Electric motor, fan and electrical apparatus

Abstract

Disclosed in the present application are an electric motor, a fan and an electrical apparatus. The electric motor comprises a stator assembly (100) and a rotor assembly (200), wherein the stator assembly (100) comprises a stator core (110), the stator core (110) comprises a stator yoke portion (111) and a plurality of stator teeth (112), and the plurality of stator teeth (112) are connected to the inner peripheral wall of the stator yoke portion (111) and are arranged at intervals in the circumferential direction of the stator core (110); the rotor assembly (200) comprises a rotor core (210) and a plurality of permanent magnets (220); and the minimum outer diameter of the stator core (110) is D1, the minimum inner diameter of the stator core (110) is D2, the maximum outer diameter of the rotor core (210) is D3, the minimum inner diameter of the rotor core (210) is D4, and a coefficient K satisfies: 1.35≤K≤π×(D1<2>-D4<2>) / (D2+D3)<2>≤1.75.

Description

Motors, fans and electrical equipment

[0001] Cross-reference of related applications

[0002] This application claims priority to Chinese patent applications filed on January 24, 2025, with application number 202510121286.7 entitled "Electric Machines, Fans and Electrical Equipment" and application number 202520172289.9 entitled "Electric Machines, Fans and Electrical Equipment", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of motor technology, and in particular to a motor, a fan, and electrical equipment. Background Technology

[0004] As the performance of electrical equipment improves, the performance requirements for the motors within these devices also increase. For motors, output performance is closely related to the radial dimensions of the stator and rotor. To improve output performance, some technologies increase the radial dimensions of the stator and rotor; however, this leads to increased losses, decreased efficiency, and increased material usage, resulting in higher costs. Therefore, balancing motor output performance with production costs remains a problem that needs to be solved. Summary of the Invention

[0005] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a motor that can increase no-load back EMF, reduce losses, improve operating efficiency, and simultaneously reduce production costs.

[0006] This application also provides a fan and electrical equipment having the above-mentioned motor.

[0007] An electric motor according to a first aspect embodiment of this application includes a stator assembly comprising a stator core and a plurality of windings. The stator core is annular and has an inner hole. The stator core includes a stator yoke and a plurality of stator teeth. The plurality of stator teeth are connected to the inner peripheral wall of the stator yoke and are spaced apart circumferentially along the stator core. The plurality of windings are respectively wound around the plurality of stator teeth. A rotor assembly is rotatably disposed in the inner hole. The rotor assembly includes a rotor core and a plurality of permanent magnets. The rotor core has a plurality of mounting slots spaced apart circumferentially, and the plurality of permanent magnets are correspondingly mounted in the plurality of mounting slots. The minimum outer diameter of the stator core is D1, the minimum inner diameter of the stator core is D2, the maximum outer diameter of the rotor core is D3, the minimum inner diameter of the rotor core is D4, and a coefficient K satisfies:

[0008] The motor according to the first aspect embodiment of this application has at least the following beneficial effects: by adjusting and optimizing the minimum outer diameter D1 of the stator core, the minimum inner diameter D2 of the stator core, the maximum outer diameter D3 of the rotor core, and the minimum inner diameter D4 of the rotor core, it satisfies... In other words, by optimizing the ratio between the radial thickness of the motor and the armature diameter, the no-load back EMF of the motor is increased, thereby reducing losses and improving operating efficiency. This improves the output performance of the motor while saving material and reducing production costs.

[0009] According to some embodiments of this application, the minimum inner diameter D2 of the stator core satisfies: 58mm≤D2≤62mm.

[0010] According to some embodiments of this application, the number of stator teeth is N, each stator tooth includes a tooth portion and a tooth shoe. The tooth portion is connected to the inner peripheral wall of the stator yoke and extends toward the center of the stator core. The tooth shoe is connected to one end of the tooth portion away from the stator yoke and protrudes toward both sides of the tooth portion along the circumferential direction. The minimum tooth width of the tooth portion is W. The length of the tooth portion is L along the radial direction of the stator core. The minimum thickness of the stator yoke is H. A winding slot is defined between two adjacent stator teeth along the circumferential direction. The simplified cross-sectional area of ​​the winding slot is defined as S1, and the cross-sectional area of ​​the permanent magnet is defined as S2, satisfying: 2.6≤S2 / S1≤3.3;

[0011] in,

[0012] According to some embodiments of this application, the rotor core includes a plurality of core units arranged at intervals along the circumferential direction. The maximum distance between the two opposite sides of the core units along the circumferential direction is c. The mounting groove is defined between two adjacent core units. The simplified cross-sectional area of ​​the core unit is S3, and the cross-sectional area of ​​the permanent magnet is S2, satisfying: 0.75 ≤ S2 / S3 ≤ 1.5, where...

