Permanent magnets, rotor components, motors and electrical equipment

Abstract

This invention provides a permanent magnet, a rotor assembly, a motor, and electrical equipment. The permanent magnet includes two end faces and a circumferential surface. The circumferential surface includes a first side face, an outer side face, a second side face, and an inner side face, connected end-to-end. The projections of the first side face, outer side face, second side face, and inner side face onto the end faces are respectively a first side line, an outer side line, a second side line, and an inner side line. The projections of the circumferential surface onto the end faces have an axisymmetric structure. Both the inner and outer side lines include two edge arc segments and a middle segment located between the two edge arc segments. The centers of the two edge arc segments of the inner side line and / or the centers of the two edge arc segments of the outer side line are located between the central axis and the outer side line. The permanent magnet of this application is easy to process, reduces corner leakage magnetic flux, makes the air gap sinusoidal, and reduces back EMF harmonics, cogging torque, and torque pulsation.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a permanent magnet, a rotor assembly comprising the permanent magnet, a motor comprising the rotor assembly, and an electrical device comprising the motor. Background Art

[0002] At present, axial flux permanent magnet motors are widely used in home appliances, vehicles, industry and other fields as a power source. The permanent magnets of existing permanent magnet motors are mostly fan-shaped or circular. Among them, fan-shaped permanent magnets have serious magnetic leakage at the four corners, causing serious local saturation of the motor rotor, resulting in large back EMF harmonics, cogging torque and torque pulsation of the motor. Summary of the invention

[0003] In order to solve at least one of the above technical problems, a first object of the present invention is to provide a permanent magnet.

[0004] A second object of the present invention is to provide a rotor assembly comprising the permanent magnet.

[0005] A third object of the present invention is to provide a motor comprising the above rotor assembly.

[0006] A fourth object of the present invention is to provide an electrical device comprising the above-mentioned motor.

[0007] In order to achieve the above-mentioned purpose, the technical solution of the first aspect of the present invention provides a permanent magnet for use in a motor, wherein the permanent magnet comprises: two end faces; and a lateral circumferential surface, wherein the lateral circumferential surface comprises a first side face, an outer side face, a second side face and an inner side face which are connected end to end in sequence, wherein the projections of the first side face, the outer side face, the second side face and the inner side face on the end face are respectively a first side line, an outer line, a second side line and an inner line, wherein the projection of the lateral circumferential surface on the end face is an axisymmetric structure, wherein a line connecting the midpoint of the inner line and the midpoint of the outer line forms an axis of symmetry of the axisymmetric structure, and the axis of symmetry is configured to intersect perpendicularly with the central axis of the rotor assembly of the motor; wherein both the inner line and the outer line comprise two edge arc segments and a middle segment located between the two edge arc segments, and the center of the two edge arc segments of the inner line and / or the center of the two edge arc segments of the outer line are located between the central axis and the outer line.

[0008] The permanent magnet provided by the technical solution of the first aspect of the present invention adopts an optimized arc shape for the inner and outer sides of the permanent magnet. On the one hand, it is beneficial to increase the end distance between two adjacent permanent magnets, thereby reducing the leakage magnetic field between the corners of the two, and improving the utilization rate of the permanent magnet on the basis of using less permanent magnets; on the other hand, the optimized arc surface design is beneficial to the sinusoidalization of the air gap magnetic field, which is beneficial to reducing the back electromotive force harmonics, cogging torque and torque pulsation.

[0009] Specifically, the inner side and outer side of the existing sector-shaped permanent magnet are concentrically arranged around the central axis of the rotor assembly. That is to say, the center of the projection of the inner side and outer side of the existing sector-shaped permanent magnet on the end face of the permanent magnet is consistent with the projection of the central axis of the rotor assembly on the end face of the permanent magnet. In this way, the outer side faces of two adjacent permanent magnets are located on the same cylindrical surface, and the inner side faces are also located on the same cylindrical surface. Therefore, the end distance of two adjacent permanent magnets is equal to the spacing between the first side and the second side of the two adjacent permanent magnets.

[0010] The present application optimizes the shape of the permanent magnet, and the two edge arc segments of the inner line are symmetrically arranged on both sides of the middle section of the inner line, and the two edge arc segments of the outer line are symmetrically arranged on both sides of the middle section of the outer line. When the center of the circle of the two edge arc segments of the inner line is located between the central axis of the rotor assembly and the outer line, the radius of the inner corner of the permanent magnet of the present application is reduced compared with the existing fan-shaped permanent magnet. In this way, the edge parts of the inner side surfaces of the two adjacent permanent magnets are not on the same cylindrical surface, and the bending degree of the edge parts equivalent to the inner side surface is deepened relative to the prior art, resulting in the inner corners shrinking to the middle part, which is conducive to increasing the distance between the inner ends of the adjacent permanent magnets, thereby reducing the leakage magnetic flux of the inner corners of the permanent magnet, improving the utilization rate of the magnetic steel, and making the air gap sinusoidal, reducing the back electromotive force harmonics, cogging torque and torque pulsation.

[0011] Similarly, when the center of the two edge arc segments of the outer line is located between the central axis and the outer line, the radius of the outer corner of the permanent magnet of the present application is reduced compared to the existing fan-shaped permanent magnet. In this way, the edge of the outer side surface of the two adjacent permanent magnets is not on a cylindrical surface, and the degree of curvature of the edge of the outer side surface is deepened relative to the prior art, resulting in the inner corner shrinking to the middle part, which is conducive to increasing the distance between the outer ends of the adjacent permanent magnets, thereby reducing the leakage of the outer corner of the permanent magnet, and making the air gap sinusoidal, reducing the back electromotive force harmonics, cogging torque and torque pulsation. At the same time, the permanent magnet of the present application is a symmetrical structure with a regular shape and is easy to process.

[0012] It is understandable that in the present application, the permanent magnet can be magnetic steel or a permanent magnet made of other permanent magnetic materials. The motor is an axial flux permanent magnet motor, or a disc motor.

[0013] Among them, the central axis of the air gap of the motor is colinear with the central axis of the rotor assembly, so the projection of the central axis of the rotor assembly on the end face of the permanent magnet can also be recorded as the center of the air gap of the motor. Therefore, in the prior art, the center of the projection of the inner side and outer side of the sector permanent magnet on the end face of the permanent magnet is consistent with the center of the air gap. In the present application, the center of the edge arc segment deviates from the center of the air gap and is inconsistent with the center of the air gap. The middle segment of the inner line and the outer line can be a straight line segment or an arc segment.

[0014] In addition, the permanent magnet in the above technical solution provided by the present invention may also have the following additional technical features:

[0015] In the above technical solution, the middle segment of the inner line is an arc segment.

