JP3931419B2

JP3931419B2 - Body bumper structure

Info

Publication number: JP3931419B2
Application number: JP05423498A
Authority: JP
Inventors: 真幸吉光; 大希男多田
Original assignee: Isuzu Motors Ltd
Current assignee: Isuzu Motors Ltd
Priority date: 1998-02-20
Filing date: 1998-02-20
Publication date: 2007-06-13
Anticipated expiration: 2018-02-20
Also published as: JPH11235958A

Description

【０００１】
【発明の属する技術分野】
本発明は、車体側に取り付けられるバンパ構造に係り、特に、外力作用時において衝撃エネルギーを吸収するに好適な車体用バンパ構造に関する。
【０００２】
【従来の技術】
自動車の前後にはバンパが取り付けられ自動車を保護している。例えば、図９は自動車の後方に取り付けられる従来のバンパ構造を示すものである。自動車の後方にはリヤボディパネル１０が設けられ、リヤバンパ１２はその下方の後方に配置され、外力がリヤボディパネル１０に直接作用するのを防止している。従来のリヤバンパ１２は図示のようにシャシフレーム１３側に固定されるものが多く、リヤボディパネル１０側には固定されない。すなわち、シャシフレーム１３に基端側を固定されるバックバー２３の後端側にはリインフォース２４が固定され、リヤバンパ１２はこのリインフォース２４に固定される。
【０００３】
【発明が解決しようとする課題】
図９に示したリヤバンパ１２に外力が作用すると、その衝撃力はリヤバンパ１２を介してリインフォース２４及びシャシフレーム１３等に作用する。これ等は比較的高剛性のため変形量は少なく、リヤボディパネル１０の損傷は生じない。しかしながら、衝撃エネルギーの吸収度合は少なく、大きな衝撃力が自動車に作用する。一方、近年の傾向としてバンパを直接車体側に固定するものが採用される。すなわち、図９におけるリヤボディパネル１０側に直接リヤバンパ１２の基端側を固定するものが採用される。従って、リヤバンパ１２側に衝撃エネルギーを吸収する手段が設けられていないとリヤボディパネル１０側に外力が直接作用し、これを変形させるという問題点がある。
【０００４】
衝撃吸収部材をバンパ内及びバンパまわりに設けた公知技術としては各種のものが挙げられる。例えば、実開昭５９−１１０７５４号公報，実開昭５９−１５１７５６号公報，実開昭６１−１９３８４６号公報等がある。実開昭５９−１１０７５４号公報の「自動車用バンパ構造」は、表皮材と強度部材とを組み合わせて形成される自動車用バンパの前記強度部材に、衝突エネルギー吸収部材を固設し、その先端側を前記表皮材に近接して配置し、外力作用時に衝突エネルギー吸収部材を表皮材に当接せしめて衝突エネルギーを吸収するものである。また、実開昭５９−１５１７５６号公報の「自動車用バンパ構造」は、バンパを車体部材に固定するためのステーに衝突エネルギーを吸収し得る変形部を設け、外力作用時には前記変形部の変形により衝突エネルギーを吸収するものである。また、実開昭６１−１９３８４６号公報の「自動車のバンパー」は、バンパー本体の内側に中空に成形したインナー部品を配置し、このインナー部品に蛇腹部を設け、この蛇腹部を前記バンパ本体及び／又は車のボディ側に固定したものである。
【０００５】
前記の公知技術はいずれも外力作用時において衝突エネルギーを有効に吸収し、車体側の変形を防止する効果を有するものである。しかしながら、これ等はすべてバンパ側に装着されるものであり、バンパと離隔して配置されるものではない。また、その衝突吸収箇所もバンパの長手方向の全長にわたって形成されるものではなく、部分的に配設されるものである。そのためバンパに作用する外力の形態によっては衝突エネルギーの吸収が不十分となる恐れが多い。また、前記のようにバンパと一体的構造のため、バンパ自体がコスト高となり、組み付けた多くの時間を必要とする。また、これ等の公知技術では、極めて大きな外力が作用した場合の配慮が不十分である。
【０００６】
