JP2000048653A - High-speed transmission coaxial cable and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-speed transmission coaxial cable provided with an insulator having a thin skin layer had to peel off, and to provide its manufacturing method. SOLUTION: In this coaxial cable, an insulator 2 covering a central conductor 1 is composed of an insulating layer 2a formed on the periphery of the central conductor 1 and a skin layer 2b formed on the periphery of the insulating layer 2a. Here, the insulating layer 2a is made of a foamed insulating resin having a foaming degree of at least 5%, and the skin layer 2b is formed from a sintered powered resin. Thereby, thickness of the skin layer 2b can be thinned and improve adhesive power compared with a conventional skin layer of melting extrusion type, to obtain the insulator hard to peel off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coaxial cable for high-speed transmission frequently used for high-frequency devices, antenna feed lines, and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Generally, coaxial cables for high-speed transmission, which are often used for high-frequency devices and antenna feed lines, have an insulator,
The outer conductor and the jacket are formed by coating sequentially. As one of the insulators, a foamed layer is formed by extruding and covering an insulating resin foamed on the outer periphery of the center conductor, and then forming the foamed layer. It is known that an insulating resin is melt-extruded on the outer side to reinforce it, or a skin layer is formed by winding an insulating tape.

However, in the case of an insulator having a skin layer formed by melt-extruding and coating an insulating resin, there is an advantage that the outer diameter can be reduced, but the thickness of the skin layer is reduced to 30 μm or less. There was a problem that it was not possible.

On the other hand, in the case of an insulator having a skin layer made of an insulating tape, it takes a long time to wind the tape, and the adhesive is used, so that the tape is easily peeled off. .

Accordingly, the present invention has been devised in order to effectively solve such a problem, and an object of the present invention is to provide a high-speed transmission provided with an insulator having a thin and not easily peelable skin layer. And a method of manufacturing the same.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an insulating layer formed by extruding and covering a foamed insulating resin on the outer periphery of a center conductor, and forming a powdered resin on the outer periphery of the insulating layer. Is electrostatically applied and then sintered to form a skin layer, and thereafter, an outer conductor and a jacket are sequentially formed on the outer periphery of the skin layer.

[0007] The skin layer thus formed can be made much thinner than the conventional melt extrusion coating method, and it is strongly adhered to the insulating layer made of foam. An insulator that does not occur is obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIGS. 1 and 2 show an embodiment of a coaxial cable for high-speed transmission according to the present invention. In FIG. 1, reference numeral 1 denotes a center conductor made of a silver-plated soft copper wire or the like; Is an outer conductor made of a horizontally wound shield wire or the like, which is coated on the outer periphery of the insulator 2.
Is a jacket made of polyvinyl chloride or the like having excellent flame retardancy.

As shown in the figure, the insulator 2 has two layers: a thick insulating layer 2a formed on the outer periphery of the outer conductor 1, and a thin skin layer 2b formed outside the insulating layer 2a. The insulating layer 2a is made of a foamed insulating resin such as PFA (perfluoroalkoxyne), and the one skin layer 2b is made of ETFE (ethylene tetrafluoroethylene).
Etc. are formed from a thin film-shaped sintered body obtained by sintering a powder type resin.

The insulating layer 2a is formed by extruding and covering a foamed insulating resin such as PFA on the outer periphery of the outer conductor 1. One skin layer 2b is formed by coating a powdered resin such as ETFE with the insulating layer. After being electrostatically applied and adsorbed on the outer periphery of 2a, or after being applied in a liquid state, it is formed by sintering.

And, in such an insulator 2,
The thickness of the skin layer 2b can be made thinner than before, and the adhesive strength is further improved, so that it is possible to obtain a high-speed transmission coaxial cable provided with the highly reliable insulator 2 without being easily peeled off. .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS.
A 1.0 mm thick foamed PFA (65% foaming degree) is extruded around the center conductor 1 made of a silver-plated annealed copper wire to form an insulating layer 2a. ETFE powder was electrostatically applied and adsorbed, and sintered at a temperature of 180 to 230 ° C. to form a skin layer 2b.

The skin layer 2b thus obtained is
Compared with the conventional melt-extrusion skin layer, the thickness can be reduced by about 10 μm, and the adhesive layer is firmly formed on the surface of the insulating layer 2a without peeling.

[0015]

In summary, according to the present invention, since a skin layer is formed by sintering a powder of ETFE or the like on the outside of the insulating layer after electrostatically adhering the powder, a conventional melt extrusion type skin layer is formed. Thus, an insulator having a skin layer that is thinner and does not easily peel off can be obtained. as a result,
Excellent effects such as obtaining a more reliable coaxial cable for high-speed transmission without deteriorating the conventional characteristics can be exhibited.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a high-speed transmission coaxial cable according to the present invention.

FIG. 2 is a sectional view showing an embodiment of a high-speed transmission coaxial cable according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 center conductor 2 insulator 2a insulating layer 2b skin layer 3 outer conductor 4 jacket

Claims (4)

[Claims] 1. A coaxial cable for coaxial high-speed transmission in which an outer periphery of a center conductor is sequentially covered with an insulator, an outer conductor, and a jacket, wherein the insulator is formed on the outer periphery of the center conductor, A skin layer formed on the outer periphery of the layer, wherein the insulating layer is made of a foamed insulating resin having a foaming degree of 5% or more, and the skin layer is made of a sintered body of a powder type resin. Coaxial cable for high-speed transmission. 2. The coaxial cable for high-speed transmission according to claim 1, wherein the coating thickness of the skin layer is 30 μm or less. 3. An insulating layer is formed by extruding and covering a foamed insulating resin on the outer periphery of the center conductor. A powdered resin is electrostatically applied on the outer periphery of the insulating layer, followed by sintering to form a skin layer. And
Thereafter, an outer conductor and a jacket are sequentially formed on the outer periphery of the skin layer to form a coaxial cable for high-speed transmission. 4. The method for manufacturing a high-speed transmission coaxial cable according to claim 3, wherein the coating thickness of the skin layer is 30 μm or less.