JP2006332235A - Winding iron core - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce magnetic path and also reduce loss of a cut-core, of which the joining system is the lap bonding system. <P>SOLUTION: Both sides of side 12a where the butting portions of steel plates exist, and side 12b facing to the side 12a in the winding iron core 12 of a polygonal shape, are respectively defined as diagonal sides 12c, 12d. Thus, the magnetic path can be reduced more than that of the related art where this part is formed as an arcuate part. Moreover, length C<SB>11</SB>of at least one diagonal sides 12c of the diagonal sides 12c on both sides of the side 12a, where the butting portion exists is set shorter than the length C<SB>12</SB>of the other diagonal side 12d. Accordingly, the number of sheets of the long-distance area can be reduced between the butting portions, and thereby, loss can also be reduced. In addition, since the length C<SB>12</SB>of the diagonal side 12d, other than the diagonal side 12c where the length C<SB>11</SB>is reduced, can be set as the maximal value, length of steel plate can be shortened, namely magnetic path can be reduced, and thereby loss can also be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wound core having a so-called cut core and a joining method of a lap joining method.

  Conventionally, for example, a wound core type transformer 1 shown in FIG. 5 is composed of a polygonal wound core 2 having a predetermined window hole size and a coil 3 mounted on both legs 2a thereof. In order to obtain the wound iron core 2, first, a strip-shaped electromagnetic steel sheet (generally a ribbon of silicon steel sheet) is initially wound into a circular shape a predetermined number of times.

  As described above, the wound core 2 is one in which the coils 3 are respectively sheathed on both leg portions 2a. In order to be able to do so, the wound core 2 is generally folded in the above-described circular shape. A unit iron core is used as a one-turn cut shape that is cut at one place for each turn, and a plurality of unit iron cores are abutted at the respective cut ends, and then formed into a polygonal shape such as the illustrated rectangle. Although it is preferable not to cut the wound core 2 in consideration of the core characteristics of the transformer 1, it is necessary for the combination with the coil 3.

  The magnetic flux passing through the steel sheet of the wound core 2 forms a closed loop as a whole, but a gap is inevitably generated at the butt portion, and since this gap has a large resistance to make a magnetic path, the magnetic flux passes through the gap. First, a magnetic path passing through another adjacent steel plate is created to form a closed loop. At this time, if the abutting portions of adjacent steel plates are aligned at the same position in the winding direction, the magnetic path is not ensured and the magnetic path is disturbed to increase the loss, or the restoration that tries to extend from the winding state of the steel plate Since it is difficult to keep abutting the cut end of the steel sheet due to the force and the unwinding bulge of the entire wound core 2 occurs, the number of the butted parts of adjacent steel sheets is the minimum necessary number [mm The lap joining method is adopted in which the portions near the cut end portion of the steel plate overlap each other by shifting by a certain distance.

When assembling the transformer 1, first, the coil 3 is arranged at a predetermined position, and the wound core 2 opened from the cutting portion is inserted into the arranged coil 3, and after the insertion, the wound core 2 is closed and each cutting is performed. Assembling is performed by a method in which the end portions are rebutted, but in order to assemble in this way, the abutting portion of the wound core 2 must exist only on one side of the polygonal wound core 2. However, since the number of times of winding the steel sheet of the wound core 2 is as high as several tens to several hundreds, in order to fit the entire position of the butt portion within the range of the dimension of one side of the polygonal wound core 2, 6, the number of windings of the steel plate 4 in which the entire position of the butt portion 5 fits within the range of the dimension of one side of the wound core 2 while shifting the position of the butt portion 5 of the cut steel plate 4 by a predetermined distance L. A block B ₁ is used, and a plurality of blocks B ₁ are stacked.
Issued by Nikkan Kogyo Shimbun Electric Power Equipment Course 5 Transformer Page 83 Figure 3.7 Winding Iron Core (c) Lap Joint

In the case of the above-described conventional one, the shape of the wound core 2 is rectangular as shown in FIG. 5, the side where the butted portion 5 exists (the lower side in the figure), and the side facing the side (in the figure) , And the upper side) are arc-shaped portions having a radius R.
In the entire iron core, reducing the length of the magnetic path, that is, the steel plate as much as possible is effective in reducing the loss. Therefore, not only the size of the entire iron core is reduced, but also magnetic path reduction (shortening of the steel plate length) is achieved by maximizing the radius R of each arc-shaped portion.
However, the arc-shaped portion having the radius R has a limit in reducing the magnetic path.

