Energy-absorbing buffer for motor vehicle bumper incorporates devices for low and high collision speeds, that for low collision speeds being plastically deformable

摘要

The low and high collision speed energy-absorber for a motor vehicle bumper is a plastically deformable tube running in the vehicle longitudinal direction. The deformation tube (5), at least over a part of its length, is connected coaxially with a tension casing (10) made of a shape memory material. The tension casing, on heating, undergoes a diameter alteration with effect from a defined value, which causes an increased friction between it and the deformation tube. The tension casing is connected to the deformation tube with a friction value such that, with a relative movement between them on the basis of a collision speed greater than 50 km/per hour, a heating of the tension casing due to diameter alteration occurs because of the friction.