JP3778961B2

JP3778961B2 - Manufacturing method of tubular member for vehicle body structure

Info

Publication number: JP3778961B2
Application number: JP24445194A
Authority: JP
Inventors: 久男谷川; 公雄伊藤; 隆博鈴木; 成幸中川; 謙二金森
Original assignee: Mitsubishi Aluminum Co Ltd; Nissan Motor Co Ltd
Current assignee: Mitsubishi Aluminum Co Ltd; Nissan Motor Co Ltd
Priority date: 1994-10-07
Filing date: 1994-10-07
Publication date: 2006-05-24
Anticipated expiration: 2021-05-24
Also published as: JPH08108237A

Description

【０００１】
【産業上の利用分野】
本発明は自動車の車体を構成する筒状の構造部材に係り、さらに詳しくは、２次元または３次元方向に湾曲され、略多角形状の断面を有する車体構造用筒状部材の製造方法に関するものである。
【０００２】
【従来の技術】
従来、自動車の車体は、鋼板にプレス成形加工を施したり、押し出し成形した鋼管を折曲げ加工して得られた様々な形状の車体部材を組み合わせ、スポット溶接等を用いて各車体部材を接合し一体化することにより製造されているが、近年、車体のより軽量化を図るために、鋼板の替わりにアルミニウム合金やチタン合金等の軽合金を使用することが検討されている。
例えば、車体前方のエンジンルーム下部から後方に向かって延び客室前方フロアの構造部材に接続されるフロントサイドフレームメンバー、客室後方フロアの構造部材から後方に延びトランクルーム下部に達するリヤサイドフレームメンバー等の構造部材は、その長手方向の全長にわたってほぼ一定の断面形状の筒状部材とする必要がある。
【０００３】
図９は、従来の車体構造用筒状部材の取り付け部位を示す自動車の斜視図であり、図において、１は車体であり、２は車体１の前方を構成する一対のフロントサイドフレームメンバー、３は車体１の後方右側を構成する一対のリヤサイドフレームメンバーである。
車体前方右側のフロントサイドフレームメンバー２Ｒは、その前端部分２ａおよび後端部分２ｃが直線状とされ、これらの直線状部分２ａ，２ｃを結ぶ部分２ｂは、前輪４との当たりを避けるため、後方に延びる途中で下方かつ外側に向かって３次元に曲げられている。そして、このフロントサイドフレームメンバー２Ｒには、フロントホイールエプロン等のパネル部材と接続するために、垂直上方に延びるフランジ２ｄが一体に設けられている。
【０００４】
同様に、車体後方右側のリヤサイドフレームメンバー３Ｒは、その前端部分３ａおよび後端部分３ｃは直線状とされ、これらの直線状部分３ａ，３ｃを結ぶ部分３ｂは、後輪５との当たりを避けるため、後方に延びる途中で上方かつ車体内側に向かって３次元に曲げられている。そして、このリヤサイドフレームメンバー３Ｒには、トランクフロア等と接続するために、水平方向外方に延びる一対のフランジ３ｄ，３ｅが一体に設けられているとともに、このフランジ３ｄの後輪５に近接する部分３ｆは、リヤホイールエプロンと接続するために、垂直上方に延びるように折曲げられている。
【０００５】
これらフロントサイドフレームメンバー２やリヤサイドフレームメンバー３等の構造部材は、フランジを有する矩形断面に押し出し成形されたアルミニウム合金製の角管をプレス加工等により曲げ加工することにより、効率よく成形することができることから、以前より車体軽量化の対象部品として注目されている。
【０００６】
【発明が解決しようとする課題】
上述した様に、自動車に用いられる構造部材は、フランジを有するものが用いられることが多く、また、その断面形状は多角形であることが多い。
しかしながら、例えば、アルミニウム合金製の角管は、鋼製の角管と異なり機械的強度や剛性が低く、単に曲げ加工を施しただけでは角管の壁面に曲げ加工に起因するシワが発生し易いという問題点があった。また、該角管に曲げ加工を施した場合、フランジに展性が無いために大きく変形してしまい、所望の形状が得られないという問題点もあった。これらの問題点は、機械的強度、及び車体のパネル部材と溶接するための形状精度が強く求められる車体構造部材の品質を低下させる主要因になっている。
【０００７】
本発明は上記の事情に鑑みてなされたものであって、上述したフロントサイドフレームメンバーやリヤサイドフレームメンバー等のように、２次元や３次元方向に湾曲された略多角形状の断面を有する車体構造用筒状部材を、曲げ加工にともなう壁面のシワ、フランジの変形等の不具合が生じること無く製造することができる車体構造用筒状部材の製造方法を提供することを目的とする。
【０００８】
【課題を解決するための手段】
上記課題を解決するために、本発明は次の様な車体構造用筒状部材の製造方法を採用した。
すなわち、請求項１記載の車体構造用筒状部材の製造方法は、外側の長手方向に沿ってフランジが一体に形成されかつ１つ以上の中空部を有する略多角形状の断面の筒状部材を押し出し成形し、この押し出し成形された筒状部材を、その断面形状に係合しかつ長手方向に湾曲した金型内に投入し、前記フランジを挟持しかつ該金型を型締めしつつ前記筒状部材の中空部内に適宜に予備圧力を負荷し、さらに圧力を増加させて前記筒状部材を湾曲させるとともに、その壁面を膨出させて前記金型に密着させることを特徴とするものである。
【０００９】
請求項２記載の車体構造用筒状部材の製造方法は、外側の長手方向に沿ってフランジが一体に形成されかつ１つ以上の中空部を有する略多角形状の断面の筒状部材を押し出し成形し、この押し出し成形された筒状部材に曲げ加工を施し、この曲げ加工が施された筒状部材をその曲げ形状及び断面形状に係合した金型内に投入し、前記フランジを挟持しつつ保持し、この筒状部材の内部に適宜に圧力を負荷し、その壁面を膨出させて前記金型に密着させることを特徴とするものである。
