| 摘要 |
PURPOSE:To work a defect-free product without undue stress with one time of rotary forging by upsetting a blank material to a sufficiently large diameter with respect to the diameter of a punch then upsetting the hollow hole part with the punch which is advanced thereafter. CONSTITUTION:A shaft-like blank material W is supplied to the top end face 36 of an inner sleeve N in the hole of a bottom die 32. A die L is moved upward to support the blank material with a knockout punch N, the inner sleeve, the punch 47 of a punch indentor U and a top die 41. When the pressing force for working is applied continuously to the material W, the material is strongly pressed to the punch 46 of the indentor U which rotates inclinedly at an angle theta. A pressing force in an arrow M direction is loaded on a die 32 and a pressing force in an arrow S direction is loaded on the punch N to move upward the entire part of the die L. The material W is upset and is forcibly expanded easily toward the outside circumference in a die cavity 33. The die 41 starts retreating relatively with the punch 46 and when the punch N is moved downward and the die 32 is moved further upward, the hollow formed article provided with a flange by the pressing shoulder surface 43 of the indentor U is completed. |
