1. Field of the Invention
The present invention relates to an impact absorbing unit for a vehicle, and more particularly to an impact absorbing unit for a vehicle having a columnar piece of wood and a metallic housing covering the lateral faces of the wood. This impact absorbing unit is typically subjected to an axial compressive force due to the impact in the event of a traffic collision.
2. Description of the Related Art
For example, Japanese Laid-open Patent Application Publication No. 2001-182769 discloses art relating to the impact absorbing unit mentioned above. The impact absorbing unit is subjected to a compressive force that is caused by an impact. According to the publication, a piece of wood fitted in an aluminum hollow square tube with a small gap can reduce fluctuation of the compressive force (or the resistive force during the deformation) to provide improved impact-energy absorption capacity. Furthermore, matching the direction of the wood grain to the axis of the housing can provide an increase in the amount of impact energy absorbed.