JP3506094B2 - Connection structure between the internal circuit of the junction box and electric wires - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Recently, with the rapid increase in electrical components mounted on automobiles, the number of circuits contained in automobile electrical junction boxes, especially junction boxes, has increased rapidly to form branch circuits with high density. Moreover, the number of parts is extremely large, and the number of assembling steps is also very large.

In the junction box 1 shown in FIG. 9 of the automobile electrical junction box, bus bars 5A to 5D are laminated between the upper case 2 and the lower case 3 with insulating plates 4A to 4E interposed therebetween. Further, the insulating plate 15 provided with the wire guide grooves at both upper and lower ends is arranged, and the insulating plate 1
The wires 5A and 6B are wired and housed on the housing 5, and the connector housing, the relay housing, and the relay 8, which is fitted in the fuse housing, provided in the upper case 2 and the lower housing 3, the fuse, and the terminal of the connector are connected to the bus bar. Tab 7 protruding from
And connecting the electric wires 6A and 6B to a pressure contact terminal (not shown), and connecting the pressure contact terminal to a connector,
It is connected to the relay and fuse terminals.

[0004]

As described above, the internal circuit of the junction box is mainly of the bus bar type, but there are also cases where both the electric wire and the pressure welding method in which the pressure welding terminal is connected to the electric wire are used together. In the case of the bus bar method, the connection with the electric wire for the external circuit is performed by fitting the relay terminal to the tab bent from the bus bar and inserting the relay terminal into the connector to engage the terminal of the electric wire terminal as described above. I am letting you. Also, in the case of an electric wire and a pressure contact terminal, the tab provided on the pressure contact terminal is fitted and connected to the terminal in the connector. In this way, both are connected via the connector accommodated in the connector accommodating portion provided on the outer surface of the case of the junction box, and on the electric wire side, the terminal is connected to the electric wire end,
Since it is necessary to insert and lock the terminal into the connector, there is a problem that the number of parts and the number of assembling steps are increased, and it is necessary to provide a connecting terminal such as a tab even on the internal circuit side such as a bus bar, which causes a problem of increasing the number of processing steps. is there.

Further, since the connector accommodating portions are usually provided on both upper and lower surfaces of the junction box, it is necessary to bypass the circuit between the bus bar or / and the electric wire and the connector, which are arranged in layers, and the circuit design is very difficult. There are also problems such as complexity. Therefore, if the number of circuits that take in 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 it is necessary to form them from a mold according to circuit changes, which is very expensive. In addition, an insulating plate must be interposed between the bus bars, which increases the number of parts and the number of assembly steps.

The present invention has been made in view of the above problems, and the internal circuit housed in the junction box and the external circuit electric wire are provided without providing terminals on the internal circuit side.
Moreover, it is an object to make it possible to directly connect without a relay terminal and without a connector.

[0007]

In order to solve the above problems, the present invention comprises a circuit body housed in a junction box, wherein the circuit body is a first injection molding (1) of an insulating resin by a mold. The substrate part is molded with different colors, and this substrate part is moved into another mold and metal fiber or low melting point alloy is dispersed in the thermoplastic resin to inject a highly conductive resin that is joined in a network form. Molding (second color), and in these two steps, the conductive part made of a highly conductive resin is embedded in a substrate part made of an insulative resin in an exposed state to be integrally molded. Is formed in the circuit,
An electric wire that constitutes an external circuit is inserted through an opening provided on the outer surface of the junction box, and the core wire exposed from the electric wire end is placed on the circuit of the circuit body and fixed with a highly conductive adhesive. It provides a connection structure between an internal circuit of a junction box and an electric wire, which is electrically connected.

That is, as the internal circuit body housed in the junction box, a new circuit body different from the bus bar, the electric wire and the pressure contact terminal, or the FPC used so far is used. As described above, the circuit body is embedded and integrally molded in a circuit board portion made of an insulating resin with the surface of the conductive portion made of a highly conductive resin exposed. It is molded into the required circuit shape. In this way, when the conductive parts forming the circuit pattern are formed by injection-molding a highly conductive resin, the conductive parts can be efficiently arranged, branch circuits can be provided at high density, and the core wire of the wire is highly conductively bonded. It can be directly connected using an agent. As the highly conductive adhesive, one having a structure in which a conductive filler is dispersed in a matrix resin, such as silver powder, tin alloy powder, or the like, for example, trade name "Dodent" manufactured by Nihon Handa Co., Ltd. is preferably used.

In particular, among the circuits of the circuit body, the terminals of the circuits to be connected to the electric wires are concentrated and arranged side by side on one side of the circuit body, while the wires are wired in parallel and brought into contact with the corresponding circuits. ,
If the adhesion positions by the adhesive are concentrated in parallel,
The bonding process using the adhesive can be performed at one time, and the workability can be improved.

Specifically, the opening for inserting the electric wire is provided on the 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 these electric wire terminals. It is preferable that the core wire is brought into contact with the upper surface (or lower surface) of a desired circuit of the circuit body and fixed with a highly conductive adhesive.

