| 摘要 |
A pilot check valve comprises: a valve body which forms a flow path for connecting a first main port and a second main port and has a valve seat formed on the flow path; and a closing part for closing/opening the flow path as the closing part is in contact with/separated from the valve seat. The closing part includes a head and a stem. The head is in contact with the valve seat to close the flow path and is separated from the valve seat in the first direction to open the flow path. The stem is formed to extend from the head along a second direction opposite to the first direction. The closing part has a cross-sectional area reduction interval in which the cross-sectional area decreases along the second direction from a contact point with the valve seat. In the cross-sectional area reduction interval, the cross-sectional area decrease rate is less than or equal to zero along the second direction over the entire interval and is less than zero along the second direction at the end interval. The cross-sectional area reduction interval includes at least one cross-sectional area reduction delay interval The at least one cross-sectional area reduction delay interval has a greater rate of change in the cross-sectional area along the second direction than in an area adjacent to the first direction. Poppets, plungers, etc. can be manufactured in a structure and shape capable of meter-out control of flow rate to enable smooth operation, thereby suppressing the occurrence of shock and vibration. |
