JP2005049505A - Optical fiber cable and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve tensile strength or breaking strength of a tension body itself as well as adhesion between the cable sheath of an optical element and the tension body by increasing the cross section of the tension body without impairing flexibility in the second direction of an optical fiber cable. <P>SOLUTION: The optical fiber cable 1 is composed of a coated optical fiber 3 and tension bodies 5 that are arranged on both sides of the coated optical fiber 3 along its extending direction and that are made of a non-conductive material having a cross section, in which the first width a' in the first direction connecting the tension bodies 5 in a plane vertical to the extending direction is larger than the second width b' in the second direction orthogonal to the first direction. In addition, the optical fiber cable 1 is equipped with a long optical element 9 having a cable sheath 7 that covers the coated optical fiber 3 and the tension bodies 5 and that has at least one notch 11 formed on the surface of the cable sheath 7 on both sides of the coated optical fiber 3 in the second direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

なお、表１における最小曲げ半径としては、光ファイバケーブル１からケーブル支持線部１９を切り離して光エレメント部９のみとし、この光エレメント部９を第２方向に曲げを加えていった際に、光エレメント用抗張力体５が挫屈する半径を測定した。そして、従来の抗張力体１０５（非導電性材料の）を使用した光ファイバケーブル１１１と比較して最小曲げ半径が大きかった場合を×、同等以上の場合を○とした。
【００６１】
また、表１における破断荷重としては、光ファイバケーブル１からケーブル支持線部１９を切り離して光エレメント部９のみとし、この光エレメント部９に引張り荷重を印加した際に、光エレメント用抗張力体５が破断する荷重を測定した。そして、従来形状の抗張力体１０５を使用した光ファイバケーブル１１１と比較して破断荷重が等倍より大きく且つ１．５倍以下を○とし、１．５倍より大きいとものを◎とした。
【００６２】
また、表１における密着力としては、１０ｍｍのケーブルシース７を残して、常温で光エレメント用抗張力体５に引張力を加えてケーブルシース７から引き抜く際に要した力が従来形状の抗張力体１０５を使用した光ファイバケーブル１１１と比較して１．０倍より大きく且つ１．５倍以下を○とし、１．５倍より大きいとものを◎とした。
【００６３】
なお、表１に示した第１幅寸法ａ’と第２幅寸法ｂ’の比（ａ’／ｂ’）は、例として挙げたもので、第１幅寸法ａ’が光ファイバ心線３と光エレメント部９の第１方向側の端縁との間の距離を超えなければ、第１幅寸法ａ’を自由に変化させることが可能である。
【００６４】
表１の結果により、この実施の形態の光ファイバケーブル１は、従来の光ファイバケーブル１１１と比較して、可撓性は同等であるので可撓性を損なうことなく、引張特性を向上させていることが明らかである。
【００６５】
次に、上記のように試作したこの実施の形態の光ファイバケーブル１の種々の特性評価結果について表２に示した。
【００６６】
【表２】

表２の結果から分かるように、第１幅寸法ａ’と第２幅寸法ｂ’の比（ａ’／ｂ’）を１より大きくした形状の光エレメント用抗張力体５を用いた光ファイバケーブル１の特性は、従来の光ファイバケーブル１１１の特性と同等であるので、この実施の形態の光エレメント用抗張力体５の断面形状の第１幅寸法ａ’と第２幅寸法ｂ’の比（ａ’／ｂ’）が他の特性に悪影響を与えることがないことも確認されている。
【００６７】
この実施の形態によれば、以下の利点がある。
【００６８】
光ファイバケーブル１は、光エレメント用抗張力体５の第２幅寸法ｂ’が従来の光ファイバケーブル１１１の抗張力体１０５の第２方向の幅寸法ｂと同じ値で、且つ第１幅寸法ａ’が第２幅寸法ｂ’より大きい扁平形状としたことにより、従来の光ファイバケーブル１１１の短径方向（第２方向）の可撓性と同様の可撓性を保持しつつ、つまり前記可撓性を損なうことなく光エレメント用抗張力体５の断面積を増大できるので、光エレメント用抗張力体５自体の引張強度ないしは破断強度を向上させることが可能である。
【００６９】
上記の理由で、光ファイバケーブル１の前記可撓性を損なうことなく光エレメント部９の破断強度を目的に応じて設定することが可能である。
【００７０】
さらに、光エレメント用抗張力体５の外周面積が増大するので、光ファイバケーブル１の第２方向の可撓性を損なうことなく、ケーブルシース７と光エレメント用抗張力体５との密着力を向上させることが可能である。
【００７１】
従来では、光ファイバケーブル１１１のケーブルシース１０７と抗張力体１０５の密着力を向上させるために接着剤等を塗布する必要があったが、この実施の形態では、光エレメント用抗張力体５の第１方向の第１幅寸法ａ’を第２方向の第２幅寸法ｂ’より大きくすることにより、ケーブルシース７との接触面積が増大するので、接着剤を塗布することなくケーブルシース７との密着力を確保することが可能である。
【００７２】