When the circuit of the circuit body and the electric wire of the wire harness are connected as described above, a terminal such as a tab is not provided on the circuit side, a relay terminal is not required, and the wire is directly connected without a connector. Can be connected to the wire of the harness. Further, by providing the connection portion with the wire harness on the side surface of the junction box, it is possible to increase the number of connection points in addition to the connection with the upper and lower surfaces of the junction box, so that the junction box can be efficiently used.

Further, the opening for inserting the electric wire is not limited to the side surface, and is provided on the upper surface of the upper case of the junction box and / or the lower surface of the lower case, and the electric wire is vertically inserted into the case to make contact with the circuit of the circuit body. You may refract in the part to make and connect with an adhesive agent.

When a junction box contains an internal circuit consisting of a bus bar, an electric wire and a pressure contact terminal and is 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 for connector connection with the wire harness. Also,
It goes without saying that the circuit of the circuit body may be connected to the electric wire group of the wire harness by a connector 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 the conductive portion of the circuit body can be used. In that case, a protrusion having an electric wire insertion groove is provided at the end of the circuit portion connected to the electric wire core wire of the circuit body, and the electric wire core wire is inserted into the electric wire insertion groove, and then the protrusion is heated and melted to adhere. It is preferable.

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

Examples of the thermoplastic resin to which the conductive metal fibers are mixed include propylene, polyethylene, polystyrene, acrylonitrile butadiene styrene resin, modified polyphenylene oxide resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyamide resin, and aromatic resin. Polyamide resin, polyphenylene sulfide resin, liquid crystal polymer, polyetherimide,
Resins such as polybenzimidazole, polyether ether ketone, and polyether sulfone can be used alone or in a blend, and acrylonitrile / butadiene / styrene resin and polybutylene terephthalate resin are particularly preferably used.

As the low melting point alloy which is mixed with the above thermoplastic resin and dispersed and bonded in a network state, an alloy having a melting point of 100 ° C. or higher, preferably 200 ° C. or higher, which melts during injection molding is used. Sn-Pb System, Sn-Ag
-Pb system, Sn-Bi system, Sn-Bi-In system, Bi-
Pb type, Bi-Sn type, Sn-Cu type, Sn-Cu-N
i-P system, Sn-Ag system, Sn-Bi-Pb system, Sn-
In-based ones are mentioned.

As described above, in the circuit body using the highly conductive resin as the conductive portion, the first injection molding (first color) by the mold is performed with the insulating resin to mold the substrate portion, and the substrate is formed. The second part is molded by another mold with a highly conductive resin for the second injection molding (second color) to mold the conductive part. In two steps, a circuit body in which the substrate part and the conductive part are integrated into a flat plate shape is formed. Molded.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION 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, 13 (13
A, 13B) is a circuit body, 14 is a bus bar, 15 is a single core wire for pressure contact, 16 is a pressure 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 13A and the bus bar 14 which are adjacently stacked.

As described above, the junction box 1
In No. 0, the internal circuit including the bus bar 14, 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 configured by only the circuit body 13. Further, although the circuit body 13 has two layers in the drawing, it goes without saying that the circuit body 13 may have two or more layers.

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

The surface 21a of the conductive portion 21 is the substrate portion 2
A required circuit is formed so as to be exposed flush with the upper surface 20a of 0. Also, a circuit C connected to the external circuit electric wire 18
Are extended in parallel to one side edge 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 formed only of 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 composed only of the substrate portion 20 is injection molded. In this state, the board portion 20 is not provided with the conductive portion 21. Then, the upper mold is changed to another mold, the lower mold is joined and the mold is clamped, a cavity is formed between the substrate part 20 and the upper mold which has been exchanged, and a highly conductive resin is injected into this cavity. The conductive part 21 is injection molded. As a result, the circuit body 13 including the conductive portion 21 having a desired circuit shape is integrally formed on the surface of the substrate portion 20.

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

As shown in FIG. 4, the electric wire w is directly inserted into the box without a connector through an opening 32 provided in a fitting portion on a side surface of the upper case 11 and the lower case 12 in a parallel wiring state. . That is, the electric wire 1 is connected to the circuit body 13.
8 are bonded and fixed to be stacked and arranged in the lower case 12, and then the upper case 11 is covered and the electric wire 18 is drawn out from the opening 32 to the outside.

When the circuit bodies 13A and 13B are laminated and the electric wires 18 are adhesively 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 to be laminated, the electric wire 18-1 is adhered to the upper circuit of the upper circuit body 13A, and the electric wire 18-2 is adhered to the lower circuit of the lower circuit body 18. There is.

As shown in FIG. 6 (A), the circuit portion made of a highly conductive resin that is fixed to the core wire 18a of the electric wire,
The projection 35 having the U-shaped wire insertion groove 35a is previously provided by integral molding, and the core wire 18a of the wire is inserted into the wire insertion groove 35a as shown in FIG.
The high-conductivity resin of No. 5 may be melted by heating and bonded to the core wire 18a.