【００１０】
請求項３記載の車体構造用筒状部材の製造方法は、外側の長手方向に沿ってフランジが一体に形成されかつ１つ以上の中空部を有する略多角形状の断面の筒状部材を押し出し成形し、この押し出し成形された筒状部材に曲げ加工を施し、この曲げ加工が施された筒状部材をその曲げ方向と異なる長手方向に湾曲しかつ断面形状に係合した金型内に投入し、前記フランジを挟持しかつ前記金型を型締めしつつ前記筒状部材の中空部内に適宜に予備圧力を負荷し、さらに圧力を増加させて前記筒状部材を湾曲させるとともに、その壁面を膨出させて前記金型に密着させることを特徴とするものである。
【００１６】
【作用】
本発明の請求項１記載の車体構造用筒状部材の製造方法では、押し出し成形された外側の長手方向に沿ってフランジが一体に形成されかつ１つ以上の中空部を有する略多角形状の断面の筒状部材を、その断面形状に係合しかつ長手方向に湾曲した金型内に投入し、前記フランジを挟持しかつ該金型を型締めしつつ前記筒状部材の中空部内に適宜に予備圧力を負荷し、さらに圧力を増加させて前記筒状部材を湾曲させるとともに、その壁面を膨出させて前記金型に密着させる張り出し加工を施すことにより、曲げ加工時に発生した壁面のシワが伸ばされ、消失する。また、張り出し加工を施す際に、壁面が膨出して前記金型に密着し、精度の高い複雑な略多角形状の断面を有する２次元曲げ形状のフランジ付筒状部材が得られる。
【００１７】
請求項２記載の車体構造用筒状部材の製造方法では、押し出し成形された外側の長手方向に沿ってフランジが一体に形成されかつ１つ以上の中空部を有する略多角形状の断面の筒状部材に曲げ加工を施し、この曲げ加工が施された筒状部材をその曲げ形状及び断面形状に係合した金型内に投入し、前記フランジを挟持しつつ保持し、この筒状部材の内部に適宜に圧力を負荷し、その壁面を膨出させて前記金型に密着させることにより、曲げ加工時に発生した壁面のシワが伸ばされ、消失する。また、壁面が膨出した際にフランジが位置ずれを起こすことなく前記金型に密着し、精度の高い複雑な略多角形状の断面を有する２次元曲げ形状のフランジ付筒状部材が得られる。
【００１８】
請求項３記載の車体構造用筒状部材の製造方法では、曲げ加工が施された外側の長手方向に沿ってフランジが一体に形成されかつ１つ以上の中空部を有する略多角形状の断面の筒状部材をその曲げ方向と異なる長手方向に湾曲しかつ断面形状に係合した金型内に投入し、前記フランジを挟持しかつ前記金型を型締めしつつ前記筒状部材の中空部内に適宜に予備圧力を負荷し、さらに圧力を増加させて前記筒状部材を湾曲させるとともに、その壁面を膨出させて前記金型に密着させることにより、張り出し加工時に膨出した壁面及びフランジと金型との間に位置ずれ等が生じるおそれがなくなり、加工時に壁面にシワ等が生じることのない、精度の高い複雑な略多角形状の断面を有する３次元曲げ形状のフランジ付筒状部材が得られる。
【００２４】
【実施例】
以下、本発明の車体構造用筒状部材の製造方法の各実施例について、図面に基づいて説明する。
（第１実施例）
図１は本発明の一実施例のフロントサイドフレームメンバー（車体構造用筒状部材）の製造方法を示す過程図である。
まず、図１（ａ）に示す様に、第１工程は、アルミ材からなる筒状部材１１を押し出し成形する押し出し成形工程であり、この筒状部材１１は、長手方向に矩形状の中空部１２が形成された肉厚一定の筒状部分１１ａと、該筒状部分１１ａの外側の角部に長手方向に沿って一体に立設され、外側に向かって直線状に延びる肉厚一定のフランジ１１ｂとを有するように押し出し成形される。
【００２５】
次に、図１（ｂ）に示す様に、第２工程は、前記第１工程で押し出し成形された直線状の筒状部材１１を鉛直面内で湾曲させる曲げ加工工程である。
この曲げ加工は、図２及び図３に示す様な加工装置を用いて加工される。
この加工装置２１は、前記筒状部材１１の断面形状に係合しかつ垂直平面内で該筒状部材１１の長手方向に沿って湾曲したダイスを構成する金型２２〜２４と、金型２２〜２４の長手方向の両端部に着脱自在に設けられ、曲げ加工を施すべき筒状部材１１の両端部を固定する口金２５，２５と、各口金２５に設けられ該筒状部材１１内に圧力を負荷するエアホース２６とにより構成されている。
【００２６】
ここでは、予め金型２２〜２４を互いに離間する方向、すなわち図３の面方向に移動し、金型２２〜２４を開いた状態にしておく。
まず、筒状部材１１の両端部を口金２５，２５により固定し、この筒状部材１１を金型２２〜２４内に投入し、金型２２〜２４を互いに近接する方向に移動し、図４に示すように、各金型２２〜２４を型締めしつつ筒状部材１１の中空部１２内にエアホース２６により適宜に予備圧力を負荷し、さらに圧力を増加させて筒状部材１１を湾曲させる。
【００２７】
以上により、直線状に延びる筒状部材１１は、図１（ｂ）に示す様に、フランジ１１ｂを有し断面形状が高精度の矩形となる略Ｓ字型の筒状部材１３に加工される。そして、該筒状部材１３の両端部を切断して所定の長さとすれば、フロントサイドフレームメンバーとすることができる。また、リヤサイドフレームメンバーも、全く同一の製造方法で製造することができる。
【００２８】
以上説明した様に、上記実施例のフロントサイドフレームメンバーの製造方法によれば、長手方向に矩形状の中空部１２が形成された筒状部分１１ａと、筒状部分１１ａの外側の角部に長手方向に沿って一体に立設されたフランジ１１ｂとを有する筒状部材１１を押し出し成形し、押し出し成形された筒状部材１１を、その断面形状に係合しかつ長手方向に湾曲した金型２２〜２４内に投入し、金型２２〜２４を型締めしつつ筒状部材１１の中空部１２内に適宜に予備圧力を負荷し、さらに圧力を増加させて筒状部材１１を湾曲させることとしたので、曲げ加工時に発生した壁面のシワを伸ばし消失させることができ、また、壁面が膨出して前記金型２２〜２４に密着し、精度の高い矩形状の断面を有する筒状部材１３を得ることができる。したがって、曲げ加工にともなう壁面のシワ等の不具合のない筒状部材１３を製造することができる。
【００２９】
また、筒状部材１１は、その外側表面にフランジ１１ｂが一体に押し出し成形されているので、曲げ加工を行う際に、フランジ１１ｂを任意の方向に延びるように曲げ加工し、かつ曲がり変形を矯正することができ、精度の高いフランジ１１ｂを有する筒状部材１３を得ることができる。
