Rear floor for an automobile and automobile including such a floor

A rear floor for an automobile, including a series of ribs punched into the metal sheet of the floor and extending in the longitudinal direction of the vehicle. At least one of the punched-in ribs is connected to an adjacent rib by a rib portion that is inclined relative to the longitudinal direction.

The present invention relates to a rear floor for a motor vehicle.

The rear floor is that part of the floor that extends under the luggage storage space.

This rear floor is made up of at least one metal sheet having pressed ribs running in the longitudinal direction of the vehicle to increase the bending and torsional strength of the rear floor.

The axis of the rear wheels is situated under the rear floor.

As the vehicle drives along, the wheels and the exhaust line transmit to the rear floor vibration waves that generate noise perceptible in the passenger compartment of the vehicle despite the sound-proofing lining covering the floor and the elastic mounts used to connect the wheel suspension components to the floor.

The longitudinal ribs of the floor make it possible to some extent to attenuate the vibrations but do not attenuate them sufficiently to meet the comfort criteria demanded by users.

It is an object of the present invention to address this disadvantage by creating a rear floor capable of effectively attenuating vibration waves transmitted to it as the vehicle is driving along.

This object is achieved, according to the invention, using a rear floor for a motor vehicle comprising a series of ribs pressed into the sheet metal of the floor, running in the longitudinal direction of the vehicle, characterized in that at least one of the pressed ribs is connected to an adjacent rib by a rib part that is inclined with respect to the longitudinal direction.

Tests carried out by the applicant company have indeed surprisingly demonstrated that by connecting at least one of the ribs to an adjacent rib via an inclined rib part, the vibrations transmitted by the rear floor as the vehicle is driving along are significantly attenuated.

This results in an appreciable reduction in the noise in the passenger compartment and in an increase in the level of comfort felt by the occupants.

Advantageously, said rib, said inclined rib part and said adjacent rib together form a Y.

In a preferred version of the invention, said inclined rib part and said adjacent rib are situated in a region near the rear edge of the rear floor, the opening of the two branches of the Y facing toward the rear edge of the floor.

In this version, said adjacent rib is situated in the continuation of another rib running parallel to said rib.

In another preferred version of the invention, said inclined rib part is connected to said rib in a region near the rear edge of the rear floor, the opening of the two branches of the Y facing toward the front edge of the floor.

According to other specifics of the invention:said rib extends near a lateral edge of said rear floor;said rib, said inclined rib part and said adjacent rib are situated in a region near the middle of the rear floor;said ribs are uniformly spaced;the distance between the ribs is more or less equal to the width of the ribs.

The invention also relates to a motor vehicle equipped with a rear floor according to the invention.

Other particulars and advantages of the invention will become even more apparent throughout the following description.

The rear floors depicted inFIGS. 1 and 2comprise two lateral edges1,2, a front edge3and a rear edge4.

The front edge3is intended to be connected to a floor running under the passenger compartment of the vehicle and notably supporting seats for the occupants.

The lateral edges1,2adopt the shape of the rear wheel arches.

Each of the rear floors comprises a series of pressed ribs5,6,7,8,9,10,11,12;5a,6a,7a,8a,9a,10a,11a,12awhich run in the longitudinal direction X of the vehicle.

These ribs5,6,7,8,9,10,11,12;5a,6a,7a,8a,9a,10a,11a,12agive the rear floor good bending strength.

The rear floors depicted inFIGS. 1 and 2are intended to be positioned just above the axis of the rear wheels and are therefore affected by the vibration waves generated as the vehicle drives along.

Thus, these rear floors usually transmit to the passenger compartment noise that can be perceived by the occupants as troublesome.

The rear floors have been selected following comparative testing for their ability to absorb the vibrations generated when a vehicle equipped with such floors is driving along.

These comparative tests were carried out on a test bed using sensors that measure the transmission of vibration waves in the longitudinal direction X, the transverse direction Y and the vertical direction Z of the vehicle.

These measurements made it possible to devise diagrams comprising, on the ordinate axis, the amplitude and on the abscissa axis, the frequency of the vibrations.

The frequency range was between 20 and 300 Hz.

The best results were obtained for the rear floor depicted inFIG. 1.

The amplitude-frequency diagram obtained revealed an aptitude to absorb frequencies at around 250 Hz.

Excellent results were also obtained in the case of the rear floor depicted inFIG. 2which offers an advantage for frequencies close to180Hz.

In the two rear floors, one12(seeFIG. 1) or8a(seeFIG. 2) of the pressed ribs is connected to an adjacent rib13or9avia a rib part14or14awhich is inclined with respect to the longitudinal direction X.

In the case of the rear floor depicted inFIG. 1, the rib12, the inclined rib part14and the rib13together form a Y when the floor is studied from front to rear, viewed from above. This Y thus has a more or less straight long branch formed by the rib12and a short branch formed by the adjacent rib13and the inclined rib part14, the adjacent rib13being more or less parallel to the rib12.

Moreover, the rib13adjacent to the rib12and forming the short branch of the Y is situated in the continuation of a rib11parallel to the rib12.

The rib11is thus shorter than the rib12and is separated from the inclined rib part14by a space15.

FIG. 1also shows that the rib12that forms a Y with the short rib13is a rib which runs close to the lateral edge2of the rear floor.

In addition, the inclined rib part14and the short rib13are situated in a region close to the rear edge4of the rear floor. The opening of the two branches of the Y thus faces toward the rear edge4of the vehicle.

In the case of the rear floor depicted inFIG. 2, the two ribs8a,9aare connected to one another by a rib part14athat is inclined with respect to the axis X.

This inclined rib part14ais situated in a region close to the rear edge of the rear floor. The ribs8aand9aare thus connected on the side of their end, the common branch of the Y formed by the end of the rib8abeing very short by comparison with the previous embodiment, the two branches of the Y that are formed by the ribs8aand9aby contrast being very long. In this embodiment, the opening of the Y therefore faces toward the front edge3of the floor.

Moreover, the rib8a, the adjacent rib9aand the inclined rib part14aare situated in a region near the middle of the rear floor.

FIGS. 1 and 2also show that all the ribs5to12or5ato12aare uniformly spaced and that the distance between the ribs is more or less equal to the width of the ribs.

The number of ribs5to12or5ato12ais equal to8, but can vary between6and10notably according to the width of the vehicle intended to be equipped with such a rear floor.

The advantages obtained with rear floors according to the invention can essentially be explained by the rib parts14,14athat connect two adjacent ribs.

Given that these rib parts14,14aare inclined with respect to the longitudinal axis X of the vehicle, their presence in the rear floor has no impact on the bending or torsional strength of the floor.

Of course, the invention is not restricted to the two examples that have just been described and numerous modifications can be made to these without departing from the scope of the invention.

Thus, the rear floor could comprise more than two ribs joined together by inclined rib parts such as the parts14and14a.

Further, these two ribs that are joined together by inclined parts could be situated in regions other than those depicted inFIGS. 1 and 2.

It is also possible to combine the embodiments depicted inFIGS. 1 and 2.