[0016] The middle section of the inner line adopts an arc segment, so that the inner line is smoother and is convenient for processing and forming the permanent magnet.

[0017] In the above technical solution, the middle segment of the inner line coincides with the center of the two edge arc segments of the inner line.

[0018] In the above technical solution, the center of the inner line is located on the symmetry axis.

[0019] With this design, the inner line is actually an arc, and the center of the arc is located on the axis of symmetry, so the inner side surface is located on a cylindrical surface, which can be integrally formed, easy to process, and beneficial to improving the processing efficiency of the permanent magnet.

[0020] In the above technical solution, the inner line bends and protrudes in a direction away from the outer line; or the inner line bends and protrudes in a direction close to the outer line.

[0021] The inner line bends and protrudes in a direction away from the outer line, and then bends and protrudes in a direction close to the central axis of the rotor assembly. This helps to further increase the distance between the inner ends of two adjacent permanent magnets, thereby further reducing the missed measurement between the inner corners of adjacent permanent magnets, which helps to improve the utilization rate of the magnetic steel.

[0022] Alternatively, the inner line may be bent and convexed toward the direction close to the outer line as required, and the specific selection is made according to actual application conditions.

[0023] In any of the above technical solutions, the two edge arc segments of the outer line are respectively recorded as the first arc segment and the second arc segment, the middle segment of the outer line is an arc segment and is recorded as the middle arc segment, the first arc segment and the second arc segment are symmetrical about the symmetry axis, and the centers of the first arc segment and the second arc segment are consistent, and the center of the middle arc segment is located on the symmetry axis.

[0024] Such a design makes the permanent magnet more regular in shape and more symmetrical in structure, thereby further reducing the processing difficulty and facilitating further improving the processing efficiency of the permanent magnet.

[0025] In the above technical solution, the center of the first arc segment, the center of the second arc segment and the center of the inner line are consistent, and the center of the middle arc segment deviates from the center of the inner line; or the center of the first arc segment, the center of the middle arc segment and the center of the second arc segment are consistent, and the center of the outer line deviates from the center of the inner line; or the center of the middle arc segment is consistent with the center of the inner line, and the center of the middle arc segment deviates from the centers of the first arc segment and the second arc segment; or the center of the first arc segment, the center of the middle arc segment, the center of the second arc segment and the center of the inner line are consistent; or the centers of the first arc segment and the second arc segment, the center of the middle arc segment and the center of the inner line deviate from each other.

[0026] When the inner line is a whole arc, the center of the inner line (denoted as O2), the center of the first arc segment and the second arc segment of the outer line (denoted as O3), and the center of the middle arc segment (denoted as O1) have the following five positional relationships:

[0027] O2 is consistent with O3 and deviates from O1 and is inconsistent with O1. This design allows the arc surface corresponding to the first arc segment (recorded as the first side arc surface), the arc surface corresponding to the second arc segment (recorded as the second side arc surface) and the inner side surface (also called the inner arc surface) to be processed by the same process, which is beneficial to improving the processing efficiency of the permanent magnet.

[0028] O1 is consistent with O3 and deviates from O2 and is inconsistent with O2. Such a design enables the entire outer side surface (also called outer arc surface) to be processed by the same process, thereby facilitating the improvement of the processing efficiency of the permanent magnet.

[0029] O1 is consistent with O2 and deviates from O3 and is inconsistent with O3. This design allows the inner side surface (also called the inner arc surface) and the middle arc segment (also called the middle surface) to be processed by the same process, which is beneficial to improving the processing efficiency of the permanent magnet.

[0030] O1, O2, and O3 are consistent. This design allows the inner side surface (also called the inner arc surface) and the entire outer side surface (also called the outer arc surface) to be processed through the same process. Conventional pancake-shaped permanent magnets can be quickly formed by trimming the two side surfaces, which reduces the processing difficulty and is beneficial to improving the processing efficiency of the permanent magnets.

[0031] Alternatively, O1, O2, and O3 may not be consistent, and the specific shape of the permanent magnet can be reasonably designed according to the specific needs of the motor.

[0032] In any of the above technical solutions, there is a smooth transition between the first side line and the edge arc segment; there is a smooth transition between the second side line and the edge arc segment.

[0033] Such a design facilitates the processing and forming of the permanent magnet and is beneficial to improving the processing efficiency of the permanent magnet.

[0034] In any of the above technical solutions, the first side line and the second side line are both straight line segments, and the extension lines of the first side line and the second side line intersect to form an angle α, and the relationship between α and the pole pair number P of the rotor assembly satisfies: α=180° / P.

[0035] The number of pole pairs of the rotor is P, and the number of permanent magnets included in the rotor assembly is twice that of P. This design facilitates uniform arrangement of multiple permanent magnets along the circumference of the rotor assembly.

[0036] In the above technical solution, the intersection of the extension lines of the first side line and the second side line is located on the symmetry axis and between the central axis and the inner line.

[0037] Such a design is conducive to further increasing the end distance between two adjacent permanent magnets, thereby further improving the corner magnetic leakage and further improving the motor performance.

[0038] The technical solution of the second aspect of the present invention provides a rotor assembly, comprising: a rotor core; and a permanent magnet as described in any one of the technical solutions of the first aspect, connected to the end surface of the rotor core.

[0039] The rotor assembly provided by the technical solution of the second aspect of the present invention includes the rotor assembly described in any one of the technical solutions of the first aspect, and thus has all the beneficial effects of any of the above technical solutions, which will not be described in detail here.

[0040] In the above technical solution, the permanent magnet is connected to the rotor core via a plastic overmolding body, and the plastic overmolding body covers at least a portion of the rotor core and at least a portion of the permanent magnet, so that the rotor core and the permanent magnet form an integrated structure.

[0041] This solution uses the form of integrated plastic coating to form an integrated structure between the rotor core and the permanent magnet, thereby achieving a fixed connection between the rotor core and the permanent magnet. Compared with the existing bonding method, the plastic coating effectively enhances the connection strength between the rotor core and the permanent magnet, and the plastic coating also plays a fixing and limiting role on the permanent magnet, and increases the connection area between the permanent magnet and other structures, thereby avoiding the risk of the permanent magnet falling off in whole or in part due to the loose surface bonding method in the prior art, effectively preventing the permanent magnet from falling off, and thus improving the reliability of the operation of the axial flux permanent magnet motor (or disc motor).

[0042] In the above technical solution, the rotor assembly further includes: a rotor disk, which is made of non-magnetic material; wherein the permanent magnet is connected to one end surface of the rotor core, and the rotor disk is connected to the other end surface of the rotor core.