[0013] According to some embodiments of this application, the stator tooth includes a tooth portion and a tooth shoe. The tooth portion is connected to the inner peripheral wall of the stator yoke and extends toward the center of the stator core. The tooth shoe is connected to one end of the tooth portion away from the stator yoke and protrudes toward both sides of the tooth portion along the circumferential direction. The minimum tooth width of the tooth portion is W along the radial direction of the stator core. The minimum thickness of the stator yoke portion is H, satisfying: 1.5≤W / H≤2.2.

[0014] According to some embodiments of this application, 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.

[0015] According to some embodiments of this application, the rotor core includes a plurality of core units arranged at intervals along the circumferential direction, with adjacent core units disconnected from each other.

[0016] According to some embodiments of this application, the rotor assembly further includes an inner core disposed within a space surrounded by a plurality of core units, and the inner core is disconnected from the plurality of core units.

[0017] A wind turbine according to a second aspect of this application includes a wind turbine and a motor according to a first aspect of this application. The rotor assembly further includes a rotating shaft fixedly connected to the rotor core, and the wind turbine is mounted on the rotating shaft.

[0018] The fan according to the second aspect embodiment of this application has at least the following beneficial effects: Because the fan uses the aforementioned motor, by adjusting and optimizing the minimum outer diameter D1 of the stator core, the minimum inner diameter D2 of the stator core, the maximum outer diameter D3 of the rotor core, and the minimum inner diameter D4 of the rotor core, it satisfies… In other words, by optimizing the ratio between the radial thickness of the motor and the armature diameter, the no-load back EMF of the motor is increased, thereby reducing losses and improving operating efficiency. This improves the output performance of the motor while saving material and reducing production costs.

[0019] The electrical equipment according to the third aspect of this application includes the fan according to the second aspect of this application.

[0020] The electrical equipment according to the third aspect embodiment of this application has at least the following beneficial effects: Because the electrical equipment uses the aforementioned fan, by adjusting and optimizing the minimum outer diameter D1 of the stator core, the minimum inner diameter D2 of the stator core, the maximum outer diameter D3 of the rotor core, and the minimum inner diameter D4 of the rotor core, it satisfies… In other words, by optimizing the ratio between the radial thickness of the motor and the armature diameter, the no-load back EMF of the motor is increased, thereby reducing losses and improving operating efficiency. This improves the output performance of the motor while saving material and reducing production costs.

[0021] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

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

[0023] Figure 1 is a cross-sectional view of the motor in an embodiment of this application (with one of the permanent magnets hidden);

[0024] Figure 2 is a partial cross-sectional view of the stator core in an embodiment of this application;

[0025] Figure 3 is a cross-sectional view of the permanent magnet in an embodiment of this application;

[0026] Figure 4 is a cross-sectional view of the core unit in an embodiment of this application;

[0027] Figure 5 is a graph showing the per-unit value of the no-load back EMF as a function of K and the operating efficiency of the motor as a function of K in the embodiments of this application.

[0028] Figure 6 is a surface plot showing the variation of motor efficiency with the values ​​of S2 / S1 and S2 / S3 in an embodiment of this application; and

[0029] Figure 7 is a comparison of the output torque of the motor in the embodiment of this application and the output torque of the motor in the prior art solution as a function of input current.

[0030] Reference numerals: 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; Rotor assembly 200; Rotor core 210; Core unit 211; Outer magnetic bridge 2111; Inner magnetic bridge 2112; Mounting slot 212; Permanent magnet 220; Inner core 230; Air gap 240. Detailed Implementation

[0031] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0032] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0033] In the description of this application, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0034] In the description of this application, unless otherwise expressly defined, terms such as setting, installing, connecting, assembling, and cooperating should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0035] Referring to Figures 1 to 7, a first aspect of this application provides a motor used in electrical equipment, such as an air conditioner or a fresh air system. For example, the motor is used in the fan of an air conditioner as a power source to enable the fan to deliver air.

[0036] The following is a detailed description of the structure and components of the motor.

[0037] Referring to Figure 1, it can be understood that the motor includes a stator assembly 100 and a rotor assembly 200. Both the stator assembly 100 and the rotor assembly 200 are annular, with the stator assembly 100 arranged around the outer periphery of the rotor assembly 200. The inner peripheral wall of the stator assembly 100 and the outer peripheral wall of the rotor assembly 200 are spaced apart and form an air gap 240. In other words, the motor has an inner rotor structure.

