JP4293488B2

JP4293488B2 - Pipe joint structure and connection method

Info

Publication number: JP4293488B2
Application number: JP24512299A
Authority: JP
Inventors: 伸行藤沢; 秀樹河村
Original assignee: ライト工業株式会社
Priority date: 1999-08-31
Filing date: 1999-08-31
Publication date: 2009-07-08
Anticipated expiration: 2019-08-31
Also published as: JP2001065749A

Description

【０００１】
【発明の属する技術分野】
本発明は、短時間で容易に接続でき、かつ狭隘部での作業性を向上させた管の継手構造および接続方法に関する。
【０００２】
【従来の技術】
従来、管の接続方法には、ネジ方式、溶接方式、加締方式および形状記憶合金方式等の方式があり、それぞれの方式において管の継手構造も異なっている。以下にそれぞれの方式について詳述する。
【０００３】
（ネジ方式）
ネジ方式は、先行管の後端と後続管の先端のそれぞれ管本体に雄ネジと雌ネジを設けて管本体同士を螺合させる方式と、カップリングジョイントを使用する方式がある。前者の場合、曲線管本体を振り回すためシールドトンネル内等の狭隘部での施工には不向きである。後者のカップリングジョイント式の場合は、接続後の継手部が凹凸となり、やはり狭隘部での施工には不向きである。
【０００４】
（溶接方式）
溶接方式は、管の形状に関係なく接続可能なため接続方法として広く用いられている。しかし、溶接方式では、接続部が熱よって生じるひずみによって外面に曲がったり、面内に折れたりしやすい。また、溶接部の肉盛りによる段差が管内部に生じた場合には、管内を輸送する輸送物の障害となる。さらに管の溶接は、三次元的に接続の精度を捉えながら作業するためシールドトンネル内等の狭隘部での施工には向いていない。
【０００５】
（加締方式）
加締方式は、予め接続継手を溶接し、溶接面をきれいに磨いて段差のないようにした管を施工現場で突き合わせ、継手部に金属カラーをプレス装置で圧着し、管同士を接続する方法である。接続継手は工場内で溶接されるため、精度を保つことができ、面外ねじれや折れが生じない。しかしながら、大きい継手強度を得るためには高い圧力をかけられる大きなプレス装置が必要となるため、小径のシールドトンネル内等の狭隘部での施工では作業性が悪い。
【０００６】
（形状記憶合金方式）
形状記憶合金方式は、予め接続継手を溶接し、溶接面をきれいに磨いて段差のないようにした管を施工現場で突き合わせ、この継手部に形状記憶合金製のカラーを装着した後、電熱器で加温してカラーのリング径を縮小させ管同士を圧着する方法である。この方式では、加締方式と同様に、接続継手が工場で溶接されるため、精度を保つことができ面外ねじれや折れが生じない。さらに設備は小型で狭隘箇所での作業が可能である。しかし、形状記憶合金製のカラーが非常に高価であるという欠点を有する。
【０００７】
【発明が解決しようとする課題】
本発明は、上記した従来技術における問題点を解決し、先行管と後続管とを短時間で容易に接続でき、かつ狭隘部での作業性を向上させた管の継手構造および接続方法を提供することにある。
【０００８】
【課題を解決するための手段】
【０００９】
上記課題を解決した請求項１記載の発明は、第１管と第２管とを連結する継手構造において、先端部外周に雄ネジが形成された第１管と、先端部外面に外径が拡大する拡外径段部を有する第２管と、内径が縮小する縮内径段部を有し、かつ前記第１管側内面に雌ネジが形成されたカップリングとを備え、前記カップリングは、その縮内径段部が前記拡外径段部より前記第２管の後方側に位置し、前記第２管の端部外周において周方向に回転自在に設けられ、前記カップリングの回転によりその雌ネジと第１管の雄ネジが螺合され、前記第２管はその拡外径段部が前記縮内径段部の存在により前記カップリングからの抜け止めが図られ、前記第２管の外周面に凹段部が形成され、前記カップリングの雌ネジと前記第１管の雄ネジが螺合された状態で、前記凹段部内においてその段差面と前記カップリングの後端面との間に緩み止めリングが被嵌されていることを特徴とする管の継手構造である。
【００１０】
請求項２記載の発明は、前記緩み止めリングは、前記凹段部内に対して被嵌および脱着可能である請求項１記載の管の継手構造である。
【００１１】
請求項３記載の発明は、前記第１管の前記雄ネジより先端側部分と、前記第２管の縮内径段部より先端側部分とが、横断面相欠き継ぎ形状であり、かつその重ね合わせ面が、前記第１管の外径が先窄み、前記第２管の内径が先拡大である請求項１記載の管の継手構造である。
【００１２】
請求項４記載の発明は、前記第１管の内面と前記第２管の内面が面一である請求項１記載の管の継手構造である。
【００１３】
請求項５記載の発明は、前記第１管と前記第２管とを接続したさいに、前記第１管と前記第２管と継手部分の外面が面一となる請求項１記載の管の継手構造である。
【００１４】
請求項６記載の発明は、第１管と第２管とを連結する継手構造において、先端部外周に雄ネジが形成された第１管と、先端部外面に外径が拡大する拡外径段部を有する第２管と、内径が縮小する縮内径段部を有し、かつ前記第１管側内面に雌ネジが形成されたカップリングとを備え、前記カップリングは、その縮内径段部が前記拡外径段部より前記第２管の後方側に位置し、前記第２管の端部外周において周方向に回転自在に設けられ、前記カップリングの回転によりその雌ネジと第１管の雄ネジが螺合され、前記第２管はその拡外径段部が前記縮内径段部の存在により前記カップリングからの抜け止めが図られ、継手部分を除いて、前記第１管および前記第２管は曲がり管であり、前記第１管の前記雄ネジより先端側部分と、前記第２管の縮内径段部より先端側部分とが、横断面相欠き継ぎ形状であり、かつその重ね合わせ面が、前記第１管の外径が先窄み、前記第２管の内径が先拡大であり、前記第１管の重ね合わせ面の周方向の一部に、外径が大きくなった先窄まりの係合凸部が形成され、前記第２管の重ね合わせ面の周方向の一部に、前記係合凸部に対応した形状の係合凹部が形成され、前記係合凸部と係合凹部とは係合される構成としたことを特徴とする管の継手構造である。
【００１５】
【００１６】
請求項７記載の発明は、第１管の先端部外周に雄ネジを形成し、第２管の先端部外面に外径が拡大する拡外径段部を形成し、この第２管に、内径が縮小する縮内径段部を有しかつ前記第１管側内面に雌ネジが形成されたカップリングを、前記縮内径段部が前記拡外径段部より前記第２管の後方側に位置し、かつ前記第２管の端部外周において周方向に回転自在となるように設け、前記カップリングを回転させてその雌ネジと前記第１管の雄ネジを螺合させるとともに、前記第２管はその拡外径段部が前記縮内径段部の存在により前記カップリングからの抜け止めが図られている前記第１管と第２管とが接続され、前記第２管の外周面に凹段部が形成され、前記カップリングの雌ネジと前記第１管の雄ネジが螺合された状態で、前記凹段部内においてその段差面と前記カップリングの後端面との間に緩み止めリングを被嵌することを特徴とする管の接続方法である。
【００１７】
請求項８記載の発明は、前記緩み止めリングを、前記凹段部内に対して被嵌および脱着可能とする請求項７記載の管の接続方法である。
【００１８】
請求項９記載の発明は、前記第１管の前記雄ネジより先端側部分と、前記第２管の縮内径段部より先端側部分とを、横断面相欠き継ぎ形状に形成し、かつその重ね合わせ面を、前記第１管の外径が先窄み、前記第２管の内径が先拡大に形成し、前記第１管の先端側部分を前記第２管の先端側部分に嵌挿して接合し、前記雄ネジと雌ネジとを螺合する請求項７記載の管の接続方法である。
【００１９】
請求項１０記載の発明は、第１管の先端部外周に雄ネジを形成し、第２管の先端部外面に外径が拡大する拡外径段部を形成し、この第２管に、内径が縮小する縮内径段部を有しかつ前記第１管側内面に雌ネジが形成されたカップリングを、前記縮内径段部が前記拡外径段部より前記第２管の後方側に位置し、かつ前記第２管の端部外周において周方向に回転自在となるように設け、前記カップリングを回転させてその雌ネジと第１管の雄ネジを螺合させるとともに、前記第２管はその拡外径段部が前記縮内径段部の存在により前記カップリングからの抜け止めが図られている前記第１管と第２管とが接続され、継手部分を除いて、前記第１管および前記第２管を曲がり管とし、前記第１管の前記雄ネジより先端側部分と、前記第２管の縮内径段部より先端側部分とを、横断面相欠き継ぎ形状に形成し、かつその重ね合わせ面を、前記第１管の外径が先窄み、前記第２管の内径が先拡大となるように形成し、前記第１管の重ね合わせ面の周方向の一部に、外径が大きくなった先窄まりの係合凸部を形成し、前記第２管の重ね合わせ面の周方向の一部に、前記係合凸部に対応した形状の係合凹部を形成し、前記係合凸部と係合凹部とを係合した後に、前記雄ネジと雌ネジとを螺合することを特徴とする管の接続方法である。
