JP4320190B2

JP4320190B2 - Pipe fitting

Info

Publication number: JP4320190B2
Application number: JP2003065456A
Authority: JP
Inventors: 健生木下
Original assignee: Sekisui Chemical Co Ltd
Current assignee: Sekisui Chemical Co Ltd
Priority date: 2003-03-11
Filing date: 2003-03-11
Publication date: 2009-08-26
Anticipated expiration: 2023-03-11
Also published as: JP2004270884A

Description

【０００１】
【発明の属する技術分野】
本発明は、水道管等、内部に正の圧力がかかる配管を急角度にて曲折するような配管に好適に用いられるエルボ型またはチーズ型の管継手に関するものである。
【０００２】
【従来の技術】
従来、合成樹脂製の管と管継手を接続する方法としては、ＴＳ接続、溶接接続、融着接続、メカニカル接続等の各種の接続方法があり、その用途と目的に応じて適宜選択して用いられている。
こうした接続方法を問わず、管継手の外面形状は、水力学的圧力に起因する応力等を負担する強度上の必要と、施工スペースと材料の節約という、相反する要求を満たすように適宜決められている。
【０００３】
それに対して、管継手の内面形状は、水力学的応力に対する強度上の必要と、内部を流れる流体の通り易さの確保という、相反する要求を満たすように適宜定められている。しかし、実際上は、管の内径と略等しい寸法を管継手内径の最低寸法とすることが多く、ＪＩＳ規格等の規格も概略そうしたものとなっている（非特許文献１，２参照。）。
【０００４】
従って、実際の管継手製品においては、管継手本体の管接続部に近接する部分の内面形状も、この最低寸法に近い円であるのが普通である。これは、形状を構成するのに、円という形が最も基本的な幾何学形状であることに加え、水力学的圧力によって管継手材料に発生する応力の最大値を最も軽減できるものと考え、内径をできるだけ小さくし、そのことによって、肉厚を可能な限り大きく確保しようとする自然な思想に基づくものと考えられる。
【０００５】
次に、上記の内容を従来のエルボ型の管継手を例として、図１８〜２４を参照して説明する。
図１８及び１９に示すように、このエルボ型の管継手１００は、中央部の曲折部を有する管継手本体１０１の両端部に管接続部１０２，１０３が設けられている。
管継手本体１０１の両管接続部１０２，１０３側の両端縁（図１８の断面ｂ，ｂ）における内面形状は、図１９及び２０に示すような真円となっている。
従って、両管接続部１０２，１０３の管軸を含む平面と交わる相対する内面部分間の距離ｄ１と該平面から最も遠くなる相対する内面部分間の距離ｄ２とは等しくなっている。また、両端縁において、曲折部の内側となる内面の曲率半径ｒ１と曲折部の外側となる内面の曲率半径ｒ２とは等しくなっている。
【０００６】
それに伴って、この管継手１００は、その管継手本体１０１の曲折部の中央部（図１８の４５°断面ａ）における内面形状は、図２１に示すような形、つまり上部が縦長の楕円形をなしていて頂部のｓ部分が尖り、下部の両側部に出っ張りを有するいわゆるおむすび形の歪みのある形になっている。
【０００７】
それは、その上半分の領域は、両管接続部１０２，１０３側の端縁ｂ，ｂから管継手本体１０１の曲折部の中央部ａに延びる円柱体を斜め４５°に切断したときの端面の形状として現れる、縦軸のみを√２倍に伸ばした縦長の楕円形の上部と同じ形状となり、その下半分の領域は、曲りに合わせたカーブを持つように素直なトーラス面をなすようになるからである。
【０００８】
つまり、この管継手１００を製造するには、図２２に示すような一対のダイス２０１、２０１からなる内型２００が使用される。図２３に示すように、このダイス２０１の曲折部形成部２１１の外形は、先端部側の上半分が円柱体で下半分が曲りに合わせた筒体となっているものを斜め４５°に切断した状態となされるのが普通であるので、成形される管継手１００の管継手本体１０１の曲折部の内面形状は上記のものに決まってしまうこととなるのである。
【０００９】
その結果、この管継手１００を用いて管を接続した配管において、管継手１００の内部に正の静水圧が繰り返しかかった場合に、図２４に示すように、管継手１００の内周、特に管接続部１０２，１０３の両軸に直交する方向に引っ張る力が働き、内面に発生したクラックが外面にまで貫通するように成長して、図中にｃとして示すような傷が入ってしまうという不都合な事態となる。
これは、特に肉の薄い製品については、内圧に伴って壁が引っ張られる、いわゆる膜応力と共に、形状の僅かな出入りに密接に関連するところの管壁を曲げる力が働き、これが材料の局所における大きな応力に結びついていると考えられる。
【００１０】
更に、上記の内容を従来のチーズ型の管継手を例として、図２５〜３０を参照して説明する。
図２５及び２６に示すように、このチーズ型の管継手３００は、断面Ｔ字型をなす管継手本体３０１の主管軸方向の両端縁に、主管接続部３０２，３０３が設けられており、主管軸と直交する枝管軸方向の端縁に枝管接続部３０４が設けられている。
この管継手３００では、管継手本体３０１の主管接続部３０２，３０３側の端縁（図２５の断面ｄ，ｄ）における内面形状は、図２７に示すような直径ｄ３の真円となっており、枝管接続部３０４側の端縁（図２５の断面ｅ）における内面形状も真円となっている。
【００１１】
それに伴って、この管継手３００は、その管継手本体３０１の主管接続部３０２，３０３と枝管接続部３０４の境界部（図２５の４５°断面ｆ，ｆ）における内面形状は、縦長の楕円形の上半分をなしていて頂部のｔ部分が尖った形になっている。
【００１２】
これは、その上半分の領域は、両主管接続部３０２，３０３側の端縁（図２５の断面ｄ，ｄ）から管継手本体１０１の曲折部の中央部に延びる円柱体の上部を斜め４５°に切断したときの端面の形状として現れる、縦軸のみを√２倍に伸ばした縦長の楕円形の上部と同じ形状となるからである。
【００１３】
つまり、この管継手３００を製造するには、図２９に示すような主管成形用ダイス４０１、４０１と枝管成形用ダイス４０２からなる内型４００が使用される。
このうち、主管成形用ダイス４０１の曲折部形成部４１１の外形は、先端部側の上半分が円柱体で下半分が曲りに合わせた筒体となっているものの上半分を斜め４５°に切断し、下半分を垂直に切断したものを用いるのが普通であり、枝管成形用ダイス４０２の外形は、その先端面が、主管成形用ダイス４０１、４０１の先端面に対応するものを用いるのが普通であるので、成形される管継手３００の主管接続部３０２，３０３と枝管接続部３０４の境界部の内面形状は上記のものに決まってしまうこととなるのである。
【００１４】
その結果、この管継手３００を用いて管を接続した配管において、管継手３００の内部に正の静水圧が繰り返しかかった場合に、図３０に示すように、管継手３００の内周、特に主管接続部３０２，３０３の主軸と枝管接続部３０４の枝管軸に直交する方向に引っ張る力が働き、内面に発生したクラックが外面にまで貫通するように成長して、図中にｇと示すような傷が入ってしまうという不都合な事態となる。
これは、特に肉の薄い製品については、内圧に伴って壁が引っ張られる、いわゆる膜応力と共に、形状の僅かな出入りに密接に関連するところの管壁を曲げる力が働き、これが材料の局所における大きな応力に結びついていると考えられる。
【００１５】
【非特許文献１】
ＪＩＳＫ６７４２
【非特許文献２】
ＪＩＳＫ６７４３
【００１６】
【発明が解決しようとする課題】
上記のような従来の問題点に鑑み、水力学的圧力に起因する管継手に作用する応力への対策として、肉厚をひたすら厚くするのではなく、場所によってはむしろ肉厚を薄くし、従って材料を節約しつつも、その場所に肉を盛った場合と比べても、強度において優れた管継手製品を提供することを目的とする。
【００１７】
また、本発明は、製品の内面及び外面を形成する技術手段として、主として、射出成形や圧縮成形等の一般に再使用される型を用いて成形することを前提とする。
一般に再使用される型は、管継手のような形状に対しては、外面を形成するキャビティと呼ばれる部分と、内面を形成するコアと呼ばれる部分とから構成されるが、中でもコアについては、設計上の要求難度が高い。それは製品一個の成形に供せられた後、製品を壊すことなく、狭い内面から無事に引き抜ける形状又は機構を持つ必要があるからである。
