055] In the description of this application, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicate that the first feature is at a higher horizontal level than the second feature.

[0056] In this application, "multiple" means two or more (including two).

[0057] The following is for reference. Figures 1-16 This application describes a rotor core 100, a motor, and a household appliance according to embodiments thereof.

[0058] like Figure 8 , Figure 9 and Figure 10 As shown, this application proposes a rotor core 100, which has a shaft hole 101 and a plurality of magnetic blocks 103 located around the shaft hole 101 and spaced apart. A magnet slot 102 is formed between adjacent magnetic blocks 103, and a permanent magnet 200 is suitable for installation in the magnet slot 102.

[0059] Specifically, the rotor core 100 includes: a first lamination group and a second lamination group arranged in groups, each first lamination group having at least one first lamination 10, each second lamination group having at least one second lamination 20, and the first lamination group and the second lamination group being stacked sequentially along the axial direction.

[0060] In other words, combining Figure 9 and Figure 10As shown, the rotor core 100 is formed by stacking two types of laminations (i.e., first lamination 10 and second lamination 20) along the axial direction. The first laminations 10 can be arranged in groups to form a first lamination group, and the corresponding second laminations 20 can be arranged in groups to form a second lamination group. The first lamination group and the second lamination group can be stacked alternately, such as: a total of five lamination groups are set, which are arranged along the axial direction in the order of first lamination group, second lamination group, first lamination group, second lamination group, and first lamination group. Alternatively, the first lamination group can be located on both sides of the thickness direction of the second lamination group. This application does not make specific limitations.

[0061] See Figure 1 and Figure 2 As shown, the first lamination 10 includes a central ring 11 defining a shaft hole 101, a first sector 12 spaced circumferentially around the central ring 11, and a connecting portion 13. The first sector 12 is connected to the central ring 11 through the connecting portion 13, and a first inner magnetic bridge 121 is provided at one end of the first sector 12 connected to the connecting portion 13, and a first outer magnetic bridge 122 is provided at one end of the first sector 12 away from the central ring 11.

[0062] For example, 3. Figure 4 and Figure 5 As shown, the second lamination 20 includes a plurality of second sector portions 21, which are arranged circumferentially around the shaft hole 101. A second inner magnetic bridge 211 is provided at one end of the second sector portion 21 facing the shaft hole 101, and a second outer magnetic bridge 212 is provided at the other end of the second sector portion 21 away from the shaft hole 101. The first sector portion 12 and the second sector portion 21 are stacked to form a magnetic block 103.

[0063] In other words, a connecting portion 13 is provided radially outward of the central ring 11 of the first lamination 10. One radial end of the connecting portion 13 is connected to the central ring 11, and the other radial end is connected to the first sector portion 12. A first inner magnetic bridge 121 is provided at the end of the first sector portion 12 connected to the connecting portion 13, and a first outer magnetic bridge 122 is provided at the end of the first sector portion 12 away from the connecting portion 13. The second lamination 20 has no central ring 11 structure. Multiple second sector portions 21 are axially spaced in the shaft hole 101. A second inner magnetic bridge 211 can be provided at the end of the second sector portion 21 adjacent to the shaft hole 101, and a second outer magnetic bridge 212 can be provided at the end of the second sector portion 21 away from the shaft hole 101. No connecting portion is required on the side of the second inner magnetic bridge 211 facing the shaft hole 101.

[0064] It should be noted that the second outer magnetic bridges 212 of adjacent first sector portions 12 can be connected or spaced apart. Multiple second sector portions 21 can all be provided with second inner magnetic bridges 211, and the circumferential extension lengths of multiple second inner magnetic bridges 211 can also be different. Of course, multiple second sector portions 21 can also be partially provided with second inner magnetic bridges 211 and partially not provided with second inner magnetic bridges 211.

[0065] The first inner magnetic bridge 121 and the first outer magnetic bridge 122 can cooperate to limit the permanent magnet 200 in the magnet slot 102, and the second inner magnetic bridge 211 and the second outer magnetic bridge 212 can also cooperate to limit the permanent magnet 200 in the magnet slot 102. In this application, the second inner magnetic bridge 211 of unequal length can be set, and the second lamination 20 can be constructed as a lamination structure without a central ring 11 and without a connecting part 13. Alternatively, the second inner magnetic bridge 211 of equal length can be set, which can reduce the number of central rings 11 that define the shaft hole 101 of the rotor core 100, eliminate the connecting part 13 on the second sector 21, and reduce the size of at least part of the second inner magnetic bridge 211, so as to achieve the technical purpose of improving magnetic leakage.

[0066] Understandingly, magnetic leakage refers to the phenomenon where the magnetic flux generated by the permanent magnet 200 does not follow the expected path through the air gap to reach the stator and participate in work, but instead forms a closed loop through other unexpected paths. These unexpected paths are not necessarily limited to the rotor interior, but may also include other metal parts around the magnet, the motor housing, etc. The specific situation will vary depending on the motor's structure and magnetic circuit design. Magnetic leakage leads to a decrease in the utilization rate of the motor's magnetic field, affecting the motor's performance and efficiency, and increasing motor losses and heat generation.

