JP2018117046A - Transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transformer capable of reducing a magnet resistance in a flow of a magnetic flux of an iron core.SOLUTION: A cylindrical transformer comprises: one column iron core 2; one or two or more cylindrical iron cores 5 arranged in the circumference of the column iron core 2; two plate-like iron cores 1 connected to axial direction end parts 2a and 2b of the column iron core 2, and connected to axial direction end parts 5a and 5b of the cylindrical iron cores 5; and a primary coil 3 and a secondary coil 4 arranged between the column iron core 2 and the cylindrical iron core 5. The present invention adopts the transformer that, when a relative magnetic permeability of the column iron core 2 is μ0, a cross sectional area of the column iron core 2 is S0, the relative magnetic permeability of the k-th cylindrical iron core 5 is μk, and the cross sectional area of the k-th cylindrical iron core 5 is Sk, at least one cylindrical iron core 5 satisfies the following equation: 0.80≤(μk×Sk)/(μ0×S0)≤1.20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transformer.

  Transformers used for electrical equipment and the like are required to have higher efficiency from the viewpoint of energy saving. From such a demand, non-oriented electrical steel sheets used for iron cores such as transformers are required to have low iron loss and high magnetic flux density, and at the same time, improvements in consideration of the magnetic characteristics and the iron core structure are required.

Patent Document 1 describes a technique in which an iron core has a cylindrical gap, and magnetic flux is transmitted to the iron core across the gap by electromagnetic induction to operate as a transformer.
Patent Document 2 discloses a technique in which a coil and a cylindrical iron core are arranged concentrically, and a primary winding and a secondary winding are wound around a winding space in a concentric manner as a coil.
Further, Patent Document 3 discloses a technique for suppressing the non-uniform distribution of magnetic powder in the composite material constituting the magnetic core in the reactor.
Furthermore, Patent Document 4 discloses a technique that can effectively reduce leakage of magnetic flux when a coil is excited in a reactor.
Patent Document 5 discloses a technology related to a reactor that is gapless and excellent in assembly workability.
Furthermore, Patent Document 6 discloses a reactor in which a cylindrical coil is housed in a core including a core portion, a bottom portion, and a cylindrical portion. A core composed of a core part, a bottom part, and a cylindrical part is manufactured by mixing and dispersing magnetic powder in an insulating resin and molding them.
Further, Patent Document 7 discloses a structure in which a reactor core includes a cylindrical inner core, an outer core, and an end core, and the cylindrical portion and the end core are fitted to each other.
Further, Patent Document 8 discloses a structure in which a transformer is covered with two conductive materials so that an external magnetic field does not affect a magnetic field in an iron core in a separation transformer.
Further, Patent Document 9 discloses a method for determining a transformer constant in a transformer for switching power supply, and discloses a method of using the vacuum relative permeability of the core gap at that time.
In addition, Utility Model Registration No. 3170384 discloses a method for determining an iron core cross-sectional area in a small transformer installed in an arc tube.
However, none of the techniques described in Patent Documents 1 to 10 relate to the structure of the cylindrical transformer, and does not aim to reduce the magnetic resistance in the flow of magnetic flux in the iron core.

JP 2001-57313 A JP 2000-114063 A JP 2013-179259 A JP 2013-149943 A JP 2013-162069 A JP 2012-54483 A JP 2008-41721 A JP 2000-114077 A JP 2002-252131 A Utility Model Registration No. 3170384

Conventionally, in order to improve the characteristics of a transformer, the magnetic characteristics of an electromagnetic steel sheet are usually evaluated in a direction parallel to the plate surface of the steel sheet. Therefore, efforts to control crystal orientation have been directed to arrange the <100> direction, which is the easy axis of magnetization, in a direction parallel to the plate surface of the steel sheet.
However, it is important to design the transformer in consideration of the magnetic characteristics of the non-oriented electrical steel sheet, because the magnetic resistance, which is the ease of magnetic flux flow in the core that constitutes the transformer, is important.

  This invention is made | formed in view of the said request, and makes it a subject to provide the transformer which can equalize the flow of the magnetic flux of a cylindrical iron core, reduce magnetic resistance, and can raise efficiency.

ただし、式（１）における添字ｋは、１以上の自然数であり、柱状鉄心の最も近くに配置された筒状鉄心を１とし、柱状鉄心から離れるに従い１づつ増加した数とする。
［２］ 上記［１］の変圧器において、さらに、
一方の前記板状鉄心の比透磁率をμplate1とし、その軸方向に垂直な断面積をＳplate1とし、
他方の前記板状鉄心の比透磁率をμplate2とし、その軸方向に垂直な断面積をＳplate2としたとき、
下記式（２）及び下記式（３）が成立することを特徴とする上記［１］に記載の変圧器。

［３］ 前記柱状鉄心、前記筒状鉄心、前記板状鉄心のうち少なくとも一つが、質量％で、
０．１≦Ｓｉ≦３．５、
０．１≦Ｍｎ≦１．５、
Ａｌ≦２．５、
Ｃ≦０．００３、
Ｎ≦０．００３、
Ｓ≦０．００３、
残部がＦｅ及び不可避不純物からなる鋼材を素材とする鉄心であることを特徴とする上記［１］または［２］に記載の変圧器。
［４］ 前記鋼材が、電磁鋼板の単体または２以上の電磁鋼板の積層体であることを特徴とする上記［３］に記載の変圧器。 The gist of the present invention for solving the above problems is as follows.
[1] One columnar core, and one or more cylindrical cores arranged around the columnar core,
Two plate-like cores connected to the axial ends of the columnar core and connected to the axial ends of the cylindrical core;
A cylindrical transformer provided with a primary coil and a secondary coil disposed between the columnar iron core and the cylindrical iron core;
The relative permeability of the columnar iron core is μ0,
The cross-sectional area of the columnar core is S0,
Μk, the relative permeability of the k-th cylindrical iron core,
The cross-sectional area of the k-th cylindrical iron core is Sk,
Then, the following formula (1) is established for at least one cylindrical iron core.

However, the subscript k in the formula (1) is a natural number of 1 or more, and the cylindrical core disposed closest to the columnar core is set to 1, and the number increases by 1 as the distance from the columnar core increases.
[2] In the transformer of [1] above,
One plate iron core has a relative magnetic permeability μplate1, its cross-sectional area perpendicular to the axial direction is Splate1,
When the relative permeability of the other plate-shaped core is μplate2 and the cross-sectional area perpendicular to the axial direction is Splate2,
The following formula (2) and the following formula (3) are satisfied, the transformer according to the above [1].

