JP3758133B2

JP3758133B2 - Drawing method

Info

Publication number: JP3758133B2
Application number: JP2000309568A
Authority: JP
Inventors: 敬鈴村; 貞男石原
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2000-10-10
Filing date: 2000-10-10
Publication date: 2006-03-22
Anticipated expiration: 2020-10-10
Also published as: JP2002113528A

Description

【０００１】
【発明の属する技術分野】
本発明は、環状肩部及び該環状肩部の内周面に形成されたダイス穴を有する固定ダイスと可動パンチとを用い、固定ダイスのダイス穴に可動パンチを押し込むことにより、有底筒状体を成形する絞り成形方法に関する。
【０００２】
【従来の技術】
従来、底壁及び該底壁の外周縁端から起立する環状側壁を有する単純カップ状の有底筒状体を平板から成形したり、あるいは単純カップ状の有底筒状体の底壁にさらにカップ状の成形凹部を成形して段付きカップ状の有底筒状体を成形したりする場合、固定ダイスと可動パンチとを用いた絞り成形が利用されている。
【０００３】
例えば、図８に示すように、底壁９０ａ及び環状側壁９０ｂをもつ単純カップ状の有底筒状体をなす被加工体Ｗの底壁９０ａに、さらにカップ状の成形凹部９０ｃを成形して段付きカップ状の有底筒状体９０を成形する場合、従来、図８に示すような絞り成形方法及び装置が用いられている。
【０００４】
この絞り成形装置は、固定ダイス９１と、可動パンチ９２と、パッド９３と、エジェクタ９４とを備えている。固定ダイス９１は、成形前の単純カップ状の被加工体Ｗのうち環状側壁９０ｂの外周面に当接する第１側壁部９１ａと、成形前の単純カップ状の被加工体Ｗのうち底壁９０ａの外周縁部に当接する水平部９１ｂと、可動パンチ９１が進・退動するダイス穴９１ｃを形成する環状肩部９１ｄと、成形後の有底筒状体９０のうち成形凹部９０ｃの環状側壁の外周面に当接する第２側壁部９１ｅとを有している。可動パンチ９２は、昇降することにより、固定ダイス９１のダイス穴９１ｃに対して進・退動が可能となされている。パッド９３は、昇降可能で、固定ダイス９１の水平部９１ｂとの間で被加工体Ｗの底壁９０ａの外周縁部を挟持することにより、該底壁９０ａにおけるしわの発生を防止する。
【０００５】
上記絞り成形装置では、可動パンチ９２及びパッド９３を上昇させるとともに、エジェクタ９４を固定ダイス９１の水平部９１ｃの高さまで上昇させた状態で、固定ダイス９１の水平部９１ｃ及びエジェクタ９４上に単純カップ状の被加工体Ｗをセットする。そして、パッド９３を下降させて、被加工体Ｗの底壁９０ａの外周縁部を固定ダイス９１の水平部９１ｃとパッド９３との間で所定圧力で挟持する。このとき、被加工体Ｗの環状側壁９０ｂの内周面はパッド９３の外周面に接触するとともに、環状側壁９０ｂの外周面は固定ダイス９１の第１側壁部９１ａの内周面に接触している。この状態から、可動パンチ９２を下降させて固定ダイス９１のダイス穴９１ｃ内に可動パンチ９２を進動させ、エジェクタ９４を下降させながら該ダイス穴９１ｃ内に可動パンチ９２を押し込む。これにより、被加工体Ｗの底壁９０ａの外周縁部が固定ダイス９１の水平部９１ｃ及びパッド９３で挟持されるとともに環状肩部９１ｄで支持されながら、該底壁９０ａの中央部が可動パンチ９２の先端部でダイス穴９１ｃ内に押し込まれ、被加工体Ｗの底壁９０ａの中央部に成形凹部９０ｃが絞り成形される。その後、可動パンチ９２及びパッド９３を上昇させた後、エジェクタ９４で成形後の有底筒状体９０を押し出して脱型する。
【０００６】
【発明が解決しようとする課題】
ところが、上記したような従来の絞り成形方法及び装置では、可動パンチ９２により張り出し成形される被加工体Ｗの角部、すなわち可動パンチ９２の先端肩部９２ａに接触する成形凹部９０ｃの角部９０ｄに、引張応力の集中により割れ９０ｅが発生し易いという問題があった。
【０００７】
本発明は上記実情に鑑みてなされたものであり、可動パンチにより張り出し成形される被加工体の角部における引張応力の集中による割れを防止して、成形限界を向上させることのできる絞り成形方法を提供することを解決すべき技術課題とするものである。
【０００８】
【課題を解決するための手段】
上記課題を解決する本発明の絞り成形方法は、環状肩部及び該環状肩部の内周面に形成されたダイス穴を有する固定ダイスと、該ダイス穴に対して進・退動が可能とされた可動パンチとを用い、該固定ダイスの該ダイス穴に該可動パンチを進動させて押し込むことにより、有底筒状体を成形する絞り成形方法において、少なくとも成形途中に被加工体の表面に自己の型面が接触する可動型を上記可動パンチの進動に合わせて移動させることにより、該型面と、該型面と接触する該被加工体の表面との間に摩擦力を働かせ、該摩擦力によって移動する分の該被加工体の材料を成形促進方向に積極的に供給しながら成形することを特徴とするものである。
【００１０】
本発明の絞り成形方法では、少なくとも成形途中に被加工体の表面に自己の型面が接触する可動型を、可動パンチの進動に合わせて移動させることにより、該型面と、該型面と接触する該被加工体の表面との間に摩擦力を働かせ、該摩擦力によって移動する分の被加工体の材料を成形促進方向に積極的に供給しながら成形する。このように被加工体の材料を成形促進方向に積極的に供給することにより、可動パンチにより張り出し成形される被加工体の角部にも被加工体の材料が積極的に送り込まれる。このため、可動パンチにより張り出し成形される被加工体の角部において、引張応力の集中が緩和されるとともに材料不足も解消される。したがって、該角部における割れを防止して、成形限界を向上させることが可能となる。
本発明の絞り成形方法は、好適な態様において、底壁及び該底壁の外周縁端から一体に起立する環状側壁をもつ単純カップ状の前記被加工体の該底壁にさらに成形凹部を絞り成形して段付きカップ状の有底筒状体を成形するものであって、前記固定ダイスの外周側に配設された筒状の可動型の内周面と、前記被加工体の前記環状側壁の外周面との間に前記摩擦力を働かせる。
本発明の絞り成形方法は、好適な態様において、底壁及び該底壁の外周縁端から一体に起立する環状側壁をもつ単純カップ状の前記被加工体の該底壁にさらに成形凹部を絞り成形して段付きカップ状の有底筒状体を成形するものであって、前記固定ダイスの内周側に配設された筒状の可動型の内周面と、前記可動パンチにより成形されて成形途中にある前記成形凹部の外周面との間に前記摩擦力を働かせる。
本発明の絞り成形方法は、好適な態様において、底壁及び該底壁の外周縁端から一体に起立する環状側壁をもつ単純カップ状の前記被加工体の該底壁にさらに成形凹部を絞り成形して段付きカップ状の有底筒状体を成形するものであって、前記可動型は、上記被加工体の上記底壁の外周縁部を前記固定ダイスと共に挟持してしわ防止機能を果たしうるパッドであり、該パッドの外周面と、該被加工体の上記環状側壁の内周面との間に前記摩擦力を働かせる。
本発明の絞り成形方法は、好適な態様において、圧縮力付与機構を有する型を前記可動パンチの進動に合わせて移動させることにより、該圧縮力付与機構により前記被加工体に前記成形促進方向に圧縮力を付与しながら成形する。
上記課題を解決する本発明の絞り成形方法は、環状肩部及び該環状肩部の内周面に形成されたダイス穴を有する固定ダイスと、該ダイス穴に対して進・退動が可能とされた可動パンチとを用い、該固定ダイスの該ダイス穴に該可動パンチを進動させて押し込むことにより、有底筒状体を成形する絞り成形方法において、同一速度で同期的に移動可能な一対の可動型で被加工体を挟持し、該被加工体を挟持した両該可動型を上記可動パンチの進動に合わせて移動させることにより、該被加工体の材料を成形促進方向に積極的に供給しながら成形することを特徴とするものである。
