JP4674886B2

JP4674886B2 - Support for optical fiber manufacturing

Info

Publication number: JP4674886B2
Application number: JP2001185969A
Authority: JP
Inventors: 善久草野; 敦之嶋田; 利治平岡
Original assignee: Toyo Tanso Co Ltd; Shin Etsu Quartz Products Co Ltd
Current assignee: Toyo Tanso Co Ltd; Shin Etsu Quartz Products Co Ltd
Priority date: 2000-07-31
Filing date: 2001-06-20
Publication date: 2011-04-20
Anticipated expiration: 2021-06-20
Also published as: JP2002114535A

Description

【０００１】
【産業上の利用分野】
本発明は、光ファイバ製造用支持体、さらに詳しくはＯＶＤ法やＶＡＤ法等で作成した大型の光ファイバ母材から光ファイバを安定に、精度よく、しかも生産性よく製造するための光ファイバ製造用支持体に関する。
【０００２】
【従来の技術】
従来、光ファイバは、外周面が平滑な円柱状又は円筒状の耐熱性基体を回転させ、その表面に石英ガラス微粒子を吹き付け付着させ、多孔質石英ガラス母材を形成したのち、耐熱性基体又は型体上の多孔質石英ガラス母材を加熱し透明ガラス化する外付け法（ＯｕｔｓｉｄｅＶａｐｏｒＤｅｐｏｓｉｔｉｏｎＭｅｔｈｏｄ、以下「外付け法」という）や、石英ガラス微粒子を種棒の軸方向に堆積して多孔質石英ガラス母材を形成し、加熱し透明ガラス化する気相軸付け法（Ｖａｐｏｒ‐ＰｈａｓｅＡｘｉａｌＤｅｐｏｓｉｔｉｏｎＭｅｔｈｏｄ、以下「軸付け法」という）等で作成した光ファイバ用母材を外径が数分の一程度まで加熱延伸してロッドとしたのち、線引き機で、例えば外径１２５μｍのシングルモード光ファイバ等に線引きして製造されてきた。近年、シングルモード用光ファイバの実用化が進み大量の光ファイバが利用され、さらに光ファイバが一般加入者系にその利用範囲が拡大するようになれば、今後の使用量は一段と拡大することが予測されている。かかる光ファイバの使用量の拡大には、量産化、低コスト化が不可欠であり、そのための有効な手段の一つとして、実用化されている軸付け法等で大型・長尺の多孔質石英ガラス母材を作成し、それを脱水・透明ガラス化して大型で長尺な光ファイバ用母材を作製し、それを加熱延伸・線引きするのが有効であると考えられる。
【０００３】
【発明が解決しようとする課題】
しかし、光ファイバ用母材、それを加熱延伸して得られるロッドを大型化・長尺化するに伴ないその重量が増す上に、光ファイバ用母材やロッドを支持する部材（ダミー棒やダミーシャフト等と呼ばれることもあるが、本件においては「支持体」という）も長尺化する必要がありその重量が一段と増大する。その上、光ファイバ用母材やロッドを大型化・長尺化すると加熱延伸や線引き時の温度も高温となる。これまで加熱延伸や線引き工程で使用される光ファイバ用母材やロッドの支持体として、石英ガラス製支持体が用いられてきた。たしかに石英ガラスは高純度であり、かつ加工性がよいため高い寸法精度のものを得ることが可能で、また比較的高温にも耐えられる素材であるが、より一層の光ファイバ用母材やロッドの大型化・長尺化を進めようとすると、必然的に支持体にかかる重量がさらに大きくなり、また温度も一層高温となり、石英ガラス製支持体では耐荷重強度が不足する。さらに、その取扱いにおいてもガラスゆえの割れやヒビ等の破損を避けるための細心の注意が求められることとなり、従来のような小型の部材と比べてハンドリング等における作業の負担や損傷のリスクは格段に増大することになる。そこで、石英ガラス製支持体の端部に使い捨ての石英ガラス製部材を継ぎ足して、高温による変形等の生じた部分を切断して捨てる、といった方法が用いられることもあった。しかし、この使い捨てる石英ガラス製部材もまたガラス製であることから十分な耐荷重性が得られず、また石英ガラスを使い捨てることから結果的にコストの低減が十分に行えないという問題もあった。そうした耐荷重性や耐熱性等の問題を解決する支持体としてアルミナ、ジルコニア、ムライト、窒化珪素、炭化珪素等のセラミックスのほか、黒鉛化した炭素材（グラファイトカーボン）などで作製した支持体も提案されたが、耐熱性に優れた高純度なセラミックスは非常に高価であり、その上に加工性に難があるため、高精度のセラミックス製支持体を得ようとすると大幅に研削等を行なう必要がありその製造コストを高くしてしまう。
【０００４】
また、比較的安価であり、且つ耐熱性と加工性に優れ、またハンドリング等についても容易なグラファイト等の炭素材も、従来の炭素材では強度が不足し大型で長尺な光ファイバ用母材やロッドの加熱延伸・線引きする時の荷重に耐え得るものを実現することが困難であった。
【０００５】
近年、加工性とともに耐荷重性にも耐熱性にも優れ、ハンドリング等についても容易な素材でありながら、価格的にも優位で、なお且つ高純度品も可能な素材として、炭素繊維強化炭素複合材料（ＣａｒｂｏｎＦｉｂｅｒＲｅｉｎ‐ｆｏｒｃｅｄＣａｒｂｏｎＣｏｍｐｏｓｉｔｅ、以下「Ｃ／Ｃコンポジット」という）が提案され、実用化が進んできている。しかしながら、Ｃ／Ｃコンポジットは、その合成や成型等の作製上の問題、あるいは加工精度上の問題などから、１０００ｍｍを超える長さのものや１００ｍｍを超える外径のものを実用的に製造することは非常に困難であり、加熱延伸や線引き時の支持体として用いるためには、複数のロッド部材を直列に接合することによって長尺化する必要がある。この接合による長尺化としては、ロッドの端部付近に孔を穿ち接合用のピンにより係止するなど、各種の様々な治具を用いる方法が考えられるが、光ファイバ用母材やロッドの大型化が進み荷重が増大するにつれ、接合用ピンによる係止では、過大な荷重に耐えることができずピンが破損してしまうおそれが生ずる。接合用ピンに破損等が生じてしまった場合、接合が不完全なものとなるため支持体の寸法精度が損なわれ、所望の形状の光ファイバ用ロッドを得ることができなくなる。さらに、図４にも示されるように、ピンによる係止の場合、取扱上ピンの挿入孔の径をピン自体の径よりも大きくせざるを得ないため、どうしてもピンとその挿入孔との間には隙間が存在してしまい、それが「がた」を発生させ支持体自体が曲がり光ファイバの偏心の原因ともなっていた。
【０００６】
【課題を解決するための手段】
