JPH01196109A - Small-sized transformer-coil - Google Patents

Abstract

PURPOSE:To manufacture a small-sized transformer-coil without using a spool, to increase the sectional area of a magnetic core only by a section correspond ing to the sectional area of the spool and to scale down the shape of the transformer-coil by integrating an electric insulating film and a surface mounting terminal on the surface of the integrally-formed closed magnetic circuit magnetic core by an insulating material and executing a linear winding on the magnetic core. CONSTITUTION:Electric insulating films 7 are formed on the surfaces of the squarish 8-shaped closed magnetic circuit magnetic core 8 with an intermediate leg 9 and the inner leg 9 by an insulating material (a phenol resin, an epoxy resin) while surface mounting terminals 5 are buried in grooves at the positions of terminals previously shaped to the magnetic core by employing an epoxy molding resin 10. A winding 6 is wound on the inner leg 9, and a lead for the winding is passed through guide grooves 4 previously formed to the magnetic core and bound on the surface mounting terminals 5, thus manufacturing a transformer or a coil. The winding is wound, the terminals of the winding are connected to the terminals and impregnated with varnish, etc., and sections among the winding are insulated, thus completing the transformer-coil.

Description

[Detailed Description of the Invention] [Overview of the Field] The present invention relates to a small transformer/coil for surface mounting in which wires are directly wound around an oval-shaped or Japanese-shaped magnetic core with no air gaps in the magnetic path. be.

[Contents and problems of conventional technology]

Conventionally, small transformers and coils for surface mounting have been made by winding a wire around a winding frame with terminals for surface mounting on the flange, inserting the divided magnetic core into the winding frame, and using adhesive tape or a core holder.
Winding frame with magnetic core 2-side mounting terminal Also, since a winding frame for winding is always used, the thickness of the winding frame is required when reducing the size of transformer coils, and the winding space is reduced, making it possible to reduce the size of small transformers.・There was a problem in making the coil.

[Object of the invention] □ The present invention conventionally involves winding transformer coils in advance by winding them around a winding frame, and then fitting the divided magnetic cores into the winding frame.
In contrast to conventional transformers or coils, windings are wound directly onto a magnetic core whose surface is covered with an electrically insulating film without using a winding frame. A transformer coil is created by soldering the surface mount terminal winding ends, making it a small surface mount transformer.
The purpose is to provide coils.

[Structure of the invention]

Traditionally, transformer coils were wound using a winding frame, but recently transformer coils, especially for switching power supplies, have higher excitation frequencies, the magnetic core is smaller, and the number of turns can be reduced. There is no longer a significant difference between the man-hours involved in winding the frame and the man-hours required to wind the wire directly on the magnetic core, and it is also possible to wind the wire directly on a Japanese-shaped magnetic core or an oval-shaped magnetic core with no air gaps in the magnetic path. Although this was difficult in the past, a winding machine that directly winds the wire on the center leg of the Japanese-shaped magnetic core was also developed, and the present invention was made possible by the advent of these winding machines.

On the other hand, magnetic cores for high-frequency, small-capacity transformers are becoming smaller and smaller.
The method of configuring a transformer/coil by combining magnetic cores has limitations in terms of miniaturization, and the transformer coil of the present invention is constructed without using a winding frame. The cross-sectional area of the magnetic core can be increased by an amount corresponding to the cross-sectional area of , the number of turns can be reduced, and the shape of the transformer coil can be made smaller accordingly.

〔Example〕

Hereinafter, the present invention will be explained using the drawings.

3 and 4 are perspective views of conventional transformer coils.

In FIG. 3, ] is an E-type magnetic core, and 2 is a winding frame around which a winding wire is wound when forming a transformer coil.

A surface mount terminal 5 and a guide groove 4 for guiding the winding wire from the winding frame to the surface mount terminal are attached to the collar 3 of the winding frame.

When constructing a transformer coil, the winding is wound around the winding frame, the winding is soldered through the guide groove 4 to the surface mount terminal 5, and then the E-type magnetic core 1 (hereinafter referred to as the magnetic core) is attached to the winding frame. It had built-in transformer coils from both sides. FIG. 4 shows the assembled state.

In the conventional transformer coil configuration, a winding frame for winding the winding wire is prepared in advance, the winding is applied to the winding frame in advance, and the magnetic core is assembled. This required an extra space equivalent to the cross-sectional area of the winding frame, and the shape of the magnetic core therefore became that much larger.

1 and 2 are perspective views showing the structure of a transformer coil according to an embodiment of the present invention. In FIG. 1, the magnetic core is a so-called Japanese-shaped closed magnetic circuit magnetic core 8 with a middle leg 9, and the surface of the middle leg 9 is coated with an electrically insulating coating 7 using an insulating material (phenol-based or epoxy-based resin), and at the same time is surface-mounted. The terminal 5 is implanted in a groove at the terminal position, which is previously provided in the magnetic core, using an epoxy molding resin 10. The winding 6 is wound around the middle leg 9, the lead wire of the winding is passed through the guide groove 4 provided in advance in the magnetic core, and the surface mount terminal 5 is connected to a transformer or coil. Shown in Figure 2. Trance·
The coil is wound, the end of the winding is connected to the terminal, and then impregnated with varnish etc. to insulate between the windings.

In addition, in the present invention, the surface mount terminal is installed and fixed in a groove or recess provided in the magnetic core in advance using thermosetting molded resin, but without using a groove or the like for installing in advance in the magnetic core, The surface mount terminal may be constructed by integrally molding the surface mount terminal and the magnetic core in advance using a molding resin such as a thermosetting resin on a magnetic core whose surface has been electrically insulated.

〔Effect of the invention〕

By using a closed magnetic circuit magnetic core, the present invention can reduce variations in electrical characteristics, eliminate the need for processes such as polishing of joint surfaces that are required with split-type magnetic cores, and furthermore, because it does not have a winding frame for winding, it is compact. Transformer coils can be provided.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a closed magnetic circuit magnetic core with a surface mount terminal of the present invention, in which (a) is a perspective view, and (b) is a sectional view taken from section AA in (a). FIG. 2 is a perspective view showing a pair of transformer coils according to the present invention. FIG. 3 is a perspective view showing an E-shaped magnetic core and a winding frame that constitute a conventional transformer coil. FIG. 4 is a perspective view showing the assembly of a conventional transformer coil. Below is the margin ■... E-type magnetic core. 2... Winding frame. 3... Tsuba. 4...
・Guide groove. 5...Surface mount terminal. 6... Winding wire. 7... Electrical insulation film. 8... Japanese-shaped closed magnetic circuit core. 9...middle leg. 10... Molding resin. Patent applicant: Tohoku Metal Industry Co., Ltd. Figure 1 (G) Figure 2

Claims (1)

[Claims] In transformer coils, which consist of windings around a magnetic core,
A small transformer/coil characterized by having an electrical insulating film and surface mount terminals integrally molded with an insulating material on the surface of an integrally molded closed magnetic circuit magnetic core, and winding wires directly on the magnetic core.