JPH01294308A - Coaxial cable - Google Patents

Coaxial cable

Info

Publication number
JPH01294308A
JPH01294308A JP12335988A JP12335988A JPH01294308A JP H01294308 A JPH01294308 A JP H01294308A JP 12335988 A JP12335988 A JP 12335988A JP 12335988 A JP12335988 A JP 12335988A JP H01294308 A JPH01294308 A JP H01294308A
Authority
JP
Japan
Prior art keywords
center conductor
insulating layer
coaxial cable
synthetic resin
conductor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP12335988A
Other languages
Japanese (ja)
Inventor
Kosaku Nakano
中野 耕作
Seiichi Nishikawa
西川 清一
Susumu Tsuchiya
進 土屋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujikura Ltd
Original Assignee
Fujikura Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fujikura Ltd filed Critical Fujikura Ltd
Priority to JP12335988A priority Critical patent/JPH01294308A/en
Publication of JPH01294308A publication Critical patent/JPH01294308A/en
Pending legal-status Critical Current

Links

Abstract

PURPOSE:To make it possible to realize not only a specific dielectric constant but also to obtain a coaxial cable of a stable electric property by providing spacers made of an insulating material to maintain the interval at a part of a clearance between a center conductor and an insulating layer. CONSTITUTION:An insulating layer 2 which consists of a foamy synthetic resin is arranged coaxially to a center conductor 1 by plural spacers 3 placed between the insulating layer 2 and the center conductor 1. And the spacers 3 are formed of an insulating synthetic resin, for example, arranged in the direction parallel to the axis of the center conductor 1 placing a specific interval each other along the circumferential direction of the conductor 1 and the insulating layer 2, and they form continuous spaces 4 between the center conductor 1 and the insulating layer 2 in the longitudinal direction of the center conductor 1. As a result, a coaxial cable suitable for the purpose requiring a high transmission speed and with a stable electric property can be manufactured by using a relatively small foaming rate and a stable quality of foamy synthetic resin.

Description

【発明の詳細な説明】 「産業上の利用分野」 本発明は同軸ケーブルに係り、特に、中心導体とシール
ドとの間に発泡性の絶縁層を設けることによって静電容
量の低減を図った同軸ケーブルに関するものである。
Detailed Description of the Invention "Field of Industrial Application" The present invention relates to a coaxial cable, and in particular to a coaxial cable that reduces capacitance by providing a foamed insulating layer between a center conductor and a shield. It's about cables.

「従来の技術」 近年、大型コンピユータ等で使用される通信ケーブルに
おいては、信号の遅延時間をケーブル1メートル当たり
3.6nsec程度に押さえたいといる要求がある。ま
た前記遅延時間は、ケーブルの有する静電容量が信号伝
播速度に下記のように影響することに起因して生じるこ
とが知られている。
"Prior Art" In recent years, there has been a demand for communication cables used in large computers and the like to suppress signal delay time to about 3.6 nsec per meter of cable. Further, it is known that the delay time occurs because the capacitance of the cable affects the signal propagation speed as described below.

すなわち、同軸ケーブルにおける信号伝播速度V [k
m/sea]と比誘電率との間には、関係があるから、
この式より、ケーブルの比誘電率εを1.166(−:
 1.17)以下にすることか要求されており、このε
を実現するには、テトラフロロエチレンエチレン(T 
F E )、濁化エチレンプロピレン(FEP)、テト
ラフロロエチレンルバーフロロアルキルビニル共重合体
(PFA)等の沸素系の発泡性合成樹脂を用い、かつ、
発泡度を80%以上に高めることが必要とされる。
That is, the signal propagation speed V [k
m/sea] and the relative dielectric constant, so
From this formula, the relative dielectric constant ε of the cable is 1.166 (-:
1.17) It is required that ε
To achieve this, tetrafluoroethylene ethylene (T
F E ), using a fluorine-based foamable synthetic resin such as clouded ethylene propylene (FEP), tetrafluoroethylene rubber fluoroalkyl vinyl copolymer (PFA), and
It is necessary to increase the degree of foaming to 80% or more.

