JP4456192B2

JP4456192B2 - Connection structure between metal pipe and mating parts

Info

Publication number: JP4456192B2
Application number: JP02931199A
Authority: JP
Inventors: 信夫加藤; 修遠藤; 啓明近藤
Original assignee: Usui Co Ltd
Current assignee: Usui Co Ltd
Priority date: 1999-02-05
Filing date: 1999-02-05
Publication date: 2010-04-28
Anticipated expiration: 2019-02-05
Also published as: JP2000227183A

Description

【０００１】
【発明の属する技術分野】
本発明は、一般に自動車あるいは各種機械、装置などに給油、給気の供給路などとして配設される比較的細径で、薄肉もしくは厚肉からなる金属管の管端部に形成された押圧座面を、端金具、継手、噴射ポンプや噴射ノズルなどのような金属製の相手部品の端部に形成された受圧座面に圧接してシールを行う、例えばＣＮＧ（圧縮天然ガス）、ＤＭＥ（ジメチルエーテル）用配管あるいは燃料用配管などのような高圧流体あるいはブレーキ用配管などの漏洩し易い流体のため有効な金属管と相手部品との接続構造に関するものである。
【０００２】
【従来の技術】
従来この種の金属管と相手部品との端部接続構造は、例えばドイツ連邦共和国特許第４４０７３０６号に開示されているように相手部品の端部の外周面に外ねじを形成するとともに、端面方向に拡大開口した受圧座面を形成し、一方金属管の端部には押圧頭部を成形し、さらに中央部に前記金属管が挿通される貫孔が穿設された底部を有する有底円筒状の袋ナットを、前記押圧頭部の背後の受圧部に当接させて前記相手部品の外ねじに螺合するに伴い前記押圧頭部の押圧座面を受圧座面に押圧、係合して接続するよう構成されていた。
このような従来の技術では、相手部品と金属管の軸芯の中心線が一致（芯出しされた状態）し、かつ相手部品の受圧座面に対する金属管の中心線が倒れのない状態、すなわちミスアライメントがない状態では内部流体に対する確実なシールが得られて、有効なものであった。
【０００３】
【発明が解決しようとする課題】
しかしながら、金属管の中心線と相手部品の中心線とが偏心している場合は、押圧座面と受圧座面との間に片当たりが発生して均一な面圧が得られため接続構造として使用することはできないことは当然であるが、押圧頭部や受圧座面の成形時につぎのような問題が発生することがあった。すなわち、金属管の端部に押圧頭部を成形する際に、チャックとパンチとの僅かな位置ずれにより押圧頭部には図８のように中心線の径方向の僅かなずれγによる偏心が発生したり、あるいは受圧座面が形成される相手部品の中心線と該受圧座面との中心線が受圧座面の形成時にずれた場合に生ずる偏心などによって接続すべき相手部品と金属管の軸芯の中心線が一致しない状態が発生することがあり、また受圧座面に対して接続しようとする金属管の中心線が倒れた状態で袋ナットを締着してしまうことがあった。
【０００４】
このようなミスアライメントのうち前者（偏心した状態）の場合では、例え前記ドイツ連邦共和国特許のように金属管２′の端部に球面状の押圧頭部２′−２を形成し、かつ有底円筒状の袋ナット３′の底部を球面状の凹面３′−１に形成しても、偏心時には図９のように前記押圧頭部２′−２の背後の受圧部２′−４と該袋ナット３′の底部の凹面３′−１とが均一に当接しなくなるために袋ナット３′の底部に片当たりが発生し、その結果偏心量の大きな方の押圧座面２′−３と相手部品１′に形成された受圧座面１′−３との間のシート面における面圧が局部的に低下して内部流体の漏れが発生する可能性があった。
またその端部に截頭円錐状の押圧頭部１２′−２を成形した金属管１２′と円錐状の受圧座面１１′−３を形成した相手部品１１′を接続する場合、袋ナット１３′の螺合の際に後者が発生すると（倒れが発生した時）、図１０に示す通り金属管１２′に発生する倒れにより押圧座面１２′−３と受圧座面１１′−３との間のシール面に片当たりが発生し、これにより十分なシール性を得ることができなかった。
【０００５】
さらに図１１のように金属管２２′の端部に球面状の押圧頭部２２′−２を成形したものにあっては、金属管２２′と相手部品２１′との間に前記前者の状態（偏心）があると、片当たりが発生してシール性を確保することができなかった。また相手部品２１′と金属管２２′の中心線の間に後者の状態（倒れ）が発生した場合、袋ナット２３′の螺合に伴い前記球面状の押圧座面２２′−３が受圧座面２１′−３上を滑動して自動的に芯出しする作用を行うものの、この滑動の際に受圧座面２１′−３の表面が傷付きこの傷により内部流体の漏れが生ずることがあり、また袋ナット２３′の底部２３′−２と球面状の押圧頭部２２′−２の背後の受圧部２２′−４に片当たりが発生して押圧座面２２′−３と受圧座面２１′−３との間のシール性が不十分になることがあった。
【０００６】
本発明は、相手部品と接続すべき金属管との間に中心線の偏心や倒れなどのミスアライメントがあっても、正規に接続された場合と同様なシール性を確保できる金属管と相手部品との接続構造を提供することを目的とするものである。
【０００７】
【課題を解決するための手段】
