JP2010228482A - Lower vehicle-body structure of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lower vehicle-body structure of a vehicle for restraining an intrusion quantity of a center pillar upper part by securing (-) of a center pillar lower part, by effectively absorbing compression input and bending force, while restraining buckling deformation of a cross member. <P>SOLUTION: A side sill side end part of the cross member 30 is arranged in a position at a predetermined interval from a side sill 6, and a joining member 35 is arranged for joining the side sill side end part of the cross member 30 and a side surface of the side sill 6. The joining member 35 is set in lower strength than the cross member 30, and strength of a cross member joining area C of the joining member 35 is constituted so as to become higher than strength of a side sill joining area S of the joining member 35. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle body lower part structure in which a cross member extending in a vehicle width direction is provided between a tunnel part at an upper part of a floor panel and a side sill to which a center pillar is coupled.

Conventionally, when the side sill to which the center pillar is coupled and the tunnel portion are completely coupled and fixed by a cross member extending in the vehicle width direction, the side sill is supported by the strong strength of the cross member when a side collision load is input. Therefore, there has been a problem that the upper part of the center pillar largely enters the vehicle interior, or the center portion in the vertical direction of the center pillar buckles, and the center pillar above the buckling point enters the vehicle interior.
In order to solve such a problem, as disclosed in Patent Document 1, in the cross member that joins between the side sill to which the center pillar is joined and the tunnel portion, the cross member in the vehicle width direction A hole is formed in the ridgeline part of the cross member with a cross-sectional hat shape in the part close to the outer side sill, and the cross-sectional yield strength of the connection part of the cross member to the side sill is set smaller than the cross-sectional yield strength of the cross member main body. Things have already been invented.

  In this conventional structure disclosed in Patent Document 1, when a side collision load is input, when the load is input to the cross member via the center pillar and the side sill, the cross member in which the hole is formed absorbs the load. While collapsing in the vehicle width direction, it is possible to absorb impact energy.

  Thereafter, when the center pillar receives a load, the upper side of the center pillar is displaced so as to incline into the vehicle interior, and a rotational moment acts on the side sill. The bending force of the rotational moment causes the cross member to buckle. Since it deforms, there is a problem that it cannot receive a load.

JP 2004-74835 A

  Therefore, the present invention provides a side sill side end portion of the cross member at a position spaced apart from the side sill, and a coupling member that connects the side sill side end portion of the cross member and the side surface of the side sill, The coupling member is set to have a lower strength than the cross member, and the strength of the cross member coupling region of the coupling member is set to be higher than the strength of the side sill coupling region of the coupling member. The side impact load is received in the side sill joint region where the strength of the joint member between the side sill and the cross member is low at the initial stage of input, and then the strength of the joint member against the bending moment from the side sill is increased. Ensure that the load is applied in the high crossmember coupling area and that the crossmember is strong enough to withstand their input. , While suppressing buckling deformation of the cross member, it can effectively absorb the compression input in the axial direction (vehicle width direction) and the bending input due to the bending moment, and also secure the deformation allowance under the center pillar An object of the present invention is to provide a lower body structure of a vehicle that can suppress the intrusion amount of the upper part of the center pillar.

A vehicle lower body structure according to the present invention is a vehicle lower body structure in which a cross member extending in the vehicle width direction is provided between a tunnel portion at an upper part of a floor panel and a side sill to which a center pillar is coupled, A side sill side end portion of the cross member is disposed at a position spaced apart from the side sill, and a coupling member for coupling the side sill side end portion of the cross member and the side surface of the side sill is provided, the coupling member Is set to be lower in strength than the cross member, and the strength of the cross member coupling region of the coupling member is higher than the strength of the side sill coupling region of the coupling member.
According to the above configuration, the side impact load input through the center pillar and the side sill receives the load in the side sill joint region where the strength of the joint member between the side sill and the cross member is low at the initial stage of input. The side sill joint region is crushed in the axial direction (vehicle width direction) while absorbing the load, and absorbs impact energy.

After that, the bending moment from the side sill receives a load in the cross member coupling region where the strength of the coupling member is high, and this cross member coupling region collapses while absorbing the bending input, and transmits the load to the possible cross member. Do not.
Further, since the cross member is set to be stronger than the coupling member, the cross member has a strength capable of withstanding each input, and the coupling member is suppressed while suppressing the buckling deformation of the cross member. Thus, the compression input in the axial direction (vehicle width direction) and the bending input due to the bending moment can be effectively absorbed.
Further, when the coupling member is crushed in the axial direction (vehicle width direction), it is possible to secure a deformation allowance that allows the lower part of the center pillar to move inward in the vehicle width direction. By securing the deformation allowance, the center pillar can be secured. The amount of intrusion into the upper passenger compartment can be suppressed.

