| 摘要 |
PURPOSE:To obtain a compact motor-driven valve device easy to be attached to a valve already provided by making use of a planetary gear speed reducer and an impact starting device. CONSTITUTION:When an electric motor 100 is turned in the direction of closing valve body 400, a valve stem 402 is lowered, and when the valve body reaches a closing final end, torque reaction force is produced, thus allowing the second sun gear 209 to begin to turn against the damping force of a brake 250. Hereby, a limit switch 230 sliding on and making contact with an eccentric cam 217 fixed on the gear 209 is operated, allowing the power source of the motor to be cut off. Then, when the electric motor 100 is turned in the direction of opening valve body 100, an impact starting device 300 is operated, allowing opening torque to be transmitted to the valve steve 402. In this case, although the larger torque than the damping force of the brake 250 is generated instantaneously, the second sun gear 209 is not turned because of the action of a damper 240. Namely, in case of opening start, larger torque than closing and tightening torque is transmitted. |
