GB2080211A

GB2080211A - Underbody structure for automotive vehicles

Info

Publication number: GB2080211A
Application number: GB8117483A
Authority: GB
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1980-07-02
Filing date: 1981-06-08
Publication date: 1982-02-03
Also published as: JPS5715769U; FR2486010B1; JPS6219488Y2; DE3122531A1; FR2486010A1

Abstract

The underbody structure comprises a side sill (42) along each side of the underbody between the front and rear wheel locations. A floor panel (44) has an upstanding and transversely extending wall (48) which interconnects the sills (42). A side member (50) extends longitudinally from an end (46) of the underbody to the upstanding wall (48). The side member (50) is provided with an end section (52) which is secured to the upstanding wall (48) and to the side sill (42). <IMAGE>

Description

SPECIFICATION Underbody structure for automotive vehicles The present invention relates in general to vehicle body constructions and more particularly to an underbody structure for an automotive vehicle which is improved in rigidity or stiffness without using any additional part.

Figs. 1 and 2 show a prior art underbody structure for an automotive vehicle. In Fig. 1, the front section of the underbody is shown on the left, while the rear section is shown on the right. Since the front and rear sections of the underbody are substantially similar to each other and particularly since both sections are similar with respect to the structure for connecting an end of a side member to an adjacent structural part or parts, the description will hereinbelow be made mainly to the rear section of the underbody for brevity.

Referring to Figs. 1 and 2, a pair of parallel side members 10 are positioned adjacent the respective lateral sides of the underbody and extend longitudinally from the rear end 1 2 of the underbody to the middle section of same.

The side members 10 each has at the upper portion thereof flanges 14 and are secured at the flanges to the lower surface 1 6 of a rear floor panel 1 8. Each of the side members 10 also has an end 20 on the underbody middle section side and secured at the end 20 to an upstanding and transversely extending wall 22 of the rear floor panel 1 8. The upstanding wall 22 is secured at each lateral end 24 thereof to a side sill 26 or more specifically to the exterior surface 28 of a side sill inner 30 and at the lower end 29 to a front floor panel 31. The rear floor panel 1 8 has, at each lateral side thereof adjacent the upstanding wall 22, a lateral end section 32 and is also secured at the lateral end section 32 to the upper exterior surface 34 of the side sill inner 30.The side members 10 are used for the purpose of reinforcing the floor panel 1 8 and therefore the entire underbody as well as for the purpose of rigidly supporting, at a location adjacent a wheel arch section 36 of the underbody and by way of a link bracket 38, a rear suspension locating rod 40.

The foregoing prior art underbody structure encounters the drawback that vibrations of the underbody, or the permanent deformation of the upstanding wall 22, easily results.

It is found by experiment that the drawback results from the fact that the end 20 of each side member 10 is secured only to the upstanding wall 22 of the floor panel 1 8 and not directly to any highly rigid member.

That is, due to the above fact, there can occur such cases in which while the side member 10 is rigid enough to withstand the force applied thereto from the rear suspension locating rod 40 or from a bumper 41 mounted on the side members in the event of collision, the floor panel 1 8 cannot withstand the force applied thereto from the side member 10, particularly when the side member is subjected to a relatively large longitudinal force.

In accordance with the present invention, there is provided an improved underbody structure for an automotive vehicle. The underbody structure comprises a side sill along each side of the underbody between the front and rear wheel locations. A floor panel has an upstanding and transversely extending wall which interconnects the sills. A side member extends longitudinally from an end of the underbody to the upstanding wall. The side member is provided with an end section which is directly connected to the upstanding wall and to the sill.

With the above structure, the side member is enabled to efficiently reinforce the floor panel. The present invention therefore makes it possible to improve the underbody in rigidity or stiffness without using any additional reinforcement member.

It is accordingly an object of the present invention to provide an improved underbody structure for an automotive vehicle which is improved in rigidity without using any additional part.

In the accompanying drawings: Figure 1 is a plan view of a prior art underbody structure for an automotive vehicle with which the present invention is particularly concerned; Figure 2 is a fragmentary perspective view, on an enlarged scale, of the underbody structure of Fig. 1; Figure 3 is a plan view of the rear section of an underbody structure for an automotive vehicle according to an embodiment of the present invention; Figure 4 is a fragmentary perspective view, on an enlarged scale, of the underbody structure of Fig. 3; and Figure 5 is a view similar to Fig. 4 but showing another embodiment of the present invention.

