Stator core, motor, and generator

Abstract

The invention relates to a stator core, a motor and a generator. The stator core is provided with: a core wire section having a spiral shape with a constant distance from the central axis, the core wire section being formed of a wire made of electromagnetic soft iron or silicon steel; and an insulating film covering the outer peripheral surface of the core wire portion. A first proportion, which is the proportion of crystals in which the angle formed between the radial direction of the helix and the direction of the iron [100] is not more than 15 degrees, is 10% or more.

Description

Technical Field

[0001] This disclosure relates to stator cores, electric motors, and generators. This application claims priority based on Japanese Application No. 2023-199294, filed on November 24, 2023, and invokes all the contents described in that Japanese application. Background Technology

[0002] A stator core with a helical shape and a constant distance from the central axis is known (see, for example, Patent Document 1). The stator core described in Patent Document 1 is manufactured by punching an electromagnetic steel sheet.

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2024-13954 Summary of the Invention

[0004] The stator core according to this disclosure comprises: a core wire portion having a helical shape at a constant distance from the central axis, said stator core being made of wire made of electromagnetic soft iron or silicon steel; and an insulating film covering the outer peripheral surface of the core wire portion. A first proportion of the crystals whose radial angle with the iron

[100] direction is within 15 degrees is greater than or equal to 10%. Attached Figure Description

[0005] Figure 1 This is a schematic perspective view showing the structure of the stator core in this embodiment.

[0006] Figure 2 Is and includes Figure 1 The diagram corresponding to the cross section along the central axis A (along...) Figure 1 (Sectional view of line segment II-II).

[0007] Figure 3 It is a schematic cross-sectional view showing the structure of the core wire portion and the insulating film that make up the stator core.

[0008] Figure 4 This is a flowchart outlining the manufacturing process of the stator core.

[0009] Figure 5A This is an enlarged cross-sectional view of a portion of the stator core in the first variant.

[0010] Figure 5B This is an enlarged cross-sectional view of a portion of the stator core in a further modification of the first modification.

[0011] Figure 5C This is an enlarged cross-sectional view of a portion of the stator core in the second variation.

[0012] Figure 5DThis is an enlarged cross-sectional view of a portion of the stator core in the third variation.

[0013] Figure 5E This is an enlarged cross-sectional view of a portion of the stator core in a further modification of the third modification.

[0014] Figure 5F This is an enlarged cross-sectional view of a portion of the stator core in the fourth variation.

[0015] Figure 5G This is an enlarged cross-sectional view of a portion of the stator core in the fifth variation.

[0016] Figure 6 This is a perspective view of the electric motor and generator in this embodiment.

[0017] Figure 7 It is along Figure 6 A cross-sectional view along the XX line.

[0018] Figure 8 This is a top view of the stator core of sample D, which is manufactured by punching an electromagnetic steel sheet. Detailed Implementation

[0019] [The problem this disclosure aims to solve] In the stator core disclosed in the aforementioned Patent Document 1, the saturation magnetic flux density is low.

[0020] One of the purposes of this disclosure is to provide a stator core with high saturation flux density.

[0021] [Effects of this disclosure] The stator core disclosed herein can provide a stator core with a high saturation magnetic flux density.

[0022] [Description of embodiments of this disclosure] First, the implementation plan disclosed herein will be listed for illustration.

[0023] (1) The stator core of this disclosure comprises: a core wire portion having a helical shape at a constant distance from the central axis, said stator core being made of electromagnetic soft iron or silicon steel wire; and an insulating film covering the outer peripheral surface of the core wire portion. In the core wire portion, the proportion of crystals whose radial angle with the direction of the helix is ​​within 15 degrees is greater than or equal to 10%.

[0024] In this stator core, the first proportion is as high as 10% or more. A stator core with high saturation magnetic flux density can be obtained by unifying the orientation of the crystals contained in the core wire section to this extent.

[0025] (2) In (1) above, the standard deviation of the second proportion in the first part, the second part and the third part of the outer peripheral surface is less than or equal to 0.2%, wherein the second part is the part that is 120 degrees away from the first part in the circumferential direction around the central axis, and the third part is the part that is 120 degrees away from the first part and the second part in the circumferential direction around the central axis.

[0026] In electromagnetic steel sheets, the crystals are aligned so that specific crystal faces align with the rolling direction. Therefore, in a stator core manufactured by punching and stacking annular sheets of electromagnetic steel, even assuming the rolling direction is aligned with the circumferential direction in the first part, the rolling direction is not aligned with the circumferential direction in the second and third parts, which are 120 degrees apart from the first part in the circumferential direction around the central axis. Therefore, even if the proportion of crystals with a small angle between the radial direction of the helix and the iron

[100] direction is high in the first part, the proportion of crystals with a small angle between the radial direction of the helix and the iron

[100] direction will necessarily be lower in the second and third parts.

[0027] For example, if the shaped wire is wound, the forming direction in the core wire portion of the stator core is consistent with the circumferential direction in the first, second, and third parts. Therefore, the proportion of crystals with a small angle between the radial direction of the helix and the direction of iron

[100] becomes higher.

