Rotor core, rotor assembly, motor and household appliance

Abstract

The invention discloses a rotor iron core, a rotor assembly, a motor and a household electrical appliance, and relates to the technical field of motors, the rotor iron core rotates around a rotation axis, the rotor iron core comprises one or more magnet yoke segments, each magnet yoke segment comprises a plurality of magnet yoke units and a plurality of bending parts, the plurality of magnet yoke units are sequentially arranged in the direction around the rotation axis, and the bending parts are arranged in the direction around the rotation axis. Each magnet yoke section comprises a plurality of bent parts, each bent part is connected between two adjacent magnet yoke units, the width of each bent part is smaller than that of each magnet yoke unit in the radial direction of the rotor iron core, and the magnet yoke section further comprises two butt joint parts which are located at the two ends of the magnet yoke section in the direction around the rotating axis respectively; wherein the one or more magnet yoke sections are connected into a ring shape through the butt joint parts. The rotor core is easy to produce and low in production cost.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a rotor core, a rotor assembly, a motor and a household appliance. Background Art

[0002] The rotor core of a motor is typically made from cold-rolled steel sheets, perhaps through a winding process to form a ring. However, this method is complex and difficult to manufacture, and it is difficult to control the roundness of the rotor core, resulting in high processing costs. Another approach is to use a lamination process to produce multiple annular punchings from cold-rolled steel sheets, which are then stacked to form a ring-shaped rotor core. However, this method produces a large amount of scrap, resulting in material waste and high material costs. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a rotor core that is easy to produce and has low production cost.

[0004] The present invention also provides a rotor assembly, a motor and a household appliance having the rotor core.

[0005] According to the rotor core of the embodiment of the first aspect of the present invention, it rotates around the axis of rotation and includes one or more yoke segments, wherein the yoke segment includes multiple yoke units and multiple bent portions, and the multiple yoke units are arranged in sequence along the direction around the axis of rotation, and each of the bent portions is connected between two adjacent yoke units. Along the radial direction of the rotor core, the width of the bent portion is smaller than the width of the yoke unit. The yoke segment also includes two docking portions, which are respectively located at the two ends of the yoke segment along the direction around the axis of rotation; wherein, one or more yoke segments are connected into a ring shape through the docking portions.

[0006] The rotor core according to the embodiment of the first aspect of the present invention has at least the following beneficial effects: since the yoke segment is formed by connecting multiple yoke units through a bending portion, and the width of the bending portion is smaller than the width of the yoke unit in the radial direction, the bending portion is easy to bend. When processing the yoke segment, a yoke segment with multiple yoke units arranged linearly can be first processed so that they can be tightly arranged on the silicon steel plate, thereby reducing waste, improving material utilization, and helping to reduce material costs; then the yoke segment is bent at the bending portion so that the yoke segment is annular or arc-shaped, and finally one or more yoke segments are connected to form an annular rotor core through a docking portion. The rotor core has good integrity, can reduce the number of parts, has a simple production process, is conducive to reducing production difficulty, and is easy to ensure the roundness of the rotor core, thereby reducing process costs. Therefore, the overall production cost of the rotor core is reduced.

[0007] According to some embodiments of the present invention, along the radial direction of the rotor core, the bent portion is connected to a side of the yoke unit away from the rotation axis.

[0008] According to some embodiments of the present invention, a stress release groove is provided between two adjacent yoke units of the yoke segment, and the stress release groove is located on a side of the bent portion close to the rotation axis.

[0009] According to some embodiments of the present invention, adjacent butting portions are fixed by welding.

[0010] According to some embodiments of the present invention, one of the two docking portions of the yoke segment is configured as a slot, and the other docking portion is configured as a buckle that cooperates with the slot.

[0011] According to some embodiments of the present invention, the slot width increases gradually from the slot opening to the slot bottom.

[0012] According to some embodiments of the present invention, the slot width first increases and then decreases from the slot opening to the slot bottom.