こうした現状に鑑み、本発明者等は、鋭意研究を続けた結果、前記Ｃ／Ｃコンポジットが高純度に作製できる上に耐熱性、加工性に優れ、かつ比較的安価であることから、このＣ／Ｃコンポジットで光ファイバ製造用支持体を作製するのが最善であると考え、従来のＣ／Ｃコンポジットからなる光ファイバ製造用支持体の改善に努めたところ、Ｃ／Ｃコンポジット製部材を複数直列にねじ接合することで、光ファイバ用母材やロッドが安定に支持できることを見出して、本発明を完成したものである。すなわち、
【０００７】
本発明は、高純度で、耐熱性、耐荷重性及び加工性に優れ、且つ光ファイバ用母材やロッドを安定に支持できる比較的安価な光ファイバ製造用支持体を提供することを目的とする。
【０００８】
前記目的を達成する本発明は、光ファイバ用母材を加熱延伸するロッドの製造工程及び／又は前記ロッドを線引きする線引き工程で使用する光ファイバ製造用支持体において、該支持体が２つ以上の円柱状又は円筒状のＣ／Ｃコンポジット製部材がねじ部で直列に接合されたものからなることを特徴とする光ファイバ製造用支持体に係る。
【０００９】
上述のように本発明の光ファイバ製造用支持体は、Ｃ／Ｃコンポジットからなる円柱状又は円筒状の部材が２個以上直列にねじ接合された支持体であり、そのＣ／Ｃコンポジットは、かさ密度が１．５ｇ／ｃｍ³以上、曲げ強度が１００ＭＰａ以上、引張り強さが１００ＭＰａ以上のものがよい。Ｃ／Ｃコンポジットが前記範囲未満では、十分な強度が得られず、大型で長尺な光ファイバ用母材やロッドを支持する部材として使用した場合に破損等が発生するおそれがあり好ましくない。このＣ／Ｃコンポジットは、例えば炭素繊維クロスにピッチ又は樹脂を含浸させたプリプレグを複数枚積層し平板形状に成形する。その後、焼成による炭素化処理、ピッチ又は樹脂を再度含浸して焼成する等の緻密化処理、黒鉛化処理を行い、さらにハロゲンガスを用いて高純度化処理して製造される。Ｃ／Ｃコンポジット中の不純物は、Ｎａ、Ｋ、Ｆｅ等が１ｐｐｍ以下であるのが好ましい。これにより光ファイバ用母材の加熱延伸工程や光ファイバ用ロッドの線引き工程において前記支持体を使用した場合においても、支持体や雰囲気等を経由しての不純物による汚染が抑制され、高純度な光ファイバを得ることができ、伝送特性の損失が少ない良好な光ファイバが製造できる。
【００１０】
前記支持体はねじ部で直列に接合されるが、使用するねじとしては断面形状の違いに基づいて「台形ねじ」、「三角ねじ」、「角ねじ」、「のこ歯ねじ」等が挙げられるが、中でも台形ねじは雄ねじと雌ねじとの接触面積が大きく耐荷重性が高く、なお且つねじ加工や接合などの作業性にも優れて好適である。
【００１１】
本発明に係る支持体は、光ファイバ用母材を加熱延伸するロッドの製造工程、又は前記ロッドを線引きして光ファイバとする工程、もしくはその両方の工程に用いることができる。該光ファイバ用母材としては、前記軸付け法、外付け法、ＭＣＶＤ法、ゾルゲル法、又はそれらを（ＲＩＴ／ＲＩＣ法等、オーバークラッディング工程他を用いて）組み合わせて得られた光ファイバ用母材を用いることができる。
【００１２】
【発明の実施の形態】
以下、添付図に基づき、本発明に係る実施態様の一例について説明する。図１は台形ねじで直列に接合した支持体の接合部の概略断面図である。図１において、１は両端のうち一方の側に雄ねじを設けたＣ／Ｃコンポジット製ロッド、２は両端のうち一方の側に雌ねじを設けたＣ／Ｃコンポジット製ロッド、３はＣ／Ｃコンポジット製ロッド１の雄ねじ部、４はＣ／Ｃコンポジット製ロッド２の雌ねじ部である。このＣ／Ｃコンポジット製ロッドのねじ部に炭素の含浸及び／又は被覆を施した層５を有する支持体の接合部の概略断面図を図２に示す。この支持体はねじ部の強度が一段と向上し、外径３０ｍｍのロッドにおける引張り強さが黒鉛製ロッドの約４倍にも達する。そのため、多孔質石英ガラス母材が大型化、長尺化しても、ねじ部での破損が起こることがさらに低減される。また、ねじ部を補強するために図３に示すようにねじ部外周にＣ／Ｃコンポジット製の補強部材６を設けるのがよい。このＣ／Ｃコンポジット製補強部材６を設けることでねじ接合部の補強が一層強固となり、ねじ部の熱膨張やねじ部の接触面積の減少が抑制でき、さらに高い精度の高純度な光ファイバ用ロッドや光ファイバが製造できる。前記補強部材を形成するＣ／Ｃコンポジットは、例えば炭素繊維にピッチ又は樹脂を含浸させたプリプレグを円柱状の支持体の上に巻つけ、円筒状に形成する。その後、前述の炭素化処理、緻密化処理、黒鉛化処理、高純度化処理を行い、さらに炭素の含浸及び／又は被覆が施された層を設けて製造される。前記炭素の含浸及び／又は被覆により補強部材からのパーティクルの発生が抑えられ、一段と高純度の石英ガラス体が得られる。補強部材はまた炭素の含浸及び／又は被覆を施さないＣ／Ｃコンポジットで形成することもできる。
【００１３】
前記炭素の含浸及び／又は被覆が施された層とは、炭化水素系ガスなどを使ったＣＶＩ処理及び／又はＣＶＤ処理、もしくは樹脂の含浸・被覆、硬化、焼成処理等を施すことによって、Ｃ／Ｃコンポジットに、（ｉ）ＣＶＩ処理で熱分解炭素が表面から気孔内部へと含浸・被覆されるか又は樹脂の処理等でガラス状炭素などの物質が含浸されることにより形成された層、（ｉｉ）ＣＶＤ処理で熱分解炭素が表面に被覆されるか又は樹脂の処理等でガラス状炭素などの物質が表面に被覆されることにより形成された層、又は（ｉｉｉ）ＣＶＩ処理で熱分解炭素が表面から気孔内部へと含浸・被覆されるか又は樹脂の処理等でガラス状炭素などの物質が含浸され、なおかつその表面にＣＶＤ処理で熱分解炭素が被覆されるか又は樹脂の処理等でガラス状炭素などの物質が表面に被覆されることにより形成された層、をいう。なお、前記「含浸」と「被覆」にあたっては、これらの層の形成の工程前後に、必要に応じて機械的な表面処理や仕上げ加工を行なうことは、工業的に通常行なわれることである。
【００１４】
支持体を備えた加熱延伸装置の概略断面図を図５に、また線引き装置の概略断面図を図６に示す。図５において、１１は支持体、１２は光ファイバ用母材、１３は接合部、１４はヒーター、１５は延伸ローラー、１６は光ファイバ用ロッド、１７は昇降手段である。また、図６において、１１は支持体、１３は接合部、１６は光ファイバ用ロッド、１７は昇降手段、１８は線引き用ヒーター、１９は線引きローラー、２０は光ファイバ、２１は巻取りドラムである。ＯＶＤ法やＶＡＤ法で製造した光ファイバ用母材１２は光ファイバ製造用支持体１１の接合部１３に端部で接続され、回転可能に吊された状態で加熱延伸炉内にセットされ、炉内を不活性ガス雰囲気にして、ヒーター１４で加熱しながら、延伸ローラー１５で引き下げ外径が数分の一のロッド１６に延伸される。次いで、前記ロッドは接合部１３を介して支持体１１に接続され、昇降手段１７に回転可能に吊された状態で、線引き装置にセットされ、不活性ガス雰囲気中で線引き用ヒーター１８で加熱され、線引きローラー１９で光ファイバ２０に線引きされ、巻取りドラム２１に巻き取られる。