上記目的を達成するため本発明は、相手部品の端部の外周面に外ねじを形成するとともに、端面方向に拡大開口した受圧座面を形成し、一方金属管の端部には押圧頭部を成形して該頭部の背後の受圧部を前記外ねじに螺合する有底円筒状の袋ナットにて押圧してなる金属管と相手部品との接続構造において、前記押圧頭部の少なくとも押圧座面と背後の受圧部とを球面状となし、該押圧頭部の背後の受圧部と袋ナットの底部との間にその一側面に該受圧部と当接する球面状あるいはテーパ状の凹面を有するカラーを介在させ、該カラーの外径は袋ナットの内周面より小径でかつ中央部に前記金属管の外径より大径の貫孔が形成され、また前記袋ナットの底部の中央部には該金属管より大径であるが前記カラーの外径より小径の貫孔が穿設されていることを特徴とするものであり、前記カラーの軸方向の移動を防止するためのストッパが、該カラーの外周面と前記袋ナットの内周面との間に配設され、また前記押圧頭部における押圧座面の球面の曲率半径と背後の受圧部の球面の曲率半径とが相違してたり、または前記押圧頭部における押圧座面の球面の中心と背後の受圧部の球面の中心が軸芯方向にずれているか、あるいは軸芯方向に重なっているよう構成されたものである。
【０００８】
さらに本発明では前記押圧頭部における押圧座面の球面と背後の受圧部の球面の間に軸芯方向にほぼ平行な直線部あるいは先細りとなったテーパ部を有したり、または前記押圧頭部の先端部には平坦部が設けられていることが好ましい。
【０００９】
【発明の実施の形態】
つぎに本発明を添付図面に基づいて説明する。
図１は本発明に係る金属管と相手部品との接続構造の一実施例を示す縦断面図、図２は本発明で用いたストッパの参考例を示す拡大半截図であって、（ａ）は第１の参考例を示す図、（ｂ）は第２の参考例を示す図、図３は本発明の参考例に係る押圧頭部の形状を示し袋ナットの締付け前の状態の説明図で、（ａ）は第１の参考例を示す図、（ｂ）は第２の参考例を示す図、図４は本発明の他の参考例に係る押圧頭部の形状を示す図で、（ａ）は第１の参考例を示す図、（ｂ）は第２の参考例を示す図、図５は本発明の実施例に係る押圧頭部の形状を示す図で、（ａ）は第１の実施例を示す半截図、（ｂ）は第２の実施例を示す半截図、（ｃ）は第３の実施例を示す側面図、図６は本発明でミスアライメントの状態においての金属管と相手部品との接続状態を示す説明図で、（ａ）は偏心の状態を示す図、（ｂ）は倒れの状態を示す図、図７は本発明に係る金属管と相手部品との接続構造の他の参考例を示す部分半截図であって、１、１１は端金具、継手、噴射ポンプや噴射ノズルなどのような金属製の相手部品、２、１２は金属管、３、１３は袋ナット、４、１４はカラー、５はストッパである。
【００１０】
本発明に係る金属管と相手部品との接続構造の一実施例を図１に基づいて説明すると、相手部品１は厚い肉厚を有し、その端部の外周面には外ねじ１−１が刻設されており、また内部の流通路１−２の一方の端面には該端面方向に拡大開口し、かつ前記流通路１−２の軸芯を中心とした回転面、すなわち円錐面、回転円弧面、回転楕円面、回転放物面、回転双曲線面などの形状を有する受圧座面１−３が形成されている。
そして金属管２は内部に流通路２−１を有する厚肉でも薄肉でもよく、その一端部には塑性加工などによって押圧頭部２−２が成形されており、該押圧頭部の全体が図１の実施例では真球状をなしている。この押圧頭部２−２の先端側は、前記受圧座面１−３に圧接してシールを確保するための球面状の押圧座面２−３となり、一方押圧頭部２−２の背後の球面状の受圧部２−４は後述する袋ナット３の前記外ねじ１−１への螺合に伴いカラー４を介してその軸力を押圧座面２−３へ伝えるものである。
【００１１】
さらに相手部品１の外ねじ１−１に螺合するための内ねじ３−１を内周面に有し、かつ有底円筒状の袋ナット３にはその平坦な底部３−２の中央部に金属管２が挿通するための貫孔３−３が設けられており、該貫孔３−３の内径は後述するカラーの外径より小径であれば機械的強度を損なわない限り大径とすることが好ましい。
【００１２】
そして本発明では、袋ナット３の平坦な底部３−２と押圧頭部２−２の背後の受圧部２−４との間にカラー４が介在されており、該カラーの一側面には受圧部２−４と当接するよう該受圧部２−４と同等もしくはやや大きい曲率半径の球面またはテーパ面の凹面４−１が形成されている。またカラー４の外径は袋ナット３の内周面と間隔をおくよう小径であって、かつ中央部には金属管２が挿通するための貫孔４−２が穿設されており、該貫孔４−２の内径は前記押圧頭部２−２の外径より小径であれば機械的強度を損なわない限り大径とすることが好ましい。換言するとカラー４は、袋ナット３の締付け前の状態では袋ナット３に対しても、また金属管２に対しても遊嵌状態となっているものである。
【００１３】
このように構成された接続構造を用いて相手部品１に金属管２を接続する場合、相手部品１の端面に形成された受圧座面１−３に、金属管２の押圧頭部２−２の押圧座面２−３を当接した状態で、袋ナット３の内ねじ３−１を相手部品１の端部外周面に刻設された外ねじ１−１に螺合するに伴い、介在したカラー４の凹面４−１が押圧頭部２−２の背後の受圧部２−４を押圧し、これにより押圧座面２−３が受圧座面１−３に圧接されて確実なシールを得ることができる。
【００１４】
一方金属管２が相手部品１に対してミスアライメントの状態である場合について図６に基づいて説明すると、まず相手部品１の軸芯の中心線ｌ_１と金属管２の中心線ｌ_２が互いにずれている場合でも、図６（ａ）に示す通りカラー４が袋ナット３の螺合に伴って袋ナット３の平坦な底部３−２を滑動して径方向に移動するためカラー４の凹面４−１と受圧部２−４との係合を保ち袋ナット３の螺合に伴う軸力を受けて押圧座面２−３が受圧座面１−３に片当たりすることなく圧接され、正規の接続状態と同様なシール性を確保することができる。
また相手部品１の中心線ｌ_１に対して金属管２の中心線ｌ_２が角度が付くよう倒れた状態で袋ナット３の螺合が進行しても、図６（ｂ）に示す通り受圧部２−４と球面状またはテーパ面の凹面４−１との係合によってカラー４が袋ナット３の平坦な底部３−２を径方向に滑動して前記倒れに追随するために前記図６（ａ）の場合と同様に正規の接続状態と同様なシール性を確保することができるのである。
【００１５】
