Padding for the seat proper of a vehicle seat and a seat proper equipped with such padding

Abstract

Padding for the seat proper of a seat, the padding comprising a visco-elastic foam and a comfort foam. The visco-elastic foam extends between a bottom face of the seat proper and an intermediate level of the padding. The comfort foam extends between the intermediate level and the top face of the seat proper. The comfort foam and the visco-elastic foam extend both over the rear and over the front of the seat proper.

1 . Padding for the seat proper of a vehicle seat, the padding extending in a longitudinal direction between a rear portion serving to receive the pelvis of an occupant sitting on the seat and a front portion, and in a vertical direction, between a bottom surface designed to face towards a vehicle floor, and a top surface designed to face towards the body of the occupant, said padding comprising at least: 
 a comfort foam that is soft both when the seat proper is in normal use, and when the vehicle decelerates suddenly; and    a visco-elastic foam that is stiffer when the vehicle decelerates suddenly than when the vehicle is in normal use;    said visco-elastic foam extending from the bottom surface, and said comfort foam, secured to said visco-elastic foam, extending to the top surface of the padding;    said comfort foam and said visco-elastic foam extending from the rear portion to the front portion of the padding, wherein said visco-elastic foam presents a stiffening thickness that varies.    
   
   
       2 . Padding according to  claim 1 , in which said rear portion presents a rear end, and said front portion presents a front end; 
 in which said comfort foam presents a comfort thickness that varies between said rear end and said front end; and    in which a ratio between the comfort thickness and the sum of the comfort thickness and of the stiffening thickness varies in said longitudinal direction.    
   
   
       3 . Padding according to  claim 2 , in which said ratio decreases from said rear end to said front end.  
   
   
       4 . Padding according to  claim 2 , in which said rear portion extends from said rear end towards the front end over a distance corresponding substantially to one third of the distance between the front end and the rear end, and in which, in the rear portion, said ratio lies in the range 40% to 80%, and preferably in the range 50% to 70%.  
   
   
       5 . Padding according to  claim 2 , in which said front portion extends from said front end towards the rear end over a distance corresponding substantially to one third of the distance between the front end and the rear end; and 
 in which, in the front portion, said comfort foam presents a comfort thickness smaller than 0.05 m, and preferably smaller than 0.03 m.    
   
   
       6 . Padding according to  claim 1 , in which said visco-elastic foam presents a stiffening coefficient R greater than 10, the stiffening coefficient R being defined as the ratio between dynamic lift and quasi-static lift, lift being the ratio between the compression force to be exerted on the surface of a portion of foam in order to deform said portion by 50% and the area of said surface of the portion, dynamic lift being obtained for a deformation rate of not less than 10 s −1 .  
   
   
       7 . Padding according to  claim 1 , further comprising an intermediate portion between said front portion and said rear portion, and a rigid element which is mounted on the bottom surface of said intermediate portion.  
   
   
       8 . A seat proper having a rigid structure on which padding according to  claim 1  is mounted, said padding being covered with a cover.  
   
   
       9 . A seat proper structure having a rigid structure on which padding according to  claim 1  is mounted, said padding further comprising an intermediate portion between said front portion and said rear portion, and said rigid structure further comprising a rigid element disposed facing said intermediate portion of said padding.