VEHICLE-BODY LOWER STRUCTURE OF VEHICLE

A side sill that is disposed in a lower part and on an outer side in a vehicle width direction of a vehicle and has a side sill inner and a side sill outer which collaborate with each other to form a closed cross section extending in a front-rear direction of the vehicle; a wheel that is located ahead of the side sill outer; an outer-side reinforcement member that has a shape extending along a front face part and a side face part in a front end part of the side sill outer and is joined to the front end part from inside the closed cross section; and an inner-side reinforcement member that diagonally couples a front face part and a side face part in a front end part of the side sill inner to each other.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Japanese Patent Application 2022-083945, filed May 23, 2022, the entire contents of which are incorporated herein by reference.

BACKGROUND

Field

The present disclosure relates to a vehicle-body lower structure of a vehicle including, for example: a side sill that forms a closed cross section extending in a front-rear direction of a vehicle on an outer side in a vehicle width direction; and a wheel that is located ahead of the side sill.

Description of the Related Art

Typically, at the time of so-called a small overlap collision in which a barrier partially collides, from ahead of a vehicle, with a front face of the vehicle at an end part located outward of a front side frame in the vehicle width direction, a wheel pulled back collides with a side sill front end part, and thus a collision load directed rearward and inward in the width direction is input to the side sill front end part.

The side sill front end part preferably can generate a reaction force in the vehicle width direction, which is large enough to bounce the wheel back outward for example, against the collision load directed inward in the width direction and input by the wheel, which enables a vehicle body to evade the barrier in the vehicle width direction by turning itself, for example, and thus makes it possible to inhibit the vehicle body from being reinforced excessively.

Meanwhile, the vehicle side structure of Patent document 1 is proposed as a configuration including a reinforcement member that reinforces a side sill front end part against a small overlap collision.

The vehicle side structure of Patent document 1 is provided, on an inner face in the vehicle width direction of a side sill outer front end part located on the outer side in the vehicle width direction of a side sill front end part, with an outer-side reinforcement member (30) that reinforces at least a front face and an outer face in the vehicle width direction of the side sill outer front end part.

However, even if provided with the outer-side reinforcement member (30) on the inner face in the vehicle width direction, the side sill outer may be displaced inward in the vehicle width direction together with the outer-side reinforcement member (30) when a load directed inward in the width direction is input to the side sill front end part, so that an intended reaction force in the width direction may not be able to be achieved.

PRIOR ART DOCUMENTS

Patent Documents

SUMMARY

The present disclosure has been made in view of such a problem, and aims to provide a vehicle-body lower structure of a vehicle capable of inhibiting a side sill front end part from getting crushed and achieving a reaction force in a vehicle width direction against a collision load directed inward in the vehicle width direction and input to the side sill front end part at the time of a small overlap collision.

Means for Solving the Problem

A vehicle-body lower structure of a vehicle according to the present disclosure includes: a side sill that is disposed in a lower part and on an outer side in a vehicle width direction of a vehicle and has a side sill inner located on an inner side in the vehicle width direction and a side sill outer located on the outer side in the vehicle width direction, the side sill inner and the side sill outer collaborating with each other to form a closed cross section that extends in a front-rear direction of the vehicle; a wheel that is located ahead of the side sill outer; an outer-side reinforcement member that has a shape extending along a front face part and a side face part in a front end part of the side sill outer and is joined to the front end part from the closed cross section side; and an inner-side reinforcement member that diagonally couples a front face part and a side face part in a front end part of the side sill inner to each other.

According to the above configuration, when a collision load directed inward in the vehicle width direction is input to the side sill front end part, the side sill outer front end part tries to be displaced inward in the vehicle width direction with its shape kept by the outer-side reinforcement member.

Thereby, a load directed inward in the vehicle width direction is input to the side sill inner front end part by the side sill outer front end part. Since the inner-side reinforcement member can inhibit the part between the front face part and the side face part of the side sill inner front end part from being bent and deformed by the input of the load directed inward in the vehicle width direction, it is possible to inhibit the side sill front end part from getting crushed and deformed inward in the vehicle width direction and generate a reaction force in the vehicle width direction.

Accordingly, it is possible to make the vehicle body evade a barrier in the vehicle width direction, and thus inhibit the vehicle body from being reinforced excessively.

As an aspect of the present disclosure, it is preferable that an inner vertical ridge line that extends in a vertical direction is formed in a boundary part between the front face part and the side face part of the front end part of the side sill inner, and a portion of the inner-side reinforcement member that straddles the inner vertical ridge line in a direction in which the inner-side reinforcement member extends is provided so as to be located away from the inner vertical ridge line toward the inner side of the closed cross section.