つぎに図２は本発明の参考例を示す図であって、この参考例では金属管２と相手部品１とを接続するまでの、例えば保管時や運搬時などに袋ナット３からカラー４が外れて袋ナット３や金属管２の押圧頭部２−２と衝突して傷が付いたり、あるいは破損することを防止するためにストッパ５を設けられたものである。
すなわち、図２（ａ）ではストッパ５はカラー４の外周面に形成された環状の凹溝４−３に嵌合された幅広の、例えばゴム製の弾性Ｏリング５−１からなり、該Ｏリング５−１の外周面を袋ナット３の内周面に圧接してこのＯリングの摩擦力によりカラー４を袋ナット３の内部に仮止めして保持するよう構成したものである。
【００１６】
また図２（ｂ）ではストッパ５は袋ナット３の内周面に圧接するように配設された幅広の樹脂製フリクションリング５−２からなるものであり、該フリクションリング５−２の内周側の側縁面においてカラー４の底面を支持してカラー４を袋ナット３の内部に仮止めして保持するよう構成したものである。
【００１７】
本発明の他の参考例を図３に基づいて説明する。
この参考例では押圧座面２−２の形状を図１の真球状に替えて押圧座面２−３側と受圧部２−４側とで異なる曲率半径に形成したものである。
すなわち図３（ａ）では受圧部２−４側の曲率半径（ｒ１）を押圧座面２−３側のそれ（ｒ２）よりも大きく形成したものである。図３（ａ）の場合は押圧座面２−３側の曲率半径（ｒ２）が小さいために受圧座面１−３に対する円形のシール線の径も小さくなり、受圧座面１−３と押圧座面２−３との間のシート面の面圧が上がるためにシール性向上の効果が一層発揮できる。一方図３（ｂ）では同図（ａ）とは対照的に受圧部２−４側の曲率半径（ｒ１）を押圧座面２−３側のそれ（ｒ２）よりも小さく形成したものであるが、受圧座面１−３と押圧座面２−３との間のシート面の面圧を上げるためには両者の曲率半径の差は余り大きくない方が好ましい。なおこの図３（ｂ）の参考例を用いると、図６（ｂ）のように金属管２に倒れが発生した時にカラー４の径方向の移動が少なくなるために袋ナット３の内周面との当接までの距離を長く取ることができ、したがって大きな倒れにも追随できるようになるのである。
【００１８】
さらに押圧頭部２−２の形状は図３に示す以外にも図４に示す形状を採用することができる。すなわち図４（ａ）のように受圧部２−４側の曲率半径（ｒ_１）の中心（ｃ_１）と押圧座面２−３側の曲率半径（ｒ_２）の中心（ｃ_２）とが間隔αをおいて軸芯方向にずれて形成したり、図４（ｂ）のように受圧部２−４側の曲率半径（ｒ_１）の中心（ｃ_１）と押圧座面２−３側の曲率半径（ｒ_２）の中心（ｃ_２）とが間隔βをおいて軸芯方向に重なりあって、すなわち受圧部２−４側の曲率半径（ｒ_１）の中心（ｃ_１）が軸芯方向の下側に位置し、一方押圧座面２−３側の曲率半径（ｒ_２）の中心（ｃ_２）が軸芯方向の上側に位置するように形成しても作用効果には何ら差異がない。
【００１９】
なお図４の参考例において受圧部２−４側の曲率半径（ｒ１）と押圧座面２−３側の曲率半径（ｒ２）とは同一であっても、また図３のように両曲率半径（ｒ１、ｒ２）とが異なっていても本発明の押圧頭部２−２に適用できることはいうまでもなく、またこのような特殊な形状に押圧頭部を成形する際に、例え図８のようなずれγが生じた金属管でも本発明では支障なく用いることができる。
【００２０】
そして本発明では図５のように押圧頭部２−２の外面の一部分に直線部あるいはテーパ部を設けることが好ましい。すなわち図５（ａ）のように押圧頭部２−２における受圧部２−４と押圧座面２−３の間の移行部において金属管２の軸芯方向にほぼ平行な直線部２−５を環状に設けると、袋ナット３の螺合による締付けの際に加わる軸力によって前記直線部２−５が撓むために馴染み性が向上する。
また図５（ｂ）のように押圧頭部２−２における受圧部２−４と押圧座面２−３の間の移行部において金属管２の先端部に向けて先細りとなるテーパ部２−６を環状に設けると、押圧座面２−３の曲率半径が小さくなり受圧座面１−３に対する円形のシール線の径も小さくなるために面圧が上昇するとともに、図５（ａ）と同様に袋ナット３の螺合による締付けの際に加わる軸力によって前記直線部２−５が撓むために馴染み性も向上する。
さらに図５（ｃ）のように押圧頭部２−２の押圧座面２−３の先端部に軸芯に直交する平坦部２−７を設けると金属管２の内部の流通路２−１の出口先端に、割れや変形の原因となるエッジ部が形成されず、耐久性を向上することができる。
【００２１】
以上述べた実施例においては、相手部品１の端部外周面に刻設された外ねじ１−１に螺合する袋ナット３により相手部品１と金属管２を接続する構成を説明した。しかしミスアライメントの程度が大きい場合には多少の不都合があるが、本発明は雄ナットにより金属管と相手部品とを接続する構成にも適用することができ、このような構成について図７に基づいて説明する。
【００２２】
すなわち、図７に図示する金属管と相手部品と接続構造においては、相手部品１１はその端面に円柱状の凹部１１−４が形成され、該凹部１１−４の内周面には内ねじ１１−５が刻設されており、また内部の流通路１１−２の一方の端面には前記凹部１１−４方向に拡大開口し、かつ前記流通路１１−２の軸芯を中心とした回転面、すなわち円錐面、回転円弧面、回転楕円面、回転放物面、回転双曲線面などの形状を有する受圧座面１１−３が形成されている。
また金属管１２は内部に流通路１２−１を有する厚肉でも薄肉でもよく、その一端部には塑性加工などによって押圧頭部１２−２が成形されており、該押圧頭部の全体が図７の参考例では真球状をなしている。この押圧頭部１２−２の先端側は、前記受圧座面１１−３に圧接してシールを確保するための球面状の押圧座面１２−３となり、一方押圧頭部の背後の球面状の受圧部１２−４は後述する雄ナット１３の前記内ねじ１１−５への螺合に伴いカラー１４を介して軸力を押圧座面１２−３へ伝えるものである。