[0043] The setting of the rotor disk facilitates the fixed connection between the rotor disk and the motor shaft without the need for the rotor core to be fixedly connected to the shaft, which is conducive to reducing the difficulty of connecting the rotor assembly with the shaft and ensuring the operational reliability of the rotor assembly. At the same time, the non-magnetic rotor disk is conducive to ensuring the overall strength of the rotor assembly and the flatness of the contact between the rotor disk and the rotor core without causing additional losses.

[0044] The technical solution of the third aspect of the present invention provides a motor, comprising: a stator assembly; and a rotor assembly as described in any one of the technical solutions of the second aspect, wherein the rotor assembly cooperates with the stator assembly and is suitable for rotating relative to the stator assembly.

[0045] The motor provided by the technical solution of the third aspect of the present invention includes the rotor assembly described in any one of the technical solutions of the second aspect, and thus has all the beneficial effects of any of the above technical solutions, which will not be repeated here.

[0046] The technical solution of the fourth aspect of the present invention provides an electrical device, comprising: a device body; and a motor as described in the technical solution of the third aspect, wherein the motor is connected to the device body.

[0047] The electrical equipment provided by the technical solution of the fourth aspect of the present invention includes the motor described in the technical solution of the third aspect, and thus has all the beneficial effects of any of the above technical solutions, which will not be repeated here.

[0048] In the above technical solution, the electrical equipment may be, but is not limited to: compressors, fans, pumps, refrigerators, air conditioners and other household appliances, vehicles, multi-split units and other industrial equipment, etc.

[0049] Additional aspects and advantages of the present invention will become apparent from the following description or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0051] Figure 1 is a schematic structural diagram of a permanent magnet according to an embodiment of the present invention;

[0052] Figure 2 is a schematic structural diagram of a permanent magnet according to an embodiment of the present invention;

[0053] Figure 3 is a schematic structural diagram of a permanent magnet according to an embodiment of the present invention;

[0054] Figure 4 is a schematic structural diagram of a permanent magnet according to an embodiment of the present invention;

[0055] Figure 5 is a schematic structural diagram of a permanent magnet according to an embodiment of the present invention;

[0056] Figure 6 is a schematic diagram of the three-dimensional structure of a permanent magnet according to an embodiment of the present invention;

[0057] Figure 7 is a schematic diagram of the structure of a rotor assembly according to some embodiments of the present invention;

[0058] Figure 8 is a schematic structural diagram of a rotor core according to some embodiments of the present invention;

[0059] Fig. 9 is a schematic diagram of the structure of a rotor disk according to some embodiments of the present invention;

[0060] Fig.10 is a schematic diagram of the structure of the inclusion body according to some embodiments of the present invention;

[0061] Fig.11 is a schematic block diagram of a motor according to some embodiments of the present invention;

[0062] Fig.12 It is a schematic block diagram of an electrical device according to some embodiments of the present invention.

[0063] in, Figures 1 to 12 The corresponding relationship between the reference numerals and component names in the figure is:

[0064] 1 rotor assembly, 10 permanent magnets, 20 rotor core, 30 rotor disk, 40 plastic package;

[0065] 11 first side surface, 110 second side surface, 111 first side line, 112 second side line; 120 inner side surface, 121 inner line; 130 outer side surface, 131 first arc segment, 132 second arc segment, 133 middle arc segment; 141 first end surface, 142 second end surface;

[0066] 21 inner groove, 22 outer groove;

[0067] 31 through hole, 32 shaft hole;

[0068] 41 external protrusion, 42 connecting column, 43 plastic coated end surface;

[0069] 100 motor, 102 stator assembly;

[0070] 200 electrical equipment, 202 equipment body. DETAILED DESCRIPTION

[0071] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0072] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0073] Refer to the following Figures 1 to 12 The permanent magnet, rotor assembly, motor and electrical equipment according to some embodiments of the present invention are described.

[0074] The permanent magnet 10 provided by the technical solution of the first aspect of the present invention is used in a motor. The permanent magnet comprises: two end surfaces and a side circumferential surface, such as Figure 6 shown.

[0075] Specifically, the side surface includes a first side surface 11, an outer side surface 130, a second side surface 110 and an inner side surface 120 which are connected end to end. Figure 6 The projections of the first side surface 11, the outer side surface 130, the second side surface 110 and the inner side surface 120 on the end surface are respectively the first side line 111, the outer side line, the second side line 112 and the inner side line 121. Figures 1 to 5 The projection of the side surface on the end surface is an axisymmetric structure, and the line connecting the midpoint of the inner line 121 and the midpoint of the outer line forms a symmetry axis of the axisymmetric structure, and the symmetry axis is configured to be suitable for perpendicularly intersecting with the central axis of the rotor assembly 1 of the motor. Both the inner line 121 and the outer line include two edge arc segments and a middle segment located between the two edge arc segments.

[0076] The centers of the two edge arc segments of the inner line 121 are located between the central axis and the outer line.

[0077] Alternatively, the centers of the two edge arc segments of the outer line are located between the central axis and the outer line.

[0078] Alternatively, the centers of the two edge arc segments of the inner line 121 and the centers of the two edge arc segments of the outer line are located between the central axis and the outer line.

[0079] The permanent magnet provided by the technical solution of the first aspect of the present invention adopts an optimized arc surface shape for the inner side surface 120 and the outer side surface 130 of the permanent magnet 10. On the one hand, it is beneficial to increase the end distance between two adjacent permanent magnets 10, thereby reducing the leakage magnetic field between the two corners, and improving the utilization rate of the permanent magnet 10 on the basis of using less permanent magnets 10; on the other hand, the optimized arc surface design is beneficial to the sinusoidalization of the air gap magnetic field, which is beneficial to reducing back electromotive force harmonics, cogging torque and torque pulsation.

[0080] Specifically, the inner side surface 120 and the outer side surface 130 of the existing sector-shaped permanent magnet 10 are both concentrically arranged around the central axis of the rotor assembly 1. That is to say, the center of the projection of the inner side surface 120 and the outer side surface 130 of the existing sector-shaped permanent magnet 10 on the end surface of the permanent magnet 10 is consistent with the projection of the central axis of the rotor assembly 1 on the end surface of the permanent magnet 10. In this way, the outer side surfaces 130 of two adjacent permanent magnets 10 are located on the same cylindrical surface, and the inner side surfaces 120 are also located on the same cylindrical surface. Therefore, the end distance of two adjacent permanent magnets 10 is equal to the distance between the first side surface 11 and the second side surface 110 of the two adjacent permanent magnets 10.

