JP2018148036A - Wound core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolled iron core provided with a grain-oriented electrical steel sheet having low iron loss and magnetic domain control from minute strain. SOLUTION: The wound iron core includes a wound iron core body having a substantially rectangular shape in a side view, and the wound iron core body has an inner surface side curvature radius r of more than 1 mm and less than 3 mm in a side view of a bent portion. A reflux magnetic domain composed of inner and outer steel plates of a directional electromagnetic steel plate and having a 180 ° magnetic wall parallel to the longitudinal direction, having a longitudinal dimension of 150 μm or less and a plate thickness direction of 30 μm or more. However, it has regions continuously and linearly in the width direction at intervals of 0.5 mm or more and 8 mm or less in the longitudinal direction, and the region in which the perfusion magnetic domain exists covers 25% or more of the surface surface surface of the steel plate on the inner surface side or the outer surface side. A wound iron core characterized by occupying. [Selection diagram] Fig. 1

Description

  The present invention relates to a wound iron core.

  Iron cores are widely used as magnetic cores for transformers, reactors, noise filters, and the like. Reduction of the iron loss generated in the iron core is one of the important issues from the standpoint of high efficiency, and conventionally, studies on the reduction of iron loss have been made from various viewpoints.

  In Patent Document 1, by irradiating the surface of a unidirectional electrical steel sheet used for an iron core with a pulse laser and introducing an appropriate minute strain, a reflux magnetic domain generation region of the steel sheet, a strain depth distribution, and a magnetic field A technique for matching a characteristic relationship to an optimum condition is disclosed. It is described that the unidirectional electrical steel sheet thus obtained has excellent low iron loss and low magnetostriction characteristics.

JP-A-11-279645

As iron cores that are generally put into practical use, stacked iron cores and wound iron cores are known. A stacked iron core is manufactured by stacking flat steel plates. However, since a wound iron core is manufactured by bending a steel plate, distortion due to deformation occurs during processing. Since the distortion causes an increase in the iron loss of the wound core, the annealing for removing the distortion is indispensable in the conventional method for manufacturing a wound core.
However, the micro strain introduced into the magnetic steel sheet by laser irradiation or the like is removed by annealing together with the strain caused by deformation when bending.
Therefore, for the purpose of reducing the iron loss of the wound iron core, there is a problem that the low iron loss directional electrical steel sheet introduced with the minute strain as described in Patent Document 1 cannot be applied to the wound iron core. there were.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a low iron loss wound core including a grain-oriented electrical steel sheet whose magnetic domain is controlled by minute strain.

  A wound iron core according to the present invention is a wound iron core provided with a substantially rectangular wound core body in a side view, and the wound core body includes plane portions and corner portions that are alternately continuous in the longitudinal direction. The directional electrical steel sheets having an angle of 90 ° formed by two adjacent flat parts in the part include parts stacked in the thickness direction, and have a substantially rectangular laminated structure in a side view, and each corner part Has two or more bent portions having a curved shape in the side view of the grain-oriented electrical steel sheet, and the total bending angle of each bent portion existing in one corner portion is 90 °. An inner surface side radius of curvature r in a side view of the bent portion is more than 1 mm and less than 3 mm, and is composed of a steel plate surface on the inner surface side and the outer surface side of the directional electromagnetic steel plate, and has a 180 ° domain wall parallel to the longitudinal direction. Longitudinal direction on the surface The magnetic domain having a size of 150 μm or less and a thickness in the thickness direction of 30 μm or more has a region that exists continuously and linearly in the width direction at intervals of 0.5 mm to 8 mm in the longitudinal direction, The region where the reflux magnetic domain exists occupies 25% or more of the steel plate surface area on the inner surface side or outer surface side.

The wound iron core of the present invention preferably has a region where the reflux magnetic domain exists on the outer surface side of the grain-oriented electrical steel sheet.
In the wound core of the present invention, it is preferable that the length of the wound core is 1.5 m or more.

  ADVANTAGE OF THE INVENTION According to this invention, the low iron loss wound iron core provided with the grain-oriented electrical steel sheet by which the magnetic domain control was carried out from the micro distortion can be provided.

FIG. 1 is a perspective view schematically showing one embodiment of a wound iron core. FIG. 2 is a side view of the wound iron core shown in the embodiment of FIG. FIG. 3 is a side view schematically showing another embodiment of the wound core. 4 is an enlarged side view of the vicinity of a corner portion in the embodiment of FIG. FIG. 5 is an enlarged side view of the vicinity of a corner portion in the embodiment of FIG. FIG. 6 is a side view schematically showing an example of a single-layer grain-oriented electrical steel sheet constituting the wound iron core. FIG. 7 is a side view schematically showing another example of a single-layer grain-oriented electrical steel sheet constituting the wound iron core. FIG. 8 is a side view schematically showing an example of a bent portion of the grain-oriented electrical steel sheet. FIG. 9 is a schematic diagram for specifying a region where a specific reflux magnetic domain exists on the steel plate surface. FIG. 10 is a schematic diagram illustrating an example of a bending method in the method of manufacturing a wound core. FIG. 11 is a schematic diagram showing dimensions of the wound iron cores manufactured in Examples 1 to 192 and Comparative Examples 1 to 436. FIG. 12 is a diagram showing the relationship between the laser irradiation conditions, the bent portion curvature radius, and BF. FIG. 13 is a diagram illustrating a relationship between the bending portion radius of curvature and BF for each occupation ratio of the specific reflux magnetic domain region under the laser irradiation condition C-3. FIG. 14 is a diagram showing the relationship between the bending portion curvature radius and BF for each occupation ratio of the specific reflux magnetic domain region under the laser irradiation condition D-3. FIG. 15 is a diagram showing the relationship between the bending portion radius of curvature and BF for each occupation ratio of the specific reflux magnetic domain region under the laser irradiation condition C-4. FIG. 16 is a diagram illustrating the relationship between the bending portion curvature radius and BF for each occupation ratio of the specific reflux magnetic domain region under the laser irradiation condition D-4. FIG. 17 is a diagram illustrating a relationship between the bending portion radius of curvature and the BF for each interval of the reflux magnetic domains in the longitudinal direction under the laser irradiation condition C-3. FIG. 18 is a diagram showing the relationship between the bending portion radius of curvature and BF for each interval of the reflux magnetic domains in the longitudinal direction under the laser irradiation condition D-3. FIG. 19 is a diagram showing the relationship between the bending portion radius of curvature and the BF for each interval of the reflux magnetic domains in the longitudinal direction under the laser irradiation condition C-4. FIG. 20 is a diagram showing the relationship between the bending portion radius of curvature and BF for each interval of the reflux magnetic domains in the longitudinal direction under the laser irradiation condition D-4.

Hereinafter, the wound iron core according to the present invention will be described in detail in order.
As used in this specification, the shape and geometric conditions and the degree thereof are specified. For example, terms such as “parallel”, “vertical”, “same”, “right angle”, length and angle values, etc. Is not limited to the strict meaning and should be interpreted to include a range where a similar function can be expected.

  A wound iron core according to the present invention is a wound iron core provided with a substantially rectangular wound core body in a side view, and the wound core body includes plane portions and corner portions that are alternately continuous in the longitudinal direction. The directional electrical steel sheets having an angle of 90 ° formed by two adjacent flat parts in the part include parts stacked in the thickness direction, and have a substantially rectangular laminated structure in a side view, and each corner part Has two or more bent portions having a curved shape in the side view of the grain-oriented electrical steel sheet, and the total bending angle of each bent portion existing in one corner portion is 90 °. An inner surface side radius of curvature r in a side view of the bent portion is more than 1 mm and less than 3 mm, and is composed of a steel plate surface on the inner surface side and the outer surface side of the directional electromagnetic steel plate, and has a 180 ° domain wall parallel to the longitudinal direction. Longitudinal direction on the surface The magnetic domain having a size of 150 μm or less and a thickness in the thickness direction of 30 μm or more has a region that exists continuously and linearly in the width direction at intervals of 0.5 mm to 8 mm in the longitudinal direction, The region where the reflux magnetic domain exists occupies 25% or more of the steel plate surface area on the inner surface side or outer surface side.