上記の理由により、光エレメント用抗張力体５の第１方向の第１幅寸法ａ’を任意に調整することにより、光エレメント用抗張力体５自体の表面積を増やすことができ、換言すればケーブルシース７との接触面積を任意に増大することができるので、ケーブルシース７との密着力を自由に上げることが可能である。しかも、第２方向の第２幅寸法ｂ’は従来の場合と同じとすることにより光ファイバケーブル１の第２方向の可撓性が低下することもない。
【００７３】
また、単数または複数の素線またはテープ心線の光ファイバ心線３に幅広く適用できる。
【００７４】
この製造方法により得られた光ファイバケーブル１は、第２方向の可撓性を従来の場合と同様の可撓性を保持しつつ、つまり前記可撓性を損なうことなく光エレメント用抗張力体５の断面積を増大できるので、光エレメント用抗張力体５自体の引張強度ないしは破断強度、さらにはケーブルシース７との密着力を向上させることが可能である。
【００７５】
また、上記の理由で、光ファイバケーブル１の前記可撓性を損なうことなく光エレメント部９の引張強度ないしは破断強度、さらにはケーブルシース７との密着力を目的に応じて設定することが可能である。
【００７６】
【発明の効果】
以上のごとき発明の実施の形態の説明から理解されるように、この発明によれば、落雷時の誘導による事故が防止されると共に光ファイバケーブルの第２方向の可撓性を損なうことなく、抗張力体の断面積を増大できるので、抗張力体自体の引張強度ないしは破断強度、さらには光エレメント部のケーブルシースと抗張力体の密着力を向上できる。
【００７７】
また、上記の理由で、光ファイバケーブルの前記可撓性を損なうことなく光エレメント部の引張強度ないしは破断強度、さらにはケーブルシースとの密着力を目的に応じて設定できる。
【図面の簡単な説明】
【図１】この発明の第１の実施の形態の光ファイバケーブルの断面図である。
【図２】この発明の第２の実施の形態の光ファイバケーブルの断面図である。
【図３】この発明の第３の実施の形態の光ファイバケーブルの断面図である。
【図４】（Ａ）〜（Ｄ）は、この実施の形態の光ファイバケーブルの光エレメント用抗張力体における種々の断面形状を示す説明断面図である。
【図５】押出ヘッド部の断面図である。
【図６】ニップル部の斜視図である。
【図７】ダイス部の斜視図である。
【図８】従来の光ファイバケーブルの断面図である。
【図９】従来の他の光ファイバケーブルの断面図である。
【図１０】従来の別の光ファイバケーブルの断面図である。
【図１１】（Ａ）〜（Ｄ）は、従来の光ファイバケーブルの光エレメント用抗張力体における種々の断面形状を示す説明断面図である。
【符号の説明】
１ 光ファイバケーブル
３ 光ファイバ心線
５ 光エレメント用抗張力体
７ ケーブルシース
９ 光エレメント部
１１ ノッチ部
１５ 支持線
１７ シース
１９ ケーブル支持線部
２１ 首部
２３、２５，２７ 光エレメント用抗張力体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multi-fiber pulling optical fiber cable and a manufacturing method thereof.
[0002]
[Prior art]
About 1 or 2 cores are usually used as optical fiber cables (drop cables) for premises and aerials. However, as FTTH (Fiber to the home) expands, it is about 4 to 10 cores for small-scale condominiums and buildings. Multi-center demand is expected.
[0003]
Further, from the viewpoint of the post-branch workability, it is considered effective to use a single strand (or a tape optical fiber core having about two cores) as the optical fiber core to be housed.
[0004]
When an attempt is made to design a multi-fiber optical fiber cable with a single optical fiber core, a loose tube cable, a slot cable, etc. are conceivable. A cable that follows the simple drop-indoor cable 101 with a small diameter as shown in FIG. That is, in FIG. 8, a drop indoor cable 101 is obtained by coating a two-core optical fiber core 103 and an optical element tensile body 105 disposed in parallel on the both sides with a cable sheath 107. A notch portion 109 is formed on the surface of the cable sheath 107 on both sides (up and down in FIG. 8) of the optical fiber core wire 103 in a direction orthogonal to the direction in which the optical element strength members 105 are connected. (For example, refer to Patent Document 1).
[0005]
Further, referring to FIG. 9, the optical fiber drop cable 111 has the above drop / indoor cable 101 as an optical element portion, and the support sheath 113 is made of the same resin as that of the cable sheath 107. Long cable support wire portions 117 covered with a sheath material 115 are integrated in parallel with each other via a neck portion 119 (see, for example, Patent Document 1 and Patent Document 2).
