JP2004051065A

JP2004051065A - Vehicle body structural member and collision-proof reinforcing member

Info

Publication number: JP2004051065A
Application number: JP2002215311A
Authority: JP
Inventors: Koji Fukumoto; 福本　幸司
Original assignee: Kobe Steel Ltd
Current assignee: Kobe Steel Ltd
Priority date: 2002-07-24
Filing date: 2002-07-24
Publication date: 2004-02-19
Anticipated expiration: 2022-07-24
Also published as: JP4015896B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle body structural member and a collision-proof reinforcing member capable of suppressing increase of weight of a hollow structural member and the number of parts to the minimum extent to improve impact absorbing property against vehicle collision. <P>SOLUTION: This vehicle body structural member is constituted in such a way that an aluminum alloy hollow extrusion 6a for reinforcement is extended over the direction of width or the longitudinal direction of the hollow structural member 1a inside the hollow structural member 1a constituted by a formed panel. The hollow extrusion 6a has a curved shape 11 in which a part of the hollow extrusion 6a overhangs toward the direction of vehicle body collision determined for the hollow structural member in the longitudinal direction to constitute an impact absorbing part for vehicle body collision to the hollow structural member by joining with an inner member 3 in both end parts 12a, 12b of the hollow extrusion 6a. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、車体の衝突に対する衝撃吸収性を有している車体構造材および耐衝突補強材に関するものである。
【０００２】
【従来の技術】
周知の通り、自動車の車体を構成する構造材の多くに、近年、基本的な特性である剛性や強度とともに、車体の衝突に対する衝撃吸収性を有していることが求められるようになっている。
【０００３】
これら自動車の車体構造材の内、センターピラー、ドア、サイドシルなど、車体側面側に設置される比較的大型の中空構造部材は、基本的に、鋼やアルミニウム合金、あるいは樹脂などの板をプレス成形されたアウタパネルとインナパネルとを互いに接合し、袋構造乃至中空構造とした成形パネルにより構成される。
【０００４】
近年の自動車の軽量化指向に伴い、これら成形パネルの板厚は、アウタパネルやインナパネルとも、大幅に薄肉化されている。この際、成形パネルに用いられる鋼板やアルミニウム合金板は、ハイテン化　（高強度化）　されている。
【０００５】
しかし、成形パネルの薄肉化は、中空構造部材としての強度、剛性の低下や、衝突時の衝撃吸収性の低下を伴う。したがって、中空構造部材の軽量化と強度、剛性、衝突時の衝撃吸収性などの特性を両立させるためには、中空構造部材全面にわたって存在するパネルの板厚を薄くして軽量化するとともに、中空構造部材の一部に補強部材を設置し、効率的に特性の向上を図るように補強することが重要となっている。このため、従来から、種々の補強構造が提案されている。
【０００６】
図９　〜１３に、これらの補強構造例を自動車中空構造部材の縦方向の断面図で示す。図９　〜１３において、前提となる中空構造部材の構造は同じである。即ち、成形された鋼板製のアウタパネル２　とインナパネル３　とを互いに接合した袋構造からなる。
【０００７】
先ず、図９　の構造部材２０は、アウターパネル２　の内側に補強パネル５ａを接合することで、衝突時の衝撃吸収性能の向上を図っている。ここにおいて、補強による中空構造部材重量の増加をできるだけ抑制するために、これら補強パネル５ａにアルミニウム合金板を、また、後述する中空の補強形材５ｂにはアルミニウム合金押出中空形材などを、各々用いたいという要求がある。ただ、前記図９　の場合では、鋼板製アウタパネルに、素材の異なるアルミニウム補強材を直接接合するような異材接合となり、電食などからくる外観問題あるいは耐食性、水漏れ性などシール性などの問題が生じる。また、このような補強パネル方式では、アルミニウム合金に代えて鋼板のプレス成形品を用いたとしても、重量増加の割には衝突時の衝撃吸収性能が低いという問題がある。
【０００８】
そこで、図１０〜１３において、各図（ａ）　に正面、各図（ｂ）　に平面を各々断面図で示すように、インナパネル側にアルミニウム合金製の耐衝突部材を接合することで、上記問題を解決していることが多い。この耐衝突部材にはアルミニウム合金押出中空形材などが用いられることが多い。
【０００９】
例えば、図１０の構造部材２１は、ドアなどに使用されている構造部材で、インナパネル３　側にブラケット１４を介して中空の補強形材　（耐衝突部材）５ｂ　を支持、接合している。しかし、この図１０の構造では、中空の補強形材５ｂを支持するブラケット１４の部品点数が当然増加するとともに、ブラケット１４に衝突荷重が直接伝わるため、ブラケット１４の強度を比較的高くするため、比較的厚肉化する必要がある。このため、補強効果の割りには、部品点数が増加し、重量増加が大きい。
