JP2014040209A

JP2014040209A - Vehicle body lower structure of vehicle

Info

Publication number: JP2014040209A
Application number: JP2012184205A
Authority: JP
Inventors: Kan Senda; 款先田; Nobuya Nakade; 暢也中出
Original assignee: Daihatsu Motor Co Ltd
Current assignee: Daihatsu Motor Co Ltd
Priority date: 2012-08-23
Filing date: 2012-08-23
Publication date: 2014-03-06

Abstract

PROBLEM TO BE SOLVED: To prevent a vehicle body from being uselessly largely deformed, by further effectively relieving impact force, by preventing a side member of the vehicle body from easily buckling by the impact force in a head-on collision.SOLUTION: A plate material positioned on one side among outside plate materials 33 and 34 in a front bending part 26 of a side member 12, is formed in a cross-sectional U shape of opening toward the other side of a vehicle body 2, and a plate material positioned on the other side among the inside-outside plate materials 33 and 34 in a rear bending part 28, is formed in a cross-sectional U shape of opening toward the one side. A junction part of mutual respective lower end parts of the inside-outside plate materials 33 and 34 in a middle part member 27 and a junction part of mutual both outer flanges 35 and 35, are gradually displaced toward the side part side of one side from the side part side of the other side in the middle part member 27 toward the rear part side from the front part side of the middle part member 27. The middle part member 27 and front-rear bending parts 26 and 28 are respectively positioned under a swelling part 19 of a floor panel 16.

Description

本発明は、全体として車体のほぼ前後方向に延び、その長手方向における中途部の前、後端部がそれぞれ屈曲して、上記中途部が後方に向かうに従い車体の一側方もしくは他側方の傾斜方向に向かって延びるサイドメンバを備えた車両の車体下部構造に関するものである。 The present invention as a whole extends substantially in the front-rear direction of the vehicle body, the front and rear end portions of the midway portion in the longitudinal direction are bent, and the midway portion is directed to one side or the other side of the vehicle body toward the rear. The present invention relates to a vehicle body lower part structure including a side member extending in an inclined direction.

上記車両の車体下部構造には、従来、下記特許文献１に示されるものがある。この公報のものによれば、車両の車体下部構造は、車体の幅方向で互いに離れて位置する左右一対のサイドメンバと、これら左右サイドメンバ上に支持されるフロアパネルと、このフロアパネルの前後方向の中途部を上方に膨出させて形成され、その内部空間にエンジンを収容する膨出部とを備えている。 Conventionally, the vehicle body lower part structure of the vehicle is disclosed in Patent Document 1 below. According to this publication, the lower body structure of the vehicle includes a pair of left and right side members that are located apart from each other in the width direction of the vehicle body, a floor panel supported on the left and right side members, and front and rear sides of the floor panel. A midway portion in the direction is formed to bulge upward, and a bulge portion for accommodating the engine is provided in the internal space.

上記サイドメンバは、その前部を構成して車体の前後方向に延びる前部メンバと、この前部メンバの後端部から前部屈曲部を経て後方かつ車体の外側方に向かって延びる中途部メンバと、この中途部メンバの後端部から後部屈曲部を経て車体の前後方向に延びる後部メンバとを有している。 The side member includes a front member that forms a front portion thereof and extends in the front-rear direction of the vehicle body, and a midway portion that extends rearward from the rear end portion of the front member through the front bent portion and toward the outside of the vehicle body. A member, and a rear member extending in the front-rear direction of the vehicle body from the rear end portion of the midway member through the rear bent portion.

上記サイドメンバは、断面Ｕ字形状のメンバ本体部と、このメンバ本体部の上端開口を閉じるようこのメンバ本体の左右側板の各上端縁部に架設されて接合される上面板とを有している。 The side member includes a member main body portion having a U-shaped cross section, and an upper surface plate that is erected and joined to each upper edge of the left and right side plates of the member main body so as to close the upper end opening of the member main body portion. Yes.

特開平１０−２１８０３３号公報Japanese Patent Laid-Open No. 10-218033

ところで、上記構成の車両の前進走行中に、この車両がその前方の何らかの物体に衝突（前突）したときには、この物体から上記各サイドメンバに対しその長手方向に向かって大きい衝撃力が与えられる。この場合、上記サイドメンバの各部にはそれぞれ圧縮応力が生じるが、特に、上記前、後部屈曲部においては、それぞれ屈曲半径が大きい側部よりも屈曲半径が小さい側部に対し、より大きい圧縮応力が集中しがちとなる。 By the way, when the vehicle having the above configuration travels forward, when this vehicle collides with a certain object ahead (front collision), a large impact force is applied from the object to the side members in the longitudinal direction. . In this case, a compressive stress is generated in each part of the side member. In particular, in the front and rear bent parts, a larger compressive stress is applied to a side part having a smaller bending radius than a side part having a larger bending radius. Tend to concentrate.

このため、前突時には、上記前、後部屈曲部における元の屈曲状態が上記前突による衝撃力によって更に進行するよう屈曲させられがちとなる。この結果、前突時には、上記サイドメンバは上記前、後部屈曲部を起点として直ちに容易に座屈するおそれを生じる。そして、この場合には、上記サイドメンバの長手方向の各部がそれぞれ変形することは防止されるため、上記衝撃力のエネルギーを効果的に吸収することが阻害されて、この衝撃力の緩和が不十分になりがちとなる。また、上記したサイドメンバの座屈により、車体が無用に大きく変形するおそれもある。 For this reason, at the time of a front collision, the original bent state at the front and rear bent portions tends to be bent so as to further advance by the impact force of the front collision. As a result, at the time of a front collision, the side member may easily buckle immediately starting from the front and rear bent portions. In this case, since the respective portions of the side members in the longitudinal direction are prevented from being deformed, effective absorption of the energy of the impact force is hindered, and relaxation of the impact force is impeded. It tends to be enough. Further, the vehicle body may be unnecessarily greatly deformed due to the buckling of the side members.

そこで、上記サイドメンバの前、後部屈曲部における各メンバ本体部の左右側板に跨るようそれぞれ別途の補強材を設けて、上記衝撃力による上記各屈曲部の屈曲を抑制し、これにより、前突時の衝撃力により上記サイドメンバが容易には座屈しないようにすることが考えられる。 Therefore, a separate reinforcing material is provided so as to straddle the left and right side plates of each member main body at the front and rear bent portions of the side member to suppress the bending of the bent portions due to the impact force, thereby It can be considered that the side member is not easily buckled by the impact force of time.