According to the above configuration, it is possible to efficiently inhibit the inner vertical ridge line from being bent and deformed while suppressing a weight increase of the inner-side reinforcement member provided between the front face part and the side face part of the front end part of the side sill inner.

As another aspect of the present disclosure, it is preferable that the portion of the inner-side reinforcement member that straddles the inner vertical ridge line in the direction in which the inner-side reinforcement member extends has a bead that protrudes to the inner side or the outer side of the closed cross section.

According to the above configuration, it is possible to enhance the bending rigidity of the portion of the inner-side reinforcement member that straddles the inner vertical ridge line in the direction in which the inner-side reinforcement member extends, and further inhibit the inner vertical ridge line of the front end part of the side sill inner from being bent and deformed.

As still another aspect of the present disclosure, it is preferable that the bead extends continuously at least over the portion of the inner-side reinforcement member that straddles the inner vertical ridge line in the direction in which the inner-side reinforcement member extends.

According to the above configuration, it is possible to enhance the bending rigidity of the inner-side reinforcement member, and further inhibit the inner vertical ridge line from being bent and deformed.

As still another aspect of the present disclosure, it is preferable that the outer-side reinforcement member has a protrusion part, which protrudes inward in the closed cross section, at the same height position as the bead of the inner-side reinforcement member and at a position coinciding with the bead in the front-rear direction.

According to the above configuration, at the time of input of a collision load directed inward in the vehicle width direction and input to the side sill front end part, depending on its input mode, it is possible to cause the protrusion part of the outer-side reinforcement member displaced inward in the vehicle width direction to come into contact with the bead of the inner-side reinforcement member from the outer side in the vehicle width direction.

Thus, a load transmission part extends continuously to the inner side in the vehicle width direction between the outer-side reinforcement member and the inner-side reinforcement member, which helps transmission of the load to the inner side in the vehicle width direction.

As still another aspect of the present disclosure, it is preferable that the inner-side reinforcement member is formed to have higher strength than the outer-side reinforcement member.

According to the above configuration, the inner-side reinforcement member, which has relatively high strength, receives and supports the outer-side reinforcement member that is displaced inward in the vehicle width direction at the time of input of a collision load directed inward in the vehicle width direction, whereby the collision load directed inward in the vehicle width direction can be received effectively.

As still another aspect of the present disclosure, it is preferable that the vehicle-body lower structure of a vehicle further includes an inner lateral ridge line reinforcement member that reinforces an inner lateral ridge line extending in the front-rear direction along a boundary part between an upper face part and the side face part of the side sill inner, and the inner lateral ridge line reinforcement member extends in the front-rear direction along the inner lateral ridge line and is provided at a position overlapping with the inner-side reinforcement member in the front-rear direction.

According to the above configuration, for example, when a rearward collision load is input to the side sill front end part due to a small overlap collision, the collision load having been input to the inner-side reinforcement member can be transmitted to the rear side of the vehicle efficiently by the inner lateral ridge line reinforcement member.

Advantages

According to the above configuration, it is possible to inhibit a side sill front end part from getting crushed and achieve a reaction force in a vehicle width direction against a collision load directed inward in the vehicle width direction and input to the side sill front end part at the time of a small overlap collision.

DETAILED DESCRIPTION

Hereinbelow, an embodiment of the present disclosure will be described in detail based on the drawings.

Note that, since a vehicle-body lower structure1of a vehicle according to this embodiment is substantially symmetric, a description will be made based on a right-side vehicle lower structure. In the drawings, an arrow F indicates a front side of the vehicle, an arrow U indicates an upper side of the vehicle, an arrow OUT indicates an outer side in a vehicle width direction (vehicle exterior side), and an arrow IN indicates an inner side in the vehicle width direction (vehicle interior side). In addition, in the drawings, a mark “X” indicates a spot welding part.

As illustrated inFIGS.1and2, the vehicle-body lower structure1of this embodiment is provided with a tunnel part2that protrudes upward and extends in a front-rear direction at the center in the vehicle width direction of a bottom face of a vehicle interior. A platy floor panel3(seeFIG.1) forming a floor face of the vehicle interior is disposed horizontally on the bottom face of the vehicle interior at each of right and left sides of the tunnel part2. Each of right and left end parts of the bottom face of the vehicle interior includes a side sill10that extends in the front-rear direction. The floor panel3on each of the right and left sides has an outer end part in the vehicle width direction that is joined to an inner face in the vehicle width direction of the corresponding one of the right and left side sills10. Note that, as illustrated inFIG.1, the floor panel3is provided with a floor frame4that extends in the front-rear direction and a cross member5that extends in the vehicle width direction.

