JP2005043421A - Optical fiber cable and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase quantity of filled inclusions without increasing transmission loss and moreover to remarkably raise detaining force of secondary coated optical fibers. <P>SOLUTION: An optical fiber cable 1 consists of a long optical element part 13 obtained by, coating with: a cable sheath 11; secondary coated optical fibers 3 each of which consists of a single or a plurality of primary coated optical fibers or optical fiber ribbons; a first inclusion 5 which is arranged by being wound around surroundings of these secondary coated optical fibers 3; a second inclusion 7 which is arranged longitudinally along the surroundings of the first inclusion 5; and tension members 9 for the optical elements which are arranged at both sides of the secondary coated optical fibers 3 in the extension direction of the secondary coated optical fibers 3. Moreover, the optical fiber cable 1 has at least one notched part 15 on each surface of the cable sheath 11 on both sides of the secondary coated optical fibers 3 in a second direction perpendicular to a first direction connecting tension members 9 for the optical elements. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

なお、表１中の伝送損失は、波長１．５５μｍで「パルス試験法（ＯＴＤＲ法）・・・ＪＩＳＣ ６８２３の９」にて測定した。このパルス試験法は、図１４に示されているように各光ファイバケーブル１、４９、５３の両端の光ファイバ心線３を口出しし、ケーブルシース１１又は１０７の被覆長を１０ｍとして、片端の光ファイバ心線３を張力計５３で引っ張る。このとき、反対側の端末で、口出しした光ファイバ心線３を観察し、この光ファイバ心線３が動き始めた時の張力、つまり心線引抜力を測定する方法である。
【００５９】
表１から分かるように、比較例２の光ファイバケーブル５３では、介在充填率を約３０％とすると損失増加が発生するが、この実施の形態の光ファイバケーブル１では、伝送損失が０．２５ｄＢ／ｋｍ以下となり、良好な特性を示し、心線引抜力も約２倍に向上することが確認された。また、比較例１の光ファイバケーブル４９では、介在充填率が約３３％のとき伝送損失が０．２５ｄＢ／ｋｍ以下であるが、心線引抜力は約３０Ｎであり、この比較例１の光ファイバケーブル４９の心線引抜力に対してこの実施の形態の光ファイバケーブル１では３倍以上を示している。
【００６０】
また、この実施の形態の光ファイバケーブル１では、架空配線時に温度変化や風圧の影響により光ファイバケーブル１が伸縮した場合を想定して、光ファイバケーブル１に０．３％の伸びを与えた時の光ファイバ心線３の引き込み量を測定したところ、１０ｍｍ／端末以下と微少であり、架空配線時の光ファイバ心線３の移動抑止に効果があることを確認した。
【００６１】
この実施の形態によれば、以下の利点がある。
【００６２】
ノッチ部からケーブルシースを裂いて光ファイバ心線の口出しを行う際に、ケーブルシースは耐熱性のプラスチックヤーンまたは有機系繊維もしくは無機系繊維からなる第１，第２介在体に阻まれて光ファイバ心線内部まで食い込まないため容易に口出しを行うことができる。また、細径に製造できると共に第１，第２介在体の例えば繊維が光ファイバ心線のクッションとなるので損失特性を安定させることができる。
【００６３】
光ファイバ心線３の周囲に繊維状の第１介在体５を巻付けることにより、光ファイバ心線３が押出成形時のパイプ４３の中心近傍に、換言すれば中空部１７の中心近傍に安定的に位置することで伝送損失の劣化を防止することができる。さらに、光ファイバ心線３の周囲に巻付けた第１介在体５の外側に繊維状の第２介在体７を縦添えすることにより、この縦添えした第２介在体７がケーブルシース１１の内面と光ファイバ心線３の周囲に巻付けた第１介在体５との間でアンカーの役割を果たし、光ファイバ心線３の引抜力が大幅に向上する。したがって、伝送特性を損なうことなく心線引抜力を大幅に向上せしめることにより、架空配線時の心線移勤を抑止することが可能となる。光ファイバドロップケーブルとして利用できる。
【００６４】
第１，第２介在体の充填率を０．２〜０．５とすることにより、マクロベンディングによる曲げ損失及び伝送損失増加の発生を抑えることができる。
【００６５】
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に幅広く適用できる。
【００６６】
第１，第２介在体は溶融したケーブルシースと接触した時に溶融されることがない。
【００６７】
この製造方法により得られた光ファイバケーブルは、請求項１記載の効果と同様に、光ファイバ心線の周囲に第１介在体を巻付けることにより、光ファイバ心線が光ファイバ収納部の中心近傍に安定的に位置するので伝送損失の劣化を防止することができる。さらに、第１介在体の外側に第２介在体を縦添えすることにより、この第２介在体がケーブルシースの内面と第１介在体との間でアンカーの役割を果たすために心線引抜力を大幅に向上できる。その結果、架空配線時の心線移勤を抑止できる。光ファイバケーブルを一連の連続工程で迅速に製造できる。
【００６８】
なお，この発明は前述した実施の形態に限定されることなく、適宜な変更を行うことによりその他の態様で実施し得るものである。
【００６９】
【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、細径でかつ損失特性、施工性に優れた光ファイバを提供することができる。しかも、ノッチ部からケーブルを裂いて光ファイバ心線の口出しを容易に行うことができる。
【００７０】
また、光ファイバ心線の周囲に第１介在体を巻付けることにより、光ファイバ心線が光ファイバ収納部の中心近傍に安定的に位置するので伝送損失の劣化を防止することができる。さらに、第１介在体の外側に第２介在体を縦添えすることにより、この第２介在体がケーブルシースの内面と第１介在体との間でアンカーの役割を果たすために心線引抜力を大幅に向上できる。その結果、架空配線時の心線移勤を抑止できる。
【図面の簡単な説明】
【図１】この発明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】この発明の別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】図２の光ファイバケーブルの斜視図である。
【図４】押出ヘッド部の断面図である。
【図５】ニップル部の斜視図である。
【図６】ダイス部の斜視図である。
【図７】比較例１の光ファイバケーブルの断面図である。
【図８】図７の光ファイバケーブルの斜視図である。
【図９】比較例１の光ファイバケーブルの断面図である。
【図１０】図９の光ファイバケーブルの斜視図である。
【図１１】光ファイバケーブルを架空したときの状態説明図である。
【図１２】マクロベンディングが発生した時の図１１のＡ部の拡大断面図である。
