JP4051553B2

JP4051553B2 - Suspension cross member

Info

Publication number: JP4051553B2
Application number: JP2002375203A
Authority: JP
Inventors: 繁樹浜; 慎二加藤
Original assignee: Mitsubishi Motors Corp
Current assignee: Mitsubishi Motors Corp
Priority date: 2002-12-25
Filing date: 2002-12-25
Publication date: 2008-02-27
Anticipated expiration: 2022-12-25
Also published as: JP2004203240A

Description

【０００１】
【発明の属する技術分野】
本発明は、サスペンションクロスメンバに係り、詳しくは、二股に分岐して延びる両端に一対のロアアームの前側アームと後側アームとがそれぞれ連結される構成のサスペンションクロスメンバの構造に関する。
【０００２】
【関連する背景技術】
モノコック構造からなる車体では、特に入力の大きいフロントサスペンションの配設部位の強度及び剛性を増すため、車両幅方向に渡すようにしてサスペンションクロスメンバを車体下面に配設するようにしている。
サスペンションクロスメンバの左右両端には、車輪（前輪）を支持するロアアームの前側アームと後側アームとがそれぞれ連結されるため、また周辺にトランスミッション等種々の機器が配設されるため、当該左右両端は一般には分岐基端部で二股に分岐した形状を呈しており、分岐した車両前方部分に前側アームが連結部材を介して連結され、車両後方部分に後側アームが連結部材を介して連結されている。
【０００３】
そして、サスペンションクロスメンバでは、軽量化等の理由から、通常アッパメンバプレートとロアメンバプレートとを重ね合わせて周縁を接合した閉断面構造が採用されている。
また、最近では、さらなる軽量化等を図るため、両端の二股に分岐した分岐基端部近傍でアッパメンバプレートとロアメンバプレートとを接合せず乖離して開口させ、ロアアームの後側アームについては当該開口から挿入し、閉断面の内部で連結部材を設けずにアッパメンバプレートとロアメンバプレートとで直接挟み込むように連結する構造が採用されつつある。
【０００４】
両端が二股に分岐した形状のサスペンションクロスメンバにおいては、車両の制動時等においてロアアームから前側アーム及び後側アームを介して車両後方に向かう入力があると、分岐基端部近傍を中心として車両前方部分や車両後方部分を回転させようとする様々な回転力が作用する。故に、アッパメンバプレートとロアメンバプレートとを重ね合わせ且つ開口を有する構造では、このように、二股に分岐した車両前方部分と車両後方部分とに分岐基端部近傍を中心とする回転力が作用すると、大きなモーメントの作用する車両前方部分の付け根部位と車両後方部分の付け根部位とが過度の入力により曲げ変形を起こす可能性が高い。
【０００５】
そこで、例えば、上記開口を有するサスペンションクロスメンバにおいて、開口の存在により特に曲げ変形が予想される車両後方部分の付け根部位に、補強用のブラケットを接合する技術が開発されている（特許文献１参照）。
【０００６】
【特許文献１】
特開２００１−２５３２１８号公報
【０００７】
【発明が解決しようとする課題】
ところで、上記特許文献１に開示されるサスペンションクロスメンバのように、一般にはスペース等の関係からロアアームの前側アームの取付け点は分岐基端部から遠く離れる傾向にあり、これにより特に車両前方部分を回転させようとする回転力が大きく働く傾向にある。車両前方部分に大きな回転力が働くと、開口の乖離開始点にはブラケットを後方に押そうとする力が大きく働く。即ち、ロアアームに車両後方に向かう入力があり、前側アームを介して車両前方部分を後方へ回転させようとする回転力が作用すると、開口の乖離開始点にはアッパメンバプレートとロアメンバプレートとの接合を剥がそうとする大きな力が作用し、開口がさらに広がろうとする。
【０００８】
このように、開口を広げるような力が生じると、上記特許文献１に開示のサスペンションクロスメンバでは、ブラケットは、単にロアメンバプレートに接合され、開口の乖離開始点近傍でもロアメンバプレートだけに接合された構造であるため、アッパメンバプレートが自由に開口しようとし、アッパメンバプレートとロアメンバプレートとの接合が乖離開始点で剥がれ易いという問題がある。
【０００９】
この場合、ブラケットをアッパメンバプレート側にも接合することが考えられるが、上記特許文献１に開示のブラケットのように断面コ字状であっても車両幅方向内側にフランジが向いている構造では、アッパメンバプレートとロアメンバプレートとを重ねた後での接合作業は困難である。
また、上記特許文献１に開示されるように、乖離開始点から急激に開口するようになっていると、車両前方部分を後方へ回転させようとする回転力が作用したとき、開口縁が変形し易いために乖離開始点がブラケット側に移動し易く、上記問題は顕著である。
【００１０】
本発明はこのような問題点を解決するためになされたもので、その目的とするところは、アッパメンバプレートとロアメンバプレートとが二股に分岐して延びる両端の分岐基端部近傍でそれぞれ乖離して開口し且つ該開口する部分を除き閉断面を形成するよう周縁で接合されて一体に構成され、該開口から挿入されるロアアームの後側アームの支持点が上記分岐基端部より車両前後方向後側に閉断面の内部に位置して設けられたサスペンションクロスメンバにおいて、上記開口の乖離開始点での剥がれを防止したサスペンションクロスメンバを提供することにある。
【００１１】
【課題を解決するための手段】
上記した目的を達成するために、請求項１のサスペンションクロスメンバでは、アッパメンバプレートとロアメンバプレートとが車両前後方向前側の車両前方部分と後側の車両後方部分とに二股に分岐して延びる両端の分岐基端部近傍でそれぞれ乖離して開口し且つ該開口する部分を除き閉断面を形成するよう周縁で接合されて一体に構成され、車輪を支持する一対のロアアームの前側アームの支持点を前記車両前方部分に前記閉断面の外部に位置してそれぞれ有するとともに前記開口から挿入される後側アームの支持点を前記車両後方部分に前記閉断面の内部に位置してそれぞれ有し、車体下面に車両幅方向に延びて取り付けられるサスペンションクロスメンバにおいて、前記アッパメンバプレートと前記ロアメンバプレートとの間には、前記後側アームの支持点よりも車両幅方向内側に設けられ、周縁が前記開口の前記前側アーム側の乖離開始点から前記アッパメンバプレートの内面及び前記ロアメンバプレートの内面に沿い車両前後方向後側に向けて延び且つこれらアッパメンバプレートとロアメンバプレートとに接合されてなるバルクヘッドを備え、該バルクヘッドは、少なくとも前記前側アーム側の乖離開始点の近傍でそれぞれ前記アッパメンバプレートと前記ロアメンバプレートとに接合されることを特徴としている。
