| 摘要 |
PURPOSE:To improve the flow of a blank material and to economize the number of stages and man-hour by drawing the blank material which is pressed between a die and a blank holder while energizing the flange part thereof in the direction opposing to the angle of a square cylindrical part to be formed. CONSTITUTION:A blank material is supplied on the top surface of a punch 2 where a blank holder 3 energized by a cushion pin 4 is moved upward. The blank material is placed in the home position with the chamfered part of said blank material held coincident with the stroke direction of a push plate 10 fixed to a piston 9. A die 5 descends to press the blank material between the same and the blank holder 3 and a fluid pressure is supplied to the port 11 of a piston 8. A piston 9 advances and a push plate 10 fixed to the piston rod presses the chamfered part of the blank material. When the die 5 descend further, the die 5, the punch 2 and the holder 3 operate cooperatively to progress square cylindrical drawing and the flange part 14 of the blank material is pressed toward the angle part of the square cylindrical part, whereby the flow of the blank material in the wall part of the square cylinder is improved. |
