LOWER STRUCTURE OF VEHICLE BODY

Abstract

An upper corner part of upper cross member 25c (respectively lower corner part of upper cross member 25k) is formed by an inclined upper side part of upper cross member 25b (respectively inclined lower side part of upper cross member 25g) and an upper surface part of upper cross member 25a (respectively lower surface part of upper cross member 25f), an angle of an inclined lower side part of lower cross member 22e is smaller than the angle of the inclined lower side part of upper cross member 25g, a position P1 where a reference line L1 connecting the upper corner part of upper cross member 25c and the lower corner part 25k crosses a lower end of a subfloor cross member 20 is closer to an outside side than a connecting part 22d between the lower surface part of lower cross member 22c and the inclined lower side part of lower cross member 22e.Fig. 3.

Description

Title of the invention: LOWER STRUCTURE OF VEHICLE BODY Technical field

[0001] The present invention relates to a lower vehicle body structure. Prior art

[0002] A mechanism member such as a propulsion shaft and a plurality of superimposed devices are provided on a lower side of a floor panel constituting a floor part in a vehicle passenger compartment. There is a vehicle having a structure in which a space on the lower side of the floor part is widened by projecting an intermediate portion in a vehicle width direction of the floor panel upward in order to provide such mechanism members, devices and the like, for example.

[0003] The floor panel is arranged between side members on both sides in the width direction of the vehicle. The floor panel is reinforced by cross members extending between the side members present on both sides. Such a cross member which is joined respectively to an upper surface and a lower surface of the floor member is known, as described in Patent Document 1. Technical problem

[0004] When the floor panel is to be reinforced by providing the cross member as in the example of the structure in which the intermediate portion in the vehicle width direction of the floor panel is raised, a certain reinforcing effect can be achieved. However, in the case of a side collision and the like on a portion where a side portion of the floor panel is inclined upward, the side portion in the vehicle width direction of the cross member is deformed upward.

[0005] At this time, it is likely that the floor portion is greatly deformed so as to protrude from the vehicle passenger compartment side depending on the degree of deformation. Thus, in the structure of the example, a margin of improvement for suppressing the protruding deformation of the floor portion from the vehicle passenger compartment side, as well as for improving the safety of the occupants, has appeared.

[0006] The present invention has been made in order to solve this problem, and an object thereof is to provide a lower vehicle body structure which makes it possible to suppress deformation when the floor portion protrudes from the passenger compartment side of the vehicle. Technical solution

[0007] A vehicle body lower structure according to the present invention, in order to achieve the above-mentioned object, has a floor side member provided on both side portions in a vehicle width direction on the side of a lower surface of a floor panel and extending in a vehicle longitudinal direction, a side sill provided on an outer side in the vehicle width direction of each of the floor side members and extending in a vehicle longitudinal direction, and a floor crossmember provided on an upper surface of the floor panel and extending in the vehicle width direction so as to connect the side sills on both sides,the floor panel having a panel flat surface portion located on an intermediate portion in the vehicle width direction located on an upper vehicle side relative to each of the side portions in the vehicle width direction and has a relief shape as viewed from the front of the vehicle. In the lower vehicle body structure an underfloor crossmember extending in the vehicle width direction is provided on a lower surface of the floor panel in a position superimposed on the overfloor crossmember as viewed from above,an upper portion of the floor crossmember has an upper crossmember upper surface portion located on the intermediate portion in the vehicle width direction and an upper crossmember upper side inclined portion inclined toward a lower side as it proceeds toward an outer side from an outer side end in the vehicle width direction of the upper crossmember upper surface portion; an upper crossmember upper side corner portion is formed by the upper crossmember upper side inclined portion and the upper crossmember upper surface portion, , a floor crossmember lower portion has an upper crossmember lower surface portion joined to the panel flat surface portion and an upper crossmember lower side inclined portion inclined toward the lower side as it proceeds toward the outer side from the vehicle width direction outer side end of the upper crossmember lower surface portion and located on the vehicle width direction outer side of the panel flat surface portion, an upper crossmember lower side corner portion is formed by the upper crossmember lower side inclined portion and the upper crossmember lower surface portion,a lower portion of the underfloor crossmember has a lower crossmember lower surface portion located on the intermediate portion in the vehicle width direction and a lower side inclined lower crossmember portion inclined toward the lower side as it proceeds toward the outboard side from the outboard end in , the vehicle width direction of the lower cross member bottom surface portion, an inclination angle of the lower cross member bottom side inclined portion is set smaller than the inclination angle of the upper cross member bottom side inclined portion, and a position where a reference line connecting the upper cross member top side angle portion and the upper cross member bottom side angle portion intersects the bottom surface of the lower cross member bottom side inclined portion is arranged closer to the outer side in the vehicle width direction than a connecting portion between the lower cross member bottom surface portion and the lower cross member bottom side inclined portion.

