Stator core, electric motor, and generator

Abstract

This stator core has a spiral shape in which the distance from the central axis is constant, and comprises: a core wire part composed of a wire made of electromagnetic soft iron or silicon steel; and an insulating film covering the outer peripheral surface of the core wire part. A first ratio, which is the ratio of crystals of which the angle formed by the radial direction of the spiral and the iron [100] direction is within 15 degrees, is at least 10%.

Description

Stator cores, electric motors and generators

[0001] This disclosure relates to a stator core, an electric motor, and a generator. This application claims priority to Japanese Application No. 2023-199294, filed November 24, 2023, and incorporates by reference all of the contents of said Japanese application.

[0002] A stator core having a spiral shape with a constant distance from a 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] JP 2024-13954 A

[0004] A stator core according to the present disclosure has a spiral shape with a constant distance from a central axis, and includes a core portion made of soft electromagnetic iron or silicon steel wire, and an insulating film covering the outer surface of the core portion. A first ratio, which is the ratio of crystals whose angle between the radial direction of the spiral and the iron

[100] direction is 15 degrees or less, is 10% or more.

[0005] FIG. 1 is a schematic perspective view showing the structure of a stator core according to the present embodiment. FIG. 2 is a view corresponding to a cross section including the central axis A of FIG. 1 (a cross section taken along line II-II in FIG. 1). FIG. 3 is a schematic cross-sectional view showing the structure of a core portion and an insulating film that constitute the stator core. FIG. 4 is a flowchart showing an outline of a method for manufacturing a stator core. FIG. 5A is an enlarged cross-sectional view of a portion of a stator core according to a first modified example. FIG. 5B is an enlarged cross-sectional view of a portion of a stator core according to a further modified example of the first modified example. FIG. 5C is an enlarged cross-sectional view of a portion of a stator core according to a second modified example. FIG. 5D is an enlarged cross-sectional view of a portion of a stator core according to a third modified example. FIG. 5E is an enlarged cross-sectional view of a portion of a stator core according to a further modified example of the third modified example. FIG. 5F is an enlarged cross-sectional view of a portion of a stator core according to a fourth modified example. FIG. 5G is an enlarged cross-sectional view of a portion of a stator core according to a fifth modified example. FIG. 6 is a perspective view of an electric motor and a generator according to the present embodiment. FIG. 7 is a cross-sectional view taken along line XX in FIG. 6. FIG. 8 is a plan view of a stator core of sample D manufactured by punching an electromagnetic steel sheet.

[0006] [Problem to be Solved by the Present Disclosure] The stator core disclosed in the above-mentioned Patent Document 1 has a low saturation magnetic flux density. One of the objects of the present disclosure is to provide a stator core with a high saturation magnetic flux density.

[0007] [Advantages of the Present Disclosure] The stator core of the present disclosure can provide a stator core having a high saturation magnetic flux density.

[0008] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be described. (1) A stator core of the present disclosure has a spiral shape with a constant distance from a central axis, and includes a core portion made of a wire made of soft magnetic iron or silicon steel, and an insulating film covering the outer surface of the core portion. In the core portion, a first ratio, which is the ratio of crystals in which the angle between the radial direction of the spiral and the iron

[100] direction is within 15 degrees, is 10% or more.

[0009] In this stator core, the first ratio is as high as 10% or more. By aligning the orientation of the crystals contained in the core portion to this extent, a stator core having a high saturation magnetic flux density can be obtained.

[0010] (2) In (1) above, the standard deviation of the second ratio in a first portion of the outer peripheral surface, a second portion 120 degrees circumferentially spaced from the first portion around the central axis, and a third portion 120 degrees circumferentially spaced from the first portion and the second portion around the central axis may be 0.2% or less.

[0011] In electrical steel sheets, the crystal orientation is aligned so that a specific crystal plane faces the rolling direction. Therefore, in a stator core manufactured by punching out annular sheets from electrical steel sheets and laminating them, even if the rolling direction and the circumferential direction coincide in the first section, the rolling direction and the circumferential direction do not coincide in the second and third sections, which are 120 degrees away from the first section 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 spiral and the iron

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

[100] direction will inevitably be low in the second and third sections.

[0012] In contrast, if the formed wire is coiled, the forming direction and the circumferential direction of the first, second, and third sections of the core wire of the stator core will coincide, resulting in a higher proportion of crystals with a small angle between the radial direction of the spiral and the iron

[100] direction.

