| 摘要 |
PURPOSE:To reduce the torque loss of a valve driving device as well as make the device small in its size by fitting the torque of said device to a torque curve required for practically turning a valve plate, etc. CONSTITUTION:The end part of a valve shaft 4 reaches the inside of a fluid cylinder mechanism 10, and on said end part an arm 5 positioned inside the cylinder is mounted. Through a plate-shaped member 33 between piston members 31, 32 a long hole 34 is bored, and in this long hole 34 a pin 51 provided on the arm 5 is slidably inserted. The torque applied to a valve shaft 4 changes according to a cosine curve that reaches the maximum value thereof when the arm 5 is fitted to a straight line (C), and the minimum value thereof (zero) when it is in parallel to the cylinder axis. By avoiding use of the torque zero point of this cosine curve, it is possible to fit the torque of the valve driving device to a desired torque characteristic. |
