JP2001250441A - Coaxial cable and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coaxial cable with a braided metal shielding conductor layer impregnated with a molten metal to improve both lubrication of an inner circumferential face of the metal plated layer and close contact with an outer periphery of an insulated cable, and method of manufacturing the cable. SOLUTION: A coaxial cable is achieved by a process comprising the steps of coating an outer periphery of core conductor with an insulating layer to form an insulated cable, coating the insulated cable with a braided metal shielding conductor layer, and passing the cable through a coating molten metal to impregnate the molten metal into the braided metal shielding conductor layer. The braided metal shielding conductor layer is achieved by braiding one or more flux-containing solder or tin wire 6 added to the insulated cable W to form an intermediate cable 11, which is passed through a molten metal plating solution to form a metal coat. Thus the coaxial cable is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a coaxial cable and a coaxial cable, and more particularly, to improving the smoothness of an inner peripheral surface of a metal plating layer in which a metal braided shielding conductor layer is impregnated with a molten metal. The present invention relates to a method for manufacturing a coaxial cable having improved adhesion to an insulated cable and a coaxial cable.

[0002]

2. Description of the Related Art As a coaxial cable for use in a high-frequency band having excellent electrical characteristics such as reflection and attenuation in a high-frequency band, copper or aluminum or the like is coated on the outer periphery of an insulated cable in which an insulating layer is coated on the outer periphery of a center conductor. BACKGROUND ART A semi-rigid coaxial cable in which a metal pipe is covered coaxially is known. However, the semi-rigid coaxial cable using the metal pipe has a problem that the manufacturing cost is high and the wiring work is difficult due to poor flexibility.

[0003] Thus, a coaxial cable which is inferior in electrical characteristics such as reflection and attenuation to the semi-rigid type coaxial cable using the above-mentioned metal pipe but has a low manufacturing cost and is flexible is provided on the outer periphery of the center conductor. After coating the outer periphery of the insulated cable with the metal braided shielding conductor layer, the coaxial cable having a metal plating layer formed by impregnating the metal braided shielding conductor layer with the molten metal by passing through a molten metal plating solution is used. Proposed.

FIG. 6 is an explanatory view showing a process of forming a metal braided shielding conductor layer in a method of manufacturing a coaxial cable using the above-mentioned molten metal plating solution. In the previous step, an insulating layer (103 of 7) is formed on the outer periphery of the center conductor (102 of FIG. 7) by common means.
Is drawn out from the supply reel 20 and passes through the guide pulley 21 to enter the die 24.
On the other hand, at the entrance of the die 24, the reel 25 around which the metal conductor wire 14 is wound turns the metal conductor wire 14 by braiding around the insulated cable W, and the metal braid shielding conductor is formed around the outer periphery of the insulated cable W. A layer (104 in FIG. 7) is formed. The intermediate cable 111 having the metal braided shielding conductor layer (104 in FIG. 7) formed on the outer periphery of the insulated cable W is taken up by the take-up capstan 22 and taken up by the take-up reel.

FIG. 7 is a cross-sectional view of the intermediate cable 111. In the intermediate cable 111, the metal braided shielding conductor layer 104 is in close contact with the outer periphery of the insulated cable W.

FIG. 8 is an explanatory view showing a process of forming a metal plating layer in the method of manufacturing a coaxial cable using the above-described hot-dip metal plating. The intermediate cable 111 is led out from the supply reel 51, is coated with flux by a flux coating device 52, passes through a guide pulley 53A, and is introduced into a molten metal plating solution 55 in a molten metal plating tank 54,
It is led out of the molten metal plating solution 55 through the guide pulley 53B in the molten metal plating tank 54, is adjusted to a required plating thickness through a plating solution drawing die 56 arranged on the molten metal plating solution 55, and is cooled. Cooled by the device 57, the coaxial cable 101 is formed into a coaxial cable 101, and is wound on a take-up reel 58 via a guide pulley 53 </ b> C.