【００２０】
【発明の実施の形態】
本発明に係る鋼管の接続継手を図面を参照しながら説明する。
本発明に係る接続継手構造を図１〜３に示す。先端部外周に雄ネジ１１が形成された第１管１０と、先端部外面に外径が拡大する拡外径段部２１を有する第２管２０と、内径が縮小する縮内径段部３１を有し、かつ前記第１管側内面に雌ネジ３２が形成されたカップリング３０とを備えている。
【００２１】
前記カップリング３０は、その縮内径段部３１が前記拡外径段部２１より前記第２管２０の後方側に位置し、かつ前記第２管２０の端部外周において周方向に回転自在に設けられており、前記拡外径段部２１と前記縮内径段部３１の存在により前記第２管２０からの抜け止めが図られている。前記縮内径段部３１および拡外径段部２１は、図示されるようにそれぞれテーパー形状として、それぞれの傾斜面が面接するようにしてもよい。
【００２２】
前記カップリング３０の雌ネジ３２は、第１管１０の雄ネジ１１と螺合するように構成されており、第１管１０の先端部１２と第２管２０の先端部２２とを接合させた状態でカップリング３０を回転させることで管同士が接続される構成とされている。第２管２０の外周面に形成される凹段部２３には、カップリング３０を回転させて前記雄ネジ１１と前記雌ネジ３２とを螺合させた後に、前記凹段部２３内においてその段差面と前記カップリングの後端面との間に緩み止めリング４０が被嵌されている。前記緩み止めリング４０は、ネジが完全に螺合した時点でしかはまらないサイズとされており、緩み止めリング４０の装着状態ではカップリング３０が逆回転して螺合しているネジが緩むことはない。また、緩み止めリング４０は着脱自在とされている。
【００２３】
一方、前記第１管１０の雄ネジ１１より先端側部分１２と、前記第２管２０の前記拡外径段部２１より先端側部分２２とは、横断面相欠き継ぎ形状とされており、管同士がしっかりと接合するように構成されており、接合部の剛性を高めるようになっている。さらにその重ね合わせ面は、前記第１管１０の外径が先窄み、前記第２管２０の内径が先拡大とされており、第１管１０の先端部１２を第２管２０内に挿入しやすいようになっている。逆に、前記第１管の内径を先拡大とし、前記第２管の外径を先窄みとして、第２管の先端部を第１管内に挿入しやすくしてもよい。
【００２４】
また、図１に示されるように、継手構造は、接続状態において第１管１０と第２管２０の外面および内面とも面一となるように、構成されている。
【００２５】
本発明に係る継手構造は、継手部分を除けばどのような管の形状であってもよい。例えば、直線管であってもよいし、図示されるような曲がり管であってもよい。曲がり管を使用する場合は、図示されるように、予め、第１管１０の重ね合わせ面の周方向の一部に、外形が大きくなった先窄まりの係合凸部３３を形成し、第２管２０の重ね合わせ面の周方向の一部に、前記係合凸部３３に対応した形状の係合凹部２４を形成し、前記係合凸部３３と係合凹部２４とが係合されるように構成しておくことで、接続する曲がり管の接合位置を簡単に決定することができる。
【００２６】
本発明に係る、接続継手は以下のようにして形成することができる。
図３に示されるように、外周に雄ネジ１１を有する雄ネジ管１０Ａと、先端部外面に外径が拡大する拡外径段部２１を有するテーパー管２０Ａと、内径が縮小する縮内径段部３１を有し、かつ前記第１管１０側内面に雌ネジ３２が形成されたカップリング３０とを、予め形成しておく。雄ネジ管１０Ａと曲がり管Ａとを溶接することで第１管１０が形成され、カップリング３０をテーパー管２０Ａに挿入した状態でテーパー管２０Ａと曲がり管Ｂとを溶接することで第２管２０が形成されるとともに、カップリング３０が前記第２管２０の先端より抜けないように形成される。また、曲がり管Ａ，Ｂ、テーパー管２０Ａおよび雄ネジ管１０Ａの内面を面一になるように形成すれば内面に凹凸のない継手部が形成される。また、曲がり管Ａ，Ｂ、緩み止めリング４０およびカップリング３０の外形を同径にするなどすれば、管同士を接続した後に、接続部分と曲がり管Ａ、Ｂの外面とが面一となる。溶接後に、それぞれの溶接部Ｗをきれいに磨いて段差のないようにする。これらの溶接作業は施工現場で行なう必要はなく、予め工場など作業がしやすい場所で行なうことができる。
【００２７】
続いて、前記接続継手を使用した管の接続方法を図４〜図６を参照して説明する。第１管１０と第２管２０とを接続位置において、それらの先端を接合させる。次いでこの接合状態で、前記カップリング３０を回転させて前記雄ネジ部１１と雌ネジ部３２とを螺合させる。カップリング３０と第２管２０は前述のとおりカップリングから抜けないように構成されているため、カップリング３０と第１管１０とを連結するだけで必然的に第１管１０と第２管２０とが接続される。カップリング３０を回転させるには、図５に示されるような、前記カップリング３０の外周に設けた凹部３３に係合する凸部５１と、この凸部５１から前記カップリング３０の外周に沿って延在する鎌状の支持部５２と、この支持部５２から、外縁方向に延在する操作部５３とを有するレンチ５０を使用することができる。前記凸部５１と前記凹部３３とを係合させた後に、操作部５３を周方向に引っ張ればカップリング３０を容易に回転させることができる。カップリング３０が動かなくなる位置まで回転させて前記雌ネジ３２と雄ネジ１１とが螺合した後に、第２管２０の外周面に形成された凹段部２３内においてその段差面と前記カップリング３０の後端面との間に緩み止めリング４０を被嵌する。この緩み止めリング４０の装着により、カップリング３０は正逆どちらにも回転できなくなるので接続後に緩むことがなくなる。この緩み止めリング４０を装着すると、図６に示される態様となり、第１管１０と第２管２０との接続は完了する。
【００２８】
【発明の効果】
本発明に係る管の接続継手構造は、短時間で容易に管同士を接続することができ、また継手部に凹凸ができない形状とすることができ狭隘部での施工性に優れる。また継手部分を予め工場内で形成できるため高い精度の継手構造とすることができる。
【図面の簡単な説明】
【図１】継手構造の断面図である
【図２】継手構造の上面図である。
【図３】継手構造の分解斜視図である。
【図４】継手構造の斜視図である。
【図５】カップリングを回転させるレンチを示す図である。
【図６】管の接続後の状態を示す状態図である。
【符号の説明】
１０…第１管、１０Ａ…雄ネジ管、１１…雄ネジ、２０…第２管、２１…拡外径段部、２３…凹段部、３０…カップリング、３１…縮内径段部、３３…凹部、４０…緩み止めリング、５０…レンチ、Ｗ…溶接部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pipe joint structure and a connection method that can be easily connected in a short time and improve workability in a narrow portion.
[0002]
[Prior art]
Conventionally, pipe connection methods include a screw method, a welding method, a caulking method, a shape memory alloy method, and the like, and the joint structure of the pipe is different in each method. Each method will be described in detail below.
[0003]
(Screw method)
There are two types of screw systems: a male screw and a female screw are provided on the pipe body at the rear end of the preceding pipe and the tip of the subsequent pipe, respectively, and a pipe joint is screwed together, and a coupling joint is used. In the former case, the curved pipe main body is swung around, so that it is not suitable for construction in a narrow part such as a shield tunnel. In the case of the latter coupling joint type, the joint part after connection becomes uneven, which is also unsuitable for construction in a narrow part.