【００３０】
なお、本実施例では、矩形状の断面を有する筒状部材１１の製造方法について説明したが、上記実施例に限定されることなく様々な断面形状のもの、例えば、６角形等の筒状部材の製造が可能である。また、筒状部材１１は、複数の中空部を有するように、筒内に長手方向に延在する１つ以上のリブを形成した構成であってもよい。複数のリブが形成されている場合、これらのリブは互いに平行であっても、互いに交差していてもよい。
【００３１】
（第２実施例）
図５は本発明の第２実施例のフロントサイドフレームメンバーの製造方法を示す図である。
まず、図５（ａ）に示す様に、第１工程は、アルミ材からなる筒状部材１１を押し出し成形する押し出し成形工程であり、第１実施例と同様に、この筒状部材１１は、長手方向に矩形状の中空部１２が形成された肉厚一定の筒状部分１１ａと、該筒状部分１１ａの外側の角部に長手方向に沿って一体に立設され、外側に向かって直線状に延びる肉厚一定のフランジ１１ｂとを有するように押し出し成形される。
【００３２】
次に、図５（ｂ）に示す様に、第２工程は、前記第１工程で押し出し成形された直線状の筒状部材１１を鉛直面内で所定形状に湾曲させる曲げ加工工程である。
この曲げ加工方法は、筒状部材１１に引張り力を加えながら鉛直面内に湾曲させ筒状部材３１とするもので、例えば、図６に示す様な曲げ加工装置を用いて加工される。
この曲げ加工装置４１は、前記筒状部材１１の外形に合う様に溝４２ａが設けられ中心Ｃを有する車輪状の回転曲げ型４２と、該回転曲げ型４２に固定された締め付け型の下型４３及び上型４４と、下型４３及び上型４４と同一軸線上に設けられ、筒状部材１１のフランジ１１ｂを把持し曲げ加工の途中で図中左側から右側に移動する移動押さえ型４５とから概略構成されている。
【００３３】
ここでは、前記筒状部材１１の一方の端部を下型４３と上型４４により挟持し、回転曲げ型４２に固定し、かつ、該筒状部材１１を水平方向に延在するように配置し、そのフランジ１１ｂを移動押さえ型４５により把持する。そして、筒状部材１１の断面形状が変形しないように中空部１２に図示しない中子を挿通する。
そして、この状態で前記回転曲げ型４２をその中心Ｃの廻りにゆっくりと図中右回転させ、該筒状部材１１を前記回転曲げ型４２の溝４２ａの中心の曲率半径に合わせて鉛直面内に上向きに凸に曲げ加工する。また、筒状部材１１の鉛直面内に下向きに凸とされる曲げ部分も、上述と同様の装置を用いて曲げ加工する。
【００３４】
この時、筒状部分１１ａ及びフランジ１１ｂの曲げ加工部分には、それぞれシワ３１ａ，３１ｂが発生し、座屈の発生の一因となる。そこで、シワ３１ａ，３１ｂを消失させる矯正加工を施す。
【００３５】
次に、図５（ｃ）に示す様に、第３工程は、前記第２工程で曲げ加工された筒状部材３１のシワ３１ａ，３１ｂを消失させる矯正加工工程である。
この矯正加工は、上記第１実施例で用いた加工装置を用いて加工される。
ここでは、予め金型２２〜２４を互いに離間する方向、すなわち図３の面方向に移動し、金型２２〜２４を開いた状態にしておき、筒状部材３１の両端部を口金２５，２５により固定し、この筒状部材３１を金型２２〜２４内に投入し、図７（ａ）に示すように、金型２２，２３をｘ−ｙ方向に移動して金型２４に当接し、各金型２２〜２４を型締めしつつ筒状部材３１のシワ３１ａ，３１ｂを伸ばす。次に、図７（ｂ）に示すように、中空部１２内にエアホース２６により適宜に予備圧力を負荷し、さらに圧力を増加させて筒状部材３１のシワ３１ａ，３１ｂを消失させ矯正する。
この際、フランジ１１ｂの曲がり変形も同時に矯正することができ、精度の高いフランジ３２ｂを得ることができる。
【００３６】
以上により、シワ３１ａ，３１ｂが消失した筒状部分３２ａ及びフランジ３２ｂを有する略Ｓ字型の筒状部材３２が製造される。
そして、該筒状部材３２の両端部を切断して所定の長さとすれば、フロントサイドフレームメンバーとすることができる。また、リヤサイドフレームメンバーも、全く同一の製造方法で製造することができる。
【００３７】
以上説明した様に、上記実施例のフロントサイドフレームメンバーの製造方法によれば、押し出し成形された筒状部材１１に曲げ加工を施し、さらに曲げ加工された筒状部材３１のシワ３１ａ，３１ｂを消失させる矯正加工を施すこととしたので、曲げ加工時に発生したシワ３１ａ，３１ｂを伸ばし消失させることができ、また、壁面が膨出して前記金型２２〜２４に密着し、精度の高い矩形状の断面を有する筒状部材３２を得ることができる。したがって、シワ３１ａ，３１ｂ等の不具合のない筒状部材３２を製造することができる。
【００３８】
なお、本実施例においても、上記実施例に限定されることなく様々な断面形状のもの、例えば、６角形等の筒状部材の製造が可能である。また、筒状部材１１は、複数の中空部を有するように、筒内に長手方向に延在する１つ以上のリブを形成した構成であってもよい。複数のリブが形成されている場合、これらのリブは互いに平行であっても、互いに交差していてもよい。
更に、曲げ加工に用いられる装置は、上記曲げ加工装置に限定されることなく、各種の曲げ加工装置より筒状部材１１の形状及び大きさ等に適合した曲げ加工装置を適宜選択すればよい。
【００３９】
（第３実施例）
図８は本発明の第３実施例のフロントサイドフレームメンバーの製造方法に用いられ、２次元に曲げ加工が施された筒状部材３１を３次元方向に湾曲させる加工装置を示す図である。
この加工装置５１は、前記筒状部材１１の断面形状に係合しかつ筒状部材１１を３次元方向に湾曲したダイスを構成する金型５２，５３と、金型５２，５３の長手方向の両端部に着脱自在に設けられ、曲げ加工を施すべき筒状部材１１の両端部を固定する口金２５，２５と、各口金２５に設けられ該筒状部材１１内に圧力を負荷するエアホース２６とにより構成されている。
【００４０】
次に、この加工装置５１を用いて、曲げ加工装置４１により２次元に曲げ加工が施された筒状部材３１を３次元方向に湾曲させ、その後シワ３１ａ，３１ｂを消失させる加工工程について説明する。
ここでは、予め金型５２，５３を互いに離間する方向に移動し、金型５２，５３を開いた状態にしておく。
