JP4360125B2

JP4360125B2 - Molding method

Info

Publication number: JP4360125B2
Application number: JP2003149454A
Authority: JP
Inventors: 希人加藤
Original assignee: Aisin Seiki Co Ltd; Aisin Corp
Current assignee: Aisin Corp
Priority date: 2003-05-27
Filing date: 2003-05-27
Publication date: 2009-11-11
Anticipated expiration: 2023-05-27
Also published as: JP2004351436A

Description

【０００１】
【発明の属する技術分野】
本発明は成形方法および成形型に関する。
【０００２】
【従来の技術】
圧入や嵌め合いに使用する鍔付または段付の高精度円筒を製造する方法として、棒材や板材より鍛造や絞り成形により、鍔付または段付の円筒を作製し、それを素形材として圧入や嵌め合いの精度を確保するために切削や研削の機械加工する方法がある。この方法は、機械加工するため精度は確保できるものの生産性が低くコスト高となる。また板材より絞り成形した素形材を、絞り成形と連動した塑性加工で円筒の内外径をしごき加工する方法もある。この方法は生産性は高いが、成形型から取り出したとき、鍔または段差に近い部分と離れた部分で形状剛性差のためスプリングバック（弾性変形）量が異なるので、微少にラッパ状となり円筒度が低下する問題点がある。円筒度が低下すると、圧入や嵌め合いに使用する場合に必要な精度を確保できない問題点がある。
【０００３】
従来技術１として、特許文献１には、絞り加工で成形した有底筒状素材の筒部の板厚減少部の板厚を増加させた後にしごき加工する成形方法が開示されている。
【０００４】
【特許文献１】
特開平８−１４１６６２号公報（請求項１等）
【０００５】
【発明が解決しようとする課題】
しかしながら、従来技術１は、筒状部分の剛性（板厚が薄い）場合、しごき成形型から取り出したときに、上記と同様にスプリングバック差が生じ、筒状部分の精度が確保できない問題点があった。
【０００６】
本発明は上記課題を解決したもので、鍔付の筒状部材の成形において、筒状部の形状精度を向上できる成形方法および成形型を提供する。
【０００７】
【課題を解決するための手段】
上記技術的課題を解決するために、本発明の請求項１において講じた技術的手段（以下、第１の技術的手段と称する。）は、筒状部と筒状部の一端に屈曲部を有して連続し且つ外向きに延びる鍔状部とを有するワークの筒状部を、屈曲部の内側コーナー部位に対応する箇所において鍔状部側のみに突出するとともにその頂部が内側コーナー部位の屈曲箇所の対応部位から外向きに離間するよう設けられた凸部を一方に備えたパンチとダイスによりしごき加工するしごき加工工程と、板部材からワークの形状を絞り形成する絞り加工工程と、ワークの筒状部の内周面を外側コーナー部位から離れるにつれ漸次縮径する形状に形成するリストライク工程とが、しごき加工工程の前に設けられ、絞り加工工程の後にリストライク工程を行い、その後、筒状部の内周面が外側コーナー部位から離れるにつれ漸次縮径する形状のワークにしごき加工工程を行い、凸部は、頂部から内側コーナー部位の屈曲箇所の対応部位にかけて傾斜面を有し、しごき加工工程の終期に、凸部により鍔状部の材料を筒状部側に流動させることを特徴とする成形方法である。
【０００８】
上記第１の技術的手段による効果は、以下のようである。
【０００９】
パンチ又はダイスにおける凸部は、その頂部から内側コーナー部位の屈曲箇所の対応部位にかけて傾斜面を有している。そして、しごき加工工程終期に該傾斜面により鍔状部の材料を筒状部側へ流動させるので、鍔状部に生じる引張応力を効果的に緩和できる。それゆえ、筒状部の軸方向のスプリングバック量の差を低減できるため、筒状部の形状精度を向上できる。また、筒状部の内周面が外側コーナー部位から離れるにつれ漸次縮径する形状のワークを用いて前記しごき加工工程を行うため、しごき加工工程終期に外側コーナー部位に近いほど筒状部と成形型との隙間が多く、鍔状部の材料の筒状部側への流動を促進し、筒状部の形状精度をより向上できる。更に、筒状部の内周面が外側コーナー部位から離れるにつれ漸次縮径する形状である前記しごき加工工程に用いるワークをしごき加工工程の前のリストライク工程により形成可能になるため、しごき加工工程終期に外側コーナー部位に近いほど筒状部と成形型との隙間が多く、鍔状部の材料の筒状部側への流動を促進し、筒状部の形状精度をより向上できる。
【００１０】
上記技術的課題を解決するために、本発明の請求項２において講じた技術的手段（以下、第２の技術的手段と称する。）は、前記ワークの前記鍔状部が前記凸部を有するパンチ又はダイスのどちらか一方の凸部の頂部と、他方のパンチ又はダイスの前記鍔状部に対向する部分とが前記鍔状部に当接し、前記筒状部の内周面における前記屈曲部の前記外側コーナー部位側と前記他方のパンチ又はダイスとの間に隙間が存在した状態から前記しごき加工工程終期は開始されることを特徴とする、請求項１に記載の成形方法である。
【００１１】
上記第２の技術的手段による効果は、以下のようである。
【００１２】
筒状部の内周面における屈曲部の外側コーナー部位側と他方のパンチ又はダイスとの間に隙間が存在した状態から前記しごき加工工程終期は開始されるため、鍔状部の材料の筒状部側への流動が容易となる。それゆえ、鍔状部に生じる引張応力の増加を抑えられ、筒状部の形状精度をより好適に向上できる。
【００２５】
【発明の実施の形態】
