JP2008108578A - Splice structure of flexible flat cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To branch and connect FFCs with a simple working process and without taking a space and causing a limit to current-carrying capacity. <P>SOLUTION: This is a connection structure to branch and connect FFCs 20, 30 covering a conductor with an insulating film at a prescribed position. In the FFCs, only the insulating film covering connecting portions 21a, 31a of the conductors 21, 31 is peeled off in a hole shape, and the FFCs 20, 30 are arranged so that the exposed conductors may face each other, and an anisotropic conductive adhesive film 40 having conductivity in the thickness direction and insulation property in surface direction is interposed between these conductors 21, 31. The conductors of the FFCs are contacted with both faces 40a, 40b in the thickness direction of the anisotropic conductive adhesive film and adhered. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a splice structure of a flexible flat cable (hereinafter abbreviated as FFC), in which a branch line FFC is overlapped with a main line FFC to connect required conductors with each other.

2. Description of the Related Art Conventionally, a wire harness in which electric wires are converged has been routed in a vehicle in order to connect electrical components mounted on a vehicle.
However, as the number of electrical components increases, the number of wires in each wire harness increases, the wire harness diameter is enlarged, a wide wiring space is required, and the weight is not negligible relative to the weight of the vehicle. .
Therefore, recently, the FFC in which a plurality of conductors made of copper foil are arranged in parallel and laminated with an insulating resin film can be made flatter and lighter than a wire harness in which the electric wire group is converged. It is widely used for circuits.

  In vehicle electrical components, the positions of the signal circuit and the ground circuit are different, or a plurality of electrical components are often connected to the same fuse, and it is necessary to branch the branch circuit from the main circuit and connect them. For this reason, various connection methods for splicing the branch line FFC to the main line FFC have been proposed.

  For example, in Japanese Patent Application Laid-Open No. 2003-134630 (Patent Document 1), as shown in FIG. 8, a pierce terminal in which a terminal plate 2 is connected to a female terminal 1 and clamp pieces 3 project from both sides of the terminal plate 2. 4, the clamp piece 3 of the piercing terminal 4 is pierced at a location corresponding to the conductor 6 of the FFC 5, and the tip of the clamp piece 3 is crimped. By connecting the branching conductor 6 to the female terminal 1 of the piercing terminal 4, the FFC 5 can be branched.

JP 2003-134630 A

  However, since the pierce terminal must be attached to each conductor of the FFC, if the number of connection circuits is increased, the process of attaching the pierce terminal is increased and the cost is increased. Furthermore, the connection work itself performed by aligning the conductors is required to have a high degree of accuracy so that the position detection by a camera or the like is required, and the equipment becomes expensive. In addition, since conduction is performed only on the contact surface between the clamp piece of the pierce terminal and the conductor, there is a problem that the energization capacity is limited.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to enable connection of a plurality of conductors at a time, and to enable splicing of FFC without causing a restriction on current carrying capacity. Yes.

In order to solve the above problems, the present invention provides:
A flexible flat cable (FFC) splice connection structure in which a plurality of conductors are covered with an insulating film,
Only the insulating film covering the splice connection portion of each conductor of the FFC is peeled off in a perforated form to expose the conductor of the splice connection portion,
The FFCs are overlapped so that one or a plurality of exposed conductors face each other, and an anisotropic conductive adhesive having conductivity in the thickness direction and insulation in the surface direction between these conductors A flexible flat cable splice structure is provided, wherein a film is interposed and the FFC conductor is bonded and connected to both surfaces of the anisotropic conductive adhesive film in the thickness direction.

In the present invention, as described above, the conductive material for splice connection is not a connection using a terminal fitting such as a pierce terminal for each conductor of the conventional example, but an anisotropic conductive adhesive having conductivity only in one direction. A film is used as a conductive material.
The anisotropic conductive adhesive film is a film in which conductive metal fibers are oriented in the thickness direction in an insulating resin having adhesiveness, and only the conductors in the thickness direction where both ends of the conductive metal fibers are in contact with each other. Are electrically conductive.
That is, the anisotropic conductive adhesive film only has a function of conducting the conductors bonded at both ends of each conductive metal fiber, and does not conduct between the conductive metal fibers, and the conductors in contact with the metal fibers are different. No conduction occurs between these conductors.
Therefore, when one anisotropic conductive adhesive film is used and interposed between different conductors at a plurality of locations, the conductors can be electrically connected to each other and insulated from other conductors.