[0013] (3) A stator core according to the present disclosure has a spiral shape with a constant distance from a central axis, and includes a core portion made of soft electromagnetic iron or silicon steel wire, and an insulating film covering the outer surface of the core portion. The insulating film covers the outer surface of the core portion. A second ratio, which is the ratio of crystals whose angle between the radial direction of the spiral and the iron

[100] direction is within 20 degrees, is 20% or more.

[0014] In this stator core, the second ratio is as high as 20% or more. By aligning the orientation of the crystals contained in the core portion to this extent, a stator core having a high saturation magnetic flux density can be obtained.

[0015] (4) In the above (3), the standard deviation of the second ratio in the first portion of the outer peripheral surface, the second portion 120 degrees circumferentially away from the first portion around the central axis, and the third portion 120 degrees circumferentially away from the first and second portions around the central axis may be 0.2 or less. For example, if the formed wire is coiled, the rolling direction and the circumferential direction of the first, second, and third portions of the core wire portion of the stator core coincide. Therefore, the proportion of crystals with a small angle between the radial direction of the spiral and the iron

[100] direction increases.

[0016] (5) In any one of (1) to (4) above, in a cross section including the central axis, insulating films covering adjacent core wire portions in a direction parallel to the central axis may be in contact with each other. This configuration can achieve a further reduction in iron loss.

[0017] (6) In any one of (1) to (4) above, the stator core may further include a resin portion covering the insulating film, and in a cross section including the central axis, the resin portion may include at least one selected from the group consisting of a first portion covering the insulating film located on the opposite side of the central axis as viewed from the core portion, a second portion covering the insulating film located between the core portion and the central axis, and a third portion located between the insulating films covering adjacent core portions in a direction parallel to the central axis. This configuration can improve the insulation of the core portion.

[0018] (7) In the above (6), the resin portion may be a hardened body that bonds the insulating film that covers the adjacent core wire portions in a direction parallel to the central axis. This configuration can improve the stability of the shape of the insulating-coated iron wire including the first portion, the second portion, and the insulating film.

[0019] (8) In any one of (1) to (7) above, the cross section of the core wire perpendicular to the longitudinal direction may be rectangular. This configuration reduces the space between adjacent core wires in the direction parallel to the central axis. As a result, further improvements in maximum magnetic permeability and saturation magnetic flux density can be achieved.

[0020] (9) In any one of (1) to (8) above, a height of the core portion in a direction parallel to the central axis of a cross section perpendicular to the longitudinal direction of the core portion may be 0.6 mm or less. With this configuration, eddy current loss is reduced, and as a result, iron loss can be reduced.

[0021] (10) In any one of the above (1) to (9), the insulating film may be made of an inorganic material. Inorganic materials are suitable as materials for the insulating film covering the core portion.

[0022] (11) In the above (10), the inorganic material may be a phosphate. Phosphate is particularly suitable as a material for the insulating film covering the core wire from the viewpoints of insulating properties, cost, ease of forming the insulating film, etc.

[0023] (12) In any one of (1) to (11) above, the thickness of the insulating film may be 0.1 μm or more and 30 μm or less. If the thickness of the insulating film is less than 0.1 μm, there is a risk of insufficient insulation between adjacent core wires in a direction parallel to the central axis. On the other hand, if the thickness of the insulating film exceeds 30 μm, there is a risk of insufficient maximum magnetic permeability. Therefore, it is preferable that the thickness of the insulating film be within the above range. From the viewpoint of ensuring higher maximum magnetic permeability and saturation magnetic flux density, it is more preferable that the thickness of the insulating film be 5 μm or less.

[0024] (13) In any one of (1) to (12) above, the aspect ratio, which is the ratio of the length of the stator core in a direction parallel to the central axis thereof to the outer diameter thereof, may be equal to or greater than 3. This configuration can increase the torque of an electric motor equipped with the stator core, or can increase the power generation performance of a generator equipped with the stator core while miniaturizing the electric motor or generator.

[0025] (14) An electric motor according to the present disclosure includes the stator core according to any one of (1) to (13) above. This electric motor has a stator core with a high maximum magnetic permeability, and therefore has high torque.

[0026] (15) A generator according to the present disclosure includes the stator core according to any one of (1) to (13) above. Since the generator includes a stator core having a high maximum magnetic permeability, the generator has high power generation efficiency.

[0027] [Details of the embodiment of the present disclosure] Next, an embodiment of the stator core of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0028] Fig. 1 is a schematic perspective view showing the structure of a stator core in this embodiment. Fig. 2 is a view corresponding to a cross section including the central axis A of Fig. 1 (a cross section taken along line II-II in Fig. 1). Fig. 3 is a schematic cross section showing the structure of the core wire portion and insulating film that constitute the stator core.