[0008] For example, an outer side corner portion bent toward the outer side in the vehicle width direction is formed on a lower end of the upper crossmember lower side inclined portion, and the outer side corner portion is disposed on an inner side in the vehicle width direction relative to an inner side corner portion formed on an upper portion of the inner side in the vehicle width direction of the floor side member.

[0009] For example, a reinforcing member is provided inside a closed section of the floor side member; and the reinforcing member is provided at a position where the vehicle width direction outer side portion of the underfloor crossmember is joined to the floor side member.

[0010] For example, an outer side end portion in the vehicle width direction of the underfloor crossmember is joined to the side sill by crossing the floor side member. Benefits provided

[0011] According to the present invention, the deformation of the floor portion protruding from the passenger compartment side of the vehicle can be suppressed. Brief description of the drawings Fig.l

[0012] [fig.l] [fig.l] is a perspective view of a lower vehicle body structure according to the present invention as seen from below the vehicle; Fig. 2

[0013] [fig-2] [fig.2] is a perspective view in section along arrow AA of [fig.l] Fig. 3

[0014] [fig.3] [fig.3] is a view of a rear surface of a left outer side element of an underfloor cross member of [fig.l] and similar, seen from the rear of the vehicle. Description of the embodiments

[0015] An embodiment of a vehicle body lower structure according to the The present invention is described below with reference to the drawings ([fig.l] to 3).

[0016] In the drawings, the direction of an arrow Av indicates a front in a longitudinal direction of the vehicle. The terms "a front portion (front end) and a rear portion (rear end)" in the description of the embodiment correspond to a front portion and a rear portion in the longitudinal direction of the vehicle. Arrows D and G indicate a right side and a left side in a width direction of the vehicle, respectively, and the terms "left and right" in this embodiment correspond to the "left side" and the "right side" when an occupant is facing the front of the vehicle.

[0017] The vehicle body lower structure of this embodiment is a structure for suppressing deformation of a floor portion of a vehicle body on one side of the vehicle passenger compartment by effectively supporting a load acting on a side portion in a vehicle width direction of a floor panel 10 such as a side collision. The vehicle body lower structure comprises the floor panel 10, the floor side members 2 and 3, the side sills 6 and 7, a floor crossmember 25, and an underfloor crossmember 20. In this embodiment, the floor crossmember 25 and the underfloor crossmember 20 are arranged superimposed in a vertical direction of the vehicle by sandwiching the floor panel 10 therebetween.

[0018] The floor panel 10, the floor cross member 25 and the underfloor cross member 20 are formed substantially symmetrically to a longitudinal direction line of the vehicle passing through a center in the width direction of the vehicle. Thus, essentially, a portion of the left side will be described in the explanation of this embodiment, and a detailed explanation of the portion of the right side is omitted.

[0019] The floor panel 10 is a panel member disposed on the lower portion of the vehicle body, constituting a floor portion of a vehicle passenger compartment, and is a plate-shaped member extending from the vicinity of rear portions of the left and right front wheels (not shown) toward the rear of the vehicle as illustrated in [fig.l]. A dimension in the vehicle width direction of the floor panel 10 substantially corresponds to the dimension of the vehicle body in the vehicle width direction.

[0020] The floor panel 10 of this embodiment has a panel flat surface portion located on an intermediate portion in the vehicle width direction located on an upper vehicle side relative to each of the side portions in the vehicle width direction and has a relief shape as viewed from the front of the vehicle. The floor panel 10 has a left-side panel 12 and a right-side panel 13 constituting the panel flat surface portion. The left-side panel 12 and the right-side panel 13 are arranged at an interval from each other. in the vehicle width direction. That is, an opening (not shown) extending in the vehicle longitudinal direction is formed at a central portion in the vehicle width direction of the floor panel 10.

