Patent ID: 6484547
Filing Date: 2002-11-26
Classification: B21D,B21H

Abstract:
A method of manufacturing a sheet metal member, which is made from a thin disc-shaped blank defining a center, wherein an annular projection is integrally formed with at least one surface of a circular base plate from the thin disc-shaped blank so as to be concentric with each other, comprising the steps of:holding and rotating the thin disc-shaped blank between upper and lower dies, at the same time while pressing a groove on an outer peripheral surface of a thickening-forming roller, against an outer peripheral portion of the blank which extrudes outwardly from the upper and lower dies, thereby forming a thickened outer peripheral portion of the blank; holding and rotating the blank with the thickened outer peripheral portion between another upper and lower dies, at the same time while pressing an edge angle portion of an outer peripheral surface of a drawing roller against one surface of the thickened outer peripheral portion which extrudes outwardly from the upper die of the blank, and rotating the drawing roller, and drawing the thickened outer peripheral portion while moving the drawing roller in the direction of the center of the blank, thereby bulging the annular projection axially.