Rotor core, rotor assembly, motor and household appliance

Abstract

The utility model discloses a rotor core, a rotor assembly, a motor and a household electrical appliance, the rotor core comprises a first rotor punching sheet and a second rotor punching sheet, the first rotor punching sheet comprises a plurality of first punching sheet units arranged around a rotation axis at intervals, an outer magnetic bridge and an inner magnetic bridge, and two adjacent first punching sheet units are connected through the outer magnetic bridge or the inner magnetic bridge. The outer magnetic bridges are located at the ends, away from the rotating axis, of the first punching sheet units, the inner magnetic bridges are located at the ends, close to the rotating axis, of the first punching sheet units, and in each first rotor punching sheet, the number of the outer magnetic bridges and the number of the inner magnetic bridges are both at least one; the second rotor punching sheet comprises a plurality of second punching sheet units which are arranged around the rotating axis at intervals, every two adjacent second punching sheet units are disconnected, and the second rotor punching sheet and the first rotor punching sheet are arranged in a stacked mode in the direction of the rotating axis. The rotor core of the utility model can reduce magnetic flux leakage and effectively improve the efficiency of a motor.

Description

Technical Field

[0001] The utility model 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] Permanent magnet synchronous motors have high power density and torque density and are widely used in the field of household appliances. The performance of the motor is one of the important factors that determine the quality of the product. For the motor, the motor includes a rotor core, which is formed by axially stacking a plurality of rotor punchings. Among them, the rotor punching includes a plurality of fan-shaped parts, and the adjacent two fan-shaped parts are connected by an inner magnetic bridge and an outer magnetic bridge, and the permanent magnet is arranged between the adjacent fan-shaped parts. When this scheme is adopted, the leakage of the rotor core is more serious, resulting in a decrease in the efficiency of the permanent magnet motor. Some schemes reduce the leakage of magnetic flux by removing all the external magnetic bridges, but this scheme still has the problem of serious leakage of magnetic flux at the inner end of the permanent magnet; or if all the internal magnetic bridges are removed, there will be a serious problem of leakage of magnetic flux at the outer end of the permanent magnet. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides a rotor core that can reduce magnetic leakage and effectively improve the efficiency of the motor.

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

[0005] According to the rotor core of the first aspect of the utility model, there is a rotation axis, including a first rotor punching sheet, including a plurality of first punching sheet units arranged at intervals around the rotation axis, an external magnetic bridge, and an internal magnetic bridge. Two adjacent first punching sheet units are connected by the external magnetic bridge or the internal magnetic bridge. The external magnetic bridge is located at the end of the first punching sheet unit away from the rotation axis, and the internal magnetic bridge is located at the end of the first punching sheet unit close to the rotation axis. In each of the first rotor punching sheets, the number of the external magnetic bridges and the number of the internal magnetic bridges are both at least one; the second rotor punching sheet includes a plurality of second punching sheet units arranged at intervals around the rotation axis, and two adjacent second punching sheet units are disconnected. The second rotor punching sheet and the first rotor punching sheet are stacked along the direction of the rotation axis.

[0006] The rotor core according to the embodiment of the first aspect of the utility model has at least the following beneficial effects: the rotor core is composed of a first rotor punching sheet and a second rotor punching sheet, and the two adjacent first punching sheet units of the first rotor punching sheet are connected only by an external magnetic bridge or only by an internal magnetic bridge, and the number of external magnetic bridges and the number of internal magnetic bridges in each first rotor punching sheet are at least one, therefore, the number of external magnetic bridges and internal magnetic bridges of the first rotor punching sheet can be reduced at the same time, and the first rotor punching sheet can be made into a whole; at the same time, the two adjacent second punching sheet units of the second rotor punching sheet are disconnected, therefore, under the premise of ensuring the structural strength of the rotor core, the leakage magnetic field of the permanent magnet can be reduced, and the leakage magnetic field at the inner end and the outer end of the permanent magnet is less, thereby improving the efficiency of the motor.

[0007] According to some embodiments of the present invention, the number of the external magnetic bridges is equal to the number of the internal magnetic bridges.

[0008] According to some embodiments of the present invention, the outer magnetic bridges and the inner magnetic bridges are alternately arranged along the circumference of the rotor core.

[0009] According to some embodiments of the present invention, the plurality of outer magnetic bridges are arranged in sequence along the circumferential direction of the rotor core, and the plurality of inner magnetic bridges are arranged in sequence along the circumferential direction.

[0010] According to some embodiments of the utility model, the number of the external magnetic bridges and the number of the internal magnetic bridges are both at least two, at least two of the external magnetic bridges are arranged sequentially along the circumference of the rotor core, and at least two of the internal magnetic bridges are arranged sequentially along the circumference.