【００１２】
即ち、アッパメンバプレートとロアメンバプレートとの間には、二股に分岐する車両後方部分の付け根部位に、開口の前側アーム側の乖離開始点からアッパメンバプレートの内面及びロアメンバプレートの内面に沿って車両前後方向後側に延びるバルクヘッドが介装されており、当該バルクヘッドは、少なくとも前側アーム側の開口の乖離開始点の近傍でそれぞれアッパメンバプレートとロアメンバプレートとに接合されている。
【００１３】
従って、ロアアームに車両後方に向かう入力があり、前側アームを介して車両前方部分を後方へ回転させようとする回転力が作用し、開口の乖離開始点にアッパメンバプレートとロアメンバプレートとの接合を剥がそうとする大きな力が作用しても、当該乖離開始点の近傍ではバルクヘッドがそれぞれアッパメンバプレートとロアメンバプレートと接合されているため、乖離開始点においてアッパメンバプレートとロアメンバプレートとの接合が剥がれることはない。
【００１４】
また、請求項２のサスペンションクロスメンバでは、前記開口は、開口寸法が前記前側アーム側の乖離開始点から徐々に増加していることを特徴としている。従って、開口が乖離開始点から急激に開口でず、徐々に開口するので、車両前方部分を後方へ回転させようとする回転力が作用したとき、当該回転力がほぼアッパメンバプレートとロアメンバプレートに沿い伝達されて開口縁が変形し難く、故に乖離開始点がバルクヘッド側に移動し難く、乖離開始点においてアッパメンバプレートとロアメンバプレートとの接合がより一層剥がれなくなる。
【００１５】
また、請求項３のサスペンションクロスメンバでは、前記バルクヘッドの周縁には、前記前側アーム側の乖離開始点に対応する部位から所定範囲に亘り前記開口側に向けて周縁フランジが立設されており、該周縁フランジがそれぞれ前記アッパメンバプレートと前記ロアメンバプレートとに接合されることを特徴としている。
【００１６】
従って、バルクヘッドの周縁に前側アーム側の乖離開始点に対応する部位から所定範囲に亘り開口側に向けて周縁フランジが設けられていると、バルクヘッド自体の剛性が高まりアッパメンバプレートやロアメンバプレートの撓みや凹みが確実に防止されるとともに、バルクヘッドを予めアッパメンバプレートとロアメンバプレートのいずれか一方に接合しておき、後工程でアッパメンバプレートとロアメンバプレートとを重ねた場合であっても、当該重ね合わせた状態でバルクヘッドの周縁フランジが開口側に向けて延びていることになり、開口から容易に他方への接合作業を行うことが可能である。
【００１７】
また、請求項４のサスペンションクロスメンバでは、さらに、前記アッパメンバプレートと前記ロアメンバプレートとの間には、一端が前記前側アーム側の乖離開始点の近傍で前記バルクヘッドと接合され、他端が前記アッパメンバプレートの内面及び前記ロアメンバプレートの内面に沿い車両前後方向前方に向けて延び且つこれらアッパメンバプレートとロアメンバプレートと接合されてなるサポート部材を備えることを特徴としている。
【００１８】
従って、ロアアームに車両後方に向かう入力があり、前側アームを介して車両前方部分を後方へ回転させようとする回転力が作用しても、二股に分岐する車両前方部分の付け根部位に、一端がバルクヘッドに接合されるサポート部材を渡すことにより、車両前方部分の回転力がサポート部材を介して圧縮力（突張力）としてバルクヘッドに作用することになり、車両前方部分の回転が抑制されて乖離開始点に掛かる力が緩和され、乖離開始点においてアッパメンバプレートとロアメンバプレートとの接合がより一層剥がれなくなる。
【００１９】
【発明の実施の形態】
以下、本発明に係るサスペンションクロスメンバの実施形態を添付図面に基づき説明する。
図１には、本発明に係るサスペンションクロスメンバの上視図が示されており、図２には図１の矢視Ａ方向から視た本発明に係るサスペンションクロスメンバの車両幅方向左側部分の斜視図が示されている。さらに、図３には図１の矢視Ｂ方向から視た本発明に係るサスペンションクロスメンバの側面図が示され、図４には図１の矢視Ｃ方向から視た本発明に係るサスペンションクロスメンバの内部構造が示されている。
【００２０】
サスペンションクロスメンバ１は、フロントサスペンションの配設される部位の車体強度及び車体剛性を増すため、車両幅方向に渡すようにして車体下面（例えば、一対のサイドメンバ下面）に配設される部材である。故に、サスペンションクロスメンバ１の両側には、車両前方側に鋼材からなる支持部材２，３を介して一対の車体連結部材４，５がメンバ本体２０に溶接して設けられ、車両後方側に車体連結部材６，７がメンバ本体２０に溶接して設けられている。
【００２１】
車体連結部材４，５，６，７は例えば金属ワッシャからなり、サスペンションクロスメンバ１は、車体連結部材４，５，６，７にボルトを通すことによって車体下面に取り付けられる。
詳しくは、メンバ本体２０は、トランスミッション等種々の機器の配設スペース等の関係から、車両幅方向の左右両端が、車両前方部分３０，３１と車両後方部分３２，３３のように二股に分岐しており、車体連結部材４，５の支持部材２，３については車両前方部分３０，３１に、車体連結部材６，７については車両後方部分３２，３３の先端にそれぞれ溶接されている。
【００２２】
図２、図３に示すように、メンバ本体２０は、厚板鋼板からなるアッパメンバプレート２２とロアメンバプレート２３とから構成されている。詳しくは、メンバ本体２０は、アッパメンバプレート２２とロアメンバプレート２３とが周縁フランジ２４，２５において重ね合わされ、開口２７，２８の部分を除いて周縁フランジ２４，２５が互いに溶接され、アッパメンバプレート２２とロアメンバプレート２３とで閉断面を形成するように構成されている。
【００２３】
そして、車両前方部分３０，３１には、車輪ＷL，ＷRを支持するロアアーム１００，１０１の前側アーム１０２，１０３を連結するアーム連結ブラケット８，９が溶接されている。
