Permanent magnet motor
By designing an asymmetrical permanent magnet structure, the problem of cogging torque in permanent magnet motors was solved, achieving stable motor operation and noise reduction, and optimizing the magnetic circuit design.
Patent Information
- Application Number
- CN202422917372.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-28
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2034-11-28
AI Technical Summary
In existing permanent magnet motors, the interaction between the permanent magnet and the stator slots causes cogging torque, which affects the motor's speed fluctuations and vibrations, reducing working efficiency.
The upper and lower surfaces of the permanent magnet are designed to be adjacent to each other with opposite polarities along the circumference of the rotor core and are connected by a first end and a second end. The radial thickness of the first end is smaller than that of the second end, forming an asymmetrical structure, which reduces the uneven air gap between the stator assembly and the rotor assembly and optimizes the magnetic circuit.
It effectively reduces cogging torque, improves motor operating stability, reduces operating noise, optimizes the magnetic circuit, and ensures smooth motor operation.
Smart Images
Figure CN223729528U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of electric machines, and in particular to a permanent magnet electric machine. BACKGROUND
[0002] In the prior art, there is a slot torque between the permanent magnet and the core tooth slot of the stator in the permanent magnet electric machine, which will cause the speed fluctuation, vibration and other additional problems of the electric machine, and affect the working efficiency of the electric machine. CONTENT OF THE INVENTION
[0003] The present application aims to at least solve one of the above problems, and provides a permanent magnet electric machine to reduce the slot torque generated by the interaction between the stator tooth slot and the permanent magnet of the electric machine.
[0004] The present application provides a permanent magnet electric machine, comprising a rotor assembly, comprising:
[0005] The rotor assembly comprises a rotor core and a plurality of permanent magnets, the permanent magnets are arranged in pairs on the outer surface of the rotor core in sequence, and any permanent magnet is provided with an upper surface and a lower surface; wherein the polarities of the upper surfaces of the circumferentially adjacent permanent magnets along the outer surface of the rotor core are opposite, and the polarities of the lower surfaces of the circumferentially adjacent two permanent magnets along the outer surface of the rotor core are opposite.
[0006] The upper surface of the permanent magnet is arranged away from the axis of the rotor core relative to the lower surface of the permanent magnet; the upper surface of the permanent magnet is connected to the lower surface of the permanent magnet through a first end and a second end respectively; the first thickness of the first end along the radial direction of the rotor core is less than the second thickness of the second end along the radial direction of the rotor core.
[0007] Preferably, the thickness of the permanent magnet gradually increases from the first thickness to the second thickness in the direction from the first end to the second end along the circumferential direction of the rotor core, or gradually increases from the first thickness to the maximum thickness and then decreases to the second thickness.
[0008] Preferably, the first end is provided with a first upper edge and a first lower edge, and the axis of the rotor core is arranged on a plane extending from the first upper edge to the first lower edge, so that the first upper edge, the first lower edge and the axis of the rotor core are coplanar; wherein the first upper edge and the first lower edge are parallel to each other, and the distance between the first upper edge and the first lower edge constitutes the first thickness.
[0009] Preferably, the second end is provided with a second upper edge and a second lower edge, and the axis of the rotor core is arranged on a plane extending from the second upper edge to the second lower edge, so that the second upper edge, the second lower edge and the axis of the rotor core are coplanar; wherein the second upper edge and the second lower edge are parallel to each other, and the distance between the second upper edge and the second lower edge constitutes the second thickness.
[0010] Preferably, the lower surface of the permanent magnet is arranged as a right circular cylindrical surface, and the axis of the lower surface of the permanent magnet is coaxially arranged with the axis of the rotor core.
[0011] Preferably, the upper surface of the permanent magnet is arranged as a right circular cylinder, wherein the axis of the upper surface of the permanent magnet is arranged parallel to the axis of the rotor core; and the axis of the upper surface of the permanent magnet is not coincident with the axis of the rotor core.
[0012] Preferably, the first thickness is greater than or equal to half of the second thickness.
[0013] Preferably, the first thickness is greater than or equal to 2mm and less than 4.5mm.
[0014] Preferably, the maximum thickness of the permanent magnet in the radial direction of the rotor core is greater than or equal to the second thickness.
[0015] Preferably, the permanent magnet motor further comprises a stator assembly coaxially sleeved outside the rotor assembly; wherein
[0016] The stator assembly comprises a stator core and a winding, the stator core is provided with a ring yoke portion, the ring yoke portion extends in the direction of the axis of the rotor core and is provided with a plurality of teeth, the teeth are provided with an arc surface in the direction close to the rotor assembly, and the arc surface is coaxially arranged with the rotor core; a gap is arranged between adjacent teeth, and the winding is wound on the teeth through the gap; there is an air gap between any permanent magnet and any tooth.