[0029] 1, stator core 1 in this embodiment has a structure in which insulating coated iron wire 10 is wound in a spiral shape at a constant distance from central axis A. Referring to Fig. 1 and Fig. 2, stator core 1 includes core wire portion 11 and insulating film 12. Core wire portion 11 and insulating film 12 constitute insulating coated iron wire 10.

[0030] [Core Wire Portion 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 composed of a wire made of electromagnetic soft iron or silicon steel. In this disclosure, electromagnetic soft iron refers to electromagnetic soft iron as defined in JIS standard C2504. In this disclosure, silicon steel is steel containing 1.0 to 5.0% by mass of silicon and 0.1% or less by mass of carbon, with the remainder being iron and unavoidable impurities. The silicon steel may further 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 cross-sectional shape of the core wire portion 11 perpendicular to the longitudinal direction (cross-sectional shape of the core wire portion 11) is not particularly limited, but may be rectangular, as in the present embodiment. Note that in this disclosure, a rectangle also includes a square. The cross-sectional shape of the core wire portion 11 does not necessarily mean that the outer peripheral surfaces are strictly perpendicular to each other at each vertex. For example, chamfered portions may be formed in the regions of the outer peripheral surface corresponding to each vertex. The regions of the outer peripheral surface corresponding to each vertex may also have curved portions with an arc-like shape. The cross-sectional shape of the core wire portion 11 means that (1) the chamfered portions and curved portions formed at the corners of each side occupy 20% or less (preferably a small proportion), (2) the angle between opposing sides is 2° or less (preferably 0.3° or less), and (3) the length of one side relative to the other side is 60% to 140% of the length of the other side (preferably close to 100%).

[0031] 2 and 3, the height h of the core wire portion 11 in a cross section perpendicular to the longitudinal direction, in a direction parallel to the central axis A, is preferably 0.6 mm or less. Reducing the height h to this level reduces eddy current loss in the stator core 1. As a result, iron loss in the stator core 1 can be reduced. The width w of the core wire portion 11 in a cross section perpendicular to the longitudinal direction, in a direction perpendicular to the central axis A, can be appropriately determined depending on the characteristics required of the stator core 1. The width w may be greater or smaller than the height h. The width w may be the same as the height h. In other words, the cross section perpendicular to the longitudinal direction of the core wire portion 11 may be square.

[0032] [Insulating Film 12] The insulating film 12 is disposed so as to cover the outer peripheral surface of the core wire portion 11. The insulating film 12 may cover the end surfaces of the core wire portion 11 in addition to the outer peripheral surface. The material constituting the insulating film 12 is not particularly limited as long as it has insulating properties, but may be, for example, an inorganic material. From the viewpoints of insulating properties, cost, ease of insulating film formation, etc., the material constituting the insulating film 12 is preferably 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 be an oxide of the soft magnetic iron or silicon steel constituting the core wire portion 11. In other words, the insulating film 12 may be an oxide film.

[0033] 1 and 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. From another perspective, in a cross section including the central axis A, the outer circumferential surfaces of adjacent insulating-coated iron wires 10 are in contact with each other. Even if, 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 separated from each other, the stator core 1 still functions. However, by bringing the insulating films 12 covering the core wire portions 11 into contact with each other, the maximum magnetic permeability of the stator core 1 can be improved.

[0034] 3, the thickness t of insulating film 12 can be set appropriately depending on the characteristics required of stator core 1. However, from the viewpoint of ensuring both sufficient insulation and high maximum magnetic permeability, it is preferable to set the thickness to 0.1 μm or more and 30 μm or less, and further 0.1 μm or more and 5 μm or less. As described above, stator core 1 of the present embodiment employs a structure including core portion 11 having a spiral shape and made of a wire made of electromagnetic soft iron or silicon steel, and insulating film 12 covering the outer surface of core portion 11, thereby providing a stator core in which reduced yields and difficulty in manufacturing are improved.