[0011] According to some embodiments of the present invention, along the radial direction of the rotor core, the minimum width of the external magnetic bridge is L1, and the maximum distance between the wall of the external magnetic bridge away from the rotation axis and the rotation axis is L2, satisfying: 0.01≤L1 / L2≤0.06.

[0012] According to some embodiments of the utility model, the second punching sheet unit includes a main body, and at least one of the second punching sheet units also includes a limiting portion, the limiting portion is connected to one end of the main body close to the rotation axis, and the limiting portion protrudes from the two side walls of the main body along the circumference of the rotor core.

[0013] According to some embodiments of the present invention, among any two adjacent second punching sheet units, one of the second punching sheet units includes the limiting portion.

[0014] According to some embodiments of the present invention, the minimum protruding height of the limiting portion relative to the wall of the main body is W1, and the minimum distance between the two relative walls of two adjacent main bodies along the circumferential direction of the rotor core is W2, satisfying: 0.05≤W1 / W2≤0.5.

[0015] According to some embodiments of the present invention, the maximum distance between the wall of the external magnetic bridge away from the rotation axis and the rotation axis is L2, and the minimum width of the limit portion along the radial direction of the rotor core is L3, satisfying: 0.01≤L3 / L2≤0.04.

[0016] According to the rotor assembly of the second aspect embodiment of the utility model, it includes the rotor core of the first aspect embodiment of the utility model, the rotor core includes a plurality of core units arranged around the rotation axis, and an installation groove is formed between two adjacent core units; a plurality of permanent magnets are respectively installed in the corresponding installation grooves.

[0017] According to the rotor assembly of the embodiment of the second aspect of the utility model, there are at least the following beneficial effects: since the rotor assembly adopts the above-mentioned rotor core, the rotor core is composed of a first rotor punching sheet and a second rotor punching sheet, and the two adjacent first punching sheet units of the first rotor punching sheet are connected only by an external magnetic bridge or only by an internal magnetic bridge, and the number of external magnetic bridges and the number of internal magnetic bridges in each first rotor punching sheet are at least one, therefore, the number of external magnetic bridges and internal magnetic bridges of the first rotor punching sheet can be reduced at the same time, and the first rotor punching sheet can be made into a whole; at the same time, the two adjacent second punching sheet units of the second rotor punching sheet are disconnected, therefore, under the premise of ensuring the structural strength of the rotor core, the leakage magnetic field of the permanent magnet can be reduced, and the leakage magnetic field at the inner end and the outer end of the permanent magnet is less, thereby improving the efficiency of the motor.

[0018] The motor according to the third aspect of the present invention comprises a stator assembly and a rotor assembly according to the second aspect of the present invention, wherein the stator assembly is arranged around the outer circumference of the rotor assembly.

[0019] The motor according to the embodiment of the third aspect of the utility model has at least the following beneficial effects: since the motor adopts the above-mentioned rotor assembly, the rotor core is composed of a first rotor punching sheet and a second rotor punching sheet, and the two adjacent first punching sheet units of the first rotor punching sheet are connected only by an external magnetic bridge or only by an internal magnetic bridge, and the number of external magnetic bridges and the number of internal magnetic bridges in each first rotor punching sheet are at least one, therefore, the number of external magnetic bridges and internal magnetic bridges of the first rotor punching sheet can be reduced at the same time, and the first rotor punching sheet can be made into a whole; at the same time, the two adjacent second punching sheet units of the second rotor punching sheet are disconnected, therefore, under the premise of ensuring the structural strength of the rotor core, the leakage magnetic field of the permanent magnet can be reduced, and the leakage magnetic field at the inner end and the outer end of the permanent magnet is less, thereby improving the efficiency of the motor.

[0020] The household appliance according to the fourth embodiment of the utility model includes the motor according to the third embodiment of the utility model.

[0021] The household appliance according to the embodiment of the fourth aspect of the utility model has at least the following beneficial effects: since the household appliance adopts the above-mentioned motor, the rotor core is composed of a first rotor punching sheet and a second rotor punching sheet, and the two adjacent first punching sheet units of the first rotor punching sheet are connected only by an external magnetic bridge or only by an internal magnetic bridge, and the number of external magnetic bridges and the number of internal magnetic bridges in each first rotor punching sheet are at least one, therefore, the number of external magnetic bridges and internal magnetic bridges of the first rotor punching sheet can be reduced at the same time, and the first rotor punching sheet can be made into a whole; at the same time, the two adjacent second punching sheet units of the second rotor punching sheet are disconnected, therefore, under the premise of ensuring the structural strength of the rotor core, the leakage magnetic field of the permanent magnet can be reduced, and the leakage magnetic field at the inner end and the outer end of the permanent magnet is less, thereby improving the efficiency of the motor and the household appliance.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0024] Figure 1 It is an axial schematic diagram of a first rotor punching sheet in one embodiment of the utility model;

