Impact absorption structure of vehicle seat

Abstract

Impact absorption structure is provided in side frame element of seat cushion frame, wherein the side frame element has a vertical planar portion, an upper flange portion and a lower flange portion. A centroidal line is utilized as important factor, which extends along a vertical section of those vertical planar portion and upper and lower flange portions. Namely, an upper portion of the centroidal line is inclined by a certain angle toward a side inwardly of the seat cushion frame, and a module of section of said lower flange portion is smaller than a module of section of said upper flange portion, thereby allowing the side frame element to be deformed by impact load toward a side outwardly of the seat cushion frame and thus absorbing the impact load. For example, an inward extension may be merely formed in the upper flange portion to realize such impact absorption structure.

1 . An impact absorption structure of vehicle seat, comprising; 
 a seat cushion frame including a side frame means;    the side frame means having a vertical planar portion and a peripheral flange element formed in peripheral ends of the vertical planar potion, wherein the vertical planar portion includes an upper end facing to a side upwardly of the vehicle seat and a lower end facing to a side downwardly of said vehicle seat, and said peripheral flange element includes: an upper flange portion formed in said upper end of said vertical planar portion; and a lower flange portion formed in said lower end of said vertical planar portion; 
 and  
   a means for making said side frame means prone to deformation by an impact imparted to said seat cushion frame, said means including a centroidal line which extends vertically along a whole vertical section of said side frame means which includes a vertical section of said upper and lower flange portions, said centroidal line having an upper portion facing to the side upwardly of said vehicle seat,    wherein said means is arranged in said whole vertical section of said side frame means as well as in said vertical section of said upper and lower flange portions, such that said upper portion of said centroidal line is inclined by a predetermined angle in a direction to a side inwardly of said seat cushion frame, and that a module of section of said lower flange portion is smaller than a module of section of said upper flange portion, thereby allowing said side frame means to be deformed by said impact toward a side outwardly of said seat cushion frame, and thus absorbing the impact.    
   
   
       2 . The impact absorption structure of vehicle seat as claimed in  claim 1 , wherein said vertical planar portion of said side frame means extends along a plumb line, and wherein said means comprises an inward extension which is formed in said upper flange portion so as to extend therefrom to the side inwardly of said seat cushion frame, whereby said upper portion of said centroidal line is inclined by said predetermined angle in a direction to the side inwardly of said seat cushion frame, while said module of section of said lower flange portion is smaller than said module of section of said upper flange portion.  
   
   
       3 . The impact absorption structure of vehicle seat as claimed in  claim 1 , wherein said means is arranged in a predetermined local area of said side frame means.  
   
   
       4 . The impact absorption structure of vehicle seat according to  claim 2 , wherein said inward extension is formed in and along said upper flange portion at a limited length, so as to allow a local area of said side frame means to be deformed by said impact in a direction to the side outwardly of said seat cushion frame.  
   
   
       5 . The impact absorption structure of vehicle seat according to  claim 4 , wherein there is provided a connection means for connecting said side frame means with a seat adjustment means provided under said vehicle seat, and wherein said inward extension is disposed adjacent to said connection means, so that said local area of said side frame means is defined near to said connection means, thereby decreasing a degree of deformation of said local area.