| 摘要 |
<p>PURPOSE:To achieve the reliable drive control of a slide valve by forming an orifice communicating between a pressure receiving chamber and a non- receiving chamber in a main piston for driving the slide valve while leading pressure oil from a high pressure side oil path to be selected in accordance to the movement of the main piston into the pressure receiving chamber. CONSTITUTION:A main piston 23 for driving a slide valve 11 is arranged in a hydraulic cylinder 20 where a pressure receiving chamber 25 and a non- receiving chamber 26 are arranged at the opposite sides. The main piston 23 is coupled with a sub-piston 24 while a sub-cylinder 22 arranged with said sub- piston 24 is formed with plural high pressure side hydraulic paths 51-54 to be selected in accordance to the movement of the sub-piston 24 and to feed pressure oil to the pressure receiving chamber 25. Since an orifice, the pressure receiving chamber 25 and the non-receiving chamber 26 with each other, is formed in the main piston 23, it can function slowly under load-up while quickly under load down.</p> |
