JPH0450179Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a rear cross member structure of an automobile.

Conventional technology Figures 9 and 10 show the conventional structure.
Reference numeral 2 denotes a rear side member of a strength member in the longitudinal direction of the vehicle body, which is disposed on both sides of the lower surface of the rear floor 1 at the rear of the vehicle body. A fuel tank mounting member 3 is provided astride the rear side members 2 disposed on both sides of the vehicle body, and a rear cross member 4 is provided astride the rear side member 3 behind the fuel tank mounting member 3. Reference numeral 5 designates a fuel tank. The front end of the fuel tank 5 is fixed to the fuel tank mounting member 3 via a bracket 13, and the rear end is fixed to the rear cross member 4 via a bracket 14. A structure similar to this is disclosed in, for example, Japanese Utility Model Application Publication No. 188024/1983.

Problems to be Solved by the Invention In the event of a rear-end collision, the rear cross member 4 may be curved and deformed toward the front of the vehicle body due to the impact force, and may interfere with the fuel tank 5. Therefore, the rear cross member 4
The plate thickness is increased to improve rigidity, suppress deformation of the rear cross member 4 toward the fuel tank 5, and prevent interference between the fuel tank 5 and the rear cross member 4. However, although the rigidity is increased by increasing the plate thickness of the rear cross member 4, the weight of the rear cross member 4 increases, resulting in a problem that the vehicle weight increases. In addition, in order to prevent the rear side wall 12 of the fuel tank 5 from being damaged by a direct hit from a collision object, a protective wall 15 is separately attached to the rear cross member 4 to protect the rear side wall 12 of the fuel tank 5, which further reduces the vehicle weight. will increase.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rear cross member structure for an automobile that can improve the rigidity of the rear cross member without increasing the weight of the vehicle and protect the fuel tank from direct hits from collision objects. .

Means for Solving the Problems The rear cross member is composed of a front member and a rear member that face each other and have a substantially U-shaped cross section,
The front member and the rear member are joined at least at a substantially central portion in the vehicle width direction to form a closed cross-sectional structure, and a vehicle body functional part is attached to the rear side wall of the rear member, and faces the fuel tank of the front member. A step portion extending substantially horizontally is formed in a curved manner at a substantially central portion of the side wall in the vertical direction of the vehicle body, and a retainer is disposed on the inner surface of the step portion, while both front and rear ends of the retainer are brought into contact with the inner surface of the side wall of the front member. The fuel tank is supported by fastening a rear end flange portion formed approximately at the center of the fuel tank in the vertical direction of the vehicle body to the stepped portion.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, with the same reference numerals assigned to the same parts as the conventional configuration.

1 to 5 show a first embodiment of the present invention, in which a rear side member 2 of a strength member in the longitudinal direction of the vehicle body is disposed on both sides of the lower surface of a rear floor 1 at the rear of the vehicle body.
A fuel tank mounting member 3 is provided astride the fuel tank mounting member 3, and a rear cross member 4 is provided astride the fuel tank mounting member 3. The basic structure in which the front end of the fuel tank 5 is fixed to the fuel tank mounting member 3 and the rear end of the fuel tank 5 is fixed to the rear cross member 4 is the same as that of the conventional example.

Here, the rear cross member 4 is composed of a front member 4a and a rear member 4b having a substantially U-shaped cross section and facing each other, and the front member 4a and the rear member 4b are joined at a substantially central portion in the vehicle width direction to have a closed cross-sectional structure. is formed. A substantially step-like stepped portion extending substantially horizontally is provided at substantially the center portion of the side wall 7 of the front member 4a facing the fuel tank 5 in the vehicle width direction and substantially at the center portion in the vertical direction of the vehicle body. 8 is bent and formed to form this stepped portion 8.
A retainer 4c for attaching the fuel tank 5 is disposed on the inner surface of the retainer 4c, and both front and rear ends 4 of the retainer 4c
e and 4f are extended so as to come into contact with the inner surfaces of the upper and lower side walls 7a and 7b in the figure among the side walls 7 of the front member 4a. Then, a rear end flange portion 9 formed at approximately the center of the fuel tank 5 in the vertical direction of the vehicle body is attached to this stepped portion 8 with bolts. Natsu 10
The fuel tank 5 is supported by being tightened with. On the other hand, both ends of the rear cross member 4 are
The rear member 4b extends linearly in the vehicle width direction and is fixed to the rear side member 2, and the front member 4b is fixed to the rear side member 2.
A is bent obliquely toward the front of the vehicle body and is fixed to the rear side member 2. A tow hook 16 and the like as functional parts of the vehicle body are attached to the rear side wall 7c of the rear side member 4b with attachment bolts 17. Note that 4d is a reinforcing plate for attaching the tow hook 16 and the like. In Figures 4 and 5, 1
1 is the fuel tank mounting step part 3 of the rear cross member 4
It is a drainage groove that is bent and formed at an appropriate part of the
This water drain groove 11 drains water that has entered between the rear side wall 12 and rear end flange portion 9 of the fuel tank 5 and the rear cross member 4, and drains the water that has entered the fuel tank 5.
Rust on the mounting part is prevented.

