JP2004268637A

JP2004268637A - Car body front part structure

Info

Publication number: JP2004268637A
Application number: JP2003059023A
Authority: JP
Inventors: Tadashi Makita; 匡史牧田; Pal Chinmoi; パルチンモイ
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 2003-03-05
Filing date: 2003-03-05
Publication date: 2004-09-30
Anticipated expiration: 2023-03-05
Also published as: JP4123014B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a car body front part structure capable of avoiding load concentration in the axial direction of an axial direction skeleton member by decentralization of a load at the time of frontal collision and capable of favorably carrying out load transmission in the axial direction of a longitudinal direction skeleton member even at the time of collision small in a lapping rate. <P>SOLUTION: It is possible to avoid concentration of the load in the axial direction of the longitudinal direction skeleton member 2 as bending deformation gradually proceeds so that an opposed wall surface of a curved part 2A makes contact with a back surface 4a against the back surface 4a in accordance with retreating of a car widthwise direction skeleton member 4 at the time of frontal collision of a vehicle and a collision contact area increases at a part on the opposite side of a center of curvature P of the curved part 2A since a wedge type open space S exists between the back surface 4a of the car widthwise direction skeleton member 4 and the wall surface facing the back surface 4a of the curved part 2A of the longitudinal direction skeleton member 2. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は自動車の車体前部構造に関する。
【０００２】
【従来の技術】
自動車の車体前部構造の中には、前後方向骨格部材であるフロントサイドメンバの前端と、車幅方向骨格部材であるファーストクロスメンバとを、フロントサイドメンバの軸線上に配置したクラッシュボックスを介して結合して、車両の前面衝突の際には該クラッシュボックスが潰れ変形することによって初期エネルギーを吸収すると共に、フロントサイドメンバの軸方向の座屈変形（軸圧潰）を安定化させるようにしたものがある（例えば、特許文献１参照）。
【０００３】
【特許文献１】
特開２００２−３５６１７９号公報（第３頁、図４）
【０００４】
【発明が解決しようとする課題】
車両の前面衝突時におけるキャビンの変形を小さく抑制させるためには、前述のように前後方向骨格部材の軸圧潰によるエネルギー吸収が有効であるが、前面衝突時に前後方向骨格部材の軸方向に荷重が集中する傾向となる。
【０００５】
一方、車両の前面衝突時には、自車両および相手車両の損壊度合いを共に小さく抑制できることが望まれるが、例えば大型車両と小型車両のように前端部形状が不一致の車両の前面衝突等では、前述のように前後方向骨格部材に軸方向荷重が集中することも相俟ってインタラクション不足になる可能性がある。
【０００６】
そこで、本発明は車両の前面衝突時には荷重を分散できて前後方向骨格部材の軸方向に荷重が集中するのを回避できると共に、ラップ率が小さな衝突時でも前後方向骨格部材への軸方向荷重伝達を良好に行わせることができる車体前部構造を提供するものである。
【０００７】
【課題を解決するための手段】
本発明の車体前部構造にあっては、車幅方向両側部に車体前後方向に延在配置した一対の前後方向骨格部材と、この一対の前後方向骨格部材の前端に跨って結合されて車幅方向に延在する車幅方向骨格部材とは、この車幅方向骨格部材の背面に対して前記前後方向骨格部材の前端を結合してあり、
