Stator core, stator assembly and motor

Abstract

This invention provides a stator core, a stator assembly, and a motor. The stator core includes a core body (1), a flow groove (2) on the outer circumference of the core body (1), stress holes (4) on both sides of the flow groove (2), and a protrusion (3) between adjacent flow grooves (2). In a cross-section perpendicular to the central axis of the core body (1), the flow groove (2) forms a first arc on the opening side near the outer circumference of the stator, and the first arc extends toward the side where the protrusion (3) is located. The stress holes (4) are located radially between the outer circumference of the stator and the bottom of the flow groove (2), and the portion of the stress holes (4) facing the first arc forms a second arc. According to the stator core of this invention, the influence of the opening on yoke saturation can be reduced, iron loss and harmonics can be reduced, and motor efficiency can be improved.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and more specifically, to a stator core, a stator assembly, and a motor. Background Technology

[0002] The motor stator is typically fixed to the casing of a hermetically sealed compressor via heat-shrink fitting or press-fitting. During these processes, compressive and tensile stresses are generated on the motor stator, causing hysteresis and expansion in the main magnetic circuit. This increases magnetic reluctance and can lead to increased iron losses, ultimately resulting in decreased motor efficiency. Furthermore, during compressor operation, the compressed refrigerant usually carries away some lubricating oil, compromising the compressor's oil return rate and affecting its reliability.

[0003] To address the aforementioned issues, existing technologies involve forming protrusions on the outer circumference of the stator and providing through holes at both ends of these protrusions. The deformation of these through holes at both ends of the protrusion absorbs the pressure exerted on the stator, thereby reducing the compressive stress generated on the inner circumference of the stator. However, due to the unreasonable structural design of the through holes, the original magnetic circuit structure is easily damaged, leading to increased harmonics and iron losses in the motor, and reduced motor efficiency. Summary of the Invention

[0004] The main objective of this invention is to provide a stator core, stator assembly, and motor that can reduce the impact of openings on yoke saturation, reduce iron losses and harmonics, and improve motor energy efficiency.

[0005] To achieve the above objectives, according to one aspect of the present invention, a stator core is provided, comprising a core body, a flow groove formed on the outer circumference of the stator core body, stress holes respectively provided on both sides of the flow groove, a protrusion formed between adjacent flow grooves, and in a cross section perpendicular to the central axis of the core body, the flow groove forms a first arc on the opening side near the outer circumference of the stator, the first arc extends toward the side where the protrusion is located, the stress holes are located radially on the outer circumference of the stator between the outer circumference of the stator and the bottom of the flow groove, and the portion of the stress holes facing the first arc forms a second arc.

[0006] Furthermore, within a cross-section perpendicular to the central axis of the core body, the stress hole is polygonal, and the stress hole includes a first side corresponding to the sidewall of the flow groove and a second side corresponding to the outer circle of the stator. The first side and the second side are connected by a second circular arc.

[0007] Furthermore, the maximum distance between the flow groove and the outer circle of the stator is L3, the length of the flow groove along the circumferential direction of the iron core body is G, and the radius of the outer circle of the stator is R3, where 43°≤arctan(0.5G / (R3-L3))≤51°, and 0.023*R3≤L3≤0.056*R3.

[0008] Furthermore, the second arc is concentric with the first arc, and the central angles of the arcs are the same.

[0009] Furthermore, the distance between the first side and the sidewall of the flow channel is L1, where 0.2mm≤L1≤0.3mm.

[0010] Furthermore, the distance between the second side and the outer circle of the stator is L2, where 0.2mm≤L2≤0.35mm.

[0011] Furthermore, the first side is parallel to the sidewall of the flow channel; and / or, along the direction away from the flow channel, the distance between the second side and the outer circle of the stator increases.

[0012] Furthermore, the stress hole is quadrilateral, and the stress hole also includes a third side and a fourth side. The third side is opposite to the first side, and the fourth side is opposite to the second side. Along the direction away from the flow channel, the distance between the second side and the fourth side decreases.