[0028] (3) The stator core of this disclosure comprises: a core wire portion having a helical shape with a constant distance from the central axis, said stator core being made of electromagnetic soft iron or silicon steel wire; and an insulating film covering the outer peripheral surface of the core wire portion. It comprises: an insulating film covering the outer peripheral surface of the core wire portion. The second proportion of crystals, representing the ratio of the radial direction of the helix to the iron

[100] direction at an angle of 20 degrees or less, is greater than or equal to 20%.

[0029] In this stator core, the second proportion is as high as 20% or more. A stator core with high saturation magnetic flux density can be obtained by unifying the orientation of the crystals contained in the core wire section to this extent.

[0030] (4) In (3) above, the standard deviation of the second proportion in the first, second, and third portions of the outer peripheral surface may be less than or equal to 0.2, wherein the second portion is the portion 120 degrees away from the first portion in the circumferential direction around the central axis, and the third portion is the portion 120 degrees away from the first and second portions in the circumferential direction around the central axis. For example, if the formed wire is wound, the rolling direction in the core wire portion of the stator core is consistent with the circumferential direction in the first, second, and third portions. Therefore, the proportion of crystals with a small angle between the radial direction of the helix and the direction of iron

[100] becomes higher.

[0031] (5) In any of (1) to (4) above, the insulating films covering adjacent core wire portions in a direction parallel to the central axis in the cross section containing the central axis may also be in contact with each other. With this configuration, further reduction of iron loss can be achieved.

[0032] (6) In any of (1) to (4) above, the stator core may also include a resin portion covered with an insulating film. In a cross-section including the central axis, the resin portion includes at least one selected from the group consisting of a first portion, a second portion, and a third portion. The first portion covers an insulating film located on the side opposite to the central axis when viewed from the core wire portion. The second portion covers an insulating film located between the core wire portion and the central axis. The third portion is located between the insulating films of the core wire portions that are adjacent to each other in a direction parallel to the central axis. With this configuration, the insulation of the core wire portion can be improved.

[0033] (7) In (6) above, the resin part may also be a cured body that bonds the insulating film covering the core wire parts that are adjacent to each other in a direction parallel to the central axis. With this configuration, the shape stability of the iron wire with insulating film, including the first part, the second part and the insulating film, can be improved.

[0034] (8) In any of (1) to (7) above, the cross-section of the core wire portion perpendicular to the longitudinal direction may also be rectangular. With this configuration, the space between adjacent core wire portions in the direction parallel to the central axis is reduced. As a result, a further increase in maximum permeability and saturation flux density can be achieved.

[0035] (9) In any of (1) to (8) above, the height of the cross section of the core wire portion perpendicular to the longitudinal direction and parallel to the central axis is less than or equal to 0.6 mm. With this configuration, eddy current loss is reduced, and as a result, iron loss is reduced.

[0036] (10) In any of (1) to (9) above, the insulating film may also be made of an inorganic material. Inorganic materials are preferred as the material of the insulating film covering the core wire portion.

[0037] (11) In (10) above, the inorganic material may also be phosphate. From the viewpoints of insulation properties, cost, and ease of forming the insulating film, phosphate is particularly preferred as a material for the insulating film covering the core wire.

[0038] (12) In any of (1) to (11) above, the thickness of the insulating film may be greater than or equal to 0.1 μm and less than or equal to 30 μm. If the thickness of the insulating film is less than 0.1 μm, the insulation between adjacent core wire portions in the direction parallel to the central axis may be insufficient. On the other hand, if the thickness of the insulating film exceeds 30 μm, the maximum permeability may be insufficient. Therefore, it is preferable that the thickness of the insulating film is set within the above range. From the viewpoint of ensuring higher maximum permeability and saturation magnetic flux density, it is more preferable that the thickness of the insulating film is less than or equal to 5 μm.

[0039] (13) In any of (1) to (12) above, the aspect ratio of the length of the stator core in the direction parallel to the central axis to the outer diameter of the stator core is greater than or equal to 3. With this configuration, the torque of the motor equipped with the stator core can be improved, or the power generation performance of the generator equipped with the stator core can be improved, and the motor or generator can be miniaturized.

[0040] (14) The electric motor of this disclosure has any one of the stator cores (1) to (13) above. The electric motor has a stator core with a high maximum permeability, and therefore the motor has high torque.

[0041] (15) The generator of this disclosure has any one of the stator cores (1) to (13) above. The generator has a stator core with a high maximum permeability, and therefore the generator has high power generation efficiency.

[0042] [Details of the embodiments disclosed herein] Next, embodiments of the stator core of this disclosure will be described with reference to the accompanying drawings. It should be noted that in the following drawings, the same or equivalent parts will be labeled with the same reference numerals, and their description will not be repeated.

[0043] Figure 1 This is a schematic perspective view showing the structure of the stator core in this embodiment. Figure 2 Is and includes Figure 1 The diagram corresponding to the cross section along the central axis A (along...) Figure 1 (Sectional view of line segment II-II). Figure 3 It is a schematic cross-sectional view showing the structure of the core wire portion and the insulating film that make up the stator core.