本発明は、以上の事情に鑑みて創案されたものであり、車体側に保持されるバンパ構造であって、各種形態の外力の作用時において衝撃エネルギーを十分に吸収することができ、更に大きな外力作用時においても車体側の変形を低減すべく機能し、かつ比較的構造簡単で安価に実施でき、組み付けが比較的容易に行われる車体用バンパ構造を提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明は、以上の目的を達成するために、車体側に保持されると共に適宜間隔を介してシャシフレームの端部と相対向して配置され、外力作用時における衝撃エネルギーを吸収すべく形成されるバンパ構造であって、前記車体側とバンパの内面との間に前記バンパの全長とほぼ同一の長さを有し、前記外力の作用方向に沿って変形する別体の衝撃吸収部材を介在させ、該衝撃吸収部材は、前記外力の作用時において少なくとも前記シャシフレームの端部よりも先に前記バンパに当接すべく配置され、その横断面が波形状に形成され、外力作用時に座屈の基点となる衝撃吸収孔が設けられることを特徴とする。
【０００８】
バンパは車体側に保持され、これと別体の衝撃吸収部材を前記車体側とバンパの内面との間に介設させる。また、バンパはシャシフレームの端部と相対向して配置され、外力が作用しない場合は、バンパは衝撃吸収部材及びシャシフレームの端部等と間隔を有する位置に配置されるが、衝撃吸収部材の方がバンパに近接して配置される。外力作用時にバンパはまず衝撃吸収部材に当り、衝撃エネルギーの吸収が行われる。更に、大きな外力が作用すると、衝撃吸収部材が更に変形すると共にバンパはシャシフレームの端部に当り、この変形により衝撃エネルギーの吸収を行う。以上により、外力作用時において車体側の変形が防止される。なお、車体修理時には、バンパ及び別体の衝撃吸収部材を交換すればよく、修理費は比較的安くすむ。また、衝撃吸収部材は別体のため、組み付けや交換が比較的簡単に行われ、作業性の向上が図れる。
【０００９】
【発明の実施の形態】
以下、本発明の車体用バンパ構造の実施の形態を図面を参照して詳述する。本例は車体のリヤボディパネル側に装着されるリヤバンパについて説明するが、勿論、これに限定するものではない。図１及び図３に示すように、車体の最後部の開口部１５を開閉するリヤドアパネル１６の下方側にはリヤボディパネル１０が配置される。また、その下方にはシャシフレーム１３が配置され、シャシフレーム１３の端部にはクロスメンバ１４が左右のシャシフレーム１３の端部間に架設されて配置される。また、前記開口部１５を形成するリヤエンドパネル１７にはテールランプ１８等が装着される。
【００１０】
リヤバンパ１２は図１に示すような横断面形状を有する部材からなり、その基端側のフランジ１９はリヤボディパネル１０にボルト２０等により固定される。すなわち、リヤバンパ１２はリヤボディパネル１０に片持ち状態で保持される。一方、衝撃吸収部材である波形状部材１はリヤボディパネル１０とリヤバンパ１２の内面との間のシャシフレーム１３の上方側に配置され、後に詳述するがブラケット３によりリヤボディパネル１０に連結される。なお、図２に示すように、波形状部材１には衝撃吸収孔２５が開口形成される。衝突時等において波形状部材１はこの衝撃吸収孔２５を基点として座屈する。
【００１１】
図２は本例における波形状部材１の詳細構造を示す。波形状部材１はリヤバンパ１２の全長とほぼ等しい全長の細長い板材からなり、横断面形状としては複数個（図示では３個）の波形２を形成するものからなる。材質，板厚等については特に限定するものではないが、自動車に作用する衝撃力を十分に吸収し得る機能を有するものであればよい。ブラケット３は、本例では波形状部材１の両端側に連結されるものからなり、図１に示すように、波形状部材１の下面に当接する当接部４と、当接部４と直交しリヤボディパネル１０側に固定されるフランジ部５とを有するものからなる。ブラケット３には、取り付け孔６が本例では２箇所形成され、これと見合う波形状部材１の位置にも取り付け孔７が２箇所形成される。なお、ブラケット３と波形状部材１との固定はボルト８，ナット９により行われるが、ボルト８の直径に対し波形状部材１の取り付け孔７の内径は大径に形成され、その径差分だけ波形状部材１は移動可能になる。また、フランジ部５はリヤボディパネル１０にボルト１１等により固定される。従って、波形状部材１はブラケット３を介し、リヤボディパネル１０側に片持ち支持される。また、この状態で波形状部材１のリヤバンパ１２側の端部とリヤバンパ１２の内面の間には間隔ａが形成される。
【００１２】
前記したように、シャシフレーム１３の後端部にはクロスメンバ１４が固定され、クロスメンバ１４はリヤバンパ１２の内面と相対向して配置される。なお、クロスメンバ１４とリヤバンパ１２の内面との間の間隔ｂは波形状部材１の端部とリヤバンパ１２の内面との間の間隔ａよりも大きい。
【００１３】