【００１５】
次に具体例をあげて本発明を詳細に説明するが、これらの実施例は例示的に示されるものであって、本発明はそれにより限定されるものではない。
【００１６】
実施例１
東レ（株）製の炭素繊維（トレカＴ−３００）の６Ｋ平織りクロスにフェノール樹脂を含浸させてプリプレグを製造し、約８２０ｍｍ×４１０ｍｍに裁断して積層し、１６０℃で熱圧プレス成形を行って、約８２０ｍｍ×４１０ｍｍ×３５ｍｍのサイズの成形体を得た。この成形体を、電気炉内で８００℃まで昇温して加熱し、焼成体を得た。その焼成体にピッチ含浸と焼成を繰り返し行って緻密化した後、２０００℃で熱処理して、約８２０ｍｍ×４１０ｍｍ×３５ｍｍの平板状のＣ／Ｃコンポジットを得た。このＣ／Ｃコンポジット平板の物性値を測定したところ、かさ密度１．６２ｇ／ｃｍ³、曲げ強さ１５５ＭＰａ、引張り強さ２２０ＭＰａであった。この平板から、長さ８００ｍｍ、直径３０ｍｍφの円柱ロッドを１２本作製し、そのうち２本のロッドについて、１本の端部外周を研削により端面から５０ｍｍ長さまで台形型雄ねじとする一方、もう一本の端部内周を研削により台形型雌ねじとし、ハロゲンガスによる高純度化処理を行った後、２本を直列に繋ぎ合わせて接合し、長さ１５５０ｍｍ、直径３０ｍｍφのＣ／Ｃコンポジット製支持体を得た。得られた支持体を引張り試験装置に取り付け、変移速度０．５ｍｍ／ｍｉｎの静的引張り荷重にて、破断荷重の測定を行った。その結果、ねじ山が破断し、その時の破断荷重は１４２００Ｎ（ニュートン）であった。
【００１７】
さらに、残りの１０本のロッドについて、前記と同様に台形型雄ねじと台形型雌ねじを設けた（ここでは、１本のロッドには１端側に雄ねじのみを、８本については１端側に雄ねじ、その反対側に雌ねじを、残りの１本のロッドには１端側に雌ねじのみを、それぞれ設けた）後、ハロゲンガスによる高純度化処理を行った。そして、それらの１０本のロッドを、前記と同様に雄ねじと雌ねじとにより９箇所を接合して、長さ７５５０ｍｍ、直径３０ｍｍφのＣ／Ｃコンポジット製支持体Ａを得た。
【００１８】
一方、軸付け法を用いて、ゲルマニウムが含有されたコア部と、純粋な石英からなるクラッド部とをそなえた多孔質石英ガラス母材を作製し、脱水、ガラス化して、重量約３５０ｋｇの光ファイバ用母材１２を得た。
【００１９】
得られた光ファイバ用母材１２を前記光ファイバ用支持体Ａ（１１）の端部の接合部１３に取り付け、図５に示す加熱延伸炉内にセットして、不活性ガスを流しながらヒーター１４で１９３０℃に加熱し、延伸ローラー１５で延伸して直径４０ｍｍφの光ファイバ用ロッド１６を形成した。前記延伸中に中心ブレはなく、得られたロッドには偏心がみられなかった。
【００２０】
前記ロッド１６を支持体Ａ（１１）を介して吊し、図６に示す線引き装置内にセットして、線引きローラー１９で光ファイバ２０に線引きし、巻取りドラム２１に巻き取った。得られた光ファイバには偏心がみられなかった。
【００２１】
実施例２
実施例１と同様に、長さ８００ｍｍ、直径３０ｍｍφの円柱ロッドを１２本作製した。そのうち２本のロッドについて、１本の端部外周を研削により端面から５０ｍｍ長さまで台形型雄ねじとする一方、もう１本の端部内周を研削により台形型雌ねじとした。これらのねじ部が形成された２本のロッドについて、ハロゲンガスによる高純度化処理を行った後、気相蒸着炉に入れ、ＣＶＩ処理により熱分解炭素の含浸・被覆を行ない、その２本のロッドを直列に繋ぎ合わせて接合して、長さ１５５０ｍｍ、直径３０ｍｍφのＣ／Ｃコンポジット製支持体を得た。得られたＣ／Ｃコンポジット製支持体について、実施例１と同様に静的引張り荷重による破断荷重の測定を行ったところ、ねじ山が破断し、その時の破断荷重は１６７００Ｎであった。
【００２２】
さらに、残りの１０本のロッドについて、前記と同様に台形型雄ねじと台形型雌ねじを設けた（ここでは、１本のロッドには１端側に雄ねじのみを、８本については１端側に雄ねじ、その反対側に雌ねじを、残りの１本のロッドには１端側に雌ねじのみを、それぞれ設けた）後、ハロゲンガスによる高純度化処理を行った。そして、それらの１０本のロッドを、前記と同様に雄ねじと雌ねじとにより９箇所を接合して、長さ７５５０ｍｍ、直径３０ｍｍφのＣ／Ｃコンポジット製支持体Ｂを得た。
【００２３】
一方、軸付け法を用いて、ゲルマニウムが含有されたコア部と、純粋な石英からなるクラッド部とをそなえた多孔質石英ガラス母材１２を作製し、脱水、ガラス化して、重量約３５０ｋｇの光ファイバ用母材１２を得た。
【００２４】
得られた光ファイバ用母材１２を前記光ファイバ用支持体Ｂ（１１）の端部の接続部に取り付け、図５に示す加熱延伸炉内にセットして、不活性ガスを流しながらヒーター１４で１９３０℃に加熱し、延伸ローラー１５で延伸して直径４０ｍｍφの光ファイバ用ロッド１６を形成した。前記延伸中に中心ブレはなく、得られたロッドには偏心がみられなかった。
【００２５】
前記ロッドを支持体Ｂ（１１）を介して吊し、図６に示す線引き装置内にセットして、線引きローラー１９で光ファイバ２０に線引きし、巻取りドラム２１に巻き取った。得られた光ファイバには偏心がみられなかった。
【００２６】
実施例３
実施例１及び２と同様に、長さ８００ｍｍ、直径３０ｍｍφの円柱ロッドを１２本作製し、そのうち２本のロッドについて、１本の端部外周を研削により端面から５０ｍｍ長さまで台形型雄ねじとする一方、もう１本の端部内周を研削により台形型雌ねじとした。次いで、前記雌ねじ部の外周部分を深さ１ｍｍ、長さ３０ｍｍ分切削した。これはその切削部分に、円周で補強するための円筒形状のＣ／Ｃコンポジット製補強部材を取り付けるためのものである。これらのねじ部が形成された２本のロッドについて、ハロゲンガスによる高純度化処理を行った後、気相蒸着炉に入れ、ＣＶＩ処理により熱分解炭素の含浸・被覆を行い、その２本のロッドを直列に繋ぎ合わせて接合し、長さ１５５０ｍｍ、直径３０ｍｍφのＣ／Ｃコンポジット製支持体を得た。前記補強部材は、東レ（株）製の炭素繊維（トレカＴ−３００）１２Ｋフィラメントをフィラメントワインディング装置によりフェノール樹脂を含浸しながらシリンダー形状に成形し、その成形体にピッチ含浸、焼成を数回繰り返し緻密化を行なった後、２０００℃で熱処理を行った。このシリンダー形状品を幅２０ｍｍに切断し内部に２分割の金属治具を挿入し、引張り試験機を用い上下に引張る方法で引張り強さを測定したところ３００ＭＰａの強度があった。前記補強部材は、Ｃ／Ｃコンポジット製支持体の雌ねじ部外周の切削部分に合うように内外径、長さを加工し作製したものであり、図３に示したように雌ねじ部外周の切削部分に篏合した。前記補強部材には、さらに、実施例２と同様に、ハロゲンガスによる高純度化処理及び熱分解炭素の含浸・被覆を施した。得られたＣ／Ｃコンポジット製支持体について、実施例１及び２と同様に静的引張り荷重による破断荷重の測定を行ったところ、ねじ山が破断し、その時の破断荷重は２１０００Ｎであった。