[0067] Specifically, in this application, magnetic leakage refers to the phenomenon that the magnetic flux generated by the permanent magnet 200 does not pass through the air gap to do work, but forms a closed path inside the rotor. That is, the magnetic leakage path is from the N pole of the permanent magnet 200 to an adjacent magnetic block 103, to the back of the rotor core 100, to another adjacent magnetic block 103, and back to the S pole of the permanent magnet 200. By reducing the number of central rings 11 and the length of the second inner magnetic bridge 211 (i.e., setting unequal length second inner magnetic bridges 211), and omitting the connection 13 between the second sector 21 and the central ring 11, the magnetic resistance can be increased by extending the closed path formed inside the rotor core 100, so as to make the cross-sectional area of ​​the air gap region larger, and so that more magnetic flux can pass through the air gap to effectively improve magnetic leakage.

[0068] Furthermore, combined Figure 9 and Figure 10 As shown in the embodiments of this application, the size of the first inner magnetic bridge 121 is larger than the size of the second inner magnetic bridge 211, and / or the size of the first outer magnetic bridge 122 is larger than the size of the second outer magnetic bridge 212.

[0069] When multiple second laminations 20 and multiple first laminations 10 are stacked together along the axial direction to form a rotor core 100, the second outer magnetic bridge 212 on the second lamination 20 and the first outer magnetic bridge 122 on the first lamination 10 can cooperate with each other during the stacking process to form a magnetic circuit channel with a specific magnetic resistance distribution. The second outer magnetic bridge 212 plays a certain role in hindering the magnetic lines of force at its radial outer end, while the first outer magnetic bridge 122 can more effectively constrain the magnetic lines of force at its radial outer end due to its longer arc length. The combined effect of the two makes the magnetic field more inclined to be transmitted along the main magnetic circuit in the middle of the rotor core 100, reducing the disordered diffusion of magnetic lines of force in the middle region and building a relatively stable magnetic circuit foundation.

[0070] In this configuration, at least one first lamination 10 or at least one group of first laminations 10 are axially stacked on at least one side of the rotor core 100 in the thickness direction. This configuration can further strengthen the magnetic circuit structure of the entire rotor core 100. During motor operation, the outermost layer is in direct contact with the external environment and is prone to magnetic field leakage. However, the first outer magnetic bridge 122, with its long arc length advantage, can effectively block the outward divergence of magnetic lines of force on both sides of the rotor core 100, prevent the external environment from interfering with the internal magnetic circuit, and ensure that the magnetic lines of force in the internal magnetic circuit are transmitted along the predetermined main magnetic circuit direction, thereby strengthening the integrity and stability of the entire rotor core 100 magnetic circuit.

[0071] Furthermore, in embodiments where multiple second laminations 20 and multiple first laminations 10 are alternately stacked, during the alternating stacking process, the first outer magnetic bridge 122 with a longer arc length on the first lamination 10 and the second outer magnetic bridge 212 on the second lamination 20 form a tighter fit in the axial direction. During each alternating stacking process, the outer magnetic bridges of adjacent laminations fit tightly at their radial outer ends. When the magnetic field generated by the permanent magnet 200 diffuses towards the radial outer end, the upper first outer magnetic bridge 122 firstly constrains the magnetic lines of force with its longer arc length, and then the lower second outer magnetic bridge 212 blocks the magnetic lines of force again at the same radial outer end position, limiting both the cross-sectional area and length of the leakage magnetic path, thereby enhancing the magnetic resistance of the leakage magnetic path. Compared with a single outer magnetic bridge configuration, this significantly improves the stability of the magnetic path and the concentration of the magnetic field at the radial outer end.

[0072] In other words, in some embodiments, the size of the first inner magnetic bridge 121 is larger than the size of the second inner magnetic bridge 211. In other embodiments, the size of the first outer magnetic bridge 122 is larger than the size of the second outer magnetic bridge 212. In a preferred embodiment, while the size of the first inner magnetic bridge 121 is larger than the size of the second inner magnetic bridge 211, the size of the first outer magnetic bridge 122 is also larger than the size of the second outer magnetic bridge 212. Compared with the prior art, using first laminations 10 and second laminations 20 of different specifications to stack the rotor core 100 can make the closed path length formed by the rotor core 100 longer, the magnetic resistance greater, and more magnetic flux can be transmitted to the stator through the air gap, thereby improving leakage flux, enhancing the antimagnetic capability of the rotor core 100, and improving the performance of the rotor core 100.

[0073] In addition, only some of the stampings are constructed as second stampings 20, rather than all of them. This is because the multiple second sector portions 21 of the second stampings 20 are fully segmented, making positioning and splicing difficult. After the first stampings 10 are stacked, the second stampings 20 are further stacked. The first stampings 10 can also be used as an assembly reference to reduce assembly difficulty and improve production efficiency.

[0074] It is understandable that the number of first laminations 10 is preferably less than the number of second laminations 20. Therefore, the number of first laminations 10 in the first lamination group can be less than the number of second laminations 20 in the second lamination group. The first laminations 10 on the overall rotor core 100 can be only two pieces, while the number of second laminations 20 is more, so as to improve the leakage flux reduction effect.