[0013] According to an embodiment of the second aspect of the present invention, the rotor assembly includes the rotor core of the embodiment of the first aspect of the present invention and a plurality of permanent magnets, wherein the plurality of permanent magnets are arranged at intervals along the circumference of the rotor core, and the permanent magnets are arranged on a side of the rotor core close to the rotation axis.

[0014] According to the rotor assembly of the second embodiment of the present invention, there are at least the following beneficial effects: since the rotor assembly adopts the above-mentioned rotor core, since the yoke segment is formed by connecting multiple yoke units through a bend portion, and the width of the bend portion is smaller than the width of the yoke unit in the radial direction, the bend portion is easy to bend. When processing the yoke segment, a yoke segment with multiple yoke units arranged linearly can be first processed so that they can be closely arranged on the silicon steel sheet, thereby reducing waste, improving material utilization, and helping to reduce material costs; then the yoke segment is bent at the position of the bend portion so that the yoke segment is annular or arc-shaped, and finally one or more yoke segments are connected to form an annular rotor core through the docking portion. The rotor core has good integrity, can reduce the number of parts, has a simple production process, is conducive to reducing production difficulty, and is easy to ensure the roundness of the rotor core, thereby reducing process costs. Therefore, the overall production cost of the rotor core and the rotor assembly is reduced.

[0015] According to some embodiments of the present invention, the number of the yoke units is N, and the number of the permanent magnets is M, satisfying: M is an integer multiple of N.

[0016] According to some embodiments of the present invention, the permanent magnet has a center line arranged along the radial direction of the rotor core, and the center line passes through the bending portion or the joint between two adjacent joint portions.

[0017] The motor according to the third embodiment of the present invention includes a stator assembly and a rotor assembly according to the second embodiment of the present invention, wherein the rotor assembly is wound around the outer circumference of the stator assembly.

[0018] The motor according to the third embodiment of the present invention has at least the following beneficial effects: since the motor adopts the above-mentioned rotor assembly, since the yoke segment is formed by connecting multiple yoke units through a bending portion, and the width of the bending portion is smaller than the width of the yoke unit in the radial direction, the bending portion is easy to bend. When processing the yoke segment, a yoke segment with multiple yoke units arranged linearly can be first processed so that they can be closely arranged on the silicon steel plate, thereby reducing waste, improving material utilization, and helping to reduce material costs; then the yoke segment is bent at the position of the bending portion so that the yoke segment is annular or arc-shaped, and finally one or more yoke segments are connected to form an annular rotor core through the docking portion. The rotor core has good integrity, can reduce the number of parts, has a simple production process, is conducive to reducing production difficulty, and is easy to ensure the roundness of the rotor core, thereby reducing process costs. Therefore, the overall production cost of the rotor core and the motor is reduced.

[0019] A household appliance according to an embodiment of a fourth aspect of the present invention includes the motor according to the embodiment of the third aspect of the present invention.

[0020] According to the household appliance of the fourth embodiment of the present invention, there are at least the following beneficial effects: since the household appliance adopts the above-mentioned motor, since the yoke segment is formed by connecting multiple yoke units through a bending portion, and the width of the bending portion is smaller than the width of the yoke unit in the radial direction, the bending portion is easy to bend. When processing the yoke segment, a yoke segment with multiple yoke units arranged linearly can be first processed so that they can be closely arranged on the silicon steel plate, thereby reducing waste, improving material utilization, and helping to reduce material costs; then the yoke segment is bent at the position of the bending portion so that the yoke segment is annular or arc-shaped, and finally one or more yoke segments are connected to form an annular rotor core through the docking portion. The rotor core has good integrity, can reduce the number of parts, has a simple production process, is conducive to reducing production difficulty, and is easy to ensure the roundness of the rotor core, thereby reducing process costs. Therefore, the overall production cost of the rotor core and the household appliance is reduced.

