| 摘要 |
PROBLEM TO BE SOLVED: To realize a structure which prevents damage from occurring in a mandrel and improves the precision of a shape of a post-processing ring-like member.SOLUTION: A mandrel 23a is configured of a pair of support shanks 37a, 37b provided concentrically with each other in a state of axial separation and a form rolling shank 38 provided concentrically between both the support shanks 37a, 37b in the axial direction. One support shank 37a is provided in a state that an axial displacement to the rolling shank 38 is restricted. When a pressing force is applied from a metallic material 26 in the direction of separating from the rolling shank 38, the other support shank 37b is provided in a state of being displaceable in the direction.SELECTED DRAWING: Figure 1 |