On the other hand, as shown in FIG. 6, in the side portion where the butt portion 5 exists, the butt portion 5 is displaced by a distance L of a predetermined number [mm] in one block B _1. but butted portion 5 of one of the outermost layer of the block B ₁ steel 4, the butted portion 5 of the outermost steel sheet 4 of the other blocks B ₁ adjacent, largely deviated as indicated by the distance M.

  Also, as shown in FIG. 7, the magnetic flux φ passing through a certain steel plate 4 is difficult to pass through the gap g of the abutting portion 5 as described above, so it moves to the adjacent steel plate 4 to form a magnetic path, and finally A closed loop passing through the entire wound core 2 is formed. At this time, when the magnetic flux φ shifts to the adjacent steel plate 4, the density of the magnetic flux φ increases in the transferred steel plate 4 as indicated by a thick line in FIG. 7.

Here, the loss of the iron core 2 of the transformer 1 varies depending on the density of the magnetic flux φ passing through the steel plate 4 and increases as the density of the magnetic flux φ increases as shown in FIG. At the same time, in the steel plate 4 adjacent to the other block B ₁ , the distance between the butt portions 5, that is, the dimension of the high density portion of the magnetic flux φ is long as indicated by M in FIG. The amount was also large.

In particular, in the transformer of small capacity, because the length of one side portion of the winding core 2 is small, the greater the number of blocks B _1, high density of the above magnetic flux phi, and, in many cases a large part of the length Therefore, the increase in loss was even greater.
As a cause of the loss of the transformer, except for the iron loss as a characteristic of the magnetic steel sheet of the iron core material, the butt portion 5 has a great influence, and the butt portion 5 is required to reduce the loss of the entire transformer. Reducing the loss increase rate is a major issue.

  The present invention has been made in view of the above-mentioned circumstances, and therefore the object thereof is to reduce the magnetic path, and at the same time, a wound core that can further reduce the loss of the cut core and the lap joint type. Is in providing.

  In order to achieve the above object, in the wound iron core of the present invention, first, a belt-shaped electromagnetic steel sheet to be wound is cut into a unit iron core every one turn or a plurality of turns, and a plurality of unit iron cores are provided. In each of the wound cores that are abutted at the cut ends, the abutted portions are shifted in the winding direction and rolled up, and formed into a polygonal shape, the side where the abutted portion exists and the side opposite to the side Each of the two sides of the slanted side of the side where the butted portion is present, and the length of at least one of the slanted side is shorter than the length of the other side of the slanted side. It is characterized (Invention of Claim 1).

  In the wound iron core of the present invention, secondly, the belt-shaped electromagnetic steel sheet to be wound is cut every turn or every plurality of turns to make unit iron cores, and a plurality of unit iron cores are abutted at the cut ends. In the wound core formed by shifting the butted portion in the winding direction and forming it into a polygonal shape, both sides of the side where the butted portion exists and the side facing the side are hypotenuse And the inclination angle of at least one of the oblique sides on both sides of the side where the butted portion exists is greater than 45 degrees (invention of claim 2).

  According to the first means (invention of claim 1), both sides of the side where the butted portion is present and the side opposite to the side of the electromagnetic steel sheet in the wound iron core are oblique sides, In short, since it is a linear part, the magnetic path can be reduced as compared with the conventional part that was an arc part.

  In addition, the side where the butted portion exists is equivalent to the length of at least one of the hypotenuses on both sides of the side where the butted portion of the electromagnetic steel sheet is present is shorter than the length of the other hypotenuse. The length of the steel sheet becomes longer, and the number of windings of the steel sheet in which all the positions of the butted portions of the steel sheet are within the range of the dimensions can be increased. Therefore, the total number of blocks can be reduced when the number of rolled steel sheets in which all the positions of the abutting parts are accommodated is one block, and thus the number of parts with a large distance between the abutting parts is reduced, thereby reducing loss. Can do. Further, since the length of the hypotenuse other than the hypotenuse having a reduced length can be maximized, the length of the steel plate can be shortened, that is, the magnetic path can be reduced, and loss can be reduced.