[0006]
[Patent Document 1]
JP 2000-171673 A
[0007]
[Patent Document 2]
JP 2001-83385 A
[0008]
[Problems to be solved by the invention]
By the way, in addition to the optical fiber cable 101 and the optical fiber drop cable 111 described above, in other conventional optical fiber cables, for example, the support wire 113 of the cable support wire portion 117 and the strength member 105 of the optical element portion 101 are conductive. Because of this metal wire, accidents caused by lightning strikes, such as accidents where indoor equipment burns, are at risk. Therefore, the optical fiber drop cable 111 is cut in a connection box installed on an outdoor wall surface of a building or a general home so that the optical element unit 101 is not drawn indoors as it is, or a special tool is used. Thus, only the tensile strength member 105 (steel wire) in the optical element 109 part is cut and the optical fiber core wire 103 is drawn indoors.
[0009]
Incidentally, since the cable support line part 117 is cut and fixed when it is secured under a utility pole or a general household eaves as described above, it does not cause much problem.
[0010]
In order to improve the above problems, the tensile body 105 in the optical element unit 101 in question is made non-metallic from a metal material of a conductive material to a non-conductive material such as glass fiber, aramid fiber, or ERP. Is improved.
[0011]
In general, in the optical fiber drop cable 111, if the adhesion between the strength member 105 and the cable sheath 107 is weak, bending, ironing, etc. are applied to the optical fiber drop cable 111 as described in Patent Document 1. If a thermal history such as a heat cycle is given in addition to this, an optical transmission loss increases or an abnormality such as disconnection of the optical fiber core wire 103 housed in the cable occurs. There was a problem.
[0012]
Therefore, the adhesion force (pull-out force) between the strength member 105 and the cable sheath 107 in the optical element portion 101 is a necessary item in terms of the characteristics of the optical fiber drop cable 111.
[0013]
However, when the optical fiber drop cable 111 is manufactured by extrusion molding, a non-conductive material such as glass fiber, aramid fiber, or FRP used as the tensile body 105 in the optical element portion 101 is used as it is. Adhesive strength cannot be obtained simply by extrusion molding together with other members such as the optical fiber core 103 and the like. Therefore, in Patent Document 1, since an adhesive layer is interposed between the tensile body 105 and the cable sheath 107 in order to increase the above-described adhesion, the manufacturing process is increased and the cost is high.
[0014]
Therefore, in the non-metallic optical fiber drop cable in which the strength member 105 in the optical element unit 101 is made of a non-conductive material, the cross-sectional shape of the strength member is a square shape as shown in FIGS. 10 and 11B, for example. The surface area of the outer peripheral surface of the tensile body 121 is increased, or the star-shaped tensile body 123 as shown in FIG. 11 (C), or the cross as shown in FIG. 11 (D). It is conceivable to increase the adhesion force between the tensile body 105 and the cable sheath 107 in the optical element portion 101 without using an adhesive layer as described above, by using an uneven shape such as a mold-shaped tensile body 125 and the like, as described above. It is done.
[0015]
However, when the optical element unit 101 is directly drawn indoors, since the tensile body 105 is non-conductive, that is, a non-metallic material, the tensile characteristics are lower than that of the metal material, so that the tensile characteristics of the tensile body 105 can be improved. The cross-sectional area must be increased. Therefore, the cross-sectional shape of the strength member 105 is not limited to a round shape, a square shape, or an irregular shape as shown in FIGS. In A) to (D), when the a dimension in the horizontal direction (first direction) and the b dimension in the vertical direction (second direction) are the same, the cross-sectional area of each tensile body 105 (and 121, 123, 125). Since the dimension “a” and the dimension “b” increase in the same manner, the buckling radius of the strength member 105 against the bending of the optical element portion 101 in the minor axis direction (vertical direction in FIGS. 8 to 10; second direction). Will become bigger. That is, there is a problem that when the bending is applied, the tensile strength member 105 is easily buckled, and the optical fiber may be disconnected.
[0016]
The present invention has been made to solve the above-described problems.
[0017]
[Means for Solving the Problems]
An optical fiber cable of the present invention includes an optical fiber core wire,
A tensile body disposed on both sides of the optical fiber core along the extending direction of the optical fiber, the first width dimension in the first direction connecting the tensile bodies in a plane perpendicular to the extending direction. A tensile body made of a non-conductive material having a cross-sectional shape larger than the second width dimension in the second direction perpendicular to the first direction;
A cable sheath covering the optical fiber core and the tensile body, and at least one notch portion on each surface of the cable sheath on both sides of the optical fiber core in the second direction in a plane perpendicular to the extending direction. A cable sheath formed with,
A long optical element portion.
[0018]
Therefore, an accident caused by a lightning strike is prevented, and the flexibility of the optical fiber cable in the second direction is maintained at the same level as that of the conventional case, that is, without sacrificing the flexibility, the cross-sectional area of the tensile body. As a result, the tensile strength or breaking strength of the strength member itself and the adhesion between the cable sheath of the optical element portion and the strength member are improved.
[0019]
The optical fiber cable according to the present invention is a long cable support line portion in which the support line is covered with a sheath in the optical fiber cable, and the cable support line portion is arranged in parallel with the optical element portion and integrated. It is preferable to have.