【図１３】正常な状態の図１１のＡ部の拡大断面図である。
【図１４】パルス試験法の概略説明図である。
【図１５】従来の光ファイバケーブルの断面図である。
【図１６】従来の他の光ファイバケーブルの断面図である。
【図１７】従来の別の光ファイバケーブルの断面図である。
【図１８】従来の別の光ファイバケーブルの断面図である。
【符号の説明】
１ 光ファイバケーブル
３ ファイバ心線
５ 第１介在体
７ 第２介在体
９ 光エレメント用抗張力体
１１ ケーブルシース
１３ 光エレメント部
１５ ノッチ部
１７ 中空部
２１ 支持線
２３ シース
２５ ケーブル支持線部
２７ 首部
２９ 押出ヘッド
３５ ダイス部
４９、５３ 光ファイバケーブル[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 dropping optical fiber cable including a single optical fiber, a loose tube cable, a slot cable, and the like are conceivable. However, since the outer diameter is large and the cost is high, FIG. A cable that follows the simple drop-indoor cable 101 with a small diameter as shown in FIG. That is, in FIG. 15, a drop indoor cable 101 is a single optical fiber core wire 103 and an optical element strength member 105 disposed on both sides in parallel to the vicinity of the optical fiber core wire 103 and covered 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. 15) 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]
Referring to FIG. 16, the optical fiber drop cable 111 is a long cable in which the cable sheath 107 of the drop indoor cable 101 is covered with the support wire 113 with the same sheath material 115 as the cable sheath 107. The support wire portions 117 are integrated in parallel with each other via a neck portion 119 (see, for example, 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]
However, as shown in FIG. 17, when a multi-core strand 121 is to be accommodated in the drop indoor cable 101 instead of the single-core optical fiber 103, a plurality of strands 121 are bundled together. When the sheath is full and full, the sheath material 107 bites into the inside, and the mouth-out property is hindered.
[0009]
On the other hand, as shown in FIG. 18, when a multi-core strand 121 is put into a pipe connected to a through-hole of a nipple in an extrusion head and pushed out from the pipe, it becomes a scar, so that an optical fiber core wire is applied after construction. May move within the cable (the optical fiber core may bend and increase loss in the closure).
[0010]
The present invention has been made to solve the above-described problems.
[0011]
[Means for Solving the Problems]
An optical fiber cable of the present invention includes an optical fiber core wire,
A first inclusion wound around the optical fiber core;
A second inclusion vertically attached to surround the first inclusion;
Strength members disposed on both sides of the optical fiber core along the extending direction of the optical fiber core;
A cable sheath covering the optical fiber core wire, the first intermediate body, the second intermediate body, and the tensile body, and a second sheath orthogonal to the first direction connecting the tensile body in a plane perpendicular to the extending direction. And a cable sheath in which at least one notch is formed on each surface of the cable sheath on both sides of the optical fiber core in the direction, and has a long optical element portion.
[0012]
Therefore, an optical fiber having a small diameter and excellent loss characteristics and workability is provided. In addition, by winding the first intermediate body around the optical fiber core wire, the optical fiber core wire is stably positioned near the center of the optical fiber housing portion, so that deterioration of transmission loss is prevented. Further, by attaching the second inclusion vertically to the outside of the first inclusion, the second inclusion acts as an anchor between the inner surface of the cable sheath and the first inclusion, so that the core wire pulling force Is greatly improved. As a result, the core wire transfer during overhead wiring is suppressed.
