JP4571257B2

JP4571257B2 - Connection structure of steel water pipe and mechanical joint

Info

Publication number: JP4571257B2
Application number: JP34177499A
Authority: JP
Inventors: 徹岩原; 啓司重野; 佳典中田
Original assignee: 株式会社日邦バルブ
Priority date: 1999-12-01
Filing date: 1999-12-01
Publication date: 2010-10-27
Anticipated expiration: 2019-12-01
Also published as: JP2001159482A

Description

【０００１】
【産業上の利用分野】
本発明は、水道用管とメカニカル継手の接続構造に関し、さらに詳細に言えば、管端コアを備えた鋼製の水道用管とメカニカル継手の接続構造に関する。
【０００２】
【従来の技術】
水道の配管に使用する管として鋼製のものがある。この管は適宜長さに切断して使用されるが、埋設して使用する間にその切断した端部において錆が発生する。その錆が配管内に侵入しないようにするために、管端コアをその端部に取り付け、メカニカル継手を用いて他の管或いは機器に接続する。従来の管端コアを備えた管及びメカニカル継手の一例を図２に示す。
【０００３】
図において符号１は接続される管であり、この管１は例えば鋼製である。その接続される端部１ａには、管端コア２がその一端側の挿入部２ａにおいて圧入されて取り付けられている。この管端コア２の先端部２ｂは、圧入部２ａとの境界に形成される肩部２ｃが配管の端面に当接した状態で配管１の外側に位置している。そしてその外周部には円周溝２ｄが形成され、この溝２ｄに後述の継手本体との間をシールするパッキン或いはコアパッキン３が収受されている。このパッキン３は、通常継手への挿入を行いやすくするために、断面Ｕ字型（Ｕパッキン）或いはＶ字型（Ｖパッキン）となっている。図示の通り、管端コア２の外径は管１の外径に略等しく、コアパッキン３の自由状態（管端コア２の溝２ｄに取り付けた状態）での外径は管１の外径より大きくなっている。
【０００４】
符号４はメカニカル継手であり、その継手本体５は、小径部５ａと、小径部５ａより内径の大きい中間部５ｂと、中間部５ｂより内径が大きい大径部５ｄと傾斜部５ｅとからなるパッキン収納部５ｃとを備えている。傾斜部５ｅは、大径部５ｄから中間部５ｂに繋がる部分であり、中間部５ｂに向かって漸次縮径するように傾斜した内周面を有している。符号６は、配管１の外周上に配置され、パッキン収納部５ｃに収受されるパッキンであり、圧縮されて管１と継手本体５の間をシールする。符号７はワッシャであり、符号８はロックリングである。このロックリング８はその内周に突起或いは爪８ａを備え、さらに円周方向のある箇所において割られており、外力を加えることにより縮径するようになっている。なお、ロックリング８の外周８ｂ側は傾斜しており、ワッシャ７から遠ざかるに従いその外形が小さくなっている。符号９は袋ナットであり、本体５のパッキン収納部５ｃの大径部５ｄの外周に形成された雄ねじと螺合する雌ねじが形成されている。さらにその後端部の内周側は、ロックリング８の外周８ｂに対応した径斜面となっている。
【０００５】
上記の構成になる継手では、管端コア２を管１に圧入して取り付け、溝２ｄにコアパッキン３を装着した状態で本体５の中間部に挿入する。そして、袋ナット９を本体５に螺合させて締めつけると、袋ナットの前進（図２において右方向へ進む）に従い、ロックリング８とワッシャ７が前進してパッキン６をパッキン収納部５ｃ内で圧縮する。その際、ロックリング８は次第に縮径し、遂には管１の外周に食いつく。さらにパッキン６を圧縮するために袋ナット９を回すと、管１も同時に前進し、管端コア２の先端面が本体５の小径部５ａと中間部５ｂの間の肩部５ｆに当接する。この状態で管１と本体５との間がコアパッキン３及びパッキン６によりシールされる。そして、ロックリング８が管１に食いついているので、その抜け止めが行われる。
【０００６】
ところで、上記の構成からなる管及び継手においては、管端コア２の先端部２ｂの外径が管１の外径に略等しくなっており、溝２ｄに取り付けられたコアパッキン３の外径は、十分な圧縮代を取るために管１の外径より大分大きくなっている。従って、継手本体５に対して事前にパッキン６、ワッシャ７、ロックリング８を装着し、袋ナット９を本体５に螺合させて仮止めした状態で、コアパッキン３が取り付けられた管端コア２を管１の先端に取り付けて挿入しようとすると、コアパッキン３がロックリング８、ワッシャ７、パッキン６に当たって挿入出来ない。また、パッキン６を変形させて挿入できたとしてもコアパッキン３がロックリング８の内周側の突起８ａにより傷つけられ、そのシールの性能を低下させてしまう。
【０００７】
そこで、従来この種の継手を用いて管１を接続する場合、先ず管１に袋ナット９、ロックリング８、ワッシャ７、パッキン６を装着し、その後先端に管端コア２を取り付け、コアパッキンを装着した後、この管１を本体５内に挿入して、ナット９を回して締めつける作業を行っていた。この作業は配管の現場で行うこととなるので、それぞれの部品を個別に管理しておく必要があり、また、その現場での接続作業に長時間を要する。
【０００８】
また、ロックリング８が管１に食いついた後も、パッキン６を十分圧縮して良好なシールを得るためには袋ナット９の更なる締めつけが必要であり、その際管１も継手本体５に対して前進するので、事前に管端コア２の端部２ｂと本体５の肩部５ｆとの間に一定のクリアランスを確保する必要がある。その為に、管１を本体に挿入する際に、一旦管端コア２が本体５の肩部５ｆに当接する位置まで挿入し、その後、一定の長さ分だけ後ろ方向に戻すようにしており、作業が煩雑である。