FIG. 9 is a cross-sectional view of a coaxial cable 101 obtained by the above-described conventional method of manufacturing a coaxial cable using hot-dip metal plating. This coaxial cable 101 has a structure in which a metal plating layer 105 in which a metal braided shielding conductor layer 104 is impregnated with a molten metal is formed on the outer periphery of an insulated cable W in which an insulator layer 103 is coated on the outer periphery of a center conductor 102. .

FIG. 10 is an illustration of transmission attenuation characteristics and transmission reflection attenuation characteristics of the coaxial cable 101. A coaxial cable 101 having a sample length of 1 m was prepared, and the reflection / attenuation characteristics were measured in a high frequency band of 0.045 GHz to 18 GHz using a network analyzer. The attenuation and reflection peaks, which are considered to be affected by the winding pitch of the metal braided shielding conductor layer 104, have a transmission frequency of 10 GHz
Was seen nearby. In addition, 0.045 GHz to 18 GHz
, The reflected voltage standing wave ratio in the high frequency band was 1.4 times.

[0009]

In the above-described conventional method for manufacturing a coaxial cable using hot-dip metal plating, as shown in FIG. 104 is in close contact. Therefore, for example, a molten metal plating solution 55 of 260 ° C.
When the intermediate cable 111 is introduced therein, the insulating layer 103 made of a resin material undergoes a large thermal expansion, so that the insulating layer 103 bites into the metal braided shield conductor 104. Then, the molten metal cannot be impregnated to the inside of the metal braided shield conductor 104, and when the insulator layer 103 is cooled to the original size, as shown in FIG. The braided shielding conductor layer 104 is exposed and uneven, and a space is created. However, if the inner peripheral surface of the metal plating layer 105 through which the high-frequency current mainly flows is uneven and has a space, there is a problem that high-frequency characteristics are deteriorated. For example, as shown in FIG.
Attenuation and reflection peaks, which are considered to be affected by the winding pitch, appear near the transmission frequency of 10 GHz.
There is a problem that it is difficult to use in a band including z. Further, there is a problem that the metal plating layer 105 is easily removed because the adhesion between the insulated cable W and the metal plating layer 105 is poor. Note that the present inventors have disclosed in Japanese Patent Application No. 11-308.
No. 863 has been filed for the present invention.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned various problems of the prior art, and has improved the smoothness of the inner peripheral surface of a metal plating layer in which a metal braided shielding conductor layer is impregnated with a molten metal. It is another object of the present invention to provide a method of manufacturing a coaxial cable and a coaxial cable having improved adhesion to an outer periphery of an insulated cable.

[0011]

According to a first aspect of the present invention, an insulated cable having a center conductor covered with an insulating layer is coated with a metal braided shielding conductor layer and then passed through a molten metal plating solution. In a method of manufacturing a coaxial cable in which a metal plating layer is formed by impregnating a molten metal into the metal braided shielded conductor layer, the braiding step of coating the metal braided shielded conductor layer includes the steps of: The present invention relates to a method of manufacturing a coaxial cable in which one or more intruded wires are attached and braided. In the method of manufacturing a coaxial cable according to the first aspect, the insulated cable is braided with one or more flux-containing solder wires or flux-containing tin wires (hereinafter abbreviated as flux-containing solder wires). When the intermediate cable is immersed in the molten metal plating solution, the flux-filled solder wire melts into the molten metal plating solution, so that there is a spatial margin between the insulating cable and the metal braided shielding conductor layer. Therefore, even if the insulator layer expands, the insulator layer does not penetrate to the inside of the metal braided shield conductor layer. In Japanese Patent Application No. 11-308863, a solder wire or a tin wire is used. However, in the present invention, since a flux-containing solder wire is used, the wettability is improved. Therefore, the molten metal is impregnated into the inside of the metal braided shielding conductor layer, so that no irregularities or spaces are generated on the inner peripheral surface of the metal plating layer. Therefore, a coaxial cable having excellent transmission signal reflection / attenuation characteristics can be obtained. In addition, the metal plating layer hardly comes off.

