The technology disclosed in this specification relates to an impact energy absorber which absorbs a compression load input to a tubular main body in the tube axis direction and which is suitable for a crush can of a vehicle, and the like, and to a fabrication method of the impact energy absorber.
As conventionally known in the art, a vehicle is provided with a crush can as an impact energy absorber at, for example, the front end of the front side frame or the rear end of the rear side frame for absorbing impact energy (impact compression load) produced by a head-on or nose-to-tail collision of vehicles.
For impact energy absorbers, such as aforementioned crush cans, and the like, various improvements have been proposed to increase the impact energy absorbability. For example, the pamphlet of WO 2006/025559 describes that a tubular main body of an impact absorber is composed of at least one first portion having a short tubular shape and at least one second portion having a short tubular shape concentrically stacked on the first portion, wherein an engagement portion of the first portion and the second portion is inclined with respect to the concentric axis. When a compression load is input to the main body in the tube axis direction, the diameter of the first portion decreases while the diameter of the second portion increases so that the first portion is pushed into the inner hollow of the second portion. This structure serves to suppress occurrence of unstable buckling phenomenon so that deformation mode is stabilized, thereby improving the impact energy absorbability.