JPH08195535A - Wiring board - Google Patents

Abstract

PURPOSE: To alter the sectional area of a conductor without waste by laying an assembly of non-insulating conductor strands of small diameters as circuit conductors on an insulating base to form a circuit. CONSTITUTION: Circuit conductors 2 are bundled by a method such as previously lightly stranding, etc., evenly cut in the lengths, branched or molded and fixed to a simple jig, and mounted on an insulating board 3 coated with adhesive 4 in advance to be temporarily fixed with the viscosity of the adhesive. When all the conductors 2 are mounted, the entirety is pressed to adhesively fix the conductors 2 to the board 3. Then, in order to insulate and protect the surfaces of the conductors 2, an overlay film 5 in which the electric connecting point parts of the conductors 2 are cut out is coated with the adhesive, superposed on a laminate, and a circuit board 1 is formed by pressing. Thereafter, a connecting terminal 6 is mounted at the end connecting parts of the conductors 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board, which is used for distributing a relatively large current in a vehicle or in a general electric device, as an alternative to a wiring substrate such as a flat cable or a printed wiring board. .

[0002]

2. Description of the Related Art Conventionally, there have been the following methods for wiring in electric devices such as a device inside a vehicle, a machine tool, and a motor control drive circuit in which a relatively large current flows. The usual method is to wire cables, bus bars, etc. directly inside the device, or to attach wiring materials that have been wired into a wire harness by bundling the wires in advance. However, since the wiring passes through the space, it occupies a large wiring volume. Therefore, a method of using a printed wiring board can be considered. That is, a printed wiring board on which a circuit is formed by etching a copper foil laminated on the surface of an insulating base material is used to connect an electric circuit, which has the advantage of being easy to automate and enabling complicated wiring with a small wiring volume. Since it is difficult to etch the foil, it is difficult to form a high-current circuit, and the printed wiring board can be used only when the current is relatively small. Therefore, a large-current wiring board has been devised in which a conductor formed by cutting or punching a metal plate such as a copper plate into a required shape is provided on an insulating substrate. If a conductor plate having a large thickness is used for this large-current wiring board, a considerably large current can flow. FIG. 3 shows an example of a conventional high-current wiring board. A circuit conductor 2 formed by punching or cutting with a press from a copper plate is placed at a predetermined position on an insulating substrate 3 made of glass epoxy resin or paper phenolic resin, and fixed with an adhesive 4. The circuit conductor 2 and the insulating substrate 3 are adhered to each other by applying the adhesive 4 in advance to the entire surface of the insulating substrate 3 or the side of the circuit conductor 2 to be adhered, and then pressing, or an epoxy resin of B stage or the like. This is performed by sandwiching a sheet-shaped prepreg material in which glass fiber is impregnated with a semi-cured thermosetting resin between the circuit conductor 2 and the insulating substrate 3 and hot pressing the whole. Subsequently, the electrical connection portion of the insulating substrate 3 is cut out in advance and the overlay film 5 coated with the adhesive 4 is superposed on the laminate and laminated by pressing or heat pressing to electrically insulate the surface of the circuit conductor 2. In some cases, an insulating paint such as a solder resist may be printed or applied instead of the overlay film insulation and baked. A relay terminal for electrical connection is attached to the connection portion of the circuit conductor 2 by soldering or welding, and is electrically connected and fixed to an electrical connection member, a connection terminal or the like by a bolt or a screw. The large-current wiring board 1 manufactured in this manner has the features that not only a large current can flow, but also the wiring inside the device is easy and complicated wiring can be performed with a relatively small wiring volume.

[0003]

The circuit conductors 2 of this high-current wiring board are structurally made to have the same conductor width,
It is desirable to use thick conductors for large currents and thin conductors for small currents. However, if conductors with different thicknesses are used depending on the circuit, a step is generated on the conductor surface, and the circuit conductor 2 and the insulating substrate 3 Since it becomes difficult to apply uniform pressure to all the circuit conductors in the step of adhering and the step of adhering the overlay film 5, the thickness of the conductor cannot be changed depending on the circuit. In addition, since the terminals of the parts to be connected are often made at a constant pitch, it is often necessary to wire the circuit conductors 2 at a constant pitch. It is not possible to do this, and due to the difficulty of processing such as punching, it is not possible to manufacture circuit conductors with a very narrow width even with small current circuits. For these reasons, in a small current circuit, a circuit conductor having an unnecessarily large circuit cross section is often used, and there is a drawback that the weight of the circuit conductor 2 becomes larger than that required due to the current capacity.
Further, this high-current wiring board requires an expensive punching die for punching the circuit conductor 2. Therefore, even if a slight design change occurs in the wiring board 1, a large expense is required for changing the die, so that the wiring board can be freely designed. It was difficult to make changes. Further, when the circuit conductor 2 is punched or cut, a large metal material loss occurs, which makes the wiring board expensive. Further, since the circuit conductor 2 is manufactured by punching or cutting from a thick metal plate, complicated processing is difficult, and it is difficult to directly attach a general-purpose wire connecting terminal. The terminals for use must be connected by soldering or welding, which is disadvantageous in terms of economy and reliability of electrical connection. Depending on the intended use of the wiring board 1, it may be desired to bend a part of the wiring board at a right angle or the like, but since the circuit conductor 2 is hard, it is almost impossible to bend and use the wiring board.

