| 摘要 |
<p>A single piece valve box for a rotary slide valve has on its inner circonference axial control grooves (3) of which the axial length is delimited by the surface of the inner circonference. Said valve box is produced by forming from a flank, for example a pipe section. In a first step, the control grooves (3) are shaped by cold forming so that one of their ends (4) is closed and the other end (5) is open. The open ends of the control grooves (3) are terminated in a partial bore (6) having a larger diameter. A collar (8) having a larger outer diameter is formed on the contour of the valve box at the partial bore (6). In a second step, said collar (8) is pressed inwardly by cold forming till the inner diameter corresponds in that region also to the inner diameter of the remainder of the valve box, thereby closing the other end of the control grooves (3).</p> |
