Motor, fan and electrical equipment

Abstract

The utility model discloses a motor, fan and electrical equipment, the motor comprises a stator assembly and a rotor assembly, the rotor assembly comprises a rotor iron core and a plurality of permanent magnets, and the rotor iron core comprises a plurality of iron core units arranged at intervals along the circumferential direction; the number of the permanent magnets is N, N is an even number, the minimum distance between the two permanent magnets which are symmetrically arranged about the central axis of the rotor iron core is D2, the maximum length of each permanent magnet is a, the maximum thickness of each permanent magnet is b, and the coefficient K meets the formula. On the premise that the motor is adaptive to rotating shafts with various diameter specifications, the output torque can be increased, the no-load back electromotive force is improved, the loss is reduced, and the operation efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to motor technical field, especially a kind of motor, fan and electrical equipment. BACKGROUND

[0002] With the performance improvement of electrical equipment, the performance requirement of motor in electrical equipment is also higher and higher. For motor, in order to provide versatility, the rotor of motor needs to adapt to various diameter specifications of rotating shaft, that is, the shaft hole of rotor needs to adapt to rotating shaft with larger diameter. However, the shaft hole with larger inner diameter will lead to the reduction of cross-sectional area of permanent magnet, the reduction of output torque of motor, and the reduction of efficiency under the same output torque. SUMMARY

[0003] The utility model at least solves one of the technical problems existing in the prior art. To this end, the utility model provides a motor, which can increase output torque, improve no-load back electromotive force, reduce loss and improve operating efficiency under the premise of adapting to various diameter specifications of rotating shaft.

[0004] The utility model further provides a fan and electrical equipment with the above motor.

[0005] According to the motor of the first aspect of the utility model, the motor comprises a stator assembly, a rotor assembly and a plurality of windings, the stator assembly comprises a stator core and the plurality of windings, the stator core is annular and is provided with an inner hole, the stator core comprises a stator yoke portion and a plurality of stator teeth, the plurality of stator teeth are connected to the inner peripheral wall of the stator yoke portion and are arranged at intervals along the circumferential direction of the stator core, and the plurality of windings are respectively wound on the plurality of stator teeth; the rotor assembly is rotatably arranged in the inner hole, and the rotor assembly comprises a rotor core and a plurality of permanent magnets, the rotor core comprises a plurality of core units arranged at intervals along the circumferential direction, an installation groove is defined between adjacent two core units, and the plurality of permanent magnets are correspondingly installed in the plurality of installation grooves; wherein the number of permanent magnets is N, N is an even number, the minimum distance between two permanent magnets arranged symmetrically about the central axis of the rotor core is D2, the maximum length of the permanent magnet along the radial direction of the rotor core is a, the maximum thickness of the permanent magnet along the circumferential direction is b, and the coefficient K satisfies:

[0006] wherein, , .

[0007] According to the motor of the first aspect of the utility model, the motor has at least the following beneficial effects: by optimizing and adjusting the minimum distance D2 between two permanent magnets arranged symmetrically about the central axis of the rotor core, the maximum length a of the permanent magnet along the radial direction and the maximum thickness b of the permanent magnet along the circumferential direction, the following conditions are met: , wherein, , N is the number of permanent magnets, under the premise of adapting to shafts of various diameter specifications, that is, the value of D2 is larger, by optimizing the maximum length a of the permanent magnet along the radial direction and the maximum thickness b along the circumferential direction, the cross-sectional area of the core unit, the cross-sectional area of the permanent magnet and the ratio of the two are adjusted, the magnetic field of the permanent magnet is increased, the magnetic flux saturation degree of the rotor core is reduced, the utilization rate of the permanent magnet and the rotor core is improved, thereby the output torque of the motor is increased, at the same time, the no-load back electromotive force is improved, and then the loss is reduced, and the operating efficiency of the motor is improved.

[0008] According to some embodiments of the utility model, the maximum thickness b of the permanent magnet along the circumferential direction satisfies: 5.5mm≤b≤9.5mm;And / or, the minimum distance D2 between the two permanent magnets arranged symmetrically about the center axis of the rotor core satisfies: 24mm≤D2≤33mm.

[0009] According to some embodiments of the utility model, the maximum outer diameter of the rotor core is D1, the outer end of the mounting groove is provided with a slot and the minimum width of the slot is W1, and it satisfies: 0.25≤N*W1 / (π*D1)≤0.4.

[0010] According to some embodiments of the utility model, the maximum outer diameter of the rotor core is D1, the minimum outer diameter of the stator core is D3, and it satisfies: 0.65≤D1 / D3≤0.75.

[0011] According to some embodiments of the utility model, the stator tooth includes a tooth part and a tooth shoe, the tooth part is connected to the inner peripheral wall of the stator yoke part and is arranged to extend towards the center of the stator core, the tooth shoe is connected to one end of the tooth part away from the stator yoke part and is arranged to protrude along the circumferential direction towards both sides of the tooth part, the minimum tooth width of the tooth part is W2, and it satisfies: 0.33≤2*W2 / (D3-D1)≤0.47.

[0012] According to some embodiments of the utility model, the stator tooth includes a tooth part and a tooth shoe, the tooth part is connected to the inner peripheral wall of the stator yoke part and is arranged to extend towards the center of the stator core, the tooth shoe is connected to one end of the tooth part away from the stator yoke part and is arranged to protrude along the circumferential direction towards both sides of the tooth part, the maximum distance of the two ends of the tooth shoe away from each other along the circumferential direction is W3, the maximum distance of the two ends of the core unit away from each other along the circumferential direction is W4, and it satisfies: 1.1≤W3 / W4≤1.3.

[0013] According to some embodiments of the present invention, the stator yoke includes a plurality of yoke units arranged sequentially along the circumference, at least one of the two adjacent yoke units is provided with a splicing structure, and the remaining two adjacent yoke units are connected by a bending portion, and the plurality of stator teeth are respectively connected to the plurality of yoke units.

[0014] According to some embodiments of the present invention, the rotor assembly further includes an inner core, which is disposed in the space surrounded by a plurality of core units, and the inner core is disconnected from the plurality of core units; and / or, two adjacent core units are disconnected from each other.

[0015] A fan according to a second aspect of the present invention includes a wind turbine and a motor according to a first aspect of the present invention. The rotor assembly includes a rotating shaft connected to the rotor core, and the wind turbine is mounted on the rotating shaft.