まず、筒状部材３１の両端部を口金２５，２５により固定し、この筒状部材３１を金型５２，５３内に投入し、金型５２，５３を互いに近接する方向に移動し、各金型５２，５３を型締めしつつ中空部１２内にエアホース２６により適宜に予備圧力を負荷し、筒状部材３１を３次元方向に湾曲させる。
さらに圧力を増加させて筒状部材３１のシワ３１ａ，３１ｂを消失させ矯正する。
この際、フランジ１１ｂの曲がり変形も同時に矯正することができ、精度の高いフランジを得ることができる。
【００４１】
以上により、シワ３１ａ，３１ｂが消失した筒状部分３２ａ及びフランジ３２ｂを有する３次元方向に略Ｓ字型に湾曲した筒状部材が製造される。
そして、該筒状部材の両端部を切断して所定の長さとすれば、フロントサイドフレームメンバーとすることができる。また、リヤサイドフレームメンバーも、全く同一の製造方法で製造することができる。
【００４２】
以上説明した様に、上記実施例のフロントサイドフレームメンバーの製造方法によれば、曲げ加工された筒状部材３１を３次元方向に湾曲させ、その後シワ３１ａ，３１ｂを消失させる加工工程を施すこととしたので、３次元方向に湾曲させると共に曲げ加工時に発生したシワ３１ａ，３１ｂを伸ばし消失させることができ、精度の高い筒状部材を得ることができる。したがって、シワ３１ａ，３１ｂ等の不具合のない筒状部材を製造することができる。
【００４３】
なお、本実施例においても、上記各実施例に限定されることなく様々な断面形状のもの、例えば、６角形等の筒状部材の製造が可能である。また、筒状部材３１は、複数の中空部を有するように、筒内に長手方向に延在する１つ以上のリブを形成した構成であってもよい。複数のリブが形成されている場合、これらのリブは互いに平行であっても、互いに交差していてもよい。
【００４４】
【発明の効果】
本発明の請求項１記載の車体構造用筒状部材の製造方法によれば、押し出し成形された筒状部材を、その断面形状に係合しかつ長手方向に湾曲した金型内に投入し、前記フランジを挟持しかつ該金型を型締めしつつ前記筒状部材の中空部内に適宜に予備圧力を負荷し、さらに圧力を増加させて前記筒状部材を湾曲させるとともに、その壁面を膨出させて前記金型に密着させる張り出し加工を施すこととしたので、曲げ加工時に発生した壁面のシワを伸ばし消失させることができ、また、張り出し加工を施す際に、壁面が膨出して前記金型に密着し、精度の高い複雑な略多角形状の断面を有する筒状部材を得ることができる。したがって、曲げ加工にともなう壁面のシワ等の不具合のない２次元曲げ形状のフランジ付筒状部材を製造することができる。
【００４５】
請求項２記載の車体構造用筒状部材の製造方法によれば、曲げ加工が施された筒状部材をその曲げ形状及び断面形状に係合した金型内に投入し、前記フランジを挟持しつつ保持し、この筒状部材の内部に適宜に圧力を負荷し、その壁面を膨出させて前記金型に密着させることとしたので、曲げ加工時に発生した壁面のシワを伸ばし消失させることができ、また、壁面が膨出した際にフランジが位置ずれを起こすことなく該壁面を前記金型に密着し、精度の高い複雑な略多角形状の断面を有する筒状部材を得ることができる。したがって、曲げ加工にともなう壁面のシワ等の不具合のない２次元曲げ形状のフランジ付筒状部材を製造することができる。
【００４６】
請求項３記載の車体構造用筒状部材の製造方法によれば、曲げ加工が施された筒状部材をその曲げ方向と異なる長手方向に湾曲しかつ断面形状に係合した金型内に投入し、前記フランジを挟持しかつ前記金型を型締めしつつ前記筒状部材の中空部内に適宜に予備圧力を負荷し、さらに圧力を増加させて前記筒状部材を湾曲させるとともに、その壁面を膨出させて前記金型に密着させることとしたので、張り出し加工時に膨出した壁面及びフランジと金型との間に位置ずれ等が生じるおそれがなくなり、加工時に壁面にシワ等が生じることのない、精度の高い複雑な略多角形状の断面を有する３次元曲げ形状のフランジ付筒状部材を得ることができる。
【００５２】
以上により、例えば自動車車体のフロントサイドフレームメンバーやリヤサイドフレームメンバーのような、２次元または３次元に湾曲した略多角形状の断面を有する筒状の構造部材であっても、その壁面にシワ等の欠陥を生じること無く製造することができ、車体の重量軽減に大きく寄与することができる。
【図面の簡単な説明】
【図１】本発明の一実施例のフロントサイドフレームメンバー（車体構造用筒状部材）の製造方法を示す過程図である。
【図２】本発明の第１実施例のフロントサイドフレームメンバーの製造方法において用いられる加工装置の側面図である。
【図３】図２のＡ−Ａ線に沿う断面図である。
【図４】本発明の第１実施例のフロントサイドフレームメンバーの膨出加工の様を示す断面図である。
【図５】本発明の第２実施例のフロントサイドフレームメンバーの製造方法を示す過程図である。
【図６】本発明の第２実施例の曲げ加工用筒状部材を曲げ加工する際に用いられる曲げ加工装置の正面図である。
【図７】本発明の第２実施例のフロントサイドフレームメンバーの膨出加工の様を示す断面図である。
【図８】本発明の第３実施例のフロントサイドフレームメンバーの製造方法において用いられる加工装置の側面図である。
【図９】従来の車体構造用筒状部材の取付部位を示す自動車の斜視図である。
【符号の説明】
１１筒状部材
１１ａ筒状部分
１１ｂフランジ
１２中空部
１３筒状部材
３１筒状部材
３１ａ，３１ｂシワ
３２ａ筒状部分
３２ｂフランジ[0001]
[Industrial application fields]
The present invention relates to a cylindrical structural member constituting a vehicle body of an automobile, and more particularly to a method of manufacturing a cylindrical member for vehicle body structure that is curved in a two-dimensional or three-dimensional direction and has a substantially polygonal cross section. is there.