[0020]
In the optical fiber cable according to the present invention, it is preferable that the optical fiber core has one or a plurality of strands or tape cores. Therefore, it is widely applied to the optical fiber core wire of a single strand or a some strand or a tape core wire.
[0021]
In the optical fiber cable according to the present invention, in the optical fiber cable, the first width dimension of the strength member is smaller than the distance between the optical fiber core wire and the edge of the cable sheath in the first direction. It is preferable. Therefore, in this range, the cross-sectional area of the tensile body increases without impairing the flexibility of the optical fiber cable, so the tensile strength or breaking strength of the optical element part, and the adhesion strength with the cable sheath are set according to the purpose. It becomes possible to do.
[0022]
An optical fiber cable manufacturing method according to the present invention includes an optical fiber core and tensile strength members disposed on both sides of the optical fiber core along the extending direction of the optical fiber, and perpendicular to the extending direction. A strength member made of a non-conductive material having a cross-sectional shape in which a first width dimension in a first direction connecting the strength elements in a plane is larger than a second width dimension in a second direction perpendicular to the first direction; Each running and feeding to the extrusion head;
Extruding a thermoplastic resin into the extrusion head;
Forming an optical element portion in which the optical fiber core and the tensile body are covered with a cable sheath, wherein the cable sheath is formed on both sides of the optical fiber core in the second direction in a plane perpendicular to the extending direction. Forming an optical element portion including a step of forming a notch portion on the surface;
It is what has.
[0023]
Therefore, the optical fiber cable obtained by this manufacturing method prevents accidents caused by lightning strikes and maintains the flexibility of the optical fiber cable in the second direction as in the conventional case, that is, the above-described possibility. Since the cross-sectional area of the strength member increases without impairing the flexibility, the tensile strength or breaking strength of the strength member itself and the adhesion between the cable sheath of the optical element portion and the strength member are improved.
[0024]
Further, for the reasons described above, the tensile strength or breaking strength of the optical element portion, and further the adhesion strength with the cable sheath can be set according to the purpose without impairing the flexibility of the optical fiber cable.
[0025]
An optical fiber cable manufacturing method according to the present invention includes an optical fiber core and tensile strength members disposed on both sides of the optical fiber core along the extending direction of the optical fiber, and perpendicular to the extending direction. A tensile body having a cross-sectional shape in which the first width dimension in the first direction connecting the strength bodies in the plane is larger than the second width dimension in the second direction perpendicular to the first direction is caused to travel to the extrusion head. Supplying, and
Extruding a thermoplastic resin into the extrusion head;
An optical element portion in which the optical fiber core wire and the tensile body are covered with a cable sheath, and a cable support wire portion in which the support wire is covered with a sheath are arranged in parallel and integrally formed, and the stretching Forming a notch part on the surface of the cable sheath on both sides of the optical fiber core in the second direction in a plane perpendicular to the direction,
It is what has.
[0026]
The method for manufacturing an optical fiber cable according to the present invention can provide the same operation as the above-described method for manufacturing an optical fiber cable.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0028]
Referring to FIG. 1, an optical fiber cable 1 according to a first embodiment of the present invention has two optical fiber cores 3 and the vicinity of both sides (left and right in FIG. 1) of the optical fiber core 3. For example, an optical element tensile body 5 as a tensile body is disposed at the position in parallel with the extending direction of the optical fiber core wire 3.
[0029]
In the optical element strength member 5, the first width dimension a ′ in the arrangement direction (first direction) of the optical element strength member 5 is within the first direction in the plane orthogonal to the extending direction of the optical fiber core wire 3. It is made of a non-conductive material having a flat (ellipse) cross section larger than the second width dimension b ′ in the direction perpendicular to the direction (vertical direction in FIG. 1; second direction).
[0030]
4A, the cross section of the optical element strength member 5 is an ellipse in which the first width dimension a ′ in the first direction in FIG. 1 is larger than the second width dimension b ′ in the second direction. Shape. That is, the second width dimension b ′ of the optical element strength member 5 of FIG. 1 is set to the same value as the width dimension b in the second direction of the strength member 105 of the conventional optical fiber cable, and the first width dimension a ′ is the first width dimension b ′. It has an elliptical shape larger than the two-width dimension b ′.
[0031]
The non-conductive material (non-metal material) of the optical element strength member 5 includes non-conductive materials of plastic materials in general including glass FRP, aramid FRP, polyester and the like.
[0032]
Further, the optical fiber core wire 3 and the optical element strength member 5 are covered with a cable sheath 7 made of a thermoplastic resin to constitute a long optical element portion 9.
[0033]
Further, a notch portion 11 is formed on the surface of the cable sheath 7 located on both sides (up and down in FIG. 1) of the optical fiber core wire 3 in the second direction in a plane orthogonal to the extending direction of the optical fiber core wire 3. Is formed.
