HYDRAULIC SERVO DRIVE DEVICE AND VALVE DEVICE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic servo drive device capable of surely detecting abnormality of a driven body such that a poppet valve is not returned from an opening side, and also to provide a valve device using the same. SOLUTION: This EGR valve device 1 includes: a hydraulic servo drive device 4 having a pilot spool 22 sliding by a pilot pressure and a servo piston 16 sliding to follow the pilot spool 22 by a pump pressure; a poppet valve 3 driven by the hydraulic drive device 4; a stroke sensor 29 alternatively detecting a position of the servo piston 16 or the pilot spool 22 as a lift position of the poppet valve 3; a proportional control valve 31 supplying the pilot pressure; and a controller for controlling the proportional control valve 31 based on detection signals from the stroke sensor 29. COPYRIGHT: (C)2009,JPO&INPIT