Impact absorption unit has foam having density of 0.2 to 0.5 grams per cubic centimeter and compression rate of 60 percent or more, and which is arranged in each hollow portion of metallic housing

摘要

A foam (2) is arranged in the hollow portions (12-14) inside a metallic housing (1). The foam has a density of 0.2 to 0.5 grams per cubic centimeter and a compression rate of 60 percent or more.