JP2020001484A - Lower body structure of vehicle - Google Patents

Abstract

To prevent an edge of an inner flange part disposed on a lower side frame from interfering with a fuel tank upon occurrence of side collision.SOLUTION: A lower body structure of a vehicle comprises: a floor 5, left and right lower side frame lowers 62 joined to an under-surface of the floor 5 and constituting a closed section 60s extending in a vehicle longitudinal direction at a space between themselves and the undersurface of the floor 5, and a fuel tank 9 disposed on the underside of the floor 5 and between the left and right lower side frame lowers 62. In the lower body structure of a vehicle, an easy-to-deform part 55 to be deformed more downward from the inner flange part 62a during side collision is formed at a position adjacent, inside in a vehicle width direction, to an inner flange part 62a extending inward in the vehicle width direction at an inner end of the lower side frame lower 62 in the vehicle width direction in the floor 5 and overlapping with the fuel tank 9 in a vehicle side view.SELECTED DRAWING: Figure 1

Description

  The present invention is arranged between a floor, left and right side frame lowers forming closed cross sections extending in the vehicle front-rear direction on both left and right sides of the floor, and below the floor and between the left and right side frame lowers. The present invention relates to a lower vehicle body structure of a vehicle including a fuel tank.

  As a side frame lower provided in the lower vehicle body structure of the vehicle described above, for example, it is configured as an inverted hat shape that opens upward in a front view and is joined to the lower surfaces of the left and right sides of the floor as a part of a side frame. A configuration is known (for example, see Patent Document 1).

  The lower side frame of Patent Literature 1 has an inner flange portion extending inward in the vehicle width direction from the upper end of the side wall on the inner side in the vehicle width direction and joined to the lower surface of the floor.

  By the way, in order to increase the capacity of the fuel tank as much as possible, it is preferable to arrange the layout so that the upper part is close to the floor and the side is close to the side frame. It is necessary to make the (tip) not to interfere with the fuel tank.

  For this purpose, Patent Document 1 described above employs a configuration in which the edge of the inner flange portion is directed obliquely upward with respect to the inside in the vehicle width direction (for example, see FIG. 5A of Patent Document 1). .

  In this way, by directing the edge of the inner flange portion in a direction not facing the side wall of the fuel tank, it is expected that interference with the fuel tank during a side collision can be avoided. It is desired to more reliably avoid interference with the tank.

JP 20070306076 A

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a lower vehicle body structure of a vehicle in which an edge of an inner flange portion provided in a side frame lower does not interfere with a fuel tank in a side collision.

  The present invention provides a floor, left and right side frame lowers joined to the lower surface of the floor and forming a closed cross section extending in the vehicle front-rear direction between the floor and the lower surface of the floor. An inner flange extending inward in a vehicle width direction at a vehicle width direction inner end of the side frame lower on the floor, the lower body structure of a vehicle including a fuel tank disposed between the side frame lowers. An easily deformable portion that is deformed downward from the inner flange portion at the time of a side collision is formed at a position adjacent to the portion on the inner side in the vehicle width direction and overlapping the fuel tank when viewed from the side of the vehicle.

  According to the above configuration, at the time of a side collision, the easily deformable portion is deformed downward from the inner flange portion, so that the easily deformable portion functions as a protector for the fuel tank with respect to the edge of the inner flange provided on the side frame lower. be able to.

  As an aspect of the present invention, the easily deformable portion is formed by a concave bead that is recessed downward with respect to its periphery and extends in the vehicle front-rear direction.

  According to the above configuration, since the easily deformable portion can be formed along the vehicle front-rear direction with respect to the fuel tank by the simple configuration of the concave bead, the fuel with respect to the edge of the inner flange extends over the entire vehicle front-rear direction of the fuel tank. The protector function of the tank can be enhanced.

As an aspect of the present invention, the floor includes a side frame upper surface portion constituting the upper surface of the closed cross section, and a side wall which is disposed adjacent to the side frame upper surface portion inward in the vehicle width direction and in which the easily deformable portion is formed. With a frame adjacent floor part,
The upper surface of the side frame is set to have higher rigidity than the floor portion adjacent to the side frame.

  According to the above configuration, by making the rigidity of the upper portion of the side frame higher than that of the floor portion adjacent to the side frame, the easily deformable portion formed on the floor portion adjacent to the side frame can be reliably deformed.

  As an aspect of the present invention, the above-mentioned closed section is provided with a node member that suppresses cross-sectional deformation of the closed section.

  According to the above configuration, it is possible to suppress a change in the direction of the edge of the inner flange portion due to the cross-sectional deformation of the side frame (closed cross section) at the time of a side collision.

  According to the present invention, it is possible to prevent the edge of the inner flange portion provided on the side frame lower from interfering with the fuel tank at the time of a side collision.

