Motor and household appliance

Abstract

The utility model discloses a motor and a household electrical appliance, the motor comprises a stator assembly and a rotor assembly, the stator assembly comprises a stator core and a plurality of windings, the stator core is provided with a plurality of winding grooves, the plurality of winding grooves are arranged at intervals along the circumferential direction of the stator core, and the plurality of windings are wound on the stator core and are respectively and correspondingly accommodated in the plurality of winding grooves; the rotor assembly comprises a rotor core and a plurality of permanent magnets, the rotor core is arranged around the periphery of the stator assembly, the permanent magnets are arranged on the side, facing the stator assembly, of the rotor core, and the permanent magnets are arranged at intervals in the circumferential direction; wherein the number of the winding grooves is M, the number of the permanent magnets is N, the maximum outer diameter of the stator core is D1, the maximum outer diameter of the rotor core is D2, and M-N / M is larger than or equal to 0.1 and smaller than or equal to 0.2, or M-N / M is larger than or equal to 0.3 and smaller than or equal to 0.4, and D1 / D2 is larger than or equal to 0.78 and smaller than or equal to 0.88. The motor provided by the utility model can improve the efficiency and reduce the vibration and noise, and is lower in production cost.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, in particular to a motor and a household appliance. Background Art

[0002] Brushless DC motors are widely used in various household appliances due to their simple structure and reliable operation. As one of the core components of household appliances, the performance of household appliances is closely related to the performance of the motor. In the relevant technology, the efficiency of the motor is generally low, the vibration and noise are large, and it cannot meet the needs of household appliances for high energy efficiency and quietness. At the same time, in the market environment that pursues high cost performance, how to strike a balance between the production cost of the motor and the efficiency and noise is a problem that still needs to be solved. 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 motor that can improve efficiency and reduce vibration and noise, and has a low production cost.

[0004] The utility model also provides a household appliance with the motor.

[0005] According to the first aspect of the present invention, the motor comprises a stator assembly, comprising a stator core and a plurality of windings, wherein the stator core is provided with a plurality of winding slots, the plurality of winding slots are arranged at intervals along the circumference of the stator core, and the plurality of windings are wound around the stator core and respectively accommodated in the plurality of winding slots;

[0006] A rotor assembly, comprising a rotor core and a plurality of permanent magnets, wherein the rotor core is arranged around the outer circumference of the stator assembly, the permanent magnets are arranged on a side of the rotor core facing the stator assembly, and the plurality of permanent magnets are arranged at intervals along the circumference of the rotor core;

[0007] Among them, the number of the winding slots is M, the number of the permanent magnets is N, the maximum outer diameter of the stator core is D1, and the maximum outer diameter of the rotor core is D2, satisfying: 0.1≤|MN| / M≤0.2 or 0.3≤|MN| / M≤0.4, 0.78≤D1 / D2≤0.88.

[0008] The motor according to the embodiment of the first aspect of the utility model has at least the following beneficial effects: the number M of winding slots and the number N of permanent magnets satisfy 0.1≤|MN| / M≤0.2 or 0.3≤|MN| / M≤0.4, the maximum outer diameter of the stator core and the maximum outer diameter of the rotor core satisfy 0.78≤D1 / D2≤0.88, thereby optimizing the number of slot poles of the motor and the outer diameter of the stator core and the outer diameter of the rotor core, and reducing the magnetic resistance, the magnetic flux saturation of the stator core, and the iron loss while keeping the amount of permanent magnets, the amount of windings, and the amount of core material at a relatively low level, that is, at a relatively low production cost, thereby improving the utilization of the magnetic field of the permanent magnet and the armature magnetic field, and further improving the efficiency of the motor; at the same time, it is possible to reduce the degree of distortion of the air gap magnetic field, reduce the tangential force caused by the air gap magnetic field, reduce the torque pulsation, and thus reduce vibration and noise.

[0009] According to some embodiments of the present invention, along the radial direction of the rotor core, the minimum width of the rotor core is W1, and the maximum width of the permanent magnet is W2, satisfying: 0.4≤W1 / W2≤0.55.

[0010] According to some embodiments of the present invention, along the axial direction of the stator core, the maximum height of the stator core is H1, and the maximum height of the permanent magnet is H2, satisfying: H2>H1.

[0011] According to some embodiments of the present invention, along the axial direction, the maximum height of the rotor core is H3, satisfying: H2≥H3.

[0012] According to some embodiments of the present invention, along the axial direction, the maximum height of the rotor core is H3, satisfying: H3 ≥ H1.

[0013] According to some embodiments of the present invention, the stator core includes a plurality of stator teeth arranged in sequence along the circumferential direction, the winding slot is defined between two adjacent stator teeth, the stator teeth include tooth portions arranged along the radial direction of the stator core, the minimum width of the tooth portions along the circumferential direction is W3, and satisfies: 0.55≤W3 / (H3+H2-2H1)≤0.75.

[0014] According to some embodiments of the present invention, the minimum inner diameter of the rotor core is D3, the permanent magnet has a first wall surface and a second wall surface that are opposite to each other along the circumferential direction, and in a reference circle whose center is the rotation center of the rotor core and whose diameter is the D3, the length of the minor arc between the plane where the first wall surface is located and the plane where the second wall surface is located is L, satisfying: 0.91≤L*N / (π*D3)≤0.97.

[0015] According to some embodiments of the present invention, the minimum inner diameter of the stator core is D4, which satisfies: 0.7≤2*π*D1 / (M*(D1-D4))≤0.9.

