| 摘要 |
PROBLEM TO BE SOLVED: To produce cylindrical parts high in perpendicularity and flatness of end face in the axial direction and excellent in the surface roughness of the inner peripheral face of a through hole mainly by forging process. SOLUTION: Projection parts 56, 58 projecting in the axial direction are formed to both end faces by a coining forging process (fig (c)), bottomed holes 90, 92 are formed by an extrusion forging process (fig (d)), in a blanking process (fig (e)), a through hole 12 is formed by blanking a bottom part 112 of the bottomed holes 90, 92 with a blanking punch, in a face finishing process (fig (f)), an inner face of the through hole 12 is subjected to burnishing by pushing in a burnishing tool from the side opposite to the inserting side of the blanking punch in a face finishing process, further, by compressing from the axial direction, tip parts of the projecting parts 56, 58 are subjected to plastic deformation to improve a precision. |