【０００９】
さらには、ロックリング８が管１に食いついた後に袋ナット９を回転させると管１も回転してしまい（供回り）、接続作業の完了している管１の反対側が緩んでしまう。それを防止するために、他の工具で管１を掴み、管１の回転を防止しながら袋ナットの締めつけ作業を行う必要がある。
【００１０】
【発明が解決しようとする課題】
本願発明は、上記従来の管端コア付き管の接続に関する問題点に鑑みなされたものであり、管の接続作業の効率化を図れるようにした鋼製の管とメカニカル継手との接続構造を提供することをその課題とする。
【００１１】
具体的には、事前に継手本体にパッキン、ワッシャ、ロックリングを装着し、袋ナットを継手本体に仮止めし、これらを継手ユニットとして提供し、管端コア及びコアパッキンを取り付けた管をそのまま継手ユニットに挿通できるようにする。
【００１２】
また、ロックリングが配管に食いついた後に袋ナットを回転させた場合に、配管の供回りを防止できるようにする。
【００１３】
さらに、管端コア及びコアパッキンを損傷すること無く、管をメカニカル継手に挿入できるようにする。
【００１４】
さらに、ロックリングが配管に食いついた後の配管の前進を許容する為のクリアランスを事前に確保し、管の引き戻し作業が不要となるようにする。
【００１５】
【課題を解決するための手段】
上記課題を解決するために、本願発明の鋼製の水道用管とメカニカル継手の接続構造においては、管の一端に管端コアを取付ける。その管端コアは、管の一端内に挿入される挿入部と、管の外部に位置し、その外周上に形成された円周溝を備え、外径が管の少なくとも一端から所定の長さ部分における外径より小さいパッキン受け部とを備えている。そしてその円周溝には封止用のコアパッキンが収受される。
一方メカニカル継手は、一端側から管の前記一端側を受け入れる中空の継手本体と、管を囲繞して管の一端側から順に位置するパッキンとロックリングと袋ナットとを備え、袋ナットを継手本体に螺合して締付けることによりロックリングを縮径するとともに継手本体側へ移動させて、パッキンを継手本体内で圧縮して管の外周に密着させてシールするとともに、ロックリングを管の外周に食付かせて管とメカニカル継手とを結合する構成とする。
そして、その継手本体は、一端側から、パッキンを収受するパッキン収納部と、パッキン収納部より内径が小さく、管の一端側先端部を受け入れる管受入部と、管受入部より内径が小さく、その内周にコアパッキンが液密に摺接するパッキン摺接部とを備えており、円周溝に収受されて自由状態におけるコアパッキンの外径は、パッキンとロックリングの自由状態での内径及び袋ナットの内径より小さくなっている。
コアパッキンの自由状態での外径は、管の前記所定の長さ部分の外径と同じ若しくは僅かに大きく形成することができる。さらに、コアパッキンの自由状態での外径は、管の所定の長さ部分の外径より０．２ｍｍ以上大きくならないようにするとよい。
継手本体は、パッキン摺接部に関して管受け入れ部と反対側に形成された、パッキン摺接部より内径の小さい小径部を備え、管端コアはさらに、パッキン受け部から管端コアの軸心方向に伸張し、その先端が小径部の径方向に広がる側面に当接可能で、変形可能な傾斜部を備えるようにすることができる。そして、管を継手本体に挿入する際に、その傾斜部の先端が小径部の側面に当接し、管の継手本体に対する位置決めを行うことができる。
その管端コアの傾斜部は、端部に向かうにつれて径が大きくなる末広がり状に形成することができ、さらに、傾斜部は円周方向で複数個に分割してもよい。
ロックリングと袋ナットとの間に配置され、袋ナットを締め付ける際に袋ナットからの力をロックリングに作用させる押圧部材と、袋ナットと押圧部材との互いに力を作用させる面の間に配置された、摩擦係数の小さい材料で作られた薄いシート部材とをさらに設けても良い。
【００１８】
【発明の実施の形態】
以下、図面に基づき本願発明の具体的実施の形態を説明するが、本願発明の範囲は以下に説明される実施の形態に限定されるものではない。
【００１９】
図１は、本発明にかかる配管用の管端コア付き管１１をメカニカル継手３１に挿入した状態を示す断面図であり、未だ袋ナット７１は締めつけてない状態である。図において符号１１は配管用の管である。管１１は鋼製である。その接続される側である接続端部１３には、管端コア１７が取り付けられている。
【００２０】
管端コア１７は本実施の形態では樹脂製であり、材料として例えばポリエチレン等を使用することが出来る。管端コア１７は中空の部材であり、管１１の接続端部１３内へ圧入される、円筒状の取り付け部１９を備えている。図示してないが、この取り付け部１９の外周には、円周方向に延びて形成されたリブ或いは襞が形成され、管１１に圧入した際にそれが潰れて、管１１と管端コア１７との間を封止するようにすることができる。
【００２１】