なお図７では押圧頭部１２−２の形状として真球状をなしたものを図示したが、図３〜図５に示した形状の押圧頭部を使用できることはいうまでもない。
【００２３】
さらに相手部品１１の内ねじ１１−５に螺合するための外ねじ１３−１を外周面に有する雄ナット１３には、中央部に金属管１２が挿通するための貫孔１３−３が設けられており、該貫孔１３−３の内径は後述するカラー１４の外径より小径であれば機械的強度を損なわない限り大径とすることが好ましく、また該貫孔１３−３をカラー１４に向いて先細りとなるテーパ状に形成すると、金属管１２の角度をもった倒れに対応する構造とすることができる。
そしてこの参考例では、雄ナット１３の先端部１３−２と押圧頭部１２−２の背後の受圧部１２−４との間にカラー１４が介在されており、該カラーの一側面には受圧部１２−４と当接するよう該受圧部１２−４と同等もしくはやや大きい曲率半径の球面またはテーパ面の凹面１４−１が形成されている。またカラー１４の外径は凹部１１−４の内周面と間隔をおくよう小径であって、かつ中央部には金属管１２が挿通するための貫孔１４−２が穿設されており、該貫孔１４−２の内径は前記押圧頭部１２−２の外径より小径であれば機械的強度を損なわない限り大径とすることが好ましい。換言すると図７の参考例においてもカラー１４は、雄ナット１３の締付け前の状態では凹部１１−４の内周面に対しても、また金属管１２に対しても遊嵌状態となっているものである。
そして図７の参考例でもミスアライメントがあった場合、正規の接続状態と同様なシール性を確保できる。
【００２４】
【発明の効果】
以上述べた通り本発明によれば、特にＣＮＧ、ＤＭＥあるいは各種の高圧燃料などのような高圧流体が内部を流通する金属管を相手部品に接続するに際して、金属管と相手部品の軸芯の中心線が正しく一致し、かつ金属管と相手部品の中心線に倒れがない正規の接続状態のみならず、例え相手部品と接続すべき金属管との間に中心線の偏心や倒れなどのミスアライメントがあっても、前記した正規に接続された場合と同様なシール性を確保できるので、成形時に厳格な精度を要せず金属管や相手部品を製造することが可能な金属管と相手部品との接続構造を提供することができるものである。
【図面の簡単な説明】
【図１】本発明に係る金属管と相手部品との接続構造の一実施例を示す縦断面図である。
【図２】本発明で用いたストッパの参考例を示す拡大半截図であって、（ａ）は第１の参考例を示す図、（ｂ）は第２の参考例を示す図である。
【図３】本発明の参考例に係る押圧頭部の形状を示し袋ナットの締付け前の状態の説明図で、（ａ）は第１の参考例を示す図、（ｂ）は第２の参考例を示す図である。
【図４】本発明の他の参考例に係る押圧頭部の形状を示す図で、（ａ）は第１の参考例を示す図、（ｂ）は第２の参考例を示す図である。
【図５】本発明の実施例に係る押圧頭部の形状を示す図で、（ａ）は第１の実施例を示す半截図、（ｂ）は第２の実施例を示す半截図、（ｃ）は第３の実施例を示す側面図である。
【図６】本発明でミスアライメントの状態においての金属管と相手部品との接続状態を示す説明図で、（ａ）は偏心の状態を示す図、（ｂ）は倒れの状態を示す図である。
【図７】本発明に係る金属管と相手部品との接続構造の他の参考例を示す部分半截図である。
【図８】押圧頭部に発生した偏心状態の説明図である。
【図９】ミスアライメントの状態が発生した従来技術の一例を示す縦断面の説明図である。
【図１０】ミスアライメントの状態が発生した従来技術の他の例を示す縦断面の説明図である。
【図１１】ミスアライメントの状態が発生した従来技術のさらに他の例を示す縦断面の説明図である。
【符号の説明】
１、１１相手部品
１−１、１３−１外ねじ
１−２、２−１、１１−２、１２−１流通路
１−３、１１−３受圧座面
２、１２金属管
２−２、１２−２押圧頭部
２−３、１２−３押圧座面
２−４、１２−４受圧部
２−５直線部
２−６テーパ部
２−７平坦部
３、１３ナット
３−１、１１−５内ねじ
３−２底部
３−３、４−２、１３−３、１４−２貫孔
４、１４カラー
４−１、１４−１凹面
４−３凹溝
５ストッパ
５−１弾性Ｏリング
５−２樹脂製フリクションリング
１１−４凹部
１３−２先端部
ｃ１、ｃ２中心
ｌ１、ｌ２中心線
ｒ１、ｒ２曲率半径
α、β 間隔[0001]
BACKGROUND OF THE INVENTION
The present invention generally relates to a press seat formed at a pipe end of a relatively thin, thin or thick metal tube that is provided as an oil supply or supply air supply passage in an automobile or various machines and devices. The surface is pressed against a pressure-receiving seat surface formed at the end of a metal mating part such as an end fitting, a joint, an injection pump, an injection nozzle, etc., for example, CNG (compressed natural gas), DME ( The present invention relates to a connection structure between a metal pipe and a counterpart component that is effective for high-pressure fluid such as dimethyl ether) pipe or fuel pipe or fluid that easily leaks such as brake pipe.