「発明が解決しようとする課題」 ところで、上記同軸ケーブルの製造方法の例として、心
線の周囲に発泡性絶縁層を押し出し被覆すること、また
は、発泡性絶縁体からなるテープを心線の周囲に縦添え
もしくは螺旋状に巻回する方法が知られているが、80
%以上もの高い発泡度では、気泡を構成する合成樹脂膜
の厚さが非常に薄くならざるを得ず、部分的に膜が破れ
て気泡が連続し、不均一な発泡状態きなって安定した電
気的特性を得ることができない場合があるという問題が
あった。
"Problems to be Solved by the Invention" By the way, as an example of the method for manufacturing the above-mentioned coaxial cable, a foamed insulating layer is extruded around the core wire, or a tape made of a foamed insulator is coated around the core wire. There are known methods of wrapping vertically or spirally, but 80
When the degree of foaming is as high as % or more, the thickness of the synthetic resin film that makes up the cells must become extremely thin, and the film may partially break and the cells become continuous, causing an uneven foaming state and becoming stable. There was a problem that electrical characteristics could not be obtained in some cases.

本発明は上記事情に鑑みて提案されたもので、所定の誘
電率を実現することができるとともに、電気的特性の安
定した同軸ケーブルを得ることを目的とするものである
The present invention was proposed in view of the above circumstances, and an object of the present invention is to obtain a coaxial cable that can realize a predetermined dielectric constant and has stable electrical characteristics.

「課題を解決するための手段」 上記目的を達成するため、本発明は、中心導体とこれを
囲むシールドとの間に発泡性樹脂からなる絶縁層を設け
てなる同軸ケーブルにおいて、前記絶縁層の内径を中心
導体より大とするとともに、中心導体と絶縁層との間の
間隙、の一部に、これらの間の間隔を維持する絶縁材料
製のスペーサを設けるようにしたものである。
"Means for Solving the Problems" In order to achieve the above object, the present invention provides a coaxial cable in which an insulating layer made of a foamed resin is provided between a center conductor and a shield surrounding the center conductor. The inner diameter is made larger than that of the center conductor, and a spacer made of an insulating material is provided in a part of the gap between the center conductor and the insulating layer to maintain the gap between them.

「作用」 上記構成であると、中心導体とシールドとの間に、発泡
性樹脂からなる絶縁層のみならず、間隙部分が存在する
こととなって、中心導体とシールドとの間の平均的な誘
電率が小さくなる。
"Function" With the above configuration, not only an insulating layer made of foamed resin but also a gap exists between the center conductor and the shield, resulting in an average gap between the center conductor and the shield. Dielectric constant decreases.

「実施例」 以下、図面を参照して本発明の一実施例を説明する。"Example" Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

第1図および第2図は本発明の一実施例を示すものであ
る。
1 and 2 show one embodiment of the present invention.

図中符号lは中心導体、2は発泡性合成樹脂からなる絶
縁層である。前記絶縁層2は中心導体1の外径より大き
な内径を寸法を有するもので、中心導体lとの間に介在
する複数のスペーサ3によって、中心導体lと軸線を同
じくして配置されている。また前記スペーサ3は、例え
ば絶縁性合成樹脂により形成されるもので、第2図に示
すように中心導体lおよび絶縁層2の周方向に沿ってt
目互に一定に間隔をおいて(図示の場合相互に90’の
間隔をおいて)、かつ中心導体1の軸線と平行な方向に
向けて配置されて、前記中心導体1と絶縁層2との間に
、中心導体lの長さ方向に連続する空間部4を形成して
いる。
In the figure, reference numeral 1 indicates a center conductor, and 2 indicates an insulating layer made of foamable synthetic resin. The insulating layer 2 has an inner diameter larger than the outer diameter of the center conductor 1, and is arranged on the same axis as the center conductor 1 by a plurality of spacers 3 interposed between the insulating layer 2 and the center conductor 1. Further, the spacer 3 is formed of, for example, an insulating synthetic resin, and extends t along the circumferential direction of the center conductor l and the insulating layer 2 as shown in FIG.
The central conductor 1 and the insulating layer 2 are arranged at regular intervals (in the illustrated case, 90' apart from each other) and oriented in a direction parallel to the axis of the central conductor 1. A space 4 that continues in the length direction of the center conductor l is formed between them.

なお、実際に同軸ケーブルとして使用する場合、第1図
鎖線で示すように、前駆絶縁層2の外側には、編組線、
螺旋状に巻かれた金属箔などからなるシールド5と、該
シールド5を覆うシース6とが設けられる。
In addition, when actually used as a coaxial cable, as shown by the chain line in FIG.
A shield 5 made of a spirally wound metal foil or the like, and a sheath 6 covering the shield 5 are provided.