[0013] Furthermore, the second side and the third side, the third side and the fourth side, and the first side and the fourth side are all connected by a third arc, the radius of which is R2, 0.01mm≤R2≤0.03mm.

[0014] Furthermore, along the direction away from the flow channel, the distance between the fourth side and the outer circle of the stator decreases, and the maximum distance between the fourth side and the outer circle of the stator is less than the minimum distance between the bottom edge of the flow channel and the outer circle of the stator.

[0015] Furthermore, in a cross-section perpendicular to the central axis of the core body, the center of the core body is located on the extension line of the third side.

[0016] Furthermore, the maximum distance between the flow groove and the outer circle of the stator is L3, the length of the flow groove along the circumferential direction of the core body is G, the radius of the outer circle of the stator is R3, the included angle between the two third sides located on the same protrusion is O2, the number of stator teeth of the core body is Ns, 0.82*(360 / Ns-arctan(0.5G / (R3-L3)))≦O2≦0.88*(360 / Ns-arctan(0.5G / (R3-L3))).

[0017] Furthermore, the inner circumference of the iron core body is alternately provided with stator teeth and tooth grooves. In the cross section perpendicular to the central axis of the iron core body, the minimum distance between the bottom edge of the flow groove and the bottom edge of the tooth groove is L4, and the width of the stator teeth is L5, where L4≥0.89*L5.

[0018] Furthermore, the stress holes are filled with a filler material whose magnetic permeability is less than or equal to 1 / 10 of the magnetic permeability of the iron core body, and whose hardness is less than that of the iron core body.

[0019] Furthermore, within a cross-section perpendicular to the central axis of the core body, the two sidewalls of the same flow groove are parallel to each other and symmetrical about the centerline of the flow groove; and / or, stator teeth and tooth grooves are alternately arranged along the circumferential direction on the inner circumference of the core body, and the flow groove is located on the radial outer side of the stator teeth.

[0020] Furthermore, the inner radius of the iron core body is R4, the outer radius is R3, and 0.45≤R4 / R3≤0.53.

[0021] According to another aspect of the present invention, a stator assembly is provided, including a stator core, which is the stator core described above.

[0022] According to another aspect of the present invention, an electric motor is provided, characterized in that it includes the stator core described above or the stator assembly described above.

[0023] According to the technical solution of the present invention, the stator core includes a core body, a flow groove is formed on the outer circle of the stator core body, stress holes are respectively provided on both sides of the flow groove, and a protrusion is formed between adjacent flow grooves. In a cross section perpendicular to the central axis of the core body, the flow groove forms a first arc on the opening side near the outer circle of the stator, and the first arc extends towards the side where the protrusion is located. The stress hole is located in the radial direction of the outer circle of the stator between the outer circle of the stator and the bottom of the flow groove, and the part of the stress hole facing the first arc forms a second arc. The stator core features optimized placement and dimensions of stress holes, positioning them in stress concentration areas on both sides of the flow channel. These areas also serve as magnetic flux dispersion zones. By creating stress holes at these locations, stress on both sides of the flow channel is mitigated. Furthermore, the stress holes are located within the radial region of the protrusion, not exceeding its area and not encroaching on the stator yoke region. This reduces or even eliminates the impact on the yoke's magnetic circuit, increasing the stator core's power density. Combined with the flow channel structure, this design reduces stress on stator iron losses and the impact of openings on yoke saturation, while ensuring adequate compressor oil return and preventing harmonic generation. It also reduces iron losses and harmonics, mitigating harmonic and localized stress amplification issues caused by openings in the stator core, ultimately improving motor efficiency. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0025] Figure 1An assembly structure diagram of the stator core and outer shell according to an embodiment of the present invention is shown;

[0026] Figure 2 It shows Figure 1 A magnified structural diagram at point L;

[0027] Figure 3 A schematic diagram of the stress hole structure of the stator core according to an embodiment of the present invention is shown;

[0028] Figure 4 A structural dimension diagram of the stress hole in the stator core according to an embodiment of the present invention is shown;

[0029] Figure 5 A structural dimension diagram of the stress hole in the stator core according to an embodiment of the present invention is shown;

[0030] Figure 6 A structural dimension diagram of a stator core according to an embodiment of the present invention is shown;

[0031] Figure 7 A structural dimension diagram of a stator core according to an embodiment of the present invention is shown;

[0032] Figure 8 A simulation diagram of stress distribution in a heat-shrinkable stator without flow grooves is shown.