[0025] Figure 2 yes Figure 1 A in the enlarged view;

[0026] Figure 3 is an axial schematic diagram of a first rotor punching sheet in another embodiment of the utility model;

[0027] Figure 4is an axial schematic diagram of a first rotor punching sheet in another embodiment of the utility model;

[0028] Figure 5 It is an axial schematic diagram of a second rotor punching sheet in one embodiment of the utility model;

[0029] Figure 6 is an axial schematic diagram of a second rotor punching sheet in another embodiment of the utility model;

[0030] Figure 7 yes Figure 6 The enlarged view of point B in the figure;

[0031] Figure 8 It is a schematic diagram of the magnetic force line distribution of the second rotor punching sheet in one embodiment of the utility model.

[0032] Reference numerals:

[0033] First rotor punching sheet 100; first punching sheet unit 110; outer magnetic bridge 120; first wall surface 121; second wall surface 122; inner magnetic bridge 130; first protrusion 140;

[0034] The second rotor punching sheet 200; the second punching sheet unit 210; the main body 211; the limiting portion 212; the third wall surface 2121; the fourth wall surface 2122; the fifth wall surface 2123; the second protrusion 220;

[0035] Mounting slot 300;

[0036] Axis of rotation Z. DETAILED DESCRIPTION

[0037] The embodiments of the present invention are described in detail below, and 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 only used to explain the present invention, and cannot be understood as limiting the present invention.

[0038] In the description of the present invention, it should be understood that descriptions involving orientation, 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, and 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, and therefore cannot be understood as a limitation on the present invention.

[0039] In the description of the present utility model, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0040] In the description of the present utility model, unless otherwise clearly defined, terms such as setting, installing, connecting, assembling, and matching should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present utility model based on the specific content of the technical solution.

[0041] Reference Figures 1 to 8 As shown, the first embodiment of the utility model provides a rotor core as a part of a rotor assembly, which is applied to a motor of a household appliance, wherein the motor is usually a permanent magnet motor, and the household appliance may be a fan, an air conditioner, a refrigerator, a washing machine, etc. For example, the motor including the rotor core is applied to a compressor of an air conditioner or a refrigerator.

[0042] It can be understood that the rotor core has a rotation axis Z, which is the central axis of the rotor core. The direction along the rotation axis Z is defined as the axial direction of the rotor core, the direction around the rotation axis Z is defined as the circumferential direction of the rotor core, and the direction perpendicular to the rotation axis Z from the rotation axis Z to the outer peripheral wall of the rotor core and the reverse direction is defined as the radial direction of the rotor core.

[0043] It can be understood that the rotor core is composed of a first rotor punching 100 and a second rotor punching 200, and the number of the first rotor punching 100 and the second rotor punching 200 is multiple, and the multiple first rotor punchings 100 and the multiple second rotor punchings 200 are stacked along the direction (i.e., axial direction) of the rotation axis Z. It is easy to understand that the multiple first rotor punchings 100 and the multiple second rotor punchings 200 can be stacked in any order along the axial direction.

[0044] Reference Figure 1 As shown, it can be understood that the first rotor punching sheet 100 includes a plurality of first punching sheet units 110, an outer magnetic bridge 120 and an inner magnetic bridge 130. For example, the number of the first punching sheet units 110 is ten, and the plurality of first punching sheet units 110 are arranged at intervals around the rotation axis Z (i.e., the circumferential direction of the rotor core). The first punching sheet units 110 are roughly fan-shaped, and the small end of the fan-shaped structure is closer to the rotation axis Z than the large end.

[0045] Reference Figure 1 , Figure 3 and Figure 4As shown, it can be understood that two adjacent first punching sheet units 110 are connected by an external magnetic bridge 120 or an internal magnetic bridge 130, and the external magnetic bridge 120 is located between the outer ends of the two adjacent first punching sheet units 110 of the part, and the internal magnetic bridge 130 is located between the inner ends of the two adjacent first punching sheet units 110 of the part, and each first rotor punching sheet 100 includes at least one external magnetic bridge 120 and at least one internal magnetic bridge 130, so that the entire first rotor punching sheet 100 is connected as a whole. It is easy to understand that the outer end here is the end of the first punching sheet unit 110 away from the rotation axis Z, and the inner end is the end of the first punching sheet unit 110 close to the rotation axis Z. In this way, the number of the external magnetic bridge 120 and the internal magnetic bridge 130 of the first rotor punching sheet 100 can be reduced at the same time.