  According to the second means (invention of claim 2), both sides of the side portion where the butted portion exists and the side portion facing the side portion of the magnetic steel sheet in the wound iron core are oblique sides, in short, a straight line. Therefore, the magnetic path can be reduced as compared with the conventional one in which the portion is an arcuate portion.

  In addition, by setting the inclination angle of at least one of the oblique sides on both sides of the side portion where the butt portion of the electromagnetic steel sheet is present to be greater than 45 degrees, as described above, the side portion where the butt portion is present Since the length of the steel sheet can be increased so that all the positions of the abutting portion of the steel sheet can be accommodated within the range of the dimensions, the number of windings of the steel sheet where the entire position of the abutting portion can be accommodated is one block. The total number of blocks can be reduced, the number of parts having a large distance between the butted portions is reduced, and loss can be reduced. In addition, the hypotenuse other than the hypotenuse with the inclination angle exceeding 45 degrees can reduce the loss by reducing the steel plate length, that is, reducing the magnetic path, by keeping the inclination angle to 45 degrees or less. .

Hereinafter, the present invention is applied to a wound iron core of a transformer, and a first example (first embodiment) will be described with reference to FIGS. 1 to 3.
First, FIG. 1 shows a wound iron core 12 and a coil 13 of a transformer 11. Among them, the wound iron core 12 is formed by first winding a strip-shaped electromagnetic steel sheet (generally a thin ribbon of silicon steel sheet) 14 shown in FIG. 2 into a circular shape a predetermined number of times, and one electromagnetic steel sheet 14 for each turn. The unit core 15 is made into a one-turn cut shape that is cut at a cutting end 15a, and a plurality of the unit cores 15 are butted at the cutting end 15a. The rolls are shifted by a distance L and then formed into a polygon.

And both sides of the side part (lower side part in FIG. 1) 12a where the folding and butting part 16 of the molding exists, and the other side part (upper side part in FIG. 1) 12b opposite to this side part 12a, respectively. Are the hypotenuse parts 12c and 12d. Therefore, in this case, the entire wound core 2 is formed into an octagon.
In addition, both sides of the inclined portion 12c of the side portion 12a of the abutting portion 16 is present, the length C ₁₁ has been shaped to be shorter than the length C ₁₂ other inclined portion 12d.

  Thus, in order to assemble the transformer 11 with the wound core 12, the two coils 13 are arranged at predetermined positions, and the wound core 12 opened from the above-described cutting portion is inserted into the arranged coil 13. After the insertion, the wound core 12 is closed and the cut end portions 15a are rebutted. In this relation, the butted portion 16 of the wound core 12 exists only on one side 12a of the wound core 12.

Further, the number of windings of the steel sheet 14 of the wound core 12 is several tens to several hundreds, and in order to fit the entire position of the abutting portion 16 in the range of the dimension of one side 12a of the wound core 12, FIG. As shown in the drawing, the position of the butt portion 16 of the cut steel plate 14 is shifted by the predetermined distance L, and the steel plate 14 is wound so that the entire position of the butt portion 16 falls within the range of the dimension of the one side portion 12a of the wound core 12. the number and one block B _11, employs a configuration overlaying the block B ₁₁ a plurality of stages in advance.
As a result of the assembly, the coil 13 is externally mounted on both leg portions 12e of the wound iron core 12.

  Now, in the case of the structure configured as described above, both sides of the side portion 12a of the steel sheet 4 in the wound core 12 where the butted portion 16 is present and the other side portion 12b facing the side portion 12a are respectively inclined side portions 12c, Since it is 12d, in short, it is a straight portion, the magnetic path of the wound core 12 can be reduced as compared with the conventional one in which the portion is an arc portion.