[0038] Referring to Figure 1, it can be understood that the stator assembly 100 includes a stator core 110 and multiple windings. The stator core 110 is generally annular and typically consists of multiple stator laminations stacked along the central axis of the stator core 110. The stator core 110 includes a stator yoke 111 and multiple stator teeth 112. The stator yoke 111 is annular, and the multiple stator teeth 112 are all connected to the inner peripheral wall of the stator yoke 111 and extend radially toward the central axis of the stator core 110. The multiple stator teeth 112 are evenly spaced circumferentially around the stator core 110. Thus, the space located on the side of the multiple stator teeth 112 closest to the central axis of the stator core 110 forms the inner hole of the stator core 110. It is easy to understand 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 directions of the stator core 110. Along the radial direction of the stator core 110, the side closer to the central axis of the stator core 110 is the inner side, and the side farther away from the central axis of the stator core 110 is the outer side.

[0039] Referring to Figure 1, it can be understood that a winding slot 113 is defined between two adjacent stator teeth 112. 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. Multiple windings are respectively wound on multiple stator teeth 112, and each winding is accommodated in the winding slots 113 located on both sides of the corresponding stator tooth 112.

[0040] Referring to Figure 1, it can be understood that the stator assembly 100 is arranged around the outer periphery of the rotor assembly 200, that is, the rotor assembly 200 is located in the inner hole of the stator core 110, 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. The rotor core 210 is composed of a plurality of core units 211, the outer contour of which is approximately fan-shaped, and the smaller end of the fan-shaped core unit 211 is closer to the central axis of the stator core 110 than the larger end. The plurality of core units 211 are arranged at equal intervals along the circumference of the stator core 110, and a mounting slot 212 is defined between two adjacent core units 211. The number of mounting slots 212 is equal to the number of core units 211, and the number of mounting slots 212 and the number of core units 211 are equal to the number of permanent magnets 220. Multiple permanent magnets 220 are respectively installed in multiple mounting slots 212.

[0041] Referring to Figure 1, it can be understood that in this example, the motor is a twelve-slot, ten-pole motor, that is, there are twelve winding slots 113 and ten permanent magnets 220.

[0042] Of course, the number of slots and poles of a motor is not limited to twelve slots and ten poles; other combinations of slots and poles are also possible, which will not be elaborated here.

[0043] Referring to Figure 1, the minimum outer diameter of the stator core 110 is defined as D1, and the minimum inner diameter of the stator core 110 is defined as D2. In this embodiment, the outer contour of the stator core 110 is a regular polygon with the same number of sides as the number of winding slots 113, and both are even numbers, meaning the number of stator teeth 112 is also even. The inner wall surface of the stator teeth 112 is an arc-shaped surface. On the projection plane perpendicular to the central axis of the stator core 110, the minimum outer diameter D1 of the stator core 110 is the distance between two line segments symmetrically arranged about the central axis of the stator core 110 in the outer contour of the stator core 110. The minimum inner diameter D2 of the stator core 110 is the minimum distance of the line segments passing through the center of the stator core 110 (i.e., the projection of the central axis) and extending to the projection of the inner wall surfaces of the two stator teeth 112 symmetrically arranged about the central axis of the stator core 110.

[0044] Referring to Figure 1, the maximum outer diameter of the rotor core 210 is defined as D3, and the minimum inner diameter of the rotor core 210 is defined as D4. In this embodiment, the number of core units 211 is even. On the projection plane perpendicular to the central axis of the rotor core 210, the maximum outer diameter D3 of the rotor core 210 is the maximum distance of the line segment passing through the center of the rotor core 210 (i.e., the projection of the central axis) and extending to the projection of the outer wall surfaces of the two core units 211 arranged symmetrically about the central axis of the rotor core 210. The minimum inner diameter D4 of the rotor core 210 is the minimum distance of the line segment passing through the center of the rotor core 210 (i.e., the projection of the central axis) and extending to the projection of the inner wall surfaces of the two core units 211 arranged symmetrically about the central axis of the rotor core 210.

[0045] In other words, the minimum outer diameter D1 of the stator core 110 is the minimum value of the outer diameter at all points of the stator core 110, the minimum inner diameter D2 of the stator core 110 is the minimum value of the inner diameter at all points of the stator core 110, the maximum outer diameter D3 of the rotor core 210 is the maximum value of the outer diameter at all points of the rotor core 210, and the minimum inner diameter D4 of the rotor core 210 is the minimum value of the inner diameter at all points of the rotor core 210.

[0046] Referring to Figure 1, it can be understood that the coefficient K, the minimum outer diameter D1 of the stator core 110, the minimum inner diameter D2 of the stator core 110, the maximum outer diameter D3 of the rotor core 210, and the minimum inner diameter D4 of the rotor core 210 satisfy the following:

[0047] It is understandable that the radial thickness of the motor is defined as the radial distance between the outer contour of the stator core 110 and the inner contour of the rotor core 210. The armature diameter of the motor is defined as the diameter of a circle with the projection of the central axis of the stator core 110 onto the axial direction as its center and the distance between the midpoint of the air gap 240 in the radial direction and the center of the circle as its radius. The value of the armature diameter is...