管端コア１７は、取り付け部１９に同軸状に繋がり、取り付け部１９より外径の大きい、円筒状のコアパッキン取り付け部２１と、さらにこのコアパッキン取り付け部２１から取り付け部１９とは反対側に同軸状に延びる、コアパッキン取り付け部２１より外径の小さい、円筒状の延長部２３とを備えている。そして、コアパッキン取り付け部２１の外周には、円周方向に延びて形成された溝２５が形成されている。この溝２５には、従来使用していたＵパッキン或いはＶパッキンと同じタイプで差し支えのないコアパッキン２９が収受され、装着されている。なお、延長部２３の根元部分即ちコアパッキン取り付け部２１につながる部分から、管端コア１７の軸芯に対して傾斜しながら延びている傾斜部２７が形成されている。本実施の形態ではこの傾斜部２７は、コアパッキン取り付け部２１から遠ざかるにつれて径が大きくなる一体型の末広がり部となっているが、円周方向で複数に分割されたタイプでもよい。この傾斜部２７については後述する。管端コア１７は、コアパッキン取り付け部２１の片側の端面２２が管１１の端面１５に当接した状態で取り付けられている。図示のとおり、管端コア１７のコアパッキン取り付け部２１の外径は管１１の外径より小さい。また、管端コア１７に取り付けられたコアパッキン２９の外径は、自由状態すなわち圧縮されていない状態では圧縮代を確保するに十分なだけコアパッキン取り付け部２１の外径より大きい。しかし、後述のロックリング５７等の内径よりは小さく、本実施の形態ではその外径は管１１の外径と等しい、若しくは大きくても０．２ｍｍ程度上回る程度に止めてある。
【００２２】
符号３１はメカニカル継手であり、３３はその継手本体である。継手本体３３は管１１の挿入口となるパッキン収納部３５を備え、そのパッキン収納部３５は端部側となる真直部３７とそれに連なる傾斜部３９とからなっている。真直部３８は略円筒状となっており、同一内径の内周面３８を備え、傾斜部３９は、真直部３７から離れるに連れて内径が小さくなる内周面４０を備えている。真直部３７の外周には、後述の袋ナット７１が螺合する雄ねじ４１が形成されている。
【００２３】
符号４３は、パッキン収納部３５に続いて形成された管端収納部であり、図示のように、管１１の端部１３を収納する部分であり、略円筒状をなし、その内径は管１１の外径より若干大きくなっている。符号４５は、管端収納部４３より内径が小さくなった、略円筒状のパッキン摺接部であり、その内径は管端コア１７のコアパッキン取り付け部２１の外径と同じ若しくは若干大きく、コアパッキン２９は十分に径方向で圧縮される寸法となっている。継手本体３３にはさらに、パッキン摺接部４５に続いてそれより内径の小さい、略円筒状の小径部４７が形成されている。そして管１１がこの管継手本体３３内へ所定の長さだけ挿入されると、この小径部４７のパッキン摺接部４５側の端面４８に、管端コア１７の傾斜部２７の先端部２８が当接するようになっている。
【００２４】
符号４９は管１の周囲を囲み、継手本体３３のパッキン収納部３５内に収受される円環状のパッキンであり、その外周面５１がパッキン収納部３５の内周面３８と４０に当接している。自由状態での内径は管１１の外径より大きく、図示した、後述の袋ナットがまだ締めつけられていない状態では、内周面５３と管１１の外周面との間には僅かな隙間がある。
【００２５】
パッキン４９の外側に、両側面が略並行である板状のパッキン押圧部材５５が配置されている。パッキン押圧部材５５は円環状をしており、その内径は管１１の外径より若干大きく、外径はパッキン収納部３５の真直部３７の内径に対応した寸法となっており、真直部３７に沿って継手本体３３の軸方向に移動可能となっている。
【００２６】
パッキン押圧部材５５を挟んでパッキン４９と反対側にロックリング５７が配置されている。ロックリング５７は円環状の部材を円周方向のある位置で割って形成しており、自由な状態ではその位置で両端部間に隙間があり、外力を加えるとその隙間を詰めながら径が縮小するようになっている。この構成は公知であるので詳細な説明は省略する。ロックリング５７の内周側には爪５９が形成されている。また、外周面６１はパッキン押圧部材５５から離れるにつれて外径が小さくなるように斜面に形成されている。図示の状態でのロックリング５７の内径は管１１の外径より大きい。
【００２７】
符号６３は、円環状のロックリング押圧部材であり、その内周面６５はロックリング５７の外周面６１に対応した形状の斜面になっており、この部分でロックリング５７に当接している。ロックリング押圧部材６３の内径は、管１１の外径より大きい。
【００２８】
符号７１は袋ナットであり、その雌ねじ７３が継手本体３３の雄ねじ４１に螺合することにより、継手本体３３に取り付けられる。図示のとおり袋ナット７１はその内部にロックリング５７、ロックリング押圧部材６３等を収受するようになっており、その頂壁７５には管１１が挿入される孔７７が形成されている。そして頂壁７５の内側面７９が、ロックリング押圧部材６３の外側面６７に対向している。内側面７９と外側面６７との間に、円環状の薄いシート部材８１が配置されている。このシート部材８１は、摩擦係数の比較的小さい材料、例えばテフロン等の樹脂で作られている。
【００２９】
上記の管１１をメカニカル継手３１に接続する手順について説明すると、メカニカル継手本体に対してパッキン４９、パッキン押圧部材５５、ロックリング５７、ロックリング押圧部材、６３シート部材８１及び袋ナット７１を、図示の状態に予め組付け、ユニット化しておく。この状態では袋ナット７１は本体３３に外れない程度に螺合させておくだけでよく、ネジを締めつけてパッキン４９を圧縮する必要はない。このユニット化したメカニカル継手３１に、管端コア１７を取りつけ、コアパッキン２９を装着した管１１を挿入する。その際、前述の如く管端コア１７のパッキン取り付け部２１の外径は管１１の外径より小さく、コアパッキン２９の外径も管１１の外径と等しいか、ほんの僅かに大きい程度でロックリング５７等の内径より小さく、一方管１１の外径もロックリング５７等の内径より小さいので、ロックリング５７等が管１１の挿入の妨げとなることはなく、またコアパッキン２９が傷つけられることもない。管１１は、管端コア１７の傾斜部２７の先端部２８が継手本体３３の小径部４７の内側面４８に当接するまで挿入する。
【００３０】