As illustrated inFIGS.1and2, the vehicle body is provided with a wheel6as a front wheel at a position ahead of the side sill10. The wheel6is disposed ahead of a front end of the side sill10and disposed at a position coinciding at least partially with the side sill10in the vehicle width direction.

As illustrated inFIG.1, in this embodiment, the wheel6has an inner end in the vehicle width direction that is disposed outward in the vehicle width direction of an inner end in the vehicle width direction of the side sill10, and the wheel is disposed closer to the outer side in the vehicle width direction than the side sill10. Note that more than half of an upper side of the wheel6is covered with an arch-shaped wheel house.

A lower part of a hinge pillar7that extends in a vertical direction along a front edge of a side door opening of the vehicle interior is joined to a front part of the side sill10(see the hinge pillar7illustrated by a virtual line inFIG.2). Note that, the lower part of the hinge pillar7, that is, a base part of the hinge pillar to be joined to the front part of the side sill10is formed in such a way that its width in the front-rear direction becomes wider as it goes downward.

The hinge pillar7includes a hinge pillar inner that is disposed on the inner side in the vehicle width direction and a hinge pillar outer7athat is disposed on the outer side in the vehicle width direction. By joining and securing both members to each other, the hinge pillar forms, in its inner part, a closed cross section that extends continuously in the vertical direction.

As illustrated inFIGS.1to8, the side sill10includes a side sill inner11that has a hat-shaped cross section open outward in the vehicle width direction and a side sill outer21that has a hat-shaped cross section open inward in the vehicle width direction. As illustrated inFIGS.3to8, by the side sill inner11located on the inner side in the vehicle width direction and the side sill outer21located on the outer side in the vehicle width direction collaborating with each other, the side sill10forms, in its inner part, a closed cross section10sthat extends continuously in the front-rear direction.

Specifically, as illustrated inFIGS.6and8, the side sill inner11includes: an inner-side upper face part12that extends substantially horizontally; an upper-end flange part13that extends upward from an outer edge of the inner-side upper face part12in the vehicle width direction; an inner-side side face part14that extends downward from an inner edge of the inner-side upper face part12in the vehicle width direction; an inner-side lower wall part15that extends outward in the vehicle width direction from a lower edge of the inner-side side face part14; and a lower-end flange part16that extends downward from an outer edge of the inner-side lower wall part15in the vehicle width direction.

As illustrated inFIGS.4and8, the side sill outer21includes: an outer-side upper face part22that extends substantially horizontally; an upper-end flange part23that extends upward from an outer edge of the outer-side upper face part22in the vehicle width direction; an outer-side side face part24that extends downward from the outer edge of the outer-side upper face part22in the vehicle width direction; an outer-side lower wall part25that extends inward in the vehicle width direction from a lower edge of the outer-side side face part24; and a lower-end flange part26that extends downward from an inner edge of the outer-side lower wall part25in the vehicle width direction.

As illustrated inFIG.8, by the upper-end flange parts13and23of the side sill inner11and the side sill outer21joined to each other by welding or the like and the lower-end flange parts16and26thereof joined to each other by welding or the like in a cross-sectional view taken along a plane orthogonal to a longitudinal direction, the side sill forms the closed cross section10sdescribed above in its inner part.

As illustrated inFIGS.1to6, the side sill10described above includes a side sill front end part31that extends rearward from the front end of the side sill10and a side sill main body part41that is substantially wholly disposed behind a rear end of the side sill front end part31. As illustrated inFIG.2, a boundary part between the side sill front end part31and the side sill main body part41corresponds to a position in the longitudinal width of the hinge pillar7, and to a substantially intermediate position in the front-rear direction of the hinge pillar7in this example.

As illustrated inFIGS.1to5andFIG.9, the side sill outer21includes a side sill outer front end part27and a side sill outer main body part28. As illustrated inFIGS.1,3,5,6, and9, the side sill inner11includes a side sill inner front end part17and a side sill inner main body part18. The side sill front end part31is formed by the side sill outer front end part27and the side sill inner front end part17, and the side sill main body part41is formed by the side sill outer main body part28and the side sill inner main body part18.