[0016] According to some embodiments of the present invention, the stator core includes a plurality of stator teeth arranged in sequence along the circumferential direction, the winding slot is defined between two adjacent stator teeth, the stator teeth include a yoke portion and a tooth portion, the tooth portion is arranged on a side of the yoke portion away from the rotation center of the rotor core, and two wall surfaces of two adjacent yoke portions arranged opposite to each other along the circumferential direction conflict with each other.

[0017] According to some embodiments of the present invention, the stator tooth further includes a boot portion, the boot portion is provided on a side of the tooth portion away from the yoke portion, and the boot portion protrudes from both sides of the tooth portion along the circumferential direction.

[0018] The household appliance according to the embodiment of the second aspect of the utility model comprises the motor according to the embodiment of the first aspect of the utility model.

[0019] According to the household appliance of the embodiment of the second aspect of the utility model, at least the following beneficial effects are achieved: since the household appliance adopts the above-mentioned motor, the number M of winding slots and the number N of permanent magnets satisfy 0.1≤|MN| / M≤0.2 or 0.3≤|MN| / M≤0.4, and the maximum outer diameter of the stator core and the maximum outer diameter of the rotor core satisfy 0.78≤D1 / D2≤0.88, thereby optimizing the number of slot poles of the motor and the outer diameter of the stator core and the outer diameter of the rotor core, and while keeping the amount of permanent magnets, windings and core materials at a relatively low level, that is, at a relatively low production cost, the magnetic resistance can be reduced, the magnetic flux saturation of the stator core can be reduced, and the iron loss can be reduced, thereby improving the utilization of the magnetic field of the permanent magnet and the armature magnetic field, thereby improving the efficiency of the motor; at the same time, the distortion degree of the air gap magnetic field can be reduced, the tangential force caused by the air gap magnetic field can be reduced, the torque pulsation can be reduced, and thus vibration and noise can be reduced.

[0020] 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

[0021] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0022] Figure 1 is an axial cross-sectional view of a motor in some embodiments of the utility model;

[0023] Figure 2 yes Figure 1 A in the enlarged view;

[0024] Figure 3 is an axial schematic diagram of a rotor core in some embodiments of the utility model;

[0025] Figure 4 is an axial schematic diagram of a permanent magnet in some embodiments of the utility model;

[0026] Figure 5 is an axial schematic diagram of stator teeth in some embodiments of the utility model;

[0027] Figure 6 It is a cross-sectional schematic diagram of the coordination of the rotor core, the permanent magnet, the stator core and the winding in some embodiments of the utility model;

[0028] Figure 7 is an axial cross-sectional view of a motor in some other embodiments of the utility model;

[0029] Figure 8 is a graph showing the efficiency of the motor in some embodiments of the present invention as a function of the value of |MN| / M;

[0030] Fig. 9 is a graph showing the torque ripple of the motor in some embodiments of the present invention as a function of the value of |MN| / M;

[0031] Fig.10 is a graph showing the efficiency of the motor in some embodiments of the present invention as a function of the value of D1 / D2;

[0032] Fig.11 is a graph showing the efficiency of the motor in some embodiments of the present invention as a function of the value of W1 / W2;

[0033] Fig.12 is a graph showing the efficiency of the motor in some embodiments of the present invention as a function of the value of W3 / (H3+H2-2H1);

[0034] Fig.13 is a graph showing the efficiency of the motor in some embodiments of the present invention as a function of the value of L*N / (π*D3);

[0035] Fig.14 is a graph showing the torque pulsation of the motor in some embodiments of the present invention as a function of the value of L*N / (π*D3);

[0036] Fig.15 It is a graph showing the change of the efficiency of the motor with the value of 2*π*D1 / (M*(D1-D4)) in some embodiments of the present invention.

[0037] Reference numerals:

[0038] stator assembly 100; stator core 110; stator teeth 111; tooth portion 1111; yoke portion 1112; shoe portion 1113; seventh wall surface 1114; eighth wall surface 1115; winding slot 112; winding 120;

[0039] Rotor assembly 200 ; rotor core 210 ; third wall 211 ; fourth wall 212 ; permanent magnet 220 ; first wall 221 ; second wall 222 ; fifth wall 223 ; and sixth wall 224 . DETAILED DESCRIPTION

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] Brushless DC motors are widely used in various household appliances due to their simple structure and reliable operation. As one of the core components of household appliances, the performance of household appliances is closely related to the performance of the motor. In the relevant technology, the efficiency of the current motors is generally low, and the vibration and noise are large, which cannot meet the needs of household appliances for high energy efficiency and quietness. At the same time, in the market environment that pursues high cost performance, how to strike a balance between the production cost of the motor and the efficiency and noise is a problem that still needs to be solved.

[0045] For this purpose, refer to Figures 1 to 15 As shown, the first embodiment of the utility model provides a motor for use in household appliances, where the household appliances may be air conditioners, refrigerators, washing machines, dryers, and the like.

[0046] Reference Figure 1 As shown, it can be understood that the motor includes a stator assembly 100 and a rotor assembly 200, wherein the rotor assembly 200 is arranged around the outer periphery of the stator assembly 100, and the rotor assembly 200 can rotate relative to the stator assembly 100, that is, the motor is an outer rotor motor. The rotation axis of the rotor assembly 200 is also the rotation center.

