JPH0355008B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a coaxial flat cable by arranging a plurality of coaxial cores in parallel and fusing their outer sheaths to each other.

(Prior art) In electronic computers, etc., in order to increase the wiring density, highly foamed fluoroplastics, polyethylene, polypropylene, etc. are used as the insulator 3 between the center conductor 1 and the outer conductor 2, as shown in FIG. outer conductor 2
A coaxial core 5 is provided with a round outer sheath 4 on its outer periphery.
A coaxial flat cable is used in which multiple cables are connected in a flat configuration.

In the case of this shape, the outer sheathing 4 of the coaxial cores 5 can be connected by heating and fusing the troughs 6 using a heat roll or the like, but in this case, the insulator 3 is crushed by heating and pressurization. It was difficult to achieve the desired characteristics. For this reason, bonding with adhesive was used.

However, although the method of connection by adhesion is suitable for the outer covering 4 which is easily adhered such as polyvinyl chloride, there is a problem in terms of adhesive strength when using polyethylene, fluorocarbon resin, or the like.

For this purpose, the outer coating 4 is made to have a quadrilateral (rectangular) cross section as shown in FIG. They are melted and fused together to connect them. In the case of such a method, for example, it is possible to apply fusion bonding intermittently in the longitudinal direction of the cable.

(Problem to be solved by the invention) However, the outer covering 4 as shown in FIG.
If the insulator 3 has a shape of There is a problem in that the coaxial core 5 is crushed and the transmission characteristics of the coaxial core 5 change. In particular, when the insulator 3 is made of foamed resin such as foamed polyethylene or foamed polypropylene, if it collapses during the fusion process and the foaming rate decreases, the characteristic impedance and propagation speed, which are important for transmission characteristics, will decrease. There was a problem with the decline.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a coaxial flat cable that can prevent the insulator from collapsing even when the insulator is made of foamed resin, and can fuse the outer sheath.

(Means for solving the problems) The means of the present invention for achieving the above object are as follows:
The present invention will be explained with reference to FIGS. 1 to 4, which correspond to embodiments. In the present invention, an insulator 3 and an outer conductor 2 are sequentially provided around the outer periphery of a center conductor 1, and a thermoplastic resin is coated in a cross section as an outer coating 4 thereon. A plurality of extruded and coated coaxial cores 5 are arranged in parallel so that they are quadrilateral,
In the method for manufacturing a coaxial flat cable in which the outer sheathing 4 of each of the coaxial cores 5 is heat-fused to each other, a welding protrusion is provided on the edge of the upper and lower surfaces of the outer sheathing 4 of each of the coaxial cores 5. 8 are provided respectively, and the respective fusion protrusions 8 are melted and fused to each other during heat fusion.

(Function) As described above, when the fusion protrusions 8 are provided on the edges of the upper and lower surfaces of the outer sheath 4 of each coaxial core 5, and the fusion protrusions 8 are heated and melted to be fused to each other,
Welding can be performed while avoiding heating of the insulator 3 as much as possible and also avoiding applying pressure to the insulator 3 as much as possible.

(Example) Examples of the present invention will be described in detail below with reference to the drawings. 1 and 2 show a first embodiment of the present invention. In this embodiment, welding protrusions 8 made of the same material are provided vertically along each edge of the upper and lower surfaces of the quadrilateral outer covering 5 of each coaxial core 5, and the coaxial cores 5 are arranged in a plurality of strips. The coaxial cores 5 are arranged in parallel and passed between heating rolls 7 as shown in FIG. 7, for example, and the respective welding protrusions 8 are heated and melted and crushed to be fused to each other to form coaxial cores 5 as shown in FIG. Connect each other to obtain a coaxial flat cable.

In this way, heating and pressurization will be performed at both ends of the outer sheathing 4 in the width direction away from the position of the insulator 3, and the heating and pressurization of the insulator 3 will be avoided as much as possible for connection. can be done.

Experimental example Center conductor 1: 7 strands of 0.08 mmφ tinned annealed copper wire Insulator 3: Extruded foamed polyethylene that has been expanded by about 60% to an outer diameter of about 1.6 mm Covering Outer conductor 2: 0.08 mmφ tin wire Approximately 55 pieces of annealed copper wire
External coating 4: Extruded and coated with polyvinyl chloride to a width of about 2.5 mm and a thickness of about 2.2 mm, with fusing protrusions 8 protruding from both upper and lower edges. With a similar structure, the characteristic impedance is approximately 90Ω.
20 coaxial cores 5 were lined up side by side and passed between heating rolls 7, and the welding protrusions 8 were melted and connected to each other to produce a coaxial flat cable in which the center conductor 1 was approximately 2.5 mm apart.

In this manufacturing method, the part of the outer coating 4 corresponding to the insulator 3 is not heated or pressurized significantly, so the insulator 3 does not melt or collapse, and the characteristic impedance is approximately 90Ω. There was no change.

FIG. 3 shows a second embodiment of the invention. This embodiment shows an example in which welding protrusions 8 are laterally provided on only one edge of each of the upper and lower surfaces of the outer sheath 4 of each coaxial core 5 in correspondence with the upper and lower surfaces. In this embodiment, the fusion protrusion 8 is heated and melted to be fused to the mating outer covering 4,
Obtain a coaxial flat cable. Note that 9 is a drain line attached to the external conductor 2.

FIG. 4 shows a third embodiment of the present invention. In this embodiment, a plurality of coaxial cores 5 arranged in parallel are provided with non-fused parts 10 and fused parts 11 intermittently in the longitudinal direction. They were fused together to produce a coaxial flat cable.

When the non-fused portions 10 and the fused portions 11 are provided alternately in this manner, the flexibility of the coaxial flat cable is improved and installation becomes easier.

(Effects of the Invention) As explained above, in the present invention, welding protrusions are provided on the edges of the upper and lower surfaces of the quadrilateral outer covering to fuse adjacent outer coverings to each other.
Connection can be performed while avoiding heating and pressurizing the insulator as much as possible. Therefore, it is possible to prevent the insulator from collapsing and to manufacture a coaxial flat cable while avoiding deterioration of the transmission characteristics of each coaxial core.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of each coaxial core used in the first embodiment of the present invention, FIG. 2 is a cross-sectional view of a coaxial flat cable manufactured by the method of the present invention, and FIG. A cross-sectional view of each coaxial core used in Example 2,
Fig. 4 is a plan view of a coaxial flat cable manufactured according to the third embodiment of the present invention, Fig. 5 is a cross-sectional view of a conventional coaxial flat cable using a round coaxial core, and Fig. 6 is a conventional coaxial flat cable. A cross-sectional view of a quadrilateral coaxial core,
FIG. 7 is a side view of the heat fusion process. DESCRIPTION OF SYMBOLS 1... Center conductor, 2... Outer conductor, 3... Insulator, 4... Outer covering, 5... Coaxial core, 7... Heating roll, 8... Welding protrusion.

Claims (1)

[Claims] 1 An insulator and an outer conductor are sequentially placed around the outer periphery of a central conductor, and a thermoplastic resin is extruded and coated as an outer coating thereon so that a plurality of coaxial cores are arranged in parallel, and each of the coaxial cores is arranged in parallel. In the method of manufacturing a coaxial flat cable in which the outer sheathing of each of the coaxial cores is formed by heat-sealing each other, welding protrusions are provided on the edges of the upper and lower surfaces of the outer sheath of each coaxial core, and during heat-sealing, A method of manufacturing a coaxial flat cable, characterized in that each of the fusion protrusions is melted and fused to each other.