JPH06163280A - Ring core with circular cross section and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a high quality wound core for electromagnetic parts which core is easy to be manufactured and suitable for mass-production. CONSTITUTION:A belt type electromagnetic steel plate is wound in a cylinder type, and a cylindrical core having a nearly square section is formed. After that, angular parts at four peripheral corners are cut and eliminated. Thereby a ring core 1' wherein the sectional shape of the whole periphery is approximate to a true circle is manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wound core core used in transformers, reactors and the like, and more particularly to an annular ring core having a circular cross section which is excellent in workability during manufacturing of the transformer and is also excellent in quality. And the manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, as a core of this kind, Japanese Patent Publication No.
Some of them have a polygonal cross section as shown in No. 4-24605, and some have a rectangular tube shape with a substantially circular cross section as shown in Japanese Patent Publication No. 61-22851.

In the manufacturing method, the former is a method in which a long strip of silicon steel is gradually cut by sandwiching a strip of silicon steel wound in a cylindrical shape together with paper or the like between metal fittings of a predetermined shape and cutting the strip. A plurality of silicon steel strips that have been formed into a contracted shape and then similarly formed are sequentially wound in the order of width to form a rectangular tube-shaped core having a polygonal cross section, and the latter is wound. In this case, the strip material of the core is cut out in advance so as to obtain a circular cross section, and the strip material is wound into a rectangular tube shape.

[0004]

Since the planar shape of each of the above-mentioned conventional cores is a rectangular tube, magnetic flux leakage occurs at the ends, and the entire surface of the iron core is covered with a conductive wire, so that leakage magnetic flux is generated. The quality was inferior to the ring-shaped ring core which hardly occurs. In addition, although the cross section is formed in a substantially circular shape, the surface of the plastic bobbin still has unevenness, so that the plastic bobbin is heavily worn during coil winding, and it is difficult to improve the winding speed, resulting in poor work efficiency. Had a point.

Further, in the manufacturing method as well, since it has been conventionally assumed that the core has a rectangular cylindrical shape, it is difficult to cut the entire circumference of the steel plate into a circular cross section after winding the steel plate, and therefore the winding is performed. The strip-shaped electromagnetic steel sheet has been previously processed into a predetermined shape.
Therefore, there is a problem that a dedicated mold is required for that purpose or that processing is difficult.

The present invention is intended to solve the above-mentioned conventional problems.

[0007]

In the present invention, in order to solve the above-mentioned conventional problems, the core is limited to an annular ring core, and the entire circumference is constituted by a circular cross section with a smooth surface. .

Further, in the manufacture, after the steel plate is wound in a cylindrical shape, the corner portions around the steel plate are cut and removed, and the cross section is processed into a substantially perfect circle.

[0009]

The ring-shaped ring core acts so as to eliminate magnetic flux leakage, and at the same time, makes it possible to easily perform corner cutting processing over the entire circumference. Further, the core whose cross section is cut into a substantially perfect circle acts to facilitate the coil winding work.

The manufacturing method by cutting after winding the steel sheet serves to simplify the work and improve the work efficiency.

[0011]

1 and 2 are a plan view and a sectional view of a ring core 1'having a circular cross section according to the present invention. As shown in the figure, the ring core 1'of the present invention has an annular planar shape and a circular cross section along the entire circumference.

FIGS. 3 and 4 show a cylindrical core 1 before being processed into a circular cross section. The core 1 is a long silicon steel plate having a predetermined width, or an electromagnetic steel plate such as permalloy or amorphous steel. 2 is wound.

Next, the manufacture of a ring core having a circular cross section by the method of the present invention will be described. First, as shown in FIGS. 3 and 4, a strip-shaped electromagnetic steel plate 2 having a width a is formed into the same thickness a'as the width a. It is wound until it is formed to form a cylindrical core 1 having a substantially square cross section. Then, as shown in FIG.
The corner portion 3 around is cut and removed by a grinder or the like, and its cross section is processed into a circle. In this way, by cutting and removing the inner and outer corners over the entire circumference of the core, as shown in FIG.
The ring core 1'of the present invention having a circular cross section as shown in FIG.
Are formed.

The ring core of the present invention manufactured in this manner is used as a transformer or a reactor by winding a conductive wire around it as in the conventional case. At this time, the ring core of the present invention is As mentioned above, since the surface is cut at the finishing stage, it has a smoother surface and has a round outer shape compared to the conventional one in which steel sheets with different widths are wound. In addition to the fact that the winding work is performed smoothly, the winding work can be performed smoothly and the speed thereof can be improved.

FIG. 6 shows another embodiment of the present invention. In this example, cutting is not performed until the cross section becomes a perfect circle,
The four corner portions 3 are cut and removed in an arc shape, leaving a slight flat portion 4.

[0016]

As described above, since the ring core having a circular cross section of the present invention has no straight portion, it is easy to wind the wire, and the conductor wire is hardly cut or deteriorated during bending. Therefore, a high quality transformer can be provided in combination with the structure in which the entire surface of the core is covered with the conductive wire and the leakage magnetic flux is unlikely to occur. Further, since the surface is formed in a smooth arc shape, the winding can be performed smoothly, the winding speed is improved, and the work efficiency is improved. Furthermore, since the length of the conductor wire wound around the core is 88.6% with respect to the square core having the same cross-sectional area, the required conductor wire can be saved, and the size can be reduced to reduce the size and weight of the transformer. There are many excellent effects.

Further, in the manufacturing method, since the steel sheet is wound and the peripheral corners are cut, no special equipment is required as in the conventional method, the work is easy, and no excessive capital investment is required. It has an excellent effect not seen in the past that mass production of high-quality cores with high yield is possible.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view of the same.

FIG. 3 is a plan view of the core before cutting.

FIG. 4 is a vertical sectional view of the same.

FIG. 5 is an explanatory cross-sectional view of a core showing a production process.

FIG. 6 is a cross-sectional explanatory view of another embodiment.

[Explanation of symbols]

 1 Core before cutting 1'Ring core 2 Electromagnetic steel plate 3 Corner part a Steel plate width a'Steel plate laminated thickness

Claims (2)

[Claims] 1. A ring core having a circular cross section, which is obtained by winding an electromagnetic steel plate such as a silicon steel plate, permalloy, or amorphous into an annular shape, and forming a substantially perfect circular cross section. 2. A strip-shaped electromagnetic steel plate is wound to form a cylindrical core having a substantially square cross section, and then the corners around the core are cut and removed, and the cross section of the entire circumference is shaped into a substantially perfect circle. A method of manufacturing a ring core having a circular cross-section.