【００１８】
本発明は、成形方法に固有の制約の下に、水道管等、内部に正の圧力がかかる配管を急角度にて曲折するように配管する際に、内外圧差、特にその使用中の圧力変動に伴って継手材料に発生する応力の最大値を低減し、こうした応力に伴って長期的に進行する破壊を低減すべく、力学的耐性を向上させたエルボ型またはチーズ型の管継手を提供することを目的とする。
【００１９】
【課題を解決するための手段】
本願の請求項１に記載の発明は、曲折部を有する管継手本体の両端縁部に、断面円形の管を接続可能な管接続部が設けられたＬ字状エルボ型の管継手であって、前記管継手本体の両管接続部側の端縁部において、前記両管接続部の管軸を共に含む平面と交わる相対する内面部分間の距離Ｄ１が該平面から最も遠くなる相対する内面部分間の距離Ｄ２よりも小さく、かつ、その距離の差Ｄ２−Ｄ１が前記接続すべき管の厚さの半分以上２倍以下の範囲となる関係を満たすような内面形状とされている管継手である。
【００２０】
その距離の差Ｄ２−Ｄ１が接続すべき管の厚さの半分未満であると、有効な改善効果を得ることができず、接続すべき管の厚さの２倍を超えると、管継手に管を接続するメカニズムに支障をきたすか、または内部に通す流体の通行を阻害するかのいずれかの問題が予想される。
【００２１】
本願の請求項２に記載の発明は、前記管継手本体の両管接続部側の端縁部において、曲折部の内側となる内面の曲率半径Ｒ１が曲折部の外側となる内面の曲率半径Ｒ２よりも大きく、その曲率半径の差Ｒ１−Ｒ２が前記接続すべき管の厚さの４倍以下の範囲となる関係を満たすような内面形状とされている請求項１に記載の管継手である。
【００２２】
その曲率半径の差Ｒ１−Ｒ２の下限は特にないが、有効な改善効果を得るためには、接続すべき管の肉厚の半分以上が好ましい。曲率半径の差Ｒ１−Ｒ２が接続すべき管の厚さの４倍を超えると、管継手に管を接続するメカニズムに支障をきたすか、または内部に通す流体の通行を阻害するかのいずれかの問題が予想される。
【００２３】
本願の請求項３に記載の発明は、断面Ｔ字型をなす管継手本体の各端縁部に、断面円形の管を接続可能な管接続部が設けられたチーズ型の管継手であって、前記管継手本体の各管接続部側の端縁部において、前記各管接続部の管軸を全て含む平面と交わる相対する内面部分間の距離Ｄ３が該平面から最も遠くなる相対する内面部分間の距離Ｄ４よりも小さく、かつ、その距離の差Ｄ４−Ｄ３が前記接続すべき管の厚さの半分以上２倍以下の範囲となる関係を満たすような内面形状とされている管継手である。
【００２４】
その距離の差Ｄ４−Ｄ３が接続すべき管の厚さの半分未満であると、有効な改善効果を得ることができず、接続すべき管の厚さの２倍を超えると、管継手に管を接続するメカニズムに支障をきたすか、または内部に通す流体の通行を阻害するかのいずれかの問題が予想される。
【００２５】
本願の請求項４に記載の発明は、前記チーズ型の管継手が、前記管継手本体の主管軸方向の両端縁部に主管接続部が設けられ、主管軸と直交する枝管軸方向の端縁部に枝管接続部が設けられたものからなり、両主管接続部側の端縁部において、前記枝管接続部側の内面の曲率半径Ｒ３が枝管接続部から遠くなる側となる内面の曲率半径Ｒ４よりも大きく、その曲率半径の差Ｒ３−Ｒ４が前記主管接続部に接続すべき管の厚さの８倍以下の範囲となる関係を満たすような内面形状とされている請求項３に記載の管継手である。
【００２６】
その曲率半径の差Ｒ３−Ｒ４の下限は特にないが、有効な改善効果を得るためには、接続すべき管の肉厚の半分以上が好ましい。曲率半径の差Ｒ３−Ｒ４が主管接続部に接続すべき管の厚さの８倍を超えると、管継手に管を接続するメカニズムに支障をきたすか、または内部に通す流体の通行を阻害するかのいずれかの問題が予想される。
【００２７】
【作用】
本発明の管継手は、Ｌ字状エルボ型の管継手の管継手本体の両管接続部側の端縁部において、前記両管接続部の管軸を共に含む平面と交わる相対する内面部分間の距離Ｄ１が該平面から最も遠くなる相対する内面部分間の距離Ｄ２よりも小さく、かつ、その距離の差Ｄ２−Ｄ１が前記接続すべき管の厚さの半分以上２倍以下の範囲となる関係を満たすような内面形状とされているにより、管継手本体のもっとも歪んだ状態になり易い中央部の断面内面形状を、真円に近ずけることができるので、水力的応力が低減し、しかも、管継手部に管を接続するメカニズムに支障をきたすこともない。
【００２８】
更に、前記管継手本体の両管接続部側の端縁部において、曲折部の内側となる内面の曲率半径Ｒ１が曲折部の外側となる内面の曲率半径Ｒ２よりも大きく、その曲率半径の差Ｒ１−Ｒ２が前記接続すべき管の厚さの４倍以下の範囲となる関係を満たすような内面形状とされていることにより、管継手本体のもっとも歪んだ状態に易い中央部の断面内面形状を、その頂部付近の出っ張りが緩和された真円に近づけることができるので、一層、水力的応力が低減し、しかも管継手部に管を接続するメカニズムに支障をきたすこともない。
【００２９】
また、本発明の管継手は、チーズ型の管継手本体の各管接続部側の端縁部において、前記両管接続部の管軸を共に含む平面と交わる相対する内面部分間の距離Ｄ１が該平面から最も遠くなる相対する内面部分間の距離Ｄ２よりも小さく、かつ、その距離の差Ｄ２−Ｄ１が前記接続すべき管の厚さの半分以上２倍以下の範囲となる関係を満たすような内面形状とされていることにより、管継手本体のもっとも歪んだ状態になり易い中央部の断面内面形状を、真円に近ずけることができるので、水力的応力が低減し、しかも管継手部に管を接続するメカニズムに支障をきたすこともない。
【００３０】
更に、前記チーズ型の管継手が、前記管継手本体の主管軸方向の両端縁部に主管接続部が設けられ、主管軸と直交する枝管軸方向の端縁部に枝管接続部が設けられたものからなり、両主管接続部側の端縁部において、前記枝管接続部側の内面の曲率半径Ｒ３が枝管接続部から遠くなる側となる内面の曲率半径Ｒ４よりも大きく、その曲率半径の差Ｒ３−Ｒ４が前記主管接続部に接続すべき管の厚さの８倍以下の範囲となる関係を満たすような内面形状とされていることにより、管継手本体のもっとも歪んだ状態に易い中央部の断面内面形状を、その頂部付近の出っ張りが緩和された真円に近づけることができるので、一層、水力的応力が低減し、しかも管継手部に管を接続するメカニズムに支障をきたすこともない。
【００３１】
【発明の実施の形態】
以下、本発明の実施の形態を図面を参照して説明する。
図１〜６は本発明の一例の管継手の説明図である。
図１及び２に示すように、１は合成樹脂製のＬ字状エルボ型の管継手であって、曲折部１１１を有する管継手本体１１の両端部に、ＴＳ接続式の受口からなる管接続部１２，１３が設けられている。そして、管接続部１２，１３内に接着剤を介して断面円形の合成樹脂製の管を圧入することにより、内圧または外圧が作用する状態にて管を接続して配管を行うことができるようになっている。
【００３２】
この管継手１は、管継手本体１１の両管接続部１２，１３側の端縁部（図１の断面Ｂ，Ｂ）において、両管接続部１２，１３の管軸を共に含む平面と交わる相対する内面部分間の距離Ｄ１が該平面から最も遠くなる相対する内面部分間の距離Ｄ２よりも小さく、かつ、その距離の差Ｄ２−Ｄ１が接続すべき管の厚さの半分以上２倍以下の範囲となる関係を満たすような内面形状とされている（図３参照）。
【００３３】
また、管継手本体１１の両管接続部１２，１３側の端縁部において、曲折部１１１の最も内側となるＰ点の内面の曲率半径Ｒ１が曲折部１１１の最も外側となるＱ点の内面の曲率半径Ｒ２よりも大きく、その曲率半径の差Ｒ１−Ｒ２が接続すべき管の厚さの４倍以下の範囲となる関係を満たすような内面形状とされている（図３参照）。
【００３４】
そして、管継手本体１１の曲折部１１１の中央部（図１の４５°断面Ａ）における内面形状は、図４に示すような、頂部のＳ点付近の出っ張りが緩和された真円に近い内面形状となっている。これにより、水力的応力が低減すると考えられる。
【００３５】
この管継手１を製造するには、図５に示すような一対のダイス２１、２１からなる内型２が使用される。このダイス２１の曲折部形成部２１１の基端縁部（図６の断面Ｂ′）の外形が図３に示す形状と同じとされ、その先端縁部（図６のＡ′）の外形が図４に示す形状と同じとされている。
この一対のダイス２１、２１同士を、図５に示すようにその曲折部形成部２１１，２１１の先端面同士を突き合わせるようにして内型を形成し、図示しない外型との間で樹脂を成形することにより、上記の管継手１を製造することができる。
【００３６】
図７〜１３は本発明の別の例の管継手の説明図である。