[0021] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0023] Figure 1 is a schematic diagram of the motor axial direction in some embodiments of the present invention;

[0024] Figure 2 yes Figure 1 A magnified view of point A in the figure;

[0025] Figure 3 is a schematic structural diagram of a straight-strip yoke segment in some embodiments of the present invention;

[0026] Figure 4 yes Figure 3 A partial schematic diagram of the middle yoke section;

[0027] Figure 5 is a schematic diagram of the connection between two yoke segments in other embodiments of the present invention;

[0028] Figure 6 is a schematic diagram of the connection between two yoke segments in other embodiments of the present invention;

[0029] Figure 7 is an axial schematic diagram of a rotor core in other embodiments of the present invention;

[0030] Figure 8 is an axial schematic diagram of a rotor core in other embodiments of the present invention;

[0031] Figure 9 This is a schematic diagram of silicon steel plate arrangement in an embodiment of the present invention;

[0032] Figure 10 Schematic diagram of the distribution of some magnetic flux lines in the rotor assembly in an embodiment of the present invention.

[0033] Reference numerals:

[0034] Rotor assembly 1000; stator assembly 2000;

[0035] Rotor core 100;

[0036] Magnetic yoke section 200; yoke unit 210; bent portion 220; docking portion 230; slot 231; first wall 2311; second wall 2312; buckle 232; stress relief slot 240;

[0037] Permanent magnet 300;

[0038] Silicon steel plate 400; punching segment 410;

[0039] Centerline Z. DETAILED DESCRIPTION

[0040] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0041] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0042] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0043] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, assembling, and matching should be understood in a broad sense. Technical personnel in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0044] As an important component of household appliances such as air conditioners, washing machines, and refrigerators, the performance and production costs of motors affect these appliances to a certain extent. Motors generally include outer rotor motors and inner rotor motors. For outer rotor motors, their rotor cores are usually annular and wound around the outer circumference of the stator. Generally speaking, the rotor core is made of cold-rolled steel sheet. In related technologies, for example, cold-rolled steel sheet (such as silicon steel sheet) is processed into an annular shape through a winding process. However, this processing method is complex and difficult to process. It is also difficult to control the roundness of the rotor core, which affects assembly and motor performance, and the processing cost is relatively high. For example, the rotor core is processed through a lamination process. First, an annular punching is punched out of the cold-rolled steel sheet. Then, multiple punchings are stacked in sequence along the direction of the rotor's rotation axis to form an annular rotor core. However, the annular shape of the punching is not conducive to sample arrangement. On the other hand, it will generate a lot of waste, resulting in low material utilization, material waste, and high material costs.

[0045] For this purpose, refer to Figures 1 to 10As shown, a first embodiment of the present invention provides a rotor core 100. The rotor core 100 is a component of a rotor assembly 1000 and is specifically applied to a motor of a household appliance, which may be an air conditioner, a washing machine, a refrigerator, etc. The motor is an outer rotor motor.

[0046] Reference Figure 1 As shown, it can be understood that the motor includes a rotor assembly 1000 and a stator assembly 2000. The rotor assembly 1000 is arranged around the outer circumference of the stator assembly 2000 and can rotate relative to the stator assembly 2000. The central axis of the rotor assembly 1000 is the rotation axis of the rotor assembly 1000.

[0047] Reference Figure 1 As shown, it can be understood that the rotor assembly 1000 includes a rotor core 100 and a plurality of permanent magnets 300. Specifically, the rotation axis of the rotor assembly 1000 is the rotation axis of the rotor core 100. The rotor core 100 is annular and is formed by connecting one or more yoke segments 200.

[0048] It is understood that the rotor core 100 is composed of multiple rotor laminations stacked along the rotation axis. Consequently, the yoke segment 200 is also composed of multiple lamination segments 410 stacked along the rotation axis. One or more coplanar lamination segments 410 form a rotor lamination. Therefore, when producing the rotor core 100, it is necessary to first punch out multiple lamination segments 410 from the silicon steel sheet 400.