[0048] Understandable, The area between the outer contour of the stator core 110 and the inner contour of the rotor core 210 is positively correlated with the size of the region, that is, it can reflect the thickness of the motor in the radial direction to a certain extent, and the correlation is positive.

[0049] Understandable, Its value is positively correlated with the area of ​​the circle containing the armature diameter, meaning it can reflect the size of the armature diameter to a certain extent, and the correlation is positive.

[0050] Therefore, in other words, K can reflect the ratio between the radial thickness of the motor and the armature diameter to a certain extent.

[0051] When K ≤ 1.35, in (D2 + D3) 2 Given a fixed value, i.e., the armature diameter remains constant, The value is too small, meaning the radial thickness of the motor is too small, the amount of windings and permanent magnet 220 is too small, meaning the number of turns of the windings and the magnetic flux of the permanent magnet 220 are both too small, resulting in a very small no-load back EMF of the motor; or in Given a fixed value, i.e., the radial thickness of the motor remains constant, (D2+D3) 2 The value is too large, resulting in an excessively large radial thickness of the stator core 110. If the thickness is too small, the magnetic flux of the stator core 110 is prone to saturation, and the number of turns in the winding decreases, while the radial thickness of the rotor core 210... If the magnet is too large, the amount of permanent magnet 220 increases but the utilization rate decreases, resulting in a decrease in the motor's output torque and a decrease in no-load back EMF; or... The value is too small, and at the same time (D2+D3) 2 The value is too large; please refer to the above explanation, which will not be repeated here.

[0052] When K≥1.75, in (D2+D3) 2 Given a fixed value, i.e., the armature diameter remains constant, The value is too large, meaning the radial thickness of the motor is too large, the amount of windings and permanent magnet 220 is too large, increasing the cost; or in Given a fixed value, i.e., the radial thickness of the motor remains constant, (D2+D3) 2 The value is too small; the radial thickness of rotor core 210 If the size is too small, the magnetic flux of the rotor core 210 is prone to saturation, the utilization of the permanent magnet 220 decreases, and the radial thickness of the stator core 110 is also affected. If the number of turns in the winding is too large, the utilization rate decreases, resulting in a decrease in the motor's output torque and a decrease in the no-load back EMF; or... The value is too large, and at the same time (D2+D3) 2 The value is too small; please refer to the above explanation, which will not be repeated here.

[0053] It is easy to understand that the no-load back EMF is positively correlated with the product of the number of turns of the winding and the magnetic flux of the permanent magnet 220.

[0054] Therefore, by ensuring that 1.35 ≤ K ≤ 1.75, for example, K values ​​of 1.35, 1.38, 1.4, 1.47, 1.6, 1.69, or 1.74, the minimum outer diameter D1 and minimum inner diameter D2 of the stator core 110, the maximum outer diameter D3 and minimum inner diameter D4 of the rotor core 210 are adjusted and optimized. This optimizes the ratio between the motor's radial thickness and the armature diameter. While maintaining the motor's output torque, the number of winding turns and the magnetic flux of the permanent magnet 220 are optimized, and the utilization rate of the windings and permanent magnet 220 is improved. This increases the motor's no-load back EMF by approximately 32%, while simultaneously reducing material usage and lowering costs by approximately 20%.

[0055] It is easy to understand that the output torque of a motor is positively correlated with the product of the no-load back EMF and the input current.

[0056] Given a fixed output torque, increasing the no-load back EMF reduces the input current, thereby lowering losses and improving the motor's operating efficiency, ultimately enhancing its output performance.

[0057] Referring to Figure 5, the figure shows the curves of the per-unit value of the no-load back EMF as a function of the value of K, and the curves of the motor's operating efficiency as a function of the value of K. The per-unit value of the no-load back EMF is a relative value based on the existing technology where the no-load back EMF is 1. From the two curves in the figure, it can be seen that as the value of K increases, both the per-unit value of the no-load back EMF and the motor's operating efficiency first increase and then decrease, reaching their maximum values ​​when K is around 1.55. When 1.35 ≤ K ≤ 1.75, both the per-unit value of the no-load back EMF and the motor's operating efficiency are relatively large, with the per-unit value of the no-load back EMF being approximately 1.15–1.3 and the motor's operating efficiency approximately 69%–73.5%. In other words, 1.35 ≤ K ≤ 1.75 can effectively improve the motor's no-load back EMF and operating efficiency.

[0058] In other embodiments, the outer contour of the stator core 110 may also be a polygonal shape (with a recess in the outer contour), a circle, or a closed loop formed by connecting multiple arc segments.