[0021] A floor tunnel 15 is provided at the opening. The floor tunnel 15 extends in the vehicle longitudinal direction so as to close the opening. That is, in this embodiment, the floor tunnel 15 is constituted by a separate member from the floor panel 10.

[0022] The floor tunnel 15 has, as illustrated in [fig.2], a high surface portion 15a, a left wall portion 15b, a right wall portion 15c, a left lower surface portion 15d, and a right lower surface portion 15e. The high surface portion 15a is disposed closer to an upper side of the vehicle than the left and right panels 12 and 13, has a high surface facing the upper side of the vehicle, and extends in the longitudinal direction of the vehicle.

[0023] The left wall portion 15b projects toward a lower side of the vehicle from a left side portion in the vehicle width direction of the upper surface portion 15a and extends in the longitudinal direction of the vehicle. The right wall portion 15c projects toward the lower side of the vehicle from a right side portion in the vehicle width direction of the upper surface portion 15a and extends in the longitudinal direction of the vehicle. The left side lower surface portion 15d projects toward the left side in the vehicle width direction from a lower end of the left wall portion 15b and extends in the longitudinal direction of the vehicle.The right side lower surface portion 15e projects toward the right side in the vehicle width direction from a lower end of the right wall portion 15c and extends in the vehicle longitudinal direction.

[0024] The floor tunnel 15 forms a hat-shaped section open toward a lower side of the vehicle by means of the upper surface portion 15a, the left wall portion 15b, the right wall portion 15c, the left-side lower surface portion 15d, and the right-side lower surface portion 15e in a view in the longitudinal direction of the vehicle.

[0025] Hereinafter, the left-side panel 12 of the floor panel 10 is described. The left-side panel 12 has a left-side upper surface portion 12a, a floor inclined portion 12b, an outer-side flat surface portion 12c, an outer-side flange portion 12d, and an inner-side flange portion 12e as shown in [fig.2]. The left-side upper surface portion 12a is a panel flat surface portion disposed on the left side in the vehicle width direction of the floor tunnel 15 and is a portion that is an essential part of the left side of the floor panel 10. The left-side upper surface portion 12a extends into the longitudinal direction of the vehicle and extends toward an outer side in the vehicle width direction from the floor tunnel 15. The floor inclined portion 12b extends with an inclination toward a lower side of the vehicle as it proceeds toward the outer side in the vehicle width direction from an outer side end in the vehicle width direction of the left side upper surface portion 12a and extends in the longitudinal direction of the vehicle. In this embodiment, the floor inclined portion 12b is inclined at an angle of about 45° toward a horizontal line extending toward an inner side in the vehicle width direction from the outer side flat surface portion 12c ([fig.3]).

[0026] The outer-side planar surface portion 12c extends toward the outer side in the vehicle width direction from the outer-side end in the vehicle width direction of the floor inclined portion 12b and extends in the vehicle longitudinal direction. A lower-side surface of the outer-side planar surface portion 12c is joined to an upper portion of the floor side member 2 on the left side. The outer-side flange portion 12d projects toward the upper vehicle side from the outer-side end in the vehicle width direction of the outer-side planar surface portion 12c and extends in the vehicle longitudinal direction. The outer-side flange portion 12d is joined to an inner-side surface in the vehicle width direction of the side sill 6.The inner-side flange portion 12e extends with an inclination toward the upper side of the vehicle as it proceeds toward the inner side in the vehicle width direction from an inner-side end in the vehicle width direction of the left-side upper surface portion 12a and extends in the longitudinal direction of the vehicle.

[0027] The right-side panel 13 is constituted symmetrically with the left-side panel 12 as described above and has a right-side upper surface portion 13a which is a panel flat surface portion, an inclined floor portion (not shown), an outer-side flat surface portion (not shown), an outer-side flange portion (not shown), and an inner-side flange portion 13e. The inclined floor portion extends with an inclination at an angle of about 45° toward the lower side of the vehicle as it proceeds toward the right side in the vehicle width direction from a right-side end in the vehicle width direction of the right-side upper surface portion 13a and extends in the longitudinal direction of the vehicle.In addition, the high surface portion 15a located in the center in the vehicle width direction of the floor tunnel 15 is located closer to the upper portion than the upper ends of the inner side flange portions 12e and 13e.

