JPH0722252A - Multilayer inductor - Google Patents

Abstract

(57) [Abstract] [Purpose] In a laminated inductor using a flat conductor for the coil conductor, the electric insulation withstand voltage characteristics between the coil conductors are not used, without using the resin insulation film interposed between the coil conductors. And a multilayer inductor that ensures automatic assembly. [Configuration] The surface of the laminate to flat conductor of the coil conductor 2 formed in advance electrical insulating film, ridges 4 in the example primary coil 2a of laminating in contact with each other of the coil conductors 2
In addition, the ridge 5 is formed on the secondary coil 2b at a position not overlapping with the primary coil 2a at the time of coiling and laminated, and after the coil conductor is laminated, the entire coil conductor is molded with an insulating resin. Impregnation is performed with an insulating varnish.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer and various coils which are mounted on an electronic circuit and have a reduced board mounting height.
The present invention relates to a laminated inductor made by using a thin copper plate as a winding conductor.

[0002]

2. Description of the Related Art Conventionally, in the case of an inductor such as a transformer or a choke coil which has a low board mounting height or is used at a high frequency, the coil conductor portion is made of a thin copper plate having a flat thickness as shown in FIGS. The laminated inductor that was used is
In the case of the transformer of the laminated inductor, the primary side coil and the secondary side coil are formed by being laminated in order to enhance electromagnetic coupling between the primary side coil and the secondary side coil.
In order to ensure the insulation between the primary coil 20a and the secondary coil 20b, an insulating film 10 made of a resin film having an electrical insulation characteristic is inserted between the flat primary coil and the secondary coil, Since the latter is resin-molded, there are problems that the number of parts is large to form the inductor, and that the assembly is labor-intensive and automatic assembly is difficult.

[0003]

SUMMARY OF THE INVENTION The present invention eliminates such drawbacks, and is an inexpensive multilayer laminated inductor comprising a primary coil and a secondary coil using a thin flat copper plate. The secondary coil and the secondary coil can be easily stacked, the automatic assembly is easy, and the electrical withstand voltage of the primary coil and the secondary coil is guaranteed, and the creepage of the primary coil and the secondary coil is ensured. It is an object of the present invention to provide a laminated inductor that secures a distance.

[0004]

According to the present invention, a flat copper plate forming a transformer of a laminated inductor or a coil conductor of a choke coil is preliminarily formed with an electrically insulating coating of polyurethane or polyimide resin. When punching into a coil shape, punching is performed from the upper surface of the film to form a coil conductor made of copper plates on which a ridge is formed at different positions to be laminated, on one part or the entire surface of the plate forming the coil conductor,
A gap is formed on the end faces between the laminated coil conductors by the convex stripes formed on the coil conductors, and the end faces of the copper plates exposed at the cut end faces formed during punching of the coil conductor during resin molding or varnish impregnation are electrically insulated. Mold resin or insulating varnish is filled between the copper plates to ensure electrical insulation between the copper plate end faces exposed during cutting. The electrical withstand voltage between the primary side coil and the secondary side coil is determined by the thickness of the resin such as polyester resin or polyimide resin applied in advance on the surface of the copper plate forming the coil conductor, and the copper plate forming the coil conductor. It is achieved by selecting the height of the ridge, that is, the thickness of the gap between the coil end faces into which the molding resin forming the coil conductor is injected.

That is, according to the present invention, in a laminated inductor in which an EE type magnetic core is assembled to a coil conductor in which flat electric conductive plates are laminated so as to form a closed magnetic circuit, the laminated coil conductors are flat electric conductive layers. It is characterized in that the surface of the plate is coated with an electric insulation film in advance, ridges are provided so as not to overlap with each other on the joint surface to be laminated, and molded with an insulating resin or subjected to an insulating treatment with an insulating varnish. It is a laminated inductor.

[0006]

[Function] An insulating coating film is formed on the surface of a flat copper plate forming the primary coil and the secondary coil by selecting polyurethane resin or polyimide resin according to the heat resistance characteristics of the coil conductor required in advance. Incidentally, at the time of punching the coil conductors, ridges are formed at different positions on the plate surface between the punching of the shape and the adjacent coil conductors so that the stacking positions do not overlap each other. Therefore, when the coil conductors are stacked by the height of the ridges formed on the plate surface of the coil conductor, the gaps between the end faces of the coil conductors can be separated from each other. The metal surfaces of the copper are separated from each other, and during resin molding or varnish impregnation processing performed before or after the inductor is assembled, the resin or varnish is introduced between the coil conductors and solidified, so that The electrical withstand voltage characteristic of the secondary coil becomes reliable. On the other hand, since it is not necessary to interpose an insulating film when the coil conductors are laminated, it is easy to assemble the laminated inductor, and the coil conductors can be automatically assembled.

