JP4208226B2

JP4208226B2 - Tube fitting

Info

Publication number: JP4208226B2
Application number: JP2002069973A
Authority: JP
Inventors: 正英高橋; 清晶田中
Original assignee: Nichias Corp
Current assignee: Nichias Corp
Priority date: 2002-03-14
Filing date: 2002-03-14
Publication date: 2009-01-14
Anticipated expiration: 2022-03-14
Also published as: JP2003269673A

Description

【０００１】
【発明の属する技術分野】
本発明は、該継手本体の突出部にチューブの拡径部を嵌め、その状態で継手本体にナットをねじ込み締め付けることで、チューブの引抜抵抗を増すと共に突出部にチューブを密着させるチューブ継手に関する。
【０００２】
【従来の技術】
従来のチューブ継手ａは、図６に示すように、継手本体ｂの雄ネジ部ｃから縮径状態で延出した突出部ｄにチューブｅの拡径部ｆを嵌め、この状態で雄ネジ部ｃと雌ねじ部ｇとの協働により継手本体ｂにナットｈを締め込んで、ナットｈの押圧部ｉのエッジｊにより、チューブｅを継手本体ｂの突出部ｄにおける先端のテーパ部ｋに押しつけて、チューブｅの引抜抵抗を増すと共にテーパ部ｋにチューブｅを密着させるものである。このチューブ継手ａの材質がフッ素樹脂である場合、金属と比較して強度が低いからナットｈの締め込みにより、継手本体ｂに応力がかかり変形する。従って、長期の使用や振動により継手本体ｂの変形の度合が一層大きくなり遂には液漏れを起こすことから、適切なナットｈの増し締めを必要とした。更に、高温での使用、特にヒートサイクルでの使用は液漏れを起こす頻度が上昇するため、増し締めを頻繁に行い対処する必要がある。この頻繁の増し締めにより、継手本体ｂの変形はますます顕著となり、遂にはチューブ継手ａの寿命を縮めることになる。加えて、チューブ継手ａの高温での使用の場合、チューブｅの継手本体ｂやナットｈに対する引っかかりが少なく引抜抵抗が低いため、チューブ継手ａからチューブｅが抜ける可能性があり、安全性の観点から低圧力の流体での使用に限定されるという問題があった。
【０００３】
上記チューブ継手ａの変形による液漏れ及びそれを防止するためのナットｈの増し締め対策を施したものとして、実開平３−６１８８号公報がある。この公報例のチューブ継手ａ１は、図７に示すように、外周面に環状溝ｌ及び端部をテーパ部ｋとしたチューブ取付部ｍを備えた継手本体ｂ１と、チューブ取付部ｍに嵌めたチューブｅの周面部を没入させるように嵌合した割り溝付きで断面がほぼ台形のリングｎと、この台形のリングｎをチューブｅを介して環状溝ｌ内に没入させる傾斜内壁ｏ及びテーパ部ｋにチューブｅを圧接させる傾斜内面ｐを有するナットｈ１と、を具備している。そして、台形のリングｎによりチューブｅの周面部を環状溝ｌ内に没入させ、更にナットｈ１の傾斜内面ｐにより、チューブｅを継手本体ｂ１のテーパ部ｋに圧接させることで、液漏れや頻繁なナットｈ１の増し締めを無くし、更にチューブ継手ａ１からチューブｅが抜けないようにしている。
【０００４】
【発明が解決しようとする課題】
しかしながら、上記公報例のチューブ継手ａ１では、台形のリングｎに突起が無くナットｈ１の傾斜内壁ｏでチューブｅの周面部を環状溝ｌ内に没入させようとするため、チューブｅが十分変形せず、環状溝ｌ内に没入させ難い。また、ナットｈ１の傾斜内面ｐにより、チューブｅを継手本体ｂ１のテーパ部ｋに圧接させるため、押圧力が不十分である。これらの結果、公報例のチューブ継手ａ１は、引抜抵抗が不十分であり、且つシール性も不十分となって、長期の使用や振動がある場合はチューブ継手ａ１部分から液漏れを起こす虞があり、特に振動がある場合は適切なナットｈ１の増し締めを行う必要性は依然としてある。また、高温での使用やヒートサイクルでのチューブ継手ａ１の使用は、液漏れを起こす虞が上昇し、ナットｈ１の増し締めを十分行う必要があり、更に、高温高圧の流体でのチューブ継手としては、安全性の面で少し使い難いという問題があった。
【０００５】
従って、本発明の目的は、長期間の使用、振動が生じる状況下での使用、高温やヒートサイクルでの使用、高温高圧での使用等過酷な条件での使用を可能とする、シール性や引抜抵抗に優れるチューブ継手を提供することにある。
【０００６】
【課題を解決するための手段】
かかる状況において、本発明者らは、鋭意検討を行った結果、継手本体の雄ネジ部から縮径状態で延出した突出部の外周面に環状溝を設け、この突出部に嵌めたチューブの拡径部上にはめ輪を挿着し、その状態の継手本体にナットをねじ込み締め付け、ナットに設けた傾斜部によりはめ輪を環状溝内に変形させてチューブの引抜抵抗を増し、ナットに設けた押圧部の突部によりチューブを突出部の先端部に密着させれば、上記引抜抵抗の増加と相俟ってチューブのシール性が大きく増すことを見出し、本発明を完成するに至った。
【０００７】
すなわち、本発明の請求項１に記載のチューブ継手は、雄ネジ部から縮径状態で延出した突出部の外周面に環状溝を設けた継手本体と、該継手本体の突出部に嵌めたチューブの拡径部上に挿着するはめ輪と、該はめ輪を挿着した状態の継手本体にねじ込み自在であり、前記はめ輪とチューブを前記環状溝内に変形、縮径させる傾斜部と前記突出部の先端部にチューブを密着させる突部のある押圧部とを、雌ねじ部に続く内周面に順次設けたナットとからなり、該ナットを前記継手本体にねじ込むことで、チューブの引抜抵抗を増すと共に前記突出部にチューブを密着させることを特徴とする。
【０００８】
請求項２に記載の発明は、前記はめ輪の内周面に、その先端側からチューブとの引抜抵抗を増す突起及び前記はめ輪の変形性を高めるリング状溝を、順次設けたことを特徴とする。
【０００９】
請求項３に記載の発明は、前記はめ輪に該はめ輪の軸方向に割り溝を設けて、前記はめ輪の縮径性を高めることを特徴とする。
【００１０】
請求項４に記載の発明は、前記継手本体の突出部における先端と前記環状溝との間にテーパ部を形成し、該テーパ部とチューブとの密着性を高めることを特徴とする。
