| 摘要 |
<p>Provided is a needle valve in which a gap between a valve casing and a needle is reliably sealed and an origin of the needle can be readily obtained with high precision. A needle (6) is screwed into a cylindrical rotor (44) of a stepping motor (7) so as to be retractable, and a rotation regulating member (47) prevents the needle (6) from rotating together with the rotor (44). Accordingly, in a case of driving the motor (7) to rotate the rotor (44), the needle (6) vertically moves without rotating. A lower limit sensor (61) and an upper limit sensor (60) detects a detection target piece (49) provided to the rotation regulating member (47), so a lower limit position and an upper limit position of the needle (6) are obtained. The motor (7) is controlled such that, after the motor (7) is driven until the lower limit sensor (61) detects the detection target piece (49), an origin sensor (71) monitors an origin detection plate (62) so as to stop at a predetermined rotation stop position. Thus, an origin of the needle (6) is obtained.</p> |