[0002]
[Prior art]
Conventionally, this kind of end connection structure between a metal tube and a mating part is formed by forming an external thread on the outer peripheral surface of the end of the mating part as disclosed in German Patent No. 4407306, for example. A bottomed cylinder having a pressure receiving seat surface that is enlarged and opened, while a pressing head is formed at the end of the metal tube, and a bottom is formed with a through hole through which the metal tube is inserted at the center. As the cap nut is brought into contact with the pressure receiving portion behind the pressing head and screwed into the external screw of the mating part, the pressing seat surface of the pressing head is pressed and engaged with the pressure receiving seat surface. Was configured to connect.
In such a conventional technique, the center line of the center axis of the mating part and the metal tube is aligned (centered), and the center line of the metal pipe with respect to the pressure receiving seating surface of the mating part is not tilted, that is, In the absence of misalignment, a reliable seal against the internal fluid was obtained, which was effective.
[0003]
[Problems to be solved by the invention]
However, when the center line of the metal tube and the center line of the mating part are eccentric, a single contact occurs between the pressing seat surface and the pressure-receiving seat surface, and a uniform surface pressure is obtained. Of course, the following problems may occur when molding the pressing head and the pressure-receiving seat surface. That is, when the pressing head is formed at the end of the metal tube, the pressing head has an eccentricity due to a slight deviation γ in the radial direction of the center line as shown in FIG. If the center line between the center line of the mating part on which the pressure-receiving seat surface is formed and the pressure-receiving seat surface is shifted when the pressure-receiving seat surface is formed, the mating part and the metal tube to be connected due to eccentricity etc. A state where the center lines of the shaft cores do not coincide with each other may occur, and the cap nut may be tightened in a state where the center line of the metal tube to be connected to the pressure receiving seat surface is tilted.
[0004]
In the case of the former (eccentric state) among such misalignments, a spherical pressing head 2'-2 is formed at the end of the metal tube 2 'as in the above-mentioned German patent, and it is present. Even if the bottom portion of the bottom cylindrical cap nut 3 'is formed into a spherical concave surface 3'-1, the pressure receiving portion 2'-4 behind the pressing head 2'-2 and the pressure receiving portion 2'-4 as shown in FIG. Since the concave surface 3'-1 at the bottom of the cap nut 3 'does not uniformly contact, the bottom of the cap nut 3' is caused to come into contact with one another. As a result, the pressing seat surface 2'-3 having the larger eccentric amount. There is a possibility that the surface pressure on the seat surface between the pressure receiving seat surface 1'-3 formed on the mating part 1 'is locally reduced and internal fluid leaks.
When connecting a metal tube 12 'formed with a truncated conical pressing head 12'-2 and a mating part 11' formed with a conical pressure receiving seat surface 11'-3 at its end, a cap nut 13 If the latter occurs during the screwing of '(when the collapse occurs), as shown in FIG. 10, the collapse of the metal tube 12' causes the press seat surface 12'-3 and the pressure receiving seat surface 11'-3 to fall. One-sided contact occurred on the sealing surface in the meantime, and sufficient sealing performance could not be obtained.
[0005]
Further, in the case where a spherical pressing head 22'-2 is formed at the end of the metal tube 22 ' as shown in FIG. 11, the former state is provided between the metal tube 22' and the mating part 21 '. When (eccentric) is, it could not be ensured sealing property is uneven contact occurs. When the latter state (falling) occurs between the mating part 21 'and the center line of the metal tube 22', the spherical pressing seat surface 22'-3 becomes the pressure receiving seat as the cap nut 23 'is screwed. Although it slides on the surface 21'-3 and automatically centers, the surface of the pressure-receiving seat surface 21'-3 is damaged during the sliding, and internal fluid may leak due to this scratch. Also, the bottom 23'-2 of the cap nut 23 'and the pressure receiving portion 22'-4 behind the spherical pressing head 22'-2 are caused to come into contact with each other so that the pressing seat surface 22'-3 and the pressure receiving seat surface In some cases, the sealing property between 21'-3 and the 21'-3 becomes insufficient.
[0006]
The present invention provides a metal tube and a mating part that can ensure the same sealing performance as that of a regular connection even if there is misalignment such as eccentricity or tilt of the center line between the mating part and the metal pipe to be connected. It is an object to provide a connection structure.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention forms an external thread on the outer peripheral surface of the end portion of the mating part, and forms a pressure receiving seat surface that opens in the direction of the end surface, while a pressing head on the end portion of the metal tube In the connection structure between the metal tube and the mating part formed by pressing the pressure receiving portion behind the head with a bottomed cylindrical cap nut screwed into the outer screw, at least of the pressing head A spherical surface or a tapered concave surface that contacts the pressure receiving portion on one side surface between the pressure receiving portion behind the pressing head and the bottom of the cap nut. A collar having an outer diameter smaller than the inner peripheral surface of the cap nut and having a through hole larger in diameter at the center than the outer diameter of the metal tube, and the center of the bottom of the cap nut A through hole having a diameter larger than that of the metal tube but smaller than the outer diameter of the collar is formed in the portion. A stopper for preventing the collar from moving in the axial direction is disposed between the outer peripheral surface of the collar and the inner peripheral surface of the cap nut, and the pressing head The radius of curvature of the spherical surface of the pressing seat surface in the portion is different from the radius of curvature of the spherical surface of the pressure receiving portion behind, or the center of the spherical surface of the pressing seat surface in the pressing head and the center of the spherical surface of the pressure receiving portion behind It is configured to be displaced in the axial direction or overlap in the axial direction.
