| 摘要 |
The present invention realizes a structure with which it is possible to prevent damage to a mandrel and to enhance the precision of the shape of a processed ring-like member. A mandrel (23a) is formed of a pair of support-shaft parts (37a, 37b) that are concentrically provided, being separated in the axial direction thereof, and a rolling-shaft part (38) that is provided between the pair of support-shaft parts so as to be concentric therewith in relation to the axial direction. The first support-shaft part (37a) is provided in a state in which displacement thereof in the axial direction with respect to the rolling-shaft part is restricted. The second support-shaft part (37b) is provided in a state in which, when a pressing force from a metal material (26) is exerted thereon in the direction away from the rolling-shaft part, the second support-shaft part (37b) can be displaced in that direction. |
