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 and outer magnetic bridges, the first punching sheet units are arranged around a rotation axis at intervals, any two adjacent first punching sheet units are connected through one outer magnetic bridge, and the second punching sheet units are connected through one outer magnetic bridge. The outer magnetic bridge is located at one end of the first punching unit away from the rotation axis; 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, improve the efficiency of the motor, effectively improve the stability of the permanent magnets, and improve the stability of high-speed operation of the motor.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, and particularly relates 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 determining the quality of the product. For a motor, the motor includes a rotor core, which is formed by axially laminating a plurality of rotor punching sheets. Among them, the rotor punching sheet includes a plurality of fan-shaped parts, and adjacent two fan-shaped parts are connected by an inner magnetic bridge and an outer magnetic bridge, and a permanent magnet is arranged between adjacent fan-shaped parts. When adopting this scheme, the magnetic leakage of the rotor core is relatively serious, resulting in a reduction in the efficiency of the permanent magnet motor. Some schemes reduce magnetic leakage by making the outer end of the permanent magnet installation groove of the rotor core a full opening, however, this will cause the structural strength of the rotor core to deteriorate. Summary of the Utility Model

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. For this purpose, the utility model provides a rotor core, which can reduce magnetic leakage, improve the efficiency of the motor, and ensure the structural strength of the rotor core.

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

[0005] The rotor core according to the first aspect embodiment of the utility model has a rotation axis and includes a first rotor punching sheet, which includes a plurality of first punching units and an outer magnetic bridge arranged at intervals around the rotation axis. Any two adjacent first punching units are connected by one outer magnetic bridge, and the outer magnetic bridge is located at one end of the first punching unit away from the rotation axis; a second rotor punching sheet, which includes a plurality of second punching units arranged at intervals around the rotation axis, and there is a break between two adjacent second punching units. The second rotor punching sheet and the first rotor punching sheet are laminated along the direction of the rotation axis.

[0006] The rotor core according to the first aspect embodiment 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. Among them, there is a break between two adjacent second punching units of the second rotor punching sheet, which can effectively reduce magnetic leakage, thereby improving the efficiency of the motor; at the same time, two adjacent first punching units of the first rotor punching sheet are connected by an outer magnetic bridge, making the first rotor punching sheet a whole, with high structural strength, which is beneficial to ensuring the overall structural strength of the rotor core.

[0007] According to some embodiments of the present invention, the first rotor punching sheet further includes an internal magnetic bridge, and any two adjacent first punching sheet units are further connected via an internal magnetic bridge, and the internal magnetic bridge is located at one end of the first punching sheet unit close to the rotation axis.

[0008] According to some embodiments of the present invention, a plurality of the inner magnetic bridges are connected in sequence and have an inner contour that is a polygon.

[0009] According to some embodiments of the present invention, each of the second punching sheet units has the same outer contour.

[0010] 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 connected to one end of the main body close to the rotation axis, and the limiting portion protrudes from two wall surfaces of the main body that are opposite to each other along the circumferential direction of the rotor core.

[0011] According to some embodiments of the present invention, in each of the second rotor punching sheets, the number of the limiting portions is half the number of the second punching sheet units, and the plurality of limiting portions are evenly distributed along the circumferential direction of the rotor core.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] The rotor assembly according to the second aspect embodiment of the present utility model has at least the following beneficial effects: Since the above-mentioned rotor core is adopted in the rotor assembly, the rotor core is composed of a first rotor punching sheet and a second rotor punching sheet. Among them, the adjacent two second punching units of the second rotor punching sheet are disconnected, which can effectively reduce magnetic leakage, thereby improving the efficiency of the motor; at the same time, the adjacent two first punching units of the first rotor punching sheet are connected by an external magnetic bridge, making the first rotor punching sheet a whole, with high structural strength, which is beneficial to ensuring the overall structural strength of the rotor core.

[0017] The motor according to the third aspect embodiment of the present utility model includes a stator assembly and the rotor assembly according to the second aspect embodiment of the present utility model, and the stator assembly is arranged around the outer periphery of the rotor assembly.

