JP2004160485A

JP2004160485A - Method of hydraulic forming for preliminary formed product and hollow formed product

Info

Publication number: JP2004160485A
Application number: JP2002328454A
Authority: JP
Inventors: Nariyuki Nakagawa; 成幸中川; Kenji Kanamori; 謙二金森
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 2002-11-12
Filing date: 2002-11-12
Publication date: 2004-06-10
Anticipated expiration: 2022-11-12
Also published as: JP4042538B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow formed product, which has a high degree of freedom for design and is easy to cause complete crush in the case of axial compression. <P>SOLUTION: Between a first metal plate (6) and a second metal plate (7) laminated to each other, there are provided a preliminary reinforcing portion (22) on which preliminary reinforcing members joined to the respective inner surfaces of the first metal plate and the second metal plate are arranged, a liquid pouring portion (21) into which liquid is poured in hydraulic forming, and an intermediate portion (23) which is located between the longitudinal preliminary reinforcing portions of the first and second metal plates and the liquid pouring portion, and has no preliminary reinforcing members. A preliminary formed product (20) is formed by joining both side edge portions (10), which run parallel to the first metal plate and the second metal plate, with each other. The preliminary formed product is gripped between an upper die and a lower die, in which a cavity is formed. And then, the hollow formed product is formed by expanding the preliminary formed product by pouring liquid into the liquid pouring portion of the preliminary formed product. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、液圧成形における予備成形体および中空成形体の液圧成形方法に関する。
【０００２】
【従来の技術】
フロントサイドメンバやクラッシュボックスのように衝撃吸収部材として機能する自動車の車体構造部材は、一般的に、衝撃の吸収に適した中空外郭形状を有している。この車体構造部材は、ある程度の強度を持つ一方で、衝撃の吸収も効果的にできるようにするため、その内部を仕切るように補強板が配され、かつ、長手方向に渡り断面形状が漸増するように構成される。このような車体構造部材の製造は押し出し成形によって行われる。
【０００３】
下記の特許文献１には、車体構造部材を押し出し材から成形する技術が開示されている。特許文献１に開示されている車体構造部材は、自動車前部で前後方向に軸線が延びる左右のクラッシュボックスである。クラッシュボックスはアルミ押し出し材から成形される。
【０００４】
クラッシュボックスを製造するには、まずその矩形中空部内を十字状に仕切る補強板を矩形中空部に配し、矩形中空部の外面から外側に向かって突出するフランジを一体的に押し出し成形した後、そのフランジの前方側から後方側に向かってフランジ幅が漸増するように、そのフランジを切断する。
【０００５】
このような手順で押し出し成形することによって、主に内部を仕切るように配された補強板と矩形中空部とによって大きな軸圧縮荷重が得られるとともに、フランジ幅が漸増したフランジ部にて軸圧縮荷重を漸増させることができる。
【０００６】
【特許文献１】
特開２００２−１５５９８１号公報
【０００７】
【発明が解決しようとする課題】
しかしながら、従来の車体構造部材では、主に衝撃エネルギーを吸収する矩形中空部を一定断面積とし、フランジ部のフランジ幅のみを漸増させることによりエネルギー吸収性能をコントロールしているため、性能設計の自由度が極めて狭い。また、矩形中空部が一定断面積であるため、軸圧縮時に潰れ残りが生じ、その分有効な潰れストロークが短くなってエネルギー吸収性能が不足する場合もあるという問題がある。
【０００８】
また、アルミ押し出し材を用いた場合、断面を仕切る補強板を押出し成形によって形成するため、矩形中空部は長手方向では一定断面積となり、長手方向の任意の位置に、断面を仕切る補強板を自由に配置することが困難であり、エネルギー吸収性能を設計する上で、形状やレイアウトの自由度が低いという問題がある。
【０００９】
本発明は、以上のような従来の種々の問題を解決するために成されたものであり、設計の自由度が大きく、軸圧縮時に潰れ残りが生じ難い構造を有する予備成形体および中空成形体の液圧成形方法の提供を目的とする。
【００１０】
【課題を解決するための手段】
上記した課題を解決し、目的を達成するため、本発明にかかる液圧成形における予備成形体は、互いに重ね合わされた少なくとも２枚の金属板を有し、当該２枚の金属板の長手方向に沿う両側縁部が接合され、液圧成形により当該２枚の金属板がその長手方向に伸延する中空外郭体へと膨出変形される液圧成形における予備成形体であって、前記２枚の金属板の間には、前記２枚の金属板のそれぞれの内面に接合された予備補強体が予め介装され、当該予備補強体の断面方向の幅は前記金属板の長手方向に向けて漸次変化しており、前記予備補強体は、前記液圧成形により、前記中空外郭体の内部を長手方向に伸延しかつ当該内部をその断面積が漸次変化する複数の空間に仕切る補強体へと変形されることを特徴とする。
【００１１】
また、上記した課題を解決し、目的を達成するため、発明にかかる中空成形体の液圧成形方法は、互いに重ね合せた第１金属板と第２金属板との間に、前記第１金属板および前記第２金属板のそれぞれの内面に接合された予備補強体が配設される予備補強部と、液圧成形の際に液体が注入される液体注入部と、前記第１金属板および前記第２金属板の長手方向の前記予備補強部と前記液体注入部との間に位置し前記予備補強体が配設されていない中間部とを設け、前記第１金属板および前記第２金属板の長手方向に沿う両側縁部を互いに接合して予備成形体を形成し、当該予備成形体をキャビティが形成される上型と下型の間に挟持し、前記予備成形体の液体注入部に液体を注入し、中空成形体を膨出成形することを特徴とする。
【００１２】
【発明の効果】
本発明の液圧成形における予備成形体によれば、液圧成形することにより、互いに重ね合わせた２枚の金属板により中空外郭体を成形でき、同時に、この中空外郭体の断面をその長手方向に断面積が漸次変化するように仕切る補強体を成形することができ、しかもその製造が容易である。加えて、補強体へと変形する予備補強体は、変形前の金属板に予め接合しておくことができるので、その接合作業が容易であるとともに、補強材のレイアウトおよび形状の自由度が高くなる。
【００１３】
本発明の中空成形体の液圧成形方法によれば、液体注入部と予備補強部との間に予備補強体が配置されていない中間部を設けているため、液体注入部へ高圧の液体を注入すると、まず中間部から徐々に変形していき、これに追従するように予備補強部が変形していく。したがって、補強体により仕切られた複数の空間の形状がばらつくことなく適正に形成され、これら空間に作用する均等な液圧により金属板を適正に膨出変形させていくことができ、高強度で、かつエネルギー吸収性能に優れた中空成形体を容易に製造することができる。
【００１４】
【発明の実施の形態】
以下に添付図面を参照して、本発明にかかる液圧成形における予備成形体および中空成形体の液圧成形方法の好適な実施の形態を詳細に説明する。
【００１５】
図１は、自動車車体１の前部の骨格を示す斜視図である。自動車車体１の前部には前後方向に延びるフロントサイドメンバ２が左右に設けられている。左右のフロントサイドメンバ２の前端には、クラッシュボックス３が連結され、クラッシュボックス３を介してフロントバンパー４が連結されている。左右のフロントサイドメンバ２の上方には、やはり左右のフードレッジ５が設けられている。車体前方からの衝突に対しては、主にこれらの各部材でエネルギーが吸収される。
【００１６】
［実施の形態１］
まず、自動車の車体構造としてのフロントサイドメンバ２に本発明を適用した実施の形態１について説明する。図２は、フロントサイドメンバ２の斜視図であり、図３は図２のＰ方向からの矢視図である。
【００１７】
フロントサイドメンバ２は、第１金属板６と第２金属板７を組み合わせてなる中空外郭体を有している。中空外郭体は中空断面形状で、長手方向に延びるに従い断面積が漸増する略矩形形状の閉断面構造をなしている。第１金属板６と第２金属板７は、図３に示すように、それぞれ略Ｌ字状に折曲して、中空外郭体の２つの側壁をそれぞれ形成している。これらの金属板６、７は、両側縁部１０の２箇所で長手方向に沿って互いに接合されている。両側縁部１０は、中空外郭体の矩形部分から外側に突出するフランジ形状を呈しており、その方向は矩形部の対角線上に延びるように突出しており、その突出端近傍で両金属板６、７が互いに接合されている。
【００１８】
中空外郭体の内部には、第１補強板８と第２補強板９とが互いにＬ字状に折曲して、かつ長手方向に延びる折曲部１１で接合され、断面略十字形状の補強体が構成されている。第１補強板８は折曲部１１でほぼ直角に折曲しており、かつ、両側縁部１２が長手方向に沿って第１金属板６の内面に接合されている。第２補強板９も折曲部１１でほぼ直角に折曲しており、かつ、両側縁部１３が長手方向に沿って第２金属板７の内面に接合されている。
【００１９】
図２のように、フロントサイドメンバ２は、補強体が配設された補強部１５と、補強体が配設されていない非補強部１４とにより構成されている。非補強部１４は、車両組立状態で車両前部側となる位置に設けられ、中空外郭体の内部を空洞化した形状となっている。
【００２０】
フロントサイドメンバ２は、後述する予備成形体２０を液圧成形により中空成形体に膨出成形した後、図示しない裁断工程などを経て製造される。図４は、上述した２枚の金属板６、７、および２枚の補強板８、９により構成された予備成形体２０を示す図である。図５は、図４のＸ−Ｘ線に沿った予備成形体２０の断面図であり、図６は、図４のＹ−Ｙ線に沿った予備成形体２０の長手方向の断面図である。
【００２１】
図４のように、予備成形体２０は後述する液体注入部２１から長手方向に向かって、その直角断面方向の幅は漸増していく形状をなしており、図５のように、上述した第１金属板６と第２金属板７および、２枚の補強板８、９により構成されている。２枚の金属板６、７は互いに重ね合せた状態で、両側縁部１０を含め全周縁部で互いに接合されている。２枚の補強板８、９は、液圧成形後には図３に示すように折曲することとなるが、予備成形体２０の段階では折曲しておらず、平板形状をなしており、互いに重ね合わせた状態で、２枚の金属板６、７の間にサンドイッチ状に挟み込まれている。
【００２２】
予備成形体２０は、長手方向でいくつかの部分に分けることができ、補強板８、９からなる予備補強体が配設される予備補強部２２と、高圧な液体が注入される液体注入部２１と、その間に長手方向で予備補強部２２と液体注入部２１との間に位置する所定長さの中間部２３とを有している。中間部２３および液体注入部２１には、２枚の金属板６、７の間に補強板８、９を配設しない。図２に示した補強部１５は、予備補強部２２から形成され、非補強部１４は中間部２３から成形される。
【００２３】
図５および図６を参照しながら予備成形体２０の形成手順を説明する。まず一対の補強板８、９を、互いに板幅方向にオフセットして重ね合わせた状態で、その板幅方向中央部に位置する交差位置１１で、長手方向に沿って互いに接合する。この接合はレーザーによる重ね溶接、アーク溶接によるスロット溶接またはプラグ溶接、あるいは、接着、カシメなどにより行うことができる。次に第２補強板９の両側縁部１３を長手方向に沿って第２金属板７の内面に接合する。次いでこれら補強板８、９を挟み込むように第１金属板６を第２金属板７に重ね合わせて、第１金属板６と第１補強板８ａの両側縁部１２とを接合する。次いで互いに重ね合わせた金属板６、７の両周縁部１０を全周に渡って接合し、予備成形体２０を得る。この接合は例えばレーザー溶接やアーク溶接あるいは、接着剤などで行うことができ、この全周接合により両金属板６、７の内部が密閉状態に保たれる。
【００２４】
このように形成される予備成形体２０に対し、図７、図８、図９に示すような上型２４、下型２５を用いて液圧成形を行う。なお、図７は図４のＸ−Ｘ線に沿う断面に、図８は図４のＹ−Ｙ線に沿う断面に対応している。上下型２４、２５には、フロントサイドメンバ２の断面方向が略矩形断面で、長手方向に向かって断面が漸増する外形形状がキャビティ２６、２７として形成されおり、上下型２４、２５の分割面２８はその矩形断面の対角線上にある。
【００２５】
下型２５には液体注入ノズル２９が取り付けられている。ノズル２９には、下型２５に形成された液体通路３０および液体通路３０に接続する高圧ホース３４を経由して、図示しない高圧発生装置から高圧の液体が供給される。ノズル２９を受容するように、予備成形体２０の液体注入部２１は、予め中空形状に形成されるとともに、ノズル２９が勘合する勘合孔３１が第２金属板７に形成されている。
【００２６】
上型２４および下型２５には予備成形体２０の中空形状をなす液体注入部２１の形状が収まる凹溝３２、３３がそれぞれ形成され、凹溝３２、３３と金型のキャビティ２６、２７との間には凹溝３２、３３からキャビティ２６、２７へ向かって断面積が徐々に拡大するように傾斜する傾斜面３２ａ、３３ａがそれぞれ形成されている。これら凹溝３２、３３、および傾斜面３２ａ、３３ａは、金属板６、７の合わせ面、つまり上型２４と下型２５の分割面２８に対して実質的に均等に形成されており、分割面２８を挟んでほぼ同じ面積（容積）となるように設定されている。分割面２８上に、矩形形状をなすフロントサイドメンバ２の対角線、ノズル２９の噴射軸線、更には予備補強体の中心を含む補強板８、９の合わせ面が配置するように設定されている。つまり、補強板８、９の中心と中間部２３の中心とを分割面２８上の同一位置に設定している。
【００２７】
図７に示すように、予備成形体２０を上型２４と下型２５の間で狭持型締めした状態で、高圧発生装置により発生された高圧な液体を、高圧ホース３４および液体通路３０を経由してノズル２９へ供給し、ノズル２９により予備成形体２０に形成した勘合孔３１から液体注入部２１の内部へ注入する。この高圧な液体は、互いに重ね合わせた２枚の金属板６、７の周縁部１０が全周に渡って互いに接合されているため予備成形体２０の外部へ漏れ出すことはない。
【００２８】
この液体の高い圧力により、予備成形体２０がノズル２９に近い部分から予備補強部２２へ向かって徐々に膨出変形していくこととなる。この液圧成形により図２、図３に示すように金属板６、７および、補強板８、９が適正な形状へ変形していくことになるが、それは以下のような理由によるものである。中空成形による変形過程において、まず予備変形部４７、３５が凹溝３２、３３の内面に沿うように変形していく。これら予備変形部４７、３５はそのノズル側が予め凹溝３２、３３の内面に沿うように形成されており、かつ、分割面２８に対して上下均等（相似形）に設定されているため、ノズル側の部分の形状に追従するように、長手方向および、長手方向に直交する方向に関して均一かつスムーズに凹溝３２、３３に沿って膨出変形していく。また、傾斜面部３２ａ、３３ａの部分で断面積が徐々に拡大するように設定されているため、金属板６、７はキャビティ２６、２７の内面に沿う形状へとスムーズに膨出変形していく。
【００２９】
従って、予備補強部２２が変形し始める段階では、既に中間部２３周辺部分の金属板６、７がキャビティ２６、２７の壁面に沿うように膨出変形しており、この部分の形状に追従するように、まず予備補強部２２の中間部２３寄りの金属板６、７の部分が適切に膨出変形していく。金属板６、７の変形に応じて、金属板６、７に接合する補強板８、９が変形・折曲していく。このように予備補強部２２の変形が良好に進行していくように、中間部２３の長手方向長さが充分に長く設定されている。補強板８、９の変形に応じて、これら補強板８、９によって仕切られら長手方向に延びる４つの空間が、その形状が個々にばらつくことなく、均一に形成されていき、これら空間から金属板６、７の内面に均等な液圧Ｐが作用することにより、これら金属板６、７がキャビティ２６、２７の壁面に沿う最終的な矩形断面形状で、かつ長手方向で断面の大きさが漸次変化した形状へと膨出変形していく。成形後の金型断面を図９に示す。
【００３０】
上述したように、液圧成形後の中空外郭体の対角線が、上型２４および下型２５の分割面２８上に位置し、分割面２８に沿って金属板６、７を互いに接合したフランジ状の両側縁部１０を配置しているため、金属板６、７が液体により徐々に膨出変形していく過程において、フランジ状をなす両側縁部１０がスムーズにキャビティ２６、２７側へと引き込まれて流入していく。このため、金属板６、７をスムーズに膨出変形させていくことができる。
【００３１】
変形完了後に、液体の圧力を除去し、上型２４および下型２５内から中空成形体３６を取り出し、長手方向両端の不要部分を切除することにより、上述した断面が複数に仕切られた補強部１５と非補強部１４で構成された断面積が漸増するフロントサイドメンバ２を得ることができる。
【００３２】
フロントサイドメンバ２によれば、前面衝突時には、まず非補強部１４が速やかに潰れ、次に補強体で断面を仕切っている補強部１５が潰れる。補強部１５は断面を仕切る補強板８、９により断面内に稜線が増えるため、高強度となり高反力が得られる。さらにフロントサイドメンバ２では、補強体を有した略矩形部の断面形状が、長手方向で均等に漸増するように構成された外形形状をなしているため、この反力は潰れが進行するに従い大きくなるとともに、潰れた部分が重なりにくくなるため、潰れ残りが少なくなり有効な潰れストロークが増えるため、衝突時の初期反力を抑えつつ、全体として衝突エネルギー吸収効率を効果的に高めることができる。さらに対角線方向にフランジが突出することにより、潰れモードが安定する。また、平板部８ａ、８ｂが互いに直交するように交差する形状となっているため、長手方向に直交する方向の荷重に対しても高い強度が得られる。
【００３３】
実施の形態１では、２枚の補強板８、９により構成しているが、本発明はこれに限られるものではない。例えば図１０に示すように、金属板６、７からなる中空外郭体の内部を２つの空間に仕切る一枚の補強板３７を構成してもよい。また、同様に図１１のように、金属板６、７からなる中空外郭体の内部を３つの空間に仕切る２枚の補強板３８、３９を構成してもよい。図１０および図１１に示す補強体を有した中空外郭体は、それぞれ図１２と図１３に示すような構成の予備成形体４０、４１を用いて液圧成形を行うことにより形成できる。さらにこれらの断面形状は長手方向の途中で任意に変化させることが可能であり、求められるエネルギー吸収性能に応じて自由に組合せ選択も可能である。
【００３４】
なお、以上の説明では、フロントサイドメンバ２として説明したが、車両後部に設置され、車両後面からの衝突に対してエネルギー吸収を行うリアサイドメンバ（図示せず）にも適用できることは言うまでもない。
