JP2001006774A - Connecting method for flat cable and bus bar and connecting structure formed by the same method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect and reinforce a connecting part of a flat cable with a narrowed electric conductor and a bus bar and to improve insulating property. SOLUTION: On band-shaped bus bars 11 arranged in parallel, an electric conductor 13 of each flat cable 10 is overlapped. From both side surfaces of this overlapped part 14, insulating resin sheets 16, 17 are laminated. Subsequently, a hole part 14b is formed by a drilling. The electric conductor 13 and the bus bars 11 are strongly and closely adhered and fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of connecting a flat cable to a bus bar and a connection structure formed by the method, and more particularly, to a flat cable of a cable reel mounted on a steering device of an automobile and a lead of an external circuit. In connection with a wire via a bus bar, the wire is suitably used for connection between the bus bar and a flat cable.

[0002]

2. Description of the Related Art As shown in FIG. 7, the cable reel has a fixed body 1 fixed to a vehicle body and a movable body 2 attached to a steering wheel and rotatably assembled to the fixed body 1. An annular cable storage chamber is formed, and the flat cable 3 is spirally stored in the cable storage chamber. Both ends in the length direction of the flat cable 3 are connected to one ends of a relay bus bar 5 attached to an inner case 4 fixed to the fixed body 1 and the movable body 2 respectively. The other end of the bus bar 5 is connected to a lead wire 6 of an external circuit, and winds or unwinds the flat cable 3 according to the rotation of the movable body 2.

[0003] As shown in FIG. 8, the flat cable 3 has the conductors 3a arranged side by side by exfoliating the resin films on both sides at the tip end, while the bus bar 5 has a plurality of narrow widths. The insert molding is performed at the time of molding the inner case 4 so as to be fitted and fixed in the grooves provided side by side with the inner case 4. The connection structure of the flat cable 3 and the bus bar 5 is such that the conductor 3a of the flat cable 3 is overlapped on the bus bar 5, then connected by resistance or ultrasonic welding, and then the inner case 4 is covered with the cover 7 to form a connection portion. Is protected.

[0004]

In the above flat cable 3, the number of conductors 3a arranged side by side has increased with the recent increase in the number of circuits.
As the width of “a” becomes narrower, the pitch becomes narrower. In addition, the width and pitch of the bus bar 5 have been reduced accordingly. For this reason, in the conventional connection method such as resistance or ultrasonic welding, there is a problem that it is difficult to reliably weld and connect the narrow and small-pitch objects due to the size of the electrodes and the like. Further, the strength of the conductor 3a and the bus bar 5 itself is reduced due to the above-mentioned narrowing, so that it is no longer possible to reliably protect only by sandwiching the connecting portion between the inner case 4 and the cover 7. Further, since the partition walls 4b between the grooves 4a of the inner case 4 that partition the connection portion are also narrowed, there is a problem that the insulation between the circuits is reduced.

Further, if the strength of the bus bar is reduced due to the narrowing of the bus bar as described above, when the bus bar 5 is insert-molded into the inner case, the bus bar is likely to be damaged, and the fixing position to the inner case is likely to vary. There are also problems. Further, there is a problem that a large cost is required for manufacturing a mold for forming the inner case, and the manufacturing cost is increased.

The present invention has been made in view of the above-mentioned problems, and has as its object to surely protect and insulate a connection portion between a flat cable and a bus bar and to reduce manufacturing costs.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a flat cable in which both surfaces of a plurality of conductors arranged in parallel at intervals are sandwiched by insulating films, The exposed portions of the conductors are peeled off, and these conductors are overlapped with the strip-shaped bus bars arranged side by side, respectively, and the thermoplastic insulation is provided on both surfaces of the entire overlapped portion of the conductors arranged side by side and the bus bars. A resin sheet is disposed, and the insulating resin sheets on both sides are pressed in the approaching direction while heating an upper pressing jig and a lower pressing jig having a pressing surface in which concave portions and convex portions are alternately continuous, thereby performing the above-described process. The recessed part of the fixture makes the superposed conductor and the bus bar adhere to each other, and the insulating resin sheet adheres to the outer surfaces of both sides thereof, and the projecting part of the jig allows the conductor to overlap the bus bar. Provides a method of connecting the flat cable and a bus bar are bonded to the upper and lower insulating resin sheet gap portion.

