JP2004106030A - Method and apparatus for manufacturing special shaped tube stock for hydraulic bulging - Google Patents

Method and apparatus for manufacturing special shaped tube stock for hydraulic bulging Download PDF

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JP2004106030A
JP2004106030A JP2002273762A JP2002273762A JP2004106030A JP 2004106030 A JP2004106030 A JP 2004106030A JP 2002273762 A JP2002273762 A JP 2002273762A JP 2002273762 A JP2002273762 A JP 2002273762A JP 2004106030 A JP2004106030 A JP 2004106030A
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Prior art keywords
welding
bending
hydraulic bulging
deformed pipe
pipe
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JP2002273762A
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JP3925370B2 (en
Inventor
Masanori Taiyama
泰山 正則
Atsushi Tomizawa
富澤 淳
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Sumitomo Metal Ind Ltd
住友金属工業株式会社
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Abstract

<P>PROBLEM TO BE SOLVED: To make the efficient production of taper tubes possible and to manufacture products having excellent quality in which weld defects are less than those in conventional products. <P>SOLUTION: Butting parts are welded in the state where a metallic sheet 23b is set to an O-bending die 25b after performing the final bending of the metallic sheet with a manufacturing apparatus for taper tubes, the circumference of which is arbitrarily changeable in the axial direction for hydraulic bulging which is provided with a forming device by bending and a welding device. By this invention, the securement of high accuracy of a welded joint is enabled and the quality of a product is improved. Moreover, an off-line welding machine is not required, so exclusive equipment and personnel required for welding are unnecessary and a lead time is shortened, so that the efficient production is enabled. <P>COPYRIGHT: (C)2004,JPO

Description

【0001】
【発明の属する技術分野】
本発明は、液圧バルジ加工を施す対象となる例えばテーパ管を製造する方法及び装置に関するものである。
【0002】
【従来の技術】
液圧バルジ加工は、通常の成形法に比べて以下の特長がある。
▲1▼ 長手方向に断面形状の異なるやや複雑な形状を得ることができるため、従来は溶接で組み付けていた部品の一体成形が可能になる。
【0003】
▲2▼ 製品の全体に亘って加工硬化を得やすいため、軟質な素管を使用した場合であっても高強度な製品を得ることができる。
▲3▼ スプリングバックが少なく、寸法精度が良好な製品を得ることができる(形状凍結性が良好である)ため、手直しの工程を省略できる。
【0004】
以上のような優れた特長が評価され、近年、管の液圧バルジ加工は、特に自動車部品を始めとして種々の分野で盛んに採用されるようになってきた。
一般的には、素材となるほぼ長手方向に均一な円断面を有するストレートな管(以下、「素管」という。)に対し、(1)曲げ加工、(2)押し潰し加工、(3)液圧バルジ加工、の一連の加工を施すことによって製品を製造するものである。
【0005】
そして、最終工程である液圧バルジ加工では、金型内にセットした曲げ加工・押し潰し加工後の素管の中に加工液を注入し、その圧力(以下、「内圧」という。)を高めることに加えて、管端から軸押し力を付加することにより、種々の断面形状を有する製品に加工する。
【0006】
しかしながら、このような液圧バルジ加工においても以下に述べるような問題がある。
すなわち、軸方向に断面形状の異なるやや複雑な形状を得ることができるといっても、それには限界がある。周長増加率={(当該部位の外周長/素管の円周長)−1}×100%と定義すれば、製品の形状要求性能や素管の材質・板厚にもよるが、管端の軸圧縮が有効な管端部領域を除いて、限界周長増加率を25%以下に設定するのが一般的である。つまり、製品の形状設計の自由度を上げ、より複雑な任意の断面形状を有する製品を得ようとするためには、更なる工夫が必要である。