FIG. 2 is a plan view showing a lower vehicle body structure of the vehicle according to the embodiment. FIG. 2 is a bottom view showing a main part of the lower vehicle body structure of the embodiment. FIG. 2 is a perspective view showing a main part of a lower vehicle body structure on the right side of the vehicle according to the embodiment, as viewed from below and from the center in the vehicle width direction. FIG. 2 is a sectional view taken along the line AA in FIG. 1. Sectional drawing along CC line in FIG. Sectional drawing along the BB line in FIG. FIG. 4 is an explanatory view of an operation at the time of side collision of the lower vehicle body structure on the right side of the vehicle according to the embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the figure, the arrow F indicates the front of the vehicle, the arrow R indicates the right side of the vehicle, the arrow L indicates the left side of the vehicle, and the arrow U indicates the upper side of the vehicle. 1, the rear floor side panel and the side sill outer on the right side of the vehicle are omitted, and in FIG. 2, the rear suspension and the rear wheel house on the left side of the vehicle are omitted. In addition, "x" marks in FIG. 6 indicate spot welded portions, and the lower vehicle body structure of the vehicle according to the present embodiment has a symmetrical shape, and will be described based on the configuration on the right side of the vehicle unless otherwise indicated. And

  In the lower vehicle body structure of the vehicle according to the present embodiment, a floor panel 1 (see FIG. 2) that forms the floor surface of the vehicle compartment is provided, and the floor panel 1 projects into the vehicle interior at a substantially central portion in the vehicle width direction. A tunnel portion 2 (see FIGS. 1 and 2) extending in the front-rear direction is integrally formed.

  As shown in FIGS. 1 and 2, side sills 3 as vehicle body strength members are joined and fixed to both sides of the floor panel 1. For example, as shown in FIG. 4, the side sill 3 includes a side sill inner 3a and a side sill rain 3b, and has a closed cross section extending in the vehicle front and rear direction. A side sill outer 3c as a design panel forming a part of the body side is joined from the outside in the vehicle width direction.

  A pair of left and right floor frames 19 (see FIG. 2) extending in the vehicle front-rear direction is fixed to the lower surface of the floor panel 1 between the tunnel portion 2 and the side sill 3.

  As shown in FIGS. 2 and 3, a rear floor panel 5 constituting a rear floor of the vehicle body is integrally connected to a rear portion of the above-mentioned floor panel 1 via a kick-up portion 4 rising upward. On both sides of the rear floor panel 5, rear side frames 6 extending in the vehicle front-rear direction are provided.

  A front portion 5F of the rear floor panel 5 (hereinafter, referred to as "rear floor front portion 5F") forms a bottom surface of a rear seat, and as shown in FIGS. The rear floor rear portion 5R ") constitutes a luggage compartment floor, and a concave portion 5a which also serves as a spare tire pan or other parts which is recessed downward is integrally formed at a middle portion in the vehicle width direction.

  As shown in the figure, a rear cross member 8 for bridging between a pair of left and right rear side frames 6 in the vehicle width direction is disposed on each of the upper and lower sides of the rear floor panel 5.

  Specifically, as shown in FIGS. 2 and 3, a front rear cross member 8f extending in the vehicle width direction and connecting the rear side frames 6 on both sides in the vehicle width direction is provided at the front of the rear floor front portion 5F. It is joined and fixed from the lower surface side of 5F.

  A rear cross member upper 8mu (see FIG. 1) and a rear cross member lower 8md (see FIGS. 2 and 3) are provided at the upper and lower portions of the rear floor panel 5 at the boundary between the front portion 5F and the rear portion 5R. Are fixedly joined by spot welding or the like. Both of these 8mu and 8md are intermediate rear cross members 8m (so-called No. 4 cross members) extending in the vehicle width direction and connecting the rear side frames 6 on both sides in the vehicle width direction. Closed cross sections vertically overlapping each other are formed between the rear floor panel 5 and between the rear cross member lower 8 md and the rear floor panel 5.

  Further, as shown in FIG. 3, a rear rear cross member 8r extending in the vehicle width direction so as to cross the recess 5a of the rear floor rear portion 5R and connecting the rear side frames 6 on both sides in the vehicle width direction is provided on the rear floor rear portion 5R. (A so-called No. 4.5 cross member) is joined and fixed from the lower surface side of the rear floor rear portion 5R. A closed cross section extending in the vehicle width direction is formed between the rear rear cross member 8r and the rear floor panel 5.

  As shown in FIGS. 1 to 3, a rear wheel house 7 is provided outside the rear side frame 6 in the vehicle width direction. The rear wheel house 7 is configured by joining a rear wheel house outer 7b and a rear wheel house inner 7a.

  The rear portion of the side sill 3 extends until it reaches the front portion of the rear wheel house 7 disposed further rearward than the position corresponding to the rear end of the floor panel 1, and the rear ends of the side sill inner 3a and the side sill rain 3b are It is joined to the front of the rear wheel house inner 7a.

  That is, the rear portion of the side sill 3 and the rear wheel house 7 are disposed adjacent to the rear side frame 6 on the outer side in the vehicle width direction.

  As shown in FIGS. 4 to 6, the above-described rear side frame 6 has a vehicle body side having a closed section 60 s (closed section space) extending in the vehicle front-rear direction inside from the kickup section 4 to the rear end of the rear floor panel 5. And a rear floor side panel 61 (also referred to as a "rear side frame upper 61"), a rear side frame lower 62 disposed below the rear floor side panel 61, and the like throughout the vehicle longitudinal direction. ing.