According to the above embodiment structure, the rear end flange portion 9 of the fuel tank 5 is located at the substantially central portion in the vehicle width direction of the side wall 7 of the front member 4a facing the fuel tank 5.
In addition, since the fuel tank 5 is fastened to a stepped portion 8 bent at approximately the center in the vertical direction of the vehicle body, the rear side wall 12 of the fuel tank 5 is covered by the side wall 7 of the front member 4a facing the fuel tank 5. Therefore, in the event of a rear collision, the rear cross member 4 functions as a protective wall for the fuel tank 5, so that the fuel tank 5 is not damaged by being directly hit by the collision object. Further, the front member 4a of the rear cross member 4 has both ends bent toward the front side of the vehicle body, and is connected to the rear side member 2.
, the bending rigidity of the rear cross member 4 in the longitudinal direction of the vehicle body is improved. Therefore, even if the rear cross member 4 receives a collision force in a rear collision, deformation of the rear cross member 4 toward the front of the vehicle body is suppressed, and interference between the rear cross member 4 and the fuel tank 5 is prevented. Furthermore, the extension portion of the front and rear ends 4e and 4f of the retainer 4c allows the towing hook 16 attached to the rear member 4d to be attached to the rear member 4d.
This prevents the mounting bolts 17 such as the above from thrusting into the front member 4a and damaging the fuel tank 5 in the event of a rear collision.

FIG. 6 shows a second embodiment of the present invention, in which both ends of a front member 4a of a rear cross member 4 extend linearly in the vehicle width direction and are fixed to the rear side members 2, and both ends of a rear member 4b The second embodiment is the same as the first embodiment except that it is bent obliquely toward the rear of the vehicle body and is fixed to the rear side member 2. With the configuration of this embodiment as well, the bending rigidity of the rear cross member 4 in the longitudinal direction of the vehicle body can be improved in the same manner as in the first embodiment.

FIG. 7 shows a third embodiment of the present invention, in which both ends of a front member 4a of a rear cross member 4 are bent obliquely toward the front of the vehicle body and fixed to the rear side members 2, and both ends of a rear member 4b are bent obliquely toward the front of the vehicle body. It is the same as the first embodiment except that it is bent obliquely toward the rear of the vehicle body and is fixed to the rear side member 2. Also with the configuration of this embodiment, the rigidity of the rear cross member 4 can be improved in the same way as in the first and second embodiments.

Further, as shown in FIG. 8, the stepped portion 8 may be formed upward.

Effects of the invention As described above, according to the invention, the side wall of the front member facing the fuel tank is bent at approximately the center in the vertical direction of the vehicle body, and both front and rear ends are formed on the inner surface of the front member. The rear end flange portion of the fuel tank formed at approximately the center in the vertical direction of the vehicle body is fastened to the stepped portion where the extended retainer is disposed so that the rear side wall of the fuel tank is in contact with the fuel of the front member. It is covered by a side wall with a retainer on the inner surface facing the tank. Therefore, there is no need to increase the thickness of the rear cross member to improve its rigidity or install a separate protective wall to cover the rear side wall of the fuel tank.
This has a great practical effect in that damage to the fuel tank in the event of a rear collision can be prevented without increasing the weight of the vehicle, and the weight of the vehicle body can be reduced and safety can be further improved.

[Brief explanation of the drawing]

Figure 1 is a bottom view of the rear floor showing the first embodiment of the present invention, Figure 2 is a cross-sectional view of Figure 1;
The figure is a sectional view taken from FIG. 1, FIG. 4 is a sectional view taken from FIG. 1, FIG. 5 is a view of the rear cross member shown in FIG. 8 is a sectional view showing another embodiment equivalent to FIG. 2, and FIG. 9 is a bottom view of the rear floor showing a conventional example.
FIG. 10 is a cross-sectional view of FIG. 9. 2... Rear side member, 4... Rear cross member, 4a... Front member, 4b... Rear member, 5... Fuel tank, 8... Fuel tank mounting step portion, 9... Rear end flange portion.

Claims (1)

[Scope of utility model registration request] In a structure in which a rear cross member spanning rear side members on both sides of the vehicle body is disposed behind a fuel tank set at the rear of the vehicle body, and the rear end portion of the fuel tank is supported by the rear cross member, the rear cross member It is composed of a front member and a rear member which have a substantially U-shaped cross section and whose members face each other.
The front member and the rear member are joined at least at a substantially central portion in the vehicle width direction to form a closed cross-sectional structure, and a vehicle body functional part is attached to the rear side wall of the rear member, and faces the fuel tank of the front member. A step portion extending substantially horizontally is formed in a curved manner at a substantially central portion of the side wall in the vertical direction of the vehicle body, and a retainer is disposed on the inner surface of the step portion, while both front and rear ends of the retainer are brought into contact with the inner surface of the side wall of the front member. A rear cross member for an automobile, characterized in that the fuel tank is supported by tightening a rear end flange portion formed at a substantially central portion of the fuel tank in the vertical direction of the vehicle body to the stepped portion. structure.