[3] At least one of the columnar iron core, the cylindrical iron core, and the plate iron core is in mass%,
0.1 ≦ Si ≦ 3.5,
0.1 ≦ Mn ≦ 1.5,
Al ≦ 2.5,
C ≦ 0.003,
N ≦ 0.003,
S ≦ 0.003,
The transformer according to [1] or [2] above, wherein the balance is an iron core made of a steel material made of Fe and inevitable impurities.
[4] The transformer according to [3], wherein the steel material is a single magnetic steel sheet or a laminate of two or more electromagnetic steel sheets.

  ADVANTAGE OF THE INVENTION According to this invention, the magnetic resistance in the flow of the magnetic flux of a cylindrical iron core can be reduced, and the transformer which can raise efficiency can be provided.

FIG. 1 is an exploded perspective view showing a single-phase transformer which is an example of a transformer according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the flow of magnetic flux in the cross section of the single-phase transformer shown in FIG. Drawing 3 is a mimetic diagram showing the arrangement relation between each iron core in a cross section of a three phase transformer which is an example of a transformer of an embodiment of the present invention, and a primary coil and a secondary coil. FIG. 4 is a schematic cross-sectional view showing a single-phase transformer which is another example of the transformer according to the embodiment of the present invention.

Hereinafter, the transformer of this embodiment will be described.
FIG. 1 shows an exploded perspective view of a cylindrical single-phase transformer which is an example of the transformer of this embodiment, and FIG. 2 shows a cross-sectional view of the transformer. In FIG. 2, the flow of magnetic flux when the transformer is activated is indicated by arrows. The transformer shown in FIG. 1 and FIG. 2 is arranged so as to sandwich the columnar core 2, the cylindrical core 5 disposed concentrically around the columnar core 2, and the columnar core 2 and the cylindrical core 5 from above and below. Plate-shaped iron core 1, and primary coil 3 and secondary coil 4 arranged between columnar iron core 2 and cylindrical iron core 5.

  The cylindrical iron core 5 is disposed substantially concentrically around the columnar iron core 2. Moreover, the primary coil 3 is arrange | positioned around the columnar iron core 2, the secondary coil 4 is arrange | positioned at the outer peripheral side of the primary coil 3, and the cylindrical iron core 5 is arrange | positioned further at the outer peripheral side. The turn ratio of the primary coil 3 and the secondary coil 4 may be a turn ratio applicable to any application of voltage drop or voltage rise. Further, in order to improve the space factor of the coil, a rectangular wire or a winding having a square cross section may be used for the primary coil 3 and the secondary coil 4.

As shown in FIGS. 1 and 2, the plate-like iron core 1 is connected to the axial ends 2 a and 2 b of the columnar iron core 2. The plate-like iron core 1 is also connected to axial ends 5 a and 5 b of the cylindrical iron core 5. Here, the axial direction of the columnar core 2 is a direction parallel to the height direction of the columnar core 2, and is a direction substantially parallel to the direction in which the magnetic flux flows through the columnar core 2 when the transformer is operated. And the axial direction edge part 2a, 2b of the columnar iron core 2 is the both ends of the height direction of the columnar iron core 2, as shown in FIG.1 and FIG.2. Moreover, the axial direction of the cylindrical iron core 5 is a direction parallel to the height direction of the cylindrical iron core 5, and is a direction substantially parallel to the direction in which the magnetic flux flows through the cylindrical iron core 5 when the transformer is operated. . And the axial direction edge parts 5a and 5b of the cylindrical iron core 5 are the both ends of the height direction of the cylindrical iron core 5, as shown in FIG. 1 and FIG.
Furthermore, the axial direction of the transformer is a direction parallel to the axial direction of the columnar core 2 or the cylindrical core 5.

  In the example shown in FIGS. 1 and 2, the number of cylindrical iron cores 5 is one, but as shown in FIG. 3 described later, the number of cylindrical iron cores in the transformer of the present invention is limited to one. It may be two or more.

  The transformer according to the present invention is characterized by facilitating the flow of magnetic flux in an iron core in a single-phase or multi-phase transformer having three or more phases.

  That is, in the columnar iron core 2, the cylindrical iron core 5, and the plate-like core 1 constituting the transformer, the cross-sectional area of the columnar iron core 2, the cross-sectional area of the cylindrical iron core 5, the cross-sectional area of the plate-like iron core 1, When the relative permeability, the relative permeability of the cylindrical core 5 and the relative permeability of the plate core 1 are in a specific relationship, the flow of magnetic flux in the transformer is remarkably smoothed, and the efficiency of the transformer of the present invention Improved characteristics.

First, the cross-sectional areas of the columnar core 2, the cylindrical core 5, and the plate-shaped core 1 will be described.
The cross-sectional areas of the columnar iron core 2 and the cylindrical iron core 5 are the areas in a cross section perpendicular to the axial direction of the transformer. In the present specification, basically, the columnar core 2 and the cylindrical core 5 are described as having no change in the cross-sectional area in the axial direction. However, when the cross-sectional area changes along the axial direction, The average value is the cross-sectional area.
The plate-like iron core 1 has a minimum cross-sectional area that passes through the “center of gravity of the shape of the plate-like iron core viewed from the axial direction of the transformer” and is parallel to the axial direction of the transformer. Here, the “minimum cross-sectional area” is because the magnetic flux density is maximum in this cross-section, and the influence on the efficiency of the transformer is increased in relation to the relative magnetic permeability defined in the present invention.

Next, subscripts for distinguishing the cross-sectional area S and relative permeability μ of each iron core will be described. The symbol S representing the cross-sectional area and the suffix 0 of μ representing the relative magnetic permeability indicate the cross-sectional area and the relative magnetic permeability of the columnar iron core 2. In addition, in the transformer having one or more cylindrical iron cores 5, one or more subscripts are numbered in order from the cylindrical iron core 3 on the side close to the columnar iron core 2 toward the outside. The relative permeability is shown separately. The subscript “plate” indicates the cross-sectional area and relative magnetic permeability of the plate-like iron core 1.
For example, the transformer of FIG. 3 has a structure having three cylindrical iron cores 5, the columnar iron core 2 has a cross-sectional area S 0 and a relative magnetic permeability μ 0, and the cylindrical iron core 5 has a cross-sectional area S 1, S 2, S 3, and Relative magnetic permeability μ1, μ2, and μ3 are defined.

According to the present invention, for each iron core constituting the transformer, the cross-sectional area and relative permeability of each iron core defined as described above satisfy the formula (1), so that the efficiency of the transformer can be improved. It is.

ただし、式（１）における添字ｋは、１以上の自然数であり、柱状鉄心の最も近くに配置された筒状鉄心を１とし、柱状鉄心から離れるに従い１づつ増加した数とする。

However, the subscript k in the formula (1) is a natural number of 1 or more, and the cylindrical core disposed closest to the columnar core is set to 1, and the number increases by 1 as the distance from the columnar core increases.