As a second aspect, the present invention provides a coaxial cable manufactured by the method for manufacturing a coaxial cable according to the first aspect, wherein the diameter of the coaxial cable is reduced using a die or a swaging machine. There is a method of manufacturing a coaxial cable in which a space between metal plating layers is removed to provide high adhesion. In the method of manufacturing a coaxial cable according to the second aspect, the diameter of the coaxial cable is reduced by using a die or a swaging machine, and a space between the insulator layer and the metal plating layer is removed to provide high adhesion. Therefore, it is possible to obtain a coaxial cable having more excellent transmission signal reflection / attenuation characteristics. In addition, the metal plating layer hardly comes off.

According to a third aspect of the present invention, a metal plating layer is formed by impregnating a metal braided shielding conductor layer with a molten metal on an outer periphery of an insulated cable in which an outer periphery of a center conductor is covered with an insulator layer. In a coaxial cable obtained by the method for manufacturing a coaxial cable according to the first aspect or the second aspect,
In the coaxial cable, the inner peripheral surface of the metal plating layer is smooth and is in close contact with the outer periphery of the insulated cable. In the coaxial cable according to the third aspect, the inner peripheral surface of the metal plating layer is smooth and is in close contact with the outer periphery of the insulated cable.
The transmission signal has excellent reflection / attenuation characteristics. Also,
The metal plating layer hardly comes off.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The contents of the present invention will be described below in more detail with reference to an embodiment shown in the drawings. Note that the present invention is not limited by this.

First Embodiment FIG. 1 is an explanatory view showing a process of forming a metal braided shielding conductor layer in a method of manufacturing a coaxial cable according to a first embodiment of the present invention. The center conductor (Fig. 2)
The insulating cable W whose outer layer is covered with an insulating layer (103 in FIG. 2) is led out from the supply reel 20, passes through the guide pulley 21, and enters the die 24. The flux-filled solder wire 6 is led out from the solder wire supply reel 26 and enters the die 24 along the insulating cable W. On the other hand, at the entrance of the die 24, the reel 25 around which the metal conductor wire 14 is wound rotates around the insulated cable W and the flux-cored solder wire 6, so that the metal conductor wire 14
To form a metal braid shielding conductor layer (104 in FIG. 2) on the outer periphery of the insulated cable W and the flux-cored solder wire 6. The intermediate cable 11 in which the metal braid shielding conductor layer (104 in FIG. 2) is formed on the outer periphery of the insulated cable W and the flux-cored solder wire 6 is taken up by the take-up capstan 22 and taken up by the take-up reel 23.

FIG. 2 is a schematic view for explaining the intermediate cable 11, and FIG.
1 is a cross-sectional view, and FIG.
FIG. In the intermediate cable 11, the outer periphery of the insulated cable W and the flux-cored solder wire 6 is covered with a metal braided shielding conductor layer 104. The flux-filled solder wire 6 has a structure in which a flux 6b is filled inside a thin pipe-shaped linear body 6a made of solder or tin.

FIG. 3 is an explanatory view showing a process of forming a metal plating layer in the method of manufacturing a coaxial cable according to the first embodiment of the present invention. The intermediate cable 11 is led out from the supply reel 51 and is applied with a flux by a flux applying device 52. Next, the intermediate cable 11 coated with the flux passes through the guide pulley 53A, is introduced into the molten metal plating solution 55 in the molten metal plating tank 54, passes through the guide pulley 53B in the molten metal plating tank 54, and It is derived from the liquid 55. During this time, the metal braided shielding conductor layer 104 of the intermediate cable 11 is impregnated with the molten metal. At this time, the flux-filled solder wire 6 quickly dissolves in the molten metal plating solution 55, so that the metal-braided shielding conductor layer 104 has a space for the flux-filled solder wire 6. Therefore, even when the insulating layer 103 made of a resin material thermally expands, the insulating layer does not penetrate to the inside of the metal braided shielding conductor layer 104.
Therefore, the molten metal is impregnated into the inside of the metal braided shielding conductor layer 104, so that no irregularities or spaces are generated on the inner peripheral surface of the metal plating layer (105 in FIG. 4). Next, the molten metal plating solution 5
The plating solution is adjusted to a required plating thickness through a plating solution drawing die 56 disposed on the cooling solution 5, cooled by a cooling device 57, reduced in diameter by a reduced diameter die 60, and formed into a coaxial cable 1. The coaxial cable 1 is wound on a take-up reel 58 via a guide pulley 53C.