[0081] The present application optimizes the shape of the permanent magnet 10, and the two edge arc segments of the inner line 121 are symmetrically arranged on both sides of the middle section of the inner line 121, and the two edge arc segments of the outer line are symmetrically arranged on both sides of the middle section of the outer line. When the center of the two edge arc segments of the inner line 121 is located between the central axis of the rotor assembly 1 and the outer line, the radius of the inner corner of the permanent magnet 10 of the present application is reduced compared with the existing fan-shaped permanent magnet 10. In this way, the edge of the inner side surface 120 of the two adjacent permanent magnets 10 is not on a cylindrical surface, and the degree of curvature of the edge of the inner side surface 120 is deepened relative to the prior art, resulting in the inner corner shrinking to the middle part, which is conducive to increasing the distance between the inner ends of the adjacent permanent magnets 10, thereby reducing the leakage magnetic flux of the inner corner of the permanent magnet 10, improving the utilization rate of the magnetic steel, and making the air gap sinusoidal, reducing the back electromotive force harmonics, cogging torque and torque pulsation.

[0082] Similarly, when the center of the circle of the two edge arc segments of the outer line is located between the central axis and the outer line, compared with the existing fan-shaped permanent magnet 10, the radius of the outer corner of the permanent magnet 10 of the present application is reduced. In this way, the edge of the outer side surface 130 of the two adjacent permanent magnets 10 is not on a cylindrical surface, and the degree of curvature of the edge of the outer side surface 130 is deepened relative to the prior art, causing the inner corner to shrink to the middle part, which is conducive to increasing the distance between the outer ends of the adjacent permanent magnets 10, thereby reducing the leakage magnetic field of the outer corner of the permanent magnet 10, and making the air gap sinusoidal, reducing back electromotive force harmonics, cogging torque and torque pulsation. At the same time, the permanent magnet 10 of the present application is a symmetrical structure with a regular shape and is easy to process.

[0083] Among them, the central axis of the air gap of the motor is colinear with the central axis of the rotor assembly 1, so the projection of the central axis of the rotor assembly 1 on the end face of the permanent magnet 10 can also be recorded as the center of the air gap of the motor. Therefore, in the prior art, the center of the projection of the inner side surface 120 and the outer side surface 130 of the sector-shaped permanent magnet 10 on the end face of the permanent magnet 10 is consistent with the center of the air gap. In the present application, the center of the edge arc segment deviates from the center of the air gap and is inconsistent with the center of the air gap. The middle segment between the inner line 121 and the outer line can be a straight line segment or an arc segment.

[0084] It is understandable that in the present application, the permanent magnet 10 can be magnetic steel or a permanent magnet 10 made of other permanent magnetic materials. The motor is an axial flux permanent magnet motor, or a disc motor.

[0085] Furthermore, the middle section of the inner line 121 is an arc segment.

[0086] The middle section of the inner line 121 is an arc segment, so that the inner line 121 is relatively smooth, which is convenient for processing and forming the permanent magnet 10 .

[0087] Furthermore, the middle section of the inner line 121 is consistent with the center of the two edge arc segments of the inner line 121, such as Figures 1 to 5 shown.

[0088] The center of the inner line 121 is located on the symmetry axis. Figures 1 to 5 shown.

[0089] With this design, the inner line 121 is actually an arc, and the center of the arc is located on the axis of symmetry, so the inner side surface 120 is located on a cylindrical surface, which can be integrally formed, easy to process, and beneficial to improving the processing efficiency of the permanent magnet 10.

[0090] Furthermore, the inner line 121 is bent and convexly extended in a direction away from the outer line, such as Figures 1 to 5 shown.

[0091] The inner line 121 bends and protrudes in a direction away from the outer line, and then bends and protrudes in a direction close to the central axis of the rotor assembly 1, which is beneficial to further increase the distance between the inner ends of two adjacent permanent magnets 10, thereby further reducing the missed measurement between the inner corners of adjacent permanent magnets 10, which is beneficial to improve the utilization rate of the magnetic steel.

[0092] Of course, the inner line 121 can also be bent and protruded toward the direction close to the outer line as needed, which is close to the shape of the existing sector-shaped permanent magnet 10. The specific selection is based on actual application conditions.

[0093] Furthermore, the two edge arc segments of the outer line are respectively recorded as the first arc segment 131 and the second arc segment 132, and the middle segment of the outer line is an arc segment and is recorded as the middle arc segment 133. The first arc segment 131 and the second arc segment 132 are symmetrical about the symmetry axis, such as Figures 1 to 5 As shown, the centers of the first arc segment 131 and the second arc segment 132 are consistent, and the center of the middle arc segment 133 is located on the symmetry axis.

[0094] Such a design makes the permanent magnet 10 more regular in shape and more symmetrical in structure, thereby further reducing the processing difficulty and facilitating further improving the processing efficiency of the permanent magnet 10 .

[0095] When the inner line 121 is a whole arc, the center of the air gap is marked as O, and the center of the inner line 121 (marked as O2), the center of the first arc segment 131 and the second arc segment 132 of the outer line (marked as O3), and the center of the middle arc segment 133 (marked as O1) have the following five positional relationships:

[0096] 1) The center of the first arc segment 131, the center of the second arc segment 132 and the center of the inner line 121 are consistent, and the center of the middle arc segment 133 deviates from the center of the inner line 121, such as Figure 1 shown.

[0097] In other words, O2 is consistent with O3 and deviates from O1 and is inconsistent with O1, e.g. Figure 1 This design allows the arc surface corresponding to the first arc segment 131 (referred to as the first side arc surface), the arc surface corresponding to the second arc segment 132 (referred to as the second side arc surface), and the inner side surface 120 (also referred to as the inner arc surface) to be processed by the same process, thereby facilitating the improvement of the processing efficiency of the permanent magnet 10.

[0098] 2) The center of the first arc segment 131, the center of the middle arc segment 133 and the center of the second arc segment 132 are consistent, such as Figure 5 As shown, the center of the outer line deviates from the center of the inner line 121.

[0099] In other words, O1 is consistent with O3, and deviates from O2 and is inconsistent with O2, e.g. Figure 5 Such a design enables the entire outer side surface 130 (also referred to as an outer arc surface) to be processed by the same process, thereby facilitating the improvement of the processing efficiency of the permanent magnet 10 .

[0100] 3) The center of the middle arc segment 133 is consistent with the center of the inner line 121, and the center of the middle arc segment 133 deviates from the center of the first arc segment 131 and the second arc segment 132, such as Figure 4 shown.