[0017] Preferably, the ratio of the minimum value of the air gap to the radius of the arc surface of the tooth is 0.002 to 0.0053.
[0018] Preferably, the rotor assembly further comprises a rotating shaft, the rotating shaft is arranged through the rotor core, and the rotating shaft is coaxially arranged with the rotor core and the stator core; the rotating shaft is fixedly arranged relative to the rotor core.
[0019] Preferably, the permanent magnet motor further comprises a bearing and a housing; the housing is internally provided with a containing cavity, the bearing is contained in the containing cavity, the bearing is sleeved on a rolling shaft, and the bearing is coaxially arranged with the rolling shaft; the housing is also used to contain the rotor assembly and the stator assembly, and the rolling shaft is arranged through the housing.
[0020] Preferably, the permanent magnet motor further comprises a fixing member, the housing comprises a first housing and a second housing, wherein
[0021] The first housing and the second housing are arranged on the outside of the coaxially arranged rotor core and stator core from both sides along the axial direction of the rotating shaft; the fixing member is used to combine the first housing and the second housing to form the containing cavity.
[0022] The thickness of the first end in the radial direction of the rotor core is less than the thickness of the second end in the radial direction of the rotor core, so that the permanent magnet forms an asymmetric structure, thereby forming an uneven air gap between the stator assembly and the rotor assembly, reducing the cogging torque, optimizing the magnetic circuit of the motor, and at the same time making the motor run smoothly and reducing the operating noise
[0023] Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and the attendant drawings or can be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS
[0024] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.
[0025] Figure 1 It is a combination state schematic diagram of the rotor assembly disclosed by the present application;
[0026] Figure 2 It is a specific structure schematic diagram of any permanent magnet disclosed by the present application;
[0027] Figure 3 It is still another specific structure schematic diagram and partial enlarged view of any permanent magnet disclosed by the present application;
[0028] Figure 4 It is a combination state schematic diagram of the rotor core and permanent magnet disclosed by the present application;
[0029] Figure 5 It is a radial sectional view of the rotor core and permanent magnet disclosed by the present application;
[0030] Figure 6 It is a radial sectional view and partial enlarged view of the combination state of the stator assembly and rotor assembly disclosed by the present application;
[0031] Figure 7 It is a structure schematic diagram of the permanent magnet motor disclosed by the present application;
[0032] Figure 8 It is a combination state schematic diagram of the permanent magnet motor disclosed by the present application;
[0033] Figure 9 It is a sectional view of the combination state of the permanent magnet motor disclosed by the present application. DETAILED DESCRIPTION
[0034] The embodiments of the present application are described in detail below, examples of the embodiments are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.
[0035] In the description of the present application, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.
[0036] The application provides a permanent magnet motor, comprising a rotor assembly, comprising:
[0037] The rotor assembly comprises a rotor core 12 and a plurality of permanent magnets 11, the permanent magnets 11 are arranged in pairs on the outer surface of the rotor core 12 in sequence, and any permanent magnet 11 is provided with an upper surface S1 and a lower surface S2; wherein the upper surfaces S1 of the circumferentially adjacent permanent magnets 11 of the rotor core 12 are opposite in polarity, and the lower surfaces S2 of the circumferentially adjacent two permanent magnets of the rotor core 12 are opposite in polarity.
[0038] The upper surface S1 of the permanent magnet 11 is arranged away from the axis 121 of the rotor core 12 relative to the lower surface S2 of the permanent magnet 11; the upper surface S1 of the permanent magnet 11 is connected to the lower surface S2 of the permanent magnet 11 through the first end 111 and the second end 112 respectively; the first thickness D1 of the first end 111 in the radial direction of the rotor core 12 is less than the second thickness D2 of the second end 112 in the radial direction of the rotor core 12.