As described above, the conductor and the bus bar are overlapped, the insulating resin sheets are arranged from both sides, and the insulating resin sheet is brought into close contact with the pressing jig and heated to connect the conductor and the bus bar. In addition, the connection portion can be reinforced and protected by the insulating resin sheet, and the conventionally used inner case and cover can be eliminated. Thereby, the cost required for molding the inner case and the like can be reduced. Further, since the insulating resin sheet can be formed by cutting to a required size in accordance with the number of conductors and bus bars, it can easily cope with an increase in conductors and the like accompanying an increase in the number of circuits.

Further, the above-mentioned insulating resin sheet can be brought into close contact only by using upper and lower pressing jigs and the like, so that an expensive resistor or ultrasonic welding machine is not required, and the cost for these facilities can be reduced. Further, since the upper and lower pressing jigs have a pressing surface in which concave portions and convex portions are alternately continuous, an insulating resin sheet is positioned in a gap between a conductor and a bus bar in which the convex portions are juxtaposed. By pressing,
The sheet enters the gap, and mutual interference between the conductors arranged side by side can be prevented. As the insulating resin sheet, a thermoplastic insulating resin sheet such as polyethylene terephthalate (PET) having a thickness of about 70 μm is suitably used. Further, an adhesive may be used in combination for bonding the sheets.

Further, in the present invention, it is preferable that after the primary fixing by the jig, a secondary fixing by punching, embossing, or caulking with a rivet is performed from the outer surface of the insulating resin sheet. . In this way, by subjecting the conductor and the bus bar to close contact with the insulating resin sheet, and further performing the secondary fixing process such as the above-mentioned boring process, the conductor can be more reliably joined to the bus bar. Specifically, by pressing or the like, burrs are generated inside the holes formed by piercing the conductor and the bus bar from above the insulating resin sheet, and the burrs lock the conductor and the bus bar. Firmly fixed.

Further, as described above, by embossing the insulating resin sheet from above, the conductor and the bus bar are deformed into a corrugated shape or the like, so that they are more strongly engaged. Furthermore, a rivet is inserted into a hole communicating with the conductor and the bus bar, and the rivet is crimped, so that the joint can be further firmly joined. In addition, laser welding may be used in addition to the connection described above.

Further, the present invention provides a connection structure between a flat cable formed by the above-described connection method and a bus bar. The required connection strength can be maintained by the flat cable and bus bar connection structure formed by the above method,
Also, reliability between circuits can be secured.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B show a connection structure of the first embodiment between a flat cable 10 of the cable reel shown in FIG. 8 and a bus bar 11 for relay.
The flat cable 10 is formed by sandwiching both surfaces of a plurality of conductors 13 arranged side by side at a required interval with an insulating film, and the insulating film at the end is peeled off from both surfaces to expose the conductors 13. are doing. These exposed conductors 13 are superimposed on the strip-shaped bus bars 11 arranged side by side, and the insulating resin sheets 1 are provided on both surfaces of this portion.
The holes 6 and 17 are attached to each other, and a hole is formed by punching.

The connection structure between the conductor 13 and the bus bar 11 is formed by the connection method shown in FIGS. 2A, 2B and 2C. The bus bar 11 is formed by connecting the ends of the plurality of bus bars 11 with a carrier 11a in a state where the bus bars 11 are spaced at a required interval. The exposed conductor 13 of the flat cable 10 is overlaid on the upper surface of the bus bar 11. The bus bar 11 may be formed by insert molding in the same manner as in the related art, except for the connection portion with the conductor 13.

In the overlapping portion 14 of the conductor 13 and the bus bar 11, insulating resin sheets 16 and 17 are disposed from both sides in the vertical direction. The insulating resin sheets 16 and 17 are preferably made of thermoplastic resin. In this embodiment, polyethylene terephthalate (PET) or the like having a thickness of about 70 μm is used. It is formed by cutting.

The insulating resin sheet 1 arranged as described above
6 and 17 are bonded to the overlapping portion 14 by an upper pressing jig 26 and a lower pressing jig 27 shown in FIG. The upper pressing jig 26 is formed of a metal having required rigidity and thermal conductivity, and has a lower surface provided with a pressing surface in which concave portions 26a and convex portions 26b are alternately continuous. The pitches of the concave portions 26a and the convex portions 26b correspond to the pitches of the conductors 13 and the bus bars 11 arranged in parallel. The lower pressing jig 27 is also formed in the same manner as the upper pressing jig 26,
It has a pressing surface in which the projections 7a and the projections 27b are alternately continued.