As described above, it is known that the grain-oriented electrical steel sheet into which minute strain is introduced by laser irradiation or the like exhibits excellent low iron loss characteristics because the magnetic domain is controlled.
However, since such micro strains are removed by annealing together with the strain caused by deformation during bending, the grain-oriented electrical steel sheet exhibiting excellent low iron loss characteristics by introducing micro strains is annealed after bending. It could not be applied to a wound iron core manufactured on the premise of
The present inventors, when using a grain-oriented electrical steel sheet having a region where a specific reflux magnetic domain exists due to the introduced micro-strain, the radius of curvature on the inner surface side of the bent portion formed by bending is in a specific range. It was found that a wound iron core with a low iron loss can be obtained without removing the distortion generated during bending by limiting to the above.
The reason why a low iron loss wound iron core having a grain-oriented electrical steel sheet into which minute strain is introduced can be obtained by the present invention is not clear, but it has a region where a specific reflux magnetic domain exists on the surface of the grain-oriented electrical steel sheet. In addition, when the radius of curvature on the inner surface side of the bent portion is within a specific range, it is presumed that there is an effect of canceling distortion generated during bending.

1. First, the shape of the wound iron core of the present invention will be described. FIG. 1 is a perspective view schematically showing one embodiment of a wound iron core. FIG. 2 is a side view of the wound iron core shown in the embodiment of FIG. FIG. 3 is a side view schematically showing another embodiment of the wound core.
In the present invention, the side view refers to viewing in the width direction (Y-axis direction in FIG. 1) of the long grain-oriented electrical steel sheet constituting the wound iron core, and the side view is visually recognized from the side view. FIG. 2 is a diagram (a diagram in the Y-axis direction in FIG. 1) showing the shape of

  The wound iron core of the present invention includes a substantially rectangular wound core body in a side view. In the wound core body, directional electromagnetic steel sheets are stacked in the thickness direction, and have a substantially rectangular laminated structure in a side view. The wound core body may be used as a wound core as it is, or may be provided with a known fastening tool such as a binding band in order to fix the wound core as necessary.

  In the present invention, the core length of the wound core body is not particularly limited, but even if the core length changes in the core, the volume of the bent portion is constant, so the iron loss generated in the bent portion is constant, and the core length is The longer the volume ratio of the bent portion is, the smaller the influence on iron loss deterioration is. Therefore, the length is preferably 1.5 m or more, and more preferably 1.7 m or more. In the present invention, the core length of the wound core body refers to the circumference at the center point in the stacking direction of the wound core body as viewed from the side.

  Since the iron core of the present invention has reduced iron loss, it can be suitably used for any conventionally known applications such as a magnetic core such as a transformer, a reactor, and a noise filter.

As shown in FIGS. 1 and 2, in the wound core body 10, the plane portions 4 and the corner portions 3 are alternately continued in the longitudinal direction, and the angle formed between the two plane portions 4 adjacent to each other at each corner portion 3 is 90 °. The grain-oriented electrical steel sheet 1 that is ° includes a portion stacked in the thickness direction, and has a substantially rectangular laminated structure 2 in a side view.
Each corner portion 3 of the grain-oriented electrical steel sheet 1 has two or more bent portions 5 having a curved shape in a side view, and the bending angle of each bent portion existing in one corner portion is the same. The total is 90 °.
The embodiment shown in FIG. 2 is a case where two bent portions 5 are provided in one corner portion 3. The embodiment of FIG. 3 is a case where there are three bent portions 5 in one corner portion 3.

4 and 5 are enlarged side views of the vicinity of the corner portion in the embodiment of FIGS. 2 and 3, respectively. 4 and 5, the bent portion indicates a portion having a curved shape, and has portions having a linear shape on both sides of the portion having the curved shape.
As shown in the examples of FIGS. 4 and 5, in the present invention, since one corner portion is constituted by two or more bent portions, a linear portion representing the first plane portion of the grain-oriented electrical steel sheet. The first bent portion (curved portion) is continuous with the straight portion, the second bent portion, and another straight portion, and the bent portion and the straight portion are alternately continued to the corner. A shape in which a linear part representing the second plane part of the grain-oriented electrical steel sheet is continuous from the last bent part in the part and adjacent to the first plane part via the corner part. Have

  In the example of FIG. 4, a region from the line segment A-A ′ to the line segment B-B ′ is set as the corner portion 3. Point A is an end point on the flat portion 4a side in the bent portion 5a of the directional electromagnetic steel sheet 1a arranged on the innermost side of the wound iron core 10, and the point A ′ passes through the point A and is a plate surface of the directional electromagnetic steel sheet 1a. The intersection of the straight line perpendicular to the outermost surface of the wound core body 10. Similarly, the point B is an end point on the flat portion 4b side in the bent portion 5b of the directional electromagnetic steel sheet 1a disposed on the innermost side of the wound iron core 10, and the point B ′ passes through the point B and the directional electromagnetic steel sheet 1a. This is the intersection of a straight line perpendicular to the plate surface and the outermost surface of the wound core body 10. In FIG. 4, the angle formed by two plane portions 4a and 4b adjacent via the corner portion 3 is θ, and in the present invention, the angle is 90 °. The bending angle φ of the bent portion will be described later. In FIG. 4, φ1 + φ2 is 90 °.

  Next, an example having three or more bent portions 5 in the corner portion 3 will be described. FIG. 5 is an enlarged view of the vicinity of a corner portion in the embodiment of FIG. In FIG. 5 as well, the area from the line segment A-A ′ to the line segment B-B ′ is defined as the corner portion 3 as in FIG. In FIG. 5, point A is an end point on the flat portion 4a side of the bent portion 5a closest to the flat portion 4a, and point B is an end point on the flat portion 4b side of the bent portion 5b closest to the flat portion 4b. When there are three or more bent portions, a straight portion exists between the bent portions. Which straight line portion constitutes the plane portion 4 may be determined in consideration of the angle θ formed by two plane portions adjacent to each other via the corner portion being 90 °. The bend 5 adjacent to the is determined. In the example of FIG. 5, φ1 + φ2 + φ3 is 90 °, and in general, when there are n bent portions in the corner portion, φ1 + φ2 +... + Φn is 90 °.

In the present invention, since the angle θ of the corner portion described above is 90 °, φ is less than 90 °. From the viewpoint of suppressing the generation of distortion due to deformation during processing and suppressing iron loss, φ is preferably 60 ° or less, and more preferably 45 ° or less.
In the embodiment shown in FIG. 4 having two bent portions at one corner, for example, φ1 = 60 ° and φ2 = 30 °, or φ1 = 45 ° and φ2 = 45 ° from the viewpoint of reducing iron loss. Etc. Further, in the embodiment of FIG. 5 having three bent portions at one corner portion, for example, φ1 = 30 °, φ2 = 30 °, φ3 = 30 °, and the like from the viewpoint of reducing iron loss. Furthermore, from the standpoint of production efficiency, it is preferable that the bending angle is equal. Therefore, when there are two bent portions at one corner portion, it is preferable that φ1 = 45 ° and φ2 = 45 °. In the embodiment shown in FIG. 5 having three bent portions at one corner, it is preferable to set, for example, φ1 = 30 °, φ2 = 30 ° and φ3 = 30 ° from the viewpoint of reducing iron loss.