[0044] Reference Figure 1 In this embodiment, the stator core 1 has an iron wire 10 with an insulating film wound into a spiral shape at a constant distance from the central axis A. (Refer to...) Figure 1 and Figure 2 The stator core 1 has a core wire portion 11 and an insulating film 12. The core wire portion 11 and the insulating film 12 constitute an iron wire 10 with an insulating coating.

[0045] [Core wire section 11] The core wire portion 11 has a spiral shape with a constant distance r from the central axis A. The core wire portion 11 is made of a metal wire made of electromagnetic soft iron or silicon steel. In this disclosure, electromagnetic soft iron refers to the electromagnetic soft iron specified in JIS standard C2504. In this disclosure, silicon steel is steel containing 1.0% to 5.0% by mass of silicon and less than or equal to 0.1% by mass of carbon, with the remainder being iron and unavoidable impurities. Alternatively, the silicon steel may also contain at least one of 0.01% to 1.2% by mass of manganese and 0.01% to 1.2% by mass of aluminum. The shape of the cross-section of the core wire portion 11 perpendicular to its longitudinal direction (the cross-sectional shape of the core wire portion 11) is not particularly limited; for example, it can be rectangular as in this embodiment. It should be noted that in this disclosure, a rectangle includes a square. The rectangular cross-sectional shape of the core wire portion 11 does not need to achieve, for example, that the outer peripheral surfaces at each vertex are perpendicular to each other in a strict sense. For example, chamfered portions may be formed in the region of the outer peripheral surface corresponding to each vertex. Curved surfaces with an arc shape may also be formed in the region of the outer peripheral surface corresponding to each vertex. The state in which the cross-sectional shape of the core wire portion 11 is rectangular refers to the following states: (1) In each side, the proportion of chamfered portions and curved surfaces formed at the corners is less than or equal to 20% (more preferably less than 20%), (2) The angle formed by opposite sides is less than or equal to 2° (preferably less than or equal to 0.3°), (3) Based on one side, the length of the other side opposite to that side is greater than or equal to 60% and less than or equal to 140% of the length of one side (preferably close to 100% of the length of one side).

[0046] Reference Figure 2 and Figure 3 Preferably, the height h of the cross-section of the core wire portion 11 perpendicular to the longitudinal direction and parallel to the central axis A is less than or equal to 0.6 mm. By reducing the height h to this level, the eddy current loss of the stator core 1 is reduced. As a result, the iron loss of the stator core 1 can be reduced. The width w of the cross-section of the core wire portion 11 perpendicular to the longitudinal direction and perpendicular to the central axis A can be appropriately determined according to the required characteristics of the stator core 1. The width w can be greater than or less than the height h. The width w can also be the same as the height h. That is, the cross-section of the core wire portion 11 perpendicular to the longitudinal direction can also be square.

[0047] [Insulating film 12] The insulating film 12 is configured to cover the outer peripheral surface of the core wire portion 11. Alternatively, the insulating film 12 may cover not only the outer peripheral surface of the core wire portion 11 but also the end face. The material constituting the insulating film 12 can be any insulating material and is not particularly limited; for example, it may be an inorganic material. From the viewpoints of insulation properties, cost, and ease of forming the insulating film, it is preferable that the material constituting the insulating film 12 is a phosphate. The phosphate is at least one selected from the group consisting of iron phosphate, zinc phosphate, and manganese phosphate. The material constituting the insulating film 12 may also be an oxide of the electromagnetic soft iron constituting the core wire portion 11 or an oxide of silicon steel. In other words, the insulating film 12 may also be an oxide film.

[0048] Reference Figure 1 and Figure 2 In a cross-section including the central axis A, the insulating films 12 covering adjacent core wire portions 11 in a direction parallel to the central axis A are in contact with each other. Alternatively, in a cross-section including the central axis A, the outer peripheral surfaces of adjacent insulating wires 10 are in contact with each other. Even if the insulating films 12 covering adjacent core wire portions 11 in a direction parallel to the central axis A are separated in a cross-section including the central axis A, the stator core 1 will still function. However, by having the insulating films 12 covering the core wire portions 11 in contact with each other, the maximum permeability of the stator core 1 can be increased.

[0049] Reference Figure 3 The thickness t of the insulating film 12 can be appropriately set according to the required characteristics of the stator core 1. However, from the viewpoint of ensuring sufficient insulation and high maximum permeability, it is preferable that the thickness t is greater than or equal to 0.1 μm and less than or equal to 30 μm, and more preferably that the thickness t is greater than or equal to 0.1 μm and less than or equal to 5 μm. As described above, the stator core 1 of this embodiment adopts a structure including a core wire portion 11 and an insulating film 12 covering the outer peripheral surface of the core wire portion 11, thereby achieving a stator core with reduced yield and improved manufacturing difficulty. The core wire portion 11 has a spiral shape and is made of metal wire made of electromagnetic soft iron or silicon steel.