以下、本発明の実施例について、図面に基づいて説明する。図１は実施例のワークの断面図である。図２は実施例のワークを製造する工程を説明する説明図である。図３は実施例のしごき加工を説明する説明図である。
【００２６】
ワーク１は鍔付および段付筒状部材であり、第１筒状部１１、第１鍔状部１２、第２筒状部１３、第２鍔状部１４から構成されている。第１筒状部１１は略円筒形状で、その一方端は内側にわずかに折り曲がっている。第１筒状部１１の外周面は真円筒形状で、内周面は図１の上方に向かって広がるテーパ面（傾斜面）となっている。そのテーパ面の傾斜角Ｒ１は０．１７度である。第１鍔状部１２は第１筒状部１１の他方端に連続する外向きの鍔状部である。すなわち、第１鍔状部１２は、第１筒状部１１の上端に屈曲部１６を有しており、屈曲部１６で第１筒状部１１に連続している。第２筒状部１３は第１鍔状部１２の第１筒状部１１と連続する一方端側の反対側に連続する略円筒形状である。第２筒状部１３の外周面は真円筒形状で、内周面は図１の上方に向かって広がるテーパ面（傾斜面）となっている。そのテーパ面の傾斜角Ｒ２も０．１７度である。第２鍔状部１４は第２筒状部１３の一端に連続する外向きの鍔状部である。すなわち、第２鍔状部１４は、第２筒状部１３の上端に屈曲部１６を有しており、屈曲部１６で第２筒状部１３に連続している。第１鍔状部１２は径の異なる第１筒状部１１と第２筒状部１３を連結する段差部であるが、第１筒状部１１から見れば鍔状部であり、本発明でいう鍔状部には、筒状部の一端に連続する外向きの鍔状部分であればすべて含まれる。ワーク１の材質は圧延鋼材ＳＰＣ２８０である。ワーク１の材質としては、これに限らず、熱延圧延鋼材ＳＰＨ２８０、アルミニウム材、銅材など、しごき加工可能な金属材料が使用できる。
【００２７】
ワーク１は図２に示す上の工程から下の工程に至る工程を経て製造される。ブランキング工程で板厚２．６ｍｍの円板状板材を用意する。第１絞り工程から第３絞り工程に至る絞り成形にて鍔付有底円筒部材２４を製造する。第４絞り工程の絞り成形にて段付形状に成形する。リストライク（逃がしテーパ成形）工程において第１筒状部１１と第２筒状部１３のテーパ面を成形する。リストライク工程は一般的に行われる鍛造と類似の半密閉成形により行う。最後に底穴ピアス工程で底部２６ａを打ち抜き穴部１５を形成する。こうしてワーク１が完成される。
【００２８】
図３を用いて成形型を説明する。パンチ４０は、先端部４１、第１棒状部４２、第２棒状部４３および基部４４が設けられている。先端部４１はワーク１の穴部１５に挿入する部分である。第１棒状部４２は一端が先端部４１に連続し、他端が第２棒状部４３に連続し、ワーク１の第１筒状部１１に挿入する部分である。その外周側はほぼ真円筒形状であるが、第２棒状部４３に連続する部分は外側に断面Ｒ形状となっている。第１棒状部４２の外形寸法によって、しごき加工後の第１筒状部１１の内径寸法が決められる。
【００２９】
第２棒状部４３はワーク１の第２筒状部１３に挿入する部分である。第２棒状部４３の第１棒状部４２に連続する側の第１棒状部４２より突出した面はワーク１の第１鍔状部１２の上面に当接する部分である。第２棒状部４３の外周側は真円筒形状である。第２棒状部４３の外形寸法によって、しごき加工後の第２筒状部１３の内径寸法が決められる。第２棒状部４３の第１棒状部４２に連続する側と反対側は基部４４と連続している。基部４４の第２棒状部４３より突出した部分の下面はワーク１の第２鍔状部１４の上面に当接する部分である。
【００３０】
ダイス３０は、第１しごき部３１と第２しごき部３２が設けられている。第１しごき部３１は第１筒状部１１をしごき加工し、その内外径を成形する部分である。第１しごき部３１の第１鍔状部１２の下面に対向する上面には第１鍔状部１２側に突出する第１凸部３３が設けられている。第１凸部３３は断面形状が三角形状（略二等辺三角形）である。第１凸部３３は第１しごき部３１の上面の内周側端部に設けられている。第１凸部３３は円形状の稜線を有するリング形状である。第１しごき部３１の内径寸法によって、しごき加工後の第１筒状部１１の外径寸法が決められる。第１しごき部３１の内径側には適正なしごき導入角が設けられ、内径面と上面との角部には適正なＲ面取りがされている。
【００３１】
第２しごき部３２は第２筒状部１３をしごき加工し、その内外径を成形する部分である。第２しごき部３２の第２鍔状部１４の下面に対向する上面には第２鍔状部１４側に突出する第２凸部３４が設けられている。第２凸部３４も第１凸部３３と同様には断面形状が三角形状（略二等辺三角形）で、その上面の内周側端部に設けられ、円形状の稜線（頂部）を有するリング形状である。第１凸部３３及び第２凸部３４は、該稜線からワーク１における内側コーナー部位の屈曲箇所の対応部位にかけて傾斜面３５を有する。第２しごき部３２の内径寸法によって、しごき加工後の第２筒状部１３の外径寸法が決められる。第２しごき部３２の内径側には適正なしごき導入角が設けられ、内径面と上面との角部には適正なＲ面取りがされている。
【００３２】
次にしごき加工工程について説明する。はじめにパンチ４０にワーク１が嵌合される。こうしてワーク１の内周側にパンチ４０が挿入された状態となる。このとき第１棒状部４２は第１筒状部１１にほぼ嵌合され、第２棒状部４３は第２筒状部１３にほぼ嵌合される。また第２棒状部４３の下面は第１鍔状部１２の上面に当接し、基部４４の下面は第２鍔状部１４の上面に当接する。このときダイス３０はワーク１から離れた下方に存在する。
【００３３】
