JPS6141789B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automobile body structure, and particularly to a rear body structure by improving the mounting portion of a rear wheel suspension system.

In the body structure of an automobile, a particularly large load is applied to the portion where the wheel suspension device is attached, so it is necessary to increase the strength of this attachment portion.
In particular, since the rear wheel suspension system is attached below the floor of the vehicle body, it is necessary to reinforce this portion of the floor. Conventionally, various floor structures have been known in which the mounting portion of the rear wheel suspension system is reinforced. However, simply adding reinforcing members to reinforce the floor or adding complicated processing to the floor components increases the weight of the vehicle body, making it difficult to drive, and increases the cost of materials and manufacturing process. Because of the increased costs and manufacturing disadvantages involved in this process, it is desirable to strengthen the floor portions in a manner that does not require significant additions to materials or processes.

Therefore, for example, as disclosed in Japanese Utility Model Application No. 54-59622, a rear side member is attached to a side sill with a strong closed cross-section structure, and is fixed to the bottom of the floor so as to form a closed cross section between the side sill and the floor. A structure has been proposed in which a rear wheel suspension device is attached to the bottom of a rear side member which is joined together and whose strength is increased by this joining. This structure is advantageous in terms of strength because the load on the suspension system is received by the closed-section rear side member under the floor, and this load is shared by the closed-section side sill, and it also does not use extra materials. It is also superior in terms of cost. However, because the only thing that transmits the load on the rear side member to the side sill is the bond between the side edge of the rear side member and the inner surface of the side sill inner, there is a risk that this bond may separate when a large load is applied to the rear side member. Therefore, it cannot be said that it has sufficient strength for practical use.

The object of the present invention is to improve this point, further improve the strength of this portion at low cost, and provide a rear vehicle body structure with sufficient strength for practical use.

In the rear vehicle body structure of the present invention, a part of the side sill inner is extended into the rear side member at a portion where the rear side member is fixed to the side sill having a closed cross-section structure with high strength, and this extended portion and the bottom surface of the rear side member are connected to each other. are overlapped to form a double bracket fixing part, and a bracket for mounting the rear wheel suspension system is fixed to this bracket fixing part, and the edge of the rear side member is bent downward, and this bent part is fixed to the bracket fixing part. It is characterized in that it is fixed to the side sill inner and side sill outer so that these three members form a closed cross section of the rear part of the side sill.

In this way, a part of the side sill inner is extended into the rear side member, and this extended part is overlapped with the bottom surface of the rear side member to form a double bracket fixing part. The rigidity of the part where the bracket is directly fixed is increased, and since the edge of the rear side member is bent downward and fixed to the side sill inner and side sill outer, the bonding strength between the rear side member and the side sill is increased, and the suspension system applied to the rear side member is increased. Since the load from the rear body is not concentrated locally but is dispersed to each of the fixed parts, the load is transmitted smoothly, and the rear body structure as a whole is resistant to large loads and shocks.

Embodiments of the vehicle body structure of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a perspective view showing the main parts of the rear body of an automobile including the rear body structure of the present invention.

The floor 1 of the rear vehicle body is composed of a center floor panel 11 located at a low position, and a rear floor panel 12 provided at a high position with a step behind the center floor panel 11. The rear floor panel 12 extends in the left-right direction of the vehicle body, and includes a cross member 2 that forms a closed cross section with the lower surface of the rear floor panel 12, and a cross member 2 that extends in the front-rear direction of the vehicle body along the lower surface of the side edge of the rear floor panel 12. It is reinforced by the rear side member 3 which forms a closed cross section with the panel 12. A side edge of the center floor panel 11 and a front side edge of the rear floor panel 12 are fixed to a side sill 4 having a closed cross-section structure and extending in the front-rear direction along the side edge of the vehicle body. The side sill 4 is composed of a side sill inner 41 that is directly fixed to the floor 1 and a side sill outer 42 that is fixed to the outside thereof so as to form a closed cross section, and the rear end is connected to the rear tire house 5. A center pillar 6 is connected above the side sill 4, and a side frame 7 having a closed section structure extends rearward from above the center pillar 6 and above the rear tire house 5, reinforcing the sides of the vehicle body. .

The rear side member 3 extends along the side edge of the rear floor panel 12 from the back panel 8 forming the rear wall of the vehicle body to the rear end portion of the side sill 4.
The front end of the rear side member 3 is fixed to the rear end of the side sill inner 41.

