METHOD OF MANUFACTURING DISK MEMBER

摘要

A method of manufacturing a disk member, wherein a cylindrical boss part (1B) is formed by axially compressing a burring part (Wb) by a cope (5) and a drag (6) from both upper and lower directions for elastic deformation. Since an annular recessed part (6A) is formed in the pressing face of the drag (6), the burring part (Wb) in the course of elastic deformation is hard to escape in the radial outer direction. Thus, the base part (lower part) of the burring part (Wb) can be filled in the annular recessed part (6A) without any clearance to form the cylindrical boss part (1B) without leaving underfill at the axial end part thereof.