[0018] The motor according to the third aspect embodiment of the present utility model has at least the following beneficial effects: Since the above-mentioned rotor assembly is adopted in the motor, the rotor core is composed of a first rotor punching sheet and a second rotor punching sheet. Among them, the adjacent two second punching units of the second rotor punching sheet are disconnected, which can effectively reduce magnetic leakage, thereby improving the efficiency of the motor; at the same time, the adjacent two first punching units of the first rotor punching sheet are connected by an external magnetic bridge, making the first rotor punching sheet a whole, with high structural strength, which is beneficial to ensuring the overall structural strength of the rotor core.

[0019] The household appliance according to the fourth aspect embodiment of the present utility model includes the motor according to the third aspect embodiment of the present utility model.

[0020] The household appliance according to the fourth aspect embodiment of the present utility model has at least the following beneficial effects: Since the above-mentioned motor is adopted in the household appliance, the rotor core is composed of a first rotor punching sheet and a second rotor punching sheet. Among them, the adjacent two second punching units of the second rotor punching sheet are disconnected, which can effectively reduce magnetic leakage, thereby improving the efficiency of the motor; at the same time, the adjacent two first punching units of the first rotor punching sheet are connected by an external magnetic bridge, making the first rotor punching sheet a whole, with high structural strength, which is beneficial to ensuring the overall structural strength of the rotor core.

[0021] The additional aspects and advantages of the present utility model will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following further describes the present utility model in conjunction with the drawings and embodiments, where:

[0023] Figure 1 is the axial schematic diagram of the first rotor punching sheet in an embodiment of the present utility model;

[0024] Figure 2 isFigure 1 Enlarged view of part A in

[0025] Figure 3 Axial schematic diagram of the first rotor punching sheet in another embodiment of the present utility model;

[0026] Figure 4 Axial schematic diagram of the second rotor punching sheet in an embodiment of the present utility model;

[0027] Figure 5 Axial schematic diagram of the second rotor punching sheet in another embodiment of the present utility model;

[0028] Figure 6 is Figure 5 Enlarged view of part B in

[0029] Figure 7 Magnetic line distribution schematic diagram of the second rotor punching sheet in an embodiment of the present utility model.

[0030] Reference numerals:

[0031] 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;

[0032] Second rotor punching sheet 200; Second punching sheet unit 210; Main body part 211; Limiting part 212; Third wall surface 2121; Fourth wall surface 2122; Fifth wall surface 2123; Protrusion 220;

[0033] Mounting groove 300;

[0034] Rotation axis Z. Detailed implementation manners

[0035] The embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present utility model and should not be construed as a limitation of the present utility model.

[0036] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as up, down, front, back, left, right, etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model.

[0037] In the description of the present utility model, the meaning of "several" is one or more, the meaning of "multiple" is more than two, and understandings such as "greater than", "less than", "exceeding", etc. do not include the corresponding number, while understandings such as "above", "below", "within", etc. include the corresponding number. If there is a description of "first" and "second", it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0038] In the description of the present utility model, unless otherwise clearly defined, words such as "set", "installed", "connected", "assembled", "matched", etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present utility model in combination with the specific content of the technical solution.

[0039] Refer to Figures 1 to 7 As shown, an embodiment of the first aspect of the present utility model provides a rotor core, which is a part of the rotor assembly and is applied to the motor of household appliances. Among them, the motor is usually a permanent magnet motor, and the household appliances can be a fan, an air conditioner, a refrigerator, a washing machine, etc. For example, the motor including the above rotor core is applied to the compressor of an air conditioner or a refrigerator.

[0040] It can be understood that the rotor core has a rotation axis, and the rotation axis is the central axis of the rotor core. Define the direction along the rotation axis as the axial direction of the rotor core, the direction around the rotation axis as the circumferential direction of the rotor core, and the direction from the rotation axis perpendicular to the rotation axis to the outer peripheral wall of the rotor core and its reverse direction as the radial direction of the rotor core.

