JP3963305B2 - Automotive closed-section structural members - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、自動車用閉断面構造部材及びその製造方法に係り、更に詳細には、閉断面構造部材の曲げ荷重特性を変化させてエネルギー吸収を増加させ、且つ重量増加及びコストの増加を伴わない自動車用閉断面構造部材及びその製造方法に関するものである。
【０００２】
【従来の技術】
従来より、自動車の軽量化技術については、省エネルギー化及び車両の運動性能向上等の観点から重要な課題となっているとともに、車両の安全性向上の要求をも満足するような開発が望まれている。そこで、最近の自動車においては、車体の軽量化とエネルギー吸収の両立という観点から、アルミニウム部材を鋼板構造部の補強材として利用することも検討されている。
【０００３】
これらの技術に関しては、自動車技術会、学術講演会前刷集９７３『鋼及び、アルミ構造部材のエネルギー吸収特性の検討』（１９９７）にアルミニウム押出材を用いた例が示されており、図１２にはエネルギー吸収特性を比較するために用いた３種類の断面構造について示されている。図１２（Ａ）は長手方向に外側フランジ部を有する鋼板製コ字状断面部材と、その開口側に鋼板製クロージングプレートを用いてフランジ部を溶接した構造部材を示したものである。図１２（Ｂ）は、上記タイプ（Ａ）の構造において、コ字状断面部材の内側に更に高強度の厚い板厚の鋼板製コ字状断面部材をレインフォース部材として設け、フランジ部を一体に溶接したものである。また、図１２（Ｃ）は、タイプ（Ａ）の開口側に取付けられるクロージングプレート内側の閉断面構造内部に、更にアルミニウムからなる押出し部材をレインフォースとして取付けた構造を有する部材である。図１４（ａ）は、上述した従来のタイプ（Ａ）、（Ｂ）及び（Ｃ）の構造部材について、図１３に示す静的３点曲げ試験を行った結果を示したものであり、また図１４（ｂ）は、同様の部材について、台車を１５ｋｍ／ｈｒの速度で走行させ押し治具に部材を衝突させたときの動的エネルギー吸収特性を求めたものである。
【０００４】
これらの結果から、コ字状断面部材とその開口側にクロージングプレートを溶接したタイプ（Ａ）の構造部材では、曲げ変形初期にピーク荷重が発生し、変形の後期に従って緩やかに荷重が下がるような荷重−変位線図を示すことが認められる。また、タイプ（Ａ）閉断面構造部材に更に高強度の厚い板厚のコ字状断面部材を内部に挿入したタイプ（Ｂ）構造部材は、曲げ荷重が平均的に増加してピークがより顕著に認められるが、荷重−変位線図の形状特性は同様の傾向を示していることが認められる。
【０００５】
更に、自動車技術会、学術講演前刷集９５１『薄鋼板閉断面ビームの補強と静的曲げ強度特性』（１９９５）に示される図１５（ａ）は、従来より自動車用構造部材として用いられているコ字状断部材同士を、外側フランジとして接合した薄板閉断面構造部材の曲げ変形時の特徴を示したものである。このように従来より用いられている自動車用構造部材にあっては、コ字状断面部材の一方の底面外側より力が加わると、曲げ変形時において両コ字状断部材の底面同士は相互に近づくように内側に変形し、また同時に両フランジ部は外側に遠ざかるような変形モードとなる。この変形を防止するためには、図１５（ｂ）に示すように、両フランジ部を繋ぐレインフォース部材を追加する方法が一般的に用いられており、この効果について比較した結果が図１６である。図１６はレインフォース部材の有無について前述と同様の曲げ試験を実施して得られた荷重−変位線図である。レインフォース部材がない構造部材の荷重−変位線図は変形後期においても荷重低下が抑制されるのが認められる。
【０００６】
このように、従来の自動車用構造部材において、構造部材の曲げ変形特性を変化させるためには、開断面構造部材の内部にレインフォース部材を追加する方法が一般的に行われてきた。
【０００７】
【発明が解決しようとする課題】
しかしながら、上述したように従来の自動車用構造部材において曲げ変形特性を変形させるためにレインフォース部材を追加すると、座屈変形抑制に有効に作用して荷重吸収エネルギー特性は向上するものの、構造部材自体の重量が増加するため車両重量の増加につながってしまうという問題点があった。
また、新たなレインフォース部材を追加する場合には、新たに材料費や型製作費用が必要となるため、車両全体としてのコスト増加を伴うという問題があった。
そこで、自動車用構造部材において新たなレインフォース部材を追加せずに、また、コストを増加せずに曲げ荷重特性を変化させてエネルギー吸収を増加させ、上記の問題点を解決することが課題となっていた。
【０００８】
本発明は、このような従来技術の有する課題に鑑みてなされたものであり、その目的とするところは、曲げ荷重特性を変化させてエネルギー吸収を増加させた自動車用閉断面構造部材及びその製造方法を提供することにある。
【０００９】
【課題を解決するための手段】
本発明者らは、上記課題を解決すべく鋭意研究を重ねた結果、曲げ変形時に接合部が折りたたまれるように変形する接合方法を採用することにより、上記課題が解決されることを見出し、本発明を完成するに至った。
【００１０】
即ち、本発明の自動車用閉断面構造部材は、２つのコ字状断面部材が有するフランジを接合して成る自動車用閉断面構造部材であって、
上記フランジは、該コ字状断面部材のコ字状の両端部且つ長手方向に底面とほぼ水平に延在し、少なくとも一方が該部材の外壁側面から内側方向に設けられた内向きフランジであり、
上記コ字状断面部材の長手方向に対して垂直且つ２つのコ字状断面部材がなす外壁面の長さＤと、長手方向に連続するフランジ接合部の合計長さＣとが、２Ｄ≦Ｃを満たし、
長手方向且つ上記内向きフランジにおいて接合されていない部分の最大長さＥと、長手方向に垂直且つ上記コ字状断面部材の底面から該フランジ接合部までの長さＬとが、Ｅ＜Ｌを満たし、
上記フランジの接合率Ｗ（接合長さ／フランジ長さ×１００％）が、７０／Ｌ＜Ｗ／Ｅを満たし、
上記長さＬが、Ｄ／２≦Ｌ≦７Ｄ／８の範囲にあり、
外壁側面に対向するフランジ接合部を有し、上面側から衝撃を受けることを特徴とする。
【００１１】
また、本発明の自動車用閉断面構造部材の好適形態は、上記合計長さＣが、３Ｄ≦Ｃを満たすことを特徴とする。
【００１２】
更に、本発明の自動車用閉断面構造部材の製造方法は、自動車用閉断面構造部材を製造する方法であって、
上記コ字状断面部材のフランジ同士を溶接又は接着により接合することを特徴とする。