[0075] According to the embodiments of this application, the rotor core 100 is formed by stacking a first lamination 10 and a second lamination 20, wherein the second lamination 20 has no central ring 11 and no connecting part 13 structure, the size of the second inner magnetic bridge 211 is smaller than the size of the first inner magnetic bridge 121, and / or the size of the second outer magnetic bridge 212 is smaller than the size of the first outer magnetic bridge 122. This can extend the leakage magnetic path between the rotor core 100 and different magnetic poles, increase the magnetic resistance of the leakage magnetic path, and allow more magnetic flux to pass through the air gap and act on the stator, thereby improving leakage magnetic flux and increasing motor efficiency. At the same time, it can also take into account the ease of assembly of the rotor core 100, reduce assembly difficulty, improve processing accuracy and production efficiency.

[0076] It is understandable that the cross-section of the permanent magnet 200 parallel to the rotor lamination is rectangular.

[0077] The shape of the rectangular permanent magnet determines the regularity and stability of the magnetic field distribution. Due to the symmetry of the rectangle, the magnetic field generated by the permanent magnet 200 is relatively uniformly distributed around it. During motor operation, a stable and uniform magnetic field distribution helps maintain the stability of the magnetic circuit. When the rotor rotates, the magnetic field generated by the rectangular permanent magnet interacts with the stator windings, driving the rotor to rotate. The uniform magnetic field distribution makes the electromagnetic force on the rotor more balanced during rotation, avoiding the unbalanced force on the rotor caused by uneven magnetic field distribution.

[0078] like Figure 1 As shown, according to some embodiments of this application, the width of the magnet slot 102 is w1, the circumferential extension length of the first outer magnetic bridge 122 is w2, the extreme width of the magnetic guide block 103 is w3, the width of the magnetic guide block 103 adjacent to one end of the first outer magnetic bridge 122 is w4, the circumferential extension length of the first inner magnetic bridge 121 is w5, the radial dimension of the first inner magnetic bridge 121 is h1, the height of the magnet slot 102 is h2, the radial dimension of the central ring 11 is h3, and the radial dimension of the first outer magnetic bridge 122 is h4, satisfying the following:

[0079] In other words, The obtained value is the coefficient K, and the range of coefficient K is 3-7.

[0080] The above formula is a combination formula, which can be broken down into (the product of the ratio of w5 to w1, the ratio of w4 to w1, and the ratio of w2 to w3) plus (the product of the ratio of h1 to h2, the ratio of h3 to h2, and the ratio of h4 to h2). The result should be greater than or equal to 3 and less than or equal to 7.

[0081] The ratio of w5 to w1 represents the ratio of the circumferential extension length of the first inner magnetic bridge 121 to the width of the magnet slot 102. The ratio of w4 to w1 represents the ratio of the radial outer width of the magnetic block 103 to the width of the magnet slot. The ratio of w2 to w3 represents the ratio of the circumferential extension length of the first outer magnetic bridge 122 to the maximum width of the magnetic block 103 (i.e., the length from one end of the first outer magnetic bridge 122 to the other end). These ratios respectively constrain the circumferential extension length of the first inner magnetic bridge 121 and the radial outer width of the magnetic block 103. The width and circumferential extension length of the first outer magnetic bridge 122, corresponding to the ratio of h1 to h2, represent the ratio of the radial dimension of the first inner magnetic bridge 121 to the height of the magnet slot 102; the ratio of h3 to h2 represents the ratio of the radial dimension of the central ring 11 to the height of the magnetic guide slot; and the ratio of h4 to h2 represents the ratio of the radial dimension of the first outer magnetic bridge 122 to the height of the magnetic guide slot, respectively constraining the radial dimensions of the first inner magnetic bridge 121, the first outer magnetic bridge 122, and the central ring 11.

[0082] In the formula, the height and width of the magnet slot 102 remain constant in the denominator, while the extreme width of the magnetic block 103 in the denominator is positively correlated with the circumferential extension length of the first outer magnetic bridge 122. In the numerator, the circumferential extension length of the first outer magnetic bridge 122, the circumferential extension length of the first inner magnetic bridge 121, and the radial outer end width of the magnetic block 103 are mutually constrained to make the circumferential extension length of the first outer magnetic bridge 122, the circumferential extension length of the first inner magnetic bridge 121, and the radial outer end width of the magnetic block 103 more reasonable. The radial dimensions of the first inner magnetic bridge 121, the second inner magnetic bridge 211, and the central ring 11 are mutually constrained to make the radial dimensions of the first inner magnetic bridge 121, the first outer magnetic bridge 122, and the central ring 11 more reasonable.

[0083] Therefore, by constraining the radial dimension and axial extension length of the first outer magnetic bridge 122, the radial dimension and axial extension length of the first inner magnetic bridge 121, the radial dimension of the central ring 11, and the radial outer width of the magnetic block 103, the final coefficient is between 3 and 7. Under the same size conditions, compared with the prior art, the permanent magnet 200 provided in this application can be larger, resulting in less leakage flux and a larger magnetic flux provided by the permanent magnet 200. Due to the reduction in leakage flux and the improved utilization rate of the main magnetic flux, the torque output is higher under the same current, the magnetic force is more uniform, the core saturation is delayed, a larger current injection is allowed without demagnetization, the copper loss per unit torque is reduced, and the overload duration is extended. Within the K value constraint range, the rotor core 100 can not only improve efficiency, but also significantly enhance the overload capacity of the motor through magnetic circuit anti-saturation design and magnetic flux distribution optimization.