[0047] Reference Figure 1 As shown, it can be understood that the stator assembly 100 includes a stator core 110 and a plurality of windings 120, wherein the stator core 110 is annular and has a central axis, and the central axis coincides with the rotation axis. The stator core 110 includes a plurality of stator teeth 111, and each stator tooth 111 is an independent structure, that is, the stator core 110 is a block structure. The plurality of stator teeth 111 are arranged in sequence along the circumference of the stator assembly 100, and the circumference is the direction around the rotation axis. The side walls of the two adjacent stator teeth 111 at one end close to the rotation axis along the circumference of the stator assembly 100 conflict with each other, so that the plurality of stator teeth 111 are assembled into a ring shape. It is easy to understand that the two adjacent stator teeth 111 can be fixed by welding or connected by a dovetail structure, and the connection is stable.

[0048] Reference Figure 1 As shown, it can be understood that a winding slot 112 is defined between two adjacent stator teeth 111. It is easy to understand that the number of the winding slots 112 is equal to the number of the stator teeth 111, and the plurality of winding slots 112 are arranged at intervals along the circumferential direction of the stator core 110. The plurality of windings 120 are respectively wound around the plurality of stator teeth 111 and respectively accommodated in the plurality of winding slots 112. The number of winding slots 112 is defined as M, that is, the number of stator teeth 111 is also M.

[0049] Reference Figure 1 and Figure 5As shown, it can be understood that the stator tooth 111 includes a tooth portion 1111, a yoke portion 1112 and a boot portion 1113, wherein the tooth portion 1111 is arranged along the radial direction of the stator core 110, the yoke portion 1112 is connected to the inner end of the tooth portion 1111, that is, the yoke portion 1112 is connected to the end of the tooth portion 1111 close to the rotation axis, that is, the tooth portion 1111 is arranged on the side of the yoke portion 1112 away from the rotation axis; the boot portion 1113 is connected to the outer end of the tooth portion 1111, that is, the boot portion 1113 is connected to the end of the tooth portion 1111 away from the rotation axis, and the boot portion 1113 protrudes from both sides of the tooth portion 1111 along the circumferential direction of the stator core 110. The yoke portion 1112 is generally fan-shaped, and the two wall surfaces of two adjacent yoke portions 1112 arranged opposite to each other along the circumferential direction of the stator core 110 are in conflict with each other. Two adjacent stator teeth 111 are welded together through the yoke 1112, or two adjacent stator teeth 111 are connected together through the yoke 1112 in a dovetail structure. The winding 120 is wound around the tooth 1111. At the same time, the boot 1113 and the yoke 1112 can limit the radial ends of the winding 120 respectively to prevent the winding 120 from falling off, thereby improving the reliability of the stator assembly 100. The notch of the winding slot 112 is defined between two adjacent boots 1113. It is easy to understand that the side close to the axis of rotation is the "inside", and the side away from the axis of rotation is the "outside".

[0050] Reference Figure 1 As shown, it can be understood that, since the stator core 110 is a block structure, when assembling the stator assembly 100, the winding 120 can be firstly wound on each stator tooth 111, and then the multiple stator teeth 111 can be assembled into a ring shape. Therefore, it is not necessary to reserve a space in the winding slot 112 for the winding nozzle to exit, so that the winding 120 can fill more winding slot 112 space, thereby improving the slot fill rate of the stator assembly 100, which is conducive to improving the output power and efficiency of the motor.

[0051] Reference Figure 1As shown, it can be understood that the rotor assembly 200 includes a rotor core 210 and a plurality of permanent magnets 220, wherein the rotor core 210 is annular and is arranged around the outer periphery of the stator core 110, and the central axis of the rotor core 210 coincides with the central axis of the stator core 110, and the central axis of the rotor core 210 is also the rotation axis of the rotor assembly 200. There is an installation space between the rotor core 210 and the stator core 110, and the permanent magnet 220 is arranged on the side of the rotor core 210 facing the stator assembly 100, that is, the permanent magnet 220 is arranged on the inner peripheral wall of the rotor core 210, that is, the permanent magnet 220 is located in the above-mentioned installation space. The permanent magnet 220 can be bonded and fixed to the rotor core 210. The plurality of permanent magnets 220 are arranged at equal intervals along the circumference of the rotor core 210, and each permanent magnet 220 is a magnetic pole of the rotor assembly 200. There is a gap, ie, an air gap, between the inner wall of the permanent magnet 220 and the outer peripheral wall of the stator core 110. The number of the permanent magnets 220 is defined as N, that is, the number of magnetic poles of the rotor assembly 200 is also defined as N.

[0052] It can be understood that the number M of the winding slots 112 and the number N of the permanent magnets 220 satisfy: 0.1≤|MN| / M≤0.2 or 0.3≤|MN| / M≤0.4. That is, the absolute value of the difference between the number of winding slots 112 and the number of permanent magnets 220 and the ratio of the number of winding slots 112 are 0.1 to 0.2 or 0.3 to 0.4. Since the number of permanent magnets 220 is equal to the number of magnetic poles of the rotor assembly 200, |MN| / M can be understood as the slot-to-pole ratio coefficient of the motor, which is used to indicate the quantitative relationship between the winding slots 112 and the magnetic poles of the motor, that is, indirectly indicates the slot-to-pole ratio of the motor.

[0053] Reference Figure 1 As shown, it can be understood that, in this embodiment, the number M of the winding slots 112 is 12, the number N of the permanent magnets 220 is 10, and |MN| / M≈0.167, which is within the range of 0.1 to 0.2.

[0054] Reference Figure 7 As shown, it can be understood that, in other embodiments, the number of the winding slots 112 is M=12, the number of the permanent magnets 220 is N=16, and |MN| / M≈0.333, which is within the range of 0.3 to 0.4.

