JP2000307202A - Circuit board and electric connection box accommodating the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to simply form a circuit board to be accommodated in an electric connection box at a low cost. SOLUTION: In a circuit board 10, strip-shaped bus bars 14, 15 are buried in bus bar trenches 12 in an X direction which are formed in parallel on either one of the upper and lower surfaces of an insulating plate 11, buried in bus bar trenches 13 in a Y direction which are formed in parallel on either one of the other upper and lower surfaces and arranged crosswise interposing an insulating plate. In an electrically continuous part in the intersection of the crosswise arrangement, an aperture 25 is formed on the insulating plate. A trapezoidal or a circular arc type bending part 20 is formed on at least one out of the bus bars which are made electrically continuous and brought into contact with the other bus bar via the aperture of the insulating plate. The contacts of the bus bars are resistance-welded and electrically connected.

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.

The present invention has been made in view of the above-described problems, and has as its first object to reduce the cost of forming an internal circuit in an electric junction box. Also,
A second object is to be able to easily respond to changes in the internal circuit.

[0008]

In order to solve the above-mentioned problems, according to the present invention, first, a strip-shaped bus bar is buried in an X-direction bus bar groove formed parallel to one of the upper and lower surfaces of an insulating plate. At the same time, the insulating plate is buried in a bus bar groove in the Y direction formed in parallel with the other upper or lower surface, and is arranged crosswise via an insulating plate. At the same time, at least one of the conductive bus bars is provided with a trapezoidal or arcuate bent portion, the bent portion is brought into contact with the other bus bar through the opening of the insulating plate, and the contact portions of these bus bars are resistance-welded. A circuit board characterized by being conductive is provided.

When the conductive material is formed of a strip-shaped bus bar, the material can be used in common, and the material yield is improved without waste. Furthermore, the punching process using a mold conventionally used for forming the bus bar is not required, and the cost for forming the circuit can be significantly reduced.

As described above, the bent portion of the bus bar
It may be formed on only one of the bus bars to be conducted, or may be formed on both bus bars, and the valleys of the bent portions may be brought into contact with each other to perform resistance welding. By forming the bent part on both sides, the depth of the bent part can be reduced,
Bending is easy, but both busbars must be bent, which is troublesome and has advantages and disadvantages. In addition, the bus bar material is easily stretched (plastic working is easy)
When the material is made of a material, the bent shape is the trapezoidal shape. On the other hand, when the bus bar material is made of a material that is hardly stretched (plastic deformation is difficult), the bent shape is preferably an arc shape.

The bent portion of the bus bar has a depth of 0.3
It is preferably in the range of 8 mm to 8 mm. 0.3mm
The reason for the above is that it is difficult to make the thickness of the insulating plate interposed between the bus bars smaller than 0.3 mm with the current resin molding technology if the thickness is smaller than 0.3 mm. Further, the reason why the length is set to 8 mm or less is that if it exceeds 8 mm, the electrode for resistance welding must be lengthened, and when a general-purpose resistance welding machine is used, 8 mm is the limit.

It is preferable that a small projection is provided on one of the contact surfaces of the bus bar which abut each other. The small projection may be provided to protrude from a valley of the bent portion, or may be provided to be protruded from a flat bus bar of the other party with which the bent portion comes into contact.

The bus bar is formed of a copper-based material or a brass-based material having high conductivity. However, since the bus bar has high conductivity, heat is hardly generated at the time of resistance welding, so that the weldability may be poor. Therefore, when the small protrusion is provided in the contact portion as described above, the contact point of the contact point of the X bus bar and the Y bus bar is changed from the surface contact to the point contact, and the weldability can be improved.

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 busbars arranged in parallel in the X direction and the Y direction have a pitch of the fuses,
It corresponds to the terminal hole pitch of relays and connectors. 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.

[0017]

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 an X-direction bus bar groove 12 is recessed in parallel on the upper surface of an insulating plate 11 and a Y-direction bus bar groove 13 is recessed in parallel on the lower surface. I have. These busbar grooves 1 in the X and Y directions
Strip bus bars 14 and 15 are buried and arranged in 2 and 13, respectively, and the bus bars 14 in the X direction and the bus bars 15 in the Y direction are cross-arranged via the insulating plate 11 so as to form a lattice. ing.

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 in this state, they are fitted into the bus bar grooves 12 of the insulating plate 11. The busbars 14 may be separated from the carriers 16A and 16B and fitted into the busbar grooves 12 in a state where the busbars 14 are separated one by one. Busbar groove 12 in the state
It is preferable that the carriers 16A and 16B be separated after fitting. Specifically, 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 busbars 15 arranged in the Y direction. As shown in FIG.
7A and 17B, and are fitted in the busbar grooves 13 of the insulating plate 10 in this state.
7A and 17B are separated. Specifically, the bus bar 15 is also 2 mm wide, 0.65 mm thick and 4 mm thick.
They are arranged at the pitch.

The X-direction bus bar 14 disposed on the upper surface
Has a bent portion 20 which is bent downward in a trapezoidal shape at a required location. The bent portion 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 depth h of the bent through portion 20 is 0.3 mm to 8 mm.