以上のよう構造の同軸ケーブルは、例えば、中心導体l
にスペーサ3を縦添えしつつ発泡性合成樹脂を押し出し
被覆することにより、あるいは、中心導体1にスペーサ
3を縦添えした後、その周囲に発泡性合成樹脂のテープ
を巻回するなどの公知の方法によって容易に製造するこ
とができる。
For example, in a coaxial cable with the above structure, the center conductor l
By extruding and covering the center conductor 1 with a foamable synthetic resin while vertically attaching the spacer 3 to the center conductor 1, or by wrapping a foamable synthetic resin tape around the center conductor 1 after vertically attaching the spacer 3 to the center conductor 1. It can be easily manufactured by this method.

また、押し出し被覆等によって絶縁層を形成する工程の
途中、もしくは、該工程の後に空間部4に圧縮空気など
を充填した内圧加えることにより、絶縁層2の漬れなど
による空間部4の容積の減少を抑制することができる。
In addition, by applying internal pressure filled with compressed air or the like to the space 4 during or after the step of forming the insulating layer by extrusion coating, etc., the volume of the space 4 due to soaking of the insulating layer 2 can be reduced. The decrease can be suppressed.

また、実施例のように空間部4が長さ方向に連続してい
れば、ケーブルの一端部から容易に空間部4全体に内圧
を加えることができる。
Further, if the space 4 is continuous in the length direction as in the embodiment, internal pressure can be easily applied to the entire space 4 from one end of the cable.

そして、上記構造の同軸ケーブルにあっては、空間部4
の存在により、絶縁層2の発泡率を越えて中心導体lと
シールド5との間の空間率(中心導体lとシールド5と
の間の容積に対する絶縁体が存在しない部分の割合)を
高めて誘電率を低減し、所定の電気的特性を満たすこと
ができる。また、空間部4の存在により、絶縁層2の発
泡率をさほど高めることなく所定の誘電率を達成するこ
とができる。
In the coaxial cable with the above structure, the space 4
Due to the presence of the insulating layer 2, the void ratio between the center conductor l and the shield 5 (the ratio of the area where no insulator is present to the volume between the center conductor l and the shield 5) is increased beyond the foaming rate of the insulating layer 2. It is possible to reduce the dielectric constant and satisfy predetermined electrical characteristics. Further, due to the existence of the space 4, a predetermined dielectric constant can be achieved without significantly increasing the foaming rate of the insulating layer 2.

なお、空間率を高める見地から、空間部4の形状を維持
し得る限り、スペーサ3を小さくすることが望ましい。
Note that, from the viewpoint of increasing the porosity, it is desirable to make the spacer 3 small as long as the shape of the space 4 can be maintained.

また、スペーサ3として、発泡性合成樹脂を使用するこ
とも有効である。さらに、スペーサ3の数を多くするほ
ど、外力に耐えて確実に空間部4の形状を維持すること
ができるのは言うまでもないが、その配置については、
できるかぎり中心導体lの円周方向に均一に配置して、
部分的な誘電率の上昇を避けることが望ましい。
It is also effective to use foamable synthetic resin as the spacer 3. Furthermore, it goes without saying that the larger the number of spacers 3, the more it is possible to withstand external forces and maintain the shape of the space 4 more reliably, but regarding their arrangement,
Arrange them as uniformly as possible in the circumferential direction of the center conductor l,
It is desirable to avoid local increases in dielectric constant.

次いで、第3図および第4図は本発明の池の実施例を示
すものである。
Next, FIGS. 3 and 4 show an embodiment of the pond of the present invention.

この実施例は、前記一実施例において複数本設けられて
いたスペーサ3を1本にし、この1本のスペーサ3を第
4図に示すように、中心導体lの周囲に螺旋状に巻き付
けた構造としたものである。
This embodiment has a structure in which the plurality of spacers 3 in the previous embodiment are reduced to one, and this one spacer 3 is wound spirally around the center conductor l as shown in FIG. That is.

このように、螺旋状のスペーサ3を用いることにより、
中心導体lと絶縁層2との間に存在する絶縁体の体積を
低減して空間率をさらに高めることができる。
In this way, by using the spiral spacer 3,
The volume of the insulator existing between the center conductor l and the insulating layer 2 can be reduced to further increase the void ratio.