【００１１】
請求項５に記載の発明は、前記ナットの押圧部上にリング状のグリッパーを装着し、該グリッパーはチューブを前記突出部の先端部に密着させるグリッパー突部を有し、且つチューブより硬度が高く、前記ナットより弾性係数の大きい材質から構成していることを特徴とする。
【００１２】
【発明の実施の形態】
次に、本発明の実施の形態におけるチューブ継手を図１〜図４に基づいて詳述する。図１は本発明の実施の形態におけるチューブ継手を示す断面図、図２は本発明の実施の形態のチューブ継手によるチューブの接続状態を示す断面図である。両図において、チューブ継手１は、雄ネジ部２から縮径状態で延出した突出部３の外周面に環状溝４を設けた継手本体５と、この継手本体５の突出部３に嵌めたチューブ６の拡径部６ａ上に挿着するはめ輪７と、このはめ輪７を挿着した状態の継手本体５にねじ込み自在であり、はめ輪７を環状溝４内に変形させる傾斜部８と突出部３の先端部９にチューブ６を密着させる突部１０のある押圧部１１とを雌ねじ部１２に続く内周面に順次設けたナット１３とからなり、該ナット１３を継手本体５にねじ込み締め付けることで、チューブ６の引抜抵抗を増すと共に突出部３にチューブ６を密着させるものである。押圧部１１は、径方向に還状の面を有するもので、ナット１３の内側の底面に相当する。なお、チューブ継手１は、チューブ６をつなぐもの全てを含み、具体的にはエルボ、チーズ、レジューサ、コネクタ、ユニオン等の種類の継手である。
【００１３】
前記継手本体５は、既に述べた雄ネジ部２から延出した突出部３があり、その反対側に大径部２０がある。この大径部２０は、上述の種類の継手によりその形状が異なる。いずれにしても、継手本体５の軸方向中心にチューブ６の内径とほぼ同径の貫通孔２１があるが、行き止まりであってもよい。また、雄ネジ部２と突出部３との径違いにより生じた境界壁面にはチューブ６の拡径部６ａを差し込めるリング穴２２がある。また、継手本体５の突出部３における先端と前記環状溝４との間、すなわち、前記先端部９にテーパ部２３、場合によりこれに続く円周部２４を形成して、テーパ部２３及び円周部２４とチューブ６との密着性を高めている。
【００１４】
前記はめ輪７の構造を図３及び図４を参照して説明する。図３ははめ輪７の一部を切り欠いた縦断面図であり、図４ははめ輪７の端から見た図である。両図に示すように、はめ輪７はリング状をなし、その内周面に先端側からチューブ６との引抜抵抗を増す突起３０及びはめ輪７の変形性を高めるリング状溝３１を順次設け、その軸方向に割り溝３２を有する。突起３０は、チューブ６との引抜抵抗を増すためのものであり、その突起角度ｘは６０度≦ｘ≦１２０度の範囲、好ましくは９０度程度である。該突起角度が、鋭角過ぎると突起３０の強度が弱くなり、突起３０が変形しチューブ６への食い込みが低減する虞があり、鈍角過ぎるとチューブ６への食い込みが低減して引抜抵抗を増すことができない。また、リング状溝３１は、その軸方向の断面形状が円弧状であるから、その部分の厚みが薄くなり応力を集中し易く、ナット１３の傾斜部８によりはめ輪７を継手本体５の環状溝４内に座屈変形、すなわち、はめ輪７自体を縮径させ、それに伴いチューブ６も環状溝４内に押し込むことができる。更に、割り溝３２は、リング状溝３１と同様に、はめ輪７自体の縮径を容易にするものである。
【００１５】
前記ナット１３は、前記雌ねじ部１２により継手本体５と螺合可能となり、その螺合状態でナット１３の前記傾斜部８と継手本体５の雄ネジ部２との間が前記はめ輪７の収納部となり、更に、ナット１３の軸方向中心にチューブ６の外径とほぼ同径の貫通孔３３がある。そして、このナット１３の押圧部１１に設けた突部１０は、チューブ６との引抜抵抗を増すためのものであり、その突部角度ｙは、概ね６０度≦ｙ≦９０度の範囲である。該突部角度ｙが鋭角過ぎると突部１０の強度が弱くなり、突部１０が変形しチューブ６への食い込みが低減する虞があり、鈍角過ぎるとチューブ６への食い込みが低減され引抜抵抗を増すことができない。
【００１６】
また、ナット１３の押圧部１１に設けた突部１０の代わりに、押圧部１１上にリング状のグリッパー３４を装着してもよい。このグリッパー３４は、図５に示すように、チューブ６を突出部３の先端部９に密着させる突部３５を有し、且つチューブ６より硬度が高くナット１３より弾性係数の大きい材質から構成したものである。このグリッパー３４の働きは、押圧部１１と同様にチューブ６との引抜抵抗を増すためのものであり、グリッパー突部３５はその突部角度ｚが概ね６０度≦ｚ≦９０度の範囲である。該突部角度ｚが、鋭角過ぎるとチューブ６に食い込み過ぎて破損させる虞があり、また、グリッパー突部３５の強度が弱くなり突部が変形しチューブ６への食い込みが低減する。一方、鈍角過ぎるとチューブ６への食い込みが低減して引抜抵抗を増すことができない。また、グリッパー３４自体がナット１３の端部３６における内径を拡げようとする方向の力（グリッパー３４の径方向に作用する力）に抵抗し、しかも、グリッパー３４はナット１３より弾性係数の大きい材質であるから、特に引抜抵抗を増すことができる。
【００１７】
チューブ継手１の継手本体５、ナット１３、はめ輪７、チューブ６の材質は、プラスチックであれば、特に限定がないが、耐薬品性、耐熱性を必要とする用途である場合は、いずれもふっ素樹脂系のものが好適である。具体的には、テトラフルオロエチレン・パーフルオロアルキルビニルエーテル共重合体（ＰＦＡ）、ポリテトラフルオロエチレン（ＰＴＦＥ）、テトラフルオロエチレン・ヘキサフロオロプロピレン共重合体（ＦＥＰ）、テトラフルオロエチレン・エチレン共重合体（ＥＴＦＥ）等が挙げられる。また、グリッパーの材質としては、チューブ６の材質より硬度が高くナット１３より弾性係数の大きい材質であれば、特に制限されないが、チューブ６等の材質がふっ素樹脂系のものが採用されている場合は、ポリエーテルエーテルケトン（ＰＥＥＫ）、ポリエーテルスルホン（ＰＥＳ）、ポリフェニレンスルファイド（ＰＰＳ）、ポリイミド（ＰＩ）、ポリアリレート（ＰＡＲ）、液晶ポリマー（ＬＣＰ）等の硬く且つ強度のあるスーパーエンジニアリングプラスチックが好適である。
【００１８】