次に、本例におけるリヤバンパ１２に外力が作用した場合の衝撃エネルギーの吸収状態を図４乃至図５の模式図により説明する。リヤバンパ１２に外力Ｆが作用すると、リヤバンパ１２自体が変形し、前記間隔ａがなくなり、リヤバンパ１２の内面が波形状部材１の端部に当る。更に、リヤバンパ１２が変形すると波形状部材１は衝撃吸収孔２５を基点として座屈が始まり、次第に波形２がつぶれ、全体が縮んで外力Ｆによる衝撃エネルギーを吸収する。この場合、波形状部材１はブラケット３により支持されているが、ブラケット３への取り付け孔７がボルト８の直径より大きいため、外力Ｆの作用によりまず、波形状部材１のみが縮み方向に移動し、次に、ブラケット３に外力が作用する。但し、後に説明するようにブラケット３は波形状部材１に較べて高剛性のため、ブラケット３と連結されている波形状部材１の部位の変形量は他の部分に較べて少ない。以上のように、波形状部材１は部分的に変形量は異なるが、外力Ｆによる衝撃エネルギーをその全長にわたる変形により吸収する。
【００１４】
外力Ｆよりも大きな外力Ｆ₁が作用すると、リヤバンパ１２の変形が更に進み、波形状部材１の変形も大きくなる。よって、リヤバンパ１２の内面がクロスメンバ１４の端面に当り、更に、クロスメンバ１４を変形させる。この状態では外力Ｆ₁による衝撃エネルギーは波形状部材１の変形とクロスメンバ１４の変形によって吸収される。しかしながら、クロスメンバ１４自体は比較的高剛性のため、その変形量は少なく、リヤボディパネル１０側の変形をくい止めることができる。以上により、外力による衝撃エネルギーの吸収と、リヤボディパネル１０側の変形防止との両効果を上げることができる。また、前記のように、本例の場合は、車両の横幅に近い全長を有する波形状部材１により衝撃エネルギーを吸収するため、従来技術に較べて衝撃エネルギーの吸収率を大幅に向上させることができる。また、波形状部材１はリヤバンパ１２とは別体のもので、車両の種類に応じて適宜のものを設定することができる。また、波形２の形状も任意に形成できる。更に、外力により変形した波形状部材１の交換も容易であり、新車の場合における取り付け作業もリヤバンパ１２の取り付けとは別に行われるため容易である。
【００１５】
次に、図６乃至図８により、リヤバンパ１２側に衝突する衝突物の種類に対応する波形状部材１の長手方向の波形状態を模式的に示す。図６は外力の作用前における波形状部材１及びこれを支持するブラケット３を模式的に示したものである。まず、図７に示すように、衝突物がポール２１の場合を説明する。ポール２１がリヤバンパ１２の中央に当接すると、波形状部材１の中央部が大きく変形し、それに伴って中央部以外の部分が変形する。以上の変形により衝撃エネルギーの吸収が行われる。この場合、ブラケット３側への外力の作用が比較的小さいためブラケット３側の変形は少ない。
【００１６】
次に、図８に示すように、リヤバンパ１２側に平板状衝突物２２が作用するとリヤバンパ１２及び波形状部材１の全体が変形する。この場合でも波形状部材１はその中央部が最も変形し易いが、その変形量は図７に示したポール２１が作用した場合よりも小さく、波形状部材１は全体として変形し、衝撃エネルギーを吸収する。更に、平板状衝突物２２による外力が大きい場合は、図８に示すようにブラケット３側も寸法δの分だけ移動し、衝撃エネルギーの吸収が行われる。以上のように、衝突物の種類により波形状部材１やブラケット３等の変形状態は異なるが、外力による衝撃エネルギーは十分に吸収され、かつリヤボディパネル１０側の変形が防止される結果となる。また、衝撃吸収孔２５は図示では６個の丸孔としたが、数及び形状は図示のものに限定するものではない。
【００１７】
【発明の効果】
本発明の車体用バンパ構造によれば、車体側とバンパとの間に前記バンパの全長とほぼ等しい全長の衝撃吸収部材を介在させ、該衝撃吸収部材は外力の作用時にその作用方向に変形するため、衝撃エネルギーを十分に吸収することができる。また、衝撃エネルギーの吸収が衝撃吸収部材のみで不十分な場合はシャシフレーム側で衝撃力を受ける。これにより、車体側への損傷が防止される。また、衝撃吸収部材はバンパと別体のため、取り付け，取り外し作業が簡単に操作でき、かつバンパまわりの構造の簡易化が図れる。また、外力作用時には衝撃吸収孔を基点として座屈が始まるため、座屈の進行が均一化され、予め想定した変形が行われ外力作用時における変形状態を想定することができる。また、衝撃吸収部材が複数の波形を形成する波形状部材からなり、波形の変形により十分に衝撃力を吸収することができる。また、波形状部材は車体側に安定保持される。
【図面の簡単な説明】
【図１】本発明の車体用バンパの全体構造を示す断面図。
【図２】本発明に使用される波形状部材及びこれを支持するブラケットの詳細構造を示す斜視図。
【図３】車体のリヤボディの後端の概要構造を示す部分斜視図。
【図４】本発明の車体用バンパ構造の外力作用時における波形状部材の変形状態を示す模式図。
【図５】比較的大きな外力作用時における本発明の車体用バンパ構造の変形状態を示す模式図。
【図６】本発明における波形状部材の外力作用前の状態を示す模式図。
【図７】図６に示した波形状部材にポール状の衝突物が作用した場合の変形状態を示す模式図。
