JP2009269444A - Vehicle lower structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a damage of a fuel tank caused by abuttment of a frame member against a flange part in a positive and less-expensive manner. <P>SOLUTION: A first protect plate 15 is arranged in a region corresponding to a side of a right bulging-out part 8d of a fuel tank 8 in such a way that a vehicle inner flange 7a of a rear frame 7 is held with a central horizontal part 3c, wherein the first protect plate 15 includes a first extension part 15a overlapping on the vehicle inner flange 7a and a first bending part 15b extending from the vehicle inner end of the first extension part 15a and curved upward. The first extension part 15a is arranged over the upper surface of the fuel tank 8 and at the same time set to have a length substnatially the same as the forward and rearward length of a right bulging-out part 8d. The first bending part 15b is curved from the vehicle inner end of the first extension part 15a toward a first protrusion 11 of a central horizontal part 3c and the extremity end of the first bending part 15b is stored in a space just below the first protrusion 11 under a state of covering the flange 7a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lower body structure of a vehicle, and more particularly to prevention of damage to a fuel tank disposed below a floor panel.

A fuel tank of a vehicle is surrounded by a highly rigid frame such as a side frame or a cross member, and is disposed below the floor panel, and is attached to the frame via a mounting bracket. Due to such a structure, when the vehicle collides, the fuel tank may be damaged due to interference between the fuel tank and the edge of the end of the frame due to the movement of the fuel tank or the vehicle side frame.
A layout where the fuel tank and the end of the frame do not overlap may be considered, but there is a floor panel above the fuel tank, and there is a problem with obstacles when driving under the fuel tank. The range of degrees of freedom is limited.

  Patent Document 1 proposes a technique in which a frame having a flange portion with an end projecting on the fuel tank side is joined to the lower surface of the floor panel, and an inclined portion extending upward toward the fuel tank is formed on the flange portion. Yes.

  According to this Patent Document 1, even when the fuel tank moves to the flange portion at the time of a collision from the side of the vehicle, the fuel tank is guided by the inclined portion and moves downward without coming into contact with the end portion of the flange portion. Thus, damage to the fuel tank due to the end of the flange portion can be prevented.

JP 2007-30607 A

However, in general, the frame around the fuel tank is a highly rigid side frame or a cross member and is a steel plate having a thickness of at least 2 mm. Extending the flange portion of such a steel plate many times as usual is not realistic in terms of vehicle weight or vehicle cost.
In addition, even if an inclined portion is simply formed, a collision from the horizontal direction does not always occur.Therefore, if a load is applied obliquely from above, there is a possibility of damage due to the edge of the end portion of the inclined portion. Still concerned.

  An object of the present invention is to reliably and inexpensively prevent damage to a fuel tank due to contact of a flange portion of a frame member.

  The lower vehicle body structure according to claim 1 includes a fuel tank disposed below the floor panel of the vehicle body, a frame member of the vehicle body disposed near the fuel tank and joined to the lower surface of the floor panel by a joining flange portion. In the structure in which the end of the joint flange portion is provided so as to protrude to the fuel tank side, a protect plate is provided between the joint flange portion and the fuel tank to cover the end portion of the joint flange portion. The protect plate has an extended portion that is joined to the flange portion and extends toward the fuel tank side, and a bent portion that is provided at the end of the extended portion on the fuel tank side and bent upward. It is characterized by that.

  The lower body structure according to claim 2 is the invention according to claim 1, wherein a protruding portion protruding upward is provided in the vicinity of the joint flange portion of the floor panel, and the bent portion end portion of the protect plate is accommodated inside the protruding portion. It is characterized by that.

  The lower vehicle body structure of claim 3 is characterized in that, in the invention of claim 1 or 2, the protect plate is provided only at a predetermined portion where the joining flange portion and the fuel tank are close to each other.

  The lower vehicle body structure of claim 4 is characterized in that, in the inventions of claims 1 to 3, the plate thickness of the protect plate is made thinner than the plate thickness of the frame member.

  The lower body structure of claim 5 is characterized in that, in the inventions of claims 1 to 4, the protect plate, the joining flange portion, and the floor panel are welded together at the same time.

