JP6776952B2 - Winding iron core - Google Patents

Description

The present invention relates to a wound iron core.

The iron core is widely used as a magnetic core for transformers, reactors, noise filters, and the like. Reducing the iron loss generated in the iron core is one of the important issues from the viewpoint of improving efficiency, and the reduction of the iron loss has been studied from various viewpoints.

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

JP-A-11-279645

Stacked iron cores and wound iron cores are known as iron cores that are generally put into practical use. Stacked iron cores are manufactured by stacking flat steel plates, but wound steel cores are manufactured by bending steel plates, so distortion due to deformation occurs during processing. Since the strain causes a large iron loss in the wound core, annealing to remove this strain is indispensable in the conventional method for manufacturing the wound core.
However, the minute strain introduced into the electrical steel sheet by laser irradiation or the like is removed by annealing together with the strain generated by deformation during 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 electromagnetic steel sheet into which the minute strain is introduced 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 provided with a grain-oriented electrical steel sheet whose magnetic domain is controlled by minute strain.

The wound core according to the present invention is a wound core including a wound core body having a substantially rectangular shape in a side view, and the wound core body has flat surfaces and corners alternately continuous in the longitudinal direction, and the corners thereof. The directional electromagnetic steel plates having an angle of 90 ° formed by two adjacent flat surfaces in the portions include portions stacked in the plate thickness direction, and have a substantially rectangular laminated structure in a side view, and the respective corner portions. Has two or more bent portions having a curved shape in the side view of the directional electromagnetic steel plate, and the total bending angle of each of the bent portions existing in one corner portion is 90 °. The radius of curvature r on the inner surface side in the side view of the bent portion exceeds 1 mm and is less than 3 mm, and is composed of the steel plate surfaces on the inner surface side and the outer surface side of the directional electromagnetic steel plate, and has a 180 ° magnetic wall parallel to the longitudinal direction. On the surface of the surface, reflux magnetic sections having a longitudinal dimension of 150 μm or less and a plate thickness direction of 30 μm or more are 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. It is characterized in that the region having a region and the region where the reflux magnetic region exists occupies 25% or more of the surface surface surface surface of the steel plate on the inner surface side or the 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.
The wound iron core of the present invention preferably has an iron core length of 1.5 m or more.

According to the present invention, it is possible to provide a low iron loss wound core provided with a grain-oriented electrical steel sheet whose magnetic domain is controlled by minute strain.

FIG. 1 is a perspective view schematically showing an 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 iron core. FIG. 4 is an enlarged side view of the vicinity of the corner portion in the embodiment of FIG. FIG. 5 is an enlarged side view of the vicinity of the corner portion in the embodiment of FIG. FIG. 6 is a side view schematically showing an example of a one-layer grain-oriented electrical steel sheet constituting a wound steel core. FIG. 7 is a side view schematically showing another example of the one-layer grain-oriented electrical steel sheet constituting the wound steel core. FIG. 8 is a side view schematically showing an example of a bent portion of a grain-oriented electrical steel sheet. FIG. 9 is a schematic view for specifying a region where a specific reflux magnetic domain exists on the surface of the steel sheet. FIG. 10 is a schematic view showing an example of a bending processing method in a method for manufacturing a wound iron core. FIG. 11 is a schematic view showing the 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 condition and the radius of curvature of the bent portion and the BF. FIG. 13 is a diagram showing the relationship between the radius of curvature of the bent portion and the BF for each occupancy rate of the specific reflux magnetic domain region under the laser irradiation condition C-3. FIG. 14 is a diagram showing the relationship between the radius of curvature of the bent portion and the BF for each occupancy rate of the specific reflux magnetic domain region under the laser irradiation condition D-3. FIG. 15 is a diagram showing the relationship between the radius of curvature of the bent portion and the BF for each occupancy rate of the specific reflux magnetic domain region under the laser irradiation condition C-4. FIG. 16 is a diagram showing the relationship between the radius of curvature of the bent portion and the BF for each occupancy rate of the specific reflux magnetic domain region under the laser irradiation condition D-4. FIG. 17 is a diagram showing the relationship between the radius of curvature of the bent portion 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 radius of curvature of the bent portion and the 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 radius of curvature of the bent portion 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 radius of curvature of the bent portion and the 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.
It should be noted that, as used in the present specification, terms such as "parallel", "vertical", "same", "right angle", and values of length and angle, etc., which specify the shape and geometric conditions and their degrees, are used. Is not bound by the strict meaning, but is interpreted to include the range in which similar functions can be expected.

The wound core according to the present invention is a wound core including a wound core body having a substantially rectangular shape in a side view, and the wound core body has flat surfaces and corners alternately continuous in the longitudinal direction, and the corners thereof. The directional electromagnetic steel plates having an angle of 90 ° formed by two adjacent flat surfaces in the portions include portions stacked in the plate thickness direction, and have a substantially rectangular laminated structure in a side view, and each of the corner portions. Has two or more bent portions having a curved shape in the side view of the directional electromagnetic steel plate, and the total bending angle of each of the bent portions existing in one corner portion is 90 °. The radius of curvature r on the inner surface side in the side view of the bent portion exceeds 1 mm and is less than 3 mm, and is composed of the steel plate surfaces on the inner surface side and the outer surface side of the directional electromagnetic steel plate, and has a 180 ° magnetic wall parallel to the longitudinal direction. On the surface of the surface, reflux magnetic sections having a longitudinal dimension of 150 μm or less and a plate thickness direction of 30 μm or more are 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. It is characterized in that the region has a region and the region where the reflux magnetic region exists occupies 25% or more of the surface surface surface surface of the steel plate on the inner surface side or the outer surface side.