The bent portion 5 will be described in more detail with reference to FIG. FIG. 8 is a diagram schematically illustrating an example of a bent portion (curved portion) of the grain-oriented electrical steel sheet. The bending angle of the bent portion means a difference in angle generated between the straight portion on the rear side and the straight portion on the front side in the bending direction in the directional electromagnetic steel plate bent portion. The complementary angle of the angle formed by the two virtual lines Lb-longation 1 and Lb-longation 2 obtained by extending the straight line portions adjacent to both sides (point F and point G) of the curved line portion included in the line Lb representing the outer surface Expressed as φ.
The bending angle of each bending portion is less than 90 °, and the total bending angle of all the bending portions existing in one corner portion is 90 °.

  In the present invention, the bent portion refers to a point D and a point E on the line La representing the inner surface of the directional electromagnetic steel sheet and a point on the line Lb representing the outer surface of the directional electromagnetic steel sheet in a side view of the directional electromagnetic steel sheet. When F and point G are defined as follows, a line delimited by point D and point E on line La representing the inner surface of the grain-oriented electrical steel sheet, a point on line Lb representing the outer surface of the grain-oriented electrical steel sheet An area surrounded by a line divided by F and point G, a straight line connecting point D and point E, and a straight line connecting point F and point G is shown.

Here, the point D, the point E, the point F, and the point G are defined as follows.
Extending the straight line portions adjacent to the center point A of the radius of curvature in the curve portion included in the line La representing the inner surface of the grain-oriented electrical steel sheet and the both sides of the curve portion included in the line Lb representing the outer surface of the grain-oriented electrical steel sheet The point C where the straight line AB connecting the intersection point B of the two virtual lines Lb-elongation 1 and Lb-elongation 2 obtained by crossing the line representing the inner surface of the grain-oriented electrical steel sheet is defined as an origin C.
A point separated from the origin C by a distance m represented by the following formula (2) along one line La along the line La representing the inner surface of the grain-oriented electrical steel sheet,
A point separated from the origin C along the line La representing the inner surface of the grain-oriented electrical steel sheet by the distance m in another direction is a point E,
Of the straight line portions included in the line Lb representing the outer surface of the grain-oriented electrical steel sheet, the straight line portion facing the point D and the straight line portion facing the point D are drawn perpendicularly and pass through the point D. Let the point of intersection with the virtual line be point G,
Of the straight line portions included in the line Lb representing the outer surface of the grain-oriented electrical steel sheet, the straight line portion facing the point E and the straight line portion facing the point E are drawn perpendicularly and pass through the point E. Let the intersection with the virtual line be a point F.
Formula (1): m = r × (π / 4)
(In formula (1), m represents the distance from the point C, and r represents the distance (curvature radius) from the center point A to the point C).

That is, r indicates the radius of curvature when the curve near the point C is regarded as an arc, and in the present invention, represents the inner radius of curvature in a side view of the bent portion. The curvature of the curved portion of the bent portion is steeper as the radius of curvature r is smaller, and the curvature of the curved portion of the bent portion is more gradual as the radius of curvature r is larger.
In the wound iron core of the present invention, the radius of curvature at each bent portion of each grain-oriented electrical steel sheet laminated in the plate thickness direction may have a certain degree of error. When there is an error, the curvature radius of each bent portion is specified as an average value of the curvature radii of the stacked steel plates. Moreover, when there exists an error, it is preferable that the error is 0.1 mm or less.
In addition, although there is no restriction | limiting in particular in the measuring method of the curvature radius of a bending part, For example, it can measure by observing 200 times using a commercially available microscope (Nikon ECLIPSE LV150).
In the present invention, a wound core having a low iron loss is obtained by combining the curvature radius r of the bent portion with a specific grain-oriented electrical steel sheet whose magnetic domain is controlled by a micro-strain described below as a range exceeding 1 mm and less than 3 mm. It became possible to get.

6 and 7 are diagrams schematically showing an example of the grain-oriented electrical steel sheet for one layer in the wound core body. As shown in the examples of FIGS. 6 and 7, the grain-oriented electrical steel sheet used in the present invention is bent, and includes a corner portion 3 composed of two or more bent portions 5 and a plane portion. 4, a substantially rectangular ring is formed in a side view through the joint 6 on the end face in the width direction of one or more grain-oriented electrical steel sheets.
In the present invention, the wound core body only has to have a laminated structure having a substantially rectangular shape in a side view as a whole. As shown in the example of FIG. 6, one directional electrical steel sheet may constitute one layer of the wound core body through one joint portion 6, and is shown in the example of FIG. 7. Thus, one directional electromagnetic steel sheet constitutes about a half circumference of the wound iron core, and two directional electromagnetic steel sheets constitute one layer of the wound iron core body through two joints 6. There may be.
As another example, when two directional electrical steel sheets constitute one layer of a wound core body, a bent body corresponding to approximately three sides of a rectangular shape and a straight edge corresponding to the remaining one side ( A substantially rectangular ring may be formed by combining steel plates having a straight side view. Thus, when two or more grain-oriented electrical steel sheets constitute one layer of the wound core body, a bent steel sheet and a straight steel plate (in a side view in a straight line) may be combined. As yet another example, a directional electrical steel sheet having a length of two or more layers of the wound core body is bent to form a bent body in which a substantially rectangular ring continues two or more times, They may be stacked in the thickness direction.
In any case, in order to prevent a gap from being generated between two adjacent layers at the time of manufacturing the wound core, in the adjacent two-layer directional electromagnetic steel sheet, the outer peripheral length of the flat portion 4 of the directional electromagnetic steel sheet disposed inside The length of the steel plate and the position of the bent portion are adjusted so that the inner peripheral length of the flat portion 4 of the grain-oriented electrical steel plate disposed on the outside is equal.

  The plate thickness of the grain-oriented electrical steel sheet used in the present invention is not particularly limited, and may be appropriately selected depending on the application, etc., but is usually in the range of 0.15 mm to 0.35 mm, preferably The range is from 0.18 mm to 0.23 mm.

2. Next, the configuration of the grain-oriented electrical steel sheet that constitutes the wound core body will be described. In the grain-oriented electrical steel sheet used in the present invention, the longitudinal dimension is 150 μm or less and the dimension in the sheet thickness direction is a surface having a 180 ° domain wall parallel to the longitudinal direction, which is constituted by the steel sheet surfaces on the inner surface side and the outer surface side. The reflux magnetic domain of 30 μm or more has a region that exists continuously and linearly in the width direction at intervals of 0.5 mm or more and 8 mm or less in the longitudinal direction, and the region where the reflux magnetic domain exists is on the inner surface side or outer surface side Account for 25% or more of the surface area of the steel sheet.

(1) Region in which a specific reflux magnetic domain exists Generally, a grain-oriented electrical steel sheet is a crystal grain orientation in the steel sheet that is highly accumulated in the {110} <001> orientation and the easy magnetization axis is aligned in the longitudinal direction. Steel plate. Since the easy magnetization axis is aligned in the longitudinal direction, it refers to an electrical steel sheet having the characteristics of low iron loss and excellent magnetism.
On the other hand, it is known that in a grain-oriented electrical steel sheet, a striped magnetic domain structure called a main magnetic domain divided on the surface by 180 ° domain walls parallel to the longitudinal direction is observed. Here, the width of the main magnetic domain is determined so as to minimize the domain wall and the magnetostatic energy, and there is a proportional relationship that the iron loss of the electrical steel sheet is relatively larger as the width of the main magnetic domain is wider. Are known.
Therefore, for the purpose of further improving the iron loss of the grain-oriented electrical steel sheet having excellent magnetic properties, a technique for controlling the magnetic domain by introducing strain on the steel sheet surface is known. By the formed reflux magnetic domain, the width of the main magnetic domain is subdivided to improve the iron loss.