次に、上記構成からなるチューブ継手１の使用方法について説明する。まず、使用目的に沿うチューブ６並びにこれに沿うチューブ継手１を選択する。選択したチューブ６に予めナット１３、はめ輪７を通しておき、次いでチューブ６の一端に、継手本体５のリング穴２２に差し込めるように拡径処理を施す。その際、グリッパー３４が有る場合は予め押圧部１１上に装着しておく。そして、継手本体５のリング穴２２にチューブ６の拡径部６ａを嵌め、その拡径部６ａ上にはめ輪７を割り溝３２を利用して嵌める。次いで、継手本体５にナット１３をねじ込んで行く。継手本体５にナット１３を更にねじ込み締め付けて行くと、図２に示すように、ナット１３の傾斜部８によりはめ輪７が雄ネジ部２側に押圧され、応力がリング状溝３１により薄くなった部分に集中し、継手本体５の環状溝４内に座屈変形するため、それと共にチューブ６にはめ輪７の突起３０が食い込み、チューブ６も環状溝４内に押し込まれることになる。同時に、ナット１３の押圧部１１の突部１０あるいはグリッパー３４の突部３５によりチューブ６に食い込み且つ継手本体５の先端部９にチューブ６を密着させる。すなわち、先端部９がテーパ部２３のみで形成している時はテーパ部２３に、テーパ部２３及び円周部２４で形成しているときは双方に、チューブ６を密着させる。
【００１９】
本発明において、継手本体５にナット１３をねじ込むことにより形成されたチューブ継手は、(１)はめ輪７によりチューブ６が変形、縮径することにより生じる引抜抵抗Ａ、(２)はめ輪７の突起３０がチューブ６を押圧し食い込むことにより生じる引抜抵抗Ｂ、(３) ナット１３の押圧部１１の突部１０あるいはグリッパー３４の突部３５がチューブ６を押圧し食い込むことにより生じる引抜抵抗Ｃ、及び(４)ナット１３より弾性係数の大きい材質のグリッパー３４自体による径方向に作用する力に抗する引抜抵抗Ｄがそれぞれ作用することにより、極めて高いシール性と引抜抵抗を発現する。すなわち、上記(３)のナット１３の突部１０あるいはグリッパー３４の突部３５がチューブ６を押圧し、同時に(２)のはめ輪７の突起３０がチューブ６を押圧することにより、チューブ６が継手本体５のテーパ部２３並びに円周部２４に強く密着し、高いシール性を発現する。
【００２０】
【実施例】
次に、実施例を挙げて本発明を更に具体的に説明するが、これは単に例示であって、本発明を制限するものではない。
（実施例１）
チューブ継手の構造は、図１に示す形状とし、継手本体、ナット、はめ輪、及びチューブの材質はいずれもふっ素樹脂ＰＦＡとし、グリッパーはＰＥＥＫとした。両材質の引張弾性率（２３℃）は、ＰＦＡが４５０Ｍｐａ、ＰＥＥＫが３５００Ｍｐａであった。継手本体の突出部の内径は１５．９mm、外径２１．５mm、テーパ部２３の傾斜角は３０度、環状溝の最大深さは１．１mm、幅６mmとした。はめ輪の内径２４．２mm、外径２７．６mm、突起角度ｘは９０度、リング状溝の最大深さは０．７mm、幅４mmとした。グリッパーの内径１９．１mm、外径２４．０mm、突起角度ｚは７０度、チューブの内径は１５．９mm、外径１９．１mmとした。
そして、チューブの一端を冶具にて拡径部とし、その拡径部を継手本体の突出部に嵌めナットを締め込み、チューブに継いだチューブ継手の試験サンプルを作製した。この試験サンプルに対して、以下の通りの（１）２００℃ヒートサイクル後のシール試験、（２）引抜試験、（３）振動後のシール試験を行った。その結果を表１〜表３に示した。
【００２１】
（１）２００℃ヒートサイクル後のシール試験
ＳＥＭＩＦ７−９２に準拠し、試験サンプルを２００℃で２４時間加熱し続けた後、２５℃に自然冷却して水中に入れ、０．２MPaから１．６MPaまでの間０．２MPaづつ昇圧し各圧力で３０分間保持し、その間の窒素ガスの漏れを測定して、それを１サイクルとする。このサイクルを２０回繰り返す。
【００２２】
（２）引抜試験
引張試験機に試験サンプルを接続し、２５℃、１００℃、２００℃の各温度における引抜強度とチューブの伸びとを測定する。なお、１００℃、２００℃の各温度では３０分間加熱し続けた後、引抜強度とチューブの伸びとを測定する。
【００２３】
（３）振動後のシール試験
試験サンプルはチューブ継手に長さ２５０mmのチューブを継ぎ、チューブ継手の雄ネジ部側を固定し、チューブ先端の振幅を１００mmとし振動速度２サイクル／秒で振動させ、５万サイクル毎に５０万サイクルまで、試験サンプルを上記（１）のシール試験と同じようにして、窒素ガスの漏れを測定する。
【００２４】
実施例２
試験サンプルにグリッパーを装着しないで、更にナットの押圧部突部角度を７７度とした以外は、実施例１と同様の試験サンプルを作製し、その試験サンプルにて、上記（１）２００℃ヒートサイクル後のシール試験、（２）引抜試験、及び（３）振動後のシール試験を行った。その結果を表１〜表３に示した。
【００２５】
（比較例１）
チューブ継手の構造は、図６に示す形状とした以外、実施例１と同様の試験サンプルを作製し、該試験サンプルにて、上記（１）２００℃ヒートサイクル後のシール試験、（２）引抜試験及び（３）振動後のシール試験を行った。その結果を表１〜表３に示した。
【００２６】
（比較例２）
チューブ継手の構造は、図７に示す形状とし、継手本体、ナット、リング及びチューブの材質はいずれもふっ素樹脂ＰＦＡとした。継手本体の突出部の内径は１５．９mm、外径２１．５mm、テーパ部の傾斜角は３０度、環状溝の最大深さは１．１mm、幅６mmとした。また、リングの内径２４．２mm、短外径２９．０mm、長外径３４．２mm、幅３．０mm、テーパ角度３０度、割り幅６．９mmとした。ナットの傾斜内壁oの角度３０度であり、チューブは実施例１と同じである。そして、チューブの一端を冶具にて拡径部とし、その拡径部を継手本体の突出部に嵌めナットを締め込み、チューブに継いだチューブ継手の試験サンプルを作製した。この試験サンプルに対して、実施例１と同様に、（１）２００℃ヒートサイクル後のシール試験、（２）引抜試験及び（３）振動後のシール試験を行ったその結果を表１〜表３に示した。なお、表１は（１）２００℃ヒートサイクル後のシール試験の結果であり、表２は引抜試験の結果であり、表３は振動後のシール試験の結果である。表１及び表３中、「０」は３０分後間窒素ガス漏れ無しを示し、例えば「１／３．０分」の表示は、３．０分間で窒素ガスの気泡が１個浮上したことを示す。
【００２７】
【表１】

