JP4601912B2

JP4601912B2 - Cylindrical pressure vessel processing method

Info

Publication number: JP4601912B2
Application number: JP2003110756A
Authority: JP
Inventors: 悟美葛本; 久次郎須山
Original assignee: 株式会社モリタユージー
Priority date: 2003-04-15
Filing date: 2003-04-15
Publication date: 2010-12-22
Anticipated expiration: 2023-04-15
Also published as: JP2004314117A

Description

【０００１】
【発明の属する技術分野】
本発明は、円筒状圧力容器とその加工方法及び加工装置に関するものである。
【０００２】
【従来の技術】
消火器は、約１ＭＰａの圧縮ガスを消火薬剤噴射用の圧力源として使用するため、図１１の如く、金属製、特に鋼鉄製の円筒状圧力容器としての消火器容器３１を備えている。消火器容器３１の上端開口縁に形成した口金部３１ａには、圧漏れ防止用のゴム製パッキン３２を装着したバルブ操作部３３をユニオンキャップ３４によって取付けてある。消火器容器３１の口金部３１ａの外周面に形成した螺子山（図示略）には、消火器内の圧縮ガスによる負荷がバルブ操作部３３及びユニオンキャップ３４を介して作用する。このため、消防法では、上記負荷に耐え得る螺子山を形成できるように、口金部３１ａの有効肉厚（円筒状胴部の内径が１２０ｍｍ未満の場合は１．０ｍｍ以上、円筒状胴部の内径が１２０ｍｍ以上の場合は１．２ｍｍ以上）を規定している。
【０００３】
図１１の消火器容器３１は、図１２（Ａ）の如く、所定厚に形成した口金部３１ａと、鋼板をプレス加工により絞り成形した天板３１ｂと、鋼板をロール加工すると共に縦溶接Ａにより円筒状に形成した胴部３１ｃと、鋼板をプレス加工により絞り成形した底板３１ｄとからなり、胴部３１ｃの両端開口部に天板３１ｂ及び底板３１ｄを溶着すると共に、天板３１ｂの鏡面部を打ち抜いてその孔３１ｅの周縁部に口金部３１ａを溶着したものである。
【０００４】
また、従来の消火器容器には、図１２（Ｂ）（Ｃ）の如く、３つの鋼鉄製の部材で構成したものもある。図１２（Ｂ）の消火器容器は、胴部３１ｃの両端開口部に、口金部３１ａを一体に成形した天板３１ｂと底板３１ｄとを溶着したものである（例えば特許文献１参照）。図１２（Ｃ）の消火器容器は、所定厚に形成した口金部３１ａと、鋼板をプレス加工により深絞り成形した上側部材３１ｆ及び下側部材３１ｇとからなり、上側部材３１ｆ及び下側部材３１ｇの開口端部を突き合わせて溶着すると共に、上側部材３１ｆの鏡面部を打ち抜いてその孔３１ｅの周縁部に口金部３１ａを溶着したものである。
【０００５】
【特許文献１】
特開平８−２６７１６１号公報（図１Ｂ参照）
【０００６】
【発明が解決しようとする課題】
消火器容器を製造するに際しては、従来から溶接工程中に溶接不良による圧漏れが発生するという問題があった。図１２（Ａ）の消火器容器の製造中に発生した溶接不良による圧漏れの件数を調べたところ、１００，０００本中９０７本（約０．９％）に圧漏れが見られた。図１２（Ａ）の消火器容器の各溶接箇所Ａ〜Ｄの圧漏れ件数を表１に示す。
【０００７】
【表１】