[0013]
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.
[0014]
In the optical fiber cable according to the present invention, it is preferable that a filling rate of the first inclusion and the second inclusion in the optical fiber housing portion is 0.2 to 0.5 in the optical fiber cable. Therefore, when the filling ratio of the first and second inclusions is larger than 0.2, the degree of freedom of the optical fiber inside the optical element portion of the optical fiber cable is limited, and the optical fiber moves downward according to gravity. The tendency of macro bending to occur at the lowest position and bending loss is prevented. On the other hand, when the filling factor is smaller than 0.5, the first and second inclusions do not press the optical fiber core wire, and transmission loss is suppressed.
[0015]
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.
[0016]
In the optical fiber cable of the present invention, in the optical fiber cable, the first and second inclusions preferably include a heat-resistant plastic yarn, an organic fiber, or an inorganic fiber. Therefore, when the cable sheath is torn from the notch and the optical fiber core wire is led out, the cable sheath is blocked by the heat-resistant plastic yarn, the first and second inclusions made of organic fiber or inorganic fiber. Since the inside of the optical fiber core wire is not digged, it is easily squeezed out. In addition, the loss characteristics are stabilized because the fibers are manufactured to have a small diameter and, for example, the fibers of the first and second inclusions serve as cushions for the optical fiber core wire.
[0017]
In the optical fiber cable of the present invention, it is preferable that the melting temperature of the first and second inclusions is sufficiently higher than the melting temperature of the cable sheath in the optical fiber cable. Therefore, the first and second inclusions are not melted when they come into contact with the melted cable sheath.
[0018]
In the optical fiber cable according to the present invention, in the optical fiber cable, a straight line connecting points closest to the optical fiber core wire of the notches in a plane orthogonal to the extending direction is the optical fiber core wire and the optical fiber cable. It is preferable that it intersects with the boundary line of the shape of the hole formed in the sheath by the inclusion. Accordingly, when the cable sheath is torn from the notch and the optical fiber core wire is extracted, the extraction is easily performed.
[0019]
In the optical fiber cable of the present invention, it is preferable that the straight line is parallel to the second direction in the plane. Accordingly, when the cable sheath is torn from the notch and the optical fiber core wire is extracted, the extraction is easily performed.
[0020]
An optical fiber cable manufacturing method according to the present invention includes: an optical fiber core; a first intermediate body wound around the optical fiber core; and a second intermediate body vertically attached to surround the first intermediate body. A step of running the tensile members disposed on both sides of the optical fiber core along the extending direction of the optical fiber core, and supplying them to the extrusion head, respectively,
Extruding a thermoplastic resin into the extrusion head;
A step of forming an optical element portion in which the optical fiber core wire, the first intermediate body, the second intermediate body, and the tensile body are covered with a cable sheath, and the tensile body is connected in a plane perpendicular to the extending direction. Forming an optical element portion including a step of forming a notch portion on the surface of the cable sheath on both sides of the optical fiber core wire in the second direction orthogonal to the first direction.
[0021]
Therefore, the optical fiber cable obtained by this manufacturing method is provided with an optical fiber having a small diameter and excellent loss characteristics and workability. In addition, by winding the first intermediate body around the optical fiber core wire, the optical fiber core wire is stably positioned near the center of the optical fiber housing portion, so that deterioration of transmission loss is prevented. Further, by attaching the second inclusion vertically to the outside of the first inclusion, the second inclusion acts as an anchor between the inner surface of the cable sheath and the first inclusion, so that the core wire pulling force Is greatly improved. As a result, the core wire transfer during overhead wiring is suppressed.
[0022]
An optical fiber cable manufacturing method according to the present invention includes: an optical fiber core; a first intermediate body wound around the optical fiber core; and a second intermediate body vertically attached to surround the first intermediate body. A tension member disposed on both sides of the optical fiber core along the extending direction of the optical fiber core, and a step of feeding the support wires to the extrusion head, respectively,
Extruding a thermoplastic resin into the extrusion head;
An optical element portion in which the optical fiber core wire, the first intermediate body, the second intermediate body, 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. Forming the cable sheath on both sides of the optical fiber core in a second direction perpendicular to the first direction connecting the strength members in a plane perpendicular to the extending direction of the optical fiber core. And a molding step including a step of forming a notch portion on the surface.
[0023]
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.
