Negative-angle press-working die

A negative angle press forming die, comprising:

• a bottom die;
• a rotational support mechanism incorporated into the bottom die;
• a fixed support base;
• a swing die, having a negative angle female press-forming part and a support die, supported by the rotational support mechanism and inclined at an inclination determined according to a height range of a curved shape to be formed;
• a top die;
• a pressing die, movably connected to the top die, to cooperate with the support die and the fixed support base to hold a workpiece therebetween;
• and
• a slide cam, moveable according to the vertical movement of the pressing die, having a negative angle male press forming die part to engage the negative angle female die part of the swing die to press form the workpiece,
• wherein the swing die is divided into swing die segments arranged in a line according to the height range of the curved surface to be formed, and cams for turning the swing die segments such that adjacent swing die segments are turned sequentially at time intervals, and
• wherein said cams include drive cams attached to the top die and taper cams attached to respective back surfaces of the swing die segments.