[0035] Referring to FIG. 2 , the length L of the stator core 1 in a direction parallel to the central axis A is 50 mm or more, further 100 mm or more, and further 130 mm or more. If the length L of the stator core 1 in a direction parallel to the central axis A is within the above-mentioned range, the torque of an electric motor 2 (described later, see FIG. 7 ) including the stator core 1 can be increased. There is no upper limit to the length L of the stator core 1 in a direction parallel to the central axis A. The length L of the stator core 1 in a direction parallel to the central axis A is the average ((L1 + L2) / 2) of lengths L1 and L2 at two locations 180 degrees apart in the circumferential direction around the central axis A. The outer diameter D of the stator core 1 is 30 mm or less, further 20 mm or less. If the outer diameter D of the stator core 1 is within the above-mentioned range, the electric motor 2 or generator 3 including the stator core 1 can be made smaller. The aspect ratio (L / D), which is the ratio of the length L of the stator core 1 in a direction parallel to the central axis A to the outer diameter D of the stator core 1, is 3 or more, preferably 5 or more, further 10 or more, or even 15 or more. If the aspect ratio is within the above range, it is possible to achieve both high torque and compactness in the electric motor 2 equipped with the stator core 1. There is no upper limit to the aspect ratio.

[0036] [Proportion (First Proportion) of Crystals in the Core Wire Portion 11 in Which the Angle Between the Radial Direction of the Helix and the Iron

[100] Direction is 15° or Less] In the stator core 1, the first proportion, which is the proportion of crystals in the core wire portion 11 in Which the angle between the radial direction of the helix and the iron

[100] direction is 15° or less, is 10% or more. The first proportion may be 11% or more, or 12% or more. The first proportion may be 30% or less, or 20% or less. As described above, a high first proportion allows the crystals in the core wire portion 11 to be oriented in the same direction at a high rate. This allows the stator core 1 to have a high saturation magnetic flux density and a high magnetic permeability. The first proportion is determined by EBSD (Electron Backscatter Diffraction) of the core wire portion 11.

[0037] 1 , the standard deviation of the first ratio in the first portion P1, the second portion P2, and the third portion P3 on the outer circumferential surface of the core wire portion 11 is 0.2% or less, and may be 0.1% or less. The second portion P2 is spaced 120 degrees from the first portion P1 in the circumferential direction about the central axis A on the outer circumferential surface of the core wire portion 11. The third portion P3 is spaced 120 degrees from the first portion P1 and the second portion P2 in the circumferential direction about the central axis A on the outer circumferential surface of the core wire portion 11.

[0038] [Proportion of crystals in the core wire portion 11 where the angle between the radial direction of the spiral and the iron

[100] direction is 20 degrees or less (second proportion)] In the stator core 1, the second proportion, which is the proportion of crystals in the core wire portion 11 where the angle between the radial direction of the spiral and the iron

[100] direction is 20 degrees or less, is 20% or more. The second proportion may also be 21% or more, or 22% or more. The second proportion may be 40% or less, or 30% or less. As described above, a high second proportion allows the crystals in the core wire portion to be oriented in the same direction at a high rate. This allows the stator core 1 to have a high saturation magnetic flux density and also a high magnetic permeability. The second proportion can be determined by EBSD of the core wire portion 11.

[0039] The standard deviation of the second ratio in the first portion P1, the second portion P2, and the third portion P3 of the outer circumferential surface of the core portion 11 may be 0.2% or less, or 0.1% or less.

[0040] [Method for Manufacturing Stator Core 1] Next, an example of a method for manufacturing the stator core 1 according to the present embodiment will be described. FIG. 4 is a flowchart showing an outline of the method for manufacturing the stator core 1 according to the present embodiment. Referring to FIG. 4, in the method for manufacturing the stator core 1 according to the present embodiment, a raw material wire preparation step is first carried out as step S10. In step S10, a raw material wire made of soft magnetic iron or silicon steel to become the core portion 11 is prepared. The wire diameter of the raw material wire can be appropriately selected taking into consideration the cross-sectional area of ​​the desired core portion 11 in a cross section perpendicular to the longitudinal direction, etc.

[0041] Next, a forming step is performed as step S20. The raw wire prepared in step S10 is formed. The forming step is not limited. Examples of forming steps include wire drawing and rolling. Wire drawing and rolling may be performed independently or in combination. For example, wire drawing is performed by passing the raw wire through a through hole formed in a die. Wire drawing may be performed multiple times using multiple dies. In this embodiment, the cross section of the core wire portion 11 in the longitudinal direction is rectangular. Therefore, for example, a raw wire having a circular cross section perpendicular to the longitudinal direction is first prepared, and then the raw wire is drawn once or multiple times to form a wire having a circular cross section whose cross-sectional area perpendicular to the longitudinal direction is smaller than that of the raw wire. Then, wire drawing is performed using a die having a through hole with a rectangular cross section (deformed shape processing) to obtain a wire having a rectangular cross section perpendicular to the longitudinal direction. This wire becomes the core wire portion 11. For example, the rolling process is performed by passing the raw wire through rollers. The area reduction rate in the forming process can be, for example, 20% to 95%. In step S20, magnetic annealing may be performed after the forming process.