【００１１】
【発明の実施の形態】
以下、本発明の実施の形態について、図面を参照しつつ説明する。
【００１２】
（実施形態１）
図１〜図４に示す本実施形態は、図３に示すように、底壁１ａ及びこの底壁１ａの外周縁端から一体に起立する環状側壁１ｂをもつ単純カップ状の有底筒状体をなす被加工体Ｗに対して絞り成形を施すことにより、底壁１ａにカップ状の成形凹部１ｃをさらに成形して段付きカップ状の有底筒状体１を成形するものである。
【００１３】
本実施形態に係る絞り成形装置では、固定ダイス２が固定台３上に載置されている。この固定ダイス２は、図４に示すように、上端面に形成された水平部２ａと、この水平部２ａの内周縁端に一体に設けられた環状肩部２ｂとを有し、環状肩部２ｂ及びこの環状肩部２ｂの下端に一体に設けられた環状内壁部２ｃの内周面に断面円形のダイス穴２ｄが形成されている。なお、環状内壁部２ｃの下端には、絞り成形された成形凹部１ｃの角部１ｄの外周面に当接する丸み段部２ｅが設けられるとともに、この丸み段部２ｅの内周縁端に断面円形の軸孔２ｆが設けられている。そして、固定ダイス２の軸孔２ｆにはエジェクタ４が摺動可能に配設されている。このエジェクタ４は、図示しない駆動手段（油圧シリンダ等）によりダイス穴２ｄ及び軸孔２ｆ内を昇降可能とされいる。
【００１４】
また、固定ダイス２の外周側上端部には環状凹段部２ｇが設けられ、この環状凹段部２ｇには断面円形の中心孔５ａをもつ略円筒状の第１可動型５が摺動可能に配設されている。なお、第１可動型５の中心孔５ａは、成形前の被加工体Ｗの環状側壁１ｂの外径と略同等の内径を有している。第１可動型５の下端には第１可動型５の外周面から遠心方向に突出する規制板５ｂが一体的に設けられている。この第１可動型５は、規制板５ｂの下面に当接する第１ノックアウトピン６を介して図示しない付勢手段（油圧シリンダ等）により上方に付勢されており、第１可動型５の外側に配設されたストッパ７の規制部７ａに規制板５ｂが当接することにより、第１可動型５の最上昇位置が規制されている。
【００１５】
なお、図１に示すように、規制板５ａとストッパ７の規制部７ａとの当接により第１可動型５が最上昇位置にあるとき、第１可動型５の上端は固定ダイス２にセットされた成形前の被加工体Ｗの環状側壁１ｂの上端よりも上方に位置する。また、最上昇位置にある第１可動型５の中心孔５ａの内周面は固定ダイス２にセットされた成形前の被加工体Ｗの環状側壁１ｂの外周面のほぼ全体に接触するとともに、最下降位置にある第１可動型５の中心孔５ａの内周面は成形後の被加工体Ｗ（有底筒状体１）の環状側壁１ｂの外周面のほぼ全体に接触する（図２参照）。
【００１６】
可動台８には保持板９を介して可動パンチ１０及びキラーブロック１１が固定され、この可動パンチ１０及びキラーブロック１１は図示しない駆動手段（油圧シリンダ等）により昇降可能とされた可動台８と共に同期的に昇降可能とされている。可動パンチ１０は、被加工体Ｗに成形する成形凹部１ｃの内周面形状に対応する成形外周面１０ａを有している。また、キラーブロック１１は、下降することにより第１可動型５の上面に当接して、該第１可動型５を上記付勢手段の付勢力に抗して下降させる。
【００１７】
また、可動台８には、第２ノックアウトピン１２を介して図示しない駆動手段（油圧シリンダ等）により昇降可能とされたパッド１３が保持されている。このパッド１３は略円筒状をなし、下降することにより、成形前及び成形中の被成形体Ｗの底壁１ａの外周縁部を固定ダイス２の水平部２ａとの間に所定圧力で挟持して、底壁１ａの外周縁部におけるしわの発生を防止する。なお、パッド１３の外周面は、成形前及び成形中の被加工体Ｗの環状側壁１ｂの内周面に接触している。
【００１８】
ここに、上記エジェクタ４を作動させる図示しない駆動手段、上記固定台８を作動させる図示しない駆動手段及び上記パッド１３を作動させる図示しない駆動手段は、いずれも図示しない制御手段により制御されている。
【００１９】
上記構成を有する絞り成形装置によれば、以下に示す方法により単純カップ状の有底筒状体をなす被加工体Ｗに対して絞り成形を施して底壁１ｂにカップ状の成形凹部１ｃをもつ段付きカップ状の有底筒状体１を成形することができる。
【００２０】
すなわち、図１に示すように、図示しない駆動手段の作動により、可動台８を上昇させて、可動台８とともに可動パンチ１０、キラーブロック１１及びパッド１３を上昇させておく。また、図示しない駆動手段の作動により、エジェクタ４を上昇させて、エジェクタ４の上端面と固定ダイス２の水平部２ａとを同一高さとしておく。なお、第１可動型５は、図示しない付勢手段の付勢力により、規制板５ｂとストッパ７の規制部７ａとが当接する最上昇位置にある。
【００２１】
この状態で、底壁１ａ及び環状側壁１ｂを有する単純カップ状の有底筒状体をなす被加工体Ｗを固定ダイス２の水平部１ａ及びエジェクタ４上にセットする。そして、図示しない駆動手段の作動によりパッド１３を下降させて、被加工体Ｗの底壁１ａの外周縁部を固定ダイス２の水平部１ａとパッド１３との間で挟持する（図１の状態）。なお、この水平部１ａ及びパッド１３による被加工体Ｗの挟圧力は、成形中、定圧に維持される。また、成形中常に、被加工体Ｗの環状側壁１ｂの内周面がパッド１３の外周面に接触するとともに、環状側壁１ｂの外周面が第１可動型５の中心孔５ａの内周面に接触している。
【００２２】
そして、図示しない駆動手段の作動により、固定台８と共に可動パンチ１０及びキラーブロック１１を同期的に下降させる。これにより、図１に示す状態から可動パンチ１０の先端面が被加工体Ｗの底壁１ａに当接するととともに、これとほぼ同時期にキラーブロック１１が第１可動型５に当接する。そのまま可動パンチ１０及びキラーブロック１１の下降を続け、固定ダイス２のダイス穴２ｄ内に可動パンチ１０を進動させ、エジェクタ４を下降させながら該ダイス穴２ｄ内に可動パンチ１０を押し込むとともに、第１可動型５の中心孔５ａの内周面を被加工体Ｗの環状側壁１ｂの外周面に摺接させながら図示しない付勢手段の付勢力に抗して第１可動型５をキラーブロック１１で押し下げる（図２の状態）。これにより、被加工体Ｗの底壁１ａの外周縁部が固定ダイス２の水平部２ａ及びパッド１３で挟持されるとともに環状肩部２ｂで支持されながら、該底壁１ａの中央部が可動パンチ１０の先端部でダイス穴２ｄ内に押し込まれ、被加工体Ｗの底壁１ａの中央部に成形凹部１ｃが絞り成形される。
【００２３】
その後、図示しない駆動手段の作動により、固定台８と共に可動パンチ１０、キラーブロック１１及びパッド１２を上昇させるとともに、エジェクタ４を上昇させて、成形後の有底筒状体１を脱型する。
【００２４】
この実施形態の絞り成形方法及びその装置では、第１可動型５の中心孔５ａの内周面が被加工体Ｗの環状側壁１ｂの外周面に成形中常に接触しており、可動パンチ１０による被加工体Ｗの成形が開始された以降は、該可動パンチ１０の下降と同期して、第１可動型５の内周面と被加工体Ｗの環状側壁１ｂの外周面とが摺接しながら該第１可動型５が下降する。このため、図２の点線丸部に拡大して模式的に示すように、被加工体Ｗの環状側壁１ｂの外周面と第１可動型５の内周面との界面には、該環状側壁１ｂの材料を成形促進方向（可動パンチ１０により成形される成形凹部１ｃの方向）に供給しようとする摩擦抵抗が働く。これにより、第１可動型５の内周面と接触する被加工体Ｗの材料を成形促進方向に積極的に供給しながら成形することができる。したがって、可動パンチ１０の先端肩部により張り出し成形される成形凹部１ｃの角部１ｄにも被加工体Ｗの材料が積極的に送り込まれる。このため、可動パンチ１０の先端肩部により張り出し成形される成形凹部１ｃの角部１ｄにおいて、引張応力の集中が緩和されるとともに材料不足も解消される。よって、該角部１ｄにおける割れを防止して、成形限界を向上させることが可能となる。