By using the anisotropic conductive adhesive film having the above function, in the present invention, only a single anisotropic conductive adhesive film is interposed between a plurality of sets of conductors of FFCs. Are connected. In addition, according to a circuit structure, you may connect one set of conductors with one anisotropic conductive adhesive film.
In this way, not only for each conductor, but also for simultaneous connection of a plurality of conductors, and because it can be fixed simply by placing and pressing FFCs on both sides of an anisotropic conductive adhesive film having adhesive properties, splice connection between FFCs Can be easily formed, and the process of attaching the conductive material at the splice connection can be greatly reduced. In addition, even if the positions of the splice connecting portions exposed by peeling off the insulating film are slightly shifted, it is possible to ensure conduction by bonding with an anisotropic conductive adhesive film. This eliminates the need for high-accuracy alignment that is necessary when conducting the operation, makes it unnecessary to detect the position with an expensive camera, and reduces the equipment cost.
In addition, by increasing the area of the splice connection part that peels off and exposes the insulating film of each FFC and conducts the entire area through the anisotropic conductive adhesive film, the allowable energization amount at the splice connection part is increased. It can also be increased.
Furthermore, since the anisotropic conductive adhesive film is merely interposed between the FFCs, and there is no exposure of the FFC to the outer surface that occurs when the piercing terminal fitting is used, it is not necessary to insulate the outer surface exposed portion. Furthermore, since the anisotropic conductive adhesive film is a thin flat film, it does not hinder flattening, which is an advantage of FFC.

Specifically, each FFC uses the one in which the conductor having a rectangular cross section is continuous in a strip shape, and a plurality of the conductors are arranged in parallel at intervals and laminated with the insulating film, and the superposition is performed. One FFC is for the main line, the other FFC is for the branch line,
In the trunk FFC, the conductors of the plurality of splice connection portions are individually exposed at intermediate positions in the length direction, whereas in the branch FFC, required conductors are individually exposed at one end position in the length direction.
With respect to the intermediate position where the conductor of the main line FFC is exposed, one end of the branch line FFC is positioned in an orthogonal direction or an inclined direction, the exposed conductors are opposed to each other, and the anisotropy is interposed therebetween. They are connected via a conductive adhesive film.

  As described above, even if an FFC serving as a branch line with respect to an FFC serving as a trunk line is disposed in an orthogonal direction or an inclination direction corresponding to the wiring direction, the conductors are overlapped with each other and anisotropic conductive bonding is performed therebetween. If a film can be interposed, splice connection can be achieved.

It is preferable that the conductor of the connection part which peels and exposes the said insulating film in the shape of a hole has shifted the position in the length direction between the conductors of an adjacent position.
That is, when connecting parallel conductors, the anisotropic direction is formed by forming a perforated portion of an insulating film on the same line in the width direction orthogonal to the length direction of the FFC, and exposing the exposed conductors to each other. However, since the gap between adjacent conductors of the FFC is narrow, it is necessary to shift the position in the length direction as described above for more reliable insulation. Is preferred.

As described above, according to the FFC splice connection structure of the present invention, the FFC conductors are connected to each other through the anisotropic conductive adhesive film. It can be carried out simultaneously only by interposing an anisotropic conductive adhesive film. Thus, since the splice connection portion can be easily formed, the manufacturing cost can be reduced.
Further, when the exposed area of the conductor is increased to increase the area in contact with the anisotropic conductive adhesive film, the area where the conductors conduct is increased, so that the current carrying capacity can be increased.
Furthermore, since only a thin anisotropic conductive adhesive film is interposed between the FFCs, the flatness of the FFC is not hindered, and the splicing connection part is an obstructive factor in the FFC routing in a flat routing space. Don't be.

Embodiments of the present invention will be described with reference to the drawings.
1 to 3 show a first embodiment of the present invention.
In the first embodiment, one end in the length direction of the branch line FFC 30 is placed on the upper surface of the intermediate position of the main line FFC 20 in a perpendicular direction with the anisotropic conductive adhesive film 40 interposed therebetween. The conductors 21A and 21B and the conductors 31A and 31B of the branch line FFC 30 are electrically connected by the anisotropic conductive adhesive film 40, respectively.