【００２７】
さらに、残りの１０本のロッドについて、ハロゲンガスによる高純度化処理を行った後、前記と同様にＣＶＩ処理によりねじ部に熱分解炭素の含浸・被覆を行い、前記と同様に台形型雄ねじと円筒形状のＣ／Ｃコンポジット製補強部材が取り付けられた台形型雌ねじにより、実施例１及び２の支持体と同様に９箇所を接合して、長さ７５５０ｍｍ、直径３０ｍｍφのＣ／Ｃコンポジット製支持体Ｃを得た。
【００２８】
一方、軸付け法を用いて、ゲルマニウムが含有されたコア部と、純粋な石英からなるクラッド部とをそなえた多孔質石英ガラス母材を作製し、脱水、ガラス化して、重量約３５０ｋｇの光ファイバ用母材１２を得た。
【００２９】
得られた光ファイバ用母材１２を前記光ファイバ用支持体Ｃ（１１）の端部の接続部に取り付け、図５に示す加熱延伸炉内にセットして、不活性ガスを流しながらヒーター１４で１９３０℃に加熱し、延伸ローラー１５で延伸して直径４０ｍｍφの光ファイバ用ロッド１６を形成した。前記延伸中に中心ブレはなく、得られたロッドには偏心がみられなかった。
【００３０】
前記ロッドを支持体Ｃ（１１）を介して吊し、図６に示す線引き装置内にセットして、線引きローラー１９で光ファイバ２０に線引きし、巻取りドラム２１に巻き取った。得られた光ファイバには偏心がみられなかった。
【００３１】
比較例１
長さ８００ｍｍ、直径３０ｍｍφの円柱ロッドを、高純度等方性高密度黒鉛（商品名ＩＳＯ−６３０、東洋炭素（株）製）で１２本作製し、そのうち２本のロッドを台形型雄ねじと台形型雌ねじにより直列に繋ぎ合わせ、長さ１５５０ｍｍ、直径３０ｍｍφの高純度等方性高密度黒鉛製支持体を得た。使用した高純度等方性高密度黒鉛のかさ密度は１．８２ｇ／ｃｍ³、引張り強さは５３．９ＭＰａであり、灰分は１０ｐｐｍ以下であった。得られた支持体について、実施例１〜３と同様に静的引張り荷重による破断荷重の測定を行ったところ、ねじ山が破断し、その時の破断荷重は３９００Ｎであった。さらに、残りの１０本のロッドについて、高純度化処理を行った後、台形型雄ねじと台形型雌ねじにより９箇所を接合し、長さ７５５０ｍｍ、直径３０ｍｍφの高純度等方性高密度黒鉛製支持体Ｄを得た。
【００３２】
一方、軸付け法を用いて、ゲルマニウムが含有されたコア部と、純粋な石英からなるクラッド部とをそなえた多孔質石英ガラス母材を作製し、脱水、ガラス化して、重量約３５０ｋｇの光ファイバ用母材１２を得た。
【００３３】
得られた光ファイバ用母材１２を前記光ファイバ用支持体Ｄ（１１）の端部の接続部に取り付け、図５に示す加熱延伸炉内にセットして、不活性ガスを流しながらヒーター１４で１９３０℃に加熱し、延伸ローラー１５で延伸したところ、支持体Ｄ（１１）に弓状の変形が生じ、得られたロッドには偏心がみとめられた。
【００３４】
比較例２
実施例１〜３と同様に、長さ８００ｍｍ、直径３０ｍｍφの円柱ロッドを１２本作製した。次いで、そのうち２本のロッドを用いて、図４に示すような、１本の円柱ロッド７の端部にスリット１０加工を施し、もう１本の円柱ロッドに挿入し、ピン挿入孔８を設けピン９を挿入して２本のロッドを固定し、長さ１５５０ｍｍ、直径３０ｍｍφのＣ／Ｃコンポジット製支持体を得た。得られた支持体について、実施例１〜３と同様に静的引張り荷重による破断荷重の測定を行ったところ、ピンが破断し、その時の破断荷重は９５００Ｎであった。さらに、残りの１０本のロッドについて、高純度化処理を行なった後、前記と同様にピン固定により９箇所を繋ぎ合わせ、長さ７５５０ｍｍ、直径３０ｍｍφのＣ／Ｃコンポジット製支持体Ｅを得た。
【００３５】
一方、軸付け法を用いて、ゲルマニウムが含有されたコア部と、純粋な石英からなるクラッド部とをそなえた多孔質石英ガラス母材を作製し、脱水、ガラス化して、重量約３５０ｋｇの光ファイバ用母材１２を得た。
【００３６】
得られた光ファイバ用母材１２を前記光ファイバ用支持体Ｅ（１１）の端部の接続部に取り付け、図５に示す加熱延伸炉内にセットして、不活性ガスを流しながらヒーター１４で１９３０℃に加熱し、延伸ローラー１５で延伸したところ、支持体Ｅ（１１）のピン固定部で曲がりが生じ、得られたロッドには偏心がみとめられた。
【００３７】
【発明の効果】
本発明の光ファイバ製造用支持体は、高純度で、耐熱性とともに耐荷重性が高く、且つ加工性に優れたものであり、大型の光ファイバ用母材やロッドであっても安定に支持し加熱延伸や線引きを行なうことができる。この光ファイバ製造用支持体を用いて光ファイバを製造することにより、偏心がなく高精度で高品質の光ファイバが、低コストで生産性よく製造できる。
【図面の簡単な説明】
【図１】本発明の支持体の接合部の概略断面図である。
【図２】ねじ部に炭素の含浸及び／又は被覆が施された支持体の接合部の概略断面図である。
【図３】ねじ部外周に補強部材が設けられた支持体の接合部の概略断面図である。
【図４】ピン固定で直列に繋ぎ合わせた支持体の接合部の概略断面図である。
【図５】本発明の光ファイバ製造用支持体を用いた加熱延伸装置の概略断面図である。
【図６】本発明の光ファイバ製造用支持体を用いた線引き装置の概略断面図である。
【符号の説明】
１ロッド（一方の端側に雄ねじを設けたロッド）
２ロッド（一方の端側に雌ねじを設けたロッド）
３ロッド１の雄ねじ部
４ロッド２の雌ねじ部
５炭素の含浸及び／又は被覆が施された層
６Ｃ／Ｃコンポジット製の補強部材
７ロッド（一方の端側にスリットを設けたロッド）
８ピン挿入孔
９ピン
１０スリット
１１支持体
１２光ファイバ用母材
１３接合部
１４ヒーター
１５延伸ローラー
１６光ファイバ用ロッド
１７昇降手段
１８線引き用ヒーター
１９線引きローラー
２０光ファイバ
２１巻取りドラム[0001]
[Industrial application fields]
The present invention relates to a support for manufacturing an optical fiber, more specifically, an optical fiber for manufacturing an optical fiber stably, accurately and with high productivity from a large optical fiber preform prepared by an OVD method, a VAD method or the like. The present invention relates to a support.