【００２８】
【表２】

【００２９】
【表３】

【００３０】
表１によれば、本発明の条件に当てはまる実施例１及び実施例２は、２００℃ヒートサイクル後のシール試験において、比較例１及び比較例２よりもはるかに良い結果が得られた。また、表２によれば、本発明の条件に当てはまる実施例１及び実施例２は、引抜試験においても、比較例１及び比較例２よりも３倍程良い結果が得られた。更に、表３によれば、本発明の条件に当てはまる実施例１及び実施例２は振動後のシール試験においても、比較例１及び比較例２よりもはるかに良い結果が得られた。
【００３１】
以上、本発明の実施形態を説明したが、具体的な構成はこれに限定されず、本発明の要旨を逸脱しない範囲での変更、追加は本発明の範囲内である。
【００３２】
【発明の効果】
以上詳述したように、請求項１の発明のチューブ継手によれば、継手本体にナットをねじ込み締め付けて行くと、傾斜部によりはめ輪が雄ネジ部２側に押圧され、応力がリング状溝により薄くなった部分に集中し、環状溝内に座屈変形し、それと共にチューブにはめ輪の突起が食い込みチューブも環状溝内に押し込まれ、同時に、ナットの突部がチューブに食い込み且つ継手本体の先端部にチューブを密着させる。従って、劇的にチューブの引抜抵抗が増すと共にシール性も増すから、長期使用や振動時使用、高温やヒートサイクルでの使用、高温高圧での使用を可能とする効果がある。
【００３３】
請求項２の発明によれば、はめ輪の突起がチューブに食い込み引抜抵抗を増し、リング状溝によりはめ輪が環状溝内に座屈変形し易くなる。従って、上記効果が一層顕著になる。
【００３４】
請求項３の発明によれば、割り溝によりはめ輪の縮径性を高め、はめ輪が環状溝内に座屈変形し易くなる。従って、上記効果に加えて、引抜抵抗が特に顕著になる。
【００３５】
請求項４の発明によれば、継手本体の突出部におけるテーパ部により、チューブとの密着性が高まる。従って、上記効果に加え、シール性が特に顕著になる。
【００３６】
請求項５の発明によれば、グリッパーの突部がチューブに食い込み且つ継手本体の突出部の先端部に密着させ、ナットの端部の内径を拡げる方向の力をグリッパー自体の強度により防ぐ。従って、上記効果に加え、引抜抵抗及びシール性が特に顕著になる。
【図面の簡単な説明】
【図１】本発明の実施の形態であるチューブ継手を示す断面図である。
【図２】本発明の実施の形態であるチューブ継手によるチューブの接続状態を示す断面図である。
【図３】本発明の実施の形態であるチューブ継手の構成要素のはめ輪の一部を切り欠いた縦断面図である。
【図４】本発明の実施の形態であるチューブ継手の構成要素のはめ輪の端から見た図である。
【図５】本発明の実施の形態であるチューブ継手の構成要素のグリッパーの縦断面図である。
【図６】従来例を示す縦断面図である。
【図７】従来例を示す縦断面図である。
【符号の説明】
１、ａ、ａ１チューブ継手
２、ｃ雄ネジ部
３、ｄ突出部
４、ｌ環状溝
５、ｂ継手本体
６、ｅチューブ
６ａ、ｆ拡径部
７はめ輪
８傾斜部
９先端部
１０、３５突部
１１、ｉ押圧部
１２、ｇ雌ねじ部
１３、ｈ、ｈ１ナット
２０大径部
２１、３３貫通孔
２２リング穴
２３、ｋテーパ部
２４円周部
３０突起
３１リング状溝
３２割り溝
３４グリッパー
３５グリッパー突部
３６端部
ｊエッジ
ｍチューブ取付部
ｎリング
ｏ傾斜内壁
ｐ傾斜内面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tube joint in which a diameter-expanded portion of a tube is fitted to a protruding portion of the joint main body, and a nut is screwed into the joint main body and tightened in that state, thereby increasing the pull-out resistance of the tube and bringing the tube into close contact with the protruding portion.
[0002]
[Prior art]
As shown in FIG. 6, in the conventional tube joint a, the expanded portion f of the tube e is fitted into the protruding portion d that extends in a reduced diameter state from the male thread portion c of the joint body b, and in this state, the male thread portion The nut h is fastened to the joint body b by the cooperation of c and the female thread part g, and the tube e is pressed against the tapered part k at the tip of the protruding part d of the joint body b by the edge j of the pressing part i of the nut h. Thus, the pull-out resistance of the tube e is increased and the tube e is brought into close contact with the tapered portion k. When the tube joint a is made of a fluororesin, the joint body b is stressed and deformed by tightening the nut h because the strength is lower than that of metal. Accordingly, since the degree of deformation of the joint body b is further increased due to long-term use and vibration, liquid leakage eventually occurs, so that it is necessary to retighten an appropriate nut h. Furthermore, use at high temperatures, especially use in a heat cycle, increases the frequency of liquid leakage, so it is necessary to deal with frequent tightening. Due to this frequent tightening, the deformation of the joint body b becomes more and more remarkable, and eventually the life of the tube joint a is shortened. In addition, when the tube joint a is used at a high temperature, the tube e is less likely to get caught on the joint body b or the nut h, and the pull-out resistance is low. Therefore, there is a problem that it is limited to use with a low-pressure fluid.
[0003]
Japanese Utility Model Laid-Open No. 3-6188 discloses a measure against liquid leakage due to deformation of the tube joint a and a tightening of the nut h for preventing the leakage. As shown in FIG. 7, the tube joint a1 of this publication is fitted into a tube body m1 and a tube body m1 provided with a tube mounting portion m having an annular groove l and a tapered portion k on the outer peripheral surface. A ring n having a substantially trapezoidal cross-section with a split groove fitted so as to immerse the peripheral surface portion of the tube e, an inclined inner wall o and a taper portion for immersing the trapezoidal ring n into the annular groove l via the tube e a nut h1 having an inclined inner surface p that presses the tube e against k. Then, the trapezoidal ring n immerses the peripheral surface portion of the tube e into the annular groove l, and further presses the tube e against the tapered portion k of the joint body b1 by the inclined inner surface p of the nut h1, thereby causing liquid leakage and frequent occurrence. Further tightening of the nut h1 is eliminated, and the tube e is prevented from coming off from the tube joint a1.
[0004]
[Problems to be solved by the invention]
However, in the tube joint a1 in the above publication example, since the trapezoidal ring n has no protrusion and the inclined inner wall o of the nut h1 tries to immerse the peripheral surface portion of the tube e into the annular groove l, the tube e is sufficiently deformed. Therefore, it is difficult to be immersed in the annular groove l. Further, since the tube e is pressed against the tapered portion k of the joint body b1 by the inclined inner surface p of the nut h1, the pressing force is insufficient. As a result, the tube joint a1 in the publication example has insufficient pull-out resistance and insufficient sealability, and there is a risk of liquid leakage from the tube joint a1 portion when there is long-term use or vibration. There is still a need to retighten the appropriate nut h1, particularly when there is vibration. In addition, use of the tube joint a1 at high temperatures or heat cycles raises the possibility of liquid leakage, and it is necessary to fully tighten the nut h1. Furthermore, as a tube joint with high-temperature and high-pressure fluid However, there was a problem that it was a little difficult to use in terms of safety.
[0005]