【図８】図６に示した波形状部材に平板状の衝突物が作用した場合の変形状態を示す模式図。
【図９】従来の車体用バンパ構造の一例を示す断面図。
【符号の説明】
１波形状部材
２波形
３ブラケット
４当接部
５フランジ部
６取り付け孔
７取り付け孔
８ボルト
９ナット
１０リヤボディパネル
１１ボルト
１２リヤバンパ
１３シャシフレーム
１４クロスメンバ
１５開口部
１６リヤドアパネル
１７リヤエンドパネル
１８テールランプ
１９フランジ
２０ボルト
２１ポール
２２平板状衝突物
２５衝撃吸収孔[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bumper structure attached to a vehicle body side, and more particularly to a vehicle body bumper structure suitable for absorbing impact energy when an external force is applied.
[0002]
[Prior art]
Bumpers are attached to the front and back of the car to protect the car. For example, FIG. 9 shows a conventional bumper structure attached to the rear of an automobile. A rear body panel 10 is provided at the rear of the automobile, and a rear bumper 12 is disposed behind the rear bumper 12 to prevent external force from directly acting on the rear body panel 10. Many conventional rear bumpers 12 are fixed to the chassis frame 13 side as shown in the figure, and are not fixed to the rear body panel 10 side. That is, the reinforcement 24 is fixed to the rear end side of the back bar 23 whose base end side is fixed to the chassis frame 13, and the rear bumper 12 is fixed to the reinforcement 24.
[0003]
[Problems to be solved by the invention]
When an external force acts on the rear bumper 12 shown in FIG. 9, the impact force acts on the reinforcement 24 and the chassis frame 13 through the rear bumper 12. Since these are relatively high in rigidity, the amount of deformation is small and the rear body panel 10 is not damaged. However, the degree of absorption of impact energy is small, and a large impact force acts on the automobile. On the other hand, as a recent trend, one that directly fixes the bumper to the vehicle body side is adopted. That is, the one that directly fixes the base end side of the rear bumper 12 to the rear body panel 10 side in FIG. 9 is employed. Therefore, if a means for absorbing impact energy is not provided on the rear bumper 12 side, there is a problem that an external force acts directly on the rear body panel 10 side and deforms it.