[0028] Hereinafter, the floor side members 2 and 3 and the side sills 6 and 7 are described. The floor side members 2 and 3 have the floor side member 2 on the left side and the floor side member 3 on the right side, as illustrated in [fig.l] and 2. The left and right floor side members 2 and 3 are highly rigid members constituting a frame of the vehicle body, arranged at an interval from each other in the vehicle width direction so as to form a left and right pair, and extend in the vehicle longitudinal direction. The floor side members 2 and 3 have a closed section of a substantially square shape when viewed in the vehicle longitudinal direction. The left side floor side member 2 is joined to a lower surface of the outer-side flat surface portion 12c of the left-side panel 12 by spot welding or the like, for example.The right side floor side member 3 is also joined to the right side panel 13 in a similar manner.

[0029] The side sills 6 and 7 are members extending in the vehicle longitudinal direction and are provided on the outer side in the vehicle width direction with respect to each of the left and right floor side members 2 and 3 and extend in the vehicle longitudinal direction as illustrated in [fig.l] to 3. The left side side sill 6 is provided on the left outer side in the vehicle width direction of the left side floor member 2 and extends in the vehicle longitudinal direction, for example. The left side side sill 6 has a hat-shaped section raised toward the inner side in the vehicle width direction when viewed in the vehicle longitudinal direction, and the inner side surface in the vehicle width direction of the left side side sill 6 is joined to the left side surface of the left side floor member 2.The side sill 7 on the right side is made in a similar manner to the side sill 6 on the left side and is joined to the side floor element 3 on the right side.

[0030] The floor crossmember 25 is next described. The floor crossmember 25 is a member extending in the vehicle width direction as illustrated in [fig.2] and 3, is joined to an upper surface of the floor panel 10 and is disposed at a position corresponding to the underfloor crossmember 20. As described above, the floor panel 10 is sandwiched by the underfloor crossmember 20 and the floor crossmember 25. Accordingly, the rigidity of the floor panel 10 is ensured. In addition, the vehicle width direction outer side portions of the floor crossmember 25 are provided at positions corresponding to the floor side members 2 and 3.

[0031] The upper portion of the floor cross member 25 has an upper cross member upper surface portion 25a and an upper cross member upper side inclined portion 25b. The upper cross member upper surface portion 25a is located on the intermediate portion in the vehicle width direction, is disposed at an interval from the vehicle upper side of the high surface portion 15a of the floor tunnel 15 and extends in the vehicle width direction so as to extend beyond the high surface portion 15a.

[0032] The upper crossmember upper side inclined portion 25b is a portion provided on each of the left and right sides of the floor crossmember 25 and inclined toward the lower side as it moves toward the outer side from the outer side end in the vehicle width direction of the upper crossmember upper surface portion 25a. The upper crossmember upper side inclined portions 25b are for example provided at an interval from the outer side in the vehicle width direction of the floor inclined portion 12b of the left side panel 12, and in this embodiment, the inclination angle with respect to the horizontal direction is set slightly smaller than the inclination angle (about 45°) of the floor inclined portion 12b.

[0033] As illustrated in [fig.3], the upper crossbar upper side corner portion 25c is formed by the upper crossbar upper side inclined portion 25b and the upper crossbar upper surface portion 25a. A seat support 28 is provided on an upper portion of the upper crossbar upper side corner portion 25c.

[0034] A front wall portion 25d ([fig.2]) facing the front of the vehicle is provided on a front portion of the floor crossmember 25, and a rear wall portion 25e ([fig.3]) facing the rear of the vehicle is provided on the rear portion. An upper portion of the front wall portion 25d is formed along the upper crossmember upper surface portion 25a and upper crossmember upper side inclined portions 25b on both left and right sides. In addition, the upper portion of the rear wall portion 25e is formed along the upper crossmember upper surface portion 25a and upper crossmember upper side inclined portions 25b on both left and right sides in a manner similar to the front wall portion 25d.

[0035] In addition, a front-side flange projecting toward the front side of the vehicle is provided on a lower end of the front wall portion 25d, and a rear-side flange projecting toward the rear side of the vehicle is provided on a lower end of the rear wall portion 25e. A lower portion of the floor crossmember 25 constituted by the front-side flange and the rear-side flange has an upper crossmember lower surface portion 25f, an upper crossmember lower-side inclined upper portion 25g, an upper crossmember outer-side lower surface portion 25h, and a vertical flange 25n.