Therefore, the purpose of the present invention is to enable use under severe conditions such as long-term use, use under conditions where vibration occurs, use at high temperatures and heat cycles, use at high temperatures and high pressures, An object of the present invention is to provide a tube joint excellent in pulling resistance.
[0006]
[Means for Solving the Problems]
In such a situation, as a result of intensive studies, the present inventors have provided an annular groove on the outer peripheral surface of the projecting portion extending in a reduced diameter from the male thread portion of the joint body, and the tube fitted in the projecting portion Insert the ferrule on the expanded diameter part, screw the nut into the joint body in that state, tighten it, and deform the ferrule into the annular groove by the inclined part provided on the nut to increase the pull-out resistance of the tube, and install it on the nut. It has been found that if the tube is brought into close contact with the tip of the protruding portion by the protruding portion of the pressing portion, the sealing performance of the tube is greatly increased in combination with the increase in the pulling resistance, and the present invention has been completed.
[0007]
That is, the tube joint according to claim 1 of the present invention is fitted to the joint body provided with an annular groove on the outer peripheral surface of the projecting part extending in a reduced diameter state from the male screw part, and the projecting part of the joint body. A ferrule to be inserted on the diameter-expanded portion of the tube, and an inclined portion which can be screwed into the joint body in a state in which the ferrule is inserted, and which deforms and reduces the diameter of the ferrule and the tube into the annular groove; A pressing portion having a protrusion for tightly attaching the tube to the tip of the protruding portion, and a nut sequentially provided on the inner peripheral surface following the female screw portion, and screwing the nut into the joint body, thereby pulling out the tube While increasing resistance, the tube is brought into close contact with the protruding portion.
[0008]
The invention according to claim 2 is characterized in that a protrusion that increases the pulling resistance with the tube and a ring-shaped groove that improves the deformability of the ferrule are sequentially provided on the inner peripheral surface of the ferrule. And
[0009]
The invention described in claim 3 is characterized in that the ferrule is provided with a split groove in the axial direction of the ferrule so as to improve the diameter-reducing property of the ferrule.
[0010]
The invention according to claim 4 is characterized in that a taper portion is formed between the tip of the projecting portion of the joint body and the annular groove to improve the adhesion between the taper portion and the tube.
[0011]
According to a fifth aspect of the present invention, a ring-shaped gripper is mounted on the pressing portion of the nut, the gripper has a gripper protrusion that makes the tube closely contact the tip of the protrusion, and has a hardness higher than that of the tube. It is made of a material having a higher elastic coefficient than that of the nut.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, the tube joint in the embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 is a cross-sectional view showing a tube joint in the embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a connection state of tubes by the tube joint of the embodiment of the present invention. In both figures, the tube joint 1 is fitted into the joint body 5 in which the annular groove 4 is provided on the outer peripheral surface of the projecting portion 3 extending in a reduced diameter state from the male screw portion 2 and the projecting portion 3 of the joint body 5. A ferrule 7 to be inserted on the enlarged diameter portion 6 a of the tube 6, and an inclined portion 8 that can be screwed into the joint body 5 in a state in which the ferrule 7 is inserted, and deforms the ferrule 7 into the annular groove 4. And a pressing portion 11 having a protruding portion 10 for bringing the tube 6 into close contact with the distal end portion 9 of the protruding portion 3, and a nut 13 sequentially provided on the inner peripheral surface following the female screw portion 12. By screwing and tightening, the pulling resistance of the tube 6 is increased and the tube 6 is brought into close contact with the protruding portion 3. The pressing portion 11 has a return surface in the radial direction, and corresponds to the bottom surface inside the nut 13. In addition, the tube coupling 1 includes all those that connect the tubes 6, and specifically, is a type of coupling such as elbow, cheese, reducer, connector, and union.
[0013]
The joint body 5 has a protruding portion 3 extending from the male screw portion 2 already described, and a large diameter portion 20 on the opposite side. The shape of the large-diameter portion 20 differs depending on the type of joint described above. In any case, although there is a through hole 21 having the same diameter as the inner diameter of the tube 6 at the axial center of the joint body 5, it may be a dead end. Further, the boundary wall surface generated by the difference in diameter between the male screw portion 2 and the protruding portion 3 has a ring hole 22 into which the enlarged diameter portion 6a of the tube 6 can be inserted. In addition, a tapered portion 23 and, optionally, a circumferential portion 24 following the tapered portion 23 and the circular portion 4 are formed between the distal end of the protruding portion 3 of the joint body 5 and the annular groove 4, that is, the distal end portion 9. The adhesion between the peripheral portion 24 and the tube 6 is enhanced.
[0014]