【０００８】
表１から、図１２（Ａ）の消火器容器で発生した圧漏れの約９６％が、胴部３１ｃの縦溶接Ａ又は天板３１ｂ及び胴部３１ｃの突合せ溶接Ｂのいずれかで発生していることが分かる。胴部３１ｃの縦溶接Ａの圧漏れは、その殆どが縦溶接Ａの上下端部で発生している。胴部３１ｃの縦溶接Ａの上下端部で溶接不良が多いのは、鋼板から胴部３１ｃを形成するときと、胴部３１ｃに天板３１ｂ及び底板３１ｄを接合するときの２度に渡って溶接しているために、その近傍の溶接箇所と比較して溶接による変形度合が大きくなっているからである。天板３１ｂ及び胴部３１ｃの突合せ溶接Ｂの圧漏れは、図１１の如く、天板３１ｂ及び胴部３１ｃの肉厚差が原因になっている。天板３１ｂが胴部３１ｃよりも厚いのは、絞り成形により展延した天板３１ｂの鏡面部、特にその孔３１ｅの周縁部を口金部３１ａの有効肉厚に対応して所定厚に形成するために、口金部３１ａよりも肉厚の鋼板から天板３１ｂを成形する一方で、消火器容器の軽量化を図るために薄い鋼板から胴部３１ｃを成形しているからである。
【０００９】
図１２（Ｂ）の消火器容器は、同図（Ａ）の消火器容器の円周溶接Ｄがないものであるが、表１の如く円周溶接Ｄの圧漏れ件数が少ないことから、同図（Ａ）の消火器容器と比較しても圧漏れ発生率に大差がない。同図（Ｃ）の消火器容器は、最も圧漏れし易い縦溶接Ａがないので、同図（Ａ）（Ｂ）の消火器容器と比較して圧漏れ発生率が低くなる。しかし、同図（Ｃ）の消火器容器は、上側部材３１ｆの鏡部３１ｅを口金部３１ａに対応した厚さに形成するために、同図（Ａ）（Ｂ）の天板３１ｂとなる鋼板よりも肉厚の鋼板から上側部材３１ｆを成形しているので、同図（Ａ）（Ｂ）のものと比較して肉厚部分が多いために重くなるという問題があった。
【００１０】
また、鋼鉄製以外の消火器容器、例えば樹脂製やアルミ製の消火器容器には、溶接箇所が一箇所のものや溶接箇所がないものもあった。これらの消火器容器には、軽量で、かつ、溶接不良により圧漏れが発生し難い（発生しない）という利点がある反面、耐久性が低く、しかも製造コストが嵩むという問題があった。
【００１１】
本発明はかかる課題に鑑み創案するに至ったものであって、その目的は、軽量で、かつ、溶接不良による圧漏れが発生し難い鋼鉄製の円筒状圧力容器を提供することにある。
【００１２】
【課題を解決するための手段】
本発明に係る円筒状圧力容器の加工方法は、円筒状胴部の下端部から口金部までを一体に成形した容器本体と、該容器本体の下端開口部を閉塞する底板との２部材を接合してなる鋼鉄製の円筒状圧力容器の加工方法であって、へら絞り加工機の回転軸の一端のチャックによって鋼鉄製のパイプ材をチャックすると共に、２個の前記容器本体の口金部を突き合わせた状態での該口金部の内面形状に対応した形状部を有する２個一組のコア部材を前記パイプ材の内径に対向状態で嵌合し、該２個一組のコア部材の相対向する先端部にはそれぞれ凹部と凸部が設けられており、一方の前記コア部材の凸部が他方の前記コア部材の凹部に移動自在に嵌入され、前記パイプ材をその軸線回りに回転させると共に、前記パイプ材に対してその軸線方向に圧縮力を付加した状態で、前記コア部材の前記形状部に対応する前記パイプ材の所定部分の外周面を絞り手段で押圧しつつ軸線方向に往復移動させることにより、前記パイプ材の所定部分を縮径させると共に前記コア部材の前記形状部に押圧して、前記口金部となる縮径肥肉化部を形成ようにしている。
【００１３】
本発明によれば、円筒状胴部の下端部から口金部までを一体に成形した容器本体をパイプ材から成形しているので、従来のものと比較して溶接の少ない鋼鉄製の円筒状圧力容器を製造できる。特に図１２（Ａ）（Ｂ）に示す胴部３１ｃの縦溶接Ａと、天板３１ｂ及び胴部３１ｃの突合せ溶接Ｂとを省いているので、溶接不良による圧漏れを大幅に低減できる。パイプ材としては、縦溶接Ａの不要なシームレス管が最適であるが、コスト面を考慮すると縦溶接Ａの上下端部の溶接不良が少ない電縫溶接管でも構わない。
【００１４】
円筒状圧力容器の軽量化は、その大部分を占める容器本体を所要の耐圧力が得られる範囲内で薄く形成することにより達成できるが、その際、容器本体の口金部の有効肉厚に留意する必要がある。一般的なプレス加工やへら絞り加工によって、金属材料を塑性変形させると、当該変形部分が展延して薄くなる。本発明では、パイプ材の軸線方向に圧縮力を付加しつつへら絞り加工しているので、パイプ材の変形部分、即ち縮径部分は、展延による強度の低下及び上記圧縮力の加圧断面積の狭小化によって、単位断面積当りの上記圧縮力が非加工部分よりも大きくなるために、軸線方向に圧縮されて短くなる。パイプ材の圧縮分の肉は、パイプ材の縮径部分から非加工部分へ逃げないようにパイプ材の外周面を絞り手段で押圧しつつ軸線方向に移動させることにより、パイプ材の縮径部分の内部で分散する。これによりパイプ材の一部に容器本体の口金部となる縮径肥肉化部を形成できる。この場合、パイプ材の非加工部分が容器本体の円筒状胴部になるから、加工前のパイプ材として所要の耐圧性が得られる範囲内で薄いものを使用することにより、円筒状圧力容器の軽量化を図ることができる。容器本体の口金部の厚さは、パイプ材の圧縮長を変更することにより適宜設定でき、パイプ材が薄くてもその圧縮長を長くすることで口金部の有効肉厚を確保できる。
【００１５】
また、２個の容器本体の口金部を突き合わせた状態での該口金部の内面形状に対応した形状部を有する２個一組のコア部材をパイプ材の内径に対向状態で嵌合し、パイプ材の所定部分を縮径させると共にコア部の前記形状部に押圧して縮径肥肉化部を形成するので、パイプ材の縮径肥肉化部を所期の形状及び肉厚に加工することができる。さらに、該縮径肥肉化部の中央部でパイプ材を切断すると、同時に２個の容器本体を作製することができる。なお、コア部材の形状は、２個一組で、２個の円筒状容器の口金部を突き合せた状態の内面形状と同形状になればよく、２個のコア部材が相違する形状であっても構わない。
【００１７】
また、絞り手段による押圧力を、絞り手段がパイプ材の所定部分の外側部分から中央部分に向かって移動するときと、絞り手段がパイプ材の所定部分の中央部分から外側部分に向かって移動するときとで変えるようにしても良い。
【００１８】
【発明の実施の形態】
以下、図面を参照しつつ本発明に係る円筒状圧力容器とその加工方法及び加工装置について説明する。なお、本実施形態では、円筒状圧力容器として消火器容器を用いて説明する。
【００１９】
図１は、本発明に係る加工方法を使用して製造した鋼鉄製の消火器容器１を備えた消火器を例示している。この消火器容器１は、同図の如く、円筒状胴部２ａの下端部からその上端開口縁の口金部２ｂまでを一体に成形した容器本体２と、容器本体２の下端開口部に嵌合する底板３とからなり、容器本体２に底板３を嵌合させた状態で円周溶接により接合してある。容器本体２は、口金部２ｂを有効肉厚（円筒状胴部の内径が１２０ｍｍ未満の場合は１．０ｍｍ以上、円筒状胴部の内径が１２０ｍｍ以上の場合は１．２ｍｍ以上）で、かつ、円筒状胴部２ａよりも肉厚に形成してある。底板３は、鋼板をプレス加工又はへら絞り加工などの周知の加工方法により所定形状に成形したものである。