[0059] Understandably, the stator laminations that make up the stator core 110 are formed by stamping from sheet metal such as silicon steel plates. The shape of the stamped stator laminations can be ring-shaped; simply stacking multiple ring-shaped stator laminations in corresponding positions along the thickness direction yields the ring-shaped stator core 110. Alternatively, the shape of the stamped stator laminations can be chain-shaped; stacking multiple chain-shaped stator laminations in corresponding positions along the thickness direction yields a chain structure, which is then bent into a ring shape using a bending process and joined end to end to obtain the ring-shaped stator core 110.

[0060] It is understood that in this embodiment, the stator laminations obtained by punching are in a chain shape. Therefore, during material layout, the chain-shaped stator laminations are arranged in a straight line on the silicon steel sheet and other plates. This optimizes the layout, reduces waste, improves the material utilization rate of the plates, and thus reduces material costs.

[0061] Referring to Figures 1 and 2, specifically, in the stator core 110 composed of chain-like stator laminations, the stator yoke 111 includes multiple yoke units 1111, the number of which is equal to the number of stator teeth 112. The multiple yoke units 1111 are arranged sequentially along the circumference of the stator core 110 and form a ring. The multiple stator teeth 112 are respectively connected to the wall surface of the multiple yoke units 1111 on the side facing the central axis of the stator core 110.

[0062] Referring again to Figures 1 and 2, it can be understood that at least one pair of adjacent yoke units 1111 is provided with a splicing structure 1112, and each other pair of adjacent yoke units 1111 is connected by a bending portion 1113. Specifically, in this embodiment, the stator core 110 is composed of a chain-like structure. After the chain-like structure is assembled into a ring, the first and last two yoke units 1111 are joined together by the splicing structure 1112. The splicing structure 1112 can be a dovetail groove structure, a concave-convex fit structure, etc. Each other pair of adjacent yoke units 1111 is connected by a bending portion 1113. The bending portion 1113 allows the adjacent two yoke units 1111 to be bent relative to each other in a direction perpendicular to the central axis of the stator core 110, so that the chain-like structure can be bent into a ring-shaped stator core 110, which is convenient for production.

[0063] Of course, the stator core 110 is composed of multiple chain-like structures spliced ​​together in sequence to form a ring. Adjacent chain-like structures are connected by splicing structure 1112. In each chain-like structure, a bending part 1113 is connected between every two adjacent yoke units 1111, which will not be described in detail here.

[0064] Referring to Figure 1, it can be understood that the minimum inner diameter D2 of the stator core 110 satisfies: 58mm ≤ D2 ≤ 62mm. For example, D2 can be 58mm, 59mm, 59.5mm, 61.3mm, or 62mm, etc. Given a fixed radial width of the air gap 240, a larger minimum inner diameter D2 of the stator core 110 results in a larger armature diameter for the motor, thereby increasing the radial thickness of the rotor core 210. By reducing the saturation level of the rotor core 210 and increasing the amount of permanent magnets 220, the output torque and no-load back EMF of the motor are increased, thereby improving the output performance of the motor.

[0065] It is easy to understand that, due to the increased amount of permanent magnet 220, the magnetic field stability of permanent magnet 220 is high and the anti-demagnetization ability is enhanced, which makes the demagnetizing current required for permanent magnet 220 to demagnetize larger, achieving a demagnetizing current increase of about 30%, which is beneficial to improving the demagnetizing performance of the motor.

[0066] Referring to FIG2, it can be understood that the stator tooth 112 includes a tooth portion 1121 and a tooth shoe 1122. The tooth portion 1121 is connected to the inner peripheral wall of the stator yoke portion 111 and extends radially toward the center of the stator core 110. The tooth shoe 1122 is connected to one end of the tooth portion 1121 away from the stator yoke portion 111, and the tooth shoe 1122 protrudes along the circumference of the stator core 110 toward both sides of the tooth portion 1121.

[0067] Referring to Figure 2, it can be understood that the minimum tooth width of the tooth 1121 is defined as W, and the radial length of the tooth 1121 along the stator core 110 is L. W is the minimum distance between two opposing walls of the tooth 1121 along the circumference of the stator core 110. Generally, the two opposing walls of the tooth 1121 along the circumference of the stator core 110 are parallel. L is the radial distance between the two ends of the tooth 1121 along the radial direction of the stator core 110.

[0068] Referring to Figure 2, it can be understood that the minimum thickness of the stator yoke 111 along the radial direction of the stator core 110 is defined as H. H is the minimum thickness of the yoke unit 1111, which is also the minimum distance between two opposing walls of the yoke unit 1111 along the radial direction of the stator core 110. Generally speaking, the two opposing walls of the yoke unit 1111 along the radial direction of the stator core 110 are parallel.

[0069] Referring to Figure 2, it can be understood that the number of stator teeth 112 is defined as N. On the projection plane perpendicular to the central axis of the rotor core 210, the angle between the midpoint of the projection of one of the two walls that are circumferentially opposite to the stator core 110 along the tooth portion 1121 and the projection of the central axis of the stator core 110, and the center line of symmetry of the tooth portion 1121 passing through the central axis of the stator core 110, is defined as θ.

