| 摘要 |
<p>PURPOSE: A flow control device of an actuator for a construction heavy equipment is provided to keep uniform flow from a hydraulic pump to the actuator even though the signal pressure, applied to operate a seat valve, is over the predetermined pressure. CONSTITUTION: A flow control device of an actuator for a construction heavy equipment comprises a first seat valve(501) which is movably installed on a housing installed to a seat valve body(500) and has a pilot pressure control variation throttle varying by the flow rate; a second seat valve(502) which is openably installed between a pump passage(5) of the hydraulic pump and moving passages(7A,7B,7C), and has a control variation throttle varying the opening space between the pump passage and the moving passage when moving on the first seat valve; a third seat valve(503) which is elastically installed to move to the second seat valve and controls an operation oil, discharged from the hydraulic pump, to flow in one direction; and an auxiliary piston(604) which is slidably installed in a pilot spool(41), switches the pilot spool by being fed back by the operation oil from a low side passage, and expands the crossing passage by moving the second seat valve when the pressure of the lower side passage is over the predetermined value.</p> |