In one embodiment of the present invention, the coupling member is constituted by a seat mounting bracket for supporting a passenger seat.
According to the above configuration, the seat mounting bracket that supports the seat is used to effectively suppress the compression input in the axial direction (vehicle width direction) and the bending input due to the bending moment while suppressing buckling deformation of the cross member. In addition, the amount of intrusion into the vehicle interior above the center pillar can be suppressed by securing the deformation allowance below the center pillar.

In one embodiment of the present invention, the outer side portion of the cross member in the vehicle width direction is formed with high strength relative to the inner side portion of the cross member in the vehicle width direction.
The outer side in the vehicle width direction of the cross member and the inner side in the vehicle width direction of the cross member may be formed integrally with a tailored blank, or may be formed with separate members.
According to the above configuration, only the outer side portion in the vehicle width direction of the cross member that requires strength can be configured with high strength, so that an increase in weight and an increase in cost can be suppressed.

In one embodiment of the present invention, the vehicle width direction outer side portion of the cross member and the vehicle width direction inner side portion of the cross member are configured as separate members, and the outer side portion is on the upper side with respect to the inner side portion. Are joined and fixed.
According to the above configuration, with respect to a bending moment from the side sill at the time of a side collision, an effective load is applied from the outer side in the vehicle width direction of the cross member positioned on the upper side to the inner side in the vehicle width direction of the cross member positioned on the lower side. Can be transmitted.

In one embodiment of the present invention, a reinforcing portion extending in the vehicle width direction is integrally formed on the upper portion of the cross member.
You may set the above-mentioned reinforcement part to a bead.
According to the above configuration, the strength of the cross member against the bending moment from the side sill can be improved.

In one embodiment of the present invention, a boundary portion between the outer side portion of the cross member in the vehicle width direction and the inner side portion of the cross member in the vehicle width direction is disposed between the tunnel portion and the side sill in the lower part of the floor panel in the vehicle front-rear direction. It is arranged on the upper side position corresponding to the frame member provided so as to extend in the direction, or on the tunnel part side from the upper side position.
The frame member described above may be set as a floor frame.
According to the said structure, the load from a side sill at the time of a side collision can be supported by the frame member of a floor panel lower part via the vehicle width direction outer side part of a high strength cross member.

In one embodiment of the present invention, a space is provided between the lower end of the side sill coupling region of the coupling member and the upper portion of the floor panel so as to compressively deform the side sill coupling region when a side collision load is input. Is.
According to the above configuration, by providing the above-described space portion, the side sill coupling region of the coupling member is surely compressed and deformed at the initial input of the side impact load, and the deformation margin of the center pillar lower part is further ensured. Can be secured.

  According to the present invention, the side sill side end portion of the cross member is disposed at a position spaced apart from the side sill, and the coupling member for connecting the side sill side end portion of the cross member and the side surface of the side sill is provided. Since this coupling member is set to have a lower strength than the cross member, and the strength of the cross member coupling region of the coupling member is higher than the strength of the side sill coupling region of the coupling member, The input side impact load is received in the side sill joint region where the strength of the joint member between the side sill and the cross member is low in the initial stage of input, and then the strength of the joint member is high against the bending moment from the side sill. The cross member is made to receive a load in the joint region, and the cross member has a strength capable of withstanding their input, While suppressing the buckling deformation of the loss member, it can effectively absorb the compression input in the axial direction (vehicle width direction) and the bending input due to the bending moment, and further secure the deformation allowance at the lower part of the center pillar. There is an effect that it is possible to suppress the amount of intrusion into the upper passenger compartment.

The schematic perspective view which shows the vehicle body structure provided with the vehicle body lower part structure of the vehicle of this invention The perspective view which shows the vehicle body lower part structure of a vehicle 2 is a cross-sectional view taken along line AA in FIG. Sectional view showing the interrelated structure between the cross member and nut plate Exploded perspective view of cross member and nut plate 3 is an enlarged view of the main part of FIG. The principal part expansion perspective view of FIG. 2 is a cross-sectional view taken along line BB in FIG. 7 is an enlarged front view of the main part of FIG. Exploded perspective view of coupling member, cross member vehicle width direction outer side, cross member vehicle width direction inner side Nut plate perspective view Sectional drawing which shows the other Example of the vehicle body lower part structure of a vehicle

  While suppressing the buckling deformation of the cross member, it effectively absorbs the compression input in the axial direction (vehicle width direction) and the bending input due to the bending moment, and further secures the deformation allowance at the lower part of the center pillar to secure the vehicle at the upper part of the center pillar. In the vehicle body lower part structure of the vehicle in which a cross member extending in the vehicle width direction is provided between the tunnel part at the top of the floor panel and the side sill to which the center pillar is coupled, for the purpose of suppressing the amount of intrusion into the room, A side sill side end portion of the cross member is disposed at a position spaced apart from the side sill, and a coupling member for coupling the side sill side end portion of the cross member and the side surface of the side sill is provided, the coupling member Is set to be lower in strength than the cross member, and the strength of the cross member coupling region of the coupling member is less than that of the side sill coupling region of the coupling member. It was realized in structures that configured to be higher than the degree.