【００２０】
図２は、本発明に係る加工方法を使用した加工装置１１を例示している。この加工装置１１は、鋼鉄製のパイプ材２’をその軸線回りに回転駆動する回転駆動手段１２と、パイプ材２’の軸線方向に圧縮力を付加する加圧手段１３と、パイプ材２’の外周面を押圧して縮径肥肉化させる絞り手段１４と、パイプ材２’を切断する切断手段１５（図９参照）とを備え、鋼鉄製のパイプ材２’から２個の容器本体２を同時に成形するものである。
【００２１】
回転駆動手段１２は、ベース１７の片端上面部に立設した固定支柱１２ａの内側面に設けた図示外の回転軸に駆動チャック１２ｂを設けたものである。駆動チャック１２ｂは、パイプ材２’の片端部を把持固定すると共にその軸線回りに回転駆動し、パイプ材２’を同期して回転させる。駆動チャック１２ｂの端面には、コア部材１８を脱着可能に取付けてある。
【００２２】
加圧手段１３は、固定支柱１２ａと対向してベース１７上に立設した可動支柱１３ａの内側面に従動チャック１３ｂを設けたものである。可動支柱１３ａは、固定支柱１２ａと接近離間する直線運動要素である。従動チャック１３ｂの端面には、パイプ材２’に嵌入させるコア部材１９を脱着可能に取付けてある。従動チャック１３ｂは、パイプ材２’の端部にコア部材１９を嵌入してその端面をパイプ材２’の端部に接触させ、パイプ材２’を介して伝達される駆動チャック１２ｂの駆動力によって回転する。
【００２３】
コア部材１８，１９は、同一軸線上に配設され、２個一組で、図１に示す容器本体２を２個用意し、各々の口金部２ｂを突き合せた状態の内面形状に対応した形状に形成してある。具体的には、コア部材１８は、容器本体２の円筒状胴部２ａから口金部２ｂの根元部分に至る内面形状に対応した形状になっており、コア部材１９は、２個の容器本体２の口金部２ｂを突き合せた状態で一方の容器本体２の口金部２ｂの根元部分から他方の容器本体２の円筒状胴部２ａの下端部に至る内面形状に対応した形状になっている。また、コア部材１８の先端面には、コア部材１９の先端部に突設した凸部１９ａを嵌入するための凹部１８ａを穿設してある。
【００２４】
絞り手段１４は、パイプ材２’の軸線直交方向及び軸線方向に移動しつつパイプ材２’の外周面を押圧するスピニングローラで、パイプ材２’の軸線方向との角度を任意の角度に変更可能になっている。
【００２５】
切断手段１５は、図９の如く、パイプ材２’の外周面を軸線直交方向に押圧する切断バイトである。
【００２６】
次に、図３乃至図９を参照しつつ本発明に係る円筒状容器の加工方法を使用して消火器容器を製造する工程について説明する。
【００２７】
まず、図３の如く、パイプ材２’をその片端開口部から回転駆動手段１２の駆動チャック１２ｂに取付けたコア部材１８に嵌入すると共に駆動チャック１２ｂによってパイプ材２’の片端部を把持固定する。この状態から加圧手段１３を駆動して回転駆動手段１２に接近させ、図４の如く、加圧手段１３の従動チャック１３ｂに取付けたコア部材１９をパイプ材２’の他端開口部に嵌入すると共に、従動チャック１３ｂの端面をパイプ材２’の他端部に接触させる。図４の状態では、パイプ材２’の開口端部が駆動チャック１２ｂ及び従動チャック１３ｂの端面に接触しているが、コア部材１９の凸部１９ａは、その先端部がコア部材１８の凹部１８ａに嵌入しているだけである。このため、コア部材１８の先端部とコア部材１９の凸部１９ａの根元部分との間に間隔ｄ₀が設けられている。この状態で、更に可動支柱１３ａを回転駆動手段１２側へ駆動すると、パイプ材２’の軸芯方向に圧縮力を付加することができる。
【００２８】
図５及び図６は、パイプ材２’の縮径肥肉化工程を示している。図５の如く、回転駆動手段１２によりパイプ材２’をその軸線回りに回転させると共に加圧手段１３によりパイプ材２’の軸芯方向に圧縮力を付加した状態で、絞り手段１４をパイプ材２’の軸線直交方向に往復動させてパイプ材２’の外周面中央部を叩くことによりパイプ材２’の中央部を窪ませて粗加工する。次に、図６の如く、絞り手段１４をパイプ材２’の軸線方向に往復動させつつパイプ材２’の外周面を押圧する。これにより、図７の如く、パイプ材２’の中央部に縮径肥肉化部２ｂ’を形成できる。
【００２９】
図５及び図６の工程では、パイプ材２’の中央部は、縮径した際に展延するから、当該縮径部分の強度が低下する。また、パイプ材２’の縮径部分に作用する単位断面積当りの圧縮力は、非加工部分２ａ’よりも大きくなる。これによりパイプ材２’の縮径部分が軸芯方向に圧縮され、図４乃至図７に示す如く、コア部材１８の先端部とコア部材１９の凸部１９ａの根元部分との間の間隔がｄ₀→ｄ₁→ｄ₂→ｄ₃の順に徐々に狭まっていく。図５及び図６の工程で、パイプ材２’の圧縮分の肉は、パイプ材２’の縮径部分の範囲内で分散する。その結果、当該縮径部分が、図７の如く、パイプ材２’の非加工部分２ａ’よりも肉厚の縮径肥肉化部２ｂ’となる。縮径肥肉化部２ｂ’は、その中央部が最も肉厚で、非加工部分２ａ’に近付くにつれて徐々に薄くなっている。これは、縮径肥肉化部２ｂ’の中央部で上記圧縮力がパイプ材２’の軸芯方向に最も大きく作用するからである。また、縮径肥肉化部２ｂ’の厚さは、パイプ材２’の圧縮長（ｄ₀−ｄ₃）を変更することにより適宜設定でき、パイプ材２’が薄くても前記圧縮長を長くすることで縮径肥肉化部２ｂ’を肉厚に形成できる。
【００３０】
なお、図６の工程では、絞り手段１４の移動方向及び位置によって押圧力を適宜変更しても構わない。例えば絞り手段１４がパイプ材２’の外側から中央部に向かって移動するときはパイプ材２’を強く押圧し、かつ、パイプ材２’の中央部から外側へ移動するときは弱く押圧することで、縮径肥肉化部２ｂ’の中央部の肥肉化を促進でき、またこの逆の動作により縮径肥肉化部２ｂ’の中央部の過厚分を分散させることもできる。これによりパイプ材２’の縮径肥肉化部２ｂ’の外形状を所期の形状に形成することができる。パイプ材２’の内形状は、コア部材１８，１９の形状によって定まるから、パイプ材２’の縮径肥肉化部２ｂ’の外形状を所期の形状に形成することで、当該縮径肥肉化部２ｂ’を所期の肉厚に形成できる。
【００３１】
また、図７の縮径肥肉化工程が終了した段階で、コア部材１８の先端部とコア部材１９の凸部１９ａの根元部分との間に間隔ｄ₃（例えば数ｍｍ程度）を開けておくことで、縮径肥肉化工程が終了するまでの間中、パイプ材２’に圧縮力を付加し続けることができる。なお、縮径肥肉化工程の終了時にコア部材１８の先端部とコア部材１９の凸部１９ａの根元部分との間の間隔をなくすようにしても構わない。
【００３２】