  The rear floor side panel 61 is a panel that forms the upper surface of the rear side frame 6 and also forms both sides of the rear floor panel 5 (see FIGS. 1 and 4).

  That is, the rear floor panel 5 includes a rear floor side panel 61 and a rear side frame adjacent floor portion 5c disposed adjacent to the rear side frame 6 inside the vehicle width direction.

  The rear side frame adjacent floor portion 5c constitutes a central portion in the vehicle width direction of the rear floor panel 5, is adjacent to the rear floor side panel 61 on the inner side in the vehicle width direction, and is disposed substantially flush with the vehicle width direction. You.

  In the present embodiment, the rear floor side panel 61 is formed to be about three times thicker than the rear side frame adjacent floor portion 5c to have higher rigidity than the rear side frame adjacent floor portion 5c.

  As shown in FIGS. 4 to 6, the rear side frame lower 62 includes a vehicle width inner wall portion (6 a) that extends in the vehicle width direction inner side in the vehicle width direction and extends in the vertical direction while inclining outward in the vehicle width direction. A lower wall portion (6c) extending substantially horizontally outward in the vehicle width direction from a lower end portion of the vehicle width inner wall portion (6a) is integrally formed, and the vehicle width inner wall portion (6a) and the lower wall portion (6c) The rear side frame 6 forms a vehicle width inner wall portion 6a and a lower wall portion 6c, respectively.

  In this example, as shown in FIGS. 4 and 6, the rear side frame lower 62 has a part in the vehicle front-rear direction further divided into a rear side frame lower upper division member 62u and a rear side frame lower lower division member 62d. The rear side frame lower upper division member 62u and the vehicle width inner wall portion of the rear side frame lower lower division member 62d form a vehicle width inner wall portion 6a of the rear side frame 6.

  The above-mentioned rear floor side panel 61 and rear side frame lower 62 are formed with joining flanges 61a, 62a at the respective inner ends in the vehicle width direction (see FIGS. 4 to 6), and are formed by these joining flanges 61a, 62a. Triple bonding is performed by spot welding or the like in a state where the outer end 5ca of the floor portion 5c adjacent to the rear side frame of the rear floor panel 5 located on the inner side in the vehicle width direction with respect to the rear floor side panel 61 is sandwiched. See figure).

  The joining flange portions 61a, 62a are raised at the lower wall portion 6c of the rear side frame 6 by the vehicle width inner wall portion 6a and are located at the upper end thereof. Therefore, they are also referred to as kick-up flanges, and are substantially inward in the vehicle width direction. It protrudes horizontally (see FIG. 4).

  On the other hand, as shown in the figure, the rear floor side panel 61 and the rear side frame lower 62 are also formed with joining flanges 61b, 62b at the outer ends in the vehicle width direction, and these joining flanges 61b, 62b are It is joined to an inner panel of a vehicle body component disposed outside in the width direction with respect to the rear side frame 6.

  In this example, the joining flange portions 61b and 62b are joined to the side sill inner 3a as the inner panel of the vehicle body component at a portion corresponding to the side sill 3 in the vehicle front-rear direction of the rear side frame 6 (see FIGS. Particularly, at portions corresponding to the rear wheel house 7 (see FIGS. 4 to 6), the vehicle body parts are joined to a rear wheel house inner 7 a as the inner panel (see FIGS. 1 to 3).

  Accordingly, the rear side frame 6 forms a closed cross section 60 s extending in the vehicle front-rear direction between the rear floor side panel 61 and the rear side frame lower 62 and the inner panel of the vehicle body component disposed outside in the width direction. (See, for example, FIGS. 4 to 6).

As shown in FIG. 2, the rear side frame 6 is joined to the rear end of the above-described floor frame 19 whose front end is fixedly joined to the lower surface of the floor panel 1. Further, the rear side frame 6 has a front portion corresponding to the rear floor front portion 5F in the vehicle front-rear direction, as shown in FIGS. The rear portion corresponding to the rear floor rear portion 5R is configured as a straight portion 6f that extends substantially horizontally in a straight line in the vehicle rear direction.
As shown in FIG. 3, the inclined portion 6s is inclined upward from the front end to the rear corresponding to the rising height of the kick-up portion 4.

  As shown in FIG. 2, the rear wheel house 7 is disposed in the vehicle front-rear direction from the rear portion of the inclined portion 6s of the rear side frame 6 to the straight portion 6f, and has a vehicle width relative to the front portion of the inclined portion 6s. The rear portion of the inclined portion 6s correspondingly extends in such a manner as to detour the rear wheel house 7 inward in the vehicle width direction, and the straight portion 6f extends in this manner. It extends linearly from the rear end of the inclined portion 6s to the rear of the vehicle.

