| 摘要 |
PROBLEM TO BE SOLVED: To provide a control device with an auxiliary oil control valve in a block of a direction changing valve for controlling the amount of oil to be supplied to a hydraulic cylinder, having a reduced number of parts and offering compact construction allowing the use in a smaller space. SOLUTION: A seat valve element provided in an oil passage between a pump path and a feeder path for controlling the amount of oil to be supplied to a variable throttle and auxiliarily controlling the amount of oil flowing into a load path comprises a first seat valve having a control variable throttle to be displaced with a difference between the loading pressure of the load path and pressure on the discharge side of a hydraulic pump for changing an opening area ranging from the pump path to the feeder path with the displacement, a second seat valve having a pilot control variable throttle to be displaced with respective to the first seat valve for determining the displacement of the first seat valve and changing the opening area with the displacement, and a pilot spool having a pilot variable throttle for determining the displacement of the pilot control variable throttle of the second seat valve during change-over. COPYRIGHT: (C)2003,JPO
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