JPH04310482A - Rear under body structure - Google Patents

Abstract

PURPOSE:To improve the rigidity in the periphery of a rear axle for supporting a fuel tank, to improve the productivity of a rear floor pan and to improve the dimensional accuracy. CONSTITUTION:A fuel tan 24 is disposed in the rear of a seat back 40 of a rear seat 30, and a fuel tank 24 is disposed under a rear floor pan 26 on the substantially same straight line as a rear axle 18. The front and rear and right and left portions of the fuel tank 24 are surrounded with a sub-frame 52 formed like a cube, and the rear portion of the sub-frame 52 is supported by a cross- member 36. A rear floor pan 26 is divided into the front portion 28 and the rear portion 32 at a part corresponding to the rear longitudinal wall portion of the fuel tank 24, and the front portion 28 and the rear portion 32 of the rear floor pan 24 are connected to each other through a cross-member 36.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear underbody structure for an automobile, and more particularly to a rear underbody structure provided with a fuel tank.

0002

2. Description of the Related Art Conventionally, as an example of the rear underbody structure of an automobile, as shown in FIG.
2, and the bottom of the fuel tank 82 is fixed to a mounting member 86 arranged at substantially the same height as the floor pan 84 (Japanese Utility Model Publication No. 2-105023).

However, in this rear underbody structure, the rear axle 8 is located at the rear of the fuel tank 82.
8 is located, and the support member 8 of the fuel tank 82
6 does not have a structure that directly improves the rigidity of the rear underbody structure around the rear axle 88. Therefore,
There has been a problem in that when an excessive load is applied to the rear underbody from the rear suspension or the like, the amount of deformation of the rear underbody increases.

[0004] As a rear underbody structure for a front-engine, front-drive vehicle that improves this problem, the rear floor pan is formed to protrude upward in the vertical direction of the vehicle body at the upper part of the rear axle behind the seat back, and a protrusion is formed within this protrusion. The applicant has proposed a rear underbody structure for an automobile in which a fuel tank is arranged substantially in line with the rear axle.

[0005]

[Problems to be Solved by the Invention] However, in this rear underbody structure, the cross-sectional shape of the protruding portion of the floor pan that covers the fuel tank when viewed from the vehicle width direction is in an inverted U-shape. Therefore, when the protruding portion of the floor pan is integrally formed by press working, deep drawing is required, which has the disadvantage of poor productivity and reduced dimensional accuracy.

[0006] Taking the above facts into consideration, the present invention can improve the rigidity around the rear axle that supports the fuel tank, as well as improve the productivity and dimensional accuracy of the rear floor pan. The purpose is to obtain a rear underbody structure.

[0007]

[Means for Solving the Problems] The invention as claimed in claim 1 is a rear underbody structure of a front engine front drive vehicle, in which a rear axle which is located behind a seat back and connects axles of left and right wheels is provided. A fuel tank arranged on the same straight line, a well-shaped subframe that surrounds the front, rear, left, and right sides of the fuel tank, and covers the fuel tank from above in the vertical direction of the vehicle body and corresponds to the rear vertical wall of the fuel tank. a rear floor pan that is divided into a front part in the longitudinal direction of the vehicle body and a rear part in the longitudinal direction of the vehicle body; and a cross member that supports the rear part of the subframe;
It is characterized by having the following.

[0008]

According to the invention as set forth in claim 1, the rear floor pan is divided into a front side portion in the longitudinal direction of the vehicle body and a rear side portion in the longitudinal direction of the vehicle body at a portion corresponding to the rear vertical wall portion of the fuel tank. When forming the part covering the tank by press working, there is no need to perform deep drawing. Therefore, productivity of the rear floor pan can be improved, and dimensional accuracy can also be improved. Also,
The front side of the rear floor pan in the longitudinal direction of the vehicle body and the rear side in the longitudinal direction of the vehicle body are connected via a cross member. is supported. Therefore, the rigidity around the rear axle that supports the fuel tank can be improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a rear underbody structure according to the present invention will be described with reference to FIGS. 1 to 3.

In the figure, arrow FR indicates the forward direction of the vehicle body, and arrow UP indicates the upward direction of the vehicle body. As shown in FIG. 3, at both ends in the vehicle width direction of the rear underbody 10 of a front engine front drive vehicle, a rear floor side member light 14 and a rear floor side member left 16 are provided substantially parallel to each other in the longitudinal direction of the vehicle body. It is being

As shown in FIG. 2, the rear floor side member light 14 and the rear floor side member left 16 each have a U-shaped cross section with their openings facing outward in the vehicle width direction. The rear floor side member lefts 16 are respectively arranged above the rear axle 18.