図７及び８に示すように、３は合成樹脂製のチーズ型の管継手であって、断面Ｔ字型をなす管継手本体３１の主管軸方向の両端縁部に、ＴＳ接続式の受口からなる主管接続部３２，３３が設けられており、主管軸と直交する枝管軸方向の端縁部に枝管接続部３４が設けられている。主管接続部３２，３３及び枝管接続部３４には接着剤を介して断面円形の合成樹脂製の管を圧入することにより、内圧または外圧が作用する状態にて管を接続して配管することができるようになっている。
【００３７】
この管継手３は、管継手本体３１の両主管接続部３２，３３側の端縁部（図７の断面Ｄ，Ｄ）において、両主管接続部３２，３３の主管軸及び枝接続部の枝管軸を全て含む平面と交わる相対する内面部分間の距離Ｄ３が該平面と最も遠くなる相対する内面部分間の距離Ｄ４よりも小さく、かつ、その距離の差Ｄ４−Ｄ３が接続すべき管の厚さの半分以上２倍以下の範囲となる関係を満たすような内面形状とされている（図９参照）。
また、管継手本体３１の枝管接続部３４側の端縁部（図７の断面Ｅ）においても、上記と同様の関係を満たすような内面形状とされている。
【００３９】
また、管継手本体３１の両主管接続部３２，３３側の端縁部において、最も枝管接続部３４側となるＰ′，Ｐ′点の内面の曲率半径Ｒ３が枝管接続部３４から最も遠い側となるＱ′，Ｑ′点の内面の曲率半径Ｒ４よりも大きく、その曲率半径の差Ｒ３−Ｒ４が、主管接続部３２，３３に接続すべき管の厚さの８倍以下の範囲となる関係を満たすような内面形状とされている（図９参照）。
【００４０】
そして、管継手本体３１の最も枝管接続部３４側となるＰ′，Ｐ′点からその中心部のＨ点間を結ぶ面（図７の断面Ｇ，Ｇ）における内面形状は、図１１に示すような頂部のＳ′点付近の出っ張りが緩和された真円の上半分に近い内面形状となっている。また、管継手本体３１の中心部のＨ点とその底部中央部のＩ点を結ぶ面（図７の断面Ｊ）も真円の下半分に近い内面形状となっている。これにより、水力的応力が低減すると考えられる。
【００４１】
尚、管継手本体３１の両主管接続部３２，３３の基端部（図７の断面Ｆ，Ｆ）における内面形状は、両主管接続部３２，３３の主管軸及び枝接続部の枝管軸を含む平面と交わる相対する内面部分間の距離Ｄ５が該平面と最も遠くなる相対する内面部分間の距離Ｄ６よりも小さくなり、枝管接続部３４側の内面の曲率半径Ｒ５が枝管接続部３４から遠くなる側となる内面の曲率半径Ｒ６よりも大きくなるような楕円形となっている（図１０参照）。
管継手本体３１の両主管接続部３２，３３の先端部の内面形状は、真円となっている（図示せず）。
【００４２】
この管継手３を製造するには、図１３に示すような一対の主ダイス４１、４１と枝ダイス４２とからなる内型４が使用される。この主ダイス４１，４１として、管本体部形成部４１１，４１１の基端縁部（図１３の断面Ｄ′，Ｄ′）の外形が図９に示す形状と同じとされ、その先端縁部の上部傾斜面（図１３のＧ′面）の外形が図１１に示す形状と同じとされており、垂直面（図１３のＪ′面）の外形が図１２に示す形状と同じとされているものを用い、枝ダイス４２として、管本体部形成部４２１の先端部に、主ダイス４１，４１の先端縁部の上部傾斜面に対応する傾斜面が設けられたものを用いて、その管本体部形成部４１１，４１１，４２１の先端面同士を突き合わせるようにして内型を形成し、図示しない外型との間で樹脂を成形することにより、上記の管継手３を製造することができる。
【００４３】
図１４〜１７は本発明の別の例の管継手の説明図である。
図１４〜１７に示すように、５は合成樹脂製のチーズ型の管継手であって、図示するような形状と寸法関係となっていること以外は、図７〜１３を参照して説明したものと同じである（対応する図番と寸法符号を付してその詳細な説明は省略する）。
【００４４】
以下、本発明を実施例により説明する。
（実施例１）
図１〜４に示す管継手１であって、呼び径５０の塩化ビニル樹脂管（内径５１ｍｍ、外径６０ｍｍ）に対応するＴＳ接合式受口からなる管接続部１２，１３を管継手本体部１１の両端縁部に備えた、９０°エルボ型の塩化ビニル樹脂管継手（外径７０ｍｍ）を試作した。
【００４５】
この管継手１においては、管接続部１２，１３の管軸を含む平面と交わる相対する内面部分間の距離Ｄ１は５２ｍｍ、該平面から最も遠くなる相対する内面部分間の距離Ｄ２は５４ｍｍであった。従って、Ｄ１の方がＤ２よりも小さく、その距離の差Ｄ２−Ｄ１は２ｍｍであって、接続すべき管の厚さ４．５ｍｍの半分以上２倍以下（２．２５〜９ｍｍ）となっている。
【００４６】
また、この管継手１の管継手本体１１の管接続部１２側の端縁部における、曲折部１１１の最も内側となるＰ点の内面の曲率半径Ｒ１は２９．１６ｍｍ、曲折部１１１の最も外側となるＱ点の内面の曲率半径Ｒ２は２７ｍｍであって、Ｒ１の方がＲ２よりも大きく、その曲率半径の差Ｒ１−Ｒ２は２．１６ｍｍであって、接続すべき管の厚さ４．５ｍｍの４倍（１８ｍｍ）以下となっている。
【００４７】
呼び径５０の塩化ビニル樹脂管（内径５１ｍｍ、外径６０ｍｍ）を長さ２４０ｍｍに切断して、これを管継手１の両接続部１２，１３に接着剤を介して接着して配管し、この配管について、２３℃の水を用いて、脈動試験を行った。
この試験では、２．５秒周期、５０％デューティーで、０と２ＭＰａの２つの水圧値を往復する脈動水圧を管と接合した管継手の内面に与え、破壊するまでの回数を測定した。
その結果、サンプル数（ｎ）＝３にて行ったが、何れのサンプルについても、２０万回でも破壊しなかった。
【００４８】
（比較例１）
図１８〜２１に示す管継手１００であって、呼び径５０の塩化ビニル樹脂管（内径５１ｍｍ、外径６０ｍｍ）に対応するＴＳ接合式受口からなる管接続部１０２，１０３を管継手本体部１０１の両端縁部に備えた、９０°エルボ型の塩化ビニル樹脂管継手（外径７０ｍｍ）を試作した。
【００４９】
この管継手１０１においては、管接続部１０２，１０３の管軸を含む平面と交わる相対する内面部分間の距離ｄ１は５２ｍｍ、該平面から最も遠くなる相対する内面部分間の距離ｄ２も５２ｍｍであり、曲折部の最も内側となるｐ点の内面の曲率半径ｒ１は２６ｍｍ、曲折部１１１の最も外側となるｑ点の内面の曲率半径ｒ２も２６ｍｍであった。
【００５０】
この管継手１００を用いて、実施例１と同様の試験を行った。
その結果、サンプル数（ｎ）＝３における破壊までの回数は、４８７３５回、３４８２６回、５９０３７回で、その平均は４７５３３であり、破壊部位は何れも、図２４にｃとして示す部分であった。
【００５１】
（実施例２）
図７〜１２に示す管継手３であって、呼び径５０の塩化ビニル樹脂管（内径５１ｍｍ、外径６０ｍｍ）に対応するＴＳ接合式受口からなる主管接続部３２，３３を管継手本体３１の両端縁部に備え、呼び径５０の塩化ビニル樹脂管（内径５１ｍｍ、外径６０ｍｍ）に対応するＴＳ接合式受口からなる枝管接続部３４を備えたチーズ型の塩化ビニル樹脂管継手（外径７０ｍｍ）を試作した。
【００５２】
この管継手３は、管継手本体３１の両主管接続部３２，３３側の端縁部（図７の断面Ｄ，Ｄ）において、両主管接続部３２，３３の主管軸及び枝接続部の枝管軸を含む平面と交わる相対する内面部分間の距離Ｄ３が５２ｍｍであり、該平面と最も遠くなる相対する内面部分間の距離Ｄ４が５７ｍｍであって、Ｄ３の方がＤ４よりも小さくなっており、その距離の差Ｄ４−Ｄ３は５ｍｍであって、接続すべき管の厚さ４．５ｍｍの半分以上２倍以下（２．２５〜９ｍｍ）の範囲となっていた。
【００５３】
また、この管継手３は、管継手本体３１の両主管接続部３２，３３側の端縁部において、枝管接続部３４側の内面の曲率半径Ｒ３が３８．６８ｍｍ、枝管接続部３４から遠くなる側となる内面の曲率半径Ｒ４が２６．２０ｍｍであって、Ｒ３の方がＲ４よりも大きく、その曲率半径の差Ｒ３−Ｒ４は２．４８ｍｍであって、両主管接続部３２，３３に接続すべき管の厚さ（４．５ｍｍ）の８倍（３６ｍｍ）以下の範囲となっていた。
【００５４】
この管継手３を用いて、実施例１と同様の試験を行った。
その結果、サンプル数（ｎ）＝３にて行ったが、何れのサンプルについても、２０万回でも破壊しなかった。
【００５５】
（実施例３）
図１４〜１７に示す管継手５であって、呼び径５０の塩化ビニル樹脂管（内径５１ｍｍ、外径６０ｍｍ）に対応するＴＳ接合式受口からなる主管接続部５２，５３を管継手本体５１の両端縁部に備え、呼び径５０の塩化ビニル樹脂管（内径５１ｍｍ、外径６０ｍｍ）に対応するＴＳ接合式受口からなる枝管接続部５４を備えたチーズ型の塩化ビニル樹脂管継手（外径７１ｍｍ）を試作した。
【００５６】