[0084] like Figure 1 and Figure 2 As shown, according to some embodiments of this application, the minimum distance between the first inner magnetic bridge 121 and the central ring 11 is h5, and satisfies 6≤(100*h5) / h2≤8.

[0085] Specifically, the distance between the side surface of the first inner magnetic bridge 121 facing the central ring 11 and the radial outer surface of the central ring 11 is h5, and the ratio between h5 and h2 satisfies that h5 is between 0.06 and 0.08 times h2.

[0086] It is understandable that the position of the central ring 11 remains fixed, and the larger the ratio of h5 to h2, the smaller the size of the magnet slot 102, the smaller the volume of the permanent magnet 200 that can be accommodated, and the smaller the corresponding main magnetic flux. Limiting the ratio between 6 and 8 can, on the one hand, avoid the distance between the first inner magnetic bridge 121 and the central ring 11 being too close, thereby reducing the processing difficulty and taking into account production and manufacturing costs. On the other hand, it can ensure that the volume of the permanent magnet 200 set in the magnet slot 102 can meet the requirements, so as to improve leakage flux while taking into account the main magnetic flux, thereby ensuring the working efficiency of the motor.

[0087] like Figure 3 , Figure 4 and Figure 5 As shown, according to some embodiments of this application, the second outer magnetic bridge 212 extends circumferentially for a length of w6, and satisfies 0.1≤w6 / w2<1.

[0088] In other words, the circumferential extension length of the second outer magnetic bridge 212 formed on the second sector 21 needs to be less than the circumferential extension length of the first outer magnetic bridge 122 on the first sector 12, and should be greater than or equal to 0.1 times the circumferential extension length of the first outer magnetic bridge 122.

[0089] In other words, the circumferential arc length of the first outer magnetic bridge 122 is greater than that of the second outer magnetic bridge 212. Due to the length difference between the two outer magnetic bridges, the length of the leakage magnetic path increases, leading to an increase in magnetic reluctance and further reducing leakage. The magnetic lines of force, with the first outer magnetic bridge 122 being longer and the second outer magnetic bridge 212 shorter, tend to propagate along the center of the magnet slot 102 to the guide magnet block 103, reducing diffusion to the edges of the magnet slot 102 and the radially inner and outer ends of the non-main magnetic path regions, thus lowering the possibility of leakage. Simultaneously, because the rotor core 100 has a first lamination 10 on its outermost layer in the thickness direction, and this first lamination 10 has a relatively long first outer magnetic bridge 122, the entire rotor core 100 forms a larger magnetic reluctance on its outermost layer compared to the second lamination. During motor operation, this outermost layer is in direct contact with the external environment, making it prone to magnetic field leakage. The first outer magnetic bridge 122 of the first lamination 10 has a relatively long arc length, which can effectively block the outward divergence of magnetic lines of force in the outermost layer of the rotor core 100, further enhancing the suppression of leakage flux. Moreover, the outer first magnetic bridge 122 can also play a certain guiding and protective role for the internal magnetic circuit, ensuring that the magnetic lines of force in the internal magnetic circuit are transmitted along the direction of the main magnetic circuit, reducing the interference of the external magnetic field leakage on the internal magnetic circuit, thereby ensuring the stability and effectiveness of the magnetic circuit.

[0090] At the same time, ensuring that the circumferential extension length of the second outer magnetic bridge 212 is not less than 0.1 times the circumferential extension length of the first outer magnetic bridge 122 also ensures the limiting effect of the second inner magnetic bridge 211.

[0091] Combination Figure 3 , Figure 4 as well as Figure 5 As shown, according to some embodiments of this application, the circumferential extension length of the second inner magnetic bridge 211 is w7, and satisfies 0.1≤w7 / w5<1.

[0092] In other words, the circumferential extension length of the second inner magnetic bridge 211 formed on the second sector 21 needs to be less than the circumferential extension length of the first inner magnetic bridge 121 on the first sector 12, and should be greater than or equal to 0.1 times the circumferential extension length of the first inner magnetic bridge 121.

[0093] It should be noted that the first inner magnetic bridge 121 provided on the first sector 12 greatly reduces magnetic leakage by directionally restricting the path of magnetic lines of force. This can be understood as follows: during motor operation, magnetic lines of force may freely diffuse in various directions at the radial inner end, resulting in a significant loss of magnetic field energy. The first inner magnetic bridge 121, located within the magnet slot 102, only allows a small number of magnetic lines of force to pass through the high magnetic resistance region. Most magnetic lines of force can only be transmitted along the main magnetic circuit formed by the magnet slot 102 and the magnetic guide block 103. When the magnetic field generated by the permanent magnet 200 diffuses radially inward, the first inner magnetic bridge 121 on the same side almost completely blocks the magnetic lines of force leaking from that direction, forcing the magnetic lines of force to change direction within the magnet slot 102 and replan their path.