【００３５】
［実施の形態２］
次に、本発明の実施の形態２を説明する。この実施の形態は、図１に示した自動車車体１のフロントサイドメンバ２の前端からさらに前方方向に延びるクラッシュボックス３に本発明を適用したものである。なお、この実施の形態の説明をするに当たって、実施の形態１と重複する構成、およびその構成の作用、効果についての説明は適宜省略する。
【００３６】
図１において、クラッシュボックス３はフロントサイドメンバ２の前端に左右略対称に配置されており、左右のクラッシュボックス３にはさらにその前方に位置されるバンパー４が連結されている。前面衝突時のエネルギーはまずバンパー４に伝わり、それが左右のクラッシュボックス３に伝達され、さらにフロントサイドメンバ２に伝わる構造となっている。
【００３７】
図１４はクラッシュボックス３の斜視図である。クラッシュボックス３は、２枚の金属板５１、５２からなる中空外郭体をなしている。中空外郭体は、断面略矩形形状で、長手方向に漸次断面を拡大しながら延びる閉断面構造をなしている。中空外郭体の内部には、互いに交差する一対の補強板５３、５４を備えた断面略十字状をなす補強部５６が設けられている。これら補強板５３、５４によって、中空外郭体の内部が長手方向に延び、かつ断面空間の大きさが漸増する４つの空間に仕切られている。中空外郭体の両側縁部５５は、中空外郭体の矩形部分から突出するフランジ形状を呈しており、その方向は矩形部分の対角線上に延びるように突出しており、その突出端近傍で両金属板５１、５２が互いに接合されている。
【００３８】
クラッシュボックス３は、後述する予備成形体５７を液圧成形することにより得られる中空成形体から、裁断加工等を経て製造される。図１５は予備成形体５７の斜視図である。予備成形体５７は中空外郭体となる２枚の金属板５１、５２と、補強部５６となる２枚の補強板５３、５４とにより構成されており、その断面形状は図５に示した形状と同様である。しかし本実施の形態では図１５に示すように、予備成形体５７が、液体注入部５８から非補強部５９、補強部５６へと、順次、長手方向と直交する側の幅は漸増していくが、中央から後方へは漸減していく、つまり中央で前後対称形状をもった予備成形体５７であり、後述するように、左右のクラッシュボックスを中央で繋げた２ヶ取り用の形状をなしている。
【００３９】
予備成形体５７を液圧成形により膨出変形する方法は、実施の形態１と同様である。しかしながら、本実施の形態では、クラッシュボックス３の外郭形状に対応したキャビティが形成された上型と下型には、図１６に示すように、断面が漸増する右側用クラッシュボックス６１と、断面が漸減する左側用クラッシュボックス６２が、中央変化部６３で組み合わされた外郭形状で、金型のキャビティが形成されているのが特徴である。
【００４０】
予備成形体５７の液体注入部５８から、２枚の金属板５１、５２と補強板５３、５４とで仕切られる各空間部に液体を注入すると、液体注入部５８近傍は実施の形態１と同様の構成となっているため、補強板で仕切られる各空間に均等に液圧を作用させることができ、予備成形体５７を膨出変形させることで中空成形体が得られる。中空成形体の前後の不要部分を裁断すると、図１６に示したような、右側用クラッシュボックス６１と、左側用クラッシュボックス６２が、中央変化部６３で繋がった中間成形体６０が得られ、これをさらに中央で２分割することにより、一度にクラッシュボックス３の左右用２部品を同時に得ることができる。
【００４１】
この製造方法によって得られた中空成形体から図１４に示したクラッシュボックス３が製造される。クラッシュボックス３によれば、補強部５６は断面を仕切る補強板５３、５４により断面内に稜線が増えるため、高強度となり高反力が得られる。さらに補強板を有した略矩形部分の断面形状が、長手方向で均等に漸増するように構成された外形形状をなしているため、その反力は潰れが進行するに従い大きくなるとともに、潰れた部分が重なりにくいため、潰れ残りが少なくなり有効な潰れストロークが増える。従って、全体として衝突エネルギー吸収効率を効果的に高めることができる。また、断面が漸増する右側用クラッシュボックス６１と、断面が漸減する左側用クラッシュボックス６２を中央で繋げた外郭形状で金型のキャビティを形成することにより、一回の成形で左右部品が同時に成形でき、生産性や材料歩留りが向上するとともに、成形体が膨出変形しやすい滑らかな形状となるため、成形が容易に行えるという効果も得られる。
【００４２】
なお、クラッシュボックス３においても、実施の形態１で、図１０、図１１に示したような補強板の数や構造を、要求性能に応じて任意に選択、適用できることは言うまでもない。
【００４３】
［実施の形態３］
この実施の形態は、図１に示す自動車車体１のサイドメンバ２の上方に位置するフードレッジ５に本発明を適用したものである。
【００４４】
図１７は、フードレッジ５の斜視図であり、図１８は図１７のＱ方向からの矢視図を示す。図１７に示すフードレッジ５の形状は、２枚の金属板７１、７２からなる中空外郭体をなしている。中空外郭体は、断面略矩形で、長手方向に漸次断面積を拡大しながら延びる閉断面構造をなしているが、その拡大方向が、図１の車両組み付け状態で、車両内側と車両下方方向には変化がなく、車両外側と車両上方には漸次拡大していく形状を有している。中空外郭体の内部には、互いに交差する一対の平板部７３ａ、７３ｂを備えた断面略十字状をなす補強板７３、７４が設けられている。これら補強板７３、７４によって、中空外郭体の内部が長手方向に延び、かつ断面空間の大きさが漸増する４つの空間に仕切られている。中空外郭体の両側縁部７５は、中空外郭体の矩形部分から突出するフランジ形状を呈しており、その方向は矩形部分の対角線上に延びるように突出しており、その突出端近傍で両金属板７１、７２が互いに接合されている。
【００４５】
フードレッジ５は、図１９に示す予備成形体７７を、実施の形態１と同様、液圧成形することにより得られる中空成形体から裁断加工などを経て製造される。図１９は予備成形体７７の斜視図である。予備成形体７７は中空外郭体となる２枚の金属板７１、７２と、補強部７６となる２枚の補強板７３、７４とにより構成されており、断面形状としては図５に示すものと同様である。しかし本実施の形態では、図１９に示すように、予備成形体７７が、液体注入部７８から非補強部７９、補強部７６へと、順次、長手方向と直交する側の幅が一方向だけ（図１９では図の手前側）に漸増していく非対称形状をもった予備成形体７７である。
【００４６】
予備成形体７７を液圧成形により膨出変形する方法は、実施の形態１と同様であるが、前述したように、フードレッジ５の外郭形状は断面略矩形で、長手方向に漸次断面を拡大しながら延びる閉断面構造をなしている。その拡大方向は、車両組み付け状態で、車両内側と車両下方方向には変化がなく、車両外側と車両上方には漸次拡大していく形状となっているため、図２０に示すようにこの形状に対応して特定方向に断面が漸増したキャビティ８２、８３が形成された上型８０および下型８１を用いる。
【００４７】
予備成形体７７の液体注入部７８から、２枚の金属板７１、７２と補強板７３、７４とで仕切られる各空間部に液体を注入すると、液体注入部７８近傍は実施の形態１の場合と同様の構成となっているため、補強板で仕切られる各空間に均等に液圧を作用させることができ、予備成形体７７を膨出変形させることで中空成形体が得られる。
【００４８】
この製造方法によって得られた中空成形体から図１７に示したフードレッジ５が製造される。フードレッジ５も前述のサイドメンバやクラッシュボックスと同様に、高強度な補強部７６は高反力が得られる。さらに補強板７３、７４を有した略矩形部の断面形状が、長手方向で特定方向に漸増する外形形状をなしているため、軸方向に作用する荷重に対する反力も漸増す。かつ、潰れ残りが少なくなり有効な潰れストロークが増えるため、全体として衝突エネルギー吸収効率を効果的に高めることができる。またそれと同時に、フードレッジ５は車両組み付け状態で、車両内側と車両下方方向には断面拡大をなくせるため、エンジンやタイヤ、サスペンションなどとの干渉が避けられ、車両部品のレイアウトがしやすい。
【００４９】
なお、フードレッジ５においても、サイドメンバについての実施の形態１で、図１０、図１１に示したような補強板の数や構造を任意に選択適用できることはもちろんである。また逆に、本実施の形態に示したような、補強部を有し、かつ特定方向にのみ断面が拡大する形状を、前述のサイドメンバやクラッシュボックスに適用してもよい。この場合は、斜め衝突などの際、必要となる特定方向に対して高強度となり高反力が得られるサイドメンバやクラッシュボックスの製造が可能となる。
【００５０】
［実施の形態４］
この実施の形態は、図１の自動車車体１の前端部もしくは、図示しない後端部で、左右方向に延びるバンパー４に本発明を適用したものである。
【００５１】
図２１はバンパー４の斜視図、図２２は図２１のＲ方向からの矢視図を示す。バンパー４は、略矩形断面の中空外郭体を形成する金属板９１、９２の内部が、複数の補強板９３、９４で断面が仕切られており、かつ、その複数の補強板９３、９４の交差位置９６が、中空外郭体の中心位置からオフセットした断面形状を有している。また断面形状は、図１に示す車両組み付け状態で、車両の左右中心方向に向かうに従い、車両前方部９８および、車両上方部９７に拡大する形状を有したバンパー４である。
【００５２】
予備成形体９５の断面図を図２３に示す。これは、実施の形態３とほぼ同様の予備成形体９５であるが、第１の補強板９３と第２の補強板９４との断面方向の幅が異なり、かつ互いに接合された交差位置９６が、２枚の金属板９１、９２の中心位置からオフセットした予備成形体９５である。その後の製造方法は実施の形態３の場合と同様である。
【００５３】
なお、本実施の形態では、液圧成形後、矩形部分の対角線８９上にある車両前方側のフランジ９９に曲げ加工を施し、車両前側壁８８と面一となるように形成している。
【００５４】
本発明により得られる車両左右中心に向かって断面が拡大する形状を有したバンパー４により、ポール衝突やオフセット衝突など、バンパー中央部あるいは、バンパーの片側に衝突入力が作用する場合に、左右のクラッシュボックス３間での折れ曲がりを防止でき、また、バンパー４連結されているクラッシュボックス３やサイドメンバ２へ荷重を良好に伝達することができる。なお、複数の補強板９３、９４の交差位置は、バンパー４の高さ方向の位置と、左右のクラッシュボックス３やサイドメンバ２の高さ方向の位置に応じて、任意に設定が可能であり、バンパー４からの荷重をサイドメンバ２に良好に伝達するように適宜設定ができ、構造設計の自由度が高い。またバンパー４の補強体は、実施の形態１の場合と同様に、図１０、図１１で示したような補強板の数や構造を適宜、適用できる。
【００５５】
以上のように具体的な実施の形態１〜４に基づいて本発明を説明してきたが、本発明は以上の実施の形態に限定されるものではなく、その技術的思想を逸脱しない範囲で、種々の変形、変更は可能である。例えば、重ね合わせる金属板や補強板の材質、板厚などは、図示された形態に限定されるものではなく、要求性能に応じて任意に設定できる。
【００５６】
なお、各請求項に記載した発明は次のような効果を奏する。
【００５７】
請求項１に記載の液圧成形における予備成形体によれば、この予備成形体を液圧成形することにより、互いに重ね合わせた２枚の金属板により中空外郭体が成形されるとともに、この中空外郭体は長手方向に断面積が漸次変化する中空断面を仕切る補強体を同時に成形することができ、しかもその製造が容易である。加えて、補強体へと変形する予備補強体は、変形前の金属板に予め接合しておくことができるので、その接合作業が容易であるとともに、補強体のレイアウトおよび形状の自由度も高い。
【００５８】
請求項２に記載の液圧成形における予備成形体によれば、成形後の中空外郭体の内部が平板部によって長手方向に伸びる４つの空間に仕切られた形状となり、強度・剛性に優れたものとなる。
【００５９】
請求項３に記載の液圧成形における予備成形体によれば、この予備成形体から成形される中空成形体は、長手方向に断面積が漸次変化するとともに、中空外郭体の対向面を互いに連結する補強体により、強度・剛性に優れたものとなり、衝撃荷重を有効に吸収・分散することができる。また補強体を長手方向の一部にのみ配置することも可能で、レイアウトの自由度も高い。
【００６０】
請求項４に記載の液圧成形における予備成形体によれば、予備成形体から得られる製品の補強性は優れたものとなる。
【００６１】
請求項５に記載の液圧成形における予備成形体によれば、得られる製品における補強板間で荷重を分散させることができ、補強性能に優れている。
【００６２】
請求項６に記載の中空成形体の液圧成形方法によれば、液体注入部と予備補強部との間に予備補強体が配置されていない中間部を設けているため、上記液体注入部へ高圧な液体を注入すると、まず中間部から徐々に変形していき、これに追従するように予備補強部が変形していく。従って補強体により仕切られた複数の空間の形状がばらつくことなく適正に形成され、これら空間に作用する均等な液圧により金属板を適正に膨出変形させていくことができる。このように、２枚の金属板を、長手方向に断面が漸次変化する中空形状に膨出変形する中空成形時に、断面を複数に仕切る補強体を同時に成形することが可能となり、高強度で、かつエネルギー吸収性能に優れた中空成形体を容易に製造することができる。
【００６３】
請求項７に記載の中空成形体の液圧成形方法によれば、液圧成形により金属板が徐々に膨出変形していくに従って、フランジ状の両側縁部を金型のキャビティ内へスムーズに導き入れることができ、金属板の膨出変形を良好に行わせることができる。また対角線方向にフランジが突出することにより、エネルギー吸収効率に優れた部材が得やすくなる。
【００６４】
請求項８に記載の中空成形体の液圧成形方法によれば、例えば一枚の補強板からなる第１の予備補強体と、複数の補強板からなる第２の予備補強体と、を一つの予備成形体の長手方向で異なる位置に設けることもでき、性能に応じた設計が可能となる。
【００６５】
請求項９に記載の中空成形体の液圧成形方法によれば、液圧成形後の中空成形体の内部が２枚の補強板により上下左右に仕切られることとなり、上下・左右のどちらの方向にも、また軸方向にも高強度な中空成形体が得られる。
【００６６】
請求項１０に記載の中空成形体の液圧成形方法によれば、上記２枚の補強板により内部が４つの均等に仕切られた中空成形体を得ることが可能となる。
【００６７】
請求項１１に記載の中空成形体の液圧成形方法によれば、例えば中空成形体の断面が長手形状の場合であっても、上記２枚の補強板により中空成形体の断面を均等に、または任意の位置で仕切ることができる。
【００６８】
請求項１２に記載の中空成形体の液圧成形方法によれば、長手方向で断面が変化するとともに、内部に補強板を有した中空成形体を容易に得ることができる。
【００６９】
請求項１３に記載の中空成形体の液圧成形方法によれば、例えば左右部品や複数部品を同時に得ることができ、製造に係る生産性や経済性が向上する。
【００７０】
請求項１４に記載の中空成形体の液圧成形方法によれば、補強材により断面内に稜線が増えるため、高強度となり高反力が得られる。また補強材を有した中空部の断面積が長手方向で均等に漸次拡大していく一体構造部材が形成可能となり、軸圧縮時に潰れ残りが少なくなるため、衝突エネルギー吸収効率を効果的に高めることができる。また補強材を中空成形体の長手方向の任意の位置に容易に配置することが可能となり、エネルギー吸収性能を設計する上で、形状やレイアウトの自由度が高くなる。
【００７１】
請求項１５に記載の中空成形体の液圧成形方法によれば、斜め衝突などの際の必要となる特定方向に対して高強度となり高反力が得られる。
【００７２】
請求項１６に記載の中空成形体の液圧成形によれば、必要となる特定方向に対して高強度となり高反力が得られる。またエネルギー吸収性能を設計する上で、形状やレイアウトの自由度が高くなる。
【００７３】
請求項１７に記載の中空成形体の液圧成形によれば、バンパー中央部あるいは、バンパーの片側に衝突入力が作用する場合に、左右のクラッシュボックス間での折れ曲がりを防止でき、また、車体へ荷重を良好に伝達することができる。
【図面の簡単な説明】
【図１】自動車車体の前部の骨格を示す斜視図である。
【図２】フロントサイドメンバの斜視図である。
【図３】図２のＰ方向からの矢視図である。
【図４】２枚の金属板および２枚の補強板により構成された予備成形体を示す図である。
【図５】図４のＸ−Ｘ線に沿った予備成形体の断面図である。
【図６】図４のＹ−Ｙ線に沿った予備成形体の長手方向の断面図である。
【図７】実施の形態１に係る金型および予備成形体の液圧成形前の断面図である。
【図８】図７のＺ−Ｚ線に沿う断面図である。
【図９】実施の形態１に係る金型および予備成形体の液圧成形後の断面図である。
【図１０】実施の形態１に対する他の例を示す断面図である。
【図１１】実施の形態１に対するさらに他の例を示す断面図である。
【図１２】実施の形態１に対する他の例の予備成形体を示す断面図である。
【図１３】実施の形態１に対するさらに他の例の予備成形体を示す断面図である。
【図１４】実施の形態２に係るクラッシュボックスの斜視図である。
【図１５】実施の形態２に係る予備成形体の斜視図である。
【図１６】実施の形態２に係る中間成形体の斜視図である。
【図１７】実施の形態３に係るフードレッジの斜視図である。
【図１８】図１７のＱ方向からの矢視図である。
【図１９】実施の形態３に係る予備成形体の斜視図である。
【図２０】実施の形態３に係る金型および予備成形体の液圧成形後の断面図である。
【図２１】実施の形態４に係るバンパーの斜視図である。
【図２２】図２１のＲ方向からの矢視図である。
【図２３】実施の形態４に係る予備成形体の断面図である。
【符号の説明】
１…自動車車体前端部
２…フロントサイドメンバ
３…クラッシュボックス
４…バンパー
５…フードレッジ
６、７、５１、５２、７１、７２、９１、９２…金属板
８、９、３７、３８、３９、５３、５４、７３、７４、９３、９４…補強板
１０、１２、１３、５５、７５…両側縁部
１１、９６…折曲部
１４、５９、７９…非補強部
１５、５６、７６…補強部
２０、４０、４１、５７、７７、９５…予備成形体
２１、５８、７８…液体注入部
２２…予備補強部
２３、５９、７９…中間部
２４、２５、８０、８１…上下型
２６、２７、８２、８３…キャビティ
２８…分割面
２９…ノズル
３０…液体通路
３１…勘合孔
３２、３３…凹溝
３２ａ、３３ａ…傾斜面
３４…高圧ホース
３５、４７…予備変形部
３６…中空成形体
６０…中間成形体
６１…右側用クラッシュボックス
６２…左側用クラッシュボックス
６３…中央変化部
７３ａ、７３ｂ…平板部
８８…車両前側壁、
９６…交差位置、
９７…車両上方部、
９８…車両前方部、
９９…フランジ。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for hydroforming a preform and a hollow molded body in hydroforming.
[0002]
[Prior art]
A vehicle body structural member that functions as a shock absorbing member, such as a front side member or a crash box, generally has a hollow shell shape suitable for absorbing shock. This vehicle body structural member has a certain degree of strength, and in order to effectively absorb impact, a reinforcing plate is arranged so as to partition the inside thereof, and the cross-sectional shape gradually increases in the longitudinal direction. It is configured as follows. The manufacture of such a vehicle body structural member is performed by extrusion molding.
[0003]
