JP4004204B2

JP4004204B2 - Pipe joint structure and reinforcing tube for insertion tube

Info

Publication number: JP4004204B2
Application number: JP2000069998A
Authority: JP
Inventors: 昭人戸継
Original assignee: Waterworks Technology Development Organization Co Ltd
Current assignee: Waterworks Technology Development Organization Co Ltd
Priority date: 2000-03-14
Filing date: 2000-03-14
Publication date: 2007-11-07
Anticipated expiration: 2020-03-14
Also published as: JP2001254880A

Description

【０００１】
【発明の属する技術分野】
本発明は、受口管部に挿入接続された合成樹脂製の挿入管部の外周面と前記受口管部の内周面との間、又は、前記挿入管部に外装する状態で受口管部に管軸芯方向から固定連結される押輪の内周面と前記挿入管部の外周面との間に、挿入管部の外周面に喰い込み可能な抜止部材を設け、前記受口管部と挿入管部との相対離脱移動に連れて抜止部材を縮径側に変位させるカム手段を設けるとともに、前記挿入管部内の先端部から少なくとも抜止部材の喰い込み作用箇所に相当する部位又はその近くまでの領域に補強筒体を内嵌してある管継手構造に関する。
【０００２】
【従来の技術】
この種の管継手構造では、地震や不同沈下等に起因して受口管部と挿入管部とに離脱方向への外力（管軸芯方向での引張力）が作用しても、受口管部と挿入管部との管軸芯方向での相対離脱移動に連れて抜止部材がカム手段によって縮径側に変位されるため、抜止部材が挿入管部の外周面により深く喰い込むことになり、その結果、受口管部と挿入管部との離脱抵抗が増大する。
【０００３】
しかも、挿入管部が鋳鉄等の金属に比して管軸芯方向の伸び特性及び撓み特性に勝れたポリエチレン等の合成樹脂で製作されているから、地震や不同沈下等に起因する管軸芯方向の引張力や曲げモーメント等の外力を、挿入管部自体の伸び特性及び撓み特性を利用して吸収することができる。
【０００４】
更に、抜止部材の縮径側への変位に連れて合成樹脂製の挿入管部に作用する締付け力が増大しても、この増大する締付け力を、挿入管部に内嵌した補強筒体にて受止めることができるから、抜止部材の締付け力による挿入管部の径方向内方への変形を抑制することができる。
【０００５】
それ故に、離脱抵抗の増大と挿入管部による外力吸収作用及び挿入管部の径方向での変形抑制作用との相乗によって、受口管部からの挿入管部の離脱防止機能を高めることができるのである。
【０００６】
しかし、組付け作業途中での振動や衝撃或いは輸送流体の流速等に起因する補強筒体の位置ずれを抑制するために、例えば、実公平５−９５８２号公報等において開示されているように、挿入管部に挿入される補強筒体の内嵌筒部の外径を、それの管軸芯方向の全域に亘って挿入管部の内径よりも大に構成して、該補強筒体を挿入管部内に圧入固定すると、圧入時に、挿入管部の内周面と補強筒体の外周面との間での摩擦抵抗力が強大となり、挿入管部に対して補強筒体を人為操作で圧入する場合には、その圧入作業に多大の労力と時間を要し、また、機械力を利用して補強筒体を挿入管部に圧入する場合では、圧入装置が大型化し易い欠点がある。
【０００７】
特に、挿入管部に圧入される補強筒体の管軸芯方向での嵌合長さが長くなればなる程、圧入作業能率の低下を招来し易く、更に、合成樹脂製の挿入管部の場合では、内径側での寸法公差が鋳鉄製の挿入管部に比して大きいため、補強筒体の内嵌筒部における外径の寸法公差が大径側に、かつ、挿入管部の内径の寸法公差が小径側にそれぞれ片寄った場合には、挿入管部に対する補強筒体の圧入力が著しく増大し、前述の欠点を一層助長し易い。
【０００８】
そこで、本願出願人は、前述の欠点を解決する方法として、前記挿入管部に内嵌される補強筒体の内嵌筒部の外径を、挿入管部の内径よりも小に構成するとともに、前記補強筒体の周方向複数箇所で、かつ、内嵌時に挿入管部の先端部側に対応する部位には、挿入管部の内周面よりも径方向の外方に突出位置し、かつ、挿入管部内への挿入に連れて径方向内方に弾性変形する抜止め片を、湾曲する状態で一体形成した管継手構造を開発した（例えば、特開平１１−２８７３６８号公報参照）。
【０００９】
【発明が解決しようとする課題】
前述の管部継手構造では、前記挿入管部の内周面とこれに内嵌された補強筒体の内嵌筒部の外周面との間に隙間があっても、地震や不同沈下等の外力に起因する受口管部と挿入管部との相対離間移動によって、抜止め部材がカム手段によって縮径側に変位されたとき、或いは、人為操作で抜止め部材をカム手段によって縮径側に変位させたとき、挿入管部の内周面が補強筒体の内嵌筒部の外周面に圧接されれば、挿入管部の径方向内方への変形を効果的に抑制することができることを知見し、その変形抑制効果が得られる範囲内において、前記補強筒体の内嵌筒部の外径を挿入管部の内径よりも小に構成することにより、挿入管部に対する補強筒体の内嵌作業時の挿入抵抗を軽減することができる。
【００１０】
それでいて、補強筒体の内嵌筒部が挿入管部内の所定位置に内嵌された状態では、補強筒体に形成してある抜止め部が、挿入管部の内周面との接当によって径方向内方に弾性変形して、それの弾性復帰力で抜止め部が挿入管部に圧接されて摩擦抵抗力が生じるから、組付け作業途中での振動や衝撃或いは輸送流体の流速等に起因する補強筒体の位置ずれを抑制することができる。
【００１１】
しかしながら、従来の管継手構造では、前記各抜止め片の管軸芯方向での長さ及び径方向外方への突出代が一定に形成されていて、各抜止め片の湾曲部分の同じ部位が、挿入管部の内周面の先端側角部に接当するように構成されているため、各抜止め片の径方向内方への弾性変形に連れて補強筒体に抜け出し方向の分力が発生し、その分だけ補強筒体の外れ防止効果が低下していた。
【００１２】
また、挿入管部の内周面の先端側角部に対する各抜止め片の引っ掛かり力を高めるために、各抜止め片の径方向外方への突出代を大きくすることが考えられるが、各抜止め片の湾曲部分が径方向内方に弾性変形し難くなり、挿入管部に対する補強筒体の装着作業に手間取るとともに、多くの労力を要する問題がある。
【００１３】
本発明は、上述の実状に鑑みて為されたものであって、その主たる課題は、前記各抜止め片に対する簡単かつ安価な改造をもって、補強筒体の装着作業の容易化を図りつつ、挿入管部に装着された補強筒体の外れ防止効果を向上することができる管継手構造を提供する点にある。
【００１４】
【課題を解決するための手段】
本発明の請求項１による特徴構成は、受口管部に挿入接続された合成樹脂製の挿入管部の外周面と前記受口管部の内周面との間、又は、前記挿入管部に外装する状態で受口管部に管軸芯方向から固定連結される押輪の内周面と前記挿入管部の外周面との間に、挿入管部の外周面に喰い込み可能な抜止部材を設け、前記受口管部と挿入管部との相対離脱移動に連れて抜止部材を縮径側に変位させるカム手段を設けるとともに、前記挿入管部内の先端部から少なくとも抜止部材の喰い込み作用箇所に相当する部位又はその近くまでの領域に補強筒体を内嵌し、この補強筒体の内嵌筒部の外径を、前記挿入管部の内径よりも小に構成し、前記補強筒体の周方向複数箇所には、挿入管部の内周面よりも径方向の外方に突出位置して、挿入管部内への挿入に連れて径方向内方に弾性変形する抜止め片を形成してある管継手構造であって、
前記補強筒体の挿入管部の先端側に対応する基端部分の周方向複数箇所に、それの端面に開口するスリットを形成し、このスリットの隣接間に位置する各片を同一円周線上において径方向外方に折り曲げることにより前記抜止め片を形成するとともに、前記抜止め片の折曲げ位置から先端までの管軸芯方向での長さを複数の長さに構成して、前記挿入管部に対する複数の抜止め片の接当位置を管軸芯方向で異ならせてある点にある。
【００１５】
上記特徴構成によれば、前記補強筒体の周方向複数箇所に形成された抜止め片のうち、挿入管部に対する接当位置が最も挿入管部の先端側に位置する抜止め片が、挿入管部の内周面の先端側角部に接当している条件下では、その他の抜止め片は、挿入管部の内周面に入込み状態で接当することになるから、この入込み状態にある抜止め片と挿入管部の内周面との接当による抜止め作用により、挿入管部の内周面の先端側角部との接当に伴う抜止め片の径方向内方への弾性変形によって、補強筒体に抜け出し方向の分力が発生しても、補強筒体の抜け出し移動を抑制することができる。
【００１６】
しかも、前記挿入管部に補強筒体を挿入する際、複数の抜止め片の径方向内方への弾性変形開始時期がずれるから、複数の抜止め片を同時に弾性変形させる場合に比して、補強筒体の内嵌作業時の挿入抵抗を軽減することができる。
【００１７】
従って、前記挿入管部に対する複数の抜止め片の接当位置を少なくとも管軸芯方向で二個所以上に異ならせるだけの簡単かつ安価な改造をもって、補強筒体の装着作業の容易化を図りつつ、挿入管部に装着された補強筒体の外れ防止効果を高めることができるから、組付け作業途中での振動や衝撃或いは輸送流体の流速等に起因する補強筒体の位置ずれを抑制することができる。
【００２０】
本発明の請求項２による管部継手構造の特徴構成は、前記抜止め片のうち、管軸芯方向での長さが小さい抜止め片の周方向幅が、管軸芯方向での長さが大きい抜止め片の周方向幅よりも小に構成されている点にある。
【００２１】
上記特徴構成によれば、例えば、各抜止め片の周方向幅が同一に構成されている場合、或いは、挿入管部に対する接当位置が補強筒体の挿入先端側に位置する抜止め片の周方向幅が、それよりも挿入管部の先端側で接当する抜止め片の周方向幅よりも大に構成されている場合に比して、挿入管部に対する補強筒体の内嵌作業をより少ない労力で能率良く容易に行うことができる。