しかし、上記サイドメンバの前、後部屈曲部に別途の補強材を設けると、車体の構成部品が増加して車体の形成が煩雑となったり、車体の質量が重くなったりして、車体の生産性が低下するという不都合を生じる。 However, if separate reinforcing members are provided at the front and rear bent portions of the side members, the number of components of the vehicle body increases and the formation of the vehicle body becomes complicated, and the mass of the vehicle body becomes heavy. Inconvenience that the performance is lowered.

しかも、前記したように、サイドメンバ上にはフロアパネルが支持されており、このため、上記補強材を設けようとする際、上記フロアパネルが邪魔になるおそれがある。そして、この場合、上記フロアパネルを避けて、上記補強材を設けようとすると、その分、車体の形成が煩雑となり、この点でも、車体の生産性が低下するおそれを生じる。 In addition, as described above, the floor panel is supported on the side member, and therefore the floor panel may become an obstacle when the reinforcing material is provided. In this case, if the reinforcing material is provided so as to avoid the floor panel, the formation of the vehicle body becomes complicated accordingly, and the productivity of the vehicle body may be lowered in this respect as well.

本発明は、上記のような事情に注目してなされたもので、本発明の目的は、前突時に、その衝撃力により車体のサイドメンバが容易に座屈することを防止して、上記衝撃力の緩和がより効果的にできるようにすると共に、車体が無用に大きく変形することを防止することである。更に、このようにした場合でも、車体の生産性が良好に維持できるようにすることである。 The present invention has been made paying attention to the above situation, and the object of the present invention is to prevent the side member of the vehicle body from being easily buckled by the impact force at the time of a front collision, and It is possible to prevent the vehicle body from being unnecessarily greatly deformed. Furthermore, even in such a case, the productivity of the vehicle body can be maintained satisfactorily.

請求項１の発明は、車体２の幅方向で互いに離れて位置する左右一対のサイドメンバ１２，１２と、これら左右サイドメンバ１２，１２上に支持されるフロアパネル１６と、このフロアパネル１６の前後方向の中途部を上方に膨出させて形成され、その内部空間１７にエンジン１８を収容する膨出部１９とを備え、
上記サイドメンバ１２が、その前部を構成して車体２の前後方向に延びる前部メンバ２５と、この前部メンバ２５の後端部から前部屈曲部２６を経て後方かつ車体２の一側方に向かって延びる中途部メンバ２７と、この中途部メンバ２７の後端部から後部屈曲部２８を経て車体２の前後方向に延びる後部メンバ２９とを有し、かつ、上記サイドメンバ１２が、車体２の幅方向で互いに対面して各下端縁部が互いに接合される内、外側板材３３，３４と、これら内、外側板材３３，３４の各上端縁部からそれぞれその外方に向かい突出して互いに接合される外向きフランジ３５，３５とを有した車両の車体下部構造において、
上記前部屈曲部２６における上記内、外側板材３３，３４のうちの上記一側方に位置する板材を車体２の他側方に向かって開く断面コの字形状とし、上記後部屈曲部２８における上記内、外側板材３３，３４のうちの上記他側方に位置する板材を上記一側方に向かって開く断面コの字形状とし、
上記中途部メンバ２７における上記内、外側板材３３，３４の各下端部同士の接合部と上記両外向きフランジ３５，３５同士の接合部とが、上記中途部メンバ２７の前部側から後部側に向かうに従いこの中途部メンバ２７における上記他側方の側部がわから上記一側方の側部がわに向けて漸次変位するようにし、
上記膨出部１９の下方に上記中途部メンバ２７と前、後部屈曲部２６，２８とをそれぞれ位置させたことを特徴とする車両の車体下部構造である。 According to the first aspect of the present invention, a pair of left and right side members 12, 12 that are located apart from each other in the width direction of the vehicle body 2, a floor panel 16 that is supported on these left and right side members 12, 12, It is formed by bulging upward a midway part in the front-rear direction, and includes a bulging part 19 that houses the engine 18 in its internal space 17;
The side member 12 constitutes a front portion of the front member 25 extending in the front-rear direction of the vehicle body 2, and a rear side of the front member 25 through the front bent portion 26 and one side of the vehicle body 2. And a rear member 29 extending in the front-rear direction of the vehicle body 2 from the rear end portion of the middle member 27 through the rear bent portion 28, and the side member 12 is The lower edge portions of the vehicle body 2 face each other in the width direction and are joined to each other. The outer plate members 33 and 34 protrude from the upper edge portions of the inner and outer plate members 33 and 34 to the outside. In the vehicle body lower part structure having the outward flanges 35 and 35 joined to each other,
Of the inner and outer plate members 33, 34 in the front bent portion 26, the plate member located on one side is formed into a U-shaped cross section that opens toward the other side of the vehicle body 2, and the rear bent portion 28 Of the inner and outer plate members 33, 34, the plate member located on the other side is a U-shaped cross section that opens toward the one side,
In the midway member 27, the joints between the lower ends of the inner and outer plate members 33, 34 and the joints between the outward flanges 35, 35 are located from the front side to the rear side of the midway member 27. The other side portion of the midway member 27 is gradually displaced from the side toward the side toward the side,
The vehicle body lower part structure of the vehicle is characterized in that the midway member 27 and the front and rear bent portions 26 and 28 are respectively positioned below the bulging portion 19.

なお、この項において、上記各用語に付記した符号や図面番号は、本発明の技術的範囲を後述の「実施例」の項や図面の内容に限定解釈するものではない。 In addition, in this section, the reference numerals and drawing numbers appended to the above terms are not intended to limit the technical scope of the present invention to the “Example” section and the contents of the drawings described later.

本発明による効果は、次の如くである。 The effects of the present invention are as follows.

