| 摘要 |
PURPOSE:To improve the proportional relationship of a proportional solenoid valve between current and flow rate, by making the area of the downstream side of a valve element greater than the area of the upstream side of the valve element. CONSTITUTION:A valve element 18 is disposed facing a valve seat surface 16 in a valve body 10 formed therein with a flow-in passage 12 and a flow-out passage 14. The valve element 18 is secured to a plunger 20, and is pressed against the valve seat surface 16 by means of a spring 24. The plunger 20 is secured thereto with a movable core 26 adapted to be driven by an electromagnetic coil 32 and a diaphragm 28 forming a cancel pressure chamber 32 communicated with the flow-in passage 14. The opening area of the valve is determined by the degree of current fed to the electromagnetic coil 32. Since the area of the valve element 18 on the side facing the flow-out passage 14 is greater than that on the side facing the flow-in passage 12, the force of fluid which depresses the valve element 18 becomes greater in such a phase that the opening degree is less. Therefore, an increase in flow rate, caused by a large pressure differential is canceled out, thereby it is possible to maintain the relationship between current and flow rate.
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