[0041] It can be understood that the rotor core is composed of a first rotor punching sheet 100 and a second rotor punching sheet 200. The number of the first rotor punching sheet 100 and the second rotor punching sheet 200 is multiple. The multiple first rotor punching sheets 100 and the multiple second rotor punching sheets 200 are stacked along the direction of the rotation axis (i.e., the axial direction). It is easy to understand that the multiple first rotor punching sheets 100 and the multiple second rotor punching sheets 200 can be stacked along the axial direction in any order.

[0042] Refer to Figure 1 As shown, it can be understood that the first rotor punching sheet 100 includes multiple first punching units 110 and multiple outer magnetic bridges 120. For example, in this embodiment, the number of the first punching units 110 is ten. The multiple first punching units 110 are arranged at intervals around the rotation axis (i.e., the circumferential direction of the rotor core). The first punching unit 110 is generally in a fan-shaped structure, and the large end of the fan-shaped structure is farther from the rotation axis than the small end.

[0043] Refer to Figure 1As shown, it can be understood that any two adjacent first punching sheet units 110 are connected by an outer magnetic bridge 120, and the outer magnetic bridge 120 is located between the outer ends of the two adjacent first punching sheet units 110. That is to say, the outer ends of all the first punching sheet units 110 of the first rotor punching sheet 100 are connected into a whole by the outer magnetic bridge 120, while the inner ends of two adjacent first punching sheet units 110 are not connected. In each first rotor punching sheet 100, the number of outer magnetic bridges 120 is equal to the number of first punching sheet units 110. In this way, the overall structural strength of the first rotor punching sheet 100 is relatively high, and the structural stability is relatively good, which is beneficial to improving the overall structural strength of the rotor core. And since the inner ends of two adjacent first punching sheet units 110 are not connected, the magnetic leakage at the position close to the inner end can be effectively reduced. It is easy to understand that the outer end here is the end of the first punching sheet unit 110 far from the rotation axis, and the inner end is the end of the first punching sheet unit 110 close to the rotation axis.

[0044] Referring to Figure 3 As shown, it can be understood that in some other embodiments, the first rotor punching sheet 100 includes a plurality of first punching sheet units 110, a plurality of outer magnetic bridges 120 and a plurality of inner magnetic bridges 130. The structures and layouts of the plurality of first punching sheet units 110 can refer to the above description and will not be elaborated here. Any two adjacent first punching sheet units 110 are connected by an outer magnetic bridge 120 and a first inner magnetic bridge 130. Among them, the outer magnetic bridge 120 is located between the outer ends of the two adjacent first punching sheet units 110, and the inner magnetic bridge 130 is located between the inner ends of the two adjacent first punching sheet units 110. That is to say, the outer ends of all the first punching sheet units 110 of the first rotor punching sheet 100 are connected into a whole by the outer magnetic bridge 120, and the inner ends of all the first punching sheet units 110 are also connected by the inner magnetic bridge 130. In each first rotor punching sheet 100, the number of outer magnetic bridges 120 and the number of inner magnetic bridges 130 are both equal to the number of first punching sheet units 110. In this way, the overall structural strength of the first rotor punching sheet 100 is higher, the structural stability is better, and the overall structural strength of the rotor core is higher, which is beneficial to ensuring the structural stability of the rotor core.

[0045] Referring to Figure 4As 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 outer shape of the second punching sheet unit 210 is substantially the same as that of the first punching sheet unit 110. The plurality of second punching sheet units 210 are arranged at intervals around the rotation axis (i.e., the circumferential direction of the rotor core), and there is a break between two adjacent second punching sheet units 210. That is to say, each second punching sheet unit 210 is an independent individual, and there is no magnetic bridge connecting two adjacent second punching sheet units 210. The outer contour of each second punching sheet unit 210 can be the same. Therefore, the types of molds can be reduced, which is convenient for blanking processing and is beneficial to improving production efficiency and reducing production costs.