続いて、ワーク１を嵌合したままパンチ４０を下降し、ダイス３０の内部に挿入する。ワーク１は、下降にしたがって第１筒状部１１が第１しごき部３１で、第２筒状部１３が第２しごき部３２でしごき加工され、第１鍔状部１２の下面が第１凸部３３の稜線に当接し、第２鍔状部１４の下面が第２凸部３４の稜線に当接し、図３の左図（中心線から左側の図）の状態になる。このしごき加工時に、第１筒状部１１の外径寸法は第１しごき部３１の内径寸法に縮径されるとともに、第１筒状部１１の内周側のテーパ面によって第１棒状部４２との間にできた隙間に第１筒状部１１の材料が流動し、第１筒状部１１の内径寸法が第１棒状部４２の外径寸法になる。また第２筒状部１３の外径寸法は第２しごき部３２の内径寸法に縮径されるとともに、第２筒状部１３の内周側のテーパ面によって第２棒状部４３との間にできた隙間に第２筒状部１３の材料が流動し、第２筒状部１３の内径寸法が第２棒状部４３の外径寸法になる
さらにパンチ４０を下降すると、図３の右図（中心線から右側の図）のように、第１鍔状部１２に第１凸部３３が侵入し、第１凸部３３の稜線より内周側の第１鍔状部１２の材料が第１筒状部１１側に流動し、第１凸部３３の稜線より外周側の第１鍔状部１２の材料が第２筒状部１３側に流動する。同時に第２鍔状部１４に第２凸部３４が侵入し、第２凸部３４の稜線より内周側の第２鍔状部１４の材料が第２筒状部１３側に流動し、第２凸部３４の稜線より外周側の第２鍔状部１４の材料がその外周側に流動する。
【００３４】
パンチ４０の加圧力が予め決められた所定圧力になるか、予め決められた所定位置になったとき、パンチ４０の下降を停止する。パンチ４０が停止してから所定時間経過後、パンチ４０を上昇し、ワーク１を取り出すと、製品が完成する。
【００３５】
この製品では、第１鍔状部１２の材料が第１筒状部１１側に流動し、第２鍔状部１４の材料が第２筒状部１３側に流動しているので、第１筒状部１１や第２筒状部１３のしごき加工による縮径に伴って第１鍔状部１２や第２鍔状部１４に生ずる外向きの引張応力を緩和することができる。その結果、第１筒状部１１や第２筒状部１３の軸方向のスプリングバック量の差を低減でき、第１筒状部１１や第２筒状部１３の形状精度（円筒度）を向上できる。実施例のように第１凸部３３や第２凸部３４が内周側端部に設けられているので、材料の流動効果が高められている。
【００３６】
さらに実施例では、第１筒状部１１や第２筒状部１３の内周側にテーパ面が形成され、それぞれ第１鍔状部１２や第２鍔状部１４に近いほど第１棒状部４２や第２棒状部４３との間の隙間が多いので、第１鍔状部１２の第１筒状部１１側への材料流動や第２鍔状部１４の第２筒状部１３側への材料流動を容易にし、第１筒状部１１や第２筒状部１３の形状精度（円筒度）をより向上できる。実施例ではテーパ面の傾斜角は０．１７度であったが、これに限定されず、製品形状や材質等によって適宜選択できる。しかし、テーパ面の傾斜角は、望ましくは０．０６〜０．５７度がよく、さらに望ましくは０．１４〜０．２９度、０．１４〜０．２０度がよい。
【００３７】
また実施例では第１棒状部４２の第２棒状部４３に連続する部分が外側に断面Ｒ形状を有しているので、第１筒状部１１の上端部分とパンチ４０の第１棒状部４２の間に隙間が存在する。この隙間により第１鍔状部１２の第１筒状部１１側への材料流動を促進し、第１筒状部１１の形状精度（円筒度）をより向上できる。
【００３８】
実施例では第１凸部３３や第２凸部３４によって第１鍔状部１２や第２鍔状部１４の材料を第１筒状部１１側や第２筒状部１３側に流動させているが、他の方法で流動させてもよい。例えば、ダイスとパンチで鍔状部を挟持する圧力を鍔状部が塑性変形する応力とすることによって流動させることもできる。材料流動量が少なくてもよい製品の場合には十分効果を発揮できる。この場合、鍔状部に当接するダイスやパンチの面を、ダイスとパンチの間隔が外周ほど狭くなるように形成されていると、より効果的に材料を流動させることができる。第１鍔状部１２のように段差部を形成する鍔状部の場合、ダイス３０の第２しごき部３２で外周側が拘束されているので、ダイスとパンチで挟持する圧力だけで第１筒状部１１側に材料流動させる効果が大きい。
【００３９】
第１凸部３３や第２凸部３４はその断面形状が三角形状であるが、他の断面形状のものを使用することもできる。図４は、種々の凸部の断面形状を説明する説明図である。図４（ａ）は実施例の断面形状（三角形状）である。図４（ｂ）は凸部の断面形状が半円状のものである。図４（ｃ）は凸部の断面形状が台形形状のものである。いずれの凸部形状も内周側に傾斜面が存在するが、傾斜面が存在しなくともよい。しかし傾斜面の存在により、鍔状部の筒状部側への材料流動を促進できる。
【００４０】
鍔状部の潰し部分（凸部や圧力により潰される部分）の形状や量は鍔状部の大きさや製品形状・材料特性等からくるスプリングバック量によって使い分ける。それに対応して凸部の断面形状や大きさを設定すればよい。
【００４１】
実施例の凸部は、ダイスの鍔状部に対向する部分に設けられているが、パンチの鍔状部に対向する部分に設けてもよいし、両方に設けてもよい。いずれも実施例と同様の効果を奏する。凸部により鍔状部に潰し部分の後が残るので、製品の必要に応じて適宜選択すればよい。
【００４２】
実施例では筒状部は円筒形状であるが楕円筒形状その他の筒状形状でもよい。また実施例では穴部１５が設けられているが、有底筒状でもよいし、有底に小穴部が複数形成されているものでもよい。これらの形状は製品形状によって適宜選択される。
【００４３】
実施例ではテーパ面で傾斜面を形成しているが、傾斜面であればテーパ面である必要はない。また傾斜面は必ずしも連続的に傾斜していなくともよい。さらに傾斜面がなくてよい。
【００４４】
こうして本発明では機械加工等の工程を追加することなしに形状精度に優れた筒状部を有する鍔付筒状部材を製造できるので、低コストで製造できる。
【００４５】
【発明の効果】