[0008]
Furthermore, in the present invention, a linear portion or a tapered portion that is substantially parallel to the axial direction is provided between the spherical surface of the pressing seat surface and the spherical surface of the pressure receiving portion in the pressing head, or the pressing head It is preferable that the flat part is provided in the front-end | tip part.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of a connection structure between a metal tube and a mating part according to the present invention, and FIG. 2 is an enlarged half view showing a reference example of a stopper used in the present invention. Is a diagram showing a first reference example, (b) is a diagram showing a second reference example, FIG. 3 is a diagram showing the shape of the pressing head according to the reference example of the present invention, and an explanatory diagram of a state before the cap nut is tightened (A) is a diagram showing a first reference example, (b) is a diagram showing a second reference example, FIG. 4 is a diagram showing the shape of a pressing head according to another reference example of the present invention, (a) is a view diagram illustrating a first reference example, (b) is showing the shape of the pressing head according to actual施例figure 5 the invention showing a second reference example, (a) FIG. 6B is a half view showing the first embodiment, FIG. 6C is a side view showing the third embodiment, and FIG. 6 is a misalignment state according to the present invention. Metal pipes and mating parts FIG. 7A is a diagram showing an eccentric state, FIG. 7B is a diagram showing a collapsed state, and FIG. 7 is a diagram showing another connection structure between a metal tube and a mating part according to the present invention. a partial half-cut view showing a reference example of, 1, 11 end fittings, couplings, metal mating part such as the injection pump and the injection nozzle, 2,12 metal pipe, 3, 13 cap nut, 4 and 14 are collars, and 5 is a stopper.
[0010]
An embodiment of a connection structure between a metal tube and a mating component according to the present invention will be described with reference to FIG. 1. The mating component 1 has a thick wall, and an outer screw 1-1 is provided on the outer peripheral surface of the end portion. Are engraved, and one end face of the internal flow passage 1-2 has an enlarged opening in the direction of the end face, and a rotational surface around the axial center of the flow passage 1-2, that is, a conical surface, A pressure receiving seat surface 1-3 having a shape such as a rotating arc surface, a rotating ellipsoid surface, a rotating paraboloid surface, a rotating hyperbolic surface, or the like is formed.
The metal tube 2 may be thick or thin having a flow passage 2-1 inside, and a pressing head 2-2 is formed at one end thereof by plastic working or the like. In one embodiment, it is spherical. The front end side of the pressing head 2-2 is a spherical pressing seat surface 2-3 that presses against the pressure-receiving seat surface 1-3 to ensure a seal, and is behind the pressing head 2-2. The spherical pressure receiving portion 2-4 transmits the axial force to the pressing seat surface 2-3 via the collar 4 when the cap nut 3 described later is screwed onto the external screw 1-1.
[0011]
Further, an inner screw 3-1 for screwing onto the outer screw 1-1 of the counterpart part 1 is provided on the inner peripheral surface, and the bottomed cylindrical cap nut 3 has a central portion of its flat bottom 3-2. Is provided with a through hole 3-3 through which the metal tube 2 is inserted, and the inner diameter of the through hole 3-3 is smaller than the outer diameter of the collar, which will be described later, as long as the mechanical strength is not impaired. It is preferable to do.
[0012]
In the present invention, the collar 4 is interposed between the flat bottom portion 3-2 of the cap nut 3 and the pressure receiving portion 2-4 behind the pressing head portion 2-2. A spherical surface or a tapered concave surface 4-1 having a radius of curvature equal to or slightly larger than that of the pressure receiving portion 2-4 is formed so as to contact the portion 2-4. The outer diameter of the collar 4 is small so as to be spaced from the inner peripheral surface of the cap nut 3, and a through-hole 4-2 for inserting the metal tube 2 is formed in the center portion. If the inner diameter of the through hole 4-2 is smaller than the outer diameter of the pressing head 2-2, it is preferable that the inner diameter of the through hole 4-2 is larger as long as the mechanical strength is not impaired. In other words, the collar 4 is loosely fitted to the cap nut 3 and the metal tube 2 before the cap nut 3 is tightened.
[0013]
When the metal tube 2 is connected to the mating component 1 using the connection structure configured as described above, the pressing head 2-2 of the metal tube 2 is placed on the pressure receiving seat surface 1-3 formed on the end surface of the mating component 1. The inner screw 3-1 of the cap nut 3 is engaged with the outer screw 1-1 engraved on the outer peripheral surface of the end of the mating component 1 with the pressing seat surface 2-3 in contact. The concave surface 4-1 of the collar 4 presses the pressure receiving portion 2-4 behind the pressing head 2-2, so that the pressing seat surface 2-3 is pressed against the pressure receiving seat surface 1-3 and provides a reliable seal. Obtainable.
[0014]
On the other hand, the case where the metal tube 2 is misaligned with the counterpart component 1 will be described with reference to FIG. 6. First, the centerline l ₁ of the axis of the counterpart component 1 and the centerline l 2 of the metal tube ₂ are mutually connected. 6A, the collar 4 slides on the flat bottom portion 3-2 of the cap nut 3 as the cap nut 3 is screwed and moves in the radial direction as shown in FIG. 4-1 and the pressure receiving portion 2-4 are kept engaged, and the pressing seat surface 2-3 is pressed against the pressure receiving seat surface 1-3 by receiving an axial force accompanying the screwing of the cap nut 3, It is possible to ensure the same sealing performance as in a normal connection state.
Also in progress is screwed cap nut 3 in a state where the center line l ₂ of the metal tube 2 with respect to the center line l ₁ of the mating component 1 has fallen to the angle stick, as pressure shown in FIG. 6 (b) The collar 4 slides in the radial direction on the flat bottom 3-2 of the cap nut 3 by the engagement of the portion 2-4 with the spherical or tapered concave surface 4-1, and follows the above-described collapse. As in the case of (a), it is possible to ensure the same sealing performance as in the normal connection state.
[0015]
Next, FIG. 2 is a diagram showing a reference example of the present invention. In this reference example, the collar 4 is moved from the cap nut 3 until the metal tube 2 and the mating part 1 are connected, for example, during storage or transportation. A stopper 5 is provided to prevent the bag nut 3 and the pressing head 2-2 of the metal tube 2 from colliding and being damaged or damaged.
That is, in FIG. 2A, the stopper 5 is formed of a wide elastic O-ring 5-1 made of rubber, for example, fitted in an annular groove 4-3 formed on the outer peripheral surface of the collar 4. The outer peripheral surface of the ring 5-1 is pressed against the inner peripheral surface of the cap nut 3, and the collar 4 is temporarily fixed and held inside the cap nut 3 by the frictional force of the O-ring.