[0033] Figure 9 A simulation diagram of the stress distribution of an open-channel heat-shrinkable stator is shown.

[0034] Figure 10 A simulation diagram of the stress distribution of a heat-shrinkable stator with an open flow groove and a stress hole, according to an embodiment of the present invention, is shown.

[0035] Figure 11 A simulation diagram of the stator magnetic field distribution in an open-circuit slot is shown.

[0036] Figure 12 A stress distribution diagram of an open-slot heat-shrinkable stator is shown;

[0037] Figure 13 This diagram illustrates the stress distribution of a heat-shrinkable stator with an open stress hole and a flow groove, according to an embodiment of the present invention.

[0038] Figure 14 A simulation diagram of stress in the stator yoke of an open-channel heat-shrink sleeve is shown;

[0039] Figure 15 This invention illustrates a stress simulation diagram of the stator yoke portion of a heat-shrinkable sleeve with an open stress hole and a flow groove, according to an embodiment of the present invention.

[0040] Figure 16 A table showing motor efficiency test results under different operating conditions for stress-exposed and stress-free holes is presented.

[0041] Figure 17 The table shows the comprehensive energy efficiency of the stressed and unstressed holes under different operating conditions; and

[0042] Figure 18 The table shows the iron loss test results for motors at different frequencies under different operating conditions, including those with and without stress holes.

[0043] The above figures include the following reference numerals:

[0044] 1. Iron core body; 2. Flow groove; 3. Protrusion; 4. Stress hole; 5. First side; 6. Second side; 7. Third side; 8. Fourth side; 9. Stator tooth; 10. Tooth groove; 11. Outer shell. Detailed Implementation

[0045] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0046] See Figure 8 , Figure 9 , Figure 11 , Figure 12 and Figure 14 As shown, in related technologies, in order to improve the heat exchange capacity of the stator structure, a flow groove is generally opened on the stator structure. After the flow groove is opened, the stress distribution and the direction of the magnetic lines of force on the outside of the flow groove will be greatly affected, which will lead to serious stress concentration problems and adversely affect the magnetic circuit, causing the uniformity of magnetic lines of force distribution to cross, thereby affecting the working performance of the motor.

[0047] To address stress issues, related technologies have proposed solutions such as creating openings on both sides of the flow channel to adjust stress through the perforation structure. However, research indicates that existing solutions for optimizing the iron loss caused by stator stress often involve slotting the outside of the stator and creating openings in the stator protrusions. These methods fail to consider the alteration of stator stress distribution caused by the new structure and disrupt the original magnetic circuit structure, leading to a 2-3% increase in motor harmonics and a 15%-20% increase in harmonic losses. Iron losses in the stator stress concentration areas also increase by over 30%. These losses will reduce motor efficiency by more than 0.5%, significantly diminishing the overall optimization effect.

[0048] See also Figure 11 and Figure 12As shown in the figure, after the flow groove is created, the stress concentration points and magnetic flux dispersion points on both sides of the flow groove overlap in some locations. Based on this research, it is possible to reasonably create openings on the stator extension to ensure a uniform decrease in stress at each location of the yoke, while avoiding local stress increases and reducing the increase in iron loss caused by stress. Furthermore, the selection of this location takes into account the disruptive effect of the opening on the magnetic circuit, avoiding areas with dense magnetic flux distribution as much as possible to reduce the resulting harmonics and saturation effects. Combined with the flow groove structure, this can improve the motor's energy efficiency and vibration performance while ensuring the compressor's oil return volume and preventing harmonics.