[0016] The fan according to the second aspect embodiment of the present invention has at least the following beneficial effects: Because the fan uses the aforementioned motor, by optimizing and adjusting the minimum distance D2 between two permanent magnets arranged symmetrically about the central axis of the rotor core, the maximum radial length a of the permanent magnets, and the maximum circumferential thickness b of the permanent magnets, the fan satisfies… ,in, , N represents the number of permanent magnets. Under the premise of adapting to various diameter shafts, i.e., the value of D2 is relatively large, by optimizing the maximum radial length a and the maximum circumferential thickness b of the permanent magnets, the cross-sectional area of ​​the core unit, the cross-sectional area of ​​the permanent magnets, and the ratio between the two are adjusted. This increases the magnetic field of the permanent magnets, while reducing the magnetic flux saturation of the rotor core, improving the utilization rate of the permanent magnets and the rotor core, thereby increasing the output torque of the motor. At the same time, it increases the no-load back EMF, thereby reducing losses and improving the operating efficiency of the motor.

[0017] The electrical equipment according to the third aspect of the present invention includes the fan according to the second aspect of the present invention.

[0018] The electrical device according to the third aspect embodiment of the present invention has at least the following beneficial effects: Because the electrical device uses the aforementioned fan, by optimizing and adjusting the minimum distance D2 between two permanent magnets arranged symmetrically about the central axis of the rotor core, the maximum radial length a of the permanent magnets, and the maximum circumferential thickness b of the permanent magnets, it satisfies… ,in, , N is the number of permanent magnets, under the premise of adapting to various diameter specifications of the rotating shaft, that is, the value of D2 is larger, by optimizing the maximum length a of the permanent magnet along the radial direction and the maximum thickness b along the circumferential direction, the cross-sectional area of the core unit, the cross-sectional area of the permanent magnet and the proportion of the two are adjusted, the magnetic field of the permanent magnet is increased, the magnetic flux saturation degree of the rotor core is reduced, the utilization rate of the permanent magnet and the rotor core is improved, so that the output torque of the motor is increased, at the same time, the no-load back electromotive force is improved, and then the loss is reduced, and the operation efficiency of the motor is improved.

[0019] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter in the description of the application. BRIEF DESCRIPTION OF DRAWINGS

[0020] The present application will be further described below in conjunction with the drawings and examples, wherein:

[0021] Figure 1 is a cross-sectional view of the motor (one of the permanent magnets is hidden) in the embodiment of the present application;

[0022] Figure 2 is a partial cross-sectional view of the rotor assembly in the embodiment of the present application;

[0023] Figure 3 is a partial cross-sectional view of the stator core and the core unit combination in the embodiment of the present application;

[0024] Figure 4 is a cross-sectional view of the permanent magnet in the embodiment of the present application;

[0025] Figure 5 is a curve graph of the no-load back electromotive force per unit value changing with K value and the operation efficiency of the motor changing with K value in the embodiment of the present application;

[0026] Figure 6 is a curve graph of the no-load back electromotive force per unit value changing with the value of N*W1 / (π*D1) in the embodiment of the present application;

[0027] Figure 7 is a surface graph of the efficiency of the motor changing with the value of D1 / D3 and the value of 2*W2 / (D3-D1) in the embodiment of the present application;

[0028] Figure 8 is a curve comparison graph of the output torque of the motor and the output torque of the motor of the prior art changing with input current respectively in the embodiment of the present application.

[0029] REFERENCE NUMERALS

[0030] Stator assembly 100; stator core 110; stator yoke 111; yoke unit 1111; splicing structure 1112; bending part 1113; stator tooth 112; tooth part 1121; tooth shoe 1122; winding slot 113;

[0031] Rotor assembly 200; rotor core 210; core unit 211; outer magnetic bridge 2111; inner magnetic bridge 2112; mounting groove 212; permanent magnet 220; first end face 221; second end face 222; inner core 230; air gap 240. DETAILED DESCRIPTION

[0032] The embodiments of the present application are described in detail below, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only, and are used only for explaining the present application, and cannot be understood as a limitation of the present application.

[0033] In the description of the present application, it should be understood that, in relation to the orientation description, for example, the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as a limitation of the present application.

[0034] In the description of the present application, the meaning of several is one or more, and the meaning of multiple is two or more, greater than, less than, more than, etc. are understood as not including the number, above, below, etc. are understood as including the number. If it is described as first, second, etc., it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0035] In the description of the present application, unless otherwise explicitly limited, the words such as setting, mounting, connecting, assembling, cooperating, etc. should be understood in a broad sense, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical scheme.

[0036] Referring to Figures 1 to 8 As shown in the drawings, the first aspect of the present application provides a motor applied to an electric appliance, which can be an air conditioner, a fresh air machine, etc. For example, the motor is applied to a fan of an air conditioner, as a power source of the fan, to meet the fan to realize the air supply function.

[0037] The structure of the motor is described in detail below.

[0038] Referring toFigure 1 As shown, it can be understood that the motor comprises a stator assembly 100 and a rotor assembly 200. Both the stator assembly 100 and the rotor assembly 200 are annular, and the stator assembly 100 is arranged around the outer periphery of the rotor assembly 200, and the inner periphery wall of the stator assembly 100 is arranged in spaced relation with the outer periphery wall of the rotor assembly 200 and forms an air gap 240. That is, the motor is of an inner rotor structure.

[0039] Referring to Figure 1 As shown, it can be understood that the stator assembly 100 comprises a stator core 110 and a plurality of windings. The stator core 110 is annular as a whole, and generally, the stator core 110 is composed of a plurality of stator laminations arranged in stacked relation along the direction of the central axis of the stator core 110. The stator core 110 comprises a stator yoke 111 and a plurality of stator teeth 112. The stator yoke 111 is annular, and the plurality of stator teeth 112 are each connected to the inner periphery wall of the stator yoke 111 and are each arranged in extending relation along the radial direction of the stator core 110 towards the central axis of the stator core 110, and the plurality of stator teeth 112 are arranged in equal intervals along the circumferential direction of the stator core 110. In this way, the space on the side of the plurality of stator teeth 112 close to the central axis of the stator core 110 forms the inner hole of the stator core 110. It can be easily understood that the direction of the central axis of the stator core 110 is the axial direction of the stator core 110, the direction around the central axis of the stator core 110 is the circumferential direction of the stator core 110, and the direction perpendicular to the central axis of the stator core 110 and pointing outward from the central axis of the stator core 110 and its reverse direction are the radial direction of the stator core 110. Along the radial direction of the stator core 110, the side close to the central axis of the stator core 110 is the inner side, and the side away from the central axis of the stator core 110 is the outer side.