[0046] Reference Figure 1 As shown, it can be understood that in this embodiment, specifically, in each first rotor punching sheet 100, the number of the outer magnetic bridges 120 is equal to the number of the inner magnetic bridges 130, and the outer magnetic bridges 120 and the inner magnetic bridges 130 are alternately arranged along the circumference of the rotor core. That is to say, among the multiple first punching sheet units 110 arranged in sequence along the circumference of the rotor core, the first first punching sheet unit 110 is connected to the second first punching sheet unit 110 through the outer magnetic bridge 120, the second first punching sheet unit 110 is connected to the third first punching sheet unit 110 through the inner magnetic bridge 130, the third first punching sheet unit 110 is connected to the fourth first punching sheet unit 110 through the outer magnetic bridge 120, and so on, so that the multiple first punching sheet units 110 are connected into a whole. In this way, the overall structure of the first rotor punching sheet 100 is more balanced, which is conducive to ensuring the structural strength.

[0047] Reference Figure 3 As shown, it can be understood that in other embodiments, the number of the external magnetic bridges 120 of each first rotor sheet 100 is equal to the number of the internal magnetic bridges 130, and the multiple external magnetic bridges 120 are arranged in sequence along the circumference of the rotor core, and the multiple internal magnetic bridges 130 are arranged in sequence along the circumference of the rotor core. In other words, the number of first sheet units 110 is defined as N, and along the circumference of the rotor core, consecutive (N / 2)+1 first sheet units 110 are connected by external magnetic bridges 120, and then (N / 2)+1 first sheet units 110 are connected by internal magnetic bridges 130, so that multiple first sheet units 110 are connected into a whole. The overall structural strength of the first rotor sheet 100 is also relatively high.

[0048] Reference Figure 4As shown, it can be understood that in other embodiments, the number of the external magnetic bridges 120 and the number of the internal magnetic bridges 130 of each first rotor punching sheet 100 are both at least two, and the number of the external magnetic bridges 120 and the number of the internal magnetic bridges 130 are not equal, at least two external magnetic bridges 120 are arranged in sequence along the circumference of the rotor core, and at least two internal magnetic bridges 130 are arranged in sequence along the circumference of the rotor core. For example, four consecutive first punching sheet units 110 are connected by an external magnetic bridge 120, and then three consecutive first punching sheet units 110 are connected by an internal magnetic bridge 130, and then four consecutive first punching sheet units 110 are connected by an external magnetic bridge 120, and so on, so that multiple first punching sheet units 110 are connected into a whole, which can also make the first rotor punching sheet 100 have a higher structural strength.

[0049] Of course, the number of internal magnetic bridges 130 of the first rotor punching sheet 100 can be only two. The two internal magnetic bridges 130 are connected between three consecutive first punching sheet units 110, and the remaining first punching sheet units 110 are connected through external magnetic bridges 120, which can also connect multiple first punching sheet units 110 into a whole.

[0050] It can be understood that in other embodiments, the outer magnetic bridge 120 and the inner magnetic bridge 130 of the first rotor punching sheet 100 can be arranged in other ways, and the number of the outer magnetic bridge 120 and the inner magnetic bridge 130 can be other. It is only necessary to ensure that the first rotor punching sheet 100 includes at least one outer magnetic bridge 120 and at least one inner magnetic bridge 130, and that two adjacent first punching sheet units 110 are connected only by the outer magnetic bridge 120 or the inner magnetic bridge 130, and that multiple first punching sheet units 110 can be connected into a whole, which will not be elaborated here.

[0051] Reference Figure 5 As shown, it can be understood that the second rotor punching sheet 200 includes a plurality of second punching sheet units 210, the number of the second punching sheet units 210 of each second rotor punching sheet 200 is equal to the number of the first punching sheet units 110 of each first rotor punching sheet 100, and the shape of the second punching sheet unit 210 is substantially the same as the shape of the first punching sheet unit 110. The plurality of second punching sheet units 210 are arranged at intervals around the rotation axis Z (i.e., the circumferential direction of the rotor core), and the two adjacent second punching sheet units 210 are disconnected, that is, each second punching sheet unit 210 is an independent individual, and there is no magnetic bridge connecting the two adjacent second punching sheet units 210. The shape of each second punching sheet unit 210 can be the same, so the types of molds can be reduced, the blanking process is convenient, and it is beneficial to improve production efficiency and reduce production costs.

