JP2008265705A - Vehicle rear part structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle rear part structure securely mounting a fuel tank to a vehicle body. <P>SOLUTION: The vehicle rear part structure is provided with: a pair of right and left rear side members 3, 3 provided in a vehicle body rear part and having kick-up parts 9; and with the fuel tank 31 having mounting flanges 35 formed projectingly. By fixing the mounting flanges 35 astride front and rear sides of bend parts 47 formed at the rear ends of the kick-up parts 9, the fuel tank 31 is mounted to the vehicle body. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle rear structure.

  2. Description of the Related Art Conventionally, a technique for dropping a fuel tank mounted on a rear part of a vehicle body when a vehicle has a rear collision is known (see, for example, Patent Document 1).

  In Patent Document 1, a fuel tank module including a substantially cylindrical fuel tank and a fuel tank holding portion that holds the fuel tank and is fixed to the lower surface of the side member is provided. The fuel tank is placed on the fuel tank holding portion, and the fuel tank holding portion is fastened to the side member, whereby the lower portion of the fuel tank is held by the fuel tank holding portion, and both left and right end portions are held by the side member. I am doing so.

When a collision load is input from the rear part of the vehicle, the fuel tank holding part is detached from the side member and falls downward, so that a sufficient load absorption space is ensured at the time of rear collision.
JP 2004-149038 A

  However, in the above-described prior art, the fuel tank is held by the fuel tank holding part, and the constricted part is provided in the fuel tank holding part so that the fuel tank can be detached in response to a rear collision, and the constricted part is aged over time. There was a possibility that it would deteriorate and bend downward.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle rear structure that can securely mount a fuel tank on a vehicle body and absorb energy during a rear collision.

  A vehicle rear portion structure according to the present invention includes a rear side member having a pair of left and right kick-up portions provided at a rear portion of a vehicle body, and a fuel tank having a mounting flange protruding therefrom, and the mounting flange is disposed on the kick-up portion. The most important feature is that the fuel tank is mounted on the vehicle body by fixing it across the front and rear of the bent portion formed at the rear end.

  According to the vehicle rear structure according to the present invention, since the fuel tank is fixed across the bent portion formed at the rear end of the rear side member kick-up portion, the rigidity of the rear end of the rear side member kick-up portion is increased. improves. Therefore, when a collision load is input to the rear part of the vehicle body without deteriorating the holding rigidity of the fuel tank holding part due to deterioration with time, the front end of the kick-up part of the rear side member is bent and deformed to absorb the collision energy. Can do. Further, since it is not necessary to separately provide a mounting member such as a fuel tank holding portion as described in the background art, it is possible to reduce vehicle weight and cost.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 is a perspective view of a rear structure of a vehicle body according to an embodiment of the present invention viewed obliquely from the rear, FIG. 2 is a perspective view showing a fuel tank in FIG. 1, FIG. 3 is a perspective view showing a vehicle body member in FIG. 1 is a side view schematically showing the side of FIG. 1, FIG. 5 is a bottom view schematically showing the lower part of FIG. 1, and FIG. 6 is a cross-sectional view taken along line AA of FIG. is doing.

  As shown in FIGS. 1 and 3, a pair of left and right rear side members 3, 3 are extended from the vehicle body rear portion 1 along the vehicle longitudinal direction. The rear side member 3 is a rectangular tube-shaped vehicle body skeleton member formed hollow inside, and is disposed at a predetermined interval in the vehicle width direction. Specifically, the rear side member 3 includes a front part 7 extending rearward along the lower surface of the floor panel 5, a kickup part 9 extending rearward and obliquely upward from the rear end of the front part 7, and the kickup part 9. The rear part 11 extends substantially parallel to the front part 7 from the rear end.

  A floor panel 5 is disposed at the front portion 7 of the rear side member 3. Specifically, the rear end portion 5 a of the floor panel 5 is mounted on and attached to the front portion 7 of the rear side member 3. A floor tunnel 13 that protrudes upward along the vehicle front-rear direction is formed at the center of the floor panel 5 in the vehicle width direction.