[0039] As shown in Figure 1 , the permanent magnet motor further comprises a stator assembly, the stator assembly comprises a stator core 21 and a plurality of coils 22, the coils 22 are arranged in pairs on the outer surface of the stator core 21 in sequence, and any coil 22 is provided with an upper surface S3 and a lower surface S4; wherein the upper surfaces S3 of the circumferentially adjacent coils 22 of the stator core 21 are opposite in polarity, and the lower surfaces S4 of the circumferentially adjacent two coils of the stator core 21 are opposite in polarity. Figure 1This diagram illustrates the combined state of permanent magnets 11a and 11b with the rotor core 12. Multiple permanent magnets are used, such as 11a, 11b, and other unlabeled permanent magnets. These permanent magnets 11 are sequentially arranged on the outer surface of the rotor core 12, at equal intervals along the outer circumference of the rotor core 12. The polarities of any two adjacent permanent magnets 11 are opposite. Specifically, taking permanent magnets 11a and 11b as examples, and assuming the upper surface S1 of permanent magnet 11a is the N pole, the upper surface S1 of permanent magnet 11b is set as the S pole, the lower surface S2 of permanent magnet 11a is the S pole, and the lower surface S2 of permanent magnet 11b is set as the N pole. Alternatively, the upper surface S1 of permanent magnet 11a can also be set as the S pole; no special restriction is imposed. Figure 1 Taking any permanent magnet 11 as an example, refer to Figure 2 The upper surface S1 and lower surface S2 of the permanent magnet 11 are set as arc surfaces. The upper surface S1 and lower surface S2 are connected by the first end 111 and the second end 112, respectively. The thickness of the first end 111 along the radial direction of the rotor core 12 is less than the thickness of the second end 112 along the radial direction of the rotor core 12, which causes the permanent magnet 11 to form an asymmetrical structure, thereby forming an uneven air gap d between the stator assembly 20 and the rotor assembly. This reduces the cogging torque, optimizes the motor magnetic circuit, and makes the motor run smoothly while reducing operating noise.
[0040] Specifically, the upper surface S1 and lower surface S2 of the permanent magnet 11 can have different shapes. The distance from any point on the rotor core axis 121 to the upper surface S1 is equal, and the distance from any point on the rotor core axis 121 to the lower surface S2 is also equal. That is, along the direction of the rotor core axis 121, the radial thickness of the upper surface S1 and lower surface S2 is the same at all points. In other words, the curvature of the upper surface S1 and lower surface S2 of the permanent magnet 11 is the same at all points along the direction of the rotor core axis 121, ensuring uniform thickness of the permanent magnet 11 and thus maintaining stable operation of the permanent magnet motor. Adjacent permanent magnets 11 attract each other, or adjacent permanent magnets may have opposite polarities.
[0041] In some embodiments, the radial thickness of the permanent magnet 11 provided in this application gradually increases from a first thickness D1 to a second thickness D2 in the direction from the first end 111 along the circumference of the rotor core 12 to the second end 112, or gradually increases from the first thickness D1 to a maximum thickness Dmax and then decreases to the second thickness D2.
[0042] Specifically, refer to Figure 2The permanent magnet 11 is composed of partial annular magnetic steel, and the radial thickness of the partial annular magnetic steel is uniform and equal. The upper surface S1 and the lower surface S2 of the permanent magnet 11 are arc surfaces, and the portion close to the first end 111 is polished to reduce the thickness, and the portion close to the second end 112 can be polished to reduce the thickness, so that the first end 111 extends to the second end 112 along the upper surface S1 and the lower surface S2 of the permanent magnet 11, and there is a position along the radial direction where the maximum thickness Dmax exists. Alternatively, the portion close to the second end 112 is not polished, so that the radial thickness gradually increases from the first end 111 to the second end 112.
[0043] In some embodiments, the first end 111 is provided with a first upper edge 111a and a first lower edge 111b, and the axis 121 of the rotor core 12 is arranged on the plane extending from the first upper edge 111a to the first lower edge 111b, so that the first upper edge 111a, the first lower edge 111b and the axis 121 of the rotor core 12 are coplanar; wherein the first upper edge 111a and the first lower edge 111b are parallel to each other, and the distance between the first upper edge 111a and the first lower edge 111b constitutes the first thickness D1.
[0044] Referring to Figure 2 and Figure 3 In some specific embodiments, the raw material of the permanent magnet 11 is magnetic steel, and the upper surface S1 and the lower surface S2 of the rotor core 12 are cut radially to form the first end 111, that is, in the cross section perpendicular to the axis 121 of the rotor core 12, the center P1 of the rotor core 12 is arranged in the direction of the line connecting the first upper edge 111a and the first lower edge 111b, so as to ensure that the plane where the first upper edge 111a and the first lower edge 111b are located passes through the axis 121 of the rotor core 12. Thus, the assembly difficulty of the permanent magnet 11 of the permanent magnet motor is reduced.