[0042] Next, an insulating film forming step is performed as step S30. In step S30, an insulating film 12 is formed on the outer surface of the wire obtained in step S20, which has a rectangular cross section perpendicular to the longitudinal direction. 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, in step S30, the core wire portion 11 after step S20 is left in the air at room temperature (25°C). The insulating film 12 may be an oxide film that is naturally (unintentionally) formed immediately after step S20. As a result, the insulating film 12 is formed on the outer surface of the soft magnetic iron or silicon steel wire obtained in step S20. For example, a phosphate coating or an oxide film can be used as the insulating film forming the insulating film 12. The soft magnetic iron or silicon steel wire obtained in step S20 becomes the core wire portion 11. As a result, an iron wire 10 with an insulating coating is obtained, which includes the core wire portion 11 and the insulating film 12.

[0043] Next, a coiling step is carried out as step S40. In this step S40, the iron wire 10 with the insulating coating obtained in step S30 is processed into a spiral (coil) shape (coiling process). The coiling process can be carried out, for example, by bending the iron wire 10 with a pin (processing using a coiling machine) or by winding the iron wire 10 with the insulating coating around a shaft.

[0044] Next, an annealing step is performed as step S50. In step S50, the spirally formed iron wire 10 with the insulating coating is annealed. The annealing step can be performed, for example, by heating the spirally formed iron wire 10 with the insulating coating to a temperature range of 600°C to 900°C in an inert gas atmosphere such as a nitrogen atmosphere. From the viewpoint of characteristic stability, it is preferable to hold the iron wire 10 in this temperature range for 5 minutes to 60 minutes. While the holding time in this temperature range may be less than 5 minutes, it is preferable to hold the iron wire 1 in this temperature range for 5 minutes or more because the characteristics of the stator core 1 tend to become unstable. Although the holding time in this temperature range may exceed 60 minutes, it is preferable to hold the iron wire 1 in this temperature range for 60 minutes or less from the viewpoint of productivity. The stator core 1 of the present embodiment can be manufactured by the above procedure.

[0045] In the manufacturing method of the stator core 1 of this embodiment, the formed wire is coiled. Therefore, the first ratio can be as high as 10% or more, or the second ratio can be as high as 20% or more. As described above, since the stator core 1 is manufactured by coiling the formed wire, the forming direction and the circumferential direction are aligned in the first portion P1, the second portion P2, and the third portion P3 of the core portion 11 of the stator core 1. 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 0.2% or less, 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 0.2% or less. As a result, the stator core 1 has a higher saturation magnetic flux density. Furthermore, the stator core 1 has a higher magnetic permeability.

[0046] [Manufacturing Method of Modified Example] The position of step S30 is not limited to that of the above embodiment. Step S30 may be performed in parallel with step S20, step S40, or step S50. For example, when step S30 is performed in parallel with step S50, an insulating film 12, which is a naturally formed oxide film, is formed on the outer peripheral surface of the core wire portion 11 when the core wire portion 11 is heated after step S40. Although not shown, step S30 may be performed after step S10 and before step S20. Although not shown, step S30 may be performed after step S40 and before step S50. Step S30 may be performed after step S50.

[0047] [Modified Stator Cores] Stator cores according to first to fifth modified examples will be described with reference to Figures 5A to 5G. As shown in Figures 5A to 5G, the stator core 1 includes a resin portion 13 in addition to the core portion 11 and the insulating film 12. The resin portion 13 covers the insulating film 12 that covers the core portion 11.

[0048] [First Modification] A stator core of a first modification will be described with reference to Fig. 5A. Fig. 5A is an enlarged cross-sectional view of a portion of the stator core in the first modification. As shown in Fig. 5A, in the first modification, the resin portion 13 includes a first portion 131 and a third portion 133.

[0049] In a cross section including the central axis A, the first portion 131 is located on the opposite side of the central axis A from the core portion 11. 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 of the core portion 11 that is located on the opposite side of the central axis A. The first portion 131 has a cylindrical shape that extends in a direction parallel to the central axis A.