【0007】
この問題に対しては、ストレートな素管に代えて略円錐状の素管(以下、「テーパ管」という。)を用いることで、ストレートな素管での成形が困難な部品、例えば自動車部品で軸方向に沿って大きく周長が変化する部品(周長増加率100%以上)に対しても周長増加率を低く抑えることができるため、成形が可能になる(例えば特許文献1参照。)。
【0008】
【特許文献1】
特開2001−321842号公報(第1頁)
【0009】
ところで、上記方法に使用するテーパ管を製造するに際しては、スエージングマシーンを使用する方法や、UOプレスによる方法等が知られているが、何れの方法も、通常のストレートな溶接管を製造する工程に比べて製造工程が複雑であることから、効率的な生産が困難である。更に、UOプレスによる方法では、3次元的に複雑な形状のテーパ管の溶接工程でのセッティングが困難で、健全な溶接部を得るための継手精度を確保するために多大な工数を必要としていた。
【0010】
以下、従来のUOプレスによるテーパ管の製造方法について更に詳細に説明する。
図4及び図5は従来のUO成形による代表的なテーパ管の製造工程を説明した図である。
【0011】
先ず、図4(a)に示すように略台形状に切断された金属板1aを素材として、図4(b)に示すようにプレス機に取付けられたC曲げ用ポンチ2とダイス3によって、金属板1aの端部に曲げ加工(端部のC曲げ工程)を行う。なお、端部のC曲げの曲率は、スプリングバックを考慮して長手方向に変化させている。
【0012】
図4(c)に示すように、両端部をC曲げ加工された金属板1bは、続いて、図4(d)に示すようにU曲げ用ポンチ4とダイス5によってU型に曲げられた後、左右のサイドシリンダ6に取付けたローラ6aにより、両端部に水平方向の圧縮加工を受け、図4(e)に示すようにU形状に加工される(U曲げ工程)。なお、U曲げの曲率も、スプリングバックを考慮して長手方向に変化させている。
【0013】
前記C曲げに続いてU曲げ加工された金属板1cは、図5(a)に示したようにプレス機に取付けられたO曲げ用ダイス7a,7bにセッティングされ、最終的に図5(b)に示すようにO形状に曲げ加工される(O曲げ工程)。
【0014】
O曲げ加工された金属板1dは前記ダイス7a,7bから外され、溶接のため、図5(c)に示したように溶接治具8a,8bに固定され、突合せの隙間を最小にするため、突合せ方向に押力が付与される。この固定された金属板1dの突合せ位置1daは溶接ロボットに教示され、図5(d)に示すように溶接トーチ9により溶接され、テーパ管1eと成される。
なお、上記の方法において、C曲げ工程が省略される場合もある。
【0015】
図6は別のUO成形によるテーパ管の製造工程を説明した図である。
図6に示す方法は、図6(a)に示すようにダイス10に金属板1aを挿入し、ポンチ11によってC曲げ成形を行うが、前記ポンチ11を用いて金属板1aを部分的に複数回にわたってプレスした後に、金属板1aを中央にセッティングし、最終のプレスを行う。その後、O形状に曲げ成形された金属板(1d)は、図6(b)に示す溶接工程に送られ、金属板1dの成形品を軸方向に移動させつつ、回転可能な溶接用サポートロール12で両側から押え付けながら、溶接トーチ9で溶接を行い、テーパ管1eと成される。
【0016】
図7は更に別のUO成形によるテーパ管の製造工程を説明した図である。
図7に示す方法は、図4及び図5に示したUO成形による代表的なテーパ管の製造工程と同様に、先ず、図7(a)に示したようにC曲げ用ポンチ2とダイス3によって、金属板の端部にC曲げ加工を行った後、図7(b)に示すようにU曲げ用ポンチ4とダイス5によってU形状に成形する。
【0017】
次に、溶接工程に送り、図7(c)に示すように、金属板1dの成形品を軸方向に移動させながら、回転可能な溶接用サポートロール12で両側から押え付けて溶接トーチ9で溶接を行い、テーパ管1eと成す。
【0018】
【発明が解決しようとする課題】
以上説明した従来方法において、健全な溶接部を得るためには、継手の精度(突合せ継手の隙間及び溶接狙い位置の精度)を確保することが肝要であるが、成形された金属板の継手部では、スプリングバックを生じるために突合せ隙間が発生する。従って、この突合せ溶接継手の隙間を極小とするため、溶接前のテーパ管を固定した後、溶接部となる突合せ端面を押し合わせる工程が必要であった。
【0019】
更に、固定した溶接前テーパ管の突合せ継手の突合せ位置を正確に倣って溶接する必要があるが、3次元的に複雑な形状のテーパ管では、溶接工程でのセッティングによる位置ばらつきや、前述の押し合わせ工程による突合せ位置のずれのため、溶接体毎に突合せ位置を溶接狙い位置として教示・修正する必要があった。
【0020】
また、オフラインの溶接機で溶接を行うため、専用の設備と作業要員が必要であり、更に、リードタイムが長くなるという問題もあった。
【0021】
本発明は、上記した従来の問題点に鑑みてなされたものであり、テーパ管等のように横断面形状が軸方向に変化する異径鋼管の効率的な生産を可能とすると共に、従来以上に溶接欠陥の少ない品質良好な製品の製造を可能とすること、具体的には、溶接工程での継手精度(突合せ隙間と溶接狙い位置の精度)を向上させることにより、製品品質を向上させ、さらに製造工程を簡略化することを目的とする液圧バルジ加工用異形素管の製造方法及び装置を提供することを目的としている。
【0022】
【課題を解決するための手段】
上記した目的を達成するために、本発明は、最終曲げ成形の終了後、下金型に材料がセッティングされた状態にて、突合せ位置を溶接することとしている。
【0023】
そして、このような本発明によれば、溶接工程での継手精度(突合せ隙間と溶接狙い位置の精度)が向上して製品品質が向上し、さらに製造工程を簡略化できるようになる。
【0024】
【発明の実施の形態】
本発明に係る液圧バルジ加工用異形素管の製造方法は、軸方向に周長が任意に変化する液圧バルジ加工用異形素管を製造する方法において、最終曲げ成形の終了後、下金型に材料がセッティングされた状態にて、突合せ位置を溶接するものである。
【0025】