また、図２、図３に示すように、車両後方部分３２，３３には、ロアメンバプレート２３上に位置してロアアーム１００，１０１の後側アーム１０４，１０５を連結するアーム連結孔１０，１１が設けられている。つまり、前側アーム１０２，１０３のアーム連結ブラケット８，９についてはメンバ本体２０の外部に設けられている一方、後側アーム１０４，１０５のアーム連結孔１０，１１については、アッパメンバプレート２２とロアメンバプレート２３からなる閉断面の内部に設けられている。即ち、後側アーム１０４，１０５については、上記開口２７，２８からアッパメンバプレート２２とロアメンバプレート２３からなる閉断面の内部に挿入されてアーム連結孔１０，１１においてメンバ本体２０と連結される。
【００２４】
開口２７，２８は、二股に分岐した車両前方部分３０，３１と車両後方部分３２，３３の分岐基端部Ｐ近傍（図１中○で囲った範囲）から車両後方部分３２，３３の先端に向けて周縁フランジ２４，２５が乖離するようにして形成されている。つまり、メンバ本体２０は、分岐基端部Ｐ近傍に位置する周縁フランジ２４と周縁フランジ２５との乖離開始点Ｇから車両後方部分３２，３３の先端の車体連結部材６，７近傍までの間において開口している。
【００２５】
なお、開口２７，２８は、乖離開始点Ｇから徐々に開口寸法が大きくなるように傾斜面を有して開口している。
一方、アッパメンバプレート２２とロアメンバプレート２３間の後側アーム１０４，１０５の連結点であるアーム連結孔１０，１１よりも車両幅方向内側には、前端４１が上記乖離開始点Ｇに位置し、周縁が当該乖離開始点Ｇからアッパメンバプレート２２の内面及びロアメンバプレート２３の内面に沿って車両前後方向後側に向けて延び、後端４２がメンバ本体２０の後壁３５と当接するようにして厚板鋼板製のバルクヘッド４０，４０がそれぞれ介装されている。
【００２６】
つまり、車両後方部分３２，３３の付け根部位にバルクヘッド４０，４０が渡されている。
詳しくは、バルクヘッド４０には、後端４２を除き、乖離開始点Ｇに対応する前端４１からアッパメンバプレート２２及びロアメンバプレート２３に沿うように連続し且つ開口２７，２８に向けて周縁フランジ４３が形成されており、バルクヘッド４０は、前端４１に対応する当該周縁フランジ４３の先端４１ａが上記乖離開始点Ｇに位置するように設けられている。
【００２７】
バルクヘッド４０の後端４２はメンバ本体２０の後壁３５に溶接され、周縁フランジ４３は所定位置においてアッパメンバプレート２２とロアメンバプレート２３とにそれぞれ溶接されている。詳しくは、周縁フランジ４３は、乖離開始点Ｇ近傍の傾斜面においてそれぞれアッパメンバプレート２２とロアメンバプレート２３とに確実に溶接され、後端４２においてメンバ本体２０の後壁３５に確実に溶接され、その他任意位置でアッパメンバプレート２２とロアメンバプレート２３とに溶接されている。
【００２８】
このようにバルクヘッド４０が乖離開始点Ｇからアッパメンバプレート２２の内面及びロアメンバプレート２３の内面に沿って車両前後方向後側に向けて延び、アッパメンバプレート２２とロアメンバプレート２３に溶接されていると、分岐基端部Ｐ近傍とメンバ本体２０の後壁３５の内面との間、即ち車両後方部分３２，３３の付け根部位が補強され、剛性が向上することになり、図１に白抜き矢印で示すように車輪ＷL，ＷRから入力Ｆが作用し、当該入力Ｆの分力がロアアーム１００，１０１の後側アーム１０４，１０５を介して車両後方部分３２，３３に作用しても、当該車両後方部分３２，３３の変形が防止される。
【００２９】
また、バルクヘッド４０の周縁には、乖離開始点Ｇに対応する前端４１からアッパメンバプレート２２及びロアメンバプレート２３に沿うように連続して周縁フランジ４３が形成されているので、バルクヘッド４０の剛性が高くなっており、メンバ本体２０に車両上下方向で力が作用したとしても、アッパメンバプレート２２やロアメンバプレート２３が撓んだり凹んだりすることが確実に防止される。
【００３０】
さらに、入力Ｆにより、前側アーム１０２，１０３を介して車両前方部分３０，３１に矢印で示すような分力、即ち回転力Ｆ’が分岐基端部Ｐ近傍回りで生じると、開口２７，２８の乖離開始点Ｇにはバルクヘッド４０を後方に押そうとする力が働き、当該乖離開始点Ｇ近傍における周縁フランジ２４，２５の溶接、即ちアッパメンバプレート２２とロアメンバプレート２３との溶接を剥がそうとする大きな力が作用することになるが、バルクヘッド４０は、乖離開始点Ｇ近傍においてそれぞれアッパメンバプレート２２とロアメンバプレート２３とに確実に溶接されているため、開口２７，２８の拡大が防止され、乖離開始点Ｇ近傍における当該アッパメンバプレート２２とロアメンバプレート２３との溶接が剥がれることがない。
【００３１】
特に、開口２７，２８は、傾斜面を有して開口寸法が乖離開始点Ｇから徐々に増加しており、車両前方部分３０，３１に回転力Ｆ’が作用したとき、当該回転力Ｆ’はほぼアッパメンバプレート２２とロアメンバプレート２３とに沿い伝達され、開口縁は変形し難く、即ち乖離開始点Gがバルクヘッド４０側に移動し難くなっているため、より一層乖離開始点Ｇ近傍における当該アッパメンバプレート２２とロアメンバプレート２３との溶接が剥がれることがない。なお、傾斜面の傾斜角はできるだけ緩やかな方がよいが、スペースの制約を受けるため、適当な角度に設定されている。
【００３２】
なお、このように開口２７，２８が傾斜面を有して徐々に開口していることでバルクヘッド４０の前端４１は楔状であり、アッパメンバプレート２２とロアメンバプレート２３との溶接を剥がし易い形状とも考えられるが、このように開口２７，２８が傾斜面を有していることでメンバ本体２０自体の剛性及び強度は高く、また上述したように、バルクヘッド４０は、乖離開始点Ｇ近傍においてそれぞれアッパメンバプレート２２とロアメンバプレート２３とに確実に溶接されているため、乖離開始点Ｇ近傍における当該アッパメンバプレート２２とロアメンバプレート２３との溶接が剥がれることはない。
【００３３】
ところで、製造工程では、バルクヘッド４０は、例えば、アッパメンバプレート２２に沿う周縁フランジ４３と後端４２とが予め溶接されてアッパメンバプレート２２に取り付けられ、後工程で、当該バルクヘッド４０の取付けらたアッパメンバプレート２２にロアメンバプレート２３を重ねて周縁フランジ２４，２５を溶接する際に、同時にロアメンバプレート２３に沿う周縁フランジ４３についても併せてロアメンバプレート２３に溶接される。
【００３４】