以上のように、本発明は、筒状部と該筒状部の一端に連続する外向きの鍔状部を有するワークの前記筒状部をパンチとダイスによりしごき加工するしごき加工工程が設けられ、該しごき加工工程の終期に前記鍔状部の材料を前記筒状部側に流動させることを特徴とする成形方法、あるいは筒状部と該筒状部の一端に連続する外向きの鍔状部を有するワークの前記筒状部をしごき加工するパンチとダイスを有する成形型であって、前記パンチの前記鍔状部に対向する部分、前記ダイスの前記鍔状部に対向する部分の少なくとも一方に前記鍔状部側に突出する凸部が設けられていることを特徴とする成形型であるので、筒状部の形状精度を向上することができる。
【図面の簡単な説明】
【図１】実施例のワークの断面図
【図２】実施例のワークを製造する工程を説明する説明図
【図３】実施例のしごき加工を説明する説明図
【図４】種々の凸部の断面形状を説明する説明図
【符号の説明】
１…ワーク
１１…第１筒状部（筒状部）
１２…第１鍔状部（鍔状部）
１３…第２筒状部（筒状部）
１４…第２鍔状部（鍔状部）
１６…屈曲部
３０…ダイス
３３…第１凸部（凸部）
３４…第２凸部（凸部）
３５…傾斜面
４０…パンチ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molding method and a mold.
[0002]
[Prior art]
As a method of manufacturing a brazed or stepped high-precision cylinder used for press-fitting and fitting, a brazed or stepped cylinder is produced from a bar or plate material by forging or drawing, and this is used as a base material. There are methods of machining for cutting and grinding to ensure the accuracy of press-fitting and fitting. This method can ensure accuracy because it is machined, but has low productivity and high cost. There is also a method in which an inner and outer diameter of a cylinder is wrought by plastic working in conjunction with drawing forming from a shaped material drawn from a plate material. This method is highly productive, but when removed from the mold, the amount of springback (elastic deformation) differs due to the difference in shape rigidity between the part near the ridge or the step and the part away from it. There is a problem that decreases. When the cylindricity is lowered, there is a problem that it is not possible to ensure the accuracy required for press-fitting or fitting.
[0003]
As prior art 1, Patent Document 1 discloses a molding method in which ironing is performed after increasing the plate thickness of the thickness-reduced portion of the cylindrical portion of the bottomed cylindrical material formed by drawing.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 8-141662 (Claim 1 etc.)
[0005]
[Problems to be solved by the invention]
However, in the case of the prior art 1, when the cylindrical portion is rigid (thickness is thin), when it is taken out from the ironing mold, a springback difference occurs as described above, and the accuracy of the cylindrical portion cannot be ensured. there were.
[0006]
This invention solves the said subject and provides the shaping | molding method and shaping | molding die which can improve the shape precision of a cylindrical part in shaping | molding of a cylindrical member with a brazing.