[0016]
In FIG. 2B, the stopper 5 comprises a wide resin friction ring 5-2 disposed so as to be in pressure contact with the inner peripheral surface of the cap nut 3, and the inner periphery of the friction ring 5-2. The bottom surface of the collar 4 is supported on the side edge surface on the side, and the collar 4 is temporarily fixed inside the cap nut 3 and held.
[0017]
Another reference example of the present invention will be described with reference to FIG.
In this reference example, the shape of the pressing seat surface 2-2 is changed to the true sphere shown in FIG. 1 and formed with different radii of curvature on the pressing seat surface 2-3 side and the pressure receiving portion 2-4 side.
That is, in FIG. 3A, the curvature radius (r1) on the pressure receiving portion 2-4 side is formed larger than that (r2) on the pressing seat surface 2-3 side. In the case of FIG. 3A, since the radius of curvature (r2) on the pressing seat surface 2-3 side is small, the diameter of the circular seal line with respect to the pressure receiving seat surface 1-3 is also reduced. Since the surface pressure of the seat surface between the seat surface 2-3 is increased, the effect of improving the sealing performance can be further exhibited. On the other hand, in FIG. 3B, in contrast to FIG. 3A, the radius of curvature (r1) on the pressure receiving portion 2-4 side is formed smaller than that (r2) on the pressing seat surface 2-3 side. However, in order to increase the surface pressure of the seat surface between the pressure-receiving seat surface 1-3 and the pressing seat surface 2-3, it is preferable that the difference in curvature radius between the two is not so large. If the reference example of FIG. 3 (b) is used, the radial movement of the collar 4 is reduced when the metal tube 2 is tilted as shown in FIG. 6 (b). It is possible to increase the distance to the contact with the head, so that it is possible to follow a large fall.
[0018]
Furthermore, the shape shown in FIG. 4 can be adopted as the shape of the pressing head 2-2 in addition to the shape shown in FIG. That is, as shown in FIG. 4A, the center (c ₁ ) of the curvature radius (r ₁ ) on the pressure receiving portion 2-4 side and the center (c ₂ ) of the curvature radius (r ₂ ) on the pressing seat surface 2-3 side. Are shifted in the axial direction at an interval α, or the center (c ₁ ) of the radius of curvature (r ₁ ) on the pressure receiving portion 2-4 side and the pressing seat surface 2-3 as shown in FIG. 4B. and overlapping the center (c ₂₎ and the axial direction at a distance β of curvature of the side radius (r _2), that is, the center of the pressure receiving portion 2-4 side of the curvature radius (r _₁₎ (c ₁₎ is Even if it is formed so that the center (c ₂ ) of the curvature radius (r ₂ ) on the one side of the pressing seat surface 2-3 is positioned on the upper side in the axial direction, it is located on the lower side in the axial direction. There is no difference.
[0019]
In the reference example of FIG. 4, even if the curvature radius (r1) on the pressure receiving portion 2-4 side and the curvature radius (r2) on the pressing seat surface 2-3 side are the same, both radii of curvature are as shown in FIG. It goes without saying that even if (r1, r2) is different, it can be applied to the pressing head 2-2 of the present invention, and when the pressing head is formed into such a special shape, for example, as shown in FIG. Even a metal tube having such a deviation γ can be used without any problem in the present invention.
[0020]
And in this invention, it is preferable to provide a linear part or a taper part in a part of outer surface of the press head 2-2 like FIG. That is, as shown in FIG. 5A, a straight portion 2-5 substantially parallel to the axial direction of the metal tube 2 at the transition portion between the pressure receiving portion 2-4 and the pressing seat surface 2-3 in the pressing head 2-2. Since the linear portion 2-5 is bent by the axial force applied when the cap nut 3 is tightened by screwing, the conformability is improved.
Further, as shown in FIG. 5B, the tapered portion 2- tapering toward the tip of the metal tube 2 at the transition portion between the pressure receiving portion 2-4 and the pressing seat surface 2-3 in the pressing head 2-2. When the ring 6 is provided in an annular shape, the radius of curvature of the pressing seat surface 2-3 is reduced and the diameter of the circular seal line with respect to the pressure receiving seat surface 1-3 is also reduced, so that the surface pressure increases, and FIG. Similarly, since the linear portion 2-5 is bent by the axial force applied when the cap nut 3 is screwed, the conformability is improved.
Further, when a flat portion 2-7 perpendicular to the axis is provided at the tip of the pressing seat surface 2-3 of the pressing head 2-2 as shown in FIG. 5C, the flow passage 2-1 inside the metal tube 2 is provided. The edge part which causes a crack and a deformation | transformation is not formed in the exit front-end | tip of this, but durability can be improved.
[0021]
In the embodiment described above, the configuration in which the counterpart part 1 and the metal tube 2 are connected by the cap nut 3 that is screwed into the external screw 1-1 engraved on the outer peripheral surface of the end part of the counterpart part 1 has been described. However, although there are some inconveniences when the degree of misalignment is large, the present invention can also be applied to a configuration in which a metal tube and a mating part are connected by a male nut. Such a configuration is based on FIG. I will explain.
[0022]
That is, in the connection structure between the metal tube and the counterpart component shown in FIG. 7, the counterpart component 11 is formed with a cylindrical recess 11-4 on the end surface, and an inner screw 11 is formed on the inner peripheral surface of the recess 11-4. -5 is engraved, and one end face of the internal flow passage 11-2 has an enlarged opening in the direction of the recess 11-4, and a rotation surface centered on the axial center of the flow passage 11-2 That is, the pressure-receiving seat surface 11-3 having a shape such as a conical surface, a rotating arc surface, a rotating ellipsoid surface, a rotating paraboloid surface, a rotating hyperbolic surface is formed.
The metal pipe 12 may be thick or thin having a flow passage 12-1 therein, and a pressing head 12-2 is formed at one end thereof by plastic working or the like. In the reference example of FIG. The distal end side of the pressing head 12-2 is a spherical pressing seat surface 12-3 that presses against the pressure receiving seat surface 11-3 to secure a seal, while the spherical shape behind the pressing head 12-2 The pressure receiving portion 12-4 transmits the axial force to the pressing seat surface 12-3 via the collar 14 when the male nut 13 described later is screwed into the inner screw 11-5.