[0034]
In consideration of the lead-out property of the optical fiber core wire 3, each notch portion 11 is closest to the optical fiber core wire 3 in a plane orthogonal to the extending direction of the optical fiber core wire 3 as shown in FIG. 1. It is desirable that the straight line 13 connecting the points 11a and 11b intersects the boundary line with the optical fiber core wire 3.
[0035]
In the above configuration, in the case of the optical fiber cable 1 shown in FIG. 1, the optical element strength member 5 is made of a non-conductive material, so that an accident caused by lightning strike is prevented. In addition, the optical element strength member 5 has a second width dimension b ′ that is the same value as the width dimension b in the second direction of the strength element 105 of the conventional optical fiber cable 101 and the first width dimension a ′ is the first value. Since it has an elliptical shape larger than the two-width dimension b ′, it retains the same flexibility as that of the conventional optical fiber cable 101 in the short-diameter direction (corresponding to the second direction) while maintaining the strength of the optical element. 5 increases, the tensile strength or breaking strength of the optical element strength member 5 itself is improved.
[0036]
Furthermore, since the outer peripheral surface area of the optical element tensile member 5 increases, the cable sheath 7 and the optical element tensile member 5 are not damaged without impairing the flexibility of the optical fiber cable 1 in the short diameter direction (second direction). Adhesion will be improved.
[0037]
Further, the cable sheath 7 can be torn from the notch portion 11, and the optical fiber core wire 3 can be easily led out. Moreover, the cable 1 can be manufactured in a small diameter.
[0038]
FIG. 2 shows an optical fiber cable 1 according to a second embodiment of the present invention. The optical fiber cable 1 has a long optical element portion 9 similar to that shown in FIG. The optical fiber cable 1 further includes a long cable support line portion 19 in which the support line 15 is covered with a sheath 17. The support wire 15 is made of, for example, a steel wire. The sheath 17 is a thermoplastic resin and is formed integrally with the cable sheath 7. Therefore, the cable support line portion 19 is integrated with the optical element portion 9 in parallel via the neck portion 21. In addition, in the plane orthogonal to the extending direction of the optical fiber core wire 3, the support wire 15, the pair of optical element strength members 5, and the optical fiber core wire 3 are arranged along the first direction. .
[0039]
With this configuration, the optical fiber cable 1 is formed by integrating the long cable support line portion 19 in which the support wire 15 is covered with the sheath 17 and the optical element portion 9 through the neck portion 21 in parallel with each other. It can be used as an optical fiber drop cable and has the same effect as the effect in FIG.
[0040]
The optical fiber core 3 may be a single strand or a tape strand in addition to a plurality of strands. In particular, a 0.25 mm strand is most preferably used, but a 2-core tape core or a single core of about 0.4 to 0.9 mm is also used.
[0041]
3 and 4B, the optical fiber cable 1 of the third embodiment is light corresponding to the optical element strength member 5 of the optical element portion 9 of the optical fiber cable 1 of FIG. As shown in FIG. 4B, the element strength member 23 has a rectangular shape in which the first width dimension a ′ in the first direction is larger than the second width dimension b ′ in the second direction. That is, the second width dimension b ′ of the optical element tensile body 23 is set to the same value as the width dimension b in the second direction of the optical element tensile body 121 of the conventional optical fiber cable 111, and the first width dimension a ′ is The rectangular shape is larger than the second width dimension b ′. Others are the same as those of the optical fiber cable 1 of FIG. 2 described above, and the same members are denoted by the same reference numerals and detailed description thereof is omitted. Accordingly, the optical element strength member 23 having a rectangular cross section provides the same functions and effects as the above-described elliptical strength member 5 for optical elements shown in FIG.
[0042]
Furthermore, as another embodiment of the optical element strength member, the uneven optical element strength member 25 having a star shape as shown in FIG. As shown in (D), the concavo-convex shape optical element tension member 27 having a cross shape may be used, or another irregular shape may be used. In these cases as well, as described in the above-described embodiment, the second width dimension b ′ is the light of the conventional optical fiber cable 111 as in the elliptical shape in FIG. 4A and the rectangular shape in FIG. The element tensile strength members 123 and 125 have the same value as the width dimension b in the second direction, and the first width dimension a ′ is larger than the second width dimension b ′. Effect.
[0043]
In the case of the concavo-convex shape optical element tension members 25 and 27 as shown in FIGS. 4C and 4D, the adhesion with the cable sheath 7 is further improved by the concavo-convex shape anchoring effect.
[0044]
Next, a method for manufacturing the optical fiber cable 1 shown in FIG. 2 will be described.
[0045]
Referring to FIG. 5, a cross-sectional view of the extrusion head 29 is shown, and a nipple portion 31 as shown in FIG. As shown in FIG. 7, for example, a die portion 35 having a die hole 33 having substantially the same shape as the outer peripheral shape of the cross section of the optical fiber cable 1 of FIG. 2 is provided on the outer periphery of 31. In this case, projecting portions 37a and 37b for forming the notch portion 11 are provided in the die hole 33 at a position corresponding to the notch portion 11 of the cable 1 of FIG. Between this die part 35 and the said nipple part 31, the flow path 39 through which the thermoplastic resin P as a sheath is extruded is provided.
