GB2139967A

GB2139967A - Floor arrangement for the tail of a motor vehicle

Info

Publication number: GB2139967A
Application number: GB08409378A
Authority: GB
Inventors: Axel Rauthmann
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1983-05-11
Filing date: 1984-04-11
Publication date: 1984-11-21
Also published as: GB8409378D0; FR2545777B1; FR2545777A1; GB2139967B; DE3317180C2; DE3317180A1

Abstract

Longitudinal box girders (3) at the back of the vehicle are interconnected by a cross member overlying the rear axle and a rear cross member 5 and a recess (2) for the spare wheel is formed between the box girders and between the cross members, a fuel tank (6) being disposed partly below the spare wheel recess (2) and partly laterally of the latter. To protect the fuel tank (6) in the event of a side collision, a reinforcing element (8) is disposed below or above the floor plate (1) and extends laterally outwards from the longitudinal girder (3) and overlaps the fuel tank (6). The reinforcing element (8) is preferably corrugated so as to collapse in the event of a rear end collision without offering significant resistance. <IMAGE>

Description

SPECIFICATION Floor arrangement for the tail of a motor vehicle The invention relates to a floor arrangement for the tail of a motor vehicle in which longitudinal box girders at the back of the vehicle are interconnected by a cross member overlying the rear axle and a recess for the spare wheel is formed between the box girders, a fuel tank being disposed partly below the spare wheel recess and partly laterally of the latter.

The invention seeks to provide a floor arrangement of the above type in which the fuel tank is protected not only against rear end collisons but also against side collisions.

According to the present invention, there is provided a floor arrangement for the tail of a motor vehicle in which longitudinal box girders at the back of the vehicle are interconnected by a cross member overlying the rear axle and a rear cross member and a recess for the spare wheel is formed between the box girders and between the cross members, a fuel tank being disposed partly below the spare wheel recess and partly laterally of the latter; wherein a reinforcing element disposed below or above the floor plate extends laterally outwards from the longitudinal girder and overlaps the fuel tank.

Floor arrangements for the tail of a motor vehicle which offer a certain degree of protection of the fuel tank in the event of collision are known, for example from DE OS 23 13588 and DE OS 26 25 268, but these relate to different configurations of the spare wheel recess and fuel tank which because of their poorer utilisation of space are no longer appropriate to modern compact vehicles having a short rear overhang.

Preferably, the reinforcement elements has an undulating cross-section when viewed in a longitudinal section through the vehicle.

In the preferred embodiment of the invention, the reinforcement element protects the part of the fuel tank extending beyond the girder in the event of a side collision in that this reinforcing element acts non-deformably in the direction of the impact in the manner of a girdering strut. In the event of a rear collision, on the other hand, the said reinforcing element does not contribute to the reinforcing action but permits the intended energy dissipation through the controlled deformation of the rear parts of the longitudinal girder or of the floor plate and the spare wheel recess, respectively.

Advantageously, the laterally outer ends of the reinforcing element are drawn downwards so as to shield the fuel tank laterally, thereby providing protection even in the event of a low-level collision.

Conveniently, the reinforcing element may be formed of a plurality of individual sections each having a U-shaped cross-section. The number of sections may in this case be varied to achieve the desired behaviour during deformation.

Since the spare wheel recess is normally situated in the central area of the floor plate and a silencer of the exhaust system must be arranged on one side of the motor vehicle adjacent the longitudinal girder, a greater volume of the fuel tank may be disposed substantially only on one side, and only on this side is it necessary to provide a reinforcing element.

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a partial plan view of a lateral area of the tail floor arrangement of a motor vehicle with the reinforcing element shown emphasized; Figure2 is a section along the line ll-ll in Figure 1, and Figure 3 is a section along the line Ill-Ill in Figure 1.

Figure 1 shows a spare wheel recess 2 formed in a floor plate 1, only part of the area of the recess being shown. Lateral, box-section, longitudinal girders 3, of which only one is illustrated in broken lines, extend below the floor plate 1, being joined to the latter by spot welding. In the region of the rear axle and at the rear end of the vehicle the two longitudinal girders are joined to one another by cross members 4 and 5.

A fuel tank 6, disposed below the floor plate 1 and below the longitudinal girder 3, is indicated by thick dash-dot lines. In a compact motor vehicle with a short rear overhang a fuel tank 6 of adequate capacity must extend laterally from below the spare wheel recess 2 beyond the longitudinal girder 3.

As may be seen from Figure 1, the fuel tank 6 is situated at a distance from the rear cross member 5 which is dimensioned such that in the event of a rear collision below a prescribed velocity the rear area of the longitudinal girder 3 and the floor plate 1 or of the spare wheel recess 2 respectively are deformed in an energy-dissipating manner and the fuel tank 6 is not damaged.

In a conventional tail floor arrangement in which the floor plate 1 extends laterally beyond the longitudinal girder 3 and is joined to a lateral wall 7, the fuel tank 6 extending laterally beyond the longitudinal girder 3 would not be adequately protected in the event of a collision from the side.

To provide such protection, a reinforcing element element 8 extending laterally outwards from the longitudinal girder 3, overlapping the fuel tank 6 and emphasized by thicker lines, is disposed below the floor plate 1.

The reinforcing element 8 is provided with an undulating or corrugated cross-section in a longitudinal section through the vehicle (see Figure 3) and is joined to the laterally projecting part of the rear cross member 5.

The reinforcing element may, alternatively, be formed by a plurality of individual sections having a U-shaped cross-section, so that the desired reinforcing behaviour may be achieved by varying the number of such sections.

If the motor vehicle has a floor plate 1 which is situated sufficiently low, the design of the reinforcing element 8 indicated in thick lines will suffice, but if the floor plate 1 is relatively high and the fuel tank 6 is disposed behind - when viewed from the sidea bumper 9 of plastics material for example carried round the corner of the vehicle, the reinforcing element 8 may be drawn downwards so as to shield the fuel tank 6 laterally, as indicated by dash-dot lines in Figure 2.

By virtue of the arrangement and design of the reinforcing element 8, in the event of lateral collision a relatively deformation-free bracing of the forces is absorbed on the longitudinal girder 3 and by way of its connection to the cross members 4 and 5, whereas in the event of a rear collision the desired deformation for absorbing energy will not be prevented but rather improved.

Claims

1. Afloorarrangementforthetail of a motor vehicle in which longitudinal box girders at the back of the vehicle are interconnected by a cross member overlying the rear axle and a rear cross member and a recess for the spare wheel is formed between the box girders and between the cross members, a fuel tank being disposed partly below the spare wheel recess and partly laterally of the latter; wherein a reinforcing element disposed below or above the floor plate extends laterally outwards from the longitudinal girder and overlaps the fuel tank.

2. A floor arrangement according to Claim 1, wherein the reinforcement elements has an undulating cross-section when viewed in a longitudinal section through the vehicle.

3. Afloor arrangement according to claims 1 and 2, wherein the laterally outer ends of the reinforcing element are drawn downwards so as to shield the fuel tank laterally.

4. A floor arrangement according to any preceding claim, wherein the reinforcing element is formed of a plurality of individual sections each having a U-shaped cross-section.

5. A floor arrangement for the tail of a motor vehicle, constructed substantially as herein described with reference to and as illustrated in the accompanying drawings.