| 摘要 |
<p>A main valve mechanism for opening and closing a main flow path between a first port and a second port has a main valve body, a large-diameter first piston for opening the main valve body, a main pressure operating chamber for driving the first piston, and first spring means for closing the first piston. An auxiliary valve mechanism for opening and closing an auxiliary flow path has an auxiliary valve body, a small-diameter second piston for opening the auxiliary valve body, an auxiliary pressure operating chamber for driving the second piston, and second spring means for closing the second piston. The main pressure operating chamber and the auxiliary pressure operating chamber are connected to each other through a connecting hole. The relationships between the diameters of both the pistons and the spring forces of both the spring means are such that the second piston is actuated by lower fluid pressure than the first piston. <IMAGE></p> |