請求項１の発明は、車体の幅方向で互いに離れて位置する左右一対のサイドメンバと、これら左右サイドメンバ上に支持されるフロアパネルと、このフロアパネルの前後方向の中途部を上方に膨出させて形成され、その内部空間にエンジンを収容する膨出部とを備え、
上記サイドメンバが、その前部を構成して車体の前後方向に延びる前部メンバと、この前部メンバの後端部から前部屈曲部を経て後方かつ車体の一側方に向かって延びる中途部メンバと、この中途部メンバの後端部から後部屈曲部を経て車体の前後方向に延びる後部メンバとを有し、かつ、上記サイドメンバが、車体の幅方向で互いに対面して各下端縁部が互いに接合される内、外側板材と、これら内、外側板材の各上端縁部からそれぞれその外方に向かい突出して互いに接合される外向きフランジとを有した車両の車体下部構造において、
上記前部屈曲部における上記内、外側板材のうちの上記一側方に位置する板材を車体の他側方に向かって開く断面コの字形状とし、上記後部屈曲部における上記内、外側板材のうちの上記他側方に位置する板材を上記一側方に向かって開く断面コの字形状としており、次の効果が生じる。 According to the first aspect of the present invention, a pair of left and right side members positioned apart from each other in the width direction of the vehicle body, a floor panel supported on the left and right side members, and a midway portion in the front-rear direction of the floor panel are expanded upward. A bulge portion that is formed and accommodates the engine in its internal space;
The side member constitutes a front part of the front member that extends in the front-rear direction of the vehicle body, and the middle extends from the rear end portion of the front member through the front bent portion and toward one side of the vehicle body. And a rear member extending in the front-rear direction of the vehicle body from the rear end portion of the midway member through the rear bent portion, and the side members face each other in the width direction of the vehicle body, and each bottom edge In the vehicle body lower part structure of the vehicle having outer plate members that are joined to each other, and outward flanges that project outward from the respective upper edge portions of the inner and outer plate members and are joined to each other.
Of the inner and outer plate members in the front bent portion, the plate member located on one side is formed into a U-shaped cross section that opens toward the other side of the vehicle body, and the inner and outer plate members in the rear bent portion are formed. Of these, the plate located on the other side has a U-shaped cross section that opens toward the one side, and the following effects are produced.

即ち、走行中の車両の前突時には、前記従来の技術にて説明のように、前、後部屈曲部における元の屈曲状態が上記前突による衝撃力により更に進行するよう屈曲させられがちとなり、この結果、前突時には、上記サイドメンバは上記前、後部屈曲部を起点として直ちに容易に座屈するおそれを生じる。 That is, at the time of a frontal collision of a traveling vehicle, as explained in the above-mentioned conventional technology, the original bending state in the front and rear bent parts tends to be bent so as to further progress due to the impact force due to the front collision, As a result, at the time of a front collision, the side member may easily buckle immediately starting from the front and rear bent portions.

しかし、上記発明によれば、前突時の衝撃力により、上記サイドメンバの前、後部屈曲部において、より大きい圧縮応力が集中しがちとなる屈曲半径が小さい側の上記前部屈曲部での外側板材もしくは内側板材と、上記後部屈曲部での内側板材もしくは外側板材とは、それぞれ上記したように断面コの字形状であって、この断面コの字形状において２つの屈曲部が存在する側の底部が、上記した圧縮応力が集中しがちとなる側に位置することとされる。そして、上記した断面コの字形状の底部は、上記各屈曲部の断面がそれぞれアングル形状とされて上記サイドメンバの長手方向に向かって延びる二条の稜線を有することから、上記衝撃力を強固に支持し得る強度構造となっている。 However, according to the above-described invention, due to the impact force at the time of the front collision, the front member at the front bent portion on the side where the bending radius is small, where a larger compressive stress tends to be concentrated at the front and rear bent portions of the side member. The outer plate member or the inner plate member and the inner plate member or the outer plate member at the rear bent portion have a U-shaped cross section as described above, and the side where two bent portions exist in the U-shaped cross section. Is located on the side where the compressive stress tends to concentrate. The bottom of the U-shaped cross-section described above has two ridges extending in the longitudinal direction of the side member so that the cross section of each of the bent portions has an angle shape. It has a strength structure that can be supported.

よって、上記前、後部屈曲部における元の屈曲状態が上記衝撃力により更に進行するよう屈曲させられることは防止され、つまり、上記サイドメンバが上記前、後部屈曲部を起点として容易に座屈することは防止される。この結果、前突時には、その衝撃力によりサイドメンバの長手方向の各部がそれぞれ変形して上記衝撃力のエネルギーが効果的に吸収され、この衝撃力が効果的に緩和されると共に、車体が無用に大きく変形することがより確実に防止される。 Therefore, it is prevented that the original bent state at the front and rear bent portions is further bent by the impact force, that is, the side member is easily buckled starting from the front and rear bent portions. Is prevented. As a result, at the time of a front collision, the impact force causes deformation of each part in the longitudinal direction of the side member, so that the energy of the impact force is effectively absorbed, the impact force is effectively mitigated, and the vehicle body is useless. Can be more reliably prevented from being greatly deformed.

また、上記中途部メンバにおける上記内、外側板材の各下端部同士の接合部と上記両外向きフランジ同士の接合部とが、上記中途部メンバの前部側から後部側に向かうに従いこの中途部メンバにおける上記他側方の側部がわから上記一側方の側部がわに向けて漸次変位するようにしている。 In addition, the intermediate portion of the intermediate member, as the connection portion between the lower ends of the inner and outer plate members and the connection portion between the two outward flanges move from the front side to the rear side of the intermediate member. The side portion on the other side of the member is gradually displaced from the side to the side portion on the one side.

このため、上記中途部メンバの長手方向各部における断面係数は緩やかに変化して、剛性上の断点が生じないことから、上記衝撃力によりサイドメンバの中途部メンバが容易に座屈することも、より確実に防止される。 For this reason, since the section modulus in each part in the longitudinal direction of the midway member changes gently and no stiff point is produced, the midway member of the side member can easily be buckled by the impact force. More reliably prevented.

また、上記した前突時におけるサイドメンバの座屈防止は、このサイドメンバが元来有する内、外側板材や両外向きフランジの形状を工夫することにより達成される。よって、上記サイドメンバの座屈防止は、車体の構成部品の増加や車体の質量の増加を抑制しつつ達成でき、車体の生産性が良好に維持される。 Moreover, the buckling prevention of the side member at the time of the above-mentioned front collision is achieved by devising the shape of the outer side plate material and both outward flanges which the side member originally has. Therefore, the buckling prevention of the side member can be achieved while suppressing an increase in the number of components of the vehicle body and an increase in the mass of the vehicle body, and the productivity of the vehicle body is maintained favorably.

しかも、上記膨出部の下方に上記中途部メンバと前、後部屈曲部とをそれぞれ位置させている。 In addition, the midway member and the front and rear bent portions are positioned below the bulging portion.

このため、上記中途部メンバから外方に突出する両外向きフランジは上記膨出部の内部空間に収容させることができて、上記両外向きフランジが他のものと干渉し合うことは防止される。よって、上記両外向きフランジの突出方向や幅方向の大きさを所望のものにできることから、その分、上記サイドメンバの強度と剛性とを、より向上させることができ、前突時におけるこのサイドメンバの座屈を更に確実に防止できる。 For this reason, both outward flanges protruding outward from the midway member can be accommodated in the internal space of the bulging portion, and the two outward flanges are prevented from interfering with each other. The Therefore, since the projecting direction and the width direction of the both outward flanges can be made as desired, the strength and rigidity of the side member can be further improved, and this side at the time of the front collision Member buckling can be prevented more reliably.

また、上記したように、サイドメンバの両外向きフランジは上記膨出部の内部空間に収容されることから、上記サイドメンバとフロアパネルとが互いに干渉することは防止される。よって、これらサイドメンバやフロアパネルの組み付けは、互いの干渉を避けつつ容易にすることができて、車体の生産性が更に良好に維持される。 Further, as described above, since both outward flanges of the side member are accommodated in the internal space of the bulging portion, the side member and the floor panel are prevented from interfering with each other. Therefore, the assembly of the side members and the floor panel can be facilitated while avoiding mutual interference, and the productivity of the vehicle body can be maintained better.

右側のサイドメンバの部分斜視図および長手方向の各部断面図である。It is the fragmentary perspective view of the right side member, and each part sectional drawing of a longitudinal direction. 車両の簡略側面図である。It is a simplified side view of a vehicle. 車両の簡略平面図である。It is a simplified top view of a vehicle. 図２の部分拡大断面図である。FIG. 3 is a partially enlarged sectional view of FIG. 2. 図１で示したサイドメンバの斜視展開図である。FIG. 2 is a perspective development view of the side member shown in FIG. 1.

本発明の車両の車体下部構造に関し、前突時に、その衝撃力により車体のサイドメンバが容易に座屈することを防止して、上記衝撃力の緩和がより効果的にできるようにすると共に、車体が、無用に大きく変形することを防止する、という目的を実現するため、本発明を実施するための形態は、次の如くである。 The vehicle body lower part structure of the present invention relates to a vehicle body side structure that prevents side members of the vehicle body from easily buckling due to the impact force at the time of a front collision, and can more effectively reduce the impact force. However, in order to realize the object of preventing the large deformation unnecessarily, modes for carrying out the present invention are as follows.

即ち、車両の車体下部構造は、車体の幅方向で互いに離れて位置する左右一対のサイドメンバと、これら左右サイドメンバ上に支持されるフロアパネルと、このフロアパネルの前後方向の中途部を上方に膨出させて形成され、その内部空間にエンジンを収容する膨出部とを備える。 That is, the lower body structure of the vehicle includes a pair of left and right side members that are spaced apart from each other in the width direction of the vehicle body, a floor panel that is supported on the left and right side members, and a middle part in the front-rear direction of the floor panel. And a bulging portion for accommodating the engine in the internal space.

上記サイドメンバは、その前部を構成して車体の前後方向に延びる前部メンバと、この前部メンバの後端部から前部屈曲部を経て後方かつ車体の一側方に向かって延びる中途部メンバと、この中途部メンバの後端部から後部屈曲部を経て車体の前後方向に延びる後部メンバとを有し、かつ、上記サイドメンバが、車体の幅方向で互いに対面して各下端縁部が互いに接合される内、外側板材と、これら内、外側板材の各上端縁部からそれぞれその外方に向かい突出して互いに接合される外向きフランジとを有している。 The side member includes a front member that forms a front portion thereof and extends in the front-rear direction of the vehicle body, and a middle portion that extends rearward from the rear end portion of the front member through the front bent portion and toward one side of the vehicle body. And a rear member extending in the front-rear direction of the vehicle body from the rear end portion of the midway member through the rear bent portion, and the side members face each other in the width direction of the vehicle body, and each bottom edge The outer plate members are joined to each other, and the outer flanges are protruded outward from the respective upper edge portions of the inner and outer plate members and joined to each other.

上記前部屈曲部における上記内、外側板材のうちの上記一側方に位置する板材が車体の他側方に向かって開く断面コの字形状とされる。また、上記後部屈曲部における上記内、外側板材のうちの上記他側方に位置する板材が上記一側方に向かって開く断面コの字形状とされる。 Of the inner and outer plate members in the front bent portion, the plate member positioned on one side is formed in a U-shaped cross section that opens toward the other side of the vehicle body. Further, the plate material located on the other side of the inner and outer plate members in the rear bent portion has a U-shaped cross section that opens toward the one side.

上記中途部メンバにおける上記内、外側板材の各下端部同士の接合部と上記両外向きフランジ同士の接合部とは、上記中途部メンバの前部側から後部側に向かうに従いこの中途部メンバにおける上記他側方の側部がわから上記一側方の側部がわに向けて漸次変位することとされる。 In the midway member, the joint between the lower ends of the inner and outer plate members and the joint between the two outward flanges are located in the midway member from the front side to the rear side of the midway member. The side portion on the other side is gradually displaced toward the side from the side portion on the other side.

上記膨出部の下方に上記中途部メンバと前、後部屈曲部とがそれぞれ位置させられる。 The midway member and the front and rear bent portions are respectively positioned below the bulging portion.

本発明をより詳細に説明するために、その実施例を添付の図に従って説明する。 In order to explain the present invention in more detail, an embodiment thereof will be described with reference to the accompanying drawings.

図２〜４において、符号１は、キャブオーバ型トラックの自動車で例示される車両で、矢印Ｆｒは、この車両１の進行方向の前方を示している。また、下記する左右とは、上記前方に向かっての車両１の車体２の幅方向をいうものとする。 2 to 4, reference numeral 1 denotes a vehicle exemplified by an automobile of a cab over type truck, and an arrow Fr indicates the front in the traveling direction of the vehicle 1. The left and right described below refer to the width direction of the vehicle body 2 of the vehicle 1 toward the front.

上記車体２は、その下端部側を構成して車体２の前後方向に長く延び、この車体２の骨格部材とされる車体フレーム３と、車体２の前上部側を構成し、内部が運転室４としての車室とされて上記車体フレーム３の前部に支持される運転台５と、車体２の後上部側を構成して上記車体フレーム３の後部側に支持される荷台６と、上記車体フレーム３に支持されて車体２を走行路面７上に支持する前、後車輪８，８とを備えている。 The vehicle body 2 constitutes a lower end side thereof and extends long in the front-rear direction of the vehicle body 2, and constitutes a vehicle body frame 3 that is a skeleton member of the vehicle body 2 and a front upper side of the vehicle body 2. 4, a driver's cab 5 that is supported in the front portion of the vehicle body frame 3, and a loading platform 6 that constitutes the rear upper side of the vehicle body 2 and is supported on the rear side of the vehicle body frame 3, Before and after the vehicle body 2 is supported on the traveling road surface 7 by being supported by the vehicle body frame 3, rear wheels 8 and 8 are provided.

上記車体２は、この車体２の幅方向で互いに離れて位置し、それぞれ車体２の前後方向に延びる左右一対の板金製サイドメンバ１２，１２と、これら左右サイドメンバ１２，１２を互いに結合させる前後方向で複数設けられるクロスメンバ１３とを有し、上記車体フレーム３は、車体２の幅方向の中央部を通る車体中心線１４を基準として左右対称形とされている。 The vehicle body 2 is located at a distance from each other in the width direction of the vehicle body 2, and a pair of left and right sheet metal side members 12, 12 that extend in the front-rear direction of the vehicle body 2, and The vehicle body frame 3 is symmetrical with respect to a vehicle body center line 14 that passes through the central portion of the vehicle body 2 in the width direction.

上記運転台５は、その運転室４の下面を形成して上記左右サイドメンバ１２，１２上に支持される板金製フロアパネル１６と、このフロアパネル１６の前後方向の中途部を上方に膨出させて形成され、その内部空間１７にエンジン１８を収容する膨出部１９と、この膨出部１９の上面板に形成され、上記エンジン１８の保守、点検作業用とされる作業開口２０と、上記膨出部１９の上面に支持され上記作業開口２０を開閉可能に閉じる乗員用のシート２１とを有している。この場合、上記フロアパネル１６と膨出部１９とは互いに別体とされて、スポット溶接により結合されている。なお、これらフロアパネル１６と膨出部１９とは互いに一体的に形成してもよい。 The cab 5 forms a lower surface of the cab 4 and is supported on the left and right side members 12 and 12, and a middle part of the floor panel 16 in the front-rear direction bulges upward. A bulging portion 19 that accommodates the engine 18 in the internal space 17, a work opening 20 that is formed on the upper surface plate of the bulging portion 19 and is used for maintenance and inspection work of the engine 18, An occupant seat 21 is supported by the upper surface of the bulging portion 19 and closes the work opening 20 so as to be openable and closable. In this case, the floor panel 16 and the bulging portion 19 are separated from each other and coupled by spot welding. The floor panel 16 and the bulging portion 19 may be formed integrally with each other.

図１，４，５において、上記左右サイドメンバ１２，１２は互いに同様の構成であるため、右側のサイドメンバ１２につき詳しく説明し、左側のサイドメンバ１２については説明を省略する。 1, 4 and 5, since the left and right side members 12 and 12 have the same configuration, the right side member 12 will be described in detail, and the description of the left side member 12 will be omitted.

上記サイドメンバ１２は、上記膨出部１９よりも前方に位置して上記サイドメンバ１２の前部を構成し、車体２の前後方向に直線的に延びる前部メンバ２５と、この前部メンバ２５の後端部から前部屈曲部２６を経て後方かつ車体２の一側方（外側方：ＯＵＴ）に向かって直線的に延びる中途部メンバ２７と、上記膨出部１９よりも後方に位置して上記サイドメンバ１２の後部側を構成し、上記中途部メンバ２７の後端部から後部屈曲部２８を経て車体２の前後方向に直線的に延びる後部メンバ２９とを有している。 The side member 12 is positioned in front of the bulging portion 19 and constitutes a front portion of the side member 12. The front member 25 extends linearly in the front-rear direction of the vehicle body 2, and the front member 25. A midway member 27 that extends rearward from the rear end of the vehicle 2 through the front bent portion 26 and linearly toward one side (outer side: OUT) of the vehicle body 2, and is located behind the bulging portion 19. And a rear member 29 that linearly extends in the front-rear direction of the vehicle body 2 from the rear end portion of the midway member 27 through the rear bent portion 28.

また、上記サイドメンバ１２は、車体２の幅方向で互いに対面して互いに別体として設けられる内、外側板材３３，３４と、これら内、外側板材３３，３４の各上端縁部からそれぞれその外方に向かい一体的に突出して互いにスポット溶接により接合される左右一対の外向きフランジ３５，３５と、上記内、外側板材３３，３４の各下端縁部からそれぞれその外方に向かい一体的に突出して互いにスポット溶接により接合される左右一対の他の外向きフランジ３６，３６とを有して、その長手方向の各部断面が中空閉断面構造とされている。 Further, the side members 12 are provided as separate bodies facing each other in the width direction of the vehicle body 2, and the outer plate members 33 and 34, and the upper edge portions of the inner and outer plate members 33 and 34, respectively. And a pair of left and right outward flanges 35, 35 that are integrally protruded toward each other and are joined together by spot welding, and project from the lower end edges of the inner and outer plate members 33, 34 toward the outer side. Thus, a pair of left and right outward flanges 36 and 36 joined together by spot welding are provided, and each cross section in the longitudinal direction has a hollow closed cross-sectional structure.

上記内側板材３３と、この内側板材３３から突出する外向きフランジ３５および他の外向きフランジ３６とは、上記サイドメンバ１２における車体２の幅方向での内側部分を一体的に形成する。また、上記外側板材３４と、この外側板材３４から突出する外向きフランジ３５および他の外向きフランジ３６とは、上記サイドメンバ１２における車体２の幅方向での外側部分を一体的に形成する。 The inner plate member 33, the outward flange 35 protruding from the inner plate member 33, and the other outward flange 36 integrally form an inner portion of the side member 12 in the width direction of the vehicle body 2. The outer plate member 34, the outward flange 35 protruding from the outer plate member 34, and the other outward flange 36 integrally form an outer portion of the side member 12 in the width direction of the vehicle body 2.

上記前部屈曲部２６における上記内、外側板材３３，３４のうちの上記一側方（外側方：ＯＵＴ）に位置する板材（図例では外側板材３４）は、車体２の他側方（内側方：ＩＮ）に向かって開く断面コの字形状とされる。また、上記後部屈曲部２８における上記内、外側板材３３，３４のうちの上記他側方（内側方：ＩＮ）に位置する板材（図例では内側板材３３）は、上記一側方（外側方：ＯＵＴ）に向かって開く断面コの字形状とされる。 The plate member (outer plate member 34 in the illustrated example) located on one side (outer side: OUT) of the inner and outer plate members 33 and 34 in the front bent portion 26 is the other side (inner side) of the vehicle body 2. Direction: a U-shaped cross section that opens toward IN). Further, the plate member (inner plate member 33 in the illustrated example) located on the other side (inner side: IN) of the inner and outer plate members 33, 34 in the rear bent portion 28 is the one side (outer side). : U-shaped cross-section opening toward OUT).

上記の場合、中途部メンバ２７における上記内、外側板材３３，３４の上記両外向きフランジ３５，３５同士の接合部と、上記両他の外向きフランジ３６，３６同士の接合部とは、上記中途部メンバ２７の前部側から後部側に向かうに従いこの中途部メンバ２７における上記他側方（内側方）の側部がわから上記一側方（外側方）の側部がわに向けて漸次変位することとされている。また、上記各接合部は後方に向かうに従い一側方（外側方）に向かって直線的に延びている。 In the above case, the joint portion between the two outward flanges 35, 35 of the inner and outer plate members 33, 34 in the midway member 27 and the joint portion between the other outward flanges 36, 36 are as described above. As the midway member 27 moves from the front side toward the rear side, the other side (inner side) side portion of the midway member 27 gradually changes from the one side (outer side) side toward the side. It is supposed to be displaced. Moreover, each said junction part is linearly extended toward one side (outer side) as it goes back.

具体的には、上記前部屈曲部２６では内側板材３３よりも外側板材３４の屈曲半径が小さくなることとされ、この外側板材３４が上記他側方（内側方）に向かって開く断面コの字形状とされている。また、上記後部屈曲部２８では外側板材３４よりも内側板材３３の屈曲半径が小さくなることとされ、この内側板材３３が上記一側方（外側方）に向かって開く断面コの字形状とされている。 Specifically, the bending radius of the outer plate 34 is smaller than that of the inner plate 33 at the front bent portion 26, and the outer plate 34 opens to the other side (inner side). It is shaped like a letter. In the rear bent portion 28, the bending radius of the inner plate member 33 is smaller than that of the outer plate member 34, and the inner plate member 33 has a U-shaped cross section that opens toward the one side (outer side). ing.

上記両外向きフランジ３５，３５は、上記前部メンバ２５においては、その内、外側板材３３，３４から車体２の他側方（内側方）に向かって突出し、上記後部メンバ２９においては、その内、外側板材３３，３４から車体２の一側方（外側方）に向かって突出している。これにより、上記前部メンバ２５と後部メンバ２９との各上面はそれぞれ平坦形状とされてこれら各上面に前記フロアパネル１６が面接合され、これにより、このフロアパネル１６は強固に支持されている。 Both the outward flanges 35, 35 protrude from the outer side plate members 33, 34 toward the other side (inner side) of the vehicle body 2 in the front member 25, and in the rear member 29, Projecting from the inner and outer plate members 33 and 34 toward one side (outer side) of the vehicle body 2. Accordingly, the upper surfaces of the front member 25 and the rear member 29 are flattened, and the floor panel 16 is surface-bonded to the upper surfaces, whereby the floor panel 16 is firmly supported. .

また、上記両外向きフランジ３５，３５は、上記中途部メンバ２７の長手方向の中途部においては、その内、外側板材３３，３４から上方に向かって突出し、上記前部屈曲部２６と中途部メンバ２７の前端部側とにおいては、後方に向かうに従い車体２の他側方（内側方）に向かう突出姿勢から上方に向かう突出姿勢に徐々に変化するよう傾斜方向に向かって突出している。また、上記両外向きフランジ３５，３５は、上記中途部メンバ２７の後端部側と後部屈曲部２８とにおいては、後方に向かうに従い上方に向かう突出姿勢から車体２の一側方（外側方）に向かう突出姿勢に徐々に変化するよう傾斜方向に向かって突出している。 Further, the two outward flanges 35, 35 protrude upward from the outer side plate members 33, 34 in the midway portion in the longitudinal direction of the midway member 27, and the front bent portion 26 and the midway portion On the front end side of the member 27, it protrudes in an inclined direction so as to gradually change from a protruding posture toward the other side (inner side) of the vehicle body 2 toward a rearward direction as it goes rearward. In addition, the outward flanges 35, 35 are arranged on one side (outside side) of the vehicle body 2 from the protruding posture toward the upper side toward the rear at the rear end portion side and the rear bent portion 28 of the midway member 27. ) Protruding toward the inclination direction so as to gradually change to a protruding posture toward).

上記の場合、両外向きフランジ３５，３５の突出姿勢の変化は上記前部屈曲部２６と後部屈曲部２８とのそれぞれにおいてほぼ完結するよう急変させられているが、図４中一点鎖線で示すように、上記両外向きフランジ３５，３５の突出姿勢の変化は緩やかになされるようにしてもよい。 In the above case, the change in the projecting posture of both outward flanges 35, 35 is suddenly changed so as to be almost completed in each of the front bent portion 26 and the rear bent portion 28, but this is indicated by a one-dot chain line in FIG. As described above, the projecting posture of the outward flanges 35, 35 may be changed gradually.

一方、上記両他の外向きフランジ３６，３６は、サイドメンバ１２の長手方向の各部においてそれぞれ内、外側板材３３，３４から下方に向かって突出している。 On the other hand, the other outward flanges 36, 36 protrude downward from the inner and outer plate members 33, 34 at respective portions in the longitudinal direction of the side member 12.

上記膨出部１９の下方に中途部メンバ２７と前、後部屈曲部２６，２８とがそれぞれ位置させられている。これにより、これら中途部メンバ２７と前、後部屈曲部２６，２８とから上方に突出した上記両外向きフランジ３５，３５は上記膨出部１９の内部空間１７に収容される。 A midway member 27 and front and rear bent portions 26 and 28 are respectively positioned below the bulging portion 19. Accordingly, the outward flanges 35 and 35 protruding upward from the midway member 27 and the front and rear bent portions 26 and 28 are accommodated in the internal space 17 of the bulging portion 19.

なお、以上は図示の例によるが、上記サイドメンバ１２の構成はキャブオーバ型ワンボックスの自動車にも適用可能である。 In addition, although the above is based on the example of illustration, the structure of the said side member 12 is applicable also to the vehicle of a cab over type one box.

また、上記サイドメンバ１２における前部屈曲部２６と後部屈曲部２８との屈曲方向は、車体２の幅方向で上記したものとはそれぞれ逆にしてもよく、この場合、上記一側方は車体２の内側方となり、上記他側方は外側方となる。 Further, the bending direction of the front bent portion 26 and the rear bent portion 28 in the side member 12 may be opposite to that described above in the width direction of the vehicle body 2, and in this case, the one side is the vehicle body side. 2 is the inner side, and the other side is the outer side.