[0052] It can be understood that after the plurality of first rotor sheets 100 and the plurality of second rotor sheets 200 of any of the above embodiments are stacked in the axial direction, the plurality of first sheet units 110 on each first rotor sheet 100 and the plurality of second sheet units 210 on each second rotor sheet 200 are arranged one by one in the axial direction, and the plurality of first sheet units 110 and the plurality of second sheet units 210 arranged in the axial direction in correspondence form a core unit. That is, the rotor core includes a plurality of core units, the number of which is equal to the number of the first sheet units 110 on each first rotor sheet 100, and the plurality of core units are arranged at intervals around the rotation axis Z, and an installation groove 300 is defined between two adjacent core units, that is, the installation groove 300 is located between two first sheet units 110 adjacent to each other in the circumferential direction, and is also located between two second sheet units 210 adjacent to each other in the circumferential direction, and the installation groove 300 axially penetrates the two axial end faces of the rotor core.

[0053] It is understandable that the rotor assembly also includes a plurality of permanent magnets, the number of which is equal to the number of the mounting slots 300, or the number of which is an integral multiple of the number of the mounting slots 300. A plurality of permanent magnets are installed in the corresponding mounting slots 300, that is, a permanent magnet is installed in each mounting slot 300, or a plurality of permanent magnets are installed in each mounting slot 300. The two radial walls of the permanent magnet along the rotor core are respectively against the outer magnetic bridge 120 and the inner magnetic bridge 130, so that the outer magnetic bridge 120 and the inner magnetic bridge 130 can be used to limit the permanent magnet to ensure that the permanent magnet is firmly installed, avoid the risk of the permanent magnet loosening or falling off during the rotation of the rotor assembly, and make the overall structure of the rotor assembly stable. Generally speaking, the rotor assembly also includes a plastic coating, which covers the two axial end faces of the rotor core, and the plastic coating fills the gap between the permanent magnet and the rotor core, thereby further enhancing the overall stability of the rotor assembly.

[0054] It can be understood that since the magnetic lines of force of the permanent magnet's magnetic field can form a closed loop through the magnetic bridge between two adjacent core units, causing magnetic leakage, this part of the magnetic lines of force does not pass through the stator assembly of the motor, which will lead to a decrease in the utilization rate of the permanent magnet's magnetic field and a decrease in the efficiency of the motor.

[0055] For this purpose, refer to Figure 1 and Figure 5As shown, it can be understood that in the rotor core, by connecting two first punching sheet units 110 adjacent to each other in the circumferential direction only through the outer magnetic bridge 120 or the inner magnetic bridge 130, and each first rotor punching sheet 100 includes at least one outer magnetic bridge 120 and at least one inner magnetic bridge 130, the number of the outer magnetic bridge 120 and the inner magnetic bridge 130 of the first rotor punching sheet 100 can be reduced at the same time, and the two second punching sheet units 210 adjacent to each other in the circumferential direction are disconnected (i.e., there is no connecting magnetic bridge), so that the number of magnetic bridges can be reduced, that is, the volume of the connecting structure (i.e., the magnetic bridge) between the two adjacent core units is reduced, so that the magnetic flux of the connecting structure between the two adjacent core units is easily saturated, thereby reducing the leakage magnetic flux of the permanent magnet, thereby improving the efficiency of the motor. It is easy to understand that since the number of magnetic bridges is reduced, the material consumption of the rotor core is also reduced, which is conducive to reducing the manufacturing cost. In addition, since the number of external magnetic bridges 120 and internal magnetic bridges 130 of the first rotor punching sheet 100 can be reduced at the same time, the volume of the connection structure between the outer end and the inner end of two adjacent core units is reduced, which can reduce the leakage flux at the inner end and the outer end of the permanent magnet, which is beneficial to improving the efficiency of the motor.

[0056] Reference Figure 8 As shown, it can be understood that the figure shows the magnetic field line distribution diagram of the second rotor punching sheet 200 in the rotor assembly. It can be seen from the figure that there are no magnetic field lines between two adjacent second punching sheet units 210, that is, there is no leakage magnetic flux, thereby effectively reducing the overall leakage magnetic flux.

[0057] Referring to Table 1, it can be understood that, under the premise of a rotation speed of 1800 rpm and a torque of 1.066 Nm, the efficiency of the motor of the present embodiment is 82%, and the efficiency of the motor of the prior art is 81%. Compared with the prior art, the efficiency of the motor of the present embodiment is improved by 1%.

[0058] Table 1 Motor performance comparison

[0059] This program Existing technical solutions Speed ​​(rpm) 1800 1800 Torque(Nm) 1.066 1.066 efficiency(%) 82 81

