METHOD OF MANUFACTURING VALVE LIFTER

摘要

PROBLEM TO BE SOLVED: To provide a manufacturing method in which thickness of a roughly formed first semifinished product in a cup shape can be formed by a comparatively small forming pressure without causing large deformation to the entire shape. SOLUTION: A cup-shaped first semifinished product is made that has a disk-like top plate and a cylindrical wall projected from the circumferential edge of the top plate to the axial direction by drawing a blank, with spinning performed on the inner surface of the cylindrical wall from the top plate end to the open end in the axial direction, fluidizing the material of the inner surface of the cylindrical wall from the top plate end to the open end to make the wall thinner, and forming a thick part projecting inward at the open end by using the fluidized material.