JP2001251727A - Connection structure of internal circuit in junction box to wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection structure with which an internal circuit in a junction box and a wire are connected without using a conductor. SOLUTION: A circuit board 13 is housed inside the junction box 10, is used embedded and molded integrally in a board 20, composed of an insulating resin in a state with the surface of a conductive part 21 composed of a highly conductive resin exposed. A core wire 18a, which is exposed at the terminal of a wire 18 at an external circuit, is brought into contact with a circuit composed of the conductive part and is bonded by a conductive adhesive 30 to be connected electrically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure between an internal circuit of a shunt box connected to a wire harness for an automobile and a wire for an external circuit constituting the wire harness.

[0002]

2. Description of the Related Art In recent years, with the rapid increase of electrical components mounted on automobiles, the number of electric junction boxes for automobiles, especially the circuits accommodated in junction boxes, has rapidly increased, and branch circuits are formed at high density. In addition, the number of parts is very large, and the number of assembling steps is very large.

In a junction box 1 shown in FIG. 9 among the electric connection boxes for automobiles, bus bars 5A to 5D are stacked and arranged between upper case 2 and lower case 3 with insulating plates 4A to 4E interposed therebetween. Further, an insulating plate 15 provided with wire guide grooves at both upper and lower ends is disposed,
5, wires 6A and 6B are laid and accommodated, and a connector accommodating portion, a relay accommodating portion, a relay 8 fitted in the fuse accommodating portion provided in the upper case 2 and the lower case 3 are connected to the bus bar by the bus bar. Tab 7 protruding from
And the above-mentioned electric wires 6A and 6B are press-connected to a press-contact terminal (not shown), and the press-connect terminal is connected to a connector,
Connected to terminals of relays and fuses.

[0004]

As described above, the internal circuit of the junction box is mainly of the bus bar type, but the electric wire and the press contact type in which a press contact terminal is connected to the electric wire may be used in some cases. In the case of the bus bar system, the connection with the external circuit wire is performed by attaching the relay terminal to the tab bent from the bus bar as described above, and fitting and connecting the relay terminal to the terminal of the wire terminal which is inserted and locked in the connector. Let me. Also in the case of the electric wire and the press contact terminal, the tab provided on the press contact terminal is fitted and connected to the terminal in the connector. In this way, all are connected via the connector housed in the connector housing provided on the outer surface of the junction box case, and on the wire side, the terminal is connected to the wire end,
It is necessary to insert and lock the terminal into the connector, and there is a problem that the number of parts and assembling man-hours are required. Also, it is necessary to provide a connecting terminal such as a tab on the internal circuit side such as a bus bar, and thus, there is a problem that a man-hour for processing is increased. is there.

[0005] Further, since the connector accommodating portions are usually provided on both the upper and lower surfaces of the junction box, it is necessary to detour the circuit from the bus bars or / and the electric wires to the connectors to be stacked, and the circuit design is extremely difficult. There are also problems such as complexity. Therefore, when the number of circuits to be taken into the junction box increases, the number of wiring circuits per layer decreases, and as a result, the number of layers increases,
There is a problem that the junction box becomes large and complicated. In addition, a large number of bus bars are required, and the bus must be formed from a mold in accordance with a change in the circuit, resulting in a very high cost. In addition, an insulating plate must be interposed between the bus bars, and there is a problem that the number of parts and the number of assembling steps increase.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the problem that an internal circuit and an external circuit wire housed in a junction box can be connected without providing terminals on the internal circuit side.
Another object of the present invention is to make it possible to directly connect without using a relay terminal and without a connector.

[0007]

In order to solve the above-mentioned problems, the present invention provides a circuit body housed in a junction box, wherein a surface of a conductive part made of a highly conductive resin is provided on a substrate part made of an insulating resin. The exposed portion is buried and integrally molded, and the conductive portion uses a circuit body formed in a required circuit, and inserts an electric wire for an external circuit through an opening provided on an outer surface of the junction box. The core wire exposed from the terminal is placed on the circuit of the circuit body,
The present invention provides a connection structure for connecting an internal circuit of a junction box to an external circuit wire, wherein the internal circuit is fixed by a highly conductive adhesive and electrically connected.