In the present invention, the longitudinal dimension is 150 μm or less and the dimension in the plate thickness direction is 30 μm or more on the surface having a 180 ° domain wall parallel to the longitudinal direction, which is constituted by the inner and outer steel plate surfaces. A grain-oriented electrical steel sheet in which a certain reflux magnetic domain exists is used.
In the present invention, a grain-oriented electrical steel sheet having a reflux magnetic domain having a longitudinal dimension of 150 μm or less and a thickness dimension of 30 μm or more (hereinafter sometimes referred to as “specific reflux domain”) is used. Thus, by setting the curvature radius r of the bent portion to be in the range of more than 1 mm and less than 3 mm, it is possible to obtain a wound core with a low iron loss without removing the distortion of the bent portion by annealing. Here, in the present invention, the return magnetic domain refers to an auxiliary magnetic domain of a type that returns the magnetization of the main magnetic domain.
There are no particular limitations on the method of measuring the longitudinal dimension of such a reflux magnetic domain, and examples include a method (magnetic domain SEM) of observing and measuring using reflected electrons of SEM.
Moreover, although there is no restriction | limiting in the measuring method of the dimension of a plate | board thickness direction, For example, it etches with the nitric acid of a steel plate surface layer, and it confirms by whether a magnetic domain of a surface layer is observed by magnetic domain SEM for every fixed depth. (Hereinafter sometimes referred to as an etching method).

Further, there is no particular limitation on the method for forming such a return magnetic domain, but it is preferable to form the return magnetic domain by introducing distortion by laser irradiation because the size of the return magnetic domain is easy to control. For example, when a pulse laser is used, the dimension in the longitudinal direction can be controlled by irradiating the laser beam so as to overlap, and the dimension in the depth direction can be controlled by adjusting the irradiation diameter.
Such distortion due to laser irradiation is introduced by rapid heating and rapid cooling of the steel sheet. The heating rate by laser irradiation is proportional to the energy density per unit time introduced into the steel sheet by the irradiated laser. The energy density can be controlled as energy density (mJ / mm ² ), which is irradiation energy per unit area, and the strain introduction efficiency becomes higher when the laser is irradiated at a higher energy density. The energy density may be, for example, 80 mJ / mm ² .
The dimension in the longitudinal direction and the dimension in the plate thickness direction of the return magnetic domain due to laser irradiation can be controlled, for example, by changing the spot diameter of the laser to be irradiated. The spot diameter can be controlled by adjusting the lengths in the longitudinal direction L and the width direction C in the range of 70 to 530 μm and 200 to 10,000 μm, respectively.
For this reason, in order to introduce the optimum reflux magnetic domain by laser irradiation, the spot diameter is not effective even if the length in the longitudinal direction L is too short, and if it is too long, the characteristics are adversely affected. If the width direction C is too short, there is no effect, and if it is too long, there is no adverse effect on the characteristics, but there is an optimum value from the viewpoint of cost because the total amount of energy input is too large.
The effect of obtaining a wound iron core with low iron loss without removing the distortion of the bent portion by annealing is not particularly limited as long as the dimension in the longitudinal direction of the reflux magnetic domain is 150 μm or less, but has a magnetic domain refinement effect. Therefore, the longitudinal dimension of the reflux magnetic domain is preferably 50 μm or more, and more preferably 70 μm or more and less than 100 μm.
Further, in the effect of obtaining a wound iron core having a low iron loss without removing the distortion of the bent portion by annealing, there is no particular limitation as long as the dimension in the thickness direction of the reflux magnetic domain is 30 μm or more, but it is more than 50 μm. For the reason that the effect is saturated even if the depth is increased, the dimension of the reflux magnetic domain in the thickness direction is preferably 50 μm or less, and more preferably 35 to 45 μm.

Moreover, in this invention, the area | region where the specific recirculation | reflux magnetic domain exists continuously and linearly in the width direction by the space | interval of 0.5 mm or more and 8 mm or less in a longitudinal direction on the surface comprised by the steel plate surface of an inner surface side and an outer surface side. (Hereinafter, referred to as a “specific reflux magnetic domain region”), and a grain-oriented electrical steel sheet that occupies 25% or more of the steel sheet surface area on the inner surface side or outer surface side is used.
In the present invention, the surface formed by the steel plate surfaces on the inner surface side and the outer surface side has a region in which specific reflux magnetic domains exist continuously and linearly in the width direction at intervals of 0.5 mm to 8 mm in the longitudinal direction. And using the grain-oriented electrical steel sheet in which the area occupies 25% or more of the steel plate surface area on the inner surface side or outer surface side, the curvature radius r of the bent portion is set to a range exceeding 1 mm and less than 3 mm. Thus, it is possible to obtain a wound iron core with low iron loss without removing the distortion of the bent portion by annealing.
In order to obtain a wound iron core having a low iron loss, it is preferable that the region where the specific reflux magnetic domain exists occupy 50% or more of the steel plate surface area on the inner surface side or outer surface side, and more preferably 75% or more.

  Here, the region in which the specific reflux magnetic domain exists refers to a region existing on the surface constituted by the steel plate surfaces on the inner surface side and the outer surface side, and is a concept that does not include a region existing on the surface in the plate thickness direction (hereinafter referred to as the following) The surface constituted by the steel plate surface on the inner surface side and the outer surface side is simply “steel plate surface”, the steel plate surface on the inner surface side, simply “the inner surface of the steel plate”, and the steel plate surface on the outer surface side is simply “ Sometimes referred to as “steel plate outer surface”).

As described above, since a wide main magnetic domain is formed in parallel to the longitudinal direction on the surface of the grain-oriented electrical steel sheet, a reflux magnetic domain is introduced by introducing a micro strain on a straight line parallel to the width direction of the electrical steel sheet. And the main magnetic domain is subdivided.
FIG. 9 shows a schematic diagram of a region where a specific reflux magnetic domain exists on the steel plate surface.
In order to efficiently subdivide the main magnetic domain by the return magnetic domain, the return magnetic domain is continuously formed on a straight line that is parallel to the width direction of the magnetic steel sheet and drawn with respect to the entire width. By repeating, the specific reflux magnetic domain area | region of the steel plate surface is formed.
Therefore, in the present invention, when the origin is taken on the surface of the steel plate as shown in FIG. 9, the longitudinal direction is the x axis and the width direction is the y axis, X1 which is the smallest x coordinate where the specific reflux magnetic domain exists is set. The straight line parallel to the y-axis passing through is defined as l, and the straight line parallel to the y-axis passing through the largest x coordinate X2 where the specific return magnetic domain exists is defined as lM, and then the region between the straight line l and the straight line lM is specified. It is defined as a region where a reflux magnetic domain exists.
The presence of the return magnetic domain means that a straight line in which a specific return magnetic domain is formed between the straight line 1 and the straight line 1M (in the x-axis direction) at intervals of 0.5 to 8 mm, and in the straight line (y-axis) The direction is not particularly limited as long as the specific reflux magnetic domain is continuously present.
When there are a plurality of specific reflux magnetic domain regions separately in a single steel plate at intervals exceeding 8 mm, the region area is defined by adding each region area. Also, the region where the distance between the straight line 1 and the straight line 1M (x-axis direction) is smaller than 0.5 mm is not included in the specific reflux magnetic domain region.