FIG. 4 shows a coaxial cable 1 obtained by the method of manufacturing a coaxial cable according to the first embodiment of the present invention.
FIG. This coaxial cable 1 has a central conductor 10
2, a metal plating layer 105 in which a metal braided shielding conductor layer 104 is impregnated with a molten metal is formed on the outer periphery of an insulated cable W in which an insulator layer 103 is coated on the outer periphery. Since the molten metal is impregnated into the inside of the metal braided shielding conductor layer 104, no irregularities or spaces are generated on the inner peripheral surface of the molten metal plating layer 105, and a coaxial cable having excellent transmission signal reflection / attenuation characteristics is obtained. Further, the metal plating layer 105 is hardly removed.

As a specific example, the center conductor 102 is a silver-plated copper-clad steel wire having an outer diameter of 0.91 mm.
Is a 0.99-mm-thick extruded and coated tetrafluoroethylene resin. The flux-filled solder wire 6 has a flux 6b inside a small-diameter pipe-like linear body 6a made of solder or tin.
Is filled and has an outer diameter of 0.3 mm.
Reference numeral 04 denotes a 16-strand holding of 7 tinned soft copper wires having an outer diameter of 0.1 mm. The intermediate cable 11 has an outer diameter of 3.5 mm. The molten metal plating solution 55 is a molten tin plating solution having a solution temperature of 260 ° C. The passage time in the molten metal plating solution 55 is about 6 seconds. The drawing die 56 has an inner diameter of 3.55 mm and is finished to a finished plating outer diameter of 3.55 mm. The cooling device 57 is air-cooled at an ambient temperature of 10 ° C. The reduced diameter die 60 has an inner diameter of 3.47 mm. In addition, the first
In the embodiment, the flux applied to the intermediate cable 11 is applied using the flux applying device 52,
The flux applying device 52 may be omitted depending on conditions, such as when a plurality of flux-containing solder wires 6 are used.

FIG. 5 is an illustration of transmission attenuation characteristics and transmission reflection attenuation characteristics of the coaxial cable 1. Sample length 1m
Was prepared, and the reflection / attenuation characteristics were measured in a high frequency band of 0.045 GHz to 18 GHz using a network analyzer. As a result, attenuation and reflection peaks, which are considered to be affected by the winding pitch of the metal braid shielding conductor layer 104, are eliminated. Also,
The reflected voltage standing wave ratio in the high frequency band of 0.045 GHz to 18 GHz was 1.1 times or less. In the manufacturing method according to the first embodiment, a coaxial cable was manufactured without reducing the diameter by the diameter reducing die 60, and the transmission attenuation characteristics and the transmission reflection attenuation characteristics were measured (not shown). However, compared to the coaxial cable according to the first embodiment, there was no significant difference, and the result was good.

The flux-filled solder wire 6 may have a circular cross section, but may have an elliptical cross section, a rectangular cross section, or a square cross section depending on the application. Further, the solder material of the flux-containing solder wire 6 may be a tin-lead alloy having a melting point of 350 ° C. or less, other metal wires or metal alloy wires, and the flux may be a general fat. In any case, it has been experimentally found that the cross-sectional area of the flux-cored solder wire 6 is preferably 0.0008 to 0.070 times the cross-sectional area of the insulated cable W.