[0007]
[Means for Solving the Problems]
In order to solve the above technical problem, the technical means taken in claim 1 of the present invention (hereinafter referred to as first technical means) includes a cylindrical portion and a bent portion at one end of the cylindrical portion. The cylindrical portion of the workpiece having a flange-like portion that is continuous and extends outwardly protrudes only at the flange-like portion side at a location corresponding to the inner corner portion of the bent portion, and the top portion is an inner corner portion. A squeezing process for squeezing with a punch and a die provided on one side with a convex portion provided so as to be spaced outward from the corresponding part of the bending part, and a drawing process for squeezing the shape of the workpiece from the plate member, A re-striking process for forming the inner peripheral surface of the cylindrical part of the workpiece into a shape that gradually decreases in diameter as it moves away from the outer corner part is provided before the ironing process, and the re-sticking process is performed after the drawing process, afterwards The ironing process is performed on the workpiece having a shape that gradually decreases in diameter as the inner peripheral surface of the cylindrical portion moves away from the outer corner portion, and the convex portion has an inclined surface from the top portion to the corresponding portion of the bent portion of the inner corner portion. The molding method is characterized in that, at the end of the ironing process, the material of the bowl-shaped portion is caused to flow toward the cylindrical portion by the convex portion.
[0008]
The effects of the first technical means are as follows.
[0009]
The convex part in the punch or die has an inclined surface from the top part to the corresponding part of the bent part of the inner corner part. And since the material of a bowl-shaped part is made to flow to the cylindrical part side with this inclined surface at the end of a ironing process, the tensile stress which arises in a bowl-shaped part can be relieve | moderated effectively. Therefore, since the difference in the amount of springback in the axial direction of the cylindrical portion can be reduced, the shape accuracy of the cylindrical portion can be improved. Further, since the ironing process is performed using a workpiece having a shape that gradually decreases in diameter as the inner peripheral surface of the cylindrical part moves away from the outer corner part, the cylindrical part and the molding are formed closer to the outer corner part at the end of the ironing process. There are many gaps with the mold, the flow of the material of the bowl-shaped part to the cylindrical part side can be promoted, and the shape accuracy of the cylindrical part can be further improved. Furthermore, since the workpiece used in the ironing process, which has a shape that gradually decreases in diameter as the inner peripheral surface of the cylindrical part moves away from the outer corner part, can be formed by the restructuring process before the ironing process, the ironing process The closer to the outer corner portion at the end, the more the gap between the cylindrical portion and the mold, which promotes the flow of the material of the bowl-shaped portion to the cylindrical portion side, thereby further improving the shape accuracy of the cylindrical portion.
[0010]
In order to solve the above technical problem, the technical means taken in claim 2 of the present invention (hereinafter referred to as second technical means) is that the hook-shaped portion of the workpiece has the convex portion. The top of the convex part of either the punch or the die and the part of the other punch or die facing the bowl-shaped part are in contact with the bowl-shaped part, and the bent part on the inner peripheral surface of the cylindrical part 2. The molding method according to claim 1, wherein the end of the ironing process is started from a state in which a gap exists between the outer corner portion side of the first punch or the die .
[0011]
The effects of the second technical means are as follows.
[0012]
Since the end of the ironing process starts from a state where a gap exists between the outer corner portion side of the bent portion on the inner peripheral surface of the cylindrical portion and the other punch or die, the cylindrical shape of the material of the bowl-shaped portion Flow to the part side becomes easy. Therefore, an increase in tensile stress generated in the bowl-shaped portion can be suppressed, and the shape accuracy of the cylindrical portion can be improved more suitably .
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a workpiece according to an embodiment. FIG. 2 is an explanatory diagram for explaining a process for manufacturing the workpiece of the embodiment. FIG. 3 is an explanatory view for explaining the ironing process of the embodiment.
[0026]
The workpiece 1 is a flanged and stepped cylindrical member, and includes a first cylindrical part 11, a first flanged part 12, a second cylindrical part 13, and a second flanged part 14. The 1st cylindrical part 11 is a substantially cylindrical shape, The one end is bent slightly inside. The outer peripheral surface of the first cylindrical portion 11 has a true cylindrical shape, and the inner peripheral surface is a tapered surface (inclined surface) that widens upward in FIG. The inclination angle R1 of the taper surface is 0.17 degrees. The first hook-like part 12 is an outward hook-like part that is continuous with the other end of the first cylindrical part 11. That is, the first flange 12 has a bent portion 16 at the upper end of the first tubular portion 11, and is continuous with the first tubular portion 11 at the bent portion 16. The second cylindrical portion 13 has a substantially cylindrical shape that is continuous with the first cylindrical portion 11 of the first flange-shaped portion 12 and is continuous with the opposite side of the one end side. The outer peripheral surface of the second cylindrical portion 13 has a true cylindrical shape, and the inner peripheral surface is a tapered surface (inclined surface) that widens upward in FIG. The inclination angle R2 of the tapered surface is also 0.17 degrees. The second hook-shaped portion 14 is an outward hook-shaped portion continuous with one end of the second cylindrical portion 13. That is, the second hook-shaped portion 14 has a bent portion 16 at the upper end of the second cylindrical portion 13, and is continuous with the second cylindrical portion 13 at the bent portion 16. The first hook-shaped part 12 is a stepped part connecting the first cylindrical part 11 and the second cylindrical part 13 having different diameters, but is a hook-like part when viewed from the first cylindrical part 11, and in the present invention. The so-called saddle-shaped portion includes all outward-facing saddle-shaped portions continuous to one end of the cylindrical portion. The material of the workpiece 1 is a rolled steel material SPC280. The material of the workpiece 1 is not limited to this, and a metal material that can be ironed, such as hot-rolled steel SPH280, aluminum, or copper, can be used.