【００１０】
次に、図１１の構造部材２２では、中空の補強形材５ｂをアウタパネル２　とインナパネル３　の間に設けた、鋼板製パネルからなるセパレータ４ａに支持している。しかし、このセパレータ４ａを構成する鋼板製パネルの重量増加が大きく、中空の補強形材５ｂにアルミニウム材料を適用しても、十分な軽量化効果が得られない。
【００１１】
一方、図１２の構造部材２３のように、直接インナパネル３　に中空の補強形材　５ｂ　を接合する構成では、衝突初期に補強材に荷重が入力されずに変形が進み、所定のエネルギ吸収が得られるストロークが大きくなってしまう。この問題点を解決するために、図１３の構造部材２４のように、より大型の中空断面形状を持つ補強形材５ｂを用いると、この補強形材５ｂの断面積増加による重量増加が大きく、また、ウェブ幅が長くなりすぎることで座屈しやすいなど、結果として所定の衝撃吸収（Ｅ／Ａ）　量および軽量化効果が得られない。
【００１２】
【発明が解決しようとする課題】
このような部品構造が要求される背景には、自動車の安全性の向上の点から、中空構造部材に要求される衝撃吸収性能自体が高く乃至厳しくなるとともに、地球環境への配慮から更なる燃費向上−軽量化−要求が強くなっていることがあげられる。しかし、上記した従来の補強構造では、このように高度化する軽量化および耐衝突性能向上要求の双方を満足することが益々困難になってきている。
【００１３】
これに対し、特にセンターピラーなど比較的大型の形材では、少しでも耐衝突部材への衝撃荷重の入力を早めるべく、重量増加量が最小限となる比較的小さな断面形状を持つ補強部材を、セパレータを介して車体外側に配置するような構造も考案されている。しかし、セパレータの重量増加が非常に大きく、中空構造部材の衝撃吸収性を向上させるためには大きな限界があった。
【００１４】
このため、衝突時のエネルギ吸収性能を効率よく発揮し、かつ、部品点数の増加や重量増加をできるだけ避けた上で、衝撃吸収性能を発揮する車体構造材（　車体部品）　が求められていた。
【００１５】
したがって、本発明の目的は、中空構造部材の重量や部品点数の増加を最小限に抑えて、車体衝突に対する衝撃吸収性を向上させた車体構造材および耐衝突補強材を提供しようとするものである。
【００１６】
【課題を解決するための手段】
この目的を達成するために、本発明車体構造材の要旨は、成形パネルにより構成された中空構造部材内部に、この中空構造部材の幅方向または長手方向に渡って、補強用アルミニウム合金中空形材を延在させた車体構造材であって、前記アルミニウム合金中空形材が、中空構造部材に対して定まる車体衝突方向に向かって中空形材の一部が張り出す湾曲形状を長手方向に渡って有し、このアルミニウム合金中空形材の両端部で中空構造部材と接合されて、中空構造部材への車体衝突に対する衝撃吸収部を構成したことである。
【００１７】
また、本発明耐衝突補強材の要旨は、上記車体構造材に用いられる補強用アルミニウム合金中空形材であって、中空形材の一部が張り出す湾曲形状を長手方向に渡って有したことである。
【００１８】
【発明の実施の形態】
以下、本発明の車体構造材および補強用アルミニウム合金中空形材の実施の形態について図面を用いて詳述する。
【００１９】
図１　は本発明の補強用アルミニウム合金中空形材の１　実施態様を示す斜視図、図２　はこの中空形材を中空構造部材内部に取り付けた車体構造材の１　実施態様を示す平面断面図　（図３　のＢ−Ｂ　線断面図）　、図３　は図２　のＡ−Ａ　線断面図である。
【００２０】
図１　において、先ず、本発明の耐衝突補強材としての補強用アルミニウム合金中空形材６ａは、中空形材の一部である中央部１１が外方　（車体衝突方向、矢印Ｆ）に張り出す、例えば円弧状の湾曲形状を長手方向に渡って有する一方、中空形材の両端部１２ａ　、１２ｂ　において、中空構造部材の例えばインナー部材などとの接合部を有する。
【００２１】
この中空形材６ａの断面は、縦方向の直線状の前面フランジ　（前面縦壁部）７と、前面フランジ７　に略直交し、略水平方向に後面側より前面フランジ７　を支持する２つの直線状のウエブ９　、１０と、ウエブ９　、１０に略直交する直線状の後面フランジ　（後面壁部）８とを有する。なお、前面乃至後面とは、車体衝突方向　（矢印Ｆ）に対する位置関係で表している。そして、前面フランジ７　と後面フランジ８　とは、ウエブ９　と１０による幅以上に縦方向に張り出した張出フランジ７ａ、７ｂと８ａ、８ｂとを各々有する。
【００２２】
次に、図２　、３　において、本発明の車体構造材は、図２　の水平方向の位置関係において、図１　のアルミニウム合金中空形材６ａは湾曲形状を有し、中空構造部材１ａに対して定まる車体衝突方向　（矢印Ｆ　、図の上方、中空構造部材の外方）　に張り出した中空形材の中央部１１を向けて、中空構造部材１ａの中空空間１３内に配置されている。また、中空形材の中央部１１の張出高さ　（張出量）　が、鋼板製のアウタパネル２　から所定のクリアランス（施工上の問題で定まる）を設けた位置まで張り出した形状としている。
【００２３】
更に、図３　の縦方向の位置関係において、中空形材６ａの前面フランジ７　と後面フランジ８　とが略垂直になるように　（ウエブ９　、１０が略水平になるように）　中空構造部材１ａの中空空間１３内に配置されている。
【００２４】
そして、アルミニウム合金中空形材６ａは、図２　の通り、両端部１２ａ　、１２ｂ　において、中空構造部材１ａの鋼板製インナパネル３　側の縦壁３ａと、直接（あるいは耐腐食性の観点からブラケット等を介して）、溶接接合あるいはボルトなどの機械的接合等、汎用されている適宜の接合手段により、剛結合乃至固着され、車体乃至車体構造体と剛結合されている。この中空形材６ａの両端部１２ａ　、１２ｂ　での、車体乃至車体構造体との剛結合は、衝突時に十分な反力の発生を保証する意味からも重要である。通常の車体構造体において、これら補強用中空形材　（耐衝突部材）　は、その機能発揮と中空構造部材の構造からして、中空構造部材の背面を構成する前記インナパネル　（インナ部材）　と結合されることが好ましい。但し、その機能が発揮できるのであれば、中空構造部材の構造に応じて、中空構造部材のアウタなどとも結合されて良い。
【００２５】
一方、本発明では、前記中空形材中央部１１の部分などの張出部の方は、アウタパネルに剛結合乃至固着する必要は無い。
【００２６】
