JPH0621590A - Molded circuit board for large current - Google Patents

Abstract

PURPOSE:To simply assemble a low-cost large current circuit using a power system component by dispensing with conductor wirings. CONSTITUTION:A stud (female screw) 23 for clamping is fixed to one side surface of a thick circuit conductor 21 formed on a predetermined circuit pattern by welding. A first resin molded form 25 is integrally formed on a surface of opposite side of a stud fixing surface of the conductor 21. Further, a second resin molded form 27 is integrally formed on a stud fixing surface of the conductor 21. The conductor 21 is buried between the forms 25 and 27, and a heat of the stud 23 protrudes from the front surface of the form 27. The form 25 is a flat plate state, but the form 27 is formed in a box shape to be used as a case for containing an electronic component. Thus, assembling of a large current circuit using power system component can be simply executed with a low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded circuit board suitable for mounting a large current component such as a semiconductor power module or a power transistor.

[0002]

2. Description of the Related Art Conventionally, in an electric circuit having a power system component through which a large current flows, the connection between the components is performed by an electric wire. An example thereof is shown in FIG. In the figure, 1
Is a case made of a resin molded body, 3 is a large current component such as a semiconductor power module, 5 is a large current component such as a capacitor,
7 is an adhesive for fixing components, 9 is a printed circuit board for a control circuit, 11 is a connector, 13 is an electric wire for wiring, and 15 is a screw for tightening and connecting the electric wire 13 to a component terminal.

[0003]

In the conventional electric circuit having the power system parts, since the connection between the parts is performed by the electric wires, the wiring is troublesome and the automation of the assembly is difficult. In order to eliminate the wiring work, it is possible to use a large current circuit board similar to the printed circuit board used in the weak current circuit, but the terminals of the power system electronic parts are screwed connection method. Therefore, there has been a problem how to connect the terminal and the circuit conductor of the circuit board.

[0004]

SUMMARY OF THE INVENTION The present invention provides a molded circuit board suitable for mounting a large current component which solves the above problems, and has a structure formed in a predetermined circuit pattern. A stud (female screw or male screw) for screwing connection is fixed to one or both sides of the thick circuit conductor by welding, and the first resin molded body is integrally formed on one surface of the thick circuit conductor. And the second resin molded body is integrally formed on the other surface, and the thick circuit conductor exposes the head of the stud between the first resin molded body and the second resin molded body (preferably It is characterized in that it is embedded in a protruding state.

[0005]

According to the above construction, the thick circuit conductor formed in the predetermined circuit pattern is embedded in the resin molded body, and the head of the stud fixed to the thick circuit conductor is exposed on the surface of the resin molded body. Since an insulative circuit board can be obtained,
It is possible to easily assemble a large current circuit by screwing and connecting terminals of power system parts to the studs. Since the stud is fixed to the thick circuit conductor by welding, and the thick circuit conductor is embedded by the first resin molded body and the second resin molded body, the stud, the thick circuit conductor, and the thick circuit conductor. Since the resin molded body and the resin molded body are extremely strong, it is possible to make a strong and reliable screw connection.

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In this molded circuit board, a stud (female screw) 23 for screwing connection is fixed to one surface of a thick circuit conductor 21 formed in a predetermined circuit pattern by welding, and the stud fixing surface of the thick circuit conductor 21 is The first resin molded body 25 is integrally formed on the opposite surface, and the second resin molded body 27 is integrally formed on the stud fixing surface of the thick circuit conductor 21 to form the thick circuit conductor 21 One resin molded body 25 and second resin molded body 2
7 and the head portion of the stud 23 is projected from the surface of the second resin molded body 27. The first resin molded body 25 has a flat plate shape, but the second resin molded body 27 is formed in a box shape so that it can be used as a case for housing electronic components.

Next, a method of manufacturing this molded circuit board will be described with reference to FIGS. First thickness 0.2-2
A thick circuit conductor connecting pattern 2 having a shape as shown in FIG. 2, for example, by press punching, etching or water jet cutting from a copper plate or an aluminum plate of about mm.
9 is formed. This thick-walled circuit conductor connecting pattern 29 has a plurality of thick-walled circuit conductors 21 to be separated later, and a connecting portion 31.
Are connected while maintaining a predetermined positional relationship.