  It should be noted that when there are a plurality of cylindrical iron cores 5 in equation (1), it is not necessary to establish equation (1) for all the cylindrical iron cores 5 (all k). This is because the invention effect can be obtained even if any one of the cylindrical iron cores 5 is satisfied. Of course, a larger number of cylindrical iron cores 5 satisfying the formula (1) is preferable as an invention effect, and it is needless to say that the formula (1) is preferably satisfied for all the cylindrical cores 5 (all k). .

Further, in the present invention, two plate-like iron cores preferably have the same shape and the same relative magnetic permeability, but the present invention is not limited to this condition. In the present invention, two plate-like iron cores can exhibit more excellent efficiency by satisfying the following conditions.
When the cross-sectional areas of the two plate-shaped iron cores are Splate1 and Splate2, respectively, and the corresponding relative magnetic permeability are μplate1 and μplate2, respectively,

Or

Satisfying improves transformer efficiency,
further,

Satisfying is a highly preferred form.

  When the values of the formulas (1) to (3) are less than 0.80, the magnetic resistance of the entire transformer increases, and the characteristics such as the efficiency of the transformer of the present invention decrease. Determine. If the values of the formulas (1) to (3) exceed 1.20, the weight of the plate-like iron core of the transformer increases and the cost increases. More preferably, formulas (1) to (3) show characteristics such as better transformer efficiency in the range of 0.90 to 1.10.

  More preferably, the value of the formula (4) is 0.80 or more. Thereby, the magnetic resistance of the whole transformer is lowered, and the characteristics such as the efficiency of the transformer of the present invention are improved. Further, the value of the formula (4) is preferably 1.20 or less. Thereby, the weight of the plate-shaped iron core of the transformer is reduced, and the cost is reduced. More preferably, the formula (4) shows better characteristics such as the efficiency of the transformer when it is 0.90 or more and 1.10 or less.

  Although not specified as an invention, in a transformer having n cylindrical cores 5, the values of formulas (1) to (4) may be 1 in all cores including the plate-shaped core 1. Best form. That is, in this case, the formula (A) is established.

  μ0 × S0 = μ1 × S1 = ... = μn × Sn = μplate1 × Splate1 = μplate2 × Splate2 Expression (A)

Next, a method for determining the relative permeability of the columnar iron core 2, the cylindrical iron core 5, and the plate-like iron core 1 will be described.
In the present invention, the steel material used for each iron core is magnetized in a specific direction in a Helmholtz coil in consideration of the magnetization direction when used as the iron core, and the relative permeability is obtained.
For the columnar iron core 2 and the cylindrical iron core 5, the direction of the transformer axis is the magnetization direction. Therefore, the steel material is arranged so that the steel material is magnetized in this direction in the Helmholtz coil, and the relative permeability is obtained.

In the measurement, the size of the Helmholtz coil and the size of the steel material may be determined so that the magnetic field in the Helmholtz coil at the portion where the steel material is installed is uniform. Since this size is determined relatively, it is not necessary in principle to determine the absolute values of the Helmholtz coil size and the steel material to be measured.
Moreover, in the measurement of relative permeability, magnetic measurement is performed so as to reach the maximum operating magnetic flux density of each iron core calculated from the current flowing through the primary coil of the transformer, and the relative permeability of the steel material is obtained.

  Since the plate-like iron core 1 has a magnetization direction radial in the plate surface and a large magnetization component in the plate thickness direction, the relative permeability when the steel material is arranged in the Helmholtz coil so as to be magnetized in various directions is obtained. The average value is measured as the relative permeability of the plate-shaped iron core. Specifically, in the XYZ axis space, each of which is 90 °, when the XY plane coincides with the plate surface of the plate-shaped iron core and the Z direction coincides with the plate thickness direction of the plate-like iron core, Based on the relative magnetic permeability μx, μy, and μz obtained by magnetization in the direction, the Y-axis direction, and the Z-axis direction, the following formula (B) is defined as the relative magnetic permeability of the plate-like core.

In the measurement of the X-axis direction and the Y-axis direction, when using a steel material in which the rolling direction cannot be specified, an arbitrary direction is set to the 0 ° direction of the rotation coordinate around the Z-axis on the XY plane, and 22.5 An example is a method of measuring the relative magnetic permeability every °°.
That is, in this method, the relative permeability μ is measured in the XY plane at intervals of 22.5 ° clockwise starting from the 0 ° direction as a reference.
Measure the relative permeability of 22.5 °, 40 °, 67.5 °, 90 ° clockwise from the reference direction 0 °, and name them μ0, μ22.5, μ45, μ67.5, μ90. From the symmetry of the measurement direction, it is not necessary in principle to measure the relative permeability in the direction of 90 ° or more.
Based on these, the following formula (B1-22.5-1) is used, and the relative permeability μ of the plate-like iron core is determined by the formula (B2).

In order to improve the measurement accuracy, the relative permeability μ of one round is measured every 22.5 ° in the clockwise direction, and μ _XY is obtained as in the equation (B2-22.5-2), and the equation (B2) The determination of the relative permeability μ of the plate-like iron core can also be exemplified.

The method for measuring the magnetic permeability of the plate-shaped iron core 1 of the present invention is not limited to the above method. For example, in order to improve the measurement accuracy, it is also possible to obtain μ _XY by taking a measurement interval in the XY plane more finely and taking a weighted average thereof.
For example, when the relative permeability μ in the XY direction is measured clockwise every 10 °, the equation (B1-22.5) is changed to the following equation (B1-10).

Using this μ _XY , the relative permeability μ of the plate-like iron core is obtained by the equation (B2) together with μ _Z obtained by the above-described method.
Since there is no equivalent direction in this measurement method, μ _XY is different from equation (B1-22.5).
When setting the measurement interval, pay attention to the equivalent direction and formulate the weighted average equation, or mechanically measure the relative permeability at equal intervals over the entire circumference and set the average value to μ _XY Become.
In analog measurement, it is also possible to exemplify _obtaining μ _XY as an integral average value by continuously measuring. In the digital measurement, the average value obtained by measuring the entire circumference of the XY plane around the Z axis at every interval is the relative permeability μ _XY of the plate-like iron core. When digital measurement values are made continuous by numerical analysis, the integrated average value is μ _XY .
Μ _XY is obtained by the method exemplified above, and the relative permeability μ of the plate-like iron core is obtained by Equation (B2) together with μ _Z.
The method for measuring the relative permeability μ of the plate-like iron core 1 of the present invention is not limited to the method described above.

When the plate-like core 1 is formed by a steel plate produced by rolling or by laminating it, the relative permeability μ _L obtained by setting the magnetization direction as the rolling direction of the steel plate, and the magnetization direction from the rolling direction within the steel plate surface The relative permeability μ _T obtained as the 90 ° direction and the relative permeability μ _v obtained with the magnetization direction as the plate thickness direction are obtained by the following equation (C).