[0004]
There are various known techniques for providing shock absorbing members in and around the bumper. For example, Japanese Utility Model Laid-Open No. 59-110754, Japanese Utility Model Laid-Open No. 59-151756, Japanese Utility Model Laid-Open No. 61-193846, and the like. Japanese Utility Model Laid-Open No. 59-110754 discloses an “automobile bumper structure” in which a collision energy absorbing member is fixed to the strength member of an automobile bumper formed by combining a skin material and a strength member, Is disposed close to the skin material, and the collision energy absorbing member is brought into contact with the skin material when an external force is applied to absorb the collision energy. In addition, the “bumper structure for automobiles” disclosed in Japanese Utility Model Publication No. 59-151756 is provided with a deformable portion capable of absorbing collision energy in a stay for fixing the bumper to the vehicle body member. It absorbs collision energy. In addition, an “automobile bumper” disclosed in Japanese Utility Model Laid-Open No. 61-193848 has an inner part formed in a hollow shape inside a bumper body, and a bellows part is provided on the inner part. / Or fixed to the body side of the car.
[0005]
All of the above known techniques effectively absorb collision energy when an external force is applied, and have an effect of preventing deformation on the vehicle body side. However, these are all mounted on the bumper side and are not arranged separately from the bumper. Further, the collision absorbing portion is not formed over the entire length in the longitudinal direction of the bumper, but is disposed partially. Therefore, depending on the form of the external force acting on the bumper, there is often a possibility that the collision energy is not sufficiently absorbed. Further, as described above, since the structure is integrated with the bumper, the bumper itself is costly and requires a lot of time for assembly. Moreover, in these known techniques, consideration when a very large external force is applied is insufficient.
[0006]
The present invention was devised in view of the above circumstances, and is a bumper structure that is held on the vehicle body side, and can sufficiently absorb impact energy when an external force of various forms is applied. It is an object of the present invention to provide a bumper structure for a vehicle body that functions to reduce deformation on the vehicle body side even when an external force is applied, that is relatively simple and inexpensive to implement, and that can be assembled relatively easily.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is arranged to be held on the vehicle body side and opposed to the end portion of the chassis frame through an appropriate interval, and to absorb impact energy when an external force is applied. A bumper structure having a length substantially the same as the entire length of the bumper between the vehicle body side and the inner surface of the bumper, and a separate shock absorbing member that deforms along the direction of action of the external force. The shock absorbing member is disposed so as to abut against the bumper at least before the end of the chassis frame when the external force is applied, and its cross section is formed in a wave shape, and is buckled when the external force is applied. A shock absorbing hole serving as a base point is provided.
[0008]
The bumper is held on the vehicle body side, and a separate shock absorbing member is interposed between the vehicle body side and the inner surface of the bumper. In addition, the bumper is disposed opposite to the end of the chassis frame, and when no external force is applied, the bumper is disposed at a position spaced from the end of the shock absorbing member and the chassis frame. Is placed closer to the bumper. When an external force is applied, the bumper first strikes the impact absorbing member, and the impact energy is absorbed. Furthermore, when a large external force is applied, the impact absorbing member is further deformed and the bumper hits the end of the chassis frame, and the deformation absorbs the impact energy. As described above, deformation on the vehicle body side is prevented when an external force is applied. When repairing the vehicle body, the bumper and the separate shock absorbing member may be replaced, and the repair cost is relatively low. Further, since the shock absorbing member is a separate member, assembly and replacement can be performed relatively easily, and workability can be improved.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a vehicle body bumper structure of the present invention will be described in detail with reference to the drawings. In this example, a rear bumper mounted on the rear body panel side of the vehicle body will be described, but the present invention is not limited to this. As shown in FIGS. 1 and 3, the rear body panel 10 is disposed below the rear door panel 16 that opens and closes the opening 15 at the rearmost portion of the vehicle body. A chassis frame 13 is disposed below the chassis frame 13, and a cross member 14 is disposed between the ends of the left and right chassis frames 13 at the end of the chassis frame 13. Further, a tail lamp 18 or the like is attached to the rear end panel 17 that forms the opening 15.
[0010]
The rear bumper 12 is made of a member having a cross-sectional shape as shown in FIG. 1, and a flange 19 on the base end side thereof is fixed to the rear body panel 10 with bolts 20 or the like. That is, the rear bumper 12 is held on the rear body panel 10 in a cantilever state. On the other hand, the corrugated member 1 as an impact absorbing member is disposed on the upper side of the chassis frame 13 between the rear body panel 10 and the inner surface of the rear bumper 12 and is connected to the rear body panel 10 by the bracket 3 as will be described in detail later. The As shown in FIG. 2, shock absorbing holes 25 are formed in the corrugated member 1. At the time of a collision or the like, the corrugated member 1 is buckled with the shock absorbing hole 25 as a base point.