  Further, a suspension member 15 is disposed below the rear side member 3. The suspension member 15 is a U-shaped suspension member main body 17 that connects the rear portions of the rear side member 3, and a connecting body that connects the left and right lower ends of the suspension member main body 17 and the front portions of the suspension member 15. 19. The suspension member main body 17 is integrally formed in a U-shape from a vertical member 21 extending downward from the rear portion of the rear side member 3 and a horizontal member 23 connecting the lower ends of the vertical member 21 to the left and right. A reinforcement 25 is joined to the lower surface of the floor tunnel 13 of the floor panel 5. The reinforcement 25 and the central portion of the lateral member 23 of the suspension member body 17 are bridged by a connecting member 27 along the vehicle longitudinal direction. A differential case 29 (see FIG. 4) that houses a differential gear is disposed below the suspension member 15 across the lower end of the vertical member 21 and the rear end of the horizontal member 23.

  As shown in FIGS. 2, 4, and 5, the fuel tank 31 according to the present embodiment is integrated from a box-shaped fuel tank body 33 and a mounting flange 35 provided on a side surface of the fuel tank body 33. Is formed. The fuel tank main body 33 includes a tank main body front portion 37 having a long vertical length and a tank main body rear portion 39 having a short vertical length. Further, as shown in FIG. 5, the upper surface 37 a and the lower surface 37 b of the tank body front portion 37 are formed in a substantially trapezoidal shape whose length in the vehicle width direction becomes shorter toward the rear of the vehicle. The upper surface 39a and the lower surface 39b are formed in a substantially rectangular shape.

  The mounting flange 35 bends in a letter-like shape from a flange front portion 41 formed on the side surface of the tank body front portion 37 and a flange rear portion 43 formed on the side surface of the tank body rear portion 39. Is formed. The flange front portion 41 extends rearward and obliquely upward along the kick-up portion 9 of the rear side member 3, and the flange rear portion 43 extends along the rear portion 39 of the rear side member 3. Further, as shown in FIGS. 5 and 6, the flange front portion 41 is fastened to the lower surface of the kick-up portion 9 of the rear side member 3 via a bolt 45, and the flange rear portion 43 is connected to the rear portion 11 of the rear side member 3. It is fastened to the lower surface of this via a bolt 45. As described above, the attachment flange 35 of the fuel tank 31 is fixed across the front and rear of the bent portion 47 formed at the rear end of the kick-up portion 9 of the rear side member 3.

  Further, as shown in FIG. 5, a filler tube 49 is routed on the right side surface of the fuel tank 31 through the lower part of the rear side member 3.

  Here, the deformation behavior of the vehicle body rear portion 1 when a collision load is input to the vehicle body rear portion 1 according to the present embodiment will be briefly described. 7 is a side view showing a state where a collision load directed toward the front of the vehicle is input to the rear part of the vehicle body according to the embodiment of the present invention, and FIG. 8 is a side view showing a state where the rear side member of FIG. 7 is deformed.

  First, as shown in FIG. 7, when a collision load F is input to the rear end of the rear side member 3 toward the front of the vehicle, the rear portion of the rear side member 3 is crushed and deformed in the vehicle front-rear direction. Then, a bending moment M is applied in a direction in which the bent portion 47 formed at the rear end of the kick-up portion 9 of the rear side member 3 is to be bent.

  However, since the mounting flange 35 is fixed across the bent portion 47, the bending rigidity of the bent portion 47 is very high. Therefore, a moment m that opposes the bending moment M is generated. Further, the input of the collision load F generates an inertial force I that causes the fuel tank 31 to move rearward relative to the rear side member 3. Then, the moment m is further increased by the inertial force I.

  Therefore, the rear side member 3 is bent and deformed forward of the vehicle, starting from the bent portion 51 formed at the front end of the kick-up portion 9 of the rear side member 3.

  On the other hand, as shown in FIG. 8, in the suspension member 15, the connecting body 19 and the connecting member 27 are bent, and the differential case 29 containing the differential gear is separated from the fuel tank 31.