[0049] Reference Figures 2 to 4 As shown, it can be understood that the yoke segment 200 includes multiple yoke units 210 and multiple bent portions 220. Specifically, on a projection plane perpendicular to the rotation axis, the projection of each yoke unit 210 is a sector ring, that is, a portion of a ring. The central angle between the inner and outer contours of the sector ring is approximately 30°, making the projection of each yoke unit 210 generally an elongated structure. Here, the inner side refers to the side closer to the rotation axis, and the outer side refers to the side farther from the rotation axis.

[0050] Reference Figure 1 and Figure 3As shown, it can be understood that in each yoke segment 200, the number of bent portions 220 is one less than the number of yoke units 210. Multiple yoke units 210 are sequentially connected via the bent portions 220, i.e., each bent portion 220 has two ends connected to two adjacent yoke units 210, resulting in a chain-like structure for the yoke segment 200. Along the radial direction of the rotor core 100, the width of the bent portion 220 is smaller than the width of the yoke units 210. The width of the bent portion 220 is the distance between two radially opposing walls of the bent portion 220 along the rotor core 100, i.e., W1; the width of the yoke units 210 is the distance between two radially opposing walls of the yoke units 210, i.e., W2. Therefore, the bent portion 220 is more flexible than the yoke units 210 and can bend perpendicular to the rotation axis, allowing folding between adjacent yoke units 210. For example, the yoke segment 200 in which the plurality of yoke units 210 are arranged linearly is bent into an arc or a circle.

[0051] Reference Figure 9 As shown, it can be understood that when producing the yoke segment 200, a straight strip-shaped punch segment 410 can be first punched out from the silicon steel sheet 400. Multiple punch segments 410 are then stacked sequentially along the direction of the rotation axis to form a yoke segment 200 with multiple yoke units 210 arranged linearly. The yoke segment 200 is then bent into an arc or ring shape, i.e., multiple yoke units 210 are distributed in a ring or arc shape. The multiple yoke units 210 are then connected sequentially along the direction around the rotation axis for further processing into the rotor core 100. Because the punch segments 410 are all straight strips, the multiple punch segments 410 can be densely arranged on the silicon steel sheet. This dense arrangement helps reduce the amount of sheet material between adjacent punch segments 410, thereby reducing waste, improving the material utilization rate of the silicon steel sheet 400, and thus reducing material costs. In addition, the multiple yoke units 210 are connected into a whole via the bent portion 220, which improves integrity, reduces the number of parts, and simplifies the process.

[0052] Reference Figure 2 and Figure 3 As shown, it can be understood that the yoke segment 200 also includes docking portions 230 located at both ends along the length direction. The length direction of the yoke segment 200 is the arrangement direction of the multiple yoke units 210, or the circumferential direction of the rotor core 100. The circumferential direction of the rotor core 100 is the direction around the rotation axis. In other words, the yoke segment 200 includes two docking portions 230, and the two docking portions 230 are located on the opposite sides of the yoke units 210 at both ends. The two docking portions 230 can both be end faces or a combination of a dovetail portion and a dovetail groove. For example, the docking portions 230 are both end faces and are connected by welding. The structure of the docking portions 230 is simple and easy to punch. The connection process of the two docking portions 230 is simple, which helps to reduce process costs.

[0053] Reference Figure 1 As shown, it can be understood that in this embodiment, the rotor core 100 includes a yoke segment 200. Specifically, the yoke segment 200 includes ten yoke units 210. The yoke segment 200 is bent into a ring shape and the butt joints 230 at both ends are interconnected, thereby forming a ring-shaped rotor core 100. Therefore, when producing the rotor core 100, a plurality of straight strip-shaped punch segments 410 are first punched out of the silicon steel sheet 400. The plurality of punch segments 410 are then stacked along the thickness direction (i.e., the direction of the rotation axis) to form the yoke segment 200. At this time, the plurality of yoke units 210 of the yoke segment 200 are linearly arranged. The entire yoke segment 200 is then bent into a ring shape, and the butt joints 230 at both ends are welded to obtain the ring-shaped rotor core 100. The simple production process helps reduce production difficulty, thereby reducing process costs. At the same time, the rotor core 100, comprising only one yoke segment 200, has improved integrity and structural strength, and features a reduced number of parts, a simpler process, and can effectively maintain the roundness of the rotor core 100, facilitating assembly of the rotor assembly 1000 and the stator assembly 2000. Furthermore, multiple straight punch segments 410 can be closely arranged on the silicon steel sheet 400. This compact arrangement helps reduce waste, improves material utilization of the silicon steel sheet 400, and thus reduces material costs. Consequently, the overall production cost of the rotor core 100 is reduced.