An embodiment of the present invention will be described in detail with reference to the drawings.
The drawing shows a lower body structure of a vehicle. In FIG. 1, a floor panel 1 forming a bottom surface of a passenger compartment is provided, and at the center of the floor panel 1 in the vehicle width direction, it projects into the passenger compartment and extends in the front-rear direction of the vehicle. The tunnel portion 2 (so-called floor tunnel) is formed integrally or integrally. This tunnel part 2 is the center of the vehicle body rigidity.

  A rear seat pan 3 is connected to the rear portion of the floor panel 1 described above, and a rear floor 4 that forms the bottom surface of the luggage compartment is integrally formed on the rear side of the rear seat pan 3 so that the rear portion of the rear floor 4 is formed. A spare tire pan 5 recessed downward is integrally formed in the middle in the vehicle width direction.

Further, side sills 6 as vehicle body rigid members extending in the front-rear direction of the vehicle are provided on both sides of the floor panel 1 in the vehicle width direction (however, only the right side is shown in the drawing).
As shown in FIGS. 2 and 3, the side sill 6 has a side sill inner section 7, a side sill reinforcement 8, and a side sill outer 9. It is a strength member.

A hinge pillar 11 extending upward from the front portion of the side sill 6 described above and a center pillar 12 extending upward from the middle portion in the front-rear direction of the side sill 6 are provided. Each of the pillars 11 and 12 is a vehicle body strength member that supports a front door and a rear door (not shown) so as to be opened and closed.
The hinge pillar 11 is a vehicle body rigid member having a hinge pillar outer section and a hinge pillar inner and having a hinge pillar closed section extending in the vertical direction. A hinge pillar reinforcement is provided between the hinge pillar outer and the hinge pillar inner as necessary.

The center pillar 12 includes a center pillar outer, a center pillar reinforcement, and a center pillar inner, and is a vehicle body rigid member having a center pillar closed section extending in the vertical direction. The roof side rail 13 and the side sill 6 are fixed upright.
Here, the space surrounded by the hinge pillar 11, the side sill 6, the center pillar 12, and the roof side rail 13 is set as the entrance / exit 14 (door opening) of the front seat occupant and the center pillar. 12, a space surrounded by the side sill 6, the quarter pillar 15, and the roof side rail 13 is set as a passenger entrance / exit 16 (door opening) of the rear seat occupant.

  A pair of left and right rear side frames 17 are provided on both sides of the rear seat pan 3 and the rear floor 4 in the vehicle width direction so as to be substantially continuous with the pair of left and right side sills 6 and 6 in the longitudinal direction of the vehicle.

Incidentally, a cross member 20 (so-called No. 2 cross member) extending in the vehicle width direction between the tunnel portion 2 at the top of the floor panel 1 and the side sill 6 corresponding to the entrance 14 of the front seat passenger. Is provided.
Further, a cross member 30 extending in the vehicle width direction is formed between the tunnel portion 2 at the top of the floor panel 1 and the side sill 6 so as to be spaced apart from the cross member 20 in the front-rear direction. (So-called No. 2.5 cross member) is provided.

Further, a rear cross member 40 (so-called No. 3 cross member) extending in the vehicle width direction is provided between the rear portion of the floor panel 1 and the front portion of the rear seat pan 3, and the rear portion of the rear seat pan 3 and the rear floor 4 are provided. A rear cross member 50 (so-called No. 4 cross member) extending in the vehicle width direction is provided between the front portion and the front portion.
The cross members 20 and 30 and the rear cross members 40 and 50 described above are vehicle body rigid members, and the cross members 20, 30, 40, and 50 are configured to improve the rigidity of the lower portion of the vehicle body. Yes.

On the other hand, as shown in FIGS. 2 and 3, a floor frame 18 is joined and fixed to the lower part of the floor panel 1, and extends between the lower surface of the floor panel 1 and the floor frame 18 in the front-rear direction of the vehicle. A closed section 19 is formed.
In this embodiment, the above-mentioned floor frame 18 has its front portion positioned in the middle of the side sill inner 7 and the vertical wall portion of the tunnel portion 2 in the vehicle width direction, and as the floor frame 18 goes rearward, the front side of the floor frame 18 moves outward in the vehicle width direction. It is arrange | positioned in planar view slant form so that it may be located in the direction.