  What should be noted is the measurement of the relative permeability in the thickness direction of the steel sheet. A steel plate that is assumed to be used as a material in the present invention, such as an electromagnetic steel plate, generally has a thickness of about 0.1 to 0.5 mm. The magnetization characteristics in the thickness direction of such a thin plate can be measured by laminating them.

Next, details of the columnar iron core 2, the cylindrical iron core 5, and the plate-like iron core 1 constituting the transformer of this embodiment will be described.
The columnar core 2, the cylindrical core 5 and the plate-shaped core 1 according to the present embodiment are all made of steel. The reason why the core material is steel is that the relative permeability μ0, μk, or μplate of each core can be increased. The higher the relative permeability of each iron core, the more the copper loss of the excitation winding (primary coil and secondary coil) is reduced, which is advantageous for improving the efficiency of the transformer. Examples of the steel material include a steel bulk material, an electromagnetic steel plate, and an electric iron plate. Furthermore, as a magnetic steel plate, a directional magnetic steel plate or a non-oriented magnetic steel plate can be illustrated. In the following description, the electromagnetic steel plate and the electric iron plate may be collectively referred to as a steel plate. Further, the directional electrical steel sheet and the non-oriented electrical steel sheet may be collectively referred to as an electrical steel sheet.

  The columnar iron core 2, the cylindrical iron core 5 and the plate-like iron core 1 may be made of a steel bulk material. For example, a steel wire having a predetermined diameter may be cut into an appropriate length to form a columnar iron core. Moreover, you may divert a steel pipe with comparatively thickness to a cylindrical iron core. Further, the thick plate may be cut into a predetermined shape to form a plate-shaped iron core. The iron core obtained in this way. Both are steel bulk materials.

  Further, the columnar iron core 2, the cylindrical iron core 5, and the plate-like iron core 1 may be obtained by appropriately processing a steel plate as described below.

  The columnar iron core 2 and the cylindrical iron core 5 may be a laminated iron core obtained by cutting a steel plate into a plate shape and laminating the plate pieces. Specifically, it is possible to stack strip-shaped steel plates cut into various widths in a direction perpendicular to the axial direction of the transformer so that the in-plane direction of the steel plate coincides with the axial direction of the transformer. . In this case, it is easy to select a direction having a particularly high relative permeability in the plate surface of the steel sheet and align it with the magnetization direction of the iron core, which is advantageous in terms of transformer efficiency. However, it is necessary to prepare strip-shaped steel plates of various shapes, and productivity is inferior. Moreover, after laminating plate pieces having the same shape, they may be processed into a necessary iron core shape by cutting or the like.

  Alternatively, the steel plate may be stacked in the axial direction of the transformer with the plate thickness direction of the steel plate as the axial direction of the transformer. In this case, the planar view shape of the plate pieces constituting the laminated core is a cross-sectional shape orthogonal to the longitudinal direction of the columnar core 2. Therefore, for example, the columnar iron core 2 may be configured by stacking circular plate pieces. Moreover, in the case of the cylindrical iron core 5, what is necessary is just to comprise by laminating | stacking the board | plate piece shape | molded cyclically | annularly.

  The laminated iron core may be covered with an insulator. By covering the laminated iron core with an insulator, it is possible to prevent the insulation of the coil from being broken due to the contact between the laminated iron core and the coil. Examples of the insulator include resin and ceramics.

  The steel sheet constituting the laminated iron core is, for example, a non-oriented electrical steel sheet having a texture that contains a large number of crystal grains in which the orientation of the BCC iron coincides with <100> in the plate surface direction, enriched in the cube orientation. It is preferable to use it because the flow of magnetic flux in the direction perpendicular to the laminated plate surface is smoothed.

  Further, the columnar iron core 2 may be a laminated iron core obtained by laminating strip pieces obtained by forming a steel plate into a strip shape. The stacking direction of the strips when the columnar iron core 2 is a laminated iron core is a direction orthogonal to the direction in which the magnetic flux flows. In other words, the longitudinal direction of the strip pieces constituting the laminated core is made parallel to the axial direction of the columnar core 2.

  The laminated iron core may be covered with an insulator. By covering the laminated iron core with an insulator, it is possible to prevent the insulation of the coil from being broken due to the contact between the laminated iron core and the coil. Examples of the insulator include a hollow cylinder made of resin or ceramics. A laminated iron core may be stored in a hollow cylinder made of an insulator to form a columnar iron core.

  The steel plate constituting the laminated iron core may be, for example, a non-oriented electrical steel plate, a directional electrical steel plate, or an electric iron plate. In the case where the laminated iron core is composed of directional electromagnetic steel sheets, the easy magnetization axis direction of the directional electromagnetic steel sheets may be made to coincide with the axial direction of the columnar iron core.

Moreover, the columnar core 2 and the cylindrical core 5 may be wound cores formed by winding a steel plate. The direction of the winding axis of the steel plate is the direction that matches the flow direction of the magnetic flux. Specifically, it is good to set it as the height direction of the columnar iron core or cylindrical iron core at the time of assembling a transformer.
On the other hand, when the columnar core 2 is a wound core, a steel plate having an appropriate width and length may be wound into a cylindrical shape to form a wound core. Here, the higher the space factor of the steel sheet in the wound iron core, the better. However, when the columnar iron core 2 is used as the wound iron core, the center of the columnar iron core 2 has a smaller winding radius of the steel sheet, and is affected by the residual stress. The degree of deterioration of characteristics increases. Therefore, a cylindrical gap may be left in the center of the columnar iron core 2.
When the cylindrical core 5 is a wound core, a steel sheet having an appropriate width and length may be wound in an annular shape to form a wound core.

The steel plate constituting the wound core may be, for example, a non-oriented electrical steel plate, a directional electrical steel plate, or an electric iron plate.
When the columnar iron core 2 is a wound iron core, a directional electromagnetic steel sheet may be used. In this case, the easy axis direction of magnetization of the directional electromagnetic steel sheet may be matched with the winding axis direction of the wound iron core.
When the cylindrical iron core 5 is a wound iron core, the non-directional electromagnetic having a texture in which the cube orientation is enriched and has a large number of crystal grains in which <100> which is the easy magnetization axis of BCC iron coincides with the plate surface direction. A steel plate is preferably used. In this case, the flow of magnetic flux in the direction perpendicular to the wound plate surface is smooth, which is preferable.

  The wound core is not limited to one wound around a single steel plate, and a plurality of steel plates may be wound so as to be concentrically stacked to form a wound core. At that time, a known technique called step lap in which the butted portions are sequentially shifted from the center to the outside may be used.

  From the viewpoint of cost, when the columnar iron core 2 and the cylindrical iron core 5 are composed of wound cores, it is preferable to wind with a single steel plate cut in the width direction of the steel strip, but when the winding length is insufficient If necessary, the steel plates may be butted against each other at the lacking portion.