上記の本発明に係る液圧バルジ加工用異形素管の製造方法は、最終曲げ成形直後に材料が最終曲げ金型にセッティングされた状態で溶接を行うので、溶接工程での継手精度を向上させることができ、更に、部品製造工程の大幅な簡略化を実現できる。
【0026】
本発明における溶接は、片側から溶接できるものであれば良い。また、溶接工程面からは、使用する溶接法について特に規定する必要はなく、レーザ溶接、TIG溶接、プラズマ溶接等の溶接法を適用することが可能であり、溶接部に必要とされる特性から、溶接法を選定すればよい。
【0027】
上記の本発明において、曲げ成形装置と溶接装置を備えた、軸方向に周長が任意に変化する液圧バルジ加工用異形素管の製造装置における前記溶接装置の上流側に、溶接位置近傍を固持するためのクランプ装置を設けた本発明に係る異形素管の製造装置を使用し、最終曲げ金型の下金型にセッティングした材料の溶接位置近傍をクランプした状態で溶接する場合には、溶接中の熱により発生する歪の影響を排除できる。
【0028】
また、上記の本発明に係る液圧バルジ加工用異形素管の製造装置において、前記溶接装置の上流側に、溶接トーチを突合せ部に追従させるための倣い装置を設け、溶接時、周方向の溶接狙い位置を補正しつつ溶接する場合には、溶接狙い位置の精度の向上が図れ、レーザ溶接のような厳しい狙い位置精度が要求される溶接法を使用する場合でも、更なる溶接品質の向上が可能になる。
【0029】
また、上記の本発明に係る液圧バルジ加工用異形素管の製造装置において、前記溶接装置の下流側に、溶接部の健全性を判定する装置を設け、溶接と共に、溶接部の健全性の判定を行う場合には、溶接完了と同時に溶接部の健全性を判定できるので、液圧バルジ加工前に溶接不良を判別でき、バルジ加工における割れ発生率を低減することができる。
【0030】
【実施例】
以下、本発明に係る液圧バルジ加工用異形素管の製造装置の要部概略を図1〜図3に示す実施例に基づいて説明し、本発明に係る液圧バルジ加工用異形素管の製造方法の説明する。
図1〜図3は本発明に係る液圧バルジ加工用異形素管の製造装置の要部概略説明図である。
【0031】
図1(a)において、21はU曲げ用ポンチ、22はこのU曲げ用ポンチ21と対を成すダイスであり、例えば両端部にC曲げ加工が施された略台形状の金属板をU型に曲げるものである。このU型に曲げられた金属板23aは、左右のサイドシリンダ24に取付けたローラ24aにより、両端部に水平方向の圧縮加工を与えられ、U形状に加工される。
【0032】
このようにU曲げ加工を施された金属板23aは、図1(b)に示したようにプレス機に取付けられたO曲げ用ダイス25a,25bにセットされ、最終的にO形状に曲げ加工される。また、図示はしていないが、O曲げ成形時にスラスト力が発生する場合があるため、テーパ管の端面位置に軸方向の移動を防ぐためのスラスト受け具を設置しても良い。異形管の形状にもよるが、単純なテーパ管の場合には、大径側にスラスト受け具を設置することが有効である。
【0033】
以上の最終曲げ成形までは、従来の製造方法と同様であるが、本発明に係る液圧バルジ加工用異形素管の製造方法では、前記O曲げ加工された金属板23bは、図1(c)(d)に示すように、上方に位置する前記ダイス25aのみが除去され、下方のダイス25bにセッティングしたままで溶接トーチ26により溶接する。
【0034】
このように、本発明に係る液圧バルジ加工用異形素管の製造方法では、最終曲げ成形の終了後、金属板23bを下方のダイス25bにセッティングしたまま、すなわち、金属板23bを下方のダイス25bから開放しないまま溶接するので、従来方法と比べてスプリングバックの影響が小さく、突合せ方向の押し力を付与することなく、突合せの隙間を健全な溶接部が得られる許容範囲に抑制することができる。
【0035】
更に、本発明に係る液圧バルジ加工用異形素管の製造方法では、金属板23bが下方のダイス25bから開放されないため、U,O曲げ工程によって形成される溶接部となる突合せ位置のばらつきが小さくなり、溶接狙い位置の修正工数が大幅に低減できるようになる。
【0036】
つまり、本発明に係る液圧バルジ加工用異形素管の製造方法では、金属板23bを下方のダイス25bから開放せずに溶接することで、高い継手精度の確保と、製造工程の簡略化を図ることを骨子としている。従って、最終曲げ成形を、図2(b)に示したような分割型の金型27aによって行う場合でも、下方の金型27bに固定したままであれば、同様の効果が得られることは言うまでもない。
【0037】
また、前述した従来方法の別の形態である、図6(a)に示したC曲げを複数回実施した後で溶接を行う場合でも、下方に設置したダイス10に金属板をセッティングしたまま溶接工程を実施すれば、同様の効果が得られる。同様に、図7(a)に示す端部のC曲げ成形を行った後、U曲げ成形を行って最終の溶接前の形状を得る場合でも、図7(b)に示すダイス5に金属板をセッティングしたまま、溶接工程を実施すれば同様の効果が得られる。
【0038】
ところで、板厚等によっては、溶接時の熱歪が懸念される場合がある。軽微な場合には、溶接トーチ26により溶接開始端・終端の何れか一方或いは両方を仮付け溶接することによっても健全な溶接部が得られるが、大きな熱歪が懸念される場合には、前記熱歪を考慮して突合せ部の目違い、口開きを抑制するためのクランプ装置を、図3に示したように、例えば溶接トーチ26の上流側近傍に配置し、溶接位置近傍をクランプした状態で溶接することで、より寸法精度の優れたテーパ管を得ることができるようになる。
【0039】
クランプ装置としては、図3(a)(b)に示すようなローラ式の押さえ治具28や、図3(c)(d)に示すような押さえ型29を用いたものなどが採用される。
【0040】
また、図3に示した実施例では、溶接トーチ26の上流側の前記クランプ装置との間に突合せ部に追従する倣い装置30を設置し、溶接狙い位置の精度を向上させるものが開示されている。このような倣い装置30を付加し、溶接時には、溶接トーチ26を突合せ部に追従させた場合には、レーザ溶接のような厳しい狙い位置精度が要求される溶接法でも更なる溶接品質の向上が可能になる。
【0041】
これらの倣い装置30では、視野範囲が狭いため、従来の技術では、溶接工程にて溶接トーチ位置を修正する、或いは、溶接ワークの突合せ溶接位置を修正(ワークをセッティングし直す)する必要があったが、本発明においては、突合せ位置の繰り返し精度が向上されるため、上記位置修正の工程を省略することができる。なお、倣い装置30は、従来から用いられているレーザ反射光により突合せ位置を検出するタイプのもの等を使用すれば良い。