[0024]
The optical fiber cable manufacturing method according to the present invention is such that, in the optical fiber cable manufacturing method, the filling rate of the first and second inclusions in the cable sheath is 0.2 to 0.5. preferable. Therefore, when the filling ratio of the first and second inclusions is larger than 0.2, the degree of freedom of the optical fiber inside the optical element portion of the optical fiber cable is limited, and the optical fiber moves downward according to gravity. The tendency of macro bending to occur at the lowest position and bending loss is prevented. On the other hand, when the filling factor is smaller than 0.5, the first and second inclusions do not press the optical fiber core wire, and transmission loss is suppressed.
[0025]
The method of manufacturing an optical fiber cable according to the present invention includes a step of supplying a first inclusion, a second inclusion, and a tensile body wound around the optical fiber core wire to the extrusion head in the method of manufacturing the optical fiber cable; The step of supplying the thermoplastic resin to the extrusion head is preferably performed simultaneously. Therefore, the optical fiber cable is rapidly manufactured in a series of continuous processes.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0027]
Referring to FIG. 1, an optical fiber cable 1 according to a first embodiment of the present invention has an optical fiber core wire 3 composed of a plurality of strands. Around the optical fiber core 3, a first inclusion 5 made of, for example, a heat-resistant plastic yarn, organic fiber, or inorganic fiber is wound so as to surround the outer periphery of the first inclusion 5. The second interposer 7 made of heat-resistant plastic yarn, organic fiber or inorganic fiber is arranged vertically. In the vicinity of both sides (left and right in FIG. 1) of the second intermediate body 7, an optical element tensile body 9 is arranged in parallel with the second intermediate body 7.
[0028]
The optical fiber core wire 3, the first intermediate body 5, the second intermediate body 7, and the optical element strength member 9 are covered with a cable sheath 11 made of a thermoplastic resin to constitute a long optical element portion 13. In a plane orthogonal to the extending direction of the fiber core wire 3, the second inclusion 7 is arranged in a direction (vertical direction in FIG. 1; second direction) orthogonal to the arrangement direction (first direction) of the optical element strength members 9. Notches 15 are formed on the surface of the cable sheath 11 located on both sides (up and down in FIG. 1).
[0029]
In the above configuration, the cable sheath 11 is blocked by the fibrous first and second inclusions 5 and 7 and does not penetrate into the optical fiber core wire 3. Therefore, when the cable sheath 11 is torn from the notch portion 15 and the optical fiber core wire 3 is extracted, the extraction can be easily performed. Moreover, since the cable 1 can be manufactured with a small diameter and the first and second inclusions 5 and 7 serve as cushions for the optical fiber core wire 3, the loss characteristics can be stabilized. As a result, the optical fiber cable 1 is simplified, the assembly process is eliminated, and the processing cost can be reduced.
[0030]
In the case of the optical fiber cable 1 shown in FIG. 1, the optical fiber core wire 3 and the first and second inclusions 5 and 7 are disposed in the hollow portion 17 of the cable sheath 11. And if the notch part 15 is provided so that the surface 19 which connects the notch part 15 which opposes may cross | intersect the hollow part 17 of the cable sheath 11 which accommodates the optical fiber core wire 3 and the 1st, 2nd inclusions 5 and 7 Good. Thus, since the tolerance | permissible_range of the position of the notch part 15 is wide, the formation position of the notch part 15 with respect to the position of the optical fiber core wire 3 does not need to be positioned correctly like the past. Therefore, the manufacture of the optical fiber cable 1 can be made easier.
[0031]
In the optical fiber cable 1 of FIG. 1, a gap is formed between the second inclusions 7 or between the second inclusions 7 and the sheath 11 in the hollow portion 17 of the cable sheath 11. Thereby, when temperature change (especially low temperature) arises in a cable, since the contraction stress of a sheath becomes difficult to be transmitted to the optical fiber core wire 3, there exists a merit which improves the stability of loss.
[0032]
Further, the filling rate of the first inclusion 5 and the second inclusion 7 in the cable sheath 11, that is, in the hollow portion 17, is set to 0.2 to 0.5. The filling rate is a value calculated by the following formula.
[0033]
(Filling rate) = (Weight of the first and second inclusions 5 and 7 used for manufacturing the unit-length optical fiber cable 1) / {(Internal area of the optical element portion 13) − (Optical fiber core wire 3) Total cross-sectional area)} × (unit length) × (density of first and second inclusions 5 and 7)
When the filling ratio of the first and second inclusions 5 and 7 is larger than 0.2, the degree of freedom of the optical fiber core wire 3 within the optical element portion 13 of the optical fiber cable 1 is limited, and gravity is reduced. Accordingly, the tendency that the bending loss occurs due to the occurrence of macro bending at the lowest position is prevented.
[0034]
On the other hand, when the filling rate is smaller than 0.5, the first and second inclusions 5 and 7 do not press the optical fiber core wire 3, and transmission loss is suppressed.