具体的には、上記前部屈曲部２６では外側板材３４よりも内側板材３３の屈曲半径が小さくなることとされ、この内側板材３３が上記他側方（外側方）に向かって開く断面コの字形状とされる。また、上記後部屈曲部２８では内側板材３３よりも外側板材３４の屈曲半径が小さくなることとされ、この外側板材３４が上記一側方（内側方）に向かって開く断面コの字形状とされる。 Specifically, the bending radius of the inner plate member 33 is smaller than that of the outer plate member 34 at the front bent portion 26, and the inner plate member 33 has a cross-sectional shape that opens toward the other side (outer side). It is shaped like a letter. Further, at the rear bent portion 28, the bending radius of the outer plate member 34 is smaller than that of the inner plate member 33, and the outer plate member 34 has a U-shaped cross section that opens toward the one side (inner side). The

ここで、走行中の車両１の前突時には、前記従来の技術にて説明のように、前、後部屈曲部２６，２８における元の屈曲状態が上記前突による衝撃力Ｆにより更に進行するよう屈曲させられがちとなる（図３中一点鎖線図示）。この結果、前突時には、上記サイドメンバ１２は上記前、後部屈曲部２６，２８を起点として直ちに容易に座屈するおそれを生じる。 Here, at the time of the frontal collision of the traveling vehicle 1, the original bent state at the front and rear bent portions 26 and 28 is further advanced by the impact force F due to the frontal collision as described in the prior art. It tends to be bent (shown by a one-dot chain line in FIG. 3). As a result, at the time of a front collision, the side member 12 may be easily buckled immediately starting from the front and rear bent portions 26 and 28.

しかし、上記構成によれば、前部屈曲部２６における上記内、外側板材３３，３４のうちの上記一側方に位置する板材を車体２の他側方に向かって開く断面コの字形状とし、上記後部屈曲部２８における上記内、外側板材３３，３４のうちの上記他側方に位置する板材を上記一側方に向かって開く断面コの字形状としている。 However, according to the above configuration, the plate material positioned on the one side of the inner and outer plate members 33 and 34 in the front bent portion 26 has a U-shaped cross section that opens toward the other side of the vehicle body 2. The plate material located on the other side of the inner and outer plate members 33 and 34 in the rear bent portion 28 has a U-shaped cross section that opens toward the one side.

このため、前突時の衝撃力Ｆにより、上記サイドメンバ１２の前、後部屈曲部２６，２８において、より大きい圧縮応力が集中しがちとなる屈曲半径が小さい側の上記前部屈曲部２６での外側板材３４もしくは内側板材３３（図例では外側板材３４）と、上記後部屈曲部２８での内側板材３３もしくは外側板材３４（図例では内側板材３３）とは、それぞれ上記したように断面コの字形状であって、この断面コの字形状において２つの屈曲部が存在する側の底部が、上記した圧縮応力が集中しがちとなる側に位置することとされる。そして、上記した断面コの字形状の底部は、上記各屈曲部の断面がそれぞれアングル形状とされて上記サイドメンバ１２の長手方向に向かって延びる二条の稜線を有しており、上記アングル形状はほぼ直角に屈曲した断面を有して剛性を大きくできるものである。このため、上記断面コの字形状の底部は、上記衝撃力Ｆを強固に支持し得る強度構造となっている。 For this reason, due to the impact force F at the time of the front impact, the front bending portion 26 on the side where the bending radius is small, where a larger compressive stress tends to concentrate at the front and rear bending portions 26 and 28 of the side member 12. The outer plate member 34 or inner plate member 33 (outer plate member 34 in the illustrated example) and the inner plate member 33 or outer plate member 34 (inner plate member 33 in the illustrated example) at the rear bent portion 28 are each of a cross-sectional shape as described above. In this U-shaped cross section, the bottom portion on the side where two bent portions exist is positioned on the side where the above-described compressive stress tends to concentrate. The bottom of the U-shaped cross-section described above has two ridges extending in the longitudinal direction of the side member 12 with the cross-sections of the bent portions being angle-shaped, and the angle shape is It has a cross section bent substantially at a right angle and can increase rigidity. For this reason, the U-shaped bottom portion of the cross section has a strength structure capable of firmly supporting the impact force F.

よって、上記前、後部屈曲部２６，２８における元の屈曲状態（図１，３，５中実線）が上記衝撃力Ｆにより更に進行するよう屈曲させられる（図３中一点鎖線）ことは防止され、つまり、上記サイドメンバ１２が上記前、後部屈曲部２６，２８を起点として容易に座屈することは防止される。この結果、前突時には、その衝撃力Ｆによりサイドメンバ１２の長手方向の各部がそれぞれ変形して上記衝撃力Ｆのエネルギーが効果的に吸収され、この衝撃力Ｆが効果的に緩和されると共に、車体２が無用に大きく変形することがより確実に防止される。 Therefore, it is prevented that the original bent state (the solid line in FIGS. 1, 3 and 5) at the front and rear bent portions 26 and 28 is bent so as to further progress by the impact force F (the chain line in FIG. 3). That is, the side member 12 is prevented from easily buckling starting from the front and rear bent portions 26 and 28. As a result, at the time of the front collision, the impact force F deforms each part in the longitudinal direction of the side member 12 to effectively absorb the energy of the impact force F, and the impact force F is effectively reduced. In addition, the vehicle body 2 is more reliably prevented from being unnecessarily greatly deformed.

また、上記中途部メンバ２７における上記内、外側板材３３，３４の各下端部同士の接合部と上記両外向きフランジ３５，３５同士の接合部とが、上記中途部メンバ２７の前部側から後部側に向かうに従いこの中途部メンバ２７における上記他側方の側部がわから上記一側方の側部がわに向けて漸次変位するようにしている。 Further, the joining portion between the lower end portions of the inner and outer plate members 33 and 34 and the joining portion between the two outward flanges 35 and 35 in the midway member 27 from the front side of the midway member 27. The other side portion of the midway member 27 is gradually displaced from the side toward the rear side toward the rear side.

このため、上記中途部メンバ２７の長手方向各部における断面係数は緩やかに変化して、剛性上の断点が生じないことから、上記衝撃力Ｆによりサイドメンバ１２の中途部メンバ２７が容易に座屈することも、より確実に防止される。 For this reason, since the section modulus of each part in the longitudinal direction of the midway member 27 changes gently and no stiff point is generated, the midway member 27 of the side member 12 can be easily seated by the impact force F. Bending is also more reliably prevented.