[0002]
[Prior art]
Conventionally, the body of an automobile is formed by pressing a steel plate or by combining various shapes of body members obtained by bending an extruded steel pipe, and joining the body members using spot welding or the like. In recent years, the use of a light alloy such as an aluminum alloy or a titanium alloy instead of a steel sheet has been studied in order to reduce the weight of the vehicle body.
For example, a structural member such as a front side frame member that extends rearward from the lower part of the engine room in front of the vehicle body and is connected to a structural member on the front floor of the passenger compartment, and a rear side frame member that extends rearward from the structural member of the passenger compartment rear floor and reaches the lower part of the trunk room. Needs to be a cylindrical member having a substantially constant cross-sectional shape over the entire length in the longitudinal direction.
[0003]
FIG. 9 is a perspective view of an automobile showing an attachment part of a conventional tubular member for vehicle body structure. In the figure, 1 is a vehicle body, 2 is a pair of front side frame members constituting the front of the vehicle body 1, and 3 Are a pair of rear side frame members constituting the rear right side of the vehicle body 1.
The front side frame member 2R on the front right side of the vehicle body has a front end portion 2a and a rear end portion 2c that are straight, and a portion 2b that connects these straight portions 2a and 2c is rearward so as to avoid contact with the front wheel 4. It is bent three-dimensionally downward and outward in the middle of extending. The front side frame member 2R is integrally provided with a flange 2d extending vertically upward in order to connect to a panel member such as a front wheel apron.
[0004]
Similarly, the rear side frame member 3R on the rear right side of the vehicle body has a front end portion 3a and a rear end portion 3c that are linear, and a portion 3b that connects these linear portions 3a and 3c avoids contact with the rear wheel 5. Therefore, it is bent three-dimensionally upward and toward the inside of the vehicle body in the middle of extending backward. The rear side frame member 3R is integrally provided with a pair of flanges 3d and 3e extending outward in the horizontal direction so as to be connected to a trunk floor or the like, and close to the rear wheel 5 of the flange 3d. The portion 3f is bent so as to extend vertically upward in order to connect to the rear wheel apron.
[0005]
The structural members such as the front side frame member 2 and the rear side frame member 3 can be efficiently formed by bending a square tube made of aluminum alloy extruded into a rectangular cross section having a flange by pressing or the like. Because of this, it has been attracting attention as a target part for weight reduction.
[0006]
[Problems to be solved by the invention]
As described above, structural members used in automobiles often have flanges, and their cross-sectional shapes are often polygonal.
However, for example, an aluminum alloy square tube has a low mechanical strength and rigidity unlike a steel square tube, and wrinkling due to bending is likely to occur on the wall surface of the square tube simply by bending. There was a problem. Further, when the square tube is bent, there is a problem that a desired shape cannot be obtained because the flange is not malleable and is deformed greatly. These problems are the main factors that deteriorate the quality of the vehicle body structural member that is required to have high mechanical strength and shape accuracy for welding with the panel member of the vehicle body.
[0007]
The present invention has been made in view of the above circumstances, and has a vehicle body structure having a substantially polygonal cross section curved in a two-dimensional or three-dimensional direction, such as the above-described front side frame member and rear side frame member. It is an object of the present invention to provide a method for manufacturing a tubular member for vehicle body structure that can manufacture a tubular member for a vehicle without causing problems such as wrinkles on a wall surface and deformation of a flange associated with bending.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs the following method for manufacturing a tubular member for vehicle body structure.
That is, the manufacturing method of the tubular member for vehicle body structure according to claim 1 includes a substantially polygonal cross-section tubular member having a flange integrally formed along the outer longitudinal direction and having one or more hollow portions. The extruded cylindrical member is put into a mold that is engaged with the cross-sectional shape and curved in the longitudinal direction, the flange is clamped, and the mold is clamped. A preliminary pressure is appropriately applied in the hollow portion of the cylindrical member, and the cylindrical member is curved by further increasing the pressure, and the wall surface thereof is bulged to be in close contact with the mold. .
[0009]
The method of manufacturing a tubular member for vehicle body structure according to claim 2 is an extrusion molding of a tubular member having a substantially polygonal cross section in which a flange is integrally formed along the outer longitudinal direction and has one or more hollow portions. Then, the extruded cylindrical member is bent, and the bent cylindrical member is put into a mold engaged with the bent shape and the cross-sectional shape, and the flange is clamped. It is characterized in that the pressure is appropriately applied to the inside of the cylindrical member, and the wall surface is bulged to be brought into close contact with the mold .
[0010]
The method for manufacturing a tubular member for vehicle body structure according to claim 3 is an extrusion molding of a tubular member having a substantially polygonal cross section in which a flange is integrally formed along an outer longitudinal direction and has one or more hollow portions. Then, the extruded cylindrical member is bent, and the bent cylindrical member is put into a mold that is curved in a longitudinal direction different from the bending direction and engaged in a cross-sectional shape. While holding the flange and clamping the mold, an appropriate preload is applied to the hollow portion of the cylindrical member, and the pressure is increased to bend the cylindrical member and swell its wall surface. It is made to stick out to the said metal mold | die .
[0016]
[Action]
In the method for manufacturing a tubular member for vehicle body structure according to claim 1 of the present invention, a substantially polygonal cross section in which a flange is integrally formed along an outer longitudinal direction of extrusion molding and has one or more hollow portions. The cylindrical member is inserted into a mold that is engaged with the cross-sectional shape and curved in the longitudinal direction, and is appropriately inserted into the hollow portion of the cylindrical member while holding the flange and clamping the mold. By applying a pre-load, and further increasing the pressure to bend the tubular member, and expanding the wall surface so that the wall surface is in close contact with the mold, wrinkles on the wall surface generated during bending are reduced. Stretched and disappeared. Further, when the overhanging process is performed , a cylindrical member with a flange having a two-dimensional bending shape having a complicated and substantially polygonal cross section with a high accuracy is obtained by expanding the wall surface and closely adhering to the mold.