As illustrated inFIGS.3to5, in a boundary part between the side sill outer front end part27and the side sill outer main body part28, a rear-end flange32of the side sill outer front end part27and a front-end flange42of the side sill outer main body part28are joined to each other by spot welding or the like while overlapping with each other in a thickness direction. In this embodiment, the rear-end flange32of the side sill outer front end part27is joined to the front-end flange42of the side sill outer main body part28from outside (the outer side in the vehicle width direction of) the closed cross section10s.

Note that, in this embodiment, although the side sill outer21is formed of at least two members constituted of the side sill outer front end part27and the side sill outer main body part28as illustrated inFIGS.1to5, the side sill outer may be formed of a single member that is continuous in the front-rear direction including the boundary part of these parts.

On the other hand, in the side sill inner11, although the side sill inner front end part17and the side sill inner main body part18are not formed of separate members but formed of a single member as illustrated inFIGS.1,3,5, and6, these parts may be formed of separate members as front and rear side areas separated by their boundary part.

As illustrated inFIG.1,FIGS.3to5, andFIG.9, the side sill outer front end part27includes an outer front face part271that forms a front wall of the side sill outer21and an outer front end rear part272that is located behind the outer front face part271.

As described previously, the outer front face part271and the outer front end rear part272are formed in a hat shape in cross section open inward in the vehicle width direction (seeFIGS.4and8). However, as illustrated inFIG.4, the outer front face part271is formed in a bowl shape that is gradually reduced in diameter in the vertical direction and the vehicle width direction from a front end of the outer front end rear part272toward the front.

Specifically, as illustrated inFIG.4, as in the outer front end rear part272, the outer front face part271has the outer-side upper face part22, the upper-end flange part23, the outer-side side face part24, the outer-side lower wall part25, and the lower-end flange part26. However, as illustrated inFIG.1,FIGS.3to5, andFIGS.7and9, the outer-side side face part24of the outer front face part271gently inclines from a front end of the outer-side side face part24of the outer front end rear part272to an inner end in the vehicle width direction of the side sill outer21as it extends forward.

As illustrated inFIGS.2and4, the outer-side upper face part22and the outer-side lower wall part25of the outer front face part271gently incline from front ends of the outer-side upper face part22and the outer-side lower wall part25of the outer front end rear part272to the vicinity of an intermediate part in the vertical direction of the side sill outer21as they extend forward.

In addition, as illustrated inFIGS.4,7, and9, the side sill outer front end part27extends smoothly in the front-rear direction while a ridge line extending in the vertical direction along a boundary part between a rear end of the outer front face part271and the front end of the outer front end rear part272is not formed in the boundary part.

Note that, in this embodiment, the side sill outer front end part27includes the outer front face part271and the outer front end rear part272; however, not being limited thereto, the side sill outer front end part27does not necessarily have to include the outer front end rear part272and may be formed only of the outer front face part271that is gradually reduced in diameter from a front end42f(seeFIGS.4and9) of the side sill outer main body part28toward the front.

In addition, as described previously, the side sill outer main body part28is formed in a hat shape in cross section open inward in the vehicle width direction as described above (seeFIG.4).

As illustrated inFIGS.3,4, and9, an outer-side protrusion part43that protrudes inward in the vehicle width direction from its periphery is provided at a substantially intermediate position in the vertical direction of the outer-side side face part24of the side sill outer main body part28. The outer-side protrusion part43extends continuously rearward from the front end42fof the side sill outer main body part28.

As illustrated inFIG.4, in the outer-side side face part24of the side sill outer main body part28, the outer-side protrusion part43has: an upper wall part44that stands inward in the vehicle width direction (to the inner side of the closed cross section10s) from its periphery; a vertical wall part45that extends downward in a vertical wall shape from an inner end in the vehicle width direction of the upper wall part44; and a lower wall part46that stands inward in the vehicle width direction from its periphery to a lower end of the vertical wall part45.

In a boundary part between the vertical wall part45and the upper wall part44of the outer-side protrusion part43, an upper-side lateral ridge line47that extends continuously rearward from the front end42fof the outer-side protrusion part43along this boundary part. In addition, in a boundary part between the vertical wall part45and the lower wall part46of the outer-side protrusion part43, a protrusion part lower-side lateral ridge line48that extends continuously rearward from the front end42fof the outer-side protrusion part43along this boundary part.

In addition, as illustrated inFIG.3,FIGS.5to7, andFIG.9, the side sill inner front end part17includes an inner front face part171that forms a front wall of the side sill inner11; and an inner front end rear part172that is located behind the inner front face part171.

