Patent ID: 9744580
Date: 2017-08-29
CPC Classifications: B21D

Claim:
1. An ironing mold for performing ironing on a folded and drawn formed portion which is formed using a surface treated metal plate as a raw material and which has an inner peripheral wall, an outer peripheral wall and a fold portion linking front ends of the inner peripheral wall and the outer peripheral wall, comprising: a punch; a die which is disposed on the outer periphery of the punch and which forms, with respect to the punch, a pushing hole into which the folded and drawn formed portion is pushed with the fold portion to the front; and a counter pad part which is disposed facing the punch and the die in such a manner that the folded and drawn formed portion is positioned between the punch and the die, and which pushes the folded and drawn formed portion into the pushing hole by relative displacement of the counter pad part with respect to the punch and the die, wherein the die includes a shoulder portion disposed on an outer edge of an inlet of the pushing hole and constituted by a curved surface having a predetermined curvature radius, and an inner peripheral surface which extends from a radius end of the shoulder portion in a pushing direction of the folded and drawn formed portion, and along which a surface of the outer peripheral wall of the folded and drawn formed portion slides in response to the pushing of the folded and drawn formed portion, a skewness Rsk of the surface treated metal plate is less than −0.6 and no less than −1.3, and the curvature radius of the shoulder portion and the clearance between the radius end and the punch are determined such that, when the curvature radius of the shoulder portion is represented by r, the clearance between the radius end and the punch is represented by c