次に袋ナット７１を締める。袋ナット７１を継手本体３３に対して締めつけるに従い、押圧力がシート部材８１、ロックリング押圧部材６３、ロックリング５７、パッキン押圧部材５５、パッキン４９に加わり、パッキン４９が圧縮されて管１１の外周面上に圧着させられ、この部分をシールする。ロックリング５７は軸方向に移動するとともに、その径が縮小し、管１１に食い付き、管１１の抜け止めを行う。さらに袋ナット７１を締めつけると、管端コア１７の傾斜部２７が変形することにより、管１１も一緒に継手本体３３に対して移動し、パッキン４９をさらに圧縮する。その際、シート部材８１の摩擦係数が小さいので、袋ナット７１が回転しても、袋ナット７１とシート部材８１との間或いはシート部材８１とロックリング押圧部材６３との間で滑りが生じ、ロックリング５７、管１１が袋ナット７１と共に回転するのが防止される。
【００３１】
【発明の効果】
以上詳述したとおり、本発明によれば、メカニカル継手を予め仮組み立てを行っておき、それに管端コアを取り付けコアパッキンを装着した管を挿入できるので、管の接続作業の効率が大幅に向上する。この場合、メカニカル継手を仮組み立てしてユニット化して管理できるので、従来の個々の部品で管理する場合に比してきわめて好都合である。また、従前行っていた、一旦挿入した管を所定の長さ分だけ引き戻す作業も不要となる。また、袋ナットを締めつける際の管の供回りも防止される。
【図面の簡単な説明】
【図１】本発明の実施の形態に係る管及びメカニカル継手の取り付け状態を示す断面図である。
【図２】従来例の管及びメカニカル継手を示す断面図である。
【符号の説明】
１１配管用の管
１７管端コア
２１パッキン取り付け部
２５溝
２９コアパッキン
２７傾斜延長部
３１メカニカル継手
３３継手本体
３５パッキン収納部
４３管端収納部
４５パッキン摺接部
４９パッキン
５５パッキン押圧部材
５７ロックリング
６３ロックリング押圧部材
７１袋ナット
８１シート部材[0001]
[Industrial application fields]
The present invention relates to a connection structure between a water pipe and a mechanical joint, and more particularly, to a connection structure between a steel water pipe having a pipe end core and a mechanical joint.
[0002]
[Prior art]
Steel pipes are used for water supply piping. This tube is used by cutting it to a suitable length, but rust is generated at the cut ends while being buried and used. In order to prevent the rust from entering the pipe, a pipe end core is attached to the end and connected to another pipe or equipment using a mechanical joint. An example of a pipe and a mechanical joint provided with a conventional pipe end core is shown in FIG.
[0003]
In the figure, reference numeral 1 denotes a pipe to be connected, and this pipe 1 is made of, for example, steel. A pipe end core 2 is press-fitted and attached to the end portion 1a to be connected at the insertion portion 2a on one end side. The distal end portion 2b of the tube end core 2 is located outside the pipe 1 with a shoulder portion 2c formed at the boundary with the press-fit portion 2a in contact with the end surface of the pipe. A circumferential groove 2d is formed in the outer peripheral portion, and a packing or core packing 3 for sealing between the joint body described later is received in the groove 2d. This packing 3 is usually U-shaped in section (U packing) or V-shaped (V packing) in order to facilitate insertion into a joint. As illustrated, the outer diameter of the tube end core 2 is substantially equal to the outer diameter of the tube 1, and the outer diameter of the core packing 3 in the free state (attached to the groove 2 d of the tube end core 2) is the outer diameter of the tube 1. It is getting bigger.