この管継手５は、管継手本体５１の両主管接続部５２，５３側の端縁部（図１４の断面Ｄ，Ｄ）において、両主管接続部５２，５３の主管軸及び枝接続部の枝管軸を含む平面と交わる相対する内面部分間の距離Ｄ７が５２ｍｍであり、該平面と最も遠くなる相対する内面部分間の距離Ｄ８が５７ｍｍであって、Ｄ７の方がＤ８よりも小さく、かつ、その距離の差Ｄ８−Ｄ７は５ｍｍ）であって、接続すべき管の厚さ（４．５ｍｍ）の半分以上２倍以下（２．２５〜９ｍｍ）の範囲となる関係を満たすような内面形状となっていた。
【００５７】
また、この管継手５の管継手本体５１の両主管接続部５２，５３側の端縁部において、枝管接続部５４側の内面の曲率半径Ｒ７が４６．１３ｍｍ、枝管接続部５４から遠くなる側となる内面の曲率半径Ｒ８が２５．７５であって、Ｒ７の方がＲ８よりも大きく、その曲率半径の差Ｒ７−Ｒ８は２０．３８ｍｍであって、両主管接続部５２，５３に接続すべき管の厚さ（４．５ｍｍ）の８倍以下（３６ｍｍ）の範囲となる関係を満たすような内面形状となっていた。
【００５８】
この管継手５を用いて、実施例１と同様の試験を行った。
その結果、サンプル数（ｎ）＝３にて行ったが、何れのサンプルについても、２０万回でも破壊しなかった。
【００５９】
（比較例２）
図２５〜２８に示す管継手５であって、呼び径５０の塩化ビニル樹脂管（内径５１ｍｍ、外径６０ｍｍ）に対応するＴＳ接合式受口からなる主管接続部３０２，３０３を管継手本体３０１の両端縁部に備え、呼び径５０の塩化ビニル樹脂管（内径５１ｍｍ、外径６０ｍｍ）に対応するＴＳ接合式受口からなる枝管接続部３０４を備えたチーズ型の塩化ビニル樹脂管継手（外径７１ｍｍ）を試作した。
この管継手３００を用いて、実施例１と同様の試験を行った。
その結果、サンプル数（ｎ）＝３における破壊までの回数は、１３８７５回、２４３６７回、１９２０８回で、その平均は１９１５０であり、破壊部位は何れも、図３０にｇとして示す部分であった。
【００６０】
【発明の効果】
本発明の管継手は、成形方法に固有の制約の下に、水道管等、内部に正の圧力がかかる配管を急角度にてＬ字状やＴ字状に曲折するように配管する際に、内外圧差、特にその使用中の圧力変動に伴って継手材料に発生する応力の最大値を低減し、こうした応力に伴って長期的に進行する破壊を低減するように、力学的耐性が向上している。
【図面の簡単な説明】
【図１】本発明の管継手の一例のＬ字状エルボ型の管継手を示す断面図である。
【図２】図１に示す管継手の右側面図である。
【図３】図１の断面Ｂにおける内面形状である。
【図４】図１の断面Ａにおける内面形状である。
【図５】図１及び２に示す管継手の製造に用いられる内型を示す正面図である。
【図６】図５に示す内型の一方のダイスを示す正面図である。
【図７】本発明の管継手の一例のチーズ型の管継手を示す断面図である。
【図８】図７に示す管継手の右側面図である。
【図９】図７の断面Ｄにおける内面形状である。
【図１０】図７の断面Ｆにおける内面形状である。
【図１１】図７の断面Ｇにおける内面形状である。
【図１２】図７の断面Ｊにおける内面形状である。
【図１３】図７及び８に示す管継手の製造に用いられる内型を示す正面図である。
【図１４】本発明の管継手の別の例のチーズ型の管継手を示す断面図である。
【図１５】部１４のＫ−Ｋ線に沿う断面図である。
【図１６】図１４の断面Ｄにおける内面形状である。
【図１７】図１４の断面Ｅにおける内面形状である。
【図１８】従来のエルボ型の管継手の一例の断面図である。
【図１９】図１８の右側面図である。
【図２０】図１８の断面ｂにおける内面形状である。
【図２１】図１８の断面ａにおける内面形状である。
【図２２】図１８及び１９に示す管継手の製造に用いられる内型を示す正面図である。
【図２３】図２２に示す内型の一方のダイスを示す正面図である。
【図２４】図１８及び１９に示す管継手の破壊状態を示す斜視図である。
【図２５】従来のチーズ型の管継手の一例の断面図である。
【図２６】図２５の右側面図である。
【図２７】図２５の断面ｄにおける内面形状である。
【図２８】図２５の断面ｆにおける内面形状である。
【図２９】図２５及び２６に示す管継手を製造するのに用いられる内型を示す正面図である。
【図３０】図２５及び２６に示す管継手の破壊状態を示す斜視図である。
【符号の説明】
１，３，５管継手
２，４内型
１１，３１，５１管継手本体
１２，１３管接続部
３２，３３主管接続部
３４枝管接続部
１１１曲折部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an elbow-type or cheese-type pipe joint that is suitably used for pipes such as water pipes that are bent at a steep angle.
[0002]
[Prior art]
Conventionally, as a method of connecting a pipe made of synthetic resin and a pipe joint, there are various connection methods such as TS connection, welding connection, fusion connection, mechanical connection, etc., which are appropriately selected and used depending on the application and purpose. It has been.
Regardless of the connection method, the outer shape of the pipe joint is appropriately determined to satisfy the conflicting requirements of the strength required to bear the stress caused by hydraulic pressure and the saving of construction space and materials. ing.
[0003]
On the other hand, the shape of the inner surface of the pipe joint is appropriately determined so as to satisfy the conflicting demands for strength against hydraulic stress and ensuring the ease of passage of the fluid flowing inside. However, in practice, a dimension substantially equal to the inner diameter of the pipe is often set as the minimum dimension of the inner diameter of the pipe joint, and standards such as the JIS standard are generally such (see Non-Patent Documents 1 and 2).
[0004]
Therefore, in an actual pipe joint product, the inner surface shape of the portion close to the pipe connection portion of the pipe joint main body is usually a circle close to this minimum dimension. This is because the maximum shape of the stress generated in the pipe joint material by hydraulic pressure can be reduced most, in addition to the shape of the circle being the most basic geometric shape for composing the shape, It is considered to be based on a natural idea of making the inner diameter as small as possible and thereby ensuring the wall thickness as large as possible.
