JPH0528845A

JPH0528845A - Covered electric wire with shield

Info

Publication number: JPH0528845A
Application number: JP17832591A
Authority: JP
Inventors: Kikuo Suda; 喜久雄須田
Original assignee: SANYO KOGYO KK; Sanyo Industries Ltd
Current assignee: SANYO KOGYO KK; Sanyo Industries Ltd
Priority date: 1991-07-18
Filing date: 1991-07-18
Publication date: 1993-02-05

Abstract

PURPOSE:To lessen the dielectric constant of an inner sheath by winding spirally a tape made from a non-woven cloth or Japanese paper in such a way as overlapping partially, and thus forming the inner sheath. CONSTITUTION:Conductors 1 are covered with insulation to form a signal wire 2, which is covered with a metal shield 4 with an inner sheath 3 interposed, and thus an insulated electric wire with shield is constructed, wherein the inner sheath 3 is prepared by spirally winding (wrap wind) a tape 5 of non-woven cloth or Japanese paper, which has a small dielectric constant, in such a way as overlapping partially. According to this constitution, the dielectric constant epsilonbetween the signal wire 2 and shield 4 is made smaller than a conventional sheath consisting of PVC, and the dielectric capacity between these two members becomes small. As a result, the inter-space electrostatic capacitance becomes small, and the characteristic impedance large, and the damping constant small. Therefore, an excellent characteristic with small electrostatic capacitance can be obtained despite provision of the shield 4.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、外部から内部の信号線
へ若しくは内部の信号線から外部への静電ノイズや電磁
ノイズを遮断するため金属シールドを設けたシールド付
被覆電線に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shielded covered electric wire provided with a metal shield for blocking electrostatic noise or electromagnetic noise from the outside to the inside signal line or from the inside signal line to the outside. .

【０００２】[0002]

【従来の技術及び発明が解決しようとする課題】従来は
１対以上の信号線対を撚り合わせ、その外周にノイズ対
策の為にシールド（編組シールド，アルミテープ等）を
施していた。2. Description of the Related Art Conventionally, one or more pairs of signal lines have been twisted together, and a shield (braided shield, aluminum tape, etc.) has been provided on the outer periphery thereof as a measure against noise.

【０００３】しかし、シールドを設けると信号線と金属
シールド間に静電容量が生じ、信号線対間の静電容量が
増大してしまう問題がある。However, the provision of the shield causes a problem that an electrostatic capacitance is generated between the signal line and the metal shield, and the electrostatic capacitance between the signal line pair increases.

【０００４】静電容量が増大すると、特性インピーダン
スが減少し、特に高周波信号に対する減衰が大きくな
る。When the capacitance increases, the characteristic impedance decreases, and the attenuation of high frequency signals in particular increases.

【０００５】また、減衰定数が増大するため、送信にお
いて信号自体が著しく劣化してしまう。Further, since the attenuation constant increases, the signal itself is significantly deteriorated during transmission.

【０００６】近年、通信分野においては高速伝送化が進
み、それに伴い電線の特性インピーダンス，減衰定数は
厳しい規定が設けられているが、シールドを施したこと
によりこの規定を満足できなくなる。In recent years, in the field of communication, high-speed transmission has progressed, and along with this, strict regulations have been set for the characteristic impedance and attenuation constant of electric wires. However, the provision of a shield makes it impossible to satisfy these regulations.

【０００７】そこで、金属シールドを設けても静電容量
を小さく押さえたい。Therefore, it is desired to suppress the electrostatic capacitance even if the metal shield is provided.

【０００８】この静電容量Ｃは、εＳ／ｄで定まる値で
あり、Ｓは例えば対向する導体表面積、εは対向導体間
の絶縁物の誘電率、ｄは導体間の対間距離である。The capacitance C is a value determined by εS / d, where S is, for example, the surface area of the conductors facing each other, ε is the dielectric constant of the insulator between the opposing conductors, and d is the distance between the pair of conductors.

【０００９】従って、この静電容量の増加を押さえるた
めには、導体表面積Ｓを小さくする誘電率εを小さくする対間距離ｄを大きくすることを検討する必要がある。Therefore, in order to suppress the increase in the electrostatic capacitance, it is necessary to consider decreasing the conductor surface area S and decreasing the dielectric constant ε and increasing the inter-pair distance d.

【００１０】静電容量を低減させる為の一例として図３
に示すように、単に被覆電線の外部シース６と同様にし
て、内芯部の信号線２と金属シールド４との間に押し出
し成形によってＰＶＣによる内部シース３を設けて対間
距離ｄを大きくしたシールド付被覆電線が考案されてい
る。As an example for reducing the capacitance, FIG.
As shown in FIG. 3, just like the outer sheath 6 of the covered electric wire, the inner sheath 3 made of PVC is provided between the signal wire 2 of the inner core portion and the metal shield 4 by extrusion molding to increase the inter-pair distance d. Shielded covered wires have been devised.

【００１１】しかし、このＰＶＣ内部シース３では、誘
電率εが小さくなく、金属シールド４による静電容量の
増加を十分に押さえることができない。However, in this PVC inner sheath 3, the permittivity ε is not small and the increase in capacitance due to the metal shield 4 cannot be sufficiently suppressed.

