HYDRAULIC OPERATING VALVE FOR EXCAVATOR

摘要

An excavator oil pressure control valve is provided to reduce the functioning noise of actuator and to lengthen the lifetime of excavator since the stream passage cross section is changed according to the pressure gradient of the inlet port and inside flow path. A pilot valve(130) of excavator oil pressure control valve comprises a valve body(131) in which a receiving part(133) is formed in the central part and an external aperture(135) is formed in the sidewall part, a piston(150) is installed in order to move along the receiving part of the valve body, a check valve(160) which blocks a variable through-hole(153) of piston if the pressure of the inlet port(112) rises, and a spring(143) which elastically supports the piston to the inlet side.