The bus bar 14 is cut off at a hatched portion 21 in FIG. 2 to leave only required 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 bent portion is not provided on the bus bar 15 in the Y direction disposed on the lower surface side of the insulating plate 11. 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 plate 11 has a bent portion 2 provided on the bus bar 14 at the bottom of the bus bar groove 12 in the X direction.
An opening 25 is provided in advance at a location facing 0 and molded. Therefore, the opening 25 is located at the position where the bus bar 14 and the bus bar 15 intersect and where conduction is desired,
Through the opening 25, the bent portion 20 of the upper bus bar 14 comes into surface contact with the plane of the lower bus bar 15. The depths of the bus bar grooves 12 and 13 formed on the upper and lower surfaces of the insulating plate 11 are set so as not to communicate with each other even at the intersection. Therefore, the bus bars 14 and 15 are insulated from each other except for the portion where the bent portion 20 is brought into contact with the upper and lower bus bars 14 and 15 through the opening 25.

As described above, the bent portion 20 of the bus bar 14 and the bus bar 15 which are brought into surface contact with each other through the opening 25 of the insulating plate 11 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 bent portion 20 and the lower electrode is brought into contact with the bus bar 14.

As described above, the bus bars 14 and 15 buried in the bus bar grooves 12 and 13 are welded to the upper and lower surfaces of the insulating plate 11 at required locations, so that the bus bars 14 and 1 are located at required locations.
5 can be conducted. 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. The bus bars 14 and 15 are assembled to the insulating plate 11 by welding the bus bars 14 and 15 with the insulating plate 11 interposed therebetween.

The terminal portions 22 and 24 bent at the edges of the upper and lower bus bars 14 and 15 on the insulating plate 11
And protrudes upward and downward, respectively.

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 plate.

FIG. 7 shows a second embodiment in which trapezoidal bent portions 20 and 28 are provided on both of the bus bars 14 and 15 of the cross portion for conducting, in the direction approaching each other.
As described above, when the bent portions 20 and 28 are provided on both bus bars, the depth H ′ of the bent portion can be reduced to 比較 compared with the case where the bent portion is provided on one side, and the bending operation is facilitated. It can be. The bent part 2
0 and 28 are passed through an opening 20 provided in the insulating plate 10, and the bottoms 20a and 28a are brought into surface contact, and resistance welding is performed as in the first embodiment.

FIGS. 8A and 8B show a third embodiment.
(A) shows the bottom 2 of the bent portion 20 of the bus bar 14.
A small projection 20b is further formed at the center of Oa by embossing. (B) shows a small protrusion 26 from the flat surface of the lower bus bar 15 which is brought into contact with the bottom 20 a of the bent portion 20.
Is protruding.

As described above, the small projections 20b (or 2
When 6) is protruded, the bus bars 14 and 15 come into point contact. If resistance welding is performed in this state, heat is likely to be generated,
Weldability can be improved.

FIGS. 9A and 9B show a fourth embodiment.
In the above embodiment, the bent portion is bent in a trapezoidal shape.
As shown in the figure, the bent portion 20 'is a bent portion having an arc shape. In the fourth embodiment, the bus bar 1 at the cross portion
4 and 15 are provided with arc-shaped bent portions, and the upper bus bar 14 is formed with the arc-shaped bent portion 2 facing downward.
The apex of 0 'and the apex of the arc-shaped bent portion 20' facing upward of the lower bus bar 15 are brought into contact through an opening of an insulating plate (not shown) to be interposed, and resistance welding is performed.

[0032]

As is apparent from the above description, according to the present invention, as the internal circuit of the electric junction box, strip-shaped bus bars are arranged in a grid pattern on the upper and lower surfaces of the insulating plate, and conduction at the intersection point is desired. In the portion, the opening is provided in the insulating plate, the bent portion provided in at least one bus bar is brought into contact with the other bus bar through the opening, and the contact portion is resistance-welded, so that conduction between the upper and lower bus bars is reliably and easily performed. It can be aimed at. 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.

[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 of the second embodiment.

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

FIG. 9A is an enlarged perspective view of a main part of a fourth embodiment,
(B) is a sectional view.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Circuit board 11 Insulating board 12, 13 Bus bar groove 14 Bus bar in X direction 15 Bus bar in Y direction 20, 20 'Bent part 20a Bottom part 20b Small projection 25 Opening

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 1/11 H05K 1/11 K F term (Reference) 5E317 AA21 AA24 BB01 BB11 CC02 CC11 GG16 5E338 AA02 AA16 BB02 BB12 BB25 BB28 BB63 CC01 CD05 CD10 CD15 EE32 5G361 BA04 BB02 BC01 5G365 CA06 CC06

Claims (7)

[Claims] 1. A bus bar having a rectangular shape is embedded in an X-direction bus bar groove formed parallel to one of upper and lower surfaces of an insulating plate, and a Y-direction bus bar groove formed parallel to one of upper and lower surfaces. At the intersections where the cross arrangement is made, an opening is provided in the insulation plate, and at least one of the bus bars to be conducted is trapezoidal or circular. A circuit board comprising an arcuate bent portion, the bent portion being brought into contact with the other bus bar through an opening in an insulating plate, and the contact portions of these bus bars being electrically connected by resistance welding. 2. The circuit board according to claim 1, wherein the bent portions are provided on both of the bus bars of the conductive portion, and the valleys of the bent portions are brought into contact with each other to perform resistance welding. 3. The depth of the bent portion of the bus bar is set at 0.
3. The circuit board according to claim 1, wherein the circuit board has a range of 3 mm to 8 mm. 4. The circuit board according to claim 1, wherein a small projection is provided on one of the contact surfaces of the bus bar that abut each other. 5. The circuit according to claim 1, wherein the bus bar in the X direction and the bus bar in the Y direction are cut out of unnecessary portions on a circuit to form a required circuit. Circuit board. 6. An electric junction box containing the circuit board according to claim 1. 7. The electric connection box according to claim 6, wherein a bus bar for connecting a power supply is arranged in a stack with the circuit board.