[0070] Referring to Figure 2, it can be understood that the simplified cross-sectional area of ​​the winding slot 113 is defined as S1. On the projection plane perpendicular to the central axis of the rotor core 210, the simplified cross-sectional area of ​​the winding slot 113 is the area enclosed by the projections of the two opposing walls of the winding slot 113 along the circumference of the stator core 110, the line connecting the ends of the two projections near the central axis of the stator core 110, and the line connecting the ends of the two projections away from the central axis of the stator core 110. This area is typically an isosceles trapezoid. The simplified cross-sectional area S1 of the winding slot 113 reflects, to some extent, the amount of winding used, i.e., the number of turns of the winding.

[0071] in,

[0072] Referring to Figure 3, it can be understood that the cross-sectional area of ​​the permanent magnet 220 is defined as S2. The maximum radial length of the permanent magnet 220 along the rotor core 210 is a, which is the maximum distance between two opposing walls of the permanent magnet 220 along the radial direction of the rotor core 210. The maximum circumferential thickness of the permanent magnet 220 along the rotor core 210 is b, which is the maximum distance between two opposing walls of the permanent magnet 220 along the circumferential direction of the rotor core 210. Generally, on the projection plane perpendicular to the central axis of the rotor core 210, the projection of the permanent magnet 220 is rectangular, with a length of a and a width of b, then S2 = a * b. The cross-sectional area of ​​the permanent magnet 220, S2, reflects to some extent the amount of permanent magnet 220 used, that is, the magnetic flux of the permanent magnet 220.

[0073] Referring to Figures 2 and 3, it can be understood that the simplified cross-sectional area S1 of the winding groove 113 and the cross-sectional area S2 of the permanent magnet 220 satisfy: 2.6≤S2 / S1≤3.3.

[0074] When S2 / S1 < 2.6, the cross-sectional area S2 of the permanent magnet 220 is too small, resulting in low magnetic flux. The simplified cross-sectional area S1 of the winding slot 113 is too large, leading to a large number of turns in the winding. This makes the magnetic flux of the stator core 110 prone to saturation, reducing the utilization rate of the winding and causing a decrease in the motor's output torque. Furthermore, the product of the number of turns in the winding and the magnetic flux of the permanent magnet 220 is relatively small, resulting in a decrease in the no-load back EMF and efficiency. When S2 / S1 > 3.3, the cross-sectional area S2 of the permanent magnet 220 is too large, resulting in high magnetic flux. This makes the magnetic flux of the rotor core 210 prone to saturation, reducing the utilization rate of the permanent magnet 220. The simplified cross-sectional area S1 of the winding slot 113 is too small, resulting in a small number of turns in the winding. This also leads to a decrease in the motor's output torque. The product of the number of turns in the winding and the magnetic flux of the permanent magnet 220 is relatively small, resulting in a decrease in the no-load back EMF and efficiency.

[0075] Therefore, by optimizing the cross-sectional area S1 of the winding slot 113 and the cross-sectional area S2 of the permanent magnet 220, the ratio of the cross-sectional area S2 of the permanent magnet 220 to S1 of the winding slot 113 is kept within a suitable range. This optimizes the number of turns of the winding and the amount of permanent magnet 220 used, thereby improving the utilization rate of the winding and permanent magnet, and increasing the output torque, no-load back EMF and operating efficiency of the motor.

[0076] Referring to Figure 4, it can be understood that 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 circumference 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 circumference of the rotor core 210. The outer magnetic bridges 2111 and the inner magnetic bridges 2112 respectively abut against the two ends of the permanent magnet 220 in the radial direction to achieve positioning of the permanent magnet 220.

[0077] Referring to Figure 1, it can be understood that the disconnection between two adjacent core units 211 helps to reduce magnetic leakage and improve the utilization rate of the permanent magnet 220.

[0078] Referring to Figure 1, it can be understood that in this embodiment, the rotor assembly 200 also includes an inner core 230, which is disposed within the space surrounded by multiple core units 211. Typically, the inner core 230 has a shaft hole in its center for the shaft to pass through, and the shaft is fixedly connected to the inner core 230. The inner core 230 is disconnected from the multiple core units 211, which helps to further reduce magnetic leakage and improve the utilization rate of the permanent magnets 220. It is readily understood that the multiple core units 211, the multiple permanent magnets 220, the inner core 230, and the shaft are filled with injection-molded material to achieve interconnection and fixation, thereby improving the structural stability of the rotor assembly 200.