The upper pressing jig 26 and the lower pressing jig 27
As shown in FIG. 2 (C), in the heated state, the insulating resin sheets 16 and 17 are pressed in a direction in which the insulating resin sheets 16 and 17 are brought into close contact with each other to perform the primary fixing processing of the overlapping portion 14. ing. Due to the above pressing, the recesses 26a and the recesses 27a bring the conductor 13 and the bus bar 11 into close contact with each other,
Further, the insulating resin sheet 1 is pressed by the heated jig.
Reference numerals 6 and 17 have flexibility, conform to the shape of the overlapping portion 14, and are in close contact with the outer surfaces on both sides. In addition, the convex portions 26b and the convex portions 27b adhere the upper and lower insulating resin sheets 16 and 17 in close contact with each other in the gaps 14a between the conductors 13 and the bus bars 11 by the above-described pressing. Note that an adhesive may be applied to the bonding surfaces of the insulating resin sheets 16 and 17 and bonded together with an adhesive force.

By the above-mentioned bonding, each of the conductors 13
And the entire periphery of the overlapping portion 14 of the bus bar 11 is laminated with the insulating resin sheets 16 and 17,
Even if the width of the conductor 13 and the bus bar 11 is small and the strength is insufficient, the rigidity can be supplemented. In addition, since the insulating resin sheets 16 and 17 also exist in the gaps 14a between the adjacent conductors 13 and the bus bars 11, short circuits in the circuit due to mutual interference and the like can be reliably prevented.

Next, as shown in FIG. 3, as a secondary fixing process, using a press machine or the like having a die 30 for punching, the overlapped portion 14 having been subjected to the primary fixing process is used as an insulating resin sheet. Drilling is performed by punching from the outer surfaces of 16 and 17.

As shown in FIG. 1B, a hole 14b is formed in the overlapping portion 14 by the above-described drilling, and the conductor 13 and the bus bar 11 are firmly adhered and fixed.
Specifically, by punching out the mold 30, the insulating resin sheet 16 on the upper surface is drawn into the hole portion 14b to be formed, and the conductor 13 generates burrs 13a.
The burrs 13a are inserted into the bus bar 11 side.
When the punched die 30 is pulled out, the insulating resin sheet 17 on the lower surface is also drawn into the hole 14b.

As described above, the overlapped portions 14 on which the primary and secondary fixing processes have been performed are the insulating resin sheets 16 and 17.
The inner surfaces of the upper and lower portions of the holes 14b formed by the perforation process are covered with insulating resin sheets 16 and 17, respectively.

The secondary fixing process may be omitted if the conductor 13 and the bus bar 11 can be securely adhered to each other by bonding the insulating resin sheets 16 and 17 in the primary fixing process. Further, in the case of the above-mentioned primary fixing processing, in order to increase the contact area and the like and further bring the conductor 13 into close contact with the bus bar 11, as shown in FIGS. In a state where the bus bar 11 is folded in two, the bus bar 11 may be overlapped on the upper surface of the bus bar 11, and the insulating resin sheets 16 and 17 may be bonded together after the bus bar 11 is sandwiched between the conductors 13 folded in two. You may.

Also, a hole is drilled in the bus bar 11 at the stage of the pre-process of the secondary fixing and the like, and only the insulating resin sheets 16 and 17 and the conductor 13 are drilled in the secondary fixing. In this manner, the overlapping portion 14 may be easily punched, and the burrs 13 a of the conductor 13 may be more easily inserted into the bus bar 11. Also,
In order to enhance the adhesion between the conductor 13 and the bus bar 11,
The contact between the conductor 13 and the bus bar 11 may be joined by laser welding or the like from the hole 14b.

FIGS. 5A and 5B show a connection structure of the conductor 13 'of the flat cable 10' and the overlapping portion 14 'of the bus bar 11' formed by the connection method of the second embodiment. . The primary fixing process of the overlapping portion 14 'is performed in the same manner as in the first embodiment. In the secondary fixing process, embossing is performed instead of the boring process.