[0035]
In short, by winding the first intermediate body 5 around the optical fiber core 3, the optical fiber core 3 can be positioned at the center in the hollow portion 17, and an increase in transmission loss occurs. It is possible to increase the filling amount of the first inclusion 5. Furthermore, by vertically attaching the second inclusion 7 to the outside of the first inclusion 5 wound around the optical fiber core wire 3, the vertically attached second inclusion 7 serves as an anchor, It becomes possible to greatly improve the retaining force on the optical fiber core wire 3.
[0036]
2 and 3 show 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 13 similar to that shown in FIG. The optical fiber cable 1 further includes a long cable support line portion 25 in which the support line 21 is covered with a sheath 23. The support wire 21 is made of, for example, a steel wire. The sheath 23 is a thermoplastic resin and is formed integrally with the cable sheath 11. Therefore, the cable support line portion 25 is integrated with the optical element portion 13 in parallel via the neck portion 27. In the plane perpendicular to the extending direction of the fiber core wire 3, the support wire 21, the pair of strength members 9, and the fiber core wire 3 are arranged along the first direction.
[0037]
With this configuration, the optical fiber cable 1 has the long cable support line portion 25 in which the support wire 21 is covered with the sheath 23 and is integrated with the optical element portion 13 through the neck portion 27 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.
[0038]
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. Examples of the organic fibers or inorganic fibers as the first and second inclusions 5 and 7 include heat-resistant plastic yarns such as nylon and PET (or polypropylene), Kevlar fibers, glass wool, and cotton yarn. It is preferably used.
[0039]
The melting temperature of the first and second inclusions 5 and 7 is preferably sufficiently higher than the melting temperature of the cable sheath made of thermoplastic resin. Here, sufficiently high means that the first and second inclusions 5 and 7 do not melt when they come into contact with the molten sheath thermoplastic resin. Further, as the tensile element 9 for the optical element, a steel wire, FRP or the like is preferably used, and a steel wire is used for the support wire 21.
[0040]
In the first and second embodiments described above, a gap is formed between the second inclusions 7 or between the second inclusions 7 and the sheath 11 in the hollow portion 17 of the cable sheath 11. However, it may be in a state where the space between the second interposer 7 and the sheath 11 is fully extruded and closely adhered at the time of extrusion molding. In this case, as shown in FIG. 1, in a plane orthogonal to the extending direction of the optical fiber core 3, the straight line 14 connecting the points 15a and 15b closest to the optical fiber core 3 of each notch portion 15 is It is desirable that the optical fiber core wire 3 and the intervening body 5 intersect the boundary line of the shape of the hole 17 formed in the cable sheath 11.
[0041]
Next, a method for manufacturing the optical fiber cable 1 shown in FIG. 2 will be described.
[0042]
Referring to FIG. 4, a sectional view of the extrusion head 29 is shown, and a nipple portion 31 as shown in FIG. As shown in FIG. 6, 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 in FIG. 2 is provided on the outer periphery of 31. In this case, protrusions 37a and 37b for forming the notch portion 15 are provided in the die hole 33 at a position corresponding to the notch portion 15 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.
[0043]
Further, as shown in FIG. 4, for example, a nipple hole 41 is formed in the nipple portion 31 as a through hole through which the optical fiber core wire 3 and the first interposition body 5 pass. A pipe 43 having a substantially circular cross section that extends to the tip of the die hole 33 in the pushing direction (left direction in FIG. 4) in front of the nipple hole 41 (leftward in FIG. 5) is connected to the front of the nipple hole 41. Has been. Further, a nipple hole 45 through which the optical element tensile member 9 passes is provided on both outer sides of the nipple hole 41, and a nipple hole 47 through which the support line 21 passes is formed outside (left side) of the left nipple hole 45 in FIG. Has been.
[0044]
4 and 5, the optical fiber core wire 3 wound on a reel (not shown) provided on the right side, the first intervening body 5 such as a plurality of fibers, the second intervening body 7, and the like in FIG. The optical element strength member 9 and the support wire 21 are pulled out and sent into the extrusion head 29. When the plurality of optical fiber core wires 3, the first interposition body 5, and the second interposition body 7 pass through the nipple holes 41 and the pipes 43 of the nipple portion 31 in the extrusion head 29, the first interposition body 5 includes a plurality of A second intervening body 7 is vertically attached around the first interposing body 5 while being wound around the optical fiber core wire 3. Accordingly, each of the optical fiber core wires 3, the first interposed body 5, and the second interposed body 7 is disposed in the hollow portion 17.
[0045]
Further, the two optical element strength members 9 pass through the nipple holes 45 of the nipple portion 31, and the one support wire 21 passes through the nipple hole 47 in the left direction in FIGS. 4 and 5. At the same time, the molten thermoplastic resin P is extruded from the flow path 39 of the die portion 35, whereby the optical fiber cable 1 as shown in FIG. 2 can be obtained.
[0046]
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.
