JPS6174311A - Transformer having coil formed of superposed wiring body - Google Patents

Abstract

PURPOSE:To facilitate the manufacture of a thin-type transformer, by using as a coil a superposed wiring body which is prepared by superposing a plurality of insulating sheets with a coil conductor pattern formed thereon, and by connecting each sheet coil conductor with another. CONSTITUTION:A superposed wiring body 1 is prepared by superposing in many layers sheet coils each of which is made by forming a coil conductor pattern 5 on a thin insulating sheet. These sheet coils are disposed in such a sequence that enables the best electromagnetic connection of each coil of a multi-winding coil with another, and the conductor pattern of each sheet coil is connected with that of another by connecting conductors 2 so that the multi-winding coil of a transformer is formed as a whole. Some of the connective conductors 2 are extended in the longitudinal direction so that they form pin terminal 3 which serve as means for connection to a printed circuit and for fixation of the transformer. Cores 4 and 4' are manufactured in the form of being divided into two pieces, upper and lower pieces, and the two pieces are put together with the superposed wiring body 1 held between, so as to form the magnetic circuit of the transformer. In this way, the flat and transformer is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to small transformers, particularly thin transformers that are mounted on a printed wiring board together with other electronic components.

(Prior Art) A transformer has a plurality of coils, and in particular, a transformer used with an electronic circuit, such as a converter transformer for DC voltage conversion, is a multi-winding transformer having at least six coils.

Generally, these fills have different numbers of turns and wire thicknesses, and are conventionally manufactured by winding using enamelled copper wire.

There is a plastic winding frame for holding each coil, and usually about 10 pin terminals are attached to a terminal attachment part formed integrally with the frame or separately.

Both ends of each of the above-mentioned coils are connected to these pin terminals.9 By soldering the pin terminals to the connection lands of the printed wiring board, connections between the coils and external circuits and to the printed wiring board of the transformer itself are made. is now being fixed.

The magnetic circuit usually consists of an E-shaped ferrite core.

(Problem to be solved by the invention) Transformers used in combination with electronic circuits, such as DC
- DC converter transformers and the like are often mounted on printed wiring boards alongside other electronic components, such as ICs and capacitors, and the dimensions of the transformer are small;
In particular, it is desired that the height be lower than that between other electronic components.

However, conventionally, manufacturing a small multi-winding transformer coil using wire windings has the drawbacks of decreasing the conductor space factor and increasing the ratio of the winding frame and pin terminal mounting area to the overall size of the transformer. This made it difficult to downsize the transformer.

In addition, the smaller the transformer, the more difficult it is to connect each coil to the pin terminals at both ends, which often poses a problem in automating manufacturing and ensuring reliability.

It is an object of the present invention to eliminate the drawbacks that impede the miniaturization of multi-winding transformers, and to facilitate the manufacture of small, particularly thin transformers.

(Means for Solving the Problems) In the transformer of the present invention, a plurality of sheet coils each having a coil conductor pattern formed on a thin insulating sheet are laminated, and each of the four sheet coils is connected with a connecting conductor. The connected laminated wiring body is used as a coil.

Specifically, for example, a laminated wiring body manufactured by the manufacturing method described in Japanese Patent Application No. 58-31432 can be used. A coil made of a laminated wiring body maintains its coil shape by itself, so a winding frame is not used.

Further, since it is easy to manufacture a coil made of a laminated wiring body into a flat and thin shape, a flat and thin core is also used, so that the shape of the entire transformer is configured to be flat and thin.

In a multi-winding transformer, it is desirable to arrange the turns of the conductor belonging to one coil in a distributed manner in order to improve the degree of electromagnetic coupling between each coil. However, with the conventional winding method, In this case, it was extremely difficult to implement from a productivity standpoint.

In the case of a coil made of a laminated wiring body, the sheet coils belonging to one coil are ideally distributed in accordance with the design requirements of the transformer, and the distributed sheet coils are connected to each other by connecting conductors that pass through the connecting portions. Prevent the conductor space factor from decreasing due to connection.

In the present invention, one end or both ends of the connecting conductor are extended beyond the thickness of the laminated wiring body, and the extended portion is configured to serve as a bin terminal of the transformer. This eliminates the need for a conventional winding frame and a terminal mounting portion provided integrally or separately therewith.

(Function) By using a laminated wiring body as a coil, it becomes easy to manufacture flat and thin transformers, and even if the coil conductors are distributed, especially in small multi-winding transformers, the conductor space factor will deteriorate. This makes it easy to downsize the device.

Note: The connecting conductor that connects the coils also serves as the transformer's pin terminals, so there is no need for a small number of terminals to fix the pin terminals, and there is no need for a coil winding frame, which helps make the transformer more compact. It is effective and contributes to reducing the number of parts.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

The laminated wiring body 1 is a multilayer stack of sheet coils each having a coil conductor pattern 5 formed on a thin insulating sheet, and each sheet coil is arranged in an order that provides the best electromagnetic coupling between the coils of the multi-winding coil. The conductor patterns of each sheet coil are connected to each other by connecting conductors 2, forming a multi-winding coil of the transformer as a whole. A portion of the connecting conductor 2 is extended in the longitudinal direction to form a pin terminal 3, which serves as a means for connection to a circuit on a printed circuit board (not shown) and for fixing the transformer.

The cores 4 and 4' are manufactured in the form of two pieces, upper and lower, and by putting the two pieces together so as to sandwich the laminated wiring body 1, a magnetic circuit of 6 transformers is formed, and a flat and thin transformer is completed. .

(Effect of the invention) As a result of comparing the example with a conventional winding type transformer having the same characteristics, the height of the transformer of the present invention is extremely thin at 8.5 cm, compared to 23 cm for the conventional transformer, and the height of the transformer as a whole is 23 cm. It was also confirmed that the transformer of the present invention has the effect of reducing the size by 58% compared to the conventional transformer.

[Brief explanation of the drawing]

The drawings show an embodiment of the transformer of the present invention; FIG. 1 is a partially cutaway front view, FIG. 2 is a partially cutaway plan view, and FIG. 3 is a side view. 1: Laminated wiring body, 2: Connection conductor, 3: Pin terminal, 4, (
: Core patent applicant: Kangyo Denkiki Co., Ltd. No. 1 B-8' axis plane ← Fig. 2

Claims (2)

[Claims] (1) A patterned conductor with a thickness of about 0.01 to 0.2 mm is formed on an insulating sheet with a thickness of 0.03 mm or less,
A plurality of the insulating sheets are laminated to form a laminate, and a connection conductor layer is formed as the pattern conductor on each of the sheets at the connection part of the laminate, and a through hole is formed in the connection part, A connecting conductor is press-fitted into the through hole, and the circumferential surface of the connecting conductor and the inner circumferential surface of the hole in each of the connecting conductor layers opened by the through hole of the connecting portion are connected to each other by solder. A transformer characterized by having a laminated wiring body as a coil. (2) The transformer according to claim 1, wherein at least one end of the connecting conductor is extended to form a pin terminal.