As described above, it is known that a grain-oriented electrical steel sheet into which fine strain is introduced by laser irradiation or the like exhibits excellent low iron loss characteristics because the magnetic domain is controlled.
However, since such fine strains are removed by annealing together with the strains generated by deformation during bending, the grain-oriented electrical steel sheets that are introduced with fine strains and exhibit excellent low iron loss characteristics are annealed after bending. It could not be applied to the winding iron core manufactured on the premise of.
The present inventors set the radius of curvature on the inner surface side of the bent portion formed by bending in a specific range when a grain-oriented electrical steel sheet having a region in which a specific free-flowing magnetic domain exists due to the introduced minute strain is used. It was found that a wound core with low iron loss can be obtained without removing the strain generated during bending.
Although it is not clear why the present invention can obtain a low iron loss wound core having a grain-oriented electrical steel sheet with introduced minute strain, there is a region where a specific recirculation magnetic domain exists on the surface of the grain-oriented electrical steel sheet. However, it is presumed that this is because when the radius of curvature on the inner surface side of the bent portion is within a specific range, it has the effect of canceling the strain generated during the bending process.

1. 1. Shape of Winding Core and Electrical Steel Sheet First, the shape of the wound core of the present invention will be described. FIG. 1 is a perspective view schematically showing an embodiment of a wound iron core. FIG. 2 is a side view of the wound iron core shown in the embodiment of FIG. Further, FIG. 3 is a side view schematically showing another embodiment of the wound iron core.
In the present invention, the side view means viewing in the width direction (Y-axis direction in FIG. 1) of the elongated grain-oriented electrical steel sheet constituting the wound steel core, and the side view is visually recognized by the side view. It is a figure (the figure in the Y-axis direction of FIG. 1) which showed the shape | shape.

The wound core of the present invention includes a wound core body having a substantially rectangular shape in a side view. The rolled iron core body has a laminated structure in which grain-oriented electrical steel sheets are stacked in the plate thickness direction and has a substantially rectangular shape in a side view. The wound core body may be used as it is as a wound core, or may be provided with a known fastener such as a binding band in order to fix the wound core as needed.

In the present invention, the iron core length of the wound iron core body is not particularly limited, but even if the iron core length changes in the iron core, the iron loss generated at the bent portion is constant because the volume of the bent portion is constant, and the iron core length is constant. The longer the volume fraction is, the smaller the volume fraction of the bent portion is, and therefore the influence on the deterioration of iron loss is small. In the present invention, the iron core length of the wound iron core body means the peripheral length at the center point in the stacking direction of the wound iron core body in a side view.

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

As shown in FIGS. 1 and 2, in the wound steel core main body 10, the flat surface portion 4 and the corner portion 3 are alternately continuous in the longitudinal direction, and the angle formed by the two adjacent flat surface portions 4 at each corner portion 3 is 90. The grain-oriented electrical steel sheet 1 having a temperature of ° includes a portion stacked in the plate 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 of the bent portions existing in one corner portion. The total is 90 °.
The embodiment of 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 three bent portions 5 are provided in one corner portion 3.

4 and 5 are enlarged side views of the vicinity of the corner portion in the embodiments of FIGS. 2 and 3, respectively. In FIGS. 4 and 5, the bent portion shows a portion having a curved shape, and the bent portion has a portion 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 composed of two or more bent portions, a linear portion representing the first flat portion of the directional electromagnetic steel plate. The first bent portion (curved portion) is continuous, and the bent portion and the straight portion are alternately continuous, such as a straight portion, a second bent portion, and another straight portion, and the corner is concerned. A shape in which a linear portion representing a second flat portion of a directional electromagnetic steel plate, which reaches the last bent portion in the portion and is adjacent to the first flat portion via a corner portion, is continuously formed. Has.

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

Next, an example in which three or more bent portions 5 are provided in the corner portion 3 will be described. FIG. 5 is an enlarged view of the vicinity of the corner portion in the embodiment of FIG. In FIG. 5, as in FIG. 4, the region from the line segment AA'to the line segment B-B'is defined as the corner portion 3. In FIG. 5, the point A is the end point on the flat surface portion 4a side of the bent portion 5a closest to the flat surface portion 4a, and the point B is the end point on the flat surface portion 4b side of the bent portion 5b closest to the flat surface portion 4b. When there are three or more bent portions, there is a straight portion between the bent portions. Which straight line portion constitutes the flat surface portion 4 may be determined in consideration of the angle θ formed by the two adjacent flat surface portions via the corner portions being 90 °, whereby the flat surface portion 4 may be determined. The bent portion 5 adjacent to the is determined. In the example of FIG. 5, φ1 + φ2 + φ3 is 90 °, and generally, when n bent portions are provided in the corner portion, φ1 + φ2 + ... + φn is 90 °.

In the present invention, φ is less than 90 ° because the angle θ of the corner portion described above is 90 °. From the viewpoint of suppressing the occurrence of strain due to deformation during processing and suppressing iron loss, φ is preferably 60 ° or less, and more preferably 45 ° or less.
In the embodiment of FIG. 4 having two bent portions in one corner portion, for example, φ1 = 60 ° and φ2 = 30 ° or φ1 = 45 ° and φ2 = 45 ° from the viewpoint of reducing iron loss. And so on. Further, in the embodiment of FIG. 5 having three bent portions at one corner portion, for example, φ1 = 30 °, φ2 = 30 °, φ3 = 30 °, etc. can be set from the viewpoint of reducing iron loss. Further, from the viewpoint of production efficiency, it is preferable that the bending angles are the same. Therefore, when one corner has two bent portions, it is preferable that φ1 = 45 ° and φ2 = 45 °, and 1 In the embodiment of FIG. 5 having three bent portions at one corner portion, it is preferable that, 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 showing an example of a bent portion (curved portion) of a grain-oriented electrical steel sheet. The bending angle of the bent portion means the angle difference generated between the straight portion on the rear side and the straight portion on the front side in the bending direction in the bent portion of the directional electromagnetic steel plate. The angle of the complementary angle formed by the two virtual lines Lb-elongation1 and Lb-elongation2 obtained by extending the straight line portions adjacent to both sides (point F and point G) of the curved portion included in the line Lb representing the outer surface. Expressed as φ.
The bending angle of each bent portion is less than 90 °, and the total bending angle of all the bent portions existing in one corner portion is 90 °.

In the present invention, the bent portion is a point D and a point E on the line La representing the inner surface of the grain-oriented electrical steel sheet and a point on the line Lb representing the outer surface of the grain-oriented electrical steel sheet in the side view of the grain-oriented electrical steel sheet. When F and point G are defined as follows, a line separated by points D and E on the line La representing the inner surface of the grain-oriented electrical steel sheet, and a point on the line Lb representing the outer surface of the grain-oriented electrical steel sheet. A line separated by F and a point G, a straight line connecting the point D and the point E, and a region surrounded by a straight line connecting the point F and the point G are shown.