【００２２】
本発明の請求項３による管部継手構造の特徴構成は、前記抜止め片の周方向両側縁が、径方向外方にエッジが突出する状態に折曲げ形成されている点にある。
【００２３】
上記特徴構成によれば、前記補強筒体の内嵌筒部が挿入管部内の所定位置に内嵌されるに連れて、補強筒体の周方向複数箇所に折曲げ形成された抜止め片の抜止め片が、挿入管部の内周面との接当によって径方向内方に弾性変形しながら圧接され、しかも、このとき、各抜止め片の周方向両側縁に形成されたエッジが挿入管部の内周面に喰込むことになるから、組付け作業途中での振動や衝撃或いは輸送流体の流速等に起因する補強筒体の位置ずれをより効果的に抑制することができる。
【００２４】
更に、前記抜止め片の折曲げ加工によって該抜止め片のエッジを径方向外方に突出させるから、例えば、前記抜止め片の外周面に、補強筒体の内嵌筒部が挿入管部内の所定位置に内嵌されるに連れて該挿入管部の内周面に喰込む専用の喰込み部を突出形成する場合に比して、喰込み部を備えた補強筒体の製造コストの低廉化を図ることができる。
【００２５】
本発明の請求項４による特徴構成は、合成樹脂製の挿入管部に内嵌される補強筒体の内嵌筒部の外径を、前記挿入管部の内径よりも小に構成し、前記補強筒体の周方向複数箇所には、挿入管部の内周面よりも径方向の外方に突出位置して、挿入管部内への挿入に連れて径方向内方に弾性変形する抜止め片を形成してある挿入管部用補強筒体であって、
前記補強筒体の挿入管部の先端側に対応する基端部分の周方向複数箇所に、それの端面に開口するスリットを形成し、このスリットの隣接間に位置する各片を同一円周線上において径方向外方に折り曲げることにより前記抜止め片を形成するとともに、前記抜止め片の折曲げ位置から先端までの管軸芯方向での長さを複数の長さに構成して、前記挿入管部に対する複数の抜止め片の接当位置を管軸芯方向で異ならせてある点にある。
【００２７】
【発明の実施の形態】
〔第１実施形態〕
図１〜図６は、鋳鉄製の継手本体Ａの受口管部１に、合成樹脂製の流体輸送管の一例であるポリエチレン製の水道管Ｐの一端側の挿入管部２を密封状態で挿入接続するための本発明の管継手構造を示し、前記受口管部１の内周面１ａに、管軸芯Ｘ方向での溝幅が異なる二つの環状溝１Ａ，１Ｂを形成し、そのうち、受口管部１の受口側に位置する溝幅の小さな第１環状溝１Ａ内には、受口管部１の内周面１ａと挿入管部２の外周面２ａとの間を密封する第１弾性シール材３を装着するとともに、奥側に位置する溝幅の大きな第２環状溝１Ｂ内には、受口管部１に挿入接続された挿入管部２の外周面２ａに喰い込み可能な抜止部材の一例で、弾性的に縮径変形可能なほぼＣの字状に形成された合成樹脂製（例えば、ポリアセタール等）又は金属製（例えば、ステンレス鋼等）の抜止めリング４と、該抜止めリング４よりも奥側位置において、受口管部１の内周面１ａと挿入管部２の外周面２ａとの間を密封する第２弾性シール材５とを装着してある。
【００２８】
前記受口管部１の内周面１ａのうち、前記第２環状溝１Ｂ内に位置する内周面部分には、図１、図６に示すように、受口管部１と挿入管部２との管軸芯Ｘ方向での相対離脱移動に連れて抜止めリング４を縮径側に変位させる、つまり、抜止めリング４を、それの弾性復元力に抗して縮径変形させるカム手段としてのテーパー状のカム面６を形成するとともに、前記挿入管部２内の先端から少なくとも抜止めリング４の喰い込み作用箇所に相当する部位又はその近くまでの領域（当該第１実施形態では、前記挿入管部２のうち、受口管部１内に挿入される管部分よりも少し長い領域）に、抜止めリング４の縮径変形に伴う挿入管部２の径方向内方への変形を抑制するステンレス鋼製（金属製）の補強筒体７を内嵌してある。
【００２９】
前記補強筒体７のうち、挿入管部２に内嵌される内嵌筒部７Ａの外径Ｄ１を、前記挿入管部２の内径Ｄ２よりも小に構成する、詳しくは、挿入管部２の内径Ｄ２の公差範囲内での最小内径Ｄ２よりも僅かに小に構成するとともに、前記補強筒体７の先端部分７ｄを、先端側ほど小径となるテーパー状に絞り形成してある。
【００３０】
更に、前記補強筒体７のうち、内嵌時に挿入管部２の先端部に対応する部位又はその近く（当該実施形態では、挿入管部２内の所定位置に内嵌した状態で該挿入管部２の先端部に対応する基端部分）には、挿入管部２の内周面２ｃよりも径方向の外方に突出位置し、かつ、挿入管部２内への挿入に連れて径方向内方に弾性変形する抜止め部７Ｂを形成してある。
【００３１】
前記抜止め部７Ｂは、図２、図３に示すように、補強筒体７の基端部分で、かつ、その周方向４箇所において端面に開口する状態で形成されたＶ字状のスリット７ｅの隣接間に位置する部分を径方向外方に折曲げて形成された径方向内方に弾性変形可能な抜止め片７ａ，７ｂから構成されている。
【００３２】
前記抜止め片７ａ，７ｂのうち、周方向で一つ置きに位置する二個の第１抜止め片７ａの管軸芯方向での長さＬ１を、他の二個の第２抜止め片７ｂの管軸芯方向での長さＬ２よりも小に構成するとともに、両第１抜止め片７ａ及び両第２抜止め片７ｂの各折曲げ位置を、スリット７ｅの最低部位置を通る同一円周線上に構成して、前記挿入管部２の内周面２ｃに対する第１抜止め片７ａの接当位置（係止位置）と第２抜止め片７ｂの接当位置（係止位置）とを、管軸芯方向で異ならせてある。
【００３３】
前記抜止め片７ａ，７ｂのうち、管軸芯方向での長さが小さい第１抜止め片７ａの周方向幅Ｗ２が、管軸芯方向での長さが大きい第２抜止め片７ｂの周方向幅Ｗ１よりも小幅に構成されているとともに、前記内嵌筒部７Ａの外周面から各抜止め片７ａ，７ｂの先端部までの径方向での間隔（突出代）、つまり、各抜止め片７ａ，７ｂの先端部における径方向外方への突出代が同一に構成されている。
【００３４】
更に、前記各抜止め片７ａ，７ｂのうち、少なくとも第１抜止め片７ａの先端縁には、挿入管部２内への挿入に連れてそれの弾性復元力で挿入管部２の内周面２ｃに圧接されるエッジ７ｃが形成されている。
【００３５】
前記抜止めリング４の内周面には、挿入管部２の外周面２ａに喰い込み可能な多数の喰込み突起４ａが形成されているとともに、前記抜止めリング４の外周面４ｂは、前記カム面６に沿うテーパー面に形成されている。
【００３６】
また、前記抜止めリング４のテーパー状外周面４ｂとカム面６とが接当していない状態でも、抜止めリング４の縮径側への弾性復元力によって、それの喰込み突起４ａが挿入管部２の外周面２ａに僅かに喰い込むように構成されているとともに、前記挿入管部２の先端部には、挿入管部２の挿入に連れて抜止めリング４を弾性復元力に抗して拡径変形させるためのテーパー状の第２カム面２ｂが形成されている。
【００３７】
前記継手本体Ａの受口管部１の他端部には、他の配管や仕切弁等の管継手具等に設けられたフランジ部１０に対してボルト１１・ナット１２を介して連結されるフランジ部１３が一体形成されている。
【００３８】
そして、前記挿入管部２内の所定領域に亘って補強筒体７の内嵌筒部７Ａを内嵌した状態で、図１及び図４に示すように、前記挿入管部２の内周面２ｃとこれに内嵌された補強筒体７の内嵌筒部７Ａの外周面との間に隙間があっても、図６に示すように、地震や不同沈下等による外力に起因して受口管部１と挿入管部２とが相対離間移動すると、カム手段としてのカム面６によって抜止めリング４が縮径変形され、それに連れて挿入管部２が径方向内方に縮径変形されて、挿入管部２の内周面２ｃが補強筒体７の内嵌筒部７Ａの外周面に圧接されるから、それ以降の挿入管部２の径方向内方への変形を抑制することができる。
【００３９】
更に、図６に示すように、前記補強筒体７の周方向複数箇所に一体形成された抜止め片７ａ，７ｂのうち、挿入管部２に対する接当位置が最も挿入管部２の先端側に位置する第２抜止め片７ｂが、挿入管部２の内周面２ｃの先端側角部に接当している条件では、その他の第１抜止め片７ａは、挿入管部２の内周面２ｃに入込み状態で接当することになり、特に、この場合では、第１抜止め片７ａの端縁に形成されたエッジ７ｃが、挿入管部２の内周面２ｃに弾性的に圧接されているから、この入込み状態にある第１抜止め片７ａと挿入管部２の内周面２ｃとの圧接（喰込み）による抜止め作用により、挿入管部２の内周面２ｃの先端側角部との接当に伴う第２抜止め片７ｂの径方向内方への弾性変形によって、補強筒体７に抜け出し方向の分力が発生しても、補強筒体７の抜け出し移動を抑制することができる。
【００４０】
しかも、前記挿入管部２に補強筒体７を挿入する際、複数の抜止め片７ａ，７ｂの径方向内方への弾性変形開始時期がずれるから、つまり、第１抜止め片７ａの径方向内方への弾性変形開始時期と第２抜止め片７ｂの径方向内方への弾性変形開始時期とがずれるから、複数の抜止め片片７ａ，７ｂを同時に弾性変形させる場合に比して、補強筒体７の内嵌作業時の挿入抵抗を軽減することができる。
【００４１】
〔第２実施形態〕
図７、図８は、鋳鉄製の継手本体Ａの受口管部１に、合成樹脂製の流体輸送管の一例であるポリエチレン製の水道管Ｐの挿入管部２を密封状態で挿入接続するための管継手構造の別実施形態を示し、前記挿入管部２に、受口管部１の内周面１ａと挿入管部２の外周面２ａとの間を密封可能な合成ゴム製（例えば、スチレンブタジエンゴム）の弾性シール材２０と、該弾性シール２０を管軸芯Ｘ方向から押圧して密封状態（水密状態）にまで圧縮可能な鋳鉄製の押輪２１とを外装するとともに、前記押輪２１と受口管部１とを管軸芯Ｘ方向から締付け固定連結する締結手段２２を設けてある。
【００４２】
前記押輪２１の内周面２１ａと挿入管部２の外周面２ａとの間には、挿入管部２の外周面２ａに喰い込み可能な抜止部材の一例で、管軸芯Ｘ方向において弾性的に縮径変形可能なほぼＣの字状に形成された合成樹脂製（例えば、ポリアセタール等）又は金属製（例えば、ステンレス鋼等）の抜止めリング４を設けるとともに、前記押輪２１の内周面２１ａには、前記締結手段２２の締付け操作に伴う押輪２１と受口管部１との相対近接移動に連れて前記抜止めリング４を縮径側に変位させる、つまり、抜止めリング４をそれの弾性復元力に抗して縮径変形させるカム手段の一例で、受口管部１側ほど大径となるテーパー状のカム面６を形成してある。