Further, the wound core 12, the length C ₁₁ on both sides of the side portions 12a of the inclined portion 12c of the abutted portion 16 is present in the steel sheet 14, and shorter than the length C ₁₂ other slant portion 12d, the Therefore, the length of the side portion 12a where the butted portion 16 is present is increased. Along with this, can increase the winding number of the steel plate 14 which all positions fits the butt portion 16 of the steel plate 14 to a range of dimensions of the side portions 12a, it can be reduced the total number of blocks B _11. As a result, as shown in FIG. 3, the number of large portions where the distance between the butting portions 16 is N, which has been the cause of the increase in the loss of the wound core 12 described above, can be reduced, and loss can be reduced. .

Further, the inclined portion 12d other than the oblique portion 12c with a reduced length C _11, because it maximizes the length C _12, shortening the length of the steel plate 14, that is, it is possible to reduce the number of the magnetic path, reduces the loss Can do.
Note that the hypotenuse part 12c on both sides of the side part 12a where the butted part 16 of the steel plate 14 of the wound iron core 12 is present is not both, but only one side is made shorter than the other hypotenuse part. However, a corresponding and sufficient loss reduction effect can be obtained.

In contrast to this, FIG. 4 shows a second embodiment (second embodiment) of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Only the part is described.
For this product, the above-mentioned, the length C ₁₁ on both sides of the inclined portion 12c of the side portion 12a of the butt portion 16 are present in the steel sheet 14 in the winding core 12, it is made shorter than the length C ₁₂ other inclined portion 12d Instead of this, the inclination angle θ of the oblique side portion 12c on both sides of the side portion 12a where the abutting portion 16 exists is set to exceed 45 degrees.

Even if it does in this way, the length of the side part 12a in which the butt | matching part 16 exists becomes long. Further, the hypotenuse part 12d other than the hypotenuse part 12c with the inclination angle exceeding 45 degrees can shorten the length of the steel sheet 14, that is, reduce the magnetic path, by keeping the inclination angle at 45 degrees or less. Thus, the same effect as the first embodiment can be obtained.
In this case as well, the oblique side portions 12c on both sides of the side portion 12a where the butted portion 16 of the steel sheet 14 of the wound core 12 is present, but not both of them, the inclination angle of only one may be more than 45 degrees. Therefore, a corresponding and sufficient loss reduction effect can be obtained.

In addition, the steel sheet 14 of the wound core 12 may be cut not every turn but every plurality of turns to make it a unit core.
Furthermore, the whole can be applied to a reactor other than a transformer, for example, a reactor.
In addition, the present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications within a range not departing from the gist.

The front view of the whole transformer which shows 1st Example of this invention Enlarged front view of the X part (main part) in FIG. Enlarged longitudinal section showing the magnetic path of the main part FIG. 1 equivalent view showing a second embodiment of the present invention. 1 equivalent diagram showing a conventional example Enlarged front view (corresponding to FIG. 2) of the Y part (main part) of FIG. 3 equivalent figure Diagram showing the relationship between magnetic flux density and loss of transformer core

Explanation of symbols

In the drawing, 12 is a wound iron core, 12a is a side where the butted portion of the wound core is present, 12b is a side facing the side where the butted portion of the wound core is present, 12c and 12d are oblique sides, 13 is a coil, 14 is a magnetic steel sheet, 15 is a unit core, 16 is a butting portion, C ₁₁ and C ₁₂ are the length of the hypotenuse, and θ is the inclination angle of the hypotenuse.

Claims (2)

The strip-shaped electrical steel sheet to be wound is cut into one or more turns to make unit iron cores, and a plurality of unit iron cores are abutted at the respective cut ends, and the abutting parts are shifted in the winding direction and wound. In wound cores that are stacked and molded into polygons,
Both sides of the side where the butt portion exists and the side opposite to the side are set as oblique sides,
A wound core characterized in that at least one of the oblique sides on both sides of the side where the butted portion is present has a shorter length than the other oblique sides. The strip-shaped electrical steel sheet to be wound is cut into one or more turns to make unit iron cores, and a plurality of unit iron cores are abutted at the respective cut ends, and the abutting parts are shifted in the winding direction and wound. In wound cores that are stacked and molded into polygons,
Both sides of the side where the butt portion exists and the side opposite to the side are set as oblique sides,
A wound iron core, wherein an inclination angle of at least one of the oblique sides on both sides of the side where the butted portion exists is greater than 45 degrees.

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