詳しくは、周縁フランジ４３をロアメンバプレート２３に溶接する際には、ロアメンバプレート２３に沿う周縁フランジ４３のうち開口２７，２８から溶接トーチを挿入可能な先端４１ａ近傍の溶接部位については開口２７，２８側から溶接を行い、溶接トーチを挿入できない後端４２寄りの溶接部位についてはロアメンバプレート２３の外側からスロット溶接（或いはプラグ溶接）を行う。
【００３５】
即ち、バルクヘッド４０は、周縁フランジ４３が開口２７，２８側に向けて延びていることで、アッパメンバプレート２２にロアメンバプレート２３を重ねた状態であっても、溶接作業が容易であり、これによりバルクヘッド４０を乖離開始点Ｇ近傍でアッパメンバプレート２２のみならずロアメンバプレート２３に確実に溶接することができる。このことは、逆にバルクヘッド４０をロアメンバプレート２３に先付けする場合も同様である。
【００３６】
また、アッパメンバプレート２２とロアメンバプレート２３間には、さらに、図４に示すように前端５１が乖離開始点Gの近傍でバルクヘッド４０，４０と溶接され、周縁がアッパメンバプレート２２の内面及びロアメンバプレート２３の内面に沿って車両前後方向前側に向けて延び且つ後端５２がメンバ本体２０の前壁３４に溶接されるようにして厚板鋼板製のサポート部材５０，５０がそれぞれ介装されている。
【００３７】
つまり、車両前方部分３０，３１の付け根部位にサポート部材５０，５０がバルクヘッド４０，４０から連続するように渡されている。
なお、サポート部材５０についても、予め前端５１がバルクヘッド４０に溶接されるとともに周縁がアッパメンバプレート２２に溶接されて先付けされ、後工程でフランジ５３，５４がロアメンバプレート２３に外側からスロット溶接（或いはプラグ溶接）される。
【００３８】
このように、サポート部材５０が配設されていると、ロアアーム１００，１０１に上記入力Ｆがあり、前側アーム１０２，１０３を介して車両前方部分３０，３１に上記回転力Ｆ’が生じても、回転力Ｆ’がサポート部材５０を介して圧縮力（突張力）としてバルクヘッド４０に作用することになり、車両前方部分３０，３１の回転が抑制されて乖離開始点Ｇに掛かる力が緩和され、乖離開始点Ｇにおいてアッパメンバプレート２２とロアメンバプレート２３との溶接がより一層剥がれなくなる。
【００３９】
以上で本発明に係るサスペンションクロスメンバの実施形態についての説明を終えるが、実施形態は上記実施形態に限られるものではない。
例えば、上記実施形態では、バルクヘッド４０とサポート部材５０とを別体としているが、可能であればこれらは一体であってもよい。
【００４０】
【発明の効果】
以上詳細に説明したように、本発明の請求項１のサスペンションクロスメンバによれば、アッパメンバプレートとロアメンバプレートとの間には、二股に分岐する車両後方部分の付け根部位に、開口の前側アーム側の乖離開始点からアッパメンバプレートの内面及びロアメンバプレートの内面に沿って車両前後方向後側に延びるバルクヘッドが介装されており、当該バルクヘッドは、少なくとも前側アーム側の開口の乖離開始点の近傍でそれぞれアッパメンバプレートとロアメンバプレートとに接合されているので、ロアアームに車両後方に向かう入力があり、前側アームを介して車両前方部分を後方へ回転させようとする回転力が作用し、開口の乖離開始点にアッパメンバプレートとロアメンバプレートとの接合を剥がそうとする大きな力が作用しても、乖離開始点におけるアッパメンバプレートとロアメンバプレートの接合の剥がれを確実に防止できる。
【００４１】
また、請求項２のサスペンションクロスメンバによれば、開口が乖離開始点から急激に開口でず、徐々に開口するので、車両前方部分を後方へ回転させようとする回転力が作用したとき、当該回転力をほぼアッパメンバプレートとロアメンバプレートに沿い伝達させて開口縁を変形し難く、乖離開始点がバルクヘッド側に移動し難くでき、乖離開始点におけるアッパメンバプレートとロアメンバプレートの接合の剥がれをより一層確実に防止できる。
【００４２】
また、請求項３のサスペンションクロスメンバによれば、バルクヘッドの周縁に前側アーム側の乖離開始点に対応する部位から所定範囲に亘り開口側に向けて周縁フランジが設けられているので、バルクヘッド自体の剛性を高めてアッパメンバプレートやロアメンバプレートの撓みや凹みを確実に防止することができるし、バルクヘッドを予めアッパメンバプレートとロアメンバプレートのいずれか一方に接合しておき、後工程でアッパメンバプレートとロアメンバプレートとを重ねた場合であっても、開口から容易に他方への接合作業を行うことができる。
【００４３】
また、請求項４のサスペンションクロスメンバによれば、二股に分岐する車両前方部分の付け根部位に、一端がバルクヘッドに接合されるサポート部材を渡すようにしたので、ロアアームに車両後方に向かう入力があり、前側アームを介して車両前方部分を後方へ回転させようとする回転力が作用しても、当該回転力がサポート部材を介して圧縮力（突張力）としてバルクヘッドに作用することになり、車両前方部分の回転が抑制されて乖離開始点に掛かる力が緩和され、乖離開始点におけるアッパメンバプレートとロアメンバプレートの接合の剥がれをより一層確実に防止できる。
【図面の簡単な説明】
【図１】本発明に係るサスペンションクロスメンバの上視図である。
【図２】図１の矢視Ａ方向から視た本発明に係るサスペンションクロスメンバの車両幅方向左側部分の斜視図である。
【図３】図１の矢視Ｂ方向から視た本発明に係るサスペンションクロスメンバの側面図である。
【図４】図１の矢視Ｃ方向から視た本発明に係るサスペンションクロスメンバの内部構造図である。
【符号の説明】
１サスペンションクロスメンバ
８，９アーム連結ブラケット
１０，１１アーム連結孔
２０メンバ本体
２２アッパメンバプレート
２３ロアメンバプレート
２４，２５周縁フランジ
２７，２８開口
３０，３１車両前方部分
３２，３３車両後方部分
４０バルクヘッド
４１前端
４３周縁フランジ
４１ａ先端
５０サポート部材
１００，１０１ロアアーム
Ｇ乖離開始点
Ｐ分岐基端部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a suspension cross member, and more particularly to a structure of a suspension cross member having a structure in which a front arm and a rear arm of a pair of lower arms are respectively connected to both ends of a bifurcated branch.
