JPH07283546A - High breakdown-voltage large current wiring board - Google Patents

Abstract

PURPOSE:To provide a large current capacity by fixing a cylindrical conductor at a specific position of plate-shaped conductor for a large current for continuity in the thickness direction of a wiring board. CONSTITUTION:A cylindrical conductor 15 for continuity in the thickness direction of a wiring board is fixed at a specific position of a plate-shaped conductor 13. An insulation coating layer 17 is provided on the surfaces of the plate-shaped conductor 13 and the cylindrical conductor 15. The insulation coating layer 17 is provided excluding a part required for electrical connection with other conductors. Also, an insulation plate 19 which is not overlapped with the plate- shaped conductor 13 is laid out on the same layer as the plate-shaped conductor 13. Further, a plurality of layers constituted of the plate-shaped conductor 13 and the insulation plate 19 are provided and are laminated while holding an insulation film 21 between layers, thus preventing insulation property from being deteriorated even under a high voltage and achieving a high break-down voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board for carrying a large current, and a high breakdown voltage large current wiring board which can withstand a relatively high voltage.

[0002]

2. Description of the Related Art A wiring board used for a motor control circuit or the like requires not only a thin circuit conductor through which a small current for signals flows but also a thick circuit conductor through which a large current for power flows. Conventionally, as this type of wiring board, one in which a thick circuit conductor for large current is embedded inside an insulating substrate and a thin circuit conductor for small current is arranged on the surface of the insulating substrate has been put into practical use (actually, Kaihei 3-99469).

In this type of wiring board, a glass epoxy board is used as an insulating board, and a thin circuit conductor has a thickness of 35 mm.
~ 70μm copper foil, thick circuit conductor thickness 200
A copper plate of about 500 μm is used. A wiring board having a structure in which a thick circuit conductor for large current is embedded in an insulating substrate has excellent high-speed switching characteristics and high-frequency characteristics.

[0004]

However, in a high-current wiring board having a structure in which a thick circuit conductor is embedded inside an insulating substrate, defects such as voids may occur inside the insulating substrate when the thick circuit conductor becomes thicker. It has a drawback that it easily occurs. This is because, when a glass epoxy sheet and a thick circuit conductor are laminated and hot pressed, the glass epoxy sheet cannot fully fill the thickness of the thick circuit conductor in a region where the thick circuit conductor does not exist. by. Therefore, the conventional large current wiring board
The thickness of the thick circuit conductor is limited to about 500 μm, which limits the increase of current capacity.

Further, in the conventional large current wiring board, conduction in the thickness direction is obtained by through holes. Since the inner surface of the through hole is copper-plated, it is difficult to increase the plating thickness. Therefore, the conventional large-current wiring board is also limited in increasing the current capacity in the thickness direction.

Further, the conventional large-current wiring board uses a glass epoxy substrate as an insulating substrate, but the usable voltage of the glass epoxy substrate is generally set to 200 to 400 V, and if the voltage exceeds that, Insulation deterioration easily occurs and there is a problem in reliability.

In view of the above problems, an object of the present invention is to provide a high withstand voltage large current wiring board having a larger current capacity and higher withstand voltage than ever before.

[0008]

In order to achieve this object, the invention of claim 1 provides a tubular conductor for conducting in the thickness direction of the wiring board at a predetermined position of the plate conductor for large current. An insulating coating layer is provided on the surface of the plate-shaped conductor and the cylindrical conductor except for a portion necessary for electrical connection with other conductors, and the shape of the plate-shaped conductor does not overlap with the plate-shaped conductor. The insulating plate formed on the substrate is disposed, and a plurality of layers including such a plate-shaped conductor and the insulating plate are laminated, and an insulating film is sandwiched between the layers to laminate the layers.

The layer composed of the plate-shaped conductor and the insulating plate and the insulating film may or may not be adhered. If not adhered, the entire stack may be clamped by suitable clamping means to maintain integrity.