[0047]
(1) In order to allow the fiber core wire 3 and the plurality of first and second inclusions 5 and 7 to pass through the tip surface (or decapitation surface) 31a of the tip portion having a truncated cone (or decapitation cone) shape. Nipple portion 31 having a nipple hole 41 and a pair of nipple holes 45 for allowing the pair of strength members 9 to pass therethrough.
(2) A die portion 35 having a conical inner peripheral surface arranged parallel to the conical surface of the nipple portion 31 at a predetermined interval, and the fiber core wire 3 and a plurality of first and second fibers In order to form the die hole 33 for extruding the sheath thermoplastic resin P together with the intervening bodies 5 and 7 and the notch portion 15, the die portion 35 provided with projections 37 a and 37 b protruding into the die hole 33.
Here, the cross-sectional area of the nipple hole 41 is larger than the cross-sectional area of the nipple hole 45. The nipple holes 45 are arranged 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.
[0048]
In the first direction, it is desirable that the tip portions of the projecting portions 37 a and 37 b have substantially the same Cartesian coordinate value as the center of the nipple hole 41.
[0049]
And this manufacturing method has the following processes.
[0050]
(1) Pulling out the fiber core wire 3 and the first and second inclusions 5 and 7 from the nipple hole 41 (in a state where the fiber core wire 3 is surrounded by the first and second inclusions 5 and 7)
(2) Step of pulling out the tensile body 9 from the nipple hole 45
(3) Extruding the thermoplastic resin P together with the fiber core wire 3 and the plurality of first and second inclusions 5 and 7 from the die hole 33
(4) The thermoplastic resin P surrounds the fiber core wire 3, the assembly of the first and second inclusions 5 and 7, and the tensile member 9 in front of the die hole 33 in the extrusion direction. A step of solidifying the resin P and integrating the aggregate and the tensile body 9
Here, the step of drawing out the fiber core wire 3 and the first and second inclusions 5 and 7 from the nipple hole 41, the step of drawing out the tensile body 9 from the nipple hole 45, the thermoplastic resin P from the die hole 33, etc. The extruding step is simultaneously performed.
[0051]
Moreover, according to the said manufacturing method, the optical fiber cable 1 provided with the optical fiber core wire 3 and the 1st, 2nd inclusions 5 and 7, the tension body 9, the sheaths 11 and 17, and the support wire 21 is carried out in a series of continuous processes. It can be manufactured quickly.
[0052]
With the above configuration, the molten thermoplastic resin P pushed out from the flow path 39 between the nipple part 31 and the die part 35 passes through between the pipe 43 and the die hole 33 (that is, the second resin sent out from the nipple hole 33). Solidify (before contact with inclusions 7). Therefore, as shown in FIG. 1, in the hollow portion 17 of the cable sheath 11, a gap is formed between the second inclusions 7 or between the second inclusions 7 and the sheath 11 (that is, filling An optical fiber cable 1 with a rate of 0.2 to 0.5) can be obtained.
[0053]
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 21. FIG.
[0054]
Further, according to this manufacturing method, as in the manufacturing method in FIGS. 4 to 6, the optical fiber including the optical fiber core wire 3, the first intermediate body 5, the second intermediate body 7, the tensile body 9, and the sheath 11. The cable 1 can be quickly manufactured in a series of continuous processes.
[0055]
Next, the performance of the optical fiber cable 1 according to the embodiment of the present invention will be described in detail.
[0056]
The optical fiber cable 1 of this embodiment shown in FIGS. 2 and 3, the optical fiber cable 49 as the comparative example 1, and the optical fiber cable 53 as the comparative example 2 were manufactured, and their characteristics were evaluated. . The results are shown in Table 1. These have the same configuration, that is, the shape and material, except for the internal configuration of the hollow portion 17. That is, in the optical fiber cable 49 of the comparative example 1, as shown in FIG. 7 and FIG. 8, the intervening body 51 made of an aramid fiber is wound around the eight optical fiber core wires 3, Since it is the same as that of the optical fiber cable 1, a detailed description is omitted. As shown in FIGS. 9 and 10, the conventional optical fiber cable 53 as the comparative example 2 is provided with an intermediary body 55 made of an aramid fiber around the eight optical fiber core wires 3.
[0057]
In the case of this optical fiber cable 53, when it is fastened and wired by the hanging metal fitting 63 of the utility pole 61 as shown in FIG. 11, the center of the optical fiber cable 53 between the utility poles 61 is its own weight. The optical fiber core wire 3 in the optical fiber cable 53 moves in the direction of the arrow. As a result, as shown in FIG. 12, macro bending occurs in the optical fiber core wire 3, and the bending loss increases. Incidentally, in a normal state, macrobending does not occur in the optical fiber core wire 3 as shown in FIG. Further, the optical fiber core wire 3 in the optical fiber cable 53 moves, and the optical fiber core wire 3 protrudes into the connection closure or termination cabinet, or from the connection closure or termination cabinet to the cable side. If 3 is pulled in, local bending occurs in the optical fiber core wire 3, and transmission loss may increase.