[0046] It can be understood that after the plurality of first rotor punching sheets 100 of any one of the above embodiments and the plurality of second rotor punching sheets 200 are stacked axially, the plurality of first punching sheet units 110 on each first rotor punching sheet 100 and the plurality of second punching sheet units 210 on each second rotor punching sheet 200 are arranged axially in one-to-one correspondence. The plurality of first punching sheet units 110 and the plurality of second punching sheet units 210 arranged axially in correspondence form a core unit. That is to say, the rotor core includes a plurality of core units. The number of the core units is equal to the number of the first punching sheet units 110 on each first rotor punching sheet 100. The plurality of core units are arranged at intervals around the rotation axis, and an installation groove 300 is defined between two adjacent core units. That is to say, the installation groove 300 is located between two adjacent first punching sheet units 110 in the circumferential direction, and is also located between two adjacent second punching sheet units 210 in the circumferential direction. The installation groove 300 axially penetrates through the two axial end faces of the rotor core.

[0047] It can be understood that the rotor assembly further includes a plurality of permanent magnets. The number of the permanent magnets is equal to the number of the installation grooves 300, or the number of the permanent magnets is an integer multiple of the number of the installation grooves 300. The plurality of permanent magnets are installed in the corresponding installation grooves 300. That is to say, one permanent magnet is installed in each installation groove 300, or a plurality of permanent magnets are installed in each installation groove 300. The wall surface (i.e., the outer side wall surface) of the permanent magnet facing away from the rotation axis abuts against the outer magnetic bridge 120. Thus, the outer limit of the permanent magnet can be realized through the outer magnetic bridge 120. And when the motor runs at high speed, the outer magnetic bridge 120 can provide sufficient supporting force for each permanent magnet. The direction of the supporting force is along the radial direction of the rotor core and points to the rotation axis. Thus, the supporting force can offset the centrifugal force, making the permanent magnet firmly installed and avoiding the loosening of the permanent magnet, which is beneficial to improving the stability of the motor running at high speed.

[0048] It can be understood that, in some other embodiments, for the first rotor punching sheet 100 which further includes an inner magnetic bridge 130, the wall surface of the permanent magnet close to the rotation axis (i.e., the inner side wall surface) abuts against the inner magnetic bridge 130, so that the inner side limit of the permanent magnet can be realized through the inner magnetic bridge 130, making the installation of the permanent magnet more firm and the overall structure of the rotor assembly more stable.

[0049] It can be understood that, generally speaking, the rotor assembly further includes a plastic coating body which covers the two axial end faces of the rotor core, and the plastic coating body fills the gap between the permanent magnet and the rotor core, thereby further enhancing the overall stability of the rotor assembly.

[0050] It can be understood that, in some other embodiments, for the first rotor punching sheet 100 which further includes an inner magnetic bridge 130, a plurality of inner magnetic bridges 130 are sequentially connected to form a polygonal structure, generally a regular polygon, and the inner contour of the structure formed by sequentially connecting the plurality of inner magnetic bridges 130 is a regular polygon. Therefore, when the plastic coating body fills between the plurality of inner magnetic bridges 130 and the rotating shaft, the torque transmission capacity between the rotating shaft and the rotor core can be increased, improving the reliability.

[0051] It can be understood that since the magnetic force lines of the magnetic field of the permanent magnet can form a closed loop through the magnetic bridge between two adjacent core units, resulting in magnetic leakage, the magnetic force lines of this part do not pass through the stator assembly of the motor, which will lead to a decrease in the utilization rate of the magnetic field of the permanent magnet and a decrease in the efficiency of the motor.

[0052] For this reason, referring to Figure 1 and Figure 4 as shown, it can be understood that in the rotor core, by disconnecting (i.e., without a connecting magnetic bridge) between two adjacent second punching units 210 of the second rotor punching sheet 200, therefore, the volume of the connecting structure (i.e., the magnetic bridge) between two adjacent core units can be reduced, making the magnetic flux of the connecting structure between two adjacent core units prone to saturation, so as to reduce the magnetic leakage of the permanent magnet, and further improve the efficiency of the motor. It is easy to understand that since the magnetic bridge of the second rotor punching sheet 200 is omitted, the material usage of the rotor core is also reduced, which is beneficial to reducing the manufacturing cost. At the same time, by connecting two adjacent first punching units 110 of the first rotor punching sheet 100 through an outer magnetic bridge 120, both the overall structural strength of the rotor core can be ensured and sufficient radial support force can be provided for the permanent magnet during the high-speed operation of the motor to offset the centrifugal force, thereby improving the stability during the high-speed operation of the motor. Therefore, the rotor core composed of the above-mentioned first rotor punching sheet 100 and second rotor punching sheet 200 can not only reduce magnetic leakage, improve the efficiency of the motor, but also improve the structural stability of the rotor core and the stability during the high-speed operation of the motor.