【００４３】
前記弾性シール材２０とこれに対して管軸芯Ｘ方向で対向する押輪２１及び抜止めリング４との間には、前記締結手段２２による締付け操作の前半で弾性シール材２０のみを押圧圧縮し、該弾性シール材２０が設定圧縮状態になった以降の締付け操作で、前記カム面６により抜止めリング４を喰い込み状態にまで前記弾性復元力に抗して縮径変形させる順次作動手段２３を設けてある。
【００４４】
更に、前記抜止めリング４が挿入管部２の外周面２ａに少し喰い込んでいる状態において、挿入接続された受口管部１と挿入管部２とに離脱方向への外力（管軸芯Ｘ方向での引張力）が作用して、受口管部１と挿入管部２とが相対離脱移動すると、これに連れて抜止めリング４のテーパー状外周面４ｂがカム面６に押圧されて縮径変形し、抜止めリング４の喰込み突起４ａが挿入管部２の外周面２ａに更に喰い込むように構成されている。
【００４５】
そして、前記挿入管部２内の先端から少なくとも抜止めリング４の喰い込み作用箇所に相当する部位又はその近くまでの領域（当該第２実施形態では、前記挿入管部２のうち、受口管部１内に挿入される管部分の長さと押輪２１の管軸芯方向長さとの和よりも少し長い領域）に、抜止めリング４の縮径変形に伴う挿入管部２の径方向内方への変形を抑制するステンレス鋼製（金属製）の補強筒体７を内嵌してある。
【００４６】
前記補強筒体７のうち、挿入管部２に内嵌される内嵌筒部７Ａの外径Ｄ１を、前記挿入管部２の内径Ｄ２よりも小に構成する、詳しくは、挿入管部２の内径Ｄ２の寸法公差範囲内での最小内径Ｄ２よりも僅かに小に構成するとともに、前記補強筒体７の先端部分７ｄを、先端側ほど小径となるテーパー状に絞り形成してある。
【００４７】
更に、前記補強筒体７のうち、内嵌時に挿入管部２の先端部に対応する部位又はその近く（当該実施形態では、挿入管部２内の所定位置に内嵌した状態で該挿入管部２の先端部に対応する基端部分）には、挿入管部２の内周面２ｃよりも径方向の外方に突出位置し、かつ、挿入管部２内への挿入に連れて径方向内方に弾性変形する抜止め部７Ｂを形成してある。
【００４８】
前記抜止め部７Ｂは、補強筒体７の基端部分で、かつ、その周方向４箇所に形成されたＶ字状のスリット７ｅの隣接間に位置する部分を径方向外方に折曲げて形成された径方向内方に弾性変形可能な抜止め片７ａ，７ｂから構成されている。
【００４９】
前記抜止め片７ａ，７ｂのうち、周方向で一つ置きに位置する二個の第１抜止め片７ａの管軸芯方向での長さＬ１を、他の二個の第２抜止め片７ｂの管軸芯方向での長さＬ２よりも小に構成するとともに、両第１抜止め片７ａ及び両第２抜止め片７ｂの各折曲げ位置を、スリット７ｅの最低部位置を通る同一円周線上に構成して、前記挿入管部２の内周面２ｃに対する第１抜止め片７ａの接当位置（係止位置）と両第２抜止め片７ｂの接当位置（係止位置）とを、管軸芯方向で異ならせてある。
【００５０】
前記抜止め片７ａ，７ｂのうち、管軸芯方向での長さが小さい第１抜止め片７ａの周方向幅Ｗ２が、管軸芯方向での長さが大きい第２抜止め片７ｂの周方向幅Ｗ１よりも小幅に構成されているとともに、前記各抜止め片７ａ，７ｂの径方向外方への突出代が同一に構成されている。
【００５１】
更に、前記各抜止め片７ａ，７ｂのうち、少なくとも管軸芯方向での長さが短い第１抜止め片７ａの端縁には、挿入管部２内への挿入に連れてそれの弾性復元力で挿入管部２の内周面２ｃに圧接されるエッジ７ｃが形成されている。
【００５２】
前記順次作動手段２３は、図８に示すように、前記抜止めリング４と弾性シール材２０との間に、前記押輪２１と受口管部１との相対近接移動に連れて弾性シール材２０を管軸芯Ｘ方向から押圧圧縮する第１押圧面２４ａと、前記抜止めリング４を押輪２１のカム面６側に管軸芯Ｘ方向から押圧可能な第２押圧面２４ｂとを備えたステンレス鋼等の金属製又は合成樹脂製の円環状の中間押圧体２４を設け、この中間押圧体２４と押輪２１の内周面との径方向で対向又はほぼ対向する部位に亘って、前記押輪２１と受口管部１との相対近接移動に連れて前記弾性シール材２０が設定圧縮状態になるまでは、前記押輪２１のカム面６と中間押圧体２４の第２押圧面２４ｂとの管軸芯Ｘ方向での対向間隔を非喰い込み状態にある抜止めリング４が縮径側に弾性変形しない間隔に規制し、かつ、前記弾性シール材２０が設定圧縮状態になったとき、中間押圧体２４の外周面と押輪２１の内周面２１ａとの間で剪断されて前記間隔規制を解除する、つまり、前記押輪２１のカム面６と中間押圧体２４の第２押圧面２４ｂとの管軸芯Ｘ方向での相対近接移動を許す間隔規制部材（銅合金やアルミニウム合金等の金属製の頭付きシヤーピン）２５を設けて構成されている。
【００５３】
前記締結手段２２は、受口管部１の連結フランジ部２６のボルト挿通孔２７と押輪２１の連結突起２８のボルト挿通孔２９とのうち、管軸芯Ｘ方向で相対向する両ボルト挿通孔２７，２９に亘って挿通されるＴ字状のボルト２２Ａとナット２２Ｂとから構成されている。
【００５４】
尚、前記補強筒体７及び抜止めリング４の詳細は、第１実施形態と同一であるため、同一の構成には同一の符号を付記して、それの説明は省略する。
【００５５】
〔第３実施形態〕
前述の各実施形態では、前記抜止め部７Ｂを、補強筒体７の基端部で、かつ、その周方向４箇所に形成されたＶ字状のスリット７ｅの隣接間に位置する部分を径方向外方に折曲げて形成された径方向内方に弾性変形可能な抜止め片７ａ，７ｂから構成したが、図９に示すように、補強筒体７のうち、その基端から筒軸芯（管軸芯）方向の中央側に偏位した中間部分の周方向複数箇所を、径方向外方に打出し形成して、この打出された径方向内方に弾性変形可能な複数の抜止め片７ａ，７ｂをもって前記抜止め部７Ｂを構成してもよい。
【００５６】
また、前記抜止め片７ａ，７ｂのうち、周方向で一つ置きに位置する二個の第１抜止め片７ａの管軸芯方向での長さＬ１を、他の二個の第２抜止め片７ｂの管軸芯方向での長さＬ２よりも小に構成するとともに、両第１抜止め片７ａ及び両第２抜止め片７ｂの各折曲げ位置を、スリット７ｅの最低部位置を通る同一円周線上に構成して、前記挿入管部２の内周面２ｃに対する第１抜止め片７ａの接当位置（係止位置）と両第２抜止め片７ｂの接当位置（係止位置）とを、管軸芯方向で異ならせてある。
尚、その他の構成は、第１実施形態で説明した構成と同一であるから、同一の構成箇所には、第１実施形態と同一の番号を付記してそれの説明は省略する。
【００５７】
〔第４実施形態〕
前述の各実施形態では、前記内嵌筒部７Ａの外周面から各抜止め片７ａ，７ｂの先端部までの径方向での間隔（突出代）、つまり、各抜止め片７ａ，７ｂの先端部における径方向外方への突出代を同一に構成したが、図１０に示すように、前記第１抜止め片７ａの先端部における径方向外方への突出代を、第２抜止め片７ｂの先端部における径方向外方への突出代よりも大に構成してもよい。
【００５８】
また、この第４実施形態では、第１実施形態と同様に、前記第１抜止め片７ａの管軸芯方向での長さＬ１を、第２抜止め片７ｂの管軸芯方向での長さＬ２よりも小に構成するとともに、両第１抜止め片７ａ及び両第２抜止め片７ｂの各折曲げ位置を、スリット７ｅの最低部位置を通る同一円周線上に構成して、前記挿入管部２の内周面２ｃに対する第１抜止め片７ａの接当位置（係止位置）と両第２抜止め片７ｂの接当位置（係止位置）とが管軸芯方向で異なるように構成し、更に、前記第１抜止め片７ａの周方向幅Ｗ２を、第２抜止め片７ｂの周方向幅Ｗ１よりも小幅に構成してある。
【００５９】
尚、当該第４実施形態とは逆に、前記第２抜止め片７ｂの先端部における径方向外方への突出代を、第１抜止め片７ａの先端部における径方向外方への突出代よりも大に構成して実施してもよい。
【００６０】
〔第５実施形態〕
前述の各実施形態では、前記抜止め部７Ｂを、補強筒体７の周方向複数箇所を径方向外方に折曲げて形成された径方向内方に弾性変形可能な抜止め片７ａ，７ｂから構成するとともに、各抜止め片７ａ，７ｂの外周面を円弧状に形成したが、図１１に示すように、前記スリット７ｅに沿う各抜止め片７ａ，７ｂの周方向両側縁を、径方向外方に向かって第２のエッジ７ｆが突出する状態に折曲げ形成して実施してもよい。
【００６１】
この実施形態によれば、前記補強筒体７の内嵌筒部７Ａが挿入管部２内の所定位置に内嵌されるに連れて、補強筒体７の周方向複数箇所に折曲げ形成された抜止め部７Ｂの抜止め片７ａ，７ｂが、挿入管部２の内周面２ｃとの接当によって径方向内方に弾性変形しながら圧接され、しかも、このとき、各抜止め片７ａ，７ｂの周方向両側縁に形成された第２エッジ７ｆが挿入管部２の内周面２ｃに喰込むことになるから、組付け作業途中での振動や衝撃或いは輸送流体の流動（流速）等に起因する補強筒体７の位置ずれをより効果的に抑制することができる。
【００６２】
しかも、前記抜止め片７ａ，７ｂの折曲げ加工によって該抜止め片７ａ，７ｂの第２エッジ７ｆを径方向外方に突出させるから、例えば、前記抜止め片７ａ，７ｂの外周面に、補強筒体７の内嵌筒部７Ａが挿入管部２内の所定位置に内嵌されるに連れて、挿入管部２の内周面２ｃに喰込む専用の喰込み部を突出形成する場合に比して、喰込み部を備えた補強筒体７の製造コストの低廉化を図ることができる。
【００６３】
〔その他の実施形態〕
（１）前述の各実施形態では、継手本体Ａとして、受口管部１の管軸芯方向他端側に連結用フランジ部が一体形成されたものを例に挙げて説明したが、この構成に限定されるものではなく、例えば、挿入管部２が各別に挿入接続される一対の受口管部１を備えた継手本体Ａであってもよく、また、このような継手本体Ａの代わりに、仕切弁等の管継手器具の接続口部側に形成されている受口管部であってもよい。
【００６４】
（２）前述の各実施形態では、挿入管部２に対する抜止め片７ａ，７ｂの接当位置（係止位置）を、円周方向に沿って一個単位で交互に管軸芯方向に異ならせたが、前記抜止め片７ａ，７ｂの接当位置を円周方向に沿って二個以上の複数個単位で管軸芯方向に交互に異ならせて構成してもよい。