[0022]

According to the method for manufacturing a coaxial cable and the coaxial cable of the present invention, when an intermediate cable made by braiding with one or more flux-filled solder wires is immersed in a molten metal plating solution, a flux Since the solder wire quickly melts into the molten metal plating solution, a space is created between the insulated cable and the metal braided shielding conductor layer. Therefore, even if the insulator layer expands, the insulator layer does not penetrate to the inside of the metal braided shield conductor layer. Therefore, since the molten metal penetrates into the inside of the metal braided shielding conductor layer, no irregularities or spaces are formed on the inner peripheral surface of the metal plating layer, and the smoothness of the inner surface of the metal plating layer is improved. Accordingly, it is possible to obtain a coaxial cable having excellent reflection / attenuation characteristics of a high-frequency signal, and it is difficult for the metal plating layer to come off.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a process of forming a metal braided shielding conductor layer in a method of manufacturing a coaxial cable according to a first embodiment of the present invention.

FIGS. 2A and 2B are schematic views for explaining an intermediate cable according to the first embodiment of the present invention. FIG. 2A is a cross-sectional view of the intermediate cable, and FIG. FIG.

FIG. 3 is an explanatory view showing a process of forming a metal plating layer in the method of manufacturing a coaxial cable according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view of the coaxial cable according to the first embodiment of the present invention.

FIG. 5 is a chart showing attenuation characteristics and a reflected voltage standing wave ratio of the coaxial cable according to the first embodiment of the present invention.

FIG. 6 is an explanatory view showing a process of forming a metal braided shielding conductor layer in a conventional method of manufacturing a coaxial cable.

FIG. 7 is a cross-sectional view of a conventional intermediate cable.

FIG. 8 is an explanatory view showing a process of forming a metal plating layer in a conventional method of manufacturing a coaxial cable using hot-dip metal plating.

FIG. 9 is a cross-sectional view of a coaxial cable obtained by a conventional method of manufacturing a coaxial cable using hot-dip metal plating.

FIG. 10 is a chart showing attenuation characteristics and a reflected voltage standing wave ratio of a conventional coaxial cable.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coaxial cable 6 Flux-containing solder wire or flux-containing tin wire 6a Small-diameter pipe-like linear body made of solder or tin 6b Flux 11 Intermediate cable 14 Metal conductor wire 20 Feeding reel 21 Guide pulley 22 Pull-up capstan 23 Winding Reel 24 Dice 25 Reel on which metal conductor wire is wound 26 Flux-in solder wire supply reel 51 Supply reel 52 Flux coating device 53A Guide pulley 53B Guide pulley 53C Guide pulley 54 Molten metal plating tank 55 Molten metal plating solution 56 Plating solution Drawing die 57 Cooling device 58 Take-up reel 60 Reduced diameter die 102 Center conductor 103 Insulator layer 104 Metal braided shielding conductor layer 105 Molten metal plating layer W Insulated cable

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G313 AA10 AB03 AB05 AC03 AD06 AD07 AE08 5G319 FA04 FA10 FC20 5G323 EA01

Claims (3)

[Claims] 1. A metal braided shielding conductor layer is coated on an insulated cable having an outer peripheral layer of a center conductor coated with an insulator layer, and then passed through a molten metal plating solution to impregnate the metal braided shielding conductor layer with a molten metal. In the method of manufacturing a coaxial cable for forming a metal plating layer, in the braiding step of covering the metal braid shielding conductor layer, braiding the insulating cable with at least one flux-containing solder wire or flux-containing tin wire. Characteristic coaxial cable manufacturing method. 2. A coaxial cable manufactured by the method of manufacturing a coaxial cable according to claim 1, wherein the diameter of the coaxial cable is reduced by using a die or a swaging machine to reduce a space between the insulator layer and the metal plating layer. A method for manufacturing a coaxial cable, wherein the coaxial cable is removed to have high adhesion. 3. A metal plating layer is formed by impregnating a metal braided shielding conductor layer with a molten metal on an outer periphery of an insulated cable having an outer periphery of a center conductor covered with an insulator layer. A coaxial cable obtained by a method for manufacturing a coaxial cable, wherein an inner peripheral surface of the metal plating layer is smooth and closely adheres to an outer periphery of the insulated cable.