| 摘要 |
<p>A pressure control valve automatically controllable of a set value of a pressure circuit by pilot operation without using an electrical signal, is provided. A pressure control valve include a valve body (30) opposing to a seat surface of a relief port (A) connected to a pressure circuit (46) and a spring (32) biasing the valve body (30) onto the seat surface, for flowing out a part of the fluid within the pressure circuit (46) to hold the fluid pressure in the pressure circuit (46) at a predetermined set pressure when the fluid pressure in the pressure circuit (46) is higher than or equal to the set pressure. Apilot piston (40) is arranged movably in expansion and contraction direction of the spring (32) at an end portion of the spring (32) remote from the valve body (30), the pilot piston (40) moves in a direction for compressing the spring (32) when a predetermined pressure of a pilot fluid is input. A spring force of the spring (32) is increased and decreased by varying compression force of the spring (32) by moving the pilot piston (40) depending upon increasing and decreasing of the pressure of the pilot fluid. <IMAGE></p> |