  The thickness of the electrical steel sheet according to the present embodiment is not particularly limited as long as it is appropriately adjusted, but is usually 0.004 mm or more and 0.65 mm or less, and 0.010 mm or more and 0.0. 50 mm or less is more preferable. From the viewpoint of the balance between magnetic properties and productivity, 0.015 mm or more and 0.35 mm or less is preferable.

In this embodiment, it is preferable that the magnetic properties in the axial direction of the columnar iron core 2 and the cylindrical iron core 5 are particularly excellent. Therefore, when a grain-oriented electrical steel sheet is used as a constituent material of the columnar iron core 2 and the cylindrical iron core 5, the axial direction of the columnar iron core 2 and the cylindrical iron core 5 is preferably matched with the rolling direction of the grain-oriented magnetic steel sheet.
Moreover, since a general non-oriented electrical steel sheet has excellent magnetic properties in the rolling direction, the axial direction of the columnar iron core 2 and the cylindrical iron core 5 is determined by the non-oriented electrical steel sheet as in the case of the directional electromagnetic steel sheet. It is good to match with the rolling direction. Non-oriented electrical steel sheet is subjected to hot-rolled sheet annealing, the grain size before cold rolling is increased, and the {110} <001> orientation called GOSS orientation in the recrystallized texture is enriched. It is preferable that it is a heat-resistant electrical steel sheet.

  Next, the plate-like iron core 1 is a plate-like member, and is connected to both axial ends of the columnar iron core 2 as shown in FIG. The plate-like iron core 1 is also connected to both axial ends of the cylindrical iron core. The plate-like iron core 1 may be a plate piece obtained by forming a steel plate into a predetermined shape, or may be a laminate of a plurality of plate pieces. In the plate-like core 1, the flow direction of the magnetic flux is the in-plane direction of the plate-like core, and the in-plane direction is radial so as to connect the columnar core 2 and the cylindrical core 5. It is good to be comprised with a steel plate.

  The joining method of each iron core in the connection part of the columnar iron core 2, the cylindrical iron core 5, and the plate-like iron core 1 is not particularly limited as long as the loss of magnetic flux can be minimized. For example, the joining method illustrated in the following (1) to (4) can be adopted.

(1) Join each iron core with an adhesive. At that time, the magnetic resistance is reduced as much as possible by an adhesive that makes the adhesive gap as thin as possible.
(2) When the columnar iron core is a laminated core obtained by laminating strip-shaped electromagnetic steel sheets, or when the columnar iron core is a wound iron core wound around a cylindrical steel sheet, projecting portions are formed at both axial ends of the columnar iron core. On the other hand, a recess is formed in the plate-shaped iron core, and these are fitted. Or a recessed part is formed in a cylindrical iron core, a convex part is formed in a plate-shaped iron core, and these are fitted. As a method of providing the concave portion in the plate-shaped iron core, a concave portion that can be fitted by cutting the plate-shaped iron core is provided, or a concave portion corresponding to the convex portion of the cylindrical core is provided in the plate-shaped iron core. A plate-shaped iron core having a concave portion is divided and punched by dividing a plate-shaped iron core having a gap corresponding to the convex portion of the cylindrical iron core, and the gap is laminated so as to fit into the convex portion of the cylindrical iron core. The number of stacked layers is determined according to the protrusion of the convex portion.
Thereby, a recessed part is formed in a plate-shaped iron core, and it is made to mutually fit with the convex part of a cylindrical iron core. However, since a residual stress is generated in the plate-shaped iron core by cutting the plate-shaped iron core and becomes a magnetic resistance, it is necessary to select a machining method that does not generate the residual stress as much as possible.
(3) When the columnar iron core covers the outer periphery of the laminated core with an insulating material, the insulating material is provided with a portion that protrudes from the longitudinal direction of the iron core, the plate-like iron core is cut, and a concave portion that can be fitted is provided. When a plate-shaped iron core is laminated, a concave portion corresponding to the convex portion of the cylindrical iron core is provided and fitted with a convex portion formed of an insulating material. A plate-shaped iron core having a concave portion is divided and punched by dividing a plate-shaped iron core having a gap corresponding to the convex portion of the cylindrical iron core, and the gap is laminated so as to fit into the convex portion of the cylindrical iron core. The number of stacked layers is determined according to the protrusion of the convex portion.
Thus, a concave portion is formed in the plate-shaped iron core, and the columnar iron core is covered with an insulating material that is convex.
However, since a residual stress is generated in the plate-shaped iron core by cutting the plate-shaped iron core and becomes a magnetic resistance, it is necessary to select a machining method that does not generate the residual stress as much as possible.
(4) A cylindrical iron core and a plate iron core are welded by a method such as spot welding by a method capable of reducing thermal strain as much as possible.

  By joining each iron core as described above, a magnetic path composed of the columnar iron core 2, the cylindrical iron core 5, and the plate-like iron core 1 is formed. The columnar iron core 2, the cylindrical iron core 5 and the plate-like iron core 1 are preferably made of a steel material having magnetic characteristics satisfying the above expression (1), and a steel material having magnetic characteristics satisfying the above expression (2). More preferably, it consists of. In particular, the steel materials constituting the columnar iron core 2, the cylindrical iron core 5, and the plate-like iron core 1 are preferably electromagnetic steel sheets having the component composition described below. This is to make the magnetic characteristics of each iron core preferable. Specific magnetic properties are relative permeability, iron loss, and magnetic flux density. In particular, considering the direction of the magnetic flux of each iron core, in order to control the crystal orientation of the steel material so that the easy axis of magnetization is aligned in that direction, a structure in which electromagnetic steel sheets are laminated is preferable. The magnetic steel sheet is controlled in crystal orientation so that the easy axis of magnetization is aligned in a specific direction in the plate surface, and it is preferable for the characteristics of the cylindrical transformer to align this direction with the direction of the magnetic flux of each iron core. The electromagnetic steel sheet need not be special and can be made of a known non-oriented electrical steel sheet or directional electrical steel sheet.

  The non-oriented electrical steel sheet that can be suitably applied to each iron core of the present embodiment is, for example, mass%, 0.1 ≦ Si ≦ 3.5, 0.1 ≦ Mn ≦ 1.5, Al ≦ 2.5. C ≦ 0.003, N ≦ 0.003, S ≦ 0.003, the balance being Fe and other inevitable impurities.

  The non-oriented electrical steel sheet contains at least Si (silicon) and Mn (manganese), and may further contain Al (aluminum), and C (carbon), N, as long as the effects of the present invention are not impaired. (Nitrogen), S (sulfur) and other inevitable impurities may be contained, and the balance is composed of Fe (iron).