[0002]
[Related background]
In a vehicle body having a monocoque structure, the suspension cross member is disposed on the lower surface of the vehicle body so as to pass in the vehicle width direction in order to increase the strength and rigidity of the portion where the front suspension having a large input is particularly large.
Since the front and rear arms of the lower arm that supports the wheels (front wheels) are respectively connected to the left and right ends of the suspension cross member, and because various devices such as a transmission are arranged in the periphery, the left and right ends Generally has a bifurcated shape at the branch base end, the front arm is connected to the branched vehicle front portion via a connecting member, and the rear arm is connected to the vehicle rear portion via a connecting member. ing.
[0003]
The suspension cross member generally employs a closed cross-sectional structure in which the upper member plate and the lower member plate are overlapped and joined at the periphery for reasons such as weight reduction.
Also, recently, in order to further reduce weight, etc., the upper member plate and the lower member plate are opened apart from each other in the vicinity of the branch base end branching into two branches at both ends. A structure has been adopted which is inserted through the opening and connected so as to be directly sandwiched between the upper member plate and the lower member plate without providing a connecting member inside the closed cross section.
[0004]
For suspension cross members with both ends bifurcated, if there is an input from the lower arm to the rear of the vehicle via the front arm and rear arm during braking of the vehicle, the front of the vehicle centering on the vicinity of the branch base end Various rotational forces act to rotate the part and the vehicle rear part. Therefore, in the structure in which the upper member plate and the lower member plate are overlapped with each other and the opening is provided, the rotational force centering around the branch base end portion acts on the vehicle front portion and the vehicle rear portion branched in this way. Then, there is a high possibility that the base part of the front part of the vehicle on which a large moment acts and the base part of the rear part of the vehicle cause bending deformation due to excessive input.
[0005]
Therefore, for example, in a suspension cross member having the above-described opening, a technique has been developed in which a reinforcing bracket is joined to a base portion of a vehicle rear portion where bending deformation is expected due to the presence of the opening (see Patent Document 1). ).
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-253218
[Problems to be solved by the invention]
By the way, as in the suspension cross member disclosed in Patent Document 1, generally, the attachment point of the front arm of the lower arm tends to be far away from the branch base end due to space and the like. There is a tendency for the rotational force to rotate to work greatly. When a large rotational force acts on the front portion of the vehicle, a force that pushes the bracket backward acts greatly on the opening start point of the opening. That is, when there is an input to the lower arm toward the rear of the vehicle and a rotational force is applied to rotate the front portion of the vehicle rearward via the front arm, the opening separation point between the upper member plate and the lower member plate A large force acts to peel off the joint and the opening is further widened.
[0008]
As described above, when a force that widens the opening is generated, in the suspension cross member disclosed in Patent Document 1, the bracket is simply joined to the lower member plate, and even to the lower member plate even near the opening start point of the opening. Due to this structure, there is a problem that the upper member plate tends to open freely, and the joining between the upper member plate and the lower member plate is easily peeled off at the start of the separation.
[0009]
In this case, it is conceivable that the bracket is also joined to the upper member plate side. However, in the structure in which the flange faces inward in the vehicle width direction even when the cross section is U-shaped like the bracket disclosed in Patent Document 1 above. The joining work after the upper member plate and the lower member plate are overlapped is difficult.
Further, as disclosed in the above-mentioned Patent Document 1, when the opening is abruptly opened from the departure point, the opening edge is deformed when a rotational force is applied to rotate the vehicle front portion backward. Therefore, the above-mentioned problem is remarkable because the deviation start point easily moves to the bracket side.
[0010]
The present invention has been made to solve such problems. The object of the present invention is to divide the upper member plate and the lower member plate in the vicinity of the branch base end portions at both ends extending in a bifurcated manner. The lower arm inserted into the opening is integrally formed by joining at the periphery so as to form an opening and a closed cross section except for the opening, and the support point of the rear arm of the lower arm inserted from the opening is An object of the present invention is to provide a suspension cross member that is prevented from being peeled off at the opening start point of the above-described opening in a suspension cross member that is provided on the rear side in the closed cross section.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, in the suspension cross member according to claim 1, the upper member plate and the lower member plate extend in a bifurcated manner into a vehicle front portion on the front side in the vehicle front-rear direction and a vehicle rear portion on the rear side. The supporting points of the front arms of the pair of lower arms that support the wheels are integrally formed by opening at a distance from each other in the vicinity of the branch base end portions at both ends and joining the peripheral edges so as to form a closed cross section except for the opening portions. At the front portion of the vehicle and positioned outside the closed section, and has a support point for a rear arm inserted from the opening at the rear portion of the vehicle and positioned inside the closed section. In the suspension cross member attached to the lower surface extending in the vehicle width direction, between the upper member plate and the lower member plate, It is provided in the vehicle width direction inner side than the support point of the rear arm, and the periphery of the rear side in the vehicle front-rear direction is along the inner surface of the upper member plate and the inner surface of the lower member plate from the separation start point of the opening on the front arm side. A bulkhead extending toward the side and joined to the upper member plate and the lower member plate, the bulkhead at least in the vicinity of the separation start point on the front arm side, respectively. It is characterized by being joined to a member plate.
[0012]
That is, between the upper member plate and the lower member plate, along the inner surface of the upper member plate and the inner surface of the lower member plate, at the base portion of the rear part of the vehicle that bifurcates, from the separation start point on the front arm side of the opening. A bulkhead extending rearward in the vehicle front-rear direction is interposed, and the bulkhead is joined to the upper member plate and the lower member plate at least in the vicinity of the departure start point of the opening on the front arm side.