[0050] The third portion 133 is continuous with the first portion 131. In a cross section including the central axis A, the third portion 133 is located between the insulating films 12 that cover adjacent core portions 11 in a direction parallel to the central axis A. In a cross section including the central axis A, the third portion 133 is located between the insulating films 12 that contact each of the two opposing surfaces S1. In a cross section including the central axis A, the two opposing surfaces S1 are two surfaces where adjacent core portions 11 in a direction parallel to the central axis A face each other. The third portion 133 is filled between the insulating films 12 that contact each of the two opposing surfaces S1. In a cross section including the central axis A, the third portion 133 faces the entire opposing surface S1 in the radial direction.

[0051] The resin portion 13 is composed of a cured body 130. The cured body 130 bonds the insulating films 12 that cover 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 paint, and more specifically, a cured product of an epoxy resin adhesive or a cured product of an epoxy resin paint.

[0052] The thickness (length in the radial direction) of the first portion 131 is 10 μm to 40 μm, and the thickness (length in the direction parallel to the central axis A) of the third portion 133 is 10 μm to 40 μm.

[0053] The resin portion 13 is formed between step S40 and step S50. After step S40, adhesive or paint is applied to the insulating coated iron wire 10 processed into a spiral shape, and then the adhesive or paint is cured to form a cured body 130.

[0054] [Further Modification of First Modification] A stator core according to a further modification of the first modification will be described with reference to Fig. 5B. Fig. 5B is an enlarged cross-sectional view of a portion of the stator core according to the further modification of the first modification. As shown in Fig. 5B, in this further modification of the first modification, the third portion 133 faces a radial portion of each of the two opposing surfaces S1 in a cross section including the central axis A.

[0055] The opposing surface S1 includes a first end S2 and a second end S3. In a cross section including the central axis A, the first end S2 is an end of the opposing surface S1 that is far from the central axis A. In a cross section including the central axis A, the second end S3 is an end of the opposing surface S1 that is close to the central axis A.

[0056] In this modified example, the third portion 133 faces the first end S2 in a cross section including the central axis A. On the other hand, when viewed in a direction parallel to the central axis A, the third portion 133 is misaligned with the second end S3.

[0057] [Second Modification] A stator core according to a second modification will be described with reference to Fig. 5C. Fig. 5C is an enlarged cross-sectional view of a portion of the stator core according to the second modification. As shown in Fig. 5C, in the second modification, the resin portion 13 includes a first portion 131 (see Fig. 5A). On the other hand, the resin portion 13 does not include a second portion 132 (described later, see Fig. 5D) or a third portion 133 (see Fig. 5A).

[0058] [Third Modification] A stator core according to a third modification will be described with reference to FIG. 5D . FIG. 5D is an enlarged cross-sectional view of a portion of the stator core according to the third modification. As shown in FIG. 5D , in the third modification, 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 that faces the central axis A. The second portion 132 has a cylindrical shape that extends in a direction parallel to the central axis A. The thickness (radial length) of the second portion 132 is 10 μm to 40 μm. Meanwhile, the resin portion 13 does not include the first portion 131 (see FIG. 5A ) or the third portion 133 (see FIG. 5A ).

[0059] [Further Modification of the Third Modification] A stator core according to a further modification of the third modification will be described with reference to Fig. 5E. Fig. 5E is an enlarged cross-sectional view of a portion of a stator core according to the further modification of the third modification. As shown in Fig. 5E, in this modification, the resin portion 13 includes a third portion 133 in addition to the second portion 132. In this modification, the third portion 133 is continuous with the second portion 132. In a cross section including the central axis A, the third portion 133 faces the second end S3. On the other hand, when viewed in a direction parallel to the central axis A, the third portion 133 is misaligned with the first end S2.

[0060] [Fourth Modification] A stator core according to a fourth modification will be described with reference to Fig. 5F. Fig. 5F is an enlarged cross-sectional view of a portion of the stator core according to the fourth modification. As shown in Fig. 5F, the resin portion 13 includes the third portion 133 (see Fig. 5A). On the other hand, the resin portion 13 does not include the first portion 131 (see Fig. 5A) or the second portion 132 (see Fig. 5E).

[0061] [Fifth Modification] A stator core according to a fifth modification will be described with reference to Fig. 5G. Fig. 5G is an enlarged cross-sectional view of a portion of the stator core according to the fifth modification. As shown in Fig. 5G, 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 both the first portion 131 and the second portion 132.

[0062] As can be seen from the first to fifth modified examples described above, the resin part 13 may include at least one selected from the group consisting of a first part 131, a second part 132, and a third part 133.

[0063] [Motor and Generator] An embodiment of the motor of the present disclosure will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a perspective view of the motor and generator in this embodiment. Fig. 7 is a cross-sectional view taken along line XX in Fig. 1.