[0055] Reference Figure 1 and Figure 7As shown, it can be understood that if the number of winding slots 112 is large, that is, the number of stator teeth 111 is large, the number of joints between two adjacent stator teeth 111 increases, and the joint is the position where two adjacent stator teeth 111 conflict with each other (that is, the position where two adjacent yokes 1112 conflict with each other). It is easy to understand that the magnetic resistance of the joint between two adjacent stator teeth 111 is greater than the magnetic resistance of the core, so it will cause the magnetic resistance of the entire stator core 110 to increase, the magnetic field to weaken, and the output power and efficiency of the motor to decrease, that is, the performance of the motor to decrease. If the number of winding slots 112 is small, that is, the number of stator teeth 111 is small, the magnetic flux of the stator core 110 becomes smaller, which will also cause the performance of the motor to decrease; at the same time, the number of notches of the winding slots 112 is reduced. Under the premise that other parameters remain unchanged, such as the number of magnetic poles is the same, the fluctuation frequency of the tooth slot torque decreases, and the fluctuation amplitude of the tooth slot torque increases, that is, the torque pulsation increases, resulting in increased vibration and noise.

[0056] Reference Figure 1 and Figure 7 As shown, it can be understood that if the number of permanent magnets 220 is large, that is, the number of magnetic poles is large, since there is a gap between two adjacent permanent magnets 220, the total number of gaps between two adjacent permanent magnets 220 increases, the total amount of permanent magnets 220 decreases, and the magnetic field formed by the permanent magnets 220 weakens, which will lead to a decrease in the output power and efficiency of the motor, that is, the performance of the motor decreases. If the number of permanent magnets 220 is small, that is, the number of magnetic poles is small, the magnetic flux of each magnetic pole increases, and the magnetic flux saturation of the corresponding stator teeth 111 increases, resulting in an increase in iron loss, a decrease in the output power and efficiency of the motor, that is, the performance of the motor decreases; at the same time, the magnetic field of each magnetic pole is directed to different stator teeth 111, which will cause serious distortion of the air gap magnetic field, increase torque pulsation, and increase vibration and noise.

[0057] It can be understood that the number of winding slots 112, the number of permanent magnets 220 and the quantitative relationship between the winding slots 112 and the permanent magnets 220 (which can be understood as the slot-to-pole ratio of the motor) will affect the performance, vibration and noise level of the motor.

[0058] Reference Figure 8 and Fig. 9It is easy to understand that when |MN| / M<0.1, or 0.2<|MN| / M<0.3, or |MN| / M>0.4, the efficiency of the motor is about 83% or less, which is low efficiency; the torque pulsation percentage is about 3% or more, and the torque pulsation is large, which will lead to increased vibration and noise. When 0.1≤|MN| / M≤0.2 or 0.3≤|MN| / M≤0.4, the efficiency of the motor is about 83% or more, and the highest efficiency can reach about 85%, and the efficiency of the motor is significantly improved; the torque pulsation percentage is about 3% or less, and the lowest torque pulsation percentage is about 1.5%, which can significantly reduce the torque pulsation, thereby reducing vibration and noise.

[0059] Therefore, the number M of the winding slots 112 and the number N of the permanent magnets 220 satisfy 0.1≤|MN| / M≤0.2 or 0.3≤|MN| / M≤0.4, for example, the value of |MN| / M is 0.1, 0.15, 0.2, 0.3, 0.35 or 0.4, etc., which can optimize the number of winding slots 112 and the number of permanent magnets 220, optimize the quantitative relationship between the winding slots 112 and the permanent magnets 220, and optimize the slot-pole ratio of the motor, which can reduce the magnetic resistance, reduce the magnetic flux saturation of the stator core 110, and reduce the iron loss, thereby improving the utilization rate of the magnetic field of the permanent magnet 220, enhancing the magnetic field, increasing the magnetic flux of the stator core 110, and thus improving the output power and efficiency of the motor. At the same time, the fluctuation frequency of the cogging torque is increased, the fluctuation amplitude of the cogging torque is reduced, and the distortion degree of the air gap magnetic field is reduced, and the tangential force caused by the air gap magnetic field is reduced, thereby reducing the torque pulsation, vibration and noise.

[0060] Reference Figure 1 As shown, it can be understood that the maximum outer diameter of the stator core 110 is defined as D1, and the maximum outer diameter of the rotor core 210 is defined as D2, wherein D1 is twice the maximum distance between the outer peripheral wall of the stator core 110 and the central axis, and D2 is twice the maximum distance between the outer peripheral wall of the rotor core 210 and the central axis. In this embodiment, the maximum outer diameter D1 of the stator core 110 is the maximum distance between the two outer wall surfaces of the two stator teeth 111 arranged symmetrically about the central axis and facing each other in the radial direction of the stator core 110; the projection of the outer peripheral wall of the rotor core 210 on the projection plane perpendicular to the rotation axis is a circle with the center located at the rotation axis, and the maximum outer diameter D2 of the rotor core 210 is the diameter of the circle.