[0094] It should be noted that a first inner magnetic bridge 121 is provided on both sides of the axial direction of the magnet slot 102. The arrangement of the first inner magnetic bridge 121 on both sides constrains the magnetic lines of force from two directions. When the magnetic lines of force diffuse towards the radial inner end, the first inner magnetic bridge 121 on one side first blocks it, forcing the magnetic lines of force to change direction. When the magnetic lines of force attempt to diffuse from the other side, they will be blocked by the first inner magnetic bridge 121 on the other side. During the operation of the motor, the magnetic field generated by the permanent magnet 200 diffuses towards the radial inner end of the first sector 12. The first inner magnetic bridge 121 on the left side will block the magnetic lines of force that diffuse to the left, and the magnetic lines of force will diffuse to the right. However, the first inner magnetic bridge 121 on the right side will also intercept them. In the end, the magnetic lines of force can only be transmitted along the main magnetic circuit composed of the magnet slot 102 and the magnetic guide block 103, which effectively blocks the path of magnetic lines of force leakage from the radial inner end and greatly reduces the amount of magnetic leakage.

[0095] Furthermore, due to the unequal lengths of the multiple first inner magnetic bridges 121 and second inner magnetic bridges 211, the leakage magnetic flux at the radial inner end is controlled through the differentiated setting of local magnetic reluctance. During motor operation, the magnetic field tends to diffuse at the radial inner end of the sector. If the magnetic circuit structure is unreasonable, magnetic lines of force can easily leak from this area. The first inner magnetic bridges 121 and 211 with unequal arc lengths can effectively adjust the diffused magnetic lines of force according to their magnetic reluctance differences. The longer arc length of the first inner magnetic bridge 121, with its strong magnetic reluctance, forms a strong barrier on its side, blocking the path of outward diffusion of magnetic lines of force on that side. Although the shorter arc length of the second inner magnetic bridge 211 has relatively weaker constraint ability, it can still limit the magnetic lines of force to a certain extent. In conjunction with the longer arc length of the first inner magnetic bridge 121, it guides the magnetic lines of force to converge towards the main magnetic circuit. The combined effect of the two greatly suppresses the diffusion of magnetic lines of force at the radial inner end of the sector, reducing the leakage magnetic flux phenomenon in this area and ensuring that more magnetic field energy is used for the effective work of the motor.

[0096] Of course, the arc lengths of the multiple first inner magnetic bridges 121 can be unequal, and the arc lengths of the multiple second inner magnetic bridges 211 can also be unequal, which can also achieve the above-mentioned synergistic effect. At the same time, the minimum size limitation of the second inner magnetic bridge 211 makes the size of the second inner magnetic bridge 211 more reasonable, making the cooperation effect between the second inner magnetic bridge 211 and the first inner magnetic bridge 121 better, and can also have a certain limiting effect on the radial inner end of the permanent magnet 200.

[0097] According to some embodiments of this application, w7 also satisfies: 0.05≤w7 / w1≤0.2.

[0098] Specifically, the maximum circumferential extension dimension of the second inner magnetic bridge 211 is 0.2 times the width of the magnet slot 102, and the minimum is 0.05 times the width of the magnet slot 102.

[0099] This makes the circumferential extension dimension of the second inner magnetic bridge 211 more reasonable, avoiding an excessively small circumferential extension dimension, so as to take into account the effect of the second inner magnetic bridge 211 on the permanent magnet 200 on the radial inner side of the permanent magnet 200, and avoid an excessively large circumferential extension dimension, so as to improve the leakage flux suppression effect and improve the motor efficiency.

[0100] like Figure 4 As shown, according to some embodiments of this application, the radial dimension of the second inner magnetic bridge 211 is h6, and satisfies 0.01≤h6 / h2≤0.05.

[0101] In other words, the radial dimension of the second inner magnetic bridge 211 is 0.01 to 0.05 times the height of the magnet slot 102.

[0102] In this way, on the one hand, the height dimension of the second inner magnetic bridge 211 can be avoided to be too small, so as to take into account the structural strength of the second lamination 20 and the limiting effect on the permanent magnet 200. On the other hand, the radial dimension of the second inner magnetic bridge 211 can be avoided to be too large, so that there is more space for arranging the permanent magnet 200. Arranging a larger permanent magnet 200 can increase the magnetic flux and thus improve the electromagnetic performance.

[0103] like Figure 6 and Figure 7 As shown, according to some embodiments of this application, the rotor core 100 further includes: an inner rotor core 30, which is disposed in the shaft hole 101 and is plastically coated with the first lamination 10 and the second lamination 20.

[0104] Specifically, the rotor inner core 30 is provided with mounting holes for connecting the rotating shaft, and a plurality of magnetic blocks 103 are disposed on the outer periphery of the rotor inner core 30, and the outer wall of the rotor inner core 30 is injection molded to the plurality of magnetic blocks 103.