[0005]
Next, the above contents will be described with reference to FIGS. 18 to 24 by taking a conventional elbow type pipe joint as an example.
As shown in FIGS. 18 and 19, this elbow type pipe joint 100 has a bent portion at the center. Pipe fitting body Pipe connecting portions 102 and 103 are provided at both ends of 101.
Pipe fitting body The inner surface shape of both end edges (sections b and b in FIG. 18) on both pipe connection portions 102 and 103 side of 101 is a perfect circle as shown in FIGS.
Therefore, the distance d1 between the opposing inner surface portions intersecting the plane including the tube axis of both the pipe connecting portions 102 and 103 is equal to the distance d2 between the opposing inner surface portions farthest from the plane. Further, at both edges, the radius of curvature r1 of the inner surface that is the inner side of the bent portion is equal to the radius of curvature r2 of the inner surface that is the outer side of the bent portion.
[0006]
Accordingly, the pipe joint 100 has an inner shape at the center (45 ° cross section a in FIG. 18) of the bent portion of the pipe joint main body 101 as shown in FIG. The top s portion is sharp and has a so-called rice ball-shaped distorted shape with protrusions on both sides of the lower portion.
[0007]
That is, the upper half of the region of the end face when the cylindrical body extending from the end edges b, b on both pipe connecting portions 102, 103 side to the central portion a of the bent portion of the pipe joint body 101 is cut at an angle of 45 °. Appears as a shape, which is the same shape as the upper part of a vertically long ellipse with only the vertical axis extended by √2 times, and the lower half of the area forms a straight torus with a curve that matches the curve. Because.
[0008]
That is, in order to manufacture the pipe joint 100, an inner mold 200 including a pair of dies 201 and 201 as shown in FIG. 22 is used. As shown in FIG. 23, the outer shape of the bent portion forming portion 211 of the die 201 is cut at an angle of 45 ° with a cylindrical body whose upper half is a cylinder and whose lower half is curved. Since it is normal to be in this state, the inner surface shape of the bent portion of the pipe joint main body 101 of the pipe joint 100 to be molded is determined as described above.
[0009]
As a result, when a positive hydrostatic pressure is repeatedly applied to the inside of the pipe joint 100 in the pipe in which the pipe is connected using the pipe joint 100, as shown in FIG. The pulling force in the direction perpendicular to both axes of the connecting portions 102 and 103 works, so that the crack generated on the inner surface grows so as to penetrate to the outer surface, and the scratch shown as c in the figure enters. Will happen.
This is especially true for thin products, as well as the so-called membrane stress that pulls the wall with internal pressure, as well as the force that bends the tube wall, which is closely related to the slight entry and exit of the shape. It is thought that it is connected with big stress.
[0010]
Furthermore, the above-mentioned content is demonstrated with reference to FIGS. 25-30 by making the conventional cheese type pipe joint into an example.
As shown in FIGS. 25 and 26, the cheese-type pipe joint 300 has a T-shaped cross section. Pipe fitting body Main pipe connection portions 302 and 303 are provided at both end edges in the main pipe axis direction 301, and branch pipe connection portions 304 are provided at end edges in the branch pipe axis direction orthogonal to the main pipe axis.
In this pipe joint 300, Pipe fitting body The inner surface shape of the edge 301 (sections d and d in FIG. 25) on the main pipe connection portions 302 and 303 side of 301 is a perfect circle having a diameter d3 as shown in FIG. 27, and the end on the branch pipe connection portion 304 side. The inner surface shape at the edge (section e in FIG. 25) is also a perfect circle.
[0011]
Accordingly, the pipe joint 300 has a vertically long oval shape at the boundary part (45 ° cross section f, f in FIG. 25) between the main pipe connection parts 302 and 303 of the pipe joint main body 301 and the branch pipe connection part 304. The top half of the shape is sharp and the top t is pointed.
[0012]
This is because the upper half of the upper half of the cylindrical body extending from the end edge (cross section d, d in FIG. 25) on the both main pipe connecting portions 302 and 303 side to the center of the bent portion of the pipe joint body 101 is inclined 45. This is because it becomes the same shape as the upper part of the vertically long ellipse, which appears as the shape of the end face when cut at 0 °, with only the vertical axis extended by √2.
[0013]
That is, in order to manufacture this pipe joint 300, an inner mold 400 including main pipe forming dies 401 and 401 and a branch pipe forming die 402 as shown in FIG. 29 is used.
Among these, the outer shape of the bent portion forming portion 411 of the main pipe forming die 401 is cut at an oblique angle of 45 ° with the upper half of the tip end side being a cylindrical body and the lower half being a cylindrical body in accordance with the bending. However, it is common to use the one in which the lower half is cut vertically, and the outer shape of the branch pipe forming die 402 is such that the front end surface thereof corresponds to the front end surface of the main pipe forming dies 401, 401. Therefore, the inner surface shape of the boundary portion between the main pipe connecting portions 302 and 303 of the pipe joint 300 to be molded and the branch pipe connecting portion 304 is determined as described above.
[0014]
As a result, when a positive hydrostatic pressure is repeatedly applied to the inside of the pipe joint 300 in the pipe in which the pipe is connected using the pipe joint 300, as shown in FIG. A pulling force acts in a direction perpendicular to the main axis of the connection portions 302 and 303 and the branch tube axis of the branch pipe connection portion 304, and a crack generated on the inner surface grows so as to penetrate to the outer surface, and is indicated as g in the figure. It becomes an inconvenient situation that such a wound enters.
This is especially true for thin products, as well as the so-called membrane stress that pulls the wall with internal pressure, as well as the force that bends the tube wall, which is closely related to the slight entry and exit of the shape. It is thought that it is connected with big stress.
[0015]
[Non-Patent Document 1]
JIS K 6742
[Non-Patent Document 2]
JIS K 6743
[0016]
[Problems to be solved by the invention]
In view of the conventional problems as described above, as a measure against the stress acting on the pipe joint due to the hydraulic pressure, the thickness is not increased only, but depending on the location, the thickness is rather decreased. An object of the present invention is to provide a pipe joint product that is excellent in strength as compared with the case where meat is accumulated in the place while saving material.
[0017]
Further, the present invention is premised on molding using a generally reused mold such as injection molding or compression molding as a technical means for forming the inner and outer surfaces of a product.
In general, molds that are reused consist of a part called a cavity that forms the outer surface and a part called a core that forms the inner surface for shapes such as pipe joints. The above demand difficulty is high. This is because it is necessary to have a shape or mechanism that allows the product to be safely pulled out from the narrow inner surface without breaking the product after being subjected to molding of a single product.
[0018]
The present invention provides a pressure difference between the inside and outside of the pipe, such as a water pipe, in which a positive pressure is internally bent so as to be bent at a steep angle, particularly the pressure fluctuation during use, under the restrictions inherent to the molding method. The elbow-type or cheese-type pipe joint with improved mechanical resistance is provided in order to reduce the maximum value of stress generated in the joint material and reduce long-term fracture caused by such stress. For the purpose.
[0019]
[Means for Solving the Problems]
The invention according to claim 1 of the present application is a pipe joint book having a bent portion. the body's An L-shaped elbow-shaped pipe joint provided with a pipe connecting part capable of connecting a pipe having a circular cross section at both end edges, wherein the both ends of the pipe joint main body at both pipe connecting part side The distance D1 between the opposite inner surface portions intersecting with the plane including both the tube axes of the tube connecting portions is smaller than the distance D2 between the opposite inner surface portions farthest from the plane, and the difference D2-D1 between the distances is D2−D1. It is a pipe joint having an inner surface shape that satisfies a relationship that is in a range of not less than half and not more than twice the thickness of a pipe to be connected.
[0020]
If the distance difference D2-D1 is less than half of the thickness of the pipe to be connected, an effective improvement effect cannot be obtained, and if it exceeds twice the thickness of the pipe to be connected, Problems are anticipated that either hinder the mechanism of connecting the tubes or block the passage of fluid through the interior.
[0021]
The invention according to claim 2 of the present application is such that, at the end edge portion of the pipe joint body on the both pipe connecting portions side, the radius of curvature R1 of the inner surface that becomes the inner side of the bent portion is the radius of curvature R2 of the inner surface that becomes the outer side of the bent portion. 2. The pipe joint according to claim 1, wherein the inner surface shape is such that the difference in radius of curvature R 1 -R 2 is larger than the thickness of the pipe to be connected and is less than four times the thickness of the pipe to be connected. .