  2 to 5, the cross member 20 includes an upper piece 20a, a front piece 20b, a joining flange piece 20c formed by bending forward from the lower end of the front piece 20b, and a rear piece 20d. (Refer to FIG. 4) and a joining flange piece 20e bent rearward from the lower end of the rear piece 20d form a main body portion 20A of the cross member 20, and an outer end portion of the main body portion 20A in the vehicle width direction. Are provided with joint flange pieces 20f, 20g, and 20h that are joined and fixed to the side sill inner 7. Further, a joint flange piece that is joined and fixed to the vertical wall of the tunnel portion 2 at the inner end in the vehicle width direction of the main body portion 20A. 20i, 20j, and 20k are provided.

  Here, the cross member 20 is formed by integrally forming the above-described pieces 20a to 20k, the main body portion 20A of the cross member 20 is formed in a cross-sectional hat shape, and the joining flange pieces 20c and 20e below the floor member 1 A closed cross section 21 (see FIG. 4) extending in the vehicle width direction is formed between the floor panel 1 and the cross member 20.

  Further, a bead 22 as a reinforcing portion for preventing buckling of the cross member 20 is formed on the inner side in the vehicle width direction of the main body portion 20A of the cross member 20. As shown in FIGS. 2 and 4, the bead 22 is a reinforcing portion that is recessed downward from the upper piece 20 a of the cross member 20 and extends in the vehicle width direction. Of course, the beads may be provided.

Moreover, as shown in FIGS. 3, 4, and 6, in the vicinity of the coupling end portion of the cross member 20 with the side sill 6 on the outer side in the vehicle width direction, an impact absorbing portion that reduces the impact at the time of a side collision is provided. A notch 23 is provided.
As shown in FIGS. 5 and 6, the notch 23 is a fragile part that is notched inward in the vehicle width direction in the vicinity of the coupling end of the cross member 20 with the side sill inner 7. The front ridge line X between the upper piece 20a and the front piece 20b and the ridge line Y on the rear side between the upper piece 20a and the rear piece 20d are arranged in the vicinity of the connecting end with the side sill inner 7. It is constructed by cutting out inward.
Thus, it is possible to provide an appropriate shock absorbing portion by notching the ridge lines X and Y having high strength and providing the notches 23 at the front and rear.

Further, as shown in FIGS. 3 and 4, a nut plate 24 as a reinforcing member is disposed in the vicinity of the outer side in the vehicle width direction of the main body 20A of the cross member 20 as shown in FIGS. Further, an outer end 24a in the vehicle width direction of the nut plate 24 is provided so as to overlap with the above-described notch 23 in the vehicle width direction.
Here, the vehicle width direction outer side end portion 24a of the nut plate 24 as the reinforcing member is provided to be separated from the side sill inner 7 in the vehicle width direction inner side as shown in an enlarged view in FIG.

  Further, as shown in a perspective view of FIG. 5, the nut plate 24 described above is spot-welded to the lower surface of the upper piece 20a of the cross member 20, and concave portions with respect to the joints 24c and 24d. The substantially horizontal upper piece 24e, the front piece 24f, and the rear piece 24g that are provided are integrally formed. The front piece 24f of the nut plate 24 is a front piece of the cross member 20 in the closed section 21. The nut plate 24 has a rear piece 24g joined and fixed to the rear piece 20d of the cross member 20 in the closed section 21.

  Further, the upper piece 24e of the nut plate 24 described above is provided with a nut support member 26 in which openings 24h and 24i are formed as shown in FIGS. An inverted L-shaped locking piece 26 a is integrally formed with the nut support member 26.

The nut 25 is disposed in the opening 24h of the nut plate 24, and the engaging piece 26a is engaged in the opening 24i of the nut plate 24 to absorb manufacturing errors when the seat is attached. The nut support member 26 is configured such that it can be finely adjusted in the front-rear and left-right directions with the nut 25 provided.
The nut plate 24 is a seat mounting member for fixing an unillustrated passenger seat (front seat) to the cross member 20, and the nut plate 24 is provided between the cross member 20 and the floor panel 1. It is a plate that is provided in the closed section 21 (see FIG. 4) and uses the dead space to hold the occupant seat fixing nut 25.

Here, a bolt insertion hole 27 is formed in the upper piece 20a of the cross member 20 facing the nut 25 in the nut plate 24 in the vertical direction.
Moreover, the strength of the nut plate 24 as the reinforcing member and the seat mounting member is set to be weaker than the strength of the main body portion 20A of the cross member 20 described above.

  In this embodiment, the cross member 20 is formed of high-tensile steel (high-tensile steel plate), while the nut plate 24 is formed of a general steel plate so that the strength of the nut plate 24 is greater than the strength of the cross member 20. Although it is configured to be weak, instead of a configuration in which the strength is weakened due to the difference in the material, the plate thickness of the cross member 20 is set to be thicker than the plate thickness of the nut plate 24, and both 20, 24 are made of the same material. A configuration in which the strength of the nut plate 24 is relatively weakened may be adopted.