[0036] The left side portion in the vehicle width direction of the upper cross member lower surface portion 25f is joined to the left side upper surface portion 12a of the left side panel 12, and the right ... the vehicle width is joined to the right side upper surface portion 13a of the right side panel 13. The center portion in the vehicle width direction of the upper crossmember lower surface portion 25f is recessed toward the vehicle upper side and is joined to the upper surface portion 15a, the left wall portion 15b, and the right wall portion 15c of the floor tunnel 15.

[0037] The upper crossmember lower side inclined portion 25g is a portion provided on each of the left and right sides of the floor crossmember 25 and inclined toward the lower side as it moves toward the outer side from the outer side end in the vehicle width direction of the upper crossmember upper surface portion 25f, is inclined at substantially the same inclination angle as the inclination angle of the floor inclined portion 12b, and is joined to the floor inclined portion 12b. In addition, the upper crossmember lower side angle portion 25k is formed by the upper crossmember lower side inclined portion 25g and the upper crossmember upper surface portion 25f.

[0038] The upper crossmember outer-side lower surface portion 25h extends toward the outer side in the vehicle width direction from a lower end of the upper crossmember lower-side inclined portion 25g and is joined to the upper surface of the outer-side flat surface portion 12c of the left-side panel 12, for example. A vertical flange 25n projects toward the upper side in the vehicle from the outer-side end in the vehicle width direction of the upper crossmember outer-side lower surface portion 25h and is joined to the outer-side flange portion 12d of the left-side panel 12, for example. A vicinity of the upper end of the vertical flange 25n may be joined to the inner-side surface in the vehicle width direction of the side sill 6, for example.In addition, an outer side corner portion 25m bent toward the outer side in the vehicle width direction is formed on a lower end of the upper cross member lower side inclined portion 25g.

[0039] The underfloor crossmember 20 is then described. The underfloor crossmember 20 is an element extending in the direction of the width of the vehicle so as to connect the left and right floor side elements 2 and 3 as illustrated in [fig.l]. The underfloor crossmember 20 has a central element 21, a left outer side element 22 and a right outer side element 23.

[0040] The central member 21 extends in the vehicle width direction so as to extend on both sides of the opening in the floor tunnel 15 as illustrated in [fig.l]. A central portion in the vehicle width direction in the upper part of the central member 21 is joined to the lower surface (rear surface) of the upper surface portion 15a of the floor tunnel 15. In addition, a vertical wall portion extending toward the vehicle lower side from both sides of the portion central part is joined to the left wall portion 15b and the right wall portion 15c of the floor tunnel 15. That is, an upper part shape of the central part in the vehicle width direction of the central member 21 follows a profile shape in the vehicle width direction of the floor tunnel 15. In addition, the inner side flange portion 12e of the left side panel 12 and the inner side flange portion 13e of the right side panel 13 are also joined to the left wall portion 15b and the right wall portion 15c. In addition, the outer side end portions 15wl and 15w2 in the vehicle width direction of the floor tunnel 15 are joined to the lower surface of the left side upper surface portion 12a of the left side panel 12 and to the lower surface of the right side upper surface portion 13a of the right side panel 13. In addition, they are joined to the floor crossmember 25 at the same locations.

[0041] The left outer side member 22 of the underfloor crossmember 22 is described below. The left outer side member 22 is joined to the left side portion in the vehicle width direction of the center member 21 and extends in the vehicle width direction, as shown in [fig.l] to 3. The outer side portion in the vehicle width direction of the left outer side member 22 is joined to the floor side member 2 on the left side. The left outer side member 22 further extends to the outer side in the vehicle width direction, intersects the floor side member 2 on the left side, and is joined to the side sill 6 on the left side. The left outer side member 22 includes the front wall portion 22a, the rear wall portion 22b, the lower crossmember lower surface portion 22c, and the lower crossmember lower side inclined portion 22e.

[0042] The front wall portion 22a of the left outer side member 22 has a wall surface facing the front of the vehicle and extends in the vehicle width direction. The inner side portion in the vehicle width direction of the front wall portion 22a of the left outer side member 22 is joined so as to continue to the outer side portion in the vehicle width direction of the center member 21. The outer side portion in the vehicle width direction of the front wall portion 22a of the left outer side member 22 is joined to the floor side member 2 on the left side. The rear wall portion 22b of the left outer side member 22 is also formed in a similar manner to the front wall portion 22a.

