| 摘要 |
<p>PURPOSE:To make pressure raisable only in case of being necessitated, by forming both low-pressure side and high-pressure side interconnecting ports in a peripheral part of a cylinder and, when a plunger exists an end of the high-pressure side, making the high pressure side interconnecting port so as to be closed. CONSTITUTION:A low-pressure side interconnecting port 4c and a high-pressure side interconnected port 4b both are formed in each position where both come into a state of being opened when a plunger 3 on a peripheral part of a cylinder 4 exists in an end of the low-pressure side but when this plunger 3 exists in an end of the high-pressure side, the high-pressure side alone comes into a state of being opened. And, the low-pressure side interconnecting port 4c is connected to each of check valves 9 and 12. With this constitution, when the low-pressure side interconnecting port 4c is closed, high pressure oil is discharged out of the high-pressure side port 4b, and when the low-pressure side interconnecting port 4c is opened, steady-state pressure is discharged, so that only in case of being necessitated, fluid pressure is raisable.</p> |