[0046]
Further, as shown in FIG. 6, for example, a nipple hole 41 as a through hole through which the optical fiber core wire 3 passes is formed in the nipple portion 31. Further, a nipple hole 43 through which the optical element strength member 5 passes is provided on both outer sides of the nipple hole 41, and a nipple hole 45 through which the support line 15 passes is formed outside (left side) of the left nipple hole 43 in FIG. Has been.
[0047]
5 and 6, the optical fiber core wire 3, the two optical element strength members 5 and the support wire 15 wound around a reel (not shown) provided on the right side are drawn out and extruded. It is sent into the head 29. The two optical fiber core wires 3 are arranged in advance so as to pass through the nipple holes 41 of the nipple portion 31 in the extrusion head 29.
[0048]
Further, the two optical element strength members 5 pass through the nipple holes 43 of the nipple portion 31, and one support line 15 passes through the nipple hole 45 in the left direction in FIGS. 5 and 6. At the same time, the molten thermoplastic resin P is extruded from the flow path 39 of the die portion 35.
[0049]
In short, the manufacturing method of the optical fiber cable 1 has the following characteristics. That is, in this manufacturing method, the extrusion head 29 is used, and this extrusion head 29 has the following.
[0050]
(1) The tip portion has a truncated cone (or truncated cone) shape, and the tip surface (or truncated surface) 31a has a nipple hole 41 for allowing the optical fiber core wire 3 to pass through and a tensile strength for a pair of optical elements. A nipple portion 31 having a pair of nipple holes 43 for allowing the body 5 to pass therethrough.
(2) The die portion 35, which has a conical inner peripheral surface arranged parallel to the conical surface of the nipple portion 31 at a predetermined interval, and together with the optical fiber core wire 3, the sheath thermoplastic resin P A die portion 35 having projecting portions 37a and 37b projecting into the die hole 33 in order to form the die hole 33 and the notch portion 11.
Here, the cross-sectional area of the nipple hole 41 is larger than the cross-sectional area of the nipple hole 43. The nipple holes 43 are disposed on both sides of the nipple hole 41 in the first direction on the tip surface 31a. Furthermore, the protrusions 37a and 37b are provided to face each other in a second direction orthogonal to the first direction in a plane parallel to the tip surface 31a.
[0051]
In the first direction, it is desirable that the tip portions of the protrusions 37 a and 37 b have substantially the same Cartesian coordinate value as the center of the nipple hole 41.
[0052]
And this manufacturing method has the following processes.
[0053]
(1) Step of drawing out the optical fiber core wire 3 from the nipple hole 41
(2) Pulling out the optical element strength member 5 from the nipple hole 43
(3) Extruding the thermoplastic resin P together with the optical fiber core wire 3 from the die hole 33
(4) The thermoplastic resin P is solidified in a state in which the thermoplastic resin P surrounds the optical fiber core wire 3 and the optical element tensile member 5 in front of the die hole 33 in the extrusion direction. 3 and the optical element tensile body 5 are integrated.
Here, the drawing process of the optical fiber core wire 3 from the nipple hole 41, the drawing process of the optical element strength member 5 from the nipple hole 43, and the extrusion process of the thermoplastic resin P or the like from the die hole 33 are performed simultaneously. Done.
[0054]
Further, according to the above manufacturing method, the optical fiber cable 1 including the optical fiber core wire 3, the optical element strength member 5, the sheaths 7 and 17, and the support wire 15 is quickly shown in FIG. In addition, the optical fiber cable 1 can be manufactured.
[0055]
In addition, the optical fiber cable 1 as shown in FIG. 1 can be obtained using another dice | dies part, without supplying said support wire 15. FIG.
[0056]
Further, according to the above manufacturing method, the optical fiber cable 1 including the optical fiber core wire 3, the optical element strength member 5 and the sheath 7 can be quickly formed in a series of continuous processes as in the manufacturing method in FIGS. Can be manufactured.
[0057]
Next, the performance of the optical fiber cable 1 according to the embodiment of the present invention will be described in detail.
[0058]
The optical fiber cable 1 of this embodiment shown in FIG. 2 and the optical fiber cable corresponding to the conventional optical fiber cable 111 shown in FIG. 9 were manufactured, and the characteristics of these were evaluated. However, these cables have the same configuration, that is, the shape and material, except for the configuration of the optical element strength member 5. In both of this embodiment and the conventional optical fiber cables 1 and 111, the optical element strength members 5 and 105 are made of a non-conductive material. The second width dimension b ′ in the second direction of the optical fiber cable 1 of this embodiment is the same as the second width dimension b of the conventional optical fiber cable 111, and the first width in the second direction of the optical fiber cable 1 is used. The dimension a ′ has an elliptical shape larger than the second width dimension b ′.