【００１３】
【発明の実施の形態】
以下、本発明の自動車用閉断面構造部材について、詳細に説明する。なお、本明細書においては、主に衝撃を受ける側の面を「上面」、他方の面を「底面」と記載するが、両者に本質的な差異がある訳ではなく、説明の便宜のためであり、両者を相互に交換して記載しても、本発明の範囲に属するのはいうまでもない。
【００１４】
上述の如く、本発明の自動車用閉断面構造部材は、２つのコ字状断面部材が有するフランジを接合して成る。言い換えれば、２つのコ字状断面部材を底面内壁が互いに対向するように接合されて成る自動車用閉断面構造部材である。
ここで、上記フランジは、該コ字状断面部材のコ字状の両端部且つ長手方向に底面とほぼ水平に延在する。また、上記フランジの少なくとも一方は、該部材の外壁側面から内側方向に設けられた内向きフランジとする。
このような構成を有する閉断面構造部材とすることにより、外向きフランジのみを有する構造部材に比べ、曲げ変形中の荷重の低下が小さくなる。また、レインフォース部材を追加することなく変形中のエネルギー吸収量が大きくなるので、車両等の構造部材としてに用いるときは、軽量化により燃費が向上し、省資源により材料費や型製作費が削減され、車両等の全体としてコスト低減が図れる。更に、フランジは断続的な接合で足りるため生産性が向上する。
【００１５】
具体的には、例えば、図１７に示すように、２つのコ字状断面部材から成り、両方のフランジを内向きにして溶接して成る自動車用閉断面構造部材（ａ）、両方のフランジを外向きにして溶接して成る自動車用閉断面構造部材（ｂ）、及びこれらの衝撃３点曲げ試験後の曲がり変形部分より説明できる。即ち、従来例の一例である（ｂ）の部材断面は、曲げ変形時にフランジ接合部が両方とも外側に引かれるように変形するのに対し、本発明の一例である（ａ）の部材断面は、接合部が折りたたまれるような変形を生じているのが認められる。
【００１６】
また、図９に示す本発明の自動車用閉断面構造部材の一例のように、コ字状断面部材の長手方向に対して垂直方向且つ上記２つのコ字状断面部材がなす外壁側面の長さＤ（自動車用閉断面構造部材高さ）と、長手方向に連続するフランジ接合部の合計長さＣとは、２Ｄ≦Ｃの関係を満たす。上記フランジ接合長さＣが２Ｄ未満では、フランジ設置方向が内向きであるか外向きであるかを問わず、また、１箇所の非接合部の長さにも関係なく、曲げ変形中の荷重低下が著しく増大し、自動車用などの構造部材として用いるに適さない。
更に、長手方向且つ上記内向きフランジにおいて接合されていない部分の最大長さＥ（非接合部の長さ）と、長手方向に垂直且つ上記コ字状断面部材の底面から該フランジまでの長さＬ（フランジ設置高さ）とは、Ｅ＜Ｌの関係を満たす。非接合部分の長さＥ≧Ｌであると、自動車用閉断面構造部材の上面側からの荷重入力に対して、下部材に力が十分に伝わらず下部材のエネルギー吸収効果が低くなってしまう。
【００１７】
また、上記フランジの接合位置（フランジ設置高さ）とエネルギー吸収効果との関係を表すグラフを図８（ｂ）に示す。
このグラフにおいて、横軸はフランジの接合位置、縦軸はエネルギー吸収を示しており、グラフ中の縦軸の値が高いほど曲げ変形中の荷重の低下が小さいことを示している。なお、衝撃入力により部材が曲げ変形を受ける場合には、初期に断面が潰れる段階とそれに続く曲がり変形が生じる。
従って、本発明では、曲げ変形の曲げ中心側を外側（上面側）として、フランジ接合部を自動車用閉断面構造部材高さＤの中間よりも外側に配置することにより、自動車用閉断面構造部材にエネルギー吸収効果を与えることができる。なお、最外面、言い換えれば、Ｌ＝Ｄとなる位置で接合すると上記効果は全く得られない。
【００１８】
具体的には、上記フランジ設置高さＬが、Ｄ／２≦Ｌ≦７Ｄ／８の範囲にあるようにする。言い換えれば、自動車用閉断面構造部材の延在方向（長手方向）に垂直である外壁側面の長さＤの中間から、上面側（外側）へ３／４（中間〜上面の３／４の距離）までの範囲であることが良い。
この範囲にフランジ接合部を配置することにより、曲げ変形中の荷重の低下が小さくなり易く、エネルギー吸収量が大きくなり易いので有効である。また、１５％以上の軽量化効果に相当するエネルギー吸収の増加、即ち、かかる位置に内向きフランジ接合部を有することで、従来の自動車用閉断面構造部材（両側に外向きフランジを有する構造部材）に部材重量の１５％以上に相当するレインフォース部材を追加した場合と同様のエネルギー吸収量を得ることができる。
【００１９】
また、上記フランジの接合率Ｗ（接合長さ／フランジ長さ×１００％）は、７０／Ｌ＜Ｗ／Ｅを満たすようにする。これより、接合率Ｗが７０〜１００％の場合には著しい差異はないが、７０％未満の場合には自動車用の閉断面構造部材として特に優れた実用性を発揮するので有効である。なお、上記接合長さを、図９（ｂ）に示す自動車用閉断面構造部材の黒塗り部分に例示する。
【００２０】
次に、上述した本発明の自動車用閉断面構造部材の製造方法について詳細に説明する。
この製造方法では、上記コ字状断面部材のフランジ同士を溶接又は接着により接合して、自動車用閉断面構造部材を得る。例えば、図２に示すように、レーザ溶接により、フランジ同士を接合することができる。
【００２１】
次に、本発明の自動車用閉断面構造部材について詳細に説明する。
この自動車用閉断面構造部材は、上述した本発明の自動車用閉断面構造部材を用い、外壁側面に対向するフランジ接合部を有し、上面側から衝撃を受けることを特徴とする。この場合は、曲げ荷重特性を変化させてエネルギー吸収量を増加させるとともに、軽量化が実現でき車両全体としてのコスト低減が図れる。なお、自動車用閉断面構造部材の形状は適宜所望形状に変形して用いることができる。また、上記フランジ接合部は、衝撃を受ける方向などを考慮して対向する接合部の高さが異なるようにしても良い。
【００２２】
【実施例】
以下、本発明を図面を参照して実施例及び比較例により更に詳細に説明するが、本発明はこれらの実施例に限定されるものではない。
【００２３】
（実施例１及び比較例１）
実施例１として、引張り強度が５９０ＭＰａ、板厚１．８ｍｍの鋼板を用いて、ベント成形によりインナー部材とアウター部材の断面深さ比が２：１となるように、部材の両側に内向きフランジ接合部を有する、図１に示すような、断面形状（ａ）（１００ｍｍ×９０ｍｍ、コーナーＲ＝５ｍｍ）及び長さ９００ｍｍ（ｂ）の閉断面構造部材（自動車用閉断面構造部材）を形成した。なお、コ字状部材として用いたインナー部材及びアウター部材の内角は全て９０°とした。また、フランジの接合は、図２に示す内向きフランジの接合方法により、レーザを用いて溶接長を１００％として連続溶接を行った。