[0050] Reference Figure 2 The length L of the stator core 1 in the direction parallel to the central axis A is greater than or equal to 50 mm, further, the length L is greater than or equal to 100 mm, and further, the length L is greater than or equal to 130 mm. If the length L of the stator core 1 in the direction parallel to the central axis A is within the above range, the motor 2 equipped with the stator core 1 can be improved (described later, see reference). Figure 7The torque of the stator core 1 is as follows: The upper limit of the length L in the direction parallel to the central axis A is not limited. The length L in the direction parallel to the central axis A of the stator core 1 is the average of the lengths L1 and L2 of two parts 180 degrees apart in the circumferential direction around the central axis A ((L1 + L2) / 2). The outer diameter D of the stator core 1 is less than or equal to 30 mm, and further, the outer diameter D is less than or equal to 20 mm. If the outer diameter D of the stator core 1 is within the above range, the motor 2 or generator 3 equipped with the stator core 1 can be miniaturized. The aspect ratio (L / D) of the ratio of the length L in the direction parallel to the central axis A of the stator core 1 to the outer diameter D of the stator core 1 is greater than or equal to 3, further, greater than or equal to 5, further, greater than or equal to 10, and further, greater than or equal to 15. If the aspect ratio is within the above range, both high torque and miniaturization of the motor 2 equipped with the stator core 1 can be achieved. The upper limit of the aspect ratio is not limited.

[0051] [The proportion of crystals in which the radial angle between the spiral in the core wire section 11 and the direction of iron

[100] is within 15 degrees (first proportion)] In the stator core 1, in the core wire section 11, the proportion of crystals whose radial direction of the helix forms an angle of 15 degrees or less with the direction of the iron

[100] is greater than or equal to 10%. Furthermore, the first proportion may be greater than or equal to 11% or greater than or equal to 12%. The first proportion may also be less than or equal to 30% or less than or equal to 20%. As described above, a high first proportion allows for a high degree of uniformity in the orientation of the crystals included in the core wire section 11. Consequently, the stator core 1 has a high saturation magnetic flux density and a high permeability. The first proportion is determined by EBSD (Electron Backscatter Diffraction) of the core wire section 11.

[0052] like Figure 1 As shown, the standard deviation of the first proportion of the first portion P1, the second portion P2, and the third portion P3 on the outer peripheral surface of the core wire portion 11 is less than or equal to 0.2%, or may be less than or equal to 0.1%. The second portion P2 is on the outer peripheral surface of the core wire portion 11, 120 degrees away from the first portion P1 in the circumferential direction around the central axis A. The third portion P3 is on the outer peripheral surface of the core wire portion 11, 120 degrees away from the first portion P1 and the second portion P2 in the circumferential direction around the central axis A.

[0053] [The proportion of crystals in which the radial angle between the helix in the core wire section 11 and the direction of iron

[100] is within 20 degrees (second proportion)] In the stator core 1, in the core wire section 11, the second proportion of crystals whose radial angle with the direction of the helix is ​​within 20 degrees to the direction of the iron

[100] is greater than or equal to 20%. Furthermore, the second proportion may be greater than or equal to 21% or greater than or equal to 22%. The second proportion may also be less than or equal to 40% or less than or equal to 30%. As described above, a high second proportion allows for a high degree of uniformity in the orientation of the crystals included in the core wire section. Consequently, the stator core 1 has a high saturation magnetic flux density and a high permeability. The second proportion is determined by the EBSD of the core wire section 11.

[0054] The standard deviation of the second proportion in the first part P1, the second part P2, and the third part P3 of the outer peripheral surface of the core wire section 11 is less than or equal to 0.2%, or it can be less than or equal to 0.1%.

[0055] [Manufacturing method of stator core 1] Next, an example of the manufacturing method of the stator core 1 in this embodiment will be described. Figure 4 This is a flowchart illustrating a general method for manufacturing the stator core 1 in this embodiment. (Refer to...) Figure 4 In the manufacturing method of the stator core 1 in this embodiment, firstly, as step S10, a raw material wire preparation step is performed. In this step S10, a raw material wire made of electromagnetic soft iron or silicon steel, which is to be used as the core wire portion 11, is prepared. The wire diameter of the raw material wire can be appropriately selected by considering the cross-sectional area of ​​the desired core wire portion 11 perpendicular to the longitudinal direction.

[0056] Next, as step S20, a forming process is performed. The raw material wire prepared in step S10 is subjected to forming processing. The forming process is not limited. Examples of forming processes include wire drawing and rolling. Wire drawing and rolling can be performed separately or together. For example, wire drawing is performed by passing the raw material wire through a through-hole formed in a die. Wire drawing can also be performed using multiple dies and through multiple processing steps. In this embodiment, the cross-sectional shape of the core wire portion 11 in the longitudinal direction is rectangular. Therefore, for example, a raw material wire with a circular cross-section perpendicular to the longitudinal direction is first prepared, and then processed into a metal wire with a circular cross-section and a smaller cross-sectional area perpendicular to the longitudinal direction compared to the raw material wire through one or more wire drawing processes. Afterwards, wire drawing (shaped processing) is performed using a die with a through-hole formed in the cross-section of a rectangle, thereby obtaining a metal wire with a rectangular cross-section perpendicular to the longitudinal direction. This metal wire becomes the core wire portion 11. For example, rolling is performed by passing the raw material wire through a roller. The area reduction rate in the above forming process can be set to be greater than or equal to 20% and less than or equal to 95%. It should be noted that magnetic annealing can also be performed after forming in process S20.