[0040] Referring to Figure 1 As shown, it can be understood that the winding slot 113 is defined between two adjacent stator teeth 112, and the number of winding slots 113 is equal to the number of stator teeth 112, and the number of winding slots 113 and the number of stator teeth 112 are both equal to the number of windings. The plurality of windings are each arranged on the plurality of stator teeth 112, and each winding is accommodated in the winding slots 113 on both sides of the corresponding stator tooth 112.

[0041] Referring to Figure 1As shown, it can be understood that the stator assembly 100 is arranged around the outer periphery of the rotor assembly 200, i.e. the rotor assembly 200 is arranged in the inner hole of the stator core, and the rotor assembly 200 can rotate relative to the stator assembly 100. Specifically, the rotor assembly 200 includes a rotor core 210 and a plurality of permanent magnets 220, wherein the rotor core 210 is composed of a plurality of core units 211, the outer contour of the core unit 211 is substantially fan-shaped, and the small end of the fan-shaped core unit 211 is closer to the central axis of the stator core 110 than the large end. The plurality of core units 211 are arranged at equal intervals along the circumference of the stator core 110, and the installation slot 212 is defined between the adjacent two core units 211, the number of installation slots 212 is equal to the number of core units 211, and the number of installation slots 212 and the number of core units 211 are equal to the number of permanent magnets 220. The plurality of permanent magnets 220 are respectively installed in the plurality of installation slots 212.

[0042] Referring to Figure 1 As shown, it can be understood that in the present example, the motor is twelve-slot ten-pole, i.e. the number of winding slots 113 is twelve, and the number of permanent magnets 220 is ten.

[0043] Of course, the slot-pole number of the motor is not limited to twelve-slot ten-pole, but can also be other slot-pole combinations, which will not be described here.

[0044] Referring to Figure 1 As shown, define the number of permanent magnets 220 as N, and N is an even number. The plurality of permanent magnets 220 are arranged at equal intervals along the circumference of the rotor core 210. Therefore, there are two permanent magnets 220 arranged symmetrically about the central axis of the rotor core 210, i.e. the two permanent magnets 220 are arranged opposite to each other along the radial direction of the rotor core 210.

[0045] Define the minimum distance D2 of the two permanent magnets 220 arranged symmetrically about the central axis of the rotor core 210. When measuring D2, the minimum distance between the two end faces of the two permanent magnets 220 arranged symmetrically about the central axis of the rotor core 210 facing the central axis of the rotor core 210 can be directly measured, and the two end faces are usually parallel. It is easy to understand that D2 reflects the size of the space surrounded by the plurality of core units 211 to some extent, i.e. reflects the diameter size of the shaft that can be installed. The larger D2 is, the larger the diameter of the shaft that can be installed is, and vice versa.

[0046] Referring to Figure 4As shown, the maximum length of the permanent magnet 220 along the radial direction of the rotor core 210 is defined as a, that is, the maximum distance between the two wall surfaces of the permanent magnet 220 facing away from each other along the radial direction of the rotor core 210, and the maximum thickness of the permanent magnet 220 along the circumferential direction of the rotor core 210 is defined as b, that is, the maximum distance between the two wall surfaces of the permanent magnet 220 facing away from each other along the circumferential direction of the rotor core 210. Generally, the projection of the permanent magnet 220 on the projection plane perpendicular to the central axis of the rotor core 210 is a rectangle, that is, the length of the projection of the permanent magnet 220 is a, and the width of the projection of the permanent magnet 220 is b.

[0047] Referring to Figure 1 and Figure 4 As shown, it can be understood that the number N of the permanent magnets 220, the minimum distance D2 between the two permanent magnets 220 arranged centrally symmetrically about the central axis of the rotor core 210, the maximum length a of the permanent magnet 220 along the radial direction of the rotor core 210, the maximum thickness b of the permanent magnet 220 along the circumferential direction of the rotor core 210, and the coefficient K satisfy:

[0048] wherein, , .

[0049] Referring to Figure 2 As shown, it can be understood that the two end surfaces of the permanent magnet 220 facing away from each other along the radial direction of the rotor core 210 are defined as a first end surface 221 and a second end surface 222, respectively, wherein the first end surface 221 is closer to the central axis of the rotor core 210 than the second end surface 222. The core unit 211 has a first central line Z1 intersecting and perpendicular to the central axis of the rotor core 210, and the permanent magnet 220 has a second central line Z2 intersecting and perpendicular to the central axis of the rotor core 210, and the second central line Z2 is perpendicular to the first end surface 221 and the second end surface 222.

[0050] Referring to Figure 2 As shown, it can be understood that, in the projection plane perpendicular to the central axis of the rotor core 210, among the adjacent core unit 211 and the permanent magnet 220, the included angle between the line connecting the projection of the end of the second end surface 222 close to the first central line Z1 and the projection of the central axis of the rotor core 210 and the second central line Z2 is θ1, and the vertical distance from the end of the projection of the second end surface 222 close to the first central line Z1 to the first central line Z1 is L1. The included angle between the line connecting the projection of the end of the first end surface 221 close to the first central line Z1 and the projection of the central axis of the rotor core 210 and the second central line Z2 is θ2, and the vertical distance from the end of the projection of the first end surface 221 close to the first central line Z1 to the first central line Z1 is L2.

[0051] It is easy to understand that, generally speaking, the end of the projection of the second end surface 222 close to the first center line Z1 is located on the projection of the wall surface on the side of the iron core unit 211 facing the permanent magnet 220, and similarly, the end of the projection of the first end surface 221 close to the first center line Z1 is located on the projection of the wall surface on the side of the iron core unit 211 facing the permanent magnet 220. Therefore, L1 reflects the size of the outer end of the iron core unit 211 in the circumferential direction of the rotor core 210 to some extent, and L2 reflects the size of the inner end of the iron core unit 211 in the circumferential direction of the rotor core 210 to some extent.

[0052] Referring to Figure 2 According to the Pythagorean theorem, it can be obtained that , wherein, .

[0053] Similarly,

[0054] wherein, .

[0055] Therefore,

[0056] .

[0057] That is, 9.5≤K=L1 / L2≤22. Therefore, the coefficient K reflects the ratio of the sizes of the outer end and the inner end of the iron core unit 211 in the circumferential direction of the rotor core 210 to some extent. Generally speaking, L2 is small, and the value of L2 can be regarded as a fixed value, and the coefficient K also reflects the space occupied by the iron core unit 211 in the circumferential direction of the rotor core 210 or the amount of material of the iron core unit 211 to some extent.