The structure of the ferrule 7 will be described with reference to FIGS. FIG. 3 is a longitudinal sectional view with a part of the ferrule 7 cut away, and FIG. 4 is a view seen from the end of the ferrule 7. As shown in both figures, the ferrule 7 has a ring shape, and a protrusion 30 for increasing the pulling resistance with the tube 6 from the tip side and a ring-shaped groove 31 for improving the deformability of the ferrule 7 are sequentially provided on the inner peripheral surface thereof. , And has a split groove 32 in its axial direction. The protrusion 30 is for increasing the pulling resistance with the tube 6, and the protrusion angle x is in the range of 60 degrees ≦ x ≦ 120 degrees, preferably about 90 degrees. If the projection angle is too acute, the strength of the projection 30 is weakened, and the projection 30 may be deformed and the biting into the tube 6 may be reduced. If the projection angle is too blunt, the biting into the tube 6 is reduced and the pulling resistance is increased. I can't. Further, since the axial shape of the ring-shaped groove 31 is an arc shape, the thickness of the ring-shaped groove 31 is thin and the stress is easily concentrated. Buckling deformation into the groove 4, that is, the diameter of the ferrule 7 itself can be reduced, and the tube 6 can be pushed into the annular groove 4 accordingly. Furthermore, like the ring-shaped groove 31, the split groove 32 facilitates the diameter reduction of the ferrule 7 itself.
[0015]
The nut 13 can be screwed into the joint main body 5 by the female threaded portion 12, and in the screwed state, the fitting ring 7 is accommodated between the inclined portion 8 of the nut 13 and the male threaded portion 2 of the joint main body 5. Furthermore, a through-hole 33 having the same diameter as the outer diameter of the tube 6 is provided at the axial center of the nut 13. And the protrusion 10 provided in the press part 11 of this nut 13 is for increasing pulling resistance with the tube 6, The protrusion angle y is the range of 60 degrees <= y <= 90 degree in general. . If the projection angle y is too acute, the strength of the projection 10 is weakened, and the projection 10 may be deformed and the biting into the tube 6 may be reduced. If the projection angle y is too blunt, the biting into the tube 6 is reduced and the pulling resistance is reduced. It cannot be increased.
[0016]
Further, instead of the protrusion 10 provided on the pressing part 11 of the nut 13, a ring-shaped gripper 34 may be mounted on the pressing part 11. As shown in FIG. 5, the gripper 34 has a protrusion 35 that causes the tube 6 to be in close contact with the tip 9 of the protrusion 3, and is made of a material that is harder than the tube 6 and has a larger elastic coefficient than the nut 13. Is. The function of the gripper 34 is to increase the pulling resistance with the tube 6 similarly to the pressing portion 11, and the gripper projection 35 has a projection angle z in a range of approximately 60 degrees ≦ z ≦ 90 degrees. . If the projection angle z is too acute, the tube 6 may bite into the tube 6 and be damaged, and the gripper projection 35 is weakened and the projection is deformed to reduce biting into the tube 6. On the other hand, if the angle is too obtuse, the biting into the tube 6 is reduced and the pulling resistance cannot be increased. Further, the gripper 34 itself resists a force in a direction to expand the inner diameter of the end portion 36 of the nut 13 (a force acting in the radial direction of the gripper 34), and the gripper 34 is a material having a larger elastic coefficient than the nut 13. Therefore, the drawing resistance can be particularly increased.
[0017]
The material of the joint body 5, the nut 13, the ferrule 7, and the tube 6 of the tube joint 1 is not particularly limited as long as it is plastic, but in any case that requires chemical resistance and heat resistance, A fluororesin type is preferred. Specifically, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / ethylene copolymer Examples include coalescence (ETFE). The material of the gripper is not particularly limited as long as the material is harder than the material of the tube 6 and has a larger elastic coefficient than the nut 13. However, the material of the tube 6 or the like is a fluororesin material. Hard and strong super engineering plastics such as polyether ether ketone (PEEK), polyether sulfone (PES), polyphenylene sulfide (PPS), polyimide (PI), polyarylate (PAR), liquid crystal polymer (LCP) Is preferred.
[0018]
Next, the usage method of the tube coupling 1 which consists of the said structure is demonstrated. First, the tube 6 along the purpose of use and the tube joint 1 along the same are selected. The selected tube 6 is passed through the nut 13 and the ferrule 7 in advance, and then one end of the tube 6 is subjected to diameter expansion processing so that it can be inserted into the ring hole 22 of the joint body 5. At that time, if the gripper 34 is provided, it is mounted on the pressing portion 11 in advance. Then, the enlarged diameter portion 6 a of the tube 6 is fitted into the ring hole 22 of the joint body 5, and the ferrule 7 is fitted on the enlarged diameter portion 6 a using the split groove 32. Next, the nut 13 is screwed into the joint body 5. When the nut 13 is further screwed into the joint body 5 and tightened, as shown in FIG. 2, the fitting ring 7 is pressed to the male screw portion 2 side by the inclined portion 8 of the nut 13, and the stress is reduced by the ring-shaped groove 31. Therefore, the projection 30 of the snap ring 7 bites into the tube 6 and the tube 6 is also pushed into the annular groove 4. At the same time, the projection 6 of the pressing portion 11 of the nut 13 or the projection 35 of the gripper 34 bites into the tube 6, and the tube 6 is brought into close contact with the distal end portion 9 of the joint body 5. That is, the tube 6 is brought into close contact with the tapered portion 23 when the distal end portion 9 is formed only with the tapered portion 23, and both when the distal end portion 9 is formed with the tapered portion 23 and the circumferential portion 24.