また、上記した前突時におけるサイドメンバ１２の座屈防止は、このサイドメンバ１２が元来有する内、外側板材３３，３４や両外向きフランジ３５，３５の形状を工夫することにより達成される。よって、上記サイドメンバ１２の座屈防止は、車体２の構成部品の増加や車体２の質量の増加を抑制しつつ達成でき、車体２の生産性が良好に維持される。 Further, the buckling of the side member 12 at the time of the above-described front collision is achieved by devising the shapes of the inner side plates 33 and 34 and the outward flanges 35 and 35 that the side member 12 originally has. . Therefore, the buckling prevention of the side member 12 can be achieved while suppressing an increase in the number of components of the vehicle body 2 and an increase in the mass of the vehicle body 2, and the productivity of the vehicle body 2 is maintained well.

しかも、上記膨出部１９の下方に上記中途部メンバ２７と前、後部屈曲部２６，２８とをそれぞれ位置させている。 Moreover, the midway member 27 and the front and rear bent portions 26 and 28 are positioned below the bulging portion 19.

このため、上記中途部メンバ２７から外方に突出する両外向きフランジ３５，３５は上記膨出部１９の内部空間１７に収容させることができて、上記両外向きフランジ３５，３５が他のものと干渉し合うことは防止される。よって、上記両外向きフランジ３５，３５の突出方向や幅方向の大きさを所望のものにできることから、その分、上記サイドメンバ１２の強度と剛性とを、より向上させることができ、前突時におけるこのサイドメンバ１２の座屈を更に確実に防止できる。 For this reason, both outward flanges 35 and 35 projecting outward from the midway member 27 can be accommodated in the internal space 17 of the bulging portion 19, and the both outward flanges 35 and 35 can be accommodated in the other spaces. Interference with things is prevented. Therefore, since the projecting direction and the width direction of the outward flanges 35, 35 can be made as desired, the strength and rigidity of the side member 12 can be further improved accordingly, The buckling of the side member 12 at the time can be further reliably prevented.

また、上記したように、サイドメンバ１２の両外向きフランジ３５，３５は上記膨出部１９の内部空間１７に収容されることから上記サイドメンバ１２とフロアパネル１６とが互いに干渉することは防止される。よって、これらサイドメンバ１２やフロアパネル１６の組み付けは、互いの干渉を避けつつ容易にすることができて、車体２の生産性が更に良好に維持される。 Further, as described above, since both the outward flanges 35, 35 of the side member 12 are accommodated in the internal space 17 of the bulging portion 19, the side member 12 and the floor panel 16 are prevented from interfering with each other. Is done. Therefore, the assembly of the side members 12 and the floor panel 16 can be facilitated while avoiding mutual interference, and the productivity of the vehicle body 2 can be maintained better.

１車両
２車体
３車体フレーム
４運転室
５運転台
１２サイドメンバ
１６フロアパネル
１７内部空間
１８エンジン
１９膨出部
２５前部メンバ
２６前部屈曲部
２７中途部メンバ
２８後部屈曲部
２９後部メンバ
３３内側板材
３４外側板材
３５外向きフランジ
３６他の外向きフランジ
Ｆ衝撃力 DESCRIPTION OF SYMBOLS 1 Vehicle 2 Car body 3 Car body frame 4 Driver's cab 5 Driver's cab 12 Side member 16 Floor panel 17 Internal space 18 Engine 19 Bulging part 25 Front member 26 Front bent part 27 Midway member 28 Rear bent part 29 Rear member 33 Inside Plate material 34 Outer plate material 35 Outward flange 36 Other outward flange F Impact force

Claims

車体の幅方向で互いに離れて位置する左右一対のサイドメンバと、これら左右サイドメンバ上に支持されるフロアパネルと、このフロアパネルの前後方向の中途部を上方に膨出させて形成され、その内部空間にエンジンを収容する膨出部とを備え、
上記サイドメンバが、その前部を構成して車体の前後方向に延びる前部メンバと、この前部メンバの後端部から前部屈曲部を経て後方かつ車体の一側方に向かって延びる中途部メンバと、この中途部メンバの後端部から後部屈曲部を経て車体の前後方向に延びる後部メンバとを有し、かつ、上記サイドメンバが、車体の幅方向で互いに対面して各下端縁部が互いに接合される内、外側板材と、これら内、外側板材の各上端縁部からそれぞれその外方に向かい突出して互いに接合される外向きフランジとを有した車両の車体下部構造において、
上記前部屈曲部における上記内、外側板材のうちの上記一側方に位置する板材を車体の他側方に向かって開く断面コの字形状とし、上記後部屈曲部における上記内、外側板材のうちの上記他側方に位置する板材を上記一側方に向かって開く断面コの字形状とし、
上記中途部メンバにおける上記内、外側板材の各下端部同士の接合部と上記両外向きフランジ同士の接合部とが、上記中途部メンバの前部側から後部側に向かうに従いこの中途部メンバにおける上記他側方の側部がわから上記一側方の側部がわに向けて漸次変位するようにし、
上記膨出部の下方に上記中途部メンバと前、後部屈曲部とをそれぞれ位置させたことを特徴とする車両の車体下部構造。 A pair of left and right side members positioned away from each other in the width direction of the vehicle body, a floor panel supported on the left and right side members, and a midway part in the front-rear direction of the floor panel are formed to bulge upward, A bulging portion for accommodating the engine in the internal space,
The side member constitutes a front part of the front member that extends in the front-rear direction of the vehicle body, and the middle extends from the rear end portion of the front member through the front bent portion and toward one side of the vehicle body. And a rear member extending in the front-rear direction of the vehicle body from the rear end portion of the midway member through the rear bent portion, and the side members face each other in the width direction of the vehicle body, and each bottom edge In the vehicle body lower part structure of the vehicle having outer plate members that are joined to each other, and outward flanges that project outward from the respective upper edge portions of the inner and outer plate members and are joined to each other.
Of the inner and outer plate members in the front bent portion, the plate member located on one side is formed into a U-shaped cross section that opens toward the other side of the vehicle body, and the inner and outer plate members in the rear bent portion are formed. The plate material located on the other side of the above is a U-shaped cross section that opens toward the one side,
In the midway member, the joints between the lower ends of the inner and outer plate members and the joints between the two outward flanges move from the front side to the rear side of the midway member. The other side part is gradually displaced from the side to the one side part,
A vehicle body lower part structure for a vehicle, wherein the midway member and the front and rear bent parts are respectively positioned below the bulging part.