[0013]
Therefore, there is an input to the lower arm toward the rear of the vehicle, and a rotational force is exerted to rotate the front portion of the vehicle rearward via the front arm, and the upper member plate and the lower member plate are joined at the opening separation start point. Even if a large force is applied to peel off the bulkhead, the bulkhead is joined to the upper member plate and the lower member plate in the vicinity of the separation start point, so the upper member plate and the lower member plate The joint is not peeled off.
[0014]
In the suspension cross member according to claim 2, the opening size of the opening gradually increases from a departure start point on the front arm side. Accordingly, the opening is not suddenly opened from the separation start point, but gradually opens. Therefore, when a rotational force is applied to rotate the front portion of the vehicle backward, the rotational force is almost equal to the upper member plate and the lower member plate. Therefore, the opening edge is not easily deformed, and hence the separation start point is difficult to move to the bulkhead side, and the joining between the upper member plate and the lower member plate is further prevented from peeling at the separation start point.
[0015]
In the suspension cross member according to claim 3, a peripheral flange is erected on the peripheral edge of the bulkhead from the portion corresponding to the deviation start point on the front arm side toward the opening side over a predetermined range. The peripheral flanges are respectively joined to the upper member plate and the lower member plate.
[0016]
Therefore, if a peripheral flange is provided on the periphery of the bulkhead from the portion corresponding to the start point of the front arm side divergence toward the opening side over the predetermined range, the rigidity of the bulkhead itself is increased and the upper member plate or lower member is increased. The plate is reliably prevented from bending or denting, and the bulkhead is joined to either the upper member plate or the lower member plate in advance, and the upper member plate and the lower member plate are stacked in a later process. Even in this case, the peripheral flange of the bulkhead extends toward the opening side in the superposed state, and it is possible to easily perform the joining operation from the opening to the other.
[0017]
In the suspension cross member according to claim 4, further, one end is joined between the upper member plate and the lower member plate near the front arm side in the vicinity of the divergence start point and the other end. Includes a support member that extends forward in the vehicle front-rear direction along the inner surface of the upper member plate and the inner surface of the lower member plate, and is joined to the upper member plate and the lower member plate.
[0018]
Therefore, even if there is an input to the lower arm toward the rear of the vehicle and a rotational force is applied to rotate the front portion of the vehicle rearward via the front arm, one end is located at the base portion of the front portion of the vehicle that bifurcates. By passing the support member joined to the bulkhead, the rotational force of the vehicle front portion acts on the bulkhead as a compressive force (projection tension) via the support member, and the rotation of the vehicle front portion is suppressed. The force applied to the separation start point is relieved, and the upper member plate and the lower member plate are not further separated at the separation start point.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a suspension cross member according to the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows a top view of a suspension cross member according to the present invention, and FIG. 2 shows a left side portion of the suspension cross member according to the present invention as viewed from the direction of arrow A in FIG. A perspective view is shown. 3 shows a side view of the suspension cross member according to the present invention as viewed from the direction of arrow B in FIG. 1, and FIG. 4 shows the suspension cross according to the present invention as viewed from the direction of arrow C in FIG. The internal structure of the member is shown.
[0020]
The suspension cross member 1 is a member disposed on the lower surface of the vehicle body (for example, the lower surfaces of a pair of side members) so as to pass in the vehicle width direction in order to increase the vehicle body strength and the vehicle body rigidity of the portion where the front suspension is disposed. is there. Therefore, on both sides of the suspension cross member 1, a pair of vehicle body connecting members 4, 5 are welded to the member main body 20 via support members 2, 3 made of steel on the vehicle front side, and the vehicle body on the vehicle rear side. The connecting members 6 and 7 are provided by welding to the member main body 20.
[0021]
The vehicle body connecting members 4, 5, 6, and 7 are made of, for example, metal washers, and the suspension cross member 1 is attached to the lower surface of the vehicle body by passing bolts through the vehicle body connecting members 4, 5, 6, and 7.
Specifically, the member main body 20 is bifurcated at both the left and right ends in the vehicle width direction like the vehicle front portions 30 and 31 and the vehicle rear portions 32 and 33 due to the arrangement space of various devices such as a transmission. The support members 2 and 3 of the vehicle body connection members 4 and 5 are welded to the vehicle front portions 30 and 31, and the vehicle body connection members 6 and 7 are welded to the tips of the vehicle rear portions 32 and 33, respectively.
[0022]
As shown in FIGS. 2 and 3, the member main body 20 is composed of an upper member plate 22 and a lower member plate 23 made of thick steel plates. Specifically, in the member main body 20, the upper member plate 22 and the lower member plate 23 are overlapped at the peripheral flanges 24 and 25, and the peripheral flanges 24 and 25 are welded to each other except for the openings 27 and 28. 22 and the lower member plate 23 form a closed cross section.
[0023]
Arm connecting brackets 8 and 9 for connecting the front arms 102 and 103 of the lower arms 100 and 101 for supporting the wheels WL and WR are welded to the vehicle front portions 30 and 31.
As shown in FIGS. 2 and 3, arm connecting holes 10 and 11 for connecting the rear arms 104 and 105 of the lower arms 100 and 101 located on the lower member plate 23 are provided in the vehicle rear portions 32 and 33. Is provided. That is, the arm connection brackets 8 and 9 of the front arms 102 and 103 are provided outside the member main body 20, while the arm connection holes 10 and 11 of the rear arms 104 and 105 are connected to the upper member plate 22 and the lower members. The member plate 23 is provided inside a closed cross section. That is, the rear arms 104 and 105 are inserted into the closed cross section formed by the upper member plate 22 and the lower member plate 23 through the openings 27 and 28 and connected to the member main body 20 at the arm connecting holes 10 and 11. .
[0024]
The openings 27 and 28 are formed at the front ends of the vehicle rear portions 32 and 33 from the vicinity of the branch base end portion P of the vehicle front portions 30 and 31 and the vehicle rear portions 32 and 33 bifurcated into a bifurcated portion (a range surrounded by a circle in FIG. 1). The peripheral flanges 24 and 25 are formed so as to be separated from each other. That is, the member main body 20 is located between the start point G of the separation between the peripheral flange 24 and the peripheral flange 25 located in the vicinity of the branch base end portion P and the vicinity of the vehicle body connecting members 6 and 7 at the distal ends of the vehicle rear portions 32 and 33. It is open.
