CPC F16K 31/426 (2013.01) [B64C 13/504 (2018.01); F16K 11/0712 (2013.01)] | 8 Claims |
1. A switching valve comprising:
a sleeve having a plurality of ports;
a spool inside the sleeve and configured to move in an axial direction by a pilot hydraulic pressure to switch between switching lines, each switching line serving as a flow channel for hydraulic fluid and formed by a combination of the ports;
a first energizing unit configured to energize the spool against the pilot hydraulic pressure;
a relief hole on the spool to discharge the hydraulic fluid with the pilot hydraulic pressure;
a valve body configured to close the relief hole; and
a second energizing unit configured to energize the valve body toward the relief hole of the spool against the pilot hydraulic pressure to close the relief valve, and to allow the relief valve to open when the pilot hydraulic pressure exceeds a predetermined value.
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