[0045] In some embodiments, the second end 112 is provided with a second upper edge 112a and a second lower edge 112b, and the axis 121 of the rotor core 12 is arranged on the plane extending from the second upper edge 112a to the second lower edge 112b, so that the second upper edge 112a, the second lower edge 112b and the axis 121 of the rotor core 12 are coplanar; wherein the second upper edge 112a and the second lower edge 112b are parallel to each other, and the distance between the second upper edge 112a and the second lower edge 112b constitutes the second thickness D2.
[0046] Referring to Figure 2 , Figure 3 and Figure 5In some specific embodiments, the permanent magnet 11 is made of magnetic steel, and the rotor core 12 is cut radially from the upper surface S1 and the lower surface S2 to form the second end 112, that is, in the cross section perpendicular to the axis 121 of the rotor core 12, the center P1 of the rotor core 12 is arranged in the direction of the line connecting the second upper edge 112a and the second lower edge 112b, so as to ensure that the planes where the second upper edge 112a and the second lower edge 112b are located pass through the axis 121 of the rotor core 12, thereby reducing the assembly difficulty of the permanent magnet 11 of the permanent magnet motor.
[0047] In some specific embodiments, the outer surface of the rotor core 12 is provided with a plurality of grooves, which can be dovetail grooves, and the number of the grooves is the same as that of the permanent magnets 11, so that each groove can accommodate each permanent magnet 11. The two sides of each groove are attached to the first end 111 and the second end 112, that is, the two sides of each groove are coplanar with the axis 121 of the rotor core 12.
[0048] In some embodiments, the lower surface S2 of the permanent magnet motor provided by the application is a right circular cylindrical surface, and the axis of the lower surface S2 of the permanent magnet 11 is coaxially arranged with the axis 121 of the rotor core 12. Specifically, referring to Figure 4 and Figure 5 , the lower surface S2 of the permanent magnet 11 of the permanent magnet motor is a right circular cylindrical surface, and the axis of the lower surface S2 of the permanent magnet 11 is coaxially arranged with the axis 121 of the rotor core 12, so as to be attached to the outer surface of the rotor core 12 which is also a right circular cylindrical surface.
[0049] In some embodiments, the upper surface S1 of the permanent magnet 11 provided by the application is a right circular cylindrical surface, wherein the axis of the upper surface S1 of the permanent magnet 11 is arranged parallel to the axis 121 of the rotor core 12; wherein the axis of the upper surface S1 of the permanent magnet 11 is not coincident with the axis 121 of the rotor core 12. Specifically, referring to Figure 4 and Figure 5 , the upper surface S1 and the lower surface S2 of the permanent magnet 11 of the permanent magnet motor are both right circular cylindrical surfaces, but the axes of the upper surface S1 and the lower surface S2 are parallel and not coincident, so as to ensure that the upper surface S1 and the lower surface S2 are both right circular cylindrical surfaces, and the thicknesses of the first end 111 and the second end 112 are different. In some specific embodiments, the radius R2 of the upper surface S1 is smaller than the radius R1 of the lower surface S2. In some specific embodiments, the axis of the upper surface S1 is arranged parallel between the upper surface S1 and the axis 121 of the rotor core 12.
[0050] In some embodiments, the first thickness D1 of the permanent magnet motor provided by the application is greater than or equal to half of the second thickness D2.
[0051] In some embodiments, the first thickness D1 of the permanent magnet motor provided by the application is greater than or equal to 2 mm, and the first thickness D1 is less than 4.5 mm.
[0052] The first thickness D1
[0053] Specifically, referring to Figure 2 , the first thickness D1 of the permanent magnet 11 is set to be at least equal to half of the second thickness D2. Taking the first thickness D1 as 2.5 mm and the second thickness D2 as 5 mm as an example, the torque ripple of the permanent magnet 11 with uneven thickness provided by the application is 0.04737 MxVw, and the cogging torque ripple is 0.1056 Ce, 0.1088 Vw. The torque ripple of the permanent magnet 11 with the upper surface S1 and the lower surface S2 being part of a circular ring under the conventional setting is 0.54887 MsVw, and the cogging torque ripple is 0.50479 Ce, 0.49316 Vw. Or the permanent magnet 11 with two sides of the corner under the conventional setting, taking the two sides of the corner 1.2 mm as an example, the torque ripple is 0.28928 MsVw, and the cogging torque ripple is 0.27705 Ce, 0.29644 Vw; taking the two sides of the corner 3 mm as an example, the torque ripple is 0.1236 MsVw, and the cogging torque ripple is 0.12957 Ce, 0.12638 Vw. In summary, the permanent magnet 11 provided by the application can effectively suppress the torque ripple when applied to the permanent magnet motor.