【００２４】
一方、比較例１として、実施例１と同様の鋼板を用い、インナー部材とアウター部材の断面深さ比が２：１となるように、部材の両側に外向きフランジ接合部を有する、図１に示すような、断面形状の長さ９００ｍｍの閉断面構造部材（ｃ）を形成した。このとき、外向きフランジには間隔２５ｍｍでスポット溶接を行った。
なお、実施例１及び比較例１の部材において、部材長手方向に直角方向のフランジ接合部を含む外壁側面の長さＤ及び部材底面からフランジ接合部までの距離Ｌは、それぞれＤ＝１００ｍｍ、Ｌ＝６６ｍｍであり、これを図１に合わせて示す。
【００２５】
得られた実施例１及び比較例１の構造部材について、アウター部材が上になるようにして荷重１１０ｋｇ、速度８．３ｍ／ｓｅｃにて衝撃３点曲げ試験を実施した。この結果を図３に示す。
図３より、比較例１の閉断面構造部材は、曲げ変形中期以降に変形荷重が低下してしまうことがわかる。これに対し、実施例１の閉断面構造部材は、曲げ荷重の低下が緩やかになり、変形中におけるエネルギー吸収率が大きいことが認められる。
【００２６】
（実施例２及び比較例２）
実施例２として、引張り強度が４４０ＭＰａ、板厚１．８ｍｍの鋼板を用いて、インナー部材とアウター部材の断面深さ比が２：１となるように、部材の片側に内向きフランジを設け、図４に示すような断面形状（１００ｍｍ×９０ｍｍ、コーナーＲ＝５ｍｍ）及び長さ９００ｍｍの閉断面構造部材を形成した。なお、コ字状部材として用いたインナー部材及びアウター部材の内角は全て９０°とした。また、内向きフランジ及び外向きフランジの接合は、実施例１と同様の方法で接合した。
【００２７】
一方、比較例２として、実施例２と同様の鋼板を用い、インナー部材とアウター部材の断面深さ比が２：１となるように、部材の両側に外向きフランジを設け、各々の面との角度が９０°となるように長さ９００ｍｍの閉断面構造部材を形成した。なお、フランジは比較例１と同様の方法で接合した。
【００２８】
得られた実施例２及び比較例２の構造部材について、アウター部材が上になるようにして荷重３００ｋｇ、速度８．０ｍ／ｓｅｃにて衝撃３点曲げ試験を実施した。この荷重とストロークの関係を図５に示す。
図５より、実施例２の閉断面構造部材は、発生した変形荷重は変形初期のピークは発生しないものの、次第に荷重が増加し、その後の荷重の低下が緩やかになり、比較例２の閉断面構造部材に比較して吸収エネルギー大きくなっているのが認められる。
【００２９】
（実施例３〜５、比較例３〜５）
実施例３〜５として、引張り強度が４４０ＭＰａ、板厚１．６ｍｍの鋼板を用い、インナー部材とアウター部材の断面深さ比が２：１となるように、また、アウター部材の両コ字状部材の内角θがそれぞれ９０°、９８°及び１０５°となるように、部材の両側に内向きフランジを設け、更に、インナー部材の両コ字状部材の内角が９０°となるように、図６（ａ）に示すような、断面形状（１００ｍｍ×９０ｍｍ、コーナーＲ＝５ｍｍ）及び長さ９００ｍｍの閉断面構造部材をそれぞれ形成した。なお、内向きフランジの接合は、レーザを用いて溶接長を１００％として連続溶接を行った。
【００３０】
一方、比較例３〜５として、実施例３〜５と同様の鋼板を用い、インナー部材とアウター部材の断面深さ比が２：１となるように、また、アウター部材の両コ字状内角がそれぞれ９０°、９８°及び１０５°となるように、部材の両側に外向きフランジを設け、更に、インナー部材の両コ字状部材の内角が９０°となるように、図６（ｂ）に示すような、断面形状の長さ９００ｍｍの閉断面構造部材をそれぞれ形成した。なお、外向きフランジは、実施例１と同様の方法で接合した。
【００３１】
得られた実施例３〜５及び比較例３〜５の閉断面構造部材について、アウター部材が上になるようにして荷重３００ｋｇ、速度８．０ｍ／ｓｅｃにて衝撃３点曲げ試験を実施した。この荷重とストロークの関係を図７に示す。
図７より、アウター部材の両コ字状内角度によって発生する反力の値は異なるものの、内向きフランジを有する実施例３〜５の閉断面構造部材の変形荷重は、荷重のピークが発生しないものの、次第に荷重が増加し荷重の低下が緩やかになり、外向きフランジを有する比較例３〜５の閉断面構造部材に比べて吸収エネルギーが大きくなっているのが認められる。
【００３２】
（実施例６〜９及び比較例６〜８）
実施例６〜９及び比較例６、７として、内向きフランジの接合位置、即ち、底面から内向きフランジ接合部までの距離Ｌを変えたこと以外は、実施例１と同様の操作を繰り返して、閉断面構造部材を形成した。なお、アウター部材とインナー部材のフランジ接合位置は、接合部外壁面長さの中心部の位置、即ちＬ＝Ｄ／２の位置（（２）：実施例６）、中心部から内側に１／６の位置、即ちＬ＝５Ｄ／１２の位置（（１）：比較例６）、中心部から外側にそれぞれ１／４の位置、即ちＬ＝５Ｄ／８の位置（（３）：実施例７）、２／４の位置、即ちＬ＝３Ｄ／４の位置（（４）：実施例８）、及び３／４の位置、即ちＬ＝７Ｄ／８の位置（（５）：実施例９）とした。
また、実施例１と同様の鋼板を用いて、Ｌ＝Ｄ、即ちインナー部材のみを用いてコ字状断面部材の開口部端部に内向きフランジ接合部を有する部材を形成し、その開口部にクロージングプレートを用いてフランジを溶接し、比較例７（（６））の閉断面構造部材を形成した。
更に、アウター部材とインナー部材のフランジを両方とも外側にして接合した以外は、実施例６と同様の操作を繰り返して、比較例８（（７））の閉断面構造部材を形成した。
【００３３】
実施例６〜９及び比較例６〜８で得られた構造部材について、図８（ａ）に示すように、アウター部材（外側）を上にして、衝撃３点曲げ試験を実施した。エネルギー吸収量とフランジの結合位置との関係を図８（ｂ）に示す。
図８（ｂ）において、縦軸は荷重−ストローク線図の面積、即ちエネルギー吸収量を示したもので、エネルギー吸収量が高いほど、曲げ変形中の荷重の低下が小さくエネルギー吸収量のが大きいことを示している。フランジ接合部の位置とエネルギー吸収量の関係では、Ｌ＝３Ｄ／４の位置、即ち部材の外壁側面の中心から外側に１／２の位置において最大のエネルギー吸収が認められる。実施例６〜９の部材は、フランジ接合部の位置が部材外壁側面の長さＤの中心から外側に３／４までの位置（Ｄ／２≦Ｌ≦７Ｄ／８）において、エネルギー吸収量は、外向きフランジを有する従来部材（比較例８）に比較して大きいことがわかる。