[0004]

The present invention is a new wiring board which solves the drawbacks of the large current wiring board. That is, the present invention is a wiring board characterized in that a circuit is formed by laying an assembly of thin non-insulated conductor wires as a circuit conductor on an insulating substrate.

[0005]

In the wiring board of the present invention, since the conductor is a bundle of thin non-insulated conductor wires in a bundle, a circuit is used. Therefore, a predetermined number of wires are used for each circuit according to the current capacity. It has become possible to change the cross-sectional area of the conductor without waste. By laying loosely twisted bundles as an assembly of small-diameter strands, a large current circuit bundles a large number of strands, resulting in a large wire diameter and a step between the small current circuits. In the pressing process of adhering the circuit conductor and the insulating substrate, and also in the pressing process for laminating the overlay film, the large diameter circuit conductor is easily compressed and the apparent thickness becomes the same as the small diameter circuit conductor, which is smooth. Can be pressed into. Further, in the wiring board of the present invention, since the wiring board can be produced without unnecessarily increasing the cross-sectional area of the small current circuit, the waste of the material is eliminated and the weight of the wiring board can be reduced. Further, the cost of the material can be reduced because there is no loss of the expensive material as compared with the conventional large-current wiring board for punching a copper plate. Further, since the wiring board of the present invention does not require an expensive die for punching the circuit conductor, it is possible to freely change the design of the wiring board. Further, since the terminal of the circuit conductor of the wiring board of the present invention is an assembly of strands, a general-purpose wire connection fitting can be easily attached, which is economical and highly reliable in electrical connection. Further, since the circuit conductor of the wiring board of the present invention is an assembly of strands and is flexible, if a flexible insulating substrate is used, a part of the wiring board can be bent and used together with the conductor.

[0006]