Next, as shown in FIG. 3, each thick circuit conductor 21 is formed.
The stud 23 is fixed to the predetermined position by welding. Next, the thick circuit conductor connecting pattern 29 with the stud 23
Is set in the first mold for resin molding, and the stud 2
As shown in FIG. 4, the surface opposite to the first resin molded body 2
5 is molded. PE, PBT as the resin material
(Polybutylene terephthalate), ABS resin, PPS
A thermosetting resin such as a thermoplastic resin or an epoxy resin is used. The thickness of the first resin molding 25 is about 3 to 4 mm. Since the arrangement of the plurality of thick-walled circuit conductors 21 is fixed by this, the connecting portion 31 is then cut by making a hole 33 in the connecting portion 31 as shown in FIG. As a result, a plurality of thick circuit conductors 21 are separated.

This manufacturing process is performed by separating a plurality of thick-walled circuit conductors from the beginning so that the thick-walled circuit conductors are individually placed at predetermined positions when molding the resin molded body. This is because it has to be set, which is troublesome, and the relative positions of the individual thick circuit conductors may shift during resin molding.

Next, the composite body of the thick-walled circuit conductor 21 and the first resin molding 25 shown in FIG. 5 is set in the second mold, and the surface on the side of the stud 23 is set as shown in FIG. The second resin molded body 27 is molded. This molding is performed so that the head of the stud 23 is not embedded. This completes the molded circuit board. FIG. 1 shows a cross section taken along line AA of the molded circuit board of FIG.
As is clear from FIG. 1, the holes 3 opened for cutting the connecting portion
3 is for molding the second resin molded body 27,
It is blocked by the resin.

When forming a hole for cutting the connecting portion, the shape of the hole is set to an appropriate character or symbol so that the first resin molded body and the second resin molded body have different colors. By doing so, it is possible to display characters or symbols without printing by filling the holes with resins of different colors. The first resin molded body 25 and the second resin molded body 27 are shown in FIG.
However, the first resin molded body 25 is formed on the surface of the thick circuit conductor 21 on the stud 23 side, and the second resin is formed on the opposite surface, as shown in FIG. It is also possible to form the molded body 27.

FIG. 8 shows a state in which the same components as in the case of FIG. 9 are mounted on the molded circuit board of the present invention. 9 and 1
The same reference numerals are given to the same portions as. The components 3 and 5 can be electrically connected by the thick circuit conductor 21 embedded in the resin moldings 25 and 27 only by fastening the terminals to the studs 23 with the screws 15. Also, the printed circuit board 9 can be electrically connected and mechanically attached at the same time by simply tightening the screw 15 to the stud 23. Therefore, the assembly is extremely simple and the assembly is easy to automate.

[0013]

As described above, according to the present invention, it is possible to obtain a molded circuit board on which power system components can be mounted by screwing, and wiring by electric wires is not required. Very easy to assemble the current circuit,
There is an advantage that it can be done at low cost. Further, since the studs for screwing are firmly integrated with the thick-walled circuit conductor and the resin molded body, highly reliable screwing connection can be performed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a large current molded circuit board according to the present invention.

FIG. 2 is a perspective view showing an example of a thick circuit conductor connection pattern used for manufacturing the large-current molded circuit board of the present invention.

FIG. 3 is a perspective view showing a state in which a stud is welded to the thick circuit conductor connection pattern of FIG.

FIG. 4 is a perspective view showing a composite body in which a first resin molded body is molded on one surface of the thick circuit conductor connecting pattern with studs of FIG.

5 is a perspective view showing a state in which a hole is formed in a thick circuit conductor connecting portion of the composite of FIG.

6 is a perspective view of a large-current molded circuit board obtained by integrally forming a second resin molded body on the perforated composite body of FIG.

FIG. 7 is a sectional view showing another embodiment of the large current molded circuit board according to the present invention.

FIG. 8 is a perspective view showing a state in which components are mounted on the large-current molded circuit board of the present invention.

FIG. 9 is a perspective view showing a structure of a conventional large current circuit.

[Explanation of symbols]

 21: thick-walled circuit conductor 23: stud 25: first resin molded body 27: second resin molded body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Yatabe 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (1)

[Claims] 1. A thick resin conductor formed in a predetermined circuit pattern has a stud for screwing connection fixed to one surface or both surfaces thereof by welding, and one surface of the thick circuit conductor has a first resin molded body. And a second resin molded body integrally formed on the other surface of the stud, and the thick circuit conductor is formed between the first resin molded body and the second resin molded body. A molded circuit board for large current, characterized in that it is embedded in an exposed state.