[0058] It is easy to understand that the space of the rotor assembly 200 in the circumferential direction of the rotor core 210 is occupied by the iron core unit 211 and the permanent magnet 220. Under the premise that the maximum outer diameter and the minimum inner diameter of the rotor core 210 are constant, the larger the space occupied by the iron core unit 211 in the circumferential direction of the rotor core 210, that is, the more the amount of the iron core unit 211, the smaller the space occupied by the permanent magnet 220 in the circumferential direction of the rotor core 210, that is, the less the amount of the permanent magnet 220, and vice versa.

[0059] It is easy to understand that the no-load back EMF is positively correlated with the number of turns of the winding and the magnetic flux of the permanent magnet 220.

[0060] When K < 9.5, under the premise that the value of L2 and the maximum outer diameter of the rotor core 210 are constant, L1 is too small, that is, the size of the outer end of the core unit 211 in the circumferential direction of the rotor core 210 is too small, the cross-sectional area and the amount of the core unit 211 are reduced, the magnetic flux of the core unit 211 is prone to saturation, although the cross-sectional area and the amount of the permanent magnet 220 are increased, the utilization rate is reduced.

[0061] When K > 22, under the premise that the value of L2 and the maximum outer diameter of the rotor core 210 are constant, L1 is too large, that is, the size of the outer end of the core unit 211 in the circumferential direction of the rotor core 210 is too large, resulting in a decrease in the cross-sectional area and the amount of the permanent magnet 220, a decrease in the output torque of the motor, a decrease in the no-load back EMF, although the cross-sectional area and the amount of the core unit 211 are increased, the utilization rate is reduced, and the iron loss is increased.

[0062] Therefore, 9.5 ≤ K ≤ 22, for example, the value of K is 9.5, 11, 13.4, 14, 15.6, 17.1, 18, 19, 21.5 or 22, etc., under the premise of adapting to various diameter specifications of the rotating shaft, even if D2 is large, by optimizing the maximum length a and the maximum thickness b of the permanent magnet 220, adjusting the amount of the core unit 211, and synchronously adjusting the amount of the permanent magnet 220 and the proportion of the amount of the core unit 211 and the permanent magnet 220, the amount of the core unit 211 and the permanent magnet 220 is within a suitable range, thereby increasing the magnetic field of the permanent magnet 220, reducing the saturation degree of the magnetic flux of the core unit 211, improving the utilization rate of the permanent magnet 220 and the rotor core 210, thereby increasing the output torque of the motor, improving the no-load back EMF, achieving an increase of about 32% in the no-load back EMF, reducing the loss, and improving the operating efficiency of the motor.

[0063] It is easy to understand that the output torque of the motor is positively correlated with the product of the no-load back EMF and the input current.

[0064] Under the premise that the output torque of the motor is constant, the no-load back EMF is improved, therefore, the input current can be reduced, thereby reducing the loss, and further improving the operating efficiency of the motor, thereby improving the output performance of the motor.

[0065] Reference Figure 5As shown in the figure, the curves of the unit value of the no-load back EMF and the curves of the operation efficiency of the motor with the change of K value are shown. The unit value of the no-load back EMF is the relative value under the benchmark that the no-load back EMF of the prior art is 1. As can be seen from the two curves, with the increase of K value, the unit value of the no-load back EMF and the operation efficiency of the motor both first increase and then decrease, and when the value of K is about 17.5, the unit value of the no-load back EMF and the operation efficiency of the motor both reach the maximum value. When 9.5≤K≤22, the unit value of the no-load back EMF and the operation efficiency of the motor are both relatively large, wherein the unit value of the no-load back EMF is about 1.05-1.3, and the operation efficiency of the motor is about 68%-73.5%. That is to say, when 9.5≤K≤22, the no-load back EMF and the operation efficiency of the motor can be effectively improved.

[0066] Referring to Figure 1 As shown in the figure, it can be understood that the minimum distance D2 of the two permanent magnets 220 arranged symmetrically about the center axis of the rotor core 210 satisfies 24mm≤D2≤33mm. For example, D2 is 24mm, 26mm, 29mm, 30.5mm, 31mm, 32.7mm or 33mm, etc., which makes D2 larger under the premise that the maximum outer diameter of the rotor core 210 is constant, so as to increase the shaft hole of the rotor assembly 200, thereby being able to adapt to various diameter specifications of the rotating shaft, good universality, and being conducive to reducing development cost.

[0067] Referring to Figure 4 As shown in the figure, it can be understood that the maximum thickness b of the permanent magnet 220 along the circumferential direction of the rotor core 210 satisfies 5.5mm≤b≤9.5mm. For example, b is 5.5mm, 6mm, 6.8mm, 7.2mm, 8mm, 8.9mm or 9.5mm, etc., which makes the maximum thickness of the permanent magnet 220 larger, so as to increase the magnetic field of the permanent magnet 220, which is conducive to improving the output torque of the motor and increasing the no-load back EMF.

[0068] In this embodiment, 24mm≤D2≤33mm and 5.5mm≤b≤9.5mm are simultaneously satisfied, which can increase the amount of the permanent magnet 220 under the premise of adapting to various diameter specifications of the rotating shaft, increase the magnetic field of the permanent magnet 220, thereby effectively ensuring the output torque of the motor, increasing the no-load back EMF, and realizing the improvement of the output performance of the motor.

[0069] It is easy to understand that, due to the increase of the amount of the permanent magnet 220, the magnetic field stability of the permanent magnet 220 is high, the anti-demagnetization ability is enhanced, the demagnetization current required for the demagnetization of the permanent magnet 220 is larger, the demagnetization current is improved by about 30%, and the demagnetization performance of the motor is improved.

[0070] Referring to Figure 1As shown, it can be understood that the two adjacent core units 211 are disconnected from each other, which is conducive to reducing the magnetic leakage and improving the utilization rate of the permanent magnet 220.

[0071] Referring to Figure 1 As shown, it can be understood that the two adjacent core units 211 define a mounting groove 212, and an outer end (i.e., an end away from the rotor core 210) of the mounting groove 212 is provided with a notch. The minimum width of the notch is defined as W1, and the minimum width W1 of the notch is the minimum distance between the outer ends of the opposite sides of the two core units 211 located on both sides of the mounting groove 212 along the circumferential direction of the rotor core 210.