(0.1 ≦ Si ≦ 3.5)
The non-oriented electrical steel sheet has a Si content of 0.1% to 3.5%. Since Si has an action of increasing electric resistance, it contributes to iron loss reduction. The non-oriented electrical steel sheet has a Si content of 0.1% or more, preferably 0.5% or more, and more preferably 1.0% or more, from the viewpoint of reducing iron loss. In order to further improve the iron loss, 1.9% or more is more preferable. On the other hand, the non-oriented electrical steel sheet according to the present embodiment is excellent in magnetic properties, has good rolling workability, and suppresses an increase in the annealing temperature of the finish, so that the Si content is 3.5% or less. 3.2% or less is preferable, and 2.7% or less is more preferable. In order to further improve the rolling workability, 2.4% or less is more preferable.

(0.1 ≦ Mn ≦ 1.5)
The non-oriented electrical steel sheet has a Mn content of 0.1% to 1.5%.
Mn is made 0.1% or more from the viewpoint of increasing the electric resistance and reducing the iron loss, and if it exceeds 1.5%, the recrystallized structure is refined and the iron loss is increased to 1.5% or less. Stipulated in
More preferably, the range for appropriately reducing the iron loss is 0.5% or more and 1.0% or less.

(Al ≦ 2.5)
The non-oriented electrical steel sheet may contain Al. When the non-oriented electrical steel sheet contains Al, it is preferably 0.1% or more and 2.5% or less, more preferably 0.3% or more and 2.4% or less from the viewpoint of reducing iron loss. More preferably, it is 0.9% or more and more preferably 2.3.

(Inevitable impurities)
The non-oriented electrical steel sheet may contain various elements (unavoidable impurities) that are inevitably mixed within a range that does not impair the effects of the present invention.
Examples of such elements include C, N, and S, as well as Ti (titanium), Nb (niobium), As (arsenic), and Zr (zirconium).
The content ratio of C is 0.003% or less, more preferably 0.002% or less, from the viewpoint of excellent magnetic properties. Further, in order to obtain excellent magnetic properties, 0.001% or less is preferable.
The content ratio of N is 0.003% or less, more preferably 0.002% or less, from the viewpoint of excellent magnetic properties. Further, in order to obtain excellent magnetic properties, 0.001% or less is more preferable.
The S content is 0.003% or less, more preferably 0.002% or less, from the viewpoint of excellent magnetic properties. Further, in order to obtain excellent magnetic properties, 0.001% or less is more preferable.
The Ti content is preferably 0.004% or less, more preferably 0.003% or less, from the viewpoint of excellent magnetic properties. Further, in order to obtain excellent magnetic properties, 0.002% or less is more preferable, and 0.001% or less is particularly preferable.
The Nb content is 0.003% or less, more preferably 0.002% or less, from the viewpoint of excellent magnetic properties. Further, in order to obtain excellent magnetic properties, 0.001% or less is preferable.
From the point which is excellent in a magnetic characteristic, the content rate of As is 0.003% or less, Furthermore, 0.002% or less is more preferable. Further, in order to obtain excellent magnetic properties, 0.001% or less is preferable.
The content ratio of Zr is 0.003% or less, more preferably 0.002% or less, from the viewpoint of excellent magnetic properties. Further, in order to obtain excellent magnetic properties, 0.001% or less is preferable.
The content ratio of P is 0.25% or less, more preferably 0.15% or less, from the viewpoint of excellent magnetic properties. Further, in order to obtain excellent magnetic properties, 0.10% or less is preferable.
In addition, the content ratio of all inevitable impurities is preferably 0.1% or less, and more preferably 0.05% or less, from the viewpoint of excellent magnetic properties.

The content ratio of each element in the non-oriented electrical steel sheet can be measured by known methods under the following method according to the type of element.
Si, Mn, Al, Ti, Nb, and Zr can be measured by inductively coupled plasma mass spectrometry (ICP-MS method).
As can be measured by flameless atomic absorption.
C and S can be measured by a combustion infrared absorption method.
Further, N can be measured by a heat melting-heat conduction method.

Specifically, first, a non-oriented electrical steel sheet to be measured is prepared. When the non-oriented electrical steel sheet includes an insulating coating or other layers, the coating or the like is removed in advance by a known method.
A part of the non-oriented electrical steel sheet is cut into a face shape and weighed, and this is used as a measurement sample. The measurement sample is processed as follows according to the measurement method. In the combustion infrared absorption method and the heat-melting-heat conduction method, the facet-shaped measurement sample can be used as it is.

(A) Inductively coupled plasma mass spectrometry (ICP-MS method)
The measurement sample is dissolved in an acid to obtain an acid solution (may be heated if necessary). The residue is recovered by filter paper and separately melted in alkali or the like, and the melt is extracted with an acid to form a solution. An ICP-MS measurement solution can be obtained by mixing the solution and the acid solution and diluting the solution as necessary.

(B) Flameless atomic absorption method (AA method)
The measurement sample is dissolved in an acid to obtain an acid solution (may be heated if necessary). By diluting the obtained acid solution as needed, it can be set as the solution for AA method measurement.

  Since the transformer of this embodiment only creates and assembles two plate-shaped iron cores 1, columnar iron cores 2, primary coils 3, secondary coils 4, and cylindrical iron cores 5, the transformer manufacturing process is as follows. Simple and cost saving. Moreover, when manufacturing an iron core, it is not necessary to provide a groove or a recess for inserting a coil as in various conventional transformers, and the structure becomes simple.

  A single-phase transformer has been described as an example of the transformer of this embodiment, but the transformer of the present invention is not limited to a single-phase transformer and may be applied to a three-phase transformer. Moreover, even when applied to multi-phase transformers such as 6-phase, 12-phase, 24-phase, 36-phase, and 48-phase that are used to reduce the harmonics contained in the power source, which has become a problem with the spread of inverters. Good. Furthermore, you may apply to a transformer with a phase-shift winding. A transformer with a transfer winding is a transformer having a phase shift angle as a staggered connection. Furthermore, the transformer of the present invention may be of a type cooled by a technique such as water cooling, oil cooling, or air cooling.

  When the transformer is a multiphase transformer, a primary coil and a secondary coil are arranged between the cylindrical iron cores arranged concentrically. The arrangement may be arranged up and down in the axial direction of the cylindrical iron core, but in order to further utilize the effects of the present invention, it is preferable to arrange the primary coil and the secondary coil in a concentric circle shape, and three-phase. In the case of a three-winding transformer, it is preferable to arrange the primary coil, the secondary coil, and the tertiary coil concentrically.

  Moreover, the transformer which is the object of the present invention is a transformer used for various applications such as a general transformer, a reactor, a choke coil, and a current sensor as well as a small transformer used in an electric device. Also good.

  Moreover, the primary coil and the secondary coil of the transformer in the present embodiment are both wound in a circular shape, and as to which of the primary coil and the secondary coil is to be arranged inside, the use and It may be determined according to the characteristics of the transformer. Further, not only the primary coil and the secondary coil are arranged concentrically, but the primary coil 3 and the secondary coil 4 may be arranged side by side along the axial direction of the columnar core 2 as shown in FIG.