[0011]
FIG. 2 shows the detailed structure of the corrugated member 1 in this example. The corrugated member 1 is formed of an elongated plate having a length substantially equal to the entire length of the rear bumper 12, and has a plurality of (three in the drawing) corrugations 2 as a cross-sectional shape. The material, plate thickness, etc. are not particularly limited as long as they have a function capable of sufficiently absorbing the impact force acting on the automobile. In this example, the bracket 3 is connected to both end sides of the corrugated member 1, and as shown in FIG. 1, the abutting portion 4 that abuts the lower surface of the corrugated member 1, and the abutting portion 4 is orthogonal. And a flange portion 5 fixed to the rear body panel 10 side. Two attachment holes 6 are formed in the bracket 3 in this example, and two attachment holes 7 are also formed at the position of the corrugated member 1 corresponding thereto. The bracket 3 and the corrugated member 1 are fixed by bolts 8 and nuts 9, but the inner diameter of the mounting hole 7 of the corrugated member 1 is formed larger than the diameter of the bolt 8, and only the difference in diameter is obtained. The corrugated member 1 becomes movable. The flange portion 5 is fixed to the rear body panel 10 with bolts 11 or the like. Accordingly, the corrugated member 1 is cantilevered on the rear body panel 10 side via the bracket 3. In this state, a gap a is formed between the end of the corrugated member 1 on the rear bumper 12 side and the inner surface of the rear bumper 12.
[0012]
As described above, the cross member 14 is fixed to the rear end portion of the chassis frame 13, and the cross member 14 is disposed opposite to the inner surface of the rear bumper 12. The distance b between the cross member 14 and the inner surface of the rear bumper 12 is larger than the distance a between the end of the corrugated member 1 and the inner surface of the rear bumper 12.
[0013]
Next, the absorption state of impact energy when an external force is applied to the rear bumper 12 in this example will be described with reference to the schematic diagrams of FIGS. When an external force F acts on the rear bumper 12, the rear bumper 12 itself is deformed, the interval a is eliminated, and the inner surface of the rear bumper 12 hits the end of the corrugated member 1. Further, when the rear bumper 12 is deformed, the corrugated member 1 starts to buckle with the shock absorbing hole 25 as a base point, the waveform 2 gradually collapses, and the whole contracts to absorb the impact energy due to the external force F. In this case, the corrugated member 1 is supported by the bracket 3, but since the mounting hole 7 to the bracket 3 is larger than the diameter of the bolt 8, only the corrugated member 1 first moves in the contracting direction by the action of the external force F. Then, an external force acts on the bracket 3. However, as will be described later, since the bracket 3 has higher rigidity than the corrugated member 1, the deformation amount of the portion of the corrugated member 1 connected to the bracket 3 is smaller than that of the other portions. As described above, the corrugated member 1 is partially different in the amount of deformation, but absorbs impact energy due to the external force F by deformation over its entire length.
[0014]
When an external force F ₁ greater than the external force F is applied, the deformation of the rear bumper 12 further proceeds and the deformation of the corrugated member 1 also increases. Therefore, the inner surface of the rear bumper 12 hits the end surface of the cross member 14 and further deforms the cross member 14. In this state, the impact energy due to the external force F ₁ is absorbed by the deformation of the wave member 1 and the deformation of the cross member 14. However, since the cross member 14 itself has a relatively high rigidity, its deformation amount is small and deformation on the rear body panel 10 side can be prevented. As described above, both effects of absorbing impact energy due to external force and preventing deformation of the rear body panel 10 can be improved. Further, as described above, in the case of this example, since the impact energy is absorbed by the corrugated member 1 having the entire length close to the lateral width of the vehicle, the impact energy absorption rate can be greatly improved as compared with the conventional technology. it can. Further, the corrugated member 1 is separate from the rear bumper 12 and can be appropriately set according to the type of vehicle. Further, the shape of the waveform 2 can be arbitrarily formed. Furthermore, it is easy to replace the corrugated member 1 deformed by an external force, and the mounting work in the case of a new vehicle is also easy because it is performed separately from the mounting of the rear bumper 12.