[0043] In addition, the front-side flange projecting toward the front side of the vehicle is provided on an upper end of the front wall portion 22a, and the rear-side flange projecting toward the rear side of the vehicle is provided on an upper end of the rear wall portion 22b, although not shown. The upper portion of the left outer-side member 22 constituted by the front-side flange and the rear-side flange extends along the left-side upper surface portion 12a, the floor inclined portion 12b, and the outer-side flat surface portion 12c of the left-side panel 12 and is joined to the left-side upper surface portion 12a and the floor inclined portion 12b. The rear-side flange is also constituted similarly to the front-side flange.

[0044] The lower portion of the left outer side member 22 of the underfloor crossmember 20 is constituted by the lower crossmember lower surface portion 22c and the lower crossmember lower side inclined portion 22e. The lower crossmember lower surface portion 22c is located on the intermediate portion in the vehicle width direction, connects a lower end of the front wall portion 22a and the lower end of the rear wall portion 22b and extends in the vehicle width direction. The inner side portion in the vehicle width direction of the lower crossmember lower surface portion 22c is joined so as to continue to the lower portion of the outer side portion in the vehicle width direction of the center member 21.

[0045] The lower crossmember lower side inclined portion 22e is inclined toward the lower side as it proceeds toward the outer side from the outer side end in the vehicle width direction of the lower crossmember lower surface portion 22c and is joined to the floor side member 2 on the left side, for example. An inclination angle formed by the lower crossmember lower side inclined portion 22e and a horizontal line extending the lower surface of the floor side member 2 toward the inner side in the vehicle width direction is set to be less than the inclination angle (about 45°) of the upper crossmember lower side inclined portion 25g.

[0046] Hereinafter, the right outer side member 23 is joined to the right side portion in the vehicle width direction of the center member 21 and extends in the vehicle width direction. The right outer side member 23 is formed so as to be symmetrical with the left outer side member 22 and has a front wall portion (not shown), a rear wall portion 23b, a lower crossmember lower surface portion 23c, and a lower crossmember lower side inclined portion 23e ([fig.l]).

[0047] In this embodiment, as illustrated in [fig.3], an intersection PI where a reference line L1 (broken line in [fig.3]) connecting the upper crossmember upper side corner portion 25c and the upper crossmember lower side corner portion 25k intersects the lower end of the lower crossmember lower side inclined portion 22e is disposed closer to the outer side in the vehicle width direction than a connecting portion 22d between the lower crossmember lower surface portion 22c and the lower crossmember lower side inclined portion 22e. The intersection PI is located closer to the lower side of the vehicle than the connecting portion 22d.

[0048] When the vehicle width direction outer side portions of the floor crossmember 25 and the underfloor crossmember 20 bear a side collision from outside the vehicle body, the underfloor crossmember 20 is easily deformed at the connecting portion 22d between the lower crossmember bottom surface portion 22c and the lower crossmember bottom side inclined portion 22e. On the other hand, when a side collision is borne, the upper crossmember top side corner portion 25c and the upper crossmember bottom side corner portion 25k must be deformed along the reference line L1 connecting them.

[0049] In this embodiment, the connecting portion 22d which is easily deformed with respect to the reference line L1 and the intersection PI is disposed on the inner side in the vehicle width direction, as described above. Thus, when the side collision is supported, since a gap between the intersection PI and the connecting portion 22d extends with a substantially linear inclination, a force acts, resisting a load in the vehicle width direction such as the side collision.

[0050] At this time, the underfloor crossmember 20 is deformed so as to be crushed toward the upper side in the inclination direction of the reference line L1 from the connecting portion 22d. By means of the deformation, the underfloor crossmember 20 is deformed in a direction in which the underfloor crossmember 20 rises, i.e., so as to rotate upward around the outer side portion in the vehicle width direction (counterclockwise in [fig.3]).

[0051] In addition, the upper crossmember upper side inclined portion 25b of the floor crossmember 25 is also deformed in the same rotational direction. That is, the upper crossmember upper side inclined portion 25b is deformed counterclockwise in [fig.3] around the upper crossmember upper side corner portion 25c. In such a case, the magnitude of the deformation toward the upper side of the vehicle is less in the floor crossmember 25 than in the underfloor crossmember 20. Thus, according to this embodiment, such deformation in which the floor portion protrudes from the passenger compartment side of the vehicle can be suppressed when a load such as a side collision is supported.