[0019]
In the present invention, the tube joint formed by screwing the nut 13 into the joint body 5 is (1) the pull-out resistance A generated when the tube 6 is deformed and reduced in diameter by the ferrule 7, and (2) the ferrule 7 Pull-out resistance B generated when the protrusion 30 presses and bites the tube 6; (3) Pull-out resistance C generated when the protrusion 10 of the pressing portion 11 of the nut 13 or the protrusion 35 of the gripper 34 presses and bites the tube 6; And (4) The pulling resistance D that resists the force acting in the radial direction by the gripper 34 itself made of a material having a larger elastic coefficient than that of the nut 13 acts, thereby exhibiting extremely high sealing performance and pulling resistance. That is, the protrusion 10 of the nut 13 or the protrusion 35 of the gripper 34 in the above (3) presses the tube 6, and at the same time, the protrusion 30 of the snap ring 7 in (2) presses the tube 6. It strongly adheres to the tapered portion 23 and the circumferential portion 24 of the joint body 5 and exhibits high sealing performance.
[0020]
【Example】
EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.
Example 1
The structure of the tube joint was the shape shown in FIG. 1, the joint body, nut, snap ring, and tube were all made of fluororesin PFA, and the gripper was PEEK. The tensile modulus (23 ° C.) of both materials was 450 Mpa for PFA and 3500 Mpa for PEEK. The inner diameter of the protrusion of the joint body was 15.9 mm, the outer diameter was 21.5 mm, the inclination angle of the tapered portion 23 was 30 degrees, the maximum depth of the annular groove was 1.1 mm, and the width was 6 mm. The inner diameter of the ferrule was 24.2 mm, the outer diameter was 27.6 mm, the projection angle x was 90 degrees, the maximum depth of the ring-shaped groove was 0.7 mm, and the width was 4 mm. The inner diameter of the gripper was 19.1 mm, the outer diameter was 24.0 mm, the protrusion angle z was 70 degrees, the inner diameter of the tube was 15.9 mm, and the outer diameter was 19.1 mm.
And the one end of the tube was made into the enlarged diameter part with a jig, the enlarged diameter part was fitted in the protrusion part of the joint main body, the nut was tightened, and the test sample of the tube joint joined to the tube was produced. The test sample was subjected to the following (1) seal test after 200 ° C. heat cycle, (2) pull-out test, and (3) seal test after vibration. The results are shown in Tables 1 to 3.
[0021]
(1) Seal test after 200 ° C. heat cycle In accordance with SEMI F7-92, the test sample was continuously heated at 200 ° C. for 24 hours, then naturally cooled to 25 ° C. and placed in water. The pressure is increased by 0.2 MPa up to 6 MPa, held at each pressure for 30 minutes, and the leakage of nitrogen gas is measured during that time, which is defined as one cycle. This cycle is repeated 20 times.
[0022]
(2) Pull-out test A test sample is connected to a tensile tester, and the pull-out strength and tube elongation at temperatures of 25 ° C, 100 ° C, and 200 ° C are measured. In addition, after continuing heating for 30 minutes at each temperature of 100 degreeC and 200 degreeC, a drawing strength and the elongation of a tube are measured.
[0023]
(3) Seal test after vibration For the test sample, a tube with a length of 250 mm was connected to the tube joint, the male thread side of the tube joint was fixed, the tube tip amplitude was 100 mm, and the sample was vibrated at a vibration speed of 2 cycles / second. Nitrogen gas leakage is measured every 50,000 cycles up to 500,000 cycles in the same manner as the seal test of (1) above.
[0024]
Example 2
A test sample similar to that of Example 1 was prepared except that the gripper was not attached to the test sample and the pressing portion protrusion angle of the nut was changed to 77 degrees, and the test sample was heated at (1) 200 ° C. A seal test after the cycle, (2) a pull-out test, and (3) a seal test after vibration were performed. The results are shown in Tables 1 to 3.
[0025]
(Comparative Example 1)
The structure of the tube joint is the same as that of Example 1 except that the shape shown in FIG. 6 is used. Using the test sample, (1) Seal test after 200 ° C. heat cycle, (2) Pull-out Test and (3) Seal test after vibration were performed. The results are shown in Tables 1 to 3.
[0026]
(Comparative Example 2)
The structure of the tube joint was the shape shown in FIG. 7, and the material of the joint body, nut, ring and tube was all made of fluororesin PFA. The inner diameter of the protrusion of the joint body was 15.9 mm, the outer diameter was 21.5 mm, the inclination angle of the tapered portion was 30 degrees, the maximum depth of the annular groove was 1.1 mm, and the width was 6 mm. The inner diameter of the ring was 24.2 mm, the short outer diameter was 29.0 mm, the long outer diameter was 34.2 mm, the width was 3.0 mm, the taper angle was 30 degrees, and the split width was 6.9 mm. The angle of the inclined inner wall o of the nut is 30 degrees, and the tube is the same as in the first embodiment. And the one end of the tube was made into the enlarged diameter part with a jig, the enlarged diameter part was fitted in the protrusion part of the joint main body, the nut was tightened, and the test sample of the tube joint joined to the tube was produced. The results of (1) a seal test after 200 ° C. heat cycle, (2) a pull-out test, and (3) a seal test after vibration on the test sample are shown in Tables 1 to 1 as in Example 1. It was shown in 3. Table 1 shows the results of the seal test after (1) 200 ° C. heat cycle, Table 2 shows the results of the pull-out test, and Table 3 shows the results of the seal test after vibration. In Tables 1 and 3, “0” indicates no nitrogen gas leakage after 30 minutes. For example, “1 / 3.0 minutes” indicates that one bubble of nitrogen gas has floated in 3.0 minutes. Indicates.
[0027]
[Table 1]