[0004]
Reference numeral 4 denotes a mechanical joint. The joint body 5 includes a small diameter part 5a, an intermediate part 5b having an inner diameter larger than the small diameter part 5a, a large diameter part 5d having an inner diameter larger than the intermediate part 5b, and an inclined part 5e. And a storage portion 5c. The inclined portion 5e is a portion that is connected from the large diameter portion 5d to the intermediate portion 5b, and has an inner peripheral surface that is inclined so as to be gradually reduced in diameter toward the intermediate portion 5b. Reference numeral 6 denotes a packing which is disposed on the outer periphery of the pipe 1 and received by the packing storage portion 5 c, and is compressed to seal between the pipe 1 and the joint body 5. Reference numeral 7 is a washer, and reference numeral 8 is a lock ring. The lock ring 8 is provided with a projection or claw 8a on its inner periphery, and is further broken at a certain position in the circumferential direction so as to be reduced in diameter by applying an external force. In addition, the outer periphery 8b side of the lock ring 8 is inclined, and its outer shape becomes smaller as the distance from the washer 7 increases. Reference numeral 9 denotes a cap nut, in which a female screw that is screwed with a male screw formed on the outer periphery of the large-diameter portion 5d of the packing storage portion 5c of the main body 5 is formed. Furthermore, the inner peripheral side of the rear end portion is a slope having a diameter corresponding to the outer periphery 8 b of the lock ring 8.
[0005]
In the joint having the above-described configuration, the pipe end core 2 is press-fitted and attached to the pipe 1 and is inserted into the intermediate portion of the main body 5 with the core packing 3 attached to the groove 2d. Then, when the cap nut 9 is screwed into the main body 5 and tightened, the lock ring 8 and the washer 7 move forward in accordance with the advance of the cap nut (goes to the right in FIG. 2), and the packing 6 is moved into the packing storage portion 5c. Compress. At this time, the diameter of the lock ring 8 gradually decreases, and finally bites on the outer periphery of the tube 1. When the cap nut 9 is further rotated to compress the packing 6, the tube 1 is also advanced simultaneously, and the tip end surface of the tube end core 2 comes into contact with the shoulder portion 5f between the small diameter portion 5a and the intermediate portion 5b of the main body 5. In this state, the space between the tube 1 and the main body 5 is sealed by the core packing 3 and the packing 6. And since the lock ring 8 bites into the pipe | tube 1, the removal prevention is performed.
[0006]
By the way, in the pipe and joint having the above-described configuration, the outer diameter of the distal end portion 2b of the pipe end core 2 is substantially equal to the outer diameter of the pipe 1, and the outer diameter of the core packing 3 attached to the groove 2d is In order to obtain a sufficient compression allowance, it is much larger than the outer diameter of the tube 1. Therefore, the pipe end core to which the core packing 3 is attached in a state where the packing 6, the washer 7, and the lock ring 8 are attached to the joint body 5 in advance and the cap nut 9 is screwed into the body 5 and temporarily fixed. If 2 is attached to the tip of the tube 1 and is inserted, the core packing 3 hits the lock ring 8, washer 7 and packing 6 and cannot be inserted. Further, even if the packing 6 can be deformed and inserted, the core packing 3 is damaged by the protrusion 8a on the inner peripheral side of the lock ring 8, and the performance of the seal is deteriorated.
[0007]
Therefore, when connecting the pipe 1 using this type of joint, the cap nut 9, the lock ring 8, the washer 7, and the packing 6 are first attached to the pipe 1, and then the pipe end core 2 is attached to the tip. After mounting, the tube 1 was inserted into the main body 5 and the nut 9 was turned to tighten it. Since this work is performed at the site of piping, it is necessary to manage each part individually, and a long time is required for connection work at the site.
[0008]
Further, even after the lock ring 8 bites into the pipe 1, it is necessary to further tighten the cap nut 9 in order to sufficiently compress the packing 6 to obtain a good seal. Since it moves forward, it is necessary to secure a certain clearance between the end 2b of the tube end core 2 and the shoulder 5f of the main body 5 in advance. Therefore, when the tube 1 is inserted into the main body, the tube end core 2 is once inserted to a position where it abuts against the shoulder portion 5f of the main body 5, and then returned backward by a certain length. The work is complicated.
[0009]
Furthermore, when the cap nut 9 is rotated after the lock ring 8 bites into the pipe 1, the pipe 1 is also rotated (turned around), and the opposite side of the pipe 1 where the connection work has been completed is loosened. In order to prevent this, it is necessary to grip the tube 1 with another tool and tighten the cap nut while preventing the tube 1 from rotating.
[0010]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems related to the connection of the pipe with a core at the end, and provides a connection structure between a steel pipe and a mechanical joint that can improve the efficiency of the pipe connection work. The task is to do.
[0011]
Specifically, packing, washers, and lock rings are attached to the joint body in advance, and the cap nut is temporarily fixed to the joint body. These are provided as a joint unit, and the pipe with the pipe end core and core packing attached is left as it is. Make sure that the fitting unit can be inserted.
[0012]
Further, when the cap nut is rotated after the lock ring bites into the pipe, the circulation of the pipe can be prevented.
[0013]
Further, the pipe can be inserted into the mechanical joint without damaging the pipe end core and the core packing .
[0014]
Furthermore, a clearance for allowing the pipe to move forward after the lock ring bites into the pipe is secured in advance so that the pipe pull-back operation is not necessary.
[0015]
[Means for Solving the Problems]
In order to solve the above problems, in the connection structure of a steel water pipe and a mechanical joint according to the present invention, a pipe end core is attached to one end of the pipe. The tube end core includes an insertion portion to be inserted into one end of the tube, a circumferential groove formed on the outer periphery of the tube, and has an outer diameter of a predetermined length from at least one end of the tube. And a packing receiving portion smaller than the outer diameter of the portion. A sealing core packing is received in the circumferential groove.
