| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for caulking and joining a metal sheet with high joining strength by suppressing generation of cracks subject to generate on nearly Y-shaped crossing side wall parts, even in caulking joining by using a triradius punch.SOLUTION: A plurality of metal sheets are laminated and placed on movable blades divided into three and arranged on an outer periphery of a triradius fixed anvil. A triradius columnar punch is locally pushed to the metal sheet from above to plastically deform the upside metal sheet, and the movable blades divided and arranged on the outer periphery of the fixed anvil are individually released to the outer peripheral direction to plastically deform the underside metal sheet so as to mechanically join the upside/underside metal sheets. A movable blade in which a corner R is set to be not less than 0.78 t and not more than a radius of an inscribed circle of a punch head flat part is used as the movable blade. However, the t is thickness obtained by summing all the thicknesses of a plurality of the metal sheets. |