[0079] Referring to Figure 4, it can be understood that the maximum distance between the two opposite ends of the two external magnetic bridges 2111 along the circumference of the rotor core 210 is defined as c, and the simplified cross-sectional area of ​​the core unit 211 is S3. Since the core unit 211 is roughly fan-shaped, the simplified cross-sectional area of ​​the core unit 211 can be understood as having c as the base. The area of ​​the triangle with the height is the area of ​​the dashed triangle in Figure 4. In other words, The simplified cross-sectional area S3 of the core unit 211 reflects, to some extent, the amount of rotor core 210 used.

[0080] Referring to Figures 3 and 4, it can be understood that the cross-sectional area S2 of the permanent magnet 220 and the simplified cross-sectional area S3 of the core unit 211 satisfy: 0.75≤S2 / S3≤1.5.

[0081] When S2 / S3 < 0.75, the cross-sectional area S2 of the permanent magnet 220 is too small, resulting in a small magnetic flux. Under the premise that the number of turns in the winding remains unchanged, the product of the number of turns in the winding and the magnetic flux of the permanent magnet 220 is small, leading to a decrease in the no-load back EMF and a decrease in the output torque of the motor. The simplified cross-sectional area S3 of the core unit 211 is too large, increasing costs and losses, and reducing the operating efficiency of the motor. When S2 / S3 > 1.5, the cross-sectional area S2 of the permanent magnet 220 is too large, increasing costs. Although the magnetic flux of the permanent magnet 220 is large, the simplified cross-sectional area S3 of the core unit 211 is too small, making the magnetic flux of the core unit 211 prone to saturation, which leads to a decrease in the utilization rate of the permanent magnet 220 and also results in a decrease in the operating efficiency of the motor.

[0082] Therefore, by ensuring that 0.75 ≤ S2 / S3 ≤ 1.5, for example, the value of S2 / S3 is 0.75, 0.79, 0.86, 1.1, 1.21, 1.34, 1.43, or 1.5, the cross-sectional area S2 of the permanent magnet 220 and the simplified cross-sectional area S3 of the iron core unit 211 are optimized and adjusted so that the ratio of the cross-sectional area S2 of the permanent magnet 220 to the simplified cross-sectional area S3 of the iron core unit 211 is within a suitable range. That is, the amount of permanent magnet 220 and the amount of iron core unit 211 are optimized, thereby improving the no-load back EMF and output torque of the motor, reducing losses, and improving operating efficiency.

[0083] Referring to Figure 6, the graph shows the variation of motor efficiency with the values ​​of S2 / S1 and S2 / S3. It can be seen from the graph that, when the value of S2 / S3 is constant, the motor efficiency first increases and then decreases as the value of S2 / S1 increases; similarly, when the value of S2 / S1 is constant, the motor efficiency first increases and then decreases as the value of S2 / S3 increases. Furthermore, the motor efficiency is at its maximum, approximately 73.5%, when the values ​​of S2 / S1 are approximately 3 and S2 / S3 are approximately 1.2. When 2.6 ≤ S2 / S1 ≤ 3.3 and 0.75 ≤ S2 / S3 ≤ 1.5, the motor efficiency remains above approximately 68%. Therefore, it is evident that 2.6 ≤ S2 / S1 ≤ 3.3 and 0.75 ≤ S2 / S3 ≤ 1.5 can effectively improve motor efficiency.

[0084] Referring to Figure 2, it can be understood that the minimum tooth width W of the tooth portion 1121 and the minimum thickness H of the stator yoke 111 satisfy the following condition: 1.5 ≤ W / H ≤ 2.2. When W / H < 1.5, the minimum width W of the tooth portion 1121 is too small, and the magnetic flux of the tooth portion 1121 is prone to saturation, which will lead to a decrease in the output torque of the motor. The minimum thickness H of the stator yoke 111 is too large, which increases the material and cost. When W / H > 2.2, the minimum thickness H of the stator yoke 111 is too small, and the magnetic flux of the stator yoke 111 is prone to saturation, which will lead to a decrease in the output torque of the motor. The minimum tooth width of the tooth portion 1121 is too large, which increases the material and cost.

[0085] Therefore, by setting 1.5 ≤ W / H ≤ 2.2, for example, the value of W / H is 1.5, 1.63, 1.78, 1.82, 1.95, 2.1 or 2.2, etc., to adjust the minimum tooth width of the tooth portion 1121 and the minimum thickness of the stator yoke portion 111, so that the ratio of the minimum tooth width W of the tooth portion 1121 to the minimum thickness H of the stator yoke portion 111 is within a suitable range, thereby reducing the magnetic flux saturation of the stator core 110, increasing the output torque of the motor, and reducing material costs.