図８及び図９は、パイプ材２’の切断工程を示している。パイプ材２’の回転を停止させた状態で、図８の如く、可動支柱１３ａを固定支柱１２ａから離間させ、コア部材１８の先端部とコア部材１９の凸部１９ａの根元部分との間に間隔ｄ₄を開ける。この間隔ｄ₄は、縮径肥肉化部２ｂ’の長さの１／２以上である。これにより縮径肥肉化部２ｂ’の中央部に中空部２０を設けることができる。そして、図９の如く、回転駆動手段１２によりパイプ材２’を回転させた状態で、切断手段１５をパイプ材２’の縮径肥肉化部２ｂ’の中央部に接触させてパイプ材２’を切断する。
【００３３】
上記の各工程を経て、同時に２個の容器本体２を成形することができる。そして、各容器本体２を加工装置１１から取り外し、円筒状胴部２ａ側の開口端部に、図１の如く、底板３を円周溶接により接合する工程と、口金部２ｂの外周部に雄ねじを形成する工程と、口金部２ｂの端部、即ちパイプ材２’の切断面を研磨して面取りする工程とを経て消火器容器１が出来上がる。
【００３４】
以上、本発明の一実施形態につき説明したが、本発明は前記実施形態に限定されることなく種々の変形が可能であって、例えば上記実施形態では、回転駆動手段１２をベース１７上に固定したものを示したが、回転駆動手段１２を加圧手段１３と同様の直線運動要素としても構わない。この場合、回転駆動手段１２も加圧手段の構成要素となり、パイプ材２’に対して圧縮力を左右対称に作用させることができる。これにより同時に加工した２個の容器本体２の形状誤差を低減させることができる。
【００３５】
また、上記実施形態では、加圧手段１３の従動チャック１３ｂに駆動機構を設けていないが、従動チャック１３ｂにパイプ材２’の把持機構及び駆動機構を設けても構わない。この場合、パイプ材２’を切断して２個の容器本体２に分けた後であっても、駆動チャック１２ｂ及び従動チャック１３ｂによって各容器本体２を把持固定すると共にその軸線回りに回転させることができる。これにより、パイプ材２’の切断工程の後に続けて容器本体２の切断面の面取り工程を行なえる。
【００３６】
また、上記実施形態では、パイプ材２’を切断したのち、口金部２ｂにねじ切り加工を施したが、図１０の如く、パイプ材２’を切断する前に縮径肥肉化部２ｂ’のねじ切り工程を行なっても構わない。ねじ切り工程は、回転駆動手段１２によりパイプ材２’を回転させた状態で、パイプ材２’の縮径肥肉化部２ｂ’の外周面をねじ切り手段１６で押圧しつつねじ切り手段１６をパイプ材２’の軸線方向に移動させて、縮径肥肉化部２ｂ’に雄ねじを形成する。ねじ切り手段１６は、図１０の如く、パイプ材２’の外周面を軸線直交方向に押圧するねじ切りバイトである。この場合、切断工程で切断する縮径肥肉化部２ｂ’の中央部には、雄ねじを形成する必要はない。
【００３７】
また、上記実施形態では、コア部材１８，１９を容器本体２の内面形状に対応した形状に形成したものを挙げて説明したが、コア部材１８，１９は、少なくとも容器本体２の円筒状胴部２ａの上端から口金部２ｂに至る部分、即ち縮径肥肉化加工を施した部分の内面形状に対応したものであればよく、容器本体２の円筒状胴部２ａに対応する部分の形状については、円筒状胴部２ａの内径よりも小径であっても構わない。
【００３８】
また、上記実施形態では、異なる形状のコア部材１８，１９を挙げて説明したが、これらは同一形状であっても構わない。この場合、コア部材１８，１９をパイプ材２’の軸線方向に進退自在に構成することで、パイプ材２’を切断する際に縮径肥肉化部２ｂ’の中央部に中空部２０を形成できる。
【００３９】
なお、本実施形態では、円筒状圧力容器として消火器容器を挙げて説明したが、円筒状圧力容器としては、圧縮ガスを封入したガスボンベもある。
【００４０】
【発明の効果】
本発明の加工方法は前述の如く、容器本体の円筒状胴部の下端部から口金部までを溶接なしで一体に成形したので、該容器本体と底板の円周溶接のみで鋼鉄製の円筒状圧力容器を製造できる。すなわち、従来の製造方法と比較して溶接箇所が少なくなるから、円筒状圧力容器の溶接不良による圧漏れを低減でき、しかもその美観を向上させることができる。
【００４１】
鋼鉄製のパイプ材をその軸線回りに回転させると共に、パイプ材に対してその軸線方向に圧縮力を付加した状態で、パイプ材の外周面を絞り手段で押圧しつつ軸線方向に移動させたので、パイプ材の一部に縮径肥肉化部を形成できる。これによりパイプ材の非加工部分を円筒状胴部とし、かつ、縮径肥肉化部を口金部とする円筒状圧力容器の容器本体を形成でき、縮径肥肉化部がパイプ材の非加工部分よりも肉厚であることから、容器本体の口金部の有効肉厚を確保しつつ円筒状胴部を薄く形成できる。このように円筒状圧力容器の大部分を占める容器本体を軽量にすることができるから、軽量な円筒状圧力容器を提供可能になる。
【００４２】
しかも、パイプ材の所定部分を縮径させると共にコア部材の形状部に押圧して、口金部となる縮径肥肉化部を形成するので、縮径肥肉化部、ひいては口金部を所期の形状及び肉厚に形成することができ、また、パイプ材を縮径肥肉化部で切断することにより２個の容器本体を同時に形成することができる。
【００４３】
２個一組のコア部材の相対向する先端部にそれぞれ凹部と凸部を設け、一方のコア部材の凸部を他方のコア部材の凹部に移動自在に嵌入した構成とすることにより、２個一組のコア部材の同軸度を確保して、加工精度を高めることができる。また、絞り手段による押圧力を、絞り手段がパイプ材の所定部分の外側部分から中央部分に向かって移動するときと、絞り手段がパイプ材の所定部分の中央部分から外側部分に向かって移動するときとで変えることにより、縮径肥肉化部、ひいては口金部の形状及び肉厚の精度を高めることができる。
【図面の簡単な説明】
【図１】本発明に係る加工方法を使用して製造した消火器容器を例示する縦断面図である。
【図２】本発明に係る加工方法を使用した加工装置を例示する模式図である。
【図３】パイプ材を回転駆動手段に取付ける工程を示す模式図である。
【図４】パイプ材を回転駆動手段に取付けた状態を示す模式図である。
【図５】パイプ材の縮径肥肉化工程の粗加工を示す模式図である。
【図６】パイプ材の縮径肥肉化工程の仕上げ加工を示す模式図である。
【図７】パイプ材の縮径肥肉化部を示す縦断面図である。
【図８】パイプ材のねじ切り工程を示す模式図である。
【図９】パイプ材の切断工程を示す模式図である。
【図１０】パイプ材の切断工程を示す模式図である。
【図１１】従来の消火器容器を例示する縦断面図である。
【図１２】（Ａ）は、図１１の消火器容器の加工方法を例示する模式図で、（Ｂ）及び（Ｃ）は、他の加工方法を示す模式図である。
【符号の説明】
１消火器容器
２容器本体
２ａ円筒状胴部
２ｂ口金部
２’ パイプ材
２ｂ’ 縮径肥肉化部
３底板
１１加工装置
１２回転駆動手段
１２ｂ駆動チャック
１３加圧手段
１３ｂ従動チャック
１４絞り手段
１５切断手段
１８，１９コア部材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cylindrical pressure vessel, a processing method thereof, and a processing apparatus.