【００２５】
特に、本実施形態では、可動パンチ１０と共に下降するキラーブロック１１により、成形を開始した可動パンチ１０と同期的に同一速度で第１可動型５が下降することから、可動パンチ１０による被加工体Ｗの成形の進行に合わせて、被加工体Ｗの環状側壁１ｂの材料を成形促進方向に供給することができるので、より確実に上記成形凹部１ｃの角部１ｄにおける割れを防止して成形限界を向上させることが可能となる。
【００２６】
また、第１可動型５を下降させるキラーブロック１１及び可動パンチ１０は共に可動台８に固定保持されていることから、図示しない駆動手段による可動台８のみの動作を図示しない制御手段により制御することにより、可動パンチ１０及びキラーブロック１１の動作を制御することができるので、装置の簡素化に有利である。
【００２７】
ここに、この実施形態において、パッド１３を本発明の可動型として併用することも可能である。すなわち、図１の成形前の状態で、図示しない駆動手段の作動により、パッド１３を図１の状態から所定量上昇させておく。そして、可動パンチ１０のよる被加工体Ｗの成形の進行に合わせて、図示しない駆動手段を作動させてパッド１３を下降させる。これにより、被加工体Ｗの環状側壁１ｂの内周面とパッド１３の外周面との界面にも、該環状側壁１ｂの材料を成形促進方向に供給しようとする摩擦抵抗が働く。したがって、パッド１３及び第１可動型５により、環状側壁１ｂの内周面及び外周面の双方において該環状側壁１ｂの材料を成形凹部１ｃの方向に積極的に供給しようとする摩擦力が働き、より確実に上記成形凹部１ｃの角部１ｄにおける割れを防止して成形限界を向上させることが可能となる。このとき、パッド１３及び第１可動型５間の隙間を環状側壁１ｂの肉厚よりも狭くするとともに、パッド１３及び第１可動型５を同一速度で同期的に下降させるようにすれば、パッド１３及び第１可動型５間で環状側壁１ｂを挟持しながら該環状側壁１ｂの材料を成形促進方向に供給することもできる。なお、パッド１３を本発明の可動型として併用する場合は、成形の最終段階で、被加工体Ｗの底壁１ａの外周縁部をパッド１３と固定ダイス２の水平部２ａとの間で挟持して該底壁１ａの外周縁部におけるしわの発生を防止することになる。
【００２８】
また、この実施形態において、図８の従来の絞り成形装置と同様に第１可動型５と固定ダイス２とを一体化して、パッド１３のみを本発明の絞り成形方法に係る可動型として用いることもできる。
【００２９】
（実施形態２）
図５に示す本実施形態は、前記実施形態１に係る絞り成形装置において、第１可動型５の他に、固定ダイス２の内周側にも略円筒状の第２可動型１４を設けたものである。
【００３０】
すなわち、この絞り成形装置では、固定ダイス２の環状肩部２ｂの下方から固定ダイス２の下端まで延びる環状の案内凹部２ｈが設けられ、環状内壁部２ｃ、丸み段部２ｅ及び軸孔２ｆをもつ第２可動型１４が案内凹部２ｈに昇降可能に配設されている。そして、第２可動型１４は、第３ノックアウトピン１５を介して、図示しない制御手段により制御された駆動手段（油圧シリンダ等）により昇降可能とされている。
【００３１】
その他の構成は前記実施形態１と同様である。
【００３２】
したがって、この絞り成形装置は、前記実施形態１で説明した作用効果の他に、以下に示す作用効果も奏する。
【００３３】
すなわち、成形前の状態では、図５の左半分に示すように、図示しない駆動手段の作動により第２可動型１４を上昇させて、第２可動型１４の上端面を環状肩部２ｂの下端面に当接させた状態から、前記実施形態１と同様に、被加工体Ｗをセットするとともに被加工体Ｗの底壁１ａの外周縁部を固定ダイス２の水平部１ａとパッド１３との間で挟持する。
【００３４】
そして、前記実施形態１と同様に、固定台８と共に可動パンチ１０及びキラーブロック１１を同期的に下降させる。このとき、可動パンチ１０の先端部が被加工体Ｗの底壁１ａの中央部を固定ダイス２のダイス穴２ｄ内に押し込んで該先端部が第２可動型１４の上端部に到達したときに、図示しない駆動手段の作動により第２可動型１４を可動パンチ１０の進動に合わせて下降させる。こうして成形途中に被加工体Ｗの表面が接触する第２可動型１４を可動パンチ１０の進動に合わせて下降させながら成形し、被加工体Ｗの底壁１ａの中央部に成形凹部１ｃを絞り成形する。
【００３５】
その後、前記実施形態１と同様に成形後の有底筒状体１を脱型する。
【００３６】
このように本実施形態では、被加工体Ｗの環状側壁１ｂの外周面に成形中常に接触している前記第１可動型５を下降させるとともに、成形過程にある被加工体Ｗの成形凹部１ｃの外周面に成形途中に接触する第２可動型１４を可動パンチ１０の下降に合わせて下降させながら成形するので、成形過程にある成形凹部１ｃの外周面と第２可動型１４の内周面との界面にも、該成形凹部１ｃの材料を成形促進方向に供給しようとする摩擦抵抗が働き、これにより第２可動型１４の内周面と接触する被加工体Ｗの材料を成形促進方向に積極的に供給しながら成形することができる。したがって、可動パンチ１０の先端肩部により張り出し成形される成形凹部１ｃの角部１ｄに被加工体Ｗの材料がより積極的に送り込まれ、該角部１ｄにおける割れをより確実に防止して、成形限界をより向上させることが可能となる。
【００３７】
特に、本実施形態では、成形過程にある被加工体Ｗの成形凹部１ｃ、すなわち可動パンチ１０による成形が進行している部分の表面に接触する第２成形型１４を移動させているので、該部分の材料を成形促進方向により効果的に供給することができる。
【００３８】
ここに、この実施形態において、可動パンチ１０の外周面及び第２可動型１４の内周面間の隙間を成形過程にある成形凹部１ｃの肉厚よりも狭くするとともに、可動パンチ１０及び第２可動型１４を同一速度で下降させるようにすれば、可動パンチ１０及び第２可動型１４間で成形過程にある成形凹部１ｃを挟持しながら該成形凹部１ｃの材料を成形促進方向に供給することもできる。
【００３９】
（実施形態３）
図６に示す本実施形態は、前記実施形態１に係る絞り成形装置において、キラーブロック１１に圧縮力付与機構を設けたものである。
【００４０】
すなわち、この絞り成形装置では、キラーブロック１１の内周下端面に、固定ダイス２上にセットされた被加工体Ｗの環状側壁１ｂの上端部に嵌合可能な環状凹部１１ａが設けられている。
【００４１】
その他の構成は前記実施形態１と同様である。
【００４２】
したがって、この絞り成形装置は、前記実施形態１で説明した作用効果の他に、以下に示す作用効果も奏する。
【００４３】
すなわち、この絞り成形装置では、固定台８と共に可動パンチ１０及びキラーブロック１１が下降してキラーブロック１１が第１可動型５に当接すると同時に、該キラーブロック１１の環状凹部１１ａが被加工体Ｗの環状側壁１ｂの上端部と嵌合する。このため、そのまま可動パンチ１０及びキラーブロック１１の下降を続けることにより、被加工体Ｗの環状側壁１ｂの上端面を環状凹部１１ａで押圧して該環状側壁１ｂの材料を成形促進方向に押し込みながら、絞り成形することができる。したがって、可動パンチ１０の先端肩部により張り出し成形される成形凹部１ｃの角部１ｄに被加工体Ｗの材料がより積極的に送り込まれ、該角部１ｄにおける割れをより確実に防止して、成形限界をより向上させることが可能となる。
【００４４】
また、キラーブロック１１の環状凹部１１ａから被加工体Ｗの上端面に成形過程で積極的に圧縮力が付与されることから、絞り成形に必要な材料体積よりも過剰な材料を押し込むことが可能となる。このため、被加工体Ｗに成形凹部１ｃを絞り成形して段付きカップ状の有底筒状体１を成形すると同時に、該有底筒状体１の特定部位、例えば底壁１ａや環状側壁１ｂの肉厚を部分的に増大させることも可能となる。
【００４５】