実施例６（Ｌ＝Ｄ／２）及び実施例９（Ｌ＝７Ｄ／８）のエネルギー吸収量は、部材重量の約１５％に相当する軽量化の効果が得られることがわかった。即ち、実施例６及び実施例９の部材は、従来の両外向きフランジを有する部材である比較例８（部材重量は実施例６、９と同等）に、部材重量の約１５％に相当する重量のレインフォース部材を追加した部材と同等のエネルギー吸収量が得られる。
また、実施例８（Ｌ＝３Ｄ／４）のエネルギー吸収量は、部材重量の約３０％に相当する軽量化の効果が得られることがわかった。即ち、従来の両外向きフランジを有する部材である比較例８に、部材重量の約３０％に相当する重量のレインフォース部材を追加した部材と同等のエネルギー吸収量が得られる。
【００３４】
（実施例１０〜１３及び比較例９〜１１）
板厚が１．６ｍｍの鋼板を用いた以外は、実施例１と同様の操作を繰り返して、図９に示すような閉断面構造部材を形成した。
また、内向きフランジをそれぞれ、接合率５５％、最大非溶接部長さ２０ｍｍ（実施例１１）、接合率３４％、最大非溶接部長さ３０ｍｍ（実施例１２）、接合率６９％、最大非溶接部長さ５０ｍｍ（実施例１３）とした以外は、実施例１０と同様な操作を繰り返して、実施例１１〜１３の閉断面構造部材を形成した。
【００３５】
一方、内向きフランジをそれぞれ、接合率４７％、最大非溶接部長さ１２５ｍｍ（比較例９）、接合率３２％、最大非溶接部長さ３５ｍｍ（比較例１０）、接合率６９％、最大非溶接部長さ７０ｍｍ（比較例１１）とした以外は、実施例１０と同様の操作を繰り返して、比較例９〜１１の閉断面構造部材を形成した。
【００３６】
実施例１０〜１３及び比較例９〜１１について、衝撃曲げ試験結果の曲げ−平均荷重線図を図１０に示す。図１０では、実施例１０〜１３をＡ群とし、比較例９〜１１をＢ群とした。また、内向きフランジ接合部と接合間隔の有効な範囲の関係を図１１に示す。
図１０及び図１１より、実施例１０〜１３（図１０のＡ群）は、ほぼ同等の衝撃曲げ試験結果が得られ、先述の非溶接長さＥと自動車用閉断面構造部材の底面からフランジまでの長さＬとにおいてＥ＜Ｌであり、且つフランジの接合率（接合長さ／フランジ長さ×１００％）をＷとしたとき、７０／Ｌ＜Ｗ／Ｅの関係を満足していれば、接合率１００％と同等の性能が得られることが認められる。これに対して、比較例９〜１１（図１０のＢ群）は、図１１に示す領域外であり、実施例に比較して曲げ変形中の荷重の低下が大きくエネルギー吸収量が小さいことが認められる。
従って、内向きフランジ接合の場合は図１１に示す範囲が、曲げ変形中の荷重の低下が小さくエネルギー吸収量が大きく効果のある範囲であることがわかる。
【００３７】
以上、本発明を好適実施例及び比較例により詳細に説明したが、本発明はこれら実施例に限定されるものではなく、本発明の要旨の範囲内において種々の変形が可能である。
例えば、上記アウター部材及びインナー部材は、双方を同一材料で形成することに限定されず、エネルギー吸収能を考慮して異種の材料で各部材を形成することもできる。また、外壁側面に対向して存在するフランジ接合部は、必ずしも接合部と接合部とが対向する位置にある必要はない。更に、自動車用閉断面構造部材の上面や底面に所望形状のカバーを取付けたり、上面自体を変形させて更にエネルギー吸収量を高めることもできる。
【００３８】
【発明の効果】
以上説明してきたように、本発明によれば、曲げ変形時に接合部が折りたたまれるように変形する接合方法を採用することとしたため、曲げ荷重特性を変化させてエネルギー吸収を増加させた自動車用閉断面構造部材、その製造方法及び自動車用閉断面構造部材を提供することができる。
【図面の簡単な説明】
【図１】 実施例１及び比較例１で得た自動車用閉断面構造部材の断面形状を示す図である。
【図２】 内向きフランジの接合方法を示す概略図である。
【図３】 実施例１及び比較例１で得た自動車用閉断面構造部材の衝撃３点曲げ試験結果を示すグラフである。
【図４】 実施例２及で得た自動車用閉断面構造部材の断面形状を示す図である。
【図５】 実施例２及び比較例２で得た自動車用閉断面構造部材の衝撃３点曲げ試験結果を示すグラフである。
【図６】 実施例３〜５及び比較例３〜５で得た自動車用閉断面構造部材の断面形状を示す図である。
【図７】 実施例３〜５及び比較例３〜５で得た自動車用閉断面構造部材の衝撃３点曲げ試験結果を示すグラフである。
【図８】 フランジ接合部位置の違いによる衝撃３点曲げ試験結果を示すグラフである。
【図９】 実施例１０で得た自動車用閉断面構造部材の断面形状及び部材形状を示す図である。
【図１０】 実施例１０〜１３及び比較例９〜１１で得た自動車用閉断面構造部材の衝撃３点曲げ試験結果を示すグラフである。
【図１１】 フランジ接合部と接合間隔との有効範囲を示すグラフである。
【図１２】 従来より用いられている自動車用閉断面構造部材の断面形状を示す図である。
【図１３】 静的３点曲げ試験を示す図である。
【図１４】 従来の自動車用閉断面構造部材の３点曲げ試験結果を示す図である。
【図１５】 従来の外向きフランジを有する自動車用閉断面構造部材の曲げ変形時の特徴及びレインフォース部材の追加例を示す図である。
【図１６】 従来の外向きフランジを有する自動車用閉断面構造部材にレインフォース部材を追加した効果を示す図である。
【図１７】 曲がり変形時の断面変形モードを示す概略図である。
【符号の説明】
１ アウター部材
２ インナー部材
３ レーザ溶接ノズル
４ レーザ溶接ビート
５ 内向きフランジ
６ レインフォース部材
７ スポット溶接[0001]
BACKGROUND OF THE INVENTION
The present inventionClosed cross-section structural members for automobiles andAccording to the manufacturing method, more specifically, the bending load characteristic of the closed cross-section structural member is changed to increase the energy absorption, and without increasing the weight and cost.Closed cross-section structural members for automobiles andIt relates to the manufacturing method.