As illustrated inFIG.6, the side sill inner11is formed in such a way that, while the inner front face part171is formed in a vertical wall shape extending in the vehicle width direction and the vertical direction, an area extending across the inner front end rear part172and the side sill inner main body part18(seeFIG.9) is formed in a hat shape in cross section open outward in the vehicle width direction as described above.

Specifically, the side sill inner11has a configuration such that the inner-side upper face part12extends continuously rearward from an upper end of the inner front face part171, the inner-side side face part14extends continuously rearward from an inner end in the vehicle width direction of the inner front face part171, and the inner-side lower wall part15extends continuously rearward from a lower end of the inner front face part171, respectively.

As illustrated inFIGS.5,6, and9, in a boundary part between the inner front face part171and the inner-side side face part14, an inner vertical ridge line141is formed so as to extend in the vertical direction along this boundary part. Note that, in this embodiment, the inner front face part171and the inner front end rear part172are formed by separate members, and are joined to each other by welding or the like with their end parts overlapping with each other in the thickness direction in their boundary part (seeFIGS.3,5, and6).

In addition, as illustrated inFIGS.6and8, an inner lateral ridge line142is formed in the side sill inner11so as to extend in the front-rear direction along a boundary part between the inner-side upper face part12and the inner-side side face part14.

Further, as illustrated inFIGS.3to7andFIG.9, front-end flange parts19and29that protrude forward are formed at an outer end in the vehicle width direction of the inner front face part171and an inner end in the vehicle width direction of the outer front face part271described above, respectively. The front-end flange parts19and29are joined to each other by welding or the like while overlapping with each other in the vehicle width direction.

As illustrated inFIGS.3to5andFIGS.7to9, the side sill outer front end part27includes an outer-side reinforcement member50that reinforces the side sill outer front end part27. The outer-side reinforcement member50has a shape extending along the side sill outer front end part27.

Specifically, as illustrated in the drawings such asFIG.4, the outer-side reinforcement member50is formed in a bowl shape so as to correspond to the bowl-shaped side sill outer front end part27, and includes: an outer-side side face reinforcement part51that extends along the outer-side side face part24of the side sill outer front end part27; an outer-side lower wall reinforcement part52that extends along the outer-side lower wall part25; and an outer-side upper wall reinforcement part53that extends along the outer-side upper face part22.

The outer-side reinforcement member50is joined to the side sill outer front end part27by welding or the like from inside the closed cross section10sof the side sill10so as to be substantially wholly superimposed on the side sill outer front end part.

As illustrated in the drawings such asFIG.4, the outer-side reinforcement member50is formed so as to extend over substantially the entire length in the front-rear direction of the side sill outer front end part27excluding the front-end flange part29, and its rear end54is substantially wholly located ahead of the front end42fof the side sill outer main body part28.

As illustrated inFIG.3andFIGS.5to9, the side sill inner11includes an inner-side reinforcement member60and an inner lateral ridge line reinforcement member70(seeFIGS.3,5,6, and8).

The inner-side reinforcement member60is provided in the side sill inner front end part17and reinforces the side sill inner front end part17. The inner-side reinforcement member60is joined to the inner front face part171and the inner-side side face part14of the inner front end rear part172in the side sill inner front end part17from inside the closed cross section10sof the side sill10so as to diagonally couple them to each other.

Specifically, as illustrated in the drawings such asFIGS.5to9, the inner-side reinforcement member60includes: an inner-side reinforcement member front part61that extends horizontally in the vehicle width direction so as to be capable of being joined to the inner front face part171; an inner-side reinforcement member side face part62that extends horizontally in the front-rear direction so as to be capable of being joined to the inner-side side face part14; and a diagonal part63that extends horizontally from a front end of the inner-side reinforcement member side face part62to an inner end in the vehicle width direction of the inner-side reinforcement member front part61so as to incline outward in the vehicle width direction as it extends forward. A portion of the inner-side reinforcement member60that straddles the inner vertical ridge line141in a direction in which the inner-side reinforcement member extends, that is, the diagonal part63is provided so as to be located away from the inner vertical ridge line141toward the inner side of the closed cross section10s.

In this embodiment, the inner-side reinforcement member60is disposed at the same height position as the outer-side reinforcement member50and at a position coinciding with the outer-side reinforcement member in the front-rear direction. Thus, the inner-side reinforcement member60and the outer-side reinforcement member50are opposed to each other with the closed cross section10sinterposed in between.

A bead64that protrudes inward in the vehicle width direction is provided at an intermediate position in the vertical direction of the inner-side reinforcement member60. As illustrated inFIGS.5,6, and9, the bead64is formed so as to extend continuously over a part in the direction in which the inner-side reinforcement member60extends, at least over the diagonal part63, and in this example, extend continuously over the entire length of the inner-side reinforcement member in the direction in which it extends.

Note that,FIG.9is a horizontal cross-sectional view of the side sill front end part31taken at the level of the bead64.

The inner-side reinforcement member60is formed to have a higher strength than the outer-side reinforcement member50.

In this example, the inner-side reinforcement member60and the outer-side reinforcement member50are both formed of an ultra-high-tensile steel plate, and the inner-side reinforcement member60is formed of a material having a higher strength than the outer-side reinforcement member50in such a way that the outer-side reinforcement member50has a tensile strength of approximately590MPa while the inner-side reinforcement member60has a tensile strength of approximately980MPa. In addition, the inner-side reinforcement member60is formed to be thicker than the outer-side reinforcement member50in such a way that the outer-side reinforcement member50has a thickness of approximately 2.0 mm while the inner-side reinforcement member60has a thickness of approximately 2.3 mm.

Note that, although the inner-side reinforcement member60is formed of a material having a higher strength than the outer-side reinforcement member50and formed to be thicker than the outer-side reinforcement member in this example, the present disclosure is not limited to this. For example, the inner-side reinforcement member60may be formed to have a higher strength than the outer-side reinforcement member50in such a way that the inner-side reinforcement member60is formed to be thicker than the outer-side reinforcement member50while both of them are formed of a material of the same strength, or in such a way that the inner-side reinforcement member60is formed of a material having a higher strength than the outer-side reinforcement member50while both of them are formed to have the same thickness.

In addition, as illustrated in the drawings such asFIGS.6and8, the inner lateral ridge line reinforcement member70described above extends along the inner lateral ridge line142located in the boundary part between the inner-side upper face part12and the inner-side side face part14. Further, the inner lateral ridge line reinforcement member70includes an inner-side reinforcement upper wall71and an inner-side reinforcement vertical face72, and is formed so that its cross section taken along the plane orthogonal to the longitudinal direction, in which an inner end in the vehicle width direction of the inner-side reinforcement upper wall71and an upper end of the inner-side reinforcement vertical face72are formed integrally, has an L shape. The inner lateral ridge line reinforcement member70extends linearly and continuously from the vicinity of the inner front face part171of the side sill inner11to a position behind at least a rear end of the side sill inner front end part17. Thus, as illustrated inFIGS.5and6, a front part of the inner lateral ridge line reinforcement member70is provided at a position overlapping with the inner-side reinforcement member side face part62of the inner-side reinforcement member60in the front-rear direction.

By joining the inner-side reinforcement upper wall71to the inner-side upper face part12and joining the inner-side reinforcement vertical face72to the inner-side side face part14in a corner part between the inner-side upper face part12and the inner-side side face part14of the side sill inner11, the inner lateral ridge line reinforcement member70reinforces the inner lateral ridge line142located in the boundary part between the inner-side upper face part12and the inner-side side face part14.

In addition, as illustrated inFIGS.3and4andFIGS.7to9, a front-end protrusion part57that protrudes inward in the closed cross section10sis provided in a front part of the outer-side reinforcement member50described above. The front-end protrusion part57is provided in the outer-side reinforcement member50at the same height position as the bead64of the inner-side reinforcement member60and at a position coinciding with the bead in the front-rear direction.

The front-end protrusion part57extends in the vehicle width direction, and protrudes rearward relative to a rear face of the outer front face part271(inward in the closed cross section10s) so that an inner end in the vehicle width direction of the front-end protrusion part57is located at an inner end in the vehicle width direction of the outer-side reinforcement member50. The front-end protrusion part57is formed in such a way that it protrudes further rearward as it extends inward in the vehicle width direction so that a portion formed between itself and the rear face of the outer front face part271opens to the inner side in the vehicle width direction.

As illustrated inFIGS.1and2, the vehicle-body lower structure1of a vehicle of this embodiment described above includes the side sill10that is disposed in a lower part and on the outer side in the vehicle width direction of the vehicle and the wheel6that is located ahead of the side sill outer21.

By the side sill inner11located on the inner side in the vehicle width direction and the side sill outer21located on the outer side in the vehicle width direction collaborating with each other, the side sill10forms the closed cross section10sthat extends in the front-rear direction of the vehicle (seeFIG.3).

In addition, as illustrated inFIGS.3to5andFIGS.7to9, the vehicle-body lower structure1of a vehicle of this embodiment includes the outer-side reinforcement member50that is joined to the side sill outer front end part27(a front end part of the side sill outer21) from inside the closed cross section10s.The outer-side reinforcement member50has a shape extending along the outer front face part271(a front face part) of the side sill outer front end part27and the outer-side side face part24(a side face part).