The invention of claim 2 is a combination of the high withstand voltage large current wiring board of claim 1 with a composite printed wiring board, wherein the composite printed wiring board has a thin-walled circuit conductor for a small current. Claims: A composite printed wiring board comprising: a thick circuit conductor for a large current; and a cylindrical protrusion penetrating the printed wiring board at a predetermined position on the thick circuit conductor. The high-voltage large-current wiring board described in 1 is arranged in parallel with a space, and the cylindrical projection of the composite printed wiring board and the cylindrical conductor of the high-voltage large-current wiring board are connected with their end faces abutted. It is characterized by having done.

[0011]

A high-voltage high-current wiring board according to the present invention, wherein insulation of the plate conductors in the same layer is secured by an insulating coating layer and an insulating plate, and insulation between layers is secured by an insulating coating layer and an insulating film. Is. Therefore, the thickness of the plate conductor is not limited, and it is possible to obtain a large current capacity by using a plate conductor having a large thickness. In addition, because an insulating film is placed between the layers,
Even if a high voltage is applied, there is no fear that the insulation will deteriorate, and a high withstand voltage can be guaranteed.

Further, according to the invention of claim 2, since the composite printed wiring board having a thin circuit conductor for a small current is combined with the high-voltage high-current wiring board of claim 1 with a space therebetween, The small voltage current circuit is less likely to be affected by the high voltage high current circuit. In addition, since the cylindrical projection of the composite printed wiring board and the cylindrical conductor of the high-voltage high-current wiring board are connected with their end faces abutted, both wiring boards can be easily connected and assembled. Easy to do.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings.

[Embodiment 1] FIGS. 1 and 2 show an embodiment of the present invention. This high voltage large current wiring board 11
A plate-shaped conductor 13 made of a copper plate (oxygen-free copper, tough pitch copper, etc.) having a thickness of about 1 to 3 mm is provided. The plate-shaped conductor 13 is a copper plate formed into a desired circuit pattern by press punching, water jet cutting, or the like.

At a predetermined position of the plate-shaped conductor 13, a cylindrical conductor 15 is fixed for conducting in the thickness direction of the wiring board.
As shown in FIG. 2, the tubular conductor 15 has a constant inner diameter and a stepped outer diameter. One end is a large diameter portion 15a and the other end is a small diameter portion 15.
It is b. To fix the tubular conductor 15 to the plate conductor 13, the small diameter portion 15a of the tubular conductor 15 is inserted into the hole formed in the plate conductor 13.
, And the plate-shaped conductor 13 around the small-diameter portion 15a in that state.
The small diameter portion 15a and the plate conductor 13 may be welded or brazed. The tubular conductor 13 can be manufactured by cutting, cutting or press-forming a copper tube.

An insulating coating layer 17 is provided on the surfaces of the plate-shaped conductor 13 and the tubular conductor 15 as shown in FIG. The insulating coating layer 17 is provided excluding portions (upper end surface and lower end surface of the tubular conductor 15 in the illustrated example) required for electrical connection with other conductors. The insulating coating layer 17 can be formed by powder coating of resin. The insulating coating layer 17 has a thickness of about 200 μm, and the material thereof is, for example, epoxy resin.

In the same layer as the plate conductor 13, the plate conductor 13
An insulating plate 19 having a shape that does not overlap with is arranged. Insulation plate 19
Is formed by cutting the shape of the plate-shaped conductor 13 from a glass epoxy plate, a paper phenol plate, an ABS resin plate or the like by router processing. The thickness of the insulating plate 19 is a plate-shaped conductor.
The total thickness is 13 and the insulating coating layer 17 on both sides thereof.

In the example of FIG. 1, four layers are formed by the plate-shaped conductor 13 and the insulating plate 19, and these layers are laminated with the insulating film 21 sandwiched between the layers. Insulation film
It is desirable to use a PET (polyethylene terephthalate) film as 21, but it is also possible to use a mica film or a polyethylene film.