  As shown in FIG. 3, the inclined portion 6 s is inclined upward toward the rear with the rear floor front portion 5 </ b> F disposed above the floor panel 1 via the kick-up portion 4. , Are formed so as to protrude downward toward the front with respect to the rear floor front portion 5F. As a result, the lower portion of the inclined portion 6s below the lower surface of the rear floor front portion 5F is erected with respect to the rear floor front portion 5F so that the vehicle width inner wall portion 6a of the inclined portion 6s becomes a vertical wall shape ( 3 and 4 to 6).

  Thus, below the rear floor front portion 5F, the inclined portions 6s of the pair of right and left rear side frames 6, which protrude below the lower surface of the rear floor front portion 5F, and the front rear cross member 8f (the kick-up portion 4). A space 9s surrounded by the middle rear cross member 8m when viewed from the bottom of the vehicle is configured (see FIG. 2), and at least the upper portion of the fuel tank 9 is stored in the space 9s (see FIG. 3). The fuel tank 9 is supported on the vehicle body side using a pair of left and right tank bands 9a and 9b (see FIG. 1). In this example, the front portions of the tank bands 9a, 9b are fastened and fixed to the front rear cross member 8f, and the rear portions of the tank bands 9a, 9b are fastened and fixed to the intermediate rear cross member 8m.

On the other hand, as shown in FIG. 3, the rear portion of the side sill 3 extends horizontally in the vehicle front-rear direction such that the lower surface maintains substantially the same height as the lower surface of the floor panel 1.
As a result, as shown in the figure, the rear portion of the side sill 3 disposed adjacent to the inclined portion 6s on the outer side in the vehicle width direction projects downward with respect to the lower surface of the inclined portion 6s inclined upward toward the rear. The vehicle width inner wall portion 30 (hereinafter, referred to as a “side sill kick-up portion 30”) of the downwardly projecting portion is erected downwardly in a vertical wall shape with respect to the lower surface of the inclined portion 6 s.

  In this example, the side sill kick-up portion 30 is formed so that the length of the downwardly protruding portion becomes longer toward the rear side in accordance with the shape of the inclined portion 6s which is inclined upward toward the rear side with respect to the rear floor front portion 5F. I have.

  As shown in FIGS. 2 and 3, the rear suspension 10 (only the right side of the vehicle is shown) of the present embodiment is a torsion beam type suspension, and a trailing arm 11 provided on the rear suspension 10 has a front end 12 The arm front end is provided below the inclined portion 6s of the rear side frame 6 via the shaft member 13 (see FIG. 5) so that the rear portion swings up and down around the arm front end portion 12 (hereinafter referred to as the "arm front end portion 12"). It is supported by the support 20.

  Here, reference numeral 14 in FIGS. 2 and 3 denotes a torsion bar having a U-shaped cross section that connects the left and right trailing arms 11 (only the right side of the vehicle is shown), and similarly, reference numeral 15 denotes a torsion bar 14, Reference numeral 16 denotes a plate-shaped spring lower end receiving member in which a flat spring lower end receiving surface (not shown) is formed upward at a corner portion between the trailing arm 11 and a portion behind the torsion bar 14. Shows a spring upper end receiving member joined to the lower surface of the rear side frame 6 above the spring lower end receiving member 15 with the flat spring upper end receiving surface 16a facing downward. It should be noted that illustration of a damper or the like that is interposed between the upper end of the rear wheel house 7 and the rear end of the trailing arm 11 and that can expand and contract in the vertical direction is omitted.

As shown in FIG. 5, a supported structure 120 that is supported by the arm front end support portion 20 via a bolt 131 and a nut 132 as the shaft member 13 is formed at the arm front end portion 12.
As shown in FIG. 5, the supported structure 120 includes an inner cylinder 121 inserted through the shaft member 13, a rubber member 122 surrounding the inner cylinder 121, and an outer cylinder 123 provided on the outer periphery of the rubber member 122. It is composed.

  As shown in FIG. 3, the arm front end support portion 20 surrounds the inner and outer sides and the front side in the vehicle width direction with respect to the arm front end portion 12, and is disposed in a U-shape as viewed from the lower side of the vehicle. A U-shaped portion 21 (also referred to as an “arm front end support main body portion 21”) is provided.

  The U-shaped portion 21 includes a vehicle width inner wall portion 23 and a side sill kick-up portion 30 which are disposed in a vertical wall shape on each side of the arm front end portion 12 in the vehicle width direction, and a front side with respect to the arm front end portion 12. The side sill kick-up portion 30 and the front wall portion 24 bridging the vehicle width inner wall portion 23 in the vehicle width direction.

  The vehicle width inner wall portion 23 is joined to the vehicle width inner wall portion 6a of the rear side frame 6 via a joining flange portion 23a (see FIG. 3), and as shown in FIG. 2, the front wall portion 24 is joined to the joining flange portion 24a. And is joined to the side sill kick-up portion 30 of the side sill inner 3a via the joining flange portion 24b.

  As shown in FIG. 5, the vehicle width inner wall portion 23 and the side sill kick-up portion 30 are formed with through holes 23h and 3h, respectively, through which the shaft member 13 is inserted, and are formed by the peripheral edges of the through holes 23h and 3h. The arm front end portion 12 is pivotally supported via a shaft member 13 bridged between the inner and outer wall portions 23, 30.