なお、この実施形態では、被加工体Ｗの端面に圧縮力を付与するための圧縮力付与機構として、キラーブロック１１に設けられた環状凹部１１ａを採用したが、可動パンチ１０のダイス穴２ｄ内への進動に合わせて下降可能となるように、キラーブロック１１とは別体として設けられたスリーブパンチ等を採用することも可能である。
【００４６】
（実施形態４）
図７に示す本実施形態は、前記実施形態１に係る絞り成形装置において、固定ダイス２の水平部２ａの代わりにテーパ部２ｉを設けたものである。
【００４７】
すなわち、この絞り成形装置では、固定ダイス２の上端に、中心側に向かうに連れて下方、すなわち成形促進方向に傾斜した傾斜面をもつテーパ部２ｉが設けられている。また、パッド１３の下端も該テーパ部２ｉと対応するテーパ部面１３ｉとされている。
【００４８】
その他の構成は前記実施形態１と同様である。
【００４９】
したがって、この絞り成形装置は、前記実施形態１で説明した作用効果の他に、以下に示す作用効果も奏する。
【００５０】
すなわち、この絞り成形装置では、エジェクタ４の上端面が固定ダイス２のテーパ部２ｉの上端と略同一高さとなるまでエジェクタ４を上昇させた状態で、該エジェクタ４上に被加工体Ｗをセットする。その後は、前記実施形態１と同様の方法で絞り成形をする。
【００５１】
なお、パッド１３は、可動パッド１０による成形が進み、被加工体Ｗの底壁１ｂが固定ダイス２のテーパ部２ｉに当接した以降に、該底壁１ｂを該テーパ部２ｉと共に所定圧力で挟持し得るように下降させればよい。また、この実施形態で成形される有底筒状体１’は、前記実施形態１で成形した有底筒状体１における底壁１ａ及び環状壁部１ｂの代わりにテーパフランジ部１ｅを有している。
【００５２】
このようにダイス穴２ｄを形成する環状肩部２ｂと一体にテーパ部２ｉを設けることにより、ダイス穴２ｄに導かれる材料流入部に傾斜面が形成されるので、被加工体Ｗの材料をテーパ部２ｉからダイス穴２ｄ内へ容易に押し込むことが可能となり、材料の変形抵抗及び摩擦抵抗を低減させることができる。したがって、可動パンチ１０の先端肩部により張り出し成形される成形凹部１ｃの角部１ｄに被加工体Ｗの材料がより積極的に送り込まれ、該角部１ｄにおける割れをより確実に防止して、成形限界をより向上させることが可能となる。
【００５３】
なお、上述の実施形態では、いずれも単純カップ状の被加工体Ｗから段付きカップ状の有底筒状体１を成形する例について説明したが、本発明はこれに限定されるものではない。
【００５４】
例えば、底壁及びこの底壁の外周縁端から一体に起立する環状側壁をもつ単純カップ状で、かつ、浅くて大径の有底筒状体をなす被加工体Ｗから、単純カップ状で、かつ、深くて小径の有底筒状体を成形したり、底壁及び環状側壁をもつ単純カップ状の被加工体Ｗから、環状側壁の端面からさらに遠心方向に延びる水平フランジ部をもつ逆ハット状の有底筒状体を成形したり、あるいは平板状の被加工体Ｗから単純カップ状の有底筒状体を成形したりする場合にも本発明を適用することが可能である。具体的には、前記実施形態１で示した絞り成形方法において、ダイス穴２ｄの深さを深くして可動パンチ１０による押し込み量を多くすることにより、単純カップ状で、かつ、深くて小径の有底筒状体を成形したり、逆ハット状の有底筒状体を成形することができる。また、平板状の被加工体Ｗから単純カップ状の有底筒状体を成形する場合は、前記実施形態２で示した絞り成形装置のように、固定ダイス２の内周側に可動型１４を設け、固定ダイス２の水平部２ａ上に平板状の被加工体Ｗをセットするとともにその外周縁部を該水平部２ａ及びパッド１３ａ間で挟持しつつ絞り成形すればよい。
【００６０】
【発明の効果】
以上詳述したように、本発明に係る絞り成形方法によれば、可動型により被加工体の材料を成形促進方向に積極的に供給しながら成形することができるので、可動パンチにより張り出し成形される被加工体の角部における引張応力の集中による割れを防止して、成形限界を向上させることが可能となる。
【００６１】
また、被加工体の材料が成形促進方向に供給されれば、材料の変形抵抗を低減させることができるので、成形荷重の低下や成形型の寿命向上等にもつながり、コスト面でも有利となる。
【図面の簡単な説明】
【図１】実施形態１の絞り成形方法及びその装置に係り、成形前の状態を示す断面図である。
【図２】実施形態１の絞り成形方法及びその装置に係り、成形後の状態を示す断面図である。
【図３】実施形態１の絞り成形方法及びその装置に係り、成形前の被加工体及び成形後の有底筒状体を示す断面図である。
【図４】実施形態１の絞り成形方法及びその装置に係り、成形前の状態にある固定ダイス、可動型及びエジェクタ等を示す断面図である。
【図５】実施形態２の絞り成形方法及びその装置に係り、左半分が成形前の状態を示し、右半分が成形後の状態を示す断面図である。
【図６】実施形態３の絞り成形方法及びその装置に係り、成形後の状態を示す断面図である。
【図７】実施形態４の絞り成形方法及びその装置に係り、成形後の状態を示す断面図である。
【図８】従来の絞り成形方法及びその装置に係り、成形後の状態を示断面図である。
【符号の説明】
Ｗ…被加工体１…有底筒状体
１ａ…底壁１ｂ…環状側壁
１ｃ…成形凹部１ｄ…角部
２…固定ダイス２ａ…水平部
２ｂ…環状肩部２ｄ…ダイス穴
４…エジェクタ５…第１可動型
１０…可動パンチ１１…キラーブロック
１３…パッド１４…第２可動型[0001]
BACKGROUND OF THE INVENTION
  The present invention uses a fixed die having a ring shoulder and a die hole formed on the inner peripheral surface of the ring shoulder and a movable punch, and by pushing the movable punch into the die hole of the fixed die, Drawing method to form bodyTo the lawRelated.
[0002]
[Prior art]
Conventionally, a simple cup-shaped bottomed cylindrical body having a bottom wall and an annular side wall standing up from the outer peripheral edge of the bottom wall is molded from a flat plate, or further added to the bottom wall of a simple cup-shaped bottomed cylindrical body. When forming a cup-shaped forming recess to form a stepped cup-shaped bottomed cylindrical body, drawing using a fixed die and a movable punch is used.
[0003]
For example, as shown in FIG. 8, a cup-shaped recess 90c is further formed on the bottom wall 90a of the workpiece W having a simple cup-shaped bottomed cylindrical body having a bottom wall 90a and an annular side wall 90b. When forming the stepped cup-shaped bottomed cylindrical body 90, a drawing method and apparatus as shown in FIG. 8 are conventionally used.