[0086] Referring to Figure 7, it can be understood that the figure shows a comparison of the output torque curves of the motor in this embodiment and the motor in the prior art solution as a function of input current. From the two curves in the figure, it can be seen that under light load conditions, i.e., when the input current is small (specifically, within the range of 0A to 0.6A), the two curves basically overlap. Under heavy load conditions, i.e., when the input current is small (specifically, within the range of 0.6A to 1.6A), the curve of this embodiment is above the curve of the prior art solution. In other words, under light load conditions, the output torque of the motor in this embodiment is basically equal to that of the motor in the prior art solution, while under heavy load conditions, the output torque of the motor in this embodiment is greater than that of the motor in the prior art solution. The motor in this embodiment has good heavy load capacity and improves overload capacity to a certain extent.

[0087] The fan of the second aspect of this application includes a wind turbine and a motor of the first aspect of this application, wherein the wind turbine is mounted on a rotating shaft.

[0088] Since the fan adopts all the technical solutions of the motor in the above embodiments, it has at least all the beneficial effects brought about by the technical solutions in the above embodiments.

[0089] The electrical equipment in the third aspect of this application includes the fan in the second aspect of this application. The electrical equipment may be an air conditioner, a fresh air unit, etc.

[0090] Since the electrical equipment adopts all the technical solutions of the fan in the above embodiments, it has at least all the beneficial effects brought about by the technical solutions in the above embodiments.

[0091] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. An electric motor, including: A stator assembly includes a stator core and multiple windings. The stator core is annular and has an inner hole. The stator core includes a stator yoke and multiple stator teeth. The multiple stator teeth are connected to the inner peripheral wall of the stator yoke and arranged at intervals along the circumference of the stator core. The multiple windings are respectively wound around the multiple stator teeth. A rotor assembly is rotatably disposed in the inner hole. The rotor assembly includes a rotor core and a plurality of permanent magnets. The rotor core is provided with a plurality of mounting slots arranged at intervals along the circumference. The plurality of permanent magnets are correspondingly mounted in the plurality of mounting slots. Wherein, the minimum outer diameter of the stator core is D1, the minimum inner diameter of the stator core is D2, the maximum outer diameter of the rotor core is D3, the minimum inner diameter of the rotor core is D4, the coefficient K, satisfies:

2. The motor according to claim 1, wherein the minimum inner diameter D2 of the stator core satisfies: 58mm≤D2≤62mm.

3. The electric machine of claim 1 or 2, wherein, The number of stator teeth is N. Each stator tooth includes a tooth portion and a tooth shoe. The tooth portion is connected to the inner peripheral wall of the stator yoke and extends toward the center of the stator core. The tooth shoe is connected to the end of the tooth portion away from the stator yoke and protrudes toward both sides of the tooth portion along the circumferential direction. The minimum tooth width of the tooth portion is W. The length of the tooth portion is L along the radial direction of the stator core. The minimum thickness of the stator yoke is H. A winding slot is defined between two adjacent stator teeth along the circumferential direction. The simplified cross-sectional area of ​​the winding slot is defined as S1. The cross-sectional area of ​​the permanent magnet is defined as S2, satisfying: 2.6≤S2 / S1≤3.3; wherein 4. The electric machine of any one of claims 1 to 3, wherein, The rotor core comprises multiple core units arranged at intervals along the circumference. The maximum distance between opposite sides of the core units along the circumference is c. The mounting slot is defined between two adjacent core units. The simplified cross-sectional area of ​​the core unit is S3, and the cross-sectional area of ​​the permanent magnet is S2, satisfying: 0.75 ≤ S2 / S3 ≤ 1.

5.

5. The electric machine of any one of claims 1 to 4, wherein, The stator tooth includes a tooth portion and a tooth shoe. The tooth portion is connected to the inner peripheral wall of the stator yoke and extends toward the center of the stator core. The tooth shoe is connected to one end of the tooth portion away from the stator yoke and protrudes toward both sides of the tooth portion along the circumferential direction. The minimum tooth width of the tooth portion is W along the radial direction of the stator core. The minimum thickness of the stator yoke portion is H, satisfying: 1.5≤W / H≤2.

2.

6. The electric machine of any one of claims 1 to 5, wherein, The stator yoke includes a plurality of yoke units arranged sequentially along the circumference. At least one of the adjacent two yoke units is provided with a splicing structure, and each of the other adjacent two yoke units is connected by a bend. The plurality of stator teeth are respectively connected to the plurality of yoke units.

7. The electric machine of any one of claims 1 to 6, wherein, The rotor core includes a plurality of core units arranged at intervals along the circumference, with adjacent core units disconnected from each other.

8. The electric machine of claim 7, wherein, The rotor assembly also includes an inner core, which is disposed within the space surrounded by the plurality of core units, and the inner core is disconnected from the plurality of core units.

9. A fan comprising a fan wheel and the electric machine of any one of claims 1 to 8, wherein, The rotor assembly also includes a rotating shaft fixedly connected to the rotor core, and the impeller is mounted on the rotating shaft.

10. Electrical equipment, including the fan as described in claim 9.

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