[0059]
An optical fiber cable 1 having several strength members 5 for optical elements in which the ratio (a ′ / b ′) of the first width dimension a ′ and the second width dimension b ′ is made different is manufactured. In order to confirm the flexibility with respect to the bending in the direction and the tensile characteristics, the minimum bending radius (bending radius when the optical element tensile body 5 is buckled) and the breaking load of the optical element portion 9 are measured for each cable 1. did. The results are shown in Table 1.
[0060]
[Table 1]

In addition, as the minimum bending radius in Table 1, when the cable supporting wire portion 19 is separated from the optical fiber cable 1 to be only the optical element portion 9, and the optical element portion 9 is bent in the second direction, The radius at which the tensile element 5 for optical element buckles was measured. The case where the minimum bending radius was larger than that of the optical fiber cable 111 using the conventional strength member 105 (of a non-conductive material) was evaluated as “x”, and the case where the minimum bending radius was equal to or greater than “◯”.
[0061]
Further, as the breaking load in Table 1, the cable supporting wire portion 19 is separated from the optical fiber cable 1 to be only the optical element portion 9, and when a tensile load is applied to the optical element portion 9, the optical element tensile member 5 The load at which rupture occurs was measured. In addition, the breaking load was larger than the same size and 1.5 times or less compared with the optical fiber cable 111 using the conventional strength member 105, and the larger one was larger than 1.5.
[0062]
In addition, as the adhesion force in Table 1, the force required to pull out the cable sheath 7 by applying a tensile force to the optical element tensile body 5 at room temperature while leaving the 10 mm cable sheath 7 is used. As compared with the optical fiber cable 111 using the cable, a value larger than 1.0 times and 1.5 times or less was marked as ◯, and a value larger than 1.5 times was marked as ◎.
[0063]
The ratio (a ′ / b ′) of the first width dimension a ′ and the second width dimension b ′ shown in Table 1 is given as an example, and the first width dimension a ′ is the optical fiber core wire 3. The first width dimension a ′ can be freely changed as long as the distance between the optical element portion 9 and the edge of the optical element portion 9 on the first direction side is not exceeded.
[0064]
According to the results of Table 1, the optical fiber cable 1 of this embodiment has the same flexibility as the conventional optical fiber cable 111, so that the tensile characteristics are improved without impairing the flexibility. It is clear that
[0065]
Next, Table 2 shows various characteristic evaluation results of the optical fiber cable 1 according to this embodiment, which was experimentally manufactured as described above.
[0066]
[Table 2]

As can be seen from the results in Table 2, the optical fiber cable using the optical element strength member 5 having a ratio (a ′ / b ′) of the first width dimension a ′ and the second width dimension b ′ larger than 1. Since the characteristic of 1 is equivalent to the characteristic of the conventional optical fiber cable 111, the ratio between the first width dimension a ′ and the second width dimension b ′ of the cross-sectional shape of the optical element strength member 5 of this embodiment ( It has also been confirmed that a ′ / b ′) does not adversely affect other properties.
[0067]
According to this embodiment, there are the following advantages.
[0068]
In the optical fiber cable 1, the second width dimension b ′ of the optical element strength member 5 has the same value as the width dimension b in the second direction of the strength body 105 of the conventional optical fiber cable 111 and the first width dimension a ′. Has a flat shape larger than the second width dimension b ′, so that the flexibility similar to the flexibility in the minor axis direction (second direction) of the conventional optical fiber cable 111 is maintained, that is, the flexibility Since the cross-sectional area of the optical element strength member 5 can be increased without impairing the properties, the tensile strength or breaking strength of the optical element strength member 5 itself can be improved.
[0069]
For the above reasons, it is possible to set the breaking strength of the optical element portion 9 according to the purpose without impairing the flexibility of the optical fiber cable 1.
[0070]
Furthermore, since the outer peripheral area of the optical element strength member 5 is increased, the adhesion between the cable sheath 7 and the optical element strength member 5 is improved without impairing the flexibility of the optical fiber cable 1 in the second direction. It is possible.
[0071]
Conventionally, it has been necessary to apply an adhesive or the like in order to improve the adhesion between the cable sheath 107 of the optical fiber cable 111 and the strength member 105, but in this embodiment, the first strength member 5 for the optical element is used. Since the contact area with the cable sheath 7 is increased by making the first width dimension a ′ in the direction larger than the second width dimension b ′ in the second direction, the contact with the cable sheath 7 is not applied. It is possible to secure power.
[0072]
For the above reasons, the surface area of the optical element tensile member 5 itself can be increased by arbitrarily adjusting the first width dimension a ′ in the first direction of the optical element tensile member 5, in other words, the cable sheath. Since the contact area with the cable sheath 7 can be arbitrarily increased, the adhesion force with the cable sheath 7 can be freely increased. Moreover, the second width dimension b ′ in the second direction is the same as in the conventional case, so that the flexibility in the second direction of the optical fiber cable 1 is not lowered.
[0073]
Further, the present invention can be widely applied to one or a plurality of strands or tape optical fibers 3.