  Further, as shown in FIG. 4, the inner end 24b in the vehicle width direction of the nut plate 24 is provided so as to overlap the bead 22 of the cross member 20 by a distance L1 in the vehicle width direction. Due to the structure, the main body portion 20A of the cross member 20 is configured to be prevented from buckling.

  7 shows a cross member 30 (so-called No. 2.5 cross member) extending in the vehicle width direction between the tunnel portion 2 at the top of the floor panel 1 and the side sill 6 to which the center pillar 12 is coupled, and its peripheral structure. 2 is an enlarged perspective view of a main part of FIG. 2, in which the cross member 30 includes a first cross member 31 as an outer portion in the vehicle width direction of the cross member and a second cross as an inner portion in the vehicle width direction of the cross member. Member 32.

In this embodiment, the first cross member 31 is formed with high strength relative to the second cross member 32.
Here, as a specific configuration in which the first cross member 31 is formed with high strength with respect to the second cross member 32, the plate thickness of the first cross member 31 is thicker than the plate thickness of the second cross member 32. The first cross member 31 may be formed of high-tensile steel (high-tensile steel plate), while the second cross member 32 may be formed of a general steel plate.

  Further, in this embodiment, as shown in FIG. 7, the first cross member 31 and the second cross member 32 are configured by separate members, and the first cross member 31 is connected to the second cross member 32. 7, 8, and 9, the boundary Z between the first cross member 31 and the second cross member 32 corresponds to the floor frame 18 as the frame member described above. It is arranged on the upper side position to be or the tunnel part 2 side from the upper side position.

  Further, as shown in an enlarged view of the main part of FIG. 8 in FIG. 9, the first and second cross members 31, 32 described above have a predetermined length L <b> 2 at the outer side in the vehicle width direction from the boundary Z. The overlap portion is disposed at an upper position corresponding to the floor frame 18 described above.

  Further, as shown in FIG. 10 in an exploded perspective view of the first cross member 31 and the second cross member 32, the first cross member 31 includes an upper piece portion 31a, a front piece portion 31b, a rear piece portion 31c, A vehicle body rigid member integrally formed with front and rear pieces 31b and 31c and bending flanges 31d and 31e bent in the front and rear direction, and extends in the vehicle width direction in the middle of the upper piece 31a. A bead 33 as a downward convex reinforcing portion is integrally formed over the entire length in the longitudinal direction.

  Similarly, the second cross member 32 includes an upper piece portion 32a, a front piece portion 32b, a rear piece portion 32c, and joint flange portions 32d formed by bending the front and rear pieces 32b and 32c in the front-rear direction. A bead 34 as a downwardly convex reinforcing portion extending in the vehicle width direction is integrally formed over the entire length in the longitudinal direction in the middle of the upper piece portion 32a. .

Then, the above-described joining flange portions 31d, 31e, 32d, and 32e are spot-welded to the upper surface of the floor panel 1, so that the floor panel 1 and the first cross member 31 and the floor panel 1 and the second cross are connected. A closed cross section that is continuous in the vehicle width direction is formed between the members 32.
In addition, as shown in FIG. 7, the side sill 6 side end portion of the cross member 30 including the first and second cross members 31 and 32 is located at a predetermined distance from the side sill inner 7 of the side sill 6. It is arranged.

Similarly, the end of the cross member 30 on the tunnel portion 2 side is also disposed at a position spaced apart from the vertical wall portion of the tunnel portion 2.
And the coupling member 35 which couple | bonds the side sill side edge part of the 1st cross member 31 and the side surface of the side sill inner 7 in the side sill 6 is provided, the tunnel part side edge part of the 2nd cross member 32, and the tunnel part 2 A coupling member 36 that couples the vertical wall portion is provided.
Each of these coupling members 35 and 36 is constituted by a seat mounting bracket that supports a front seat (not shown) as a passenger seat.

As shown in the exploded perspective view of the above-described coupling member 35 in FIG. 10, the coupling member 35 includes an upper piece portion 35a, and a front piece portion 35b formed by bending downward from the front end of the upper piece portion 35a. A rear piece 35c bent downward from the rear end of the upper piece 35a, an inner piece 35d bent downward from the inner end in the vehicle width direction of the upper piece 35a, and the inner piece 35d A flange portion 35e that is bent in the horizontal direction from the lower end of the inner flange portion 35f, joint flange portions 35f and 35g that are bent from the front end and the rear end of the inner piece portion 35d outward in the vehicle width direction, and Bonding flange portions 35h, 35i, and 35j formed by bending from the outer ends in the vehicle width direction of the upper piece portion 35a, the front piece portion 35b, and the rear piece portion 35c are integrally formed.
The joint flange portion 35f is jointly fixed to the inner surface of the front piece portion 35b by spot welding in advance, and the joint flange portion 35g is jointly fixed to the inner surface of the rear piece portion 35c by spot welding in advance.