  According to the first aspect of the present invention, the protect plate is provided between the joining flange portion and the fuel tank so as to cover the end portion of the joining flange portion, and the protect plate is joined to the flange portion. Since the fuel tank has an extending portion extending to the fuel tank side and a bent portion provided at the end of the extending portion on the fuel tank side and bent upward, the fuel tank is brought into contact with the flange portion of the frame member. Can be reliably and inexpensively prevented. That is, since the protect plate is a separate member from the frame member, the protect plate that is thinner and cheaper than the frame member can be used only in a necessary range according to the layout of the fuel tank. Furthermore, since it has a bent part that is bent upward, the edge of the end of the protect plate does not come into contact with the fuel tank regardless of the direction in which the collision load is input, and the fuel tank is surely brought into contact with the surface. Can prevent damage. In addition, since it is not necessary to form an additional portion in the frame member, the yield is improved and the cost of the lower body structure can be reduced.

  According to the second aspect of the present invention, the projecting portion projecting upward is provided in the vicinity of the joint flange portion of the floor panel, and the bent portion end portion of the protect plate is accommodated inside the projecting portion, so that the fuel tank is lowered downward. In addition, the bent portion can be installed without interfering with the floor panel, and the contact with the fuel tank is further ensured.

  According to the invention of claim 3, since the protect plate is provided only at a predetermined portion where the joining flange portion and the fuel tank are close to each other, it is possible to prevent damage to the fuel tank with the minimum necessary protect plate.

  According to the invention of claim 4, since the plate thickness of the protect plate is made thinner than that of the frame member, it is possible to prevent damage to the fuel tank while maintaining the strength of the frame member.

  According to the invention of claim 5, since the protect plate, the joining flange portion, and the floor panel are welded together at the same time, it is possible to achieve both of ensuring the joining strength and improving the productivity.

  Hereinafter, the best mode for carrying out the present invention will be described.

  The lower vehicle body structure of the present invention is a structure in which a fuel tank is disposed below a rear portion of a kick-up portion reinforced with a cross member of a floor panel, and a floor panel is formed on the upper surface side of the fuel tank. Applied.

  As shown in FIGS. 1 to 3, the lower body structure 1 of an automobile includes a rear floor panel 3 having a thickness of 0.8 mm extending rearward from the front floor panel 2 and a cargo floor panel 4 extending rearward from the rear floor panel 3. The both ends of the rear floor panel 3 in the vehicle width direction are coupled to a pair of left and right rear side sills 5, and the rear floor panel 3 has a front horizontal portion 3a, a kick-up portion 3b, a central horizontal portion in order from the front end to the rear. 3c, a central inclined portion 3d, and a rear horizontal portion 3e are formed.

  The kick-up portion 3b is formed in a step-up form from the rear end portion of the front horizontal portion 3a and continues to the central horizontal portion 3c. The kick-up portion 3b is reinforced by a cross member 6 extending in the vehicle width direction. The cross member 6 is coupled to the upper surface of the kick-up portion 3b of the rear floor panel 3 or the vicinity thereof to form a closed section in cooperation with the rear floor panel 3, and both ends in the vehicle width direction are coupled to the rear side sill 5. Has been.

Rear frames 7 and 7 of steel plates having a hat-shaped cross section and a thickness of 2.6 mm are formed on the lower surfaces of both ends in the vehicle width direction of the rear floor panel 3 in cooperation with the rear floor panel 3 to form a closed cross section. The rear frame 7 extends from the front horizontal part 3 a to the rear end of the cargo compartment floor panel 4 while forming a closed cross section after being curved upward along the kick-up part 3 b of the rear floor panel 3 from the front horizontal part 3 a. .
The rear frame 7 is located on the inner side of the vehicle with respect to the rear side sill 5 and forms a frame structure in which the frame member 5a forming the rear end portion of the rear side sill 5 and the rear frame 7 are continuous in the front-rear direction. . That is, the rear end of the vehicle inner side surface of the rear side sill 5 and the front end of the frame member 5a are joined in a superposed state, and the curved portion of the frame member 5a toward the vehicle outer side at the rear side inside the vehicle is the front end of the rear frame 7. Polymerization connected.

  A fuel tank 8 is disposed below the rear horizontal portion 3e and below the central horizontal portion 3c, the central inclined portion 3d, and the rear horizontal portion 3e of the rear portion of the kick-up portion 3b of the rear floor panel 3, and the rear floor panel 3b. A service hole 10 that opens the fuel pump unit of the fuel tank 8 to the upper side of the rear floor panel 3 is formed in the central portion of the front horizontal portion 3 c of the panel 3. The service hole 10 is normally covered with a lid member (not shown), and the lid member is fastened to the periphery of the service hole 10 of the rear floor panel 3 with a plurality of fasteners so as to be opened and closed.

  Further, a bead-shaped first protrusion 11 protruding upward in the front-rear direction on the rear right side of the central horizontal portion 3c in the vehicle traveling direction and a second protrusion 12 protruding upward on the rear left side are provided. It has been. The second protrusion 12 also serves as a service hole, and is fastened to the rear floor panel 3 with a plurality of fasteners so as to be opened and closed.