[0004]
(Welding method)
The welding method is widely used as a connection method because it can be connected regardless of the shape of the pipe. However, in the welding method, the connection portion is easily bent to the outer surface or broken in the surface due to strain caused by heat. In addition, when a step due to the build-up of the welded portion occurs inside the pipe, it becomes an obstacle to the transported goods transported in the pipe. Furthermore, pipe welding is not suitable for construction in confined areas such as in shield tunnels because it works while capturing the connection accuracy in three dimensions.
[0005]
(Casting method)
The caulking method is a method in which the joints are welded in advance, the welded surfaces are polished and the pipes that have no level difference are butted together at the construction site, the metal collar is crimped to the joints with a press device, and the pipes are connected. is there. Since the connecting joint is welded in the factory, the accuracy can be maintained and no out-of-plane twisting or bending occurs. However, in order to obtain a large joint strength, a large pressing device capable of applying a high pressure is required, so workability is poor in construction in a narrow portion such as in a small-diameter shield tunnel.
[0006]
(Shape memory alloy method)
In the shape memory alloy method, the connection joint is welded in advance, the welded surface is polished and the pipe is made to have no step, and the pipe is matched at the construction site. In this method, the ring diameter of the collar is reduced by heating to crimp the tubes together. In this method, as with the caulking method, the connecting joint is welded at the factory, so that accuracy can be maintained and no out-of-plane twisting or bending occurs. In addition, the equipment is small and can be used in narrow spaces. However, the shape memory alloy collar has the disadvantage of being very expensive.
[0007]
[Problems to be solved by the invention]
The present invention provides a pipe joint structure and a connection method that solve the above-described problems in the prior art, can easily connect a preceding pipe and a subsequent pipe in a short time, and improve workability in a narrow portion. There is to do.
[0008]
[Means for Solving the Problems]
[0009]
The invention of claim 1, wherein in which the above-described problems is the joint structure for connecting a first pipe and a second pipe, a first pipe male thread is formed on the tip outer periphery, an outer diameter in the distal portion the outer surface A second pipe having an enlarged outer diameter stepped portion, and a coupling having a reduced inner diameter stepped portion having an inner diameter reduced and having an internal thread formed on the inner surface of the first tube. The reduced inner diameter step portion is located on the rear side of the second tube with respect to the outer diameter step portion, and is provided rotatably in the circumferential direction on the outer periphery of the end portion of the second tube. A female screw and a male screw of the first pipe are screwed together, and the second pipe is prevented from coming off from the coupling due to the presence of the outer diameter stepped portion of the second pipe. concave step portion is formed on an outer peripheral surface, like the male screw of the female screw of the coupling first tube is screwed In, locking ring between the rear end surface of the coupling and its step surface in said recessed step portion is a joint structure of a pipe, characterized in that it is fitted on.
[0010]