The embossing is performed by pressing the corrugated pressing surface 30.
The molds 30 ′ and 31 ′ having a ′ and 31 a ′ are pressed by using a pressing machine or the like from both sides of the overlapping portion 14 ′. In the embossed overlapping portion 14 ′, the conductor 13 ′ and the bus bar 11 ′ are plastically deformed in a wave-like manner and are locked to each other, and are firmly adhered and fixed.

FIGS. 6A and 6B show the connection structure of the conductor 13 "of the flat cable 10" and the overlapping portion 14 "of the bus bar 11" formed by the connection method of the third embodiment. . The overlapping portion 14 ″ is processed in the same manner as in the first embodiment until the secondary fixing process, and
b "is formed. The rivet 3 is formed in the hole 14b".
5 "is inserted, the tip 35a" is caulked to form a tightening head 35c ", and the conductor 13" and the bus bar 11 "are further firmly adhered and fixed. The rivet 3 described above.
5 ″ is made of a material having low conductivity, such as aluminum or brass.
This prevents the occurrence of a short circuit or the like from the head 35b "of the rivet 35" exposed from 7 ".

[0027]

As is apparent from the above description, according to the present invention, since the both sides of the superposed portion of the conductor of the flat cable and the bus bar are laminated with the insulating resin sheet, the superposed portion can be reinforced. Insulation can be enhanced and protected. In particular, even if the conductors and bus bars of the flat cable are thin and have a small pitch, even if the strength of these overlapping portions is reduced, the required strength can be maintained by laminating the insulating resin sheet, and the insulating resin sheet is heated. Since it is bonded with a jig having irregularities in a state of having provided flexibility, it can also enter gaps of a small-pitch overlapping portion and reliably maintain insulation.

Further, since the insulating resin sheet can be formed by cutting into a required shape and size in accordance with the number of circuits in the overlapping portion and the like, the number of circuits can be easily increased or changed. In addition, since an expensive resistor or an ultrasonic welding machine or the like is not used for tightly fixing the conductor and the bus bar, the cost of these facilities can be reduced.

Further, when it is desired to enhance the close contact between the conductor and the bus bar, in the state of being laminated with the insulating resin sheet as described above, drilling, embossing, caulking with rivets, and laser welding are performed. By that
A more strongly connected structure can be formed.

[Brief description of the drawings]

1A and 1B show a connection structure of a first embodiment of a flat cable and a bus bar of the present invention, wherein FIG. 1A is a perspective view and FIG.
FIG. 2 is a sectional view taken along line AA of FIG.

FIGS. 2A to 2C are diagrams showing a connection method of a primary fixing process.

FIG. 3 is a cross-sectional view showing a connection method of secondary fixing processing.

FIGS. 4A and 4B are side views showing modified examples of the superposition of a conductor and a bus bar.

FIGS. 5A and 5B are diagrams illustrating a connection method according to a second embodiment.

FIGS. 6A and 6B are diagrams illustrating a connection method according to a third embodiment.

FIG. 7 is an exploded perspective view of the cable reel.

FIG. 8 is an enlarged exploded perspective view of a conventional connecting portion between a flat cable and a bus bar.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Flat cable 11 Bus bar 13, 13 ', 13 "Conductor 14, 14', 14" Overlapping part 16, 17 Insulating resin sheet

Claims (3)

[Claims] 1. A part of a flat cable in which both surfaces of a plurality of conductors arranged in parallel at intervals are sandwiched by insulating films, and portions in which the insulating films on both surfaces are peeled to expose the conductors are provided. The body is overlapped with a strip-shaped bus bar arranged side by side, and a thermoplastic insulating resin sheet is arranged on both sides of the entire overlapped portion of the conductor and the bus bar arranged side by side, and the recess and the protrusion are alternately continuous. Pressing the insulating resin sheets on both sides in the approaching direction while heating the upper pressing jig and the lower pressing jig having the holding surface, and bringing the superposed conductor and busbar into close contact with each other by the concave portion of the jig At the same time, the insulating resin sheets are brought into close contact with the outer surfaces of both sides, and the upper and lower insulating resin sheets are bonded to each other in the gap between the overlapping portion of the conductor and the bus bar by the convex portion of the jig. Method of connecting the Ttokeburu and the bus bar. 2. The flat according to claim 1, wherein after the primary fixing by the jig, a secondary fixing by punching, embossing, or caulking with a rivet is performed from the outer surface of the insulating resin sheet. How to connect cables and busbars. 3. A connection structure between a flat cable and a bus bar formed by the connection method according to claim 1.