また、前述の各実施形態では、挿入管部２に対する接当位置（係止位置）が管軸芯方向で異なる二種類の抜止め片７ａ，７ｂを形成したが、挿入管部２に対する接当位置（係止位置）が管軸芯方向で三箇所以上異なる三種類以上の抜止め片から構成してもよい。
更に、前記挿入管部２に対する接当位置（係止位置）が管軸芯方向で異なる複数種類の抜止め片を、それらの接当位置が螺旋又はＶ字等を描く状態で円周方向に配置してもよい。
要するに、前記挿入管部２に対する複数の抜止め片の接当位置（係止位置）を少なくとも管軸芯方向で二個所以上に異ならせてあればよい。
【００６５】
（３）前述の第５実施形態では、前記補強筒体７の内嵌筒部７Ａが挿入管部２内の所定位置に内嵌されるに連れて挿入管部２の内周面２ｃに喰込む喰込み部を、抜止め片７ａ、７ｂの周方向両側縁に形成された半径方向外方に突出するエッジ７ｆから構成したが、この喰込み部を、前記抜止め片７ａ、７ｂの外周面に突出形成される突起から構成してもよい。
【００６６】
（４）前述の各実施形態では、前記抜止めリング４の縮径変形に伴う挿入管部２の径方向内方への変形を抑制する補強筒体７を、挿入管部２内の先端から抜止めリング４の喰い込み作用箇所を超えた広い領域に亘って内嵌したが、この補強筒体７は、挿入管部２内の先端又はその近くから少なくとも抜止めリング４の喰い込み作用箇所相当する部位又はその近くまでの領域に亘って内嵌されていればよい。
【００６７】
（５）前述の第４実施形態では、前記抜止め片７ａ，７ｂとして、それの先端部における径方向外方への突出代が異なる二種類のもから構成したが、径方向外方への突出代が三つ以上に異なる三種類の抜止め片から構成してもよい。
【００６８】
（６）前記各実施形態では、前記補強筒体７を金属の一例であるステンレス鋼から製作したが、合成樹脂から製作してもよい。
【図面の簡単な説明】
【図１】本発明の管継手構造の第１実施形態を示す縦断面図
【図２】補強筒体の斜視図
【図３】補強筒体の正面図
【図４】挿入管部と補強筒体との内嵌途中の縦断面図
【図５】挿入管部と補強筒体との内嵌完了時の縦断面図
【図６】受口管部と挿入管部とが相対離間移動したときの縦断面図
【図７】本発明の管継手構造の第２実施形態を示す縦断面図
【図８】組付け途中の要部の拡大断面図
【図９】本発明の管継手構造の第３実施形態を示す補強筒体の縦断面図
【図１０】本発明の管継手構造の第４実施形態を示す補強筒体の正面図
【図１１】本発明の管継手構造の第５実施形態を示す補強筒体の一部切欠き正面図
【符号の説明】
１受口管部
１ａ内周面
２挿入管部
２ａ外周面
２ｃ内周面
４抜止部材（抜止めリング）
６カム手段（テーパー面）
７補強筒体
７Ａ内嵌筒部
７ａ抜止め片
７ｂ抜止め片
７ｃエッジ
２１押輪
２１ａ内周面
Ｘ管軸芯[0001]
BACKGROUND OF THE INVENTION
The present invention provides a receiving port between an outer peripheral surface of an insertion tube portion made of a synthetic resin inserted and connected to the receiving tube portion and an inner peripheral surface of the receiving tube portion, or in a state of covering the insertion tube portion. A retaining member capable of biting into the outer peripheral surface of the insertion tube portion is provided between the inner peripheral surface of the press ring fixedly connected to the tube portion from the tube axis direction and the outer peripheral surface of the insertion tube portion, and the receiving tube A cam means for displacing the retaining member to the reduced diameter side in accordance with the relative detachment movement between the insertion tube portion and the insertion tube portion, and a portion corresponding to at least a biting action location of the retaining member from the distal end portion in the insertion tube portion or its The present invention relates to a pipe joint structure in which a reinforcing cylinder is fitted in a region up to the vicinity.
[0002]
[Prior art]
In this type of pipe joint structure, even if an external force (tensile force in the direction of the tube axis) in the direction of separation acts on the receiving pipe part and the insertion pipe part due to an earthquake or uneven settlement, etc. Since the retaining member is displaced to the reduced diameter side by the cam means as the relative separation movement of the tube portion and the insertion tube portion in the axial direction of the tube axis, the retaining member bites deeper into the outer peripheral surface of the insertion tube portion. As a result, the separation resistance between the receiving tube portion and the insertion tube portion increases.
[0003]
Moreover, since the insertion tube is made of a synthetic resin such as polyethylene, which has superior elongation and bending properties in the direction of the tube axis compared to metals such as cast iron, the tube shaft is caused by earthquakes and uneven settlement. External forces such as tensile force and bending moment in the core direction can be absorbed by utilizing the elongation characteristics and the bending characteristics of the insertion tube section itself.
[0004]
Furthermore, even if the tightening force acting on the synthetic resin insertion tube portion increases with the displacement of the retaining member toward the reduced diameter side, this increased tightening force is applied to the reinforcing cylinder fitted inside the insertion tube portion. Therefore, deformation of the insertion tube portion inward in the radial direction due to the tightening force of the retaining member can be suppressed.
[0005]
Therefore, the synergistic effect of the increase in the detachment resistance and the external force absorption action by the insertion pipe part and the deformation suppression action in the radial direction of the insertion pipe part can enhance the function of preventing the detachment of the insertion pipe part from the receiving pipe part. It is.