Further, as illustrated inFIG.3andFIGS.5to9, the vehicle-body lower structure1of a vehicle of this embodiment includes the inner-side reinforcement member60that is joined to the side sill inner front end part17(a front end part of the side sill inner11) from inside the closed cross section10s.The inner-side reinforcement member60diagonally couples the inner front face part171(a front face part) of the side sill inner front end part17and the inner-side side face part14(a side face part) to each other.

The working effects of the vehicle-body lower structure1of a vehicle described above will be described usingFIGS.10A-10D.

FIGS.10A-10Dare cross-sectional views illustrating, based onFIG.9, a simulation analysis result of behaviors of the side sill front end part31observed when a collision load is input to the side sill front end part31at the time of a small overlap collision.

Note that,FIGS.10A-10Dillustrate, in the order of10A to10D, processes from a collision initial phase to a collision later phase in chronological order. Dots in this drawing indicate a stress distribution image, and a portion where dots are denser indicates higher stress (collision energy).

Once the wheel6pulled back at the time of the small overlap collision collides with the side sill front end part31, a collision load directed to the rear side of the vehicle and to the inner side thereof in the vehicle width direction is input to the side sill outer front end part27. In this embodiment, since the wheel6is disposed at a position closer to the outer side in the vehicle width direction than the side sill10(that is, the wheel has, what is called, a layout such that it protrudes outward relative to the side face of the vehicle body) (seeFIG.1), as illustrated in the stress distribution ofFIG.10A, the collision load from the wheel6is input mainly to the side sill outer front end part27of the side sill front end part31.

Here, since the side sill outer front end part27includes the outer-side reinforcement member50, as illustrated inFIG.10B, the side sill outer front end part is hardly crushed by the input of the collision load directed inward in the vehicle width direction and tries to be displaced inward in the vehicle width direction while substantially keeping its shape.

Meanwhile, a load directed inward in the vehicle width direction is input to the side sill inner front end part17by the side sill outer front end part27that tries to be displaced inward in the vehicle width direction. By such a load directed inward in the vehicle width direction, as illustrated inFIG.10C, the inner front face part171and the outer front face part271forming a front face of the side sill front end part31are deformed into an M shape in a plan view such that their central part in the vehicle width direction protrudes to the inner side of the closed cross section10s(rearward) relative to their both inner and outer sides in the vehicle width direction.

Here, since the side sill inner front end part17includes the inner-side reinforcement member60that diagonally couples the inner front face part171and the inner-side side face part14to each other, as illustrated inFIG.10D, it is possible to inhibit the inner vertical ridge line141from being bent and deformed by the load directed inward in the vehicle width direction and input by the side sill outer front end part27. Thus, a space Sa is secured in a corner portion between the inner front face part171and the inner-side side face part14. In other words, as illustrated inFIG.10D, the inner-side reinforcement member60can inhibit the side sill inner front end part17from being crushed and deformed in the vehicle width direction.

Accordingly, at the time of the small overlap collision, the side sill front end part31can generate a reaction force in the vehicle width direction, which is large enough to bounce the wheel6back outward for example, against the collision load directed inward in the width direction and input by the wheel6. As a consequence, at the time of the small overlap collision, the vehicle-body lower structure1of a vehicle of this embodiment enables the vehicle body to evade a barrier in the vehicle width direction, and thus can inhibit the vehicle body from being reinforced excessively.

As an aspect of the present disclosure, as illustrated inFIG.3andFIGS.5to9, the inner vertical ridge line141extending in the vertical direction is formed in the boundary part between the inner front face part171of the side sill inner front end part17and the inner-side side face part14, and as illustrated inFIGS.7and9, the diagonal part63of the inner-side reinforcement member60is provided so as to be located away from the inner vertical ridge line141toward the inner side of the closed cross section10s.

According to the above configuration, it is possible to efficiently inhibit the inner vertical ridge line141from being bent and deformed at the time of a small overlap collision while suppressing a weight increase of the inner-side reinforcement member60provided between the inner front face part171of the side sill inner front end part17and the inner-side side face part14.

As another aspect of the present disclosure, as illustrated inFIGS.5to9, a portion of the inner-side reinforcement member60in the direction in which the inner-side reinforcement member extends, at least the diagonal part63, has the bead64that protrudes to the inner side of the closed cross section10s(outward in the vehicle width direction and rearward), which makes it possible to enhance the bending rigidity of the part in the direction in which the inner-side reinforcement member60extends, especially the diagonal part63, and further inhibit the inner vertical ridge line141of the side sill inner front end part17from being bent and deformed.