Patent Literature 1 below discloses a technique for forming a vehicle body structural member from an extruded material. The vehicle body structural member disclosed in Patent Literature 1 is a left and right crash box whose axis extends in the front-rear direction at the front of the vehicle. The crash box is formed from extruded aluminum.
[0004]
In order to manufacture the crash box, first, a reinforcing plate that partitions the inside of the rectangular hollow portion into a cross shape is arranged in the rectangular hollow portion, and a flange that protrudes outward from the outer surface of the rectangular hollow portion is integrally extruded and formed. The flange is cut so that the flange width gradually increases from the front side to the rear side of the flange.
[0005]
Extrusion molding by such a procedure allows a large axial compression load to be obtained mainly by the reinforcing plate and the rectangular hollow portion arranged so as to partition the inside, and the axial compression load at the flange portion where the flange width gradually increases. Can be gradually increased.
[0006]
[Patent Document 1]
JP-A-2002-155981
[0007]
[Problems to be solved by the invention]
However, in conventional body structural members, the rectangular hollow part that mainly absorbs impact energy has a constant cross-sectional area, and the energy absorption performance is controlled by gradually increasing only the flange width of the flange part. The degree is extremely narrow. In addition, since the rectangular hollow portion has a constant cross-sectional area, there is a problem that uncrushed portions are generated at the time of axial compression, so that an effective crushing stroke is shortened and energy absorbing performance may be insufficient.
[0008]
In addition, when an aluminum extruded material is used, since the reinforcing plate for partitioning the cross section is formed by extrusion molding, the rectangular hollow portion has a constant cross-sectional area in the longitudinal direction, and the reinforcing plate for partitioning the cross section can be freely positioned at any position in the longitudinal direction. It is difficult to dispose them in a space, and there is a problem that the degree of freedom in shape and layout is low in designing the energy absorption performance.
[0009]
The present invention has been made in order to solve the above-described various problems in the related art, and has a large degree of freedom in design, a pre-formed body and a hollow formed body having a structure in which uncrushed portions are unlikely to occur during axial compression. The purpose of the present invention is to provide a hydraulic forming method.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems and achieve the object, a preform in the hydroforming according to the present invention has at least two metal plates superimposed on each other, and in a longitudinal direction of the two metal plates. A preform in hydraulic forming in which the two side plates along which the two metal plates are joined are joined together, and the two metal plates are swelled and deformed into a hollow shell extending in the longitudinal direction by hydraulic forming. Between the metal plates, preliminary reinforcing members joined to the inner surfaces of the two metal plates are interposed in advance, and the width of the preliminary reinforcing members in the cross-sectional direction gradually changes in the longitudinal direction of the metal plate. The pre-reinforcement is deformed by the hydraulic forming into a reinforcement that extends in the longitudinal direction inside the hollow shell and partitions the inside into a plurality of spaces whose cross-sectional areas gradually change. It is characterized by the following.
[0011]
In addition, in order to solve the above-mentioned problems and achieve the object, a method of hydraulically forming a hollow molded body according to the present invention includes a method of forming a first metal plate between a first metal plate and a second metal plate stacked on each other. A pre-reinforcement portion provided with a pre-reinforcement body bonded to the inner surfaces of the plate and the second metal plate, a liquid injection portion into which a liquid is injected at the time of hydroforming, the first metal plate, An intermediate portion which is located between the preliminary reinforcing portion in the longitudinal direction of the second metal plate and the liquid injection portion and is not provided with the preliminary reinforcing member, and wherein the first metal plate and the second metal The two side edges along the longitudinal direction of the plate are joined together to form a preform, and the preform is sandwiched between an upper mold and a lower mold in which a cavity is formed, and a liquid injection portion of the preform is formed. , And the hollow molded body is bulged.
[0012]
【The invention's effect】
According to the preform in the hydroforming according to the present invention, the hollow shell can be formed by two metal plates that are overlapped with each other by hydroforming, and at the same time, the cross section of the hollow shell is changed in the longitudinal direction. In addition, it is possible to form a reinforcing body for partitioning such that the sectional area gradually changes, and it is easy to manufacture the reinforcing body. In addition, since the pre-reinforcing body that deforms into the reinforcing body can be previously bonded to the metal plate before deformation, the bonding operation is easy, and the degree of freedom in the layout and shape of the reinforcing material is high. Become.
[0013]
According to the hydraulic forming method of the hollow molded body of the present invention, since the intermediate portion where the preliminary reinforcing member is not provided between the liquid injection portion and the preliminary reinforcing portion, the high-pressure liquid is supplied to the liquid injection portion. Upon injection, first, the intermediate portion gradually deforms, and the preliminary reinforcing portion deforms so as to follow this. Therefore, the shape of the plurality of spaces partitioned by the reinforcing member is appropriately formed without variation, and the metal plate can be appropriately swelled and deformed by uniform liquid pressure acting on these spaces, and high strength is obtained. A hollow molded article excellent in energy absorption performance can be easily manufactured.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0015]
FIG. 1 is a perspective view showing a skeleton of a front portion of an automobile body 1. A front side member 2 extending in the front-rear direction is provided on the left and right at the front of the vehicle body 1. A crash box 3 is connected to the front ends of the left and right front side members 2, and a front bumper 4 is connected via the crash box 3. Above the left and right front side members 2, left and right hood ledges 5 are also provided. For a collision from the front of the vehicle body, energy is mainly absorbed by these members.
[0016]
[Embodiment 1]
First, a first embodiment in which the present invention is applied to a front side member 2 as a vehicle body structure will be described. FIG. 2 is a perspective view of the front side member 2, and FIG. 3 is a view as seen from a direction P in FIG. 2.
[0017]
The front side member 2 has a hollow shell formed by combining the first metal plate 6 and the second metal plate 7. The hollow shell has a hollow cross-sectional shape, and has a substantially rectangular closed cross-sectional structure whose cross-sectional area gradually increases as it extends in the longitudinal direction. As shown in FIG. 3, the first metal plate 6 and the second metal plate 7 are each bent substantially in an L shape to form two side walls of the hollow shell. These metal plates 6 and 7 are joined to each other along the longitudinal direction at two locations on both side edges 10. The side edges 10 have a flange shape protruding outward from the rectangular portion of the hollow shell, and project in a direction diagonally extending from the rectangular portion. 7 are joined together.
[0018]
Inside the hollow shell, a first reinforcing plate 8 and a second reinforcing plate 9 are bent in an L-shape and joined together at a bent portion 11 extending in the longitudinal direction, thereby reinforcing a cross section having a substantially cross shape. The body is made up. The first reinforcing plate 8 is bent substantially at a right angle at the bent portion 11, and both side edges 12 are joined to the inner surface of the first metal plate 6 along the longitudinal direction. The second reinforcing plate 9 is also bent substantially at a right angle at the bent portion 11, and both side edges 13 are joined to the inner surface of the second metal plate 7 along the longitudinal direction.
[0019]
As shown in FIG. 2, the front side member 2 includes a reinforcing portion 15 on which a reinforcing member is provided and a non-reinforcing portion 14 on which no reinforcing member is provided. The non-reinforcing portion 14 is provided at a position on the vehicle front side in a vehicle assembled state, and has a shape in which the inside of the hollow outer body is hollowed out.
