| 摘要 |
PROBLEM TO BE SOLVED: To obtain a structure which prevents the occurrence of damage at a mandrel and an outside-diameter constriction mold, and can improve the accuracy of a shape of a ring-shaped member after processing.SOLUTION: A mandrel 23a is constituted of a pair of support shaft parts 38a, 38b, and a rolling shaft part 39 which is arranged between both the support shaft parts 38a, 38b with respect to an axial direction. Then, an outside-diameter constriction mold 37 for constricting an external peripheral face of a metal raw material in processing is arranged. Furthermore, a pair of movable annular members 36a, 36b are arranged at a portion opposing an internal peripheral face of the metal raw material. Both the movable annular members 36a, 36b are supported by elastic support means 52 in a state that the members can be displaced to a radial direction when prescribed pressing forces are applied thereto. Then, when the prescribed pressing forces in the radial direction are applied to both the movable annular members 36a, 36b from the metal raw material during the processing, both the movable annular members 36a, 36b are displaced to directions of the pressing forces, and thereby the internal stress of the metal raw material in a molding space is decreased.SELECTED DRAWING: Figure 2 |