  In addition, it is preferable from the viewpoint of processing that the lead wires to the outside of the primary coil 3 and the secondary coil 4 are provided with a recess in the cylindrical core 5, but a groove or the like is formed in the plate-like core 1. You may pull out a conducting wire. When forming the lead wire drawing groove in the plate-shaped iron core 1, it is preferable to punch a horseshoe-shaped ring having a groove portion at the time of punching, and stack the cuts of the ring to form the lead wire drawing portion. Thereby, it is not influenced by the residual stress of the cylindrical iron core 5 by cutting after lamination | stacking is complete | finished, and the characteristic of a transformer can be improved more.

  Moreover, it may replace with the primary coil and secondary coil which comprise the transformer of this embodiment, and may arrange | position a single coil in the gap | interval of a columnar iron core and a cylindrical iron core. In this case, it can function as a reactor. Even when the reactor is formed, the effects of the present invention can be sufficiently obtained.

  Below, the example of a transformer structure in the case of applying this invention to a three-phase transformer is demonstrated.

  The three-phase transformer shown in FIG. 3 includes a columnar iron core 2, cylindrical iron cores 5A, 5B, and 5C that are arranged concentrically around the columnar iron core 2 and have different diameters, and the columnar iron core 2 and the cylindrical iron core 5A. ˜5C sandwiched from above and below, and the primary coil 3 and the secondary coil arranged between the columnar core 2 and the cylindrical core 5A, or between the cylindrical cores 5A to 5C. 4.

  The cylindrical iron cores 5A to 5C provided in the three-phase transformer shown in FIG. 3 include a first cylindrical iron core 5A closest to the columnar iron core 2 and a second outer core on the outer side of the first cylindrical iron core 5A. There are a cylindrical iron core 5B and a third cylindrical iron core 5C on the outer peripheral side of the second cylindrical iron core 5B.

  Further, the primary coil 3 and the secondary coil 4 provided in the three-phase transformer shown in FIG. 3 include a U-phase primary coil 3a and a U-phase arranged between the columnar iron core 2 and the first cylindrical iron core 5A. Secondary coil 4a, V-phase primary coil 3b and V-phase secondary coil 4b arranged between first cylindrical iron core 5A and second cylindrical iron core 5B, second cylindrical iron core 5B and third cylinder There is a W-phase primary coil 3c and a W-phase secondary coil 4c arranged between the iron core 5C. In each phase coil, the secondary coil 4 is arranged on the outer peripheral side of the primary coil 3, but the present invention is not limited to this, and the secondary coil 4 may be inside the primary coil 3.

  Although a three-phase transformer is shown in FIG. 3, a multi-phase transformer may be used. In the case of a multi-phase transformer of three or more phases, assuming that the number of phases is n, the structure of the transformer is that two plate-like cores are arranged at both ends in the axial direction of the columnar iron core, and n diameters are different concentrically. A cylindrical iron core is arranged, and n sets of primary coils and secondary coils are arranged as a set in n gaps.

Further, the transformer of the present invention is not limited to the order of the primary coil and the secondary coil of each phase in any one of the annular gaps that exist concentrically. In addition, the arrangement of the primary coil and the secondary coil is preferably concentric because it facilitates the flow of magnetic flux, but may be arranged in the direction of the cylindrical axis.
In the case of a three-phase three-winding transformer, the third coil for reducing harmonics may be an annular coil having the same shape when viewed from the axial direction of the primary coil, secondary coil, and transformer. Take an example. Along with the primary coil and the secondary coil, this is disposed so as to overlap in the axial direction in the central iron core and the cylindrical iron core or in the gap between the cylindrical iron cores.
If the shapes of the primary coil, the secondary coil, and the third coil are annular, the inner diameter and the outer diameter are not necessarily the same.

  As explained above, according to the transformer of this embodiment, the flow of magnetic flux in the cylindrical iron core is made uniform by configuring each iron core so that the above formula (1) and further formula (2) are satisfied. , The magnetic resistance can be reduced, and the efficiency of the transformer can be improved.

  Hereinafter, the present invention will be specifically described with reference to examples. These descriptions do not limit the present invention.

[Example 1]
A slab containing Si: 0.3%, Mn: 0.2%, Al: 0.2% was hot-rolled at a heating temperature of 1100 ° C. to obtain a hot-rolled steel sheet having a thickness of 2.5 mm. Next, the hot-rolled sheet was pickled and then cold-rolled to obtain a cold-rolled steel sheet having a thickness of 0.5 mm. Next, finish annealing was performed on the cold-rolled steel sheet at 750 ° C. for 5 to 45 seconds to obtain a non-oriented electrical steel sheet. By adjusting the relative permeability of the material of the non-oriented electrical steel sheet by changing the finish annealing time, the ratio of the columnar iron core, cylindrical iron core, and plate iron core used for the transformer when assembled using this The permeability was changed.

Using this electromagnetic steel sheet as a raw material, the following columnar iron core, cylindrical iron core, and plate-shaped iron core are created, and these cores are combined to produce a single-phase compound winding transformer having the structure shown in FIGS. Produced.
The columnar iron core was formed by laminating strip-shaped steel plates having a vertical size of 40 cm which is the height of the columnar iron core and cut in various widths so that the vertical cross section in the axial direction is substantially circular. The cross-sectional area S was changed by appropriately adjusting the width of the strip-shaped steel plates to be laminated and the number of laminated sheets. Moreover, the relative magnetic permeability in the axial direction of the iron core was changed by changing the cutting direction of the strip within the steel plate surface. After the lamination, an insulator was wound around the laminated iron core so as not to cause a dielectric breakdown with the coil.

  The cylindrical iron core was formed by winding a strip-shaped steel plate cut to an appropriate length into a hollow cylindrical shape with a height of 40 cm, which is the height of the cylindrical core for manufacturing the vertical size. The cross-sectional area S was changed by changing the inner diameter of the cylinder by fixing the outer diameter of the cylinder to 30 cm and changing the number of windings. The relative permeability in the axial direction of the iron core was changed by changing the cutting direction of the strip within the steel plate surface.

The plate-like iron core was formed by punching out a disc having a diameter of 30 cm, which is the outer diameter of the cylindrical iron core, and laminating it. The cross-sectional area S was changed by changing the number of stacked layers. Thereafter, the efficiency of these transformers was measured.
The results are shown in Table 1.

As can be seen from Table 1, when the value of μ1 × S1 / μ0 × S0 within the range of the present invention is 0.80 or more and 1.20 or less, the efficiency of the cylindrical transformer of the present invention is 95%. The above excellent values are shown.
In particular, in the range of 0.90 to 1.10, a further excellent value of 97% or more is shown, and it can be seen that the range is more preferable.
On the other hand, when the value of μ1 × S1 / μ0 × S0 is less than 0.80 or more than 1.20, the efficiency is a low value of 90% or less.

