JPS58175807A - Magnetic core for transformer - Google Patents

Abstract

PURPOSE:To obtain the magnetic core, core loss thereof is small, by using a high silicon steel band in which <100> orientation is orientated in the thickness direction and <011> orientation is orientated in the longitudinal direction. CONSTITUTION:A hardener of Fe93.4Si6.6 (weight ratio is used as a composition ratio) is prepared, the hardener is entered into a nozzle 2, high-frequency currents are flowed through the coil 1, and the hardener is changed into molten metal 6 through induction heating. The molten metal 6 is ejected onto the rotary surface of a revolving body 3 made of iron from the nozzle 2, and quenched and solidified, thus obtaining the high silicon steel band 5. The steel band 5 is punched inclined at 45 deg. in the longitudinal direction, and the magnetic core for the transformer is formed by alternately laminating magnetic core thin-pieces acquired to insulating films.

Description

[Detailed description of the invention] The present invention relates to a magnetic core for a transformer.

Conventionally, magnetic cores for magnetic circuits such as transformers have three
Weight percent silicon steel sheets have been used, but their low electrical resistivity results in large power losses, and further attempts have been made to improve them. As improved materials, there are unidirectional silicon steel plates and bidirectional silicon steel plates. When configuring a UI type transformer core as shown in Figure 1 (m) using a unidirectional silicon steel plate, the working type core is parallel to the rolling direction, and both arms of the U type magnetic core are parallel to the rolling direction. Since it is punched out, the easy magnetization direction can only be used on three of the four sides.

As a result, iron loss increases. In addition, if the transformer core is made of bidirectional silicon steel plates as shown in Figure 1(B), all four sides can be used in all directions of easy magnetization.
Iron loss is smaller than the magnetic core in the same figure (m). However, due to the bending of the magnetic flux at the corners, not all of the magnetic paths are in the direction of easy magnetization, so further improvements are desired.

When silicon steel plate contains 5 to 8% by weight of silicon,
Because its resistivity is more than twice the electrical resistivity of conventional 3% silicon steel sheets and its saturation magnetostriction constant is small, this material is extremely suitable for use in magnetic cores for electrical circuits. This high silicon steel FjI′i containing 6 to 8% by weight of silicon
Since cold NL rolling is extremely difficult, it is difficult to reduce the thickness of the sheet, and it has not been put to practical use as a magnetic core.

Recently, research has been conducted on producing high-silicon steel ribbons using liquid ultra-quenching technology. According to the results, it was found that even in silicon-iron alloys with a high silicon content, thin ribbons with extremely high toughness can be easily obtained by using the ultra-quenching method. In this ribbon, heat flow is mainly generated in the thickness direction of the ribbon during the solidification process, so preferential growth of crystals occurs in the thickness direction. In other words, X-ray diffraction revealed that the preferred orientation is <100> and that there is no orientation within the plane of the ribbon. Therefore, this ribbon can be laminated by toroidal winding or punching. When used in a magnetic core for a transformer, the flow direction of magnetic flux is not the direction of easy magnetization, and there is no characteristic in terms of iron loss compared to conventional oriented silicon steel sheets. As a result of various studies on such ultra-quenched high-silicon steel strips, the inventors found that they can be made into thin strips by heat treatment at 900 to 1200°C in a lower vacuum of 8 x 10' torr or in an inert gas atmosphere. It has been found that <O'11> orientation is oriented as L in the longitudinal direction of the ribbon within the plane.

The texture was (10o)[011]. As shown in FIG. 2, such a thin strip is punched out at an angle of 45 degrees with respect to the longitudinal direction of the thin strip 9. When the obtained thin magnetic core pieces are stacked, the flow direction of the magnetic flux is changed. All are in the easy axis direction of magnetization. Since this magnetic core contains a large amount of silicon, it has a high resistivity, making it possible to obtain a transformer core with unprecedentedly low iron loss. Furthermore, when the entire transformer was constructed using the magnetic core according to the present invention and the noise characteristics were measured, it was found that the noise characteristics were extremely low. This is due to its high orientation, and enables the realization of a magnetic core for transformers with low noise and low loss.

Next, examples of the present invention will be described.

Example 1 A mother alloy of F2O3,4Si6.6 (composition ratio is weight percentage) was prepared, and as shown in FIG.
It was induction heated to ℃ to obtain molten metal e. A force of 0.3~0,'K//cAOif is applied to the molten metal 6 using argon gas, and the molten metal is jetted from the nozzle 2 onto the rotating surface of the cylindrical iron rotating body 3 rotating at a circumferential speed of 22 m/sec to rapidly cool it. , a high-silicon steel strip 6'i was obtained by solidification. The ribbon thus obtained had a thickness of 60 μm with 16 scratches.

This thin strip is punched out at an angle of 46° in the longitudinal direction as shown in FIG. 2, and the obtained magnetic core thin pieces 7 are laminated alternately with insulating films 8 as shown in FIG. 4 to form a magnetic core for a transformer. did.

For comparison, a wound core transformer was fabricated using a conventional highly oriented silicon steel plate.

The core loss at 5oHz of the magnetic core obtained in this way is calculated as
As shown in the figure. As is clear from this, according to the method of the present invention, iron loss is significantly reduced.

And the noise is also reduced by the novelty of the conventional wound core transformer mentioned above.
1 iodB, the transformer of the present invention has a power of -41 iB.
Met.

Example 2 High silicon steel strip Fe with Q1QIEI thickness. . −xSix(x
24.6, 5.3, e, s) and an insulating film were alternately laminated as in Example 1.

Figure 6 shows the iron loss (1,sT, 5OHz)k.

In the figure, point M is o, 3ysJ highly oriented silicon steel plate magnetic core, curve B is Fe, oo, Si! A magnetic core made of a (100) non-oriented high-silicon steel strip and a curve C each represent the iron loss characteristics of the magnetic core of the present invention. It can be seen from this that the core loss of the magnetic core of the present invention is small.

As described above, according to the present invention, it is possible to provide a transformer core with low iron loss, low noise, and excellent magnetic properties.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are diagrams showing the square closed magnetic circuit laminated magnetic core punched from grain-oriented silicon steel sheets, Figure 2 is a diagram showing the method for forming the magnetic core of the present invention, and Figure 3 is a diagram showing the method of forming the magnetic core of the present invention. A diagram illustrating the method, FIG. 4, is an embodiment of the present invention. Perspective view of the magnetic core,
Figure 6 is a diagram comparing the iron loss of the magnetic core of the present invention and a grain-oriented silicon steel plate. Figure 6 is a diagram comparing the iron loss of the magnetic core of the present invention and a comparative example. be. 7...Magnetic core thin piece, 8...Insulating film, 9...
...(1oO) [o11] High silicon steel strip with structure, 1o
...Punching core. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Fig. 4 Fig. 5 Ishinami Eigaureki (J) Tomi 6 Fig. Fe tca-y 3bX

Claims (1)

[Claims] Contains 5.0 to 8.0% by weight of silicon, and in the thickness direction (
100) A transformer comprising a high-silicon steel strip whose orientation is substantially oriented and whose orientation is substantially oriented in the longitudinal direction, and characterized in that the direction in which magnetic flux flows is the direction of easy magnetization. core.