[0049] See Figures 1 to 7 As shown, according to an embodiment of the present invention, the stator core includes a core body 1. The core body 1 has a flow groove 2 on the outer circle of the stator. Stress holes 4 are respectively provided on both sides of the flow groove 2. A protrusion 3 is formed between adjacent flow grooves 2. In a cross section perpendicular to the central axis of the core body 1, the flow groove 2 forms a first arc on the opening side near the outer circle of the stator. The first arc extends toward the side where the protrusion 3 is located. The stress holes 4 are located radially between the outer circle of the stator and the bottom of the flow groove 2. The portion of the stress holes 4 facing the first arc forms a second arc.

[0050] The stator core features optimized placement and dimensions of the stress holes 4, positioning them in stress concentration areas on both sides of the flow groove 2. These areas also serve as magnetic field dispersion zones. By opening stress holes 4 at these locations, stress on both sides of the flow groove 2 can be improved. Furthermore, the stress holes 4 are located within the radial region of the protrusion 3, not exceeding its area and not encroaching on the stator yoke region. Therefore, the impact on the yoke's magnetic circuit is reduced or even eliminated, increasing the stator core's power density. Combined with the flow groove 2 structure, this design reduces the impact of stress on stator iron losses and the saturation effect of the openings on the yoke, while ensuring compressor oil return and preventing harmonic generation. It also reduces iron losses and harmonics, improves the harmonic and localized stress amplification issues caused by openings in the stator core, and ultimately enhances motor efficiency.

[0051] In one embodiment, stator teeth 9 and tooth grooves 10 are alternately arranged along the inner circumference of the core body 1, and a flow groove 2 is disposed on the radially outer side of the stator teeth 9. In a preferred embodiment, the centerline of the flow groove 2 coincides with the centerline of the stator teeth 9.

[0052] Setting the flow groove 2 on the radial outer side of the stator tooth 9 has a smaller impact on the motor saturation compared to setting the flow groove 2 on the radial outer side of the tooth groove 10. It does not damage the magnetic circuit and can reduce the generation of harmonics.

[0053] In one embodiment, in a cross section perpendicular to the central axis of the core body 1, the stress hole 4 is polygonal. The stress hole 4 includes a first side 5 corresponding to the sidewall of the flow groove 2 and a second side 6 corresponding to the outer circle of the stator. The first side 5 and the second side 6 are connected by a second arc transition.

[0054] In this embodiment, by defining the two sides of the stress hole 4 near the flow groove 2, and matching the second arc between the two sides with the first arc on the opening side of the flow groove 2, the core width between the two arcs can be kept basically consistent. This effectively improves stress and allows magnetic lines of force to flow more evenly from the magnetic circuit between the first side 5 and the flow groove 2, as well as the radially outer magnetic circuit of the second side 6, thus optimizing the magnetic circuit formation and improving the magnetic performance of the motor. The radius of the second arc is R1.

[0055] In one embodiment, the maximum distance between the flow groove 2 and the outer circle of the stator is L3, the length of the flow groove 2 along the circumferential direction of the core body 1 is G, and the radius of the outer circle of the stator is R3, where 43°≤arctan(0.5G / (R3-L3))≤51°, and 0.023*R3≤L3≤0.056*R3.

[0056] In this embodiment, the structure of the flow channel 2 can be defined by the above method, so that the circumferential dimension and depth of the flow channel 2 are related to the radius R3 of the stator outer circle. The size design of the flow channel 2 is based on the radius R3 of the stator outer circle. This size ensures the flow of refrigerant without affecting the heat fit between the motor and the housing. If the angle exceeds this, the heat fit between the motor and the housing will not be secure, and if it is smaller, it will affect the flow of fluid.