[0054] In some special embodiments, referring to Figure 5 , the permanent magnet 11 of the permanent magnet motor provided by the application is arranged on the outer surface of the rotor core 12 in sequence, which can be that the second end 112 of any permanent magnet 11 is arranged close to the first end 111 of the adjacent permanent magnet 11, and the extension direction of the second end 112 of the permanent magnet 11 to the first end 111 is the same as the rotation direction of the rotor core 12. The permanent magnet 11 provided by the application is arranged on the outer surface of the rotor core 12 in the same direction, so as to simplify the assembly difficulty. In particular, the permanent magnet 11 is arranged in pairs on the outer surface of the rotor core 12, and the first end 111 of the two permanent magnets 11 in the pair, such as the permanent magnet 11a and the permanent magnet 11b, is arranged close to each other, or the second end 112 of the two permanent magnets 11a and 11b in the pair is arranged close to each other.
[0055] In some embodiments, the maximum thickness Dmax of the permanent magnet 11 of the permanent magnet motor provided by the application along the radial direction of the rotor core 12 is greater than or equal to the second thickness D2.
[0056] Specifically, referring to Figure 2 and Figure 5, the maximum thickness Dmax of the permanent magnet 11 is located on the plane of the axis of the upper surface S1 and the axis of the lower surface S2. In the cross section perpendicular to the axis 121 of the rotor core 12, the angle between the ray extending from the first lower edge 111b to the first upper edge 111a and the straight line of the center P2 of the upper surface S1 and the center P1 of the lower surface S2 is greater than the angle between the ray extending from the second lower edge 112b to the second upper edge 112a and the straight line of the center P2 of the upper surface S1 and the center P1 of the lower surface S2, and the radius R2 of the upper surface S1 is less than the radius R1 of the lower surface S2. When the maximum thickness Dmax is equal to the second thickness D2, the straight line of the center P2 of the upper surface S1 and the center P1 of the lower surface S2 coincides with the straight line of the connection between the second upper edge 112a and the second lower edge 112b.
[0057] In some embodiments, the permanent magnet motor provided by the application further comprises a stator assembly 20 coaxially sleeved outside the rotor assembly; wherein
[0058] The stator assembly 20 comprises a stator core 21 and a winding 22, the stator core 21 is provided with a ring yoke 21a, the ring yoke 21a extends in the direction of the axis 121 of the rotor core 12 and is provided with a plurality of teeth 21b, the teeth 21b are provided with arc surfaces in the direction close to the rotor assembly, and the arc surfaces are coaxially arranged with the rotor core 12; gaps are arranged between adjacent teeth 21b, and the winding 22 is wound on the teeth 21b through the gaps; there is an air gap d between any permanent magnet 11 and any tooth 21b.
[0059] The stator assembly 20 provided by the application comprises a stator core 21 and a winding 22, the stator core 21 is provided with a ring yoke 21a and teeth 21b, the ring yoke 21a extends in the direction of the axis 121 of the rotor core 12 as a base to form a plurality of teeth 21b, the radial section of the teeth 21b is narrow close to the ring yoke 21a and wide close to the rotor core 12, and the end surface close to the rotor core 12 is provided with an arc surface, which can be a right circular cylindrical surface or a surface with the same shape as the rotor core 12. An air gap d is arranged between any tooth 21b and any permanent magnet 11, so that the rotor assembly does not contact the stator assembly 20 at any position during rotation, ensuring the normal operation of the permanent magnet motor. Gaps are arranged between adjacent teeth 21b, i.e. gaps are arranged between the roots of the teeth 21b close to the ring yoke 21a to accommodate the winding 22 wound on the stator core 21.
[0060] In some embodiments, the ratio of the minimum value of the air gap d to the radius of the arc surface of the tooth 21b is 0.002 to 0.0053.
[0061] The stator assembly 20 of the permanent magnet motor provided by the application is arranged on the outside of the rotor assembly and coaxially arranged. Specifically, referring to Figure 6 , the air gap d exists between the stator assembly 20 and the rotor assembly, that is, the air gap d exists between the permanent magnet 11 of the rotor assembly and the tooth 21b of the stator core 21 of the stator assembly 20, and the ratio of the minimum value of the air gap d to the radius of the arc surface of the tooth 21b is 0.002 to 0.0053. The coaxial arrangement of the stator assembly 20, the rotor assembly and the air gap d can ensure the normal rotation of the rotor assembly. In particular, the maximum thickness Dmax can also be arranged at the second end 112, that is, the thickness of the permanent magnet 11 is arranged from small to large from the first end 111 to the second end 112.