[0054] Reference Figure 7 As shown, in other embodiments, it is understood that the rotor core 100 includes multiple yoke segments 200. Specifically, the rotor core 100 includes two yoke segments 200. The two yoke segments 200 have the same structure, that is, the two yoke segments 200 have the same number of yoke units 210, and each yoke segment 200 includes five yoke units 210. Similarly, after multiple punch segments 410 are stacked to form a yoke segment 200, the two yoke segments 200 are bent into semicircular shapes, the two semicircular yoke segments 200 are connected end to end, and the corresponding butt joints 230 are welded to form a ring-shaped rotor core 100. Similarly, it is possible to reduce process costs and material costs and improve the material utilization rate of the silicon steel plate 400.

[0055] Reference Figure 8As shown, in other embodiments, it is understood that the rotor core 100 may also include three yoke segments 200, wherein two yoke segments 200 include three yoke units 210, and another yoke segment 200 includes four yoke units 210. Similarly, after laminating multiple punch segments 410 to form a yoke segment 200, the three yoke segments 200 are each bent into an arc shape, the three arc-shaped yoke segments 200 are sequentially connected end to end, and the corresponding joint portions 230 are welded to form an annular rotor core 100. Similarly, process and material costs can be reduced, and the material utilization rate of the silicon steel plate 400 can be improved.

[0056] Of course, it is understandable that the composition of the rotor core 100 is not limited to including the above-mentioned number of yoke segments 200 , and the number of yoke units 210 included in each yoke segment 200 is also not limited to the above description.

[0057] Reference Figure 1 and Figure 2 As shown, it can be understood that along the radial direction of the rotor core 100, the width of the bent portion 220 is smaller than the width of the yoke unit 210, thereby increasing the flexibility of the bent portion 220 and facilitating bending of the bent portion 220. This facilitates bending the straight yoke segment 200 into an arc or ring shape, facilitating production. Furthermore, the ends of the bent portion 220 along the circumferential direction of the rotor core 100 are connected to the ends of the yoke unit 210 along the circumferential direction of the rotor core 100, which are away from the rotation axis. The opposite ends of two adjacent yoke units 210 are disconnected on the sides closer to the rotation axis, thereby facilitating the bending operation of the yoke segment 200. Furthermore, the wall surface of the bent portion 220 along the radial direction of the rotor core 100, which is away from the rotation axis, forms a portion of the outer circumferential wall of the rotor core 100, making the outer circumferential wall of the rotor core 100 a continuous wall surface and facilitating roundness.

[0058] Reference Figures 2 to 4As shown, it can be understood that a stress relief groove 240 is provided between two adjacent yoke units 210 in each yoke segment 200. The stress relief groove 240 is located on the side of the bent portion 220 closest to the rotation axis. Specifically, on a projection plane perpendicular to the rotation axis, the stress relief groove 240 projects as a circular hole. Of course, the stress relief groove 240 can also project as a square hole, a waist-shaped hole, an elliptical hole, etc. The stress relief groove 240 extends through the rotor core 100 along the rotation axis. In each adjacent yoke unit 210 of each yoke segment 200, two grooves are provided on opposite sides of the two yoke units 210. The grooves project as semicircular holes on a projection plane perpendicular to the rotation axis, and the openings of the two grooves are arranged opposite each other. After the yoke segment 200 is bent into a ring or arc shape, the two oppositely arranged grooves in the two adjacent yoke units 210 of each yoke segment 200 combine to form the stress relief groove 240. Therefore, when the yoke segment 200 is bent, the presence of the stress release groove 240 can release the stress, thereby avoiding the disadvantage of the bent portion 220 being broken during the bending process and improving reliability.