[0020]
The front side member 2 is manufactured through a cutting process (not shown) after a later-described preformed body 20 is bulged into a hollow molded body by hydraulic forming. FIG. 4 is a view showing a preformed body 20 constituted by the two metal plates 6 and 7 and the two reinforcing plates 8 and 9 described above. FIG. 5 is a cross-sectional view of the preform 20 taken along the line XX of FIG. 4, and FIG. 6 is a longitudinal cross-sectional view of the preformed body 20 taken along the line YY of FIG. .
[0021]
As shown in FIG. 4, the preform 20 has a shape in which the width in the perpendicular cross-section direction gradually increases in the longitudinal direction from a liquid injection portion 21 described later, and as shown in FIG. It is composed of one metal plate 6, a second metal plate 7, and two reinforcing plates 8, 9. The two metal plates 6 and 7 are joined to each other at the entire periphery including the both side edges 10 in a state of being overlapped with each other. The two reinforcing plates 8 and 9 are bent as shown in FIG. 3 after the hydroforming, but are not bent at the stage of the preform 20 and have a flat plate shape. It is sandwiched between two metal plates 6 and 7 in a sandwich shape in a state of being overlapped with each other.
[0022]
The preform 20 can be divided into several parts in the longitudinal direction, and a prereinforcing part 22 in which a prereinforcing body composed of the reinforcing plates 8 and 9 is disposed, and a liquid injecting part into which high-pressure liquid is injected. 21 and an intermediate portion 23 of a predetermined length located between the preliminary reinforcing portion 22 and the liquid injection portion 21 in the longitudinal direction therebetween. The reinforcing plates 8 and 9 are not provided between the two metal plates 6 and 7 in the intermediate portion 23 and the liquid injection portion 21. The reinforcing portion 15 shown in FIG. 2 is formed from the preliminary reinforcing portion 22, and the non-reinforcing portion 14 is formed from the intermediate portion 23.
[0023]
The procedure for forming the preform 20 will be described with reference to FIGS. First, in a state where the pair of reinforcing plates 8 and 9 are overlapped with each other offset in the plate width direction, they are joined to each other along the longitudinal direction at an intersecting position 11 located at a central portion in the plate width direction. This joining can be performed by lap welding by laser, slot welding or plug welding by arc welding, bonding, caulking, or the like. Next, both side edges 13 of the second reinforcing plate 9 are joined to the inner surface of the second metal plate 7 along the longitudinal direction. Next, the first metal plate 6 is superimposed on the second metal plate 7 so as to sandwich the reinforcing plates 8 and 9, and the first metal plate 6 and the side edges 12 of the first reinforcing plate 8 a are joined. Next, the two peripheral edges 10 of the metal plates 6 and 7 which are superimposed on each other are joined over the entire periphery to obtain a preform 20. This joining can be performed by, for example, laser welding, arc welding, an adhesive or the like, and the inside of both metal plates 6 and 7 is kept in a sealed state by this full-circumference joining.
[0024]
The preformed body 20 thus formed is subjected to hydraulic forming using an upper mold 24 and a lower mold 25 as shown in FIGS. 7, 8 and 9. FIG. 7 corresponds to a cross section taken along line XX of FIG. 4, and FIG. 8 corresponds to a cross section taken along line YY of FIG. The upper and lower dies 24 and 25 are formed with cavities 26 and 27 in which the cross-sectional direction of the front side member 2 is substantially rectangular and the cross-section gradually increases in the longitudinal direction as cavities 26 and 27. 28 is on the diagonal of the rectangular cross section.
[0025]
A liquid injection nozzle 29 is attached to the lower mold 25. The nozzle 29 is supplied with high-pressure liquid from a high-pressure generator (not shown) via a liquid passage 30 formed in the lower die 25 and a high-pressure hose 34 connected to the liquid passage 30. The liquid injection part 21 of the preform 20 is formed in advance in a hollow shape so as to receive the nozzle 29, and a fitting hole 31 with which the nozzle 29 fits is formed in the second metal plate 7.
[0026]
The upper mold 24 and the lower mold 25 are formed with grooves 32, 33, respectively, for accommodating the shape of the liquid injection part 21 forming the hollow shape of the preform 20, and the grooves 32, 33, the mold cavities 26, 27, Between them are formed inclined surfaces 32a, 33a which are inclined so that the sectional area gradually increases from the concave grooves 32, 33 toward the cavities 26, 27, respectively. The concave grooves 32, 33 and the inclined surfaces 32a, 33a are formed substantially evenly with respect to the mating surface of the metal plates 6, 7, that is, the dividing surface 28 of the upper mold 24 and the lower mold 25. It is set so as to have substantially the same area (volume) across the surface 28. On the division surface 28, the mating surface of the reinforcing plates 8, 9 including the diagonal line of the rectangular front side member 2, the injection axis of the nozzle 29, and the center of the preliminary reinforcing member is set. That is, the centers of the reinforcing plates 8 and 9 and the center of the intermediate portion 23 are set at the same position on the division surface 28.
[0027]
As shown in FIG. 7, in a state where the preform 20 is clamped between the upper mold 24 and the lower mold 25, the high-pressure liquid generated by the high-pressure generator is passed through the high-pressure hose 34 and the liquid passage 30. The liquid is supplied to the nozzle 29 via the nozzle 29, and is injected into the inside of the liquid injection part 21 from the fitting hole 31 formed in the preform 20 by the nozzle 29. The high-pressure liquid does not leak out of the preform 20 because the peripheral portions 10 of the two metal plates 6 and 7 overlapped with each other are joined to each other over the entire circumference.
[0028]
Due to the high pressure of the liquid, the preform 20 gradually expands and deforms from a portion near the nozzle 29 toward the prereinforcement portion 22. As shown in FIGS. 2 and 3, the metal plates 6 and 7 and the reinforcing plates 8 and 9 are deformed into appropriate shapes by the hydroforming, for the following reasons. . In the deformation process by the hollow molding, first, the preliminary deformation portions 47 and 35 are deformed along the inner surfaces of the concave grooves 32 and 33. These preliminary deformation portions 47 and 35 are formed so that the nozzle side is formed in advance along the inner surfaces of the concave grooves 32 and 33 and are set up and down (similarly) to the dividing surface 28 so that the nozzles The bulge deforms uniformly and smoothly along the grooves 32 and 33 in the longitudinal direction and the direction perpendicular to the longitudinal direction so as to follow the shape of the side portion. In addition, since the cross-sectional areas are set to gradually increase at the inclined surface portions 32a and 33a, the metal plates 6 and 7 smoothly swell and deform into shapes along the inner surfaces of the cavities 26 and 27. .
[0029]
Therefore, at the stage when the preliminary reinforcing portion 22 starts to deform, the metal plates 6 and 7 around the intermediate portion 23 have already bulged and deformed along the wall surfaces of the cavities 26 and 27, and follow the shape of this portion. As described above, first, the portions of the metal plates 6 and 7 near the intermediate portion 23 of the preliminary reinforcing portion 22 appropriately swell and deform. In accordance with the deformation of the metal plates 6, 7, the reinforcing plates 8, 9 joined to the metal plates 6, 7 are deformed and bent. In this way, the length of the intermediate portion 23 in the longitudinal direction is set to be sufficiently long so that the deformation of the preliminary reinforcing portion 22 proceeds satisfactorily. In accordance with the deformation of the reinforcing plates 8, 9, four spaces extending in the longitudinal direction which are partitioned by the reinforcing plates 8, 9 are uniformly formed without their shapes being individually varied. The uniform hydraulic pressure P acts on the inner surfaces of the plates 6 and 7 so that the metal plates 6 and 7 have a final rectangular cross-sectional shape along the wall surfaces of the cavities 26 and 27, and the size of the cross-section in the longitudinal direction is reduced. It swells and deforms into a gradually changed shape. FIG. 9 shows a cross section of the mold after molding.
[0030]