[0101] In other words, O1 is consistent with O2, and deviates from O3 and is inconsistent with O3, e.g. Figure 4 Such a design enables the inner side surface 120 (also referred to as the inner arc surface) and the middle arc segment 133 (also referred to as the middle surface) to be processed by the same process, thereby facilitating the improvement of the processing efficiency of the permanent magnet 10 .

[0102] 4) The center of the first arc segment 131, the center of the middle arc segment 133, the center of the second arc segment 132 and the center of the inner line 121 are consistent, such as Figure 3 shown.

[0103] In other words, O1, O2, and O3 are consistent, such as Figure 3 Such a design enables the inner side surface 120 (also called the inner arc surface) and the entire outer side surface 130 (also called the outer arc surface) to be processed by the same process, and the conventional pancake-shaped permanent magnet 10 can be quickly formed by trimming the two side surfaces, which reduces the processing difficulty and is conducive to improving the processing efficiency of the permanent magnet 10.

[0104] 5) The centers of the first arc segment 131 and the second arc segment 132, the center of the middle arc segment 133 and the center of the inner line 121 deviate from each other, as shown in FIG. Figure 2 shown.

[0105] In other words, O1, O2, and O3 are not consistent, e.g. Figure 2 As shown, the specific shape of the permanent magnet 10 can be reasonably designed according to the specific needs of the motor.

[0106] In any of the above embodiments, there is a smooth transition between the first side line 111 and the edge arc segment, and there is a smooth transition between the second side line 112 and the edge arc segment.

[0107] Such a design facilitates the processing and forming of the permanent magnet 10 , and is beneficial to improving the processing efficiency of the permanent magnet 10 .

[0108] In any of the above embodiments, the first side line 111 and the second side line 112 are both straight line segments, and the extension lines of the first side line 111 and the second side line 112 intersect to form an angle α. α and the number of pole pairs P of the rotor assembly 1 satisfy: α = 180° / P.

[0109] The number of pole pairs of the rotor is P, and the number of permanent magnets 10 included in the rotor assembly 1 is twice that of P. This design facilitates uniform arrangement of the plurality of permanent magnets 10 along the circumference of the rotor assembly 1 .

[0110] Furthermore, the intersection of the extension lines of the first side line 111 and the second side line 112 is located on the symmetry axis and between the central axis and the inner line 121. Figures 1 to 5 shown.

[0111] Such a design is conducive to further increasing the end distance between two adjacent permanent magnets 10, thereby further improving the corner magnetic leakage and further improving the motor performance.

[0112] like Figure 7 As shown, the rotor assembly 1 provided by the embodiment of the second aspect of the present invention comprises: a rotor core 20 and a permanent magnet 10. The permanent magnet 10 is connected to the end surface of the rotor core 20.

[0113] The rotor assembly 1 provided in the embodiment of the second aspect of the present invention comprises the permanent magnet 10 described in any one of the embodiments of the first aspect, and thus has all the beneficial effects of any of the above embodiments, which will not be described in detail herein.

[0114] Furthermore, the rotor assembly 1 further includes an overmolding body 40 , which covers at least a portion of the rotor core 20 and at least a portion of the permanent magnet 10 , so that the rotor core 20 and the permanent magnet 10 form an integrated structure.

[0115] This solution uses the form of integral plastic coating to form an integral structure between the rotor core 20 and the permanent magnet 10, thereby achieving a fixed connection between the rotor core 20 and the permanent magnet 10. Compared with the existing bonding method, the plastic coating effectively enhances the connection strength between the rotor core 20 and the permanent magnet 10, and the plastic coating 40 also plays a fixing and limiting role on the permanent magnet 10, and increases the connection area between the permanent magnet 10 and other structures, thereby avoiding the risk of the permanent magnet 10 falling off in whole or in part due to the loose surface bonding method in the prior art, effectively preventing the permanent magnet 10 from falling off, and thus improving the reliability of the operation of the axial flux permanent magnet motor (or disc motor).

[0116] In some embodiments, the rotor assembly 1 further includes: a rotor disk 30, such as Figure 7The rotor disk 30 is made of non-magnetic material, the permanent magnet 10 is connected to one end surface of the rotor core 20 , and the rotor disk 30 is connected to the other end surface of the rotor core 20 .

[0117] The provision of the rotor disk 30 facilitates the fixed connection between the rotor disk 30 and the rotating shaft of the motor without the need for the rotor core 20 to be fixedly connected to the rotating shaft, which is beneficial for reducing the difficulty of connecting the rotor assembly 1 with the rotating shaft and also beneficial for ensuring the operating reliability of the rotor assembly 1.

[0118] At the same time, compared with the existing pressure plate solution, the non-magnetic rotor disk 30 is beneficial to ensuring the overall strength of the rotor assembly 1 and the flatness of the contact between the rotor disk 30 and the rotor core 20 on the basis of reducing eddy current losses.

[0119] Of course, for some motors, the rotor disk can be eliminated, and the permanent magnets can be directly connected to the rotor core. The rotor core can be connected to the shaft by injection molding.

[0120] Furthermore, the overmolded body 40 also covers at least a portion of the rotor disk 30, such as Figure 7 As shown, the rotor core 20, the permanent magnet 10 and the rotor disk 30 form an integrated structure.

[0121] The rotor core 20, the permanent magnet 10 and the rotor disk 30 are designed in an integrated plastic package so that the rotor core 20, the permanent magnet 10 and the rotor disk 30 form an integrated structure, which effectively enhances the structural strength of the rotor assembly 1 and is beneficial to overcoming the centrifugal force during the rotation of the rotor disk 30, which is beneficial to further prevent the permanent magnet 10 from falling off and reduce the axial deformation of the rotor caused by the operation of the rotor axial magnetic field, thereby avoiding the influence of the air gap uniformity and the sinusoidality of the air gap magnetic flux density of the motor due to the axial deformation of the rotor assembly 1, which is beneficial to ensure the sinusoidality of the motor back electromotive force and reduce the cogging torque and torque pulsation of the motor.

[0122] Specifically, the number of permanent magnets 10 is multiple, such as Figure 7 A plurality of permanent magnets 10 are attached to the rotor core 20 , and the plurality of permanent magnets 10 are arranged in a circular array around the central axis of the rotor core 20 .

[0123] The surface-mounted permanent magnet 10 is used to realize the assembly between the permanent magnet 10 and the rotor core 20, which simplifies the process difficulty, is conducive to improving production efficiency, and further improves the connection strength between the permanent magnet 10 and the rotor core 20, and further improves the reliability of the motor. Multiple permanent magnets 10 are arranged in a circular array around the central axis of the rotor core 20, with a regular structure, and are conducive to the stable operation of the motor.

[0124] Furthermore, the end surface of the permanent magnet 10 away from the rotor core 20 protrudes from the plastic body 40, such as Figure 7 shown.

