FRONT PART OF THE BODY OF A VEHICLE, COMPRISING SIDE REINFORCEMENTS IN CASE OF A FRONTAL IMPACT WITH ANOTHER VEHICLE

Front part of the body of a vehicle, comprising side reinforcements in case of a frontal impact with another vehicle. Each of the ends of the front beam (1) comprises a rigid reinforcing end piece (4) secured to, and extending from, the front beam (1) and being curved towards the rear of the vehicle, the reinforcing end piece (4) being covered with a damping cover (6).

BACKGROUND

This invention relates to a front part of the body of a motor vehicle.

Automakers are concerned about reducing the cost of repairing vehicles in the event of an “urban” impact, that is, at a slow speed.

The behavior of motor vehicles in this impact situation is regulated and tested through a new European frontal impact protocol called “frontal impact compatibility”.

A known front part of the body of a motor vehicle comprises a transverse metal front beam whose two opposite ends are each connected to the front end of a shock absorber the rear end of which is connected to the front of one of the two side sills of the vehicle body.

FIG. 1partially shows in perspective one side of the body of a vehicle according to the prior art and comprising the transverse front bumper beam1, one of whose two ends is connected to the front end of the shock absorber2whose rear end is connected to the front of the corresponding side sill3of the body C of the vehicle.

FIG. 2is a top view of the frontal impact test of the above-mentioned new protocol according to which the vehicle V is projected at low speed against a deformable barrier B onboard a mobile carriage CM representative of a second vehicle whose front side is represented by the deformable barrier B.

Success in this test depends on not “assaulting” the barrier B, that is to say not to tear or pierce the barrier B during the frontal impact of the vehicle V with the deformable barrier B offset from the axis of movement of the vehicle V.

As shown inFIG. 1, the ends of the front beam1each end substantially at a right angle to the corresponding shock absorber2, and the ends comprise sharp edges1awhich may tear the barrier B during the frontal impact test ofFIG. 2.

To satisfy the new frontal impact protocol, a new front bumper beam of the front part of a motor vehicle with sufficiently stiff overhangs on the sides of the front beam is known as is the reinforcement of the front beam to limit its protection to the center. However, this known solution results in a heavier front beam and a larger section in order for the beam to be sufficiently stiff on the sides. In addition, this known solution does not completely solve the problem of tearing of the barrier B and, consequently, of the bumper skin of the vehicle represented by the movable carriage CM and the barrier B because the stiffness of a front beam is not always easy to adjust on the sides.

U.S. Pat. No. 9,073,496 discloses a front bumper beam structure of a motor vehicle, with reinforcements inserted into the front cross-beam and made of transverse steel tubes extending fully along this cross-beam.

However, such a known front bumper beam structure of a vehicle does not at all address the problem of tearing a deformable barrier during the frontal impact test with a vehicle according to the new frontal impact protocol previously mentioned.

SUMMARY

This vehicle front part aims to overcome the above disadvantages of the prior art.

This purpose is achieved by virtue of a front part of the body of a vehicle, in particular an automobile, comprising a transverse front bumper beam the two opposite ends of which are each connected to the front end of a shock absorber, the rear end of which is connected to the front of one of the two side sills of the body, wherein each of the ends of the front beam comprises a rigid reinforcing tip integral with the front beam as an extension thereof and which has a curvature directed towards the rear of the vehicle and in that the reinforcing tip is clad in a damping shell.

Advantageously, the reinforcing tip is fastened in a corresponding end portion of the front beam by welding or gluing.

Alternatively, the reinforcing tip is fastened in the corresponding end portion of the front beam by a foam expanded in this end portion.

Advantageously, the damping shell is fastened by gluing around the reinforcing tip and, where appropriate, by gluing at its connection to the end of the front beam.

Preferably, the reinforcing tip comprises two parallel and superimposed metallic tubes of circular or rectangular sections respectively housed in two internal compartments of the end part of the front beam.

Advantageously, the damping shell is a profile made of a composite material.

The rear of each shock absorber has a plate which is itself fastened to a plate, which in turn is fastened to the front of the corresponding side sill. A gusset is fastened between the two plates and a box made of a composite material is fastened at right angles between the gusset and the end of the front beam.

DETAILED DESCRIPTION

FIGS. 3 to 6show portions of a front portion of the body C of a motor vehicle comprising a metal front bumper beam1extending transversely from the vehicle. One end of the front bumper beam is connected to the front end of a shock absorber2, the rear end of which is connected to the front of one of the two side sills3of the body C.

Although not shown, the opposite end of the front beam1is connected to the front end of the other shock absorber, the rear end of which is connected to the front of the other of the two side sills3of the box C.

The two shock absorbers2are located in the extension respectively of the two side sills3.

In addition, the two shock absorbers2and the two side sills3of the body C are arranged symmetrically to the median vertical plane of the motor vehicle.

The front portion of body C further comprises a rigid reinforcement tip4integral to each end of the front beam1as an extension thereof and which has a curvature directed towards the rear of the vehicle so as to cover the side of the front beam1.