  The tip of the bolt 131 as the shaft member 13 is fastened by a nut 132. The fastening portion between the tip of the bolt 131 and the nut 132 corresponds to a protruding portion that protrudes from the vehicle width inner wall portion 23 toward the fuel tank 9. The nut cap 133 made of an elastic member such as rubber is used for the fuel tank 9. It is covered when viewed from the side (see FIG. 5).

  Further, as shown in FIG. 3, the vehicle width inner wall portion 23 and the front wall portion 24 are formed as a single member via a ridgeline 25a (bent portion) so as to be substantially L-shaped when viewed from the bottom of the vehicle. 25 are integrally formed.

  Further, as shown in FIGS. 3 and 5, the arm front end support portion 20 of the present embodiment includes a brace member 80, a reinforcing member 90, and a gusset member 40 in addition to the U-shaped portion 21.

  As shown in the figure, the brace member 80 is bridged below the arm front end 12 to the reinforcing member 90 disposed adjacent to the vehicle width inner wall portion 23 of the U-shaped portion 21 and the lower surface of the side sill inner 3a. The opening of the U-shaped portion 21 formed downward is prevented.

  As shown in FIGS. 2, 3, and 5, the reinforcing member 90 is a member that serves both to support the brace member 80 and to reinforce the U-shaped portion 21, particularly the vehicle width inner wall portion 23. On the other hand, it is disposed adjacent to the vehicle width direction outer side (arm front end portion 12 side) so as to substantially overlap in a vehicle side view.

  As shown in FIG. 5, the brace member 80 has an inner end in the vehicle width direction corresponding to the arm front end 12 in the reinforcing member 90 when viewed from the side of the vehicle, by a brace mounting portion 81 including a bolt 81 a and a nut 81 b. It is fastened and fixed below.

  Specifically, as shown in FIG. 3, the inner end in the vehicle width direction of the brace member 80 is located at a position corresponding to a corner portion between the lower edge and the rear edge of the inner wall portion 23 in the reinforcing member 90 in a vehicle side view. , Bolt 81a and nut 81b.

  As shown in FIG. 5, in the brace attachment portion 81 of the reinforcing member 90 corresponding to the attachment position of the inner end of the brace member 80 in the vehicle width direction, the tip of the bolt 81a is fastened to the nut 81b. The portion is disposed so as to protrude from the reinforcing member 90 to the fuel tank 9 provided on the inner side in the vehicle width direction.

  As shown in FIGS. 3 and 5, the corners of the vehicle width inner wall portion 23 are separated from the reinforcing members 90 of the fastening portions in order to secure an arrangement space for the fastening portions of the bolts 81 a and the nuts 81 b in the brace attachment portion 81. Is formed as a covering portion 42c that bulges inward in the vehicle width direction in accordance with the protruding length of the brace mounting portion 81 inward in the vehicle width direction, and covers a fastening portion of the brace mounting portion 81 from the fuel tank 9 side in a vehicle side view. ing.

  As shown in FIG. 3, the gusset member 40 extends forward with respect to the front wall portion 24 of the U-shaped portion 21 so as to bridge the front wall portion 24 and the lower surface of the rear side frame 6. And among the vibrations input from the arm front end portion 12 as the vibration input point to the vehicle body to the arm front end support portion 20, the vibrations in the vehicle vertical direction and the front-rear direction are particularly minimized to the vibration input point. It is a reinforcing member that reinforces the U-shaped portion 21 so as to effectively lower it at a close position.

  By the way, the fuel tank 9 stored in the space 9s (tank storage space) below the rear floor front portion 5F is arranged, for example, as close as possible to the inclined portion 6s of the rear side frame 6 in order to secure the tank capacity. (See FIGS. 3 to 5).

  For this reason, the joint flange portions 61a, 62a, which are provided at the inner end in the vehicle width direction of the inclined portion 6s and are also referred to as kick-up flanges, are provided above the space 9s and at the corners on both sides. 9 and is provided substantially above or slightly above the upper wall of the fuel tank 9 and substantially coincides with the outer wall portion of the vehicle width of the fuel tank 9 in the vehicle width direction, or is provided slightly outside in the vehicle width direction. 5).

  Further, in the present embodiment, as shown in FIGS. 1 to 6, a concave bead 55 which is recessed downward with respect to a peripheral portion thereof and extends in the vehicle front-rear direction is provided outside the floor portion 5 c adjacent to the rear side frame in the vehicle width direction. Is formed.

  As shown in FIGS. 1 to 3, the concave bead 55 is formed as an easily deformable portion which is deformed downward from the joint flange portions 61 a and 62 a at the time of a side collision, and is a joint flange extending in the vehicle front-rear direction. Along the portions 61a and 62a, the rear side frame adjacent floor portion 5c is formed at a position adjacent to the joining flange portions 61a and 62a on the inner side in the vehicle width direction.