[0002]
[Prior art]
Conventionally, automobile weight reduction technology has been an important issue from the viewpoint of energy saving and improvement of vehicle performance, and development that satisfies the demand for improvement of vehicle safety is desired. Yes. Therefore, in recent automobiles, it has been studied to use an aluminum member as a reinforcing material for the steel plate structure portion from the viewpoint of achieving both weight reduction of the vehicle body and energy absorption.
[0003]
Regarding these technologies, examples of using aluminum extruded materials are shown in the Automotive Engineering Society, Academic Lecture Preprint 973 "Examination of Energy Absorption Characteristics of Steel and Aluminum Structural Members" (1997),FIG.Shows three types of cross-sectional structures used for comparing energy absorption characteristics.FIG.(A) shows the structural member which welded the flange part using the steel plate closing plate on the opening side, and the steel plate U-shaped cross-section member which has an outer side flange part in a longitudinal direction.FIG.(B) is a structure of the above type (A), in which a U-shaped cross-section member made of a steel plate having a higher strength and thickness is provided as a reinforcement member inside the U-shaped cross-section member, and the flange portion is integrally welded. It is a thing. Also,FIG.(C) is a member having a structure in which an extruded member made of aluminum is attached as a reinforcement inside a closed cross-sectional structure inside the closing plate attached to the opening side of type (A).FIG.(A) is the above-mentioned conventional type (A), (B) and (C) structural member,FIG.Shows the results of the static three-point bending test shown in Fig.FIG.(B) shows the dynamic energy absorption characteristics of a similar member when the carriage travels at a speed of 15 km / hr and the member collides with the pushing jig.
[0004]
From these results, in the structural member of the type (A) in which the U-shaped cross-section member and the closing plate are welded to the opening side, a peak load is generated in the early stage of bending deformation, and the load gradually decreases according to the later stage of deformation. It can be seen that a load-displacement diagram is shown. Moreover, the type (B) structural member in which a thicker U-shaped cross-sectional member with higher strength is inserted into the closed sectional structural member of type (A), the bending load increases on average and the peak is more remarkable It can be seen that the shape characteristics of the load-displacement diagram show the same tendency.
[0005]
Furthermore, it is shown in the Automotive Engineering Society, Academic Lecture Preprint 951 “Reinforcement and Static Bending Strength Characteristics of Beams with Closed Sections of Thin Steel Sheet” (1995).FIG.(A) shows the characteristic at the time of bending deformation of the thin-plate closed cross-section structural member which joined the U-shaped cutting member conventionally used as a structural member for motor vehicles as an outer flange. Thus, in the structural member for automobiles conventionally used, when a force is applied from the outside of one bottom surface of the U-shaped cross-section member, the bottom surfaces of both U-shaped cutting members are mutually connected during bending deformation. The deformation mode is such that it is deformed inward so as to approach, and at the same time, both flange portions are moved outward. To prevent this deformation,FIG.As shown in (b), a method of adding a reinforcement member connecting both flange portions is generally used, and the result of comparison of this effect is as follows.FIG.It is.FIG.These are the load-displacement diagrams obtained by implementing the bending test similar to the above about the presence or absence of a reinforcement member. In the load-displacement diagram of the structural member without the reinforcement member, it is recognized that the load decrease is suppressed even in the later stage of deformation.
[0006]
As described above, in order to change the bending deformation characteristics of a structural member in a conventional automotive structural member, a method of adding a reinforcement member inside the open-section structural member has been generally performed.
[0007]
[Problems to be solved by the invention]
However, as described above, when a reinforcement member is added to deform the bending deformation characteristic in the conventional structural member for automobiles, the load absorbing energy characteristic is effectively improved by suppressing buckling deformation, but the structural member itself is improved. This increases the weight of the vehicle, leading to an increase in vehicle weight.
In addition, when a new reinforcement member is added, a new material cost and mold manufacturing cost are required, which causes a problem of an increase in the cost of the entire vehicle.
Therefore, it is a problem to solve the above-mentioned problems by increasing the energy absorption by changing the bending load characteristics without adding a new reinforcement member in the structural member for automobile and without increasing the cost. It was.
[0008]
The present invention has been made in view of such problems of the prior art, and its object is to increase energy absorption by changing the bending load characteristics.Closed cross-section structural members for automobiles andIt is in providing the manufacturing method.
[0009]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by adopting a joining method in which the joint is deformed so as to be folded during bending deformation. The invention has been completed.
[0010]
That is, the present inventionAutomotive closed-section structural membersIsA closed cross-section structural member for automobiles formed by joining flanges of two U-shaped cross-section members,
The flange is an inward flange that extends substantially horizontally from the bottom surface in the longitudinal direction and at both ends of the U-shaped cross-section member, and at least one of the flanges is provided inward from the outer wall side surface of the member. ,
The length D of the outer wall surface perpendicular to the longitudinal direction of the U-shaped cross-section member and formed by the two U-shaped cross-section members and the total length C of the flange joints continuous in the longitudinal direction are 2D ≦ C The filling,
The maximum length E of the portion not joined in the longitudinal direction and the inward flange and the length L perpendicular to the longitudinal direction and from the bottom surface of the U-shaped cross-sectional member to the flange joint portion satisfy E <L. Meet,
The flange joint ratio W (joint length / flange length × 100%) satisfies 70 / L <W / E,
The length L is in the range of D / 2 ≦ L ≦ 7D / 8,
It has a flange joint facing the side of the outer wall and receives impact from the upper surface side..
[0011]
In addition, the present inventionIn a preferred embodiment of the closed cross-section structural member for automobiles, the total length C satisfies 3D ≦ C.It is characterized by that.
[0012]
Furthermore,The method for producing a closed cross-section structural member for automobiles of the present invention is a method for producing a closed cross-section structural member for automobiles,
The flanges of the U-shaped cross-section members are joined together by welding or adhesion.It is characterized by that.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present inventionAutomotive closed-section structural membersWill be described in detail. In this specification, the surface on the impact side is mainly described as “upper surface”, and the other surface is described as “bottom surface”. However, there is no essential difference between the two, and for convenience of explanation. Of course, even if they are described interchangeably, they are within the scope of the present invention.
[0014]
As mentioned above, the present inventionAutomotive closed-section structural membersIs formed by joining flanges of two U-shaped cross-section members. In other words, two U-shaped cross-section members are joined so that the bottom inner walls face each other.Automotive closed-section structural membersIt is.
Here, the flange extends substantially horizontally from the bottom surface in the longitudinal direction and both ends of the U-shaped cross-section member. Further, at least one of the flanges is an inward flange provided inward from the outer wall side surface of the member.
By using the closed cross-section structural member having such a configuration, a decrease in load during bending deformation is reduced as compared with a structural member having only an outward flange. In addition, since the amount of energy absorption during deformation increases without adding a reinforcement member, when it is used as a structural member for a vehicle or the like, fuel consumption is improved by weight reduction, and material costs and mold production costs are reduced due to resource saving. The cost can be reduced as a whole of the vehicle and the like. Furthermore, since the flange is sufficient for intermittent joining, productivity is improved.
