| 摘要 |
PROBLEM TO BE SOLVED: To prevent cutting of the needle valve part of a motor-driven flow rate control valve into a valve seat. SOLUTION: A motor driven flow rate control valve comprises a valve body 1 wherein a screw hole part 2a is formed and provided with a valve seat 6, and a fluid inflow hole 8 and a central hole 2 communicating with a fluid outflow hole 3 are formed with the valve seat situated therebetween, a drive pin 4 inserted in the central hole of the valve body and forming a male screw 4a threadedly engaged with a screw hole part, and provided at its tip with a needle valve part 5 opposed to a valve seat; a rotor body 14 formed integrally with the driven pin, a magnet 13 for a stepping motor rotatable around the same axis as that of the rotor body, a case 17 for closing surrounding the rotor body and the magnet and forming a closed space the stator and an electromagnet coil part 30 of the stepping motor situated on the outer periphery side of the closed case, and an elastic operation clutch A or B situated between the rotor body and the magnet and having low limit transmission torque in a valve closing rotation direction to prevent cutting of a needle valve part into the valve seat.
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