[0060] Reference Figure 1 and Figure 5As shown, it can be understood that, in order to further improve the installation stability of the permanent magnet, for the first rotor punching sheet 100, in the two adjacent first punching sheet units 110 connected by the internal magnetic bridge 130, the two first punching sheet units 110 are further provided with first protrusions 140 on opposite sides, the two first protrusions 140 are located at the outer end of the first punching sheet unit 110 and protrude from the two wall surfaces of the mounting groove 300 arranged oppositely along the circumference of the rotor core, and the two first protrusions 140 are disconnected. Similarly, for the second rotor punching sheet 200, the two adjacent second punching sheet units 210 are further provided with second protrusions 220 on opposite sides, the two second protrusions 220 are located at the outer end of the second punching sheet unit 210 and protrude from the two wall surfaces of the mounting groove 300 arranged oppositely along the circumference of the rotor core, the two second protrusions 220 are disconnected, and part of the second protrusions 220 are arranged correspondingly to the first protrusions 140 along the axial direction. Therefore, the first protrusion 140 and the second protrusion 220 can contact the wall surface (i.e., the outer wall surface) on the permanent magnet away from the rotation axis Z, thereby limiting the permanent magnet and further improving the installation stability of the permanent magnet. It is easy to understand that since the two adjacent first protrusions 140 located in the installation groove 300 are disconnected and the two adjacent second protrusions 220 are also disconnected, the first protrusion 140 and the second protrusion 220 will not cause permanent magnet leakage, effectively ensuring the efficiency of the motor.

[0061] Reference Figure 6 As shown, it can be understood that in other embodiments, the second punching sheet unit 210 includes a main body 211, and the main body 211 is fan-shaped. In each second rotor punching sheet 200, at least one second punching sheet unit 210 also includes a limiting portion 212. Specifically, the limiting portion 212 is connected to one end of the main body 211 close to the rotation axis Z, and the limiting portion 212 protrudes from the two side walls of the main body 211 along the circumferential direction of the rotor core. For example, one, two or three second punching sheet units 210 in each second rotor punching sheet 200 include a limiting portion 212, and the other second punching sheet units 210 do not have a limiting portion 212; or all the second punching sheet units 210 in each second rotor punching sheet 200 include a limiting portion 212. Therefore, the protruding parts at both ends of each limiting portion 212 along the circumferential direction can respectively contact the wall surface (i.e., the inner wall surface) on the two adjacent permanent magnets close to the rotation axis Z, thereby further improving the installation stability of the permanent magnet, and the limiting portion 212 will not connect the two adjacent second punching unit 210, so that the limiting portion 212 will not cause magnetic leakage, effectively ensuring the efficiency of the motor.

[0062] Reference Figure 6As shown, it can be understood that, in any two adjacent second punching sheet units 210, one of the second punching sheet units 210 includes a limiting portion 212. That is, in each second rotor punching sheet 200, the second punching sheet units 210 including the limiting portion 212 and the second punching sheet units 210 without the limiting portion 212 are alternately arranged in the circumferential direction of the rotor core. It can also be understood that in each second rotor punching sheet 200, the number of limiting portions 212 is half of the number of second punching sheet units 210, and a plurality of limiting portions 212 are evenly distributed along the circumferential direction of the rotor core. At this time, half of the second punching sheet units 210 have the same shape, and the other half of the second punching sheet units 210 have the same shape, and the number of limiting portions 212 is only half of the number of second punching sheet units 210. Therefore, only half of the second punching sheet units 210 are provided with the limiting portion 212, so that the inner wall surface of each permanent magnet can be limited, which can not only ensure the installation stability of the permanent magnet, but also reduce the material consumption, thereby reducing the production cost.

[0063] It is understandable that in the rotor core, the second rotor sheet 200 may be any one of the above embodiments; or the second rotor sheet 200 may include the above two embodiments, wherein only one second rotor sheet 200 including the limiting portion 212 may be provided, or only the second rotor sheets 200 located at both ends of the rotor core along the axial direction may include the limiting portion 212, or only one or more second rotor sheets 200 located in the middle position of the rotor core along the axial direction may include the limiting portion 212, or the middle second rotor sheet 200 among every three second rotor sheets 200 may include the limiting portion 212. No further description will be given here.

[0064] Reference Figure 2 As shown, it can be understood that, along the radial direction of the rotor core, the minimum width of the external magnetic bridge 120 is L1. The two radially opposite walls of the external magnetic bridge 120 along the rotor core are defined as the first wall 121 and the second wall 122, wherein the first wall 121 is located on the side of the external magnetic bridge 120 away from the rotation axis Z, and the second wall 122 is located on the side of the external magnetic bridge 120 close to the rotation axis Z. Therefore, the minimum width L1 of the external magnetic bridge 120 is the minimum distance between the first wall 121 and the second wall 122, and the vernier caliper can be used to directly measure the position where the distance between the first wall 121 and the second wall 122 is the smallest.