[0057] Next, as step S30, an insulating film forming process is performed. In this step S30, an insulating film 12 is formed on the outer peripheral surface of the metal wire with a rectangular cross-section perpendicular to the longitudinal direction obtained in step S20. If the material constituting the insulating film 12 is phosphate, a phosphate coating treatment is performed in step S30. If the material constituting the insulating film 12 is oxide, the core wire portion 11 after step S20 is placed in the atmosphere at room temperature (25°C) in step S30. The insulating film 12 may also be an oxide film that forms naturally (unintentionally) immediately after step S20. Thus, an insulating film 12 is formed on the outer peripheral surface of the electromagnetic soft iron or silicon steel metal wire obtained in step S20. As the insulating film for forming the insulating film 12, for example, a phosphate coating or an oxide film can be used. The electromagnetic soft iron or silicon steel metal wire obtained in step S20 becomes the core wire portion 11. As a result, an iron wire 10 with an insulating coating, including the core wire portion 11 and the insulating film 12, is obtained.

[0058] Next, as step S40, a winding process is performed. In this step S40, the iron wire 10 with an insulating film obtained in step S30 is processed into a spiral (coil) shape (winding process). The winding process can be performed, for example, by bending the iron wire 10 with an insulating film using a pin (processing using a spring coiling machine) or by winding the iron wire 10 with an insulating film around a shaft.

[0059] Next, as step S50, an annealing process is performed. In this step S50, the iron wire 10 with an insulating film, which has been processed into a spiral shape, is annealed. The annealing process can be performed, for example, by heating the iron wire 10 with an insulating film, which has been processed into a spiral shape, in an inert gas atmosphere such as nitrogen to a temperature range of 600°C or higher and 900°C or lower. From the viewpoint of stability of characteristics, it is preferable to hold the wire in this temperature range for a time of 5 minutes or higher and 60 minutes or lower. The holding time in this temperature range can also be less than 5 minutes, but since the characteristics of the stator core 1 are prone to instability, it is preferable to set the time to 5 minutes or higher. The holding time in this temperature range can also exceed 60 minutes, but from the viewpoint of productivity, it is preferable to set the time to 60 minutes or lower. Through the above process, the stator core 1 of this embodiment can be manufactured.

[0060] In the manufacturing method of the stator core 1 according to this embodiment, the formed wire is wound. Therefore, the first ratio can be increased to 10% or greater, or the second ratio can be increased to 20% or greater. As described above, the stator core 1 is manufactured by winding the formed wire, therefore, in each of the first portion P1, the second portion P2, and the third portion P3 in the core wire portion 11 of the stator core 1, the forming direction is consistent with the circumferential direction. Therefore, the standard deviation of the first ratio in the first portion P1, the second portion P2, and the third portion P3 can be reduced to less than or equal to 0.2%, and the standard deviation of the second ratio in the first portion P1, the second portion P2, and the third portion P3 can be reduced to less than or equal to 0.2%. As a result, the stator core 1 has a higher saturation magnetic flux density. Moreover, the stator core 1 has a higher permeability.

[0061] [Manufacturing method of the modified example] The position of step S30 is not limited to the above embodiment. Step S30 may also be performed in parallel with steps S20, S40 or S50. For example, when steps S30 and S50 are performed in parallel, when the core wire portion 11 is heated after step S40, an insulating film 12, which is a naturally formed oxide film, is formed on the outer peripheral surface of the core wire portion 11.

[0062] Although not shown, step S30 can be performed after step S10 and before step S20. Although not shown, step S30 can also be performed after step S40 and before step S50. Step S30 can also be performed after step S50.

[0063] [Stator core of the modified example] Reference Figures 5A to 5G The stator cores of the first to fifth modifications will be described. For example... Figures 5A to 5G As shown, the stator core 1, in addition to the core wire portion 11 and the insulating film 12, also includes a resin portion 13. The resin portion 13 coats the insulating film 12 that covers the core wire portion 11.

[0064] [First variation] Reference Figure 5A The stator core of the first modified example will be described. Figure 5A This is an enlarged cross-sectional view of a portion of the stator core in the first modified example. (See image.) Figure 5A As shown, in the first modified example, the resin part 13 includes a first part 131 and a third part 133.

[0065] In a cross-section including the central axis A, when viewed from the core wire portion 11, the first portion 131 is located on the side opposite to the central axis A. In a cross-section including the central axis A, the first portion 131 is located on the surface of the insulating film 12 that contacts the outer surface SA. The outer surface SA is the surface in the core wire portion 11 located on the side opposite to the central axis A. The first portion 131 has a cylindrical shape extending in a direction parallel to the central axis A.