以下、この本発明アルミニウム合金中空形材６ａのエネルギー吸収量向上効果の機構について説明する。今、アルミニウム合金中空形材６ａに対し、アウタパネル２　の頭部２ａを介して、矢印Ｆ　の方向から、衝突などによる荷重　（外力）　がかかった当初、本発明アルミニウム合金中空形材６ａは車体衝突方向　（矢印Ｆ）に対して張り出した湾曲形状を有している　（円弧状中央部１１を有している）　ので、衝突荷重に対して、張り出した中央部１１が、時間的な遅滞なく、いち早く衝突荷重のエネルギー吸収を行うことができる。
【００２７】
なお、前記中空形材中央部１１などの外方に張り出させる張出部の湾曲形状は、上記時間的な遅滞なく衝突荷重のエネルギー吸収を行える張出部形状であれば、必ずしも円弧状でなくても良い。例えば、四角状、台形状などの角張った凸状張出部形状や、先端に凹部などを有する略円弧状の張出部形状を設けて、前記補強用の中空形材を湾曲させたような形状が適宜選択される。ただ、後述する通り、衝突荷重による中空形材長手方向の曲げ座屈を防ぎ、エネルギー吸収量を増すためには、張出部形状は上記円弧状などの曲線的な張出部形状とすることが好ましい。また、同様に、中空形材の外方に張り出させる位置　（張出部を設ける部分）　も、適用する構造部材のエネルギー吸収必要部位によって適宜選択される。即ち、必ずしも中央部１　箇所でなくても、中空形材のいずれか長手方向端部側に偏った部位や、中空形材長手方向の複数箇所を外方に張り出し、湾曲形状を中空形材長手方向に渡って複数箇所、同じ形状乃至異なった形状の張出部を存在させるようにしても良い。
【００２８】
これに対して、直線状の中空形材を補強材５ｂとして用いた従来構造部品（図１０）では、衝突初期にはアウタパネル２　の変形でしかエネルギー吸収手段が無く、本発明構造に比較して、特に衝突初期のエネルギ吸収量に差異が生じることとなる。また、アウターパネルに直接補強板５ａを接合した構造（図９）では、衝突中期にアウターパネルおよび補強板５ａの座屈が生じ、これによるエネルギ吸収量の低下が生じる。
【００２９】
更に、本発明構造では、アルミニウム合金中空形材６ａの長手方向に渡る形状あるいは張出形状を円弧状（アーチ型）の湾曲形状としていることで、上記した通り、衝突荷重に対する曲げ座屈が生じにくいという利点もある。アルミニウム合金中空形材が、従来のような直線状であった場合、曲げ変形時の圧縮荷重は、圧縮側フランジ７　だけで分担され、初期の荷重が負荷された際、圧縮側フランジ７　の中央部で、圧縮側フランジ７　のみの局部的な座屈が生じやすい。圧縮側フランジ７　にこのような局部的な座屈が生じた場合、圧縮側フランジ７　は、それ以降の圧縮応力を負担する能力が低下し、エネルギー吸収量は大幅に低下してしまうからである。
【００３０】
また、従来のような直線状アルミニウム合金中空形材の場合、圧縮側フランジ７　が局部的に座屈すると、これに加えて、それ以降の曲げ変形の進行によって、圧縮側フランジ７　とウエブ９　、１０のつぶれ変形　（中央部での局部的な座屈）　が生じる。このつぶれ変形が生じた場合、引張側フランジ８　の引張応力も、それ以降増加せず、更なる耐曲げ荷重の低下が生じ、エネルギー吸収量はより大幅に低下してしまう。
【００３１】
したがって、前記した、本発明アルミニウム合金中空形材６ａの中央部１１が車体衝突方向に円弧状に張り出すことで、圧縮側フランジ７　が局部的に座屈しないことの、エネルギー吸収量向上に対する意義は大きい。また、この効果は、中空形材６ａの中央部１１の中心部に荷重された場合のみではなく、中央部１１の中心部以外の円弧状張出部に負荷された場合にも発揮される。これは、前記した円弧状以外の形状の張出部でも同様に発揮される。したがって、実際に起こりうる、衝突荷重作用点の張出部中心部からのズレを大きくカバーできる点が本発明の利点でもある。
【００３２】
また、本構造は、単純に補強材をインナーパネルに接合するだけでも十分な効果を発揮するが、特に補強材の接合部をクロスメンバーとの接合部に一致させ、荷重をクロスメンバー側に逃がすような構造とすれば、さらにエネルギ吸収量を大きくすることも可能である。
【００３３】
アルミニウム合金中空形材６ａの例えば中央部１１などの張出部の張出量　（張出高さ）　は、中空構造部材１ａが用いられる車体構造部材毎に、想定される車体衝突荷重量や、要求乃至必要エネルギー吸収量は異なるので、これと、中空構造部材１ａの中空空間１３の大きさ　（中空構造部材１ａの長さあるいは幅）　により、適宜設計される。中空構造部材１ａの中空空間１３の大きさが大きければ、中空形材６ａの中央部１１　などの張出部の張出量を大きく取ることができる。
【００３４】
ピラー、ドア、サイドシルなどの、車体衝突が車体両サイド側から生じる側突に対応した車体構造材は、前記中空空間が大きく取れ、かつ、乗員保護のために大きなエネルギ吸収が必要なことから、本発明の適用が望まれる。なお、ドア、サイドシルでは、これらの中空空間内の衝突　（側突）　対応位置に、アルミニウム合金中空形材６ａを略水平方向に延在させ、中央部１１の張出方向も略水平方向に張り出す。これに対して、縦方向の部材であるピラーなどでは、これらの中空空間内の衝突　（側突）　対応位置に、アルミニウム合金中空形材６ａを略垂直方向に延在させ、張出部１１の張出方向を略水平方向に張り出すことになる。
【００３５】
また、センターピラーでは、側面衝突時に荷重が加わることが多い車体バンパーの高さ付近に張り出し部を設けることが最も有効であり、センターピラーあるいはドア構造では、最も変形が生じやすい中央部に張り出し部を設けることが有効である。
【００３６】
なお、中空形材６ａにおける円弧状などの張出部や湾曲形状の長手方向の長さや曲率の大きさも、前記した、中空形材６ａの中央部１１の張出量の設計基準と同様である。また、接合部１２ａ　、１２ｂ　の長さや面積、あるいは接合手段も適宜設計される。
【００３７】
本発明では、特に図３　から分かる通り、鋼板製のアウタパネル２ａとインナパネル３ａとを仕切る、従来の鋼板製補強セパレータ　（図９　、９　、１０におけるセパレータ２４ａ）が不要である。言い換えると、従来の鋼板製補強セパレータを設けずとも、エネルギー吸収量を大きくすることができる。したがって、この分、構造部材を軽量化でき、補強形材による重量増加を最小化できる効果を有する。
【００３８】
以下に、補強アルミニウム合金中空形材の断面形状について説明する。図１　の中空形材６ａは、前面フランジ７　が、前面フランジ７　に略直交するウエブ９　、１０により、略水平方向に後面側より支持されるため、車体衝突によって、前面フランジ７　に　Ｆの方向から衝撃が加わった場合でも、構造体としての剛性が大きくなり、座屈しにくくなる。この結果、比較的大きな衝突荷重であっても、前面フランジ７　などの折れ曲りや座屈を防止し、衝突荷重のエネルギー吸収量を大きくすることができる。なお、中空形材の断面形状は、重量増加を最小限に抑える観点も加えて、適宜選択される。
【００３９】