  Below, the effect by embodiment of this invention is demonstrated.

(1) The vehicle rear structure according to the present embodiment includes rear side members 3 and 3 having a pair of left and right kick-up portions 9 provided on the rear portion 1 of the vehicle body, and a fuel tank 31 having a mounting flange 35 protruding therefrom. By fixing the mounting flange 35 across the front and rear of the bent portion 47 formed at the rear end of the kick-up portion 9, the rigidity of the rear end of the kick-up portion 9 of the rear side member 3 is improved. Therefore, when a collision load is input to the rear part of the vehicle body without deteriorating the holding rigidity of the fuel tank holding part due to deterioration with time, the front end of the kick-up part 9 of the rear side member 3 is bent and deformed, so that the fuel tank It is possible to absorb the collision energy at the front end of the kick-up portion 9 while suppressing the damage. Further, since a mounting member such as a fuel tank holding portion as described in the background art is not required, the weight of the vehicle and the cost can be reduced.

(2) Further, by fixing the mounting flange 35 to the lower surface of the rear side member, the mounting workability of the fuel tank mounted from under the floor is improved.

(3) Further, since the differential gear is disposed behind and below the fuel tank 31, when the rear side member 3 is bent and deformed, the fuel tank 31 moves upward, so that the differential is placed in an empty space below the fuel tank 31. By moving the gear, it is possible to absorb energy in a rear collision while protecting the differential gear.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation and change are possible based on the technical idea of this invention. For example, the attachment flange may be formed by projecting the lower side of the fuel tank side in the vehicle width direction, and the attachment flange may be attached to the side surface of the rear side member.

  FIG. 9 is a cross-sectional view schematically showing a mounting portion of the fuel tank 31 according to another embodiment of the present invention.

  As shown in FIG. 9, the front-rear direction center portion 55 c of the mounting flange 55 provided in the fuel tank 31 is bent and deformed downward, and the front end 55 a and the rear end 55 b of the mounting flange 55 are connected to the lower surface of the rear side member 3 via bolts 45. To conclude. Then, a gap 53 is created between the mounting flange 55 of the fuel tank 31 and the lower surface of the rear side member 3, and the gap 53 is routed through a filler tube 49 connected to the fuel tank 31.

  Therefore, the filler tube 49 can be securely held on the vehicle body member while being protected. Further, since a separate mounting bracket for holding is not necessary, weight reduction and cost reduction can be achieved.

It is the perspective view which looked at the vehicle body rear part structure by embodiment of this invention from diagonally backward. It is a perspective view which shows the fuel tank in FIG. It is a perspective view which shows the vehicle body member in FIG. It is a side view which shows the side surface of FIG. 1 schematically. It is a bottom view which shows the lower part of FIG. 1 schematically. It is sectional drawing by the AA line of FIG. 5, and has arrange | positioned upside down. It is a side view showing the state where the collision load which goes to the vehicle front was inputted into the vehicle body rear part by the embodiment of the present invention. It is a side view which shows the state which the rear side member of FIG. 7 is deform | transforming. It is sectional drawing which shows schematically the attachment part of the fuel tank by other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Car body rear part 3 ... Rear side member 9 ... Kick-up part 31 ... Fuel tank 35 ... Mounting flange

Claims (4)

A rear side member having a kick-up portion provided in a pair of left and right at the rear of the vehicle body;
A fuel tank with a mounting flange protruding therefrom,
A vehicle rear structure, wherein the fuel tank is mounted on a vehicle body by fixing the mounting flange across the front and rear of a bent portion formed at the rear end of the kick-up portion.   The vehicle rear portion structure according to claim 1, wherein the mounting flange is fixed to a lower surface of the rear side member.   The vehicle rear structure according to claim 1, wherein a differential gear is disposed behind and below the fuel tank.   The clearance gap was provided between the attachment flange of the said fuel tank, and the lower surface of a rear side member, and it routed through this filler through the filler tube connected to the said fuel tank. The vehicle rear structure according to the item.

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