[0027]
The workpiece 1 is manufactured through steps from an upper step to a lower step shown in FIG. A disk-shaped plate material having a thickness of 2.6 mm is prepared in the blanking process. The flanged bottomed cylindrical member 24 is manufactured by drawing from the first drawing step to the third drawing step. A stepped shape is formed by drawing in the fourth drawing step. The taper surfaces of the first cylindrical portion 11 and the second cylindrical portion 13 are formed in the re-striking (relief taper forming) step. The re-striking process is performed by semi-hermetic molding similar to forging generally performed. Finally, the bottom portion 26a is punched out to form the hole portion 15 in the bottom hole piercing step. Thus, the work 1 is completed.
[0028]
The mold will be described with reference to FIG. The punch 40 is provided with a tip portion 41, a first rod-shaped portion 42, a second rod-shaped portion 43, and a base portion 44. The tip portion 41 is a portion that is inserted into the hole portion 15 of the workpiece 1. The first rod-like portion 42 is a portion where one end is continuous with the tip portion 41 and the other end is continuous with the second rod-like portion 43 and is inserted into the first tubular portion 11 of the workpiece 1. The outer peripheral side has a substantially cylindrical shape, but the portion continuing to the second rod-like portion 43 has an R-shaped cross section on the outside. The inner diameter dimension of the first cylindrical portion 11 after ironing is determined by the outer dimension of the first rod-shaped portion 42.
[0029]
The second rod-shaped portion 43 is a portion that is inserted into the second cylindrical portion 13 of the workpiece 1. The surface of the second rod-shaped portion 43 that protrudes from the first rod-shaped portion 42 that is continuous with the first rod-shaped portion 42 is a portion that contacts the upper surface of the first flange-shaped portion 12 of the work 1. The outer peripheral side of the 2nd rod-shaped part 43 is a true cylinder shape. The inner diameter dimension of the second cylindrical portion 13 after ironing is determined by the outer dimension of the second rod-shaped portion 43. The side opposite to the side continuous with the first rod-shaped portion 42 of the second rod-shaped portion 43 is continuous with the base portion 44. The lower surface of the portion that protrudes from the second rod-shaped portion 43 of the base portion 44 is a portion that contacts the upper surface of the second hook-shaped portion 14 of the workpiece 1.
[0030]
The die 30 is provided with a first ironing portion 31 and a second ironing portion 32. The 1st ironing part 31 is a part which irons the 1st cylindrical part 11, and shape | molds the inner-outer diameter. A first convex portion 33 that protrudes toward the first hook-shaped portion 12 is provided on the upper surface of the first ironing portion 31 that faces the lower surface of the first hook-shaped portion 12. The first convex portion 33 has a triangular cross section (substantially isosceles triangle). The first convex portion 33 is provided at the inner peripheral side end of the upper surface of the first ironing portion 31. The 1st convex part 33 is a ring shape which has a circular ridgeline. The outer diameter of the first cylindrical portion 11 after ironing is determined by the inner diameter of the first ironing portion 31. A proper iron introduction angle is provided on the inner diameter side of the first ironing portion 31, and an appropriate R chamfer is formed at the corner portion between the inner diameter surface and the upper surface.
[0031]
The 2nd ironing part 32 is a part which irons the 2nd cylindrical part 13, and shape | molds the inner-outer diameter. On the upper surface of the second ironing portion 32 that faces the lower surface of the second hook-shaped portion 14, a second convex portion 34 that protrudes toward the second hook-shaped portion 14 is provided. Similarly to the first convex portion 33, the second convex portion 34 has a triangular cross section (substantially isosceles triangle), and is provided at the inner peripheral end of the upper surface, and has a circular ridge line (top). Shape. The 1st convex part 33 and the 2nd convex part 34 have the inclined surface 35 ranging from this ridgeline to the corresponding part of the bending part of the inner corner part in the workpiece 1. The outer diameter of the second cylindrical portion 13 after ironing is determined by the inner diameter of the second ironing portion 32. A proper iron introduction angle is provided on the inner diameter side of the second ironing portion 32, and an appropriate R chamfer is formed on the corner portion between the inner diameter surface and the upper surface.
[0032]
Next, the ironing process will be described. First, the workpiece 1 is fitted to the punch 40. Thus, the punch 40 is inserted into the inner peripheral side of the work 1. At this time, the first rod-like portion 42 is almost fitted to the first tubular portion 11, and the second rod-like portion 43 is almost fitted to the second tubular portion 13. Further, the lower surface of the second rod-shaped portion 43 is in contact with the upper surface of the first hook-shaped portion 12, and the lower surface of the base portion 44 is in contact with the upper surface of the second hook-shaped portion 14. At this time, the die 30 exists below the workpiece 1.