また、図１　の中空形材６ａの前面フランジ７　と後面フランジ８　とは、前記張出フランジ７ａ、７ｂと８ａ、８ｂとを各々有することで、前面フランジ７　と後面フランジ８　とは、充分な壁面積と衝突荷重方向をもって、車体衝突に応対することができる。即ち、車体衝突によって、前面フランジ７　に　Ｆの方向から衝撃が加わった場合でも、前面フランジ７　の曲げ剛性が大きくなり、圧壊乃至損壊を防止できるとともに、前面フランジ７　を含めた中空形材６ａ全体が衝突方向（　図の横方向）　に変形して、衝撃荷重を吸収する点で好ましい。
【００４０】
また、後面フランジ８　の張出フランジ８ａ、８ｂの部分で、後述するように、中空構造部材のインナパネル側と溶接あるいはボルトなどの機械的が接合ができ、接合性や接合作業性の点からも好ましい。
【００４１】
なお、前面フランジ７　と後面フランジ８　、あるいはウエブ９　と１０は、直線状でなくとも、外側や内側に膨らむ円弧状などの、曲線的であっても良い。また、その表面も平坦でなくとも、凹凸を設けても良い。
【００４２】
また、本発明の場合、軽量化のためのアルミニウム合金材採用の利点なり目的を達成するためには、肉厚が５ｍｍ　以下の比較的薄い補強用アルミニウム合金中空形材からなることが好ましい。肉厚が５ｍｍ　を越えた場合、重量と強度との関係からは、鋼材と大差なくなり、軽量化のためのアルミニウム合金材採用の利点そのものが損なわれてしまう。言い換えると、本発明の補強用アルミニウム合金中空形材では、肉厚が５ｍｍ　以下の薄いものでも、車体衝突時の衝撃吸収効果を高めることが可能である利点がある。また、このためには、使用するアルミニウム合金材の０．２％耐力が２００ＭＰａ以上の高強度であることが好ましい。
【００４３】
これらの要求特性を満足するアルミニウム合金材としては、通常、この種構造部材用途に汎用される、ＡＡ乃至ＪＩＳ　規格に規定された３０００系、５０００系、６０００系、７０００系等の汎用　（規格）　アルミニウム合金材　（圧延板材、押出形材で、Ｏ　、Ｔ４、Ｔ６、Ｔ７等の要求性能に見合った調質をされたもの）　が好適かつ選択的に用いられる。その中でも、成形性が良く、耐力の比較的高い６０００系、７０００系等のアルミニウム合金材が好ましい。
【００４４】
本発明アルミニウム合金中空形材自体は、これらの条件を満足した上で、押出加工や、圧延板を成形加工および溶接接合するなどの、常法にて製造された直線状の中空形材を製造できる。そして、曲げ加工などにより、中空形材の中央部などの一部を円弧状とするなど、中空形材の長手方向に適宜の湾曲形状を形成することが可能である。
【００４５】
【実施例】
以下に、本発明の実施例を説明する。
図２　、図３　の発明例の車体構造材　（センターピラーを模擬）　を、図６（ｂ）に断面図で示すように、モデル化した。これの基本となるモデルは、アウタ２　とインナ３　とからなる鋼板製成形パネル図６（ａ）である。そして、この基本モデルの断面積（ｍｍ^２）に対し、補強材６ａ　（アルミニウム合金中空形材）　の断面積（ｍｍ^２）　と肉厚（ｍｍ）を変えた場合の、車体構造材の荷重−変位関係、車体構造材重量、エネルギー吸収量　（Ｅ／Ａ　量、変位量１５０ｍｍ　時）　、最大荷重、を各々求めた。
【００４６】
比較として、図９　、１０の従来の車体構造材とを、各々図６（ｃ）、（ｄ）　に断面図で示すようにモデル化したものの車体構造材の荷重−変位関係、エネルギー吸収量（Ｅ／Ａ　量、変位量１５０ｍｍ　時）　、最大荷重、を各々求めた。これらの結果を、表１　、図７　に示す。
【００４７】
ここで、比較例の図６（ｃ）、（ｄ）　のモデルは、図６（ａ）のアウタ２　とインナ３　とからなる車体中空構造部材に、前記図９　、１０と同様に、各々アルミニウム合金製の補強板５ａなり補強材５ｂを取り付けたものである。発明例の図６（ｂ）は、図６（ａ）の車体中空構造部材に図２（図３）の発明例のように、中央部が張出し、湾曲した補強材６ａを中空構造部材内に設けたものである。また、表１　に示す参考例は、上記図６（ｃ）のように、９８０Ｎ級高張力鋼板の補強パネル５ａをアウター２　の裏面に直接接合したものである。
【００４８】
なお、補強用のアルミニウム合金中空形材の０．２％耐力は３００ＭＰａとした。また、曲げ荷重の負荷は、図８　に示すΦ２００ｍｍ　の円筒工具を用い、長さ１２００ｍｍの車体構造材　（アウタ２）の一部　（左端から４００ｍｍ　、右端から８００ｍｍ　の位置）　に、静的に押しつける条件で行った。この解析は　３点曲げの解析モデルを用い、汎用の動的陽解法ソフトＬＳ−ＤＹＮＡ３Ｄ　を用いて行った。
【００４９】
表１　には、解析前提条件として、鋼板製成形パネル　（アウタ２　とインナ３　との合計）　断面積　（ｍｍ^２）、アルミニウム合金中空形材の断面積（ｍｍ^２）　と肉厚（ｍｍ）、車体構造材全体重量（ｋｇ／ｍ）を示す。そして解析結果から得られたエネルギー吸収量（ｋＮ−ｍ、但し変位量３００ｍｍ　時）　、車体構造材全体重量（ｂ）　とエネルギー吸収量（ａ）　との比（ａ／ｂ）　を示す。また、図７　に、車体構造材の荷重−変位関係を示す。
【００５０】
表１　から明らかな通り、図２　のタイプの発明例２　、３　の車体構造材は、比較例４　、５　に比して、エネルギー吸収量と車体構造材重量との比（ａ／ｂ）　が高く、従来の同じ断面形状で直線状押出形材を使用するよりもエネルギー吸収量を大きくできることが分かる。また、高強度な９８０Ｎ級高張力鋼板の補強パネルをアウターに直接接合した構造である参考例に比べても、Ｅ／Ａ　量が大きく、かつ大幅な軽量化が可能であることが分かる。
【００５１】
図７　の荷重−変位関係において、図２　のタイプの発明例２　の車体構造材は、比較例４　、５　に比して、荷重変位曲線の衝突初期の立ち上がり時のピークもなく、その後も緩やかに増加する理想的な荷重変位曲線を示し、エネルギー吸収量が大きい。このことは、大きな曲げ荷重が掛かる初期であっても、発明例の中空形材では、圧縮側フランジの局部的な座屈が生じず、形材全体での曲げ変形による継続的で大きなエネルギー吸収が行われることを表わしている。
【００５２】
これに対し、図７　において、比較例５　では、荷重変位曲線の立ち上がり時のピークが高く、衝突後期において荷重が低下している。これは、アウターおよび補強材がともに座屈し、断面のつぶれ変形による荷重低下が生じたことを示している。また、比較例４　では、衝突初期に補強材が被衝突部材と接触しないことで、衝突初期の荷重の立ち上がりが遅れ、その分、エネルギ吸収量が低下してしまっている。この荷重の立ち上がりの遅れは、対象となる中空構造部材の中空領域が大きくなるほど顕著になることは明白である。つまり、本発明は、中空領域が大きい耐衝突部材ほど、その効果が大きくなると言える。
【００５３】
【表１】