[0062] In some embodiments, the rotor assembly of the permanent magnet motor provided by the application further comprises a rotating shaft, the rotating shaft is arranged through the rotor core 12, and the rotating shaft is coaxially arranged with the rotor core 12 and the stator core 21; the rotating shaft is fixedly arranged relative to the rotor core 12.
[0063] Specifically, referring to Figure 1 , Figure 4 , Figures 7 to 9 , the rotating shaft, as a part of the rotor assembly, is arranged through the axis 121 of the rotor core 12, and the rotor core 12 is coaxially arranged with the stator core 21, that is, the rotating shaft is also arranged on the axis 121 of the stator core 21. So that the rotating shaft can rotate relative to the stator assembly 20 to output torque.
[0064] In some embodiments, the permanent magnet motor provided by the application further comprises a bearing 30 and a shell 40; the shell 40 is internally provided with a containing cavity, and the bearing 30 is contained in the containing cavity; the bearing 30 is sleeved on the rolling shaft 13, and the bearing 30 is coaxially arranged with the rolling shaft 13; the shell 40 is also used for containing the rotor assembly and the stator assembly 20, and the rolling shaft 13 is arranged through the shell 40.
[0065] Specifically, referring to Figures 7 to 9 , the shell 40 is internally provided with a groove containing the bearing 30, the bearing 30 contained in the groove of the shell 40 is movably connected with the rotating shaft, and the rotating shaft is arranged through the shell 40 through the bearing 30, so that the torque output by the rotor assembly can be output through the rotating shaft and be limited in the space relative to the shell 40. The bearing 30 realizes the relative sliding of the rotating shaft relative to the shell 40, thereby ensuring the torque output.
[0066] In some embodiments, the permanent magnet motor provided by the application further comprises a fixing member, and the shell 40 comprises a first shell and a second shell, wherein
[0067] The first shell and the second shell are arranged outside the rotor core 12 and the stator core 21 coaxially arranged from both sides of the cover along the axial direction of the rotation axis; the fixing member is used to combine the first shell and the second shell to form the containing cavity.
[0068] Specifically, referring to Figures 7 to 9 , the fixing member passes through the first shell and the second shell along the dotted line respectively, thereby screwing the first shell and the second shell to form the containing cavity. The fixing member can be a bolt, and the first shell and the second shell are provided with threaded through holes. Taking any fixing member as an example, the bolt is screwed into the first shell and the second shell in sequence, so as to accommodate the stator assembly 20, the rotor assembly and the bearing 30 into the containing cavity between the first shell and the second shell. In particular, a soft pad is arranged between the bolt, the nut and the first shell, thereby ensuring the stable connection of the bolt and the shell 40.
[0069] In one complete embodiment, the rotor assembly of the permanent magnet motor provided by the present application comprises a rotor core 12 and a plurality of permanent magnets 11 attached to the rotor core 12. The permanent magnet 11 is provided with an upper surface S1 and a lower surface S2, and the lower surface S2 is attached to the outer surface of the rotor core 12, that is, the shape of the lower surface S2 of the permanent magnet 11 is the same as the outer surface of the rotor core 12. The upper surface S1 and the lower surface S2 of the permanent magnet 11 are not parallel, so that the distance between the upper surface S1 and the lower surface S2 along the radial direction of the rotor core 12, that is, the thickness of the permanent magnet 11 along the radial direction of the rotor core 12, is not uniform. The two sides connecting the upper surface S1 and the lower surface S2 are the first end 111 and the second end 112, respectively, and the thickness of the first end 111 is less than the second thickness D2. The upper surface S1 and the lower surface S2 can both be a right circular cylinder, which is convenient for processing the permanent magnet 11. In order to ensure that the upper surface S1 and the lower surface S2 of the permanent magnet 11 are not parallel and the thickness of the first end 111 and the second end 112 are different, the axis positions of the upper surface S1 and the lower surface S2 cannot coincide, and the axis of the upper surface S1 should be located between the axis of the lower surface S2 and the lower surface S2, so as to ensure that there is a maximum thickness Dmax between the first end 111 and the second end 112, which should be greater than the second thickness, so that the thickness of the permanent magnet 11 increases first and then decreases along the outer periphery of the rotor core 12 from the first end 111 to the second end 112. The first end 111 and the second end 112 are arranged to connect the upper surface S1 and the lower surface S2 along the radial direction of the rotor core 12. The upper surface S1 can be arranged as other curved surfaces that are not right circular cylinders, but it should be ensured that the thickness of the first end 111 is less than that of the second end 112, and there is a maximum thickness Dmax greater than the thickness of the second end 112. In particular, the thickness of the first end 111 is half of the thickness of the second end 112, and the thickness of the first end 111 can be 2mm or 2.5mm. The thickness of the second end 112 is correspondingly set to 4mm or 5mm. The arrangement of adjacent permanent magnets 11 on the rotor core 12 is that the first end 111 of one permanent magnet 11 is close to the second end 112 of another permanent magnet 11, and the direction from the second end 112 to the first end 111 along the lower surface S2 is equivalent to the rotation direction of the rotor core 12. In particular, the permanent magnets 11 are arranged in pairs, and the first ends 111 of the permanent magnets 11a and 11b in each pair are arranged close to each other, or the second ends 112 of the permanent magnets 11a and 11b in each pair are arranged close to each other. However, it should be ensured that the polarities of adjacent permanent magnets 11 are opposite.