[0025]
The openings 27 and 28 have an inclined surface so that the opening size gradually increases from the deviation start point G.
On the other hand, the front end 41 is positioned at the above-described separation start point G on the inner side in the vehicle width direction than the arm connection holes 10 and 11 that are connection points of the rear arms 104 and 105 between the upper member plate 22 and the lower member plate 23. The peripheral edge extends from the separation start point G along the inner surface of the upper member plate 22 and the inner surface of the lower member plate 23 toward the rear side in the vehicle front-rear direction, and the rear end 42 contacts the rear wall 35 of the member body 20. Then, bulkheads 40, 40 made of thick steel plates are respectively interposed.
[0026]
That is, the bulkheads 40 and 40 are passed to the base portions of the vehicle rear portions 32 and 33.
Specifically, the bulkhead 40 has a peripheral flange that is continuous from the front end 41 corresponding to the departure start point G along the upper member plate 22 and the lower member plate 23 except for the rear end 42 and toward the openings 27 and 28. 43 is formed, and the bulkhead 40 is provided such that the front end 41a of the peripheral flange 43 corresponding to the front end 41 is located at the deviation start point G.
[0027]
The rear end 42 of the bulkhead 40 is welded to the rear wall 35 of the member main body 20, and the peripheral flange 43 is welded to the upper member plate 22 and the lower member plate 23 at predetermined positions. Specifically, the peripheral flange 43 is reliably welded to the upper member plate 22 and the lower member plate 23 on the inclined surface in the vicinity of the separation start point G, and is reliably welded to the rear wall 35 of the member body 20 at the rear end 42. In addition, it is welded to the upper member plate 22 and the lower member plate 23 at other arbitrary positions.
[0028]
Thus, the bulkhead 40 extends from the separation start point G along the inner surface of the upper member plate 22 and the inner surface of the lower member plate 23 toward the rear side in the vehicle front-rear direction, and is welded to the upper member plate 22 and the lower member plate 23. As a result, the portion between the vicinity of the branch base end portion P and the inner surface of the rear wall 35 of the member main body 20, that is, the root portion of the vehicle rear portions 32 and 33 is reinforced, and the rigidity is improved. Even if the input F acts from the wheels WL and WR as indicated by the extraction arrows and the component force of the input F acts on the vehicle rear portions 32 and 33 via the rear arms 104 and 105 of the lower arms 100 and 101, The deformation of the vehicle rear portions 32 and 33 is prevented.
[0029]
Further, since the peripheral flange 43 is continuously formed along the upper member plate 22 and the lower member plate 23 from the front end 41 corresponding to the separation start point G on the peripheral edge of the bulkhead 40, Even if a force acts on the member body 20 in the vertical direction of the vehicle, the upper member plate 22 and the lower member plate 23 are reliably prevented from being bent or recessed.
[0030]
Further, when a component force as indicated by an arrow, that is, a rotational force F ′, is generated around the branch base end portion P by the input F through the front arms 102 and 103 to the vehicle front portions 30 and 31, the openings 27 and 28 are generated. At this divergence start point G, a force that pushes the bulkhead 40 backward acts, and welding of the peripheral flanges 24 and 25 in the vicinity of the divergence start point G, that is, welding of the upper member plate 22 and the lower member plate 23 is performed. Although a large force to be peeled acts, the bulkhead 40 is reliably welded to the upper member plate 22 and the lower member plate 23 in the vicinity of the separation start point G. The expansion is prevented, and the welding between the upper member plate 22 and the lower member plate 23 in the vicinity of the separation start point G is not peeled off.
[0031]
In particular, the openings 27 and 28 have inclined surfaces, and the opening dimensions gradually increase from the departure start point G. When the rotational force F ′ acts on the vehicle front portions 30 and 31, the rotational force F ′ Is transmitted substantially along the upper member plate 22 and the lower member plate 23, and the opening edge is not easily deformed, that is, the separation start point G is difficult to move to the bulkhead 40 side. The upper member plate 22 and the lower member plate 23 are not peeled off. The inclination angle of the inclined surface is preferably as gentle as possible, but is set to an appropriate angle because of space limitations.
[0032]
Since the openings 27 and 28 are gradually opened with inclined surfaces in this way, the front end 41 of the bulkhead 40 is wedge-shaped, and the welding of the upper member plate 22 and the lower member plate 23 can be easily peeled off. Although the shape may be considered, the openings 27 and 28 have the inclined surfaces as described above, so that the member body 20 itself has high rigidity and strength. As described above, the bulkhead 40 is in the vicinity of the separation start point G. In FIG. 2, since the upper member plate 22 and the lower member plate 23 are securely welded to each other, the welding of the upper member plate 22 and the lower member plate 23 in the vicinity of the separation start point G is not peeled off.
[0033]
By the way, in the manufacturing process, for example, the peripheral flange 43 and the rear end 42 along the upper member plate 22 are pre-welded to the bulkhead 40 and attached to the upper member plate 22. When the lower member plate 23 is overlapped on the upper member plate 22 and the peripheral flanges 24 and 25 are welded, the peripheral flange 43 along the lower member plate 23 is also welded to the lower member plate 23 at the same time.
[0034]
Specifically, when the peripheral flange 43 is welded to the lower member plate 23, the welded portion in the vicinity of the tip 41a into which the welding torch can be inserted from the openings 27 and 28 in the peripheral flange 43 along the lower member plate 23 is opened. , 28 is welded from the outer side of the lower member plate 23 (or plug welding) from the outside of the lower member plate 23 for the welded portion near the rear end 42 where the welding torch cannot be inserted.
[0035]
That is, in the bulkhead 40, the peripheral flange 43 extends toward the openings 27 and 28, so that the welding operation is easy even when the lower member plate 23 is overlapped with the upper member plate 22. Thus, the bulkhead 40 can be reliably welded not only to the upper member plate 22 but also to the lower member plate 23 in the vicinity of the separation start point G. The same applies to the case where the bulkhead 40 is attached to the lower member plate 23 in reverse.
[0036]
Further, between the upper member plate 22 and the lower member plate 23, as shown in FIG. 4, the front end 51 is welded to the bulkheads 40 and 40 in the vicinity of the separation start point G, and the peripheral edge is the inner surface of the upper member plate 22. And support members 50 and 50 made of thick steel plates are provided so as to extend along the inner surface of the lower member plate 23 toward the front side in the vehicle front-rear direction and the rear end 52 is welded to the front wall 34 of the member body 20. It is disguised.