As long as the specific reflux magnetic domain region occupies 25% or more of the steel plate surface area on the inner surface side or the outer surface side, the distribution is not particularly limited, and there may be only one specific reflux magnetic domain region, as described above. A plurality of them may exist separately.
Since the effect of reducing the core loss of the wound core is high, it is preferable to have a part or all of the specific reflux magnetic domain region on the outer surface side of the steel plate.
It is known that the iron loss is reduced with the surface tension in the electromagnetic steel sheet introduced with minute strain, and in the electromagnetic steel sheet processed to form a ring, the outer surface side surface is more than the inner surface side surface. This is because a strong tension is generated.

(2) Base Steel As described above, in the grain-oriented electrical steel sheet used in the present invention, the base steel sheet is a steel sheet in which the orientation of crystal grains in the base steel sheet is highly integrated in the {110} <001> orientation. It has excellent magnetic properties in the rolling direction.
In the present invention, the mother steel plate is not particularly limited, and can be appropriately selected from those known as grain-oriented electrical steel plates. Hereinafter, although an example of a preferable mother steel plate will be described, in the present invention, the mother steel plate is not limited to the following.

The chemical composition of the mother steel plate is not particularly limited. For example, in mass%, Si: 0.8% to 7%, C: higher than 0% and 0.085% or less, acid-soluble Al: 0 % To 0.065%, N: 0% to 0.012%, Mn: 0% to 1%, Cr: 0% to 0.3%, Cu: 0% to 0.4%, P: 0% to 0.5%, Sn: 0% to 0.3%, Sb: 0% to 0.3%, Ni: 0% to 1%, S: 0% to 0.015%, Se: 0% to 0. It is preferable that 015% is contained and the balance consists of Fe and impurities. The chemical composition of the mother steel plate is a preferable chemical component for controlling the Goss texture in which the crystal orientation is accumulated in the {110} <001> orientation. Of the elements in the mother steel plate, Si and C are basic elements, and acid-soluble Al, N, Mn, Cr, Cu, P, Sn, Sb, Ni, S, and Se are selective elements. Since these selective elements may be contained according to the purpose, there is no need to limit the lower limit value, and it may not be contained substantially. Moreover, even if these selective elements are contained as inevitable impurities, the effects of the present invention are not impaired. In the mother steel plate, the balance of the basic element and the selective element is composed of Fe and inevitable impurities.
In the present invention, “inevitable impurities” means elements inevitably mixed from ore as a raw material, scrap, or a manufacturing environment when industrially producing a mother steel plate.
In general, grain oriented electrical steel sheets undergo purification annealing during secondary recrystallization. In the purification annealing, the inhibitor forming elements are discharged out of the system. In particular, for N and S, the decrease in the concentration is remarkable, and it becomes 50 ppm or less. Under normal purification annealing conditions, 9 ppm or less, further 6 ppm or less. If the purification annealing is sufficiently performed, it reaches a level that cannot be detected by general analysis (1 ppm or less).
The chemical composition of the mother steel plate may be measured by a general steel analysis method. For example, the chemical composition of the mother steel plate may be measured using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). Specifically, for example, a 35 mm square test piece is obtained from the center position of the mother steel plate after removal of the coating, and is based on a calibration curve prepared in advance by Shimadzu ICPS-8100 or the like (measurement device). It can be specified by measuring. C and S may be measured using a combustion-infrared absorption method, and N may be measured using an inert gas melting-thermal conductivity method.
In addition, the chemical component of the base steel plate is a component obtained by analyzing a component of a steel plate obtained by removing a glass coating and a coating containing phosphorus described below from a grain-oriented electrical steel plate by a method described below.

The manufacturing method of a base steel plate is not specifically limited, The manufacturing method of a conventionally well-known grain-oriented electrical steel plate can be selected suitably. As a preferable specific example of the production method, for example, after C is 0.04 to 0.1% by mass, and the others are hot-rolled by heating a slab having the chemical composition of the base steel plate to 1000 ° C. or higher. Then, if necessary, hot-rolled sheet annealing is performed, and then cold-rolled steel sheet is formed by cold rolling at least once with intermediate or intermediate annealing, and the cold-rolled steel sheet is 700 in a wet hydrogen-inert gas atmosphere, for example. Examples include a method of heating to ˜900 ° C., decarburizing annealing, further nitriding annealing as necessary, and finish annealing at about 1000 ° C.
In the present invention, the thickness of the base steel plate is not particularly limited, but is preferably 0.1 mm or more and 0.5 mm or less, and more preferably 0.15 mm or more and 0.40 mm or less.

(3) Coating In the present invention, the grain-oriented electrical steel sheet may have a coating on the surface as long as the effects of the present invention are not impaired. Examples of such a coating include a glass coating formed on a mother steel plate. The glass coating includes, for example, one or more oxides selected from forsterite (Mg ₂ SiO ₄ ), spinel (MgAl ₂ O ₄ ), and cordierite (Mg ₂ Al ₄ Si ₅ O ₁₆ ). A film is mentioned.

The method for forming the glass coating is not particularly limited, and can be appropriately selected from known methods. For example, in a specific example of the manufacturing method of the base steel sheet, after the cold separator steel sheet is coated with an annealing separator containing one or more selected from magnesia (MgO) and alumina (Al ₂ O ₃ ), the finishing is performed. A method of annealing is mentioned. In addition, the said annealing separator has the effect which suppresses the sticking of the steel plates at the time of finish annealing. For example, when finish annealing is performed by applying the annealing separator containing magnesia, a glass coating containing forsterite (Mg ₂ SiO ₄ ) is formed on the surface of the base steel plate by reacting with silica contained in the base steel plate. The
In the present invention, the thickness of the glass coating is not particularly limited, but is preferably 0.5 μm or more and 3 μm or less.

3. Method for manufacturing wound core The method for manufacturing a wound core according to the present invention is not particularly limited as long as the wound core according to the present invention can be manufactured. Usually, the steel sheet surfaces on the inner surface side and the outer surface side of the grain-oriented electrical steel sheet On the surface having a 180 ° domain wall parallel to the longitudinal direction, a reflux magnetic domain having a longitudinal dimension of 150 μm or less and a thickness direction dimension of 30 μm or more has a spacing of 0.5 mm or more and 8 mm or less in the longitudinal direction. And preparing a grain-oriented electrical steel sheet that has a region that exists continuously and linearly in the width direction, and in which the region in which the reflux magnetic domain exists occupies 25% or more of the steel sheet surface area on the inner surface side or outer surface side. And bending the at least two places for each corner portion formation region pre-assigned on the grain-oriented electrical steel sheet to form a bent portion having a radius of curvature r of more than 1 mm and less than 3 mm. A step of forming a magnetic conductive steel sheet into a bent body in which flat portions and corner portions are alternately continuous and an angle between two adjacent flat portions in each corner portion is 90 °; A step of forming the bending processed body by aligning the corner portions with each other, laminating and stacking the grain-oriented electrical steel sheets in the thickness direction, and forming a substantially rectangular laminate in a side view. It can manufacture efficiently by the manufacturing method which does not have an annealing process later.
Hereinafter, the manufacturing method of the said wound iron core is demonstrated in detail in order.

  First, the longitudinal dimension is 150 μm or less and the thickness dimension is 30 μm or more on the surface having 180 ° domain walls parallel to the longitudinal direction, which is composed of the steel sheet surfaces on the inner surface side and outer surface side of the grain-oriented electrical steel sheet. The reflux magnetic domain has a region that exists continuously and linearly in the width direction at intervals of 0.5 mm or more and 8 mm or less in the longitudinal direction, and the region occupies 25% or more of the steel plate surface area on the inner surface side or outer surface side. Prepare the grain-oriented electrical steel sheet. The grain-oriented electrical steel sheet may be manufactured or a commercially available product may be obtained. Since the manufacturing method and chemical composition of the grain-oriented electrical steel sheet are as described above, description thereof is omitted here.