[0033]
Subsequently, the punch 40 is lowered while the workpiece 1 is fitted, and inserted into the die 30. As the work 1 is lowered, the first cylindrical portion 11 is ironed by the first ironing portion 31, the second cylindrical portion 13 is ironed by the second ironing portion 32, and the lower surface of the first hook-like portion 12 is the first convex. 3 is in contact with the ridgeline of the portion 33, and the lower surface of the second hook-shaped portion 14 is in contact with the ridgeline of the second convex portion 34, resulting in the state shown in the left diagram of FIG. During the ironing process, the outer diameter of the first cylindrical portion 11 is reduced to the inner diameter of the first ironing portion 31 and the first rod-shaped portion 42 is formed by the tapered surface on the inner peripheral side of the first cylindrical portion 11. The material of the 1st cylindrical part 11 flows into the clearance gap formed between and the inside diameter dimension of the 1st cylindrical part 11 becomes the outside diameter dimension of the 1st rod-shaped part 42. FIG. Further, the outer diameter of the second cylindrical portion 13 is reduced to the inner diameter of the second ironing portion 32, and between the second rod-shaped portion 43 by the tapered surface on the inner peripheral side of the second cylindrical portion 13. When the material of the second cylindrical portion 13 flows into the gap thus formed, the inner diameter dimension of the second cylindrical portion 13 becomes the outer diameter dimension of the second rod-shaped portion 43, and the punch 40 is further lowered, the right figure in FIG. As shown in the drawing on the right side of the center line, the first protrusion 33 enters the first flange 12 and the material of the first flange 12 on the inner peripheral side from the ridge line of the first protrusion 33 is the first. It flows to the cylindrical part 11 side, and the material of the first flange-like part 12 on the outer peripheral side from the ridgeline of the first convex part 33 flows to the second cylindrical part 13 side. At the same time, the second protrusion 34 enters the second flange 14, and the material of the second flange 14 on the inner peripheral side from the ridge line of the second protrusion 34 flows toward the second cylindrical portion 13, The material of the second hook-shaped portion 14 on the outer peripheral side from the ridge line of the two convex portions 34 flows toward the outer peripheral side.
[0034]
When the pressing force of the punch 40 reaches a predetermined pressure or reaches a predetermined position, the lowering of the punch 40 is stopped. After a predetermined time has elapsed after the punch 40 has stopped, the punch 40 is lifted and the workpiece 1 is taken out to complete the product.
[0035]
In this product, since the material of the first hook-like part 12 flows to the first cylindrical part 11 side and the material of the second hook-like part 14 flows to the second cylindrical part 13 side, the first cylinder The outward tensile stress generated in the first hook-like part 12 and the second hook-like part 14 as the diameter is reduced by the ironing of the hook-like part 11 and the second cylindrical part 13 can be relaxed. As a result, the difference in the amount of springback in the axial direction of the first cylindrical portion 11 and the second cylindrical portion 13 can be reduced, and the shape accuracy (cylindricity) of the first cylindrical portion 11 and the second cylindrical portion 13 can be reduced. It can be improved. Since the 1st convex part 33 and the 2nd convex part 34 are provided in the inner peripheral side edge part like an Example, the flow effect of material is heightened.
[0036]
Furthermore, in an Example, a taper surface is formed in the inner peripheral side of the 1st cylindrical part 11 or the 2nd cylindrical part 13, and it is the 1st rod-shaped part, so that it is respectively close to the 1st collar-shaped part 12 or the 2nd collar-shaped part 14. 42 and the second rod-shaped portion 43, there are many gaps, so that the material flow to the first tubular portion 11 side of the first flange-shaped portion 12 and the second tubular portion 13 side of the second flange-shaped portion 14 The material flow can be facilitated, and the shape accuracy (cylindricity) of the first cylindrical portion 11 and the second cylindrical portion 13 can be further improved. In the embodiment, the inclination angle of the tapered surface was 0.17 degrees, but is not limited to this, and can be appropriately selected depending on the product shape, material, and the like. However, the inclination angle of the tapered surface is desirably 0.06 to 0.57 degrees, more desirably 0.14 to 0.29 degrees, and 0.14 to 0.20 degrees.
[0037]
Further, in the embodiment, the portion of the first rod-shaped portion 42 that is continuous with the second rod-shaped portion 43 has an R-shaped cross section on the outside, so that the upper end portion of the first tubular portion 11 and the first rod-shaped portion 42 of the punch 40 are used. There is a gap between them. This clearance can promote the material flow of the first flange-shaped portion 12 toward the first tubular portion 11 and improve the shape accuracy (cylindricity) of the first tubular portion 11.
[0038]
In the embodiment, the first convex portion 33 and the second convex portion 34 cause the material of the first flange portion 12 and the second flange portion 14 to flow toward the first cylindrical portion 11 side and the second cylindrical portion 13 side. However, it may be fluidized by other methods. For example, it can also be made to flow by making the pressure which clamps a bowl-shaped part with a die | dye and a punch into the stress by which a bowl-shaped part plastically deforms. In the case of a product that requires a small amount of material flow, a sufficient effect can be exhibited. In this case, if the surface of the die or punch that comes into contact with the bowl-shaped portion is formed so that the distance between the die and the punch becomes narrower toward the outer periphery, the material can flow more effectively. In the case of a bowl-shaped part that forms a stepped part, such as the first bowl-shaped part 12, the outer peripheral side is constrained by the second ironing part 32 of the die 30, so that the first cylindrical shape is obtained only by the pressure sandwiched between the die and the punch. The effect of causing the material to flow toward the portion 11 side is great.