[0053] Referring to Figure 1As shown, it can be understood that for the first rotor punching 100 that does not include the internal magnetic bridge 130, the volume of the connecting structure (i.e., the magnetic bridge) between the inner ends of two adjacent core units can be further reduced, thereby further reducing the leakage flux of the permanent magnet and improving the efficiency of the motor.

[0054] Reference Figure 7 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.

[0055] Referring to Table 1, it can be understood that, under the premise of a rotation speed of 1800 rpm and a torque of 1.1 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%.

[0056] Table 1 Motor performance comparison

[0057] This solution Existing technical solution Rotational speed (rpm) 1800 1800 Torque (Nm) 1.1 1.1 Efficiency (%) 82 81

[0058] Reference Figure 4 As shown, it can be understood that, in order to further improve the installation stability of the permanent magnet, for the second rotor punching sheet 200, the two adjacent second punching sheet units 210 are further provided with protrusions 220 on the opposite sides, and the two 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 that are arranged relatively along the circumference of the rotor core, and the two protrusions 220 are disconnected. Therefore, the protrusion 220 can contact the wall surface (i.e., the outer wall surface) on the permanent magnet that is away from the axis of rotation, so as to limit the permanent magnet and further improve the installation stability of the permanent magnet. It is easy to understand that since the two adjacent protrusions 220 located in the mounting groove 300 are disconnected, the protrusion 220 will not cause permanent magnet leakage, and the efficiency of the motor is effectively guaranteed.

[0059] Reference Figure 5As shown, it can be understood that in some other embodiments, the second punching unit 210 includes a main body portion 211, and the main body portion 211 is fan-shaped. In each second rotor punching 200, at least one second punching unit 210 further includes a limiting portion 212. Specifically, the limiting portion 212 is connected to one end of the main body portion 211 close to the rotation axis, and the limiting portion 212 protrudes from both side wall surfaces of the main body portion 211 along the circumferential direction of the rotor core. For example, in each second rotor punching 200, one or two or three second punching units 210 include the limiting portion 212, and the other second punching units 210 do not include the limiting portion 212; or all the second punching units 210 in each second rotor punching 200 include the limiting portion 212. Therefore, the protruding portions at both circumferential ends of each limiting portion 212 can respectively abut against the wall surfaces (i.e., the inner side wall surfaces) of two adjacent permanent magnets close to the rotation axis, thereby further improving the installation stability of the permanent magnets, and the limiting portion 212 does not connect two adjacent second punching units 210, so that the limiting portion 212 does not cause magnetic leakage, effectively ensuring the efficiency of the motor.

[0060] Referring to Figure 5 As shown, it can be understood that among any two adjacent second punching units 210, one second punching unit 210 includes a limiting portion 212. That is to say, in each second rotor punching 200, the second punching units 210 including the limiting portion 212 and the second punching 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 200, the number of the limiting portions 212 is half of the number of the second punching units 210, and the plurality of limiting portions 212 are evenly distributed along the circumferential direction of the rotor core. At this time, the outer shapes of half of the second punching units 210 are the same, and the outer shapes of the other half of the second punching units 210 are the same, and the number of the limiting portions 212 is only half of the number of the second punching units 210. Therefore, only half of the second punching units 210 are provided with the limiting portions 212, which can limit the inner side wall surfaces of each permanent magnet, ensuring the installation stability of the permanent magnets and reducing the material consumption, thereby reducing the production cost.