As shown in FIG. 3, the front part 14A of the rear floor side member light 14 is curved outward and downward in the vehicle width direction, and its front end is connected to the rocker light 18.
It is welded to the rear end of the vehicle from the inside in the vehicle width direction. Further, the front part 16A of the rear floor side member left 16 is curved outward and downward in the vehicle width direction, and the front end thereof is
It is welded to the rear end of the rocker left 20 from the inside in the vehicle width direction. Front part 14 of rear floor side member light 14
A and the front part 16A of the rear floor side member left 16
A block-shaped fuel tank 24, which is elongated in the vehicle width direction, is arranged between the rear axle 18 and the rear axle 18.

As shown in FIG. 2, a rear floor pan 26 is disposed between the rear floor side member right 14 and the rear floor side member left 16.

As shown in FIG. 1, the rear floor pan 26
is divided into two parts, a front part 28 and a rear part 32. A front portion 28 of the rear floor pan 26 constitutes a cabin floor, and a seat cushion 38 of a rear seat 30 is disposed therein. The rear part of the front part 28 of the rear floor pan 26 is curved upward in the vertical direction of the vehicle along the upper part of the fuel tank 24, and the rear end is bent toward the rear in the longitudinal direction of the vehicle, so that the upper surface of the fuel tank 24 horizontal part 28A that covers
It is said that

The rear part 32 of the rear floor pan 26 is used as a storage area for a spare tire 34.
The front end of the rear part 32 is close to the rear part of the fuel tank 24. A cross member 36 is disposed between the horizontal portion 28A of the front portion 28 of the rear floor pan 26 and the front end of the rear portion 32 of the rear floor pan 26. This cross member 36 is arranged along the rear wall of the fuel tank 24, and its upper end is bent forward in the longitudinal direction of the vehicle body to form a flange 36A.
A is welded to the rear end of the horizontal portion 28A of the rear floor pan 26 from above in the vertical direction of the vehicle body. A stepped portion 36B that slightly protrudes toward the rear in the longitudinal direction of the vehicle body is formed at approximately the center of the cross member 36 in the vertical direction of the vehicle body. Welded from above.

The lower part of the stepped portion 36B of the cross member 36 is
It is bent toward the rear side in the longitudinal direction of the vehicle body, and has a U-shaped cross section 37 with an opening facing upward in the vertical direction of the vehicle body. The upper end of the rear wall 37A of this U-shaped cross section 37 is bent rearward in the longitudinal direction of the vehicle body to form a flange 37B.
2 from the bottom in the vertical direction of the vehicle body.

As shown in FIG. 2, the rear floor pan 26
Both end portions in the vehicle width direction of the horizontal portion 28A of the front portion 28 are welded to the upper wall portion 14B of the rear floor side member right 14 and the upper wall portion 16B of the rear floor side member left 16, respectively. Further, both ends of the upper part of the cross member 36 in the vehicle width direction are connected to the rear floor side member lights 1, respectively.
4 and the vehicle widthwise inner wall 16C of the rear floor side member left 16. Further, both ends in the vehicle width direction of the rear part 32 of the rear floor pan 26 are welded to the lower wall part 14D of the rear floor side member light 14 and the lower wall part 16D of the rear floor side member left 16, respectively. There is.

Therefore, the middle portion 36 of the rear floor pan 26
The front vertical wall portion 36A and the rear vertical wall portion 36B respectively connect the rear floor side member right 14 and the rear floor side member left 16 in a bulkhead shape.

As shown in FIG. 3, the fuel tank 2
4, a square-shaped rear subframe 52 is disposed substantially horizontally below the rear floor pan 26 in the vehicle body vertical direction when viewed from above. The front part of this rear subframe 52 is a front cross member 52A having a closed cross-section structure extending in the vehicle width direction.
The rear portion of No. 2 is a rear cross member 52B having a closed cross-section structure extending in the vehicle width direction. Rear subframe 5
The right side in the vehicle width direction of No. 2 is a light side member 52C having a closed cross-section structure extending in the longitudinal direction of the vehicle body along the front portion 14A of the rear floor side member light 14.
The left side portion of the rear subframe 52 in the vehicle width direction is a left side member 5 having a closed cross-sectional structure extending in the longitudinal direction of the vehicle body along the front portion 16A of the rear floor side member left 16.
It is considered 2D.