[0061] Reference Figure 1As shown, it can be understood that the maximum outer diameter D1 of the stator core 110 and the maximum outer diameter D2 of the rotor core 210 satisfy 0.78≤D1 / D2≤0.88. When the outer diameter of the motor housing is determined, that is, the maximum outer diameter of the rotor core 210 is a determined value, if D1 / D2<0.78, the maximum outer diameter of the stator core 110 is too small, which compresses the overall space of the stator assembly 100, the space of the winding slot 112 is limited, and the amount of the winding 120 is reduced, resulting in a weak armature magnetic field of the motor and reduced performance of the motor. If D1 / D2>0.88, the maximum outer diameter of the stator core 110 is too large, which compresses the overall space of the rotor assembly 200, that is, the distance between the inner side and the outer side of the rotor assembly 200 is narrow. If the radial thickness of the permanent magnet 220 is kept unchanged, the radial thickness of the rotor core 210 will be reduced, which will cause the rotor core 210 to easily experience magnetic flux saturation, and the magnetic field generated by the permanent magnet 220 cannot be fully utilized, resulting in a decrease in the output power and efficiency of the motor; if the radial thickness of the rotor core 210 is kept unchanged, the radial thickness of the permanent magnet 220 will be reduced, the total amount of the permanent magnet 220 is reduced, and the magnetic field strength generated by the permanent magnet 220 is weak, resulting in a decrease in the performance of the motor. Therefore, by making 0.78≤D1 / D2≤0.88, for example, the value of D1 / D2 is 0.78, 0.8, 0.85 or 0.88, etc., the radial dimensions of the stator assembly 100 and the rotor assembly 200 can be optimized, so that the usage of the permanent magnets 220 and the windings 120 is appropriate to improve the output power and efficiency of the motor.

[0062] Reference Fig.10 As shown, it can be understood that as the value of D1 / D2 increases, the efficiency of the motor first increases and then decreases. When 0.78≤D1 / D2≤0.88, the efficiency of the motor is maintained above about 82%, which can significantly improve the efficiency of the motor.

[0063] It can be understood that, in addition, by satisfying 0.1≤|MN| / M≤0.2 or 0.3≤|MN| / M≤0.4, and 0.78≤D1 / D2≤0.88, the performance of the motor and the amount of permanent magnet 220, winding 120, and core material can be taken into account at the same time, so that the amount of permanent magnet 220, the amount of winding 120, and the amount of core material can be kept at a relatively low level, that is, at a lower production cost, it is possible to improve the output power and efficiency of the motor and reduce vibration and noise.

[0064] Reference Figure 3 and Figure 4As shown, it can be understood that, along the radial direction of the rotor core 210, the minimum width of the rotor core 210 is W1, and the maximum width of the permanent magnet 220 is W2. It is easy to understand that the rotor core 210 has a third wall 211 and a fourth wall 212 that are radially opposite to each other, wherein the third wall 211 is the inner peripheral wall of the rotor core 210, and the fourth wall 212 is the outer peripheral wall of the rotor core 210. The minimum distance between the third wall 211 and the fourth wall 212 in the radial direction of the rotor core 210 is the minimum width W1 of the rotor core 210. When measuring W1, the position where the distance between the third wall 211 and the fourth wall 212 is the minimum can be measured by using a vernier caliper. The permanent magnet 220 has a fifth wall 223 and a sixth wall 224 which are radially opposite to each other in the rotor core 210, wherein the fifth wall 223 is closer to the rotation axis of the rotor assembly 200 than the sixth wall 224, and the minimum distance between the fifth wall 223 and the sixth wall 224 in the radial direction of the rotor core 210 is the maximum width W2 of the permanent magnet 220. When measuring W2, the position where the distance between the fifth wall 223 and the sixth wall 224 is the smallest can be measured by using a vernier caliper.

[0065] Reference Figure 3 and Figure 4 As shown, it can be understood that the minimum width W1 of the rotor core 210 and the maximum width W2 of the permanent magnet 220 satisfy: 0.4≤W1 / W2≤0.55. It is easy to understand that the ratio of W1 / W2 is one of the factors that determine the magnetic flux saturation state of the rotor core 210. If W1 / W2<0.4, the minimum width of the rotor core 210 is relatively small, the maximum width of the permanent magnet 220 is relatively large, and the magnetic field generated by the permanent magnet 220 is relatively strong, which will cause the rotor core 210 to pass through the magnetic saturation phenomenon, and the magnetic field of the permanent magnet 220 cannot be fully utilized, resulting in a decrease in the efficiency of the motor; if W1 / W2>0.55, the minimum width of the rotor core 210 is relatively large, the maximum width of the permanent magnet 220 is relatively small, and the magnetic field generated by the permanent magnet 220 is relatively weak, which will also cause a decrease in the efficiency of the motor. Therefore, setting 0.4≤W1 / W2≤0.55, for example, the value of W1 / W2 is 0.4, 0.45, 0.5 or 0.55, etc., can increase the magnetic field generated by the permanent magnet 220, avoid magnetic saturation in the rotor core 210, and improve the utilization rate of the magnetic field of the permanent magnet 220, thereby improving the efficiency of the motor and optimizing the performance of the motor.

[0066] Reference Fig.11 As shown, it can be understood that as the value of W1 / W2 increases, the efficiency of the motor first increases and then decreases. When 0.4≤W1 / W2≤0.55, the efficiency of the motor is maintained above about 75%, which can significantly improve the efficiency of the motor and thus optimize the performance of the motor.

[0067] Reference Figure 6 As shown, it can be understood that along the axial direction of the stator core 110, the axial direction is the direction of the rotation axis, and the maximum height of the stator core 110 is defined as H1, the maximum height of the permanent magnet 220 is defined as H2, and the maximum height of the rotor core 210 is defined as H3. The maximum height H1 of the stator core 110 is the maximum distance between the two walls of the stator teeth 111 that are axially opposite to each other. Similarly, the maximum height H2 of the permanent magnet 220 is the maximum distance between the two walls of the permanent magnet 220 that are axially opposite to each other, and the maximum height H3 of the rotor core 210 is the maximum distance between the two walls of the rotor core 210 that are axially opposite to each other.