[0105] The mounting holes provided in the rotor inner core 30 for connecting the rotating shaft are the basic structure for realizing the power transmission of the motor. The presence of the mounting holes provides a positioning connection point for the rotating shaft. The outer wall of the rotor inner core 30 and multiple magnetic blocks 103 are connected by injection molding. During the injection molding process, the plastic material can fill the tiny gaps between the outer wall of the rotor inner core 30 and the magnetic blocks 103, forming a tight bond. On the one hand, it fixes the magnetic blocks 103 to the outer periphery of the rotor inner core 30, enhancing the structural strength and rigidity of the entire rotor core 100. When the motor rotates at high speed, the rotor will be subjected to mechanical forces such as centrifugal force. The injection molding connection can effectively resist external forces and prevent the magnetic blocks 103 from shifting or loosening. In high-power motors, the rotor rotates at high speed and the centrifugal force is large. The injection molding connection can ensure that the magnetic blocks 103 and the rotor inner core 30 always maintain a stable relative position, avoiding vibration and noise caused by structural looseness and improving the smoothness of motor operation. On the other hand, the injection molding connection can also play a buffering role. When the motor starts, stops, or the load changes, the rotor will be subjected to impact and vibration. The elasticity of the injection molding layer can absorb some of the impact force, reduce the stress concentration between the magnetic block 103 and the rotor core 30, reduce the risk of component damage caused by mechanical stress, and extend the service life of the rotor core 100.

[0106] In some embodiments of this application, the magnetic block 103 is also provided with injection molding holes, and the outer wall of the rotor inner core 30 is injection molded and connected to multiple magnetic blocks 103 by injection molding into the injection molding holes.

[0107] According to some embodiments of the present application, the rotor core 100 has a plurality of injection-molded receiving grooves 31 extending in the thickness direction on the outer periphery of the inner rotor core 30.

[0108] Multiple injection molding receiving grooves 31 that extend through the thickness direction are formed on the outer periphery of the rotor inner iron core 30. During the injection molding process, molten plastic material can fill these receiving grooves. After cooling and solidification, a more robust connection structure is formed between the plastic and the rotor inner iron core 30 and the magnetic block 103.

[0109] From a mechanical connection perspective, the injection-molded receiving groove 31 increases the contact area between the plastic and the rotor inner core 30. The structure with the receiving groove allows the plastic to be embedded within it, greatly enhancing the bonding force between the two. This bonding force is not only manifested in the axial direction, but also effectively restricts the relative displacement between the magnetic block 103 and the rotor inner core 30 in the circumferential and radial directions. When the motor rotates at high speed, centrifugal force will generate an outward pulling force on the rotor core 100, while the plastic part in the injection-molded receiving groove 31 can tightly hold the magnetic block 103, preventing it from loosening due to centrifugal force, and ensuring the integrity and stability of the entire component structure.

[0110] Furthermore, the through-hole design of the injection molding receiving groove 31 allows for uniform distribution of the plastic in the thickness direction, avoiding localized stress concentration. During motor operation, the rotor is subjected to external forces such as vibration and impact. If the plastic is unevenly distributed, excessive stress can easily occur in certain areas, leading to damage to the connection part 13. The through-hole design of the injection molding receiving groove 31 ensures continuous support of the plastic in the thickness direction, allowing external forces to be transmitted more evenly, further improving the mechanical strength and fatigue resistance of the component, and extending the service life of the rotor core 100.

[0111] It should be noted that the first lamination 10 and the second lamination 20 can also be provided with structures such as positioning holes a, rivet points b, and injection holes c. Positioning holes 123 can improve positioning accuracy, while injection holes c can be used to fill injection molding material. The injection molding material and rivet points b can fit well, effectively preventing loosening between the stacked laminations (i.e., multiple first laminations 10 and second laminations 20 stacked), and improving the structural reliability and stability of the rotor core 100.

[0112] It should be noted that the injection-molded receiving groove 31 on the outer periphery of the rotor inner core 30 is constructed as a dovetail tooth structure that narrows or widens radially outward, or is circular, elliptical, polygonal, elongated, or irregular in shape.

[0113] like Figure 6 As shown, according to some embodiments of this application, the maximum outer diameter of the rotor inner core 30 is D1, the inner diameter of the central ring 11 is D2, and satisfies: 0.5≤D1 / D2≤0.8; the equivalent circle diameter of the side of the first inner magnetic bridge 121 facing the central ring 11 is D3, and satisfies: 0.2≤D1 / D3≤0.5.

[0114] In other words, the maximum outer diameter of the rotor inner core 30 should be 0.8 times the inner diameter of the central ring 11, or 0.5 times the equivalent circle diameter of the first inner magnetic bridge 121 facing the side of the central ring 11. If the two values ​​are different, the smaller value should be selected. The minimum radius of the rotor inner core 30 should be 0.5 times the inner diameter of the central ring 11, or 0.2 times the equivalent circle diameter of the first inner magnetic bridge 121 facing the side of the central ring 11. If the two values ​​are different, the larger value should be selected.

[0115] This allows for a more reasonable size of the rotor inner core 30, preventing it from being too large and causing an excessively small gap between the rotor inner core 30 and the inner ring. This reduces the leakage of magnetic flux through the rotor inner core 30, thus improving magnetic leakage. At the same time, it prevents the rotor inner core 30 from being too small, ensuring the reliability and stability of the connection between the rotor core 100 and the shaft, and guaranteeing the structural strength and reliability of the rotor core 100.