[0015]
Specifically, for example,FIG.As shown in Fig. 2, it consists of two U-shaped cross-section members, welded with both flanges facing inwardAutomotive closed-section structural members(A) Made by welding with both flanges facing outwardAutomotive closed-section structural membersThis can be explained from (b) and the bent deformation part after these impact three-point bending tests. That is, the member cross section of (b) which is an example of the conventional example is deformed so that both flange joints are pulled outward during bending deformation, whereas the member cross section of (a) which is an example of the present invention is It can be seen that the joint is deformed so that it is folded.
[0016]
Also,FIG.Of the present invention shown inAutomotive closed-section structural membersAs an example, the length D of the side surface of the outer wall perpendicular to the longitudinal direction of the U-shaped cross-section member and formed by the two U-shaped cross-section members (Automotive closed-section structural members(Height) and the total length C of the flange joints continuous in the longitudinal direction satisfy the relationship of 2D ≦ C. If the flange joint length C is less than 2D, the load during bending deformation regardless of whether the flange installation direction is inward or outward and regardless of the length of one non-joint part The decrease is remarkably increased and is not suitable for use as a structural member for automobiles.
Further, the maximum length E (the length of the non-joined portion) of the portion that is not joined in the longitudinal direction and the inward flange, and the length from the bottom surface of the U-shaped cross-sectional member perpendicular to the longitudinal direction to the flange L (flange installation height) satisfies the relationship E <L. When the length E ≧ L of the non-joined portion,Automotive closed-section structural membersFor the load input from the upper surface side, the force is not sufficiently transmitted to the lower member, and the energy absorption effect of the lower member is lowered.
[0017]
In addition, a graph showing the relationship between the joining position of the flange (flange installation height) and the energy absorption effectFIG.Shown in (b).
In this graph, the horizontal axis indicates the flange joining position, and the vertical axis indicates energy absorption. The higher the value of the vertical axis in the graph, the smaller the decrease in load during bending deformation. In addition, when a member receives bending deformation by impact input, an initial stage in which the cross section is crushed and subsequent bending deformation occur.
Therefore, in the present invention, the bending joint side is defined as the outer side (upper surface side) of the bending deformation.Automotive closed-section structural membersBy placing outside the middle of height D,Automotive closed-section structural membersCan have an energy absorption effect. In addition, if it joins in the outermost surface, in other words, the position where L = D, the above-mentioned effect is not obtained at all.
[0018]
Specifically, the flange installation height L is in the range of D / 2
By disposing the flange joint in this range, it is effective because the decrease in load during bending deformation tends to be small and the amount of energy absorption tends to increase. In addition, an increase in energy absorption corresponding to a weight reduction effect of 15% or more, that is, by having an inward flange joint at this position,Automotive closed-section structural membersIt is possible to obtain the same amount of energy absorption as when a reinforcement member corresponding to 15% or more of the member weight is added to (a structural member having outward flanges on both sides).
[0019]
Further, the joining ratio W (joining length / flange length × 100%) of the flange satisfies 70 / L <W / E.To do. From this, there is no significant difference when the joining ratio W is 70 to 100%, but when it is less than 70%, it is effective because it exhibits particularly excellent practicality as a closed cross-section structural member for automobiles. In addition, the said joining length is set toFIG.Shown in (b)Automotive closed-section structural membersThis is illustrated in the black painted part.
[0020]
Next, according to the present invention described above.Automotive closed-section structural membersThe manufacturing method will be described in detail.
In this manufacturing method, the flanges of the U-shaped cross-section members are joined together by welding or adhesion,Automotive closed-section structural membersGet. For example, as shown in FIG. 2, the flanges can be joined by laser welding.
[0021]
Next, the present inventionAutomotive closed-section structural membersWill be described in detail.
thisAutomotive closed-section structural membersOf the present invention described above.Automotive closed-section structural membersAnd having a flange joint portion facing the side surface of the outer wall and receiving an impact from the upper surface side. In this case, the amount of energy absorption can be increased by changing the bending load characteristics, the weight can be reduced, and the cost of the entire vehicle can be reduced. In addition,Automotive closed-section structural membersThe shape of can be appropriately transformed into a desired shape and used. In addition, the flange joints may have different heights at the opposite joints in consideration of the direction of impact.
[0022]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail with reference to drawings, this invention is not limited to these Examples.
[0023]
(Example 1 and Comparative Example 1)
As Example 1, a steel plate having a tensile strength of 590 MPa and a plate thickness of 1.8 mm is used, and inward flanges are formed on both sides of the member so that the sectional depth ratio of the inner member and the outer member is 2: 1 by vent molding. A closed cross-section structural member (a) (100 mm × 90 mm, corner R = 5 mm) and a length of 900 mm (b) as shown in FIG.Automotive closed-section structural members) Was formed. The inner angles of the inner member and outer member used as the U-shaped member were all 90 °. Further, the flange was joined by continuous welding with a welding length of 100% using a laser by the inward flange joining method shown in FIG.
[0024]
On the other hand, as Comparative Example 1, the same steel plate as in Example 1 was used, and the outer member has outer flange joints on both sides so that the cross-sectional depth ratio of the inner member and outer member is 2: 1. A closed cross-section structural member (c) having a cross-sectional length of 900 mm as shown in FIG. At this time, spot welding was performed on the outward flange at an interval of 25 mm.
In the members of Example 1 and Comparative Example 1, the length D of the outer wall side including the flange joint portion perpendicular to the longitudinal direction of the member and the distance L from the bottom surface of the member to the flange joint portion are D = 100 mm, L = 66 mm, which is shown in FIG.
[0025]
The obtained structural members of Example 1 and Comparative Example 1 were subjected to an impact three-point bending test at a load of 110 kg and a speed of 8.3 m / sec with the outer member facing up. The result is shown in FIG.
From FIG. 3, it can be seen that the deformation load of the closed cross-section structural member of Comparative Example 1 decreases after the middle stage of bending deformation. On the other hand, in the closed cross-section structural member of Example 1, it is recognized that the decrease in bending load is moderate and the energy absorption rate during deformation is large.
[0026]
(Example 2 and Comparative Example 2)
As Example 2, using a steel plate with a tensile strength of 440 MPa and a plate thickness of 1.8 mm, an inward flange is provided on one side of the member so that the cross-sectional depth ratio of the inner member and the outer member is 2: 1, A closed cross-section structural member having a cross-sectional shape (100 mm × 90 mm, corner R = 5 mm) and a length of 900 mm as shown in FIG. 4 was formed. The inner angles of the inner member and outer member used as the U-shaped member were all 90 °. Further, the inward flange and the outward flange were joined in the same manner as in Example 1.
[0027]
On the other hand, as Comparative Example 2, the same steel plate as in Example 2 was used, and outward flanges were provided on both sides of the member so that the cross-sectional depth ratio of the inner member and the outer member was 2: 1. A closed cross-section structural member having a length of 900 mm was formed so that the angle of the angle was 90 °. The flange was joined by the same method as in Comparative Example 1.