[0037]
That is, the support members 50, 50 are passed from the bulkheads 40, 40 to the base portions of the vehicle front portions 30, 31.
Note that the front end 51 of the support member 50 is also welded to the bulkhead 40 in advance and the peripheral edge is welded to the upper member plate 22 in advance, and the flanges 53 and 54 are slot welded to the lower member plate 23 from the outside in a later process. (Or plug welding).
[0038]
Thus, when the support member 50 is disposed, the lower arm 100, 101 has the input F, and even if the rotational force F ′ is generated in the vehicle front portions 30, 31 via the front arms 102, 103. The rotational force F ′ acts on the bulkhead 40 as a compressive force (impact tension) via the support member 50, and the rotation of the vehicle front portions 30 and 31 is suppressed and the force applied to the separation start point G is reduced. Thus, at the separation start point G, the welding of the upper member plate 22 and the lower member plate 23 is further prevented from peeling off.
[0039]
This is the end of the description of the embodiment of the suspension cross member according to the present invention, but the embodiment is not limited to the above embodiment.
For example, in the above embodiment, the bulkhead 40 and the support member 50 are separated, but they may be integrated if possible.
[0040]
【The invention's effect】
As described above in detail, according to the suspension cross member of claim 1 of the present invention, the front portion of the opening is formed between the upper member plate and the lower member plate at the base portion of the rear portion of the vehicle that bifurcates. A bulkhead extending from the arm side separation start point to the rear side in the vehicle longitudinal direction along the inner surface of the upper member plate and the inner surface of the lower member plate is interposed, and the bulkhead has at least a separation of the opening on the front arm side. Since the upper member plate and the lower member plate are joined to each other in the vicinity of the starting point, there is an input to the lower arm toward the rear of the vehicle, and a rotational force for rotating the front portion of the vehicle rearward through the front arm is generated. A large force acting to peel off the connection between the upper member plate and the lower member plate at the opening separation start point Also act, peeling can be reliably prevented in the bonding of the upper member plate and lower member plate in the offset start point.
[0041]
Further, according to the suspension cross member of claim 2, the opening is not suddenly opened from the starting point of divergence, but gradually opens. Therefore, when a rotational force is applied to rotate the vehicle front portion backward, Rotational force is transmitted almost along the upper member plate and the lower member plate, making it difficult to deform the opening edge, making it difficult for the separation start point to move to the bulkhead side, and for joining the upper member plate and the lower member plate at the separation start point. Peeling can be more reliably prevented.
[0042]
According to the suspension cross member of claim 3, since the peripheral flange is provided on the peripheral edge of the bulkhead from the portion corresponding to the start point of the front arm side divergence toward the opening side over a predetermined range, the bulkhead The rigidity of the upper member plate and the lower member plate can be reliably prevented from being bent and dents, and the bulkhead is joined to either the upper member plate or the lower member plate in advance. Even when the upper member plate and the lower member plate are overlapped with each other, the joining operation from the opening to the other can be easily performed.
[0043]
According to the suspension cross member of claim 4, since the support member whose one end is joined to the bulkhead is passed to the base portion of the front portion of the vehicle that bifurcates, the input toward the rear of the vehicle is input to the lower arm. Yes, even if a rotational force is applied to rotate the front part of the vehicle rearward via the front arm, the rotational force acts on the bulkhead as a compressive force (impact tension) via the support member. Further, the force applied to the departure start point is reduced by suppressing the rotation of the front portion of the vehicle, and the separation of the upper member plate and the lower member plate at the departure start point can be more reliably prevented.
[Brief description of the drawings]
FIG. 1 is a top view of a suspension cross member according to the present invention.
FIG. 2 is a perspective view of a left side portion in the vehicle width direction of a suspension cross member according to the present invention as viewed from the direction of arrow A in FIG.
FIG. 3 is a side view of the suspension cross member according to the present invention as viewed from the direction of arrow B in FIG. 1;
4 is an internal structural view of a suspension cross member according to the present invention as viewed from the direction of arrow C in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Suspension cross member 8, 9 Arm connection bracket 10, 11 Arm connection hole 20 Member main body 22 Upper member plate 23 Lower member plate 24, 25 Peripheral flange 27, 28 Opening 30, 31 Vehicle front part 32, 33 Vehicle rear part 40 Bulk Head 41 Front end 43 Peripheral flange 41a Tip 50 Support member 100, 101 Lower arm G Departure start point P Branch base end

Claims

The upper member plate and the lower member plate are opened apart from each other in the vicinity of branch base end portions at both ends extending in a bifurcated manner into a vehicle front portion on the front side in the vehicle front-rear direction and a vehicle rear portion on the rear side. Except for the part, it is integrally formed by joining at the periphery so as to form a closed cross section, and has a support point of the front arm of a pair of lower arms that support the wheels at the front part of the vehicle located outside the closed cross section, respectively. A suspension cross member having a support point of a rear arm inserted from the opening, located in the closed cross section at the vehicle rear portion, and attached to the lower surface of the vehicle body extending in the vehicle width direction,
Between the upper member plate and the lower member plate, it is provided on the inner side in the vehicle width direction with respect to the support point of the rear arm, and the peripheral edge is from the separation start point on the front arm side of the opening. A bulkhead that extends toward the rear side in the vehicle longitudinal direction along the inner surface of the lower member plate and the inner surface of the lower member plate, and is joined to the upper member plate and the lower member plate,
The suspension cross member, wherein the bulkhead is joined to the upper member plate and the lower member plate at least in the vicinity of a separation start point on the front arm side.

2. The suspension cross member according to claim 1, wherein an opening size of the opening gradually increases from a departure start point on the front arm side. 3.

A peripheral flange is erected on the periphery of the bulkhead from the portion corresponding to the separation start point on the front arm side toward the opening side over a predetermined range, and the peripheral flange and the upper member plate, respectively. The suspension cross member according to claim 1, wherein the suspension cross member is joined to the lower member plate.

Furthermore, between the upper member plate and the lower member plate, one end is joined to the bulkhead in the vicinity of the separation start point on the front arm side, and the other end is connected to the inner surface of the upper member plate and the lower member. The suspension cross member according to any one of claims 1 to 3, further comprising a support member that extends along the inner surface of the plate toward the front in the vehicle front-rear direction and is joined to the upper member plate and the lower member plate. .