[0072] Referring to Figure 1 As shown, it can be understood that in this embodiment, the core unit 211 includes two outer magnetic bridges 2111 and two inner magnetic bridges 2112. The two outer magnetic bridges 2111 are located on both sides of the outer end of the core unit 211 along the circumferential direction of the rotor core 210, and the two inner magnetic bridges 2112 are located on both sides of the inner end of the core unit 211 along the circumferential direction of the rotor core 210. The outer magnetic bridge 2111 and the inner magnetic bridge 2112 respectively abut the two ends of the permanent magnet 220 along the radial direction to achieve positioning of the permanent magnet 220. The minimum width W1 of the notch is the minimum distance between the two outer magnetic bridges 2111 located at the outer end of the mounting groove 212 and arranged opposite to each other in the circumferential direction of the rotor core 210.

[0073] Referring to Figure 1 As shown, the maximum outer diameter of the rotor core 210 is defined as D1, and the number of core units 211 in this embodiment is an even number. In the projection plane perpendicular to the central axis of the rotor core 210, the maximum outer diameter D1 of the rotor core 210 is the maximum distance of the line segment extending from the center of the rotor core 210 (i.e., the projection of the central axis) to the projection of the outer wall surface of the two core units 211 arranged symmetrically about the central axis of the rotor core 210. That is, the maximum outer diameter D1 of the rotor core 210 is the maximum value of the outer diameters of the rotor core 210 at different positions.

[0074] Referring to Figure 1As shown, it can be understood that the minimum width W1 of the slot and the maximum outer diameter D1 of the rotor core 210 satisfy: 0.25≤N*W1 / (π*D1)≤0.4. Wherein, under the premise that the size of the outer magnetic bridge 2111 is certain, W1 can reflect the width of the mounting groove 212 along the circumference of the rotor core 210 to a certain extent, and the width of the mounting groove 212 matches the maximum thickness b of the permanent magnet 220. That is, W1 reflects the space occupied by the permanent magnet 220 in the circumference of the rotor core 210 to a certain extent, the larger W1 is, the larger the space occupied by the permanent magnet 220 in the circumference of the rotor core 210 is, and the larger the amount of the permanent magnet 220 is. Correspondingly, the space occupied by the core unit 211 in the circumference of the rotor core 210 is smaller, that is, the amount of the core unit 211 is small. N*W1 reflects the space occupied by N permanent magnets 220 in the circumference of the rotor core 210 to a certain extent.

[0075] π*D1 is the circumference of a circle with the maximum outer diameter of the rotor core 210 as the diameter. Generally speaking, after the minimum inner diameter of the stator core 110 and the distance of the air gap 240 in the radial direction of the stator core 110 are determined, the maximum outer diameter D1 of the rotor core 210 can be determined, that is, the space of the rotor assembly 200 in the circumference of the rotor core 210 can be determined.

[0076] When N*W1 / (π*D1)<0.25, based on D2 determination, and the maximum outer diameter D1 of the rotor core 210 is determined, the minimum width of the slot is too small, the maximum thickness of the permanent magnet 220 is too small, the amount of the permanent magnet 220 is reduced, the magnetic field of the permanent magnet 220 is weakened, resulting in a decrease in the output torque of the motor and a decrease in the no-load back electromotive force, and the amount of the core unit 211 is increased. Limited by the magnetic field of the permanent magnet 220, the utilization rate of the core unit 211 is reduced, the iron loss is increased, and the operating efficiency of the motor is reduced.

[0077] When N*W1 / (π*D1)>0.4, based on D2 determination, and the maximum outer diameter D1 of the rotor core 210 is determined, the minimum width of the slot is too large, the maximum thickness of the permanent magnet 220 is too large, although the amount of the permanent magnet 220 is increased, the magnetic field of the permanent magnet 220 is enhanced, but the amount of the core unit 211 is reduced, the magnetic flux of the core unit 211 is easy to saturate, resulting in a decrease in the utilization rate of the permanent magnet 220, which will also result in a decrease in the output torque of the motor and a decrease in the no-load back electromotive force, and a decrease in the operating efficiency.

[0078] Therefore, 0.25≤N*W1 / (π*D1)≤0.4 is made, for example, the value of N*W1 / (π*D1) is 0.25, 0.28, 0.31, 0.36, 0.39 or 0.4, etc., is determined based on D2, and the maximum outer diameter D1 of the rotor core 210 is determined, the use of the permanent magnet 220 and the core unit 211 is optimized by optimizing the minimum width of the slot, the magnetic field of the permanent magnet 220 is enhanced, the no-load back EMF is improved, the magnetic flux saturation degree of the core unit 211 is reduced, and the utilization rate of the core unit 211 and the permanent magnet 220 is improved, the iron loss is reduced, and thus the output torque and operating efficiency of the motor are improved.

[0079] Referring to Figure 6 As shown in the figure, the curve showing the change of the no-load back EMF in per unit with the value of N*W1 / (π*D1) is shown. As can be seen from the curve in the figure, as the value of N*W1 / (π*D1) increases, the no-load back EMF in per unit first increases and then decreases, and when the value of N*W1 / (π*D1) is about 0.325, the no-load back EMF in per unit is maximum, about 1.2. It is easy to understand that when 0.25≤N*W1 / (π*D1)≤0.4, the no-load back EMF in per unit is in the range of about 1.05 to 1.2. As can be seen, 0.25≤N*W1 / (π*D1)≤0.4 can effectively improve the no-load back EMF, thereby improving the operating efficiency of the motor.

[0080] Referring to Figure 1 As shown in the figure, the minimum outer diameter of the stator core 110 is defined as D3. In this embodiment, the outer contour of the stator core 110 is a regular polygon, the number of sides is equal to the number of winding slots 113, and is an even number. In the projection plane perpendicular to the central axis of the stator core 110, the minimum outer diameter D3 of the stator core 110 is the distance between the two line segments of the outer contour of the stator core 110 which are symmetrically arranged about the center axis of the stator core 110. That is, the minimum outer diameter D3 of the stator core 110 is the minimum value among the outer diameters at all positions of the stator core 110.

[0081] Referring to Figure 1 As shown in the figure, it can be understood that the maximum outer diameter D1 of the rotor core 210 and the minimum outer diameter D3 of the stator core 110 satisfy: 0.65≤D1 / D3≤0.75.

[0082] It is easy to understand that, under the premise that the distance of the air gap 240 along the radial direction of the stator core 110 is constant, to a certain extent, reflects the thickness dimension of the stator core 110 in the radial direction.