  Both ends of the rear horizontal portion 3e of the rear floor panel 3 in the vehicle width direction are reinforced by reinforcing members 9. Each reinforcing member 9 is coupled to the lower surface of the rear floor panel 3 to form a closed section in cooperation with the rear floor panel 3, and an outer end portion in the vehicle width direction is coupled to the rear side sill 5. Note that the luggage compartment floor panel 4 is formed with a tire accommodating recess 4a (tire pan 4a).

  The fuel tank 8 is disposed below the rear portion of the rear floor panel 3 with respect to the kick-up portion 3 b reinforced by the cross member 6, and a connection port to which a fuel supply pipe is connected to the upper surface side of the fuel tank 8. A member 13 is provided, and the connection port member 13 is disposed facing the service hole 10 that opens upward from the rear floor panel 3.

The fuel tank 8 has a tank upper portion 8a and a tank lower portion 8b made of synthetic resin, and is configured by joining the outer peripheral flange portions 8c to each other. The outer peripheral flange portion 8c is fastened to the bottom surface side of the rear floor panel 3. Further, the fuel tank 8 is fixedly supported by a pair of band members 14 having both ends fastened to the cross member 6 and the reinforcing member 9 by bolts 14a.
Further, a bulging portion 8d bulging upward from the front side is formed on the vehicle rear side of the tank upper portion 8a, and the distance from the central horizontal portion 3c is narrower on the rear side than the front side.
A fuel pump unit (not shown) is accommodated in the right front portion of the fuel tank 8.

As shown in FIG. 4, in a region corresponding to the side of the right bulging portion 8d of the fuel tank 8, a long shape having a thickness of 1.2 mm so as to sandwich the vehicle inner flange 7a of the rear frame 7 with the central horizontal portion 3c. A first protect plate 15 of a steel plate is provided. The first protect plate 15 includes a first extending portion 15a that overlaps the vehicle inner flange 7a, and a first bent portion 15b that extends from the vehicle inner end of the first extending portion 15a and curves upward. ing.
Although the edge of the end portion of the vehicle inner flange 7a faces the vehicle inner side, there is no region that directly faces the right bulging portion 8d of the fuel tank 8 due to the first bent portion 15b.

  As shown in FIG. 6, the first extending portion 15 a is disposed above the upper surface of the fuel tank 8, and the right bulge in which the upper surface of the fuel tank 8 is closer to the flange 7 a than other portions. The length is approximately the same as the longitudinal length of the portion 8d. In the front-rear direction, the first extending portion 15a is gradually curved upward as it goes rearward from the front end, and in the vehicle width direction, it extends from the outer end region of the flange 7a beyond the inner end portion. Furthermore, it extends substantially flat from the side wall of the tank upper portion 8a to the vehicle inner side.

  The first bent portion 15b is curved from the vehicle inner end portion of the first extending portion 15a toward the first projecting portion 11 of the central horizontal portion 3c, and covers the flange 7a and the tip of the first bent portion 15b. Is configured to be accommodated in a space directly below the first protrusion 11. The first bent portion 15b is also located above the upper surface of the fuel tank 8 and inside the vehicle from the side wall of the tank upper portion 8a.

  As shown in FIG. 5, in a region corresponding to the side of the left bulging portion 8e of the fuel tank 8, a long shape having a thickness of 1.2 mm so that the vehicle inner flange 7a of the rear frame 7 is sandwiched between the central horizontal portion 3c. A second protect plate 16 made of a steel plate is provided. Similar to the first protect plate 15, the second protect plate 16 has a second extending portion 16a that overlaps the vehicle inner flange 7a, and extends from the vehicle inner end of the second extending portion 16a and curves upward. It is comprised from the 2nd bending part 16b.

  As shown in FIG. 7, the second extending portion 16a is disposed above the upper surface of the fuel tank 8, and the upper surface of the fuel tank 8 is closer to the flange 7a than other portions. The length is approximately the same as the longitudinal length of the portion 8e. It is substantially flat in the front-rear direction, and extends in the vehicle width direction so as to extend from the outer end region of the flange 7a to the inner end, and further to the vehicle inner side than the side wall of the tank upper portion 8a. ing.

