JP2000324657A - Printed circuit board and electrical junction box accommodating circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a printed circuit board which is accommodated in an electrical junction box, easily and at a low cost. SOLUTION: Rectangular bus bars 14, 15 are disposed at the upper and lower surfaces of an insulated sheet 11 in X- and Y-directions and cross-disposed via the insulated sheet. At a portion conducted in an intersection area, the insulated sheet is formed with an opening 25, through which upper and lower bus bars are resistance-welded for conduction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board and an electric connection box provided with the circuit board, and more particularly, to an electric connection box in which a bus bar is used as an internal circuit. It can be easily formed without punching.

[0002]

2. Description of the Related Art Conventionally, as a circuit board constituting an internal circuit of an electric junction box such as a junction box for an automobile, an electric wire such as a single-core wire is laid along an electric circuit on an insulating plate. There is a case where a press contact method in which a press contact terminal is driven into the circuit and a press contact is used, or a bus bar formed by punching a conductive metal plate into a circuit shape using a mold is used.

[0003]

In the case where the pressure welding method is used for the configuration of the internal circuit, recently, the number of circuits to be accommodated in the electric connection box has been rapidly increasing due to the rapid increase of the electrical components, and the insulation for wiring the electric wires has been increasing. Since the shape of the plate is complicated, it takes time to wire the wires and process the insulating plate, and there is a problem that the manufacturing cost increases.

Further, when a bus bar is used as an internal circuit, a punching die must be manufactured according to the circuit, so that it is not possible to easily cope with a circuit change, and it is costly to manufacture the die. There is. In addition, there are many portions that are not used after the punching process, and the yield of the conductive metal plate as a material is poor, which causes an increase in cost. Furthermore, due to the rapid increase of circuits accommodated in the electric junction box, 7 to 8 bus bars in the horizontal direction must be stacked and arranged in a large number of layers with an insulating plate interposed therebetween, and the cost tends to be enormous. .

To solve the above problem, Japanese Patent Application Laid-Open No. 56-13 / 1981
Japanese Patent Application Publication No. 0989 proposes a circuit board 2 housed inside an electric junction box shown in FIGS. 10 (A) and 10 (B).
Insulating sheets 1a and 1b are laminated on both sides of a conductive member 3 formed by punching out a punched portion 3a of a conductive metal plate into a lattice shape. Wires are connected to the surroundings to connect to external circuits.

With the above configuration, the circuit is formed by cutting the unnecessary portion 3b, so that it is easy to cope with circuit change. However, a lattice circuit is formed by punching, and the punched portion 3a is formed. Since there are many locations, there is a problem that the yield of the conductive metal plate is not improved.

[0007] The present invention has been made in view of the above problems, and has as its object to reduce the cost of forming an internal circuit in an electric junction box. Also,
Second, it is an object to make it possible to easily cope with a change in a circuit. Third, it is another object to reduce the cost by easily forming an insulating material interposed between the bus bars.

[0008]

In order to solve the above problems, the present invention firstly provides a strip-shaped bus bar having a thickness of 0.1 mm.
05mm-0.4mm Insulating sheet is arranged in parallel in the X direction on one of the upper and lower surfaces, and Y on the other upper or lower surface.
Side by side, and cross-arranged through the insulating sheet,
An opening is provided in the insulating sheet at a place where conduction is made at the intersection where the cross is arranged, and at least one of the conducting busbars has a small protrusion slightly larger than the thickness of the insulation sheet or a circle having a large curvature. A circuit board is provided in which an arc-shaped bulging portion is provided, which is brought into contact with the other bus bar through an opening of the insulating sheet, and the contact portion of the bus bar is electrically connected by resistance welding.

As described above, by forming the conductive material from the strip-shaped bus bar, the material can be shared, and the material yield is improved without waste. further,
Conventionally, a punching process using a mold used for forming a bus bar becomes unnecessary, and the cost for forming a circuit can be significantly reduced.

As the insulating material interposed between the bus bars, an insulating material formed by resin molding with a metal mold is conventionally used. However, in the present invention, as described above, a thickness of 0.05 mm or more is used.
A 0.4 mm insulating sheet is used, and by using such a thin insulating sheet, the bus bar connected through the opening of the insulating sheet can be provided with small projections or arc portions by press working instead of die forming. It is possible to reduce the cost of forming the bus bar. Also, the insulating material is not an insulating plate to be molded, but an insulating sheet may be used and the opening may be provided by a punched hole, so that the cost of forming the insulating sheet can be reduced.