[0004]
This drawing apparatus includes a fixed die 91, a movable punch 92, a pad 93, and an ejector 94. The fixed die 91 includes a first side wall portion 91a that contacts the outer peripheral surface of the annular side wall 90b in the simple cup-shaped workpiece W before molding, and a bottom wall 90a of the simple cup-shaped workpiece W before molding. A horizontal portion 91b that abuts on the outer peripheral edge of the metal plate, an annular shoulder portion 91d that forms a die hole 91c in which the movable punch 91 advances and retreats, and an annular side wall of the molded concave portion 90c of the bottomed cylindrical body 90 after molding. 2nd side wall part 91e which contact | abuts to the outer peripheral surface. The movable punch 92 can be moved up and down with respect to the die hole 91c of the fixed die 91 by moving up and down. The pad 93 can be moved up and down, and the outer peripheral edge of the bottom wall 90 a of the workpiece W is sandwiched between the pad 93 and the horizontal portion 91 b of the fixed die 91, thereby preventing wrinkles from occurring on the bottom wall 90 a.
[0005]
In the drawing apparatus, the movable punch 92 and the pad 93 are raised and the ejector 94 is raised to the height of the horizontal portion 91c of the fixed die 91, and the simple cup is placed on the horizontal portion 91c and the ejector 94 of the fixed die 91. A workpiece W is set. Then, the pad 93 is lowered and the outer peripheral edge portion of the bottom wall 90 a of the workpiece W is sandwiched between the horizontal portion 91 c of the fixed die 91 and the pad 93 with a predetermined pressure. At this time, the inner peripheral surface of the annular side wall 90 b of the workpiece W is in contact with the outer peripheral surface of the pad 93, and the outer peripheral surface of the annular side wall 90 b is in contact with the inner peripheral surface of the first side wall portion 91 a of the fixed die 91. Yes. From this state, the movable punch 92 is lowered to move the movable punch 92 into the die hole 91c of the fixed die 91, and the movable punch 92 is pushed into the die hole 91c while the ejector 94 is lowered. Thus, the outer peripheral edge portion of the bottom wall 90a of the workpiece W is sandwiched between the horizontal portion 91c and the pad 93 of the fixed die 91 and supported by the annular shoulder portion 91d, while the central portion of the bottom wall 90a is movable punch. The tip 92 is pushed into the die hole 91c, and a molding recess 90c is drawn at the center of the bottom wall 90a of the workpiece W. Then, after raising the movable punch 92 and the pad 93, the bottomed cylindrical body 90 after shaping | molding is extruded by the ejector 94, and it demolds.
[0006]
[Problems to be solved by the invention]
However, in the conventional drawing method and apparatus as described above, the corner portion 90d of the forming recess 90c that contacts the corner portion of the workpiece W that is stretched and formed by the movable punch 92, that is, the tip shoulder portion 92a of the movable punch 92. In addition, there is a problem that the crack 90e is likely to occur due to the concentration of the tensile stress.
[0007]
  The present invention has been made in view of the above circumstances, and is a drawing method capable of preventing cracking due to concentration of tensile stress at the corner of a workpiece stretched by a movable punch and improving the molding limit.The lawThis is a technical problem to be solved.
[0008]
[Means for Solving the Problems]
  The drawing method of the present invention that solves the above-described problem is a fixed die having a circular shoulder portion and a die hole formed on the inner peripheral surface of the annular shoulder portion, and can be moved forward and backward with respect to the die hole. In the drawing method of forming a bottomed tubular body by moving the movable punch into the die hole of the fixed die and pushing it into the die hole,at leastBy moving the movable mold whose own mold surface is in contact with the surface of the workpiece during molding according to the movement of the movable punch,Friction force is applied between the mold surface and the surface of the workpiece that is in contact with the mold surface.Molding is performed while positively supplying the material of the workpiece in the molding acceleration direction.
[0010]
  Drawing method of the present inventionIn lawIsat leastBy moving the movable mold whose mold surface is in contact with the surface of the workpiece during molding, according to the movement of the movable punch,Friction force is applied between the mold surface and the surface of the workpiece that is in contact with the mold surface.Molding while actively supplying the material of the workpiece in the direction of molding promotion. In this way, by actively supplying the material of the workpiece in the forming acceleration direction, the material of the workpiece is positively fed also into the corner portion of the workpiece that is stretched and formed by the movable punch. For this reason, the concentration of tensile stress is eased at the corners of the workpiece that is stretched and formed by the movable punch, and the material shortage is also eliminated. Therefore, it is possible to prevent cracks at the corners and improve the molding limit.
  In a preferred embodiment of the drawing method of the present invention, in a preferred embodiment, a molding recess is further drawn in the bottom wall of the simple cup-shaped workpiece having a bottom wall and an annular side wall standing integrally from the outer peripheral edge of the bottom wall. A stepped cup-shaped bottomed cylindrical body is formed by molding, and an inner peripheral surface of a cylindrical movable mold disposed on the outer peripheral side of the fixed die, and the annular shape of the workpiece The frictional force is applied to the outer peripheral surface of the side wall.
  In a preferred embodiment of the drawing method of the present invention, in a preferred embodiment, a molding recess is further drawn in the bottom wall of the simple cup-shaped workpiece having a bottom wall and an annular side wall standing integrally from the outer peripheral edge of the bottom wall. A stepped cup-shaped bottomed cylindrical body is formed by molding using a cylindrical movable mold inner peripheral surface disposed on the inner peripheral side of the fixed die and the movable punch. Thus, the frictional force is applied to the outer peripheral surface of the molding recess in the middle of molding.
  In a preferred embodiment of the drawing method of the present invention, in a preferred embodiment, a molding recess is further drawn in the bottom wall of the simple cup-shaped workpiece having a bottom wall and an annular side wall standing integrally from the outer peripheral edge of the bottom wall. A stepped cup-shaped bottomed cylindrical body is formed by molding, and the movable mold sandwiches the outer peripheral edge of the bottom wall of the workpiece together with the fixed die to prevent wrinkles. A pad that can be achieved, and the frictional force is applied between the outer peripheral surface of the pad and the inner peripheral surface of the annular side wall of the workpiece.
  In a preferred embodiment, the drawing method of the present invention, in a preferred embodiment, the mold having the compression force application mechanism is moved in accordance with the movement of the movable punch, whereby the forming force is applied to the workpiece by the compression force application mechanism. Molding while applying compressive force.
  The drawing method of the present invention that solves the above-described problem is a fixed die having a circular shoulder portion and a die hole formed on the inner peripheral surface of the annular shoulder portion, and can be moved forward and backward with respect to the die hole. In the drawing method for forming a bottomed tubular body, the movable punch can be moved synchronously at the same speed by moving the movable punch into the die hole of the fixed die and pushing it into the die hole. A workpiece is sandwiched between a pair of movable molds, and both movable molds sandwiching the workpiece are moved in accordance with the movement of the movable punch, so that the material of the workpiece is positively promoted in the molding promoting direction. It is characterized in that it is molded while being supplied.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
(Embodiment 1)
As shown in FIG. 3, the present embodiment shown in FIGS. 1 to 4 is a simple cup-shaped bottomed cylindrical body having a bottom wall 1 a and an annular side wall 1 b erected integrally from the outer peripheral edge of the bottom wall 1 a. The cup-shaped bottomed cylindrical body 1 is formed by further forming a cup-shaped concave portion 1c on the bottom wall 1a by drawing the workpiece W having the following structure.
[0013]
In the drawing apparatus according to this embodiment, the fixed die 2 is placed on the fixed base 3. As shown in FIG. 4, the fixed die 2 has a horizontal portion 2a formed on the upper end surface, and an annular shoulder portion 2b integrally provided at the inner peripheral edge of the horizontal portion 2a. A die hole 2d having a circular cross section is formed on the inner peripheral surface of 2b and an annular inner wall 2c integrally provided at the lower end of the annular shoulder 2b. The lower end of the annular inner wall 2c is provided with a rounded step 2e that comes into contact with the outer peripheral surface of the corner 1d of the drawn recess 1c, and a circular cross section at the inner peripheral edge of the rounded step 2e. A shaft hole 2f is provided. An ejector 4 is slidably disposed in the shaft hole 2 f of the fixed die 2. The ejector 4 can be moved up and down in the die hole 2d and the shaft hole 2f by driving means (not shown) such as a hydraulic cylinder.