[0066] The third part 133 is continuous with the first part 131. In a cross-section including the central axis A, the third part 133 is located between the insulating films 12 covering the core wire portions 11 adjacent to each other in a direction parallel to the central axis A. In a cross-section including the central axis A, the third part 133 is located between the insulating films 12 that respectively contact the two opposing surfaces S1. In a cross-section including the central axis A, the two opposing surfaces S1 are two surfaces of the core wire portions 11 that are adjacent to each other in a direction parallel to the central axis A and face each other. The third part 133 is filled between the insulating films 12 that respectively contact the two opposing surfaces S1. In a cross-section including the central axis A, the third part 133 faces the entire area of ​​the radially opposing surfaces S1.

[0067] The resin portion 13 is composed of a cured body 130. The cured body 130 bonds the insulating film 12 covering the core portions 11 that are adjacent to each other in a direction parallel to the central axis A. The cured body 130 is a cured product of an adhesive or a cured product of a coating, specifically, a cured product of an epoxy resin adhesive or a cured product of an epoxy resin coating.

[0068] The thickness (radial length) of the first part 131 is 10 μm to 40 μm. The thickness (length in the direction parallel to the central axis A) of the third part 133 is 10 μm to 40 μm.

[0069] The resin part 13 is formed between process S40 and process S50. After process S40, an adhesive or coating is applied to the iron wire 10 with an insulating film that has been processed into a spiral shape, and then the adhesive or coating is cured to form a cured body 130.

[0070] [Further variations of the first variation] Reference Figure 5B The stator core of a further modification of the first modification will be described. Figure 5B This is an enlarged cross-sectional view of a portion of the stator core in a further modification of the first modification. (See image.) Figure 5B As shown, in a further variation of the first variation, in the section containing the central axis A, the third part 133 is opposite to a radial portion of each of the two opposing surfaces S1.

[0071] The opposing surface S1 includes a first end S2 and a second end S3. In a section containing the central axis A, the first end S2 is the end of the opposing surface S1 that is away from the central axis A. In a section containing the central axis A, the second end S3 is the end of the opposing surface S1 that is close to the central axis A.

[0072] In this modified example, in the cross-section including the central axis A, the third part 133 is opposite to the first end S2. On the other hand, when viewed in a direction parallel to the central axis A, the third part 133 is offset from the second end S3.

[0073] [Second variation] Reference Figure 5C The stator core of the second modified example will be described. Figure 5C This is an enlarged cross-sectional view of a portion of the stator core in the second variation. (See image.) Figure 5C As shown, in the second modified example, the resin part 13 includes a first part 131 (see reference). Figure 5A On the other hand, resin part 13 does not include second part 132 (described later, see reference). Figure 5D ) and Part 3, Chapter 133 (see reference) Figure 5A ).

[0074] [Third variation] Reference Figure 5D The stator core of the third variation will be described. Figure 5D This is an enlarged sectional view of a portion of the stator core in the third variation. (See image.) Figure 5D As shown, in the third variation, the resin portion 13 includes a second portion 132. In a cross-section including the central axis A, the second portion 132 is located between the core portion 11 and the central axis A. Specifically, the second portion 132 is located on the surface of the insulating film 12 that contacts the inner surface SB. The inner surface SB is the surface of the core portion 11 opposite to the central axis A. The second portion 132 has a cylindrical shape extending in a direction parallel to the central axis A. The thickness (radial length) of the second portion 132 is 10 μm to 40 μm. On the other hand, the resin portion 13 does not include the first portion 131 (see reference). Figure 5A ) and Part 3, Chapter 133 (see reference) Figure 5A ).

[0075] [Further variations of the third variation] Reference Figure 5E The stator core of a further modification of the third modification will be described. Figure 5E This is an enlarged cross-sectional view of a portion of the stator core in a further modification of the third modification. (See image.) Figure 5EAs shown, in this modified example, the resin portion 13 includes a second portion 132 and a third portion 133. In this modified example, the third portion 133 is continuous with the second portion 132. In a cross-section including the central axis A, the third portion 133 is opposite to the second end portion S3. On the other hand, when viewed in a direction parallel to the central axis A, the third portion 133 is offset from the first end portion S2.

[0076] [Fourth variation] Reference Figure 5F The stator core of the fourth modified example will be described. Figure 5F This is an enlarged sectional view of a portion of the stator core in the fourth variation. (See image.) Figure 5F As shown, the resin part 13 includes a third part 133 (see reference). Figure 5A On the other hand, resin part 13 does not include first part 131 (see reference). Figure 5A ) and Part 132 (see reference) Figure 5E ).

[0077] [Fifth variation] Reference Figure 5G The stator core of the fifth variation will be described. Figure 5G This is an enlarged sectional view of a portion of the stator core in the fifth variation. (See example...) Figure 5G As shown, the resin portion 13 includes a first portion 131, a second portion 132, and a third portion 133. The third portion 133 is continuous with the first portion 131 and the second portion 132, respectively.