[0125] The end face of the permanent magnet 10 away from the rotor core 20 protrudes from the plastic body 40, which is beneficial to reducing the distance between the permanent magnet 10 and the stator, which is beneficial to realizing the design of a small air gap of the motor, thereby reducing the amount of permanent magnet 10 used, improving the utilization rate of the permanent magnet 10, and increasing the power density of the motor.

[0126] Specifically, the end face of the plastic-coated body 40 away from the rotor core 20 is recorded as the plastic-coated end face 43, and the two end faces of the permanent magnet 10 are recorded as the first end face 141 and the second end face 142, respectively. The first end face 141 protrudes from the plastic-coated end face 43, and the second end face 142 is connected to the end face of the rotor core 20. The distance between the first end face 141 and the plastic-coated end face 43 is H, as shown in FIG. Figure 7 As shown, the size of H can be adjusted as needed.

[0127] Of course, the permanent magnet 10 can also be completely covered by the overmolding body 40 .

[0128] In some embodiments, further, the rotor core 20 is formed by laminating silicon steel sheets along the axial direction of the rotor core 20, such as Figure 8 shown.

[0129] Compared with the conventional integral rotor core 20 , the rotor core 20 of this solution adopts a stacked silicon steel sheet design, which is beneficial to further reduce the eddy current loss in the rotor disk 30 , thereby improving the operating efficiency of the motor.

[0130] Of course, the rotor core 20 may also adopt an integral structure.

[0131] The rotor core 20 is an integrated structure formed by welding.

[0132] The rotor core 20 is formed into an integrated structure by welding, and the welding strength is high and the process is mature, so it is beneficial to improve the structural strength of the rotor core 20 and reduce the process difficulty.

[0133] In any of the above embodiments, further, the outer side surface 130 of the rotor core 20 is provided with an outer groove 22, such as Figure 8 The plastic package 40 has an outer protrusion 41 adapted to the outer groove 22, as shown in FIG. Fig.10 The outer protrusion 41 is embedded in the outer groove 22 .

[0134] Furthermore, the rotor core 20 is an annular structure, such as Figure 8 The inner side surface 120 of the rotor core 20 is provided with an inner groove 21, as shown in FIG. Figure 8 The plastic package 40 has an inner protrusion that matches the inner groove 21, as shown in FIG. Fig.10 The inner protrusion is embedded in the inner groove 21.

[0135] The outer groove 22 is provided on the outer side surface 130 of the rotor core 20. During the overmolding, the liquid plastic will flow into the outer groove 22 and solidify to form an outer protrusion 41, so that a part of the overmolded body 40 is embedded in the outer groove 22, which is conducive to increasing the contact area between the rotor core 20 and the overmolded body 40, thereby improving the connection strength between the rotor core 20 and the overmolded body 40. At the same time, the outer groove 22 can also be used as a welding position to facilitate the welding of the rotor core 20.

[0136] There are multiple outer grooves 22 , and the multiple outer grooves 22 are spaced apart and evenly distributed along the circumference of the rotor core 20 .

[0137] Similarly, an inner groove 21 is provided on the inner side surface 120 of the rotor core 20. During overmolding, liquid plastic will flow into the inner groove 21 and solidify to form an inner protrusion, so that a portion of the overmolded body 40 is embedded in the inner groove 21. This is also beneficial to increase the contact area between the rotor core 20 and the overmolded body 40, thereby improving the connection strength between the rotor core 20 and the overmolded body 40.

[0138] There are multiple inner grooves 21 , and the multiple inner grooves 21 are spaced apart and evenly distributed along the circumference of the rotor core 20 .

[0139] Furthermore, the rotor disk 30 is an annular structure, such as Fig. 9 The inner side 120 of the rotor disk 30 is provided with a through hole 31, as shown in FIG. Fig. 9 The through hole 31 corresponds to the inner groove 21 of the rotor core 20, and the plastic body 40 has a connecting column 42, as shown in FIG. Fig.10 The connecting column 42 is embedded in the through hole 31 and the inner groove 21 .

[0140] A through hole 31 is provided on the inner side surface 120 of the rotor disk 30, and the through hole 31 corresponds to the position of the inner groove 21 of the rotor core 20. During overmolding, liquid plastic will flow into the through hole 31 and the inner groove 21, and solidify to form a connecting column 42, so that the rotor disk 30 and the rotor core 20 are tightly connected together, which is beneficial to improving the connection strength between the rotor disk 30 and the rotor core 20.

[0141] It can be understood that the portion of the connecting column 42 located in the inner groove 21 is the aforementioned inner protrusion.

[0142] The rotor disk 30 has an axial hole 32 in the middle thereof for accommodating the shaft of the motor. Furthermore, the inner side surface 120 of the rotor core 20 is also provided with a positioning groove, such as Figure 8 The inner side 120 of the rotor disk 30 is also provided with a positioning hole, such as Fig. 9The positioning holes are connected to the positioning grooves to facilitate accurate alignment of the rotor core 20 and the rotor disk 30 during assembly.

[0143] In a specific embodiment, the number of the positioning grooves is two, the two positioning grooves are symmetrically arranged, and the size of the positioning grooves is smaller than the size of the inner grooves 21, and the positioning grooves are located in the middle of two adjacent inner grooves 21. Correspondingly, the number of the positioning holes is two, and the size of the positioning holes is smaller than the size of the through holes 31, and the positioning holes are located in the middle of two adjacent through holes 31.

[0144] like Fig.11 As shown, the motor provided by the embodiment of the third aspect of the present invention includes: a stator assembly 102 and a rotor assembly 1 as any one of the embodiments of the second aspect, and the rotor assembly 1 cooperates with the stator assembly 102 and is suitable for rotating relative to the stator assembly 102.

[0145] The motor 100 provided in the embodiment of the third aspect of the present invention includes the rotor assembly 1 of any one of the embodiments of the second aspect, and thus has all the beneficial effects of any of the above embodiments, which will not be described in detail herein.

[0146] like Fig.12 As shown, the electrical device 200 provided in the embodiment of the fourth aspect of the present invention comprises: a device body 202 and a motor 100 as in the embodiment of the third aspect, wherein the motor 100 is connected to the device body 202 .

[0147] Specifically, the motor 100 is an axial flux permanent magnet motor 100 , or a disc motor 100 .

[0148] The electrical device 200 provided in the embodiment of the fourth aspect of the present invention includes the motor 100 of the embodiment of the third aspect, and thus has all the beneficial effects of any of the above embodiments, which will not be described in detail here.

