JP2003188026A - Laminated sheet coil, and transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive thin transformer of high producibility by reducing heat generation caused by copper loss in large current energization and by reducing the number of components. <P>SOLUTION: A plurality of coil-like copper foil patterns 3 are formed on a sheet-like printed substrate 1, and patterns are continuously connected in a headroll form. A core magnetic leg insertion hole 5 is provided at the center part of each coil pattern, and lead-out terminals 7, 8 for external connection are provided at both ends of a copper foil substrate. A substrate is folded into a bellows shape alternately at copper foil parts 4, 6, magnetic leg insertion holes 5, 9 provided at the center part of the substrate are inserted to a core magnetic leg 13 such as ferrite, and external lead-out terminals 7, 10 and 8, 11 are connected each, thus forming a two-terminal parallel connection type laminated sheet coil. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coil as an electronic component, a sheet laminated coil used for a transformer, and a transformer.

[0002]

2. Description of the Related Art A conventional coil or transformer as an electronic component has the following structure. (1) A thin wire having an insulating coating on copper is wound around a bobbin provided with a core magnetic leg insertion hole a predetermined number of times, and then the core magnetic leg insertion hole is incorporated into the core magnetic leg to form a coil and a transformer. ing. In the case of such a configuration, the thickness of the thin copper wire wound around the bobbin is set to be thicker as the current flowing through the bobbin becomes larger, so that the winding height is inevitably increased. Therefore, this winding height affects the overall height dimension of the product, resulting in a high height. Further, there is a problem that pinholes in the insulating film formed on the surface of the thin copper wire and layer short-circuits between windings due to damage and disconnection are likely to occur. (2) A so-called sheet type in which a thin copper wire is eliminated and a copper foil pattern is formed in a coil shape on one or both sides of a sheet-shaped printed circuit board and a core magnetic leg insertion hole is provided at the center of the coil-shaped pattern. In the case of coils and transformers, when it is desired to increase the current flowing through the coil-shaped copper foil pattern, measures such as widening the area of the copper foil pattern and increasing the thickness of the copper foil film are taken. However, enlarging the pattern area with a single substrate becomes a problem against the miniaturization because the outer shape of the product becomes large. For this reason, substrates having the same pattern are laminated and the patterns of the substrates are connected to each other by contact pins or through holes to be used as a parallel connection. When the copper foil patterns on the respective substrate surfaces face each other, an insulating sheet is inserted between them to insulate. Thereafter, the core magnetic leg insertion hole provided in the substrate is incorporated in the core magnetic leg to form a coil and a transformer. In the case of such a configuration, the problem described in (1) above is eliminated, but contact pins and through holes are newly required to connect the substrates to each other, so that the manufacturing process is inefficient and the connection of this portion is unsuccessful. There are problems that defects due to completeness are likely to occur and that an insulating sheet is required.

[0003]

SUMMARY OF THE INVENTION The present invention provides a contact pin, a through hole, and an insulating sheet for connecting a copper foil pattern between small and thin substrates which are small in size and thin so that heat generation due to copper loss when a large current is applied is reduced. The purpose is to provide a sheet-type coil and a transformer which are not necessary.

[0004]

[Means for Solving the Problems] In order to solve the above problems,
In the present invention, a plurality of coil-shaped copper foil patterns 3 are formed on a sheet-shaped printed board 1. Then, each of them is arranged on a plane and adjacent coil-shaped patterns are continuously connected in a beaded shape by a copper foil pattern 4. Lead lead-out terminals 7 and 8 for external connection are provided at both ends of the coil-shaped copper foil pattern substrate, and core magnetic leg insertion holes for inserting core magnetic legs 13 of ferrite or the like are provided at the center of each coil-shaped pattern. 5 is provided. Further, the same substrate 2 having a shape symmetrical to this is laminated so that the coil-shaped copper foil pattern surfaces are overlapped with each other.

A two-terminal parallel connection type coil is formed by alternately folding two substrates in a bellows shape with the copper foil portion 4 and connecting the end lead lead-out terminals 7, 10 and 8, 11 of the two sheet coils respectively. To be done. The magnetic leg insertion holes 5 and 9 provided at the center of the folded board are inserted into the magnetic leg portion 13 of the core such as ferrite to form a sheet coil and a transformer.

According to this structure, the effective area of the copper foil pattern can be expanded without enlarging the outer shape, and it is possible to obtain a coil and a transformer which are small in size and can carry a large current. Further, since the copper foil patterns of the substrates to be laminated are continuously connected, contact pins and through holes for connecting the substrates, which are conventionally required, are unnecessary.

Since two coil-shaped copper foil patterns having the same potential as each other are connected in parallel, it is not necessary to insulate the two patterns from each other, and thus sheets for insulation are unnecessary. Further, the DC resistance is 1/2 that in the case of one sheet coil, and heat generation due to copper loss during energization can be reduced.

The shape pattern of the coil formed on the sheet substrate may be a circle, an ellipse, or a square shape, and the number of turns per unit of the pattern is also limited to 1/2 or 3/4. Instead, it can be set arbitrarily. Further, the number of substrates to be laminated and the thickness of the copper foil formed on the sheet substrate can be freely changed according to the required specifications.

The shape of the core magnetic leg insertion hole provided on the substrate is preferably elliptical in terms of magnetic characteristics, but may be circular or square.