一方、この前後方向骨格部材は、その前端部分に車幅方向骨格部材との結合部分よりも車体後方位置に設定した曲率変化点から前方部分を弯曲させた弯曲部を備えていて、
前記車幅方向骨格部材の背面と、該背面に対向する弯曲部の壁面との間にくさび状の開放空間を形成したこと、を特徴としている。
【０００８】
【発明の効果】
本発明によれば、車幅方向骨格部材の背面と、前後方向骨格部材の弯曲部の前記背面と対向する壁面との間にくさび状の開放空間が存在しているため、車両の前面衝突時に車幅方向骨格部材の後退に伴ってその背面に対して前記弯曲部の対向壁面が該背面に接するように倒れながら徐々に曲げ変形が進行し、弯曲部の曲率中心と反対側の部分で衝突接触面積が増加して、この接触面積の増加方向に荷重が分散されて前後方向骨格部材の軸方向に荷重が集中するのを回避することができる。
【０００９】
【発明の実施の形態】
以下、本発明の実施形態を図面と共に詳述する。
【００１０】
図１は本発明の第１実施形態を適用した自動車の車体骨格構造を示す斜視図、図２は本発明の第１実施形態を示す斜視図、図３は図２におけるフロントサイドメンバとセンタークロスメンバとを示す斜視図、図４は図３の要部を示す平面図、図５はフロントサイドメンバとセンタークロスメンバとの結合部分を示す分解斜視図、図６は図５のＡ−Ａ線に沿う断面図、図７はフロントサイドメンバとセンタークロスメンバとの結合部分の異なる例を示す分解斜視図、図８はフロントサイドメンバの一般部と弯曲部との結合部分を示す分解斜視図、図９は図８のＢ−Ｂ線に沿う断面図、図１０はフロントサイドメンバの一般部と弯曲部との結合部分の異なる例を示す分解斜視図、図１１は本発明の第１実施形態の作用を示す説明図、図１２は本発明に対する比較例の作用を示す説明図である。
【００１１】
本実施形態の車体前部構造は図１に示すように、フロントコンパートメントＦ・Ｃの左右側壁を構成するフードリッジパネル１の下端部に、車体前後方向に延在する前後方向骨格部材としてのフロントサイドメンバ２を接合配置してある。
【００１２】
このフロントサイドメンバ２は車両の前面衝突時における主要なエネルギー吸収部材となるもので閉断面に形成され、その後端部はダッシュパネル１３からフロアパネル６の下側に廻り込んでエクステンションサイドメンバとして後方へ延設してある。
【００１３】
フードリッジパネル１の上端部には、同じく車体前後方向に延在する前後方向骨格部材としての閉断面構造のフードリッジメンバ３を接合配置してある。
【００１４】
左右一対のフロントサイドメンバ２の前端部間、および左右一対のフードリッジメンバ３の前端部間に跨って、閉断面構造の車幅方向骨格部材としてのセンタークロスメンバ４、アッパークロスメンバ５を結合配置してある。
【００１５】
キャビン骨格は、フロアパネル６の左右両側部に配設したサイドシル７、ルーフパネル８の左右両側部に配設したルーフサイドレール９、これらサイドシル７とルーフサイドレール９とに跨って上下方向に配設したフロントピラー１０、センターピラー１１、リヤピラー１２の各種ピラー、およびダッシュパネル１３の上端部で左右のフロントピラー１０に跨って配設したカウルボックス１４等により構成してある。
【００１６】
前記フロントサイドメンバ２は、エクステンションサイドメンバとの連設部分でアウトリガー１４を介してサイドシル７の前端部に結合してある。
【００１７】
また、フードリッジメンバ３は本実施形態ではその後端部をフードリッジパネル１の骨格部であるストラットタワー１ａに結合して、該ストラットタワー１ａを介してカウルボックス１４およびフロントピラー１０に連設してある。
【００１８】
また、フロントコンパートメントＦ・Ｃの底部には、パワーユニット等を搭載支持するためのサブフレーム１６を配設してある。
【００１９】
サブフレーム１６は前後方向骨格部材としての左右のサイドフレーム１７と、左右のサイドフレーム１７の前端部間に跨って結合した車幅方向骨格部材としてのロアクロスメンバ１８とを備え、本実施形態では左右のサイドフレーム１７の後端部をリヤフレーム１９で連設して平面井桁状に形成してある。
【００２０】
このサブフレーム１６は前記各フレーム１７，１９およびロアクロスメンバ１８の何れも閉断面構造としてあり、サイドフレーム１７の前後方向中間部をフロントサイドメンバ２の下面にマウント部材を介して結合すると共に、該サイドフレーム１７の後端部をアウトリガー１４の下面にマウント部材を介して結合してある。
【００２１】
前記車幅方向骨格部材としてのセンタークロスメンバ４，アッパークロスメンバ５，およびロアクロスメンバ１８は、図２に示すように前端位置を上下方向に揃えて配設してあり、両側部分で上下方向のステイメンバ２０により結合して連設してある。
【００２２】
前述の前後方向骨格部材２，３，１７は、それらの前端を前記車幅方向骨格部材４，５，１８の背面に結合してある。
【００２３】
そして、これらの前後方向骨格部材２，３，１７は、それらの前端部分に車幅方向骨格部材４，５，１８との結合部分よりも車体後方位置に設定した曲率変化点Ｋから前方部分を、Ｐを曲率中心として所要の曲率で弯曲させた弯曲部２Ａ，３Ａ，１７Ａを備えていて、車幅方向骨格部材４，５，１８の背面４ａ，５ａ，１８ａと、これに対向する弯曲部２Ａ，３Ａ，１７Ａの壁面との間にくさび状の開放空間Ｓを形成してある。
【００２４】
本実施形態では前記弯曲部２Ａ，３Ａ，１７Ａを、何れも曲率変化点Ｋから車幅方向内側に向けて弯曲して形成してある。
【００２５】