Next, after cutting the grain-oriented electrical steel sheet to a desired length, bending is performed at least two places in each corner portion formation region pre-assigned on the grain-oriented electrical steel sheet so that the radius of curvature r is 1 mm. By forming a bent portion that is more than 3 mm and less than 3 mm, the plane portion and the corner portion are alternately continued from the grain-oriented electrical steel sheet, and the angle formed by two adjacent plane portions in each corner portion is A bending body that is 90 ° is formed.
A bending method will be described with reference to the drawings. FIG. 10 is a schematic diagram illustrating an example of a bending method in the method of manufacturing a wound core.
The configuration of the processing machine is not particularly limited. For example, as shown in FIG. 10A, the processing machine usually has a die 22 and a punch 24 for press working, and further has a grain-oriented electrical steel sheet 21. And a guide 23 for fixing. The grain-oriented electrical steel sheet 21 is transported in the transport direction 25 and fixed at a preset position (FIG. 10B). Next, by pressing with a predetermined force set in advance by the punch 24, a bent body having a bent portion with a bending angle φ is obtained.
Although there is no particular limitation on the method of setting the radius of curvature r of the bent portion to be in the range of more than 1 mm and less than 3 mm, usually, by changing the distance between the die 22 and the punch 24 and the shape of the die 22 and the punch 24, The curvature radius r of the bent portion can be adjusted to the specific range.
Processing is performed so that the radius of curvature r at the bent portion of each grain-oriented electrical steel sheet laminated in the plate thickness direction matches, but the radius of curvature of the processed steel sheet varies depending on the roughness and shape of the steel sheet surface layer. May occur. Even if an error occurs, the error is preferably 0.1 mm or less.
As described above, the method for measuring the radius of curvature of the bent portion is not particularly limited, but for example, it can be measured by observing at 200 times using a commercially available microscope (Nikon ECLIPSE LV150).

Usually, in the manufacturing process of a wound iron core, the process of removing the distortion of a bending part by the annealing after the said bending process is essential.
In the present invention, the longitudinal dimension is 150 μm or less and the dimension in the thickness direction is 30 μm on the surface having the 180 ° domain wall parallel to the longitudinal direction, which is constituted by the steel sheet surfaces on the inner surface side and outer surface side of the grain-oriented electrical steel sheet. The above-mentioned reflux magnetic domain has a region that exists continuously and linearly in the width direction at intervals of 0.5 mm or more and 8 mm or less in the longitudinal direction, and the region is 25% of the steel plate surface area on the inner surface side or outer surface side. By using the grain-oriented electrical steel sheet that occupies the above, by adjusting the curvature radius r of the bent portion to a range of more than 1 mm and less than 3 mm, it is possible to obtain the effect of canceling the distortion generated during bending, It is possible to obtain a wound iron core with low iron loss without going through a step of removing the distortion of the bent portion by annealing.

  Next, the directional electrical steel sheet, which is the bending processed body, is formed by aligning the corners and stacking them in the thickness direction to form a substantially rectangular laminate in a side view. Can be obtained. The obtained wound core body may be used as a wound core as it is, but may be further fixed by using a known fastening tool such as a binding band or the like as necessary.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

The technical contents of the present invention will be further described below with reference to examples of the present invention. The conditions in the examples shown below are condition examples adopted to confirm the feasibility and effects of the present invention, and the present invention is not limited to these condition examples. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.
In the description of the following examples, “the ratio of the specific reflux magnetic domain region occupied with respect to the steel plate surface area on the inner surface side or the outer surface side” may be referred to as “occupation ratio of the specific reflux magnetic domain region”.

1. Examination of relationship between dimension of reflux magnetic domain and radius of curvature of bent part (Example 1)
A grain-oriented electrical steel sheet having a glass coating containing forsterite (Mg ₂ SiO ₄ ) on a base steel sheet was prepared. 100% of the surface area of the steel sheet surface on the outer surface side after the bending process on the grain-oriented electrical steel sheet (hereinafter sometimes referred to as the occupation ratio of the irradiated region), that is, the outer surface side. The whole was irradiated with a pulse laser continuously and linearly in the width direction at intervals of 0.5 mm in the longitudinal direction. Note that the irradiation condition of the pulse laser was C-3 shown in Table 1.
The directional electrical steel sheet is bent while adjusting the radius of curvature of the bent part to be 1.25 mm, and has two bent parts with φ of 45 ° at one corner part. A grain-oriented electrical steel sheet that forms a ring was obtained. Next, by winding the grain-oriented electrical steel sheets, a wound core having the dimensions shown in FIG. 11 was obtained.

(Examples 2 to 20)
In Example 1, the wound cores of Examples 2 to 20 were obtained in the same manner as in Example 1 except that the irradiation conditions of the pulse laser and the curvature radius of the bent portion were changed as shown in Tables 1 and 3, respectively.

(Comparative Examples 1-150)
In Example 1, the wound cores of Comparative Examples 1 to 150 were obtained in the same manner as in Example 1 except that the irradiation conditions of the pulse laser and the curvature radius of the bent portion were changed as shown in Tables 1 and 3, respectively.

2. Examination of relationship between occupation ratio of specific reflux magnetic domain region and radius of curvature of bent portion (Examples 21 to 100)
In Example 1, the wound cores of Examples 21 to 100 were obtained in the same manner as in Example 1 except that the occupation ratio of the pulse laser irradiation region and the curvature radius of the bent portion were changed as shown in Table 1 and Table 4, respectively. It was.
(Comparative Examples 151-310)
In Example 1, the wound cores of Comparative Examples 151 to 310 were obtained in the same manner as in Example 1 except that the occupation ratio of the pulse laser irradiation region and the radius of curvature of the bent portion were changed as shown in Table 1 and Table 4, respectively. It was.

3. Examination of relationship between longitudinal distance of specific reflux magnetic domain and curvature radius of bent part (Examples 101 to 180)
In Example 1, except that the irradiation interval in the longitudinal direction of the pulse laser and the curvature radius of the bent portion were changed as shown in Table 1 and Table 5, respectively, the wound cores of Examples 101 to 180 were changed in the same manner as in Example 1. Obtained.
(Comparative Examples 311 to 430)
In Example 1, except that the irradiation interval in the longitudinal direction of the pulse laser and the radius of curvature of the bent part were changed as shown in Table 1 and Table 5, respectively, the wound cores of Comparative Examples 311 to 430 were changed in the same manner as in Example 1. Obtained.

4). Examination on the effect of having the specific reflux magnetic domain region on the inner surface side and on the outer surface side (Examples 181 to 192)
In Example 1, the directional electrical steel sheet has a radius of curvature of 1.5 mm at the bent portion, and the occupation ratio of the pulse laser irradiation region on the inner surface side or outer surface side of the directional electromagnetic steel sheet is as shown in Table 6 below. The cores of Examples 181 to 192 were obtained in the same manner as in Example 1 except that the inner surface side or the outer surface side of was irradiated with a pulse laser at intervals of 0.5 mm.
(Comparative Examples 431 to 436)
Example 181 is the same as Example 1 except that the pulse laser irradiation conditions and the occupation ratio of the pulse laser irradiation region on the inner surface side or outer surface side of the grain-oriented electrical steel sheet are changed as shown in Table 6 below. Thus, wound cores of Comparative Examples 431 to 436 were obtained.