As shown in FIG. 7, the joining flange portion 35e of the coupling member 35 is joined and fixed to the upper piece portion 31a of the first cross member 31, and the front piece portion 35b and the rear piece portion 35c of the joining member 35 are joined to the first cross member 31a. Each of the joining flange portions 35h, 35i, and 35j of the coupling member 35 is joined and fixed to the front piece portion 31b and the rear piece portion 31c of the member 31. The inner 7 is joined and fixed to the surface on the passenger compartment side.
Further, the above-described coupling member 35 is set to have a lower strength than the cross member 30, and the strength of the cross member coupling region C of the coupling member 35 is higher than the strength of the side sill coupling region S of the coupling member 35. It is configured as follows.

In other words, the cross member coupling region C is configured as a box having four sides surrounded by an upper piece portion 35a, a front piece portion 35b, a rear piece portion 35c, and an inner piece portion 35d. It is configured in an open shape in which three sides are surrounded by the portion 35a, the front piece portion 35b, and the rear piece portion 35c, and the strength of the cross member coupling region C is configured to be higher than the strength of the side sill coupling region S. Is.
Furthermore, as shown in a front view in FIG. 9, the side sill coupling region S is compressed and deformed between the lower end of the side sill coupling region S of the coupling member 35 and the upper portion of the floor panel 1 when a side collision load is input. Therefore, a space 37 is provided.

In addition, as shown in FIGS. 8 and 9, a nut plate 38 is attached to the inside of the coupling member 35 constituted by a seat mounting bracket.
As shown in a perspective view of FIG. 11, the nut plate 38 includes a substantially horizontal upper piece 38a and front and rear mounting pieces 38b, 38c formed by bending downward from both front and rear ends of the upper piece 38a. And two openings 38d and 38e formed in the upper piece 38a.

Further, a nut support member 39 to which a nut N is fixed by welding in advance is provided at a lower portion, and a locking piece 39a is integrally formed on the nut support member 39 so as to be bent downward.
Then, the nut N on the lower surface of the nut support member 39 is loosely fitted into the opening 38d of the nut plate 38, and the locking piece 39a is inserted into the other opening 38e so as to absorb manufacturing errors at the time of mounting the seat. The nut support member 39 is configured so that it can be finely adjusted in the front-rear and left-right directions with the nut N provided.

  Here, the front and rear attachment pieces 38b, 38c of the nut plate 38 are fixed to the front piece portion 35b and the rear piece portion 35c of the coupling member 35 by welding. On the other hand, a bolt insertion hole 35k through which a bolt (not shown) for attaching a sheet is inserted is formed in the upper piece portion 35a of the coupling member 35.

  As shown in FIG. 7, the coupling member 36 that couples the second cross member 32 and the tunnel portion 2 is formed in a substantially bilaterally symmetric structure with the coupling member 35.

By the way, as shown in FIG. 8, the center pillar 12 described above includes a center pillar inner 41, a center pillar reinforcement 42, and a center pillar outer 43 that are joined and fixed to each other, and a center pillar that extends in the vertical direction of the vehicle is closed. A vehicle body rigid member having a cross section 44, wherein the lower part of the center pillar inner 41 passes through the side sill closed cross section 10 between the side sill inner 7 and the side sill reinforcement 8 of the side sill 6, , 8 are extended downward between the lower joints.
Further, the lower portion of the center pillar outer 43 is formed integrally or integrally with the side sill outer 9.

Further, a retractor support bracket 45 for supporting a retractor (not shown) is attached between the upper joint portions of the side sill inner 7 and the side sill reinforcement 8 described above.
In the figure, arrow F indicates the front of the vehicle, arrow OUT indicates the outside of the vehicle, and arrow UP indicates the upper side of the vehicle.

The operation of the vehicle body lower structure thus configured will be described.
As shown in FIG. 8, the side sill side end of the first cross member 31 and the side sill inner 7 are not directly connected, and the side sill side end of the first cross member 31 is predetermined from the side sill inner 7. The first cross member 31 and the side sill inner 7 are connected to each other by a connecting member 35, and the strength of the connecting member 35 is that of the cross member 30 and the first cross member. Since the strength of the cross member coupling region C of the coupling member 35 is set to be higher than the strength of the side sill coupling region S, the following effects are exhibited.

  That is, the side collision load input through the center pillar 12 and the side sill 6 at the time of a side collision of the vehicle is caused by the side sill coupling region S of the relatively low strength coupling member 35 being crushed at the initial input stage. Since the impact energy is absorbed, it is possible to secure a deformation allowance in which the lower part of the center pillar 12 can move a predetermined amount inward in the vehicle width direction corresponding to the amount of crushing.