On the other hand, the mechanical joint includes a hollow joint body that receives the one end side of the pipe from one end side, a packing, a lock ring, and a cap nut that are positioned in order from the one end side of the pipe around the pipe, The lock ring is reduced in diameter by being screwed onto and tightened, and moved to the joint body side, and the packing is compressed in the joint body to be in close contact with the outer periphery of the pipe, and the lock ring is attached to the outer circumference of the pipe. The pipe and the mechanical joint are joined together.
The joint body has a packing housing portion that receives the packing from one end side, an inner diameter smaller than that of the packing housing portion, a tube receiving portion that receives the tip end portion of the pipe, and an inner diameter smaller than that of the tube receiving portion. A packing sliding contact portion in which the core packing is in fluid-tight sliding contact with the inner periphery, and the outer diameter of the core packing received in the circumferential groove in the free state is the inner diameter and bag in the free state of the packing and the lock ring. It is smaller than the inner diameter of the nut.
The outer diameter of the core packing in the free state can be formed to be the same as or slightly larger than the outer diameter of the predetermined length portion of the pipe. Furthermore, it is preferable that the outer diameter of the core packing in the free state does not become larger than the outer diameter of the predetermined length portion of the pipe by 0.2 mm or more.
The joint body includes a small-diameter portion having an inner diameter smaller than that of the packing sliding contact portion, which is formed on the side opposite to the pipe receiving portion with respect to the packing sliding contact portion, and the pipe end core further extends in the axial direction of the pipe end core from the packing receiving portion. It is possible to provide an inclined portion that can be deformed and can be brought into contact with a side surface of the small-diameter portion that extends in the radial direction. And when inserting a pipe | tube into a coupling main body, the front-end | tip of the inclination part contact | abuts to the side surface of a small diameter part, and can position with respect to the coupling main body of a pipe | tube.
The inclined portion of the tube end core can be formed in a divergent shape with a diameter increasing toward the end, and the inclined portion may be divided into a plurality in the circumferential direction.
It is arranged between the lock ring and the cap nut, and is arranged between the pressing member that applies the force from the cap nut to the lock ring when tightening the cap nut, and the surface on which the force is applied between the cap nut and the pressing member. A thin sheet member made of a material having a small friction coefficient may be further provided.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the embodiments described below.
[0019]
FIG. 1 is a cross-sectional view showing a state where a pipe end cored tube 11 for piping according to the present invention is inserted into a mechanical joint 31, and a cap nut 71 is not yet tightened. In the figure, reference numeral 11 denotes a pipe for piping. The tube 11 is made of steel. A pipe end core 17 is attached to the connection end 13 which is the side to be connected.
[0020]
The tube end core 17 is made of resin in the present embodiment, and for example, polyethylene or the like can be used as a material. The tube end core 17 is a hollow member and includes a cylindrical attachment portion 19 that is press-fitted into the connection end portion 13 of the tube 11. Although not shown in the figure, a rib or ridge formed to extend in the circumferential direction is formed on the outer periphery of the attachment portion 19, and when it is press-fitted into the tube 11, it is crushed, and the tube 11 and the tube end core 17. Between the two can be sealed.
[0021]
The tube end core 17 is coaxially connected to the attachment portion 19 and has a cylindrical core packing attachment portion 21 having an outer diameter larger than that of the attachment portion 19, and further from the core packing attachment portion 21 to the opposite side of the attachment portion 19. A cylindrical extension 23 having an outer diameter smaller than that of the core packing attachment portion 21 is provided. And the groove | channel 25 extended in the circumferential direction and formed in the outer periphery of the core packing attachment part 21 is formed. In this groove 25, a core packing 29 of the same type as the U packing or V packing used conventionally is received and attached. An inclined portion 27 extending from the root portion of the extension portion 23, that is, the portion connected to the core packing attachment portion 21 while being inclined with respect to the axis of the tube end core 17 is formed. In the present embodiment, the inclined portion 27 is an integrated end-spreading portion whose diameter increases as the distance from the core packing attachment portion 21 increases. However, the inclined portion 27 may be divided into a plurality of portions in the circumferential direction. The inclined portion 27 will be described later. The tube end core 17 is attached in a state where the end surface 22 on one side of the core packing attachment portion 21 is in contact with the end surface 15 of the tube 11. As illustrated, the outer diameter of the core packing attachment portion 21 of the pipe end core 17 is smaller than the outer diameter of the pipe 11. In addition, the outer diameter of the core packing 29 attached to the pipe end core 17 is larger than the outer diameter of the core packing attachment portion 21 enough to ensure a compression allowance in a free state, that is, in an uncompressed state. However, it is smaller than the inner diameter of a lock ring 57 and the like which will be described later. In this embodiment, the outer diameter is equal to the outer diameter of the tube 11 or is about 0.2 mm at most.
