JPS5837681B2 - inner iron transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a core type transformer in which windings are wound around the legs of an iron core formed by laminating steel strips or steel plates.

When designing a transformer, consideration must be given to minimizing the amount of iron and copper as much as possible.

In conventional core type transformers, the shape of the cross section of the leg of the core is generally aligned with the X axis extending in the stacking direction, as shown in Figure 1.
The core was formed symmetrically with respect to the Y axis, which is perpendicular to the Not only is it difficult to reduce the electrical loss of the transformer, but there is also a limit to how much the cost of the transformer can be reduced.

An object of the present invention is to provide an economical inner iron type transformer that uses a core having legs with an asymmetrical cross-sectional shape so that the amount of iron and copper can be reduced compared to conventional ones. It is in.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The core type transformer of the present invention will be explained in detail below with reference to the illustrated embodiments.

2 and 3 show an embodiment of the present invention,
In these figures, 1 is an iron core formed by winding a copper strip.

The iron core 1 consists of leg parts it, 11 and yoke parts 12, 12, and each leg part 11 is wound with high and low voltage windings 2 arranged concentrically.

Inner corner portion 11a of each leg portion 11 located on the core window 13 side.
11a and the outer corner 11 located on the opposite side of the iron core window 13
b. 11b has rounded corners, and similarly, the inner and outer corners 12a, 12a and 12b, 12b of the yoke portion 12 have rounded corners.

In this case, the outer corners 1lb and 12b are closer to the inner corner 11.
a, 12a, and each leg 11
A straight line YY' drawn in a direction perpendicular to the narrow width direction of the cross section (in the illustrated example, the direction in which the steel strips are laminated) so as to divide the area of the cross section of the yoke portion 12 into two equal parts is the cross section. The shape of the cross section of each leg portion and the yoke portion is asymmetrically formed so as to pass through a position closer to the iron core window 13 side than a point P that bisects the maximum dimension in the narrow width direction.

By forming the iron core as described above, at least one of the iron core material and the copper wire material can be saved.

First, the cross-sectional area of the core and the average circumference of the core as viewed from the orientation shown in FIG. 2 are made the same as before (that is, the core volume is made the same as before).

) and the cross sections of each leg and yoke of the iron core are made irregularly shaped as described above, the envelope 11e of the edge of the cross section of each leg is
The length of the director's office can be made shorter than before.

Therefore, in this case, the average length of the winding can be shortened to reduce the amount of copper wire used, and copper loss can be reduced.

Next, we will calculate the cross-sectional area of the core and the envelope 1 of the edge of the cross-section of the core.
When the circumference of 1e and the dimensions of the core window 130 are the same as before and the shapes of each leg and yoke are modified as described above (
That is, if the amount of copper wire used is the same as in the past), the average circumference of the iron core can be made shorter than in the past, and the volume of the iron core can be reduced.

Therefore, in this case, the amount of iron can be reduced,
Iron loss can be reduced.

In addition, when the cross-sectional area of the core and the dimensions of the core window are the same as before and the legs and yoke are deformed as described above, the average length of the core and the circumference of the envelope of the edge of the cross-section of the core can be made smaller than before, and both the amount of iron and the amount of copper can be reduced.

Furthermore, the cross-sectional area of the core and the dimensions of the core window are the same as before, and either the average length of the core or the circumference of the envelope of the edge of the cross section of the core legs and yoke parts are made larger than before. In some cases, the other can be reduced by an amount that exceeds the increase, and either the iron amount or the copper amount can be significantly reduced.

In the example shown in FIGS. 2 and 3, each corner of the cross section of the legs and yoke of the core is stepped down, but the fourth
Each corner may be rounded as shown in the figure, or each corner may be cut diagonally in a straight line as shown in FIG.

Furthermore, these shapes can be combined as appropriate.

In order to manufacture the iron core 1 having the irregularly shaped legs and yoke parts as described above, for example, from a copper strip having a length approximately twice the average circumference of the iron core, a steel having a width dimension calculated is made. Cut the strip into widths one by one.

The steel strip thus obtained is wound in a predetermined order to form a circular iron core having an irregular cross section, and then this circular iron core is formed into a rectangular or oval shape and annealed.

On the other hand, the winding wire is wound around an irregularly shaped winding frame that matches the shape of the core legs, and the steel strips of the annealed core are removed from the inside and wound one after another into the winding frame to wind the winding around the core.

In the above embodiment, the cross section of the core is formed symmetrically with respect to the illustrated xx' axis, but it can also be made asymmetrical with respect to the XX axis.

In the above explanation, the cross sections of both the legs and the yoke of the iron core are made asymmetric, but the yoke may be formed in the same way as before with only the cross section of the legs being asymmetric. .

In addition, in the case of stacked cores, it goes without saying that the lamination direction may be positioned perpendicular to the above-mentioned lamination direction. It goes without saying that a similar effect can be obtained by making it asymmetric.

In order to shorten the average length of the core by making the shape of the cross-sectional shape of the legs of the core asymmetrical, it is possible to shorten the average length of the core by reducing only the outer corners of the legs without reducing the inner corners (corners on the window side of the core). It is possible to reduce the corners, but if you do not reduce the corners on the inside corners of the legs, you will not be able to tighten the winding sufficiently when winding, so increase the mechanical strength of the winding. I can't.

Therefore, in the present invention, it is necessary to round down both the inner and outer corners of the leg.

In the above embodiment, a single-phase transformer was taken as an example, but the present invention can also be applied to a core type three-phase transformer using a three-legged core.

In this case, both legs of the three-legged core or both legs and each yoke are formed into the same irregular shape as described above.

As described above, according to the present invention, when cutting the same inner and outer corners of the legs of the iron core, the outer corners are dropped more than the inner corners of the legs. Since the cross section has an asymmetrical shape, the amount of iron or the amount of copper, or both the amount of iron and the amount of copper can be made smaller than before.

Therefore, it is possible to reduce the electrical loss of the transformer, and there is an advantage that the cost of the transformer can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the cross-sectional shape of the core of a conventional transformer, FIGS. 4 and 5 are cross-sectional views showing different modifications of the iron core used in the present invention, respectively. DESCRIPTION OF SYMBOLS 1... Iron core, 11... Leg part, lla... Inner corner part, 1lb... Outer corner part, 12... Yoke part, 2...
winding.

Claims (1)

[Claims] 1. In a core type transformer in which a winding is wound around a core formed by laminating steel strips or steel plates, the core has an inner corner located on the core window side and an outer corner located on the opposite side from the core window. The irregularly shaped leg has a cross section having a shape other than a rectangle by cutting corners, and the irregularly shaped leg is arranged in a direction perpendicular to the narrow width direction of the leg so as to divide the area of the cross section into two equal parts. An inner iron type transformation characterized by being formed in an asymmetrical shape so that a straight line drawn on the cross section passes through a position closer to the iron core window side than a point that bisects the maximum dimension in the narrow width direction of the cross section. vessel.