図３〜図１０に何れも前後方向骨格部材、および車幅方向骨格部材として、フロントサイドメンバ２とセンタークロスメンバ４の構造を代表して示しているが、フードリッジメンバ３とアッパークロスメンバ５、およびサイドフレーム１７とロアクロスメンバ１８も同様の構造が採用される。
【００２６】
図５，図６に示す例では、センタークロスメンバ４の背面に平面Ｔ字状のブラケット２１をボルト２２固定し、該ブラケット２１の受片２１Ａの側面に突設したプラグ部２１Ｂに弯曲部２Ａの端末開口を嵌合すると共に、その周縁部を受片２１Ａに溶接して、センタークロスメンバ４とフロントサイドメンバ２とを結合している。
【００２７】
また、図７に示す例では、センタークロスメンバ４の背面に複数のスタッドボルト２３を配設し、弯曲部２Ａの対向面に設けたボルト挿通孔２４をこのスタッドボルト２３に挿通してナット２５で締結することにより、センタークロスメンバ４とフロントサイドメンバ２とを結合している。
【００２８】
フロントサイドメンバ２の弯曲部２Ａは一般部２Ｂと一体成形してもよいが、図８〜図１０の例では弯曲部２Ａを例えば曲率変化点Ｋ部分を境として一般部２Ｂと別体に形成して、該一般部２Ｂの前端部に結合するようにしている。
【００２９】
図８，図９に示す例では、一般部２Ｂの前端部に板厚相当の段差をもって小径部２Ｂ′を形成し、該小径部２Ｂ′を弯曲部２Ａの後端末開口に嵌合すると共に、その差込み周縁部を溶接してこれら弯曲部２Ａと一般部２Ｂとを結合している。
【００３０】
図１０に示す例では、弯曲部２Ａの後端末に複数のスタッドボルト２７を突設した端蓋２６を固設する一方、一般部２Ｂの前端末に複数のボルト挿通孔２８ａを設けた端蓋２８を固設し、これらボルト挿通孔２８ａをスタッドボルト２７に挿通して端蓋２６，２８同士を突合わせて、ナット２９で締結することによってこれら弯曲部２Ａと一般部２Ｂとを結合している。
【００３１】
一方、車幅方向骨格部材である前記センタークロスメンバ４，アッパークロスメンバ５，ロアクロスメンバ１８は、少なくとも前後方向骨格部材であるフロントサイドメンバ２，フードリッジメンバ３，サイドフレーム１７の各弯曲部２Ａ，３Ａ，１７Ａの前端を結合する両側端部を、平面視して車体後方に向けて弯曲して形成してある。
【００３２】
以上の実施形態の構造によれば、例えば前記車幅方向骨格部材であるセンタークロスメンバ４と、前後方向骨格部材であるフロントサイドメンバ２との関係にあっては、該センタークロスメンバ４の背面４ａとフロントサイドメンバ２の弯曲部２Ａの前記背面４ａと対向する壁面との間にくさび状の開放空間Ｓが存在しているため、車両の前面衝突時に図１１の（Ａ）に示す状態から（Ｂ）に示すように、センタークロスメンバ４の後退に伴ってその背面４ａに対して前記弯曲部２Ａの対向壁面が該背面４ａに接するように倒れながら徐々に曲げ変形が進行し、弯曲部２Ａの曲率中心Ｐと反対側の部分で衝突接触面積ＳＡが図１１のＬａからＬｂへと拡大して、この接触面積ＳＡの増加方向に荷重が分散されてフロントサイドメンバ２の軸方向に荷重が集中するのを回避することができる。
【００３３】
図１２は本発明の対比例の作用を示しており、この対比例はフロントサイドメンバ２′をその先端に至るまで直状に形成して、この先端をセンタークロスメンバ４′の背面４ａ′に結合して構成したもので、この対比例の構造では車両の前面衝突時にセンタークロスメンバ４′が後退すると、フロントサイドメンバ２′は図１２の（Ａ）に示す状態から（Ｂ）に示すように、その先端部分が軸方向に蛇腹状に座屈変形するようになり、該フロントサイドメンバ２′の前端の衝突接触面積ＳＡ′は同図の（Ｃ）に示すように変形前と殆ど変わらず、フロントサイドメンバ２の軸方向に荷重が集中する傾向となる。
【００３４】
本実施形態にあっては、前述のような前後方向骨格部材の前端部における衝突接触面積の拡大作用は、フードリッジメンバ３およびサブフレーム１６のサイドフレーム１７においても全く同様に行われる。
【００３５】
この結果、衝突物Ｍの衝突初期では前記弯曲部２Ａ，３Ａ，１７Ａが曲げ変形し、該弯曲部２Ａ，３Ａ，１７Ａがそれらの曲率変化点Ｋまで曲げ変形すると、続いて一般部２Ｂ，３Ｂ，１７Ｂが軸方向に蛇腹状に座屈変形を開始し、これら曲げ変形と軸圧潰変形とによって効率よく衝突エネルギーを吸収する。
【００３６】
しかも、前述のように前後方向骨格部材２，３，１７への軸方向の荷重集中を回避するため、車体前部の損壊度合いを小さく抑制することができ、衝突物Ｍが車両であった場合には、相対的にこの相手車両の損壊度合いも小さく抑制することができる。
【００３７】
また、前述のように前記弯曲部２Ａ，３Ａ，１７Ａがくさび状の開放空間Ｓの部分で曲げ変形して、該開放空間Ｓ側で衝突接触面積を拡大できるため、自車両と相手車両の前後方向の骨格部材同士のラップ率が小さな衝突であっても、この衝突面積の拡大により前後方向骨格部材２，３，１７に軸方向荷重を確実に伝達させて、効率的な衝突エネルギー吸収機能を発揮させることができる。
【００３８】
特に、本実施形態では前記弯曲部２Ａ，３Ａ，１７Ａを、曲率変化点Ｋから車幅方向内側に向けて弯曲して形成してあるため、自車両の前後方向骨格部材２，３，１７に対して相手車両の前後方向骨格部材が車幅方向外側にずれていても、前記弯曲部２Ａ，３Ａ，１７Ａの曲げ変形によって衝突接触面積が時間とともに車幅方向外側に向けて拡大することにより、前後方向骨格部材相互に軸方向荷重を安定して作用させることができる。
【００３９】
とりわけ、本実施形態では車幅方向骨格部材４，５，１８の両側端部を平面視して車体後方に向けて弯曲して形成してあるため、前記車幅方向外側に向けての衝突接触面積の拡大をより良好に行わせることができる。
