PURPOSE: To drawing form a cup-shaped body possessed of a rugged pattern in one stage by using a die possessed of a rugged periphery surface on its cavity and a punch surrounded its rigid core with an elastic cylindrical member of larger outside diameter than the minimum diameter of the die and by drawing forming.
CONSTITUTION: The punch 11 is provided with the rigid core 13 of steel, etc. and the cylindrical part 14 made of the elastic material such as urethane rubber, etc. surrounding a side wall 13a of the core 13. And the outer diameter of the cylindrical part 14 is larger than the outer diameter of a flange part 13b, moreover, larger than the minimum diameter (d) of the shoulder curvature part 19 of the die 12. Furthermore, the clearance 15 is formed between the cylindrical part 14 and the side wall 13a of the core except the upper part 14a, the whole body of the punch 11 is able to get into the cavity 12b of the die 12. Then, on the peripheral wall surface 16 of the cavity of the die 12, the rugged part 18 is formed by plural stepped parts 17 of ring shape. And then, when the punch 11 is pushed into the cavity 12b of the die 12, a blank 10 is drawn and its body wall part 2 is elastically pressed on the peripheral wall surface of the cavity to form the rugged pattern 4.
HIROTA KAZUSANE
AKAMATSU KATSUSHI
| JPS574408A | 1982-01-11 | |||
| JPS5145005U | 1976-04-02 | |||
| JPS58117919U | 1983-08-11 |