It is desirable that the insulating film 21 be coated with an epoxy adhesive on both sides thereof to adhere to the layer composed of the plate conductor 13 and the insulating plate 19. However, insulating film 21
The plate conductor 13 and the layer formed of the insulating plate 19 do not necessarily have to be adhered to each other, and the entire laminated body may be tightened with an appropriate tightening member such as a bolt and nut. Further, if the laminated state can be maintained by other means, the tightening member is unnecessary. The cylindrical conductor 15 of the insulating plate 19 and the insulating film 21 is
For the convenience of stacking and mounting of parts,
Of course, it is formed.

The above is the structure of the high withstand voltage large current wiring board 11 of this embodiment. This high-voltage high-current wiring board 11 is a plate-shaped conductor 13
Since the thickness of the plate-shaped conductor 13 can be sufficiently filled by setting the thickness of the insulating plate 19 according to the thickness of the plate-shaped conductor 13, the thickness of the plate-shaped conductor 13 is arbitrarily determined according to the required current capacity. be able to. Therefore, it is possible to obtain a wiring board having a large current capacity using a thick plate conductor having a thickness of about 1 to 3 mm. As a result, it is possible to energize up to about 500 A with one layer of plate-shaped conductor. Also, conduction in the thickness direction of the wiring board is a cylindrical conductor.
Although obtained by 15, the cross-sectional area of the tubular conductor 15 can be arbitrarily selected, so that the current capacity in the thickness direction can be made sufficiently large. For example, if the outer diameter of the tubular conductor 15 is 13
With a diameter of mmφ and an inner diameter of 7 mmφ, about 370 A can be energized.

Regarding the breakdown voltage between layers, the insulating film
When PET film is used as 21, the thickness is 250 μm.
A breakdown voltage of 75kV is obtained, and in addition to this, an insulating coating layer
17 is a powder coating with a thickness of 200 μm and a withstand voltage of 6 kV can be obtained.
Insulation in the same layer can be sufficiently secured by the insulating coating layer 17 and the insulating plate 19. Therefore, a wiring board having an extremely high withstand voltage can be obtained.

FIG. 1 shows a state in which a power component 25 such as an IGBT (insulated gate transistor) or a diode is mounted on the high withstand voltage large current wiring board 11 as described above. 27
Is a screw for connecting the power component 25 to the tubular conductor 15. Since the power component 25 generates heat, it is fixed to the aluminum block 29 for heat sink. The power component 25 fixed to the aluminum block 29 has a difference in height, and this difference can be absorbed by adjusting the length of the tubular conductor 15.

[Embodiment 2] FIGS. 3 and 4 show another embodiment of the present invention. This high withstand voltage large current wiring board 11 is different from the wiring board of the first embodiment in that the small diameter portion 15 of the tubular conductor 15 is
The length of b is increased so that the upper end surface of the cylindrical conductor 15 is substantially flush with the same plane. This way the screws
Since 27 tightening operations can be performed at the same height, assembly becomes easy. Since the other configurations are the same as those in the first embodiment, the same parts are designated by the same reference numerals and the description thereof will be omitted.

[Embodiment 3] FIG. 5 shows an embodiment of the present invention. This wiring board is a combination of a high-voltage large-current wiring board 11 similar to that of the second embodiment and a composite printed wiring board 31. In the high withstand voltage large current wiring board 11, the small diameter portion 15b of the tubular conductor 15 is lengthened so that the upper end surface of the tubular conductor 15 is flush with the same plane. Further, an insulating plate 19 is further laminated under a layer composed of the lowermost plate-shaped conductor 13 and the insulating plate 19 via an insulating film 21 to enhance the insulating property.

On the other hand, the composite printed wiring board 31 is an insulating substrate.
Cylindrical shape in which a thick circuit conductor 37 for large current is provided on a printed wiring board in which a thin circuit conductor 35 for small current is formed on both sides of 33, and the printed circuit board is penetrated at a predetermined position of the thick circuit conductor 37. The protrusion 39 is formed. The thin circuit conductor 35 is thick
The thick circuit conductor 37 is made of a copper foil having a thickness of about 35 to 70 μm, and the thick circuit conductor 37 is made of a copper plate having a thickness of about 1 to 3 mm. The cylindrical protrusion 39 is formed by burring (squeezing) the thick circuit conductor 37. Such a composite printed wiring board 31 is disclosed in JP-A-63-23749.
It is known from Japanese Patent No. 5 publication.