As described above, the diagonal line of the hollow shell after the hydroforming is located on the dividing surface 28 of the upper mold 24 and the lower mold 25, and the flange-shaped metal plate 6, 7 is joined to each other along the dividing surface 28. In the process where the metal plates 6 and 7 gradually expand and deform due to the liquid, the flange-shaped side edges 10 are smoothly drawn into the cavities 26 and 27 because the metal plates 6 and 7 gradually expand and deform. And flows in. For this reason, the metal plates 6 and 7 can be smoothly expanded and deformed.
[0031]
After the deformation is completed, the pressure of the liquid is removed, the hollow molded body 36 is taken out from the upper mold 24 and the lower mold 25, and unnecessary portions at both ends in the longitudinal direction are cut off, so that the above-described reinforcing section is divided into a plurality of sections. It is possible to obtain the front side member 2 composed of the front part 15 and the non-reinforcement part 14 and having a gradually increasing cross-sectional area.
[0032]
According to the front side member 2, at the time of a frontal collision, first, the non-reinforcing portion 14 is quickly crushed, and then the reinforcing portion 15 partitioning the cross section by the reinforcing body is crushed. Since the reinforcing portions 15 have more ridges in the cross section due to the reinforcing plates 8 and 9 that partition the cross section, the reinforcing section 15 has high strength and high reaction force can be obtained. Further, in the front side member 2, since the cross-sectional shape of the substantially rectangular portion having the reinforcing body has an outer shape configured to increase gradually in the longitudinal direction, the reaction force increases as the crushing progresses. In addition, since the crushed portions are less likely to overlap, the remaining crushing is reduced and the effective crushing stroke is increased, so that the collision energy absorption efficiency as a whole can be effectively increased while suppressing the initial reaction force at the time of the collision. Further, since the flanges protrude diagonally, the collapse mode is stabilized. In addition, since the flat plate portions 8a and 8b intersect so as to be orthogonal to each other, high strength can be obtained even for a load in a direction orthogonal to the longitudinal direction.
[0033]
In the first embodiment, two reinforcing plates 8 and 9 are used, but the present invention is not limited to this. For example, as shown in FIG. 10, a single reinforcing plate 37 may be configured to partition the inside of the hollow shell formed of the metal plates 6 and 7 into two spaces. Similarly, as shown in FIG. 11, two reinforcing plates 38, 39 for partitioning the inside of the hollow shell composed of the metal plates 6, 7 into three spaces may be formed. The hollow shell having the reinforcing member shown in FIGS. 10 and 11 can be formed by performing hydraulic forming using the preformed members 40 and 41 having the structures shown in FIGS. 12 and 13, respectively. Further, these cross-sectional shapes can be arbitrarily changed in the middle of the longitudinal direction, and a combination can be freely selected according to required energy absorption performance.
[0034]
In the above description, the front side member 2 has been described. However, it is needless to say that the present invention can also be applied to a rear side member (not shown) which is installed at the rear of the vehicle and absorbs energy from a collision from the rear of the vehicle.
[0035]
[Embodiment 2]
Next, a second embodiment of the present invention will be described. In this embodiment, the present invention is applied to a crash box 3 extending further forward from a front end of a front side member 2 of an automobile body 1 shown in FIG. In the description of this embodiment, a description of the same configuration as that of the first embodiment, and the operation and effect of the configuration will be appropriately omitted.
[0036]
In FIG. 1, the crash boxes 3 are disposed substantially symmetrically at the front end of the front side member 2, and the left and right crash boxes 3 are further connected to bumpers 4 located in front of them. Energy at the time of a frontal collision is first transmitted to the bumper 4, which is transmitted to the left and right crash boxes 3, and further transmitted to the front side member 2.
[0037]
FIG. 14 is a perspective view of the crash box 3. The crash box 3 has a hollow outer shell composed of two metal plates 51 and 52. The hollow shell has a substantially rectangular cross-section and has a closed cross-section structure that extends while gradually increasing the cross-section in the longitudinal direction. Inside the hollow outer body, there is provided a reinforcing portion 56 having a substantially cross-shaped cross section and having a pair of reinforcing plates 53 and 54 crossing each other. The reinforcing plates 53 and 54 partition the interior of the hollow shell into four spaces extending in the longitudinal direction and gradually increasing in cross-sectional space. Both side edges 55 of the hollow shell have a flange shape protruding from the rectangular portion of the hollow shell, and project in a direction diagonally extending from the rectangular portion. 51 and 52 are joined to each other.
[0038]
The crush box 3 is manufactured through a cutting process or the like from a hollow molded body obtained by hydraulically molding a preformed body 57 described later. FIG. 15 is a perspective view of the preform 57. The preform 57 includes two metal plates 51 and 52 serving as hollow shells and two reinforcing plates 53 and 54 serving as reinforcing portions 56. The cross-sectional shape is the shape shown in FIG. Is the same as However, in this embodiment, as shown in FIG. 15, the preformed body 57 gradually increases in width from the liquid injection part 58 to the non-reinforced part 59 and the reinforcing part 56 on the side orthogonal to the longitudinal direction. However, the preform 57 gradually decreases from the center to the rear, that is, is a preformed body 57 having a symmetrical shape in the front and rear at the center. As described later, the preform 57 has a two-cavity shape in which the left and right crash boxes are connected at the center. ing.
[0039]
The method of swelling and deforming the preform 57 by hydroforming is the same as in the first embodiment. However, in the present embodiment, as shown in FIG. 16, the upper die and the lower die in which cavities corresponding to the outer shape of the crush box 3 are formed, a right side crush box 61 having a gradually increasing cross section, and a The feature is that a gradually decreasing left side crush box 62 has an outer shape combined by a central change portion 63 and a cavity of a mold is formed.
[0040]
When liquid is injected from the liquid injection part 58 of the preform 57 into each space part partitioned by the two metal plates 51, 52 and the reinforcing plates 53, 54, the vicinity of the liquid injection part 58 is the same as in the first embodiment. Therefore, the liquid pressure can be uniformly applied to each space partitioned by the reinforcing plate, and the hollow molded body can be obtained by expanding and deforming the preformed body 57. When the unnecessary portions before and after the hollow molded body are cut, an intermediate molded body 60 in which the right-side crash box 61 and the left-side crash box 62 are connected by the center changing portion 63 as shown in FIG. 16 is obtained. Is further divided into two at the center, so that two parts for the left and right sides of the crash box 3 can be obtained at the same time.
[0041]
The crush box 3 shown in FIG. 14 is manufactured from the hollow molded body obtained by this manufacturing method. According to the crush box 3, the reinforcing portion 56 has a higher ridge line in the cross section due to the reinforcing plates 53 and 54 that partition the cross section. Further, since the cross-sectional shape of the substantially rectangular portion having the reinforcing plate has an outer shape configured to increase gradually in the longitudinal direction, the reaction force increases as the crushing progresses, and the crushed portion. Are less likely to overlap, so less crushing remains and more effective crushing strokes. Therefore, the collision energy absorption efficiency can be effectively improved as a whole. Also, by forming a mold cavity with an outer shape that connects the right side crash box 61 with a gradually increasing cross section and the left side crash box 62 with a gradually decreasing cross section at the center, the left and right parts can be molded simultaneously in one molding. As a result, the productivity and the material yield are improved, and the molded body has a smooth shape that is easily swelled and deformed.
[0042]
It is needless to say that the number and structure of the reinforcing plates as shown in FIGS. 10 and 11 in the first embodiment can be arbitrarily selected and applied to the crash box 3 according to the required performance.
[0043]
[Embodiment 3]
In this embodiment, the present invention is applied to a hood ledge 5 located above a side member 2 of an automobile body 1 shown in FIG.
[0044]
