Impact absorber for vehicle

Abstract

An impact absorber for a vehicle has a tubular shape and is disposed between a side member and a bumper beam of the vehicle, so as to be crushed in an axial direction thereof upon application of a compressive load, for absorbing an impact energy. The impact absorber includes: a tubular main body and attachment plates that are fixedly welded to respective axially opposite end portions of the main body. The main body has a thin plate portion having a plate thickness smaller than 1.4 mm and constituting an axially intermediate portion of the main body, and a pair of thick plate portions having a plate thickness not smaller than 1.4 mm and located on axially opposite sides of the thin plate portion. The thick plate portions are held in contact with the respective attachment plates, and are arc-welded to be fixed to the respective attachment plates.

1 . An impact absorber for a vehicle, disposed between a side member and a bumper beam of the vehicle, so as to be crushed like an accordion in an axial direction thereof upon application of a compressive load thereto, for absorbing an impact energy, the impact absorber comprising:
 (a) a tubular main body; and   (b) a pair of attachment plates that are fixedly welded to respective axially opposite end portions of the main body,   the main body having (a-1) a thin plate portion having a plate thickness smaller than 1.4 mm and constituting an axially intermediate portion of the main body, and (a- 2 ) a pair of thick plate portions having a plate thickness not smaller than 1.4 mm and located on axially opposite sides of the thin plate portion,   the respective thick plate portions coming into contact with the respective attachment plates, and being arc-welded to be fixed to the respective attachment plates,   the thin plate portion being constituted of a think plate member having a plate thickness smaller than 1.4 mm,   and the pair of thick plate portions being constituted of a pair of thick plate members having a plate thickness not smaller than 1.4 mm and joined to respective axially opposite ends of the thin plate member.   
   
   
       2 . An impact absorber for a vehicle according to  claim 1 ,
 wherein the tubular main body is constructed of a pair of semi-cylindrical-shaped half bodies each having a generally U shape in a cross section thereof that is perpendicular to the axial direction,   wherein each of the half bodies has widthwise opposite end portions overlapping with the other of the half bodies,   and wherein each of the half bodies is welded at the widthwise opposite end portions thereof to the other of the half bodies, such that the pair of half bodies are joined to each other.   
   
   
       3 . The impact absorber according to  claim 1 ,
 wherein the main body has a cross sectional shape defined by a flat polygon having at least six sides,   wherein said at least six sides include two long sides that are approximately parallel to a long axis of the flat polygon,   wherein the main body has two side surfaces that are represented by the respective two long sides of the flat polygon defining the cross sectional shape,   and wherein each of the two side surfaces is formed with at least one recessed groove that extends in the axial direction.   
   
   
       4 . The impact absorber according to  claim 3 ,
 wherein the cross sectional shape of the main body is defined by a flat octagon as the flat polygon,   and wherein at least one pair of recessed grooves are formed in each of the two side surfaces of the main body, and are symmetrical with respect to the long axis of the flat octagon.   
   
   
       5 . The impact absorber according to  claim 1 , wherein one of the pair of thick plate portions, which is to be located adjacent to the bumper beam, has a length that is larger than 10 mm and is smaller than 40 mm. 
   
   
       6 . The impact absorber according to  claim 2 , wherein one of the pair of thick plate portions, which is to be located adjacent to the bumper beam, has a length that is larger than 10 mm and is smaller than 40 mm. 
   
   
       7 . The impact absorber according to  claim 3 , wherein one of the pair of thick plate portions, which is to be located adjacent to the bumper beam, has a length that is larger than 10 mm and is smaller than 40 mm. 
   
   
       8 . The impact absorber according to  claim 4 , wherein one of the pair of thick plate portions, which is to be located adjacent to the bumper beam, has a length that is larger than 10 mm and is smaller than 40 mm. 
   
   
       9 . The impact absorber according to  claim 1 , wherein one of the pair of thick plate portions, which is to be located adjacent to the side member, has a length that is not smaller than 5 mm and is smaller than 0.15×L, where “L” represents an entire length of the main body. 
   
   
       10 . The impact absorber according to  claim 2 , wherein one of the pair of thick plate portions, which is to be located adjacent to the side member, has a length that is not smaller than 5 mm and is smaller than 0.15×L, where “L” represents an entire length of the main body. 
   
   
       11 . The impact absorber according to  claim 3 , wherein one of the pair of thick plate portions, which is to be located adjacent to the side member, has a length that is not smaller than 5 mm and is smaller than 0.15×L, where “L” represents an entire length of the main body. 
   
   
       12 . The impact absorber according to  claim 4 , wherein one of the pair of thick plate portions, which is to be located adjacent to the side member, has a length that is not smaller than 5 mm and is smaller than 0.15×L, where “L” represents an entire length of the main body. 
   
   
       13 . The impact absorber according to  claim 5 , wherein one of the pair of thick plate portions, which is to be located adjacent to the side member, has a length that is not smaller than 5 mm and is smaller than 0.15×L, where “L” represents an entire length of the main body. 
   
   
       14 . The impact absorber according to  claim 1 ,
 wherein the main body has axially opposite ends, wherein one of the axially opposite ends, which is to be located adjacent to the side member, is approximately perpendicular to an axis of the main body,   and wherein the other of the axially opposite ends, which is to be located adjacent to a longitudinal end portion of the bumper beam, is inclined with respect to a direction perpendicular to the axis, such that a distance between the axially opposite ends of the main body is reduced as viewed in a direction away from a longitudinal central portion of the bumper beam toward the longitudinal end portion of the bumper beam.