[0078] As can be seen from the first to the fifth modifications described above, the resin part 13 may include at least one of the group consisting of the first part 131, the second part 132 and the third part 133.

[0079] [Electric motors and generators] Reference Figure 6 and Figure 7 The embodiments of the electric motor disclosed herein will be described. Figure 6 This is a perspective view of the electric motor and generator in this embodiment. Figure 7 It is along Figure 1 A cross-sectional view along the XX line.

[0080] like Figure 6 and Figure 7 As shown, the electric motor 2 includes a housing 21, a shaft 22, a rotor 23, a stator core 1, and a coil 24. The housing 21 has a cylindrical shape, wherein the cylindrical shape has a shaft B. The housing 21 houses a portion of the shaft 22, the rotor 23, the stator core 1, and the coil 24. The shaft 22 has a common shaft B with the housing 21. The shaft 22 rotates about the shaft B relative to the housing 21. The end 221 of the shaft 22 in a direction parallel to the shaft B is located outside the housing 21.

[0081] Rotor 23 is fixed to a portion of shaft 22. Rotor 23 shares a common shaft B with shaft 22. Rotor 23 rotates together with shaft 22 about shaft B. Rotor 23 is composed of permanent magnets. Stator core 1 is fixed to the inner surface of housing 21. Stator core 1 is located radially outward of rotor 23. Stator core 1 is located away from the outer peripheral surface of rotor 23. Rotor 23 rotates relative to stator core 1. The central axis A of stator core 1 coincides with the axis B of rotor 23. Coil 24 is located between rotor 23 and stator core 1. Coil 24 is located away from the outer peripheral surface of rotor 23. Coil 24 is fixed to the inner surface 111 of stator core 1.

[0082] The generator 3 has the same structure as the electric motor 2. That is, the generator 3 has a housing 21, a shaft 22, a rotor 23, a stator core 1, and a coil 24.

[0083] Example The stator core 1 of each of samples A to C is manufactured according to a manufacturing method of one embodiment (see reference). Figure 1 The stator core 1 of sample D is manufactured by punching an electromagnetic steel plate 100 (see reference). Figure 8 Samples A through C are examples. Sample D is a comparative example. The manufacturing process of each of samples A through D will be described.

[0084] [Manufacturing of Sample A] First, the stator core 1 is manufactured through processes S10 to S50, which are the same as those in the embodiment described above. The width w of the core wire portion 11 is set to 1.0 mm, the height h is set to 1.7 mm, the thickness t of the insulating film 12 is set to 1 to 3 μm, the outer diameter D of the stator core 1 is set to 19.6 mm, and the inner diameter is set to 17.6 mm. The annealing temperature in process S50 is set to 600°C.

[0085] Crystal orientation analysis using EBSD was performed on the core portion 11 of the obtained sample A. The conditions for EBSD are shown below.

[0086] Apparatus: ZEISS Gemini 450 and Oxford Symmetry Accelerating voltage: 15kV, Irradiation current: 22nA, Analysis area: x200 (1μm step) Sample pretreatment: After resin embedding and mechanical grinding, cross-section machining is performed using argon ion polishing (CP). It should be noted that the above are the conditions for EBSD in this embodiment, and the conditions for EBSD are not limited to those described above.

[0087] As a result, the first proportion of each of the first portion P1, the second portion P2, and the third portion P3 of the core wire section 11 is 14.7%. The second proportion of each of the first portion P1, the second portion P2, and the third portion P3 of the core wire section 11 is 22.7%. The results of EBSD are recorded in Table 1.

[0088] [Manufacturing of Sample B] The stator core 1 of sample B was manufactured in the same manner as sample A. However, the annealing temperature in process S50 was changed from 600°C to 700°C. The EBSD results show that the first proportion of each of the first portion P1, the second portion P2, and the third portion P3 of the core wire portion 11 is 15.7%. Furthermore, the second proportion of each of the first portion P1, the second portion P2, and the third portion P3 of the core wire portion 11 is 23.6%. The EBSD results are shown in Table 1.

[0089] [Manufacturing of Sample C] The stator core 1 of sample C was manufactured in the same manner as sample A. However, the annealing temperature in process S50 was changed from 600°C to 710°C. The EBSD results show that the first proportion of each of the first portion P1, the second portion P2, and the third portion P3 of the core wire section 11 is 12.1%. The second proportion of each of the first portion P1, the second portion P2, and the third portion P3 of the core wire section 11 is 23.7%. The EBSD results are shown in Table 1.

[0090] [Manufacturing of Sample D] Figure 8 This is a top view of the stator core of sample D, manufactured by punching an electromagnetic steel sheet. (Example:) Figure 8 As shown, multiple electromagnetic steel plates 100 are punched into ring shapes, and these electromagnetic steel plates 100 are stacked to form the core wire portion 11. Then, processes S30 and S50, identical to those in sample A, are performed sequentially. This produces the stator core 1.