  The main line FFC 20 includes a plurality of conductors 21 having a rectangular cross-section that are continuous in a strip shape (in the present embodiment, only two conductors 21A and 21B are shown) arranged in parallel with an interval between them. Are laminated with the first insulating film 22 and the second insulating film 23. At the middle position in the length direction X, only the first insulating film 22 on the upper surface side is cut into a square shape with a laser to form hole portions 24A and 24B, and the necessary conductors 21 are individually exposed, and the branch line FFC 30 and Splice connection portions 21A-a and 21B-a. The splice connecting portion 21a is displaced in the length direction X between the conductors 21 at adjacent positions.

  The branch line FFC 30 has the same shape as the main line FFC 20, the conductors 31 A and 31 B arranged in parallel are laminated with the first insulating film 32 and the second insulating film 33, and the required conductors 31 are individually exposed to the main line. Connection portions 31A-a and 31B-a with the FFC 20 are used. It differs from the main FFC 20 in that the connecting portion 31a is provided by cutting off the second insulating film 33 on the lower surface side at one end position in the length direction Y of the branch FFC 30.

  One end of the branch line FFC 30 is positioned so that the length direction X of the main line FFC 20 and the length direction Y of the branch line FFC 30 are orthogonal to the intermediate position in the length direction X of the main line FFC 20. Each of the connecting portions 21a and each connecting portion 31a of the branch line FFC 30 are opposed to each other.

The anisotropic conductive adhesive film 40 is interposed between the connecting portions 21a and 31a. As shown in FIG. 1 (B), the anisotropic conductive adhesive film 40 is made of a film in which conductive metal fibers F are oriented in the thickness direction Z and embedded in an insulating resin P having adhesive properties. Both ends of the metal fiber F are exposed on the upper and lower end surfaces 40a, 40b in the thickness direction Z.
The conductive metal fiber F is made of nickel fiber or the like, the insulating resin is made of epoxy resin, polyamide resin, or the like, and the thickness is about 100 μm.

  When both end faces 40a, 40b in the thickness direction Z of the anisotropic conductive adhesive film 40 come into contact with the splice connecting portions 21a, 31a of the conductors 21, 31 of each FFC, they are electrically connected to both ends of each conductive metal fiber F. Conductors 21 and 31 are electrically connected. At that time, since the other conductive metal fibers F are insulated by the insulating resin P, they do not conduct in the plane direction orthogonal to the thickness direction Z, and the conductors 21A and 21B and 31A and 31B do not conduct. Insulating properties are maintained.

  Since the insulating resin P of the anisotropic conductive adhesive film 40 is tacky, a required pressure is applied from both the upper and lower surfaces of the trunk FFC 20 and the branch FFC 30 with the anisotropic conductive adhesive film 40 interposed therebetween. Thus, both surfaces of the anisotropic conductive adhesive film 40 are fixed to the main line FFC 20 and the branch line FFC 30. That is, the anisotropic conductive adhesive film 40 is fixed to the conductors 21 and 31 at the perforated portions where the insulating films of the FFCs 20 and 30 are peeled off, and is fixed to the surface of the insulating film at the portions where the insulating films are not peeled off.

According to the above-described configuration, the conductors 21 and 31 of the main line FFC 20 and the branch line FFC 30 are exposed, and the conductor 21A, the conductor 31A, and the conductor 21B are simply connected to the splice connection portions 21a and 31a via the anisotropic conductive adhesive film 40. The conductors 31B can be individually conducted.
Thus, since a plurality of conductors of the main line FFC 20 and the branch line FFC 30 can be spliced to each other with a single anisotropic conductive adhesive film 40, the manufacturing process of the splice connection part is compared with the conventional one. And can be very simple.

FIG. 4 shows a second embodiment of the present invention.
The second embodiment is different from the first embodiment in that one end of the branch line FFC 30 is positioned in the inclined direction with respect to the intermediate position in the length direction of the main line FFC 20.
If the connecting portions 21a and 31a of the main line FFC 20 and the branch line FFC 30 are electrically connected to each other through the anisotropic conductive adhesive film 40, the angle in the inclination direction can be freely set. Since the angle between the length direction X of the main line FFC 20 and the length direction Y of the branch line FFC 30 can be branched and connected not only in the orthogonal direction but also in the inclined direction, the degree of freedom of FFC routing in the vehicle is increased. Can do.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

5 to 7 show a third embodiment of the present invention.
In the third embodiment, the perforated portion 24 of the first insulating film 22 of the main line FFC 20 and the perforated portion 34 of the second insulating film 33 of the branch line FFC 30 have the same square shape, and the anisotropic conductive adhesive film 40 is It has the same shape as the perforated portions 24 and 34.
The thickness of the anisotropic conductive adhesive film 40 is the sum of the thicknesses of the first insulating film 22 of the main line FFC 20 and the second insulating film 33 of the branch line FFC 30, and the cross-sectional shape is the perforated portions 24, 34. The divided bodies 40-1 and 40-2 having the same square shape are provided.

