HYDRAULIC DRIVE SYSTEM OF CONSTRUCTION MACHINE

摘要

This hydraulic drive system of a construction machine includes: a first hydraulic pump and second hydraulic pump that can, independently of each other, adjust a tilt angle; a turning control valve for controlling the supply of hydraulic fluid to a turning motor; and a boom primary control valve and boom secondary control valve that are for controlling the supply of hydraulic fluid to a boom cylinder. The turning control valve and the boom secondary control valve are disposed on a first bleed line, and the boom primary control valve is disposed on a second bleed line. Pilot pressure is output from a turning operation valve to the turning control valve, and pilot pressure is output from a boom operation valve to the boom primary control valve. When a turning operation and a boom raising operation are performed simultaneously, a boom lateral regulation valve does not output pilot pressure to the boom secondary control valve.