| 摘要 |
PURPOSE:To reduce required electric power, by using two movable valve elements and a rod for moving them, to equalize the liquid pressure on the front of each valve element to that on its rear. CONSTITUTION:A first valve element 12 is provided in a liquid chamber (a) which communicates with an input port 2. A second valve element 11 is provided in a liquid chamber (c) which communicates with a flow return port 5. The end of the second valve element 11 is located in a liquid chamber (b) which communicates with an output port 4. The second valve element 11 receives the force of a holding spring 15. A rod 10, which is operated by an armature 8, acts to both the valve elements 12, 11. When a solenoid 6 is energized, the rod 10 moves the second valve element 11 downward. At that time, the liquid forces acting to the front and rear of the valve element 11 are balanced to each other bacause the diameter of a valve seat 16 is equal to that of a seal 19. When the rod 10 pushes the first valve element 12 after the energizing of the solenoid 6, the liquid pressure on the front of the valve element and that of its rear are equalized to each other by an orifice 13. For that reason, the electric power required for the solenoid 6 is small. |