Here, the points D, E, F, and G are defined as follows.
The center point A of the radius of curvature in the curved portion included in the line La representing the inner surface of the directional electromagnetic steel plate and the straight portion adjacent to both sides of the curved portion included in the line Lb representing the outer surface of the directional electromagnetic steel plate are extended. The point where the straight line AB connecting the intersection points B of the two virtual lines Lb-elongation1 and Lb-elongation2 obtained above intersects with the line representing the inner surface of the directional electromagnetic steel plate is defined as the origin C.
A point D is defined as a point separated from the origin C by a distance m represented by the following equation (2) in one direction along the line La representing the inner surface of the grain-oriented electrical steel sheet.
A point E is defined as a point separated by the distance m in another direction along the line La representing the inner surface of the grain-oriented electrical steel sheet from the origin C.
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 intersection with the virtual line be the 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 point F be the intersection with the virtual line.
Equation (1): m = r × (π / 4)
(In the equation (1), m represents the distance from the point C, and r represents the distance (radius of curvature) 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, it represents the radius of curvature on the inner surface side in the side view of the bent portion. The smaller the radius of curvature r, the steeper the bending of the curved portion of the bent portion, and the larger the radius of curvature r, the gentler the bending of the curved portion of the bent portion.
In the wound steel 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 some error. If there is an error, the radius of curvature of each bent portion is specified as the average value of the radius of curvature of each of the laminated steel sheets. If there is an error, the error is preferably 0.1 mm or less.
The method for measuring the radius of curvature of the bent portion is not particularly limited, but it can be measured by observing at 200 times using a commercially available microscope (Nikon ECLIPSE LV150), for example.
In the present invention, the radius of curvature r of the bent portion is set to a range of more than 1 mm and less than 3 mm, and is combined with a specific grain-oriented electrical steel sheet whose magnetic domain is controlled by the minute strain described below to reduce iron loss. It became possible to obtain.

6 and 7 are diagrams schematically showing an example of one layer of grain-oriented electrical steel sheet 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 has a corner portion 3 composed of two or more bent portions 5 and a flat portion. 4 is formed, and a substantially rectangular ring is formed in a side view through a joint portion 6 of the widthwise end faces of one or more grain-oriented electrical steel sheets.
In the present invention, the wound iron core main body may have a laminated structure having a substantially rectangular side view as a whole. As shown in the example of FIG. 6, one grain-oriented electrical steel sheet may form one layer of the wound steel core body via one joint portion 6, and is shown in the example of FIG. As described above, one grain-oriented electrical steel sheet constitutes about half the circumference of the wound core, and two grain-oriented electrical steel sheets form one layer of the wound core body via the two joints 6. There may be.
As another example, when two grain-oriented electrical steel sheets form one layer of the wound steel core body, a bent body corresponding to three sides of a substantially rectangular shape and a straight line corresponding to the remaining one side ( Steel plates (with a straight side view) may be combined to form a substantially rectangular ring. In this way, when two or more grain-oriented electrical steel sheets form one layer of the wound steel core body, a bent steel sheet and a straight (straight side view) steel sheet may be combined. As yet another example, a grain-oriented electrical steel sheet having a length of two or more layers of a wound steel core body is bent to form a bent body in which a substantially rectangular ring is continuous for two or more turns. It may be stacked in the plate thickness direction.
In either case, in order to prevent a gap between two adjacent layers during the production of the wound iron core, the outer peripheral length of the flat surface portion 4 of the grain-oriented electrical steel sheet arranged inside in the adjacent two-layer grain-oriented electrical steel sheet The length of the steel sheet and the position of the bent portion are adjusted so that the inner peripheral lengths of the flat surface portions 4 of the grain-oriented electrical steel sheets arranged on the outside are equal.

The 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 intended use, etc., but is usually in the range of 0.15 mm to 0.35 mm, preferably in the range of 0.15 mm to 0.35 mm. It is in the range of 0.18 mm to 0.23 mm.

2. Configuration of grain-oriented electrical steel sheet Next, the configuration of grain-oriented electrical steel sheet constituting the wound steel core body will be described. The directional electromagnetic steel plate used in the present invention has a surface having a 180 ° magnetic wall parallel to the longitudinal direction, which is composed of steel plate surfaces on the inner surface side and the outer surface side, and has dimensions of 150 μm or less in the longitudinal direction and dimensions in the plate thickness direction. The reflux magnetic domain having a diameter of 30 μm or more has a region in which the reflux magnetic domain 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 in which the reflux magnetic domain exists is on the inner surface side or the outer surface side. It occupies more than 25% of the surface surface surface surface of the steel plate.

(1) Region in which a specific recirculated magnetic domain exists Generally, in a grain-oriented electrical steel sheet, the orientation of crystal grains in the steel sheet is highly integrated in the {110} <001> orientation, and the easy-magnetizing axes are aligned in the longitudinal direction. A steel plate. An electromagnetic steel sheet having the property of having little iron loss and excellent magnetism because the axes that are easily magnetized are aligned in the longitudinal direction.
On the other hand, in grain-oriented electrical steel sheets, it is known that a striped magnetic domain structure called a main magnetic domain, which is divided by 180 ° domain walls parallel to the surface in the longitudinal direction, is observed. Here, the width of the main magnetic domain is determined so as to minimize the domain wall and the static energy, and there is a proportional relationship that the wider the main magnetic domain, the larger the iron loss of the electrical steel sheet. 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 of introducing strain into the surface of the steel sheet to control the magnetic domain is known. In Patent Document 1 described above, laser irradiation is performed. The width of the main magnetic domain is subdivided by the formed reflux magnetic domain, and the improvement of iron loss is achieved.