[0064] 6 and 7 , the electric motor 2 includes a case 21, a shaft 22, a rotor 23, a stator core 1, and coils 24. The case 21 has a cylindrical shape having an axis B. The case 21 houses a portion of the shaft 22, the rotor 23, the stator core 1, and the coils 24. The shaft 22 shares the axis B with the case 21. The shaft 22 rotates about the axis B relative to the case 21. An end 221 of the shaft 22 in a direction parallel to the axis B is located outside the case 21.

[0065] The rotor 23 is fixed to a portion of the shaft 22. The rotor 23 has a common axis B with the shaft 22. The rotor 23 rotates about the axis B together with the shaft 22. The rotor 23 is composed of a permanent magnet. The stator core 1 is fixed to the inner surface of the case 21. The stator core 1 is located radially outside the rotor 23. The stator core 1 is located away from the outer circumferential surface of the rotor 23. The rotor 23 rotates relative to the stator core 1. The central axis A of the stator core 1 coincides with the axis B of the rotor 23. The coil 24 is located between the rotor 23 and the stator core 1. The coil 24 is located away from the outer circumferential surface of the rotor 23. The coil 24 is fixed to the inner surface 111 of the stator core 1.

[0066] The generator 3 has the same configuration as the electric motor 2. That is, the generator 3 includes a case 21, a shaft 22, a rotor 23, a stator core 1, and coils 24.

[0067] Stator cores 1 of samples A to C were manufactured according to the manufacturing method of one embodiment (see FIG. 1). Stator core 1 of sample D was manufactured by punching electromagnetic steel sheet 100 (see FIG. 8). Samples A to C are examples. Sample D is a comparative example. The manufacture of each of samples A to D will be described.

[0068] [Manufacturing Sample A] First, the stator core 1 was manufactured using the same procedure as in the above embodiment, including steps S10 to S50. The width w of the core wire portion 11 was 1.0 mm, the height h was 1.7 mm, the thickness t of the insulating film 12 was 1 to 3 μm, the outer diameter D of the stator core 1 was 19.6 mm, and the inner diameter was 17.6 mm. The annealing temperature in step S50 was 600°C.

[0069] Crystal orientation analysis using EBSD was performed on the obtained core wire portion 11 of Sample A. The EBSD conditions were as follows: Apparatus: Gemini 450 manufactured by ZEISS and Symmetry manufactured by Oxford Acceleration voltage: 15 kV, probe current: 22 nA, analysis area: ×200 (1 μm step) Sample pretreatment: Resin embedding and mechanical polishing followed by cross-section processing using argon ion polishing (CP) Note that the above are the EBSD conditions of this example, and the EBSD conditions are not limited to these.

[0070] As a result, the first ratio was 14.7% in each of the first portion P1, the second portion P2, and the third portion P3 of the core portion 11. The second ratio was 22.7% in each of the first portion P1, the second portion P2, and the third portion P3 of the core portion 11. The EBSD results are shown in Table 1.

[0071] [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 step S50 was changed from 600°C to 700°C. EBSD results showed that the first ratio in each of the first portion P1, the second portion P2, and the third portion P3 of the core portion 11 was 15.7%. The second ratio in each of the first portion P1, the second portion P2, and the third portion P3 of the core portion 11 was 23.6%. The EBSD results are shown in Table 1.

[0072] [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 step S50 was changed from 600°C to 710°C. EBSD results showed that the first ratio in each of the first portion P1, the second portion P2, and the third portion P3 of the core portion 11 was 12.1%. The second ratio in each of the first portion P1, the second portion P2, and the third portion P3 of the core portion 11 was 23.7%. The EBSD results are shown in Table 1.

[0073] [Manufacturing of Sample D] Fig. 8 is a plan view of the stator core of Sample D manufactured by punching electromagnetic steel sheets. As shown in Fig. 8, a plurality of electromagnetic steel sheets 100 were punched into annular shapes and then stacked to produce the core portion 11. Thereafter, the same steps S30 and S50 as those of Sample A were carried out in order. In this way, the stator core 1 was manufactured.

[0074] As a result of EBSD, the first ratio in the first portion P1 of the core portion 11 was 8.9%. The first ratio in the fourth portion P4 of the core portion 11 was 8.3%. The fourth portion P4 was spaced 90 degrees from the first portion P1 in the circumferential direction around the central axis A. The standard deviation between the first ratio in the first portion P1 and the first ratio in the fourth portion P4 was 0.3%.