また、この実施例の同軸ケーブルについても、前記一実
施例の場合と同様の方法により製造することかできる。
Further, the coaxial cable of this embodiment can also be manufactured by the same method as that of the above-mentioned embodiment.

なお、上記各実施例においては、本発明を単心の同軸ケ
ーブルに適用した場合について説明したが、多心構成の
同軸ケーブルにも本発明を適用し得るのはもちろんであ
る。
In each of the above embodiments, the present invention is applied to a single-core coaxial cable, but it goes without saying that the present invention can also be applied to a multi-core coaxial cable.

「発明の効果」 以上の説明で明らかなように、本発明によれば、中心導
体とシールドとの間に存在する絶縁体を構成rる発泡性
合成樹脂の発泡度をさほど高めることなく、中心導体と
シールドとの間の空間率を高めることができ、したがっ
て、大型コンピュータのような高い伝播速度が要求され
る用途に好適な同軸ケーブルを、比較的発泡度が小さく
品質の安定した発泡性合成樹脂を用いて容易に製造する
ことができるという効果を奏する。
"Effects of the Invention" As is clear from the above explanation, according to the present invention, the central conductor and the shield can be A coaxial cable that can increase the void ratio between the conductor and the shield and is therefore suitable for applications that require high propagation speeds, such as large computers, is made of a foamed composite with a relatively low degree of foam and stable quality. This has the advantage that it can be easily manufactured using resin.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図および第2図は本発明の一実施例を示すもので、
第1図は横断面図、第2図は中心導体に縦添えされたス
ペーサの斜視図、第3図および第4図は本発明の他の実
施例を示すものて、第3図は横断面図、第4図は中心導
体に巻回されたスペーサの斜視図である。 ■・・・・・・中心導体、2・・・・・・絶縁体層、3
・・・・・・スペーサ、4・・・・・・空間部、5・・
・・・シールド、6・・・・・・シース。
1 and 2 show an embodiment of the present invention,
FIG. 1 is a cross-sectional view, FIG. 2 is a perspective view of a spacer vertically attached to a center conductor, FIGS. 3 and 4 show other embodiments of the present invention, and FIG. 3 is a cross-sectional view. 4 are perspective views of the spacer wound around the center conductor. ■・・・Center conductor, 2・・・Insulator layer, 3
...Spacer, 4...Space part, 5...
...Shield, 6...Sheath.

Claims (1)

【特許請求の範囲】[Claims] 中心導体とこれを囲むシールドとの間に発泡性樹脂から
なる絶縁層を設けてなる同軸ケーブルにおいて、前記絶
縁層(2)の内径を中心導体(1)より大とするととも
に、中心導体と絶縁層との間の間隙の一部に、これらの
間の間隔を維持するための絶縁材料製のスペーサ(3)
を設けたことを特徴とする同軸ケーブル。
In a coaxial cable in which an insulating layer made of foamed resin is provided between a center conductor and a shield surrounding it, the inner diameter of the insulating layer (2) is larger than that of the center conductor (1), and the inner diameter of the insulating layer (2) is larger than that of the center conductor (1), Spacers (3) made of insulating material in some of the gaps between the layers to maintain the spacing between them
A coaxial cable characterized by being provided with.
JP12335988A 1988-05-20 1988-05-20 Coaxial cable Pending JPH01294308A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP12335988A JPH01294308A (en) 1988-05-20 1988-05-20 Coaxial cable

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12335988A JPH01294308A (en) 1988-05-20 1988-05-20 Coaxial cable

Publications (1)

Publication Number Publication Date
JPH01294308A true JPH01294308A (en) 1989-11-28

Family

ID=14858630

Family Applications (1)

Application Number Title Priority Date Filing Date
JP12335988A Pending JPH01294308A (en) 1988-05-20 1988-05-20 Coaxial cable

Country Status (1)

Country Link
JP (1) JPH01294308A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5781092A (en) * 1995-06-09 1998-07-14 Aisan Kogyo Kabushiki Kaisha Ignition coil for an internal combustion engine
JP2006500756A (en) * 2002-09-24 2006-01-05 クローン・インコーポレーテッド Communication wire

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5781092A (en) * 1995-06-09 1998-07-14 Aisan Kogyo Kabushiki Kaisha Ignition coil for an internal combustion engine
JP2006500756A (en) * 2002-09-24 2006-01-05 クローン・インコーポレーテッド Communication wire

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