【００４０】
また、このような衝突性能上の効果とは別に、弯曲部２Ａ，３Ａ，１７Ａをほぼ曲率変化点Ｋを境として一般部２Ｂ，３Ｂ，１７Ｂと別体に形成してあるので、これら弯曲部２Ａ，３Ａ，１７Ａを要求特性に応じた曲率で容易に形成することができる。
【００４１】
図１３は本発明の第２実施形態を示すもので、本図では前後方向骨格部材および車幅方向骨格部材として、フロントサイドメンバ２とセンタークロスメンバ４とを代表して示しているが、フードリッジメンバ３，サイドフレーム１７に関しても同様の構造が採られる。
【００４２】
この第２実施形態ではフロントサイドメンバ２の弯曲部２Ａを、曲率変化点Ｋから車幅方向外側に向けて弯曲して形成してあって、その他の構成については前記第１実施形態と同様である。
【００４３】
従って、この第２実施形態の構造によれば、前記第１実施形態と同様の作用効果が得られるが、本実施形態ではくさび状の開放空間Ｓが車幅方向内側に形成されて、弯曲部２Ａの曲げ変形による衝突接触面積の拡大化が車幅中央に向けて行われるため、前面衝突時に自車両のフロントサイドメンバ２に対して相手車両のフロントサイドメンバが車幅中央側にずれていても、前記弯曲部２Ａの曲げ変形による車幅中央側への衝突接触面積の拡大により、フロントサイドメンバ相互に軸方向荷重を安定して作用させることができる。
【００４４】
図１４は本発明の第３実施形態を示すもので、本図では前後方向骨格部材および車幅方向骨格部材として、フロントサイドメンバ２とセンタークロスメンバ４とを代表して示しているが、フードリッジメンバ３，サイドフレーム１７に関しても同様の構造が採られる。
【００４５】
この第３実施形態ではフロントサイドメンバ２の弯曲部２Ａを、曲率変化点Ｋから上方向に向けて弯曲して形成してあって、その他の構成については前記第１実施形態と同様である。
【００４６】
従って、この第３実施形態の構造によれば、前記第１実施形態と同様の作用効果が得られるが、本実施形態ではくさび状の開放空間Ｓが下側に形成されて、弯曲部２Ａの曲げ変形による衝突接触面積の拡大化が下側に向けて行われるため、前面衝突時に自車両のフロントサイドメンバ２に対して相手車両のフロントサイドメンバが下側にずれていても、前記弯曲部２Ａの曲げ変形による下側への衝突接触面積の拡大により、フロントサイドメンバ相互に軸方向荷重を安定して作用させることができる。
【００４７】
図１５は本発明の第４実施形態を示すもので、本図では前後方向骨格部材および車幅方向骨格部材として、フロントサイドメンバ２とセンタークロスメンバ４とを代表して示しているが、フードリッジメンバ３，サイドフレーム１７に関しても同様の構造が採られる。
【００４８】
この第４実施形態ではフロントサイドメンバ２の弯曲部２Ａを、曲率変化点Ｋから下方向に向けて弯曲して形成してあって、その他の構成については前記第１実施形態と同様である。
【００４９】
従って、この第４実施形態の構造によれば、前記第１実施形態と同様の作用効果が得られるが、本実施形態ではくさび状の開放空間Ｓが上側に形成されて、弯曲部２Ａの曲げ変形による衝突接触面積の拡大化が上側に向けて行われるため、前面衝突時に自車両のフロントサイドメンバ２に対して相手車両のフロントサイドメンバが上側にずれていても、前記弯曲部２Ａの曲げ変形による上側への衝突接触面積の拡大により、フロントサイドメンバ相互に軸方向荷重を安定して作用させることができる。
【００５０】
ところで、本発明の車体前部構造を前記実施形態を例にとって説明したが、この実施形態に限ることなく本発明の要旨を逸脱しない範囲で他の実施形態を各種採ることができる。
【図面の簡単な説明】
【図１】本発明の第１実施形態を採用した自動車の車体骨格構造を示す斜視図。
【図２】本発明の第１実施形態を示す斜視図。
【図３】図２におけるフロントサイドメンバとセンタークロスメンバとを示す斜視図。
【図４】図３の要部を示す平面図。
【図５】フロントサイドメンバとセンタークロスメンバとの結合部分を示す分解斜視図。
【図６】図５のＡ−Ａ線に沿う断面図。
【図７】フロントサイドメンバとセンタークロスメンバとの結合部分の異なる例を示す分解斜視図。
【図８】フロントサイドメンバの一般部と弯曲部との結合部分を示す分解斜視図。
【図９】図８のＢ−Ｂ線に沿う断面図。
【図１０】フロントサイドメンバの一般部と弯曲部との結合部分の異なる例を示す分解斜視図。
【図１１】本発明の第１実施形態の作用を示す説明図。
【図１２】本発明に対する比較例の作用を示す説明図。
【図１３】本発明の第２実施形態におけるフロントサイドメンバとセンタークロスメンバとを示す斜視図。
【図１４】本発明の第３実施形態におけるフロントサイドメンバとセンタークロスメンバとを示す斜視図。
【図１５】本発明の第４実施形態におけるフロントサイドメンバとセンタークロスメンバとを示す斜視図。
【符号の説明】
１フードリッジパネル
２フロントサイドメンバ（前後方向骨格部材）
２Ａ弯曲部
２Ｂ一般部
３フードリッジメンバ（前後方向骨格部材）
３Ａ弯曲部
３Ｂ一般部
４センタークロスメンバ（車幅方向骨格部材）
４ａ背面
５アッパークロスメンバ（車幅方向骨格部材）
５ａ背面
１６サブフレーム
１７サイドフレーム（前後方向骨格部材）
１７Ａ弯曲部
１７Ｂ一般部
１８ロアクロスメンバ（車幅方向骨格部材）
１８ａ背面
Ｆ・Ｃフロントコンパートメント
Ｋ曲率変化点
Ｓくさび状の開放空間
Ｐ曲率中心[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle body front structure of an automobile.