FIG. 17 is a perspective view of the hood ledge 5, and FIG. 18 is a view taken in the direction of arrow Q in FIG. The shape of the hood ledge 5 shown in FIG. 17 is a hollow shell made of two metal plates 71 and 72. The hollow shell has a substantially rectangular cross-section, and has a closed cross-sectional structure extending while gradually increasing the cross-sectional area in the longitudinal direction. The expanding direction is, in the vehicle assembled state of FIG. Has no change and has a shape that gradually expands outside and above the vehicle. Inside the hollow shell, reinforcing plates 73 and 74 having a pair of flat plates 73a and 73b crossing each other and having a substantially cross-sectional shape are provided. The reinforcing plates 73 and 74 partition the interior of the hollow shell into four spaces extending in the longitudinal direction and gradually increasing in the size of the cross-sectional space. Both side edges 75 of the hollow shell have a flange shape protruding from the rectangular portion of the hollow shell, and project in a direction diagonally extending from the rectangular portion. 71 and 72 are joined to each other.
[0045]
The hood ledge 5 is manufactured from a hollow molded body obtained by hydroforming the preformed body 77 shown in FIG. FIG. 19 is a perspective view of the preform 77. The preform 77 is composed of two metal plates 71 and 72 serving as hollow outer shells and two reinforcing plates 73 and 74 serving as reinforcing portions 76, and has a cross-sectional shape shown in FIG. The same is true. However, in the present embodiment, as shown in FIG. 19, the preformed body 77 is formed such that the width on the side orthogonal to the longitudinal direction is sequentially changed from the liquid injection part 78 to the non-reinforced part 79 and the reinforcing part 76 in only one direction. This is a preform 77 having an asymmetric shape that gradually increases toward the front side in FIG.
[0046]
The method of expanding and deforming the preformed body 77 by hydraulic forming is the same as that of the first embodiment, but as described above, the outer shape of the hood ledge 5 is substantially rectangular in cross section, and the cross section is gradually enlarged in the longitudinal direction. It has a closed cross-sectional structure extending while extending. The direction of the expansion is unchanged in the vehicle inward and downward directions of the vehicle in the assembled state of the vehicle, and gradually expands in the outward and upward directions of the vehicle. Therefore, as shown in FIG. Correspondingly, an upper die 80 and a lower die 81 having cavities 82 and 83 whose cross sections gradually increase in a specific direction are used.
[0047]
When liquid is injected from the liquid injection part 78 of the preform 77 into each space part partitioned by the two metal plates 71 and 72 and the reinforcing plates 73 and 74, the vicinity of the liquid injection part 78 is the case of the first embodiment. Therefore, the liquid pressure can be uniformly applied to each space partitioned by the reinforcing plate, and a hollow molded body can be obtained by expanding and deforming the preformed body 77.
[0048]
The hood ledge 5 shown in FIG. 17 is manufactured from the hollow molded body obtained by this manufacturing method. In the hood ledge 5, similarly to the side members and the crash box described above, the high-strength reinforcing portion 76 can obtain a high reaction force. Furthermore, since the cross-sectional shape of the substantially rectangular portion having the reinforcing plates 73 and 74 has an outer shape that gradually increases in a specific direction in the longitudinal direction, the reaction force against a load acting in the axial direction also gradually increases. In addition, since the remaining crushing is reduced and the effective crushing stroke is increased, the collision energy absorption efficiency can be effectively improved as a whole. At the same time, since the hood ledge 5 can be prevented from expanding its cross section in the vehicle inside direction and in the vehicle downward direction when the vehicle is assembled, interference with the engine, tires, suspension, and the like can be avoided, and the layout of the vehicle components is facilitated.
[0049]
In the hood ledge 5, the number and structure of the reinforcing plates as shown in FIGS. 10 and 11 can be arbitrarily selected and applied in the first embodiment of the side member. Conversely, a shape having a reinforcing portion and having a cross section expanding only in a specific direction as shown in the present embodiment may be applied to the side member or the crash box described above. In this case, at the time of an oblique collision or the like, it becomes possible to manufacture a side member or a crash box that has a high strength in a required specific direction and a high reaction force.
[0050]
[Embodiment 4]
In this embodiment, the present invention is applied to a bumper 4 extending in the left-right direction at a front end portion or a rear end portion (not shown) of the vehicle body 1 shown in FIG.
[0051]
FIG. 21 is a perspective view of the bumper 4, and FIG. 22 is a view as viewed from the direction R in FIG. In the bumper 4, the inside of the metal plates 91 and 92 forming the hollow outer body having a substantially rectangular cross section is partitioned by a plurality of reinforcing plates 93 and 94, and the crossing of the reinforcing plates 93 and 94 is performed. The position 96 has a cross-sectional shape offset from the center position of the hollow shell. The cross-sectional shape of the bumper 4 has a shape that expands toward the vehicle front part 98 and the vehicle upper part 97 as it goes to the center in the left-right direction of the vehicle in the assembled state of the vehicle shown in FIG.
[0052]
FIG. 23 shows a cross-sectional view of the preform 95. This is a preform 95 substantially similar to that of the third embodiment, except that the width of the first reinforcing plate 93 and the second reinforcing plate 94 in the cross-sectional direction is different, and the intersection position 96 joined to each other is different. The preform 95 is offset from the center of the two metal plates 91 and 92. The subsequent manufacturing method is the same as in the third embodiment.
[0053]
In the present embodiment, after the hydroforming, the flange 99 on the vehicle front side on the diagonal line 89 of the rectangular portion is bent so as to be flush with the front wall 88 of the vehicle.
[0054]
The bumper 4 obtained by the present invention and having a shape whose cross section is enlarged toward the center of the left and right of the vehicle can be used when a collision input acts on the center of the bumper or on one side of the bumper such as a pole collision or an offset collision. Bending between the boxes 3 can be prevented, and a load can be transmitted well to the crash box 3 and the side members 2 connected to the bumper 4. In addition, the intersection position of the plurality of reinforcing plates 93 and 94 can be arbitrarily set according to the height position of the bumper 4 and the height positions of the left and right crash boxes 3 and the side members 2. , The load from the bumper 4 can be appropriately set so as to be transmitted to the side member 2 satisfactorily, and the degree of freedom in structural design is high. Further, as in the case of the first embodiment, the number and structure of the reinforcing plates as shown in FIGS. 10 and 11 can be appropriately applied to the reinforcing body of the bumper 4.
[0055]
As described above, the present invention has been described based on the specific embodiments 1 to 4. However, the present invention is not limited to the above embodiments, and may be modified without departing from the technical spirit thereof. Various modifications and changes are possible. For example, the material, thickness, and the like of the metal plate and the reinforcing plate to be overlapped are not limited to the illustrated form, and can be arbitrarily set according to required performance.
[0056]
The invention described in each claim has the following effects.
[0057]
According to the preform in the hydroforming according to claim 1, the preform is hydroformed so that the hollow shell is formed by the two metal plates overlapped with each other, and The outer shell can simultaneously form a reinforcing member that partitions a hollow cross section whose cross-sectional area gradually changes in the longitudinal direction, and is easy to manufacture. In addition, since the pre-reinforcing body that deforms into the reinforcing body can be joined to the metal plate before deformation in advance, the joining operation is easy, and the degree of freedom in the layout and shape of the reinforcing body is high. .
[0058]
According to the preform in the hydroforming according to claim 2, the inside of the hollow outer body after the molding is divided into four spaces extending in the longitudinal direction by the flat plate portion, and is excellent in strength and rigidity. It becomes.