[0068] Reference Figure 6 As shown, it can be understood that the maximum height H1 of the stator core 110 and the maximum height H2 of the permanent magnet 220 satisfy: H2>H1. Generally speaking, the two ends of the permanent magnet 220 along the axial direction protrude from the two axially opposite walls of the stator tooth 111, and the magnetic field generated by the part of the permanent magnet 220 protruding from the two axially opposite walls of the stator tooth 111 can also be conducted to the stator tooth 111, which is conducive to improving the magnetic flux density of the stator core 110, thereby improving the output power and output torque of the motor, and optimizing the performance of the motor.

[0069] Reference Figure 6 As shown, it can be understood that the maximum height H2 of the permanent magnet 220 and the maximum height H3 of the rotor core 210 satisfy: H2≥H3. Generally speaking, at the same time, the maximum height H3 of the rotor core 210 and the maximum height H1 of the stator core 110 satisfy: H3≥H1. When H3=H1, the two axially opposite walls of the rotor core 210 correspond to the coplanarity of the two axially opposite walls of the stator teeth 111. When H3>H1, the two ends of the rotor core 210 in the axial direction protrude from the two axially opposite walls of the stator teeth 111. Similarly, when H2>H3, the two ends of the permanent magnet 220 in the axial direction protrude from the two axially opposite walls of the rotor core 210, thereby improving the magnetic flux density of the rotor core 210, thereby improving the output power and output torque of the motor, and optimizing the performance of the motor. When H2=H3, the two axially opposite wall surfaces of the permanent magnet 220 are coplanar with the two axially opposite wall surfaces of the rotor core 210, thereby reducing the magnetic flux saturation degree of the rotor core 210, making full use of the magnetic field generated by the permanent magnet 220, making the magnetic density of the rotor core 210 moderate, and optimizing the performance of the motor.

[0070] Reference Figure 5As shown, it can be understood that the minimum width of the tooth portion 1111 along the circumferential direction of the stator core 110 is defined as W3. Specifically, the tooth portion 1111 has a seventh wall surface 1114 and an eighth wall surface 1115 that are opposite to each other along the circumferential direction of the stator core 110, and W3 is the minimum distance between the seventh wall surface 1114 and the eighth wall surface 1115. Generally speaking, the seventh wall surface 1114 is parallel to the eighth wall surface 1115, and when measuring W3, the vernier caliper can be used to measure at the point where the distance between the seventh wall surface 1114 and the eighth wall surface 1115 is the minimum.

[0071] It is understandable that the minimum width of the tooth portion 1111 is one of the factors that determine the magnetic flux saturation state of the stator tooth 111. The smaller the minimum width of the tooth portion 1111, the easier it is for the magnetic flux of the stator tooth 111 to be saturated. Conversely, the magnetic flux of the stator tooth 111 is not easily saturated.

[0072] Reference Figure 5 and Figure 6As shown, it can be understood that the minimum width W3 of the tooth portion 1111, the maximum height H1 of the stator core 110, the maximum height H2 of the permanent magnet 220, and the maximum height H3 of the rotor core 210 satisfy: 0.55≤W3 / (H3+H2-2H1)≤0.75. Among them, H3+H2-2H1=H3-H1+H2-H1, that is, the sum of the axial height difference between the permanent magnet 220 and the stator core 110 and the axial height difference between the rotor core 210 and the stator core 110, can reflect the magnitude of the magnetic flux generated by the permanent magnet 220 and conducted to the stator core 110 to a certain extent. Under the premise that other factors remain unchanged, by increasing the maximum height H2 of the permanent magnet 220, the value of H3+H2-2H1 increases, which can increase the magnetic flux conducted to the stator core 110. If W3 / (H3+H2-2H1)<0.55, the minimum width W3 of the tooth portion 1111 is small, the value of H3+H2-2H1 is large, the magnetic flux saturation degree of the stator tooth 111 is high, and the magnetic density is large. On the one hand, the utilization rate of the magnetic field of the permanent magnet 220 is low, resulting in a decrease in the performance of the motor. On the other hand, due to the magnetic flux saturation of the stator tooth 111, the magnetic field generated by the permanent magnet 220 is partially transmitted to the slot of the winding slot 112, causing serious distortion of the air gap magnetic field, increased torque pulsation, and increased vibration and noise. If W3 / (H3+H2-2H1)>0.75, the minimum width W3 of the tooth portion 1111 is large, the value of H3+H2-2H1 is small, and the magnetic density of the stator tooth 111 is small, resulting in a decrease in the output power and efficiency of the motor, and the material of the stator tooth 111 increases, resulting in material waste. Therefore, setting 0.55≤W3 / (H3+H2-2H1)≤0.75, for example, the value of W3 / (H3+H2-2H1) is 0.55, 0.6, 0.65, 0.7 or 0.75, etc., can make the magnetic flux density level of the stator tooth 111 moderate, give full play to the performance of the motor at the same cost, improve the output power and efficiency of the motor, improve the cost performance, and at the same time, reduce vibration and noise.