[0011] The present invention is, secondly, a thickness of 0.05 mm
A 0.3 mm strip-shaped busbar with a thickness of 0.05 mm
A 0.4 mm insulating sheet is juxtaposed in the X direction on one of the upper and lower surfaces, and juxtaposed in the Y direction on the other upper or lower surface. In a portion where conduction is provided in the portion, an opening is provided in the insulating sheet, resistance welding is performed by opposing bus bars to be conducted to both sides of the opening, and the opposing bus bars are deformed and brought into contact with the pressing force of the electrode during the resistance welding. A circuit board characterized by being conductive is provided.

In the second aspect of the present invention, the busbar is very thin, having a thickness of 0.05 mm to 0.3 mm, so that the busbar can be deformed by being bent by the pressure of the electrode during resistance welding. Therefore, the bus bar is not provided with the small projections or the arc-shaped projections as in the first invention by pressing, and the upper and lower bus bars are deformed and brought into contact during resistance welding to achieve conduction. As described above, when a thin plate that is easily deformed is used as the bus bar, it is not necessary to perform press working for providing a small projection or the like for welding on the bus bar, and the bus bar can be easily provided, and further, the bus bar forming cost is reduced. Can be lowered.

It is preferable that upper and lower bus bars welded through the opening of the insulating sheet are provided with an insulating coating for preventing short circuit. Specifically, after the upper and lower bus bars are welded through the opening of the insulating sheet, a quick-drying gel-like insulating agent is applied to the surface of the bus bar, or an insulating film is fused. As described above, when the insulating coating is provided on the surface of the bus bar, it is possible to prevent a short circuit from occurring in the adjacent bus bar even if there is moisture.

In both the first and second aspects of the invention, bus bars are simply provided side by side on the insulating sheet at intervals, but since there are many locations to be welded through openings in the insulating sheet, these It can be positioned and held at a predetermined position on the insulating sheet by welding. Further, in a state in which the bus bar and the insulating sheet are incorporated in the electric connection box, the bus bar and the insulating sheet are positioned and held on the electric connection box side, so that the bus bar is securely fixed to a predetermined position of the insulating sheet.

The X-direction bus bar and the Y-direction bus bar form necessary circuits by cutting unnecessary portions on the circuit. With this configuration, fixed-size strips can be used for the bus bars in the X direction and the Y direction, and the bus bars can be shared and cost can be reduced.

The strip-shaped bus bars arranged in parallel in the X and Y directions correspond to the pitch of the parallel arrangement with the terminal hole pitch of the fuse, relay and connector. For example, a part of the bus bars arranged in parallel in the vertical direction corresponds to the pitch of the fuse, the remaining bus bars in the vertical direction correspond to the pitch of the relay, and a part of the bus bars arranged in the horizontal direction corresponds to a small connector terminal hole. It corresponds to the pitch, partly corresponds to the medium pitch, and the rest corresponds to the large pitch. As described above, if the pitch of the bus bars arranged in the cross direction in the X and Y directions is made to correspond to the pitch of the terminal holes of the fuse, the relay, and the connector, the tab provided at the other end of the terminal plate connected to these bus bars is provided. Can be directly connected to fuses, relays and connectors.

Further, the present invention provides an electric junction box containing the above circuit board. In the electric junction box, the circuit board having the above-described configuration may be arranged in a single layer, or a plurality of the circuit boards may be arranged in a stacked manner via an insulating plate.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show a circuit board 10 according to the present invention, in which strip-shaped bus bars 14 are juxtaposed on an upper surface of an insulating sheet 11 having a thickness of 0.05 mm to 0.4 mm at intervals in the X direction. Strip-shaped bus bars 15 are juxtaposed on the lower surface of the insulating sheet 11 at intervals in the Y direction. The bus bars 14 in the X direction and the bus bars 15 in the Y direction are crossed via the insulating sheet 11 so as to form a grid. Have been placed.

A plurality of bus bars 14 arranged in the X direction
As shown in FIG. 2, both ends in the length direction
A and 16B are connected to each other, and are arranged on the upper surface of the insulating sheet 11 in this state. The width of the bus bar 14 is 2
mm, and the thickness is 0.64 mm. The bus bars 14 in the X direction have a portion arranged in parallel at a pitch of 4 mm,
A portion is provided at a pitch of 6.8 mm from the pitch, and is matched with the terminal pitch of the connector, fuse, and relay.