[0059]
According to the preform in the hydroforming according to the third aspect, the hollow molded body formed from the preform has a gradually changing cross-sectional area in the longitudinal direction and connects the opposing surfaces of the hollow shell to each other. The reinforcing body has excellent strength and rigidity, and can effectively absorb and disperse an impact load. In addition, the reinforcing member can be arranged only in a part of the longitudinal direction, and the degree of freedom of layout is high.
[0060]
According to the preform in the hydroforming according to the fourth aspect, the reinforcing property of the product obtained from the preform becomes excellent.
[0061]
According to the preform in the hydroforming according to the fifth aspect, the load can be dispersed between the reinforcing plates in the obtained product, and the reinforcing performance is excellent.
[0062]
According to the hydraulic molding method of the hollow molded body according to the sixth aspect, since the intermediate portion where the preliminary reinforcing member is not provided is provided between the liquid injection portion and the preliminary reinforcing portion, the liquid injection portion is provided with the intermediate portion. When a high-pressure liquid is injected, first, the intermediate portion gradually deforms, and the preliminary reinforcing portion deforms so as to follow this. Therefore, the shape of the plurality of spaces partitioned by the reinforcing member is appropriately formed without variation, and the metal plate can be appropriately expanded and deformed by the uniform hydraulic pressure acting on these spaces. In this way, it is possible to simultaneously form a reinforcing body that divides a cross section into a plurality of pieces at the time of hollow molding in which two metal plates are bulged and deformed into a hollow shape whose cross section gradually changes in the longitudinal direction. In addition, a hollow molded body having excellent energy absorption performance can be easily manufactured.
[0063]
According to the method of hydraulically molding a hollow molded body according to claim 7, as the metal plate gradually expands and deforms due to the hydraulic molding, the flange-shaped side edges are smoothly inserted into the cavity of the mold. The metal plate can be guided and swelling deformation of the metal plate can be favorably performed. Further, since the flange protrudes in the diagonal direction, it becomes easy to obtain a member having excellent energy absorption efficiency.
[0064]
According to the hydraulic forming method of the hollow molded body according to the eighth aspect, for example, the first preliminary reinforcing member made of one reinforcing plate and the second preliminary reinforcing member made of a plurality of reinforcing plates are combined. The two preforms can be provided at different positions in the longitudinal direction, and a design according to performance can be made.
[0065]
According to the method of hydraulically molding a hollow molded body according to the ninth aspect, the interior of the hollow molded body after the hydraulic molding is divided into upper, lower, left, and right by two reinforcing plates, so that either the up, down, left, or right direction. In addition, a hollow molded body having high strength in the axial direction can be obtained.
[0066]
According to the method for hydraulically molding a hollow molded body according to the tenth aspect, it is possible to obtain a hollow molded body whose interior is divided into four evenly by the two reinforcing plates.
[0067]
According to the hydraulic molding method for a hollow molded body according to claim 11, even when the cross section of the hollow molded body is a long shape, for example, the cross section of the hollow molded body is evenly formed by the two reinforcing plates. Or it can be partitioned at any position.
[0068]
According to the method of hydraulically molding a hollow molded body according to the twelfth aspect, a hollow molded body having a cross section that changes in the longitudinal direction and having a reinforcing plate inside can be easily obtained.
[0069]
According to the method of hydraulically molding a hollow molded body according to the thirteenth aspect, for example, left and right parts and a plurality of parts can be obtained at the same time, and the productivity and economical efficiency related to production are improved.
[0070]
According to the hydraulic molding method of the hollow molded body according to the fourteenth aspect, since the ridge lines are increased in the cross section by the reinforcing material, high strength and high reaction force can be obtained. In addition, it is possible to form an integral structural member in which the cross-sectional area of the hollow portion having the reinforcing material is gradually and uniformly enlarged in the longitudinal direction, and the uncrushed portion is reduced when the shaft is compressed, so that the collision energy absorption efficiency is effectively increased. Can be. Further, the reinforcing member can be easily arranged at an arbitrary position in the longitudinal direction of the hollow molded body, and the degree of freedom of the shape and the layout increases in designing the energy absorbing performance.
[0071]
According to the hydraulic molding method of the hollow molded body according to the fifteenth aspect, the strength becomes high in a specific direction required at the time of oblique collision or the like, and a high reaction force is obtained.
[0072]
According to the hydraulic molding of the hollow molded body according to the sixteenth aspect, the strength becomes high in a required specific direction and a high reaction force is obtained. In designing the energy absorption performance, the degree of freedom of the shape and layout is increased.
[0073]
According to the hydraulic molding of the hollow molded body according to claim 17, when a collision input acts on the center of the bumper or on one side of the bumper, it is possible to prevent bending between the left and right crash boxes, and to the vehicle body. The load can be transmitted well.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a skeleton of a front portion of an automobile body.
FIG. 2 is a perspective view of a front side member.
FIG. 3 is a view from arrow P in FIG. 2;
FIG. 4 is a view showing a preform formed by two metal plates and two reinforcing plates.
FIG. 5 is a sectional view of the preform taken along line XX of FIG. 4;
6 is a longitudinal sectional view of the preform taken along the line YY in FIG. 4;
FIG. 7 is a cross-sectional view of the mold and the preformed body according to the first embodiment before hydraulic forming.
FIG. 8 is a sectional view taken along the line ZZ in FIG. 7;
FIG. 9 is a cross-sectional view of the mold and the preformed body according to Embodiment 1 after hydraulic forming.
FIG. 10 is a sectional view showing another example of the first embodiment.
FIG. 11 is a sectional view showing still another example of the first embodiment.
FIG. 12 is a cross-sectional view showing another example of a preform for the first embodiment.
FIG. 13 is a cross-sectional view showing still another example of a preform according to the first embodiment.
FIG. 14 is a perspective view of a crash box according to the second embodiment.
FIG. 15 is a perspective view of a preform according to the second embodiment.
FIG. 16 is a perspective view of an intermediate molded body according to the second embodiment.
FIG. 17 is a perspective view of a hood ledge according to the third embodiment.
18 is a view as seen from the direction of arrow Q in FIG. 17;
FIG. 19 is a perspective view of a preform according to a third embodiment.
FIG. 20 is a cross-sectional view of the mold and the preformed body according to Embodiment 3 after hydraulic forming.
FIG. 21 is a perspective view of a bumper according to a fourth embodiment.
FIG. 22 is a view as viewed from the direction R in FIG. 21;
FIG. 23 is a sectional view of a preform according to a fourth embodiment.
[Explanation of symbols]
1: Front end of car body
2. Front side member
3. Crash box
4. Bumper
5. Food Ledge
6, 7, 51, 52, 71, 72, 91, 92 ... metal plate
8, 9, 37, 38, 39, 53, 54, 73, 74, 93, 94 ... reinforcing plate
10, 12, 13, 55, 75 ... Both side edges
11, 96 ... bending part
14, 59, 79 ... non-reinforced part
15, 56, 76 ... reinforcing part
20, 40, 41, 57, 77, 95 ... preform
21, 58, 78: liquid injection section
22 Preliminary reinforcement
23, 59, 79 ... middle part
24, 25, 80, 81: Vertical type
26, 27, 82, 83 ... cavity
28 ... Division surface
29 ... Nozzle
30 ... liquid passage
31 ... mating hole
32, 33 ... groove
32a, 33a ... inclined surface
34… High pressure hose
35, 47 ... preliminary deformation part
36 ... Hollow molded body
60: Intermediate molded body
61 ... Crash box for right side
62… Crash box for left side
63: Central change part
73a, 73b ... flat plate part
88: Vehicle front side wall,
96 ... intersection position,
97 ... vehicle upper part,
98 ... vehicle front part,
99 ... Flange.