[0075] The second ratio in the first portion P1 of the core portion 11 was 15.9%. The second ratio in the fourth portion P4 of the core portion 11 was 15.1%. The standard deviation between the second ratio in the first portion P1 and the second ratio in the fourth portion P4 was 0.4%. The EBSD results are shown in Table 1.

[0076]

[0077] It should be understood that the embodiments and examples disclosed herein are illustrative in all respects and are not limiting in any respect. The scope of the present invention is defined not by the above description but by the claims, and it is intended to include all modifications within the meaning and scope of the claims.

[0078] 1 stator core, 2 electric motor, 3 generator, 10 insulating coated iron wire, 11 core wire portion, 12 insulating film, 13 resin portion, 21 case, 22 shaft, 23 rotor, 24 coil, 111 inner surface, 130 hardened body, 131 first part, 132 second part, 133 third part, 221 end, A central axis, B axis, L length parallel to the central axis of the stator core, L1, L2 lengths at two points 180 degrees apart in the circumferential direction around the central axis, 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 core portion having a spiral shape with a constant distance from a central axis and made of a wire made of electromagnetic soft iron or silicon steel; an insulating film covering an outer circumferential surface of the core portion, In the core wire portion, a first ratio, which is a ratio of crystals in which the angle between the radial direction of the spiral and the iron [100] direction is 15 degrees or less, is 10% or more, The stator core further includes a resin portion covering the insulating film, In a cross section including the central axis, the resin portion a first portion covering the insulating film, the first portion being located on the opposite side of the core wire portion from the central axis; a second portion covering the insulating film located between the core portion and the central axis; and a third portion located between the insulating films covering the adjacent core portions in a direction parallel to the central axis; At least one selected from the group consisting of the resin portion is a hardened body that bonds the insulating films that cover the core wire portions that are adjacent to each other in a direction parallel to the central axis, A stator core having an aspect ratio, which is the ratio of the length of the stator core in a direction parallel to the central axis to the outer diameter of the stator core, of 3 or more.

2. a first portion of the outer circumferential surface; a second portion spaced 120 degrees from the first portion in a circumferential direction around the central axis; a third portion spaced 120 degrees from the first portion and the second portion in a circumferential direction around the central axis; The stator core according to claim 1 , wherein a standard deviation of the first ratio is 0.2% or less.

3. a core portion having a spiral shape with a constant distance from a central axis and made of a wire made of electromagnetic soft iron or silicon steel; an insulating film covering an outer circumferential surface of the core portion, In the core wire portion, a second ratio, which is the ratio of crystals in which the angle between the radial direction of the spiral and the iron [100] direction is 20 degrees or less, is 20% or more, The stator core further includes a resin portion covering the insulating film, In a cross section including the central axis, the resin portion a first portion covering the insulating film, the first portion being located on the opposite side of the core wire portion from the central axis; a second portion covering the insulating film located between the core portion and the central axis; and a third portion located between the insulating films covering the adjacent core portions in a direction parallel to the central axis; At least one selected from the group consisting of the resin portion is a hardened body that bonds the insulating films that cover the core wire portions that are adjacent to each other in a direction parallel to the central axis, A stator core having an aspect ratio, which is the ratio of the length of the stator core in a direction parallel to the central axis to the outer diameter of the stator core, of 3 or more.

4. a first portion of the outer circumferential surface; a second portion spaced 120 degrees from the first portion in a circumferential direction around the central axis; a third portion spaced 120 degrees from the first portion and the second portion in a circumferential direction around the central axis; The stator core according to claim 3 , wherein a standard deviation of the second ratio is 0.2% or less.

5. 4. The stator core according to claim 1, wherein, in a cross section including 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. 4. The stator core according to claim 1, wherein a cross section of said core wire portion perpendicular to the longitudinal direction thereof is rectangular.

7. 4. The stator core according to claim 1, wherein a cross section of said core portion perpendicular to a longitudinal direction thereof has a height of 0.6 mm or less in a direction parallel to said central axis.

8. The stator core according to claim 1 or 3, wherein the insulating film is made of an inorganic material.

9. The stator core of claim 8 , wherein the inorganic material is a phosphate.

10. 4. The stator core according to claim 1, wherein the insulating film has a thickness of 0.1 μm or more and 30 μm or less.

11. A stator core as described in claim 1 or claim 3, wherein the aspect ratio is 10 or more.

12. An electric motor comprising the stator core according to claim 1 or 3.

13. A generator comprising the stator core according to claim 1 or 3.