[0002]
[Prior art]
In the vehicle body front structure, the front end of the front side member, which is a longitudinal frame member, and the first cross member, which is a vehicle width direction frame member, are disposed via a crash box arranged on the axis of the front side member. In the event of a frontal collision of the vehicle, the crush box is crushed and deformed to absorb initial energy and to stabilize buckling deformation (axial crushing) of the front side member in the axial direction. (For example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-2002-356179 (page 3, FIG. 4)
[0004]
[Problems to be solved by the invention]
In order to suppress the deformation of the cabin at the time of a frontal collision of the vehicle, energy absorption by axial crushing of the longitudinal frame member is effective as described above, but a load is applied in the axial direction of the longitudinal frame member at the time of a frontal collision. They tend to concentrate.
[0005]
On the other hand, at the time of a frontal collision of the vehicle, it is desired that both the own vehicle and the opponent vehicle be able to suppress the degree of damage to a small extent. Thus, the interaction may be insufficient due to the concentration of the axial load on the longitudinal frame member.
[0006]
Therefore, the present invention can disperse the load at the time of a frontal collision of the vehicle, avoid the load from being concentrated in the axial direction of the longitudinal frame member, and transmit the axial load to the longitudinal frame member even at the time of a collision with a small lap ratio. To provide a vehicle body front structure capable of favorably performing the following.
[0007]
[Means for Solving the Problems]
In the vehicle body front structure according to the present invention, a pair of front-rear skeletal members extending in the vehicle front-rear direction on both sides in the vehicle width direction, and the vehicle being joined across the front ends of the pair of front-rear skeletal members. The vehicle width direction skeletal member extending in the width direction has the front end of the front-rear direction skeletal member coupled to the rear surface of the vehicle width direction skeletal member,
On the other hand, the front-rear direction skeleton member has a curved portion at a front end portion of which a front portion is curved from a curvature change point set at a rearward position of the vehicle body with respect to a coupling portion with the vehicle width direction skeleton member,
A wedge-shaped open space is formed between a back surface of the vehicle width direction frame member and a wall surface of a curved portion facing the back surface.
[0008]
【The invention's effect】
According to the present invention, since there is a wedge-shaped open space between the back surface of the vehicle width direction skeleton member and the wall surface facing the back surface of the curved portion of the front-rear direction skeleton member, at the time of a frontal collision of the vehicle, With the retraction of the vehicle width direction skeletal member, bending deformation gradually progresses while the opposing wall surface of the curved portion falls down so as to be in contact with the rear surface, and a collision occurs at a portion opposite to the curvature center of the curved portion. It is possible to prevent the contact area from increasing and the load from being dispersed in the increasing direction of the contact area and the load from being concentrated in the axial direction of the front-back skeleton member.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0010]
FIG. 1 is a perspective view showing a vehicle body frame structure to which a first embodiment of the present invention is applied, FIG. 2 is a perspective view showing a first embodiment of the present invention, and FIG. 3 is a front side member and a center cross in FIG. FIG. 4 is a plan view showing a main part of FIG. 3, FIG. 5 is an exploded perspective view showing a connecting portion between a front side member and a center cross member, and FIG. 6 is a line AA of FIG. 7, FIG. 7 is an exploded perspective view showing a different example of a coupling portion between the front side member and the center cross member, FIG. 8 is an exploded perspective view showing a coupling portion between a general portion and a curved portion of the front side member, 9 is a cross-sectional view taken along the line BB of FIG. 8, FIG. 10 is an exploded perspective view showing a different example of a coupling portion between a general portion and a curved portion of the front side member, and FIG. 11 is a first embodiment of the present invention. FIG. 12 is an explanatory view showing the operation of Is an explanatory view showing an operation of a comparative example against.
[0011]
As shown in FIG. 1, the vehicle body front structure according to the present embodiment includes a front skeleton member 1 extending in the vehicle front-rear direction at the lower end of a hood ridge panel 1 forming left and right side walls of the front compartments FC. The side members 2 are joined and arranged.
[0012]
The front side member 2 serves as a main energy absorbing member at the time of a frontal collision of the vehicle and is formed in a closed cross section. The rear end of the front side member 2 extends from the dash panel 13 to the lower side of the floor panel 6 to serve as an extension side member. It has been extended to.
[0013]
At the upper end of the hood ridge panel 1, a hood ridge member 3 having a closed cross-sectional structure as a longitudinal frame member also extending in the longitudinal direction of the vehicle body is joined and arranged.
