| 摘要 |
PROBLEM TO BE SOLVED: To provide an actuator for a valve capable of certainly actuating a backstop function by loading it on rotary valves of a ball valve and a butterfly valve, compact and free to reduce cost of it. SOLUTION: A speed reducing gear mechanism 10 is constituted of an input gear 15 to interlock with a rotational driving source 12 and to rotate, an intermediate gear 14 to be engaged with this input gear 15, an eccentric body 17 to eccentrically rotate interlocked with rotation of the input gear 15, an external tooth gear 18 to oscillate and rotate by receiving eccentric rotation from the eccentric gear 15, a frame body 19 to regulate oscillatory rotation of the external tooth gear 18 and an output shaft 20 free to output an autorotating component of the external tooth gear 18 interlocked with the external tooth gear 18, and this actuator for the valve is devised to hold this valve disc 31 at an intermediate opening position by a positional holding mechanism by an eccentric moment of the speed reducing gear mechanism 10 by connecting the valve disc 31 for the valve free to rotate through this output shaft 20 and the valve stem 30. COPYRIGHT: (C)2004,JPO
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