【００５４】
【発明の効果】
本発明によれば、中空構造部材の重量増加を最小限に抑えて、車体衝突に対する衝撃吸収性を向上させた車体構造材および補強用アルミニウム合金中空形材を提供することができる。本発明はこのような優れた効果を有するので、ピラー、ドア、サイドシルなど、車体衝突が車体両サイド側から生じる側突に対応した車体構造材への採用が適している。
このため、自動車の軽量化に大きく寄与するとともに、車体構造材へのＡｌ合金材の用途も大きく拡大するものであり、工業的な価値が高い。
また、自動車車体の衝撃吸収性や衝突安全性が充分機能乃至確保される効果もあり、大きな社会的意義を持つ。
【図面の簡単な説明】
【図１】本発明補強用アルミニウム合金中空形材の一実施態様を示す斜視図である。
【図２】本発明車体構造材の一実施態様を示す平面断面図である。
【図３】図２のＡ−Ａ　断面図である。
【図４】本発明車体構造材の他の実施態様を示す断面図である。
【図５】本発明車体構造材の他の実施態様を示す断面図である。
【図６】本発明車体構造材の解析モデルの態様を示し、図６（ａ）は基本形、図６（ｂ）は比較例、図６（ｃ）は発明例、図６（ｄ）は比較例を各々示す、断面図である。
【図７】本発明車体構造材の荷重−変位曲線を示す説明図である。
【図８】本発明車体構造材の衝撃吸収性能解析の際の試験条件を示す説明図である。
【図９】従来の車体構造材の正面断面図である。
【図１０】従来の車体構造材を示し、（ａ）　は正面断面図、（ｂ）　は平面断面図である。
【図１１】従来の車体構造材を示し、（ａ）　は正面断面図、（ｂ）　は平面断面図である。
【図１２】従来の車体構造材を示し、（ａ）　は正面断面図、（ｂ）　は平面断面図である。
【図１３】従来の車体構造材を示し、（ａ）　は正面断面図、（ｂ）　は平面断面図である。
【符号の説明】
１：車体構造材、２：アウタパネル、３：インナパネル、４：セパレータ
５：補強材、６：補強アルミニウム合金中空形材、７　、８：フランジ、
９　、１０：　ウエブ、１１：　円弧状湾曲　（張出）　部、１２、端部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle body structural material and a collision-resistant reinforcing material having a shock absorbing property against a vehicle body collision.
[0002]
[Prior art]
As is well known, in recent years, many structural materials constituting a vehicle body have been required to have a shock absorbing property against a collision of the vehicle body, in addition to rigidity and strength, which are basic characteristics. .
[0003]
Among these car body structural materials, relatively large hollow structural members installed on the side of the car body, such as center pillars, doors, and side sills, are basically press-formed from steel, aluminum alloy, or resin. The outer panel and the inner panel are joined to each other, and are formed by a molded panel having a bag structure or a hollow structure.
[0004]
With the recent trend toward reducing the weight of automobiles, the thickness of these molded panels, both outer panels and inner panels, has been greatly reduced. At this time, the steel sheet and the aluminum alloy sheet used for the molded panel are made to have a high tensile strength (high strength).
[0005]
However, the reduction in the thickness of the molded panel is accompanied by a decrease in strength and rigidity of the hollow structural member and a decrease in shock absorption at the time of collision. Therefore, in order to achieve the characteristics of the hollow structural member such as weight reduction and strength, rigidity, and shock absorption at the time of collision, the thickness of the panel existing over the entire surface of the hollow structural member is reduced by reducing the thickness of the hollow structural member. It is important to install a reinforcing member in a part of the structural member and to reinforce the member so as to efficiently improve the characteristics. For this reason, various reinforcement structures have been conventionally proposed.
[0006]
FIGS. 9 to 13 show examples of these reinforcing structures in a longitudinal sectional view of a hollow structural member of an automobile. 9 to 13, the premise of the hollow structural member is the same. That is, it has a bag structure in which the formed outer panel 2 and inner panel 3 made of steel plate are joined to each other.
[0007]
First, in the structural member 20 shown in FIG. 9, the reinforcing panel 5a is joined to the inner side of the outer panel 2 to improve the shock absorbing performance at the time of collision. Here, in order to suppress the increase in the weight of the hollow structural member due to reinforcement as much as possible, an aluminum alloy plate is used for these reinforcing panels 5a, and an aluminum alloy extruded hollow shape is used for the hollow reinforcing members 5b to be described later. There is a demand to use it. However, in the case of FIG. 9 described above, the dissimilar material joining is performed such that an aluminum reinforcing material of a different material is directly joined to the outer panel made of a steel plate, and there are problems such as appearance problems due to electrolytic corrosion and sealing properties such as corrosion resistance and water leakage. Occurs. Further, in such a reinforcing panel system, even if a press-formed product of a steel plate is used instead of the aluminum alloy, there is a problem that the impact absorption performance at the time of collision is low in spite of the increase in weight.
[0008]
Therefore, in FIG. 10 to FIG. 13, a collision-resistant member made of an aluminum alloy is joined to the inner panel side as shown in a front view in each figure (a) and a sectional view in each figure (b). Often solving problems. For this collision-resistant member, an aluminum alloy extruded hollow profile or the like is often used.
[0009]
For example, a structural member 21 shown in FIG. 10 is a structural member used for a door or the like, and supports and joins a hollow reinforcing member (collision-resistant member) 5 b to the inner panel 3 via a bracket 14. However, in the structure of FIG. 10, the number of parts of the bracket 14 supporting the hollow reinforcing member 5b naturally increases, and the collision load is directly transmitted to the bracket 14, so that the strength of the bracket 14 is relatively increased. It needs to be relatively thick. For this reason, the number of parts increases and the weight increase is large in spite of the reinforcing effect.
[0010]
Next, in the structural member 22 shown in FIG. 11, the hollow reinforcing member 5b is supported by the separator 4a made of a steel plate and provided between the outer panel 2 and the inner panel 3. However, the weight increase of the steel plate panel constituting the separator 4a is large, and even if an aluminum material is applied to the hollow reinforcing member 5b, a sufficient weight reduction effect cannot be obtained.
[0011]
On the other hand, in a configuration in which the hollow reinforcing member 5b is directly joined to the inner panel 3 as in the structural member 23 in FIG. 12, the deformation proceeds without inputting a load to the reinforcing member in the initial stage of the collision, and a predetermined energy absorption is achieved. The resulting stroke will be large. In order to solve this problem, when a reinforcing member 5b having a larger hollow cross-sectional shape is used as in the structural member 24 in FIG. 13, the weight increase due to the increase in the cross-sectional area of the reinforcing member 5b is large. Further, the web width becomes too long, and the web tends to buckle. As a result, a predetermined impact absorption (E / A) amount and a weight reduction effect cannot be obtained.
[0012]
[Problems to be solved by the invention]
Behind the demand for such a component structure, the impact absorption performance itself required for the hollow structural member becomes high or strict in view of improvement in vehicle safety, and further fuel economy is taken into consideration for the global environment. Improvement—lightening—requirements are increasing. However, with the above-described conventional reinforcing structure, it has become increasingly difficult to satisfy both of the demands for lightening and the improvement of collision resistance performance, which are thus advanced.
[0013]
On the other hand, especially for relatively large profiles such as center pillars, in order to speed up the input of impact load to the collision-resistant member, a reinforcing member with a relatively small cross-sectional shape that minimizes the weight increase, A structure that is arranged outside the vehicle body via a separator has also been devised. However, the weight increase of the separator is very large, and there is a great limitation in improving the shock absorption of the hollow structural member.
[0014]
For this reason, there has been a demand for a car body structural material (car body part) exhibiting shock absorbing performance while efficiently exhibiting energy absorbing performance at the time of collision and minimizing an increase in the number of parts and weight as much as possible.
[0015]
Accordingly, an object of the present invention is to provide a vehicle body structural material and a collision-resistant reinforcing material having improved shock absorption against a vehicle collision by minimizing an increase in the weight and the number of parts of the hollow structural member. is there.
[0016]
[Means for Solving the Problems]
In order to achieve this object, the gist of the vehicle body structural material of the present invention is to provide a hollow aluminum structural member for reinforcement inside a hollow structural member formed by a molded panel in a width direction or a longitudinal direction of the hollow structural member. The aluminum alloy hollow profile has a curved shape in which a part of the hollow profile projects in the vehicle body collision direction determined with respect to the hollow structural member in the longitudinal direction. That is, the aluminum alloy hollow shape member is joined to the hollow structural member at both ends to form a shock absorbing portion for a vehicle body collision with the hollow structural member.
[0017]
In addition, the gist of the collision-resistant reinforcing material of the present invention is that the reinforcing aluminum alloy hollow shape used for the vehicle body structural material has a curved shape in which a part of the hollow shape extends in the longitudinal direction. It is.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a vehicle body structural material and a reinforcing aluminum alloy hollow profile of the present invention will be described in detail with reference to the drawings.
[0019]
FIG. 1 is a perspective view showing one embodiment of a reinforcing aluminum alloy hollow profile of the present invention, and FIG. 2 is a plan sectional view showing one embodiment of a vehicle body structural material in which the hollow profile is mounted inside a hollow structural member. FIG. 3 is a sectional view taken along the line AA of FIG. 2. FIG. 3 is a sectional view taken along the line AA of FIG.
[0020]
In FIG. 1, first, in a reinforcing aluminum alloy hollow profile 6a as a collision-resistant reinforcing material of the present invention, a central portion 11, which is a part of the hollow profile, protrudes outward (in the direction of vehicle collision, arrow F). For example, while having a curved shape in the shape of an arc in the longitudinal direction, the hollow structural member has, at both ends 12a and 12b, a joint with a hollow structural member such as an inner member.
[0021]
The cross section of this hollow profile 6a is a vertical straight front flange (front vertical wall portion) 7, and two straight lines which are substantially orthogonal to the front flange 7 and support the front flange 7 from the rear side in a substantially horizontal direction. And a straight rear flange (rear wall portion) 8 that is substantially perpendicular to the

