BURRING WORKING METHOD AND BURRING WORKING IMPLEMENT

摘要

PROBLEM TO BE SOLVED: To provide technology for molding a further uniform thick flange in burring working for forming the flange at a plate-like material to be worked such as a steel plate.;SOLUTION: A burring punch 20 is formed into a tapered cylindrical rod shape having a small diameter part 21 at a tip side, a large diameter part 23 at a base side, and a diameter expansion part 22 smoothly connecting the small diameter part 21 with the large diameter part 23 while continuously expanding a diameter from the outer diameter of the small diameter part 21 to the outer diameter of the large diameter part 23. The working surface of the diameter expansion part 22 is a curved line swollen outward and having a curvature radius of ≥12 mm and ≤18 mm. When forming the flange 92 by pressing the punch 20 into a lower hole 91 formed at the material 9 to be worked, the extension of the material of the circumferential edge of the lower hole 91 in a plate thickness direction is suppressed by increasing a diameter expansion direction component of a force applied to the material 9 to be worked from the punch 20.;COPYRIGHT: (C)2012,JPO&INPIT