A second aspect of the present invention is the pipe joint structure according to the first aspect , wherein the locking ring can be fitted into and removed from the concave stepped portion.
[0011]
According to a third aspect of the present invention, the tip side portion of the first pipe from the male thread and the tip side portion of the second pipe from the reduced inner diameter step portion have a cross-sectional phase-joint shape, and the overlapping thereof. 2. The pipe joint structure according to claim 1, wherein the outer diameter of the first pipe is tapered and the inner diameter of the second pipe is enlarged.
[0012]
A fourth aspect of the present invention is the pipe joint structure according to the first aspect, wherein the inner surface of the first tube and the inner surface of the second tube are flush with each other.
[0013]
According to a fifth aspect of the invention, in Sai connected between the second pipe and the first pipe, the outer surface of the first pipe and the second pipe and the joint portion of the tube according to claim 1, wherein the flush It is a joint structure.
[0014]
The invention according to claim 6 is the joint structure for connecting the first pipe and the second pipe , the first pipe having a male screw formed on the outer periphery of the tip, and the outer diameter of which the outer diameter is enlarged on the outer surface of the tip. A second pipe having a stepped portion, and a coupling having a reduced inner diameter stepped portion with a reduced inner diameter and having an internal thread formed on the inner surface on the first tube side. A portion is located on the rear side of the second tube from the outer diameter stepped portion, and is provided to be rotatable in the circumferential direction on the outer periphery of the end portion of the second tube. A male screw of the pipe is screwed, and the second pipe is prevented from coming off from the coupling due to the presence of the reduced inner diameter step in the outer diameter step , and the first pipe except for the joint portion. and wherein the second pipe is curved tube, and the distal portion than the male thread of said first tube, said second tube The tip side portion from the inner diameter step portion has a cross-sectional phase-joint shape, and the overlapping surface thereof has a tapered outer diameter of the first tube, and an enlarged inner diameter of the second tube, A tapered engagement convex portion having an increased outer diameter is formed on a part of the overlapping surface of the first tube in the circumferential direction, and a part of the circumferential surface of the overlapping surface of the second tube is The pipe joint structure is characterized in that an engagement recess having a shape corresponding to the engagement protrusion is formed, and the engagement protrusion and the engagement recess are engaged with each other.
[0015]
[0016]
According to the seventh aspect of the present invention, an external thread is formed on the outer periphery of the distal end portion of the first tube, and an outer diameter step portion whose outer diameter is enlarged is formed on the outer surface of the distal end portion of the second tube. A coupling having a reduced inner diameter step portion with a reduced inner diameter and having an internal thread formed on the inner surface of the first tube side, and the reduced inner diameter step portion on the rear side of the second tube from the outer diameter step portion. And is provided so as to be rotatable in the circumferential direction on the outer periphery of the end portion of the second pipe, and the coupling is rotated so that the female screw and the male screw of the first pipe are screwed together. The two pipes are connected to the first pipe and the second pipe whose outer diameter stepped portion is prevented from coming off from the coupling due to the presence of the reduced inner diameter step portion, and the outer peripheral surface of the second pipe the concave step portion is formed, in a state where the male thread of said first pipe and a female screw of the coupling is screwed, in the recessed step There are a method of connecting pipes, characterized in that the to step surface and the locking ring between the rear end surface of the coupling fitted on.