[0061] It can be understood that in the rotor core, the second rotor punching 200 can be any of the above embodiments; or the second rotor punching 200 includes the above two embodiments. Among them, only one second rotor punching 200 including the limiting portion 212 can be provided, or only the second rotor punchings 200 at both axial ends of the rotor core include the limiting portion 212, or only one or more second rotor punchings 200 at the middle position along the axis of the rotor core include the limiting portion 212, or the second rotor punching 200 at the middle of every three second rotor punchings 200 includes the limiting portion 212. Details are not described herein again.

[0062] Referring to Figure 2 as shown, it can be understood that along the radial direction of the rotor core, the minimum width of the outer magnetic bridge 120 is L1. Define the two wall surfaces of the outer magnetic bridge 120 that are radially away from each other along the rotor core as the first wall surface 121 and the second wall surface 122 respectively. Among them, the first wall surface 121 is located on the side of the outer magnetic bridge 120 away from the rotation axis, and the second wall surface 122 is located on the side of the outer magnetic bridge 120 close to the rotation axis. Therefore, the minimum width L1 of the outer magnetic bridge 120 is the minimum distance between the first wall surface 121 and the second wall surface 122. When measuring, it can be directly clamped at the position where the distance between the first wall surface 121 and the second wall surface 122 is the smallest by a vernier caliper.

[0063] Referring to Figure 1 and Figure 2 as shown, it can be understood that define the maximum distance between the wall surface of the outer magnetic bridge 120 away from the rotation axis and the rotation axis as L2, that is, the maximum distance between the first wall surface 121 and the rotation axis 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, limited by the overall size of the motor, the maximum outer diameter of the rotor core is basically determined. If L1 / L2 < 0.01, it will cause the minimum width of the outer magnetic bridge 120 to be too small, with great processing difficulty and low connection strength, 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 prone to deformation or fracture, with poor limiting and supporting effects on the permanent magnet, and it 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, increasing the magnetic leakage of the permanent magnet and affecting the efficiency of the motor. Therefore, 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., can effectively reduce the magnetic leakage of the permanent magnet, improve the efficiency of the motor, and is beneficial to reducing the processing difficulty of the first rotor punching sheet 100 on the premise of ensuring the stability of the rotor core and the installation stability of the permanent magnet.

[0064] It can be understood that for the first rotor punching sheet 100 including the inner magnetic bridge 130, 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 elaborated 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 simultaneously satisfy: 0.35 mm ≤ L1 ≤ 1.5 mm, for example, L1 = 0.5 mm or L1 = 1 mm, etc.

[0065] Referring to Figure 1 and Figure 6As 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.

[0066] Reference Figure 5 and Figure 6As shown, it can be understood that the minimum protruding height of the limiting portion 212 relative to the wall surface of the main body portion 211 is W1. It is defined that one end of the limiting portion 212 away from the main body portion 211 has a fifth wall surface 2123, and W1 is the minimum distance between the fifth wall surface 2123 and the wall surface of the main body portion 211 to which the limiting portion 212 is connected and facing the installation groove 300 and having the same orientation as the fifth wall surface 2123. The minimum distance between the opposite two wall surfaces of two adjacent main body portions 211 along the circumferential direction of the rotor core is W2, and W2 is the minimum distance between the two wall surfaces of the installation groove 300 arranged oppositely along the circumferential direction of the rotor core. W1 and W2 satisfy: 0.05 ≤ W1 / W2 ≤ 0.5. Generally speaking, according to the magnet consumption of the motor, the width of the permanent magnet along the circumferential direction 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, resulting in great processing difficulty, low structural strength, easy deformation, poor limiting effect on the permanent magnet, easy loosening of the permanent magnet, and affecting the installation stability of the permanent magnet; since the limiting portion 212 only provides an auxiliary limiting function for the permanent magnet, there is no need to set it too large. If W1 / W2 > 0.5, the minimum protruding height of the limiting portion 212 is too large, causing material waste and high manufacturing cost. Therefore, making 0.05 ≤ W1 / W2 ≤ 0.5, for example, the value of W1 / W2 is 0.1, 0.2, 0.3 or 0.5, etc., can effectively reduce the manufacturing cost and is beneficial to reducing the processing difficulty on the premise of ensuring the installation stability of the permanent magnet. It is easy to understand that the minimum protruding height W1 of the limiting portion 212 also satisfies: 0.4 mm ≤ W1 ≤ 1.8 mm, for example, W1 = 0.5 mm or W1 = 1 mm, etc.