webs

9 and 10. In addition, the front surface to the rear surface are represented by a positional relationship with respect to the vehicle body collision direction (arrow F). The front flange 7 and the rear flange 8 have overhanging

flanges

7a, 7b and 8a, 8b which extend in the vertical direction beyond the width of the

webs

9 and 10.
[0022]
Next, in FIGS. 2 and 3, in the vehicle body structural material of the present invention, the aluminum alloy hollow profile 6a of FIG. 1 has a curved shape in the horizontal positional relationship of FIG. It is arranged in the hollow space 13 of the hollow structural member 1a with the central portion 11 of the hollow profile protruding in the determined vehicle collision direction (arrow F, above the figure, outside the hollow structural member). Further, the overhang height (overhang amount) of the central portion 11 of the hollow profile is formed so as to extend from the outer panel 2 made of steel plate to a position where a predetermined clearance (determined by construction problems) is provided.
[0023]
Further, in the vertical positional relationship shown in FIG. 3, the hollow structural member 1a is arranged so that the front flange 7 and the rear flange 8 of the hollow profile 6a are substantially vertical (so that the

webs

9, 10 are substantially horizontal). It is arranged in the hollow space 13.
[0024]
As shown in FIG. 2, the aluminum alloy hollow shape member 6a is directly (or from the viewpoint of corrosion resistance, a bracket or the like) at both ends 12a and 12b of the hollow structural member 1a and the vertical wall 3a on the steel panel inner panel 3 side. ), And is rigidly connected or fixed to the vehicle body or the vehicle body structure by an appropriate general-purpose connecting means such as welding or mechanical connection such as a bolt. The rigid connection with the vehicle body or the vehicle body structure at both ends 12a and 12b of the hollow profile 6a is important from the viewpoint of ensuring a sufficient reaction force at the time of collision. In a normal body structure, these reinforcing hollow members (collision-resistant members) are combined with the inner panel (inner member) constituting the back surface of the hollow structural members because of their function and the structure of the hollow structural members. Preferably. However, as long as the function can be exhibited, it may be connected to an outer member of the hollow structural member according to the structure of the hollow structural member.
[0025]
On the other hand, in the present invention, it is not necessary to rigidly connect or fix the overhanging portion such as the central portion 11 of the hollow member to the outer panel.
[0026]
Hereinafter, the mechanism of the effect of improving the energy absorption of the aluminum alloy hollow profile 6a of the present invention will be described. Now, when a load (external force) due to a collision or the like is applied to the aluminum alloy hollow profile 6a via the head 2a of the outer panel 2 from the direction of arrow F, the aluminum alloy hollow profile 6a of the present invention is Since it has a curved shape that protrudes in the direction (arrow F) (has an arc-shaped central portion 11), the protruding central portion 11 does not delay with respect to a collision load without time delay. It is possible to quickly absorb the energy of the collision load.
[0027]
In addition, the curved shape of the projecting portion that projects outward such as the central portion 11 of the hollow member is not necessarily arc-shaped as long as the projecting portion can absorb the energy of the collision load without time delay. You don't have to. For example, a square, trapezoidal or other convex projecting portion shape, or a substantially arc-shaped projecting portion shape having a concave portion at the tip is provided, and the reinforcing hollow shape is curved. The shape is appropriately selected. However, as described later, in order to prevent bending buckling in the longitudinal direction of the hollow profile due to the impact load and to increase the amount of energy absorption, the overhanging portion should have a curved overhanging shape such as the above-mentioned arc shape. Is preferred. Similarly, the position at which the hollow profile is projected outward (the portion where the projection is provided) is appropriately selected depending on the energy absorption site of the structural member to be applied. That is, even if it is not necessarily at one central portion, a portion deviated to one of the longitudinal end portions of the hollow profile or a plurality of portions in the longitudinal direction of the hollow profile protrudes outward, and the curved shape is changed to the longitudinal shape of the hollow profile. A plurality of overhangs having the same shape or different shapes may exist over the direction.
[0028]
On the other hand, in the conventional structural part (FIG. 10) using the linear hollow member as the reinforcing member 5b, the energy absorbing means is provided only by the deformation of the outer panel 2 in the initial stage of the collision, and compared with the structure of the present invention. In particular, a difference occurs in the amount of energy absorption at the beginning of the collision. Further, in the structure in which the reinforcing plate 5a is directly joined to the outer panel (FIG. 9), the outer panel and the reinforcing plate 5a buckle in the middle stage of the collision, and the energy absorption is reduced.
[0029]
Further, in the structure of the present invention, since the aluminum alloy hollow profile 6a has a curved shape that extends in the longitudinal direction or a protruding shape in an arc shape (arch shape), bending buckling with respect to a collision load occurs as described above. There is also an advantage that it is difficult. If the aluminum alloy hollow profile is linear as in the prior art, the compressive load during bending deformation is shared only by the compression side flange 7, and when the initial load is applied, the center of the compression side flange 7 Local buckling of only the compression side flange 7 is likely to occur at the part. If such local buckling occurs in the compression-side flange 7, the compression-side flange 7 has a reduced ability to bear the subsequent compressive stress, and the energy absorption is greatly reduced. .
[0030]
Further, in the case of the conventional linear aluminum alloy hollow profile, when the compression side flange 7 buckles locally, in addition to this, the compression side flange 7 and the web 9, Ten crushing deformations (local buckling at the center) occur. When this crushing deformation occurs, the tensile stress of the tension side flange 8 does not increase thereafter, and the bending load resistance further decreases, so that the energy absorption amount is further reduced.
[0031]
Therefore, the central portion 11 of the aluminum alloy hollow profile 6a of the present invention protrudes in an arc shape in the vehicle body collision direction, so that the compression-side flange 7 does not locally buckle, meaning the improvement in energy absorption. Is big. This effect is exerted not only when a load is applied to the central portion of the central portion 11 of the hollow profile 6a, but also when it is applied to an arc-shaped projection other than the central portion of the central portion 11. This is similarly exerted in the overhang portion having a shape other than the arc shape described above. Therefore, it is an advantage of the present invention that the deviation of the point of application of the collision load from the center of the overhanging portion which can actually occur can be largely covered.
[0032]
In addition, although this structure has a sufficient effect by simply joining the reinforcing material to the inner panel, the joint of the reinforcing material matches the joint with the cross member, and the load is released to the cross member side. With such a structure, it is possible to further increase the amount of energy absorption.
[0033]
The overhang amount (overhang height) of the overhang portion such as the central portion 11 of the aluminum alloy hollow shape member 6a is determined by the assumed vehicle body collision load amount, Since the required or required energy absorption amount is different, it is appropriately designed depending on this and the size of the hollow space 13 of the hollow structural member 1a (length or width of the hollow structural member 1a). If the size of the hollow space 13 of the hollow structural member 1a is large, it is possible to increase the amount of overhang of the overhang such as the central portion 11 of the hollow profile 6a.
[0034]
Body structural materials such as pillars, doors, side sills, and the like corresponding to side collisions in which a vehicle body collision occurs from both sides of the vehicle body require a large amount of the hollow space and a large amount of energy absorption for occupant protection. Application of the present invention is desired. In the door and the side sill, the aluminum alloy hollow profile 6a is extended in a substantially horizontal direction at a position corresponding to a collision (side collision) in these hollow spaces, and the projecting direction of the central portion 11 is also extended in a substantially horizontal direction. put out. On the other hand, in a pillar or the like which is a vertical member, the aluminum alloy hollow profile 6a is extended substantially vertically at a position corresponding to a collision (side collision) in these hollow spaces, and The projecting direction is extended substantially horizontally.
[0035]
In the center pillar, it is most effective to provide an overhang near the height of the vehicle body bumper, which is often subjected to a load during a side collision. In the center pillar or door structure, the overhang is provided at the center where deformation is most likely to occur Is effective.
[0036]
In addition, the length of the protruding portion such as the arc shape or the curved shape in the longitudinal direction and the magnitude of the curvature in the hollow profile 6a are the same as the above-mentioned design standard of the protruding amount of the central portion 11 of the hollow profile 6a. . Also, the length and area of the

