| 摘要 |
PROBLEM TO BE SOLVED: To reduce a load applied to a die of punch, etc., so as to extend a die life and to forge a height dimension of inner boss part in the cylindrical part having center boss part in high precision when manufacturing a cylindrical part with cold forging. SOLUTION: The outer peripheral part of a product stock 50 is squeezed at the beginning and a columnar center boss part 16 and discoid cylinder stock part 64 are formed, successively, the outer peripheral side part of cylinder stock part 64 is bent and an annular part 74 is subjected to ironing to produce an objective cylinder part 12. |