[0002]
[Prior art]
Since the fire extinguisher uses compressed gas of about 1 MPa as a pressure source for extinguishing a fire extinguishing agent, the fire extinguisher includes a fire extinguisher container 31 as a cylindrical pressure container made of metal, particularly steel, as shown in FIG. A valve operating part 33 fitted with a rubber packing 32 for preventing pressure leakage is attached to a base part 31 a formed at the upper end opening edge of the fire extinguisher container 31 by a union cap 34. A load of compressed gas in the fire extinguisher acts on a screw thread (not shown) formed on the outer peripheral surface of the base part 31 a of the fire extinguisher container 31 via the valve operating part 33 and the union cap 34. For this reason, in the Fire Service Act, the effective thickness of the base 31a (1.0 mm or more when the inner diameter of the cylindrical body is less than 120 mm, If the inner diameter is 120 mm or more, it is defined as 1.2 mm or more).
[0003]
As shown in FIG. 12A, the fire extinguisher container 31 of FIG. 11 includes a base 31a formed to a predetermined thickness, a top plate 31b obtained by drawing a steel plate by press working, and rolling the steel plate and performing vertical welding A. The body 31c is formed in a cylindrical shape, and a bottom plate 31d is formed by drawing a steel plate by press working. The top plate 31b and the bottom plate 31d are welded to both end openings of the body 31c, and the mirror surface portion of the top plate 31b is provided. The die 31a is welded to the peripheral edge of the hole 31e.
[0004]
In addition, some conventional fire extinguisher containers are composed of three steel members as shown in FIGS. The fire extinguisher container of FIG. 12 (B) is obtained by welding a top plate 31b and a bottom plate 31d integrally formed with a base part 31a to both end openings of a body part 31c (see, for example, Patent Document 1). The fire extinguisher container of FIG. 12C includes a base part 31a formed to a predetermined thickness, and an upper member 31f and a lower member 31g obtained by deep drawing a steel plate by press working, and the upper member 31f and the lower member 31g. The opening end portions of the upper member 31f are abutted and welded, and the mirror surface portion of the upper member 31f is punched to weld the base portion 31a to the peripheral portion of the hole 31e.
[0005]
[Patent Document 1]
JP-A-8-267161 (see FIG. 1B)
[0006]
[Problems to be solved by the invention]
When manufacturing a fire extinguisher container, there has conventionally been a problem that pressure leakage due to poor welding occurs during the welding process. When the number of pressure leaks due to poor welding that occurred during the manufacture of the fire extinguisher container of FIG. 12 (A) was examined, 907 out of 100,000 pieces (about 0.9%) showed pressure leaks. Table 1 shows the number of pressure leaks at each welding point A to D of the fire extinguisher container of FIG.
[0007]
[Table 1]