Further, it is not necessary to arrange the adhesion positions of the electric wire 18 and the circuit in parallel, and as shown in FIG. 7, the electric wire 18 is extended to a desired circuit position and its terminal core wire 18a is connected to the circuit C.
It can be fixed by adhesion. At that time, since the electric wire 18 is insulation-coated except for the terminal core wire, there is no problem even if the upper surface of another circuit is contacted, and the configuration of the circuit body 18 is not changed.
The circuit can be changed only by changing the bonding position between the terminal core wire of the electric wire 18 and the circuit.

As described above, the electric wire 18 and the conductive portion 21 constituting the circuit of the circuit body 13 can be directly connected, but the connector housing portions 11a and 12a provided in the upper case 11 and the lower case 12 and the fuse. Housing portion 11b,
12b and the terminals accommodated in the relay accommodating portion 12c are as shown in FIG.
Alternatively, as shown in FIG. 5, the conductive pin 17 may have tabs 17a and 17b formed at both upper and lower ends. That is, the circuit body 1
While 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 No. 3 to make surface contact, 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 are inserted. The tab 17a is fitted and connected.
Conductive pin 17 when connecting to a fuse or relay terminal
It suffices to provide a female terminal portion at one end of.

[0030]

As is apparent from the above description, according to the present invention, as the 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 substrate part made of insulating resin, allowing a high degree of freedom in circuit design, enabling high-density wiring, and making the junction box smaller and lighter. And so on. Further, when the terminal core wire of the electric wire for the external circuit is brought into contact with the conductive portion forming the circuit of the circuit body and bonded by using the highly conductive adhesive, the electric wire and the internal circuit are connected without a connector. can do.

Therefore, on the electric wire side, terminal connection and connector assembly of the terminal are not required, but on the internal circuit side of the junction box, it is not necessary to provide terminals such as tabs, and the number of parts and the number of assembling steps are greatly reduced. As a result, the manufacturing cost of the junction box can be reduced.

Furthermore, the circuit configuration can be easily changed by simply 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 the circuit design, and thus it is possible to share the circuit body itself.

[Brief description of drawings]

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

2A and 2B show a circuit body, in which FIG. 2A is a perspective view, FIG. 2B is a view taken along arrow X in FIG. 2A, and FIG.

3A and 3B are drawings 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 mode of an electric wire connected to a circuit of a circuit body into a junction box.

FIG. 5 is a schematic sectional view showing a modified example.

FIG. 6A is a schematic cross-sectional view showing another modification,
(B) is a schematic sectional drawing which shows the adhesion process with an electric wire.

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

FIG. 8 is a schematic view 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]

10 junction box 11 upper case 12 lower case 13 (13A, 13B) Circuit body 14 Busbar 15 Single core wire 17 Conduction pin 18 Electric wire for external circuit 18a core wire 20 board part 21 Conductive part 30 Highly conductive adhesive 32 openings 35 Protrusion 35a Wire insertion groove C circuit

Front page continuation (72) Inventor Nobufumi Kobayashi 1-14 Nishisuehiro-cho, Yokkaichi-shi, Mie Sumitomo Wiring Systems, Ltd. (56) Reference JP-A-2-139216 (JP, A) JP-A-9-92987 (JP, A) JP-A-11-312849 (JP, A) JP-A-6-291160 (JP, A) JP-A-10-173305 (JP, A) JP-A-63-7128 (JP, A) Actual Kaihei 5-11472 (JP, U) Actual Kaihei 5-77817 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02G 3/16 B60R 16/02 H05K 5/00

Claims (4)

(57) [Claims] 1. A junction box is provided with a circuit body housed in the junction box, wherein the circuit body is formed by a first injection molding of an insulating resin.
The board part is molded in the shape (first color), and this board part is
Move it into the mold and add metal fibers or low melting
A high-performance structure in which point alloys are dispersed and joined in a network.
Injection molding (second color) of conductive resin and
Conductive part made of highly conductive resin on the substrate made of edge resin
It is embedded and molded integrally with the surface of the
The conductive portion is formed in a required circuit, and an electric wire constituting an external circuit is inserted through an opening provided on the outer surface of the junction box, and the core wire exposed from the electric wire end is mounted on the circuit of the circuit body. A connection structure between an internal circuit of a junction box and an electric wire, characterized in that it is fixed and electrically connected by 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 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. Connection structure between circuit and electric wire. 3. The junction box according to claim 1, wherein a highly conductive resin that forms a conductive portion of the circuit body is used as a highly conductive adhesive that connects the core wire of the electric wire and a circuit. Connection structure between the internal circuit and the electric wire. 4. A projection having an electric wire insertion groove is provided on a circuit connected to the electric wire core wire of the circuit body, and the core wire of the electric wire inserted in the electric wire insertion groove is adhered by heating and melting the projection. Item 3. A connection structure between an internal circuit of the junction box and an electric wire according to Item 3.