[0014]
The center cross member 4 and the upper cross member 5 as a vehicle width direction skeleton member having a closed cross-section structure are joined between the front end portions of the pair of left and right front side members 2 and between the front end portions of the pair of left and right hood ridge members 3. It is arranged.
[0015]
The cabin skeleton includes side sills 7 disposed on both left and right sides of the floor panel 6, roof side rails 9 disposed on both left and right sides of the roof panel 8, and is disposed vertically across the side sill 7 and the roof side rail 9. The front pillar 10, the center pillar 11, and the rear pillar 12 are provided, and the cowl box 14 is disposed at the upper end of the dash panel 13 so as to straddle the left and right front pillars 10.
[0016]
The front side member 2 is connected to the front end of the side sill 7 via an outrigger 14 at a portion connected to the extension side member.
[0017]
In the present embodiment, the rear end of the hood ridge member 3 is connected to a strut tower 1a which is a frame of the hood ridge panel 1, and is connected to the cowl box 14 and the front pillar 10 via the strut tower 1a. It is.
[0018]
Further, a sub-frame 16 for mounting and supporting a power unit and the like is provided at the bottom of the front compartments FC.
[0019]
The sub-frame 16 includes left and right side frames 17 as front and rear direction frame members, and a lower cross member 18 as a vehicle width direction frame member joined across front ends of the left and right side frames 17. The rear ends of the left and right side frames 17 are connected to each other by a rear frame 19 and are formed in a plane cross-girder shape.
[0020]
Each of the sub-frames 16 has a closed cross-sectional structure of each of the frames 17, 19 and the lower cross member 18, and connects the intermediate portion of the side frame 17 in the front-rear direction to the lower surface of the front side member 2 via a mounting member. The rear end of the side frame 17 is connected to the lower surface of the outrigger 14 via a mount member.
[0021]
The center cross member 4, the upper cross member 5, and the lower cross member 18 as the frame members in the vehicle width direction are disposed with their front end positions aligned vertically as shown in FIG. Are connected to each other by the stay member 20 of FIG.
[0022]
The front and rear frame members 2, 3, and 17 have their front ends connected to the rear surfaces of the vehicle width direction frame members 4, 5, and 18, respectively.
[0023]
The front and rear skeletal members 2, 3, and 17 have a front portion extending from a curvature change point K set at a rearward position of the vehicle body with respect to a connection portion with the vehicle width direction skeletal members 4, 5, and 18 at a front end thereof. , P with curved portions 2A, 3A, 17A curved at a required curvature with respect to the center of curvature, and the back surfaces 4a, 5a, 18a of the vehicle width direction skeletal members 4, 5, 18 and the curved portions opposed thereto. A wedge-shaped open space S is formed between the walls 2A, 3A and 17A.
[0024]
In the present embodiment, each of the curved portions 2A, 3A, 17A is formed by curving inward from the curvature change point K in the vehicle width direction.
[0025]
3 to 10 show the front side member 2 and the center cross member 4 as the front-rear direction frame member and the vehicle width direction frame member, respectively, but the hood ridge member 3 and the upper cross member 5 are shown. , And the side frame 17 and the lower cross member 18 have the same structure.
[0026]
In the example shown in FIGS. 5 and 6, a flat T-shaped bracket 21 is fixed to the back of the center cross member 4 by bolts 22, and a curved portion 2A is formed on a plug portion 21B protruding from a side surface of a receiving piece 21A of the bracket 21. The center cross member 4 and the front side member 2 are joined together by fitting the terminal opening of the center cross member 4 to the receiving piece 21A.
[0027]
In the example shown in FIG. 7, a plurality of stud bolts 23 are provided on the back surface of the center cross member 4, and a bolt insertion hole 24 provided on the opposite surface of the curved portion 2 </ b> A is inserted through the stud bolt 23 so that a nut 25 is inserted. Thus, the center cross member 4 and the front side member 2 are connected.
[0028]
The curved portion 2A of the front side member 2 may be formed integrally with the general portion 2B. However, in the examples of FIGS. 8 to 10, the curved portion 2A is formed separately from the general portion 2B at, for example, a curvature change point K. Thus, it is connected to the front end of the general portion 2B.
[0029]
8 and 9, a small-diameter portion 2B 'is formed at the front end of the general portion 2B with a step corresponding to the plate thickness, and the small-diameter portion 2B' is fitted into the rear terminal opening of the curved portion 2A. The bent portion 2A and the general portion 2B are joined by welding the insertion peripheral portion.
[0030]
In the example shown in FIG. 10, an end cover 26 having a plurality of stud bolts 27 protrudingly provided at a rear end of the curved portion 2A is fixed, while an end cover having a plurality of bolt insertion holes 28a provided at a front end of the general portion 2B. 28, and these bolt insertion holes 28a are inserted into the stud bolts 27, the end covers 26, 28 are butted together, and fastened with nuts 29 to connect the curved portion 2A and the general portion 2B. I have.
[0031]
On the other hand, the center cross member 4, the upper cross member 5, and the lower cross member 18, which are frame members in the vehicle width direction, are at least curved portions of the front side member 2, the hood ridge member 3, and the side frame 17 which are frame members in the front-rear direction. Both ends connecting the front ends of 2A, 3A and 17A are formed to be curved toward the rear of the vehicle body in plan view.