【００１２】また、電線の外径に規格制限があるため、
大幅な変更はできない。Further, since there is a standard restriction on the outer diameter of the electric wire,
It cannot be changed significantly.

【００１３】さらに、のＳについては変更することが
できないので、誘電率εを小さくすることが技術的課題
となる。Further, since S cannot be changed, it is a technical subject to reduce the dielectric constant ε.

【００１４】しかしながら、単に例えば誘電率εの小さ
いポリエチレンなどを内部シース３に採用すると、ポリ
エチレンが硬い素材のため、電線自体硬くなってしまい
実用性に劣り、また誘電率εが小さくても逆にあまり柔
らかすぎる材質にすることもできない。However, if polyethylene or the like having a small dielectric constant ε is simply used for the inner sheath 3, the wire is hard because the polyethylene is a hard material, which is inferior in practicality. It cannot be made too soft.

【００１５】本発明は、このような問題を解決し、内部
シースの誘電率εを小さくした静電容量の小さいシール
ド付被覆電線を提供するものである。The present invention solves such a problem and provides a shielded covered electric wire having a small dielectric constant ε of the inner sheath and a small electrostatic capacitance.

【００１６】[0016]

【課題を解決するための手段】添付図面を参照して本発
明の要旨を説明する。The gist of the present invention will be described with reference to the accompanying drawings.

【００１７】導体１を絶縁被覆した信号線２の外周に内
部シース３を介して金属シールド４を設けたシールド付
被覆電線において、前記内部シース３を、不織布若しく
は和紙などで形成したテープ体５を一部重合状態に螺線
巻きして形成したことを特徴とするシールド付被覆電線
に係るものである。In a shielded covered electric wire in which a metal shield 4 is provided on the outer circumference of a signal wire 2 having an insulating coating on a conductor 1, a tape body 5 in which the inner sheath 3 is formed of non-woven fabric or Japanese paper is used. The present invention relates to a shielded covered electric wire, which is formed by spirally winding a part thereof in a polymerized state.

【００１８】[0018]

【作用】内部シース３を誘電率の小さい材質である不織
布若しくは和紙などのテープ体５を使用して、テープ体
５を一部重合状態に螺線巻き（ラップ巻き）して形成す
るから、信号線２と金属シールド４間の誘電率εが従来
のＰＶＣによる内部シース３に比べて小さく、信号線２
と金属シールド４間の静電容量が小さくなり、その結
果、対間静電容量［pF/m］は小さくなり、特性インピー
ダンス［Ω］は大きく、減衰定数［dB/Km］は小さくな
る。The inner sheath 3 is formed by using a tape body 5 such as a non-woven fabric or a Japanese paper which is a material having a small dielectric constant, and winding the tape body 5 in a partially polymerized state by spiral winding (lap winding). The dielectric constant ε between the wire 2 and the metal shield 4 is smaller than that of the conventional PVC inner sheath 3,
The capacitance between the metal shield 4 and the metal shield 4 is reduced, and as a result, the capacitance between the pair [pF / m] is reduced, the characteristic impedance [Ω] is increased, and the attenuation constant [dB / Km] is reduced.

【００１９】[0019]

【実施例】テープ状の不織布をテープ巾の１／２づつ重
合する１／２ラップ巻きにより内部シース３を形成した
図１，図２に示す本実施例の試料Ｂと、押し出し成形に
よりＰＶＣで内部シース３を形成した図３に示す従来例
の試料Ａとを、金属シールド４を設けないシールド無し
電線の試料Ｃを基準に比較実験を行った。（図中符号７
は、ドレンワイヤーである。）この各試料Ａ，Ｂ，Ｃを
表１に示す。EXAMPLE A sample B of this example shown in FIGS. 1 and 2 in which the inner sheath 3 was formed by ½ wrap winding in which a tape-shaped non-woven fabric was polymerized into ½ of the tape width and PVC by extrusion molding. A comparative experiment was carried out on the basis of the sample A of the conventional example shown in FIG. 3 in which the inner sheath 3 was formed, and the sample C of the unshielded electric wire without the metal shield 4. (7 in the figure
Is a drain wire. ) Table 1 shows each of the samples A, B and C.

【００２０】[0020]

【表１】 [Table 1]

【００２１】試料の長さＬを０.５ｍと３ｍとで各値を
測定し、比較した実験結果を以下の表２，表３，表４，
表５に示す。Each value was measured with the length L of the sample being 0.5 m and 3 m, and the experimental results for comparison were shown in Tables 2, 3, and 4 below.
It shows in Table 5.

【００２２】[0022]

【表２】 [Table 2]

【００２３】[0023]

【表３】 [Table 3]

【００２４】[0024]

【表４】 [Table 4]

【００２５】[0025]

【表５】 [Table 5]

【００２６】本実施例の試料Ｂは、従来例の試料Ａに比
し、静電容量が小さく、特性インピーダンスが大きく、
減衰定数が小さい結果を得た。The sample B of this example has a smaller capacitance and a larger characteristic impedance than the sample A of the conventional example.
The results show that the damping constant is small.