[0039]
The first convex portion 33 and the second convex portion 34 have a triangular cross-sectional shape, but other cross-sectional shapes can also be used. FIG. 4 is an explanatory diagram for explaining the cross-sectional shapes of various convex portions. FIG. 4A shows a sectional shape (triangular shape) of the embodiment. In FIG. 4B, the cross-sectional shape of the convex portion is a semicircular shape. In FIG. 4C, the convex portion has a trapezoidal cross-sectional shape. Although any convex shape has an inclined surface on the inner peripheral side, the inclined surface may not exist. However, due to the presence of the inclined surface, the material flow to the cylindrical portion side of the bowl-shaped portion can be promoted.
[0040]
The shape and amount of the crushed portion of the hook-shaped portion (the convex portion and the portion crushed by pressure) are properly used depending on the amount of springback that comes from the size of the hook-shaped portion, product shape, material characteristics, and the like. Correspondingly, the cross-sectional shape and size of the convex portion may be set.
[0041]
Although the convex part of an Example is provided in the part facing the bowl-shaped part of a die | dye, it may be provided in the part facing the bowl-shaped part of a punch, and may be provided in both. Both have the same effects as the embodiment. Since the protrusions leave behind the crushed portion in the bowl-shaped portion, it may be appropriately selected according to the needs of the product.
[0042]
In the embodiment, the cylindrical portion has a cylindrical shape, but may have an elliptical cylindrical shape or other cylindrical shapes. Moreover, although the hole part 15 is provided in the Example, a bottomed cylindrical shape may be sufficient and the thing with a plurality of small hole parts formed in the bottom may be sufficient. These shapes are appropriately selected depending on the product shape.
[0043]
In the embodiment, the inclined surface is formed by a tapered surface, but if it is an inclined surface, it does not need to be a tapered surface. The inclined surface does not necessarily have to be continuously inclined. Furthermore, there may be no inclined surface.
[0044]
In this way, in the present invention, a brazed tubular member having a tubular portion with excellent shape accuracy can be manufactured without adding a process such as machining, and therefore can be manufactured at low cost.
[0045]
【The invention's effect】
As described above, the present invention is provided with an ironing process step of ironing the cylindrical portion of the workpiece having a cylindrical portion and an outward flange-like portion continuous with one end of the cylindrical portion with a punch and a die. A molding method characterized by causing the material of the bowl-shaped part to flow toward the cylindrical part at the end of the ironing process, or an outward bowl-like shape continuous to the cylindrical part and one end of the cylindrical part A mold having a punch and a die for ironing the cylindrical portion of the workpiece having a portion, wherein at least one of a portion facing the flange-shaped portion of the punch and a portion facing the flange-shaped portion of the die Therefore, the shape accuracy of the cylindrical portion can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a workpiece according to an embodiment. FIG. 2 is an explanatory view illustrating a process for manufacturing the workpiece according to the embodiment. FIG. 3 is an explanatory view illustrating ironing processing according to the embodiment. Explanatory drawing explaining the cross-sectional shape of the material 【Explanation of symbols】
DESCRIPTION OF SYMBOLS 1 ... Work 11 ... 1st cylindrical part (cylindrical part)
12 ... 1st hook-like part (hook-like part)
13 ... 2nd cylindrical part (cylindrical part)
14 ... 2nd bowl-shaped part (bridge-shaped part)
16 ... Bending part 30 ... Die 33 ... First convex part (convex part)
34 ... 2nd convex part (convex part)
35 ... inclined surface 40 ... punch

Claims

The cylindrical portion of the workpiece having a cylindrical portion and a flange-like portion that has a bent portion at one end of the cylindrical portion and that extends continuously and extends outward is provided at a location corresponding to an inner corner portion of the bent portion. An ironing process step of ironing with a punch and a die provided with a convex portion provided on one side so as to protrude only on the hook-shaped portion side and the top portion thereof is spaced outward from the corresponding portion of the bent portion of the inner corner portion; ,
A drawing process for drawing the shape of the workpiece from a plate member, and a restructuring step for forming the inner peripheral surface of the cylindrical portion of the workpiece into a shape that gradually decreases in diameter as it moves away from the outer corner portion. Provided before the processing step,
After the drawing step, the restructuring step is performed, and then the ironing step is performed on the workpiece having a shape that gradually decreases in diameter as the inner peripheral surface of the cylindrical portion moves away from the outer corner portion, and the convex portion Has an inclined surface from the top portion to the corresponding portion of the bent portion of the inner corner portion, and causes the material of the bowl-shaped portion to flow to the cylindrical portion side by the convex portion at the end of the ironing process. A molding method characterized by the above.

The top of one of the convex portions of the punch or die having the convex portion of the bowl-shaped portion of the workpiece and the portion facing the hook-shaped portion of the other punch or die are in contact with the hook-shaped portion. The end of the ironing process is started from a state in which a gap exists between the outer corner portion side of the bent portion and the other punch or die on the inner peripheral surface of the cylindrical portion. The molding method according to claim 1.