[0091] The EBSD results show that the first proportion in the first portion P1 of the core wire section 11 is 8.9%. The first proportion in the fourth portion P4 of the core wire section 11 is 8.3%. The fourth portion P4 is 90 degrees away from the first portion P1 in the circumferential direction around the central axis A. The standard deviation between the first proportion in the first portion P1 and the first proportion in the fourth portion P4 is 0.3%.

[0092] The second proportion in the first part P1 of the core wire section 11 is 15.9%. The second proportion in the fourth part P4 of the core wire section 11 is 15.1%. The standard deviation between the second proportion in the first part P1 and the second proportion in the fourth part P4 is 0.4%. The results of EBSD are recorded in Table 1.

[0093] [Table 1] It should be understood that the embodiments and examples disclosed herein are illustrative in all respects and not intended to limit in any way. The scope of the invention is not defined by the foregoing description but by the claims, which are intended to include all modifications within the meaning and scope equivalent to the claims.

[0094] Explanation of reference numerals in the attached figures: 1: Stator core; 2: Motor; 3: Generator; 10: Iron wire with insulating film; 11: Core wire section; 12: Insulating film; 13: Resin section; 21: Housing; 22: Shaft; 23: Rotor; 24: Coil; 111: Inner surface; 130: Cured body; 131: First part; 132: Second part; 133: Third part; 221: End; A: Central shaft; B: Shaft; L: Length of the stator core in the direction parallel to the central shaft; L1, L2: Lengths of two parts 180 degrees apart in the circumferential direction around the central shaft; D: Outer diameter; P1: First part; P2: Second part; P3: Third part; P4: Fourth part; S1: Opposing surface; S2: First end; S3: Second end; SA: Outer surface; SB: Inner surface; h: Height; r: Distance; t: Thickness; w: Width.

Claims

1. A stator core, comprising: The core wire portion has a helical shape with a constant distance from the central axis, and the core wire portion is made of electromagnetic soft iron or silicon steel wire; and An insulating film covers the outer peripheral surface of the core wire portion. In the core section, the proportion of crystals whose radial angle with the direction of the helix is ​​within 15 degrees is greater than or equal to 10%.

2. The stator core according to claim 1, wherein, The standard deviation of the first proportion in the first, second, and third portions of the outer peripheral surface is less than or equal to 0.2%, wherein the second portion is the portion 120 degrees away from the first portion in the circumferential direction about the central axis, and the third portion is the portion 120 degrees away from the first and second portions in the circumferential direction about the central axis.

3. A stator core, comprising: The core wire portion has a helical shape with a constant distance from the central axis, and the core wire portion is made of electromagnetic soft iron or silicon steel wire; and An insulating film covers the outer peripheral surface of the core wire portion. In the core section, the second proportion of crystals whose radial angle with the direction of the helix is ​​within 20 degrees is greater than or equal to 20%.

4. The stator core according to claim 3, wherein, The standard deviation of the second proportion in the first, second, and third portions of the outer peripheral surface is less than or equal to 0.2%, wherein the second portion is the portion 120 degrees away from the first portion in the circumferential direction about the central axis, and the third portion is the portion 120 degrees away from the first and second portions in the circumferential direction about the central axis.

5. The stator core according to any one of claims 1 to 4, wherein, In a cross-section containing the central axis, the insulating films covering the core wire portions adjacent to each other in a direction parallel to the central axis are in contact with each other.

6. The stator core according to any one of claims 1 to 4, wherein, The stator core also includes a resin portion covering the insulating film. In a cross-section including the central axis, the resin portion includes at least one selected from the group consisting of the first portion, the second portion, and the third portion, wherein, The first part covers the insulating film located on the side opposite to the central axis when viewed from the core wire portion. The second part covers the insulating film located between the core wire portion and the central axis. The third part is located between the insulating films covering the core wire portions that are adjacent to each other in a direction parallel to the central axis.

7. The stator core according to claim 6, wherein, The resin portion is a cured body that bonds the insulating film covering the core wire portions that are adjacent to each other in a direction parallel to the central axis.

8. The stator core according to any one of claims 1 to 7, wherein, The cross-section of the core wire portion perpendicular to the longitudinal direction is rectangular.

9. The stator core according to any one of claims 1 to 8, wherein, The height of the core wire portion in the cross section perpendicular to the longitudinal direction and in the direction parallel to the central axis is less than or equal to 0.6 mm.

10. The stator core according to any one of claims 1 to 9, wherein, The insulating film is made of inorganic materials.

11. The stator core according to claim 10, wherein, The inorganic material is phosphate.

12. The stator core according to any one of claims 1 to 11, wherein, The thickness of the insulating film is greater than or equal to 0.1 μm and less than or equal to 30 μm.

13. The stator core according to any one of claims 1 to 12, wherein, The aspect ratio of the length of the stator core in the direction parallel to the central axis to the outer diameter of the stator core is greater than or equal to 3.

14. An electric motor comprising a stator core as described in any one of claims 1 to 13.

15. A generator comprising a stator core as described in any one of claims 1 to 13.

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