The same applies to the plurality of bus bars 15 arranged in the Y direction. As shown in FIG.
7A and 17B, and are arranged on the lower surface of the insulating sheet 10 in this state. Bus bar 15 is also 2m
The width is m, the thickness is 0.65 mm, and the pitch is 4 mm.

Small projections 20 higher than the thickness (0.05 mm to 0.4 mm) of the insulating sheet 11 are formed on the bus bar 14 in the X direction arranged on the upper surface by press molding toward a required portion downward. ing. In addition, instead of the small protrusion 20,
As shown in FIG. 7, an arc-shaped bulged portion 20 'having a low height may be provided by press working. The small projection 20 is located at the intersection with the bus bar 15 in the Y direction disposed on the lower surface, and is a portion where the bus bars 14 and 15 are desired to be conducted.

The bus bar 14 is cut away from the hatched portion 21 in FIG. 2 to leave only necessary circuit portions. Further, both ends A of the bus bar 14 in the longitudinal direction are cut off.
To form a terminal portion 22 protruding from the bus bar 14.

On the other hand, the bus bar 15 in the Y direction disposed on the lower surface side of the insulating sheet 11 has no small projection. Also in the bus bar 15, a portion 23 indicated by oblique lines in FIG. 3 is cut off to leave only necessary circuits, and furthermore, a terminal protruding from the bus bar 15 is bent downward at one end B in the length direction of the bus bar 15. A portion (tab) 24 is formed.

The insulating sheet 11 is made of a rigid insulating resin sheet having a thickness of 0.05 mm to 0.4 mm as described above. Bus bar 14 and bus bar 15
The opening 25 is formed by punching at the position where the crossing is made and the position where electrical conduction is desired to be achieved, because the wall is thin as described above. Through the opening 25, the tip of the small projection 20 of the upper bus bar 14 is brought into point contact with the plane of the lower bus bar 15.

As described above, the opening 25 of the insulating sheet 11
The small projections 20 of the bus bar 14 and the bus bar 15 which are brought into surface contact with each other are subjected to resistance welding using a resistance welding machine. That is, the upper electrode of the resistance welder is brought into contact with the small projection 20 and the lower electrode is brought into contact with the bus bar 15.
At this time, since the small projections 20 make point contact with the bus bar 15, heat is easily generated during resistance welding, and the weldability can be improved.

As described above, the bus bars 14 and 15 disposed on the upper and lower surfaces of the insulating sheet 11 are welded at required locations, so that conduction between the bus bars 14 and 15 can be achieved at required locations. In addition, since the conductive portion is welded by bringing the bus bars 14 and 15 into planar contact with each other, the connection reliability can be improved. Further, since the bus bars 14 and 15 are welded and connected at many places with the insulating sheet 11 interposed therebetween,
Although the busbars 14 and 15 are only arranged along the upper and lower surfaces of the insulating sheet 11, they are positioned at predetermined locations.

The upper and lower bus bars 14, 1 on the insulating sheet 11
The terminal portions 22 and 24 that are provided by bending the edge of the insulating sheet 5 are located at positions protruding from the edge of the insulating sheet 10, respectively, facing upward,
It protrudes downward.

The circuit board 10 formed as described above is shown in FIG.
As shown in (1), it is housed in the lower case 31 of the electric connection box, and assembled with the upper case 32 covered. Note that the circuit boards 10 may be stacked and arranged via an insulating sheet.

FIGS. 8A and 8B show a second embodiment.
Busbars 14, 1 arranged on both upper and lower surfaces of the insulating sheet 11
5 is an extremely thin one having a thickness of 0.05 mm to 0.3 mm. Since the bus bars 14 and 15 are made extremely thin in this way, they can be bent by the pressing force of the electrodes during resistance welding, and the insulating sheet also has a thickness of 0.05 mm to 0.4 mm.
mm, the bus bars 14 and 15 facing each other across the opening 25 of the insulating sheet 11 can be brought into contact with each other. Therefore, the small projections provided in the first embodiment are not provided on the bus bar 14 of the second embodiment, and the press work for providing the small projections is unnecessary.

That is, as shown in FIG. 8B, when the bus bar 14 is pressurized by the upper electrode 40 and the bus bar 15 is pressed by the lower electrode 41 of the resistance welding machine, the bus bars 14 and 15 bend in the directions approaching each other. When deformed, the bus bars 14 and 15 come into contact in the opening 25 and are resistance-welded. Other configurations are the first
The description is omitted because it is the same as the embodiment.