[0116] like Figure 1 As shown, in the first embodiment of this application, a first external magnetic bridge 122 is provided at the radial outer end of the first sector portion 12 of the first lamination 10. A first external magnetic bridge 122 extending toward each other is formed on both sides of the same magnet slot 102, and the two first external magnetic bridges 122 are spaced apart.

[0117] like Figure 2 As shown, in the second embodiment of this application, a first external magnetic bridge 122 is provided at the radial outer end of the first sector portion 12 of the first lamination 10, and a first external magnetic bridge 122 is provided at the outer end of each magnet slot 102 to block the radially open side of the magnet slot 102, and the first external magnetic bridge 122 is simultaneously connected to two first sector portions 12 on both sides of the circumference of the magnet slot 102.

[0118] like Figure 3 As shown, in the third embodiment of this application, the structures of the plurality of second laminations 20 are the same, and the structures of the second inner magnetic bridges 211 at the radial inner ends of the plurality of second sector portions 21 are the same.

[0119] like Figure 4 As shown, in the fourth embodiment of this application, the structures of the plurality of second laminations 20 are the same, and the structures of the second inner magnetic bridges 211 at the radial inner ends of the plurality of second sector portions 21 are the same, but the circumferential extension dimension of the second inner magnetic bridge 211 in the fourth embodiment is larger than that of the second inner magnetic bridge 211 in the third embodiment.

[0120] like Figure 5As shown in the fifth embodiment of this application, among the plurality of second laminations 20, the structures of two adjacent second laminations 20 are different, and the circumferential extension dimension of the second inner magnetic bridge 211 of one of them is larger than the circumferential extension dimension of the other second inner magnetic bridge 211.

[0121] It is understood that the rotor core 100 in this application embodiment can be composed of the first lamination 10 of the first embodiment and the second embodiment and the second lamination 20 of the third embodiment, the fourth embodiment and the fifth embodiment, or it can be composed of only one type of first lamination 10 and one type of second lamination 20. This application does not make any specific limitation.

[0122] like Figure 11 The graph shows the per-unit value of motor efficiency as a function of the value of K. When K is between 3 and 7, the motor efficiency can be stably maintained in the maximum value range, between 82% and 89%, which ensures the best motor efficiency.

[0123] like Figure 12 As shown, the per-unit value of back EMF varies with the value of K. When K is between 3 and 7, the per-unit value of back EMF can be stably maintained within the maximum value range, between 0.79 and 0.94, which can ensure optimal electromagnetic performance.

[0124] like Figure 13 The figure shows a comparison of current and torque between the traditional solution and the present application. It can be seen that as the current increases, the torque increase of the present application is greater than that of the traditional solution. Based on the size design of the first lamination and the second lamination, the motor saturation is small, and the same current can produce a larger torque.

[0125] like Figure 14 The figure shown is a comparison of the per-unit demagnetizing current of the conventional solution and the present application. It can be seen that the size of the magnet slot of the present application can be made larger than that of the conventional solution, the permanent magnet 200 has better anti-demagnetizing ability and larger demagnetizing current. The per-unit demagnetizing current of the present application is 60% higher than that of the conventional solution.

[0126] like Figure 15 As shown in the figure, the per-unit value of the line back EMF of the present application is compared with that of the conventional solution. It can be seen that the present application has made the size of the permanent magnet 200 larger and the overall demagnetization of the rotor core 100 smaller through size design, which ultimately makes the per-unit value of the line back EMF of the present application 32% higher than that of the conventional solution.

[0127] like Figure 16The figure shown is a comparison of the per-unit electromagnetic cost of the traditional solution and the present application. It can be seen that the rotor core 100 of the present application embodiment has a small leakage flux of the motor after structural design, and the permanent magnet 200 can be set to be larger, which can reduce the stacking thickness of the motor. Therefore, less electromagnetic material can be used to achieve the same performance, and the electromagnetic cost can be reduced by 25% compared with the traditional solution.

[0128] Furthermore, please refer to the table below, which compares the efficiency of the technical solution of this application with that of the traditional solution under the same torque and speed.

[0129] This application Traditional solution Rotational speed (rpm) 1000 1000 Torque (Nm) 1.1 1.1 efficiency(%) 82 81

[0130] As shown in the table, when the speed is 1000 rpm and the torque is 1.1 Nm, the efficiency of the motor in this application is 1 percentage point higher than that of the traditional solution.

[0131] The following is a brief description of the motor according to an embodiment of this application.

[0132] The motor according to the embodiments of this application includes: the rotor core 100 in the above embodiments.

[0133] Specifically, the motor includes a rotor and a stator. The rotor includes a rotor core and a shaft. The shaft is connected to the inner rotor core 30 of the rotor core 100. The inner rotor core 30 is further connected to the magnetic block 103.

[0134] The rotating shaft is connected to the inner rotor core 30 in the rotor core 100. During the disassembly of the rotor core 100, only the inner rotor core 30 and the rotating shaft can be removed, while the rest of the rotor core 100 components can be completely removed, realizing the modular utilization of the rotor core 100 components. At the same time, due to the adoption of the rotor core 100 with reduced leakage flux, the magnetic flux passes through the air gap to participate in effective work, reducing iron loss and copper loss. The reduction of leakage flux directly reduces the eddy current loss of the core and the eddy current loss of the permanent magnet 200, extends the life of the insulation material, and improves the working stability and reliability of the motor.