[0059] Reference Figure 5 As shown, in other embodiments, it is understood that in embodiments where the rotor core 100 includes at least two yoke segments 200, two adjacent yoke segments 200 are connected by means of a dovetail portion and a dovetail slot. That is, of the two docking portions 230 of each yoke segment 200, one docking portion 230 is configured as a dovetail structure, and the other docking portion 230 is configured as a dovetail slot structure that cooperates with the dovetail structure. Specifically, of the two docking portions 230 of each yoke segment 200, one docking portion 230 is configured as a slot 231, and the other docking portion 230 is configured as a buckle 232 that cooperates with the slot 231. The buckle 232 can be accommodated in the slot 231 and achieve a snap fit, thereby connecting the two yoke segments 200 to each other. The locking groove 231 is recessed along the circumference of the rotor core 100 at one end of the yoke unit 210 , and the buckle 232 is protruded along the circumference of the rotor core 100 at the other end of the yoke unit 210 .

[0060] Reference Figure 5As shown, it can be understood that the slot 231 is defined as having a first wall surface 2311 and a second wall surface 2312 that are arranged opposite to each other along the radial direction of the rotor core 100, and the distance between the first wall surface 2311 and the second wall surface 2312 is the slot width of the slot 231. Along the circumferential direction of the rotor core 100, the slot width of the slot 231 increases from the notch of the slot 231 to the bottom of the slot. Specifically, on the projection plane perpendicular to the axis of rotation, the projection of the slot 231 is a trapezoid, and is an isosceles trapezoid. Correspondingly, the projection of the buckle 232 is also an isosceles trapezoid. Of course, it is easy to understand that the projections of the slot 231 and the buckle 232 can also be other shapes, and the projection shapes of the slot 231 and the buckle 232 need to be kept consistent, and the buckle 232 can be accommodated in the slot 231 and achieve a snap fit.

[0061] Taking the rotor core 100 including two yoke segments 200 as an example, after the two yoke segments 200 are bent into arcs, the slot 231 of the first yoke segment 200 and the buckle 232 of the second yoke segment 200 are arranged relative to each other in the circumferential direction of the rotor core 100, and the buckle 232 of the first yoke segment 200 and the slot 231 of the second yoke segment 200 are arranged relative to each other in the circumferential direction of the rotor core 100. The buckle 232 of the first yoke segment 200 is inserted into the slot 231 of the second yoke segment 200 along the direction of the rotation axis. At the same time, the buckle 232 of the second yoke segment 200 is inserted into the slot 231 of the first yoke segment 200 until the buckle 232 is completely accommodated in the slot 231. In this way, the two yoke segments 200 can be connected to form an annular rotor core 100. The connection is stable and reliable, and the assembly operation is simple, which is conducive to reducing process costs.

[0062] Similarly, when the rotor core 100 includes three or more yoke segments 200 , the three or more yoke segments 200 can be connected into a ring-shaped rotor core 100 in the same manner as described above, which will not be described in detail here.

[0063] Reference Figure 6 As shown, in other embodiments, it can be understood that, along the circumference of the rotor core 100, from the slot opening of the slot 231 to the slot bottom, the slot width of the slot 231 first increases and then decreases. For example, on the projection plane perpendicular to the rotation axis, the contour line of the projection of the slot 231 is a major arc (i.e., an arc corresponding to a circular angle greater than 180°), and correspondingly, the projection of the buckle 232 matches the projection of the slot 231. Therefore, similarly. The buckle 232 can be inserted into the slot 231 on the other yoke segment 200 along the direction of the rotation axis and realize a snap-fit ​​fit to realize the mutual connection of the two yoke segments 200. No further details will be given here.

[0064] Of course, it is understandable that in an embodiment where the rotor core 100 includes only one yoke segment 200, when the height of the yoke segment 200 along the direction of the rotation axis is relatively small, after the yoke segment 200 is bent into a ring shape, since the yoke segment 200 has a certain flexibility in the direction of the rotation axis, the clip 232 at one end of the yoke segment 200 can also be inserted into the slot 231 at the other end along the direction of the rotation axis, thereby connecting the two ends of the yoke segment 200 together to form a ring-shaped rotor core 100.