[0017]
3. The method for manufacturing a tubular member for vehicle body structure according to claim 2, wherein the flange is integrally formed along the outer longitudinal direction of the extrusion and has a substantially polygonal cross section having one or more hollow portions. The member is bent, the cylindrical member subjected to the bending is put into a mold engaged with the bent shape and the cross-sectional shape, and held while holding the flange. By appropriately applying a pressure to the wall, the wall surface is bulged and brought into close contact with the mold, so that the wrinkles of the wall surface generated during bending are stretched and disappear. In addition, when the wall surface bulges, the flange is brought into close contact with the mold without causing a positional shift, and a highly accurate and complex two-dimensional bent tubular member having a substantially polygonal cross section is obtained.
[0018]
In the method for manufacturing a tubular member for vehicle body structure according to claim 3, the flange is integrally formed along the outer longitudinal direction subjected to the bending process , and has a substantially polygonal cross section having one or more hollow portions. The cylindrical member is placed in a mold that is curved in a longitudinal direction different from the bending direction and engaged in a cross-sectional shape, and sandwiches the flange and clamps the mold into the hollow portion of the cylindrical member. Appropriately applying a preliminary pressure, further increasing the pressure to bend the cylindrical member, and expanding the wall surface and closely contacting the mold, thereby expanding the wall surface, flange and metal mold There is no risk of misalignment between the mold and wrinkles on the wall surface during processing, and a highly accurate and complex three-dimensional bent flanged cylindrical member having a substantially polygonal cross section is obtained. It is done.
[0024]
【Example】
Hereinafter, each Example of the manufacturing method of the cylindrical member for vehicle body structures of this invention is described based on drawing.
(First embodiment)
FIG. 1 is a process diagram showing a method of manufacturing a front side frame member (a tubular member for vehicle body structure) according to an embodiment of the present invention.
First, as shown in FIG. 1 (a), the first step is an extrusion molding step in which a cylindrical member 11 made of an aluminum material is extruded, and this cylindrical member 11 is a hollow portion having a rectangular shape in the longitudinal direction. 12 having a constant thickness, and a flange having a constant thickness that is integrally provided along the longitudinal direction at the outer corner of the cylindrical portion 11a and extends linearly toward the outside. 11b.
[0025]
Next, as shown in FIG. 1B, the second step is a bending step in which the straight cylindrical member 11 extruded in the first step is bent in a vertical plane.
This bending process is performed using a processing apparatus as shown in FIGS.
The processing device 21 includes molds 22 to 24 that form dies that engage with the cross-sectional shape of the cylindrical member 11 and are curved along the longitudinal direction of the cylindrical member 11 in a vertical plane. -24 are detachably provided at both ends in the longitudinal direction, and the bases 25, 25 for fixing the both ends of the cylindrical member 11 to be bent, and the pressure in the cylindrical member 11 provided at each base 25 And an air hose 26 that loads the air.
[0026]
Here, the molds 22 to 24 are moved in advance in a direction away from each other, that is, in the plane direction of FIG. 3, and the molds 22 to 24 are kept open.
First, the both ends of the cylindrical member 11 are fixed by the caps 25, 25, the cylindrical member 11 is put into the molds 22 to 24, and the molds 22 to 24 are moved in the directions close to each other, and FIG. As shown in FIG. 3, a preliminary pressure is appropriately applied to the hollow portion 12 of the tubular member 11 by the air hose 26 while the molds 22 to 24 are clamped, and the tubular member 11 is bent by further increasing the pressure. .
[0027]
As described above, the linearly extending cylindrical member 11 is processed into a substantially S-shaped cylindrical member 13 having a flange 11b and a highly accurate rectangular shape as shown in FIG. . If both ends of the cylindrical member 13 are cut to a predetermined length, a front side frame member can be obtained. The rear side frame member can also be manufactured by the same manufacturing method.
[0028]
As described above, according to the method for manufacturing the front side frame member of the above embodiment, the cylindrical portion 11a in which the rectangular hollow portion 12 is formed in the longitudinal direction, and the outer corner portion of the cylindrical portion 11a. A cylindrical member 11 having a flange 11b erected integrally along the longitudinal direction is extruded, and the extruded cylindrical member 11 is engaged with its cross-sectional shape and curved in the longitudinal direction. It inserts in 22-24, a preliminary | backup pressure is suitably loaded in the hollow part 12 of the cylindrical member 11, tightening the metal molds 22-24, and also the pressure is increased, and the cylindrical member 11 is curved. Therefore, the wrinkles of the wall surface generated during the bending process can be extended and disappeared, and the wall surface bulges and comes into close contact with the molds 22 to 24 and has a highly accurate rectangular cross section 13. Can be obtained. Therefore, it is possible to manufacture the cylindrical member 13 that is free from defects such as wrinkles on the wall surface caused by bending.
[0029]
In addition, since the flange 11b is integrally formed on the outer surface of the tubular member 11, the flange 11b is bent so as to extend in an arbitrary direction and the bending deformation is corrected when the bending is performed. It is possible to obtain the cylindrical member 13 having the flange 11b with high accuracy.
[0030]
In addition, although the present Example demonstrated the manufacturing method of the cylindrical member 11 which has a rectangular cross section, it is not limited to the said Example, Cylindrical members of various cross-sectional shapes, for example, a hexagon, etc. Can be manufactured. Further, the cylindrical member 11 may have a configuration in which one or more ribs extending in the longitudinal direction are formed in the cylinder so as to have a plurality of hollow portions. When a plurality of ribs are formed, these ribs may be parallel to each other or cross each other.
[0031]
(Second embodiment)
FIG. 5 is a view showing a method of manufacturing a front side frame member according to the second embodiment of the present invention.
First, as shown in FIG. 5 (a), the first step is an extrusion molding step of extruding a cylindrical member 11 made of an aluminum material. Like the first embodiment, this cylindrical member 11 is A cylindrical portion 11a having a constant thickness with a rectangular hollow portion 12 formed in the longitudinal direction, and an outer corner portion of the tubular portion 11a that is integrally provided along the longitudinal direction, and straight toward the outside. Extrusion molding is performed so as to have a constant thickness flange 11b extending in a shape.