As described above, if the bus bars 14 and 15 are made extremely thin, it is not necessary to provide small projections in advance by press working for welding, and therefore, when the current capacity may be small. Is preferably used.

FIG. 9 shows a third embodiment, in which an insulating sheet 1 is used.
After resistance-welding the bus bars 14 and 15 through the opening 25, a quick-drying gel-like insulating material is applied to the surfaces of the bus bars 14 and 15 to provide an insulating coating 50. In addition, as an insulating material, an insulating film is
5 may be fused. Thus, the bus bar 1
When the surfaces of 4 and 15 are covered with the insulating coating 50, the insulating sheet 1
Even when the adjacent bus bars 14 or the bus bars 15 arranged at intervals on the surface of the first unit 1 are wet, short circuit can be prevented from occurring.

[0033]

As is apparent from the above description, according to the present invention, strip-shaped bus bars are arranged in a grid pattern on the upper and lower surfaces of a thin insulating sheet as an internal circuit of the electric connection box, and conduction at intersections is performed. In the portion to be formed, a punched opening is provided in the insulating sheet, and the upper and lower busbars are resistance-welded through the opening, so that conduction between the upper and lower busbars can be reliably and easily achieved. In addition, since the welding is performed using a resistance welding machine, automatic welding can be easily performed, and stable welding can be performed. As a result, electrical connection reliability can be improved.

Further, since a thin insulating sheet is used as the insulating material, the opening provided in the insulating sheet can be formed by punching instead of die molding, so that the manufacturing cost of the insulating material can be reduced. In addition, since the upper and lower bus bars are welded through the opening of the thin insulating sheet, the small projections provided on the bus bar can be formed by press working, and need not be formed by a mold, so that the cost can be reduced from this point as well. In particular, when a thin and easily deformable bus bar is used, it is not necessary to provide even a small projection, and the cost can be further reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a circuit board according to a first embodiment of the present invention.

FIG. 2 is a plan view of a bus bar arranged in an X direction.

FIG. 3 is a plan view of a bus bar arranged in a Y direction.

4A is a sectional view taken along line AA of FIG. 1, and FIG. 4B is a sectional view taken along line BB of FIG.

FIG. 5 is an enlarged sectional view of a main part.

FIG. 6 is a sectional view of a state where the circuit board is housed in an electric junction box.

FIG. 7 is an enlarged sectional view of a main part showing a modification of the first embodiment.

FIGS. 8A and 8B are enlarged cross-sectional views of a main part of the second embodiment.

FIG. 9 is a sectional view of a main part of a third embodiment.

FIGS. 10A and 10B are diagrams showing a conventional example.

[Explanation of symbols]

 Reference Signs List 10 circuit board 11 insulating sheet 14 busbar in X direction 15 busbar in Y direction 20 small protrusion 25 opening 40 upper electrode 41 lower electrode 50 insulating coating

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (4)

[Claims] 1. A strip-shaped bus bar having a thickness of 0.05 mm
X on either upper or lower surface of insulating sheet
Are arranged side by side in the Y direction on one of the upper and lower surfaces, and are arranged crosswise via the insulating sheet. At the portion where the crossing is conducted at the intersection, the opening is provided in the insulating sheet. At the same time, a small protrusion slightly larger than the thickness of the insulating sheet or an arc-shaped bulging portion having a large curvature is provided on at least one of the conductive bus bars, and the bus bar is brought into contact with the other bus bar through the opening of the insulating sheet. A circuit board, wherein a contact portion of a bus bar is electrically connected by resistance welding. 2. A strip-shaped bus bar having a thickness of 0.05 mm to 0.3 mm is arranged in parallel with one of the upper and lower surfaces of an insulating sheet having a thickness of 0.05 mm to 0.4 mm in the X direction. An opening is provided in the insulating sheet at a place where the conductive material is provided at the intersection where the cloth is arranged, and the bus bar is provided on both sides of the opening. A circuit board characterized in that the opposed bus bars are deformed and brought into contact with each other by the pressing force of the electrodes during the resistance welding to conduct electricity. 3. The circuit board according to claim 1, wherein upper and lower bus bars welded through openings in the insulating sheet are provided with insulating coatings for preventing short circuits. 4. An electric junction box containing the circuit board according to claim 1.