[0073] Reference Fig.12 As shown, it can be understood that as the value of W3 / (H3+H2-2H1) increases, the efficiency of the motor first increases and then decreases. When 0.55≤W3 / (H3+H2-2H1)≤0.75, the efficiency of the motor is maintained above approximately 79.5%, which can significantly improve the efficiency of the motor and thus optimize the performance of the motor.

[0074] Reference Figure 1 As shown, it can be understood that the minimum inner diameter of the rotor core 210 is defined as D3, which is twice the minimum distance between the inner circumferential wall of the rotor core 210 and the central axis. In this embodiment, the projection of the inner circumferential wall of the rotor core 210 on the projection plane perpendicular to the rotation axis is a circle with the center located at the rotation axis, and the minimum inner diameter D3 of the rotor core 210 is the diameter of the circle.

[0075] Reference Figure 1 and Figure 2 As shown, it can be understood that the permanent magnet 220 has a first wall surface 221 and a second wall surface 222 that are opposite to each other along the circumferential direction of the rotor core 210. On the projection plane perpendicular to the rotation axis, the center of the circle is located in a reference circle with a diameter of D3 and the rotation axis (i.e., the rotation center). The reference circle is the projection of the inner circumferential wall of the rotor core 210. The arc length of the minor arc between the plane where the first wall surface 221 and the plane where the second wall surface 222 are located on the reference circle is defined as L. L can be understood as the maximum circumferential length of the permanent magnet 220 in the circumferential direction of the rotor core 210.

[0076] Reference Figure 1 and Figure 2 As shown, it can be understood that the number N of permanent magnets 220, the maximum circumferential length L of permanent magnets 220 and the minimum inner diameter D3 of rotor core 210 satisfy: 0.91≤L*N / (π*D3)≤0.97. L*N / (π*D3) can be understood as the ratio of the maximum circumferential length of permanent magnet 220 to the unit arc length, wherein the unit arc length is (π*D3) / N, which can be understood as the sum of the maximum circumferential lengths of permanent magnet 220 and the gap located on one side of the circumference thereof (i.e., the gap between two adjacent permanent magnets 220). Therefore, the value of L*N / (π*D3) can reflect the proportion of multiple permanent magnets 220 in the circumferential space of the inner circumference of rotor core 210. If L*N / (π*D3)<0.91, the maximum circumferential length of the permanent magnet 220 is small, the amount of permanent magnet 220 used is small, and the magnetic field generated by the permanent magnet 220 is weak, resulting in a decrease in the output power and efficiency of the motor. At the same time, the gap between two adjacent permanent magnets 220 is large, which will cause the torque pulsation to increase and the vibration and noise to increase; if L*N / (π*D3)>0.97, the gap between two adjacent permanent magnets 220 is small, and the inter-pole leakage flux between two adjacent permanent magnets 220 is large, which affects the output power and efficiency of the motor. At the same time, it will also cause the torque pulsation to increase and the vibration and noise to increase. In addition, since the gap between two adjacent permanent magnets 220 is small, the assembly accuracy requirement is high, which is not conducive to assembly, and the amount of permanent magnets 220 used increases, which increases the cost. Therefore, making 0.91≤L*N / (π*D3)≤0.97, for example, the value of L*N / (π*D3) is 0.91, 0.93, 0.95 or 0.97, etc., can increase the magnetic field generated by the permanent magnet 220, while reducing leakage flux, improving the output power and efficiency of the motor, and reducing torque pulsation, reducing vibration and noise, while reducing the difficulty of assembly, improving assembly efficiency and reducing costs.

[0077] Reference Fig.13 and Fig.14As shown, it can be understood that as the value of L*N / (π*D3) increases, the efficiency of the motor first increases and then tends to be flat. When L*N / (π*D3)≥0.91, the efficiency of the motor remains above about 81%. When L*N / (π*D3)>0.97, the efficiency of the motor remains at about 84.5%, and the efficiency of the motor does not increase further. As the value of L*N / (π*D3) increases, the torque pulsation percentage first decreases and then increases. When 0.91≤L*N / (π*D3)≤0.97, the torque pulsation percentage remains below about 3.5%. Therefore, making 0.91≤L*N / (π*D3)≤0.97 can significantly improve the efficiency of the motor, thereby optimizing the performance of the motor, and at the same time can significantly reduce the torque pulsation, thereby reducing vibration and noise.

[0078] Reference Figure 1 As shown, it can be understood that the minimum inner diameter of the stator core 110 is defined as D4, which is twice the minimum distance between the inner circumferential wall of the stator core 110 and the central axis, that is, twice the minimum distance between the inner wall surface of the yoke 1112 and the central axis. In this embodiment, the projection of the inner circumferential wall of the stator core 110 on the projection plane perpendicular to the rotation axis is a circle with the center located at the rotation axis, and the minimum inner diameter D4 of the stator core 110 is the diameter of the circle.