As shown in FIGS. 1 and 3, a bracket light front 54 is provided on the inner side in the vehicle width direction near the front end of the front portion 14A of the rear floor side member light 14. The front end of the light side member 52C of the rear subframe 52 is attached from below in the vertical direction of the vehicle via a mount (not shown). Further, on the inner side in the vehicle width direction near the front end of the front part 16A of the rear floor side member left 16,
A bracket left front 56 is provided, and the front end portion of the left side member 52D of the rear subframe 52 is attached to the bracket left front 56 from below in the vertical direction of the vehicle body via a mount (not shown).

A bracket light rear 58 is provided at the lower part of the front part 14A of the rear floor side member light 14 near the rear end.
A rear end portion of the light side member 52C of the rear subframe 52 is attached to the bracket light rear 58 from below in the vertical direction of the vehicle body via a mount (not shown). Further, a bracket left rear 59 is provided at the lower part near the rear end of the front part 16A of the rear floor side member left 16, and this bracket left rear 59 has a left side member of the rear subframe 52. The rear end portion of 52D is attached to the vehicle body from below in the vertical direction via a mount (not shown).

Next, the operation of this embodiment will be explained. In this embodiment with the above configuration, the rear floor pan 26 is divided into a front part 28 and a rear part 32 at a portion corresponding to the rear vertical wall of the fuel tank 24, so the part of the rear floor pan 24 that covers the fuel tank 24 is pressed. There is no need to perform deep drawing when forming. Therefore,
The productivity of the rear floor pan 24 can be improved and the dimensional accuracy can also be improved, and when a galvanized steel plate is used, the zinc is not peeled off during deep drawing. In addition, the front part 2 of the rear floor pan 24
8 and the rear part 32 are connected via a cross member 36, and this cross member 36 includes a rear subframe 5.
The rear of 2 is supported. Therefore, rear floor pan 2
The rigidity of the joint between the front part 28 and the rear part 32 of the fuel tank 6 can be sufficiently ensured, and the rigidity around the rear axle 18 that supports the fuel tank 24 can be improved.

Furthermore, in this embodiment, the thickness of the cross member 36 can be different from that of the rear floor pan 26, so the degree of freedom in selecting the thickness of the cross member 36 is improved. Therefore, the joint rigidity between the rear floor side member right 14 and the rear floor side member left 16 can be optimized by changing the plate thickness of the cross member 36. Furthermore, in the present embodiment, the closed cross section of the cross member, which in the conventional structure is arranged at the front side of the spare tire accommodating part in the longitudinal direction of the vehicle body, is replaced with the rear floor pan 26 that constitutes the spare tire accommodating part.
Since the spare tire 34 is placed below the rear part 32 of the vehicle, the spare tire 34 can be placed further forward of the vehicle body, the rear overhang of the vehicle body can be shortened, and the degree of freedom in designing the exterior shape of the vehicle body can be improved.

[0024]

[Effects of the Invention] Since the present invention has the above structure, it is possible to improve the rigidity around the rear axle that supports the fuel tank, and also to improve the productivity and dimensional accuracy of the rear floor pan. It has the excellent effect of being able to

[Brief explanation of drawings]

FIG. 1 is a side view showing a rear underbody structure according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line 2-2 in FIG. 1;

FIG. 3 is a plan view showing the rear underbody structure of the embodiment of the present invention.

FIG. 4 is a side view showing a conventional rear underbody structure.

[Explanation of symbols]

10 Rear underbody 18 Rear axle 24 Fuel tank 26 Rear floor pan 28 Front part 32 Rear 36 Cross member 30 Rear seat 40 Seat back 52 Subframe

Claims (1)

[Claims] Claim 1: A rear underbody structure of a front-engine, front-drive vehicle, comprising: a fuel tank disposed on the rear side of a seat back and approximately on the same line as a rear axle connecting the axles of left and right wheels; A well-shaped sub-frame surrounds the front, rear, left and right sides of the tank, and covers the fuel tank from above in the vertical direction of the vehicle, and also includes a sub-frame in the front and rear of the vehicle in the front and back directions of the vehicle at a portion corresponding to the rear vertical wall of the fuel tank. a cross member disposed in the divided portion of the rear floor pan, which connects the front side portion in the longitudinal direction of the vehicle body and the rear side portion in the longitudinal direction of the vehicle body, and supports the rear portion of the subframe; The rear underbody structure is characterized by the following.