[0149] In the above embodiment, the electrical equipment 200 may be, but is not limited to: compressors, fans, pumps, refrigerators, air conditioners and other household appliances, vehicles, multi-split units and other industrial equipment, etc.

[0150] Some specific embodiments are introduced below and compared with the prior art.

[0151] Axial flux permanent magnet motors are widely used in home appliances, vehicles, industry and other fields. As a power source, existing permanent magnet motor magnets are mostly fan-shaped or circular. The processing difficulty of fan-shaped magnets is relatively large, and the four corners have serious magnetic leakage, which causes serious local saturation of the motor rotor, resulting in large back EMF harmonics, cogging torque and torque pulsation of the motor, and the utilization rate of the inner side of the magnet is not high. The processing of circular magnets is relatively simple, but the overall utilization rate is not high, resulting in a small back EMF of the motor, which reduces the output capacity of the motor.

[0152] To this end, the present invention provides some magnetic steels, a rotor assembly 1 of a disc-type motor including the magnetic steels, and a disc-type motor including the rotor assembly 1.

[0153] Specific Example 1

[0154] A magnetic steel comprises an upper surface, a lower surface, an inner arc surface, an outer arc surface, and two side surfaces.

[0155] Among them, in the projection of the upper surface or the lower surface of the magnetic steel, the inner arc surface is composed of a section of circular arc, and the center of the circular arc constituting the inner arc surface is inconsistent with the center of the air gap, and the outer arc surface is composed of a left side surface, a right side surface and a middle surface, the left side surface and the right side surface are symmetrical about the middle surface, and the centers of the two are the same, and the center of the middle surface is located on the central symmetry line of the magnetic steel.

[0156] Specifically, to facilitate understanding with the accompanying drawings, the two end surfaces of the magnetic steel are referred to as the upper surface and the lower surface; the inner side surface 120 of the magnetic steel is referred to as the inner arc surface, and the radius of the inner side surface 120 is consistent; the outer side surface 130 of the magnetic steel is referred to as the outer arc surface, and the surfaces corresponding to the first arc segment 131, the middle arc segment 133, and the second arc segment 132 of the outer arc surface are referred to as the left side surface, the middle side surface, and the right side surface, respectively; the first side surface 11 and the second side surface 110 of the magnetic steel are referred to as the two side surfaces.

[0157] The unique design of the magnetic steel according to the present invention is convenient for processing compared with conventional fan-shaped magnetic tiles, reduces corner magnetic leakage, makes the air gap sinusoidal, reduces back electromotive force harmonics, cogging torque and torque pulsation. In addition, the magnetic steel has a regular shape and a symmetrical structure, which is easy to process.

[0158] Furthermore, the center of the arc forming the inner arc surface in the magnetic steel is located on the central symmetry line of the magnetic steel. Therefore, the inner arc surface can be formed in one piece. When the center of the inner arc surface and the center of the air gap are located on both sides of the inner arc surface, the inner arc surface presents a shape that bulges toward the center of the air gap; when the center of the inner arc surface and the center of the air gap are located on the same side of the inner arc surface, the inner arc surface presents a shape that bulges away from the center of the air gap. It can be applied according to actual application conditions.

[0159] Among them, when the center of the inner arc surface is located outside the magnetic steel, the distance between the ends of two adjacent magnetic steels is increased, which reduces the leakage magnetic flux between the corners of the two, which is beneficial to improving the utilization rate of the magnetic steel.

[0160] Furthermore, the center of the left side and the right side of the magnetic steel is consistent with the center of the arc forming the inner arc surface, such as Figure 1 Therefore, the left side, right side and inner arc surface of the magnetic steel can be processed by the same process, which is beneficial to improve the processing efficiency of the magnetic steel.

[0161] Specific Example 2

[0162] The difference from the specific example 1 is that the centers of the left side, right side and middle side of the magnetic steel are consistent, such as Figure 5 At this time, the outer arc surface of the magnetic steel can be formed in one piece, which reduces the processing difficulty and the processing steps, and is conducive to improving the processing efficiency of the magnetic steel.

[0163] Specific Example 3

[0164] The difference from the specific example 1 is that the left side, right side and middle side of the magnetic steel are consistent with the center of the arc constituting the inner arc surface, such as Figure 3 At this time, the magnetic steel can be formed quickly by cutting the edges of the two sides of the conventional round disk-shaped magnetic steel, which reduces the processing difficulty and is conducive to improving the processing efficiency of the magnetic steel.

[0165] Specific Example 4

[0166] The difference from the specific example 1 is that the center of the middle surface of the magnetic steel is consistent with the center of the inner arc surface, such as Figure 4 Therefore, the middle surface and the inner arc surface of the magnetic steel can be processed by the same process, which is beneficial to improve the processing efficiency of the magnetic steel.

[0167] Specific Example 5

[0168] The difference from the specific example 1 is that the centers of the left side, right side and middle side of the magnetic steel are consistent, and the center of the middle side is inconsistent with the center of the inner arc side. Figure 2 shown.

[0169] The inner side surface 120 and the outer side surface 130 of the above magnetic steel both adopt the optimized shape of the arc surface. On the one hand, it is beneficial to increase the distance between the ends of two adjacent magnetic steels, reduce the leakage magnetic field between the edges and corners of the two, and improve the utilization rate of the magnetic steel on the basis of using less permanent magnets 10. On the other hand, the optimized arc surface design is beneficial to the sinusoidalization of the air gap magnetic field, reducing the back electromotive force harmonics, cogging torque and torque pulsation.

[0170] In some embodiments, the two side surfaces of the magnetic steel have a smooth transition with the left side surface, the right side surface, and the inner arc surface, which is beneficial to the processing of the magnetic steel.

[0171] In some embodiments, the angle between the two side surfaces of the magnetic steel is α, α=360 / (2×P), where P is the number of pole pairs.

[0172] Specific Example 6

[0173] A rotor assembly 1 includes: a magnetic steel of any specific example described above, a rotor core 20, a non-magnetic rotor disk 30, and a plastic package 40 that integrates the magnetic steel, the rotor core 20, and the rotor disk 30 arranged in sequence.

[0174] According to the disc motor of the present invention, the non-magnetic rotor disc 30 and the integrally coated structure enhance the strength of the rotor structure, which is conducive to overcoming the centrifugal force when the rotor rotates, preventing the permanent magnet 10 from falling off, and reducing the axial deformation of the rotor. The non-magnetic rotor disc 30 is conducive to ensuring the overall strength of the rotor and the flatness of the contact with the rotor core 20 without causing additional losses, and on the other hand, the rotor disc 30 is connected to the motor shaft to ensure the reliability of the operation of the rotor assembly 1.

