Abstract:
A motor vehicle door including an outer panel and an inner shell panel that are interconnected at the lower ends thereof by a door sill plate that extends transversely in relation to the two panels. The door sill plate is reinforced with a reinforcing element that is fixed to the plate and that extends along most of the length and width thereof.

Description:
BACKGROUND 
     The present invention relates to a vehicle door reinforced against side impacts. 
     It is known that motor vehicle doors generally comprise an outer panel and an inner box-section panel which are interconnected at their lower portion by a door bottom wall extending transversely with respect to the two panels. 
     These doors offer relatively low resistance to side impacts. 
     To overcome this drawback, motor vehicle doors are often reinforced by reinforcing bars which extend behind the outer panel of the door and are situated virtually halfway up the door. 
     However, these reinforcing bars are insufficient to prevent the door from opening toward the inside of the vehicle during a side impact at a speed below 60 km/h. 
     This opening of the door toward the inside of the vehicle is harmful to the passengers. 
     This opening is due to the fact that the lower portion of the door situated below the aforementioned reinforcing bars has inadequate strength. Specifically, this inadequate strength allows said portion to deform by passing above the rebate of the vehicle sill box-section. Since the lower portion of the door is no longer retained by this rebate, the door can open inwardly, seriously injuring, or even killing, the passengers. 
     BRIEF SUMMARY 
     The object of the present invention is to overcome this drawback by reinforcing the lower portion of motor vehicle doors. 
     According to the invention, the motor vehicle door comprising an outer panel and an inner box-section panel which are interconnected at their lower portion by a door bottom wall extending transversely with respect to the two panels, is characterized in that said door bottom wall is reinforced by a reinforcing element fastened to this wall and extending along a major portion of the length and the width of this wall. 
     According to one version of the invention, said reinforcing element consists of at least one metal plate having a greater thickness than said door bottom wall. 
     In a first embodiment of the invention, said reinforcing element is a metal plate of which one of the longitudinal edges is fastened against the internal face of the inner box-section panel and of which the other longitudinal edge is fastened against the internal face of the door bottom wall, close to the outer panel. 
     Preferably, said plate forms an acute angle with the inner box-section panel and with the door bottom wall and has, on each of its longitudinal edges, an edge strip which is folded parallel to the wall to which it is fastened. 
     Tests have shown that this plate prevented the door from opening inwardly in the event of side impacts occurring at average speeds. 
     In a second embodiment of the invention, said reinforcing element comprises at least one bar fastened against the external face of the door bottom wall. 
     According to other specific features of this second embodiment:
         said bar is fastened in a recess stamped in said door bottom wall, such that the outer face of said bar is situated substantially in the continuation of that part of the door bottom wall situated outside said recess;   one of the longitudinal edges of the bar is situated substantially in the continuation of the internal box-section wall so as to be situated opposite the rebate formed in the vehicle sill box-section when the door is closed.       

     Preferably, said longitudinal edge has a cross section in the form of a point which is designed to be able to penetrate into the adjacent rebate of the sill in the event of a side impact on the door. 
     This arrangement affords increased protection in the event of a side impact by even further reducing the risks of the door opening toward the inside of the vehicle. 
     In an even more preferred embodiment of the invention, the bottom of the door is reinforced both by at least one plate of the above-described type and by at least one bar as described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other particular features and advantages of the invention will become more apparent from the description which follows. 
       In the appended drawings which are given by way of nonlimiting examples: 
         FIG. 1  is a perspective view of a motor vehicle door whose outer panel has been removed, showing an element for reinforcing the door bottom wall, 
         FIG. 2  is a view in cross section through a motor vehicle door comprising the reinforcing element and through the vehicle sill box-section, 
         FIG. 3  is a similar view to  FIG. 2 , showing the deformation of the door under the effect of a side impact, 
         FIG. 4  is a view in cross section through a door and through the vehicle sill box-section, the door bottom wall being reinforced by a bar, 
         FIG. 5  is a view of the internal face of a door and of the door bottom wall reinforced by two bars. 
     
    
    
     DETAILED DESCRIPTION 
     In the embodiment represented in  FIGS. 1 and 2 , the motor vehicle door comprises an outer panel  1  (removed in  FIG. 1 ) and an inner box-section panel  2  which are interconnected at their lower portion by a door bottom wall  3  extending transversely with respect to the two panels  1 ,  2 . According to the invention, said door bottom wall  3  is reinforced by a reinforcing element  4  fastened to this wall  3  and extending along a major portion of the length and the width of this wall  3 , covering the central region thereof. 
     In this example, this reinforcing element  4  consists of a metal, for example steel or aluminum, plate which preferably has a greater thickness than the door bottom wall  3 . 
     As is shown by  FIGS. 1 and 2 , particularly  FIG. 2 , the reinforcing element  4  is a metal plate of which one  4   a  of the longitudinal edges is fastened, preferably by welding, against the internal face of the inner box-section panel  2  and of which the other longitudinal edge  4   b  is fastened in the same way against the internal face of the door bottom wall  3 , close to the outer panel  1 . 
     In the example represented in  FIG. 2 , the plate  4  forms an acute angle with the inner box-section panel  2  and with the door bottom wall  3  and has, on each of its longitudinal edges, an edge strip which is folded parallel to the wall  2  or  3  to which it is fastened. The plate  4  thus forms a bracket which reinforces the lower portion of the door. 
       FIG. 3  shows the deformation experienced as a result of a side impact applied by a barrier  5  moving at a speed of around 60 km/h. 
     This barrier  5  moves above the vehicle sill box-section and in particular above the rebate  7  which is opposite the lower portion  2   a  of the box-section wall  2  of the door. 
     It can be seen from  FIG. 3  that the door and the sill box-section  6  are folded toward the inside of the vehicle but the lower portion  2   a  of the box-section wall  2  of the door remains pressed against the rebate  7 . The door has not opened. 
     This result can be explained by the presence of the reinforcing plate  4 , which significantly increases the resistance of the lower portion of the door to the deformation occurring in the event of a side impact. 
     In the embodiment represented in  FIGS. 4 and 5 , the reinforcing element comprises two metal bars  8  which are fastened, by means of screws  9 , against the external face of the door bottom wall  3 . 
     In this example, the bars  8  are fastened in a recess  10  stamped in the door bottom wall  3 , such that the outer face  8   a  of the bars  8  is situated substantially in the continuation of that part  3   a  of the door bottom wall  3  situated outside the recess  10 . 
     Moreover, one  8   b  of the longitudinal edges of the bars  8  is situated substantially in the continuation of the lower portion  2   a  of the internal box-section wall  2  so as to be situated opposite the lower portion of the rebate  7  formed in the vehicle sill box-section  6  when the door is closed. 
     Furthermore, the longitudinal edge  8   b  of the bars  8  has a cross section in the form of a point  8   c  which is designed to be able to penetrate into the adjacent rebate  7  of the sill  6  in the event of a side impact on the door. 
     In the example represented in  FIG. 4 , the lower portion of the door comprises not only the reinforcing bars  8  but also the reinforcing plate  4  described with reference to  FIGS. 1 to 3 . 
     The simultaneous presence of the reinforcing plate  4  and of the bars  8  provides the lower portion of the door with an increased resistance to side impacts. 
     In the event of a side impact, the pointed ridge  8   c  of the bars  8  becomes embedded in the rebate, thereby even further preventing the risk of the door opening toward the inside of the vehicle. 
     The double reinforcement above is particularly suited to two-door vehicles each having a relatively long length, that is to say a length which is sensitive to side impacts, as in the case of coupés.