[0028]
[Table 2]

[0029]
[Table 3]

[0030]
According to Table 1, Example 1 and Example 2 that meet the conditions of the present invention gave much better results than Comparative Example 1 and Comparative Example 2 in the seal test after 200 ° C. heat cycle. Moreover, according to Table 2, Example 1 and Example 2 applicable to the conditions of the present invention obtained results about three times better than Comparative Example 1 and Comparative Example 2 in the pull-out test. Furthermore, according to Table 3, the results of Examples 1 and 2 that satisfy the conditions of the present invention were much better than those of Comparative Examples 1 and 2 in the seal test after vibration.
[0031]
As mentioned above, although embodiment of this invention was described, a specific structure is not limited to this, The change and addition in the range which does not deviate from the summary of this invention are in the scope of this invention.
[0032]
【The invention's effect】
As described above in detail, according to the tube joint of the first aspect of the present invention, when the nut is screwed into the joint body and tightened, the fitting ring is pressed to the male screw portion 2 side by the inclined portion, and the stress is reduced to the ring-shaped groove. Concentrates on the thinner part, buckles and deforms in the annular groove, and at the same time, the projection of the snap ring bites into the tube and the tube is also pushed into the annular groove. At the same time, the protrusion of the nut bites into the tube and the joint body Adhere the tube to the tip of the tube. Therefore, since the pulling resistance of the tube is dramatically increased and the sealing property is also increased, there is an effect that enables long-term use, vibration use, use at high temperature and heat cycle, and use at high temperature and high pressure.
[0033]
According to the invention of claim 2, the projection of the ferrule bites into the tube to increase the pull-out resistance, and the ferrule is easily buckled into the annular groove by the ring-shaped groove. Therefore, the above effect becomes more remarkable.
[0034]
According to the invention of claim 3, the diameter reduction property of the fitting ring is enhanced by the split groove, and the fitting ring is easily buckled and deformed in the annular groove. Therefore, in addition to the above effect, the pulling resistance becomes particularly significant.
[0035]
According to invention of Claim 4, adhesiveness with a tube increases with the taper part in the protrusion part of a coupling main body. Therefore, in addition to the above effects, the sealing performance becomes particularly remarkable.
[0036]
According to the invention of claim 5, the protrusion of the gripper bites into the tube and is brought into close contact with the tip of the protrusion of the joint body, and the force in the direction of expanding the inner diameter of the end of the nut is prevented by the strength of the gripper itself. Therefore, in addition to the above effects, the drawing resistance and the sealing performance are particularly remarkable.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a tube joint according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a connection state of tubes by a tube joint according to an embodiment of the present invention.
FIG. 3 is a longitudinal sectional view in which a part of a snap ring of a component of a tube joint according to an embodiment of the present invention is cut away.
FIG. 4 is a view seen from the end of a ferrule of a component of the tube joint according to the embodiment of the present invention.
FIG. 5 is a longitudinal sectional view of a gripper as a component of a tube joint according to an embodiment of the present invention.
FIG. 6 is a longitudinal sectional view showing a conventional example.
FIG. 7 is a longitudinal sectional view showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, a, a1 Tube joint 2, c Male thread part 3, d Protrusion part 4, l Annular groove 5, b Joint main body 6, e Tube 6a, f Diameter expansion part 7 Fitting wheel 8 Inclination part 9

Tip part

10, 35 Projection 11, i Pressing part 12, g Female thread part 13, h, h1 Nut 20

Large diameter part

21, 33 Through hole 22 Ring hole 23, k Taper part 24 Circumferential part 30 Projection 31 Ring-shaped groove 32 Split groove 34 Gripper 35 Gripper protrusion 36 End j Edge m Tube mounting portion n Ring o Inclined inner wall p Inclined inner surface

Claims

A joint body provided with an annular groove on the outer peripheral surface of the projecting part extending in a reduced diameter from the male thread part, a ferrule to be inserted on the enlarged diameter part of the tube fitted to the projecting part of the joint body, The fitting body with the ferrule inserted therein can be screwed freely, and there is an inclined portion for deforming and reducing the diameter of the ferrule and the tube into the annular groove, and a protrusion for bringing the tube into close contact with the tip of the protruding portion. The pressing portion comprises a nut sequentially provided on the inner peripheral surface following the female screw portion, and by screwing the nut into the joint body, the pulling resistance of the tube is increased and the tube is brought into close contact with the protruding portion. Tube fitting.

2. The tube joint according to claim 1, wherein a projection that increases the pulling resistance with the tube from the tip end side and a ring-shaped groove that increases the deformability of the snap ring are sequentially provided on the inner peripheral surface of the snap ring. .

The tube joint according to claim 1 or 2, wherein a split groove is provided in the ferrule in the axial direction of the ferrule so as to enhance the diameter reduction of the ferrule.

The taper part is formed between the front-end | tip in the protrusion part of the said coupling main body, and the said annular groove, The adhesiveness of this taper part and a tube is improved, The any one of Claims 1-3 characterized by the above-mentioned. Tube fitting.

A ring-shaped gripper is mounted on the pressing portion of the nut, and the gripper has a gripper protrusion for tightly attaching the tube to the tip of the protrusion, and is harder than the tube and has a larger elastic coefficient than the nut. The tube joint according to any one of claims 1 to 4, wherein the tube joint is made of a material.