【0042】
更に、図3に示した実施例では、溶接トーチ26の下流側に溶接部の健全性を判定する装置31を設置し、この判定装置31により溶接と共に溶接部の健全性の判定を行うものを示している。このように、判定装置31によって溶接と共に溶接部の健全性の判定を行った場合には、液圧バルジ加工を行う前に溶接不良か否かを判別できるので、バルジ加工における割れ発生率を低減することができるようになる。なお、この判定装置は、従来から使用されているレーザ変位計による溶接ビード表面のプロフィールを判定するもの等を使用すれば良い。
【0043】
本発明は、テーパ管のような横断面形状が軸方向に変化する異径鋼管を製造するに際し、材料を成形での最終工程で使用した下金型に固定したままの状態で溶接工程を行うことを特徴とするものであり、C曲げ、U曲げ、O曲げの工程順序に限定されるものではない。
【0044】
また、管端部或いは全長における断面の矩形化や製品形状に近い形状に加工することも本発明の趣旨とするところであり、図1〜図3に示した実施例では、長手方向に単調に周長が増加するテーパ管を製造する場合についてのみ説明したが、長手方向に任意に周長が変化する異形管を製造するものであっても良い。もちろん、素材となる金属板の形状は、正確にはテーパ管の展開形状に合わせた曲線形状とすればよいが、直線で近似した台形や多角形でもよいのである。今回は、素材となる金属板を単一の金属板としたが、異種材の接合板、或いは、板厚の異なる接合板でもよい。接合の方法としては、テーラードブランクやクラッドなどが適用できる。
【0045】
また、図2,3では溶接トーチ26を突合せ部に沿って移動させるものを示したが、下金型ごと材料を移動させて溶接するものでも良い。
【0046】
【発明の効果】
以上説明したように、本発明によれば、例えばテーパ管のように軸方向に横断面形状が変化する異形鋼管の製造に際し、O曲げ成形直後に材料が下O曲げ金型にセッティングされた状態で溶接するので、高い溶接継手精度を確保することが可能になり、製品品質の向上が図れるようになる。
【0047】
また、本発明では、オフラインの溶接機を必要としないので、溶接専用の設備と作業要員が不必要になり、更にリードタイムを短くすることができ、効率的な生産が可能になる。勿論、従来以上に複雑な形状を有する製品を、成形不良なく、良好な品質で液圧バルジ加工できるようになる。
【図面の簡単な説明】
【図1】本発明に係る液圧バルジ加工用異形素管の製造装置の要部概略説明図であり、(a)はU曲げ装置の縦断面図、(b)はO曲げ装置の縦断面図、(c)は溶接装置の斜視図、(d)は(c)を側面から見た図である。
【図2】本発明に係る液圧バルジ加工用異形素管の製造装置の他の態様を示す要部概略説明図であり、(a)はU曲げ装置の縦断面図、(b)は最終成形であるU曲げ装置の縦断面図である。
【図3】本発明に係る液圧バルジ加工用異形素管の製造装置の更に他の態様を示す要部概略説明図であり、(a)はローラによりクランプする場合のクランプ装置の縦断面図、(b)は(a)を側面から見た図、(c)は押え型によるクランプする場合のクランプ装置の縦断面図、(d)は(c)を側面から見た図である。
【図4】従来の液圧バルジ加工用異形素管の製造工程の説明図で、(a)は素材を示す斜視図、(b)は端部のC曲げ工程の説明図、(c)は両端部をC曲げ加工した素材の斜視図、(d)はU曲げ工程の説明図、(e)はU曲げ加工した素材の斜視図である。
【図5】従来の液圧バルジ加工用異形素管の製造工程の説明図で、(a)はO曲げ工程の説明図、(b)はO曲げ加工した素材の斜視図、(c)は溶接工程の説明図、(d)は溶接加工する素材の斜視図である。
【図6】別の従来の液圧バルジ加工用異形素管の製造工程の説明図で、(a)は端部のC曲げ工程の説明図、(b)は溶接工程の説明図である。
【図7】更に別の従来の液圧バルジ加工用異形素管の製造工程の説明図で、(a)は端部のC曲げ工程の説明図、(b)はU曲げ工程の説明図、(c)は溶接工程の説明図である。
【符号の説明】
25a  O曲げ用ダイス
25b  O曲げ用ダイス
26   溶接トーチ
27a  O曲げ用金型
27b  O曲げ用金型
28   ローラ式押さえ治具
29   押さえ型
30   倣い装置
31   判定装置
[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for manufacturing, for example, a tapered pipe to be subjected to hydraulic bulging.
[0002]
[Prior art]
Hydraulic bulging has the following features as compared with the normal molding method.
{Circle around (1)} Since it is possible to obtain a slightly complicated shape having a different cross-sectional shape in the longitudinal direction, it is possible to integrally mold parts that have been conventionally assembled by welding.
[0003]
{Circle around (2)} Since work hardening is easily obtained over the entire product, a high-strength product can be obtained even when a soft raw tube is used.
{Circle around (3)} Since a product with little springback and good dimensional accuracy can be obtained (good shape freezing property), a reworking step can be omitted.