[0002]
[Prior art]
Conventionally, an optical fiber rotates a columnar or cylindrical heat-resistant substrate having a smooth outer peripheral surface, sprays and attaches silica glass fine particles to the surface, and forms a porous quartz glass base material. The porous quartz glass base material on the mold body is heated to become transparent glass (Outside Vapor Deposition Method, hereinafter referred to as “external method”), and quartz glass fine particles are deposited in the axial direction of the seed rod to be porous. Optical fiber preform made by a vapor-phase axial deposition method (hereinafter referred to as “shafting method”) in which a porous quartz glass preform is formed and heated to become transparent glass. After heating and drawing to about a fraction of a rod, it is drawn into a single-mode optical fiber with an outer diameter of 125 μm using a drawing machine. It has been manufactured. In recent years, if practical use of single-mode optical fibers has progressed and a large number of optical fibers have been used, and the range of use of optical fibers has expanded to general subscriber systems, the amount of future use can further increase. It is predicted. In order to increase the amount of optical fiber used, mass production and cost reduction are indispensable. As one of effective means for that purpose, large and long porous quartz can be obtained by a shafting method that has been put to practical use. It is considered effective to prepare a glass preform, dehydrate it and convert it to transparent glass to produce a large and long optical fiber preform, and heat-draw and draw it.
[0003]
[Problems to be solved by the invention]
However, the weight of the optical fiber base material and the rod obtained by heating and stretching it increase in size and length, and the optical fiber base material and the member supporting the rod (such as a dummy rod or Although it is sometimes called a dummy shaft or the like, in this case, it is also necessary to increase the length of the “support”, and its weight further increases. In addition, when the optical fiber preform and rod are enlarged and lengthened, the temperature at the time of heating and drawing becomes high. Until now, a quartz glass support has been used as a support for optical fiber preforms and rods used in the heating and drawing process. Quartz glass is a high-purity and good workability, so it can be obtained with high dimensional accuracy and can withstand relatively high temperatures. If an attempt is made to increase the size and length of the substrate, the weight applied to the support will inevitably become larger and the temperature will become higher, and the support made of quartz glass will have insufficient load bearing strength. In addition, the handling requires careful attention to avoid breakage such as cracks and cracks due to glass, and the handling burden and damage risk in handling are much higher than those of conventional small components. Will increase. Therefore, a method of adding a disposable quartz glass member to the end of the quartz glass support and cutting and discarding a portion where deformation due to high temperature has occurred has been used. However, since this disposable quartz glass member is also made of glass, sufficient load resistance cannot be obtained, and since quartz glass is disposable, there is a problem that the cost cannot be reduced sufficiently. It was. In addition to ceramics such as alumina, zirconia, mullite, silicon nitride, and silicon carbide, a support made of graphitized carbon material (graphite carbon) is also proposed as a support to solve such problems such as load resistance and heat resistance. However, high-purity ceramics with excellent heat resistance are very expensive and difficult to work with, so if you want to obtain a high-precision ceramic support, it is necessary to perform significant grinding, etc. This increases the manufacturing cost.
[0004]
In addition, carbon materials such as graphite, which are relatively inexpensive, excellent in heat resistance and workability, and easy to handle, are also large and long optical fiber base materials that have insufficient strength compared to conventional carbon materials. It has been difficult to realize a rod that can withstand the load when the rod is heated and drawn.
[0005]
In recent years, carbon fiber reinforced carbon composite as a material that has excellent workability, load resistance and heat resistance, and is easy to handle, but also superior in price and capable of high purity products. Materials (Carbon Fiber Rein-forged Carbon Composites, hereinafter referred to as “C / C composites”) have been proposed and put into practical use. However, C / C composites should be practically manufactured with a length exceeding 1000 mm or an outer diameter exceeding 100 mm due to problems in production such as synthesis and molding, or problems in processing accuracy. Is very difficult, and in order to be used as a support during heating and drawing or drawing, it is necessary to lengthen the length by joining a plurality of rod members in series. As the lengthening by this joining, a method using various various jigs such as making a hole near the end of the rod and locking with a joining pin can be considered, but the optical fiber preform or rod As the size increases and the load increases, the locking by the joining pin cannot withstand an excessive load and the pin may be damaged. If the joining pins are damaged, the joining is incomplete, so that the dimensional accuracy of the support is impaired, and it becomes impossible to obtain the optical fiber rod having a desired shape. Furthermore, as shown in FIG. 4, in the case of locking with a pin, the diameter of the insertion hole of the pin must be larger than the diameter of the pin itself for handling, so between the pin and its insertion hole. As a result, there was a gap, which generated “gap” and the support itself was bent, causing the eccentricity of the optical fiber.