[0065] Reference Figure 1 As shown, it can be understood that in the rotor assembly 1000 of this embodiment, the multiple permanent magnets 300 are arranged at equal intervals along the circumference of the rotor core 100, and the permanent magnets 300 are located on the side of the rotor core 100 closer to the rotation axis. In other words, the multiple permanent magnets 300 are arranged at equal intervals along the circumference of the rotor core 100 on the inner circumferential wall of the rotor core 100. For example, the permanent magnets 300 are fixed to the inner circumferential wall of the rotor core 100 by adhesive. This not only facilitates the installation of the permanent magnets 300, but also eliminates the need for an iron core structure between two adjacent permanent magnets 300. In other words, the space between the two adjacent permanent magnets 300 is filled with air or an injection molded object. As can be easily understood, the magnetic resistance of air or an injection molded object is much greater than that of an iron core structure. Therefore, the magnetic flux leakage between two adjacent permanent magnets 300, namely, the inter-pole magnetic flux leakage, can be significantly reduced, thereby improving the utilization rate of the permanent magnets 300.

[0066] Reference Figure 1 As shown, it is easy to understand that in the entire rotor core 100, there are stress release grooves 240 and fine gaps at the disconnection position between a part of two adjacent yoke units 210, and between another part of two adjacent yoke units 210, there are docking parts 230 and docking parts 230, and there are also certain fine gaps between the docking parts 230 and the docking parts 230. The magnetic resistance at the stress release grooves 240 and the fine gaps is much greater than the magnetic resistance of the rotor core 100.

[0067] Reference Figure 10 As shown, it can be understood that the permanent magnet 300 is an axisymmetric structure, and the center line Z of the permanent magnet 300 is the axis of symmetry, and the center line Z of the permanent magnet 300 is arranged along the radial direction of the rotor core 100. It is easy to understand that in the rotor assembly 1000, the magnetic field formed by the permanent magnet 300 is transmitted to the rotor core 100, and the direction of most of the magnetic flux lines at the rotor core 100 is from the center line Z of the permanent magnet 300 to both sides of the center line Z along the circumferential direction of the rotor core 100. Figure 10 The dotted lines in the figure are magnetic flux lines.

[0068] Reference Figure 2 and Figure 10As shown, to avoid the magnetic flux lines from passing through the stress release slots 240 and the slits as much as possible, the center lines Z of some permanent magnets 300 are arranged in the bend portion 220. Specifically, the center lines Z of the permanent magnets 300 pass through the stress release slots 240 and the slits at the disconnection position along the radial direction of the rotor core 100, and the center lines Z of the other permanent magnets 300 pass through the joint of the docking portion 230 along the radial direction of the rotor core 100, and also pass through the slits at the joint. Therefore, it is possible to avoid a large number of magnetic flux lines passing through the stress release slots 240 and the slits, which would weaken the magnetic field, thereby reducing the weakening effect of the stress release slots 240 and the slits on the magnetic field, which is conducive to improving the utilization rate of the permanent magnets 300 and thus improving the performance of the motor. Therefore, to ensure that the spacing between multiple permanent magnets 300 is equal and to avoid the magnetic flux lines from passing through the stress release slots 240 and the slits as much as possible, the number of yoke units 210 is defined as N, and the number of permanent magnets 300 is defined as M, so that M is an integer multiple of N. That is, the number of permanent magnets 300 is an integer multiple of the number of yoke units 210. In this embodiment, there are ten yoke units 210 and ten permanent magnets 300, i.e., N = 10 and M = 10, where M is one times N. At this point, the centerline Z of each permanent magnet 300 passes through the junction of the bent portion 220 and the junction portion 230 in a one-to-one correspondence.