[0022]
There is no particular lower limit for the difference in radius of curvature R1-R2, but in order to obtain an effective improvement effect, it is preferable that the thickness of the pipe to be connected be at least half the wall thickness. If the difference in radius of curvature R1-R2 exceeds four times the thickness of the pipe to be connected, either the mechanism for connecting the pipe to the pipe joint will be hindered or the passage of fluid through the inside will be obstructed The problem is expected.
[0023]
The invention according to claim 3 of the present application is a pipe joint book having a T-shaped cross section. the body's A cheese-type pipe joint provided with a pipe connecting part capable of connecting a pipe having a circular cross section at each end edge part, and at the end edge part on the side of each pipe connecting part of the pipe joint body, each pipe connection The distance D3 between the opposing inner surface portions intersecting with the plane including all the tube axes is smaller than the distance D4 between the opposing inner surface portions farthest from the plane, and the difference D4-D3 between the distances is connected. It is a pipe joint having an inner surface shape that satisfies a relationship that is in a range of not less than half and not more than twice the thickness of the power pipe.
[0024]
Difference in distance D4- D3 If the thickness is less than half of the thickness of the pipe to be connected, an effective improvement effect cannot be obtained, and if it exceeds twice the thickness of the pipe to be connected, the mechanism for connecting the pipe to the pipe joint is impaired. Problems are anticipated that either impede or block the passage of fluid through the interior.
[0025]
In the invention according to claim 4 of the present application, the cheese-type pipe joint is provided with a main pipe connection portion at both end edges in the main pipe axis direction of the pipe joint body, and the end in the branch pipe axis direction orthogonal to the main pipe axis. An inner surface having a branch pipe connecting portion provided at the edge, and an end radius on both main pipe connecting portions side where the radius of curvature R3 of the inner surface on the branch pipe connecting portion side is far from the branch pipe connecting portion. The radius of curvature R4 is larger than the radius of curvature R4, and the inner radius is such that the difference in radius of curvature R3-R4 satisfies a relationship that is less than eight times the thickness of the pipe to be connected to the main pipe connecting portion. 3. The pipe joint according to 3.
[0026]
There is no particular lower limit for the difference in radius of curvature R3-R4, but in order to obtain an effective improvement effect, it is preferable that the thickness is not less than half of the thickness of the pipe to be connected. If the difference in radius of curvature R3-R4 exceeds 8 times the thickness of the pipe to be connected to the main pipe connection, the mechanism for connecting the pipe to the pipe joint will be hindered or the passage of fluid through the inside will be obstructed. One of the problems is expected.
[0027]
[Action]
In the pipe joint of the present invention, an L-shaped elbow-type pipe joint has an inner edge portion that intersects with a plane including both the pipe axes of the pipe joint portions at the end edges on the pipe joint body side of the pipe joint body. The distance D1 is smaller than the distance D2 between the opposing inner surface portions farthest from the plane, and the distance difference D2-D1 is in the range of not less than half and not more than twice the thickness of the pipe to be connected. The inner surface shape that satisfies the relationship allows the cross-section inner surface shape of the central part, which is most likely to be distorted, to be close to a perfect circle, thereby reducing hydraulic stress, Moreover, the mechanism for connecting the pipe to the pipe joint Hindrance I will never come.
[0028]
Further, at the edge of the pipe joint body on the both pipe connecting portions side, the radius of curvature R1 of the inner surface that is the inner side of the bent portion is larger than the radius of curvature R2 of the inner surface that is the outer side of the bent portion, and the difference in the radius of curvature. By making the inner surface shape so as to satisfy the relationship in which R1-R2 is less than or equal to four times the thickness of the pipe to be connected, the cross-sectional inner surface shape of the central portion that is most easily distorted of the pipe joint body Can be brought closer to a perfect circle where the protrusion near the top is relaxed, the hydraulic stress is further reduced and the mechanism for connecting the pipe to the pipe joint is Hindrance I will never come.
[0029]
In the pipe joint of the present invention, the distance D1 between opposing inner surface portions intersecting a plane including both the pipe axes of the pipe connection parts at the end edge part on the side of each pipe connection part of the cheese-type pipe joint body. The distance D2 is smaller than the distance D2 between the opposed inner surface portions farthest from the plane, and the distance difference D2-D1 satisfies a relationship that is in the range of not less than half and not more than twice the thickness of the pipe to be connected. Since the inner surface shape of the pipe joint body can be closer to a perfect circle, the hydraulic stress is reduced, and the pipe joint body has the most distorted state. To the mechanism to connect the pipe to the part Hindrance I will never come.
[0030]
Further, the cheese-type pipe joint is provided with a main pipe connection portion at both end edges in the main pipe axis direction of the pipe joint body, and a branch pipe connection portion is provided at an end edge portion in the branch pipe axis direction orthogonal to the main pipe axis. The radius of curvature R3 of the inner surface on the side of the branch pipe connecting portion is larger than the radius of curvature R4 of the inner surface on the side farther from the branch pipe connecting portion at the end edges on both main pipe connecting portions side, The innermost shape satisfying the relationship in which the difference in curvature radius R3-R4 is in the range of 8 times or less the thickness of the pipe to be connected to the main pipe connection portion, the pipe body is most distorted. The inner cross-sectional shape of the central part, which is easy to handle, can be approximated to a perfect circle with a bulged protrusion near the top, further reducing the hydraulic stress and providing a mechanism for connecting the pipe to the pipe joint. Hindrance I will never come.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1-6 is explanatory drawing of the pipe joint of an example of this invention.
As shown in FIGS. 1 and 2, reference numeral 1 denotes an L-shaped elbow pipe joint made of synthetic resin, which has a bent portion 111. Pipe fitting body 11 are provided with pipe connection parts 12 and 13 comprising TS connection type receiving ports. And by inserting a pipe made of a synthetic resin having a circular cross section into the pipe connecting portions 12 and 13 through an adhesive, the pipe can be connected and piped in a state where the internal pressure or the external pressure acts. It has become.
[0032]
The pipe joint 1 intersects with a plane including both the pipe axes of the pipe connection portions 12 and 13 at the end edges (sections B and B in FIG. 1) of the pipe joint main body 11 on the both pipe connection portions 12 and 13 side. The distance D1 between the opposing inner surface portions is smaller than the distance D2 between the opposing inner surface portions farthest from the plane, and the distance difference D2-D1 is not less than half and not more than twice the thickness of the pipe to be connected. It is set as the inner surface shape which satisfy | fills the relationship used as this range (refer FIG. 3).
[0033]
Further, at the end edges of the pipe joint main body 11 on the both pipe connecting portions 12 and 13 side, the inner radius of the point Q where the radius of curvature R1 of the inner surface of the point P which is the innermost side of the bent portion 111 is the outermost side of the bent portion 111. The inner surface shape is such that the difference R1-R2 between the curvature radii is less than four times the thickness of the pipe to be connected (see FIG. 3).
[0034]
And the inner surface shape in the center part (45-degree cross section A of FIG. 1) of the bending part 111 of the pipe joint main body 11 is an inner surface close | similar to the perfect circle where the protrusion of the S vicinity of the top part was eased as shown in FIG. It has a shape. This is thought to reduce hydraulic stress.
[0035]
In order to manufacture this pipe joint 1, an inner mold 2 comprising a pair of dies 21, 21 as shown in FIG. 5 is used. The outer shape of the base edge portion (section B ′ in FIG. 6) of the bent portion forming portion 211 of the die 21 is the same as the shape shown in FIG. 3, and the outer shape of the tip edge portion (A ′ in FIG. 6) is shown in the figure. The shape is the same as that shown in FIG.
As shown in FIG. 5, the pair of dies 21 and 21 is formed with an inner mold so that the end surfaces of the bent portion forming portions 211 and 211 are abutted with each other, and resin is placed between the pair of dies 21 and 21 with an outer mold (not shown). The pipe joint 1 can be manufactured by molding.
[0036]
7-13 is explanatory drawing of the pipe joint of another example of this invention.
As shown in FIGS. 7 and 8, 3 is a cheese-type pipe joint made of synthetic resin, which has a T-shaped cross section. Pipe fitting body The main pipe connection parts 32 and 33 which consist of TS connection type receptacles are provided in the both-ends edge part of the 31 main pipe axis direction, and the branch pipe connection part 34 is provided in the edge part of the branch pipe axis direction orthogonal to a main pipe axis. Is provided. A pipe made of synthetic resin having a circular cross section is press-fitted into the main pipe connecting parts 32 and 33 and the branch pipe connecting part 34 with an adhesive, so that the pipes are connected and piped in a state where an internal pressure or an external pressure acts. Can be done.