In the present invention, on a surface composed of steel plate surfaces on the inner surface side and the outer surface side and having a 180 ° magnetic domain wall parallel to the longitudinal direction, the dimension in the longitudinal direction is 150 μm or less and the dimension in the plate thickness direction is 30 μm or more. Use a grain-oriented electrical steel sheet in which a recirculation domain wall exists.
In the present invention, a grain-oriented electrical steel sheet having a reflux magnetic domain (hereinafter, may be referred to as a "specific reflux magnetic domain") having a longitudinal dimension of 150 μm or less and a plate thickness direction of 30 μm or more is used. By setting the radius of curvature r of the bent portion to a range of more than 1 mm and less than 3 mm, it is possible to obtain a wound steel core having a low iron loss without removing the strain of the bent portion by annealing. Here, in the present invention, the reflux magnetic domain refers to an auxiliary magnetic domain of a type that refluxes the magnetization of the main magnetic domain.
The method for measuring the dimensions in the longitudinal direction of such a recirculated magnetic domain is not particularly limited, and examples thereof include a method of observing and measuring using reflected electrons of an SEM (magnetic domain SEM).
In addition, there is no limitation on the method of measuring the dimensions in the plate thickness direction, but for example, etching is performed with nitric acid on the surface layer of the steel sheet, and the confirmation is made by checking whether the magnetic domain on the surface layer is observed by the magnetic domain SEM at a certain depth. (Hereinafter, it may be referred to as an etching method).

Further, the method of forming such a reflux magnetic domain is not particularly limited, but since it is easy to control the dimensions of the reflux magnetic domain, it is preferable to introduce strain by laser irradiation to form the reflux magnetic domain. For example, when a pulsed laser is used, the dimensions in the longitudinal direction can be controlled by irradiating the laser beams so as to overlap each other, and the dimensions in the depth direction can be controlled by adjusting the irradiation diameter.
Such strain 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 the energy density (mJ / mm ² ), which is the irradiation energy per unit area, and the strain introduction efficiency is higher when the laser is irradiated with a higher energy density. The energy density may be, for example, 80 mJ / mm ² .
The longitudinal dimension and the plate thickness direction of the reflux magnetic domain due to laser irradiation can be controlled by, for example, 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 ranges of 70 to 530 μm and 200 to 10,000 μm, respectively.
Therefore, in order to introduce the optimum reflux magnetic domain by laser irradiation, the spot diameter has no effect if the length of the longitudinal direction L is too short, and if it is too long, the characteristics are adversely affected. With respect to the width direction C, if it is too short, there is no effect, and if it is too long, there is no adverse effect on the characteristics, but since the total amount of energy input is too large, there is an optimum value from the viewpoint of cost.
The effect of obtaining a wound core with low iron loss without removing the strain 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 it has a magnetic domain subdivision 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 core having low iron loss without removing the strain of the bent portion by annealing, the dimension in the plate thickness direction of the reflux magnetic domain is not particularly limited as long as it is 30 μm or more, but it is more than 50 μm. The dimension of the reflux magnetic domain in the plate thickness direction is preferably 50 μm or less, and more preferably 35 to 45 μm, because the effect is saturated even if the depth is increased.

Further, in the present invention, a region in which specific reflux magnetic domains are 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 on the surface composed of the steel plate surfaces on the inner surface side and the outer surface side. A directional electromagnetic steel sheet having (hereinafter, sometimes referred to as a "specific reflux magnetic domain region") and having the region occupying 25% or more of the surface area of the steel sheet on the inner surface side or the outer surface side is used.
In the present invention, there is a region on the surface composed of the steel plate surfaces on the inner surface side and the outer surface side, in which specific perfusion magnetic zones are 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. However, using a grain-oriented electrical steel sheet in which the region occupies 25% or more of the surface area of the steel sheet on the inner or outer surface side, the radius of curvature r of the bent portion shall be in the range of more than 1 mm and less than 3 mm. As a result, it has become possible to obtain a wound steel core with low iron loss without removing the strain of the bent portion by annealing.
Since a wound core with low iron loss can be obtained, the region where the specific reflux magnetic domain exists preferably occupies 50% or more of the surface area of the steel sheet on the inner surface side or the 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 composed of the steel plate surfaces on the inner surface side and the outer surface side, and is a concept that does not include the region existing on the surface in the plate thickness direction (hereinafter,). The surface composed of the steel plate surfaces on the inner surface side and the outer surface side is simply the "steel plate surface" and the steel plate surface on the inner surface side, and the "steel plate inner surface" and the steel plate surface on the outer surface side are simply ". It may be referred to as "outer surface of steel plate").

As described above, since a wide main magnetic domain is formed on the surface of the grain-oriented electrical steel sheet in parallel with the longitudinal direction, a reflux magnetic domain is formed by introducing minute strain on a straight line parallel to the width direction of the electrical steel sheet. Is formed to subdivide the main magnetic domain.
FIG. 9 shows a schematic view of a region where a specific reflux magnetic domain exists on the surface of the steel sheet.
In order to efficiently subdivide the main magnetic domain by the reflux magnetic domain, a reflux magnetic domain is continuously formed on a straight line parallel to the width direction of the electromagnetic steel plate and drawn with respect to the entire width, and this work is performed in the longitudinal direction. By repeating this, a specific reflux magnetic domain region on the surface of the steel plate is formed.
Therefore, in the present invention, first, when the origin is set 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 in which the specific reflux magnetic zone 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 in which the specific reflux magnetic region exists is defined as lM, and the region between the straight line l and the straight line lM is specified. It is defined as the region where the reflux magnetic zone exists.
It should be noted that the presence of a reflux magnetic zone means that a straight line in which a specific reflux magnetic zone is formed between the straight line l and the straight line lM (in the x-axis direction) exists at intervals of 0.5 to 8 mm and is in the straight line (y-axis). There is no particular limitation as long as the specific perfusion magnetic zone continuously exists in the direction).
When a plurality of specific reflux magnetic domain regions are separately present in one steel sheet at intervals exceeding 8 mm, the region area is the sum of the respective region areas. Further, a region in which the distance between the straight line l and the straight line lM (in the 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 surface area of the steel plate surface 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. In addition, there may be a plurality of them separately.
Since the effect of reducing iron loss of the wound iron 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 sheet.
It is known that in an electromagnetic steel sheet to which fine strain is introduced, iron loss decreases with the tension of the surface, and in an electromagnetic steel sheet processed to form a ring, the outer surface side surface is larger than the inner surface side surface. This is because a strong tension is generated.