[0058]
[Table 1]

The transmission loss in Table 1 was measured by “pulse test method (OTDR method)... 9 of JISC 6823” at a wavelength of 1.55 μm. In this pulse test method, as shown in FIG. 14, the optical fiber cores 3 at both ends of each of the optical fiber cables 1, 49, 53 are led out, the covering length of the cable sheath 11 or 107 is 10 m, The optical fiber core wire 3 is pulled with a tension meter 53. At this time, the optical fiber core wire 3 is observed at the opposite terminal, and the tension when the optical fiber core wire 3 starts to move, that is, the core wire pulling force is measured.
[0059]
As can be seen from Table 1, in the optical fiber cable 53 of Comparative Example 2, an increase in loss occurs when the intervening filling rate is about 30%. However, in the optical fiber cable 1 of this embodiment, the transmission loss is 0.25 dB. / Km or less, showing good characteristics, and it was confirmed that the core wire drawing force was also improved about twice. Further, in the optical fiber cable 49 of Comparative Example 1, the transmission loss is 0.25 dB / km or less when the intervening filling rate is about 33%, but the core wire pulling force is about 30 N. In the optical fiber cable 1 of the present embodiment, the fiber cable 49 has more than three times the core wire pulling force.
[0060]
Moreover, in the optical fiber cable 1 of this embodiment, 0.3% was given to the optical fiber cable 1 supposing the case where the optical fiber cable 1 expanded and contracted by the influence of temperature change and wind pressure at the time of overhead wiring. When the amount of the optical fiber core wire 3 pulled in was measured, it was as small as 10 mm / terminal or less, and it was confirmed that the optical fiber core wire 3 was prevented from moving during overhead wiring.
[0061]
According to this embodiment, there are the following advantages.
[0062]
When tearing the cable sheath from the notch to lead out the optical fiber core, the cable sheath is blocked by the first and second inclusions made of heat-resistant plastic yarn, organic fiber or inorganic fiber, and the optical fiber. Since it does not bite into the inside of the core wire, it can be easily extracted. In addition, the loss characteristics can be stabilized because the fibers can be manufactured with a small diameter and, for example, fibers of the first and second inclusions serve as cushions for the optical fiber core wire.
[0063]
By winding the first fibrous intervening body 5 around the optical fiber core 3, the optical fiber core 3 is stabilized in the vicinity of the center of the pipe 43 during extrusion molding, in other words, in the vicinity of the center of the hollow portion 17. Therefore, the transmission loss can be prevented from being deteriorated. Further, by adding a fiber-like second intermediate body 7 to the outside of the first intermediate body 5 wound around the optical fiber core wire 3, the vertical second intermediate body 7 is attached to the cable sheath 11. It plays the role of an anchor between the inner surface and the first interposer 5 wound around the optical fiber core wire 3, and the pulling force of the optical fiber core wire 3 is greatly improved. Therefore, it is possible to suppress the core wire transfer during overhead wiring by greatly improving the core wire pulling force without impairing the transmission characteristics. It can be used as an optical fiber drop cable.
[0064]
By setting the filling rates of the first and second inclusions to 0.2 to 0.5, it is possible to suppress the occurrence of bending loss and transmission loss due to macro bending.
[0065]
The present invention can be widely applied to optical fiber cores of single or plural strands or tape cores.
[0066]
The first and second inclusions are not melted when they come into contact with the melted cable sheath.
[0067]
In the optical fiber cable obtained by this manufacturing method, similarly to the effect described in claim 1, the optical fiber core is wound around the center of the optical fiber housing by winding the first inclusion around the optical fiber core. Since it is stably located in the vicinity, it is possible to prevent deterioration of transmission loss. Further, by attaching a second inclusion vertically to the outside of the first inclusion, the second inclusion acts as an anchor between the inner surface of the cable sheath and the first inclusion, so that the core wire pulling force Can be greatly improved. As a result, it is possible to suppress the core wire transfer during overhead wiring. An optical fiber cable can be quickly manufactured in a series of continuous processes.
[0068]
The present invention is not limited to the above-described embodiment, and can be implemented in other modes by making appropriate modifications.
[0069]
【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 optical fiber having a small diameter and excellent loss characteristics and workability can be provided. In addition, the optical fiber core wire can be easily led out by tearing the cable from the notch portion.
[0070]
Further, by winding the first inclusion around the optical fiber core wire, the optical fiber core wire is stably positioned near the center of the optical fiber housing portion, so that it is possible to prevent the transmission loss from deteriorating. Further, by attaching a second inclusion vertically to the outside of the first inclusion, the second inclusion acts as an anchor between the inner surface of the cable sheath and the first inclusion, so that the core wire pulling force Can be greatly improved. As a result, it is possible to suppress the core wire transfer during overhead wiring.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an optical fiber cable according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of an optical fiber cable according to another embodiment of the present invention.