[0004]
These excellent features have been evaluated, and in recent years, hydraulic bulging of pipes has been actively adopted in various fields, particularly in automobile parts.
Generally, a straight pipe (hereinafter, referred to as a "base pipe") having a substantially uniform circular cross section in a longitudinal direction as a material is (1) bent, (2) crushed, and (3). The product is manufactured by performing a series of hydraulic bulging processes.
[0005]
In the final step of hydraulic bulging, a working fluid is poured into the tube after bending and crushing set in the mold, and the pressure (hereinafter referred to as “internal pressure”) is increased. In addition, by applying an axial pushing force from the pipe end, the product is processed into products having various cross-sectional shapes.
[0006]
However, such hydraulic bulging also has the following problems.
That is, even if it is possible to obtain a slightly complicated shape having a different cross-sectional shape in the axial direction, there is a limit to this. If defined as perimeter increase rate = {(peripheral length of pertinent portion / circumferential length of tube) -1} x 100%, depending on the required shape of the product and the material and plate thickness of the tube, Except for the tube end region where the axial compression at the end is effective, it is general to set the critical circumference increase rate to 25% or less. That is, in order to increase the degree of freedom in designing the shape of the product and to obtain a product having a more complicated arbitrary cross-sectional shape, further measures are required.
[0007]
To solve this problem, by using a substantially conical base tube (hereinafter referred to as a "tapered tube") instead of a straight base tube, a part which is difficult to form with a straight base tube, for example, an automobile part Therefore, even for a component whose circumference changes greatly along the axial direction (a circumference increase rate of 100% or more), the circumference increase rate can be suppressed to be low, so that molding is possible (for example, see Patent Document 1). ).
[0008]
[Patent Document 1]
JP 2001-321842 A (page 1)
[0009]
By the way, in manufacturing the tapered pipe used in the above method, a method using a swaging machine, a method using a UO press, and the like are known, and any of the methods manufactures a normal straight welded pipe. Since the manufacturing process is more complicated than the process, efficient production is difficult. Further, in the method using a UO press, it is difficult to set a tapered pipe having a three-dimensionally complicated shape in a welding process, and a large number of man-hours are required to secure joint accuracy for obtaining a sound weld. .
[0010]
Hereinafter, a conventional method of manufacturing a tapered tube by a UO press will be described in more detail.
FIG. 4 and FIG. 5 are views for explaining a process of manufacturing a typical tapered tube by conventional UO molding.
[0011]
First, as shown in FIG. 4 (a), using a metal plate 1a cut into a substantially trapezoidal shape as a raw material, a C-bending punch 2 and a die 3 attached to a press machine as shown in FIG. A bending process (C bending process of the end portion) is performed on the end portion of the metal plate 1a. The curvature of the C-bend at the end is changed in the longitudinal direction in consideration of springback.
[0012]
As shown in FIG. 4 (c), the metal plate 1b whose both ends are C-curved is subsequently bent into a U-shape by the U-bending punch 4 and the die 5 as shown in FIG. 4 (d). Thereafter, both ends are subjected to horizontal compression processing by rollers 6a attached to the left and right side cylinders 6 to be processed into a U shape as shown in FIG. 4 (e) (U bending step). The curvature of the U-bending is also changed in the longitudinal direction in consideration of springback.
[0013]
The metal plate 1c that has been U-bent following the C-bending is set on the O-bending dies 7a and 7b attached to the press machine as shown in FIG. ), The sheet is bent into an O shape (O bending step).
[0014]
The O-bent metal plate 1d is removed from the dies 7a and 7b and fixed to welding jigs 8a and 8b for welding as shown in FIG. , A pressing force is applied in the butting direction. The butted position 1da of the fixed metal plate 1d is taught to the welding robot, and is welded by the welding torch 9 as shown in FIG. 5D to form a tapered tube 1e.
In the above method, the C bending step may be omitted.
[0015]
FIG. 6 is a view for explaining another tapered tube manufacturing process by UO molding.
In the method shown in FIG. 6, as shown in FIG. 6A, the metal plate 1 a is inserted into the die 10 and C-bending is performed by the punch 11. After pressing several times, the metal plate 1a is set at the center, and final pressing is performed. Thereafter, the metal plate (1d) bent and formed into an O shape is sent to the welding process shown in FIG. 6B, and the rotatable support roll for welding is moved while moving the formed product of the metal plate 1d in the axial direction. Welding is performed with the welding torch 9 while pressing from both sides at 12 to form a tapered tube 1e.
[0016]
FIG. 7 is a view illustrating a process of manufacturing a tapered tube by another UO molding.
The method shown in FIG. 7 is similar to the typical tapered tube manufacturing process by UO molding shown in FIGS. 4 and 5, and first, as shown in FIG. After the C-bending process is performed on the end of the metal plate, the metal plate is formed into a U-shape by a U-bending punch 4 and a die 5 as shown in FIG.
[0017]
Next, it is sent to a welding process, and as shown in FIG. 7 (c), while the molded product of the metal plate 1d is moved in the axial direction, it is pressed from both sides by a rotatable support roll 12 for welding, and the welding torch 9 Weld to form a tapered tube 1e.
[0018]
[Problems to be solved by the invention]
In the conventional method described above, in order to obtain a sound welded portion, it is important to ensure the accuracy of the joint (the accuracy of the gap between the butt joints and the accuracy of the welding target position). In this case, a butting gap is generated due to springback. Therefore, in order to minimize the gap between the butt-welded joints, it is necessary to fix the tapered pipe before welding, and then press a butt end face to be a welded portion.