The cylindrical protrusion 39 of the composite printed wiring board 31 is
It is formed at the same position as the cylindrical conductor 15 of the high withstand voltage large current wiring board 11. Composite printed wiring board 31 and high-voltage high-current wiring board
11 is assembled by tightening a screw 27 in a state where the end surface of the cylindrical protruding portion 39 and the end surface of the cylindrical conductor 15 are abutted against each other. With this structure, the high withstand voltage large current wiring board 11
In addition, the composite printed wiring board 31 having the thin-walled circuit conductor 35 and the thick-walled circuit conductor 37 can be easily combined, and the electronic parts for the signal circuit can be mounted, so that the function as the wiring board can be enhanced. .

[0027]

As described above, according to the invention of claim 1, it is possible to use a plate-shaped conductor having a thicker plate thickness than before, and to use a cylindrical conductor having a large conductor cross-sectional area in the thickness direction of the wiring board. Therefore, the current capacity of the wiring board can be significantly increased. Further, the interlayer insulation is ensured by the insulation coating layer and the insulation film, and the insulation in the same layer is ensured by the insulation coating layer and the insulation plate, so that the withstand voltage of the wiring board can be greatly increased. Therefore, a wiring board having a large current capacity and a high withstand voltage can be obtained.

According to the second aspect of the present invention, it is possible to obtain a composite wiring board in which a low-voltage small-current circuit is unlikely to be affected by a high-voltage large-current circuit and which is easy to assemble.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a high withstand voltage large current wiring board according to the invention of claim 1.

FIG. 2 is a partially cutaway perspective view showing a connecting portion between a plate conductor and a tubular conductor in the wiring board of FIG.

FIG. 3 is a sectional view showing another embodiment of the high withstand voltage large current wiring board of the invention of claim 1;

4 is a partially cutaway perspective view showing a connecting portion between a plate conductor and a tubular conductor in the wiring board of FIG.

FIG. 5 is a sectional view showing an embodiment of the composite high withstand voltage large current wiring board of the invention of claim 2;

[Explanation of symbols]

 11: High-voltage high-current wiring board 13: Plate conductor 15: Cylindrical conductor 17: Insulation coating layer 19: Insulation plate 21: Insulation film 25: Power component 29: Aluminum block 31: Composite printed wiring board 33: Insulation board 35 : Thin-walled circuit conductor 37: Thick-walled circuit conductor 39: Cylindrical protrusion

Front page continuation (72) Inventor Somasa Jimbo 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (2)

[Claims] 1. A plate-shaped conductor (13) and a tube-shaped conductor (13) for fixing a tube-shaped conductor (15) for conducting in the thickness direction of a wiring board at a predetermined position of the plate-shaped conductor (13) for large current. An insulating coating layer (17) is provided on the surface of the conductor (15) except for a portion necessary for electrical connection with another conductor, and the plate conductor is formed on the same layer as the plate conductor (13).
Arrange the insulating plate (19) formed so that it does not overlap with (13),
A high withstand voltage large current wiring board, comprising a plurality of layers composed of such a plate-shaped conductor (13) and an insulating plate (19), and an insulating film (21) sandwiched between the layers. 2. A thick circuit conductor (37) for a large current is provided on a printed wiring board having a thin circuit conductor (35) for a small current, and printed at a predetermined position on the thick circuit conductor (37). A composite printed wiring board (31) having a cylindrical projection (39) penetrating the wiring board, and a high voltage and large current wiring board (11) according to claim 1.
And are placed in parallel with a space, and the composite printed wiring board (3
Composite high-voltage large-current wiring characterized in that the cylindrical protrusion (39) of 1) and the cylindrical conductor (15) of the high-voltage large-current wiring board (11) are connected with their end faces abutted. Board.