EXAMPLES The present invention will be described in detail below with reference to examples. FIG. 1 illustrates the structure of the wiring board 1 of the present invention. Reference numeral 2 is a circuit conductor, which is a bundle of thin non-insulated conductor wires. The thickness of the conductor wire is not particularly limited, but if the wire diameter is too thick, the wire is hard and processing becomes difficult, and compression deformation is difficult unless a large pressure is applied even in the pressing step. Also, if the wire diameter is too small, not only the process of bundling a large number of wires becomes troublesome, but also the self-holding property of the wire bundle becomes poor and it becomes difficult to perform positioning on the insulating substrate with high accuracy. . The diameters of the large current circuit and the small current circuit can be changed, and it is desirable to select the diameter of the strands so that at least the minimum current circuit forms a bundle of two or more strands. Generally, when the wire is a copper wire, the wire diameter is 0.08 mm to 0.5 mm, and when the wire is an aluminum wire, the wire diameter is 0.2 mm to 1 mm. The reason why non-insulated conductor wires are used for the circuit conductor 2 is that if this is an assembly of insulated wires, not only is it necessary to peel off the insulating layers of the individual wires at the connection part of the terminal, This is because when the conductor is branched, inconvenience occurs in the flow of current. 3 is an insulating substrate, which is generally made of a material such as a glass epoxy plate or a paper phenolic plate that is used for a general-purpose printed circuit board. However, an inorganic insulating plate such as a thermoplastic resin plate or a ceramic is also used, and there is no particular limitation on the material. . Insulating substrate 3
There is no particular limitation on the thickness of the product. Generally, the thickness is about 1.6 mm.
The thickness is 2 if strength is required.
If the wiring substrate 1 is required to have flexibility, a thin material having a thickness of 0.1 mm is also used. Reference numeral 4 is an adhesive for fixing the circuit conductor 2 to the insulating substrate 3, which is applied on the surface of the insulating substrate 3 in advance before mounting the circuit conductor 2 on the insulating substrate 3, and the circuit conductor 2 is insulated by its viscosity. The circuit conductor 2 is temporarily fixed on the substrate 3, and then the circuit conductor 2 is fixed while being compressed by the press in the pressing step while being hardened by pressing. The adhesive 4 may be of any type as long as it has an appropriate viscosity at the time of temporary fixing, is then cured under appropriate conditions, and has a certain strength after curing. The circuit conductor 2 is lightly twisted in advance by wire bundle processing or the like, and the lengths are cut and aligned, or branching or molding is performed. Then, the circuit conductor 2 is fixed to a simple jig and the adhesive 4 is applied in advance. It is placed on the existing insulating substrate 3 and temporarily fixed by the viscosity of the adhesive. The branch points of the circuit conductor 2 are preferably fixed in advance with solder or adhesive or fixed with tape or the like. When mounting a plurality of circuits on one wiring board, it is desirable to prepare a plurality of jigs and mount them in order. When all the circuit conductors 2 have been placed on the insulating substrate 3, the whole is pressed to bond and fix the circuit conductors 2 to the insulating substrate 3. The pressure of the press may be such that the circuit conductor 2 having a large wire diameter is compressed and the surface of the conductor is flattened, and the circuit conductor 2 having a small wire diameter is also pressed against the insulating substrate 3 to achieve good adhesion. . At this time, heat may be applied to accelerate the curing of the adhesive 4. Next, an adhesive (not shown) is applied in advance to insulate and protect the surface of the circuit conductor 2, and the overlay film 5 in which the electrical connection points of the circuit conductor 2 are cut out is stacked on the laminated body and pressed. Also at this time, heat may be applied to promote adhesion of the overlay film 5. The overlay film 5 may be laminated at the same time as the pressing step for adhering the circuit conductor 2 to the insulating substrate 3. The cutout of the electrical connection point portion of the overlay film 5 may be performed after the step of laminating the overlay film 5. Further, instead of laminating the overlay film 5, an insulating paint such as a solder resist may be printed or applied to substitute the insulating paint. If a part of the wiring board 1 needs to be bent even after this, the wiring board 1 is bent by an appropriate method such as a bender or a press. Finally, the connection terminal 6 is attached to the terminal connection portion of the circuit conductor 2. Since the end of the circuit conductor 2 is almost the same as the end of an ordinary stranded wire, the connection terminal 6 used for connecting an ordinary electric wire is used as it is, and is attached to the end of the circuit conductor 2 by crimping with a caulking tool. .

[0007]

[Other Embodiments] FIG. 2 illustrates an example of a wiring board when circuits are crossed as another embodiment of the present invention. When the circuits intersect, the circuit conductors 2 are not intersected on the insulating substrate 3, and the jumper wire 7 or the like is used in the subsequent step after the overlay film 5 having the opening portion provided in advance at the connection portion is laminated. To connect. The jumper wire 7 uses an insulated wire with an ordinary wire connection terminal 6,
It does not necessarily have to be insulated. The jumper wire 7 is pre-drilled in an appropriate place on the wiring board 1,
It can also be passed through the back side of the wiring board 1. Jumper wire 7
The circuit conductor 2 is connected to the circuit conductor 2 by using a connection terminal 6 by an ordinary wire connection method such as caulking.

[0008]

According to the wiring board of the present invention, a circuit conductor having a small diameter corresponding to the current capacity can be used in the small current circuit.
It has become possible to reduce weight and cost. Further, according to the wiring board of the present invention, it is not necessary to use an expensive die for punching the circuit conductor, so that the design can be freely changed. Further, according to the wiring board of the present invention, since a general-purpose wire connection fitting can be used, it is economical and the reliability of electrical connection can be improved. Further, since the circuit conductor of the wiring board of the present invention is an assembly of strands and is flexible, it has become possible to bend a part of the wiring board together with the conductor for use.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a wiring board of the present invention.

FIG. 2 is an explanatory diagram showing another example of the wiring board of the present invention.

FIG. 3 is an explanatory diagram of a conventional high-current wiring board.

[Explanation of symbols]

 1 Wiring board 2 Circuit conductor 3 Insulating board 4 Adhesive 5 Overlay film 6 Connection terminal 7 Jumper wire

Claims (1)

[Claims] 1. A wiring board having a circuit formed by laying an assembly of at least a plurality of non-insulated conductor wires on an insulating board.