  The method of forming the splice connection part of the third embodiment is that for the branch line after the anisotropic conductive adhesive film segments 40-1 and 40-2 are fitted into the splice connection parts 21A-a and 21Ba of the main line FFC 20, respectively. The FFC 30 is put on, the perforated portion 34 is fitted into the divided bodies 40-1 and 40-2, and the price connecting portions 31A-a and 31B-a are brought into contact with the upper surfaces of the divided bodies 40-1 and 40-2. In this state, by applying pressure from the upper and lower surfaces of the main line FFC 20 and the branch line FFC 30, both end surfaces in the thickness direction Z of the split bodies 40-1 and 40-2 of the anisotropic conductive adhesive film and the splices of the respective FFCs The connection portions 21a and 31a are brought into contact with each other to be conducted.

According to the above configuration, since the anisotropic conductive adhesive film 40 is used only as the split bodies 40-1 and 40-2 for the splice connection portions 21a and 31a, the anisotropic conductive adhesive film 40 is used. The amount can be reduced and the cost can be reduced.
Further, since the anisotropic conductive adhesive film 40 is disposed in a space formed by the perforated portions 24 and 34 of the main line FFC 20 and the branch line FFC 30, the thickness of the branch part between the main line FFC 20 and the branch line FFC 30 is made thinner. can do.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a first embodiment of the present invention, where (A) is an exploded perspective view and (B) is an enlarged sectional view of an anisotropic conductive adhesive film. It is a perspective view which shows the splice connection structure of FFC of 1st Embodiment. It is the sectional view on the AA line of FIG. It is a perspective view which shows the splice connection structure of FFC of 2nd Embodiment. It is a disassembled perspective view of 3rd Embodiment. It is a perspective view which shows the splice connection structure of FFC of 3rd Embodiment. It is the BB sectional view taken on the line of FIG. It is drawing which shows a prior art example.

Explanation of symbols

20 FFC for main line
30 FFC for branch line
21, 31 Conductors 21a, 31a Connection portions 22, 32 First insulating film 23, 33 Second insulating film 24, 34 Perforated portion 40 Anisotropic conductive adhesive films 40a, 40b Both end surfaces 40-1, 40-2 Split body

Claims (4)

A flexible flat cable (FFC) splice connection structure in which a plurality of conductors are covered with an insulating film,
Only the insulating film covering the splice connection portion of each conductor of the FFC is peeled off in a perforated form to expose the conductor of the splice connection portion,
The FFCs are overlapped so that one or a plurality of exposed conductors face each other, and an anisotropic conductive adhesive having conductivity in the thickness direction and insulation in the surface direction between these conductors A splice structure of a flexible flat cable, wherein a film is interposed and the FFC conductor is bonded and connected to both surfaces of the anisotropic conductive adhesive film in the thickness direction. Each FFC has the conductor having a rectangular cross section continuous in a strip shape, and a plurality of the conductors are arranged in parallel with a gap and laminated with the insulating film,
The one FFC to be overlapped is for the main line, the other FFC is for the branch line,
In the trunk FFC, the conductors of the plurality of splice connection portions are individually exposed at intermediate positions in the length direction, whereas in the branch FFC, required conductors are individually exposed at one end position in the length direction.
With respect to the intermediate position where the conductor of the main line FFC is exposed, one end of the branch line FFC is positioned in an orthogonal direction or an inclined direction, the exposed conductors are opposed to each other, and the anisotropy is interposed therebetween. The splice structure of the flexible flat cable according to claim 1, wherein the splice structure is connected via a conductive adhesive film.   The flat cable splice structure according to claim 1 or 2, wherein the conductor of the connecting portion that peels and exposes the insulating film in the form of a hole is displaced in the length direction between conductors at adjacent positions.   The anisotropic conductive adhesive film is a film in which conductive metal fibers are oriented in the thickness direction in an insulating resin having adhesiveness, and only the conductors in the thickness direction where both ends of the conductive metal fibers are in contact with each other. The flat cable splice structure according to any one of claims 1 to 3, wherein the flat cable splice structure is electrically conductive.

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