As still another aspect of the present disclosure, as illustrated inFIGS.3and4andFIGS.7to9, the outer-side reinforcement member50has the front-end protrusion part57(a protrusion part), which protrudes inward in the closed cross section10s(rearward), at the same height position as the bead64of the inner-side reinforcement member60and at a position coinciding with the bead in the front-rear direction.

According to the above configuration, at the time of input of a collision load directed inward in the vehicle width direction and input to the side sill front end part31, depending on its input mode, it is possible to cause the front-end protrusion part57, which is included in the outer-side reinforcement member50displaced inward in the vehicle width direction, to engage with (come into contact with) the bead64of the inner-side reinforcement member60(for example, an inner end in the vehicle width direction of the bead64in the inner-side reinforcement member front part61) from the outer side in the vehicle width direction.

Thus, a load transmission part that extends continuously to the inner side in the vehicle width direction is formed between the outer-side reinforcement member50and the inner-side reinforcement member60, which helps transmission of the load to the inner side in the vehicle width direction.

As still another aspect of the present disclosure, the inner-side reinforcement member60is formed to have higher strength than the outer-side reinforcement member50.

According to the above configuration, the inner-side reinforcement member60, which has high strength relative to the outer-side reinforcement member50, receives and supports the outer-side reinforcement member50that is displaced inward in the vehicle width direction when a collision load directed inward in the vehicle width direction is input to the side sill front end part31, whereby the collision load directed inward in the vehicle width direction can be received effectively.

In addition, since the outer-side reinforcement member50is formed to have lower strength than the inner-side reinforcement member60, it is possible to suppress an increase in material cost and weight as compared to a case where both the outer-side reinforcement member50and the inner-side reinforcement member60are formed to have high strength.

As still another aspect of the present disclosure, as illustrated inFIGS.3,5,6, and8, the inner lateral ridge line reinforcement member70is provided so as to reinforce the inner lateral ridge line142(seeFIGS.6and8) extending in the front-rear direction along the boundary part between the inner-side upper face part12and the inner-side side face part14of the side sill inner11. As illustrated inFIGS.5and6, the inner lateral ridge line reinforcement member70extends in the front-rear direction along the inner lateral ridge line142and is provided at a position overlapping with the inner-side reinforcement member60in the front-rear direction.

According to the above configuration, when a rearward collision load is input to the side sill front end part31, the collision load directed to the rear side of the vehicle having been input to the inner-side reinforcement member60can be transmitted to the rear side of the vehicle efficiently by the inner lateral ridge line reinforcement member70.

The present disclosure is not limited only to the configuration of the above embodiment and can be formed by various embodiments.

DESCRIPTION OF REFERENCE SIGNS AND NUMERALS

1VEHICLE-BODY LOWER STRUCTURE OF VEHICLE6WHEEL10SIDE SILL10sCLOSED CROSS SECTION11SIDE SILL INNER12INNER-SIDE UPPER FACE PART (UPPER FACE PART OF SIDE SILL INNER)14INNER-SIDE SIDE FACE PART (SIDE FACE PART OF FRONT END PART OF SIDE SILL INNER, SIDE FACE PART OF SIDE SILL INNER)17SIDE SILL INNER FRONT END PART (FRONT END PART OF SIDE SILL INNER)21SIDE SILL OUTER24OUTER-SIDE SIDE FACE PART (SIDE FACE PART OF FRONT END PART OF SIDE SILL OUTER)27SIDE SILL OUTER FRONT END PART (FRONT END PART OF SIDE SILL OUTER)50OUTER-SIDE REINFORCEMENT MEMBER57FRONT-END PROTRUSION PART (PROTRUSION PART)60INNER-SIDE REINFORCEMENT MEMBER63DIAGONAL PART (PORTION STRADDLING INNER VERTICAL RIDGE LINE IN DIRECTION IN WHICH INNER-SIDE REINFORCEMENT MEMBER EXTENDS)64BEAD70INNER LATERAL RIDGE LINE REINFORCEMENT MEMBER141INNER VERTICAL RIDGE LINE142INNER LATERAL RIDGE LINE171INNER FRONT FACE PART (FRONT FACE PART OF FRONT END PART OF SIDE SILL INNER)271OUTER FRONT FACE PART (FRONT FACE PART OF FRONT END PART OF SIDE SILL OUTER)