  After that, the side pillar 6 is displaced so that the upper side of the center pillar 12 is tilted into the vehicle interior, so that a bending moment acts on the side sill 6. Since the load is received in the member coupling region C and the cross member coupling region C is crushed while absorbing the bending input, the load can be prevented from being transmitted to the possible cross member 30.

  Further, the above-described cross member 30, particularly the first cross member 31, is set to have a high strength with respect to the coupling member 35, and the first cross member 31 has a strength capable of withstanding a bending input caused by a bending moment. Therefore, it is possible to effectively absorb the compression input in the axial direction (vehicle width direction) and the bending input due to the bending moment by the above-described coupling member 35 while suppressing the buckling deformation of the cross member 30. Can do.

  As described above, the vehicle body lower part structure of the embodiment shown in FIGS. 1 to 11 is arranged in the vehicle width direction between the tunnel part 2 at the upper part of the floor panel 1 and the side sill 6 to which the center pillar 12 is coupled. The vehicle body lower part structure of the vehicle is provided with an extending cross member 30, and the side sill 6 side end portion of the cross member 30 is disposed at a position spaced from the side sill 6 by a predetermined distance. A coupling member 35 that couples the side sill 6 side end and the side surface of the side sill 6 is provided. The coupling member 35 is set to be lower in strength than the cross member 30, and the cross member coupling region C of the coupling member 35 It is comprised so that intensity | strength may become higher than the intensity | strength of the side sill joint area | region S of this coupling member 35 (refer FIG. 1, FIG. 8).

  According to this configuration, the side sill joint region S having a low strength in the joint member 35 between the side sill 6 and the cross member 30 in the initial stage of the input of the side impact load inputted through the center pillar 12 and the side sill 6. The side sill joint region S is crushed in the axial direction (vehicle width direction) while absorbing the load, and absorbs impact energy.

Thereafter, the bending moment from the side sill 6 receives a load in the cross member coupling region C where the strength of the coupling member 35 is high, and the cross member coupling region C is crushed while absorbing the bending input, and the load is applied as much as possible. Do not tell the cross member 30.
Further, since the cross member 30 is set to have a higher strength than the coupling member 35, the cross member 30 has a strength capable of withstanding the above inputs, while suppressing the buckling deformation of the cross member 30. The coupling member 35 can effectively absorb the compression input in the axial direction (vehicle width direction) and the bending input due to the bending moment.

Further, when the coupling member 35 is crushed in the axial direction (vehicle width direction), it is possible to secure a deformation allowance that allows the lower portion of the center pillar 12 to move inward in the vehicle width direction by securing the deformation allowance. The amount of intrusion into the passenger compartment above the center pillar 12 can be suppressed.
Further, the coupling member 35 is composed of a seat mounting bracket that supports the passenger seat (see FIGS. 7 to 9).
According to this configuration, the seat mounting bracket for supporting the seat is used to suppress the buckling deformation of the cross member 30 and to effect the compression input in the axial direction (vehicle width direction) and the bending input due to the bending moment. In addition, the amount of intrusion into the vehicle compartment above the center pillar 12 can be suppressed by securing the deformation allowance below the center pillar 12.

In addition, the outer side in the vehicle width direction of the cross member 30 (see the first cross member 31) is formed with high strength relative to the inner side in the vehicle width direction of the cross member 30 (see the second cross member 32). (See FIGS. 7 to 9).
According to this configuration, only the outer side in the vehicle width direction of the cross member 30 that requires strength (see the first cross member 31 of the embodiment) can be configured to have high strength, and thus an increase in weight and cost increase can be suppressed. be able to.

In addition, an outer portion in the vehicle width direction of the cross member (see the first cross member 31) and an inner portion in the vehicle width direction of the cross member (see the second cross member 32) are configured as separate members, and the outer portion It is joined and fixed with the inner side (see the second cross member 32) facing upward (see the first cross member 31) (see FIGS. 7 and 10).
According to this configuration, the vehicle of the cross member positioned on the lower side from the outer side in the vehicle width direction of the cross member positioned on the upper side (see the first cross member 31) with respect to the bending moment from the side sill 6 at the time of a side collision. A load can be effectively transmitted to the inner portion in the width direction (see the second cross member 32).

Further, a reinforcing portion (see beads 33 and 34) extending in the vehicle width direction is integrally formed on the upper portion of the cross member 30 (see FIGS. 7 and 10).
According to the above configuration, the strength of the cross member 30 against the bending moment from the side sill 6 can be improved without increasing the number of parts.