[0079] Reference Figure 1As shown, it can be understood that the minimum inner diameter of the stator core 110 is D4, the number of stator teeth 111 (also the number of winding slots 112) M and the maximum outer diameter D1 of the stator core 110 satisfy: 0.7≤2*π*D1 / (M*(D1-D4))≤0.9. Among them, (π*D1) / M is the ratio of the circumference of the maximum circumscribed circle of the stator core 110 to the number of stator teeth 111, and (D1-D4) / 2 can be understood as the maximum length of the stator tooth 111 in the radial direction, that is, the maximum radial length of the stator tooth 111, and also the radial distance between the outer wall surface and the inner wall surface of the stator tooth 111 that are radially opposite to each other. 2*π*D1 / (M*(D1-D4)) is the ratio of (π*D1) / M to (D1-D4) / 2. 2*π*D1 / (M*(D1-D4)) can reflect the size and shape of the winding slot 112 to a certain extent. Generally speaking, the maximum outer diameter D1 of the stator core 110 is a fixed value. Under the premise that the number M of the stator teeth 111 is the same, that is, the value of (π*D1) / M is the same, if 2*π*D1 / (M*(D1-D4)) is less than 0.7, the value of (D1-D4) / 2 is larger, that is, the maximum radial length of the stator tooth 111 is larger, the inner end of the winding slot 112 (that is, the end close to the rotation axis) is smaller in the circumferential direction, and the winding 120 cannot fill the inner end of the winding slot 112, and the guide The slot filling rate is decreased, resulting in a decrease in the output power of the motor. At the same time, since the maximum radial length of the stator teeth 111 is large, the material consumption of the stator teeth 111 is large, the cost is high, and the iron loss is large, resulting in a decrease in the efficiency of the motor; if 2*π*D1 / (M*(D1-D4))>0.9, the maximum radial length of the stator teeth 111 is small, the area of ​​the winding slot 112 is small, resulting in a small amount of winding 120, and a small armature magnetic field of the motor, which also leads to a decrease in the output power of the motor. Therefore, 0.7≤2*π*D1 / (M*(D1-D4))≤0.9, for example, the value of 2*π*D1 / (M*(D1-D4)) is 0.7, 0.75, 0.8, 0.85 or 0.9, etc., which can increase the amount of winding 120 and improve the slot filling rate, thereby improving the output power and efficiency of the motor, and reducing the production cost of the stator core 110.

[0080] Reference Fig.15 As shown, it can be understood that as the value of 2*π*D1 / (M*(D1-D4)) increases, the efficiency of the motor first increases and then decreases. When 0.7≤2*π*D1 / (M*(D1-D4))≤0.9, the efficiency of the motor is maintained above approximately 82.5%, which can significantly improve the efficiency of the motor, thereby optimizing the performance of the motor.

[0081] The household appliance of the second embodiment of the utility model includes the motor of the first embodiment of the utility model, which will not be described in detail here.

[0082] 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.

[0083] 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 motor, characterized in that include: A stator assembly, comprising a stator core and a plurality of windings, wherein the stator core is provided with a plurality of winding slots, the plurality of winding slots are arranged at intervals along the circumference of the stator core, and the plurality of windings are wound around the stator core and respectively accommodated in the plurality of winding slots; A rotor assembly, comprising a rotor core and a plurality of permanent magnets, wherein the rotor core is arranged around the outer circumference of the stator assembly, the permanent magnets are arranged on a side of the rotor core facing the stator assembly, and the plurality of permanent magnets are arranged at intervals along the circumference of the rotor core; Among them, the number of the winding slots is M, the number of the permanent magnets is N, the maximum outer diameter of the stator core is D1, and the maximum outer diameter of the rotor core is D2, satisfying: 0.1≤|MN| / M≤0.2 or 0.3≤|MN| / M≤0.4, 0.78≤D1 / D2≤0.

88.

2. The motor according to claim 1, characterized in that: Along the radial direction of the rotor core, the minimum width of the rotor core is W1, and the maximum width of the permanent magnet is W2, satisfying: 0.4≤W1 / W2≤0.

55.

3. The motor according to claim 1, characterized in that: Along the axial direction of the stator core, the maximum height of the stator core is H1, and the maximum height of the permanent magnet is H2, satisfying: H2>H1.

4. The motor according to claim 3, characterized in that: Along the axial direction, the maximum height of the rotor core is H3, satisfying: H2≥H3.

5. The motor according to claim 3, characterized in that: Along the axial direction, the maximum height of the rotor core is H3, satisfying: H3 ≥ H1.

6. The motor according to claim 5, characterized in that: The stator core includes a plurality of stator teeth arranged in sequence along the circumferential direction, the winding slot is defined between two adjacent stator teeth, the stator teeth include tooth portions arranged along the radial direction of the stator core, the minimum width of the tooth portions along the circumferential direction is W3, and satisfies: 0.55≤W3 / (H3+H2-2H1)≤0.

75.

7. The motor according to claim 1, characterized in that: The minimum inner diameter of the rotor core is D3, and the permanent magnet has a first wall surface and a second wall surface that are opposite to each other along the circumferential direction. In a reference circle whose center is the rotation center of the rotor core and whose diameter is D3, the length of the minor arc between the plane where the first wall surface is located and the plane where the second wall surface is located is L, satisfying: 0.91≤L*N / (π*D3)≤0.

97.

8. The motor according to claim 1, characterized in that: The minimum inner diameter of the stator core is D4, which satisfies: 0.7≤2*π*D1 / (M*(D1-D4))≤0.

9.

9. The motor according to claim 1, characterized in that: The stator core includes a plurality of stator teeth arranged in sequence along the circumferential direction, the winding slot is defined between two adjacent stator teeth, the stator teeth include a yoke portion and a tooth portion, the tooth portion is arranged on a side of the yoke portion away from the rotation center of the rotor core, and two wall surfaces of two adjacent yoke portions arranged opposite to each other along the circumferential direction conflict with each other.

10. The motor according to claim 9, characterized in that: The stator tooth further includes a shoe portion, which is arranged on a side of the tooth portion away from the yoke portion, and the shoe portion protrudes from both sides of the tooth portion along the circumferential direction.

11. A household appliance, characterized in that Comprising a motor as claimed in any one of claims 1 to 10.

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