  In the present embodiment, the concave bead 55 is formed at a position overlapping with the fuel tank 9 when viewed from the side of the vehicle, that is, at a position substantially corresponding to the whole of the fuel tank 9 except the front and rear parts of the fuel tank 9 in the vehicle longitudinal direction (see FIG. ), And is formed at a position substantially immediately above the vehicle width outer wall (side wall) of the fuel tank 9 (see FIGS. 4 and 5).

  In other words, the concave bead 55 is formed closer to the edge of the joint flanges 61a and 62a (the front end on the inner side in the vehicle width direction) in the vehicle width direction and the vertical direction.

  Further, the concave bead 55 has a lower surface protruding downward in a cross-sectional view orthogonal to the vehicle front-rear direction, and is formed into a curved surface shape that is smoother than the edge portions of the joining flange portions 61a and 62a (see FIGS. 4 to 6).

  As shown in FIGS. 1 and 4 to 6, a reinforcing member of the rear side frame 6 is provided around the rear side frame 6 of the present embodiment in the vehicle front-rear direction, that is, at least inside the inclined portion 6 s (closed section 60 s). The rear side frame rain 50 and the joint members 71, 72, 73 (bulk head) (see FIGS. 1, 5, and 6) are provided.

  The rear side frame rain 50 is disposed at the inner corner in the vehicle width direction and at the lower corner in the closed section 60 s of the rear side frame 6, and extends from the front to the rear of the inclined portion 6 s as shown in FIGS. 1 and 6. It extends along the longitudinal direction of the vehicle.

  As shown in FIGS. 4 to 6, the rear side frame rain 50 includes a rain lower wall inner portion 51 extending in the vehicle width direction so as to be able to be joined to the lower wall 6 c of the rear side frame 6 from the upper surface thereof, and a vehicle width of the rear side frame 6. It is integrally formed with a rain inner wall lower side portion 52 extending upward from a vehicle width direction inner end of the rain lower wall inner portion 51 so as to be connectable to the inner wall portion 6a from the vehicle width direction outer surface.

  As shown in FIGS. 1 and 6, a plurality of joint members 71, 72, and 73 (bulk heads) are arranged at intervals in the vehicle front-rear direction on the inclined portion 6 s of the rear side frame 6. , A front node member 71 disposed at the front of the inclined portion 6s, an intermediate node member 72 disposed behind the front node member 71, and a rear node member disposed behind the intermediate node member 72 73.

  As shown in FIG. 6, the front-side joint member 71 includes a panel-shaped joint main body wall portion 71a that forms an orthogonal plane in the vehicle front-rear direction so as to partition a closed cross section 60s extending in the vehicle front-rear direction of the inclined portion 6s. A vehicle width outer edge joining flange portion 71b bent and formed so as to extend forward from the vehicle width direction outer end of the main body wall portion 71a, and extends forward from the vehicle width direction inner end of the joint main body wall portion 71a. The vehicle width inner edge joint flange portion 71c formed to be bent and the lower edge joint flange portion 71d formed to extend forward from the lower end of the joint body wall portion 71a are integrally formed.

  As shown in the figure, the intermediate joint member 72 includes a panel-shaped joint main body wall portion 72a that forms an orthogonal surface in the vehicle front-rear direction similarly to the front side joint member 71, and an outside of the joint main body wall portion 72a in the vehicle width direction. A vehicle width outer edge joining flange portion 72b bent so as to extend forward from the end, and a vehicle width inner edge joining flange portion bent so as to extend forward from the vehicle width direction inner end of the joint body wall portion 72a. 72c, a lower edge joint flange portion 72d bent to extend forward from the lower end of the node main body wall portion 72a, and an upper edge bent to extend rearward from the upper end of the node main body wall portion 72a. It is integrally formed with the joining flange portion 72e.

  As shown in the figure, the rear side joint member 73 bridges between the side sill inner 3a and the lower wall 6c of the rear side frame 6, and downwards from the front and rear edges of the joint main body wall 73a. An extended front wall 73b and a rear wall 73c (see FIG. 1) are provided. The upper and lower edges of the joint body wall 73a are respectively joined to the side sill inner 3a and the lower wall 6c of the rear side frame 6. Joining flange portions 73d and 73e are formed. Further, joining flange portions 73f and 73g are formed at the outer ends in the vehicle width direction of the front wall portion 73b and the rear wall portion 73c, and extend to the front and rear sides to join to the side sill inner 3a.

  As shown in FIG. 6, the front side joint member 71 has a vehicle width outer edge joining flange portion 71b joined to the side sill inner 3a from the vehicle width direction inside, and a vehicle width inner edge joining flange portion 71c has a vehicle width of the rear side frame 6. It is joined to the inner wall portion 6a from the outside in the vehicle width direction, and the lower edge joining flange portion 71d is joined to the lower wall portion 6c of the rear side frame 6 from above.

  As shown in the figure, the intermediate joint member 72 has a vehicle width outer edge joining flange portion 72b joined to the side sill inner 3a from the vehicle width direction inside, and a lower edge joining flange portion 72d has a lower wall portion of the rear side frame 6. 6c from above, a vehicle width inner edge joint flange portion 72c is joined to the vehicle width inner wall portion 6a of the rear side frame 6 from the outside in the vehicle width direction, and an upper edge joint flange portion 72e is joined to the rear floor side panel 61 from below. Joined.