[0032]
Next, as shown in FIG. 5B, the second step is a bending step in which the straight cylindrical member 11 extruded in the first step is bent into a predetermined shape in the vertical plane.
In this bending method, the tubular member 11 is bent into a vertical plane while applying a tensile force to form the tubular member 31. For example, the tubular member 11 is processed using a bending apparatus as shown in FIG.
The bending device 41 includes a wheel-like rotary bending die 42 having a center C and provided with a groove 42 a so as to match the outer shape of the cylindrical member 11, and a clamping die lower die fixed to the rotary bending die 42. 43 and an upper mold 44, and a movable pressing mold 45 that is provided on the same axis as the lower mold 43 and the upper mold 44 and that grips the flange 11b of the cylindrical member 11 and moves from the left side to the right side in the drawing during bending. It is roughly composed.
[0033]
Here, one end of the cylindrical member 11 is sandwiched between the lower mold 43 and the upper mold 44, fixed to the rotary bending mold 42, and disposed so as to extend in the horizontal direction. Then, the flange 11 b is gripped by the movement pressing die 45. Then, a core (not shown) is inserted into the hollow portion 12 so that the cross-sectional shape of the cylindrical member 11 is not deformed.
Then, in this state, the rotary bending die 42 is slowly rotated to the right in the drawing around its center C, and the cylindrical member 11 is aligned with the radius of curvature of the center of the groove 42a of the rotating bending die 42 in the vertical plane. Bend to convex upward. Further, the bent portion that is projected downward in the vertical plane of the cylindrical member 11 is also bent using the same apparatus as described above.
[0034]
At this time, wrinkles 31a and 31b are generated in the bent portions of the cylindrical portion 11a and the flange 11b, respectively, which contribute to the occurrence of buckling. Therefore, correction processing for eliminating the wrinkles 31a and 31b is performed.
[0035]
Next, as shown in FIG. 5C, the third step is a correction processing step for eliminating the wrinkles 31a and 31b of the tubular member 31 bent in the second step.
This straightening process is performed using the processing apparatus used in the first embodiment.
Here, the molds 22 to 24 are moved in advance in a direction away from each other, that is, in the plane direction of FIG. 3 to leave the molds 22 to 24 open, and both ends of the cylindrical member 31 are connected to the caps 25 and 25. The cylindrical member 31 is put into the molds 22 to 24, and the molds 22 and 23 are moved in the xy directions so as to contact the mold 24 as shown in FIG. The wrinkles 31a and 31b of the cylindrical member 31 are extended while the molds 22 to 24 are clamped. Next, as shown in FIG. 7B, a preliminary pressure is appropriately loaded into the hollow portion 12 by the air hose 26, and the pressure is further increased to eliminate and correct the wrinkles 31a and 31b of the cylindrical member 31.
At this time, the bending deformation of the flange 11b can be corrected at the same time, and a highly accurate flange 32b can be obtained.
[0036]
Thus, the substantially S-shaped tubular member 32 having the tubular portion 32a and the flange 32b from which the wrinkles 31a and 31b have disappeared is manufactured.
If both ends of the cylindrical member 32 are cut to a predetermined length, the front side frame member can be obtained. The rear side frame member can also be manufactured by the same manufacturing method.
[0037]
As described above, according to the method of manufacturing the front side frame member of the above embodiment, the extruded cylindrical member 11 is bent, and the wrinkles 31a and 31b of the bent cylindrical member 31 are further processed. Since the correction process to eliminate is performed, the wrinkles 31a and 31b generated during the bending process can be extended and disappeared, and the wall surface bulges and closely adheres to the molds 22 to 24, and has a highly accurate rectangular shape. The cylindrical member 32 having a cross section can be obtained. Therefore, the cylindrical member 32 without defects such as wrinkles 31a and 31b can be manufactured.
[0038]
Also in this embodiment, it is possible to manufacture cylindrical members having various cross-sectional shapes, such as hexagons, without being limited to the above embodiments. Further, the cylindrical member 11 may have a configuration in which one or more ribs extending in the longitudinal direction are formed in the cylinder so as to have a plurality of hollow portions. When a plurality of ribs are formed, these ribs may be parallel to each other or cross each other.
Furthermore, the apparatus used for bending is not limited to the bending apparatus described above, and a bending apparatus suitable for the shape and size of the cylindrical member 11 may be appropriately selected from various bending apparatuses.
[0039]
(Third embodiment)
FIG. 8 is a view showing a processing apparatus used in the method for manufacturing a front side frame member of the third embodiment of the present invention to bend a cylindrical member 31 that has been two-dimensionally bent in a three-dimensional direction.
The processing device 51 includes molds 52 and 53 that are engaged with the cross-sectional shape of the cylindrical member 11 and that form a die that curves the cylindrical member 11 in a three-dimensional direction, and the longitudinal direction of the molds 52 and 53. Bases 25, 25 that are detachably provided at both ends and fix both ends of the cylindrical member 11 to be bent, and an air hose 26 that is provided at each base 25 and applies pressure to the cylindrical member 11. It is comprised by.
[0040]
Next, a description will be given of a processing step in which the cylindrical member 31 that has been two-dimensionally bent by the bending device 41 is bent in the three-dimensional direction using the processing device 51, and thereafter the wrinkles 31a and 31b are eliminated. .
Here, the molds 52 and 53 are moved in advance in a direction away from each other, and the molds 52 and 53 are opened.
First, both ends of the cylindrical member 31 are fixed by the caps 25, 25, the cylindrical member 31 is put into the molds 52, 53, and the molds 52, 53 are moved in directions close to each other. While the molds 52 and 53 are clamped, a preliminary pressure is appropriately applied to the hollow portion 12 by the air hose 26, and the cylindrical member 31 is bent in a three-dimensional direction.
Further, the pressure is increased to eliminate and correct the wrinkles 31a and 31b of the cylindrical member 31.
At this time, the bending deformation of the flange 11b can be corrected at the same time, and a highly accurate flange can be obtained.
[0041]
As described above, a cylindrical member curved in a substantially S shape in the three-dimensional direction having the cylindrical portion 32a and the flange 32b from which the wrinkles 31a and 31b have disappeared is manufactured.