[0057] In one embodiment, the second arc is concentric with the first arc, and the central angles of the arcs are the same. The first arc can be used to define the second arc, thereby adjusting the stress structure on both sides of the flow groove 2 through its structure. This ensures that the stress distribution on both sides of the flow groove 2 is located in the sparse region of the magnetic circuit, making it easier to set the stress holes 4. This minimizes the stress iron loss caused by the flow groove 2, reduces the impact of the stress holes 4 on the magnetic circuit, and improves the overall performance of the stress holes 4 in stress improvement and magnetic circuit distribution, thereby increasing the power density and operating performance of the motor. The concentricity of the second arc with the first arc ensures a uniform stress channel and better stress conduction.

[0058] In one embodiment, the distance between the first side 5 and the sidewall of the flow groove 2 is L1, where 0.2mm ≤ L1 ≤ 0.3mm. The size of L1 cannot be too small, as this would affect the mechanical strength at that point. However, if the size of L1 exceeds 0.3mm, it will significantly cause the stress on the second side 6 near the outer circle of the stator to be transmitted inward along the magnetic circuit between the first side 5 and the sidewall of the flow groove 2, which will increase the overall stress iron loss of the motor.

[0059] In one embodiment, within a cross-section perpendicular to the central axis of the core body 1, the two sidewalls of the same flow groove 2 are parallel to each other and symmetrical about the centerline of the flow groove 2.

[0060] In one embodiment, the first side 5 is parallel to the sidewall of the flow channel 2.

[0061] The two sides of the flow channel 2 are formed by straight lines E and F, which are parallel and symmetrical about the centerline of the flow channel 2. This structure is simple to manufacture. Compared with irregular side shapes, it is easier to process and more convenient to calculate the flow area, thus making it easier to control the gas-liquid flow rate at this location.

[0062] In one embodiment, the distance between the second side 6 and the outer circle of the stator is L2, where 0.2mm≤L2≤0.35mm.

[0063] Along the direction away from the flow groove 2, the distance between the second side 6 and the outer circle of the stator increases.

[0064] The radial distance from the intersection of the second side 6 and the third side 7 to the outer circle of the stator is L2. This design diverts the stress transmitted from the shell to the radially outer side of the second side 6 towards the side where the third side 7 is located. If the size of L2 is too small, the stress generated on the outer circle of the second side 6 will enter the stator yoke along the edge of the stress hole. This will aggravate the stress distribution density in the stator yoke, resulting in excessive local stress influence. The stress iron loss caused by this phenomenon is greater than the iron loss of uniformly distributed stress.

[0065] In one embodiment, the stress hole 4 is quadrilateral, and it further includes a third side 7 and a fourth side 8. The third side 7 is opposite to the first side 5, and the fourth side 8 is opposite to the second side 6. The distance between the second side 6 and the fourth side 8 decreases along the direction away from the flow groove 2. In this embodiment, setting the stress hole 4 as a quadrilateral makes it easier to design the magnetic circuit structure between the stress hole 4 and the flow groove 2. It also allows for optimization of the magnetic circuit orientation at other locations and can effectively improve the stress at those locations, thereby enhancing the mechanical performance of the motor.

[0066] In one embodiment, the second side 6 and the third side 7, the third side 7 and the fourth side 8, and the first side 5 and the fourth side 8 are all connected by a third arc transition, the radius of which is R2, 0.01mm≤R2≤0.03mm. The size of R2 can be selected according to the processing difficulty.

[0067] In one embodiment, the distance between the fourth side 8 and the outer circle of the stator decreases along the direction away from the flow groove 2, and the maximum distance between the fourth side 8 and the outer circle of the stator is less than the minimum distance between the bottom edge of the flow groove 2 and the outer circle of the stator. This structure minimizes the influence of the stress hole 4 on the magnetic circuit of the yoke, which would otherwise introduce corresponding harmonics, slightly increasing the motor's losses and vibration.

[0068] In one embodiment, the included angle between the second side 6 and the fourth side 8 of the stress hole 4 is O1.

[0069] In one embodiment, within a cross-section perpendicular to the central axis of the core body 1, the center of the core body 1 is located on the extension line of the third side 7. This limitation simplifies the structural design of the stress hole 4 and reduces its processing difficulty.