[0069] Of course, in other embodiments, M=10 and N=5 can be satisfied. In this case, M is twice N. For any three permanent magnets 300 arranged continuously along the circumference of the rotor core 100, the center lines of the permanent magnets 300 located at the circumferential ends of the rotor core 100 respectively pass through the joints of the bent portions 220 or the joints 230, and the center line of the permanent magnet 300 located in the middle passes through the yoke unit 210. Therefore, a large number of magnetic flux lines passing through the stress relief slots 240 and slits, which would weaken the magnetic field, can be avoided, thereby improving the utilization rate of the permanent magnets 300 and further improving the performance of the motor.

[0070] Of course, the number N of the yoke units 210 and the number M of the permanent magnets 300 can also be other combinations, as long as M is an integer multiple of N, which will not be repeated here.

[0071] The rotor assembly 1000 according to the second embodiment of the present invention includes the rotor core 100 according to the first embodiment of the present invention, which will not be described in detail here.

[0072] Since the rotor assembly 1000 adopts all the technical solutions of the rotor core 100 of the above embodiment, it has at least all the beneficial effects brought about by the technical solutions of the above embodiment.

[0073] The motor according to the third embodiment of the present invention includes the rotor assembly 1000 according to the second embodiment of the present invention, which will not be described in detail here.

[0074] Since the motor adopts all the technical solutions of the rotor assembly 1000 of the above embodiment, it has at least all the beneficial effects brought about by the technical solutions of the above embodiment.

[0075] The household appliance according to the fourth embodiment of the present invention includes the motor according to the third embodiment of the present invention, which will not be described in detail here.

[0076] Since the household appliance adopts all the technical solutions of the motor of the above embodiment, it has at least all the beneficial effects brought about by the technical solutions of the above embodiment.

[0077] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the scope of the present invention.

Claims

1. A rotor core, rotating about an axis of rotation, characterized in that: include: One or more yoke segments, each yoke segment comprising a plurality of yoke units and a plurality of bent portions, wherein the plurality of yoke units are sequentially arranged along a direction around the rotation axis, each bent portion is connected between two adjacent yoke units, and along the radial direction of the rotor core, the width of the bent portion is smaller than the width of the yoke unit. The yoke segment further comprises two butt joints, each of the butt joints being located at both ends of the yoke segment along the direction around the rotation axis; Wherein, one or more of the yoke segments are connected into a ring shape through the docking portion.

2. The rotor core according to claim 1, wherein: Along the radial direction, the bent portion is connected to a side of the yoke unit away from the rotation axis.

3. The rotor core according to claim 1 or 2, characterized in that: A stress release groove is provided between two adjacent yoke units of the yoke segment, and the stress release groove is located on a side of the bent portion close to the rotation axis.

4. The rotor core according to claim 1, wherein: The adjacent butting portions are fixed by welding.

5. The rotor core according to claim 1, wherein: Among the two docking parts of the yoke segment, one of the docking parts is configured as a slot, and the other docking part is configured as a buckle that cooperates with the slot.

6. The rotor core according to claim 5, characterized in that: The slot width increases gradually from the slot opening to the slot bottom.

7. The rotor core according to claim 5, wherein: The slot width increases first and then decreases from the slot opening to the slot bottom.

8. A rotor assembly, characterized in that include: The rotor core according to any one of claims 1 to 7; A plurality of permanent magnets are arranged at intervals along the circumferential direction of the rotor core, and the permanent magnets are provided on a side of the rotor core close to the rotation axis.

9. The rotor assembly according to claim 8, characterized in that: The number of the yoke units is N, and the number of the permanent magnets is M, satisfying: M is an integer multiple of N.

10. The rotor assembly according to claim 9, wherein: The permanent magnet has a center line arranged along the radial direction of the rotor core, and the center line passes through the bending portion or the joint of two adjacent joint portions.

11. The motor is characterized in that include: stator assembly; The rotor assembly according to any one of claims 8 to 10, wherein the rotor assembly is wound around the outer circumference of the stator assembly.

12. A household appliance, characterized in that Comprising the motor as claimed in claim 11.

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