In addition, a boundary portion Z between the vehicle width direction outer side portion of the cross member (see the first cross member 31) and the vehicle width direction inner side portion of the cross member (see the second cross member 32) An upper position corresponding to a frame member (see the floor frame 18) provided so as to extend in the vehicle front-rear direction below the floor panel 1 with the side sill 6, or disposed closer to the tunnel portion 2 than the upper position (See FIGS. 8 and 9).
According to this configuration, the frame member (floor frame) below the floor panel 1 receives a load from the side sill 6 at the time of a side collision via the outer side in the vehicle width direction of the high-strength cross member (see the first cross member 31). 18).

Further, a space 37 is provided between the lower end of the side sill coupling region S of the coupling member 35 and the upper portion of the floor panel 1 so as to compress and deform the side sill coupling region S when a side collision load is input. Yes (see FIG. 9).
According to this configuration, by providing the above-described space portion 37, the side sill coupling region S of the coupling member 35 is more reliably compressed and deformed at the initial stage of the input of the side impact load, and the lower portion of the center pillar 12 is deformed. The bill can be secured even more reliably.

FIG. 12 is a front view showing another embodiment of the lower body structure of the vehicle.
In the previous embodiment shown in FIGS. 1 to 11, the first cross member 31 and the second cross member 32 are formed by separate members, but in this embodiment shown in FIG. The cross member 31 and the second cross member 32 are substantially integrally formed.

That is, a material that becomes the first cross member 31 as an outer portion in the vehicle width direction of the cross member is provided by a member having a relatively thick plate thickness, and the member in the vehicle width direction of the cross member is formed by a relatively thin plate member. A material that becomes the second cross member 32 as an inner portion is provided, and a plate material in which these two materials are joined and fixed in advance is integrated into a hat shape in cross section by pressing, and each of the first and second cross members 31 is processed. , 32.
Thus, even if the cross member 30 is formed of a tailored blank, the first cross member 31 can be formed with high strength relative to the second cross member 32.

  Also in this embodiment shown in FIG. 12, other configurations, operations, and effects are the same as those in the previous embodiment. Therefore, in FIG. Detailed description is omitted.

In the correspondence between the configuration of the present invention and the above-described embodiment,
The vehicle width direction outer side portion of the cross member of the present invention corresponds to the first cross member 31 of the embodiment,
Similarly,
The inner part of the cross member in the vehicle width direction corresponds to the second cross member 32,
The reinforcing part corresponds to the beads 33 and 34,
The frame member corresponds to the floor frame 18,
The present invention is not limited to the configuration of the above-described embodiment.

DESCRIPTION OF SYMBOLS 1 ... Floor panel 2 ... Tunnel part 6 ... Side sill 12 ... Center pillar 18 ... Floor frame (frame member)
30 ... Cross member 31 ... 1st cross member (vehicle width direction outside part of cross member)
32 ... Second cross member (inner side in the vehicle width direction of the cross member)
33, 34 ... Bead (reinforcement part)
35 ... coupling member 37 ... space C ... cross member coupling region S ... side sill coupling region Z ... boundary

Claims (7)

A vehicle body lower part structure in which a cross member extending in a vehicle width direction is provided between a tunnel part at an upper part of a floor panel and a side sill to which a center pillar is coupled,
The side sill side end of the cross member is disposed at a position spaced apart from the side sill,
A coupling member for coupling the side sill side end of the cross member and the side surface of the side sill is provided,
The coupling member is set to be lower in strength than the cross member,
The vehicle body lower part structure of the vehicle configured such that the strength of the cross member coupling region of the coupling member is higher than the strength of the side sill coupling region of the coupling member. The vehicle body lower part structure according to claim 1, wherein the coupling member includes a seat mounting bracket that supports a passenger seat. The vehicle body lower part structure according to claim 1 or 2, wherein an outer portion in the vehicle width direction of the cross member is formed with high strength with respect to an inner portion in the vehicle width direction of the cross member. A vehicle width direction outer side portion of the cross member and a vehicle width direction inner side portion of the cross member are configured as separate members,
The vehicle body lower part structure according to claim 3, wherein the outer part is joined and fixed to the inner part. The vehicle body lower part structure according to any one of claims 1 to 4, wherein a reinforcing portion extending in a vehicle width direction is integrally formed on an upper portion of the cross member. A boundary between the outer side in the vehicle width direction of the cross member and the inner side in the vehicle width direction of the cross member,
The upper position corresponding to a frame member provided so as to extend in the vehicle front-rear direction below the floor panel between the tunnel portion and the side sill, or disposed closer to the tunnel portion than the upper position. The vehicle body lower part structure of any one of Claims 1. The space part is provided between the lower end of the side sill joint area | region of the said coupling member, and the said floor panel upper part in order to compress-deform this side sill joint area | region at the time of a side collision load input. The vehicle body lower part structure of description.

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