joints

12a and 12b, or the joining means are appropriately designed.
[0037]
In the present invention, as can be seen particularly from FIG. 3, the conventional steel plate reinforcing separator (separator 24a in FIGS. 9, 9 and 10) that separates the outer panel 2a and the inner panel 3a made of steel plate is unnecessary. In other words, the energy absorption amount can be increased without providing a conventional steel plate-made reinforcing separator. Therefore, there is an effect that the structural member can be reduced in weight and the weight increase due to the reinforcing profile can be minimized.
[0038]
Hereinafter, the cross-sectional shape of the reinforced aluminum alloy hollow profile will be described. In the hollow profile 6a shown in FIG. 1, the front flange 7 is supported from the rear side in a substantially horizontal direction by

webs

9 and 10, which are substantially perpendicular to the front flange 7, so that the front flange 7 is moved in the direction of F by a vehicle collision. Even when an impact is applied from the above, the rigidity of the structure increases, and buckling becomes difficult. As a result, even if the collision load is relatively large, bending and buckling of the front flange 7 and the like can be prevented, and the energy absorption amount of the collision load can be increased. The cross-sectional shape of the hollow member is appropriately selected in consideration of minimizing weight increase.
[0039]
In addition, the front flange 7 and the rear flange 8 of the hollow profile 6a shown in FIG. 1 have the overhanging

flanges

7a, 7b and 8a, 8b, respectively, so that the front flange 7 and the rear flange 8 are sufficiently separated. It is possible to respond to a vehicle collision with the wall area and the collision load direction. That is, even when an impact is applied to the front flange 7 from the direction of F due to the collision of the vehicle body, the bending rigidity of the front flange 7 is increased, so that the front flange 7 can be prevented from being crushed or damaged, and the entire hollow profile 6a including the front flange 7 can be prevented. Is deformed in the collision direction (lateral direction in the figure), which is preferable in absorbing the impact load.
[0040]
In addition, as will be described later, the inner panel side of the hollow structural member can be welded or mechanically joined by bolts or the like at the protruding

flanges

8a and 8b of the rear flange 8, and from the viewpoint of jointability and joining workability. Is also preferred.
[0041]
The front flange 7 and the rear flange 8 or the