If both ends of the cylindrical member are cut to a predetermined length, a front side frame member can be obtained. The rear side frame member can also be manufactured by the same manufacturing method.
[0042]
As described above, according to the method for manufacturing the front side frame member of the above embodiment, the bent cylindrical member 31 is curved in the three-dimensional direction, and thereafter the processing step of eliminating the wrinkles 31a and 31b is performed. As a result, it is possible to bend in the three-dimensional direction and extend and eliminate the wrinkles 31a and 31b generated during the bending process, thereby obtaining a highly accurate cylindrical member. Therefore, it is possible to manufacture a cylindrical member free from defects such as wrinkles 31a and 31b.
[0043]
Also in this embodiment, it is possible to manufacture various cross-sectional shapes, for example, hexagonal cylindrical members, without being limited to the above embodiments. Further, the cylindrical member 31 may have a configuration in which one or more ribs extending in the longitudinal direction are formed in the cylinder so as to have a plurality of hollow portions. When a plurality of ribs are formed, these ribs may be parallel to each other or cross each other.
[0044]
【The invention's effect】
According to the method for manufacturing a tubular member for vehicle body structure according to claim 1 of the present invention, the extruded tubular member is put into a mold that is engaged with the cross-sectional shape and curved in the longitudinal direction , While holding the flange and clamping the mold, a preliminary pressure is appropriately applied to the hollow portion of the cylindrical member, and the pressure is increased to bend the cylindrical member and bulge its wall surface. The wall surface wrinkles generated during bending can be stretched and eliminated, and the wall surface bulges when the overhanging process is performed. It is possible to obtain a cylindrical member that adheres closely to each other and has a complicated and substantially polygonal cross section. Therefore, it is possible to manufacture a flanged tubular member having a two-dimensional bent shape that is free from defects such as wrinkles on the wall surface caused by bending.
[0045]
According to the method for manufacturing a tubular member for vehicle body structure according to claim 2, the tubular member subjected to bending is put into a mold engaged with the bent shape and the cross-sectional shape, and the flange is clamped. Since the pressure is appropriately applied to the inside of the cylindrical member and the wall surface is bulged to be in close contact with the mold, wrinkles on the wall surface generated during bending can be stretched and disappeared. Moreover, when the wall surface bulges, the flange can be brought into close contact with the mold without causing a positional shift, and a cylindrical member having a highly accurate and substantially polygonal cross section can be obtained. Therefore, it is possible to manufacture a flanged tubular member having a two-dimensional bent shape that is free from defects such as wrinkles on the wall surface caused by bending.
[0046]
According to the method for manufacturing a tubular member for vehicle body structure according to claim 3, the tubular member subjected to the bending process is put into a mold that is bent in a longitudinal direction different from the bending direction and engaged in a cross-sectional shape. Then, while holding the flange and clamping the mold, an appropriate preliminary pressure is loaded into the hollow portion of the cylindrical member, and the pressure is increased to curve the cylindrical member, and the wall surface is Since it is swollen and brought into close contact with the mold, there is no risk of misalignment between the wall surface bulged during the overhanging process and between the flange and the mold, and wrinkles or the like may occur on the wall surface during processing. It is possible to obtain a three-dimensional bent tubular member with a flange having a complicated and substantially polygonal cross section with high accuracy.
[0052]
As described above, even a cylindrical structural member having a substantially polygonal cross section curved in two dimensions or three dimensions, such as a front side frame member or a rear side frame member of an automobile body, has wrinkles or the like on its wall surface. It can be manufactured without causing defects and can greatly contribute to weight reduction of the vehicle body.
[Brief description of the drawings]
FIG. 1 is a process diagram showing a method for manufacturing a front side frame member (a tubular member for vehicle body structure) according to an embodiment of the present invention.
FIG. 2 is a side view of a processing apparatus used in the method for manufacturing a front side frame member according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
FIG. 4 is a cross-sectional view showing a bulging process of the front side frame member according to the first embodiment of the present invention.
FIG. 5 is a process diagram illustrating a method for manufacturing a front side frame member according to a second embodiment of the present invention.
FIG. 6 is a front view of a bending apparatus used when bending a cylindrical member for bending according to a second embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a bulging process of a front side frame member according to a second embodiment of the present invention.
FIG. 8 is a side view of a processing apparatus used in a method for manufacturing a front side frame member according to a third embodiment of the present invention.
FIG. 9 is a perspective view of an automobile showing a mounting portion of a conventional tubular member for vehicle body structure.
[Explanation of symbols]
11 Tubular member 11a Tubular part 11b Flange 12 Hollow part 13 Tubular member 31 Tubular members 31a, 31b Wrinkle 32a Tubular part 32b Flange

Claims

A cylindrical member having a substantially polygonal cross section having a flange formed integrally along the outer longitudinal direction and having one or more hollow portions is extruded, and the extruded cylindrical member is formed into its cross sectional shape. Put into a mold that is engaged and curved in the longitudinal direction, hold the flange and clamp the mold, and appropriately apply a preliminary pressure into the hollow part of the cylindrical member, and further increase the pressure A method of manufacturing a tubular member for a vehicle body structure, characterized in that the tubular member is curved and the wall surface thereof is bulged to adhere to the mold.

A cylindrical member having a substantially polygonal cross section in which a flange is integrally formed along the outer longitudinal direction and having one or more hollow portions is extruded, and the extruded cylindrical member is bent. The cylindrical member subjected to the bending process is put into a mold engaged with the bent shape and the cross-sectional shape, held while holding the flange, and an appropriate pressure is applied to the inside of the cylindrical member. A method of manufacturing a tubular member for vehicle body structure, characterized in that the wall surface is bulged and brought into close contact with the mold.

A cylindrical member having a substantially polygonal cross section in which a flange is integrally formed along the outer longitudinal direction and having one or more hollow portions is extruded, and the extruded cylindrical member is bent. The cylindrical member subjected to the bending process is placed in a mold that is curved in a longitudinal direction different from the bending direction and engaged in a cross-sectional shape, and the flange is sandwiched and the mold is clamped while the mold is clamped. A vehicle body structure characterized in that a preliminary pressure is appropriately applied in the hollow portion of the tubular member, and the tubular member is curved by further increasing the pressure, and the wall surface of the tubular member is bulged to be in close contact with the mold. Of manufacturing a tubular member for use.