[0032]
According to the structure of the above-described embodiment, for example, the relationship between the center cross member 4 that is the vehicle width direction frame member and the front side member 2 that is the front-rear direction frame member is determined by the rear surface of the center cross member 4. Since a wedge-shaped open space S exists between the front side member 4a and the wall surface of the curved portion 2A of the front side member 2 facing the rear surface 4a, the state shown in FIG. As shown in FIG. 2B, as the center cross member 4 retreats, the wall surface facing the curved portion 2A falls down on the rear surface 4a so as to contact the rear surface 4a, and the bending deformation gradually progresses. The collision contact area SA expands from La to Lb in FIG. 11 at the portion opposite to the center of curvature P of 2A, and the load is dispersed in the increasing direction of the contact area SA so that the axial direction of the front side member 2 is increased. It is possible to load to avoid to focus on.
[0033]
FIG. 12 shows a comparative operation of the present invention. In this comparative example, the front side member 2 'is formed straight up to its tip, and this tip is attached to the back surface 4a' of the center cross member 4 '. In this comparative structure, when the center cross member 4 'retreats at the time of a frontal collision of the vehicle, the front side member 2' moves from the state shown in FIG. 12A to the state shown in FIG. In addition, the tip portion of the front side member 2 'buckles and deforms in the axial direction, and the collision contact area SA' of the front end of the front side member 2 'is almost the same as before deformation as shown in FIG. Instead, the load tends to concentrate in the axial direction of the front side member 2.
[0034]
In the present embodiment, the above-described action of enlarging the collision contact area at the front end portion of the front-rear skeletal member is performed in the same manner in the hood ridge member 3 and the side frame 17 of the sub-frame 16.
[0035]
As a result, in the early stage of the collision of the collision object M, the curved portions 2A, 3A, 17A are bent and deformed, and the bent portions 2A, 3A, 17A are bent and deformed to their curvature change points K, and subsequently the general portions 2B, 3B. , 17B start buckling deformation in the bellows shape in the axial direction, and efficiently absorb the collision energy by these bending deformation and axial crushing deformation.
[0036]
Moreover, as described above, the axial load concentration on the longitudinal frame members 2, 3, and 17 is avoided, so that the degree of damage to the front portion of the vehicle body can be suppressed to a small degree. Therefore, the degree of damage to the opponent vehicle can be relatively suppressed.
[0037]
Further, as described above, the curved portions 2A, 3A, and 17A are bent and deformed in the wedge-shaped open space S, so that the collision contact area can be increased on the open space S side. Even if the collision rate of the skeletal members in the directions is small, even if the collision rate is small, the expansion of the collision area ensures that the axial load is transmitted to the front-rear skeletal members 2, 3, and 17, thereby providing an efficient collision energy absorbing function. Can be demonstrated.
[0038]
In particular, in the present embodiment, since the curved portions 2A, 3A, 17A are formed by curving inward in the vehicle width direction from the curvature changing point K, the front and rear skeletal members 2, 3, 17 of the own vehicle are formed. On the other hand, even if the longitudinal frame member of the opponent vehicle is displaced outward in the vehicle width direction, the collision contact area is expanded outward in the vehicle width direction with time due to the bending deformation of the curved portions 2A, 3A, 17A. An axial load can be stably applied to the longitudinal frame members.
[0039]
In particular, in the present embodiment, since both end portions of the frame members 4, 5, and 18 in the vehicle width direction are formed to be curved toward the rear of the vehicle body in plan view, the collision contact toward the outside in the vehicle width direction is performed. The area can be expanded more favorably.
[0040]
In addition to such effects on the collision performance, the curved portions 2A, 3A, 17A are formed separately from the general portions 2B, 3B, 17B with the curvature change point K as a boundary. 2A, 3A and 17A can be easily formed with a curvature according to required characteristics.
[0041]
FIG. 13 shows a second embodiment of the present invention. In this figure, the front side member 2 and the center cross member 4 are representatively shown as a front-back direction frame member and a vehicle width direction frame member. The same structure is adopted for the ridge member 3 and the side frame 17.
[0042]
In the second embodiment, the curved portion 2A of the front side member 2 is formed by curving outward from the curvature change point K in the vehicle width direction, and other configurations are the same as those of the first embodiment. is there.
[0043]
Therefore, according to the structure of the second embodiment, the same operation and effect as those of the first embodiment can be obtained. However, in this embodiment, the wedge-shaped open space S is formed inside the vehicle width direction, and the curved portion is formed. Since the collision contact area is increased toward the center of the vehicle width due to the bending deformation of 2A, the front side member of the opponent vehicle is shifted toward the center of the vehicle width with respect to the front side member 2 of the own vehicle at the time of a frontal collision. In addition, an increase in the collision contact area on the vehicle width center side due to the bending deformation of the curved portion 2A allows the front side members to stably apply an axial load to each other.
[0044]
FIG. 14 shows a third embodiment of the present invention. In this figure, a front side member 2 and a center cross member 4 are shown as a front-back direction frame member and a vehicle width direction frame member. The same structure is adopted for the ridge member 3 and the side frame 17.
[0045]
In the third embodiment, the curved portion 2A of the front side member 2 is formed by curving upward from the curvature change point K, and other configurations are the same as those of the first embodiment.