That is, as an internal circuit body housed in the junction box, a bus circuit, a wire and a press contact terminal, or a new circuit body different from the FPC used so far is used. As described above, the circuit body is buried in a circuit board portion made of an insulating resin and is integrally molded with the surface of the conductive portion made of a highly conductive resin being exposed, and the conductive portion is It is formed into the required circuit shape. As described above, when the conductive portion forming the circuit pattern is formed by injection molding a high conductive resin, the conductive portion can be efficiently arranged, a branch circuit can be provided with high density, and the core of the electric wire can be bonded with a high conductive adhesive. The connection can be made directly using an agent. As this highly conductive adhesive, one having a configuration in which silver powder, tin alloy powder or the like is dispersed in a matrix resin with a conductive filler, for example, the product name “Dordent” manufactured by Nihon Handa Co., Ltd. is preferably used.

In particular, of the circuits of the circuit body, the terminals of the circuit to be connected to the wires are concentrated and arranged side by side on one side of the circuit body, and the wires are wired in parallel to contact the corresponding circuits. ,
If you concentrate the bonding positions with the adhesive in parallel,
The bonding step using an adhesive can be performed at a time, and workability can be improved.

Specifically, an opening for inserting the electric wire is provided on a side surface where the upper case and the lower case of the junction box are joined, and the electric wire terminals constituting the wire harness are inserted through the opening and exposed from the electric wire terminals. It is preferable that the core wire is brought into contact with the upper surface (or lower surface) of a required circuit of the circuit body and fixed with a highly conductive adhesive.

As described above, when the circuit of the circuit body and the electric wire of the wire harness are connected, no connector such as a tab is provided on the circuit side, a relay terminal is not required, and a connector-less and direct wire is used. Can be connected to harness wires. Further, when the connection portion with the wire harness is provided on the side surface of the junction box, the number of connection points can be increased in addition to the connection on the upper and lower surfaces with the junction box, and the junction box can be used efficiently.

Further, the opening for inserting the electric wire is not limited to the side surface, but is provided on the upper surface of the upper case or / and the lower surface of the lower case of the junction box, and the electric wire is inserted into the case from the vertical direction to make contact with the circuit of the circuit body. It may be bent at the portion to be formed and connected with an adhesive.

When a bus box, an internal circuit comprising an electric wire and a press-connecting terminal is housed in a junction box and used in combination with the above-mentioned circuit body, as in the conventional case,
Connector housings are provided on the upper and lower surfaces of the junction box to connect the wire harness with the connector. Also,
It goes without saying that the circuit of the circuit body may be connected to the wire group of the wire harness via a relay pin or the like.

As the highly conductive resin agent for connecting the core wire of the electric wire and the circuit, a highly conductive resin forming a conductive portion of the circuit body can be used. In this case, a protrusion having an electric wire insertion groove is provided at an end of a circuit portion connected to the electric wire core wire of the circuit body, and after inserting the electric wire core wire into the electric wire insertion groove, the protrusion is heated and melted and bonded. Is preferred.

The conductive resin forming the circuit pattern is disclosed in JP-A-10-237331 and JP-A-11-342.
No. 522, in a thermoplastic resin,
It is made of a mixture of metal fibers made of copper, nickel, iron or the like, and a conductive resin composition in which a low-melting alloy such as lead-free solder (low-melting solder) and Cu powder is dispersed.

The thermoplastic resin to which conductive metal fibers are blended includes propylene, polyethylene, polystyrene, acrylonitrile / butadiene / styrene resin, modified polyphenylene oxide resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyamide resin, aromatic resin Polyamide resin, polyphenylene sulfide resin, liquid crystal polymer, polyetherimide,
Resins such as polybenzimidazole, polyetheretherketone, and polyethersulfone can be used alone or as a blend, and acrylonitrile-butadiene-styrene resin and polybutylene terephthalate resin are particularly preferably used.

As the low melting point alloy to be mixed and dispersed in the thermoplastic resin and to be bonded in a network, an alloy having a melting point of 100 ° C. or higher, preferably 200 ° C. or higher and melting at the time of injection molding is used. System, Sn-Ag
-Pb system, Sn-Bi system, Sn-Bi-In system, Bi-
Pb-based, Bi-Sn-based, Sn-Cu-based, Sn-Cu-N
i-P system, Sn-Ag system, Sn-Bi-Pb system, Sn-
In-based materials may be mentioned.

In the circuit body using the highly conductive resin as a conductive portion, a first injection molding (first color) using a mold is performed with an insulating resin to form a substrate portion. A second injection molding (second color) is performed with a highly conductive resin in a mold to form a conductive portion, and in two steps, a circuit body in which the substrate portion and the conductive portion are integrated into a flat plate shape is formed.