[0037]
This pipe joint 3 is connected to the main pipe shafts of both the main pipe connection parts 32 and 33 and branches of the branch connection parts at the end edges (sections D and D in FIG. 7) of the pipe joint body 31 on the both main pipe connection parts 32 and 33 side. The distance D3 between the opposing inner surface portions intersecting the plane including all the tube axes is smaller than the distance D4 between the opposing inner surface portions farthest from the plane, and the difference D4-D3 of the distances of the tubes to be connected It is made into the inner surface shape which satisfy | fills the relationship used as the range more than half and 2 times or less of thickness (refer FIG. 9).
Further, the end edge portion (section E in FIG. 7) of the pipe joint body 31 on the side of the branch pipe connecting portion 34 has an inner surface shape that satisfies the same relationship as described above.
[0039]
Further, the radius of curvature R3 of the inner surface at the points P ′ and P ′ closest to the branch pipe connection portion 34 at the end edges on the both main pipe connection portions 32 and 33 side of the pipe joint body 31 is the most from the branch pipe connection portion 34. The radius of curvature R4 is larger than the radius of curvature R4 of the inner surface of the Q ′ and Q ′ points on the far side, and the radius of curvature R3-R4 is less than 8 times the thickness of the pipe to be connected to the main pipe connecting portions 32 and 33. The inner surface shape satisfies the following relationship (see FIG. 9).
[0040]
And the inner surface shape in the surface (section G, G of FIG. 7) which connects between the P ', P' point which becomes the branch pipe connection part 34 side of the pipe joint main body 31 and the H point of the center part is shown in FIG. As shown in the figure, it has an inner surface shape close to the upper half of a perfect circle in which the bulge in the vicinity of the S ′ point at the top is relaxed. Further, the surface (section J in FIG. 7) connecting the H point at the center of the pipe joint body 31 and the I point at the center of the bottom has an inner surface shape close to the lower half of the perfect circle. This is thought to reduce hydraulic stress.
[0041]
In addition, the inner surface shape in the base end part (section F, F of FIG. 7) of both the main pipe connection parts 32 and 33 of the pipe joint main body 31 is the main pipe axis of both the main pipe connection parts 32 and 33, and the branch pipe axis of the branch connection part. The distance D5 between the opposite inner surface portions intersecting the plane including the distance D5 is smaller than the distance D6 between the opposite inner surface portions farthest from the plane, and the radius of curvature R5 of the inner surface on the branch pipe connecting portion 34 side is the branch pipe connecting portion. It has an elliptical shape that is larger than the radius of curvature R6 of the inner surface on the side far from 34 (see FIG. 10).
The inner surface shape of the tip end portions of both main pipe connecting portions 32 and 33 of the pipe joint body 31 is a perfect circle (not shown).
[0042]
In order to manufacture the pipe joint 3, an inner mold 4 including a pair of main dies 41 and 41 and a branch die 42 as shown in FIG. 13 is used. As this main die 41, 41 ,tube The outer shapes of the base end edge portions (sections D ′ and D ′ in FIG. 13) of the main body portion forming portions 411 and 411 are the same as those shown in FIG. 9, and the upper inclined surface (G ′ in FIG. The outer shape of the surface) is the same as the shape shown in FIG. 11, and the outer shape of the vertical surface (the J ′ surface in FIG. 13) is the same as the shape shown in FIG. The pipe body part forming part 421 is provided with an inclined surface corresponding to the upper inclined surface of the tip edge part of the main dies 41, 41 at the tip part of the main die 41, 41. The pipe joint 3 can be manufactured by forming an inner mold so that the end faces are butted and molding a resin with an outer mold (not shown).
[0043]
14-17 is explanatory drawing of the pipe joint of another example of this invention.
As shown in FIGS. 14 to 17, 5 is a synthetic resin cheese-shaped pipe joint, which has been described with reference to FIGS. (The corresponding figure numbers and dimensional codes are assigned and detailed description thereof is omitted).
[0044]
Hereinafter, the present invention will be described with reference to examples.
Example 1
1 to 4, the pipe connection parts 12 and 13 comprising TS joint type receptacles corresponding to a vinyl chloride resin pipe (inner diameter: 51 mm, outer diameter: 60 mm) having a nominal diameter of 50 are connected to the pipe joint main body. A 90 ° elbow-type vinyl chloride resin pipe joint (outer diameter: 70 mm) provided at both end edges of No. 11 was manufactured as a prototype.
[0045]
In this pipe joint 1, the distance D1 between the opposing inner surface portions intersecting with the plane including the tube axis of the pipe connecting portions 12 and 13 is 52 mm, and the distance D2 between the opposing inner surface portions farthest from the plane is 54 mm. It was. Therefore, D1 is smaller than D2, and the distance difference D2-D1 is 2 mm, which is not less than half and not more than twice the thickness of the pipe to be connected 4.5 mm (2.25 to 9 mm). Yes.
[0046]
Further, the radius of curvature R1 of the inner surface of point P, which is the innermost side of the bent portion 111, is 29.16 mm and the outermost side of the bent portion 111 at the end of the pipe joint body 11 of the pipe joint 1 on the pipe connecting portion 12 side. The radius of curvature R2 of the inner surface of the point Q becomes 27 mm, R1 is larger than R2, the difference in radius of curvature R1-R2 is 2.16 mm, and the thickness of the pipe to be connected. It is 4 times (18 mm) or less of 5 mm.
[0047]
A polyvinyl chloride resin pipe (inner diameter: 51 mm, outer diameter: 60 mm) having a nominal diameter of 50 is cut into a length of 240 mm, and this is bonded to both connecting portions 12 and 13 of the pipe joint 1 with an adhesive and piped. About piping, the pulsation test was done using 23 degreeC water.
In this test, pulsating water pressure reciprocating two water pressure values of 0 and 2 MPa was applied to the inner surface of the pipe joint joined to the pipe at a cycle of 2.5 seconds and 50% duty, and the number of times until the pipe joint was broken was measured.
as a result, Number of samples (n) = 3, but none of the samples was broken even after 200,000 times.
[0048]
(Comparative Example 1)
18 to 21 is a pipe joint 100, in which pipe connection parts 102 and 103 each comprising a TS-joint receiving port corresponding to a vinyl chloride resin pipe having a nominal diameter of 50 (inner diameter 51 mm, outer diameter 60 mm) A 90 ° elbow-type vinyl chloride resin pipe joint (outer diameter: 70 mm) provided at both edge portions of 101 was made as a prototype.
[0049]
In this pipe joint 101, a pipe connecting portion 102, 103 The distance d1 between the opposing inner surface portions intersecting with the plane including the tube axis is 52 mm, and the distance between the opposing inner surface portions furthest from the plane d2 52 mm, the radius of curvature r1 of the inner surface of the point p which is the innermost side of the bent portion is 26 mm, and the radius of curvature r2 of the inner surface of the point q which is the outermost side of the bent portion 111 is also 26 mm.
[0050]
Using this pipe joint 100, the same test as in Example 1 was performed.
as a result, Number of samples (n) The number of times until destruction at = 3 was 48735, 34826, and 59037, and the average was 47533, and all the destruction sites were portions indicated by c in FIG.
[0051]
(Example 2)
The pipe joint 3 shown in FIGS. 7 to 12 is provided with main pipe connecting portions 32 and 33 each having a TS joint type receptacle corresponding to a vinyl chloride resin pipe having a nominal diameter of 50 (inner diameter 51 mm, outer diameter 60 mm). Pipe fitting body A cheese-type vinyl chloride resin pipe fitting provided with branch pipe connection portions 34 comprising TS junction type receptacles provided at both end edges of 31 and corresponding to a vinyl chloride resin pipe having a nominal diameter of 50 (inner diameter 51 mm, outer diameter 60 mm) (Outer diameter 70 mm) was made as a prototype.
[0052]
This pipe joint 3 is connected to the main pipe shafts of both the main pipe connection parts 32 and 33 and branches of the branch connection parts at the end edges (sections D and D in FIG. 7) of the pipe joint body 31 on the both main pipe connection parts 32 and 33 side. The distance D3 between the opposing inner surface portions intersecting the plane including the tube axis is 52 mm, the distance D4 between the opposing inner surface portions farthest from the plane is 57 mm, and D3 is smaller than D4. The distance difference D4-D3 was 5 mm, which was in the range of not less than half and not more than twice the thickness of the tube to be connected 4.5 mm (2.25 to 9 mm).