The rear end of each shock absorber2has a plate2awhich is fastened to a plate3awhich itself is fastened to the front end of the corresponding side sill3. The fastening of the two plates2aand3ato each other can be accomplished using bolts, not shown.

Preferably, the reinforcing tip4is made up of two parallel metallic tubes5, for example made of steel, which are superimposed, each being bent towards the rear of the vehicle, projecting beyond the vertical plane containing the shock absorber2and the corresponding side sill3.

The two curved tubes5are housed by their end parts respectively in two internal elongated compartments1bformed in the hollow part of the front beam1and are fixed in these two compartments by suitable means.

For example, the two reinforcing tubes5can be fastened by welding in the compartments1bof the front beam1by laser or welding beads or can be fastened by gluing with a structural adhesive or a mastic, especially in the case where the front beam1would have a square cross section. Such a fastening method must be provided in the case where the front beam1is made up of a new part (redesigned) so that the reinforcing tubes5at each end of the front beam1will be assembled during the production of the beam itself.

In the case where a pre-existing front beam1is reused (i.e., retrofitted with the reinforcing tubes5), the reinforcing tubes5are inserted into the corresponding end portions of the front beam1at the end of assembly of the vehicle and these tubes can be maintained in the end parts of the front beam1by injecting a suitable dose of expanding foam into each compartment1bof the beam, which foam, once expanded, will solidify the reinforcing tubes5in the corresponding hollow end parts of the front beam1.

FIGS. 3 to 5show that each of the reinforcing tubes5has a circular cross section, but they may have a rectangular or square cross section that will allow them to adjust themselves in their respective internal compartments of matching shape1bof the front beam1, being of course integrated into the end parts of this beam by the aforementioned fastening means.

It is nevertheless preferable to make the two reinforcing tubes5of circular section which do not have a sharp edge that can be “aggressive” vis-à-vis the barrier B, which represents another vehicle, as shown inFIG. 1.

For the purpose of damping upon contact of either side of the front beam1with the barrier B, a damping shell6is provided which is preferably made up of a profile of composite material, as is apparent fromFIGS. 6 to 8.

The damping shell6has a hollow body comprising two parallel internal compartments6ain which are respectively housed the two reinforcing tubes5of the corresponding end of the front beam1. Thus, each damping shell6matches the curved shape of the two corresponding reinforcing tubes5and can be fastened around the reinforcing tubes5, for example by injecting an expanding foam into each compartment6aof the damping shell6to secure the two tubes in their respective compartments6aonce the foam has expanded.

Preferably, the composite material of the damping shell6is of the short fiber type, making this material inexpensive.

Where appropriate, the damping shell6may be fastened, for example by gluing, at its connection portion to the front beam1as shown inFIG. 6.

FIGS. 9 to 11show an alternative embodiment that applies in the context of a gusset7front side sill3which is fastened between the two plates2a,3arespectively of each shock absorber2and the side sill3by means of fastening bolts8.

Such a gusset7is mainly present in the case of a motor vehicle that has no lower track, but only an upper track comprising the two front side sills3.

According to this embodiment, in addition to the presence of the reinforcing tip4with tubes5and the damping shell6at each end of the upper front beam1, a box9, preferably of composite material, is provided with internal partitions for reasons of inertia and lightening and which is mounted at a right angle between the metal gusset7and the upper front beam1.

As best shown inFIG. 11, box9comprises a corner-forming top portion9athat can be fastened by gluing under the lower flange of the upper front beam1and that is connected to an edge9bsubstantially perpendicular to the corner9aand adapted to abut against the beam1that is behind it during assembly before fastening the upper corner9aunder the flange of the beam1.

Box9further comprises a bottom wall9cwhich is fastened, for example by gluing, on the lower hanging part of the gusset7of the side sill3. Alternatively, the bottom wall9ccan be fastened to the gusset7by self-tapping screws10, only one of which is shown inFIG. 11.

Thus, even in the case of a motor vehicle with neither a lower track nor a lower beam, the addition of the box9between each gusset7and the high beam1makes it possible to increase the contact area with the deformable barrier B, as well as the stability of the beam1, which is reinforced.

The vehicle front part described above has the following advantages:

it does not necessarily require the use of a new beam of the front part of the vehicle body and, therefore, does not involve additional investment, reducing manufacturing costs,

the high beam assembly, reinforcing tips with curved tubes and damping shells have a smaller mass than that of a reinforced beam of the prior art, about 0.5 kg less,

it fully meets the new European frontal impact protocol “frontal impact compatibility” due to the fact that each reinforcement tip does not present a risk of assaulting that would likely tear the deformable barrier B representing another vehicle and that the damping shell not only dampens and softens the contact of each end of the beam with the deformable barrier B, but also cancels any sharp edge of the metal parts to avoid tearing the deformable barrier,

it offers an improvement in front overhang of about 10 mm, which results in more freedom for the structures of front styles of motor vehicles;

the reinforcing tip of each end of the high front beam can be offered in various versions, that is to say it can be mounted or not, to each of the ends of this beam, depending on the geographical area of use of motor vehicles, which impose or not requirements that must comply with the new frontal impact protocol.