[0074]
The optical fiber cable 1 obtained by this manufacturing method maintains the same flexibility in the second direction as in the conventional case, that is, the optical element strength member 5 without impairing the flexibility. Therefore, it is possible to improve the tensile strength or breaking strength of the optical element strength member 5 itself, and the adhesion with the cable sheath 7.
[0075]
For the above reasons, it is possible to set the tensile strength or breaking strength of the optical element portion 9 and the adhesive strength with the cable sheath 7 according to the purpose without impairing the flexibility of the optical fiber cable 1. It is.
[0076]
【The invention's effect】
As can be understood from the description of the embodiments of the invention as described above, according to the present invention, an accident due to lightning strike is prevented and the flexibility of the optical fiber cable in the second direction is not impaired. Since the cross-sectional area of the strength member can be increased, the tensile strength or breaking strength of the strength member itself, and the adhesion between the cable sheath of the optical element portion and the strength member can be improved.
[0077]
Further, for the above reasons, the tensile strength or breaking strength of the optical element portion and the adhesion strength with the cable sheath can be set according to the purpose without impairing the flexibility of the optical fiber cable.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an optical fiber cable according to a first embodiment of the present invention.
FIG. 2 is a sectional view of an optical fiber cable according to a second embodiment of the present invention.
FIG. 3 is a cross-sectional view of an optical fiber cable according to a third embodiment of the present invention.
FIGS. 4A to 4D are explanatory cross-sectional views showing various cross-sectional shapes of the tensile element for an optical element of the optical fiber cable of this embodiment.
FIG. 5 is a cross-sectional view of an extrusion head portion.
FIG. 6 is a perspective view of a nipple portion.
FIG. 7 is a perspective view of a die part.
FIG. 8 is a cross-sectional view of a conventional optical fiber cable.
FIG. 9 is a cross-sectional view of another conventional optical fiber cable.
FIG. 10 is a cross-sectional view of another conventional optical fiber cable.
FIGS. 11A to 11D are explanatory cross-sectional views showing various cross-sectional shapes in a conventional tensile strength member for an optical element of an optical fiber cable. FIGS.
[Explanation of symbols]
1 Optical fiber cable
3 Optical fiber core
5 Tensile body for optical element
7 Cable sheath
9 Optical element section
11 Notch
15 Support line
17 sheath
19 Cable support line
21 neck
23, 25, 27 Tensile element for optical elements

Claims (6)

An optical fiber core,
A tensile body disposed on both sides of the optical fiber core along the extending direction of the optical fiber, the first width dimension in the first direction connecting the tensile bodies in a plane perpendicular to the extending direction. A tensile body made of a non-conductive material having a cross-sectional shape larger than the second width dimension in the second direction perpendicular to the first direction;
A cable sheath covering the optical fiber core and the tensile body, and at least one notch portion on each surface of the cable sheath on both sides of the optical fiber core in the second direction in a plane perpendicular to the extending direction. A cable sheath formed with,
An optical fiber cable having a long optical element portion. The optical fiber cable according to claim 1, comprising a long cable support line portion in which a support line is covered with a sheath, the cable support line portion being arranged in parallel to the optical element portion and integrated. The optical fiber cable according to claim 1, wherein the optical fiber core includes one or a plurality of strands or a tape core. The optical fiber cable according to any one of claims 1 to 3, wherein a first width dimension of the tensile body is smaller than a distance between an optical fiber core wire and an end of the cable sheath in the first direction. . An optical fiber core and a tensile body disposed on both sides of the optical fiber core along the extending direction of the optical fiber core, the first direction connecting the tensile bodies in a plane perpendicular to the extending direction A tension body made of a non-conductive material having a cross-sectional shape larger than a second width dimension in a second direction perpendicular to the first direction, and a first width dimension of each of which is fed to the extrusion head. ,
Extruding a thermoplastic resin into the extrusion head;
Forming an optical element portion in which the optical fiber core and the tensile body are covered with a cable sheath, wherein the cable sheath is formed on both sides of the optical fiber core in the second direction in a plane perpendicular to the extending direction. Forming an optical element portion including a step of forming a notch portion on the surface;
A method for manufacturing an optical fiber cable. An optical fiber core and a tensile body disposed on both sides of the optical fiber core along the extending direction of the optical fiber core, the first direction connecting the tensile bodies in a plane perpendicular to the extending direction A tension body made of a non-conductive material having a cross-sectional shape larger than a second width dimension in a second direction perpendicular to the first direction, and a first width dimension of each of which is fed to the extrusion head. ,
Extruding a thermoplastic resin into the extrusion head;
An optical element portion in which the optical fiber core wire and the tensile body are covered with a cable sheath, and a cable support wire portion in which the support wire is covered with a sheath are arranged in parallel and integrally formed, and the stretching Forming a notch part on the surface of the cable sheath on both sides of the optical fiber core in the second direction in a plane perpendicular to the direction,
A method for manufacturing an optical fiber cable.

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