[0175] Furthermore, the upper surface or the lower surface of the magnet is attached to the rotor core 20, and a plurality of magnets are arranged cocentrically with the rotor core 20. The design of the surface-attached permanent magnet 10 simplifies the process difficulty.

[0176] Furthermore, the overmolding component forms a whole with the magnets, the rotor core 20 and the rotor disk 30 arranged in sequence, and the upper surface or the lower surface of the magnets not attached to the rotor core 20 protrudes from the end surface of the overmolding component.

[0177] The magnetic steel and the rotor core 20 are additionally connected together in the form of plastic coating, which avoids the risk of the magnetic steel bonded on the surface not being firmly bonded and causing the whole piece or part to fall off, thereby improving the reliability of the motor operation. In addition, the design form of plastic coating all the rotor components enhances the overall strength of the rotor structure, which is conducive to overcoming the centrifugal force when the rotor disk 30 rotates, and reduces the axial deformation of the rotor caused by the operation of the rotor axial magnetic field, thereby affecting the air gap uniformity of the motor, affecting the sinusoidality of the air gap magnetic flux density of the motor, and is conducive to ensuring the sinusoidality of the back electromotive force and reducing the cogging torque and torque pulsation of the motor. The end face of the magnetic steel opposite to the air gap protrudes from the end face of the plastic coating body 40, which is conducive to ensuring the design of a small air gap of the motor, thereby reducing the amount of permanent magnets 10, improving the utilization rate of permanent magnets 10, and increasing the power density of the motor.

[0178] Furthermore, the rotor core 20 is formed by axially stacking silicon steel sheets, and an inner groove 21 is provided at the inner radius of the rotor core 20, and an outer groove 22 is provided at the outer radius. Compared with the conventional integral iron core rotor, the rotor core 20 is designed with silicon steel sheets, which is conducive to reducing the eddy current loss in the rotor disk 30 and improving the operating efficiency of the motor.

[0179] Furthermore, the rotor core 20 is welded into an integrated structure by using the outer groove 22 of the rotor core 20. At the same time, the outer groove 22 increases the contact surface of the overmolding structure, which is beneficial to enhance the connection strength between the injection molding component and other parts of the rotor.

[0180] Furthermore, a through hole 31 is provided on the inner side surface 120 of the rotor disk 30 , and the through hole 31 corresponds to the position of the groove 21 in the rotor core 20 , so as to facilitate the fixing of the rotor disk 30 and the rotor core 20 together during the overmolding.

[0181] In the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0182] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front” and “back” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0183] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0184] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A permanent magnet for a motor, characterized in that: The motor comprises an axial flux permanent magnet motor or a disc motor, and the permanent magnet comprises: two end faces; and A lateral surface, the lateral surface comprising a first side surface, an outer side surface, a second side surface and an inner side surface which are sequentially connected end to end, the projections of the first side surface, the outer side surface, the second side surface and the inner side surface on the end surface are respectively a first side line, an outer side line, a second side line and an inner side line, the projection of the lateral surface on the end surface is an axisymmetric structure, a line connecting the midpoint of the inner line and the midpoint of the outer line forms a symmetry axis of the axisymmetric structure, and the symmetry axis is configured to be suitable for perpendicularly intersecting with the central axis of the rotor assembly of the motor; Wherein, the inner line and the outer line both include two edge arc segments and a middle segment located between the two edge arc segments, the centers of the two edge arc segments of the inner line and / or the centers of the two edge arc segments of the outer line are located between the central axis and the outer line, the projection of the central axis of the rotor assembly on the end surface of the permanent magnet is the center of the air gap of the motor, and the center of the edge arc segment is inconsistent with the center of the air gap; The inner line bends and convexly extends in a direction away from the outer line; The first side line and the second side line are both straight line segments, and the extension lines of the first side line and the second side line intersect to form an angle α, and the angle between α and the number of pole pairs P of the rotor assembly satisfies: α=180° / P; The intersection of the extended lines of the first side line and the second side line is located on the symmetry axis and between the central axis and the inner line.

2. The permanent magnet according to claim 1, characterized in that The middle section of the inner line is an arc segment.

3. The permanent magnet according to claim 2, characterized in that The middle section of the inner line coincides with the center of the two edge arc segments of the inner line.

4. The permanent magnet according to claim 3, characterized in that The center of the inner line is located on the symmetry axis.

5. The permanent magnet according to any one of claims 1 to 4, characterized in that The two edge arc segments of the outer line are respectively recorded as the first arc segment and the second arc segment, the middle segment of the outer line is an arc segment and is recorded as the middle arc segment, the first arc segment and the second arc segment are symmetrical about the symmetry axis, and the centers of the first arc segment and the second arc segment are consistent, and the center of the middle arc segment is located on the symmetry axis.

6. The permanent magnet according to claim 5, characterized in that The center of the first arc segment, the center of the second arc segment and the center of the inner line are consistent, and the center of the middle arc segment deviates from the center of the inner line; or The center of the first arc segment, the center of the middle arc segment and the center of the second arc segment are consistent, and the center of the outer line deviates from the center of the inner line; or The center of the middle arc segment is consistent with the center of the inner line, and the center of the middle arc segment deviates from the centers of the first arc segment and the second arc segment; or The center of the first arc segment, the center of the middle arc segment, the center of the second arc segment and the center of the inner line are consistent; or The centers of the first arc segment and the second arc segment, the center of the middle arc segment, and the center of the inner line deviate from each other.

7. The permanent magnet according to any one of claims 1 to 4, characterized in that There is a smooth transition between the first side line and the edge arc segment; The second side line and the edge arc segment have a smooth transition.

8. A rotor assembly, characterized in that: include: Rotor core; and The permanent magnet according to any one of claims 1 to 7, connected to an end surface of the rotor core.

9. The rotor assembly according to claim 8, characterized in that The permanent magnet is connected to the rotor core via a plastic overmolding body, and the plastic overmolding body covers at least a portion of the rotor core and at least a portion of the permanent magnet, so that the rotor core and the permanent magnet form an integrated structure.

10. The rotor assembly according to claim 8 or 9, characterized in that: Also includes: A rotor disk, wherein the rotor disk is made of a non-magnetic material; The permanent magnet is connected to one end surface of the rotor core, and the rotor disk is connected to the other end surface of the rotor core.

11. A motor, characterized in that: include: stator assembly; and The rotor assembly according to any one of claims 8 to 10, wherein the rotor assembly cooperates with the stator assembly and is suitable for rotating relative to the stator assembly.

12. An electrical device, characterized in that: include: Equipment body; and The motor according to claim 11, wherein the motor is connected to the device body.

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