[0006]
[Means for Solving the Problems]
In view of such a current situation, the present inventors have conducted intensive research, and as a result, the C / C composite can be produced with high purity, has excellent heat resistance and workability, and is relatively inexpensive. Considering that it is best to produce a support for optical fiber production with a C / C composite, and made efforts to improve the support for optical fiber production made of conventional C / C composite, The present invention has been completed by finding that the optical fiber preform and rod can be stably supported by screw joining in series. That is,
[0007]
An object of the present invention is to provide a relatively inexpensive support for manufacturing an optical fiber that has high purity, is excellent in heat resistance, load resistance, and workability, and that can stably support an optical fiber preform and a rod. To do.
[0008]
The present invention that achieves the above object provides a support for manufacturing an optical fiber that is used in a manufacturing process of a rod for heating and drawing an optical fiber preform and / or a drawing process for drawing the rod. It is related with the support body for optical fiber manufacture characterized by consisting of what the column-shaped or cylindrical C / C composite-made member was joined in series by the thread part.
[0009]
As described above, the support for manufacturing an optical fiber of the present invention is a support in which two or more columnar or cylindrical members made of a C / C composite are screwed in series, and the C / C composite is It is preferable that the bulk density is 1.5 g / cm ³ or more, the bending strength is 100 MPa or more, and the tensile strength is 100 MPa or more. If the C / C composite is less than the above range, sufficient strength cannot be obtained, and there is a possibility that breakage or the like may occur when used as a member that supports a large and long optical fiber preform or rod. In this C / C composite, for example, a plurality of prepregs in which a carbon fiber cloth is impregnated with pitch or resin are laminated and formed into a flat plate shape. Thereafter, carbonization treatment by firing, densification treatment such as re-impregnation with pitch or resin and firing, and graphitization treatment are performed, and further, purification is performed using a halogen gas. As for the impurities in the C / C composite, Na, K, Fe and the like are preferably 1 ppm or less. As a result, even when the support is used in the heating and drawing process of the optical fiber preform and the drawing process of the optical fiber rod, contamination by impurities via the support or the atmosphere is suppressed, and high purity is achieved. An optical fiber can be obtained, and a good optical fiber with little loss of transmission characteristics can be manufactured.
[0010]
The support is joined in series at the threaded portion, but as the screws to be used, “trapezoidal screw”, “triangular screw”, “square screw”, “sawtooth screw”, etc. are mentioned based on the difference in cross-sectional shape In particular, trapezoidal screws are suitable because they have a large contact area between male and female screws, have high load resistance, and are excellent in workability such as threading and joining.
[0011]
The support according to the present invention can be used in a process for producing a rod for heating and stretching an optical fiber preform, or a process for drawing an optical fiber by drawing the rod, or both processes. As the optical fiber base material, an optical fiber obtained by using the above-described shaft attachment method, external attachment method, MCVD method, sol-gel method, or a combination thereof (using an overcladding process or the like such as an RIT / RIC method). A base material can be used.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic sectional view of a joint portion of a support body joined in series with a trapezoidal screw. In FIG. 1, 1 is a C / C composite rod provided with a male screw on one side of both ends, 2 is a C / C composite rod provided with a female screw on one side of both ends, and 3 is a C / C composite. A male threaded portion 4 of the rod 1 made of steel and a female threaded portion 4 of the rod 2 made of C / C composite. FIG. 2 shows a schematic cross-sectional view of the joint portion of the support having the layer 5 in which the thread portion of the C / C composite rod is impregnated and / or coated with carbon. The strength of the support is further improved, and the tensile strength of a rod having an outer diameter of 30 mm is about four times that of a graphite rod. Therefore, even if the porous quartz glass base material is enlarged and lengthened, the occurrence of breakage at the thread portion is further reduced. In order to reinforce the threaded portion, it is preferable to provide a reinforcing member 6 made of C / C composite on the outer periphery of the threaded portion as shown in FIG. By providing this C / C composite reinforcing member 6, the reinforcement of the threaded joint is further strengthened, the thermal expansion of the threaded portion and the reduction of the contact area of the threaded portion can be suppressed, and the optical fiber with higher accuracy and high purity can be used. Rods and optical fibers can be manufactured. The C / C composite forming the reinforcing member is formed into a cylindrical shape by, for example, winding a prepreg obtained by impregnating carbon fiber with pitch or resin on a columnar support. Thereafter, the carbonization treatment, the densification treatment, the graphitization treatment, and the high-purification treatment described above are performed, and a carbon impregnated and / or coated layer is provided. Generation of particles from the reinforcing member is suppressed by the impregnation and / or coating of carbon, and a quartz glass body with higher purity can be obtained. The reinforcing member can also be formed of a C / C composite without carbon impregnation and / or coating.
[0013]
The carbon impregnated and / or coated layer is formed by performing CVI treatment and / or CVD treatment using a hydrocarbon gas or the like, or impregnating / coating resin, curing, baking treatment, etc. / C composite, (i) a layer formed by impregnating / coating pyrolytic carbon from the surface into the pores by CVI treatment or impregnating a material such as glassy carbon by resin treatment, (Ii) a layer formed by coating pyrolytic carbon on the surface by CVD treatment or coating a surface of a material such as glassy carbon by resin treatment or the like, or (iii) pyrolysis by CVI treatment Carbon is impregnated and coated from the surface to the inside of the pores, or a glassy carbon or the like is impregnated by resin treatment, etc., and the surface is coated with pyrolytic carbon or resin treatment, etc. In It refers to a layer, which is formed by substances, such as scan-like carbon is coated on the surface. In the above-mentioned “impregnation” and “coating”, mechanical surface treatment and finishing as required before and after the formation of these layers are usually carried out industrially.
[0014]
FIG. 5 shows a schematic cross-sectional view of a heating and stretching apparatus provided with a support, and FIG. 6 shows a schematic cross-sectional view of a drawing apparatus. In FIG. 5, 11 is a support, 12 is an optical fiber preform, 13 is a joint, 14 is a heater, 15 is a drawing roller, 16 is an optical fiber rod, and 17 is an elevating means. In FIG. 6, 11 is a support, 13 is a joint, 16 is an optical fiber rod, 17 is lifting means, 18 is a drawing heater, 19 is a drawing roller, 20 is an optical fiber, and 21 is a winding drum. is there. The optical fiber preform 12 manufactured by the OVD method or the VAD method is connected to the joint 13 of the optical fiber manufacturing support 11 at the end, and is set in a heating and drawing furnace in a state of being rotatably suspended. The inside is made into an inert gas atmosphere, and while being heated by the heater 14, it is pulled down by the stretching roller 15 and stretched to the rod 16 having a fraction of an outer diameter. Next, the rod is connected to the support 11 via the joint 13 and is set in a drawing device while being rotatably suspended by the lifting means 17 and heated by a drawing heater 18 in an inert gas atmosphere. The optical fiber 20 is drawn by a drawing roller 19 and wound on a winding drum 21.
[0015]
Next, the present invention will be described in detail with reference to specific examples. However, these examples are illustrative and the present invention is not limited thereby.