[0014]
Further, an annular concave step 2g is provided on the outer peripheral side upper end of the fixed die 2, and a substantially cylindrical first movable mold 5 having a center hole 5a having a circular cross section is slidable on the annular concave step 2g. It is arranged. The center hole 5a of the first movable mold 5 has an inner diameter substantially equal to the outer diameter of the annular side wall 1b of the workpiece W before molding. The lower end of the first movable mold 5 is integrally provided with a regulating plate 5 b that protrudes in the centrifugal direction from the outer peripheral surface of the first movable mold 5. The first movable mold 5 is biased upward by a biasing means (not shown) such as a hydraulic cylinder via a first knockout pin 6 that contacts the lower surface of the regulating plate 5 b. When the restricting plate 5b comes into contact with the restricting portion 7a of the stopper 7 disposed in the position, the highest position of the first movable mold 5 is restricted.
[0015]
As shown in FIG. 1, when the first movable die 5 is at the highest position due to the contact between the restriction plate 5 a and the restriction portion 7 a of the stopper 7, the upper end of the first movable die 5 is set on the fixed die 2. It is located above the upper end of the annular side wall 1b of the workpiece W before being formed. Further, the inner peripheral surface of the center hole 5a of the first movable mold 5 at the highest position contacts almost the entire outer peripheral surface of the annular side wall 1b of the workpiece W before molding set in the fixed die 2, The inner peripheral surface of the center hole 5a of the first movable mold 5 at the lowest position contacts almost the entire outer peripheral surface of the annular side wall 1b of the workpiece W (bottomed cylindrical body 1) after molding (FIG. 2). reference).
[0016]
A movable punch 10 and a killer block 11 are fixed to the movable table 8 through a holding plate 9, and the movable punch 10 and the killer block 11 are moved up and down by a driving means (such as a hydraulic cylinder) not shown. It can be moved up and down synchronously. The movable punch 10 has a molding outer peripheral surface 10a corresponding to the inner peripheral surface shape of the molding recess 1c to be molded into the workpiece W. Further, the killer block 11 comes into contact with the upper surface of the first movable die 5 by lowering, and lowers the first movable die 5 against the urging force of the urging means.
[0017]
The movable table 8 holds a pad 13 that can be moved up and down by a driving means (not shown) such as a hydraulic cylinder via a second knockout pin 12. The pad 13 has a substantially cylindrical shape and descends so that the outer peripheral edge of the bottom wall 1a of the molding target W before and during molding is sandwiched between the horizontal portion 2a of the fixed die 2 with a predetermined pressure. Thus, the generation of wrinkles at the outer peripheral edge of the bottom wall 1a is prevented. The outer peripheral surface of the pad 13 is in contact with the inner peripheral surface of the annular side wall 1b of the workpiece W before and during molding.
[0018]
Here, a drive means (not shown) for operating the ejector 4, a drive means (not shown) for operating the fixed base 8, and a drive means (not shown) for operating the pad 13 are all controlled by a control means (not shown).
[0019]
According to the drawing apparatus having the above-described configuration, the workpiece W that forms a simple cup-shaped bottomed cylindrical body is subjected to drawing by the following method, and the cup-shaped molding recess 1c is formed in the bottom wall 1b. A stepped cup-shaped bottomed cylindrical body 1 can be formed.
[0020]
That is, as shown in FIG. 1, the movable table 8 is raised by the operation of a driving means (not shown), and the movable punch 10, the killer block 11 and the pad 13 are raised together with the movable table 8. In addition, the ejector 4 is raised by the operation of a driving means (not shown) so that the upper end surface of the ejector 4 and the horizontal portion 2a of the fixed die 2 are set to the same height. The first movable die 5 is at the highest position where the restricting plate 5b and the restricting portion 7a of the stopper 7 come into contact with each other by an urging force of an urging means (not shown).
[0021]
In this state, a workpiece W having a simple cup-shaped bottomed cylindrical body having a bottom wall 1a and an annular side wall 1b is set on the horizontal portion 1a and the ejector 4 of the fixed die 2. Then, the pad 13 is lowered by the operation of the driving means (not shown), and the outer peripheral edge portion of the bottom wall 1a of the workpiece W is sandwiched between the horizontal portion 1a of the fixed die 2 and the pad 13 (state of FIG. 1). ). The clamping pressure of the workpiece W by the horizontal portion 1a and the pad 13 is maintained at a constant pressure during molding. In addition, the inner peripheral surface of the annular side wall 1 b of the workpiece W is always in contact with the outer peripheral surface of the pad 13 during molding, and the outer peripheral surface of the annular side wall 1 b is in contact with the inner peripheral surface of the center hole 5 a of the first movable mold 5. In contact.
[0022]
  Then, the movable punch 10 and the killer block 11 are lowered synchronously together with the fixed base 8 by the operation of the driving means (not shown). Thereby, the tip surface of the movable punch 10 comes into contact with the bottom wall 1 a of the workpiece W from the state shown in FIG. 1, and the killer block 11 comes into contact with the first movable mold 5 almost at the same time. The movable punch 10 and the killer block 11 continue to descend, the movable punch 10 is moved into the die hole 2d of the fixed die 2, and the die hole is lowered while the ejector 4 is lowered.2dThe movable punch 10 is pushed in, and the inner peripheral surface of the center hole 5a of the first movable mold 5 is slidably brought into contact with the outer peripheral surface of the annular side wall 1b of the workpiece W to resist the biasing force of a biasing means (not shown). TheFirstMovable type5Is pushed down by the killer block 11 (state shown in FIG. 2). Thereby, the outer peripheral edge portion of the bottom wall 1a of the workpiece W is sandwiched between the horizontal portion 2a of the fixed die 2 and the pad 13 and supported by the annular shoulder portion 2b, while the central portion of the bottom wall 1a is movable punch. 10 is pushed into the die hole 2d, and a molding recess 1c is drawn at the center of the bottom wall 1a of the workpiece W.
[0023]
Thereafter, the movable punch 10, the killer block 11, and the pad 12 are raised together with the fixed base 8 by the operation of a driving means (not shown), and the ejector 4 is raised to remove the molded bottomed cylindrical body 1.
[0024]
  In the drawing method and apparatus of this embodiment, the inner peripheral surface of the center hole 5a of the first movable mold 5 is always in contact with the outer peripheral surface of the annular side wall 1b of the workpiece W during molding, and the movable punch 10 After the molding of the workpiece W is started, the inner peripheral surface of the first movable mold 5 and the outer peripheral surface of the annular side wall 1b of the workpiece W are slidably in contact with the lowering of the movable punch 10. The first movable mold 5 is lowered. For this reason, as schematically shown enlarged to the dotted-lined circle in FIG. 2, the annular side wall is located at the interface between the outer peripheral surface of the annular side wall 1 b of the workpiece W and the inner peripheral surface of the first movable mold 5. 1b material forming direction (molding recess formed by movable punch 10)1cFriction resistance to be supplied in the direction of Thereby, it can shape | mold, supplying the material of the to-be-processed body W which contacts the internal peripheral surface of the 1st movable mold | type 5 actively in a shaping | molding acceleration | stimulation direction. Therefore, a molding recess that is stretched by the tip shoulder of the movable punch 101cCorner1dAlso, the material of the workpiece W is positively fed. For this reason, the molding recessed part overhang-molded by the front-end | tip shoulder part of the movable punch 101cCorner1d, The concentration of tensile stress is eased and the material shortage is resolved. Therefore, the corner1dIt is possible to prevent cracking and improve the molding limit.
[0025]
  In particular, in the present embodiment, the first movable mold 5 is lowered at the same speed synchronously with the movable punch 10 that has started forming by the killer block 11 that is lowered together with the movable punch 10. Since the material of the annular side wall 1b of the workpiece W can be supplied in the molding promoting direction in accordance with the progress of the molding of W, the molding recess is more reliably performed.1cCorner1dIt is possible to prevent cracking and improve the molding limit.
[0026]
Further, since both the killer block 11 and the movable punch 10 for lowering the first movable mold 5 are fixedly held by the movable table 8, the operation of only the movable table 8 by the driving unit (not shown) is controlled by the control unit (not shown). Thus, the operations of the movable punch 10 and the killer block 11 can be controlled, which is advantageous for simplification of the apparatus.