[0067] The rotor assembly according to the embodiment of the second aspect of the present utility model includes the rotor core according to the embodiment of the first aspect of the present utility model and a plurality of permanent magnets, which will not be elaborated here.

[0068] Since the rotor assembly adopts all the technical solutions of the rotor core in the above embodiment, it at least has all the beneficial effects brought by the technical solutions of the above embodiment.

[0069] The motor according to the embodiment of the third aspect of the present utility model includes a stator assembly and the rotor assembly according to the embodiment of the second aspect of the present utility model, and the stator assembly is arranged around the outer periphery of the rotor assembly. The motor can be applied to compressors, blowers, washing machines, etc. of air conditioners or refrigerators.

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

[0071] The household appliance according to the embodiment of the fourth aspect of the present utility model includes the motor according to the embodiment of the third aspect of the present utility model. The household appliance may be a blower, an air conditioner, a refrigerator, a washing machine, etc.

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

[0073] The embodiments of the present utility model have been described in detail above with reference to the drawings. However, the present utility model is not limited to the above embodiments, and various changes can be made without departing from the gist of the present utility model within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. Rotor core, having a rotation axis, characterized in that, Comprising: A first rotor punching sheet, including a plurality of first punching units arranged at intervals around the rotation axis and an outer magnetic bridge. Any two adjacent first punching units are connected by one of the outer magnetic bridges, and the outer magnetic bridge is located at one end of the first punching unit away from the rotation axis; A second rotor punching sheet, including a plurality of second punching units arranged at intervals around the rotation axis. There is a break between two adjacent second punching units, and the second rotor punching sheet and the first rotor punching sheet are stacked along the direction of the rotation axis; The second punching unit includes a main body part. Among any two adjacent second punching units, one of the second punching units further includes a limiting part, and the limiting part is connected to one end of the main body part close to the rotation axis. The limiting part protrudes from two walls of the main body part that are opposite to each other along the circumferential direction of the rotor core.

2. The rotor core according to claim 1, wherein: The first rotor punching sheet further includes an inner magnetic bridge. Any two adjacent first punching units are also connected by one of the inner magnetic bridges, and the inner magnetic bridge is located at one end of the first punching unit close to the rotation axis.

3. The rotor core according to claim 2, characterized in that: A plurality of the inner magnetic bridges are connected in sequence and the inner contour is a polygon.

4. The rotor core according to claim 1, characterized in that: The minimum protruding height of the limiting part relative to the wall surface of the main body part is W1, and the minimum distance between two opposite wall surfaces of two adjacent main body parts along the circumferential direction of the rotor core is W2, satisfying: 0.05 ≤ W1 / W2 ≤ 0.

5.

5. The rotor core according to claim 1, characterized in that: The maximum distance between the wall surface of the outer magnetic bridge facing away from the rotation axis and the rotation axis is L2, and the minimum width of the limiting part along the radial direction of the rotor core is L3, satisfying: 0.01 ≤ L3 / L2 ≤ 0.

04.

6. The rotor core according to claim 1, wherein: Along the radial direction of the rotor core, the minimum width of the outer magnetic bridge is L1, and the maximum distance between the wall surface of the outer magnetic bridge facing away from the rotation axis and the rotation axis is L2, satisfying: 0.01 ≤ L1 / L2 ≤ 0.

06.

7. Rotor assembly, characterized in that, Comprising: The rotor core according to any one of claims 1 to 6, the rotor core including 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, respectively installed in the corresponding installation grooves.

8. Electric motor, characterized in that, Comprising a stator assembly and the rotor assembly according to claim 7, and the stator assembly is disposed around the outer periphery of the rotor assembly.

9. A household appliance, characterized in that, Comprising the motor according to claim 8.

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