[0006]
However, in order to suppress the displacement of the reinforcing cylinder due to vibration or impact during the assembly operation or the flow velocity of the transport fluid, for example, as disclosed in Japanese Utility Model Publication No. 5-9582, etc., The outer diameter of the inner tube portion of the reinforcing cylinder inserted into the insertion tube portion is made larger than the inner diameter of the insertion tube portion over the entire area in the tube axis direction, and the reinforcing cylinder body is inserted. When press-fitted and fixed in the pipe, the frictional resistance between the inner peripheral surface of the insertion tube and the outer peripheral surface of the reinforcing cylinder becomes strong during press-fitting, and the reinforcing cylinder is press-fitted into the insertion pipe by human operation. In this case, a large amount of labor and time are required for the press-fitting work, and when the reinforcing cylinder is press-fitted into the insertion tube portion using mechanical force, there is a drawback that the press-fitting device tends to be large.
[0007]
In particular, the longer the fitting length in the tube axis direction of the reinforced cylindrical body that is press-fitted into the insertion tube part, the easier it is to cause a decrease in the press-fitting work efficiency. In this case, since the dimensional tolerance on the inner diameter side is larger than that of the cast-iron insertion tube portion, the outer diameter dimensional tolerance in the inner tube portion of the reinforcing cylinder is larger, and the inner diameter of the insertion tube portion is larger. When the dimensional tolerances are shifted to the small diameter side, the pressure input of the reinforcing cylindrical body to the insertion pipe portion is remarkably increased, and the above-mentioned defects are further facilitated.
[0008]
Therefore, the applicant of the present application is configured to make the outer diameter of the inner fitting cylinder portion of the reinforcing cylinder fitted into the insertion tube portion smaller than the inner diameter of the insertion tube portion as a method of solving the above-mentioned drawbacks. A plurality of locations in the circumferential direction of the reinforcing cylindrical body, and at a portion corresponding to the distal end side of the insertion tube portion at the time of internal fitting, are positioned to protrude outward in the radial direction from the inner peripheral surface of the insertion tube portion, In addition, a pipe joint structure has been developed in which a retaining piece that is elastically deformed radially inward as it is inserted into the insertion pipe portion is integrally formed in a curved state (see, for example, Japanese Patent Application Laid-Open No. 11-287368).
[0009]
[Problems to be solved by the invention]
In the pipe joint structure described above, even if there is a gap between the inner peripheral surface of the insertion pipe portion and the outer peripheral surface of the inner fitting cylinder portion of the reinforcing cylinder fitted therein, an earthquake, uneven settlement, etc. When the retaining member is displaced to the reduced diameter side by the cam means due to the relative separation between the receiving tube portion and the insertion tube portion due to external force, or the retaining member is reduced by the cam means by the manual operation. If the inner peripheral surface of the insertion tube portion is pressed against the outer peripheral surface of the inner fitting tube portion of the reinforcing tube body, the deformation of the insertion tube portion in the radially inward direction can be effectively suppressed. Reinforcing cylindrical body with respect to the insertion tube portion by finding out that the outer diameter of the inner fitting tube portion of the reinforcing tube body is smaller than the inner diameter of the insertion tube portion within the range where the deformation suppressing effect is obtained. The insertion resistance at the time of internal fitting work can be reduced.
[0010]
In addition, in a state where the inner fitting cylinder portion of the reinforcing cylinder body is fitted in a predetermined position in the insertion tube portion, the retaining portion formed in the reinforcement cylinder body is brought into contact with the inner peripheral surface of the insertion tube portion. Since the elastically deformed inward in the radial direction and the retaining part is pressed against the insertion tube by its elastic restoring force, frictional resistance is generated, so vibration or shock during assembly work or flow velocity of transport fluid etc. The resulting displacement of the reinforcing cylinder can be suppressed.
[0011]
However, in the conventional pipe joint structure, the length in the tube axis direction of each retaining piece and the projecting allowance outward in the radial direction are formed uniformly, and the same portion of the curved portion of each retaining piece Is configured to contact the distal end corner of the inner peripheral surface of the insertion tube portion. A force was generated, and the effect of preventing the detachment of the reinforcing cylindrical body was reduced accordingly.
[0012]
Further, in order to increase the catching force of each retaining piece with respect to the tip side corner of the inner peripheral surface of the insertion tube part, it is conceivable to increase the protrusion margin of each retaining piece radially outward. The curved portion of the retaining piece is hardly elastically deformed inward in the radial direction, and there is a problem that much labor is required for mounting the reinforcing cylinder on the insertion tube portion.
[0013]
The present invention has been made in view of the above-described actual situation, and its main problem is to insert the reinforcing cylinder while facilitating the mounting operation of the reinforcing cylinder with simple and inexpensive modifications to the retaining pieces. It is in the point which provides the pipe joint structure which can improve the fall prevention effect of the reinforcement cylinder with which the pipe part was mounted | worn.
[0014]
[Means for Solving the Problems]
  According to a first aspect of the present invention, there is provided a structure between the outer peripheral surface of the synthetic resin insertion tube portion inserted and connected to the receiving tube portion and the inner peripheral surface of the receiving tube portion, or the insertion tube portion. A retaining member that can bite into the outer peripheral surface of the insertion tube portion between the inner peripheral surface of the press ring that is fixedly connected to the receiving tube portion from the tube axis direction and the outer peripheral surface of the insertion tube portion in a state where it is externally mounted. And a cam means for displacing the retaining member to the reduced diameter side in accordance with the relative detachment movement of the receiving tube portion and the insertion tube portion, and at least the retaining member bites in from the distal end portion in the insertion tube portion. Reinforcing the reinforcing cylinder in the area corresponding to the location or the area up to the vicinity,The outer diameter of the inner tube portion of the reinforcing cylinder is configured to be smaller than the inner diameter of the insertion tube portion. A retaining piece is formed that protrudes outward from the tube and elastically deforms radially inward as it is inserted into the insertion tube.A pipe joint structure,
  Form slits opened in the end face of the base end portion corresponding to the distal end side of the insertion tube portion of the reinforcing cylindrical body, and each piece located between the adjacent slits on the same circumferential line Forming the retaining piece by bending outward in the radial direction at the same time, and configuring the length in the tube axis direction from the bending position to the tip of the retaining piece to a plurality of lengths,Contact positions of a plurality of retaining pieces with respect to the insertion tube portionDifferent in the tube axis directionIn the point.
[0015]
According to the above characteristic configuration, among the retaining pieces formed at a plurality of locations in the circumferential direction of the reinforcing cylinder, the retaining piece whose contact position with respect to the insertion tube portion is located closest to the distal end side of the insertion tube portion is inserted. Under the condition that it is in contact with the tip side corner of the inner peripheral surface of the pipe part, the other retaining pieces will come into contact with the inner peripheral surface of the insertion pipe part in the inserted state. Due to the contact between the retaining piece in contact with the inner peripheral surface of the insertion tube and the radially inward direction of the retaining piece due to contact with the corner on the tip of the inner peripheral surface of the insertion tube Due to the elastic deformation, even if a component force in the pull-out direction is generated in the reinforcing cylinder, the pull-out movement of the reinforcing cylinder can be suppressed.
[0016]
In addition, when the reinforcing cylinder is inserted into the insertion tube portion, since the elastic deformation start timing of the plurality of retaining pieces radially inward is shifted, compared with the case where the plurality of retaining pieces are simultaneously elastically deformed. Further, it is possible to reduce the insertion resistance during the internal fitting operation of the reinforcing cylinder.
[0017]
Therefore, the mounting operation of the reinforcing cylinder can be facilitated with a simple and inexpensive modification that makes the contact positions of the plurality of retaining pieces with respect to the insertion tube portion at least two locations in the tube axis direction. Since the effect of preventing the reinforcement cylinder attached to the insertion tube portion from coming off can be enhanced, the displacement of the reinforcement cylinder caused by vibration or impact during the assembly operation or the flow velocity of the transport fluid is suppressed. Can do.
[0020]
  Of the present inventionClaim 2The characteristic configuration of the pipe joint structure according toThe circumferential width of the retaining piece having a small length in the tube axis direction is configured to be smaller than the circumferential width of the retaining piece having a large length in the tube axis direction.In the point.
[0021]
According to the above-described characteristic configuration, for example, when the circumferential width of each retaining piece is configured to be the same, or the retaining piece whose contact position with respect to the insertion tube portion is located on the insertion distal end side of the reinforcing cylindrical body Compared to the case where the circumferential width is larger than the circumferential width of the retaining piece that contacts the distal end side of the insertion tube part, the internal fitting operation of the reinforcing cylinder to the insertion tube part Can be efficiently and easily performed with less effort.
[0022]
  Of the present inventionClaim 3The characteristic structure of the pipe joint structure according to is that both side edges in the circumferential direction of the retaining piece are bent so that the edges protrude radially outward.
[0023]
According to the above characteristic configuration, the retaining piece formed by bending at a plurality of locations in the circumferential direction of the reinforcing cylinder as the internally fitting cylinder of the reinforcing cylinder is fitted into a predetermined position in the insertion tube. The retaining pieces are pressed against each other while being elastically deformed radially inward by contact with the inner peripheral surface of the insertion tube, and at this time, the edges formed on both circumferential edges of each retaining piece are inserted. Since it will bite into the inner peripheral surface of the pipe part, it is possible to more effectively suppress the displacement of the reinforcing cylinder caused by vibration or impact during the assembly operation or the flow velocity of the transport fluid.
[0024]
Further, since the edge of the retaining piece is protruded radially outward by bending the retaining piece, for example, the inner fitting cylinder portion of the reinforcing cylinder is formed in the insertion tube portion on the outer peripheral surface of the retaining piece. Compared to the case where a dedicated biting part that protrudes into the inner peripheral surface of the insertion tube part is protruded as it is fitted into the predetermined position, the manufacturing cost of the reinforcing cylinder including the biting part is reduced. Cost reduction can be achieved.
