| 摘要 |
PURPOSE:To form exactly a rack tooth form by press work, by providing a relief on the side of a rack shaft slug and making it absorb a flow of an excess thickness generated in case of the press work. CONSTITUTION:A groove 8 is provided as a relief for absorbing a flow of an excess thickness along the longitudinal direction of a shape, on both sides, respectively, of a rack shaft slug 1'. The rack shaft slug 1' is interposed between a press die 2 which matches exactly a final shape of a rack tooth and a press upper die 3 which matches the back of the rack, and is pressed as indicated with an arrow I. A flow of an excess thickness by press work is absorbed by the groove 8. In this way, even if depth of the upper die 3 is deepened, its wedging force is small, therefore, it is not feared that the press upper die 3 is not broken down, and also the back shape of the rack is not broken down due to a flow of an excess thickness. |