webs

9 and 10 need not be linear, but may be curved such as an arc bulging outward or inward. Also, the surface may not be flat, but may have irregularities.
[0042]
In addition, in the case of the present invention, in order to achieve the advantage and the purpose of adopting the aluminum alloy material for weight reduction, it is preferable to use a relatively thin reinforcing aluminum alloy hollow material having a thickness of 5 mm or less. If the thickness exceeds 5 mm, the difference between weight and strength is not so different from that of steel, and the advantage of adopting an aluminum alloy material for weight reduction is impaired. In other words, the reinforcing aluminum alloy hollow profile of the present invention has an advantage that the impact absorbing effect at the time of a vehicle collision can be enhanced even when the thickness is as thin as 5 mm or less. For this purpose, it is preferable that the aluminum alloy material used has a high strength of not less than 200 MPa and a 0.2% proof stress.
[0043]
Aluminum alloy materials satisfying these required characteristics include general-purpose (standard) types such as 3000 series, 5000 series, 6000 series, and 7000 series defined in AA to JIS standards, which are generally used for structural members of this kind. An aluminum alloy material (a rolled sheet material or an extruded shape material that has been tempered to meet the required performance such as O 2, T4, T6, and T7) is preferably and selectively used. Among them, aluminum alloy materials such as 6000 series and 7000 series which have good moldability and relatively high yield strength are preferable.
[0044]
The aluminum alloy hollow profile according to the present invention itself satisfies these conditions, and manufactures a linear hollow profile manufactured by an ordinary method, such as extrusion, forming a rolled plate, and welding. it can. Then, by bending or the like, it is possible to form an appropriate curved shape in the longitudinal direction of the hollow profile, for example, to make a part such as a central portion of the hollow profile into an arc shape.
[0045]
【Example】
Hereinafter, examples of the present invention will be described.
The vehicle body structural material (simulating the center pillar) of the invention example shown in FIGS. 2 and 3 was modeled as shown in a sectional view in FIG. 6B. The basic model of this is a molded panel made of a steel plate composed of an outer 2 and an inner 3 (FIG. 6A). Then, the cross-sectional area (mm ² ), The cross-sectional area (mm) of the reinforcing material 6a (aluminum alloy hollow profile) ² ) And the wall thickness (mm) were changed, the load-displacement relationship of the vehicle body structural material, the vehicle structural material weight, the energy absorption (E / A amount, when the displacement was 150 mm), and the maximum load were obtained.
[0046]
For comparison, the conventional vehicle body structural materials of FIGS. 9 and 10 are modeled as shown in the cross-sectional views of FIGS. 6C and 6D, respectively. E / A amount, displacement amount 150 mm) and maximum load were determined. The results are shown in Table 1 and FIG.
[0047]
Here, the models of FIGS. 6C and 6D of the comparative example are similar to those shown in FIGS. 9 and 10 except that the hollow body structural members including the outer 2 and the inner 3 shown in FIG. A reinforcing plate 5a made of an alloy is provided with a reinforcing material 5b. FIG. 6 (b) of the invention is shown in FIG. 6 (a) in which a reinforcing member 6a having a central portion projecting and curved into the hollow structural member as shown in FIG. It is provided. In the reference example shown in Table 1, as shown in FIG. 6 (c), a reinforcing panel 5a of a 980N class high-strength steel plate is directly joined to the back surface of the outer 2.
[0048]
The 0.2% proof stress of the reinforcing aluminum alloy hollow profile was 300 MPa. The bending load is statically pressed against a part (a position 400 mm from the left end and 800 mm from the right end) of a body structural material (outer 2) having a length of 1200 mm using a cylindrical tool having a diameter of 200 mm as shown in FIG. Performed under conditions. This analysis was performed using a three-point bending analysis model and general-purpose dynamic explicit solution software LS-DYNA3D.
[0049]
Table 1 shows that, as a precondition for analysis, a steel sheet formed panel (total of outer 2 and inner 3) cross-sectional area (mm ² ), Cross section of aluminum alloy hollow profile (mm ² ), Wall thickness (mm), and total weight of vehicle body structural material (kg / m). The energy absorption amount (kN-m, at a displacement of 300 mm) obtained from the analysis result, and the ratio (a / b) between the total weight (b) of the vehicle body structural material and the energy absorption amount (a) are shown. FIG. 7 shows the load-displacement relationship of the vehicle body structural material.
[0050]
As is clear from Table 1, the body structural materials of Invention Examples 2 and 3 of the type shown in FIG. 2 have a ratio (a / b) between the energy absorption amount and the weight of the vehicle body structural material as compared with Comparative Examples 4 and 5. It can be seen that the energy absorption amount can be increased as compared with the case of using a linear extruded section with the same cross-sectional shape in the related art. Further, it can be seen that the E / A amount is large and the weight can be significantly reduced as compared with the reference example in which the reinforcing panel of a high-strength 980N class high-tensile steel plate is directly joined to the outer.
[0051]
In the load-displacement relationship shown in FIG. 7, the vehicle body structural material of Inventive Example 2 of the type shown in FIG. 2 has no load-displacement curve having a peak at the start of the initial collision, and is more gradual than Comparative Examples 4 and 5. Shows an ideal load-displacement curve which increases, and the amount of energy absorption is large. This means that even in the early stage when a large bending load is applied, the hollow profile of the invention does not cause local buckling of the compression side flange, and continuous and large energy absorption due to bending deformation of the entire profile. Is performed.
[0052]
On the other hand, in FIG. 7, in Comparative Example 5, the peak of the load-displacement curve at the rise was high, and the load decreased in the late stage of the collision. This indicates that both the outer and the reinforcing material buckled, resulting in a load reduction due to crushing deformation of the cross section. Further, in Comparative Example 4, since the reinforcing material did not come into contact with the member to be impacted in the early stage of the collision, the rise of the load in the early stage of the collision was delayed, and the energy absorption amount decreased accordingly. It is clear that the delay in the rise of the load becomes more remarkable as the hollow region of the target hollow structural member becomes larger. In other words, it can be said that the effect of the present invention increases as the collision-resistant member has a larger hollow region.
[0053]
[Table 1]

[0054]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the weight increase of a hollow structural member can be minimized, and the vehicle body structural material and the aluminum alloy hollow shape for reinforcement which improved the impact absorption with respect to the vehicle body collision can be provided. Since the present invention has such excellent effects, it is suitable to be applied to a vehicle body structural material such as a pillar, a door, a side sill or the like corresponding to a side collision in which a vehicle body collision occurs from both sides of the vehicle body.
For this reason, while greatly contributing to the weight reduction of the automobile, the use of the Al alloy material for the vehicle body structural material is greatly expanded, and the industrial value is high.
Further, there is an effect that the shock absorbing property and the collision safety of the automobile body are sufficiently functioned or secured, which has great social significance.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a reinforcing aluminum alloy hollow profile of the present invention.
FIG. 2 is a plan sectional view showing one embodiment of the vehicle body structural material of the present invention.
FIG. 3 is a sectional view taken along line AA of FIG. 2;
FIG. 4 is a sectional view showing another embodiment of the vehicle body structural material of the present invention.
FIG. 5 is a sectional view showing another embodiment of the vehicle body structural material of the present invention.
6 (a) shows a basic model, FIG. 6 (b) shows a comparative example, FIG. 6 (c) shows an example of the invention, and FIG. It is sectional drawing which shows an example each.
FIG. 7 is an explanatory diagram showing a load-displacement curve of the vehicle body structural material of the present invention.
FIG. 8 is an explanatory diagram showing test conditions for analyzing the impact absorbing performance of the vehicle body structural material of the present invention.
FIG. 9 is a front sectional view of a conventional vehicle body structural material.
10A and 10B show a conventional vehicle body structural material, in which FIG. 10A is a front sectional view and FIG. 10B is a plan sectional view.
11A and 11B show a conventional vehicle body structural material, in which FIG. 11A is a front sectional view, and FIG. 11B is a plan sectional view.
12A and 12B show a conventional vehicle body structural material, in which FIG. 12A is a front sectional view, and FIG. 12B is a plan sectional view.
13A and 13B show a conventional vehicle body structural material, in which FIG. 13A is a front sectional view, and FIG. 13B is a plan sectional view.
[Explanation of symbols]
1: vehicle body structural material, 2: outer panel, 3: inner panel, 4: separator
5: reinforcing material, 6: reinforced aluminum alloy hollow profile, 7, 8: flange,
9, 10: Web, 11: Arc-shaped curved (extended) part, 12, end part

Claims

A body structural member having a hollow aluminum structural member for reinforcement extending inside a hollow structural member constituted by a molded panel, in a width direction or a longitudinal direction of the hollow structural member, wherein the aluminum alloy hollow shape is provided. While the material has a curved shape in the longitudinal direction in which a part of the hollow profile projects in the vehicle body collision direction determined with respect to the hollow structural member in the longitudinal direction, the hollow structural member is formed at both ends of the aluminum alloy hollow profile. A vehicle body structural material which is joined to form a shock absorbing portion for a vehicle body collision with a hollow structural member.

The vehicle body structural member according to claim 1, wherein the vehicle body structural member is a component located on a vehicle body side surface selected from a pillar, a door, and a side sill, and the vehicle body collision is a side collision.

The body structural material according to claim 1 or 2, wherein the proof stress of the aluminum alloy hollow profile is 200 MPa or more.

The vehicle body structural material according to any one of claims 1 to 3, wherein the aluminum alloy hollow profile is manufactured by hot extrusion.

The vehicle body structural material according to any one of claims 1 to 4, wherein a reinforcing middle rib is provided in the aluminum alloy hollow profile.

A hollow aluminum alloy material for reinforcement used in the vehicle body structural material according to any one of claims 1 to 5, which has a curved shape in which a part of the hollow aluminum alloy material projects in a longitudinal direction. A collision-resistant reinforcing material characterized in that: