| 摘要 |
A preform including first and second outer members (10, 20) having peripheral borders overlapped and jointed for forming outer surfaces (61, 62) of a hollow section of a hydroformed product (60), and a reinforcement member disposed between the first and second outer members for forming a partition wall (65) that substantially divides the hollow section. The outer members have sidewalls (61A, 62A) inclined relative to an overlapping surface (OS) of the first and second outer members, and summit parts (61B, 62B) surrounded by the sidewalls. The reinforcement member has one and the other ends (31, 41) jointed to areas which are to form the summit parts of the first and second outer members, and lateral edges (35,45) which face peripheral areas (15A, 25A) of the first and second outer members which are to form the sidewalls. |