  Next, the operation of the lower vehicle body structure of the vehicle when a collision object collides from the right side (at the time of a side collision) will be described with reference to FIGS. FIGS. 7A and 7B are operation explanatory diagrams corresponding to FIGS. 4A and 4B in an initial stage of side collision (when the concave bead 55 is in contact with the fuel tank 9) and in a later stage of lateral collision (after contact).

In the event of a side collision, the lower body structure of the vehicle is provided above the side sill 3 in a direction perpendicular to the vehicle front-rear direction, with the side sill 3 extending in the vehicle front-rear direction as the collision object enters from the right side of the vehicle. Further, the side doors and center pillars (not shown) are deformed so as to fall inward in the vehicle width direction (toward the passenger compartment).
The imaginary line in FIG. 7A shows the lower vehicle body structure of the vehicle shown in FIG. 4 before deformation due to a side collision.

  As a result, as shown in FIG. 7A, the rear side frame 6 disposed adjacent to the inside of the side sill 3 in the vehicle width direction moves to the side close to the fuel tank 9 inside the vehicle in the vehicle width direction. By deforming the inner side in the width direction so as to be inclined downward with respect to the outer side, the joining flange portions 61 a and 62 a (kick-up flange portion) provided at the inner end in the vehicle width direction of the rear side frame 6 are moved above the fuel tank 9. , The edge portion (the inner end in the vehicle width direction) is inclined downward and inward in the vehicle width direction, that is, toward the fuel tank 9 from the substantially horizontal posture.

  If the joint flanges 61a and 62a approach the fuel tank 9 as it is as the lower part of the vehicle deforms at the time of a side collision, the edges of the joint flanges 61a and 62a collide with the fuel tank 9. However, in the present embodiment, as shown in FIGS. 1 to 6, in the rear floor front portion 5F, a position adjacent to the joining flange portions 61a, 62a on the inner side in the vehicle width direction includes: As an easily deformable portion, a concave bead 55 that is recessed downward with respect to the periphery and extends in the vehicle front-rear direction is formed.

  For this reason, as shown in FIG. 7A, at the time of a side collision, the concave bead 55 is deformed downward before the joining flange portions 61 a and 62 a and pressed against the fuel tank 9. The concave bead 55 does not protrude at an acute angle like the edges of the joining flanges 61a and 62a, and has a smooth curved surface in contact with the fuel tank 9 (lower surface).

For this reason, the concave bead 55 contacts the fuel tank 9 more quickly than the joining flanges 61a and 62a, so that the fuel tank 9 is moved away from the joining flanges 61a and 62a as shown in FIG. 7B. It can be pushed down inward in the vehicle width direction.
The virtual line in FIG. 7B indicates a main part of the lower vehicle body structure of the vehicle shown in FIG. 7A.

  Further, when the concave bead 55 is pressed against the fuel tank 9 at the time of the collision, even if the concave bead 55 does not sufficiently remove the fuel tank 9 from the joint flange portions 61a and 62a, the concave bead 55 may be used. 55 is interposed between the joint flanges 61a, 62a and the fuel tank 9 by being deformed downward more quickly than the joint flanges 61a, 62a, and the joint flanges 61a, 62a abut on the fuel tank 9. Can be avoided.

  In this embodiment, as shown in FIGS. 1 to 6, by providing the joint members 71, 72, 73 on the closed cross section 60 s of the rear side frame 6, it is possible to prevent the rear side frame 6 from collapsing in a side collision. it can.

  More specifically, if the cross section of the rear side frame 6 collapses in the event of a side collision, the joint flanges 61a and 62a behave unpredictably, and the joint flanges 61a and 62a are positioned earlier than the concave bead 55. It is feared that the fuel tank 9 comes into contact with the fuel tank 9.

  On the other hand, as described above, the provision of the joint members 71, 72, 73 on the closed section 60s of the rear side frame 6 prevents the rear side frame 6 from collapsing in the side collision, and consequently the vehicle of the rear side frame 6 It is possible to prevent the joining flange portions 61a and 62a at the inner end in the width direction from exhibiting unpredictable deformation behavior. Thereby, the concave bead 55 can be pressed against the fuel tank 9 before the joining flange portions 61a, 62a and kept away from the joining flange portions 61a, 62a.

  Further, in the present embodiment, as shown in FIG. 5, the fastening portion between the tip of the bolt 131 provided on the shaft member 13 and the nut 132 and the brace attaching portion 81 are both connected from the vehicle width inner wall portion 23 to the fuel tank 9. , Which are covered from the fuel tank 9 side by the nut cap 133 and the covering portion 42c, respectively.

  Thus, it is possible to prevent the acute angle projecting portion toward the fuel tank 9 from directly colliding with the fuel tank 9 at the time of a side collision.