[0025]
  Of the present inventionFeatures according to claim 4The configuration isThe outer diameter of the inner tube portion of the reinforcing cylinder fitted into the insertion tube portion made of synthetic resin is configured to be smaller than the inner diameter of the insertion tube portion. Reinforcement for the insertion tube part, which is formed to protrude from the inner peripheral surface of the insertion tube part radially outward and to form a retaining piece that elastically deforms radially inward as the tube is inserted into the insertion tube part. A cylinder,
  Form slits opened in the end face of the base end portion corresponding to the distal end side of the insertion tube portion of the reinforcing cylindrical body, and each piece located between the adjacent slits on the same circumferential line The retaining piece is formed by bending outward in the radial direction at the same time, and the length in the tube axis direction from the bending position to the tip of the retaining piece is configured to be a plurality of lengths, and the insertion The contact positions of multiple retaining pieces with respect to the pipe are different in the tube axis direction.In the point.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
1 to 6 show that an insertion pipe portion 2 on one end side of a polyethylene water pipe P which is an example of a synthetic resin fluid transport pipe is sealed in a receiving pipe portion 1 of a joint body A made of cast iron. The pipe joint structure of the present invention for insertion connection is shown, and two annular grooves 1A and 1B having different groove widths in the tube axis X direction are formed on the inner peripheral surface 1a of the receiving pipe portion 1, In the first annular groove 1A having a small groove width located on the receiving side of the receiving tube portion 1, the space between the inner peripheral surface 1a of the receiving tube portion 1 and the outer peripheral surface 2a of the insertion tube portion 2 is sealed. The first elastic sealing material 3 is mounted and the outer circumferential surface 2a of the insertion tube portion 2 inserted and connected to the receiving tube portion 1 is bitten in the second annular groove 1B having a large groove width located on the back side. An example of a retaining member that can be inserted, made of a synthetic resin (for example, polyacetal) or metal formed in a substantially C-shape that can be elastically reduced in diameter and deformed The retaining ring 4 (for example, stainless steel) and the inner peripheral surface 1a of the receiving tube portion 1 and the outer peripheral surface 2a of the insertion tube portion 2 are sealed at a position behind the retaining ring 4. The second elastic sealing material 5 is attached.
[0028]
As shown in FIG. 1 and FIG. 6, the receiving tube portion 1 and the insertion tube portion are formed on the inner peripheral surface portion located in the second annular groove 1 </ b> B of the inner peripheral surface 1 a of the receiving tube portion 1. The retaining ring 4 is displaced toward the reduced diameter side in accordance with the relative disengagement movement in the tube axis X direction with respect to 2, that is, the cam that deforms the retaining ring 4 against its elastic restoring force. A taper-shaped cam surface 6 is formed as a means, and at least a region corresponding to the biting action location of the retaining ring 4 from the tip in the insertion tube portion 2 or the vicinity thereof (in the first embodiment, In the insertion tube portion 2, a region slightly longer than the tube portion inserted into the receiving tube portion 1) is radially inward of the insertion tube portion 2 due to the diameter reduction deformation of the retaining ring 4. A stainless steel (metal) reinforcing cylinder 7 that suppresses deformation is fitted inside.
[0029]
Among the reinforcing cylinders 7, the outer diameter D1 of the inner fitting cylinder part 7A fitted into the insertion pipe part 2 is configured to be smaller than the inner diameter D2 of the insertion pipe part 2. Specifically, the insertion pipe part 2 The inner diameter D2 is slightly smaller than the minimum inner diameter D2 within the tolerance range, and the distal end portion 7d of the reinforcing cylinder 7 is formed in a tapered shape having a smaller diameter toward the distal end side.
[0030]
Furthermore, the portion of the reinforcing cylinder 7 corresponding to the distal end portion of the insertion tube portion 2 at the time of internal fitting or the vicinity thereof (in this embodiment, the insertion tube is fitted in a predetermined position in the insertion tube portion 2). The proximal end portion corresponding to the distal end portion of the portion 2 is located so as to protrude outward in the radial direction from the inner peripheral surface 2c of the insertion tube portion 2 and has a diameter as it is inserted into the insertion tube portion 2. A retaining portion 7B that is elastically deformed inward in the direction is formed.
[0031]
  As shown in FIGS. 2 and 3, the retaining portion 7 </ b> B is a base end portion of the reinforcing cylinder 7 and at four locations in the circumferential direction thereof.With the end face openIt is composed of retaining pieces 7a and 7b that are elastically deformable radially inward and formed by bending a portion located between adjacent V-shaped slits 7e formed radially outward.
[0032]
Of the retaining pieces 7a, 7b, the length L1 in the tube axis direction of the two first retaining pieces 7a that are located every other in the circumferential direction is set to the other two second retaining pieces. 7b is configured to be smaller than the length L2 in the tube axis direction, and the bending positions of both the first retaining pieces 7a and the second retaining pieces 7b are the same through the lowest position of the slit 7e. The contact position (locking position) of the first retaining piece 7a and the contact position (locking position) of the second retaining piece 7b with respect to the inner peripheral surface 2c of the insertion tube portion 2 are configured on a circumferential line. Are different in the tube axis direction.
[0033]
Of the retaining pieces 7a and 7b, the circumferential width W2 of the first retaining piece 7a having a small length in the tube axis direction is the same as that of the second retaining piece 7b having a large length in the tube axis direction. It is configured to have a width smaller than the circumferential width W1, and the radial distance (protrusion allowance) from the outer peripheral surface of the inner fitting cylindrical portion 7A to the distal end portion of each retaining piece 7a, 7b, that is, each removal The protruding margins in the radially outward direction at the tip portions of the stopper pieces 7a and 7b are the same.
[0034]
Further, of the retaining pieces 7a and 7b, at least the front end edge of the first retaining piece 7a has an inner periphery of the insertion tube portion 2 due to its elastic restoring force as it is inserted into the insertion tube portion 2. An edge 7c pressed against the surface 2c is formed.
[0035]
On the inner peripheral surface of the retaining ring 4, a number of biting protrusions 4 a that can bite into the outer peripheral surface 2 a of the insertion tube portion 2 are formed, and the outer peripheral surface 4 b of the retaining ring 4 is A tapered surface is formed along the cam surface 6.
[0036]
Further, even when the tapered outer peripheral surface 4b of the retaining ring 4 and the cam surface 6 are not in contact with each other, the biting projection 4a is inserted by the elastic restoring force toward the reduced diameter side of the retaining ring 4 It is configured to slightly bite into the outer peripheral surface 2 a of the tube portion 2, and at the distal end portion of the insertion tube portion 2, a retaining ring 4 is resisted against elastic restoring force as the insertion tube portion 2 is inserted. Thus, a tapered second cam surface 2b for expanding and deforming the diameter is formed.
[0037]
The other end portion of the receiving pipe portion 1 of the joint body A is connected via a bolt 11 and a nut 12 to a flange portion 10 provided on a pipe fitting such as another pipe or a gate valve. The flange portion 13 is integrally formed.
[0038]
And in the state which fitted the internal fitting cylinder part 7A of the reinforcement cylinder 7 over the predetermined area | region in the said insertion pipe part 2, as shown in FIG.1 and FIG.4, the internal peripheral surface of the said insertion pipe part 2 As shown in FIG. 6, even if there is a gap between 2c and the outer peripheral surface of the internal fitting cylinder portion 7A of the reinforcement cylinder 7 fitted therein, as shown in FIG. When the mouth tube portion 1 and the insertion tube portion 2 move relative to each other, the retaining ring 4 is reduced in diameter by the cam surface 6 as the cam means, and accordingly, the insertion tube portion 2 is reduced in diameter radially inward. Then, since the inner peripheral surface 2c of the insertion tube portion 2 is pressed against the outer peripheral surface of the inner fitting tube portion 7A of the reinforcing cylinder 7, the subsequent deformation of the insertion tube portion 2 in the radially inward direction is suppressed. be able to.
[0039]
Furthermore, as shown in FIG. 6, of the retaining pieces 7 a and 7 b integrally formed at a plurality of locations in the circumferential direction of the reinforcing cylinder 7, the contact position with respect to the insertion tube portion 2 is the most distal end side of the insertion tube portion 2. When the second retaining piece 7b located at the end is in contact with the corner on the front end side of the inner peripheral surface 2c of the insertion tube portion 2, the other first retaining pieces 7a In this case, the edge 7c formed at the edge of the first retaining piece 7a is elastically applied to the inner circumferential surface 2c of the insertion tube portion 2. Since it is press-contacted, the retaining action of the first retaining piece 7a in this insertion state and the inner peripheral surface 2c of the insertion tube portion 2 is prevented by the pressure contact (engraving) of the inner peripheral surface 2c of the insertion tube portion 2. The second retaining piece 7b is elastically deformed inward in the radial direction due to the contact with the tip side corner, so that the reinforcing cylinder 7 can be pulled out in the direction of withdrawal. There also occurs, it is possible to suppress the movement escape reinforcing cylinder 7.
[0040]
In addition, when the reinforcing cylinder 7 is inserted into the insertion tube portion 2, the elastic deformation start timing inward in the radial direction of the plurality of retaining pieces 7a, 7b is shifted, that is, the diameter of the first retaining piece 7a. Since the elastic deformation start time inward in the direction and the elastic deformation start time inward in the radial direction of the second retaining piece 7b deviate from each other, compared with the case where the plurality of retaining piece pieces 7a and 7b are elastically deformed simultaneously. Thus, it is possible to reduce the insertion resistance during the fitting operation of the reinforcing cylinder 7.