[0065] Reference Figure 1 and Figure 2As shown, it can be understood that the maximum distance between the wall of the outer magnetic bridge 120 away from the rotation axis Z and the rotation axis Z is defined as L2, that is, the maximum distance between the first wall 121 and the rotation axis Z is L2. It is easy to understand that L2 is close to half of the maximum outer diameter of the rotor core. L1 and L2 satisfy: 0.01≤L1 / L2≤0.06. Generally speaking, the maximum outer diameter of the rotor core is basically determined due to the overall size of the motor. If L1 / L2<0.01, the minimum width of the outer magnetic bridge 120 will be too small, the processing difficulty will be large, and the connection strength will be low, resulting in a decrease in the overall structural strength of the first rotor punching sheet 100, affecting the structural stability of the rotor core. At the same time, the outer magnetic bridge 120 is easy to deform or break, and the limiting effect on the permanent magnet is poor, which is easy to cause the permanent magnet to loosen or even fall off; if L1 / L2>0.06, the minimum width of the outer magnetic bridge 120 is too large, the leakage magnetic flux of the permanent magnet increases, and the efficiency of the motor is affected. Therefore, by making 0.01≤L1 / L2≤0.06, for example, the value of L1 / L2 is 0.01, 0.02, 0.03, 0.04, 0.05 or 0.06, etc., under the premise of ensuring the stability of the rotor core and the installation stability of the permanent magnet, the leakage magnetic field of the permanent magnet can be effectively reduced, the efficiency of the motor can be improved, and it is beneficial to reduce the processing difficulty of the first rotor punching sheet 100.

[0066] It is understandable that the minimum width of the inner magnetic bridge 130 along the radial direction is equal to the minimum width L1 of the outer magnetic bridge 120, which will not be described in detail here. It is easy to understand that the minimum width L1 of the outer magnetic bridge 120 and the minimum width of the inner magnetic bridge 130 both satisfy: 0.35mm≤L1≤1.5mm, for example, L1=0.5mm or L1=1mm, etc.

[0067] Reference Figure 1 and Figure 7As shown, it can be understood that the minimum width of the limiting portion 212 along the radial direction of the rotor core is L3. The protruding portion of the limiting portion 212 is defined to have a third wall 2121 and a fourth wall 2122 that are opposite to each other along the radial direction of the rotor core, and the minimum distance between the third wall 2121 and the fourth wall 2122 is L3. L2 and L3 satisfy: 0.01≤L3 / L2≤0.04. Similarly, when the maximum outer diameter of the rotor core is basically determined, if L3 / L2<0.01, the minimum width of the limiting portion 212 will be too small, the processing difficulty will be large, and the structural strength will be low, it will be easy to deform, the limiting effect on the permanent magnet will be poor, and the permanent magnet will be easily loosened, affecting the installation stability of the permanent magnet; since the limiting portion 212 only provides auxiliary limiting for the permanent magnet, it is not necessary to set it too large. If L3 / L2>0.04, the minimum width of the limiting portion 212 is too large, resulting in material waste and high manufacturing cost. Therefore, by making 0.01≤L3 / L2≤0.04, for example, the value of L3 / L2 is 0.01, 0.02, 0.03 or 0.04, etc., the manufacturing cost can be effectively reduced while ensuring the installation stability of the permanent magnet, and it is conducive to reducing the difficulty of processing. It is easy to understand that the minimum width L3 of the limit portion 212 satisfies: 0.5mm≤L3≤1mm, for example, L3=0.7mm or L3=0.9mm, etc.

[0068] Reference Figure 6 and Figure 7As shown, it can be understood that the minimum protruding height of the limiting portion 212 relative to the wall of the main body 211 is W1, and it is defined that the end of the limiting portion 212 away from the main body 211 has a fifth wall 2123, and W1 is the minimum distance between the fifth wall 2123 and the wall of the main body 211 connected to the limiting portion 212 that faces the mounting groove 300 and faces the same direction as the fifth wall 2123. The minimum distance between the two opposite walls of two adjacent main bodies 211 along the circumference of the rotor core is W2, and W2 is the minimum distance between the two walls of the mounting groove 300 that are arranged oppositely along the circumference of the rotor core. W1 and W2 satisfy: 0.05≤W1 / W2≤0.5. Generally speaking, according to the magnet usage of the motor, the width of the permanent magnet along the circumference of the rotor core is basically determined, that is, W2 is basically determined. If W1 / W2<0.05, the minimum protruding height of the limiting portion 212 will be too small, the processing difficulty is large, and the structural strength is low, it is easy to deform, the limiting effect on the permanent magnet is poor, and it is easy to cause the permanent magnet to loosen, affecting the installation stability of the permanent magnet; since the limiting portion 212 only provides auxiliary limiting for the permanent magnet, it is not necessary to set it too large. If W1 / W2>0.5, the minimum protruding height of the limiting portion 212 is too large, resulting in material waste and high manufacturing cost. Therefore, 0.05≤W1 / W2≤0.5, for example, the value of W1 / W2 is 0.1, 0.2, 0.3 or 0.5, etc., under the premise of ensuring the installation stability of the permanent magnet, the manufacturing cost can be effectively reduced, and it is conducive to reducing the difficulty of processing. It is easy to understand that the minimum protruding height W1 of the limiting portion 212 satisfies: 0.4mm≤W1≤1.8mm at the same time, for example, W1=0.5mm or W1=1mm, etc.

