| 摘要 |
<p>Disclosed is a motorized needle valve in which a first port (11) which communicates with one end of a communication hole (31) and a second port (12) which communicates with the other end of said communication hole (31) are formed in a port block (10) serving as a housing (24), and a needle valve shaft (18) provided with a tapered part (18a) is mounted inside the communication hole (31) in such a way as to be mobile in the axial direction. The needle valve shaft (18) is driven in the axial direction by means of a screw shaft (27) which is driven in rotation by an electric motor (20), and the rotation of the needle valve shaft (18) is restricted by means of a bar (42) which serves as a guide. The needle valve shaft (18) is provided with a pressure-counteracting shaft (36) which has a pressure-receiving piston (38), and axial thrust applied to the needle valve shaft (18) in the direction of the screw shaft (27) by fluid in the second port (12) is counteracted by means of the pressure-receiving piston (38).</p> |