[0052] Furthermore, as described above, the outer side corner portion 25m is provided on the lower part of the floor crossmember 25. On the other hand, the floor side members 2 and 3 have a closed section of a substantially square shape in the view in the longitudinal direction of the vehicle, and an inner side corner portion 5 is formed on the inner side portions in the vehicle width direction on the upper parts of the floor side members 2 and 3. The outer side corner portion 25m is disposed on the inner side in the vehicle width direction relative to the inner side corner portion 5.

[0053] As described above, the outer side corner portion 25m and the side corner portion interior 5 are high rigidity portions relative to their peripheries. Thus, when the aforementioned lateral collision is sustained, the underfloor crossmember 20 (left and right outer side members 22 and 23) located below a gap between the outer side corner portion 25m and the inner side corner portion 5 has less rigidity than the outer side corner portion 25m and the inner side corner portion 5, and thus, it is easily crushed. Accordingly, by causing rotational deformation of the underfloor crossmember 20 and the floor crossmember 25 to occur easily, a deformation suppression effect in which the floor portion protrudes toward the vehicle passenger compartment can be improved.

[0054] A reinforcing member 4 is provided inside the closed section of the left and right floor side members 2 and 3. The reinforcing member 4 is a plate-shaped member joined to a wall surface constituting the closed section and has a hole provided in the center. The reinforcing member 4 on the left side, for example, is provided adjacent to a position where the floor side member 2 on the left side and the left outer side member 22 are joined. The reinforcing member 4 on the right side is also arranged in a similar manner.

[0055] By providing the reinforcing member 4, the strength of the floor side members 2 and 3 is improved. Accordingly, a difference in strength between the floor side members 2 and 3 where the reinforcing member 4 is located and the portion closer to the inner side in the vehicle width direction than said position is greater. Accordingly, the underfloor crossmember 20 located below the gap between the outer side corner portion 25m and the inner side corner portion 5 is crushed more easily.

[0056] In addition, an extension portion 22f extending toward the outer side in the vehicle width direction is provided on a lower end of the lower crossmember lower side inclined portion 22e of this embodiment. The intermediate portion in the vehicle width direction of the left side extension portion 22f is joined to the lower portion of the floor side member 2 on the left side, for example, and the left outer side portion in the vehicle width direction of the left side extension portion 22f is joined to the lower portion of the side sill 6 on the left side. A right side extension portion 23f is also constituted in a manner similar to the left side extension portion 22f. By a configuration such as above, when a load such as a side collision is borne, the independent rotation of the side sill 6 with respect to the crossmembers 20 and 25 can be suppressed.

[0057] Furthermore, although an explanation by illustration is omitted, a cross member extending in the vehicle width direction is provided on the vehicle front side of the floor cross member 25. The cross member is disposed at an interval from the floor cross member floor. A seat support is provided on an upper portion of the crossmember. In addition, the floor panel (e.g., right-hand side panel) between this crossmember and the floor crossmember 25 may be planar or have an opening. When the opening is provided, an upwardly open box-shaped panel material may be attached to the opening, and a lithium-ion battery or the like may be disposed within the panel material.

[0058] The description of this embodiment is an example for describing the present invention and does not limit the invention as included in the scope of the claims. In addition, the configuration of each part of the present invention is not limited to the embodiment, and various modifications within a technical field such as within the scope of the claims are possible.

[0059] For example, in this embodiment, the underfloor crossmember 20 is made up of three elements (the central element 21, the left outer side element 22 and the right outer side element 23), but this is not limiting. It may be made up of a single element extending in the direction of the width of the vehicle. List of reference signs

[0060] 2 left side floor side element 3 right side floor side element 4 reinforcement element 5 corner part inside side 6 left side threshold 7 right side threshold 10 floor panel 12 left side panel 12a upper surface part left side (flat surface part of the panel) 12b inclined part of floor 12c part of flat surface on the outer side 12d part of flange outside side 12th part of the bridle on the inside 13 right side panel 13a upper surface part right side (flat surface part of the panel) 13th part of the bridle on the inside 15 floor tunnel 15a upper surface part 15b part of left wall 15c right wall section 15d lower surface part left side 15th part of lower surface right side 20 underfloor crosspieces 21 central element 22 element left outer side 22a front wall section (left only) 22b rear wall part 22c lower surface portion of lower cross member 22d connecting part 22nd inclined part lower side of lower cross member 22f extension part 23 element right outer side 23b rear wall part 23c lower surface part of lower cross member 23d connecting part 23rd inclined part of lower crosspiece 23f extension part 25 crosspiece on floor 25a upper surface part of upper cross member 25b inclined part upper side of upper crosspiece 25c corner part upper side of upper crosspiece 25d front wall part 25th part of the rear wall 25f lower surface part of upper cross member 25g inclined part lower side of upper cross member 25h lower surface part outer side of upper cross member 25k corner part lower side of upper cross member 25m corner part outside 25n vertical flange 28 seat support L1 reference line PI intersection List of cited documents Patent documents