[0028]
The structural members of Example 2 and Comparative Example 2 thus obtained were subjected to an impact three-point bending test at a load of 300 kg and a speed of 8.0 m / sec with the outer member facing up. The relationship between this load and stroke is shown in FIG.
From FIG. 5, the closed cross-section structural member of Example 2 shows that the generated deformation load does not generate the initial peak of deformation, but the load gradually increases, and the subsequent decrease in load becomes gradual. It is recognized that the absorbed energy is larger than that of the structural member.
[0029]
(Examples 3-5, Comparative Examples 3-5)
As Examples 3 to 5, a steel sheet having a tensile strength of 440 MPa and a plate thickness of 1.6 mm is used, and the cross-sectional depth ratio of the inner member and the outer member is 2: 1. Inward flanges are provided on both sides of the member so that the inner angle θ of the member is 90 °, 98 ° and 105 °, respectively, and the inner angle of both U-shaped members of the inner member is 90 °. Closed cross-section structural members having a cross-sectional shape (100 mm × 90 mm, corner R = 5 mm) and a length of 900 mm as shown in FIG. The inward flange was joined by continuous welding using a laser at a welding length of 100%.
[0030]
On the other hand, as Comparative Examples 3 to 5, the same steel plates as those of Examples 3 to 5 were used so that the cross-sectional depth ratio of the inner member and the outer member was 2: 1, and the U-shaped inner angle of the outer member was 6 (b), so that outward flanges are provided on both sides of the member such that the inner angles of both inner U-shaped members are 90 °. The closed cross-section structural members having a length of 900 mm as shown in FIG. The outward flange was joined by the same method as in Example 1.
[0031]
For the obtained closed cross-section structural members of Examples 3 to 5 and Comparative Examples 3 to 5, an impact three-point bending test was performed at a load of 300 kg and a speed of 8.0 m / sec with the outer member facing up. The relationship between this load and stroke is shown in FIG.
From FIG. 7, although the value of the reaction force generated varies depending on the both U-shaped inner angles of the outer member, the deformation load of the closed cross-section structural members of Examples 3 to 5 having the inward flange does not generate a load peak. However, it is recognized that the load gradually increases and the decrease in the load becomes gradual, and the absorbed energy is increased as compared with the closed cross-section structural members of Comparative Examples 3 to 5 having the outward flange.
[0032]
(Examples 6-9And Comparative Examples 6-8)
Examples 6-9And as Comparative Examples 6 and 7, the same operation as in Example 1 was repeated except that the joint position of the inward flange, that is, the distance L from the bottom surface to the inward flange joint was changed, and the closed cross-section structural member Formed. Note that the flange joint position between the outer member and the inner member is the position of the center portion of the joint outer wall length, that is, the position of L = D / 2 ((2): Example 6), 1/6 position inward from the center, that is, L = 5D / 12 position ((1): Comparative Example 6), 1/4 position from center to outside, that is, L = 5D / 8 position ((3): Example 7) 2/4 position, ie L = 3D / 4 position ((4): Example 8), And 3/4 position, ie, L = 7D / 8 position ((5): Example 9).
Further, using the same steel plate as in Example 1, L = D, that is, only the inner member is used to form a member having an inward flange joint at the opening end of the U-shaped cross-section member, and the opening A flange was welded using a closing plate to Comparative Example 7 ((6)) Was formed.
Furthermore, the same operation as in Example 6 was repeated except that both the outer member and the flange of the inner member were joined outside, and Comparative Example 8 ((7)) Was formed.
[0033]
Examples 6-9And about the structural member obtained by Comparative Examples 6-8,FIG.As shown in (a), an impact three-point bending test was performed with the outer member (outer side) facing up. The relationship between the amount of energy absorbed and the coupling position of the flangeFIG.Shown in (b).
FIG.In (b), the vertical axis indicates the area of the load-stroke diagram, that is, the amount of energy absorption. The higher the energy absorption amount, the smaller the decrease in load during bending deformation and the greater the amount of energy absorption. Show. As for the relationship between the position of the flange joint and the amount of energy absorption, the maximum energy absorption is recognized at the position of L = 3D / 4, that is, at the position of 1/2 from the center of the outer wall side surface of the member to the outside.Examples 6-9In the case of the member, when the position of the flange joint portion is 3/4 from the center of the length D of the outer wall side surface of the member to the outside (D / 2
Example 6(L = D / 2) andExample 9It has been found that the energy absorption amount of (L = 7D / 8) can provide a weight reduction effect corresponding to about 15% of the weight of the member. That is,Example 6as well asExample 9The member of Comparative Example 8 (member weight is a member having both conventional outward flanges)Examples 6 and 9The same amount of energy absorption as that obtained by adding a reinforcement member having a weight corresponding to about 15% of the weight of the member.
Also,Example 8It has been found that the energy absorption amount of (L = 3D / 4) can provide a weight reduction effect corresponding to about 30% of the member weight. That is, an energy absorption amount equivalent to that obtained by adding a reinforcement member having a weight corresponding to about 30% of the weight of the member to Comparative Example 8 which is a conventional member having both outward flanges can be obtained.
[0034]
(Examples 10-13And Comparative Examples 9-11)
Except for using a steel plate with a plate thickness of 1.6 mm, the same operation as in Example 1 was repeated,FIG.A closed cross-section structural member as shown in FIG.
Each inward flange has a joining rate of 55% and a maximum non-welded part length of 20 mm (Example 11), Joining rate 34%, maximum non-welded part length 30mm (Example 12),
[0035]
On the other hand, each of the inward flanges has a joining rate of 47%, a maximum non-welded portion length of 125 mm (Comparative Example 9), a joining rate of 32%, a maximum non-welded portion length of 35 mm (Comparative Example 10), a joining rate of 69%, and a maximum non-welded portion. Except for the part length of 70 mm (Comparative Example 11),Example 10The same operation was repeated to form closed cross-section structural members of Comparative Examples 9-11.
[0036]
Examples 10-13And about Comparative Examples 9-11, the bending-average load diagram of the impact bending test resultFIG.Shown inFIG.ThenExamples 10-13Was group A, and Comparative Examples 9 to 11 were group B. In addition, the relationship between the inward flange joint and the effective range of the joint intervalFIG.Shown in
FIG.as well asFIG.Than,Examples 10-13(FIG.(Group A) of the above results in almost the same impact bending test results.Automotive closed-section structural membersWhen the length L from the bottom surface to the flange is E <L and the joining ratio of the flange (joining length / flange length × 100%) is W, the relationship of 70 / L <W / E is established. If it is satisfied, it is recognized that a performance equivalent to a joining rate of 100% can be obtained. In contrast, Comparative Examples 9 to 11 (FIG.Group B)FIG.It is recognized that the decrease in load during bending deformation is large and the amount of energy absorption is small compared to the embodiment.