[0017]
The invention according to claim 8 is the method of connecting pipes according to claim 7 , wherein the locking ring can be fitted and removed from the concave stepped portion.
[0018]
According to the ninth aspect of the present invention, a tip side portion of the first pipe from the male thread and a tip side portion of the second pipe having a reduced inner diameter step are formed in a cross-sectional phase-joint shape, and the overlapping thereof. The mating surface is formed such that the outer diameter of the first tube is tapered and the inner diameter of the second tube is enlarged, and the distal end portion of the first tube is inserted into the distal end portion of the second tube. The pipe connecting method according to claim 7 , wherein the male screw and the female screw are screwed together.
[0019]
The invention according to claim 10 forms a male screw on the outer periphery of the tip of the first tube, forms an outer diameter stepped portion whose outer diameter increases on the outer surface of the tip of the second tube, A coupling having a reduced inner diameter step portion with a reduced inner diameter and having an internal thread formed on the inner surface of the first tube side, and the reduced inner diameter step portion on the rear side of the second tube from the outer diameter step portion. And is provided so as to be rotatable in the circumferential direction on the outer periphery of the end portion of the second pipe, and the coupling is rotated so that the female screw and the male screw of the first pipe are screwed together, and the second The pipe is connected to the first pipe and the second pipe whose outer diameter step portion is prevented from coming off from the coupling due to the presence of the reduced inner diameter step portion, except for the joint portion. 1 tube and a curved tube of the second tube, and the distal portion than the male thread of said first tube, reduced inner diameter of the second tube The tip side part from the part is formed in a cross-sectional phase-joint shape, and the overlapping surface is formed so that the outer diameter of the first pipe is tapered and the inner diameter of the second pipe is enlarged. Then, a tapered engagement convex portion having an increased outer diameter is formed on a part of the overlapping surface of the first tube in the circumferential direction, and a part of the overlapping surface of the overlapping surface of the second tube in the circumferential direction in the engagement forms the engaging recess having a shape corresponding to the convex portions, after engaging with said engagement projection and the engagement recess, and characterized in that screwing said male thread and female thread It is the connection method of the pipe to do.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
A steel pipe connection joint according to the present invention will be described with reference to the drawings.
A connection joint structure according to the present invention is shown in FIGS. A first tube 10 having a male thread 11 formed on the outer periphery of the distal end portion, a second tube 20 having an outer diameter step portion 21 whose outer diameter expands on the outer surface of the tip portion, and a reduced inner diameter step portion 31 whose inner diameter decreases. And a coupling 30 having an internal thread 32 formed on the inner surface of the first tube side.
[0021]
