| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a nearly cylindrical member on the bottom surface of a cup-shaped member of which a large opening is formed and, furthermore, which is also high in dimensional accuracy. SOLUTION: The method of manufacturing a nearly clutch part 1 in which a large opening 2a is formed on the bottom surface of a cup-shaped member comprises: a first stage where a coil material 10 is formed into a desired size by performing trimming and also a blank material 13 is obtained by forming an opening 12 for working by piercing; a second stage where the blank material is formed into the cup-shaped member by performing drawing in the peripheral part of the blank material at the drawing rate of 70-90% several times; a third stage where ironing is applied to the side wall 3 of the cup-shaped member; and a fourth stage where the opening 2a is formed in the bottom part 2 of the cup-shaped member by piercing. COPYRIGHT: (C)2011,JPO&INPIT |