[0019]
Further, it is necessary to accurately weld the butt joint of the butt joint of the fixed tapered pipe before welding, but in the case of a tapered pipe having a three-dimensionally complicated shape, positional variations due to the setting in the welding process, and the aforementioned Because of the displacement of the butting position due to the pressing process, it was necessary to teach and correct the butting position as the welding target position for each welded body.
[0020]
In addition, since welding is performed by an off-line welding machine, dedicated equipment and operation personnel are required, and further, there is a problem that a lead time is lengthened.
[0021]
The present invention has been made in view of the above-described conventional problems, and enables efficient production of different-diameter steel pipes whose cross-sectional shape changes in the axial direction, such as a tapered pipe, and more than before. It is possible to improve the quality of products by improving the joint accuracy in the welding process (the accuracy of the butt gap and the welding target position) by enabling the production of good quality products with few welding defects. It is another object of the present invention to provide a method and an apparatus for manufacturing a deformed pipe for hydraulic bulging, which aims at simplifying the manufacturing process.
[0022]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, according to the present invention, after the final bending, the butt position is welded in a state where the material is set in the lower mold.
[0023]
According to the present invention, the joint accuracy in the welding process (the accuracy of the butt gap and the welding target position) is improved, the product quality is improved, and the manufacturing process can be further simplified.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
The method for manufacturing a deformed pipe for hydraulic bulging according to the present invention is a method for manufacturing a deformed pipe for hydraulic bulging in which the circumferential length changes arbitrarily in the axial direction. With the material set in the mold, the butting position is welded.
[0025]
In the method of manufacturing the deformed pipe for hydraulic bulging according to the above-described present invention, welding is performed in a state where the material is set in the final bending mold immediately after the final bending, so that the joint accuracy in the welding process is improved. In addition, the component manufacturing process can be greatly simplified.
[0026]
The welding in the present invention may be any welding that can be performed from one side. From the welding process side, it is not necessary to particularly define the welding method to be used, and welding methods such as laser welding, TIG welding, and plasma welding can be applied. The welding method may be selected.
[0027]
In the present invention, the bending device and the welding device are provided, and the peripheral length is arbitrarily changed in the axial direction. When using the deformed pipe manufacturing apparatus according to the present invention provided with a clamping device for holding, when welding in a state where the vicinity of the welding position of the material set in the lower die of the final bending die is clamped, The effect of distortion generated by heat during welding can be eliminated.
[0028]
In the apparatus for manufacturing a deformed pipe for hydraulic bulging according to the present invention, a copying apparatus is provided on the upstream side of the welding apparatus for causing a welding torch to follow a butt portion. When welding while correcting the welding target position, the accuracy of the welding target position can be improved, and even when using a welding method that requires strict target position accuracy, such as laser welding, further improvement in welding quality Becomes possible.
[0029]
In the apparatus for manufacturing a deformed pipe for hydraulic bulging according to the present invention, a device for determining the soundness of the welded portion is provided downstream of the welding device. When performing the determination, the soundness of the welded portion can be determined at the same time as the completion of the welding, so that the welding failure can be determined before the hydraulic bulging, and the crack occurrence rate in the bulging can be reduced.
[0030]
【Example】
Hereinafter, an outline of a main part of an apparatus for manufacturing a deformed pipe for hydraulic bulging according to the present invention will be described based on an embodiment shown in FIGS. The manufacturing method will be described.
1 to 3 are schematic illustrations of a main part of an apparatus for manufacturing a deformed pipe for hydraulic bulging according to the present invention.
[0031]
In FIG. 1A, reference numeral 21 denotes a U-bending punch, and reference numeral 22 denotes a die forming a pair with the U-bending punch 21. For example, a substantially trapezoidal metal plate having a C-bend at both ends is formed into a U-shape. It is bent. The metal plate 23a bent into a U shape is subjected to horizontal compression at both ends by rollers 24a attached to the left and right side cylinders 24, and is processed into a U shape.
[0032]
The metal plate 23a thus subjected to the U-bending is set on the O-bending dies 25a and 25b attached to the press as shown in FIG. 1B, and finally bent into the O-shape. Is done. Although not shown, a thrust force may be generated at the time of O-bending forming. Therefore, a thrust receiver for preventing axial movement may be provided at the end face position of the tapered pipe. Although it depends on the shape of the deformed pipe, in the case of a simple tapered pipe, it is effective to install a thrust receiver on the large diameter side.
[0033]
Up to the final bending, the manufacturing method is the same as the conventional manufacturing method. However, in the method for manufacturing the deformed pipe for hydraulic bulging according to the present invention, the O-bent metal plate 23b is formed as shown in FIG. (D) As shown in (d), only the die 25a located above is removed, and welding is performed with the welding torch 26 while setting the die 25b below.
[0034]
As described above, in the method of manufacturing the deformed pipe for hydraulic bulging according to the present invention, after the final bending, the metal plate 23b is set to the lower die 25b, that is, the metal plate 23b is moved to the lower die. Since the welding is performed without opening from 25b, the influence of springback is smaller than that of the conventional method, and the gap of the butt can be suppressed to an allowable range where a healthy weld can be obtained without applying a pushing force in the butt direction. it can.
[0035]
Further, in the method of manufacturing the deformed pipe for hydraulic bulging according to the present invention, since the metal plate 23b is not released from the lower die 25b, the variation in the butt position serving as the welded portion formed by the U and O bending processes is reduced. Therefore, the man-hour for correcting the welding target position can be greatly reduced.
