| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a bell-shaped hollow metallic sphere having high impact absorbing capacity, its manufacturing method and a structural material for absorbing impact. Ž<P>SOLUTION: The bell-shaped hollow metallic sphere 1 is a sphere obtained by bending a metal sheet to form into a spherical partition, wherein an opening part 1b is formed in the partition. The bell-shaped sphere is formed by performing in order: a deep drawing step I where the metal sheet is cut out into an ellipse, a blank wherein the dimension of the major axis and the dimension of the minor axis are different, is used to be subjected to deep drawing, so that both edge parts in the direction of the minor axis are bent and also both end parts in the direction of the major axis are raised; a mouth closing step II where both end parts in the direction of the major axis of the blank obtained by the deep drawing step I are made to approach each other; and a finishing step III where the blank is finished into the sphere while making the edge part of the entire circumference of the blank obtained by the mouth closing step II approach each other. Since the structure having a lot of the bell-shaped hollow balls 1 filled in the hollow structural material is gradually crushed when external force is applied, excellent compressive energy absorbing property is developed. Then, the structural material for absorbing impact is made light in weight. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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