FIG. 3 is a perspective view of the optical fiber cable of FIG. 2;
FIG. 4 is a cross-sectional view of an extrusion head portion.
FIG. 5 is a perspective view of a nipple portion.
FIG. 6 is a perspective view of a die part.
7 is a cross-sectional view of an optical fiber cable of Comparative Example 1. FIG.
8 is a perspective view of the optical fiber cable of FIG. 7. FIG.
9 is a cross-sectional view of an optical fiber cable of Comparative Example 1. FIG.
10 is a perspective view of the optical fiber cable of FIG. 9. FIG.
FIG. 11 is an explanatory diagram of a state when an optical fiber cable is suspended.
12 is an enlarged cross-sectional view of a part A in FIG. 11 when macro bending occurs.
13 is an enlarged cross-sectional view of a part A in FIG. 11 in a normal state.
FIG. 14 is a schematic explanatory diagram of a pulse test method.
FIG. 15 is a cross-sectional view of a conventional optical fiber cable.
FIG. 16 is a cross-sectional view of another conventional optical fiber cable.
FIG. 17 is a cross-sectional view of another conventional optical fiber cable.
FIG. 18 is a cross-sectional view of another conventional optical fiber cable.
[Explanation of symbols]
1 Optical fiber cable
3 Fiber core
5 first inclusion
7 Second inclusion
9 Tensile body for optical element
11 Cable sheath
13 Optical element section
15 Notch
17 Hollow part
21 Support line
23 sheath
25 Cable support line
27 Neck
29 Extrusion head
35 Dice part
49, 53 Optical fiber cable

Claims (12)

An optical fiber core,
A first inclusion wound around the optical fiber core;
A second inclusion vertically attached to surround the first inclusion;
Strength members disposed on both sides of the optical fiber core along the extending direction of the optical fiber core;
A cable sheath covering the optical fiber core wire, the first intermediate body, the second intermediate body, and the tensile body, and a second sheath orthogonal to the first direction connecting the tensile body in a plane perpendicular to the extending direction. An optical fiber cable having a long optical element portion comprising: a cable sheath having at least one notch portion formed on each surface of the cable sheath on both sides of the optical fiber core wire in the direction. 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 or 2, wherein a filling rate of the first inclusion and the second inclusion in the cable sheath is 0.2 to 0.5. The optical fiber cable according to any one of claims 1 to 3, 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 4, wherein the first and second inclusions include heat-resistant plastic yarns, organic fibers, or inorganic fibers. The optical fiber cable according to any one of claims 1 to 5, wherein a melting temperature of the first and second inclusions is sufficiently higher than a melting temperature of the cable sheath. A hole formed in the sheath by the optical fiber core wire and the first and second inclusions in a straight line connecting the points closest to the optical fiber core wire of each notch portion in a plane orthogonal to the extending direction. The optical fiber cable according to claim 1, which intersects a boundary line having a shape of The optical fiber cable according to claim 7, wherein the straight line is parallel to the second direction in the plane. An optical fiber core, a first interposer wound around the optical fiber core, a second interposer vertically attached to surround the first interposer, and the extending direction of the optical fiber core Each of the tensile strength members disposed on both sides of the optical fiber core wire, and supplying the extrusion head to the extrusion head,
Extruding a thermoplastic resin into the extrusion head;
A step of forming an optical element portion in which the optical fiber core wire, the first intermediate body, the second intermediate body, and the tensile body are covered with a cable sheath, and the tensile body is connected in a plane perpendicular to the extending direction. Forming an optical element portion including a step of forming a notch portion on the surface of the cable sheath on both sides of the optical fiber core wire in the second direction orthogonal to the first direction. An optical fiber core, a first interposer wound around the optical fiber core, a second interposer vertically attached to surround the first interposer, and the extending direction of the optical fiber core A tension member disposed on both sides of the optical fiber core, and a step of running the support wires respectively and supplying them to the extrusion head;
Extruding a thermoplastic resin into the extrusion head;
An optical element portion in which the optical fiber core wire, the first intermediate body, the second intermediate body, 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. Forming the cable sheath on both sides of the optical fiber core in a second direction perpendicular to the first direction connecting the strength members in a plane perpendicular to the extending direction of the optical fiber core. And a forming step including a step of forming a notch portion on the surface. The method for manufacturing an optical fiber cable according to claim 9 or 10, wherein a filling rate of the first and second inclusions in the cable sheath is 0.2 to 0.5. 12. The step of supplying the first inclusion, the second inclusion, and the tension member wound around the optical fiber core wire to the extrusion head and the step of supplying the thermoplastic resin to the extrusion head are performed simultaneously. The manufacturing method of the optical fiber cable in any one of.

Images