| 摘要 |
PURPOSE:To make radius of shoulder part of an upset formed body to a designated specific value or less when a metallic bottomed cylindrical semi-forming body is fitted to the outside of a columnar core box and inserted into a columnar outer die, by making the gap from the bottom of the columnar core box to specific coefficient relation for radius of shoulder of circular outer edge of the semi-formed body. CONSTITUTION:The metallic bottomed cylindrical semi-formed body 3 made by pressing a discoid blank is fitted to the outside of the columnar core box 4 closely contacting the body, and inserted into the cylindrical outer die 2 closely contacting the body. In this case, the gap DELTAh between the bottom face of the columnar core box 4 and bottom face in the semi-formed body 3 with respect to the radius R0 of shoulder part of circular outer edge of the semi-formed body 3 is made to relation expressed by the formula I and upset by a punch 1. The radius R of the shoulder part of the circular outer edge of the upset formed body 10 becomes a designated value of less than 2mm.. Mass production is possible compared with conventional cold forging and grinding work. |