[0022]
Reference numeral 31 is a mechanical joint, and 33 is the joint body. The joint main body 33 includes a packing storage portion 35 that serves as an insertion port for the pipe 11, and the packing storage portion 35 includes a straight portion 37 that is an end portion side and an inclined portion 39 that is continuous therewith. The straight portion 38 has a substantially cylindrical shape and includes an inner peripheral surface 38 having the same inner diameter, and the inclined portion 39 includes an inner peripheral surface 40 whose inner diameter decreases as the distance from the straight portion 37 increases. On the outer periphery of the straight portion 37, a male screw 41 into which a later-described cap nut 71 is screwed is formed.
[0023]
Reference numeral 43 denotes a tube end storage portion formed subsequent to the packing storage portion 35, which is a portion for storing the end portion 13 of the tube 11 as shown in the drawing, has a substantially cylindrical shape, and has an inner diameter of the tube 11. It is slightly larger than the outer diameter. Reference numeral 45 denotes a substantially cylindrical packing sliding contact portion whose inner diameter is smaller than that of the tube end storage portion 43, and the inner diameter thereof is the same as or slightly larger than the outer diameter of the core packing mounting portion 21 of the tube end core 17. The packing 29 is sufficiently dimensioned to be compressed in the radial direction. The joint main body 33 is further formed with a substantially cylindrical small diameter portion 47 having an inner diameter smaller than the packing sliding contact portion 45. When the pipe 11 is inserted into the pipe joint body 33 by a predetermined length, the tip end portion 28 of the inclined portion 27 of the pipe end core 17 is formed on the end surface 48 of the small diameter portion 47 on the packing sliding contact portion 45 side. It comes to contact.
[0024]
Reference numeral 49 denotes an annular packing that surrounds the periphery of the pipe 1 and is received in the packing storage portion 35 of the joint body 33, and its outer peripheral surface 51 abuts against the inner peripheral surfaces 38 and 40 of the packing storage portion 35. Yes. The inner diameter in the free state is larger than the outer diameter of the tube 11, and there is a slight gap between the inner peripheral surface 53 and the outer peripheral surface of the tube 11 in a state in which a cap nut described later is not yet tightened. .
[0025]
A plate-shaped packing pressing member 55 having both side surfaces substantially parallel to each other is disposed outside the packing 49. The packing pressing member 55 has an annular shape, and its inner diameter is slightly larger than the outer diameter of the tube 11, and the outer diameter is a dimension corresponding to the inner diameter of the straight portion 37 of the packing storage portion 35. It can move along the axial direction of the joint body 33 along the axis.
[0026]
A lock ring 57 is disposed on the opposite side of the packing 49 with the packing pressing member 55 interposed therebetween. The lock ring 57 is formed by dividing an annular member at a certain position in the circumferential direction. In a free state, there is a gap between both ends at that position, and when an external force is applied, the diameter is reduced while closing the gap. It is supposed to be. Since this configuration is known, a detailed description is omitted. A claw 59 is formed on the inner peripheral side of the lock ring 57. Further, the outer peripheral surface 61 is formed on a slope so that the outer diameter decreases as the distance from the packing pressing member 55 increases. The inner diameter of the lock ring 57 in the illustrated state is larger than the outer diameter of the tube 11.
[0027]
Reference numeral 63 denotes an annular lock ring pressing member, and an inner peripheral surface 65 of the inner peripheral surface 65 is a slope corresponding to the outer peripheral surface 61 of the lock ring 57, and is in contact with the lock ring 57 at this portion. The inner diameter of the lock ring pressing member 63 is larger than the outer diameter of the tube 11.
[0028]
Reference numeral 71 denotes a cap nut, and the female screw 73 is attached to the joint main body 33 by being engaged with the male screw 41 of the joint main body 33. As shown in the figure, the cap nut 71 receives the lock ring 57, the lock ring pressing member 63, and the like therein, and the top wall 75 has a hole 77 into which the tube 11 is inserted. The inner side surface 79 of the top wall 75 faces the outer side surface 67 of the lock ring pressing member 63. An annular thin sheet member 81 is arranged between the inner side surface 79 and the outer side surface 67. The sheet member 81 is made of a material having a relatively small friction coefficient, for example, a resin such as Teflon.
[0029]
The procedure for connecting the pipe 11 to the mechanical joint 31 will be described. A packing 49, a packing pressing member 55, a lock ring 57, a lock ring pressing member, a 63 sheet member 81, and a cap nut 71 are illustrated with respect to the mechanical joint body. Assembled in advance in the state, and unitized. In this state, the cap nut 71 need only be screwed to such an extent that it does not come off the main body 33, and it is not necessary to compress the packing 49 by tightening the screw. The pipe end core 17 is attached to the unitized mechanical joint 31, and the pipe 11 fitted with the core packing 29 is inserted. At that time, as described above, the outer diameter of the packing attachment portion 21 of the pipe end core 17 is smaller than the outer diameter of the pipe 11, and the outer diameter of the core packing 29 is equal to or slightly larger than the outer diameter of the pipe 11. Since the outer diameter of the tube 11 is smaller than the inner diameter of the lock ring 57 etc., the lock ring 57 etc. does not hinder the insertion of the tube 11 and the core packing 29 is damaged. Nor. The tube 11 is inserted until the distal end portion 28 of the inclined portion 27 of the tube end core 17 contacts the inner surface 48 of the small diameter portion 47 of the joint body 33.