4). Examination about influence of iron core length (Examples 193 to 207)
In Example 1, the radius of curvature of the bent portion is 1.5 mm, and the pulse laser is spaced at intervals of 0.5 mm so that the outer surface side surface of the directional electromagnetic steel sheet is 25% of the surface area of the steel sheet surface. Irradiation was performed, and the wound cores of Examples 193 to 207 were obtained in the same manner as in Example 1 except that the iron core length was changed as shown in Table 7 below.

5. Evaluation Method (1) Dimension Measurement of Reflux Magnetic Domain For the laser irradiation regions prepared in the above examples and comparative examples, magnetic domain observation is performed by a scanning electron microscope (SEM), and the longitudinal dimension and the plate thickness direction are measured. The dimensions of were measured. The dimension in the plate thickness direction was measured by the etching method described above.
The measurement results are shown in Table 1. In the case of irradiation conditions C-3, D-3, C-4, and D-4, a reflux magnetic domain having a longitudinal dimension of 150 μm or less and a thickness direction of 30 μm or more was confirmed on the steel sheet surface. In addition, in irradiation conditions C-3, D-3, C-4, and D-4, the laser irradiation area | region and the specific reflux magnetic domain area | region corresponded.

(2) Building factor Measurements using the excitation current method described in JIS C 2550-1 were performed on the wound cores of the examples and comparative examples under the conditions of a frequency of 50 Hz and a magnetic flux density of 1.7 T. It was determined the iron loss value _{W a.}
Used to manufacture the wound cores of the examples and comparative examples so as to reflect the laser irradiation conditions, the irradiation interval, and the occupancy rate of the irradiation area of the directional electrical steel sheets constituting the wound cores of the examples and comparative examples. The grain-oriented electrical steel sheet was taken out from each hoop around which the raw steel sheet was wound, and a sample having a width of 100 mm and a length of 500 mm was sheared. The sample was measured by a magnetic sheet single-sheet magnetic property test using the H coil method described in JIS C 2556 under the conditions of a frequency of 50 Hz and a magnetic flux density of 1.7 T. It was determined iron loss value W _B of the steel sheet veneers used in the manufacture.
Further, reference, the following Table 2, the steel sheet was irradiated with laser light under the conditions shown in Table 1 in the case of a 0.5mm in the longitudinal direction of the spacing, the relationship between the occupancy of the laser irradiation region and the iron loss value W _B Indicates. The reflux magnetic domains having a dimension in the longitudinal direction of 150 μm or less and a dimension in the thickness direction of 30 μm or more are the steel sheets of the irradiation conditions C-3, D-3, C-4 and D-4 in which the surface of the steel sheet is confirmed. in comparison with the steel sheet, it has been confirmed that low iron loss value W _B.
The building factor (BF) was determined by dividing the iron loss value W _{A of the} wound core by the iron loss value W _B of the electromagnetic steel sheet single plate. In the present invention, it can be evaluated that the smaller the BF, the less the influence of bending on the material steel plate. Moreover, if the BF of the wound iron core manufactured using the steel sheets having low iron loss under the irradiation conditions C-3, D-3, C-4 and D-4 is low, the iron loss compared with the conventional wound iron core. Can be evaluated as a reduced wound iron core.

6). Evaluation Results Tables 3-1 to 3-17 show the results of studies on the relationship between the size of the return magnetic domain (laser irradiation conditions) and the curvature radius of the bent portion. FIG. 12 illustrates the effects of the laser irradiation conditions and the radius of curvature on BF in Tables 3-1 to 3-17.
As shown in FIG. 12, the reflux magnetic domain having a longitudinal dimension of 150 μm or less and a thickness direction of 30 μm or more was not confirmed on the steel sheet surface, no laser irradiation, and A-1 to A-4, In the wound cores of Comparative Examples 1-110 and 121-140 using steel sheets irradiated with laser under the conditions of B-1 to B-4, C-1, C-2, D-1 and D-2, the radius of curvature r Regardless of the size, the iron loss deteriorated due to the bending of the steel plate with a BF of 1.11 or more.
Further, laser irradiation was performed under conditions of C-3, C-4, D-3 and D-4 in which a reflux magnetic domain having a longitudinal dimension of 150 μm or less and a thickness direction dimension of 30 μm or more was confirmed on the steel sheet surface. Even in the wound cores of Comparative Examples 111, 112, 113 to 120, 141, 142, and 143 to 150 manufactured by using a steel plate and setting the radius of curvature r to 1 mm or less, or 3 mm or more, BF is 1.13. As described above, the iron loss deteriorated by bending the material steel plate.

  On the other hand, a laser beam is produced according to the conditions of C-3, C-4, D-3 and D-4 in which a reflux magnetic domain having a longitudinal dimension of 150 μm or less and a thickness dimension of 30 μm or more is confirmed on the steel sheet surface. In Examples 1 to 20 wound cores manufactured by using the irradiated steel sheet and setting the radius of curvature r to 1.25 mm or more and 2.9 mm or less, BF was 1.01 or less, and the steel sheet was bent. However, it was revealed that the iron loss hardly deteriorated.

Next, the examination result regarding the influence of the occupation rate (%) of the specific reflux magnetic domain region is shown in Tables 4-1 to 4-4. 13 to 16 illustrate the influence of the occupation ratio (%) of the specific reflux magnetic domain region in Tables 4-1 to 4-4.
As shown in FIG. 13, the radius of curvature r is set to 1 using a steel sheet irradiated with laser under the condition of C-3 in which a reflux magnetic domain having a longitudinal dimension of 150 μm and a thickness dimension of 30 μm is confirmed on the steel sheet surface. In the wound iron core manufactured by setting it to 0.25 mm or more and 2.9 mm or less, even if the occupation ratio of the specific reflux magnetic domain region on the outer surface of the steel sheet is 10 to 20%, the iron loss is deteriorated by bending the material steel sheet. Although BF was suppressed to some extent, BF was 1.02 or more, and the deterioration of iron loss due to bending could not be completely suppressed.
On the other hand, in a wound core manufactured by using a steel plate in which the occupation ratio of the specific reflux magnetic domain region on the outer surface of the steel plate is 25% or more and setting the curvature radius r to 1.25 mm or more and 2.9 mm or less, Is 1.02 or less, and it has been clarified that the deterioration of iron loss due to bending can be almost completely suppressed.
Further, as shown in FIGS. 14 to 16, the steel plate irradiated with the laser according to the condition of D-3 in which the reflux magnetic domain having a dimension in the longitudinal direction of 50 μm and the dimension in the thickness direction of 30 μm was confirmed on the steel sheet surface, Steel plate irradiated with laser under the condition of C-4 in which a reflux magnetic domain having a dimension of 150 μm and a thickness direction dimension of 50 μm was confirmed on the steel sheet surface, a longitudinal dimension of 50 μm and a reflux dimension of 50 μm in the thickness direction Similarly, in the wound iron core manufactured using the steel sheet irradiated with the laser under the condition of D-4 in which the magnetic domain is confirmed on the steel sheet surface, when the occupation ratio of the specific reflux magnetic domain region on the outer surface side of the steel sheet is less than 25% Even if the radius of curvature r is set to 1.25 mm or more and 2.9 mm or less, the influence of bending cannot be completely removed, but the occupation ratio of the specific reflux magnetic domain region on the outer surface of the steel sheet is 25% or more. In some cases, it can be almost completely suppress deterioration of iron loss due to bending was revealed.

