| 摘要 |
PURPOSE:To enable easy forming of desired thread grooves for a pipe material made of various materials, by press-contacting a rolling roll advanced at a desired pitch by rotation of a guide shaft while the pipe material is in rotation on the outer peripheral face of the pipe material. CONSTITUTION:A pipe material 1 is held by a chuck A. A motor 2 is rotated by a timer, and at the same time, a driving device B is operated to advance the pipe material 1 in the direction of C together with the device A. The device A is stopped at the final position of advance where a mandrel 24 fits in the hollow part of the pipe material 1. At the same time, rolling rolls 36 are press-contacted on the outer periphery of the pipe material 1. By this press contact, the force of rotation of the pipe material 1 is transmitted to the mandrel 24 and guide shaft 2. By rotation of the shaft 27, a supporting cylinder 26 screwed to this is advanced according to the pitch of the thread grooves 28. In succession to this process, three rolls 36 advance while press-contacted to the pipe material 1 and form thread grooves of desired pitch on the outer periphery of the pipe material 1. |