[0030]
Next, the cap nut 71 is tightened. As the cap nut 71 is tightened against the joint body 33, a pressing force is applied to the sheet member 81, the lock ring pressing member 63, the lock ring 57, the packing pressing member 55, and the packing 49, and the packing 49 is compressed and the outer circumference of the tube 11 is compressed. Crimped onto the surface to seal this part. The lock ring 57 moves in the axial direction, and its diameter decreases, bites the tube 11, and prevents the tube 11 from coming off. When the cap nut 71 is further tightened, the inclined portion 27 of the pipe end core 17 is deformed, so that the pipe 11 is also moved with respect to the joint main body 33 and the packing 49 is further compressed. At that time, since the friction coefficient of the seat member 81 is small, even if the cap nut 71 rotates, a slip occurs between the cap nut 71 and the seat member 81 or between the seat member 81 and the lock ring pressing member 63. The lock ring 57 and the tube 11 are prevented from rotating together with the cap nut 71.
[0031]
【The invention's effect】
As described above in detail, according to the present invention, the mechanical joint is preliminarily assembled, and the pipe end core is attached to the pipe and the pipe with the core packing attached thereto, so that the efficiency of pipe connection work is greatly improved. To do. In this case, since the mechanical joint can be temporarily assembled and managed as a unit, it is extremely convenient as compared with the case where the conventional mechanical parts are managed. In addition, the operation of pulling the tube once inserted by a predetermined length, which has been performed in the past, becomes unnecessary. Further, the pipe is prevented from being rotated when the cap nut is tightened.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an installed state of a pipe and a mechanical joint according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a conventional pipe and mechanical joint.
[Explanation of symbols]
11 Pipe for pipe 17 Pipe end core 21 Packing attachment part 25 Groove 29 Core packing 27 Inclined extension part 31 Mechanical joint 33 Joint body 35 Packing storage part 43 Pipe end storage part 45 Packing sliding contact part 49 Packing 55 Packing pressing member 57 Lock Ring 63 Lock ring pressing member 71 Cap nut 81 Sheet member

Claims

It is a connection structure between a steel water pipe and a mechanical joint,
One end of the tube is provided with an insertion portion that is inserted into the one end of the tube, and a circumferential groove that is located outside the tube and formed on the outer periphery thereof, and has an outer diameter of at least the tube. A pipe end core having a packing receiving portion smaller than the outer diameter at a predetermined length from one end is attached,
A core packing for sealing is received in the circumferential groove of the packing receiving portion,
The mechanical joint includes a hollow joint body that receives the one end side of the pipe from one end side, a packing, a lock ring, and a cap nut that surround the pipe and are sequentially positioned from the one end side of the pipe, By screwing and tightening a cap nut on the joint body, the lock ring is reduced in diameter and moved to the joint body side, and the packing is compressed in the joint body to be brought into close contact with the outer periphery of the pipe. In a connection structure that seals and locks the lock ring to the outer periphery of the pipe and connects the pipe and the mechanical joint,
The joint body has a packing housing portion that receives the packing from the one end side, a pipe receiving portion that receives the tip end portion of the one end side of the pipe, and an inner diameter that is smaller than the packing receiving portion. Is provided with a packing sliding contact portion in which the core packing is in fluid-tight sliding contact with the inner periphery thereof,
The outer diameter of the core packing in the free state received in the circumferential groove is smaller than the inner diameter in the free state of the packing and the lock ring and the inner diameter of the cap nut,
A structure for connecting a steel water pipe and a mechanical joint.

2. The connection structure between a steel water pipe and a mechanical joint according to claim 1, wherein an outer diameter of the core packing in a free state is the same as or slightly larger than an outer diameter of the predetermined length portion of the pipe. A connection structure of a steel water pipe and a mechanical joint, characterized in that

3. The connection structure between a steel water pipe and a mechanical joint according to claim 2, wherein an outer diameter of the core packing in a free state is not more than 0.2 mm larger than an outer diameter of the predetermined length portion of the pipe. Connection structure of steel water pipe and mechanical joint.

2. The connection structure according to claim 1, wherein the joint body includes a small-diameter portion that is formed on a side opposite to the pipe receiving portion with respect to the packing sliding contact portion and has a smaller inner diameter than the packing sliding contact portion. Is further provided with a deformable inclined portion that extends in the axial direction of the tube end core from the packing receiving portion, the tip of which can be brought into contact with the side surface extending in the radial direction of the small diameter portion. Connection structure of steel water pipe and mechanical joint.

5. The connection structure of a steel water pipe and a mechanical joint according to claim 4, wherein when the pipe is inserted into the joint body, a tip of the inclined portion abuts on the side surface of the small-diameter portion, A connection structure of a steel water pipe and a mechanical joint, characterized by positioning relative to the joint body.

6. The connecting device for a steel water pipe and a mechanical joint according to claim 5, wherein the inclined portion of the pipe end core is formed in a divergent shape whose diameter increases toward the end portion. , Steel water pipe and mechanical joint connection structure.

The connection structure between a steel water pipe and a mechanical joint according to claim 6, wherein the inclined portion is divided into a plurality of parts in the circumferential direction. .

The connecting device according to claim 1, wherein the pressing member is disposed between the lock ring and the cap nut, and applies a force from the cap nut to the lock ring when the cap nut is tightened; A connection structure, further comprising a thin sheet member made of a material having a small coefficient of friction, which is disposed between surfaces of the pressing member that exert force on each other.