[0036]
That is, in the method of manufacturing the deformed pipe for hydraulic bulging according to the present invention, the metal plate 23b is welded without being opened from the lower die 25b, thereby ensuring high joint accuracy and simplifying the manufacturing process. The idea is to plan. Therefore, even when the final bending is performed using the split mold 27a as shown in FIG. 2B, it goes without saying that the same effect can be obtained as long as it is fixed to the lower mold 27b. No.
[0037]
Further, even in the case where welding is performed after performing the C-bending shown in FIG. 6A a plurality of times, which is another form of the above-described conventional method, the welding is performed while the metal plate is set on the die 10 installed below. The same effect can be obtained by performing the steps. Similarly, even when the end portion shown in FIG. 7A is subjected to the C-bend forming and then the U-bend forming is performed to obtain the final shape before welding, the metal plate is attached to the die 5 shown in FIG. 7B. The same effect can be obtained by performing the welding process while setting.
[0038]
By the way, depending on the plate thickness or the like, there is a case where thermal distortion at the time of welding is concerned. In a slight case, a sound weld can be obtained by tack welding one or both of the welding start end and the terminal end with the welding torch 26. As shown in FIG. 3, a clamp device for suppressing misalignment of the butt portions and opening of the mouth in consideration of thermal strain is disposed, for example, in the vicinity of the upstream side of the welding torch 26 and the vicinity of the welding position is clamped. By welding in the manner described above, it becomes possible to obtain a tapered pipe having more excellent dimensional accuracy.
[0039]
As the clamp device, a roller type holding jig 28 as shown in FIGS. 3A and 3B or a device using a holding mold 29 as shown in FIGS. 3C and 3D is adopted. .
[0040]
Further, in the embodiment shown in FIG. 3, there is disclosed a configuration in which a copying apparatus 30 that follows a butt portion is installed between the clamping apparatus on the upstream side of the welding torch 26 and improves the accuracy of a welding target position. I have. If such a copying apparatus 30 is added and the welding torch 26 is made to follow the butt portion during welding, further improvement in welding quality can be achieved even in a welding method requiring strict target position accuracy such as laser welding. Will be possible.
[0041]
In these copying apparatuses 30, since the visual field range is narrow, it is necessary to correct the welding torch position in the welding process or to correct the butt welding position of the welding work (reset the work) in the conventional technology. However, in the present invention, the repeatability of the abutment position is improved, so that the position correction step can be omitted. It should be noted that the copying apparatus 30 may be of a type that detects a butting position by using laser reflection light, which is conventionally used.
[0042]
Further, in the embodiment shown in FIG. 3, a device 31 for judging the soundness of the welded portion is installed downstream of the welding torch 26, and the judging device 31 performs the judgment of the soundness of the welded portion together with the welding. Is shown. In this way, when the soundness of the welded portion is determined together with the welding by the determination device 31, it is possible to determine whether or not the welding is defective before performing the hydraulic bulging, thereby reducing the crack occurrence rate in the bulging. Will be able to It should be noted that a device for determining the profile of the surface of a weld bead by a conventionally used laser displacement meter may be used as this determination device.
[0043]
The present invention performs a welding process in a state where a material is fixed to a lower mold used in a final step of molding, when manufacturing a steel pipe having a different cross-sectional shape in an axial direction such as a tapered pipe. It is not limited to the order of the steps of C bending, U bending, and O bending.
[0044]
In addition, it is also a matter of the present invention to make the cross section of the tube end or the entire length into a rectangular shape or to process it into a shape close to the product shape. In the embodiment shown in FIGS. Although only the case of manufacturing a tapered tube having an increased length has been described, a modified tube whose circumferential length changes arbitrarily in the longitudinal direction may be manufactured. Needless to say, the shape of the metal plate as the material may be a curved shape that accurately matches the developed shape of the tapered tube, but may be a trapezoid or polygon approximated by a straight line. In this case, the metal plate used as the raw material is a single metal plate. However, a bonding plate of different materials or a bonding plate having a different thickness may be used. As a joining method, a tailored blank, a clad, or the like can be applied.
[0045]
2 and 3, the welding torch 26 is moved along the butt portion, but the welding may be performed by moving the material together with the lower mold.
[0046]
【The invention's effect】
As described above, according to the present invention, when manufacturing a deformed steel pipe whose cross-sectional shape changes in the axial direction such as a tapered pipe, for example, a state in which the material is set in the lower O-bending mold immediately after O-bending , It is possible to ensure high welding joint accuracy, and to improve the product quality.
[0047]
Further, according to the present invention, since an off-line welding machine is not required, a dedicated welding facility and operation personnel are not required, the lead time can be further shortened, and efficient production becomes possible. Of course, a product having a more complicated shape than before can be hydraulically bulged with good quality without molding defects.
[Brief description of the drawings]
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory view of a main part of an apparatus for manufacturing a deformed pipe for hydraulic bulging according to the present invention, wherein (a) is a longitudinal sectional view of a U bending apparatus, and (b) is a longitudinal section of an O bending apparatus. FIG. 2C is a perspective view of the welding device, and FIG. 2D is a diagram of FIG.
FIGS. 2A and 2B are schematic explanatory views showing a main part of another embodiment of the apparatus for manufacturing a deformed pipe for hydraulic bulging according to the present invention, wherein FIG. 2A is a longitudinal sectional view of a U-bending apparatus, and FIG. It is a longitudinal cross-sectional view of the U bending apparatus which is shaping | molding.