[0008]
From Table 1, about 96% of the pressure leakage that occurred in the fire extinguisher container of FIG. 12 (A) occurred in either the longitudinal welding A of the trunk 31c or the butt weld B of the top plate 31b and the trunk 31c. I understand that. Most of the pressure leakage of the vertical welding A of the trunk portion 31c occurs at the upper and lower ends of the vertical welding A. There are many welding defects at the upper and lower ends of the longitudinal welding A of the body 31c when the body 31c is formed from the steel plate and when the top plate 31b and the bottom plate 31d are joined to the body 31c. This is because, since welding is performed, the degree of deformation due to welding is larger than that in the vicinity of the welded portion. The pressure leakage of the butt weld B between the top plate 31b and the body portion 31c is caused by the difference in thickness between the top plate 31b and the body portion 31c as shown in FIG. The reason why the top plate 31b is thicker than the body portion 31c is that the mirror surface portion of the top plate 31b expanded by drawing, particularly the peripheral edge portion of the hole 31e, is formed with a predetermined thickness corresponding to the effective thickness of the base portion 31a. Therefore, while the top plate 31b is formed from a steel plate thicker than the base portion 31a, the trunk portion 31c is formed from a thin steel plate in order to reduce the weight of the fire extinguisher container.
[0009]
The fire extinguisher container of FIG. 12 (B) does not have the circumferential weld D of the fire extinguisher container of FIG. 12 (A), but the number of pressure leaks of the circumferential weld D as shown in Table 1 is small. Even when compared with the fire extinguisher container of FIG. Since the fire extinguisher container of FIG. 10C does not have the vertical weld A that is most likely to cause pressure leak, the rate of occurrence of pressure leak is lower than that of the fire extinguisher container of FIGS. However, the fire extinguisher container of FIG. 6C is a steel plate that forms the top plate 31b of FIGS. 6A and 6B in order to form the mirror portion 31e of the upper member 31f with a thickness corresponding to the base portion 31a. Since the upper member 31f is formed from a thicker steel plate, there is a problem that it is heavier because there are more thick portions than those shown in FIGS.
[0010]
Moreover, some fire extinguisher containers other than steel, for example, resin or aluminum fire extinguisher containers, have one welded part or no welded part. These fire extinguisher containers are light in weight and have the advantage that pressure leakage does not easily occur due to poor welding (does not occur), but there is a problem that durability is low and manufacturing cost increases.
[0011]
The present invention has been invented in view of such problems, and an object of the present invention is to provide a steel cylindrical pressure vessel that is light in weight and hardly causes pressure leakage due to poor welding.
[0012]
[Means for Solving the Problems]
The processing method of the cylindrical pressure vessel according to the present invention is a method of joining two members, a container body integrally formed from the lower end portion of the cylindrical body portion to the base portion, and a bottom plate that closes the lower end opening portion of the container body. A steel cylindrical pressure vessel processing method, in which a steel pipe material is chucked by a chuck at one end of a rotary shaft of a spatula drawing machine, and the cap portions of two container bodies are butted together A set of two core members having a shape corresponding to the inner surface shape of the base portion in a state of being connected is fitted to the inner diameter of the pipe material in a facing state, and the two sets of core members are opposed to each other. Each of the tip portions is provided with a recess and a protrusion, the protrusion of one of the core members is movably fitted into the recess of the other core member, and the pipe member is rotated around its axis, Pressure in the axial direction against the pipe material With the force applied, the predetermined portion of the pipe member is contracted by reciprocating in the axial direction while pressing the outer peripheral surface of the predetermined portion of the pipe member corresponding to the shape portion of the core member with the squeezing means. A diameter-reduced and thickened portion to be the base portion is formed by pressing the shape portion of the core member and making the diameter portion.
[0013]
According to the present invention, since the container body formed integrally from the lower end portion of the cylindrical body portion to the base portion is formed from the pipe material, the cylindrical pressure made of steel with less welding compared to the conventional one. A container can be manufactured. In particular, since the longitudinal welding A of the body 31c and the butt welding B of the top plate 31b and the body 31c shown in FIGS. 12A and 12B are omitted, pressure leakage due to poor welding can be greatly reduced. As the pipe material, a seamless pipe that does not require vertical welding A is optimal. However, in consideration of cost, an electric resistance welded pipe that has few welding defects at the upper and lower ends of the vertical welding A may be used.
[0014]
The weight reduction of the cylindrical pressure vessel can be achieved by forming the container body that occupies most of the container within the range where the required pressure resistance can be obtained, but at that time, pay attention to the effective thickness of the base part of the container body. There is a need to. When a metal material is plastically deformed by general press working or spatula drawing, the deformed portion is spread and thinned. In the present invention, the spatula is drawn while applying a compressive force in the axial direction of the pipe material. Therefore, the deformed portion of the pipe material, that is, the reduced diameter portion, is caused by a decrease in strength due to spreading and the pressure breaking of the compressive force. Due to the narrowing of the area, the compression force per unit cross-sectional area becomes larger than that of the non-processed portion, so that it is compressed and shortened in the axial direction. The compressed part of the pipe material is moved in the axial direction while pressing the outer peripheral surface of the pipe material with the squeezing means so that it does not escape from the reduced diameter part of the pipe material to the non-processed part. Distributed within. Thereby, the reduced diameter thickening part used as the nozzle | cap | die part of a container main body can be formed in a part of pipe material. In this case, since the non-processed portion of the pipe material becomes the cylindrical body portion of the container body, by using a thin pipe material within a range where the required pressure resistance can be obtained as the pipe material before processing, Weight reduction can be achieved. The thickness of the base part of the container body can be appropriately set by changing the compression length of the pipe material, and even if the pipe material is thin, the effective thickness of the base part can be secured by increasing the compression length.
[0015]
A pair of core members having a shape corresponding to the shape of the inner surface of the base in a state in which the bases of the two container bodies are butted together are fitted to the inner diameter of the pipe material in a facing state; Since the predetermined portion of the material is reduced in diameter and pressed against the shape portion of the core portion to form the reduced diameter thickened portion, the reduced diameter thickened portion of the pipe material is processed into the desired shape and thickness . be able to. Moreover, when cutting the pipe in the center portion of the fused径肥meat section, it is possible to produce two container body at the same time. The shape of the core members may be the same shape as the shape of the inner surface of the pair of two cylindrical containers that are in contact with the base portions of the two cylindrical containers. It doesn't matter.
[0017]
Further, the pressing force by the squeezing means moves when the squeezing means moves from the outer portion of the predetermined portion of the pipe material toward the central portion, and when the squeezing means moves from the central portion of the predetermined portion of the pipe material toward the outer portion. It may be changed depending on the time.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a cylindrical pressure vessel, a processing method thereof, and a processing apparatus according to the present invention will be described with reference to the drawings. In the present embodiment, a fire extinguisher container is used as the cylindrical pressure container.
[0019]
FIG. 1 illustrates a fire extinguisher equipped with a steel fire extinguisher container 1 manufactured using the processing method according to the present invention. As shown in the figure, the fire extinguisher container 1 is fitted into a container body 2 integrally formed from a lower end portion of a cylindrical body 2a to a base portion 2b of an upper end opening edge thereof, and a lower end opening portion of the container body 2 The bottom plate 3 is joined to the container body 2 by circumferential welding with the bottom plate 3 fitted. The container body 2 has an effective thickness of the base portion 2b (1.0 mm or more when the inner diameter of the cylindrical body is less than 120 mm, 1.2 mm or more when the inner diameter of the cylindrical body is 120 mm or more), and The wall is formed thicker than the cylindrical body 2a. The bottom plate 3 is obtained by forming a steel plate into a predetermined shape by a known processing method such as pressing or spatula drawing.
[0020]
FIG. 2 illustrates a processing apparatus 11 using the processing method according to the present invention. This processing apparatus 11 includes a rotation driving means 12 for rotating and driving a steel pipe material 2 ′ around its axis, a pressurizing means 13 for applying a compressive force in the axial direction of the pipe material 2 ′, and a pipe material 2 ′. Squeezing means 14 for pressing and reducing the diameter of the outer peripheral surface and cutting means 15 for cutting the pipe material 2 ′ (see FIG. 9), and two container bodies from the steel pipe material 2 ′. 2 are molded simultaneously.
[0021]
The rotation drive means 12 is provided with a drive chuck 12b on a rotation shaft (not shown) provided on the inner surface of a fixed column 12a erected on the upper surface of one end of the base 17. The drive chuck 12b grips and fixes one end portion of the pipe material 2 ′ and is driven to rotate about the axis thereof to rotate the pipe material 2 ′ in synchronization. A core member 18 is detachably attached to the end surface of the drive chuck 12b.
[0022]
The pressurizing means 13 is provided with a follower chuck 13b facing the fixed column 12a and the inner surface of the movable column 13a standing on the base 17. The movable column 13a is a linear motion element that approaches and separates from the fixed column 12a. A core member 19 to be fitted into the pipe material 2 ′ is detachably attached to the end face of the driven chuck 13b. The driven chuck 13b has a core member 19 fitted into the end of the pipe member 2 ', the end surface thereof is brought into contact with the end of the pipe member 2', and the driving force of the drive chuck 12b transmitted through the pipe member 2 '. Rotate by.
[0023]
The