[0083] When D1 / D3<0.65, the value of D3-D1 is too large, the thickness dimension of the stator core 110 in the radial direction is increased, the amount of the stator core 110 and the number of turns of the winding are increased, and the cost is increased; under the premise that the minimum outer diameter of the stator core 110 is constant, the space of the rotor core 210 is compressed, the thickness dimension of the rotor core 210 in the radial direction is reduced, the amount of the rotor core 210 and the amount of the permanent magnet 220 are reduced, the magnetic flux of the rotor core 210 is prone to saturation, and the magnetic flux of the permanent magnet 220 is too small, although the number of turns of the winding is increased, the utilization rate of the winding and the utilization rate of the stator core 110 are reduced, the iron loss and the copper loss are increased, thereby causing the no-load back EMF of the motor to be too small, the output torque of the motor to be reduced, and the efficiency to be reduced.

[0084] When D1 / D3>0.75, the value of D3-D1 is too small, the thickness dimension of the stator core 110 in the radial direction is reduced, the amount of the stator core 110 and the number of turns of the winding are reduced, and the magnetic flux of the stator core 110 is prone to saturation; under the premise that the minimum outer diameter of the stator core 110 is constant, the thickness dimension of the rotor core 210 in the radial direction is increased, the amount of the rotor core 210 and the amount of the permanent magnet 220 are increased, and the cost is increased, although the magnetic flux of the permanent magnet 220 is increased, the utilization rate of the permanent magnet 220 and the utilization rate of the rotor core 210 are reduced, the iron loss and the copper loss are increased, thereby causing the no-load back EMF of the motor to be too small, the output torque of the motor to be reduced, and the efficiency to be reduced.

[0085] Therefore, 0.65≤D1 / D3≤0.75, for example, the value of D1 / D3 is 0.65, 0.68, 0.69, 0.72, 0.73, or 0.75, etc., the maximum outer diameter D1 of the rotor core 210 and the minimum outer diameter D3 of the stator core 110 are optimized and adjusted, the thickness dimension of the stator core 110 in the radial direction, the thickness dimension of the rotor core 210 in the radial direction, the number of turns of the winding, and the amount of the permanent magnet 220 are within a reasonable range, the saturation degree of the magnetic flux of the stator core 110 and the rotor core 210 is reduced, the utilization rate of the winding and the permanent magnet 220 is improved, the iron loss and the copper loss are reduced, thereby ensuring the output torque of the motor, improving the no-load back EMF of the motor, reducing the amount of materials, reducing the cost, reducing the cost by about 20%, and effectively improving the operating efficiency of the motor.

[0086] Referring to Figure 3 As shown in FIG. 1, it can be understood that the stator tooth 112 includes a tooth portion 1121 and a tooth shoe 1122, wherein the tooth portion 1121 is connected to the inner circumferential wall of the stator yoke portion 111 and is arranged to extend in the radial direction towards the center of the stator core 110, and the tooth shoe 1122 is connected to one end of the tooth portion 1121 away from the stator yoke portion 111 and is arranged to protrude along the circumferential direction of the stator core 110 towards both sides of the tooth portion 1121.

[0087] Referring toFigure 3 As shown in FIG. 12, it can be understood that the minimum tooth width of the tooth portion 1121 is defined as W2. W2 is the minimum distance between two wall surfaces of the tooth portion 1121 facing away from each other in the circumferential direction of the stator core 110, and generally, the two wall surfaces of the tooth portion 1121 facing away from each other in the circumferential direction of the stator core 110 are parallel.

[0088] Referring to FIG. 13, Figure 1 and Figure 3 As shown in FIG. 13, it can be understood that the minimum tooth width W2 of the tooth portion 1121, the maximum outer diameter D1 of the rotor core 210, and the minimum outer diameter D3 of the stator core 110 satisfy: 0.33≤2*W2 / (D3-D1)≤0.47. That is, the ratio of the minimum tooth width of the tooth portion 1121 to the thickness dimension of the stator core 110 in the radial direction is limited.

[0089] Under the premise of satisfying 0.65≤D1 / D3≤0.75, it can be considered that the value of D3-D1 is determined, when 2*W2 / (D3-D1)<0.33, the minimum tooth width of the tooth portion 1121 is too small, the magnetic flux of the tooth portion 1121 is prone to saturation, resulting in a decrease in the utilization rate of the magnetic field, and a decrease in the output torque and operating efficiency of the motor; when 2*W2 / (D3-D1)>0.47, the minimum tooth width of the tooth portion 1121 is too large, the cross-sectional area of the winding slot 113 is reduced, resulting in a decrease in the number of turns of the winding, which will also cause the output torque of the motor to decrease, and the no-load back electromotive force to decrease, and the efficiency to decrease.

[0090] Therefore, 0.33≤2*W2 / (D3-D1)≤0.47, for example, the value of 2*W2 / (D3-D1) is 0.33, 0.38, 0.4, 0.42, 0.45 or 0.47, etc., can further optimize the minimum tooth width of the tooth portion 1121, to reduce the degree of magnetic flux saturation of the tooth portion 1121, and ensure the number of turns of the winding, thereby ensuring the output torque of the motor, and improving the no-load back electromotive force, and improving the operating efficiency of the motor.

[0091] Referring to FIG. 14, Figure 7As shown in the figure, the figure shows the surface graph of the efficiency of the motor varying with the value of D1 / D3 and the value of 2*W2 / (D3-D1). It can be seen from the figure that when the value of D1 / D3 is constant, the efficiency of the motor first increases and then decreases with the increase of the value of 2*W2 / (D3-D1), and when the value of 2*W2 / (D3-D1) is constant, the efficiency of the motor also first increases and then decreases with the increase of the value of D1 / D3. And when the value of D1 / D3 is about 0.72 and the value of 2*W2 / (D3-D1) is about 0.43, the efficiency of the motor is maximum, about 73%. When 0.65≤D1 / D3≤0.75 and 0.33≤2*W2 / (D3-D1)≤0.47, the efficiency of the motor remains above about 66.5%. Therefore, when 0.65≤D1 / D3≤0.75 and 0.33≤2*W2 / (D3-D1)≤0.47, the efficiency of the motor can be effectively improved.

[0092] Referring to Figure 3 As shown in the figure, it can be understood that the maximum distance of the two ends of the toothed shoe 1122 away from the circumferential direction of the stator core 110 is W3, and the maximum distance of the two ends of the core unit 211 away from the circumferential direction of the rotor core 210 is W4. In this embodiment, the maximum distance W4 of the two ends of the core unit 211 away from the circumferential direction of the rotor core 210 is the maximum distance of the two ends of the two outer magnetic bridges 2111 away from the circumferential direction of the rotor core 210.