[0019]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of a junction box 10 connected to an automobile wire harness.
1 is an upper case, 12 is a lower case, and 13 (13
A and 13B) are circuit bodies, 14 is a bus bar, 15 is a single-core wire for press contact, 16 is a press contact terminal, 17 is a conductive pin, and 18 is an electric wire for an external circuit constituting a wire harness. Although not shown, an insulating plate is interposed between the circuit body 13 </ b> A and the bus bar 14, which are stacked adjacently.

As described above, the junction box 1
In the case of 0, an internal circuit composed of the bus bar 14 and the single core wire 15 and the pressure contact terminal 16 is used together with the circuit body 13, but the internal circuit may be constituted only by the circuit body 13. Although the circuit body 13 has two layers in the drawing, it is needless to say that the circuit body 13 may be a multilayer having two or more layers.

The circuit body 13 (13A, 13B) has a structure shown in FIGS. 2A, 2B, and 2C, and is provided on a substrate portion 20 made of an insulating resin and a conductive portion 21 (made of a highly conductive resin). (Indicated by diagonal lines in the figure)
It is integrally formed in a flat plate shape.

The surface 21a of the conductive portion 21 is
A required circuit is formed so as to be flush with the upper surface 20a of the zero. The circuit C connected to the external circuit wire 18
Extend in parallel to the edge on one side of the circuit body 13. The conductive portion 21 is not exposed on the lower surface 20b of the substrate portion 20 and is an insulating surface composed of only an insulating resin layer. The conductive portion 21 is also exposed on the outer peripheral surface 20c of the substrate portion 20.

In the manufacture of the circuit body 13, first, an insulating resin is injected into the cavities of the upper and lower molds, and a primary molded product consisting of only the substrate portion 20 is injection-molded. In this state, the conductive part 21 is not provided on the substrate part 20. Then, the upper mold is changed to another mold, joined to the lower mold and clamped, a cavity is formed between the substrate part 20 and the replaced upper mold, and a highly conductive resin is injected into the cavity. The conductive part 21 is injection molded. Thus, the circuit body 13 including the conductive portion 21 having a required circuit shape on the surface of the substrate portion 20 is integrally formed.

Among the circuits composed of the conductive portions 21 of the circuit body 13, the circuit C which needs to be connected with the electric wire 18 of the wire harness is provided in parallel on one side of the circuit body 13 as described above. FIG.
(A) As shown in (B), the core wire 18a exposed from the terminal of the electric wire 18 is placed on the upper surface of the circuit C, and the highly conductive adhesive 30 is applied and fixed. Is electrically connected.

As shown in FIG. 4, the electric wire w is inserted directly into the box through an opening 32 provided in a fitting portion on the side surface of the upper case 11 and the lower case 12 without a connector, as shown in FIG. . That is, the electric wire 1 is connected to the circuit body 13.
8 are fixed by lamination in the lower case 12, and thereafter, the electric wire 18 is drawn out from the opening 32 by covering the upper case 11.

When the circuit bodies 13A and 13B are stacked and arranged, and the electric wires 18 are bonded and fixed to the circuit bodies 13A and 13B, respectively, as shown in FIG.
The insulating surfaces of A and 13B are brought into contact with each other and laminated, the electric wire 18-1 is bonded to the circuit on the upper surface of the upper circuit body 13A, and the electric wire 18-2 is bonded to the circuit on the lower surface of the lower circuit body 18. I have.

As shown in FIG. 6A, a circuit portion made of a highly conductive resin fixed to the core wire 18a of the electric wire has
A protrusion 35 having a U-shaped wire insertion groove 35a is provided in advance by integral molding, and as shown in FIG. 6B, the core wire 18a of the wire is inserted into the wire insertion groove 35a.
The highly conductive resin of No. 5 may be heated and melted and bonded to the core wire 18a.

Further, it is not necessary to arrange the bonding positions of the electric wires 18 and the circuit in parallel. As shown in FIG. 7, the electric wires 18 are extended to a required circuit position, and the terminal core wire 18a is connected to the circuit C.
What is necessary is just to adhere and fix. At this time, since the wires 18 are insulated and coated except for the terminal core wires, there is no problem even if the upper surfaces of other circuits are in contact with each other, without changing the configuration of the circuit body 18.
It is possible to cope with a circuit change only by changing the bonding position between the terminal core wire of the electric wire 18 and the circuit.