  As shown in FIGS. 1 to 6, the lower vehicle body structure of the vehicle according to the present embodiment described above includes a rear floor panel 5 (floor), which is joined to a lower surface of the rear floor panel 5 and is connected to a lower surface of the rear floor panel 5. The left and right rear side frame lowers 62 (side frame lowers) forming a closed cross section 60 s extending in the vehicle front-rear direction therebetween, and the fuel tank 9 disposed below the rear floor panel 5 and between the left and right rear side frame lowers 62. A lower body structure of a vehicle provided with a joining flange portion (61a, 62a) as an inner flange portion extending inward in the vehicle width direction at a vehicle width direction inner end of the rear side frame lower 62 in the rear floor panel 5. On the other hand, at a position adjacent to the inner side in the vehicle width direction and overlapping with the fuel tank 9 in a side view of the vehicle, the joining flange portion (61a, 6) Than a one in which concave bead 55 as deformable portion which is deformed downward is formed.

  According to the above configuration, at the time of a side collision, the concave bead 55 serving as the easily deformable portion is deformed downward from the joining flange portion (61a, 62a), so that the concave bead 55 is joined to the joining flange portion (61a,) 62a. Prior to this, the fuel tank 9 comes into contact with the fuel tank 9 provided below, and the fuel tank 9 is pushed and moved to the side (inward and downward in the vehicle width direction) away from the joining flange portions (61a, 62a). When the concave bead 55 deformed or deformed downward is interposed between the joining flange portion (61a, 62a) and the fuel tank 9, the edge (the inner end in the vehicle width direction) of the joining flange portion (61a, 62a) becomes fuel. The fuel tank 9 can be protected by avoiding direct contact with the tank 9.

As an embodiment of the present invention, the concave bead 55 is recessed downward with respect to its periphery and extends to the rear floor panel 5 in the vehicle front-rear direction (see FIG. 3).
According to the above configuration, the easily deformable portion can be formed along the vehicle front-rear direction with respect to the fuel tank 9 by the simple configuration of the concave bead 55, so that the joining flange portion is formed over the entire fuel tank 9 in the vehicle front-rear direction. The protector function of the fuel tank 9 with respect to the edge of (61a,) 62a can be enhanced.

  As an embodiment of the present invention, the rear floor panel 5 includes a rear floor side panel 61 serving as an upper surface portion of a side frame constituting an upper surface of a closed cross section 60 s, and a concave bead that is disposed adjacent to the rear floor side panel 61 on the inner side in the vehicle width direction. The rear floor side panel 61 has a rigidity higher than that of the side frame adjacent floor portion 5c.

  According to the above configuration, by making the rigidity of the rear floor side panel 61 higher than that of the side frame adjacent floor portion 5c, the concave bead 55 formed on the side frame adjacent floor portion 5c at the time of a side collision is joined to the joining flange portion (61a,). Deformation toward the fuel tank 9 can be surely performed more quickly than 62a.

  As an embodiment of the present invention, a closed section 60s is provided with joint members 71, 72, 73 for suppressing cross-sectional deformation of the closed section 60s (see FIGS. 1 and 6).

  According to the above configuration, by providing the joint members 71, 72, and 73 on the closed section 60s, it is possible to prevent the rear side frame 6 from collapsing in cross section at the time of side collision.

  Thus, the edge of the joining flange portion (61a, 62a) directed upward and inward in the vehicle width direction of the fuel tank 9 is deformed downward (fuel tank 9) before the concave bead 55. Can be suppressed.

  The present invention is not limited to the configuration of the above-described embodiment, but can be formed in various embodiments.

5. Rear floor panel (floor)
5c: floor portion adjacent to the side frame 9: fuel tank 55: concave bead (easy deformation portion)
60s: Closed section 61: Rear floor side panel (upper part of side frame)
62 ... Rear side frame lower (side frame lower)
62a ... joining flange part (inner flange part)
71, 72, 73 ... joint members

Claims (4)

A floor, left and right side frame lowers joined to the lower surface of the floor and forming a closed cross section extending in the vehicle front-rear direction between the floor and the lower surface of the floor, and the left and right side frame lowers below the floor and A lower vehicle body structure of a vehicle including a fuel tank disposed therebetween,
On the floor, at a position adjacent to the inner flange portion extending inward in the vehicle width direction at the inner end in the vehicle width direction of the side frame lower at the vehicle width direction inside and overlapping the fuel tank in a vehicle side view. A lower vehicle body structure of a vehicle in which an easily deformable portion that is deformed downward from the inner flange portion at the time of a side collision is formed. The vehicle lower body structure according to claim 1, wherein the easily deformable portion is formed by a concave bead that is recessed downward with respect to its periphery and extends in the vehicle front-rear direction. The floor includes a side frame upper surface portion that forms the upper surface of the closed cross section, and a side frame adjacent floor portion that is disposed adjacent to the side frame upper surface portion inward in the vehicle width direction and has the easily deformable portion formed thereon. Prepare,
3. The lower vehicle body structure of a vehicle according to claim 1, wherein the rigidity of the upper surface of the side frame is set higher than that of the floor portion adjacent to the side frame. The lower vehicle body structure of a vehicle according to any one of claims 1 to 3, wherein the closed cross section is provided with a node member that suppresses cross-sectional deformation of the closed cross section.

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