Patent attributes
A press-working method comprises: cutting out a member with a predetermined shape from a sheet material, the member having a longitudinal direction; bending the member with the predetermined shape to form a bottom portion and a wall portion extending at an angle from the bottom portion as seen in a direction along the longitudinal direction such that the bottom portion has an arched surface as seen in a side view, using at least one plunger and at least one die, wherein an edge of the wall portion is allowed to expand along the plunger and the die while changes in a thickness of the wall portion is controlled by the plunger and the die, and wherein the step of cutting out a member is performed such that the wall portion has an edge with a preset shape after the bending step.