[Example 2]
A slab containing Si: 2.0%, Mn: 0.5%, Al: 0.5% was hot-rolled at a heating temperature of 1150 ° C. to obtain a hot-rolled steel sheet having a thickness of 2.5 mm. Subsequently, the hot-rolled steel sheet was annealed at 900 ° C. for 60 seconds. Thereafter, the hot-rolled steel sheet was pickled and further cold-rolled to obtain a cold-rolled steel sheet having a thickness of 0.5 mm. Next, finish annealing was performed on the cold-rolled steel sheet at 900 ° C. for 5 to 60 seconds to obtain a non-oriented electrical steel sheet.
By adjusting the relative permeability of the material of the non-oriented electrical steel sheet by changing the finish annealing time, the ratio of the columnar iron core, cylindrical iron core, and plate iron core used for the transformer when assembled using this The permeability was changed.

  Using this electromagnetic steel sheet as a raw material, the following columnar iron core, cylindrical iron core, and plate iron core were prepared, and these three cores were combined to produce a three-phase three-winding transformer having the structure shown in FIG.

  The columnar iron core was formed by laminating strip-shaped steel plates having a vertical size of 40 cm which is the height of the columnar iron core and cut in various widths so that the vertical cross section in the axial direction is substantially circular. The cross-sectional area S was changed by appropriately adjusting the width of the strip-shaped steel plates to be laminated and the number of laminated sheets. Moreover, the relative magnetic permeability in the axial direction of the iron core was changed by changing the cutting direction of the strip within the steel plate surface. After the lamination, an insulator was wound around the laminated iron core so as not to cause a dielectric breakdown with the coil.

  The cylindrical iron core was formed by winding a strip-shaped steel plate cut to an appropriate length into a hollow cylindrical shape with a height of 40 cm, which is the height of the cylindrical core for manufacturing the vertical size. The outer diameters of the three cylinders were fixed at 30 cm, 50 cm, and 70 cm, and the sectional area S was changed by changing the inner diameter of the cylinders by changing the number of windings. The relative permeability in the axial direction of the iron core was changed by changing the cutting direction of the strip within the steel plate surface.

The plate-like iron core was formed by punching out a circular plate having a diameter of 70 cm, which is the outer diameter of the largest cylindrical iron core, and laminating the same. The cross-sectional area S was changed by changing the number of stacked layers.
The efficiency of these transformers was measured in the same manner as in Example 1.
The results are shown in Table 2.

As can be seen from Table 2, when the value of μ1 × S1 / μ0 × S0 within the range of the example of the present invention is 0.80 or more and 1.20 or less, the efficiency of the cylindrical transformer of the present invention is 95%. The above excellent values are shown.
In particular, in the range of 0.90 to 1.10, a further excellent value of 97% or more is shown, and it can be seen that the range is more preferable.
On the other hand, when the value of μ1 × S1 / μ0 × S0 is less than 0.80 or more than 1.20, the efficiency is a low value of 90% or less.

  In addition to the embodiments described above, the relative permeability can be adjusted by the following method. Note that the method of adjusting the relative permeability μ of the present invention is not limited to these examples.

  The relative permeability μ of the steel sheet can be adjusted by adjusting the process conditions or components, and the relative permeability μ of the iron core can be adjusted using these steel sheets. Process conditions specifically include hot rolled sheet manufacturing by hot rolling or thin sheet casting, slab reheating temperature, hot rolling finishing temperature and hot rolling coiling temperature adjustment, presence / absence of hot rolling sheet annealing, cold rolling Adjustment of the rate, implementation of different peripheral speed cold rolling, temperature increase rate of finish annealing, adjustment of the holding temperature, the annealing time at the holding temperature, and the temperature decreasing rate, and the like. With these means, it is possible to adjust the relative permeability of the steel sheet and to adjust the relative permeability μ of each iron core assembled with the steel sheet.

  Further, by incorporating steel plates having at least two different relative magnetic permeability into one iron core, it is possible to adjust the relative magnetic permeability μ and the anisotropy of the iron core.

  In terms of components, the relative magnetic permeability μ can be changed by adjusting the contents of C, N, and S, which are Si, Al, and Mn contents and trace components. The relative permeability μ can be further adjusted by combining the component adjustment and the process conditions.

  With these methods, the relative magnetic permeability μ of the steel sheet can be adjusted within the range of 4000 to 6400 including the exemplary range in the components of Example 1. In addition, the component of Example 2 can adjust the relative permeability between 5500 and 12000 including the exemplary range.

  DESCRIPTION OF SYMBOLS 1 ... Plate-shaped iron core, 2 ... Columnar iron core, 2a, 2b ... Axial direction edge part of columnar iron core 3, 3a, 3b, 3c ... Primary coil 4, 4a, 4b, 4c ... Secondary coil 5, 5A, 5B, 5C: cylindrical iron core, 5a, 5b: axial end of the cylindrical iron core

Claims (4)

One columnar core, and one or more cylindrical cores arranged around the columnar core;
Two plate-like cores connected to the axial ends of the columnar core and connected to the axial ends of the cylindrical core;
A cylindrical transformer provided with a primary coil and a secondary coil disposed between the columnar iron core and the cylindrical iron core;
The relative permeability of the columnar iron core is μ0,
The cross-sectional area of the columnar core is S0,
Μk, the relative permeability of the k-th cylindrical iron core,
The cross-sectional area of the k-th cylindrical iron core is Sk,
Then, the following formula (1) is established for at least one cylindrical iron core.

However, the subscript k in the formula (1) is a natural number of 1 or more, and the cylindrical core disposed closest to the columnar core is set to 1, and the number increases by 1 as the distance from the columnar core increases. The transformer of claim 1, further comprising:
One plate iron core has a relative magnetic permeability μplate1, its cross-sectional area perpendicular to the axial direction is Splate1,
When the relative permeability of the other plate-shaped core is μplate2 and the cross-sectional area perpendicular to the axial direction is Splate2,
The following formula (2) and the following formula (3) are satisfied, The transformer according to claim 1 characterized by things.

At least one of the columnar iron core, the cylindrical iron core, and the plate iron core is in mass%,
0.1 ≦ Si ≦ 3.5,
0.1 ≦ Mn ≦ 1.5,
Al ≦ 2.5,
C ≦ 0.003,
N ≦ 0.003,
S ≦ 0.003,
The transformer according to claim 1 or 2, wherein the balance is an iron core made of a steel material made of Fe and inevitable impurities.   The transformer according to claim 3, wherein the steel material is a single electromagnetic steel plate or a laminate of two or more electromagnetic steel plates.

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