Although FIG. 7 shows a spherical shape as the shape of the pressing head 12-2, it goes without saying that the pressing head having the shape shown in FIGS. 3 to 5 can be used.
[0023]
Furthermore, the male nut 13 having an outer thread 13-1 on the outer peripheral surface for screwing with the inner thread 11-5 of the mating part 11 is provided with a through hole 13-3 for insertion of the metal tube 12 in the center. If the inner diameter of the through-hole 13-3 is smaller than the outer diameter of the collar 14 to be described later, it is preferable that the through-hole 13-3 has a larger diameter as long as the mechanical strength is not impaired. If the taper is tapered toward the end, the metal tube 12 can have a structure corresponding to an angled fall.
In this reference example, a collar 14 is interposed between the tip portion 13-2 of the male nut 13 and the pressure receiving portion 12-4 behind the pressing head 12-2. A spherical surface or a tapered concave surface 14-1 having a radius of curvature equal to or slightly larger than that of the pressure receiving portion 12-4 is formed so as to contact the portion 12-4. Further, the outer diameter of the collar 14 is small so as to be spaced from the inner peripheral surface of the recess 11-4, and a through hole 14-2 through which the metal tube 12 is inserted is formed in the center portion. If the inner diameter of the through hole 14-2 is smaller than the outer diameter of the pressing head 12-2, the inner diameter is preferably larger as long as the mechanical strength is not impaired. In other words, also in the reference example of FIG. 7, the collar 14 is loosely fitted to the inner peripheral surface of the recess 11-4 and to the metal tube 12 before the male nut 13 is tightened. Is.
In the case of misalignment in the reference example of FIG. 7 as well, it is possible to ensure the same sealing performance as that in the normal connection state.
[0024]
【The invention's effect】
As described above, according to the present invention, when connecting a metal pipe in which a high-pressure fluid such as CNG, DME, or various high-pressure fuels circulates to the mating part, the center of the axis of the metal pipe and the mating part is centered. Misalignment such as eccentricity or tilt of the center line between the metal part and the metal tube to be connected, as well as a normal connection state where the lines are correctly aligned and the center line of the metal pipe and the counterpart part does not fall down Even if there is a metal pipe and the mating part that can manufacture the metal pipe and the mating part without requiring strict accuracy at the time of molding because it can ensure the same sealing performance as the case of regular connection as described above The connection structure can be provided.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a connection structure between a metal tube and a mating part according to the present invention.
FIGS. 2A and 2B are enlarged half-sectional views showing a reference example of a stopper used in the present invention, wherein FIG. 2A is a view showing a first reference example, and FIG. 2B is a view showing a second reference example;
FIGS. 3A and 3B are diagrams illustrating a shape of a pressing head according to a reference example of the present invention and illustrating a state before a cap nut is tightened. FIG. 3A is a diagram illustrating a first reference example, and FIG. It is a figure which shows a reference example.
4A and 4B are diagrams showing the shape of a pressing head according to another reference example of the present invention, in which FIG. 4A is a diagram showing a first reference example, and FIG. 4B is a diagram showing a second reference example; .
[5] a view showing the shape of the pressing head according to actual施例of the present invention, (a) shows the half-cut view, (b) the half-cut view of a second embodiment showing a first embodiment, (C) is a side view showing a third embodiment.
6A and 6B are explanatory views showing a connection state between a metal tube and a mating part in a misalignment state according to the present invention, wherein FIG. 6A is a diagram showing an eccentric state, and FIG. is there.
FIG. 7 is a partial semi-circular view showing another reference example of a connection structure between a metal tube and a mating part according to the present invention.
FIG. 8 is an explanatory diagram of an eccentric state generated in the pressing head.
FIG. 9 is an explanatory view of a longitudinal section showing an example of a conventional technique in which a misalignment state occurs.
FIG. 10 is an explanatory view of a longitudinal section showing another example of the prior art in which a misalignment state has occurred.
FIG. 11 is an explanatory view of a longitudinal section showing still another example of the prior art in which a misalignment state has occurred.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 11 Counterpart 1-1, 13-1 External thread 1-2, 2-1, 11-2, 12-1 Flow path 1-3, 11-3 Pressure-receiving seat surface 2, 12 Metal pipe 2-2, 12-2 Pressing head 2-3, 12-3 Pressing seat surface 2-4, 12-4 Pressure receiving part 2-5 Linear part 2-6 Taper part 2-7 Flat part 3, 13 Nut 3-1, 11- 5 Internal thread 3-2 Bottom 3-3, 4-2, 13-3, 14-2 Through hole 4, 14 Collar 4-1, 14-1 Concave surface 4-3 Concave groove 5 Stopper 5-1 Elastic O-ring 5 -2 Resin friction ring 11-4 Recess 13-2 Tip c1, c2 Center l1, l2 Center line r1, r2 Curvature radius α, β Spacing

Claims

An external thread is formed on the outer peripheral surface of the end of the mating part, and a pressure receiving seat surface that is enlarged in the end surface direction is formed. On the other hand, a pressing head is formed on the end of the metal tube to In a connection structure between a metal tube formed by pressing a pressure-receiving part with a bottomed cylindrical cap nut screwed to the external screw and a mating part, at least a pressing seat surface of the pressing head and a pressure-receiving part behind It has a spherical shape, and a collar having a spherical or tapered concave surface that abuts the pressure receiving portion on one side surface is interposed between the pressure receiving portion behind the pressing head and the bottom of the cap nut. The outer diameter is smaller than the inner peripheral surface of the cap nut, and a through-hole is formed in the central portion larger than the outer diameter of the metal tube, and the center portion of the bottom portion of the cap nut is larger in diameter than the metal tube. there is a bored small transmembrane pore than the outer diameter of the collar, the pressing seat surface in the pressing head Connection structure of a metal pipe and the mating part, characterized in that it has a tapered portion which becomes substantially parallel straight portions or tapered in the axial direction between the spherical surface and the back of the pressure receiving portion.