[0027]
  Here, in this embodiment, the pad 13 can be used together as the movable type of the present invention. That is, in the state before molding in FIG. 1, the pad 13 is raised by a predetermined amount from the state in FIG. Then, as the forming of the workpiece W by the movable punch 10 proceeds, the driving means (not shown) is operated to lower the pad 13. As a result, a frictional resistance that tries to supply the material of the annular side wall 1b in the molding promoting direction also acts on the interface between the inner peripheral surface of the annular side wall 1b of the workpiece W and the outer peripheral surface of the pad 13. Accordingly, the pad 13 and the first movable mold 5 cause a frictional force to actively supply the material of the annular side wall 1b in the direction of the molding recess 1c on both the inner peripheral surface and the outer peripheral surface of the annular side wall 1b. More secure molding recess1cCorner1dIt is possible to prevent cracking and improve the molding limit. At this time, if the gap between the pad 13 and the first movable mold 5 is made narrower than the thickness of the annular side wall 1b, and the pad 13 and the first movable mold 5 are lowered synchronously at the same speed, the pad It is also possible to supply the material of the annular side wall 1b in the molding promoting direction while sandwiching the annular side wall 1b between the 13 and the first movable mold 5. When the pad 13 is used as the movable mold of the present invention, the outer peripheral edge of the bottom wall 1a of the workpiece W is sandwiched between the pad 13 and the horizontal part 2a of the fixed die 2 at the final stage of molding. Thus, generation of wrinkles at the outer peripheral edge of the bottom wall 1a is prevented.
[0028]
Further, in this embodiment, the first movable die 5 and the fixed die 2 are integrated as in the conventional drawing device of FIG. 8, and only the pad 13 is used as the movable die according to the drawing method of the present invention. You can also.
[0029]
(Embodiment 2)
In the present embodiment shown in FIG. 5, in the drawing apparatus according to the first embodiment, in addition to the first movable die 5, a substantially cylindrical second movable die 14 is provided on the inner peripheral side of the fixed die 2. Is.
[0030]
That is, in this drawing apparatus, an annular guide recess 2h extending from below the annular shoulder 2b of the fixed die 2 to the lower end of the fixed die 2 is provided, and has an annular inner wall 2c, a rounded step 2e, and a shaft hole 2f. The second movable mold 14 is disposed in the guide recess 2h so as to be movable up and down. The second movable die 14 can be moved up and down by a driving means (such as a hydraulic cylinder) controlled by a control means (not shown) via a third knockout pin 15.
[0031]
Other configurations are the same as those of the first embodiment.
[0032]
Therefore, in addition to the operational effects described in the first embodiment, the drawing apparatus has the following operational effects.
[0033]
That is, in the state before molding, as shown in the left half of FIG. 5, the second movable mold 14 is raised by the operation of a driving means (not shown) so that the upper end surface of the second movable mold 14 is below the annular shoulder 2b. As in the first embodiment, the workpiece W is set and the outer peripheral edge of the bottom wall 1a of the workpiece W is placed between the horizontal portion 1a of the fixed die 2 and the pad 13 from the state of contacting the end surface. Hold between.
[0034]
Then, similarly to the first embodiment, the movable punch 10 and the killer block 11 are lowered synchronously together with the fixed base 8. At this time, when the tip of the movable punch 10 pushes the center of the bottom wall 1 a of the workpiece W into the die hole 2 d of the fixed die 2 and the tip reaches the upper end of the second movable die 14. Then, the second movable die 14 is lowered in accordance with the movement of the movable punch 10 by the operation of the driving means (not shown). In this way, the second movable die 14 that contacts the surface of the workpiece W during molding is molded while being lowered in accordance with the movement of the movable punch 10, and a molding recess 1 c is formed at the center of the bottom wall 1 a of the workpiece W. Draw molding.
[0035]
Thereafter, similarly to the first embodiment, the bottomed cylindrical body 1 after molding is removed.
[0036]
  As described above, in the present embodiment, the first movable mold 5 that is always in contact with the outer peripheral surface of the annular side wall 1b of the workpiece W is lowered and the molding recess 1c of the workpiece W in the molding process is lowered. Since the second movable die 14 that is in contact with the outer peripheral surface of the mold is lowered while the movable punch 10 is lowered, the outer peripheral surface of the molding recess 1c and the inner peripheral surface of the second movable die 14 in the molding process are formed. The frictional resistance that tries to supply the material of the molding recess 1c in the molding promoting direction also acts on the interface between the workpiece and the workpiece W in contact with the inner peripheral surface of the second movable die 14 in the molding promoting direction. It can be molded while actively supplying Therefore, a molding recess that is stretched by the tip shoulder of the movable punch 101cCorner1dThe material of the workpiece W is more actively fed into the corner1dIt is possible to more reliably prevent cracking and improve the molding limit.
[0037]
In particular, in the present embodiment, the second molding die 14 that is in contact with the molding recess 1c of the workpiece W in the molding process, that is, the surface of the portion where molding by the movable punch 10 is in progress is moved. The material of the portion can be effectively supplied in the direction of promoting molding.
[0038]
Here, in this embodiment, the gap between the outer peripheral surface of the movable punch 10 and the inner peripheral surface of the second movable mold 14 is made narrower than the thickness of the molding recess 1c in the molding process, and the movable punch 10 and the second If the movable die 14 is lowered at the same speed, the material of the molding recess 1c is supplied in the molding promoting direction while sandwiching the molding recess 1c in the molding process between the movable punch 10 and the second movable die 14. You can also.
[0039]
(Embodiment 3)
The present embodiment shown in FIG. 6 is a drawing forming apparatus according to the first embodiment, in which a compression force applying mechanism is provided on the killer block 11.
[0040]
That is, in this drawing apparatus, an annular recess 11 a that can be fitted to the upper end of the annular side wall 1 b of the workpiece W set on the fixed die 2 is provided on the lower end surface of the inner periphery of the killer block 11. .
[0041]
Other configurations are the same as those of the first embodiment.
[0042]
Therefore, in addition to the operational effects described in the first embodiment, the drawing apparatus has the following operational effects.
[0043]
  That is, in this drawing apparatus, the movable punch 10 and the killer block 11 are moved down together with the fixed base 8 so that the killer block 11 contacts the first movable mold 5, and at the same time, the annular recess 11a of the killer block 11 is formed on the workpiece. The upper end of the W-shaped annular side wall 1b is fitted. For this reason, by continuing the descent of the movable punch 10 and the killer block 11 as it is, the upper end surface of the annular side wall 1b of the workpiece W is pressed by the annular recess 11a and the material of the annular side wall 1b is pushed in the molding promoting direction. Can be drawn. Therefore, a molding recess that is stretched by the tip shoulder of the movable punch 101cCorner1dThe material of the workpiece W is more actively fed into the corner1dIt is possible to more reliably prevent cracking and improve the molding limit.
[0044]
In addition, since a compressive force is positively applied from the annular recess 11a of the killer block 11 to the upper end surface of the workpiece W during the molding process, it is possible to push in an excess material beyond the material volume required for drawing. It becomes. For this reason, the molding concave portion 1c is drawn on the workpiece W to form the stepped cup-shaped bottomed cylindrical body 1, and at the same time, specific parts of the bottomed cylindrical body 1, for example, the bottom wall 1a and the annular side wall It is also possible to partially increase the thickness of 1b.
[0045]
In this embodiment, the annular recess 11a provided in the killer block 11 is employed as a compression force application mechanism for applying a compression force to the end surface of the workpiece W. However, in the die hole 2d of the movable punch 10 It is also possible to employ a sleeve punch or the like provided separately from the killer block 11 so as to be able to descend in accordance with the forward movement.
[0046]
(Embodiment 4)
The present embodiment shown in FIG. 7 is a drawing forming apparatus according to the first embodiment, in which a tapered portion 2 i is provided instead of the horizontal portion 2 a of the fixed die 2.