core members

18 and 19 are disposed on the same axis, and two sets of the container main bodies 2 shown in FIG. 1 are prepared as a set, and correspond to the inner surface shape in a state where the base portions 2b are abutted with each other. It is formed into a shape. Specifically, the core member 18 has a shape corresponding to the shape of the inner surface from the cylindrical body portion 2a of the container body 2 to the root portion of the base portion 2b, and the core member 19 includes two container bodies 2. The shape corresponding to the inner surface shape from the base part of the base part 2b of one container body 2 to the lower end part of the cylindrical body part 2a of the other container body 2 in a state where the base part 2b of the container body 2 is abutted. Further, a concave portion 18 a for fitting a convex portion 19 a protruding from the distal end portion of the core member 19 is formed in the distal end surface of the core member 18.
[0024]
The squeezing means 14 is a spinning roller that presses the outer peripheral surface of the pipe material 2 ′ while moving in the direction orthogonal to the axis of the pipe material 2 ′ and the axial direction, and changes the angle with the axis direction of the pipe material 2 ′ to an arbitrary angle. It is possible.
[0025]
As shown in FIG. 9, the cutting means 15 is a cutting tool that presses the outer peripheral surface of the pipe material 2 ′ in the direction orthogonal to the axis.
[0026]
Next, the process of manufacturing a fire extinguisher container using the cylindrical container processing method according to the present invention will be described with reference to FIGS.
[0027]
First, as shown in FIG. 3, the pipe member 2 'is fitted into the core member 18 attached to the drive chuck 12b of the rotational drive means 12 through the opening at one end thereof, and the one end portion of the pipe member 2' is held and fixed by the drive chuck 12b. . In this state, the pressurizing means 13 is driven to approach the rotational drive means 12, and the core member 19 attached to the driven chuck 13b of the pressurizing means 13 is inserted into the other end opening of the pipe member 2 'as shown in FIG. At the same time, the end surface of the driven chuck 13b is brought into contact with the other end of the pipe member 2 ′. In the state of FIG. 4, the opening end of the pipe member 2 ′ is in contact with the end surfaces of the drive chuck 12 b and the driven chuck 13 b, but the protrusion 19 a of the core member 19 has a tip 18 a recess 18 a of the core member 18. It is only inserted in. For this reason, a gap d ₀ is provided between the distal end portion of the core member 18 and the root portion of the convex portion 19 a of the core member 19. In this state, when the movable support 13a is further driven toward the rotational drive means 12, the compressive force can be applied in the axial direction of the pipe material 2 ′.
[0028]
FIG.5 and FIG.6 has shown the diameter reduction thickening process of pipe material 2 '. As shown in FIG. 5, in the state where the pipe member 2 ′ is rotated around its axis by the rotation driving means 12 and the compression force is applied in the axial direction of the pipe material 2 ′ by the pressurizing means 13, the throttle means 14 is moved to the pipe material. By reciprocating in the direction orthogonal to the 2 ′ axis and hitting the central portion of the outer peripheral surface of the pipe material 2 ′, the central portion of the pipe material 2 ′ is recessed and roughened. Next, as shown in FIG. 6, the outer peripheral surface of the pipe member 2 ′ is pressed while the throttle means 14 is reciprocated in the axial direction of the pipe member 2 ′. As a result, as shown in FIG. 7, a reduced diameter thickened portion 2b ′ can be formed at the center of the pipe member 2 ′.
[0029]
In the process of FIG. 5 and FIG. 6, since the central portion of the pipe material 2 ′ expands when the diameter is reduced, the strength of the reduced diameter portion is reduced. Further, the compressive force per unit cross-sectional area acting on the reduced diameter portion of the pipe material 2 ′ is larger than that of the non-processed portion 2a ′. As a result, the reduced diameter portion of the pipe material 2 ′ is compressed in the axial direction, and as shown in FIGS. 4 to 7, the distance between the tip end portion of the core member 18 and the root portion of the convex portion 19a of the core member 19 is reduced. It gradually narrows in the order of d ₀ → d ₁ → d ₂ → d ₃ . 5 and 6, the compressed meat of the pipe material 2 ′ is dispersed within the range of the reduced diameter portion of the pipe material 2 ′. As a result, the reduced diameter portion becomes a reduced diameter thickened portion 2b ′ having a thickness larger than that of the non-processed portion 2a ′ of the pipe material 2 ′ as shown in FIG. The central portion of the reduced diameter thickened portion 2b ′ is the thickest, and gradually becomes thinner as it approaches the non-processed portion 2a ′. This is because the compressive force acts most in the axial direction of the pipe material 2 ′ at the central portion of the reduced diameter thickened portion 2b ′. Further, the thickness of the reduced diameter thickening portion 2b ′ can be appropriately set by changing the compression length (d ₀ −d ₃ ) of the pipe material 2 ′, and the compression length can be set even if the pipe material 2 ′ is thin. By increasing the length, the reduced diameter thickened portion 2b ′ can be formed thick.
[0030]
In the process of FIG. 6, the pressing force may be appropriately changed depending on the moving direction and position of the throttle means 14. For example, when the squeezing means 14 moves from the outside of the pipe material 2 ′ toward the center, the pipe material 2 ′ is pressed strongly, and when it moves from the center of the pipe material 2 ′ to the outside, it is pressed weakly. Thus, thickening of the central portion of the reduced-diameter thickened portion 2b ′ can be promoted, and an excessive thickness of the central portion of the reduced-diameter thickened portion 2b ′ can be dispersed by the reverse operation. As a result, the outer shape of the reduced diameter thickened portion 2b ′ of the pipe material 2 ′ can be formed into the desired shape. Since the inner shape of the pipe member 2 ′ is determined by the shapes of the

core members

18 and 19, the outer diameter of the reduced-diameter and thickened portion 2b ′ of the pipe member 2 ′ is formed into the desired shape, thereby reducing the diameter. The thickened portion 2b ′ can be formed to the desired thickness.
[0031]
Further, at the stage where the diameter-reducing and thickening process of FIG. 7 is completed, a gap d ₃ (for example, about several mm) is opened between the tip end portion of the core member 18 and the root portion of the convex portion 19a of the core member 19. By setting, the compression force can be continuously applied to the pipe material 2 ′ until the diameter-reducing and thickening step is completed. In addition, you may make it eliminate the space | interval between the front-end | tip part of the core member 18, and the root part of the convex part 19a of the core member 19 at the time of completion | finish of a diameter reduction thickening process.
[0032]
8 and 9 show the cutting process of the pipe material 2 '. In a state where the rotation of the pipe material 2 ′ is stopped, as shown in FIG. 8, the movable column 13a is separated from the fixed column 12a, and between the tip of the core member 18 and the root portion of the convex portion 19a of the core member 19 The interval d ₄ is opened. This interval d ₄ is ½ or more of the length of the reduced diameter thickened portion 2b ′. Thereby, the hollow part 20 can be provided in the center part of the reduced diameter thickening part 2b '. Then, as shown in FIG. 9, in a state where the pipe material 2 ′ is rotated by the rotation driving means 12, the cutting means 15 is brought into contact with the central portion of the reduced diameter thickening portion 2b ′ of the pipe material 2 ′ to bring the pipe material 2 into contact. Disconnect '.
[0033]
Through the above steps, two container bodies 2 can be formed simultaneously. And each container main body 2 is removed from the processing apparatus 11, the process which joins the baseplate 3 to the opening edge part by the side of the cylindrical trunk | drum 2a by circumference welding as shown in FIG. 1, and a male screw to the outer peripheral part of the nozzle | cap | die part 2b. The fire extinguisher container 1 is completed through the process of forming the end of the base part 2b, that is, the process of polishing and chamfering the cut surface of the pipe member 2 '.
[0034]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, the rotation driving means 12 is fixed on the base 17. However, the rotation drive unit 12 may be a linear motion element similar to the pressurization unit 13. In this case, the rotation driving means 12 is also a component of the pressurizing means, and the compressive force can be applied symmetrically to the pipe material 2 ′. Thereby, the shape error of the two container main bodies 2 processed simultaneously can be reduced.
[0035]
Moreover, in the said embodiment, although the drive mechanism is not provided in the driven chuck 13b of the pressurization means 13, you may provide the holding mechanism and drive mechanism of pipe material 2 'in the driven chuck 13b. In this case, even after the pipe material 2 'is cut and divided into two container bodies 2, each container body 2 is held and fixed by the drive chuck 12b and the driven chuck 13b and rotated around its axis. Can do. Thereby, the chamfering process of the cut surface of the container main body 2 can be performed after the cutting process of the pipe material 2 ′.
[0036]
Further, in the above embodiment, after cutting the pipe material 2 ′, the cap portion 2b is threaded, but as shown in FIG. 10, before the pipe material 2 ′ is cut, the reduced diameter thickening portion 2b ′. You may perform a threading process. In the threading process, the pipe member 2 ′ is rotated by the rotation driving unit 12, and the thread cutting unit 16 is pressed against the pipe member 2 ′ while pressing the outer peripheral surface of the reduced diameter thickening portion 2 b ′ with the threading unit 16. By moving in the 2 ′ axial direction, a male screw is formed in the reduced diameter thickened portion 2b ′. As shown in FIG. 10, the thread cutting means 16 is a thread cutting tool that presses the outer peripheral surface of the pipe material 2 ′ in the direction orthogonal to the axis. In this case, it is not necessary to form a male screw at the central portion of the reduced diameter thickened portion 2b ′ cut in the cutting step.
[0037]
In the above-described embodiment, the