[0070] It can be understood that the cross section of a conventional permanent magnet 11 along the radial direction of the rotor core 12 is a partial circular ring, and the cross-sectional area of the partial circular ring is related to the magnetic flux of the motor. The cross-sectional area of the permanent magnet 11 provided by the present application should be equal to the maximum cross-sectional area of the conventional permanent magnet 11, so as to ensure that the cogging torque is improved while the output power of the permanent magnet motor using the rotor assembly provided by the present application is also ensured.
[0071] The rotor core 12 is provided with grooves adapted to the permanent magnets 11, so that the permanent magnets 11 can be embedded in the grooves to be fixed on the outer surface of the rotor core 12. The grooves provided on the rotor core 12 are of the same pitch, ensuring the stability of the rotor assembly in the working state. The grooves can be dovetail grooves to simplify the assembly of the permanent magnets 11. The rotor assembly can be provided with two end cover plates to cover the rotor core 12 in the direction of the axis 121 of the rotor core 12, thereby providing support for the permanent magnets 11 fixed on the rotor core 12.
[0072] The permanent magnets 11 are assembled on the outer periphery of the rotor core 12 and can be fixed by glue, a ferrule, or the grooves and cover plates as shown in the present application. The rotor core 12 is of a hollow structure. The rotor assembly further comprises a rotating shaft which penetrates the rotor core 12 and is coaxially arranged with the rotor core 12. Bearings 31 and 32 are sleeved on the rotating shaft on both sides of the rotor core 12. The bearings 31 and 32 are simultaneously contained in the housing 40 of the permanent magnet motor, so that the rotor assembly can rotate relative to the housing 40 through the bearings 31 and 32. At the same time, the stator assembly 20 is also contained in the housing 40 of the permanent magnet motor. Specifically, the stator assembly 20 is sleeved on the outer periphery of the rotor assembly and is coaxially arranged with the rotor assembly while maintaining an air gap d, the ratio of the minimum value of the air gap d to the radius of the arc surface of the tooth 21b being 0.002 to 0.0053, the maximum thickness Dmax of the stator assembly 20 being 150 mm. In particular, the minimum width of the air gap d is 0.3 mm-0.8 mm, and the inner diameter of the stator assembly 20 is 150 mm. The stator assembly 20 is provided with a stator core 21 and a winding 22, and the winding 22 is wound around the stator core 21.
[0073] It should be noted that all the technical features above can be freely combined without conflict, and the free combination or simple modification, change and modification thereof are within the protection scope of the present patent.
[0074] All the technical features of all the components above can be freely combined without conflict, and the free combination or simple modification, change and modification thereof are within the protection scope of the present patent.
[0075] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "yet another embodiment", "another embodiment", "other embodiments", "example", "specific example" or "some examples" etc. means that the particular feature, structure, material or characteristic being described in connection with the embodiment or example is included in at least one embodiment or example of the application. The illustrative appearance of the above terms in various places in the specification are not necessarily intended to refer to the same embodiment or example. Moreover, the particular features, structures, materials or characteristics can be combined in any suitable manner in one or more embodiments or examples. Furthermore, persons skilled in the art can combine different embodiments or examples described in the specification.
[0076] Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary, and are not to be interpreted as limiting the present application, and the ordinary skilled person in the art can make changes, modifications and variations to the above embodiments within the scope of the present application.
