| 摘要 |
PROBLEM TO BE SOLVED: To prevent an unnecessary increase in secondary pressure by controlling terminal pressure on a secondary passage at a constant level without using control of pump speed, in a pressure reducing valve system having a main valve and a pilot valve. SOLUTION: A restriction device 31 is disposed, for example, in a primary passage 4 of the main valve 1. A main pressure chamber 47 for secondary pressure introduction facing a first diaphragm 51 and first and second sub pressure chambers 48 and 49 partitioned by a second diaphragm 52 are formed in the pilot valve 6. The second diaphragm 52 has an area A2 larger than an area A1 of the first diaphragm 51, and the ratio of the areas A1 and A2 is set toΔP×A2/A1=Pe, whereΔP is a differential pressure across the restriction device 31 and Pe is a potential pressure loss between the main valve 1 and a downstream target portion M. The differential pressureΔP is transmitted to a pilot valve element 57 after amplification by the area ratio A2/A1 to amplify the secondary pressure of the main valve 1. COPYRIGHT: (C)2005,JPO&NCIPI
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