[0070] In one embodiment, the maximum distance between the flow groove 2 and the outer circle of the stator is L3, the length of the flow groove 2 along the circumferential direction of the core body 1 is G, the radius of the outer circle of the stator is R3, the included angle between the two third sides 7 located on the same protrusion 3 is O2, and the number of stator teeth of the core body 1 is Ns. 0.82*(360 / Ns-arctan(0.5G / (R3-L3)))≦O2≦0.88*(360 / Ns-arctan(0.5G / (R3-L3))). By limiting the structural relationship dimensions between the stress hole 4 and the protrusion 3, sufficient space can be left for the opening of the stress hole 4, allowing the stress hole 4 to be conveniently placed in the area with the least impact on the magnetic circuit, reducing the impact of the opening of the stress hole 4 on the magnetic circuit, and improving the power density of the motor.

[0071] In one embodiment, stator teeth 9 and tooth grooves 10 are alternately arranged along the inner circumference of the core body 1. In a cross-section perpendicular to the central axis of the core body 1, the minimum distance between the bottom edge of the flow groove 2 and the bottom edge of the tooth groove 10 is L4, and the width of the stator teeth 9 is L5, where L4 ≥ 0.89 * L5. The area defined by L4 is the easily saturated area of ​​the stator yoke. Ensuring the thickness here can reduce the saturation of the motor and reduce the harmonic content of the main magnetic field.

[0072] In one embodiment, the stress holes 4 are filled with a filler material whose magnetic permeability is less than or equal to 1 / 10 of the magnetic permeability of the core body 1, and whose hardness is less than that of the core body 1. By filling the stress holes 4 with the aforementioned filler material, the plastic deformation caused by the heat-shrinking of the stator core can be reduced or avoided without significantly affecting the magnetic circuit, thereby improving the structural strength of the motor.

[0073] In one embodiment, the inner radius of the iron core body 1 is R4, the outer radius is R3, and 0.45≤R4 / R3≤0.53. This range ensures the output torque of the motor while preventing the yoke thickness from becoming too thin, thus guaranteeing motor efficiency.

[0074] In one embodiment, the stress hole 4 is a through hole that runs axially through the entire core body 1.

[0075] See also Figure 10 , Figure 13 and Figure 15 As shown in the figure, after adopting the solution of the embodiment of the present invention, the opening of the stress hole 4 effectively improves the thermal stress of the stator core, while reducing the influence of the stress hole 4 on the magnetic circuit and ensuring the power density of the motor.

[0076] See also Figures 16 to 18 As shown, after adopting the solution of the present invention, compared with the structure that only opens the flow groove 2 and does not open the stress hole 4, the working efficiency of the motor is effectively improved, the iron loss is effectively reduced, and the overall energy efficiency of APF is significantly improved.

[0077] According to an embodiment of the present invention, the stator assembly includes a stator core, which is the stator core described above.

[0078] According to an embodiment of the present invention, the motor includes the stator core or the stator assembly described above. The motor also includes a housing 11, within which the stator core is located and thermally press-fitted with the housing 11. This motor combines the advantages of the aforementioned stator core, thus significantly improving thermal stress and reducing the impact of openings on the magnetic circuit, thereby increasing motor efficiency.

[0079] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0080] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A stator core, characterized in that, The core body (1) includes a flow groove (2) on the outer circle of the stator. Stress holes (4) are provided on both sides of the flow groove (2). A protrusion (3) is formed between adjacent flow grooves (2). In a cross section perpendicular to the central axis of the core body (1), the flow groove (2) forms a first arc on the opening side near the outer circle of the stator. The first arc extends toward the side where the protrusion (3) is located. The stress hole (4) is located radially between the outer circle of the stator and the bottom of the flow groove (2). The portion of the stress hole (4) facing the first arc forms a second arc. In a cross section perpendicular to the central axis of the core body (1), the stress hole (4) is polygonal. The stress hole (4) includes a first side (5) corresponding to the sidewall of the flow groove (2) and a second side (6) corresponding to the outer circle of the stator. The first side (5) and the second side (6) are connected by the second arc. The two arcs are concentric with the first arc, and the central angles of the arcs are the same; the stress hole (4) is quadrilateral, and the stress hole (4) also includes a third side (7) and a fourth side (8). The third side (7) is opposite to the first side (5), and the fourth side (8) is opposite to the second side (6). Along the direction away from the flow groove (2), the distance between the second side (6) and the fourth side (8) decreases; the maximum distance between the flow groove (2) and the outer circle of the stator is... The distance is L3, the length of the flow groove (2) along the circumferential direction of the iron core body (1) is G, the radius of the outer circle of the stator is R3, the included angle between the two third side edges (7) located on the same protrusion (3) is O2, the number of stator teeth of the iron core body (1) is Ns, 0.82*(360 / Ns-arctan(0.5G / (R3-L3)))≦O2≦0.88*(360 / Ns-arctan(0.5G / (R3-L3))).