core members

18 and 19 are described as being formed in a shape corresponding to the shape of the inner surface of the container body 2. However, the

core members

18 and 19 are at least the cylindrical body portion of the container body 2. What is necessary is just to correspond to the inner surface shape of the part from the upper end of 2a to the base part 2b, that is, the part subjected to the reduced diameter thickening process, and the shape of the part corresponding to the cylindrical body 2a of the container body 2 May be smaller than the inner diameter of the cylindrical body 2a.
[0038]
In the above embodiment, the

core members

18 and 19 having different shapes have been described. However, they may have the same shape. In this case, by configuring the

core members

18 and 19 so as to be able to advance and retract in the axial direction of the pipe material 2 ′, the hollow portion 20 is formed at the center of the reduced diameter thickening portion 2b ′ when the pipe material 2 ′ is cut. Can be formed.
[0039]
In the present embodiment, the fire extinguisher container has been described as the cylindrical pressure container. However, as the cylindrical pressure container, there is a gas cylinder in which compressed gas is sealed.
[0040]
【The invention's effect】
Since the processing method of the present invention is integrally formed without welding from the lower end portion of the cylindrical body portion of the container body to the base portion as described above, the cylindrical shape made of steel is formed only by circumferential welding of the container body and the bottom plate. A pressure vessel can be manufactured. That is, since the number of welding locations is reduced as compared with the conventional manufacturing method, pressure leakage due to poor welding of the cylindrical pressure vessel can be reduced, and the aesthetics can be improved.
[0041]
Since the steel pipe was rotated around its axis, and the outer peripheral surface of the pipe was moved in the axial direction while pressing the outer peripheral surface of the pipe with the squeezing means while applying a compressive force to the pipe. A reduced diameter thickening portion can be formed in a part of the pipe material. As a result, it is possible to form a container body of a cylindrical pressure vessel in which the non-processed portion of the pipe material is a cylindrical body portion and the diameter-reduced and thickened portion is a base portion. Since it is thicker than the processed portion, the cylindrical body can be formed thin while ensuring the effective thickness of the base of the container body. Thus, since the container main body which occupies most cylindrical pressure vessels can be reduced in weight, a lightweight cylindrical pressure vessel can be provided.
[0042]
In addition, since a predetermined portion of the pipe material is reduced in diameter and pressed against the shape portion of the core member to form a reduced diameter thickened portion that becomes a die portion, the reduced diameter thickened portion, and thus the die portion, is expected. The two container bodies can be formed simultaneously by cutting the pipe material at the reduced diameter thickening portion.
[0043]
Two sets of core members are provided with a concave portion and a convex portion at opposing tip portions, and the convex portion of one core member is movably fitted into the concave portion of the other core member. The coaxiality of the set of core members can be ensured, and the processing accuracy can be increased. Further, the pressing force by the squeezing means moves when the squeezing means moves from the outer portion of the predetermined portion of the pipe material toward the central portion, and when the squeezing means moves from the central portion of the predetermined portion of the pipe material toward the outer portion. By changing according to the time, the accuracy of the shape and thickness of the reduced diameter thickening portion and by extension the base portion can be increased.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view illustrating a fire extinguisher container manufactured using a processing method according to the present invention.
FIG. 2 is a schematic view illustrating a processing apparatus using the processing method according to the present invention.
FIG. 3 is a schematic diagram showing a process of attaching a pipe material to a rotation driving means.
FIG. 4 is a schematic view showing a state in which a pipe material is attached to a rotation driving means.
FIG. 5 is a schematic view showing rough processing in a diameter-reducing thickening process of a pipe material.
FIG. 6 is a schematic view showing a finishing process in a pipe material reduced diameter thickening step.
FIG. 7 is a longitudinal sectional view showing a reduced diameter thickening portion of a pipe material.
FIG. 8 is a schematic diagram showing a threading process of a pipe material.
FIG. 9 is a schematic view showing a pipe material cutting step.
FIG. 10 is a schematic view showing a pipe material cutting step.
FIG. 11 is a longitudinal sectional view illustrating a conventional fire extinguisher container.
12A is a schematic view illustrating a processing method of the fire extinguisher container of FIG. 11, and FIGS. 12B and 12C are schematic views illustrating other processing methods.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fire extinguisher container 2 Container main body 2a Cylindrical trunk | drum 2b Base part 2 'Pipe material 2b' Reduced diameter thickening part 3 Bottom plate 11 Processing apparatus 12 Rotation drive means 12b Drive chuck 13 Pressurization means 13b Follower chuck 14 Restriction means 15 Cutting means 18, 19 Core member

Claims

A processing method of a steel cylindrical pressure vessel formed by joining two members, a container body integrally formed from the lower end portion of the cylindrical body portion to the base portion, and a bottom plate closing the lower end opening of the container body. Because
The steel pipe material is chucked by the chuck at one end of the rotary shaft of the spatula drawing machine, and has a shape portion corresponding to the inner surface shape of the mouthpiece portion in a state where the mouthpiece portions of the two container bodies are abutted with each other. A set of two core members are fitted to the inner diameter of the pipe material in an opposed state, and the opposite end portions of the set of two core members are respectively provided with a concave portion and a convex portion, In a state where the convex portion of the core member is movably fitted in the concave portion of the other core member, the pipe member is rotated around its axis, and a compressive force is applied to the pipe member in the axial direction. The predetermined diameter of the pipe material is reduced and the core member is reduced in diameter by reciprocating in the axial direction while pressing the outer peripheral surface of the predetermined area of the pipe material corresponding to the shape portion of the core member with a squeezing means. Of the above It is pressed against the Jo portion, the cylindrical pressure vessel method machining and forming a reduced 径肥 thickening unit to be the mouthpiece.

When the pressing means moves from the outer part of the predetermined part of the pipe material toward the central part, the pressing means moves from the central part of the predetermined part of the pipe material to the outer part. The method for processing a cylindrical pressure vessel according to claim 1 , wherein the processing method varies depending on when the cylinder is moved.