Next, Tables 5-1 to 5-4 show the examination results regarding the influence of the spacing in the longitudinal direction of the specific reflux magnetic domains that exist continuously and linearly in the width direction. 17 to 20 illustrate the influence of the distance in the longitudinal direction of specific reflux magnetic domains existing continuously and linearly in the width direction in Tables 5-1 to 5-4.
As shown in FIG. 13, the distance in the longitudinal direction of the reflux magnetic domain irradiated with laser under the condition of C-3 and having a longitudinal dimension of 150 μm and a thickness dimension of 30 μm, which exists continuously and linearly in the width direction. In the wound cores of Comparative Examples 331 to 340 manufactured using a steel sheet having a thickness of 9 mm, even when the curvature radius r is set to 1.25 mm or more and 2.9 mm or less, BF is 1.15 or more, and by bending The deterioration of the resulting iron loss could hardly be suppressed.
On the other hand, using a steel plate in which the longitudinal interval between the longitudinal magnetic domains having a longitudinal dimension of 150 μm and a thickness dimension of 30 μm, which exists continuously and linearly in the width direction, is 0.5 to 8 mm. In the manufactured wound core, when the radius of curvature r is set to 1.25 mm or more and 2.9 mm or less (Examples 101 to 120), BF is 1.02 or less, and the deterioration of iron loss caused by bending is reduced. It became clear that it could be almost suppressed.
Further, as shown in FIGS. 18 to 20, the steel plate irradiated with laser according to the condition of D-3 in which the reflux magnetic domain having a dimension in the longitudinal direction of 50 μm and the dimension in the thickness direction of 30 μm was confirmed on the steel sheet surface, Steel plate irradiated with laser under the condition of C-4 in which a reflux magnetic domain having a dimension of 150 μm and a thickness direction dimension of 50 μm was confirmed on the steel sheet surface, a longitudinal dimension of 50 μm and a reflux dimension of 50 μm in the thickness direction Similarly, a wound core manufactured using a steel sheet irradiated with a laser according to the condition of D-4 in which the magnetic domain was confirmed on the steel sheet surface was manufactured using a steel sheet in which the interval between the specific reflux magnetic domains in the longitudinal direction was 9 mm. In the iron core, even if the radius of curvature r is set to 1.25 mm or more and 2.9 mm or less, deterioration of iron loss caused by bending can hardly be suppressed. In a wound iron core manufactured using a steel sheet with a gap of 0.5 to 8 mm, when the curvature radius r is set to 1.25 mm or more and 2.9 mm or less, deterioration of iron loss caused by bending can be substantially suppressed. Became clear.

  Next, Table 6 shows the examination results regarding the effects when the specific reflux magnetic domain region is arranged on the inner surface side and the outer surface side.

  As shown in Table 6, even when a reflux magnetic domain having a longitudinal dimension of 150 μm and a thickness direction of 30 μm exists on the steel sheet surface, the specific reflux domain region on the outer surface side or inner surface side surface of the steel sheet In the wound cores of Comparative Examples 431 to 436 in which the occupancy ratio was less than 25%, BF was 1.03 or more, and a wound core with low iron loss could not be obtained.

  On the other hand, in the wound cores of Examples 181 to 192 in which the occupation ratio of the specific reflux magnetic domain region on the outer surface side or inner surface side of the steel plate is 25% or more, BF is 1.03 or less, and iron generated by bending It became clear that the deterioration of loss could be suppressed almost.

Here, when comparing the wound cores of Examples 181 to 188 under the same occupancy ratio of the specific reflux magnetic domain region, the BF of the wound cores of Examples 185 to 188 in which the specific reflux magnetic domain region is arranged on the inner surface side is 1. The BF of the wound iron cores of Examples 181 to 184 in which the specific reflux magnetic domain region was arranged on the outer surface side was 0.98 to 1.01 while it was 01 to 1.03.
Therefore, it has been clarified that in the electrical steel sheets having the same occupation ratio of the specific reflux magnetic domain region, the effect of suppressing the deterioration of iron loss caused by bending is higher when the specific reflux magnetic domain region is arranged on the outer surface side.
In the wound iron cores of Examples 181 to 184 in which the specific reflux magnetic domain region is arranged on the outer surface side and the wound iron cores in Examples 189 to 192 in which the specific reflux magnetic domain region is arranged on both sides, the specific reflux magnetic domain region on the outer surface side If the specific reflux magnetic domain region is arranged on the outer surface side and the specific reflux magnetic domain region is further arranged on the inner surface side, the BF is almost the same. It has become clear that there is no significant effect on

  Table 7 shows the results of the study on the effect of iron core length.

  As shown in Table 7, the winding cores of Examples 203 to 207 having an iron core length of 1.5 m or more have BF of 0.92 or less and the windings of Examples 193 to 202 having an iron core length of less than 1.5 m. It became clear that BF was low compared with the iron core.

  From the above results, it is a wound core provided with a substantially rectangular wound core body in a side view, and the wound core body has a planar portion and a corner portion that are alternately continuous in the longitudinal direction, and is adjacent to each corner portion. The directional electrical steel sheets having an angle of 90 ° formed by the two flat portions include portions stacked in the plate thickness direction and have a substantially rectangular laminated structure in a side view, and each corner portion has a direction. In the side view of the heat-resistant electrical steel sheet, it has two or more bent portions having a curved shape, and the total bending angle of each bent portion existing in one corner portion is 90 °, and the bending An inner surface side radius of curvature r in a side view of the portion is more than 1 mm and less than 3 mm, and is composed of a steel plate surface on the inner surface side and the outer surface side of the directional electromagnetic steel plate, and has a 180 ° domain wall parallel to the longitudinal direction. , Longitudinal dimension Has a region that is continuously and linearly present in the width direction at intervals of 0.5 mm or more and 8 mm or less in the longitudinal direction, the reflux magnetic domain having a thickness of 150 μm or less and a thickness direction dimension of 30 μm or more. It has been clarified that the wound core of the present invention has a low iron loss characteristic, in which the existing region occupies 25% or more of the surface area of the steel sheet on the inner surface side or outer surface side.

DESCRIPTION OF SYMBOLS 1, 1a Directional electrical steel sheet 2 Laminated body 3 Corner part 4, 4a, 4b Plane part 5, 5a, 5b, 5c Bending part 6 Joining part 10 Winding core body (winding core)
21 Directional electrical steel sheet 22 Die 23 Guide 24 Punch 25 Transport direction 26 Pressure direction

Claims (3)

A wound core comprising a substantially rectangular wound core body in a side view,
In the core body, the directional electrical steel sheet in which the plane portions and the corner portions are alternately continuous in the longitudinal direction, and the angle formed by the two plane portions adjacent to each other in the respective corner portions is 90 ° in the plate thickness direction. Including stacked portions, having a substantially rectangular laminated structure in side view,
Each corner portion has two or more bent portions having a curved shape in a side view of the grain-oriented electrical steel sheet, and the total bending angle of each bent portion existing in one corner portion is 90 °,
An inner surface side radius of curvature r in a side view of the bent portion is more than 1 mm and less than 3 mm;
Reflux having a longitudinal dimension of 150 μm or less and a thickness dimension of 30 μm or more on a surface having a 180 ° domain wall parallel to the longitudinal direction, which is constituted by the steel sheet surfaces on the inner and outer surfaces of the grain-oriented electrical steel sheet. The magnetic domain has a region that exists continuously and linearly in the width direction at intervals of 0.5 mm or more and 8 mm or less in the longitudinal direction,
The wound iron core is characterized in that the region where the reflux magnetic domain exists occupies 25% or more of the steel plate surface area on the inner surface side or the outer surface side.   2. The wound iron core according to claim 1, wherein a region where the return magnetic domain exists is provided on a steel plate surface on an outer surface side of the grain-oriented electrical steel plate.   The wound core according to claim 1 or 2, wherein the wound core has a core length of 1.5 m or longer.