Claims

A hollow having at least two metal plates superimposed on each other, the two side edges along the longitudinal direction of the two metal plates being joined, and the two metal plates extending in the longitudinal direction by hydraulic forming; A preform in hydroforming that is swelled and deformed into an outer shell,
Between the two metal plates, a pre-reinforcement body joined to the inner surface of each of the two metal plates is interposed in advance, and the width of the pre-reinforcement in the cross-sectional direction extends in the longitudinal direction of the metal plate. The preliminary reinforcing body is formed into a reinforcing body that extends in the longitudinal direction of the hollow shell and partitions the inside into a plurality of spaces whose sectional area gradually changes by the hydraulic forming. A preform in hydroforming, characterized by being deformed.

2. The hydroforming according to claim 1, wherein the reinforcing member includes a pair of flat plate portions that intersect each other, and each flat plate portion is bridged on inner surfaces of the hollow outer body facing each other. 3. Preformed body.

A hollow having at least two metal plates superimposed on each other, the two side edges along the longitudinal direction of the two metal plates being joined, and the two metal plates extending in the longitudinal direction by hydraulic forming; A preform in hydroforming that is swelled and deformed into an outer shell,
A pre-reinforcing portion between the two metal plates, a pre-reinforcing member disposed on the inner surface of each of the two metal plates; and a liquid injection for injecting a liquid during the hydroforming. And a middle portion where the preliminary reinforcing member is located between the preliminary reinforcing portion and the liquid injection portion in the longitudinal direction of the metal plate and is not disposed,
The width of the pre-reinforcement in the cross-sectional direction gradually changes in the longitudinal direction of the metal plate.

The pre-reinforcement is constituted by a pair of flat plates intersecting each other at an intersecting position extending in the longitudinal direction of the metal plate, and both side edges of each flat plate are respectively joined to opposing surfaces of the hollow shell. The preform according to claim 3, wherein the preform is formed by hydroforming.

The preform according to claim 4, wherein the preform is bent at the intersection and is joined to each other.

A pre-reinforcing portion in which pre-reinforcing members joined to respective inner surfaces of the first metal plate and the second metal plate are disposed between the first metal plate and the second metal plate stacked on each other; A liquid injection portion into which a liquid is injected at the time of hydroforming; and the preliminary reinforcing member positioned between the preliminary reinforcement portion and the liquid injection portion in the longitudinal direction of the first metal plate and the second metal plate. Is provided, an intermediate portion is not provided, and both side edges along the longitudinal direction of the first metal plate and the second metal plate are joined to each other to form a preform,
Sandwiching the preform between an upper mold and a lower mold in which a cavity is formed,
Inject liquid into the liquid injection part of the preform,
A method of hydraulically forming a hollow molded body, comprising bulging the hollow molded body.

The cross-sectional shape orthogonal to the longitudinal direction of the hollow molded body is rectangular, and a division surface between the upper mold and the lower mold is arranged on a diagonal line of the rectangle. Hydraulic molding method of the hollow molded article.

The method according to claim 6, wherein the preliminary reinforcing member is configured by one or more reinforcing plates.

The preliminary reinforcing member includes two reinforcing plates, and the two reinforcing plates are joined to each other at intersections along the longitudinal direction of the first metal plate and the second metal plate. The hydraulic molding method for a hollow molded article according to claim 6 or 7, wherein:

The method according to claim 9, wherein the crossing position is located substantially at the center of the hollow molded body after the hydraulic molding.

The method of claim 9, wherein the two reinforcing plates are joined to each other at a position offset from a center of the hollow molded body in a cross-sectional width direction.

7. The pre-reinforcement according to claim 6, wherein a width in a cross-sectional direction of the pre-reinforcement gradually increases up to a central portion in a longitudinal direction of the first metal plate and the second metal plate, and thereafter gradually decreases. Hydraulic molding method for hollow molded articles.

The method according to claim 12, further comprising a step of obtaining two hollow molded bodies by cutting the hollow molded body from substantially the center in a cross-sectional direction thereof after the preform is hydraulically molded. Hydraulic molding method for hollow molded articles.

The hollow molded body is a vehicle body structural member, and is a side member or a crash box configured so that a substantially rectangular cross-sectional shape provided with the reinforcing body gradually increases in a longitudinal direction thereof. The hydraulic molding method for a hollow molded article according to any one of claims 6 to 13.

The hollow molded body is a vehicle body structural member, and is a side member or a crash box configured so that a substantially rectangular cross-sectional shape provided with the reinforcing body gradually increases only in a specific direction in a longitudinal direction thereof. The method of hydraulically molding a hollow molded article according to any one of claims 6 to 13, wherein:

The hollow molded body is a body structural member of an automobile, and is a hood ledge configured so that a substantially rectangular cross-sectional shape provided with the reinforcing body gradually increases only in a specific direction in a longitudinal direction thereof. A method for hydraulically molding a hollow molded article according to any one of claims 6 to 13.

The hollow molded body is a vehicle body structural member of an automobile, and is a bumper configured such that a substantially rectangular cross-sectional shape provided with the reinforcing body gradually increases and decreases in a specific direction in a longitudinal direction thereof. A method for hydraulically molding a hollow molded article according to any one of claims 6 to 13.