The coupling 30 has a reduced inner diameter step portion 31 positioned on the rear side of the second tube 20 with respect to the outer diameter step portion 21 and is rotatable in the circumferential direction on the outer periphery of the end portion of the second tube 20. It is provided, and is prevented from coming off from the second pipe 20 by the presence of the expanded outer diameter step portion 21 and the reduced inner diameter step portion 31. The reduced inner diameter step portion 31 and the outer diameter step portion 21 may be tapered as shown in the drawing so that the inclined surfaces are in contact with each other.
[0022]
The female screw 32 of the coupling 30 is configured to be screwed with the male screw 11 of the first tube 10, and joins the distal end portion 12 of the first tube 10 and the distal end portion 22 of the second tube 20. In this state, the pipes are connected to each other by rotating the coupling 30. The concave step portion 23 formed on the outer peripheral surface of the second pipe 20 is rotated within the concave step portion 23 after the coupling 30 is rotated and the male screw 11 and the female screw 32 are screwed together. A locking ring 40 is fitted between the step surface and the rear end surface of the coupling. The locking ring 40 is sized so that the screw can only be engaged when the screw is completely screwed. When the locking ring 40 is mounted, the coupling screw 30 is reversely rotated to loosen the screw. There is no. Further, the locking ring 40 is detachable.
[0023]
On the other hand, the distal end portion 12 from the male thread 11 of the first tube 10 and the distal end portion 22 from the outer diameter stepped portion 21 of the second tube 20 have a cross-sectional phase-joint shape. It is comprised so that it may join firmly, and the rigidity of a junction part is improved. Further, the outer surface of the first tube 10 is tapered, the inner diameter of the second tube 20 is enlarged, and the distal end portion 12 of the first tube 10 is placed in the second tube 20. Easy to insert. Conversely, the inner diameter of the first tube may be enlarged first, the outer diameter of the second tube may be tapered, and the tip of the second tube may be easily inserted into the first tube.
[0024]
Moreover, as FIG. 1 shows, the joint structure is comprised so that the outer surface and inner surface of the 1st pipe | tube 10 and the 2nd pipe | tube 20 may become the same in a connection state.
[0025]
The joint structure according to the present invention may have any tube shape except for the joint portion. For example, a straight tube or a bent tube as illustrated may be used. When using a bent pipe, as shown in the figure, in advance, a tapered engagement convex portion 33 whose outer shape is increased is formed in a part of the circumferential direction of the overlapping surface of the first pipe 10, An engagement concave portion 24 having a shape corresponding to the engagement convex portion 33 is formed in a part of the overlapping surface of the second tube 20 in the circumferential direction, and the engagement convex portion 33 and the engagement concave portion 24 are engaged with each other. By configuring as described above, the joining position of the bent pipe to be connected can be easily determined.
[0026]
The connection joint according to the present invention can be formed as follows.
