| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for forming a fiber flow within a product in parallel with a product's contour even to the inner part while suppressing flaws caused in a processing portion of a bearing outer ring material and deformation thereof in heat treatment.SOLUTION: In the method for producing a bearing outer ring material, an annular ring-like material 1 formed by cutting a steel pipe is attached to an annular die 2 for cold forging parallel, and an upper punch 3 and a lower punch 4 are disposed above and below the ring-like material 1 to iron the ring-like material 1 by these punches. The ring-like material 1 attached between the upper punch 3 including a base portion 3a having a diameter larger than the inside diameter of the ring-like material 1 and smaller than the outside diameter thereof, a tapered portion 3b on the tip side, and a circular base portion 3d at the tip and the lower punch 4 including a base portion 4a, a tapered portion 4b on the tip side and a circular base portion 4d at the tip, which are vertically symmetrically shaped, is cold ironed by the upper punch 3 and the lower punch 4, whereby the fiber flow along the inside diameter surface of the bearing outer ring material is formed inside uniformly and parallel. |