FIG. 3 is a schematic explanatory view of a main part showing still another embodiment of the apparatus for manufacturing a deformed pipe for hydraulic bulging according to the present invention, and FIG. 3 (a) is a longitudinal sectional view of a clamping apparatus when clamping by a roller. (B) is a side view of (a), (c) is a longitudinal sectional view of a clamp device for clamping by a holding die, and (d) is a view of (c) viewed from the side.
4A and 4B are explanatory views of a manufacturing process of a conventional deformed pipe for hydraulic bulge processing, wherein FIG. 4A is a perspective view showing a material, FIG. 4B is an explanatory view of a C-bending step of an end portion, and FIG. It is a perspective view of the material which carried out the C bending of both ends, (d) is explanatory drawing of a U bending process, (e) is a perspective view of the material which carried out U bending.
5 (a) and 5 (b) are explanatory views of a manufacturing process of a conventional deformed pipe for hydraulic bulging, in which (a) is an explanatory view of an O-bending process, (b) is a perspective view of a material subjected to O-bending, and (c) is FIG. 3 is an explanatory view of a welding process, and FIG. 4D is a perspective view of a material to be welded.
6A and 6B are explanatory views of a manufacturing process of another conventional deformed pipe for hydraulic bulging, in which FIG. 6A is an explanatory view of a C bending step of an end portion, and FIG. 6B is an explanatory view of a welding step.
7A and 7B are explanatory views of a manufacturing process of still another conventional deformed pipe for hydraulic bulging, wherein FIG. 7A is an explanatory view of a C bending step of an end portion, and FIG. 7B is an explanatory view of a U bending step; (C) is an explanatory view of a welding step.
[Explanation of symbols]
25a O-bending die 25b O-bending die 26 Welding torch 27a O-bending die 27b O-bending die 28 Roller type holding jig 29 Holding die 30 Copying device 31 Judging device

Claims (7)

  1. 軸方向に周長が任意に変化する液圧バルジ加工用異形素管を製造する方法において、
    最終曲げ成形の終了後、下金型に材料がセッティングされた状態にて、突合せ位置を溶接することを特徴とする液圧バルジ加工用異形素管の製造方法。
    In a method of manufacturing a deformed raw tube for hydraulic bulging in which the circumferential length changes arbitrarily in the axial direction,
    A method of manufacturing a deformed pipe for hydraulic bulging, comprising welding a butt position in a state where a material is set in a lower mold after completion of final bending.
  2. 請求項1記載の異形素管の製造方法において、
    下金型にセッティングした材料の溶接位置近傍をクランプした状態で溶接することを特徴とする液圧バルジ加工用異形素管の製造方法。
    In the method for producing a deformed pipe according to claim 1,
    A method for manufacturing a deformed pipe for hydraulic bulging, characterized in that a material set in a lower mold is welded in a state where the vicinity of a welding position is clamped.
  3. 請求項1又は2記載の異形素管の製造方法において、
    溶接時、周方向の溶接狙い位置を補正しつつ溶接することを特徴とする液圧バルジ加工用異形素管の製造方法。
    The method for producing a deformed pipe according to claim 1 or 2,
    A method for producing a deformed pipe for hydraulic bulging, wherein welding is performed while correcting a welding target position in a circumferential direction during welding.
  4. 請求項1〜3の何れか記載の異形素管の製造方法において、
    溶接と共に、溶接部の健全性の判定を行うことを特徴とする液圧バルジ加工用異形素管の製造方法。
    The method for producing a deformed pipe according to any one of claims 1 to 3,
    A method for producing a deformed pipe for hydraulic bulging, comprising determining the soundness of a welded portion together with welding.
  5. 曲げ成形装置と溶接装置を備えた、軸方向に周長が任意に変化する液圧バルジ加工用異形素管の製造装置において、
    前記溶接装置の上流側に、溶接位置近傍を固持するためのクランプ装置を設けたことを特徴とする液圧バルジ加工用異形素管の製造装置。
    In a manufacturing device of a deformed pipe for hydraulic bulging, the circumference of which is arbitrarily changed in the axial direction, comprising a bending device and a welding device,
    An apparatus for manufacturing a deformed pipe for hydraulic bulging, comprising a clamp device for holding a position near a welding position upstream of the welding device.
  6. 請求項5記載の異形素管の製造装置において、
    前記溶接装置の上流側に、溶接トーチを突合せ部に追従させるための倣い装置を設けたことを特徴とする液圧バルジ加工用異形素管の製造装置。
    The apparatus for manufacturing a deformed pipe according to claim 5,
    An apparatus for manufacturing a deformed pipe for hydraulic bulging, wherein a copying apparatus for causing a welding torch to follow a butt portion is provided upstream of the welding apparatus.
  7. 請求項5又は6記載の異形素管の製造装置において、
    前記溶接装置の下流側に、溶接部の健全性を判定する装置を設けたことを特徴とする液圧バルジ加工用異形素管の製造装置。
    The apparatus for manufacturing a deformed pipe according to claim 5 or 6,
    An apparatus for manufacturing a deformed pipe for hydraulic bulging, wherein an apparatus for judging the soundness of a weld is provided downstream of the welding apparatus.
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JP2016059938A (en) * 2014-09-17 2016-04-25 フタバ産業株式会社 Pipe manufacturing method
CN104589066A (en) * 2014-11-21 2015-05-06 浙江卓驰机械有限公司 Lining ring forming welder
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CN105234295A (en) * 2015-11-23 2016-01-13 安徽长江机床制造(集团)有限公司 Lower die base of conical lamp pole bending machine and machining method of lower die base
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