Patent ID: 6925713
Filing Date: 2005-08-09
Classification: B21H,Y10T

Abstract:
1. A method of manufacturing an annular member from a disc-shaped metal sheet material defining an outer periphery, comprising the steps of: forming the disc-shaped metal sheet to have a non-processed portion including the outer periphery and a stepped portion defined by an inclined wall, and an inner swelling portion connected to the outer periphery by the stepped portion, the outer periphery and the swelling portion lying in different planes; rotating the disc-shaped metal material; pressing the outer periphery of the metal sheet material in a radially inward direction, while continuing to rotate the metal sheet material; thickening the outer periphery axially and without buckling by said pressing; protruding the outer periphery to either side of the non-processed portion of the metal sheet material; and forming a peripheral wall protruding to either side of the non-processed portion.