As described above, the electric wires 18 can be directly connected to the conductive portions 21 constituting the circuit of the circuit body 13, but the connector housing portions 11a, 12a provided on the upper case 11 and the lower case 12 and the fuses are provided. Accommodation section 11b,
12b and the terminals housed in the relay housing part 12c are shown in FIG.
As shown in (1), this may be performed via conductive pins 17 having tabs 17a and 17b formed at both upper and lower ends. That is, the circuit body 1
The tab 17b at one end of the conductive pin 17 is press-fitted into the insertion hole 26 provided in the conductive portion 21 of the third portion so as to make surface contact, while the female terminal of the wire terminal in the connector to be inserted into the connector accommodating portion and the other end of the conductive pin 17 And the tab 17a.
Conductive pin 17 when connecting to a fuse or relay terminal
May be provided with a female terminal at one end.

[0030]

As is apparent from the above description, according to the present invention, as an internal circuit of the junction box,
Uses a circuit body in which the conductive part made of highly conductive resin is integrally molded with the board part made of insulating resin, so that the degree of freedom in circuit design is high, high-density wiring is possible, and the size and weight of the junction box are reduced. And so on. Also, when the terminal core wire of the external circuit electric wire is brought into contact with the conductive portion constituting the circuit of the circuit body and bonded using a highly conductive adhesive, the electric wire and the internal circuit are connected without a connector. can do.

Therefore, terminal connection on the electric wire side and assembling of the connector to the terminal are not required, but on the internal circuit side of the junction box, there is no need to provide terminals such as tabs, so that the number of parts and the number of assembling steps are greatly reduced. As a result, a reduction in the production cost of the junction box can be achieved.

Further, the circuit configuration can be easily changed only by changing the bonding position between the terminal core wire of the electric wire and the circuit.
It is possible to easily cope with a change in circuit design, and thus it is possible to share the circuit body itself.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a junction box according to an embodiment of the present invention.

FIGS. 2A and 2B show a circuit body, wherein FIG. 2A is a perspective view, FIG. 2B is a view taken in the direction of arrow X in FIG. 2A, and FIG.

FIGS. 3A and 3B are views showing a process of connecting a circuit of a circuit body and an electric wire.

FIG. 4 is a schematic perspective view showing an insertion form of a wire connected to a circuit of a circuit body into a junction box.

FIG. 5 is a schematic sectional view showing a modification.

FIG. 6A is a schematic sectional view showing another modified example,
(B) is a schematic sectional view showing a bonding step with an electric wire.

FIG. 7 is a schematic diagram showing a modification of a connection position between an electric wire and a circuit.

FIG. 8 is a schematic diagram showing a method for connecting a circuit body and an electric wire with a connector.

FIG. 9 is an exploded perspective view of a conventional junction box.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Junction box 11 Upper case 12 Lower case 13 (13A, 13B) Circuit body 14 Bus bar 15 Single core wire 17 Conducting pin 18 External circuit electric wire 18a Core wire 20 Substrate part 21 Conductive part 30 High conductive adhesive 32 Opening 35 Projection 35a Electric wire insertion Groove C circuit

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor: Yuki Saito, 1-114, Nishisuehirocho, Yokkaichi, Mie Prefecture Inside Sumitomo Wiring Systems, Ltd. (72) Inventor: Nobufumi Kobayashi, 1-14, Nishisuehirocho, Yokkaichi, Mie Prefecture No. Sumitomo Wiring Systems, Inc. F-term (reference) 5G361 BA07 BB01 BC01 BC02

Claims (4)

[Claims] 1. A circuit body housed in a junction box, which is buried in a substrate portion made of an insulating resin with a surface of a conductive portion made of a highly conductive resin being exposed and integrally molded, and The part uses a circuit body formed in a required circuit, inserts an electric wire constituting an external circuit from an opening provided on the outer surface of the junction box, and inserts a core wire exposed from the end of the electric wire on the circuit of the circuit body. A connection structure for connecting an internal circuit of the junction box to an electric wire, wherein the connection circuit is mounted on the substrate and is electrically connected by being fixed with a highly conductive adhesive. 2. The inside of the junction box according to claim 1, wherein the circuit body has a substantially flat plate shape, and the wire insertion opening is provided on a side surface of the junction box where the upper case and the lower case are joined. Connection structure between circuit and electric wire. 3. The junction box according to claim 1, wherein a high conductive resin forming a conductive portion of the circuit body is used as the high conductive resin agent for connecting the core of the electric wire and the circuit. Connection structure between the internal circuit and the wires. 4. A circuit having an electric wire insertion groove provided in a circuit connected to an electric wire core wire of said circuit body, and said electric wire core wire inserted into said electric wire insertion groove is bonded by heating and melting said protrusion. Item 3. A connection structure between an internal circuit of a junction box and an electric wire according to item 3.