This rear side member 3 has a U-shaped cross section,
An inner surface 31 located inside the vehicle body, an outer surface 32 located outward parallel to this inner surface 31, and this inner surface 3
1 and a bottom surface 33 that is connected to the lower edge of the outer surface 32 and extends parallel to the rear floor panel 12. The outer surface 32 extends along the rear tire house 5 and is fixed to the rear end of the side sill inner 41. The front end of the inner surface 31 extends forward from the outer surface 32 and is fixed to the inner surface of the side sill inner 41.

The above rear side member 3 and side sill inner 4
The details of the joint with 1 are shown in FIG. In addition, an exploded view of both members 3 and 41 of this part is shown in FIG.
FIG. 4 shows a cross-sectional view of the bonded state of this part. Furthermore, FIG. 4 shows a trailing arm bush 9 of the rear wheel suspension system and a trailing arm mounting bracket 10 for attaching the trailing arm to the vehicle body. In the figure, 33a indicates a mounting hole for fixing the bracket, and 41a indicates a nut for mounting the bracket.

As shown in FIGS. 2, 3 and 4, the vehicle body structure of the present invention has a substantially triangular extending portion 41A that is bent inward of the vehicle body and extends into the rear side member 3 at the rear of the side sill inner 41. The extending portion 41A is overlapped with the front end portion of the bottom surface 33 of the rear side member 3 to form the fixing portion 34 of the double suspension mounting bracket 10.

Furthermore, the front end of the bottom surface 33 of the rear side member 3 is bent downward to match the surface of the side sill inner 41, and this bent portion 33A is fixed to a part of the side sill inner 41 and the side sill outer 42. It is.

In other words, the extended portion 41A obtained by bending the side sill inner 41 and the rear side member bottom surface 33 are overlapped to form a highly rigid bracket fixing portion 34, thereby increasing the strength of the fixing portion of the bracket 10 and fixing the side sill inner 41 and the rear side member. The bottom surface 33 of the rear side member 3 is increased by increasing the bonding area with the rear side member 3 to increase the bonding strength.
The bent portion 33A obtained by bending the side sill 4 is joined to the side sill 4 to further increase the joint strength of both members.

Therefore, the load applied from the rear wheel suspension system via the trailing arm is easily distributed and transmitted to the rear side member 3 and the side sill 4, and stable and robust support for this load is possible.

As is clear from the above description, the rear body structure of an automobile according to the present invention has an extremely simple structure that greatly improves the strength of the vehicle body against the load from the rear wheel suspension system, and the manufacturing cost is low. Therefore, its practical value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of the rear part of a car body adopting the rear body structure of the present invention, FIG. FIG. 4 is a sectional view of FIG. 2, particularly showing the state in which the trailing arm mounting bracket is attached. 1...floor, 2...cross member, 3...rear side member, 4...side sill, 5...rear tire house, 6...center pillar, 7...side frame,
8... Back panel, 9... Trailing arm bush, 10... Trailing arm mounting bracket, 11... Center floor panel, 12... Rear floor panel, 31... Inner surface of rear side member, 32
...Outer surface of rear side member, 33...Bottom surface of rear side member, 33A...Bending portion of rear side member, 34...Fixing portion of trailing arm mounting bracket, 41...Side sill inner, 41A...Extending portion of side sill inner, 42...Side sill Outer.

Claims (1)

[Scope of Claims] 1. A floor, a side sill fixed to the side edge of the floor, formed in a closed cross-section by an inner side sill and an outer side sill, and extending in the longitudinal direction of the vehicle body; fixed to the lower side of the floor; An automobile comprising: a rear side member forming a closed cross-sectional space extending in the front-rear direction of the vehicle body between the rear side member and the floor; and a bracket for mounting a rear wheel suspension device fixed near a connecting portion between the rear side member and the side sill. In the rear vehicle body structure, a part of the side sill inner extends into the rear side member, and the extended part and the bottom surface of the rear side member overlap to form a fixing part of the mounting bracket, and the rear side member The end edge of the rear side member is bent downward, and this bent portion is fixed to the side sill inner and side sill outer, so that the bent portion of the rear side member, the side sill inner and the side sill outer form a closed cross section of the rear of the side sill. A rear body structure of an automobile characterized by: