ARM-VARIABLE REGENERATIVE VALVE FOR HEAVY EQUIPMENT FOR PREVENTING HUNTING GENERATED IN 'ARM-IN' SINGLE DRIVING OR 'ARM-IN AND SWING' COMPOSITE DRIVING

摘要

PURPOSE: An arm-variable regenerative valve for heavy equipment is provided to expand the durable life span of parts and to improve response property by preventing hunting generated in the "arm-in" single driving operation or the "arm-in and swing" composite driving operation by variably controlling and regenerating actuating fluid drained from a hydraulic cylinder. CONSTITUTION: An arm-variable regenerative valve for heavy equipment is composed of a hydraulic cylinder connected to a hydraulic pump to drive an arm; a control valve for the arm installed to a passage between the hydraulic pump and the hydraulic cylinder to control the flow direction of actuating fluid; a swing control valve(40) installed at the passage between the hydraulic pump and the control valve and composed of a piston(8), a spool(6), and a swing piston(3); an oil leakage preventing unit formed at one end of the spool closely contacted to the piston to prevent the oil from leaking from a hydraulic cylinder port(P2) to a back pressure chamber(16) of the other end of the spool; and a damping orifice(19) formed in the rear side of the swing piston to protect the swing piston, the spool, and the piston moving in rising the pressure in the hydraulic cylinder port from shock. The piston moves by the operating pressure of the hydraulic pump. The spool is switched by the piston to control the actuating fluid discharged from the hydraulic cylinder. The swing piston moves in supplying a pilot signal pressure to switch the spool.