摘要 |
A seat valve body mounted in a hydraulic line between a pump line and feeder lines to control hydraulic fluid supplied to variable throttles and to auxiliarily control hydraulic fluid flowing in a load line comprises a first seat valve having a variable control throttle displaced by a difference between a load pressure of the load line and a discharge pressure of the hydraulic pump and varying an opening area from the pump line to the feeder lines based on a displacement amount thereof, a second seat valve having a pilot variable control throttle displacing with respect to the first seat valve, determining a displacement amount of the first seat valve, and varying an opening area based on a displacement amount thereof; and a pilot spool having a pilot variable throttle determining a displacement amount of the pilot variable control throttle of the second seat valve upon switching.
|