Patent ID: 7861489
Filing Date: 2011-01-04
Classification: B21D,B23K,Y10T

Abstract:
1. A hydroforming method comprising: a) disposing a preform inside forming dies having cavity surfaces that correspond to outer surfaces of a hydroformed product, said preform having edges overlapped and jointed, two outer members for forming the outer surfaces of the hydroformed product, and reinforcement members for forming reinforcement ribs that divide a hollow cross section of the hydroformed product, and comprising a joint formed by, when more than three sheet materials for forming said outer members and said reinforcement members are overlapped together, welding a first sheet material on a surface of said overlapped sheet materials to a second sheet material positioned inside said first sheet material, and a space, which is prepared before the formation of said joint, aligned with said joint and disposed between said second sheet material and a third sheet material located inside said second sheet material during said welding process; b) applying a hydraulic pressure to the inside of said preform to expand and deform said preform; and c) forming the outer surfaces of said hydroformed product and reinforcement ribs that divide the hollow cross section of said hydroformed product using the outer members and the reinforcement members.