【００２７】例えば、ＩＳＤＮケーブル（ＩＮＳ６４）
の規格値によって、長さＬが７ｍ未満では対間静電容量
が３００pF以下、７〜１０ｍでは３５０pF以下にする必
要がある。For example, ISDN cable (INS64)
Depending on the standard value of, the capacitance between pairs must be 300 pF or less when the length L is less than 7 m, and 350 pF or less when the length L is 7 to 10 m.

【００２８】即ち、この最大長１０ｍにおいては、３５
pF/mにする必要がある。（信号周波数１KHz）しかしな
がら、前記表５に示す実験結果のように従来例では静電
容量が３８.７pF/mであり、金属シールド４を設けてし
まうと７ｍまでしか使用できなかった。That is, at the maximum length of 10 m, 35
Must be pF / m. (Signal frequency 1 KHz) However, as shown in the experimental results shown in Table 5, the capacitance of the conventional example is 38.7 pF / m, and if the metal shield 4 is provided, it can be used only up to 7 m.

【００２９】これに対して本実施例では、３３.０pF/m
まで静電容量が下げられたため、１０ｍの使用も可能と
なった。On the other hand, in the present embodiment, 33.0 pF / m
Since the electrostatic capacity was lowered to 10 m, it became possible to use it for 10 m.

【００３０】しかも、金属シールド４までの外径を従来
例の３.９ｍｍφから３.４ｍｍφに小さくしても良いこ
ととなり、その結果外径も小さくできることとなる。Moreover, the outer diameter up to the metal shield 4 may be reduced from 3.9 mmφ in the conventional example to 3.4 mmφ, and as a result, the outer diameter can be reduced.

【００３１】一般に外径を小さくすると前述した対間距
離ｄ（内部シース径）が小さくなるため、静電容量が増
大してしまう。Generally, when the outer diameter is reduced, the above-mentioned distance d between pairs (diameter of the inner sheath) is reduced, so that the capacitance is increased.

【００３２】本実施例では、この分を含めて誘電率εの
減少を図ることに成功しているものである。In this embodiment, the dielectric constant ε has been successfully reduced including this amount.

【００３３】また、従来の押し出し成形により内部シー
ス３を形成するものではないため、やっかいな押し出し
成形の一工程を省くことができる。Further, since the inner sheath 3 is not formed by the conventional extrusion molding, it is possible to omit one troublesome extrusion molding step.

【００３４】本実施例では、不織布を用いているが、和
紙によるテープ体５のラップ巻きによっても同様な結果
が得られた。Although a non-woven fabric is used in this example, similar results were obtained by wrapping the tape body 5 with Japanese paper.

【００３５】また、本実施例では最も作業上所定の内部
シース３の厚みを形成するに容易な1/2ラップ巻きを採
用しているが、これに限られるものではない。Further, in the present embodiment, the 1/2 lap winding, which is the easiest to form a predetermined thickness of the inner sheath 3, is adopted for the work, but the present invention is not limited to this.

【００３６】[0036]

【発明の効果】本発明は、上述のようにして内部シース
を形成したため、金属シールドを設けても静電容量の小
さい秀れた特性となるシールド付被覆電線となる。Since the inner sheath is formed as described above, the present invention provides a shielded covered electric wire having excellent characteristics with a small capacitance even if a metal shield is provided.

【００３７】特にＩＳＤＮケーブルやＬＡＮケーブルな
ど静電容量規制や外径規制のある電線において、従来例
に比して仕様範囲の拡大を図ることができ、実用性に秀
れたシールド付被覆電線を提供できることとなる。Particularly, in the case of an electric wire such as an ISDN cable or a LAN cable which has a capacitance regulation and an outer diameter regulation, it is possible to expand the specification range compared to the conventional example, and to provide a shielded covered electric wire excellent in practicality. Can be provided.

【図面の簡単な説明】[Brief description of drawings]

【図１】本実施例の断面図である。FIG. 1 is a sectional view of the present embodiment.

【図２】本実施例の一部を切り欠いた斜視図である。FIG. 2 is a perspective view in which a part of the present embodiment is cut away.

【図３】従来例の断面図である。FIG. 3 is a sectional view of a conventional example.

【符号の説明】[Explanation of symbols]

１導体２信号線３内部シース４金属シールド５テープ体 1 conductor 2 signal line 3 inner sheath 4 metal shield 5 tape body

Claims

【特許請求の範囲】【請求項１】導体を絶縁被覆した信号線の外周に内部
シースを介して金属シールドを設けたシールド付被覆電
線において、前記内部シースを、不織布若しくは和紙な
どで形成したテープ体を一部重合状態に螺線巻きして形
成したことを特徴とするシールド付被覆電線。Claim: What is claimed is: 1. A shielded covered electric wire in which a metal shield is provided on the outer periphery of a signal wire whose conductor is insulated and coated with an inner sheath, and the inner sheath is formed of non-woven fabric or Japanese paper. A covered electric wire with a shield, which is formed by spirally winding a body in a partially polymerized state.