| 摘要 |
PROBLEM TO BE SOLVED: To provide an actuator having light weight, giving large output, ensuring inexpensiveness and allowing easy assembly and overhaul, and further provide a valve drive device capable of opening and closing a valve at high speed. SOLUTION: A valve drive device 1 supplies liquid to the main cylinder 21 of an actuator, so as to raise the internal pressure of the main cylinder 21 to a level exceeding the internal pressure of a sub-cylinder 22, and cause a piston rod 23 in the actuator to reciprocate. The valve drive device 1 is capable of discharging the liquid contained in the main cylinder 21, so as to release the raised internal pressure of the main cylinder 21. In addition, the piston rod 23 is made to reciprocate under the internal gas pressure of the sub-cylinder 22 raised due to the reciprocating motion of the piston rod 23, and this reciprocating motion is converted to a rotary motion for opening and closing a valve 5. |