Claims
1. A permanent magnet electric machine comprising a rotor assembly, characterized by, The application relates to a permanent magnet motor. The rotor assembly comprises a rotor core and a plurality of permanent magnets, the permanent magnets are arranged in pairs on the outer surface of the rotor core in sequence, any permanent magnet is provided with an upper surface and a lower surface; wherein the upper surfaces of the permanent magnets adjacent in the circumferential direction of the outer surface of the rotor core are opposite in polarity, the lower surfaces of the two permanent magnets adjacent in the circumferential direction of the outer surface of the rotor core are opposite in polarity. The upper surface of the permanent magnet is arranged away from the axis of the rotor core relative to the lower surface of the permanent magnet; the upper surface of the permanent magnet is connected to the lower surface of the permanent magnet through a first end and a second end respectively; the first thickness of the first end in the radial direction of the rotor core is smaller than the second thickness of the second end in the radial direction of the rotor core.
2. The permanent magnet electric machine of claim 1, wherein, The thickness of the permanent magnet in the radial direction gradually increases from the first thickness to the second thickness in the direction from the first end to the second end along the circumferential direction of the rotor core, or gradually increases from the first thickness to the maximum thickness and then decreases to the second thickness.
3. The permanent magnet electric machine of claim 1, wherein, The first end is provided with a first upper edge and a first lower edge, the axis of the rotor core is arranged on the plane extending from the first upper edge to the first lower edge, so that the first upper edge, the first lower edge and the axis of the rotor core are coplanar; wherein the first upper edge and the first lower edge are parallel to each other, and the distance between the first upper edge and the first lower edge constitutes the first thickness.
4. The permanent magnet electric machine of claim 1, wherein, The second end is provided with a second upper edge and a second lower edge, the axis of the rotor core is arranged on the plane extending from the second upper edge to the second lower edge, so that the second upper edge, the second lower edge and the axis of the rotor core are coplanar; wherein the second upper edge and the second lower edge are parallel to each other, and the distance between the second upper edge and the second lower edge constitutes the second thickness.
5. A permanent magnet electric machine according to any one of claims 3 or 4, characterized in that, The lower surface of the permanent magnet is arranged as a right circular cylindrical surface, and the axis of the lower surface of the permanent magnet is coaxially arranged with the axis of the rotor core.
6. The permanent magnet electric machine of claim 5, wherein, The upper surface of the permanent magnet is arranged as a right circular cylindrical surface, wherein the axis of the upper surface of the permanent magnet is arranged parallel to the axis of the rotor core; wherein the axis of the upper surface of the permanent magnet does not coincide with the axis of the rotor core.
7. The permanent magnet electric machine of claim 1, wherein, The first thickness is greater than or equal to half of the second thickness.
8. The permanent magnet electric machine of claim 7, wherein, The first thickness is greater than or equal to 2mm and less than 4.5mm.
9. The permanent magnet electric machine of claim 1, wherein, The maximum thickness of the permanent magnet in the radial direction of the rotor core is greater than or equal to the second thickness.
10. The permanent magnet electric machine of claim 1, wherein, The permanent magnet motor further comprises a stator assembly, the stator assembly is coaxially sleeved on the outside of the rotor assembly; wherein The stator assembly comprises a stator core and a winding, the stator core is provided with a ring yoke portion, the ring yoke portion extends in the direction of the axis of the rotor core and is provided with a plurality of teeth, the teeth are provided with an arc surface in the direction close to the rotor assembly, the arc surface is coaxially arranged with the rotor core; gaps are arranged between adjacent teeth, the winding is wound on the teeth through the gaps; there is an air gap between any permanent magnet and any tooth.
11. The permanent magnet electric machine of claim 10, wherein, The ratio of the minimum value of the air gap to the radius of the arc surface of the tooth is 0.002 to 0.0053.
12. The permanent magnet electric machine of claim 10, wherein, The rotor assembly further comprises a rotating shaft, which is arranged through the rotor core and coaxially arranged with the rotor core and the stator core; the rotating shaft is fixedly arranged relative to the rotor core.
13. The permanent magnet electric machine of claim 12, wherein, The permanent magnet motor further comprises a bearing and a shell; the shell is internally provided with a containing cavity, the bearing is contained in the containing cavity, the bearing is sleeved on the rotating shaft, and the bearing is coaxially arranged with the rotating shaft; the shell is further used for containing the rotor assembly and the stator assembly, and the rotating shaft is arranged through the shell.
14. The permanent magnet electric machine of claim 13, wherein, The permanent magnet motor further comprises a fixing member, and the shell comprises a first shell and a second shell, wherein The first shell and the second shell are arranged on the outer sides of the coaxially arranged rotor core and stator core from both sides along the axial direction of the rotating shaft; and the fixing member is used for combining the first shell and the second shell to form the containing cavity.