[0016]
Example 1
Carbon fiber (Torayca T-300) 6K plain weave cloth made by Toray Industries, Inc. is impregnated with phenolic resin to produce a prepreg, cut and laminated to about 820mm x 410mm, and hot press molding at 160 ° C. Thus, a molded body having a size of about 820 mm × 410 mm × 35 mm was obtained. This molded body was heated to 800 ° C. in an electric furnace and heated to obtain a fired body. The fired body was subjected to pitch impregnation and firing repeatedly to be densified, and then heat treated at 2000 ° C. to obtain a flat C / C composite of about 820 mm × 410 mm × 35 mm. When the physical properties of the C / C composite flat plate were measured, the bulk density was 1.62 g / cm ³ , the bending strength was 155 MPa, and the tensile strength was 220 MPa. From this flat plate, twelve cylindrical rods having a length of 800 mm and a diameter of 30 mmφ were produced. Of these two rods, the outer periphery of one end was ground to a trapezoidal male screw from the end face to a length of 50 mm, while another The inner periphery of the end is made into a trapezoidal female thread by grinding, and after purifying with a halogen gas, the two are connected in series and joined to form a C / C composite support having a length of 1550 mm and a diameter of 30 mmφ. Obtained. The obtained support was attached to a tensile test apparatus, and the breaking load was measured with a static tensile load having a transition speed of 0.5 mm / min. As a result, the thread ruptured, and the rupture load at that time was 14200 N (Newton).
[0017]
Further, the remaining 10 rods were provided with a trapezoidal male screw and a trapezoidal female screw in the same manner as described above (here, one rod has only one male screw on one end side and eight rods on one end side). The male screw, the female screw on the opposite side, and the female screw on the other end were provided with only the female screw on one end side), followed by high purity treatment with halogen gas. Then, these ten rods were joined at nine locations with male and female screws in the same manner as described above to obtain a support A made of C / C composite having a length of 7550 mm and a diameter of 30 mmφ.
[0018]
On the other hand, a porous quartz glass base material having a core portion containing germanium and a clad portion made of pure quartz is produced using a shafting method, dehydrated and vitrified, and light having a weight of about 350 kg. A fiber preform 12 was obtained.
[0019]
The obtained optical fiber preform 12 is attached to the joint 13 at the end of the optical fiber support A (11), set in the heating and drawing furnace shown in FIG. 5, and heated while flowing an inert gas. 14 was heated to 1930 ° C. and stretched by a stretching roller 15 to form a 40 mmφ optical fiber rod 16. There was no center blurring during the stretching, and no eccentricity was observed in the obtained rod.
[0020]
The rod 16 was suspended via the support A (11), set in a drawing apparatus shown in FIG. 6, drawn on an optical fiber 20 by a drawing roller 19, and wound on a winding drum 21. The obtained optical fiber was not eccentric.
[0021]
Example 2
In the same manner as in Example 1, 12 cylindrical rods having a length of 800 mm and a diameter of 30 mmφ were produced. Of the two rods, the outer periphery of one end was grounded to a trapezoidal male screw up to a length of 50 mm from the end surface, while the inner periphery of the other end was grounded to a trapezoidal female screw. The two rods with these threaded portions were subjected to a high-purity treatment with a halogen gas, then placed in a vapor deposition furnace, and impregnated and coated with pyrolytic carbon by CVI treatment. The rods were connected in series and joined to obtain a C / C composite support having a length of 1550 mm and a diameter of 30 mmφ. The obtained C / C composite support was measured for the breaking load by static tensile load in the same manner as in Example 1. As a result, the thread ruptured and the breaking load at that time was 16700 N.
[0022]
Further, the remaining 10 rods were provided with a trapezoidal male screw and a trapezoidal female screw in the same manner as described above (here, one rod has only one male screw on one end side and eight rods on one end side). The male screw, the female screw on the opposite side, and the female screw on the other end were provided with only the female screw on one end side), followed by high purity treatment with halogen gas. Then, these ten rods were joined at nine locations with male and female screws in the same manner as described above to obtain a support B made of C / C composite having a length of 7550 mm and a diameter of 30 mmφ.
[0023]
On the other hand, a porous quartz glass base material 12 having a core portion containing germanium and a clad portion made of pure quartz is prepared by using a shafting method, and dehydrated and vitrified to have a weight of about 350 kg. An optical fiber preform 12 was obtained.
[0024]
The obtained optical fiber preform 12 is attached to the connecting portion at the end of the optical fiber support B (11), set in the heating and drawing furnace shown in FIG. Was heated to 1930 ° C. and stretched by a stretching roller 15 to form an optical fiber rod 16 having a diameter of 40 mmφ. There was no center blurring during the stretching, and no eccentricity was observed in the obtained rod.
[0025]
The rod was hung through the support B (11), set in a drawing apparatus shown in FIG. 6, drawn on an optical fiber 20 by a drawing roller 19, and taken up on a winding drum 21. The obtained optical fiber was not eccentric.
[0026]
Example 3
In the same manner as in Examples 1 and 2, 12 cylindrical rods having a length of 800 mm and a diameter of 30 mmφ were produced, and the outer periphery of one end of each of the two rods was ground to a trapezoidal male screw from the end face to a length of 50 mm. On the other hand, the inner circumference of the other end was ground to form a trapezoidal female thread. Next, the outer peripheral portion of the female screw portion was cut by a depth of 1 mm and a length of 30 mm. This is for attaching a cylindrical C / C composite reinforcing member to reinforce the circumference of the cut portion. The two rods with these threaded portions were subjected to a high-purity treatment with a halogen gas, then placed in a vapor deposition furnace, and impregnated and coated with pyrolytic carbon by CVI treatment. The rods were connected in series and joined to obtain a C / C composite support having a length of 1550 mm and a diameter of 30 mmφ. The reinforcing member is carbon fiber (Torayca T-300) 12K filament manufactured by Toray Industries, Inc., molded into a cylinder shape while impregnating with a phenol resin with a filament winding device, and the molded body is pitch impregnated and fired several times. After densification, heat treatment was performed at 2000 ° C. This cylinder-shaped product was cut into a width of 20 mm, a two-part metal jig was inserted therein, and the tensile strength was measured by a method of pulling up and down using a tensile tester. As a result, the strength was 300 MPa. The reinforcing member is produced by processing the inner and outer diameters and lengths so as to fit the cutting part on the outer periphery of the female screw part of the support made of C / C composite, and the cutting part on the outer periphery of the female screw part as shown in FIG. I joined. The reinforcing member was further subjected to a high purity treatment with a halogen gas and impregnation / coating with pyrolytic carbon in the same manner as in Example 2. The obtained C / C composite support was measured for the breaking load by static tensile load in the same manner as in Examples 1 and 2. As a result, the thread ruptured and the breaking load at that time was 21000 N.
[0027]
Further, after the remaining 10 rods were subjected to high purity treatment with halogen gas, the screw portion was impregnated and coated with pyrolytic carbon by the CVI treatment in the same manner as described above. A trapezoidal female screw to which a cylindrical C / C composite reinforcing member is attached is used to join 9 points in the same manner as the supports of Examples 1 and 2, and a C / C composite support having a length of 7550 mm and a diameter of 30 mmφ. Body C was obtained.