[0015]
Next, FIG. 6 to FIG. 8 schematically show the waveform state in the longitudinal direction of the corrugated member 1 corresponding to the type of colliding object colliding with the rear bumper 12 side. FIG. 6 schematically shows the corrugated member 1 and the bracket 3 that supports the corrugated member 1 before the action of an external force. First, as shown in FIG. 7, a case where the collision object is a pole 21 will be described. When the pole 21 comes into contact with the center of the rear bumper 12, the central portion of the corrugated member 1 is greatly deformed, and the portions other than the central portion are deformed accordingly. The impact energy is absorbed by the above deformation. In this case, since the action of the external force on the bracket 3 side is relatively small, the deformation on the bracket 3 side is small.
[0016]
Next, as shown in FIG. 8, when the flat collision object 22 acts on the rear bumper 12 side, the entire rear bumper 12 and the corrugated member 1 are deformed. Even in this case, the corrugated member 1 is most easily deformed at the center, but the amount of deformation is smaller than that when the pole 21 shown in FIG. 7 acts, and the corrugated member 1 is deformed as a whole, and impact energy is reduced. Absorb. Furthermore, when the external force by the flat collision object 22 is large, the bracket 3 side is also moved by the dimension δ as shown in FIG. 8, and the impact energy is absorbed. As described above, although the deformation state of the corrugated member 1 and the bracket 3 differs depending on the type of the collision object, the impact energy due to the external force is sufficiently absorbed, and the deformation on the rear body panel 10 side is prevented. . The shock absorbing holes 25 are six round holes in the drawing, but the number and shape are not limited to those shown in the drawing.
[0017]
【The invention's effect】
According to the vehicle body bumper structure of the present invention, an impact absorbing member having a full length substantially equal to the entire length of the bumper is interposed between the vehicle body side and the bumper, and the impact absorbing member is deformed in the acting direction when an external force is applied. Therefore, the impact energy can be absorbed sufficiently. Further, when the impact energy is not sufficiently absorbed only by the impact absorbing member, the chassis frame receives an impact force. Thereby, the damage to the vehicle body side is prevented. In addition, since the shock absorbing member is separate from the bumper, it can be easily attached and detached, and the structure around the bumper can be simplified. Further, since the buckling starts from the shock absorbing hole as a base point when the external force is applied, the progress of the buckling is made uniform, and the deformation assumed in advance is performed, so that the deformation state when the external force is applied can be assumed. In addition, the impact absorbing member is formed of a corrugated member that forms a plurality of corrugations, and the impact force can be sufficiently absorbed by the deformation of the corrugations. Further, the corrugated member is stably held on the vehicle body side.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the overall structure of a vehicle body bumper according to the present invention.
FIG. 2 is a perspective view showing a detailed structure of a corrugated member used in the present invention and a bracket that supports the corrugated member.
FIG. 3 is a partial perspective view showing a schematic structure of a rear end of a rear body of the vehicle body.
FIG. 4 is a schematic view showing a deformed state of a corrugated member when an external force is applied to the vehicle body bumper structure of the present invention.
FIG. 5 is a schematic view showing a deformation state of the vehicle body bumper structure of the present invention when a relatively large external force is applied.
FIG. 6 is a schematic view showing a state before the external force action of the corrugated member in the present invention.
7 is a schematic diagram showing a deformed state when a pole-shaped collision object acts on the corrugated member shown in FIG. 6. FIG.
FIG. 8 is a schematic diagram showing a deformed state when a flat collision object acts on the corrugated member shown in FIG. 6;
FIG. 9 is a cross-sectional view showing an example of a conventional vehicle body bumper structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Corrugated member 2 Corrugated 3 Bracket 4 Contact part 5 Flange part 6 Mounting hole 7 Mounting hole 8 Bolt 9 Nut 10 Rear body panel 11 Bolt 12 Rear bumper 13 Chassis frame 14 Cross member 15 Opening part 16 Rear door panel 17 Rear end panel 18 Tail lamp 19 Flange 20 Bolt 21 Pole 22 Flat collision object 25 Shock absorption hole

Claims

A bumper structure that is held on the vehicle body side and is disposed opposite to the end of the chassis frame with an appropriate gap therebetween, and is formed to absorb impact energy when an external force is applied. A separate shock absorbing member that has a length substantially the same as the entire length of the bumper and is deformed along the direction of the external force is interposed between the inner surface and the inner surface of the bumper. At least before the end of the chassis frame, the bumper is disposed so as to contact the bumper , the cross section thereof is formed in a wave shape, and a shock absorbing hole serving as a base point for buckling when an external force is applied is provided. Body bumper structure.