[0135] In other words, the motor according to the embodiments of this application includes the rotor core 100 of any of the above embodiments. Since the motor according to this embodiment is provided with the rotor core 100 described in any of the above embodiments, the magnetic flux distribution inside the motor according to this application is deeply optimized through the rotor core 100, effectively suppressing the magnetic leakage phenomenon between the permanent magnet 200 and the magnetic guide block 103. The magnetic resistance of the magnetic leakage path is significantly improved, allowing more magnetic flux to pass through the air gap and participate in electromagnetic energy conversion, thereby greatly improving energy utilization. This not only reduces the eddy current loss of the core and the permanent magnet 200, but also reduces the temperature rise during operation, enabling the motor to maintain stable output under long-term high-load conditions, extending the service life of the insulation material and the permanent magnet 200. By limiting the size of the rotor core 100 components, the occurrence of core magnetic saturation can also be delayed, enabling the motor to withstand higher instantaneous current input and output stronger torque under overload conditions, while reducing the risk of demagnetization of the permanent magnet 200 due to the reverse magnetic field. In addition, the uniformity of magnetic flux density distribution effectively weakens the spatial harmonics of the air gap magnetic field, which not only reduces electromagnetic vibration and noise, but also reduces torque pulsation and improves the smoothness of motor operation.

[0136] This application further proposes a household appliance that uses the aforementioned motor and has the same technical effects as the aforementioned motor, which will not be described in detail here.

[0137] The rotor core 100, rotor, and other components and operations of the motor according to the embodiments of this utility model are known to those skilled in the art and will not be described in detail here.

[0138] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0139] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A rotor core, the rotor core having a shaft hole and a plurality of magnetically conductive blocks spaced apart around the shaft hole, wherein adjacent magnetically conductive blocks form magnet slots, and permanent magnets are adapted to be installed in the magnet slots, characterized in that, include: A first lamination group and a second lamination group are arranged in groups, each first lamination group having at least one first lamination and each second lamination group having at least one second lamination, and the first lamination group and the second lamination group are stacked sequentially along the axial direction; wherein The first lamination includes a central ring defining the shaft hole, a first sector portion arranged circumferentially on the central ring, and a connecting portion. The first sector portion is connected to the central ring through the connecting portion, and a first inner magnetic bridge is provided at one end of the first sector portion connected to the connecting portion, and a first outer magnetic bridge is provided at one end of the first sector portion away from the central ring. The second lamination includes a plurality of second sector portions, which are arranged circumferentially around the shaft hole. A second inner magnetic bridge is provided at one end of the second sector portion facing the shaft hole, and a second outer magnetic bridge is provided at the end of the second sector portion away from the shaft hole. The first sector portion and the second sector portion are stacked to form the magnetic block, and the size of the first inner magnetic bridge is larger than the size of the second inner magnetic bridge, and / or the size of the first outer magnetic bridge is larger than the size of the second outer magnetic bridge.

2. The rotor core according to claim 1, characterized in that, The width of the magnet slot is w1, the circumferential extension length of the first outer magnetic bridge is w2, the extreme width of the magnetic guide block is w3, the width of the magnetic guide block adjacent to one end of the first outer magnetic bridge is w4, the circumferential extension length of the first inner magnetic bridge is w5, the radial dimension of the first inner magnetic bridge is h1, the height of the magnet slot is h2, the radial dimension of the central ring is h3, and the radial dimension of the first outer magnetic bridge is h4, satisfying the following:

3. The rotor core according to claim 2, characterized in that, The minimum distance between the first inner magnetic bridge and the central ring is h5, and satisfies 6≤(100*h5) / h2≤8.

4. The rotor core according to claim 2, characterized in that, The second outer magnetic bridge extends circumferentially for a length of w6, and satisfies 0.1 ≤ w6 / w2 < 1.

5. The rotor core according to claim 2, characterized in that, The circumferential extension length of the second inner magnetic bridge is w7, and satisfies 0.1≤w7 / w5<1.

6. The rotor core according to claim 5, characterized in that, The w7 also satisfies: 0.05≤w7 / w1≤0.

2.

7. The rotor core according to claim 2, characterized in that, The radial dimension of the second inner magnetic bridge is h6, and satisfies 0.01≤h6 / h2≤0.

05.

8. The rotor core according to claim 1, characterized in that, The rotor core further includes an inner rotor core, which is disposed within the shaft hole and is plastically coated with the first lamination and the second lamination.

9. The rotor core according to claim 8, characterized in that, The maximum outer diameter of the rotor inner core is D1, and the inner diameter of the central ring is D2, satisfying the condition: 0.5≤D1 / D2≤0.

8.

10. The rotor core according to claim 9, characterized in that, The equivalent circle diameter of the side of the first inner magnetic bridge facing the central ring is D3, and satisfies: 0.2≤D1 / D3≤0.

8.

11. An electric motor, characterized in that, include: The rotor core according to any one of claims 1-10.

12. A household appliance, characterized in that, include: The motor according to claim 11.

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