Referring first to Figs. 3 and 4, the underbody structure according to an embodiment of the present invention comprises a side sill 42 along each lateral side of the underbody between the front and rear wheel locations. A rear floor panel 44 extends from a rear end 46 of the underbody to the middle section of same and has at a longitudinal end on the underbody middle section side an upstanding and transversely extending wall 48 which interconnects the sills 42. A pair of side members 50 are arranged to extend from the underbody rear end 46 to the upstanding wall 48. Each side member 50 has an end section 52 which is secured directly to the upstanding wall 48 and to the side sill 42.More specifically, the side member 50 is bent in a manner to allow the side member end section 52 to extend longitudinally and laterally outward from the remaining section 54 which is substantially parallel to a lateral side of the underbody. The side member 50 is of a channellike section including a pair of parallel legs 56 and a bottom 58. The laterally outward one of the legs 56 has at the terminal end of the side member end sections 52 a longitudinal extension 60 which is directly secured to the exterior surface 62 of a side sill inner 64. The laterally inward one of the legs 56 has at the terminal end of the side member end section 52 an upstanding flange 66 which is directly secured to the upstanding wall 48.The bottom 58 of the side member 50 has at the terminal end of the side member end section 52 a longitudinal extension 68 which is directly secured to the lower end 70 of the upstanding wall 48. The lower end 70 of the upstanding wall 48 is secured to a front floor panel 72. The legs 56 of the side member 48 further have at the respective upper ends thereof flanges 74 which extend substantially the full length of the side member and through which the side member is secured to the lower surface 76 of the rear floor panel 44. The upstanding wall 48 has at each lateral end thereof a flange 77 which is secured together with the extension 60 of the side member leg 56 to the exterior surface 62 of the side sill inner 64. The side member 50 is adapted to rigidly support a rear suspension locating rod 78 by way of a link bracket 80 in a manner similar to the prior art structure.

Also as similar to the prior art structure, the side members 50 have mounted thereon a bumper 79 and the rear floor panel 44 has at each lateral end thereof a lateral end section 81 secured to the side sill inner 64.

With the above structure, it will be understood that the underbody structure of the present invention can obtain an increased rigidity since the end section 52 of the side member 50 is secured to the highly rigid side sill 42 in addition to the upstanding wall 48.

In this connection, it should be noted that the above effect is attained without using any additional structural part.

Fig. 5 shows another embodiment of the present invention. This embodiment is substantially similar to the previous embodiment of Figs. 3 and 4 except that the laterally outward one of the upper end flanges 74 of the side member legs 56 is provided with a lateral extension 82 which is directly secured to the upper exterior surface 84 of the side sill inner 64. The embodiment of Fig. 5 enables the improvement in rigidity to be more assuredly attained.

Claims

1. An underbody structure for an automotive vehicle, comprising a side sill along each side of the underbody between the front the rear wheel locations; a floor panel having an upstanding and transversely extending wall interconnecting said sills; and a side member extending longitudinally from an end of the underbody to said upstanding wall and having an end section directly connected to said upstanding wall and to said sill.

2. An underbody structure as set forth in Claim 1, wherein said side member is bent in a manner to allow said side member end section to extend longitudinally and laterally outward from the remaining section which is substantially parallel to a lateral side of the underbody.

3. An underbody structure as set forth in Claim 1, wherein said side sill includes a side sill inner and wherein said side member is of a channel-like section including a pair of parallel legs and a bottom, one of said legs having at the terminal end of said side member end section an extension which is directly connected to said side sill inner.

4. An underbody structure as set forth in Claim 3, wherein said bottom of said side member has at the terminal end of said side member end section an extension which is directly connected to the lower end of said upstanding wall.

5. An underbody structure as set forth in Claim 3, wherein the other of said legs has at the terminal end of said side member end section an upstanding flange which is directly connected to said upstanding wall.

6. An underbody structure as set forth in Claim 3, wherein said upstanding wall has at each lateral end thereof a flange which is directly connected together with the extension of said one leg to the side sill inner.

7. An underbody structure as set forth in Claim 3, wherein said legs have at the respiective upper ends thereof flanges through which said side member is connected to said floor panel.

8. An underbody structure as set forth in Claim 7, wherein one of said upper end flanges of said legs has a lateral extension which is directly connected to the side sill inner.

9. An underbody structure constructed and arranged substantially as described herein with reference to Figs. 3 and 4, or Fig. 5 of the accompanying drawings.