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

The chemical composition of the base steel plate is not particularly limited, but 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 preferably contains 015% and the balance consists of Fe and impurities. The chemical composition of the mother steel sheet is a preferable chemical component for controlling the crystal orientation to the Goss texture integrated in the {110} <001> orientation. Among the elements in the base steel sheet, 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, it is not necessary to limit the lower limit value, and it is not necessary to substantially contain them. Moreover, even if these selective elements are contained as unavoidable impurities, the effect of the present invention is not impaired. In the base steel sheet, the balance of the basic element and the selective element consists of Fe and unavoidable impurities.
In the present invention, the "unavoidable impurity" means an element that is unavoidably mixed from ore, scrap, or the manufacturing environment as a raw material when the base steel sheet is industrially manufactured.
In addition, grain-oriented electrical steel sheets generally undergo purification annealing during secondary recrystallization. In the purification annealing, the inhibitor-forming element is discharged to the outside of the system. In particular, the concentrations of N and S are significantly reduced to 50 ppm or less. Under normal purified annealing conditions, it reaches 9 ppm or less, further 6 ppm or less, and if purified annealing is sufficiently performed, it reaches a level that cannot be detected by general analysis (1 ppm or less).
The chemical composition of the base steel sheet may be measured by a general method for analyzing steel. For example, the chemical composition of the mother steel sheet may be measured using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrum). Specifically, for example, a 35 mm square test piece is obtained from the center position of the mother steel plate after the coating is removed, and under the conditions based on the calibration curve prepared in advance by Shimadzu ICPS-8100 or the like (measuring device). It can be identified by measuring. In addition, C and S may be measured by using the combustion-infrared absorption method, and N may be measured by using the inert gas melting-thermal conductivity method.
The chemical component of the grain steel sheet is a component obtained by analyzing the component of the grain steel sheet from which the glass film and the phosphorus-containing film described later are removed from the grain-oriented electromagnetic steel sheet by the method described later as the grain steel sheet.

The method for producing the grain steel sheet is not particularly limited, and a conventionally known method for producing a grain-oriented electrical steel sheet can be appropriately selected. As a preferable specific example of the production method, for example, C is 0.04 to 0.1% by mass, and the other slabs having the chemical composition of the mother steel sheet are heated to 1000 ° C. or higher for hot rolling. If necessary, hot-rolled sheet is annealed, and then a cold-rolled steel sheet is obtained by cold-rolling once or two or more times with intermediate annealing in between, and the cold-rolled steel sheet is made into, for example, 700 in a wet hydrogen-inert gas atmosphere. Examples thereof include a method of decarburizing and annealing by heating to ~ 900 ° C., further nitriding and annealing if necessary, and finishing annealing at about 1000 ° C.
In the present invention, the thickness of the mother 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 effect of the present invention is not impaired. Examples of such a coating include a glass coating formed on the mother steel plate. The glass coating has, for example, one or more oxides selected from forsterite (Mg ₂ SiO ₄ ), spinel (Mg Al ₂ O ₄ ), and cordierite (Mg ₂ Al ₄ Si ₅ O ₁₆ ). A coating may be mentioned.

The method for forming the glass film is not particularly limited, and a known method can be appropriately selected. For example, in a specific example of the method for producing a mother steel sheet, after applying an annealing separator containing at least one selected from magnesia (MgO) and alumina (Al ₂ O ₃ ) to a cold-rolled steel sheet, the finishing Examples include a method of annealing. The annealing separator also has the effect of suppressing sticking between steel sheets during finish annealing. For example, when the annealing separating agent containing magnesia is applied and finish annealing is performed, a glass film containing forsterite (Mg ₂ SiO ₄ ) is formed on the surface of the mother steel sheet by reacting with silica contained in the mother steel sheet. Ru.
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. 3. Method for manufacturing a wound iron core The method for producing a wound iron core according to the present invention is not particularly limited as long as the wound iron core according to the present invention can be manufactured, but usually, the steel plate surfaces on the inner surface side and the outer surface side of the directional electromagnetic steel plate. On a surface having a 180 ° magnetic wall parallel to the longitudinal direction, reflux magnetic sections having a longitudinal dimension of 150 μm or less and a plate thickness direction of 30 μm or more are spaced by 0.5 mm or more and 8 mm or less in the longitudinal direction. A step of preparing a directional electromagnetic steel plate having a region that exists continuously and linearly in the width direction and the region where the reflux magnetic region exists occupies 25% or more of the surface surface surface surface of the steel plate on the inner surface side or the outer surface side. By bending at least two places for each corner forming region allocated in advance on the directional electromagnetic steel plate to form a bent portion having a radius of curvature r of more than 1 mm and less than 3 mm, the direction The bending processed body is a step of forming a sex electromagnetic steel plate into a bent body in which flat surfaces and corner portions are alternately continuous and the angle formed by two adjacent flat surfaces at each corner portion is 90 °. The step of forming the bent body, which comprises a step of aligning the corner portions of the directional electromagnetic steel plates and laminating them in the plate thickness direction to form a substantially rectangular laminated body in a side view. It can be efficiently manufactured later by a manufacturing method that does not have a annealing step.
Hereinafter, the method for manufacturing the wound iron core will be described in detail in order.

First, the surface having a 180 ° domain wall parallel to the longitudinal direction, which is composed of the inner surface side and the outer surface side of the directional electromagnetic steel plate, has a longitudinal dimension of 150 μm or less and a plate thickness direction of 30 μm or more. The reflux domain walls have regions that exist 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 regions occupy 25% or more of the surface surface surface of the steel plate on the inner surface side or the outer surface side. Prepare a directional electromagnetic steel plate. 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, the description thereof is omitted here.

Next, after cutting the grain-oriented electrical steel sheet to a desired length, at least two corners are bent in each corner forming region allocated in advance on the grain-oriented electrical steel sheet to obtain a radius of curvature r of 1 mm. By forming a bent portion that exceeds and is less than 3 mm, the flat surface portion and the corner portion are alternately continuous from the grain-oriented electrical steel sheet, and the angle formed by the two adjacent flat surface portions at each corner portion is formed. A bent body at 90 ° is formed.
The bending method will be described with reference to the drawings. FIG. 10 is a schematic view showing an example of a bending processing method in a method for manufacturing a wound iron core.
The configuration of the processing machine is not particularly limited, but for example, as shown in FIG. 10A, it usually has a die 22 and a punch 24 for press working, and further, a grain-oriented electrical steel sheet 21. It has a guide 23 and the like for fixing the. The grain-oriented electrical steel sheet 21 is transported in the transport direction 25 and fixed at a preset position (FIG. 10 (B)). Next, by pressurizing the punch 24 with a predetermined force set in advance, a bent body having a bent portion having a bending angle φ can be obtained.
There is no particular limitation on the method of setting the radius of curvature r of the bent portion to a range of more than 1 mm and less than 3 mm, but 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 radius of curvature r of the bent portion can be adjusted to the above-mentioned specific range.
The radius of curvature r at the bent portion of each grain-oriented electrical steel sheet laminated in the plate thickness direction is set to match, but the radius of curvature of the processed steel sheet has an error depending on the roughness and shape of the surface layer of the steel sheet. 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 it can be measured, for example, by observing at 200 times using a commercially available microscope (Nikon ECLIPSE LV150).

Usually, in the manufacturing process of the wound iron core, a step of removing the strain of the bent portion by annealing after the bending process is indispensable.
In the present invention, the surface having a 180 ° magnetic wall parallel to the longitudinal direction, which is composed of the inner surface side and the outer surface side of the directional electromagnetic steel plate, has a longitudinal dimension of 150 μm or less and a plate thickness direction of 30 μm. The above reflux magnetic sections have regions that exist 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 regions are 25% of the surface surface surface of the steel sheet on the inner surface side or the outer surface side. By adjusting the radius of curvature r of the bent portion to a range of more than 1 mm and less than 3 mm by using the directional electromagnetic steel sheet occupying the above, the effect of canceling the strain generated during the bending process can be obtained. It is possible to obtain a wound steel core with low iron loss without going through the step of removing the strain of the bent portion by annealing.

Next, the grain-oriented electrical steel sheets, which are the bent bodies, are laminated by aligning the corners with each other and superimposing them in the plate thickness direction to form a substantially rectangular laminated body in the side view. Can be obtained. The obtained wound iron core body may be used as a wound iron core as it is, but may be further fixed with a known fastener such as a binding band or the like to be used as a wound iron core, if necessary.

The present invention is not limited to the above embodiment. The above-described embodiment is an example, and any object having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is the present invention. Is included in the technical scope of.

Hereinafter, the technical contents of the present invention will be further described with reference to examples of the present invention. The conditions in the examples shown below are examples of conditions adopted for confirming the feasibility and effect of the present invention, and the present invention is not limited to this example of conditions. Further, the present invention can adopt various conditions as long as the gist of the present invention is not deviated and the object of the present invention is achieved.
In the description of the following examples, "the ratio of the specific reflux magnetic domain region to the surface area of the steel plate surface on the inner surface side or the outer surface side" may be referred to as "occupancy rate of the specific reflux magnetic domain region".

1. 1. Examination of the relationship between the dimensions of the reflux magnetic domain and the radius of curvature of the bent portion (Example 1)
A grain-oriented electrical steel sheet having a glass coating containing forsterite (Mg ₂ SiO ₄ ) was prepared on the base steel sheet. 100% of the surface area of the steel sheet on the outer surface side (hereinafter, may be referred to as the occupancy of the irradiation region) with respect to the surface on the outer surface side of the annular structure after bending the grain-oriented electrical steel sheet, that is, the outer surface side. The whole was irradiated with a pulsed laser continuously and linearly in the width direction at intervals of 0.5 mm in the longitudinal direction. The irradiation condition of the pulse laser was C-3 shown in Table 1.
The grain-oriented electrical steel sheet is bent while adjusting so that the radius of curvature of the bent portion is 1.25 mm, and one corner portion has two bent portions having a φ of 45 °, which are substantially rectangular in side view. A grain-oriented electrical steel sheet forming a ring of Next, by laminating the grain-oriented electrical steel sheets, a wound steel core having the dimensions shown in FIG. 11 was obtained.

(Examples 2 to 20)
In Example 1, the wound iron 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 radius of curvature of the bent portion were changed as shown in Tables 1 and 3, respectively.

(Comparative Examples 1 to 150)
In Example 1, wound iron 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 radius of curvature of the bent portion were changed as shown in Tables 1 and 3, respectively.

2. Examination of the relationship between the occupancy rate of the specific reflux magnetic domain region and the radius of curvature of the 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 occupancy rate of the pulsed laser irradiation region and the radius of curvature of the bent portion were changed as shown in Tables 1 and 4, respectively. It was.
(Comparative Examples 151 to 10)
In Example 1, the wound cores of Comparative Examples 151 to 10 were obtained in the same manner as in Example 1 except that the occupancy rate of the pulsed laser irradiation region and the radius of curvature of the bent portion were changed as shown in Tables 1 and 4, respectively. It was.

3. 3. Examination of the relationship between the longitudinal distance of the specific reflux magnetic domain and the radius of curvature of the bent portion (Examples 101 to 180)
In Example 1, the wound iron cores of Examples 101 to 180 were formed in the same manner as in Example 1 except that the irradiation interval in the longitudinal direction of the pulse laser and the radius of curvature of the bent portion were changed as shown in Tables 1 and 5, respectively. Obtained.
(Comparative Examples 311-430)
In Example 1, the wound iron cores of Comparative Examples 31 to 430 were used in the same manner as in Example 1 except that the irradiation interval in the longitudinal direction of the pulse laser and the radius of curvature of the bent portion were changed as shown in Tables 1 and 5, respectively. Obtained.

4. Examination of the effects of having the specific reflux magnetic domain region on the inner surface side and the outer surface side (Examples 181 to 192)
In the first embodiment, the radius of curvature of the bent portion is 1.5 mm, and the occupancy of the pulsed laser irradiation region on the inner surface side or the outer surface side of the grain-oriented electrical steel sheet is as shown in Table 6 below. The wound steel 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 the above was irradiated with a pulse laser at intervals of 0.5 mm.
(Comparative Examples 431 to 436)
In Example 181 the same as in Example 1 except that the irradiation conditions of the pulse laser and the occupancy rate of the pulsed laser irradiation region on the inner surface side or the outer surface side of the grain-oriented electrical steel sheet were changed as shown in Table 6 below. A wound steel core of Comparative Examples 431 to 436 was obtained.

4. Examination of the effect of iron core length (Examples 193 to 207)
In the first embodiment, the radius of curvature of the bent portion is 1.5 mm, and pulse lasers are applied at intervals of 0.5 mm so as to be 25% of the surface area of the steel sheet on the outer surface side with respect to the outer surface side surface of the grain-oriented electrical steel sheet. The wound iron 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 by irradiation.

5. Evaluation method (1) Measurement of dimensions of reflux magnetic zone The laser irradiation region prepared in the above Examples and Comparative Examples was observed with a scanning electron microscope (SEM), and the dimensions in the longitudinal direction and the plate thickness direction were observed. The dimensions of were measured. The dimensions in the plate thickness direction were 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, reflux magnetic domains having a longitudinal dimension of 150 μm or less and a plate thickness direction of 30 μm or more were confirmed on the surface of the steel sheet. Under the irradiation conditions C-3, D-3, C-4 and D-4, the laser irradiation region and the specific reflux magnetic region region coincided with each other.

(2) Building Factor The wound cores of the examples and comparative examples were measured using the exciting current method described in JIS C 2550-1 under the conditions of a frequency of 50 Hz and a magnetic flux density of 1.7 T, and each wound core was measured. was determined the iron loss value _{W a.}
Used for manufacturing cores of Examples and Comparative Examples so as to reflect the laser irradiation conditions, irradiation intervals, and occupancy of the irradiated area of the grain-oriented electrical steel sheet single plate constituting the cores of Examples and Comparative Examples. A grain-oriented electrical steel sheet was taken out from each hoop on which the material steel sheet was wound, and a sample having a width of 100 mm and a length of 500 mm was shear-collected. The sample was measured by an electromagnetic steel sheet single plate 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, and the wound iron cores of Examples and Comparative Examples were used. 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 Is shown. Irradiation conditions C-3, D-3, C-4 and D-4 material steel sheets in which reflux magnetic domains having a longitudinal dimension of 150 μm or less and a plate thickness direction of 30 μm or more were confirmed on the surface of the steel sheet, etc. in comparison with the steel sheet, it has been confirmed that low iron loss value W _B.
The iron loss value W _A of the wound core was determined building factor (BF) divided by the iron loss value W _B of the electromagnetic steel veneer. In the present invention, it can be evaluated that the smaller the BF, the smaller the influence of the bending process on the material steel sheet. Further, if the BF of the wound iron core manufactured by using the low iron loss steel sheets under the irradiation conditions C-3, D-3, C-4 and D-4 is low, the iron loss is compared with that of the conventional wound iron core. Can be evaluated as a wound steel core with reduced.

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

On the other hand, the laser was found under the conditions of C-3, C-4, D-3 and D-4 in which reflux magnetic domains having a longitudinal dimension of 150 μm or less and a plate thickness direction of 30 μm or more were confirmed on the surface of the steel sheet. In the iron cores of Examples 1 to 20 manufactured by setting the radius of curvature r to 1.25 mm or more and 2.9 mm or less using the irradiated steel sheet, the BF is 1.01 or less, and the material steel sheet is bent. However, it became clear that the iron loss hardly worsened.

Next, Tables 4-1 to 4-4 show the results of studies on the effect of the occupancy rate (%) of the specific reflux magnetic domain region. Further, FIGS. 13 to 16 show the influence of the occupancy rate (%) of the specific reflux magnetic domain region in Tables 4-1 to 4-4.
As shown in FIG. 13, a radius of curvature r is set to 1 by using a steel sheet irradiated with a laser under the condition of C-3 in which a reflux magnetic domain having a longitudinal dimension of 150 μm and a plate thickness direction of 30 μm was confirmed on the surface of the steel sheet. In a wound steel core manufactured with a setting of .25 mm or more and 2.9 mm or less, even if the occupancy rate of the specific reflux magnetic domain region on the outer surface side surface of the steel sheet is 10 to 20%, the iron loss is deteriorated by bending the material steel sheet. Although this was suppressed to some extent, the 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 the wound iron core manufactured by setting the radius of curvature r to 1.25 mm or more and 2.9 mm or less using a steel plate having a specific reflux magnetic domain region occupancy of 25% or more on the outer surface side surface of the steel sheet, BF Was 1.02 or less, and it was clarified that the deterioration of iron loss due to bending can be suppressed almost completely.
Further, as shown in FIGS. 14 to 16, a steel sheet irradiated with a laser under the condition of D-3 in which a reflux magnetic domain having a longitudinal dimension of 50 μm and a plate thickness direction of 30 μm was confirmed on the surface of the steel sheet, in the longitudinal direction. A steel sheet irradiated with a laser under the condition of C-4 in which a recirculation magnetic domain having a dimension of 150 μm and a dimension in the plate thickness direction of 50 μm was confirmed on the surface of the steel plate, a recirculation having a dimension in the longitudinal direction of 50 μm and a dimension in the plate thickness direction of 50 μm. Similarly, in the case of a wound steel core manufactured using a steel sheet irradiated with a laser under the condition of D-4 in which magnetic domains are confirmed on the surface of the steel sheet, when the occupancy rate of the specific 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 occupancy rate of the specific magnetic domain region on the outer surface of the steel sheet is 25% or more. In this case, it was clarified that the deterioration of iron loss due to bending can be suppressed almost completely.