[0061] [Patent Document 1] JP 2010-208395 A.

Claims

1. Claims Lower vehicle body structure having: a floor side member (2, 3) provided on both side portions in a vehicle width direction on the side of a lower surface of a floor panel (10) and extending in a vehicle longitudinal direction; a side sill (6, 7) provided on an outer side in the vehicle width direction of each of the floor side members (2, 3) and extending in a vehicle longitudinal direction; and a floor crossmember (25) provided on an upper surface of the floor panel (10) and extending in the vehicle width direction so as to connect the side sills (6, 7) on both sides, wherein the floor panel (10) has a panel flat surface portion (12, 13) located on an intermediate portion in the vehicle width direction located on a vehicle upper side relative to each of the side portions in the vehicle width direction and has a relief shape as viewed from the front of the vehicle, the lower vehicle body structure being characterized in that an underfloor crossmember (20) extending in the vehicle width direction is provided on a lower surface of the floor panel (10) at a position superimposed on the overfloor crossmember (25) as viewed from above; a floor crossmember upper portion (25) has an upper crossmember upper surface portion (25a) located on the intermediate portion in the vehicle width direction and an upper crossmember upper-side inclined portion (25b) inclined toward a lower side as it proceeds toward an outer side from a vehicle width direction outer-side end of the upper crossmember upper surface portion (25a), and an upper crossmember upper-side corner portion (25c) is formed by the upper crossmember upper-side inclined portion (25b) and the upper crossmember upper surface portion (25a); a lower portion of the floor cross member (25) has an upper cross member lower surface portion (25f) joined to the panel flat surface portion and an upper cross member lower side inclined portion (25g) inclined toward the lower side as it runs toward the outer side from the outer side end in the vehicle width direction of the upper cross member lower surface portion (25f) and located on the outer side in the vehicle width direction of the panel flat surface portion (12, 13), and an upper cross member lower side corner portion (25k) is formed by the upper cross member lower side inclined portion (25g) and the upper cross member lower surface portion (250;an underfloor crossmember lower portion (20) has a lower crossmember lower surface portion (22c) located on the intermediate portion in the vehicle width direction and a lower crossmember lower side inclined portion (23e) inclined toward the lower side as it proceeds toward the outer side from the outer side end in the vehicle width direction of the lower crossmember lower surface portion (22c), and an inclination angle of the lower crossmember lower side inclined portion (23e) is set smaller than the inclination angle of the upper crossmember lower side inclined portion (25g);and a position where a reference line connecting the upper crossmember upper side corner portion (25c) and the upper crossmember lower side corner portion (25k) intersects the lower surface of the lower crossmember lower side inclined portion (23e) is disposed closer to the outer side in the vehicle width direction than a connecting portion between the lower crossmember lower surface portion (22c) and the lower crossmember lower side inclined portion (23e).;

2. The vehicle body lower structure according to claim 1, wherein an outer-side corner portion (25m) bent toward the outer side in the vehicle width direction is formed on a lower end of the upper crossmember lower-side inclined portion (25g), and the outer-side corner portion (25m) is disposed on an inner side in the vehicle width direction relative to an inner-side corner portion (5) formed on an upper portion of the inner side in the vehicle width direction of the floor side member (2, 3).

3. A vehicle body lower structure according to claim 1 or 2, wherein a reinforcing member (4) is provided inside a closed section of the floor side member (2, 3); and the reinforcing member (4) is provided at a position where the outer side portion in the vehicle width direction of the underfloor crossmember (20) is joined to the floor side element (2, 3).

4. A vehicle body lower structure according to one of claims 1 to 3, wherein an outer end portion in the vehicle width direction of the underfloor crossmember (20) is joined to the side sill (6, 7) by crossing the floor side member (2, 3).

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