  The second bent portion 16b is curved from the vehicle inner end portion of the second extending portion 16a toward the second projecting portion 12 of the central horizontal portion 3c, and covers the flange 7a and the tip of the second bent portion 16b. Is configured to be accommodated in a space immediately below the second protrusion 12. The second bent portion 16b is also located above the upper surface of the fuel tank 8 and inside the vehicle from the side wall of the tank upper portion 8a. The first and second protect plates 15 and 16 are joined to each other by so-called triple welding of the rear floor panel 3 and the flange 7a.

Next, the behavior of the protect plate at the time of a vehicle collision will be described.
When the right rear portion of the vehicle collides, the side frame 7 is deformed toward the inside of the vehicle. At this time, the flange 7a is also deformed toward the inside of the vehicle as the side frame 7 is deformed.
When the side frame 7 moves in the horizontal direction, the flange 7a covered with the first protect plate 15 is located above the upper surface of the fuel tank 8, so that the fuel tank 8 is damaged by the edge of the end of the flange 7a. Can be prevented.
The same applies when the side frame 7 moves upward due to a collision.

When the side frame 7 moves downward, the end of the flange 7a is covered with the first protect plate 15, so that the fuel tank 8 is not damaged by the edge of the end of the flange 7a.
Further, since the first bent portion 15b is curved from the vehicle inner end portion of the first extending portion 15a toward the first projecting portion 11 of the central horizontal portion 3c, the first bent portion 15b is the upper surface of the fuel tank 8. Alternatively, it is possible to make surface contact with the curved portion of the upper surface and the side wall, and it is possible to prevent the fuel tank 8 from being damaged by the vehicle inner end portion of the first protect plate 15 itself.

Further, even if the contact between the first bent portion 15b and the fuel tank 8 proceeds, the first protect plate 15 is thin, and the tip of the first bent portion 15b is located in the space immediately below the first projecting portion 11. Since it is configured to be accommodated, the first protect plate 15 can be positively deformed, and an excessive load is not applied to the fuel tank 8.
In addition, since it is not necessary to form an additional portion on the frame member while preventing the fuel tank 8 from being damaged, it is possible to improve the yield.
It should be noted that the behavior on the right side is the same when the left rear part is collided.

Next, a modification in which the above embodiment is partially changed will be described.
In the above embodiment, an example in which protect plates are installed on the flange portions of the left and right side frames has been described, but the invention is not limited to the left and right sides. It is also possible to install one end, and it is also possible to install only one end with particularly severe impact characteristics.

2] In the above embodiment, the flange covered with the protect plate is positioned above the upper surface of the fuel tank. However, the present invention is not limited to this layout. It is possible to prevent damage.

3] In the above embodiment, the protect plate is a thin metal plate, but is not limited to the metal plate, and the thickness and material can be selected from the viewpoint of deformation characteristics and cost.

  In addition, those skilled in the art can implement the present invention by adding various modifications without departing from the spirit of the present invention, and the present invention includes such modifications.

It is a top view of the rear part body structure concerning the example of the present invention. It is the II-II sectional view taken on the line of FIG. It is a bottom view of the rear vehicle body structure of FIG. It is a principal part enlarged view of the vehicle body right side. It is a principal part enlarged view of the vehicle body left side. It is the perspective view which removed the rear floor panel in FIG. It is the perspective view which removed the rear floor panel in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower vehicle body structure 3 Floor panel 3c Center horizontal part 4 Refueling opening 7 Rear frame 7a Flange part 8 Fuel tank 11 1st protrusion part 12 2nd protrusion part 15 1st protection plate 15a 1st extension part 15b 1st curve Portion 16 second protect plate 16a second extending portion 16b second bent portion

Claims (5)

A fuel tank disposed below the floor panel of the vehicle body; and a frame member of the vehicle body disposed near the fuel tank and joined to the lower surface of the floor panel by a joint flange portion; In the lower body structure provided with an end projecting toward the fuel tank,
A protective plate is provided between the joining flange and the fuel tank to cover the end of the joining flange,
The protect plate is joined to the flange portion and extends to the fuel tank side,
A bent portion which is provided at the end of the extended portion on the fuel tank side and is bent upward;
A lower body structure characterized by comprising:   2. The lower body structure according to claim 1, wherein a projecting portion projecting upward is provided at a position near the joint flange portion of the floor panel, and an end portion of the bent portion of the protect plate is accommodated inside the projecting portion. .   The lower body structure according to claim 1 or 2, wherein the protect plate is provided only at a predetermined portion where the joining flange portion and the fuel tank are close to each other.   The lower vehicle body structure according to claim 1, wherein a thickness of the protection plate is made thinner than a thickness of the frame member. The lower body structure according to claim 1, wherein the protect plate, the joining flange portion, and the floor panel are welded together at the same time.