As shown in FIG. 3, a male screw tube 10A having a male screw 11 on the outer periphery, a tapered tube 20A having an outer diameter stepped portion 21 whose outer diameter expands on the outer surface of the tip, and a reduced inner diameter step whose inner diameter is reduced. A coupling 30 having a portion 31 and having an internal thread 32 formed on the inner surface on the first tube 10 side is formed in advance. The first pipe 10 is formed by welding the male screw pipe 10A and the bent pipe A, and the second pipe is formed by welding the tapered pipe 20A and the bent pipe B with the coupling 30 inserted into the tapered pipe 20A. 20 is formed, and the coupling 30 is formed so as not to come off from the tip of the second tube 20. Further, if the bent pipes A and B, the tapered pipe 20A, and the male screw pipe 10A are formed so as to be flush with each other, a joint portion having no irregularities on the inner face is formed. Further, if the outer shapes of the bent pipes A and B, the locking ring 40 and the coupling 30 are made the same diameter, the connecting portions and the outer surfaces of the bent pipes A and B are flush with each other after the pipes are connected. . After welding, each welded portion W is polished finely so that there is no step. These welding operations do not need to be performed at the construction site, and can be performed in advance in a place where the work is easy, such as a factory.
[0027]
Subsequently, a pipe connection method using the connection joint will be described with reference to FIGS. The tip ends of the first tube 10 and the second tube 20 are joined at the connection position. Next, in this joined state, the coupling 30 is rotated and the male screw portion 11 and the female screw portion 32 are screwed together. Since the coupling 30 and the second pipe 20 are configured so as not to come out of the coupling as described above, the first pipe 10 and the second pipe inevitably only by connecting the coupling 30 and the first pipe 10. 20 is connected. In order to rotate the coupling 30, as shown in FIG. 5, a convex portion 51 that engages with a concave portion 33 provided on the outer periphery of the coupling 30 and the outer periphery of the coupling 30 from the convex portion 51. It is possible to use a wrench 50 having a sickle-like support portion 52 extending in this manner and an operation portion 53 extending from the support portion 52 in the outer edge direction. If the operation part 53 is pulled in the circumferential direction after the convex part 51 and the concave part 33 are engaged, the coupling 30 can be easily rotated. After the female screw 32 and the male screw 11 are screwed together by rotating the coupling 30 to a position where it does not move, the step surface and the coupling are formed in the concave step portion 23 formed on the outer peripheral surface of the second pipe 20. A loosening prevention ring 40 is fitted between the rear end face 30. The attachment of the locking ring 40 prevents the coupling 30 from rotating in either forward or reverse direction, so that it does not loosen after connection. When this locking ring 40 is attached, the mode shown in FIG. 6 is obtained, and the connection between the first pipe 10 and the second pipe 20 is completed.
[0028]
【The invention's effect】
The connecting joint structure for pipes according to the present invention can easily connect pipes in a short time, can be formed into a shape in which the joint part cannot be uneven, and is excellent in workability in a narrow part. Further, since the joint portion can be formed in the factory in advance, a highly accurate joint structure can be obtained.
[Brief description of the drawings]
FIG. 1 is a sectional view of a joint structure. FIG. 2 is a top view of the joint structure.
FIG. 3 is an exploded perspective view of a joint structure.
FIG. 4 is a perspective view of a joint structure.
FIG. 5 is a view showing a wrench that rotates a coupling.
FIG. 6 is a state diagram showing a state after the pipes are connected.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... 1st pipe | tube, 10A ... Male threaded pipe, 11 ... Male thread, 20 ... 2nd pipe | tube, 21 ... Expanded outer diameter step part, 23 ... Concave step part, 30 ... Coupling, 31 ... Reduced inner diameter step part, 33 ... concave part, 40 ... locking ring, 50 ... wrench, W ... weld.