Since the coil according to this structure does not use a copper thin wire, pinholes in the copper coating insulation coat, layer shorts due to wear, disconnection, etc. do not occur, and are highly reliable.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram showing an embodiment of the present invention.
In FIG. 1a, a plurality of 3/4 coil-shaped copper foil patterns 3 are formed on one sheet-shaped printed circuit board 1. The coil-shaped copper foil patterns arranged adjacent to each other are continuously connected to each other by the copper foil pattern 4 in a beaded shape. The width of the copper foil pattern and the copper foil film thickness are set by the current-carrying current specifications, and the number of coiled copper foil patterns is set by the required coil inductance specifications. At both ends of the coil-shaped copper foil pattern substrate, projections 7 and 8 obtained by extending the copper foil pattern for use as lead-out terminals for external connection are provided, and at the center of each coil-shaped copper foil pattern, a core magnet such as ferrite is formed. FIG. 7 is a plan view showing that the leg insertion hole 5 is provided.

FIG. 1b is a plan view showing the structure of a further substrate 2 having a shape symmetrical to the above-mentioned substrate. FIG. 2 shows the substrates 1 and 2 having such a structure so that their coiled pattern surfaces are overlapped with each other. It is a perspective view showing the state where it laminated. FIG. 3 shows a state in which these boards are alternately folded in a bellows shape by the copper foil portions 4 and 6 and lead lead terminals 7, 10 and 8 and 11 provided at both ends of the coiled copper foil pattern board are connected. FIG. In the example of the copper foil pattern of the substrate shown in the figure, the number of turns of the entire coil is 2 turns and 1/4.

FIG. 5 shows that the magnetic leg insertion holes 5 and 9 provided at the center of the folded substrate are inserted into the core magnetic leg 13 such as ferrite to form a laminated sheet coil of two-terminal parallel connection. It is a perspective view shown, and a sheet type transformer can also be constructed by combining the sheet coil of this embodiment with another substrate of the same structure.

[0014]

According to the present invention, the symmetrical coil-shaped copper foil pattern surfaces provided on the two sheet-shaped printed circuit boards are stacked so as to face each other, and the two boards are folded and stacked in a bellows shape. Since the structure is adopted and both ends of the copper foil of each substrate are connected to each other, the present coil as a whole forms a sheet coil of a two-terminal parallel type circuit. Therefore, the effective area of the copper foil pattern can be expanded without enlarging the outer shape, and the DC resistance of the coil is 1/2 that in the case of one sheet coil. Therefore, it is possible to obtain a coil or a transformer that can reduce heat generation due to copper loss during energization and can conduct a large current. Furthermore, since the copper foil patterns of each board to be laminated are continuously connected, it is possible to eliminate the need for contact pins or through holes for connection between boards, which was conventionally required.
Further, since two copper foil patterns having the same potential are laminated so as to face each other, there is no need to insulate between the two copper foils, so an insulating sheet for this is also unnecessary, and the number of parts can be reduced and the number of assembly steps can be simplified. .

[Brief description of drawings]

1 is a view showing an embodiment of the present invention, in which FIG. 1a shows a plurality of coil-shaped copper foil patterns 3 formed on one sheet-shaped printed circuit board 1 arranged on a plane, and The coils are continuously connected in a beaded pattern with a copper foil pattern 4,
Further, it is a plan view showing a configuration in which an insertion hole 5 for inserting a core magnetic leg 13 such as ferrite is provided in the center of each coil. FIG. 1b is a plan view showing a sheet-shaped printed circuit board 2 having a symmetrical shape to the above, a plurality of coil-shaped copper foil patterns 12 and magnetic leg insertion holes 9 formed thereon. Lead-out terminals 7, 8, 10, 11 for external connection are provided on both ends of the coil-shaped copper foil pattern.

FIG. 2 is a perspective view showing that two substrates are arranged such that their coil-shaped pattern surfaces overlap each other.

FIG. 3 is a perspective view showing a state in which two substrates, on which coil-shaped copper foil pattern surfaces are overlapped with each other, are alternately folded into a bellows shape.

FIG. 4 shows a part of the cross section of FIG.

FIG. 5 is a perspective view showing that a sheet type coil is constructed by inserting magnetic leg insertion holes 5 and 9 provided at the center of a coiled pattern of a folded sheet substrate into a core magnetic leg 11 made of ferrite or the like. . By connecting the external lead terminals 7, 10 and 8, 11 in this configuration, a two-terminal parallel connection type laminated coil is formed. A sheet type transformer can be constructed by further combining the above sheet coil with another substrate having the same structure.

6 is an embodiment showing that a part of the plurality of coil-shaped copper foil patterns 3 shown in FIG. 1 is extended and a third external lead terminal 14 is provided.

[Explanation of symbols]

1, 2 sheet printed circuit boards 3, 12 coiled copper foil pattern Copper foil pattern for 4, 6 connection 5, 9 Core magnetic leg insertion hole 7, 8, 10, 11, 14 Lead-out terminal for external connection 13-core magnetic leg 15 Resin base material

Claims (4)

[Claims] 1. A plurality of coil-shaped copper foil patterns are formed on a sheet-shaped printed circuit board. Each of them is arranged on a plane and adjacent coil-shaped patterns are continuously connected in a bead-shaped copper foil pattern. A sheet-type coil or transformer, wherein further similar substrates having mutually symmetrical shapes are laminated so that their coil-shaped pattern surfaces overlap each other. 2. A sheet-type coil or a transformer, wherein two substrates, which are laminated so that coiled copper foil pattern surfaces are overlapped with each other, are folded in a bellows shape to form a two-terminal parallel connection coil. 3. A sheet-type coil or a transformer, wherein a core magnetic leg insertion hole of ferrite or the like is provided at the center of the coil-shaped pattern according to claim 1. 4. A sheet-type coil or transformer, wherein the core magnetic leg insertion hole according to claim 3 is incorporated in a core magnetic leg made of ferrite or the like.