Energy absorption unit for a rear bumper of an automobile

The assembly (10) has a plastic beam (12) with a crosspiece (14) extended in a transverse direction (Y) between lateral absorption elements (16) i.e. crash-boxes. Each element has dimension larger than that of the crosspiece in a longitudinal direction (X) perpendicular to the former direction such that the beam has U-shape. Metallic reinforcement elements have lateral support plates (22) against which corresponding absorption elements are supported. A central reinforcement part (24) is supported against the crosspiece. A connection arm (26) is extended between one of the plates and the part. An independent claim is also included for a motor vehicle comprising a chassis.