Claims

In the joint structure connecting the first pipe and the second pipe,
A first tube having a male thread formed on the outer periphery of the tip, a second tube having an outer diameter stepped portion whose outer diameter expands on the outer surface of the tip portion, a reduced inner diameter step portion whose inner diameter is reduced, and A coupling having a female thread formed on the inner surface of the first tube side,
The coupling has a reduced inner diameter step portion located on the rear side of the second tube from the outer diameter step portion, and is provided rotatably in the circumferential direction on the outer periphery of the end portion of the second tube.
Due to the rotation of the coupling, the female thread and the male thread of the first pipe are screwed together, and the second pipe is prevented from coming off from the coupling due to the presence of the outer diameter stepped portion. And
Recessed step is formed on an outer peripheral surface of the second tube, in a state where the male thread of said first pipe and a female screw of the coupling are screwed together, in said recessed step portion and its step surface of the coupling A pipe joint structure , wherein a locking ring is fitted between the rear end face and the pipe.

The locking ring joint structure according to claim 1, wherein the tube is capable to be fitted and desorption with respect to the said recessed step.

A tip side portion of the first tube from the male screw and a tip side portion of the second pipe having a reduced inner diameter step have a cross-sectional phase-joint shape, and an overlapping surface of the first tube The pipe joint structure according to claim 1, wherein an outer diameter is tapered and an inner diameter of the second pipe is enlarged.

The pipe joint structure according to claim 1, wherein an inner surface of the first tube and an inner surface of the second tube are flush with each other.

Wherein the first tube and again connected with said second pipe, joint structure of the tube according to claim 1, wherein an outer surface of the second pipe and the joint portion between the first pipe is flush.

In the joint structure connecting the first pipe and the second pipe,
A first tube having a male thread formed on the outer periphery of the tip, a second tube having an outer diameter stepped portion whose outer diameter expands on the outer surface of the tip portion, a reduced inner diameter step portion whose inner diameter is reduced, and A coupling having a female thread formed on the inner surface of the first tube side,
The coupling has a reduced inner diameter step portion located on the rear side of the second tube from the outer diameter step portion, and is provided rotatably in the circumferential direction on the outer periphery of the end portion of the second tube.
Due to the rotation of the coupling, the female thread and the male thread of the first pipe are screwed together, and the second pipe is prevented from coming off from the coupling due to the presence of the outer diameter stepped portion. And
Except for the joint portion, the first pipe and the second pipe are bent pipes,
A tip side portion of the first tube from the male screw and a tip side portion of the second pipe having a reduced inner diameter step have a cross-sectional phase-joint shape, and an overlapping surface of the first tube The outer diameter is tapered, the inner diameter of the second tube is enlarged,
A tapered engagement convex part with an increased outer diameter is formed on a part of the circumferential direction of the overlapping surface of the first tube, and a part of the circumferential direction of the overlapping surface of the second tube is A pipe joint structure, wherein an engagement concave portion having a shape corresponding to the engagement convex portion is formed, and the engagement convex portion and the engagement concave portion are engaged with each other.

Forming an external thread on the outer periphery of the distal end of the first tube, forming an outer diameter stepped portion whose outer diameter expands on the outer surface of the distal end of the second tube;
The second pipe includes a coupling having a reduced inner diameter step portion whose inner diameter is reduced and an internal thread is formed on the inner surface of the first tube side. Two pipes are located on the rear side, and provided so as to be rotatable in the circumferential direction on the outer periphery of the end of the second pipe,
The coupling is rotated so that the female screw and the male screw of the first pipe are screwed together, and the second pipe has a larger outer diameter stepped portion that is removed from the coupling due to the presence of the reduced inner diameter stepped portion. The first pipe and the second pipe being stopped are connected,
Recessed step is formed on an outer peripheral surface of the second tube, in a state where the male thread of said first pipe and a female screw of the coupling are screwed together, in said recessed step portion and its step surface of the coupling A pipe connecting method, wherein a locking ring is fitted between the rear end face and the pipe.

The pipe connecting method according to claim 7 , wherein the locking ring can be fitted and removed from the recessed step portion.

A portion on the tip side from the male thread of the first tube and a portion on the tip side from the reduced inner diameter step portion of the second tube are formed in a cross-sectional phase-joint shape, and an overlapping surface thereof is formed on the first tube. The outer diameter of the second tube is enlarged and the inner diameter of the second tube is enlarged, the distal end portion of the first tube is inserted into the distal end portion of the second tube and joined, and the male screw and female The pipe connecting method according to claim 7, wherein the screw is screwed together.

Forming an external thread on the outer periphery of the distal end of the first tube, forming an outer diameter stepped portion whose outer diameter expands on the outer surface of the distal end of the second tube;
The second pipe includes a coupling having a reduced inner diameter step portion whose inner diameter is reduced and an internal thread is formed on the inner surface of the first tube side. Two pipes are located on the rear side, and provided so as to be rotatable in the circumferential direction on the outer periphery of the end of the second pipe,
The coupling is rotated so that the female screw and the male screw of the first pipe are screwed together, and the second pipe has an outer diameter step portion that is prevented from coming off from the coupling due to the presence of the reduced inner diameter step portion. The first pipe and the second pipe are connected,
Except for the joint portion, the first pipe and the second pipe are bent pipes,
A portion on the tip side from the male thread of the first tube and a portion on the tip side from the reduced inner diameter step portion of the second tube are formed in a cross-sectional phase-joint shape, and an overlapping surface thereof is formed on the first tube. The outer diameter of the second tube is tapered, and the inner diameter of the second tube is expanded.
In a part of the circumferential direction of the overlapping surface of the first pipe, a tapered engagement convex portion having an increased outer diameter is formed, and in a part of the circumferential direction of the overlapping surface of the second pipe, A tube characterized in that an engagement recess having a shape corresponding to the engagement protrusion is formed, and the male screw and the female screw are screwed together after the engagement protrusion and the engagement recess are engaged. Connection method.