Therefore, in the case of inward flange jointFIG.It can be seen that the range shown in (2) is an effective range in which the decrease in load during bending deformation is small and the amount of energy absorption is large.
[0037]
As mentioned above, although this invention was demonstrated in detail by the preferred Example and the comparative example, this invention is not limited to these Examples, A various deformation | transformation is possible within the range of the summary of this invention.
For example, the outer member and the inner member are not limited to being formed of the same material, and each member can be formed of different materials in consideration of energy absorption capability. Further, the flange joint portion that faces the outer wall side surface does not necessarily have to be in a position where the joint portion and the joint portion face each other. Furthermore,Automotive closed-section structural membersIt is also possible to attach a cover having a desired shape to the upper surface and the bottom surface, or to deform the upper surface itself to further increase the amount of energy absorption.
[0038]
【The invention's effect】
As described above, according to the present invention, since the joining method that deforms so that the joint is folded at the time of bending deformation is adopted, the bending load characteristics are changed to increase energy absorption.Automotive closed-section structural members, Its manufacturing method andAutomotive closed-section structural membersCan be provided.
[Brief description of the drawings]
FIG. 1 obtained in Example 1 and Comparative Example 1Automotive closed-section structural membersIt is a figure which shows no cross-sectional shape.
FIG. 2 is a schematic view showing a method for joining inward flanges.
FIG. 3 obtained in Example 1 and Comparative Example 1Automotive closed-section structural membersIt is a graph which shows an
FIG. 4 obtained in Example 2 and FIG.Automotive closed-section structural membersIt is a figure which shows no cross-sectional shape.
FIG. 5 obtained in Example 2 and Comparative Example 2Automotive closed-section structural membersIt is a graph which shows an
FIG. 6 obtained in Examples 3 to 5 and Comparative Examples 3 to 5Automotive closed-section structural membersIt is a figure which shows no cross-sectional shape.
FIG. 7 obtained in Examples 3 to 5 and Comparative Examples 3 to 5Automotive closed-section structural membersIt is a graph which shows an
[FIG.A graph showing the results of an impact three-point bending test according to the difference in flange joint position.
[FIG.]Example 10Got inAutomotive closed-section structural membersIt is a figure which shows the cross-sectional shape and member shape of this.
[FIG.]Examples 10-13And obtained in Comparative Examples 9-11Automotive closed-section structural membersIt is a graph which shows an
[FIG.A graph showing the effective range of the flange joint and the joint interval.
[FIG.] Conventionally usedAutomotive closed-section structural membersIt is a figure which shows no cross-sectional shape.
[FIG.] A diagram showing a static three-point bending test.
[FIG.】 TraditionalAutomotive closed-section structural membersIt is a figure which shows 3 point | piece bending test result.
[FIG.With conventional outward flangeAutomotive closed-section structural membersIt is a figure which shows the example at the time of bending deformation of, and the additional example of a reinforcement member.
[FIG.With conventional outward flangeAutomotive closed-section structural membersIt is a figure which shows the effect which added the reinforcement member to.
[FIG.A schematic view showing a cross-section deformation mode at the time of bending deformation.
[Explanation of symbols]
1 Outer member
2 Inner material
3 Laser welding nozzle
4 Laser welding beat
5 Inward flange
6 Reinforce materials
7 Spot welding
Claims (3)
上記フランジは、該コ字状断面部材のコ字状の両端部且つ長手方向に底面とほぼ水平に延在し、少なくとも一方が該部材の外壁側面から内側方向に設けられた内向きフランジであり、
上記コ字状断面部材の長手方向に対して垂直且つ２つのコ字状断面部材がなす外壁面の長さＤと、長手方向に連続するフランジ接合部の合計長さＣとが、２Ｄ≦Ｃを満たし、
長手方向且つ上記内向きフランジにおいて接合されていない部分の最大長さＥと、長手方向に垂直且つ上記コ字状断面部材の底面から該フランジ接合部までの長さＬとが、Ｅ＜Ｌを満たし、
上記フランジの接合率Ｗ（接合長さ／フランジ長さ×１００％）が、７０／Ｌ＜Ｗ／Ｅを満たし、
上記長さＬが、Ｄ／２≦Ｌ≦７Ｄ／８の範囲にあり、
外壁側面に対向するフランジ接合部を有し、上面側から衝撃を受けることを特徴とする自動車用閉断面構造部材。A closed cross-section structural member for automobiles formed by joining flanges of two U-shaped cross-section members,
The flange is an inward flange that extends substantially horizontally from the bottom surface in the longitudinal direction and at both ends of the U-shaped cross-section member, and at least one of the flanges is provided inward from the outer wall side surface of the member. ,
The length D of the outer wall surface perpendicular to the longitudinal direction of the U-shaped cross-section member and formed by the two U-shaped cross-section members and the total length C of the flange joints continuous in the longitudinal direction are 2D ≦ C The filling,
The maximum length E of the portion not joined in the longitudinal direction and the inward flange and the length L perpendicular to the longitudinal direction and from the bottom surface of the U-shaped cross-sectional member to the flange joint portion satisfy E <L. Meet,
The flange joint ratio W (joint length / flange length × 100%) satisfies 70 / L <W / E,
The length L is in the range of D / 2 ≦ L ≦ 7D / 8,
A closed cross-section structural member for an automobile having a flange joint facing the side surface of the outer wall and receiving an impact from the upper surface side .
上記コ字状断面部材のフランジ同士を溶接又は接着により接合することを特徴とする自動車用閉断面構造部材の製造方法。A method for producing a closed cross-section structural member for an automobile according to claim 1 or 2,
A method for manufacturing a closed cross-section structural member for an automobile, wherein the flanges of the U-shaped cross-section members are joined together by welding or adhesion.
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| KR101780882B1 (en) * | 2013-04-04 | 2017-09-21 | 신닛테츠스미킨 카부시키카이샤 | Structural member for automobile, and method for manufacturing same |
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| JP4543778B2 (en) * | 2004-06-24 | 2010-09-15 | 住友金属工業株式会社 | Shock absorbing member |
| JP2008055952A (en) * | 2006-08-29 | 2008-03-13 | Tokyu Car Corp | Railroad vehicle truck structure and manufacturing method of the same |
| JP5370652B2 (en) * | 2009-03-31 | 2013-12-18 | マツダ株式会社 | Cabin side structure having a tubular frame disposed at the periphery of the door opening and its assembling method |
| DE102009016220A1 (en) | 2009-04-03 | 2010-10-07 | GM Global Technology Operations, Inc., Detroit | Method for producing a body component of a vehicle and the crankset component of a vehicle |
| JP5609629B2 (en) * | 2010-12-24 | 2014-10-22 | トヨタ紡織株式会社 | Seat frame structure |
| US11623260B2 (en) | 2017-03-15 | 2023-04-11 | Nippon Steel Corporation | Formed body, structural member, and method for producing formed body |
| JP6681941B2 (en) * | 2018-05-31 | 2020-04-15 | 株式会社Uacj | Shock absorber |
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