| 摘要 |
PURPOSE:To form accurately a seal ring groove in a body from a sheet of plate and to improve productivity by forming a cylindrical part by bending the edge of a circular flat plate and forming another side wall of a seal ring groove by bending the tip of the cylindrical part. CONSTITUTION:A circular plate 5 is blanked from a plate, and the edge of the circular plate 5 is bent in the axial direction by a press to form a circular flat part 51 and a cylindrical part 52. Then, the flat plate 51 side of the cylindrical part is folded down on the flat plate part by a die 61, a punch 62 and an inner die 63 to form a side wall 53 of the seal ring groove. At the same time, the diameter of the tip side of the cylindrical part is reduced to form a reduced cylindrical part 55. Then, a notch is formed by a notching punch at a specified position of the outer peripheral wall of the reduced cylindrical part 55, and the tip side of the reduced cylindrical part 55 reduced by setting the notch as a reference is stretched in the radial direction by a press die 64. Thus, the bottom wall 55 and other side wall 56 of the seal ring groove are formed. |