[0007]

Embodiments of the present invention will be described with reference to the drawings. Figure 1
Is a diagram showing a primary side coil 2a and a secondary side coil 2b forming a laminated transformer according to the present invention.
The terminal connection sides of the secondary coil 2b and the secondary coil 2b are drawn out in opposite directions. FIG. 2 is an enlarged cross-sectional view taken along the line AA in FIG. 1, in which the ridges 4 of the primary coil 2a and the ridges 5 of the secondary coil 2b overlap each other on a flat surface, that is, the primary side. The ridges 5 of the secondary coil 2b are formed on both sides of the ridge 4 of the coil 2a, and the coil conductor 2 is formed by the primary coil 2a and the secondary coil 2b.

On the surface of the coil conductor made of a copper plate forming the primary side coil 2a and the secondary side coil 2b, an insulating film 3 made of polyurethane resin is formed in advance before coil punching.
Alternatively, if the operating temperature is high or the heat generation temperature from the coil conductor is high, an insulating film 3 made of polyimide resin on the surface
Is formed, and the primary side coil and the secondary side coil are laminated without interposing an insulating film as in the conventional case. Normally, the thickness of the coil conductor of a laminated inductor is 0.3
mm or less, the coil conductor to be laminated is also the primary coil,
Even if the secondary coil is combined, it is at most 30 layers or less,
In particular, the field in which this type of laminated inductor is used is in the field of high frequencies, and the plate thickness of the coil to be laminated is thin because the influence of the skin effect at high frequencies is reduced, and the number of laminated layers is small. Further, the height of the convex stripes formed on the laminated surface of the coil should be 0.2 at most because gaps may be formed between the laminated coils.
mm is sufficient, and is determined by the value of the voltage applied between the coil conductors.

In the embodiment of the present invention, the primary side coil, 2
The ridges of the secondary coil are circular in cross section, but the ridges do not have to be circular in cross section, and the cross section of the ridges is 90 degrees between two orthogonal planes having R faces at the corners. It may have a stepped shape or a ladder shape.

FIG. 3 shows a laminated inductor according to the present invention, in which the primary coil 2 and the primary coil 2 shown in FIGS.
a, the secondary coil 2b is connected to both ends of the coil bobbin 7 and the terminal of the coil conductor is connected to the pin terminal 8 (the secondary terminal is not shown), and the EE type magnetic core 6 is incorporated into the two-dot chain line. The shape shown by (1) is molded with the insulating resin 9 to improve the electric insulating property between the built-in parts, or the varnish impregnation process is performed. Since it is a laminated inductor formed in this way, when molding with insulating resin or impregnating varnish,
The insulating resin is injected into the gap formed by the ridge between the primary coil and the secondary coil, and the electrical insulation withstand voltage between the primary coil and the secondary coil is significantly improved. Further, since the insulating film is formed on the coil surface in advance, it is not necessary to insert the insulating film into the gap when the coil conductors are laminated as in the conventional case, so that the assembly of the coil conductor can be automated. Although the embodiment of the present invention has been described by taking the transformer as an example, the present invention can be similarly applied to a choke coil used at a high frequency.

[0011]

EFFECTS OF THE INVENTION An insulating film is formed in advance on a laminated surface of a coil conductor made of a flat copper plate of a laminated inductor forming a transformer or a choke coil, and a ridge is formed at a position not overlapping each other on the laminated surface. By using the coil conductor that has been formed, it is not necessary to use the resin insulating film inserted between the coil conductors in the conventional laminated inductor of this kind, and the assembling work when assembling the laminated inductor is easy. In addition, since the end face of the coil conductor formed by punching creates a gap between the coil conductor faces by the height of the ridge, when molding with resin after coil conductor assembly or varnish impregnation treatment, A multilayer inductor that facilitates the injection of resin or varnish into the coil conductor layers, guarantees the electrical breakdown voltage characteristics between coil conductors, and enables automatic assembly. Test can be.

[Brief description of drawings]

FIG. 1 is an external perspective view showing the shape of a coil conductor of a laminated inductor according to the present invention.

FIG. 2 is a diagram of coil conductor A of the multilayer inductor shown in FIG.
-A sectional enlarged view taken along line A.

FIG. 3 is an external perspective view showing a laminated inductor according to the present invention.

FIG. 4 is an external perspective view of a laminated coil conductor used in a conventional laminated inductor.

5 is an enlarged cross-sectional view taken along the line BB of FIG.

[Explanation of symbols]

1 Gap between coils 2 Coil conductors 2a, 20a Primary coil 2b, 20b Secondary coil 3 Insulation film 4 Convex strip 5 Convex strip 6 Magnetic core 7 Coil bobbin 8 Pin terminal 9 Insulating resin 10 Insulating film

Claims (1)

[Claims] 1. In a laminated inductor in which an EE type magnetic core is assembled to a coil conductor in which flat electric conduction plates are laminated so as to form a closed magnetic circuit, the laminated coil conductors are the surface of the flat electric conduction plate. Is coated with an electric insulating film in advance, and a ridge is provided so that the joint surfaces to be laminated do not overlap each other, and is molded with an insulating resin, or is subjected to an insulating treatment with an insulating varnish, which is a laminated inductor. .