[0053]
Further, the pipe joint 3 has a radius of curvature R3 of the inner surface on the side of the branch pipe connection part 34 at the end edge part on the both main pipe connection parts 32 and 33 side of the pipe joint body 31 of 38.68 mm. The radius of curvature R4 of the inner surface on the far side is 26.20 mm, R3 is larger than R4, the difference in radius of curvature R3-R4 is 2.48 mm, and both main pipe connecting portions 32, 33 It was in the range of 8 times (36 mm) or less of the thickness (4.5 mm) of the tube to be connected to.
[0054]
Using this pipe joint 3, the same test as in Example 1 was performed.
as a result, Number of samples (n) = 3, but none of the samples was broken even after 200,000 times.
[0055]
(Example 3)
14 to 17, main pipe connecting portions 52 and 53 each comprising a TS joint type receptacle corresponding to a vinyl chloride resin pipe having a nominal diameter of 50 (inner diameter 51 mm, outer diameter 60 mm). Pipe fitting body A cheese-type vinyl chloride resin pipe fitting provided with branch pipe connection portions 54 provided at TS both ends of 51 and corresponding to a vinyl chloride resin pipe (inner diameter 51 mm, outer diameter 60 mm) having a nominal diameter of 50 (Outer diameter 71 mm) was made as a prototype.
[0056]
This pipe joint 5 is composed of the main pipe shafts of both the main pipe connection parts 52 and 53 and the branches of the branch connection parts at the end edges (sections D and D in FIG. 14) on the both main pipe connection parts 52 and 53 side of the pipe joint main body 51. The distance D7 between the opposing inner surface portions intersecting the plane including the tube axis is 52 mm, the distance D8 between the opposing inner surface portions farthest from the plane is 57 mm, and D7 is smaller than D8, and , That distance difference D8 − D7 Is 5 mm), and the inner surface has a shape satisfying a relationship that is in the range of not less than half and not more than twice the thickness of the tube to be connected (4.5 mm) (2.25 to 9 mm).
[0057]
Further, the radius of curvature of the inner surface on the side of the branch pipe connection part 54 at the end edge part on the both main pipe connection parts 52 and 53 side of the pipe joint body 51 of the pipe joint 5 R7 46.13 mm, radius of curvature of the inner surface on the side farther from the branch pipe connection 54 R8 Is 25.75, R7 Is better R8 Greater than the difference in its radius of curvature R7 − R8 Was 20.38 mm, and had an inner surface shape satisfying a relationship that was within a range of not more than 8 times (36 mm) of the thickness (4.5 mm) of the pipe to be connected to both main pipe connection portions 52 and 53. .
[0058]
Using this pipe joint 5, the same test as in Example 1 was performed.
as a result, Number of samples (n) = 3, but none of the samples was broken even after 200,000 times.
[0059]
(Comparative Example 2)
The pipe joint 5 shown in FIGS. 25 to 28 includes main pipe connecting portions 302 and 303 each having a TS joint type receptacle corresponding to a vinyl chloride resin pipe having a nominal diameter of 50 (inner diameter 51 mm, outer diameter 60 mm). Pipe fitting body A cheese-type vinyl chloride resin pipe fitting provided with branch pipe connection portions 304 comprising TS joint type receptacles provided at both end edges of 301 and corresponding to a vinyl chloride resin pipe having a nominal diameter of 50 (inner diameter 51 mm, outer diameter 60 mm) (Outer diameter 71 mm) was made as a prototype.
Using this pipe joint 300, the same test as in Example 1 was performed.
as a result, Number of samples (n) = 3, the number of times until destruction was 13875, 24367, and 19208, and the average was 19150, and the destruction site was the part indicated as g in FIG.
[0060]
【The invention's effect】
The pipe joint of the present invention is provided when piping such as a water pipe, which is subjected to positive pressure inside, is bent so as to be bent into an L shape or a T shape at a steep angle under restrictions inherent to the molding method. The mechanical tolerance is improved to reduce the maximum value of stress generated in the joint material due to the pressure difference between inside and outside, especially the pressure fluctuation during its use, and to reduce the long-term fracture caused by such stress. ing.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an L-shaped elbow-type pipe joint as an example of the pipe joint of the present invention.
FIG. 2 is a right side view of the pipe joint shown in FIG.
FIG. 3 is an inner surface shape in a section B of FIG.
4 is a shape of an inner surface in a cross section A of FIG.
5 is a front view showing an inner mold used for manufacturing the pipe joint shown in FIGS. 1 and 2. FIG.
6 is a front view showing one die of the inner mold shown in FIG. 5. FIG.
FIG. 7 is a cross-sectional view showing a cheese-type pipe joint as an example of the pipe joint of the present invention.
8 is a right side view of the pipe joint shown in FIG. 7. FIG.
9 is an inner surface shape in a cross section D of FIG.
FIG. 10 is a cross section of FIG. F Is the inner surface shape.
11 is an inner surface shape in a cross section G of FIG. 7;
12 is an inner surface shape in a section J of FIG. 7;
13 is a front view showing an inner mold used for manufacturing the pipe joint shown in FIGS. 7 and 8. FIG.
FIG. 14 is a cross-sectional view showing a cheese-type pipe joint of another example of the pipe joint of the present invention.
FIG. 15 is a cross-sectional view taken along the line KK of the portion 14;
16 is an inner surface shape in a cross section D of FIG. 14;
17 is an inner surface shape in a cross section E of FIG. 14;
FIG. 18 is a cross-sectional view of an example of a conventional elbow type pipe joint.
FIG. 19 is a right side view of FIG. 18;
20 is a shape of the inner surface in the cross section b of FIG.
21 is an inner surface shape in a section a of FIG.
22 is a front view showing an inner mold used for manufacturing the pipe joint shown in FIGS. 18 and 19. FIG.
FIG. 23 is a front view showing one die of the inner mold shown in FIG. 22;
24 is a perspective view showing a broken state of the pipe joint shown in FIGS. 18 and 19. FIG.
FIG. 25 is a cross-sectional view of an example of a conventional cheese-type pipe joint.
26 is a right side view of FIG. 25. FIG.
FIG. 27 is an inner surface shape in a cross section d of FIG. 25;
FIG. 28 is an inner surface shape in a cross section f of FIG.
29 is a front view showing an inner mold used to manufacture the pipe joint shown in FIGS. 25 and 26. FIG.
30 is a perspective view showing a broken state of the pipe joint shown in FIGS. 25 and 26. FIG.
[Explanation of symbols]
1,3,5 fittings
2,4 Inner type
11, 31, 51 Fitting body
12, 13 Pipe connection
32, 33 Main pipe connection
34 Branch pipe connection
111 Bent part

Claims

Across the edge of the pipe joint the body having a bent portion, a L-shaped elbow type pipe joint tubes can be connected tube connection portion of the circular cross section is provided, the two pipe connecting portion of the pipe joint body The distance D1 between the opposed inner surface portions intersecting the plane including both the tube axes of the two tube connecting portions at the side edge portion is smaller than the distance D2 between the opposed inner surface portions farthest from the plane; and The pipe joint is characterized in that it has an inner surface shape satisfying a relationship in which the difference D2-D1 in the distance is in a range of not less than half and not more than twice the thickness of the pipe to be connected.

At the edge of the pipe joint body on both pipe connecting portions, the radius of curvature R1 of the inner surface that is the inner side of the bent portion is larger than the radius of curvature R2 of the inner surface that is the outer side of the bent portion, and the difference R1- 2. The pipe joint according to claim 1, wherein R2 has an inner surface shape that satisfies a relationship in which R2 is in a range of four times or less the thickness of the pipe to be connected.

Each edge of the pipe joint the body forming a T-shaped cross section, a cheese-type pipe joint tubes can be connected tube connection portion of the circular cross section is provided, each tube connecting portions of the pipe joint body The distance D3 between the opposed inner surface portions intersecting the plane including all the tube axes of the respective tube connecting portions at the end edge on the side is smaller than the distance D4 between the opposed inner surface portions farthest from the plane; and A pipe joint having an inner surface shape satisfying a relationship in which a difference D4-D3 in the distance is in a range of not less than half and not more than twice the thickness of the pipe to be connected.

The cheese-type pipe joint has a main pipe connection portion provided at both end edges in the main pipe axis direction of the pipe joint body, and a branch pipe connection portion provided at an end edge portion in the branch pipe axis direction orthogonal to the main pipe axis. The curvature radius R3 of the inner surface on the side of the branch pipe connection portion is larger than the curvature radius R4 of the inner surface on the side farther from the branch pipe connection portion at the end edges on the both main pipe connection portions side. 4. The pipe joint according to claim 3, wherein the difference R3-R4 is an inner surface shape satisfying a relationship that is in a range of 8 times or less of a thickness of a pipe to be connected to the main pipe connecting portion. .