[0041]
[Second Embodiment]
7 and 8, the insertion pipe portion 2 of a polyethylene water pipe P, which is an example of a synthetic resin fluid transport pipe, is inserted and connected to the receiving pipe portion 1 of the joint body A made of cast iron in a sealed state. Another embodiment of the pipe joint structure is shown, and the insertion tube portion 2 is made of synthetic rubber capable of sealing between the inner peripheral surface 1a of the receiving tube portion 1 and the outer peripheral surface 2a of the insertion tube portion 2 (for example, , Styrene-butadiene rubber) and a cast iron push ring 21 that can be compressed into a sealed state (watertight state) by pressing the elastic seal 20 from the tube axis X direction. Fastening means 22 is provided to fasten and connect 21 and the receiving tube portion 1 from the tube axis X direction.
[0042]
Between the inner peripheral surface 21a of the push ring 21 and the outer peripheral surface 2a of the insertion tube portion 2, it is an example of a retaining member that can bite into the outer peripheral surface 2a of the insertion tube portion 2, and is elastic in the tube axis X direction. And a retaining ring 4 made of a synthetic resin (for example, polyacetal) or metal (for example, stainless steel) formed in a substantially C-shape that can be reduced in diameter, and an inner peripheral surface of the press ring 21 21a includes displacement of the retaining ring 4 toward the reduced diameter side in accordance with the relative proximity movement of the presser wheel 21 and the receiving tube portion 1 accompanying the tightening operation of the fastening means 22, that is, the retaining ring 4 is This is an example of cam means for reducing the diameter against the elastic restoring force, and a tapered cam surface 6 having a larger diameter toward the receiving tube portion 1 side is formed.
[0043]
Between the elastic seal material 20 and the press ring 21 and the retaining ring 4 facing each other in the tube axis X direction, only the elastic seal material 20 is pressed and compressed in the first half of the tightening operation by the fastening means 22. Sequential actuating means 23 for reducing the diameter of the retaining ring 4 against the elastic restoring force by the cam surface 6 in the tightening operation after the elastic sealing member 20 is in the set compression state. Is provided.
[0044]
Further, in the state where the retaining ring 4 slightly bites into the outer peripheral surface 2a of the insertion tube portion 2, an external force (tube axis core) in the detaching direction is applied to the insertion tube portion 1 and the insertion tube portion 2 that are inserted and connected. When the receiving tube portion 1 and the insertion tube portion 2 move relative to each other due to a tensile force in the X direction), the tapered outer peripheral surface 4b of the retaining ring 4 is pressed against the cam surface 6 accordingly. The diameter of the retaining ring 4 is reduced and the biting protrusion 4a of the retaining ring 4 is further bitten into the outer peripheral surface 2a of the insertion tube portion 2.
[0045]
And the area | region from the front-end | tip in the said insertion pipe part 2 to the site | part equivalent to at least the biting effect | action part of the retaining ring 4 or its vicinity (in the said 2nd Embodiment, the receiving pipe | tube among the said insertion pipe parts 2) (In the region slightly longer than the sum of the length of the tube portion inserted into the portion 1 and the length in the tube axis direction of the push ring 21), the radially inward of the insertion tube portion 2 due to the diameter reduction deformation of the retaining ring 4 A reinforcing cylinder 7 made of stainless steel (made of metal) that suppresses deformation to the inside is fitted.
[0046]
Among the reinforcing cylinders 7, the outer diameter D1 of the inner fitting cylinder part 7A fitted into the insertion pipe part 2 is configured to be smaller than the inner diameter D2 of the insertion pipe part 2. Specifically, the insertion pipe part 2 The distal end portion 7d of the reinforcing cylindrical body 7 is formed in a tapered shape having a smaller diameter toward the distal end side while being configured to be slightly smaller than the minimum inner diameter D2 within the dimensional tolerance range of the inner diameter D2.
[0047]
Furthermore, the portion of the reinforcing cylinder 7 corresponding to the distal end portion of the insertion tube portion 2 at the time of internal fitting or the vicinity thereof (in this embodiment, the insertion tube is fitted in a predetermined position in the insertion tube portion 2). The proximal end portion corresponding to the distal end portion of the portion 2 is located so as to protrude outward in the radial direction from the inner peripheral surface 2c of the insertion tube portion 2 and has a diameter as it is inserted into the insertion tube portion 2. A retaining portion 7B that is elastically deformed inward in the direction is formed.
[0048]
The retaining portion 7B is a base end portion of the reinforcing cylinder 7 and a portion located between adjacent V-shaped slits 7e formed at four locations in the circumferential direction is bent radially outward. The retaining pieces 7a and 7b are elastically deformable radially inwardly formed.
[0049]
Of the retaining pieces 7a, 7b, the length L1 in the tube axis direction of the two first retaining pieces 7a that are located every other in the circumferential direction is set to the other two second retaining pieces. 7b is configured to be smaller than the length L2 in the tube axis direction, and the bending positions of both the first retaining pieces 7a and the second retaining pieces 7b are the same through the lowest position of the slit 7e. The contact position (locking position) of the first retaining piece 7a with respect to the inner peripheral surface 2c of the insertion tube portion 2 and the contact position (locking position) of both the second retaining pieces 7b are configured on a circumferential line. ) In the tube axis direction.
[0050]
Of the retaining pieces 7a and 7b, the circumferential width W2 of the first retaining piece 7a having a small length in the tube axis direction is the same as that of the second retaining piece 7b having a large length in the tube axis direction. While being configured to have a width smaller than the circumferential width W1, the protruding margins of the respective retaining pieces 7a, 7b in the radially outward direction are configured to be the same.
[0051]
Further, of the retaining pieces 7a and 7b, at least an end edge of the first retaining piece 7a having a short length in the tube axis direction is elasticized as it is inserted into the insertion tube portion 2. An edge 7c that is pressed against the inner peripheral surface 2c of the insertion tube portion 2 by a restoring force is formed.
[0052]
As shown in FIG. 8, the sequential actuating means 23 is provided between the retaining ring 4 and the elastic seal material 20, as the push ring 21 and the receiving pipe portion 1 move relative to each other. Stainless steel provided with a first pressing surface 24a for pressing and compressing the retaining ring 4 from the tube axis X direction, and a second pressing surface 24b capable of pressing the retaining ring 4 toward the cam surface 6 side of the press wheel 21 from the tube axis X direction. An annular intermediate pressing body 24 made of a metal such as steel or a synthetic resin is provided, and the pressing wheel 21 extends over a portion of the intermediate pressing body 24 and the inner peripheral surface of the pressing wheel 21 which are opposed or substantially opposed in the radial direction. Tube shaft of the cam surface 6 of the presser wheel 21 and the second pressing surface 24b of the intermediate pressing body 24 until the elastic sealing material 20 is in a set compression state as the relative proximity movement between the receiving tube portion 1 and the receiving tube portion 1 proceeds. The retaining ring 4 that is not biting in the facing distance in the core X direction is shrunk. When the elastic sealing material 20 is in a set compression state, the gap is sheared between the outer peripheral surface of the intermediate pressing body 24 and the inner peripheral surface 21a of the presser wheel 21 when the elastic sealing material 20 is in a set compression state. The restriction is released, that is, an interval restricting member (such as a copper alloy or an aluminum alloy) that allows the cam surface 6 of the press wheel 21 and the second pressing surface 24b of the intermediate pressing body 24 to move relatively close to each other in the tube axis X direction. A metal headed shear pin) 25 is provided.
[0053]
The fastening means 22 includes both bolt insertion holes that face each other in the direction of the tube axis X out of the bolt insertion holes 27 of the connection flange portion 26 of the receiving pipe portion 1 and the bolt insertion holes 29 of the connection protrusion 28 of the push ring 21. 27 and 29, and is composed of a T-shaped bolt 22A and a nut 22B.
[0054]
In addition, since the detail of the said reinforcement cylinder 7 and the retaining ring 4 is the same as 1st Embodiment, it attaches | subjects the same code | symbol to the same structure, and abbreviate | omits the description.
[0055]
[Third Embodiment]
In each of the above-described embodiments, the retaining portion 7B is a portion located between the base end portion of the reinforcing cylinder 7 and adjacent to the V-shaped slits 7e formed at four locations in the circumferential direction. 9 is formed of retaining pieces 7a and 7b that are elastically deformed radially inwardly formed by bending outward in the direction, but as shown in FIG. A plurality of peripheral portions of the intermediate portion displaced toward the center side in the core (tube axis) direction are formed by punching radially outward, and a plurality of punches that can be elastically deformed radially inward. The retaining portion 7B may be configured by the retaining pieces 7a and 7b.
[0056]
Further, out of the retaining pieces 7a and 7b, the length L1 in the tube axis direction of the two first retaining pieces 7a that are alternately arranged in the circumferential direction is set to the other two second removed pieces. The stopper piece 7b is configured to be smaller than the length L2 in the tube axis direction, and the bending positions of both the first stopper pieces 7a and the second stopper pieces 7b are set to the lowest position of the slit 7e. Constructed on the same circumferential line that passes through, the contact position (locking position) of the first retaining piece 7a with respect to the inner peripheral surface 2c of the insertion tube portion 2 and the contact position (engagement position) of both the second retaining pieces 7b The stop position is different in the tube axis direction.
In addition, since the other structure is the same as the structure demonstrated in 1st Embodiment, the same number is attached to the same structure location as 1st Embodiment, and the description is abbreviate | omitted.
[0057]
[Fourth Embodiment]
In each of the above-described embodiments, the distance (protrusion allowance) in the radial direction from the outer peripheral surface of the internal fitting cylindrical portion 7A to the distal end portion of each retaining piece 7a, 7b, that is, the distal end of each retaining piece 7a, 7b. Although the protrusion margin to the radially outward direction in the portion is the same, as shown in FIG. 10, the protrusion margin in the radially outward direction at the distal end portion of the first retaining piece 7a is the second retaining piece. You may comprise larger than the protrusion margin to radial direction outward in the front-end | tip part of 7b.