[0069] The rotor assembly of the second embodiment of the utility model includes the rotor core and a plurality of permanent magnets of the first embodiment of the utility model, which will not be described in detail here.

[0070] Since the rotor assembly adopts all the technical solutions of the rotor core of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment.

[0071] The motor of the third embodiment of the utility model comprises a stator assembly and a rotor assembly of the second embodiment of the utility model, wherein the stator assembly is arranged around the outer circumference of the rotor assembly. The motor can be applied to compressors, fans, washing machines, etc. of air conditioners or refrigerators.

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

[0073] The household appliance of the fourth embodiment of the utility model comprises the motor of the third embodiment of the utility model, and the household appliance may be a fan, an air conditioner, a refrigerator or a washing machine.

[0074] 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 by the technical solutions of the above embodiment.

[0075] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A rotor core having a rotation axis, characterized in that: include: The first rotor punching sheet comprises a plurality of first punching sheet units arranged at intervals around the rotation axis, an external magnetic bridge, and an internal magnetic bridge. Two adjacent first punching sheet units are connected by the external magnetic bridge or the internal magnetic bridge. The external magnetic bridge is located at an end of the first punching sheet unit away from the rotation axis, and the internal magnetic bridge is located at an end of the first punching sheet unit close to the rotation axis. In each of the first rotor punching sheets, the number of the external magnetic bridges and the number of the internal magnetic bridges are both at least one. The second rotor punching sheet comprises a plurality of second punching sheet units arranged at intervals around the rotation axis, two adjacent second punching sheet units are disconnected, and the second rotor punching sheet and the first rotor punching sheet are stacked and arranged along the direction of the rotation axis.

2. The rotor core according to claim 1, characterized in that: The number of the outer magnetic bridges is equal to the number of the inner magnetic bridges.

3. The rotor core according to claim 2, characterized in that: The outer magnetic bridges and the inner magnetic bridges are alternately arranged along the circumferential direction of the rotor core.

4. The rotor core according to claim 2, characterized in that: The plurality of outer magnetic bridges are arranged in sequence along the circumferential direction of the rotor core, and the plurality of inner magnetic bridges are arranged in sequence along the circumferential direction.

5. The rotor core according to claim 1, characterized in that: The number of the outer magnetic bridges and the number of the inner magnetic bridges are both at least two, at least two of the outer magnetic bridges are arranged in sequence along the circumferential direction of the rotor core, and at least two of the inner magnetic bridges are arranged in sequence along the circumferential direction.

6. The rotor core according to any one of claims 1 to 5, characterized in that: Along the radial direction of the rotor core, the minimum width of the external magnetic bridge is L1, and the maximum distance between the wall of the external magnetic bridge away from the rotation axis and the rotation axis is L2, satisfying: 0.01≤L1 / L2≤0.

06.

7. The rotor core according to claim 1, characterized in that: The second punching sheet unit includes a main body, and at least one of the second punching sheet units also includes a limiting portion, which is connected to one end of the main body close to the rotation axis, and the limiting portion protrudes from the two side walls of the main body along the circumference of the rotor core.

8. The rotor core according to claim 7, characterized in that: Among any two adjacent second punching sheet units, one of the second punching sheet units includes the limiting portion.

9. The rotor core according to claim 7 or 8, characterized in that: The minimum protruding height of the limiting portion relative to the wall surface of the main body is W1, and the minimum distance between two adjacent main body portions along the circumferential direction of the rotor core relative to the wall surface is W2, satisfying: 0.05≤W1 / W2≤0.

5.

10. The rotor core according to claim 7 or 8, characterized in that: The maximum distance between the wall of the outer magnetic bridge away from the rotation axis and the rotation axis is L2, and the minimum width of the limiting portion along the radial direction of the rotor core is L3, which satisfies: 0.01≤L3 / L2≤0.

04.

11. A rotor assembly, characterized in that: include: The rotor core according to any one of claims 1 to 10, comprising a plurality of core units arranged around the rotation axis, and a mounting groove is formed between two adjacent core units; A plurality of permanent magnets are respectively installed in the corresponding installation slots.

12. A motor, characterized in that The invention comprises a stator assembly and the rotor assembly according to claim 11, wherein the stator assembly is arranged around the outer circumference of the rotor assembly.

13. A household appliance, characterized in that Including the motor as claimed in claim 12.

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