[0093] In other embodiments, on the premise that the two adjacent core units 211 are disconnected, and there is no outer magnetic bridge 2111 on both sides of the outer end of the core unit 211 along the circumferential direction of the rotor core 210, then the maximum distance W4 of the two ends of the core unit 211 away from the circumferential direction of the rotor core 210 is the maximum distance of the two walls of the core unit 211 away from the circumferential direction of the rotor core 210. Or only one side is provided with an outer magnetic bridge 2111, then the maximum distance W4 of the two ends of the core unit 211 away from the circumferential direction of the rotor core 210 is the maximum distance between the outer magnetic bridge 2111 and the other walls.

[0094] Referring to Figure 3 As shown in the figure, it can be understood that the maximum distance W3 of the two ends of the toothed shoe 1122 away from the circumferential direction of the stator core 110 and the maximum distance W4 of the two ends of the core unit 211 away from the circumferential direction of the rotor core 210 satisfy: 1.1≤W3 / W4≤1.3.

[0095] It is easy to understand that the magnetic lines of the magnetic field between the stator assembly 100 and the rotor assembly 200 are mainly conducted through the toothed shoe 1122 and the core unit 211, the maximum distance W3 between the two ends of the toothed shoe 1122 along the circumferential direction of the stator core 110 reflects the ability of the toothed shoe 1122 to receive or emit the magnetic lines to some extent, the greater the value of W3, the better the ability of the toothed shoe 1122 to receive or emit the magnetic lines, and under the premise of a certain magnetic field intensity, the lower the magnetic flux saturation degree of the toothed shoe 1122. Similarly, the maximum distance W4 between the two ends of the core unit 211 along the circumferential direction of the rotor core 210 reflects the ability of the core unit 211 to receive or emit the magnetic lines to some extent, the greater the value of W4, the better the ability of the core unit 211 to receive or emit the magnetic lines, and under the premise of a certain magnetic field intensity, the lower the magnetic flux saturation degree of the core unit 211.

[0096] When W3 / W4<1.1, the maximum distance W3 between the two ends of the toothed shoe 1122 along the circumferential direction of the stator core 110 is too small, the magnetic flux of the toothed shoe 1122 is easy to saturate, the utilization rate of the magnetic field is reduced, and the output torque of the motor is reduced; and the maximum distance W4 between the two ends of the core unit 211 along the circumferential direction of the rotor core 210 is too large, which is limited by the toothed shoe 1122, the utilization rate of the core unit 211 is reduced, the iron loss is increased, and the cost is increased.

[0097] When W3 / W4>1.3, the maximum distance W4 between the two ends of the core unit 211 along the circumferential direction of the rotor core 210 is too small, the magnetic flux of the core unit 211 is easy to saturate, the utilization rate of the magnetic field is reduced, and the output torque of the motor is reduced; and the maximum distance W3 between the two ends of the toothed shoe 1122 along the circumferential direction of the stator core 110 is too large, which is limited by the core unit 211, the utilization rate of the toothed shoe 1122 is reduced, the iron loss is increased, and the cost is increased.

[0098] It is easy to understand that the permanent magnet 220 is installed between the two adjacent core units 211, the permanent magnet 220 has a certain thickness along the circumferential direction of the rotor core 210, and in order to reduce the magnetic leakage, the two adjacent core units 211 are disconnected and the distance therebetween is as large as possible (less than the thickness of the permanent magnet 220). The slot opening of the wire slot 113 formed between the two adjacent toothed shoes 1122 is too large, which will cause the increase of the cogging torque, the vibration and the noise deterioration. Although the number of the toothed shoes 1122 is greater than the number of the core units 211, in the embodiment, the number of the toothed shoes 1122 is twelve and the number of the core units 211 is ten, which is limited by the installation of the permanent magnet 220, in order to reduce the magnetic leakage and the cogging torque, generally, W3>W4, and W3 / W4≥1.1.

[0099] Therefore, by setting 1.1≤W3 / W4≤1.3, for example, the value of W3 / W4 is 1.1, 1.15, 1.2, 1.28 or 1.3, etc., the maximum distance W3 of the toothed shoe 1122 along the circumferential direction of the two ends of the stator core 110 and the maximum distance W4 of the core unit 211 along the circumferential direction of the two ends of the rotor core 210 are optimized, while reducing the magnetic flux saturation degree of the toothed shoe 1122 and the core unit 211, improving the utilization rate of the magnetic field, reducing the iron loss, thereby improving the output torque and operating efficiency of the motor, and reducing the cost.

[0100] In other embodiments, the outer contour of the stator core 110 can also be a similar polygon (the outer contour is provided with a recess), a circle, a closed loop connected by a plurality of arc segments, etc.

[0101] It can be understood that the stator punching sheet constituting the stator core 110 is punched and processed from a sheet material such as a silicon steel plate. The shape of the stator punching sheet punched can be annular, and only a plurality of annular stator punching sheets need to be correspondingly stacked along the thickness direction to obtain the annular stator core 110. Alternatively, the shape of the stator punching sheet punched can be chain-shaped, and a plurality of chain-shaped stator punching sheets are correspondingly stacked along the thickness direction to obtain a chain structure, and then the chain structure is bent into a ring shape and butt-jointed at the head and tail, so as to obtain the annular stator core 110.

[0102] Referring to Figure 1 It can be understood that in the present embodiment, the stator punching sheet punched is chain-shaped. Therefore, when the material is arranged, the chain-shaped stator punching sheet is arranged in a straight line on the sheet material such as a silicon steel plate, so as to optimize the layout of the material, reduce waste, improve the material utilization rate of the sheet material, and thus reduce the material cost.

[0103] Continuing to refer to Figure 1 Specifically, in the stator core 110 composed of the chain-shaped stator punching sheet, the stator yoke portion 111 includes a plurality of yoke units 1111, the number of the yoke units 1111 is equal to the number of the stator teeth 112, and the plurality of yoke units 1111 are arranged in sequence along the circumferential direction of the stator core 110 and form an annular shape. The plurality of stator teeth 112 are respectively connected to the wall surface of the plurality of yoke units 1111 on the side of the central axis of the stator core 110.