2. The stator core according to claim 1, characterized in that, The maximum distance between the flow groove (2) and the outer circle of the stator is L3, the length of the flow groove (2) along the circumferential direction of the iron core body (1) is G, and the radius of the outer circle of the stator is R3, where 43°≤arctan(0.5G / (R3-L3))≤51°, 0.023*R3≤L3≤0.056*R3.

3. The stator core according to claim 1, characterized in that, The distance between the first side (5) and the sidewall of the flow channel (2) is L1, 0.2mm≤L1≤0.3mm.

4. The stator core according to claim 1, characterized in that, The distance between the second side (6) and the outer circle of the stator is L2, 0.2mm≤L2≤0.35mm.

5. The stator core according to claim 1, characterized in that, The first side (5) is parallel to the side wall of the flow groove (2); and / or, along the direction away from the flow groove (2), the distance between the second side (6) and the outer circle of the stator increases.

6. The stator core according to claim 1, characterized in that, The second side (6) and the third side (7), the third side (7) and the fourth side (8), and the first side (5) and the fourth side (8) are all connected by a third arc, the radius of which is R2, 0.01mm≤R2≤0.03mm.

7. The stator core according to claim 1, characterized in that, Along the direction away from the flow groove (2), the distance between the fourth side (8) and the outer circle of the stator decreases, and the maximum distance between the fourth side (8) and the outer circle of the stator is less than the minimum distance between the bottom edge of the flow groove (2) and the outer circle of the stator.

8. The stator core according to claim 1, characterized in that, In a cross section perpendicular to the central axis of the core body (1), the center of the core body (1) is located on the extension line of the third side (7).

9. The stator core according to any one of claims 1 to 8, characterized in that, The inner circumference of the iron core body (1) is alternately provided with stator teeth (9) and tooth grooves (10). In the cross section perpendicular to the central axis of the iron core body (1), the minimum distance between the bottom edge of the flow groove (2) and the bottom edge of the tooth groove (10) is L4, and the width of the stator teeth (9) is L5, where L4≥0.89*L5.

10. The stator core according to any one of claims 1 to 8, characterized in that, The stress hole (4) is filled with a filler material whose magnetic permeability is less than or equal to 1 / 10 of the magnetic permeability of the iron core body (1), and whose hardness is less than that of the iron core body (1).

11. The stator core according to any one of claims 1 to 8, characterized in that, In a cross section perpendicular to the central axis of the core body (1), the two side walls of the same flow groove (2) are parallel to each other and symmetrical about the center line of the flow groove (2); and / or, the inner circumference of the core body (1) is alternately provided with stator teeth (9) and tooth grooves (10) along the circumferential direction, and the flow groove (2) is located on the radial outer side of the stator teeth (9).

12. The stator core according to any one of claims 1 to 8, characterized in that, The inner radius of the iron core body (1) is R4, the outer radius is R3, and 0.45≤R4 / R3≤0.

53.

13. A stator assembly comprising a stator core, characterized in that, The stator core is the stator core according to any one of claims 1 to 12.

14. An electric motor, characterized in that, It includes the stator core according to any one of claims 1 to 12 or the stator assembly according to claim 13.

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