[0047]
That is, in this drawing apparatus, a tapered portion 2i having an inclined surface that is inclined downward toward the center, that is, in the molding promoting direction, is provided at the upper end of the fixed die 2. The lower end of the pad 13 is also a tapered portion surface 13i corresponding to the tapered portion 2i.
[0048]
Other configurations are the same as those of the first embodiment.
[0049]
Therefore, in addition to the operational effects described in the first embodiment, the drawing apparatus has the following operational effects.
[0050]
That is, in this drawing apparatus, the workpiece W is set on the ejector 4 in a state where the ejector 4 is raised until the upper end surface of the ejector 4 becomes substantially the same height as the upper end of the tapered portion 2 i of the fixed die 2. To do. Thereafter, drawing is performed in the same manner as in the first embodiment.
[0051]
The pad 13 is formed by the movable pad 10, and after the bottom wall 1b of the workpiece W comes into contact with the tapered portion 2i of the fixed die 2, the bottom wall 1b is pressed together with the tapered portion 2i at a predetermined pressure. What is necessary is just to descend | fall so that it can clamp. Moreover, the bottomed cylindrical body 1 ′ molded in this embodiment has a tapered flange portion 1e instead of the bottom wall 1a and the annular wall portion 1b in the bottomed cylindrical body 1 molded in the first embodiment. ing.
[0052]
  By providing the tapered portion 2i integrally with the annular shoulder portion 2b that forms the die hole 2d in this way, an inclined surface is formed in the material inflow portion that is guided to the die hole 2d, so that the material of the workpiece W is tapered. It can be easily pushed into the die hole 2d from the portion 2i, and the deformation resistance and frictional resistance of the material can be reduced. Therefore, a molding recess that is stretched by the tip shoulder of the movable punch 101cCorner1dThe material of the workpiece W is more actively fed into the corner1dIt is possible to more reliably prevent cracking and improve the molding limit.
[0053]
In the above-described embodiment, the example in which the stepped cup-shaped bottomed cylindrical body 1 is formed from the simple cup-shaped workpiece W has been described, but the present invention is not limited to this. .
[0054]
For example, a simple cup shape having a bottom wall and an annular side wall standing integrally from the outer peripheral edge of the bottom wall, and a simple cup shape from a workpiece W having a shallow and large-diameter bottomed cylindrical body. And forming a deep, small-diameter bottomed cylindrical body, or from a simple cup-shaped workpiece W having a bottom wall and an annular side wall, and having a horizontal flange portion extending further in the centrifugal direction from the end face of the annular side wall The present invention can also be applied to a case where a hat-shaped bottomed cylindrical body is molded or a simple cup-shaped bottomed cylindrical body is molded from a plate-shaped workpiece W. Specifically, in the drawing method shown in the first embodiment, by increasing the depth of the die hole 2d and increasing the amount of pressing by the movable punch 10, it is simple cup-shaped and deep and has a small diameter. A bottomed cylindrical body can be molded, or an inverted hat-shaped bottomed cylindrical body can be molded. Further, when a simple cup-shaped bottomed cylindrical body is formed from the plate-shaped workpiece W, the movable die 14 is formed on the inner peripheral side of the fixed die 2 as in the drawing apparatus shown in the second embodiment. And a flat plate-like workpiece W is set on the horizontal portion 2a of the fixed die 2, and the outer peripheral edge portion is drawn while being sandwiched between the horizontal portion 2a and the pad 13a.
[0060]
【The invention's effect】
  As detailed above, the drawing method according to the present invention.To the lawAccording to the present invention, it is possible to mold while actively supplying the material of the workpiece in the molding promotion direction by the movable die, so that cracks due to concentration of tensile stress at the corner of the workpiece to be stretched and molded by the movable punch can be prevented. It is possible to prevent and improve the molding limit.
[0061]
Further, if the material of the workpiece is supplied in the direction of molding promotion, the deformation resistance of the material can be reduced, leading to a reduction in molding load, an improvement in the life of the molding die, etc., which is advantageous in terms of cost. .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a state before molding according to the drawing method and apparatus of Embodiment 1;
FIG. 2 is a cross-sectional view showing a state after molding according to the drawing method and apparatus of Embodiment 1;
FIG. 3 is a cross-sectional view showing a workpiece before molding and a bottomed cylindrical body after molding according to the drawing method and apparatus of Embodiment 1;
FIG. 4 is a cross-sectional view showing a fixed die, a movable die, an ejector, and the like in a state before forming according to the drawing method and apparatus of Embodiment 1;
FIG. 5 is a cross-sectional view showing a state before molding and a right half after molding according to the drawing method and apparatus of Embodiment 2;
FIG. 6 is a cross-sectional view showing a state after molding according to the drawing method and apparatus of Embodiment 3;
FIG. 7 is a cross-sectional view showing a state after molding according to the drawing method and apparatus of Embodiment 4;
FIG. 8 is a cross-sectional view showing a state after molding according to a conventional drawing method and apparatus.
[Explanation of symbols]
W ... Workpiece 1 ... Bottomed cylindrical body
1a ... bottom wall 1b ... annular side wall
1c ... Molding recess 1d ... Corner
2 ... Fixed die 2a ... Horizontal part
2b ... annular shoulder 2d ... die hole
4 ... Ejector 5 ... First movable type
10 ... Moveable punch 11 ... Killer block
13 ... Pad 14 ... Second movable type

Claims

An annular shoulder, a fixed die having a die hole formed on the inner peripheral surface of the annular shoulder, and a movable punch capable of moving forward and backward with respect to the die hole are used. In the drawing method for forming a bottomed tubular body by moving the movable punch into a die hole and pushing it,
By moving a movable mold whose own mold surface contacts the surface of the workpiece at least during molding in accordance with the movement of the movable punch, the mold surface and the workpiece to be in contact with the mold surface A drawing method characterized in that a forming is performed while a frictional force is applied to the surface and the material of the workpiece to be moved by the frictional force is actively supplied in a forming acceleration direction.

A stepped cup-shaped bottomed cylindrical body in which a molding recess is further drawn on the bottom wall of the simple cup-shaped workpiece having a bottom wall and an annular side wall standing integrally from the outer peripheral edge of the bottom wall. And molding
2. The frictional force is applied between an inner peripheral surface of a cylindrical movable mold disposed on the outer peripheral side of the fixed die and an outer peripheral surface of the annular side wall of the workpiece. The drawing method of description.

A stepped cup-shaped bottomed cylindrical body in which a molding recess is further drawn on the bottom wall of the simple cup-shaped workpiece having a bottom wall and an annular side wall standing integrally from the outer peripheral edge of the bottom wall. And molding
The friction force is applied between the inner peripheral surface of a cylindrical movable mold disposed on the inner peripheral side of the fixed die and the outer peripheral surface of the molding recess formed by the movable punch and in the middle of molding. The drawing method according to claim 1 or 2.

A stepped cup-shaped bottomed cylindrical body in which a molding recess is further drawn on the bottom wall of the simple cup-shaped workpiece having a bottom wall and an annular side wall standing integrally from the outer peripheral edge of the bottom wall. And molding
The movable die is a pad that can sandwich the outer peripheral edge of the bottom wall of the workpiece together with the fixed die to perform a wrinkle prevention function, and the outer peripheral surface of the pad and the annular side wall of the workpiece The draw forming direction according to claim 1, wherein the frictional force is exerted between the inner peripheral surface of the first and second inner surfaces.

A mold having a compression force application mechanism is moved in accordance with the movement of the movable punch, and is molded while applying a compression force in the forming acceleration direction to the workpiece by the compression force application mechanism. The drawing method according to claim 1, 2, 3, or 4.

An annular shoulder, a fixed die having a die hole formed on the inner peripheral surface of the annular shoulder, and a movable punch capable of moving forward and backward with respect to the die hole are used. In the drawing method for forming a bottomed cylindrical body by moving the movable punch into a die hole and pushing it,
A workpiece is sandwiched between a pair of movable molds that can be moved synchronously at the same speed, and both the movable molds that sandwich the workpiece are moved in accordance with the movement of the movable punch. A drawing method characterized in that molding is carried out while actively supplying body material in the direction of molding promotion.