[0028]
On the other hand, a porous quartz glass base material having a core portion containing germanium and a clad portion made of pure quartz is produced using a shafting method, dehydrated and vitrified, and light having a weight of about 350 kg. A fiber preform 12 was obtained.
[0029]
The obtained optical fiber preform 12 is attached to the connecting portion at the end of the optical fiber support C (11) and set in the heating and drawing furnace shown in FIG. Was heated to 1930 ° C. and stretched by a stretching roller 15 to form an optical fiber rod 16 having a diameter of 40 mmφ. There was no center blurring during the stretching, and no eccentricity was observed in the obtained rod.
[0030]
The rod was suspended via a support C (11), set in a drawing apparatus shown in FIG. 6, drawn on an optical fiber 20 by a drawing roller 19, and wound on a winding drum 21. The obtained optical fiber was not eccentric.
[0031]
Comparative Example 1
Twelve cylindrical rods with a length of 800 mm and a diameter of 30 mmφ are made of high-purity isotropic high-density graphite (trade name ISO-630, manufactured by Toyo Tanso Co., Ltd.), two of which are trapezoidal male screws and trapezoids High-purity isotropic high-density graphite support having a length of 1550 mm and a diameter of 30 mmφ was obtained by connecting in series with a female die. The bulk density of the high purity isotropic high density graphite used was 1.82 g / cm ³ , the tensile strength was 53.9 MPa, and the ash content was 10 ppm or less. About the obtained support body, when the breaking load by a static tensile load was measured like Examples 1-3, the thread ruptured and the breaking load at that time was 3900N. Further, after the high purity treatment was performed on the remaining 10 rods, 9 locations were joined with a trapezoidal male screw and a trapezoidal female screw, and the support was made of high purity isotropic high density graphite having a length of 7550 mm and a diameter of 30 mmφ. Body D was obtained.
[0032]
On the other hand, a porous quartz glass base material having a core portion containing germanium and a clad portion made of pure quartz is produced using a shafting method, dehydrated and vitrified, and light having a weight of about 350 kg. A fiber preform 12 was obtained.
[0033]
The obtained optical fiber preform 12 is attached to the connecting portion at the end of the optical fiber support D (11) and set in the heating and drawing furnace shown in FIG. When heated to 1930 ° C. and stretched by the stretching roller 15, an arcuate deformation occurred in the support D (11), and eccentricity was observed in the obtained rod.
[0034]
Comparative Example 2
In the same manner as in Examples 1 to 3, twelve cylindrical rods having a length of 800 mm and a diameter of 30 mmφ were produced. Next, using two of these rods, the slit 10 is processed at the end of one cylindrical rod 7 as shown in FIG. 4 and inserted into the other cylindrical rod to provide a pin insertion hole 8. The pin 9 was inserted to fix the two rods, and a C / C composite support having a length of 1550 mm and a diameter of 30 mmφ was obtained. About the obtained support body, when the breaking load by a static tensile load was measured similarly to Examples 1-3, the pin broke and the breaking load at that time was 9500N. Further, the remaining 10 rods were subjected to high-purification treatment, and then 9 locations were joined together by pin fixing in the same manner as described above to obtain a C / C composite support E having a length of 7550 mm and a diameter of 30 mmφ. .
[0035]
On the other hand, a porous quartz glass base material having a core portion containing germanium and a clad portion made of pure quartz is produced using a shafting method, dehydrated and vitrified, and light having a weight of about 350 kg. A fiber preform 12 was obtained.
[0036]
The obtained optical fiber preform 12 is attached to the connecting portion at the end of the optical fiber support E (11) and set in the heating and drawing furnace shown in FIG. When heated to 1930 ° C. and stretched by the stretching roller 15, bending occurred at the pin fixing portion of the support E (11), and eccentricity was observed in the obtained rod.
[0037]
【The invention's effect】
The optical fiber manufacturing support of the present invention has high purity, high heat resistance, high load resistance, and excellent workability, and stably supports even large optical fiber preforms and rods. Heat drawing and drawing can be performed. By manufacturing an optical fiber using this optical fiber manufacturing support, it is possible to manufacture a high-precision and high-quality optical fiber without eccentricity at low cost and with high productivity.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a joint portion of a support according to the present invention.
FIG. 2 is a schematic cross-sectional view of a joint portion of a support body in which a thread portion is impregnated and / or coated with carbon.
FIG. 3 is a schematic cross-sectional view of a joint portion of a support body in which a reinforcing member is provided on the outer periphery of a screw portion.
FIG. 4 is a schematic cross-sectional view of a joint portion of a support body connected in series by pin fixing.
FIG. 5 is a schematic cross-sectional view of a heating and stretching apparatus using the support for producing an optical fiber of the present invention.
FIG. 6 is a schematic cross-sectional view of a drawing apparatus using the optical fiber manufacturing support of the present invention.
[Explanation of symbols]
1 Rod (Rod with a male thread on one end)
2 Rod (Rod with internal thread on one end)
3 Male thread part 4 of rod 1 Female thread part 5 of rod 2 Carbon 6 impregnated and / or coated layer 6 C / C composite reinforcing member 7 Rod (rod with a slit on one end side)
8 Pin insertion hole 9 Pin 10 Slit 11 Support 12 Base material for optical fiber 13 Joint portion 14 Heater 15 Drawing roller 16 Optical fiber rod 17 Lifting means 18 Drawing heater 19 Drawing roller 20 Optical fiber 21 Winding drum

Claims

光ファイバ用母材を加熱延伸するロッド製造工程及び／又は前記ロッドを線引きする線引き工程で使用する光ファイバ製造用支持体において、該支持体が２つ以上の円柱状又は円筒状の炭素繊維強化炭素複合材料製部材がねじ部で直列に接合されたものからなることを特徴とする光ファイバ製造用支持体。In a rod manufacturing process for heating and drawing an optical fiber preform and / or an optical fiber manufacturing support used in a drawing process for drawing the rod, the support is reinforced with two or more cylindrical or cylindrical carbon fibers. A support for producing an optical fiber, comprising carbon composite material members joined in series at a threaded portion.

炭素繊維強化炭素複合材料製部材を接合するねじ部が台形ねじであることを特徴とする請求項１記載の光ファイバ製造用支持体。2. The support for manufacturing an optical fiber according to claim 1, wherein the threaded portion for joining the carbon fiber reinforced carbon composite material members is a trapezoidal screw.

ねじ部に炭素の含浸及び／又は被覆が施されていることを特徴とする請求項１又は２記載の光ファイバ製造用支持体。The support for manufacturing an optical fiber according to claim 1 or 2, wherein the thread portion is impregnated with carbon and / or coated.

ねじ部外周に炭素繊維強化炭素複合材料製の補強部材が設けられていることを特徴とする請求項１ないし３のいずれか１に記載の光ファイバ製造用支持体。The optical fiber manufacturing support according to any one of claims 1 to 3, wherein a reinforcing member made of a carbon fiber reinforced carbon composite material is provided on the outer periphery of the screw portion.