| 摘要 |
<p>PURPOSE:To perform a fine control of the title hydraulic actuator easily, by releasing a confluence of pressure oil automatically when a load pressure of an oil pressure actuator driven by confluent pressure oil delivered from plural pumps is lower than a prescribed value. CONSTITUTION:A switch valve 15 which can always close an oil passage staying between the oil chamber I of a logic valve 18 and a tank 19 by a spring and open it when a pressure signal acts in a pilot chamber, is provided. And a changeover valve 24 which can always connect a pipe going to the pilot oil chamber of the switch valve 15 to a tank circuit by the spring and to a pilot pipe coming from the outside when pressure oil larger than a set value acting in the pilot oil chamber is provided. And also the pipes of pressure oil flowing into pressure oil changeover valves A, B are formed by branching and led to the pilot oil chamber of the changeover valve 24. By this constitution, fine control is easily performed.</p> |