[0104] Referring to Figure 1 and Figure 3It can be understood that at least one joint structure 1112 is arranged between two adjacent yoke units 1111, and a bending part 1113 is connected between each of the remaining two adjacent yoke units 1111. Specifically, in this embodiment, the stator core 110 is composed of a chain structure, and after the chain structure is assembled into a ring shape, the first and last two yoke units 1111 are connected through the joint structure 1112. The joint structure 1112 can be a dovetail groove structure, a concave-convex matching structure, etc. A bending part 1113 is connected between each of the remaining two adjacent yoke units 1111, and the bending part 1113 allows the two adjacent yoke units 1111 to be bent relative to each other in a direction perpendicular to the central axis of the stator core, so that the chain structure can be bent into a ring-shaped stator core 110, facilitating production.

[0105] Of course, the stator core 110 is composed of a plurality of chain structures which are sequentially connected into a ring shape, and the adjacent two chain structures are connected through the joint structure 1112. In each chain structure, a bending part 1113 is connected between each of the two adjacent yoke units 1111, which will not be described here.

[0106] Referring to Figure 1 It can be understood that in this embodiment, the rotor assembly 200 further includes an inner core 230, which is arranged in the space surrounded by the plurality of core units 211. Generally, the inner core 230 has an axis hole in the middle for the rotation shaft to pass through, and the rotation shaft is fixedly connected with the inner core 230. The inner core 230 and the plurality of core units 211 are disconnected from each other, which is conducive to further reducing the magnetic leakage and improving the utilization rate of the permanent magnets 220. It can be easily understood that the plurality of core units 211, the plurality of permanent magnets 220, the inner core 230 and the rotation shaft are filled with an injection body to achieve mutual connection and fixation, thereby improving the structural stability of the rotor assembly 200.

[0107] Referring to Figure 8 It can be understood that the figure shows a comparison diagram of the output torque of the motor of the embodiment and the output torque of the motor of the prior art with the change of the input current. As can be seen from the two curves, in the light load state, that is, when the input current is small, specifically, when the input current is in the range of 0A-0.6A, the two curves are basically coincident; in the heavy load state, that is, when the input current is large, specifically, when the input current is in the range of 0.6A-1.6A, the curve of the embodiment is above the curve of the prior art. That is, in the light load state, the output torque of the motor of the embodiment is basically equal to the output torque of the motor of the prior art, while in the heavy load state, the output torque of the motor of the embodiment is greater than the output torque of the motor of the prior art. The motor of the embodiment has good heavy load capacity, which improves the overload capacity to a certain extent.

[0108] The fan of the second aspect embodiment of the utility model, including wind wheel and the motor of the first aspect embodiment of the utility model, wind wheel fixed connection in the pivot.

[0109] The fan has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments.

[0110] The electric appliance of the third aspect embodiment of the utility model, including the fan of the second aspect embodiment of the utility model, the electric appliance can be air conditioner, new fan and the like.

[0111] The electric appliance has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments.

[0112] The above-mentioned embodiments of the utility model are described in detail in combination with the drawings, but the utility model is not limited to the above-mentioned embodiments, and various changes can be made within the knowledge range possessed by the ordinary skilled in the art without departing from the purpose of the utility model.

Claims

1. An electric machine characterized in that, The application relates to a motor, comprising: a stator assembly, comprising a stator core and a plurality of windings, the stator core being annular and provided with an inner hole, the stator core comprising a stator yoke and a plurality of stator teeth, the plurality of stator teeth being connected to the inner circumferential wall of the stator yoke and being arranged along the circumferential direction of the stator core, and the plurality of windings being respectively wound around the plurality of stator teeth; a rotor assembly, rotatably arranged in the inner hole, the rotor assembly comprising a rotor core and a plurality of permanent magnets, the rotor core comprising a plurality of core units arranged along the circumferential direction, and an installation groove being defined between two adjacent core units, and the plurality of permanent magnets being correspondingly arranged in the plurality of installation grooves; wherein the number of permanent magnets is N, N is an even number, the minimum distance between two permanent magnets arranged symmetrically about the central axis of the rotor core is D2, the maximum length of the permanent magnet along the radial direction of the rotor core is a, the maximum thickness of the permanent magnet along the circumferential direction is b, and the coefficient K satisfies: wherein , .

2. The electric machine of claim 1, wherein: the maximum thickness b of the permanent magnet along the circumferential direction satisfies 5.5mm<=b<=9.5mm; and / or the minimum distance D2 between two permanent magnets arranged symmetrically about the central axis of the rotor core satisfies 24mm<=D2<=33mm.

3. The electric machine of claim 1, wherein: the maximum outer diameter of the rotor core is D1, the outer end of the installation groove is provided with a slot, and the minimum width of the slot is W1, and 0.25<=N*W1 / (pi*D1)<=0.4 is satisfied.

4. The electric machine of claim 1, wherein: the maximum outer diameter of the rotor core is D1, and the minimum outer diameter of the stator core is D3, and 0.65<=D1 / D3<=0.75 is satisfied.

5. The electric machine of claim 4, wherein: the stator tooth comprises a tooth portion and a tooth shoe, the tooth portion is connected to the inner circumferential wall of the stator yoke and is arranged to extend towards the center of the stator core, the tooth shoe is connected to one end of the tooth portion away from the stator yoke and is arranged to protrude along the circumferential direction towards both sides of the tooth portion, and the minimum tooth width of the tooth portion satisfies 0.33<=2*W2 / (D3-D1)<=0.

47.

6. The electric machine of claim 1, wherein: the stator tooth comprises a tooth portion and a tooth shoe, the tooth portion is connected to the inner circumferential wall of the stator yoke and is arranged to extend towards the center of the stator core, the tooth shoe is connected to one end of the tooth portion away from the stator yoke and is arranged to protrude along the circumferential direction towards both sides of the tooth portion, the maximum distance between the two ends of the tooth shoe away from each other along the circumferential direction is W3, the maximum distance between the two ends of the core unit away from each other along the circumferential direction is W4, and 1.1<=W3 / W4<=1.3 is satisfied.

7. The electric machine of claim 1, wherein: the stator yoke comprises a plurality of yoke units arranged along the circumferential direction in sequence, at least one joint structure is arranged between two adjacent yoke units, one bending portion is connected between every two adjacent yoke units, and the plurality of stator teeth are correspondingly connected to the plurality of yoke units.

8. The electric machine of claim 1, wherein: the rotor assembly further comprises an inner core, the inner core is arranged in the space surrounded by the plurality of core units, and the inner core and the plurality of core units are disconnected from each other; and / or two adjacent core units are disconnected from each other.

9. A fan characterised by The wind wheel and the motor as claimed in any one of claims 1 to 8 are connected to the rotor assembly, and the wind wheel is installed on the rotating shaft of the rotor assembly.

10. An electrical appliance apparatus, characterized by, The fan as claimed in claim 9.

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