Next, Tables 5-1 to 5-4 show the results of studies on the influence of the spacing in the longitudinal direction of the specific reflux magnetic domains that exist continuously and linearly in the width direction. Further, FIGS. 17 to 20 show the influence of the spacing in the longitudinal direction of the specific reflux magnetic domains existing continuously and linearly in the width direction in Tables 5-1 to 5-4.
As shown in FIG. 13, a laser irradiation is performed under the condition of C-3, and the distance in the longitudinal direction of the reflux magnetic domain, which exists continuously and linearly in the width direction and has a dimension in the longitudinal direction of 150 μm and a dimension in the plate thickness direction of 30 μm. In the wound iron core of Comparative Example 331-340 manufactured using a steel plate having a radius of 9 mm, the BF was 1.15 or more even if the radius of curvature r was set to 1.25 mm or more and 2.9 mm or less, and by bending. The deterioration of iron loss that occurred could hardly be suppressed.
On the other hand, a steel plate having a longitudinal distance of 0.5 to 8 mm in the reflux magnetic domain having a longitudinal dimension of 150 μm and a plate thickness direction of 30 μm existing continuously and linearly in the width direction is used. In the manufactured rolled iron 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), the BF is 1.02 or less, and the deterioration of iron loss caused by bending is deteriorated. It became clear that it could be almost suppressed.
Further, as shown in FIGS. 18 to 20, a steel sheet irradiated with a laser under the condition of D-3 in which a reflux magnetic domain having a longitudinal dimension of 50 μm and a plate thickness direction of 30 μm was confirmed on the surface of the steel sheet, in the longitudinal direction. A steel sheet irradiated with a laser under the condition of C-4 in which a recirculating magnetic domain having a dimension of 150 μm and a dimension in the plate thickness direction of 50 μm was confirmed on the surface of the steel plate. Similarly, a wound steel core manufactured using a steel sheet irradiated with a laser under the condition of D-4 in which magnetic domains are confirmed on the surface of the steel sheet is also wound manufactured using a steel sheet having a longitudinal interval of 9 mm in the specific magnetic domain. 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, the deterioration of iron loss caused by bending can hardly be suppressed, but the interval in the longitudinal direction of the specific recirculation magnetic domain is 0. It has been clarified that in a wound steel core manufactured using a steel plate having a diameter of 5 to 8 mm, when 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 be almost suppressed. It was.

Next, Table 6 shows the results of studies on the effects of the specific reflux magnetic domain regions 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 plate thickness direction of 30 μm exists on the surface of the steel sheet, a specific reflux magnetic 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 having an occupancy rate of less than 25%, the BF was 1.03 or more, and a low iron loss wound core could not be obtained.

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

Here, when the wound cores of Examples 181 to 188 are compared under the condition that the occupancy rate of the specific reflux magnetic domain region is the same, 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 the values were 01 to 1.03.
Therefore, it was clarified that in the electrical steel sheets having the same occupancy of the specific reflux magnetic domain region, the effect of suppressing the deterioration of iron loss caused by the bending process is higher when the specific reflux magnetic domain region is arranged on the outer surface side.
Further, in the wound cores of Examples 181 to 184 in which the specific reflux magnetic domain region is arranged on the outer surface side and the wound cores of Examples 189 to 192 in which the specific reflux magnetic domain regions are arranged on both sides, the specific reflux magnetic domain region on the outer surface side. Since the BFs were almost the same when compared under the same conditions, even if the specific reflux magnetic domain region was arranged on the outer surface side, the BF was further arranged on the inner surface side. It became clear that there was 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 iron cores of Examples 203 to 207 having an iron core length of 1.5 m or more have a BF of 0.92 or less and an iron core length of less than 1.5 m, windings of Examples 193 to 202. It became clear that the BF was lower than that of the iron core.

Based on the above results, the wound iron core includes a wound core body having a substantially rectangular shape in a side view, and the wound core body has flat surfaces and corners alternately continuous in the longitudinal direction and adjacent to each corner. The directional electromagnetic steel plates having an angle of 90 ° formed by the two plane portions include a portion 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 sex electromagnetic steel plate, it has two or more bent portions having a curved shape, and the total bending angle of each of the bent portions existing in one corner portion is 90 °. The radius of curvature r on the inner surface side in the side view of the portion exceeds 1 mm and is less than 3 mm, and is composed of the inner surface side and outer surface side steel plate surfaces of the directional electromagnetic steel plate and has a 180 ° magnetic wall parallel to the longitudinal direction. , The reflux magnetic section having a longitudinal dimension of 150 μm or less and a plate thickness direction of 30 μm or more has a region in which the reflux magnetic section 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. It is clear that the wound iron core of the present invention has a low iron loss property, characterized in that the region where the reflux magnetic zone exists occupies 25% or more of the surface surface surface surface of the steel plate on the inner surface side or the outer surface side. It became.

1, 1a Electrical steel sheet 2 Laminated body 3 Corner parts 4, 4a, 4b Flat parts 5, 5a, 5b, 5c Bent parts 6 Joints 10 Winding core body (rolled core)
21 Directional electromagnetic steel plate 22 Dice 23 Guide 24 Punch 25 Transport direction 26 Pressurization direction

Claims (3)

A wound iron core having a substantially rectangular wound core body when viewed from the side.
In the main body of the wound iron core, flat surfaces and corners are alternately continuous in the longitudinal direction, and a grain-oriented electrical steel sheet having an angle formed by two adjacent flat surfaces at each corner at 90 ° is formed in the thickness direction. Including the stacked parts, it has a substantially rectangular laminated structure in the side view.
Each of the corners 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 of the bent portions existing in one corner is the sum. 90 °
The radius of curvature r on the inner surface side in the side view of the bent portion exceeds 1 mm and is less than 3 mm.
Circulation having a lengthwise dimension of 150 μm or less and a plate thickness direction of 30 μm or more on a surface composed of steel plate surfaces on the inner surface side and the outer surface side of the directional electromagnetic steel plate and having a 180 ° domain wall parallel to the longitudinal direction. The domain walls have regions that exist continuously and linearly in the width direction at intervals of 0.5 mm or more and 8 mm or less in the longitudinal direction.
A wound iron core, characterized in that the region where the reflux magnetic domain exists occupies 25% or more of the surface area of the steel plate surface on the inner surface side or the outer surface side. The wound steel core according to claim 1, wherein the region in which the reflux magnetic domain exists is provided on the surface of the steel sheet on the outer surface side of the grain-oriented electrical steel sheet. The wound iron core according to claim 1 or 2, wherein the iron core length of the wound iron core body is 1.5 m or more.