[0058]
In the fourth embodiment, as in the first embodiment, the length L1 of the first retaining piece 7a in the tube axis direction is set to the length L1 of the second retaining piece 7b in the tube axis direction. Configured to be smaller than the length L2, and the folding positions of both the first retaining piece 7a and the second retaining piece 7b are configured on the same circumferential line passing through the lowest position of the slit 7e, The contact position (locking position) of the first retaining piece 7a with respect to the inner peripheral surface 2c of the insertion tube portion 2 and the contact position (locking position) of both the second retaining pieces 7b differ in the tube axis direction. Further, the circumferential width W2 of the first retaining piece 7a is smaller than the circumferential width W1 of the second retaining piece 7b.
[0059]
Contrary to the fourth embodiment, the radially outward protrusion margin at the distal end portion of the second retaining piece 7b is used as the radially outward projection margin at the distal end portion of the first retaining piece 7a. It may be configured larger than the cost.
[0060]
[Fifth Embodiment]
In each of the above-described embodiments, the retaining portion 7B is composed of retaining pieces 7a and 7b that are elastically deformable radially inward and formed by bending a plurality of circumferential portions of the reinforcing cylinder 7 radially outward. The outer peripheral surfaces of the retaining pieces 7a and 7b are formed in an arc shape. However, as shown in FIG. 11, both circumferential edges of the retaining pieces 7a and 7b along the slit 7e The second edge 7f may be bent so as to protrude outward in the direction.
[0061]
According to this embodiment, as the internal fitting cylindrical portion 7A of the reinforcing cylindrical body 7 is internally fitted at a predetermined position in the insertion tube portion 2, it is bent at a plurality of locations in the circumferential direction of the reinforcing cylindrical body 7. The retaining pieces 7a and 7b of the retaining portion 7B are pressed against each other while being elastically deformed radially inward by contact with the inner peripheral surface 2c of the insertion tube portion 2, and at this time, each retaining piece 7a , 7b, the second edges 7f formed on both side edges in the circumferential direction bite into the inner peripheral surface 2c of the insertion tube portion 2, so that vibrations or shocks during the assembly work or the flow of the transport fluid (flow velocity) It is possible to more effectively suppress the displacement of the reinforcing cylinder 7 caused by the above.
[0062]
Moreover, since the second edges 7f of the retaining pieces 7a, 7b are projected radially outward by bending the retaining pieces 7a, 7b, for example, on the outer peripheral surfaces of the retaining pieces 7a, 7b, When the internal fitting cylinder 7A of the reinforcing cylinder 7 is fitted into a predetermined position in the insertion tube portion 2, a dedicated biting portion that protrudes into the inner peripheral surface 2c of the insertion tube portion 2 is formed. Compared to the above, it is possible to reduce the manufacturing cost of the reinforcing cylinder 7 provided with the biting portion.
[0063]
[Other Embodiments]
(1) In each of the above-described embodiments, the joint main body A has been described with an example in which the connecting flange portion is integrally formed on the other end side in the tube axis direction of the receiving pipe portion 1. For example, it may be a joint body A provided with a pair of receiving pipe parts 1 into which the insertion pipe part 2 is inserted and connected separately. Moreover, the receiving pipe part currently formed in the connection port part side of pipe joint instruments, such as a gate valve, may be sufficient.
[0064]
(2) In each of the above-described embodiments, the contact positions (locking positions) of the retaining pieces 7a and 7b with respect to the insertion tube portion 2 are alternately varied in the tube axis direction along the circumferential direction. However, the contact positions of the retaining pieces 7a and 7b may be configured to be alternately changed in the tube axis direction in units of two or more along the circumferential direction.
In the above-described embodiments, two types of retaining pieces 7a and 7b having different contact positions (locking positions) with respect to the insertion tube portion 2 in the tube axis direction are formed. You may comprise from 3 or more types of retaining pieces in which a position (locking position) differs in 3 or more places in a pipe axis direction.
Further, a plurality of types of retaining pieces having different contact positions (locking positions) with respect to the insertion tube portion 2 in the tube axis direction are arranged in the circumferential direction in a state where the contact positions draw a spiral or a V-shape. You may arrange.
In short, it suffices if the contact positions (locking positions) of the plurality of retaining pieces with respect to the insertion tube portion 2 are different at least at two locations in the tube axis direction.
[0065]
(3) In the above-described fifth embodiment, the inner fitting cylinder portion 7A of the reinforcing cylinder 7 is bitten by the inner peripheral surface 2c of the insertion tube portion 2 as it is fitted into a predetermined position in the insertion tube portion 2. The biting portion is composed of edges 7f protruding outward in the radial direction formed on both circumferential edges of the retaining pieces 7a, 7b. You may comprise from the processus | protrusion formed in the surface.
[0066]
(4) In each of the above-described embodiments, the reinforcing cylindrical body 7 that suppresses the radially inward deformation of the insertion tube portion 2 due to the reduced diameter deformation of the retaining ring 4 is provided from the distal end in the insertion tube portion 2. Although the internal fitting was carried out over the wide area | region beyond the biting action location of the retaining ring 4, this reinforcement cylinder 7 is the biting action location of the retaining ring 4 at least from the front-end | tip in the insertion pipe part 2, or its vicinity. It suffices if it is fitted over the corresponding region or the region up to the vicinity thereof.
[0067]
(5) In the above-described fourth embodiment, the retaining pieces 7a and 7b are composed of two types having different projecting allowances in the radially outward direction at the tip portions thereof. You may comprise from three types of retaining pieces in which protrusion margins differ in three or more.
[0068]
(6) In each of the above embodiments, the reinforcing cylinder 7 is manufactured from stainless steel, which is an example of a metal, but may be manufactured from a synthetic resin.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a first embodiment of a pipe joint structure according to the present invention.
FIG. 2 is a perspective view of a reinforcing cylinder.
FIG. 3 is a front view of a reinforcing cylinder.
FIG. 4 is a longitudinal sectional view in the middle of internal fitting between an insertion tube portion and a reinforcing cylinder.
FIG. 5 is a longitudinal sectional view of the insertion tube portion and the reinforcing cylinder body when the inner fitting is completed.
FIG. 6 is a longitudinal sectional view when the receiving tube portion and the insertion tube portion are moved relatively apart from each other.
FIG. 7 is a longitudinal sectional view showing a second embodiment of the pipe joint structure of the present invention.
FIG. 8 is an enlarged cross-sectional view of the main part during assembly.
FIG. 9 is a longitudinal sectional view of a reinforcing cylinder showing a third embodiment of the pipe joint structure of the present invention.
FIG. 10 is a front view of a reinforcing cylinder showing a fourth embodiment of the pipe joint structure of the present invention.
FIG. 11 is a partially cutaway front view of a reinforcing cylinder showing a fifth embodiment of the pipe joint structure of the present invention.
[Explanation of symbols]
1 Receptacle tube
1a Inner peripheral surface
2 Insertion tube
2a Outer peripheral surface
2c Inner peripheral surface
4 Retaining member (Retaining ring)
6 Cam means (tapered surface)
7 Reinforcing cylinder
7A Internal fitting cylinder
7a retaining piece
7b retaining piece
7c edge
21 Press wheel
21a Inner peripheral surface
X Tube core

Claims

A pipe is formed between the outer peripheral surface of the synthetic resin insertion tube portion inserted into and connected to the receiving tube portion and the inner peripheral surface of the receiving tube portion, or in a state where the outer tube is mounted on the insertion tube portion. A retaining member capable of biting into the outer peripheral surface of the insertion tube portion is provided between the inner peripheral surface of the press ring fixedly connected from the axial direction and the outer peripheral surface of the insertion tube portion, and the receiving tube portion and the insertion tube are provided. A cam means for displacing the retaining member to the reduced diameter side in accordance with relative detachment movement with respect to the portion is provided, and at least a region corresponding to or near the portion where the retaining member bites into the insertion tube portion A reinforcing cylinder is internally fitted to the inner cylinder, and an outer diameter of the inner fitting cylinder of the reinforcing cylinder is smaller than an inner diameter of the insertion pipe. It protrudes radially outward from the inner peripheral surface of the part, and elastically deforms radially inward as it is inserted into the insertion tube part A pipe joint structure is formed with stopping piece,
Form slits opened in the end face of the base end portion corresponding to the distal end side of the insertion tube portion of the reinforcing cylindrical body, and each piece located between the adjacent slits on the same circumferential line The retaining piece is formed by bending outward in the radial direction at the same time, and the length in the tube axis direction from the bending position to the tip of the retaining piece is configured to be a plurality of lengths, and the insertion A pipe joint structure in which the contact positions of a plurality of retaining pieces with respect to the pipe part are varied in the pipe axis direction .

Of the retaining pieces, the circumferential width of the retaining piece having a small length in the tube axis direction is configured to be smaller than the circumferential width of the retaining piece having a large length in the tube axis direction. The pipe joint structure according to claim 1 .

The pipe joint structure according to claim 1 or 2, wherein both circumferential edges of the retaining piece are bent so that the edges protrude radially outward.

The outer diameter of the inner tube portion of the reinforcing cylinder fitted into the synthetic resin insertion tube portion is configured to be smaller than the inner diameter of the insertion tube portion. Reinforcement for the insertion tube part that protrudes radially outward from the inner peripheral surface of the insertion tube part and forms a retaining piece that elastically deforms radially inward as it is inserted into the insertion tube part A cylinder,
Form slits opened at the end face of the base end portion corresponding to the distal end side of the insertion tube portion of the reinforcing cylindrical body, and each piece located between adjacent slits on the same circumferential line. The retaining piece is formed by bending outward in the radial direction at the same time, and the length in the tube axis direction from the bending position to the tip of the retaining piece is configured into a plurality of lengths, and the insertion A reinforcing cylinder for an insertion tube portion in which the contact positions of a plurality of retaining pieces with respect to the tube portion are varied in the tube axis direction.