[0046]
Therefore, according to the structure of the third embodiment, the same function and effect as those of the first embodiment can be obtained. However, in the present embodiment, the wedge-shaped open space S is formed on the lower side, and the curved portion 2A is formed. Since the collision contact area is increased downward due to bending deformation, even if the front side member of the opponent vehicle is displaced downward with respect to the front side member 2 of the host vehicle at the time of a frontal collision, the curved portion is not bent. The axial load can be stably applied to the front side members by enlarging the collision contact area to the lower side due to the bending deformation of 2A.
[0047]
FIG. 15 shows a fourth embodiment of the present invention. In this figure, the front side member 2 and the center cross member 4 are representatively shown as a longitudinal frame member and a vehicle width direction frame member. The same structure is adopted for the ridge member 3 and the side frame 17.
[0048]
In the fourth embodiment, the curved portion 2A of the front side member 2 is formed by curving downward from the curvature changing point K, and the other configuration is the same as that of the first embodiment.
[0049]
Therefore, according to the structure of the fourth embodiment, the same operation and effect as those of the first embodiment can be obtained. However, in the present embodiment, the wedge-shaped open space S is formed on the upper side, and the bending of the curved portion 2A is performed. Since the collision contact area is increased upward due to the deformation, even if the front side member of the opponent vehicle is displaced upward with respect to the front side member 2 of the own vehicle at the time of a frontal collision, the bending of the curved portion 2A is performed. The axial load can be stably applied to the front side members due to the increase in the area of the collision contact upward due to the deformation.
[0050]
Incidentally, the vehicle body front structure of the present invention has been described by taking the above embodiment as an example. However, the present invention is not limited to this embodiment, and various other embodiments can be adopted without departing from the gist of the present invention.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a vehicle body skeleton structure of an automobile employing a first embodiment of the present invention.
FIG. 2 is a perspective view showing the first embodiment of the present invention.
FIG. 3 is a perspective view showing a front side member and a center cross member in FIG. 2;
FIG. 4 is a plan view showing a main part of FIG. 3;
FIG. 5 is an exploded perspective view showing a coupling portion between a front side member and a center cross member.
FIG. 6 is a sectional view taken along line AA of FIG. 5;
FIG. 7 is an exploded perspective view showing a different example of a coupling portion between a front side member and a center cross member.
FIG. 8 is an exploded perspective view showing a joint portion between a general portion and a curved portion of the front side member.
FIG. 9 is a sectional view taken along the line BB of FIG. 8;
FIG. 10 is an exploded perspective view showing a different example of a coupling portion between a general portion and a curved portion of the front side member.
FIG. 11 is an explanatory view showing the operation of the first embodiment of the present invention.
FIG. 12 is an explanatory view showing the operation of a comparative example with respect to the present invention.
FIG. 13 is a perspective view showing a front side member and a center cross member according to a second embodiment of the present invention.
FIG. 14 is a perspective view showing a front side member and a center cross member according to a third embodiment of the present invention.
FIG. 15 is a perspective view showing a front side member and a center cross member according to a fourth embodiment of the present invention.
[Explanation of symbols]
1 Food ridge panel 2 Front side member (back and forth direction frame member)
2A Curved portion 2B General portion 3 Food ridge member (front-back skeletal member)
3A Curved part 3B General part 4 Center cross member (Vehicle width direction frame member)
4a Back surface 5 Upper cross member (frame member in the vehicle width direction)
5a Back 16 Sub frame 17 Side frame (Frame member in the front-rear direction)
17A Curved portion 17B General portion 18 Lower cross member (vehicle width direction frame member)
18a Back FC Front compartment K Curvature change point S Wedge-shaped open space P Center of curvature

Claims

A pair of longitudinal frame members extending in the vehicle longitudinal direction on both sides in the vehicle width direction of the front compartment,
A vehicle width direction skeletal member that is connected across the front ends of the pair of front-rear direction skeletal members and extends in the vehicle width direction,
The front end of the front-rear direction frame member is coupled to the rear surface of the vehicle width direction frame member,
The front-rear direction frame member includes a curved portion formed by bending a front portion at a front end portion from a curvature change point set at a rearward position of the vehicle body with respect to a coupling portion with the vehicle width direction frame member,
A vehicle body front structure, wherein a wedge-shaped open space is formed between a rear surface of the vehicle width direction frame member and a wall surface of a curved portion facing the rear surface.

2. The vehicle body front structure according to claim 1, wherein the curved portion is formed separately from the general portion of the front-rear skeletal member and is connected to the front end of the general portion of the front-rear skeletal member.

3. The vehicle body front structure according to claim 1, wherein the curved portion is formed by curving outward from the curvature changing point in the vehicle width direction.

The vehicle body front structure according to claim 1, wherein the curved portion is formed by curving inward in the vehicle width direction from a curvature change point.

The vehicle body front structure according to claim 1, wherein the curved portion is formed by curving upward from a curvature change point.

3. The vehicle body front structure according to claim 1, wherein the curved portion is formed by curving downward from a curvature changing point.

5. The vehicle body front structure according to claim 3, wherein the vehicle width direction frame member is formed by bending at least both end portions connecting the front-rear direction frame member toward the rear of the vehicle body in plan view. .