HYDRAULIC DRIVE SYSTEM

摘要

In this hydraulic drive system (1), a hydraulic-oil path (15) forms a closed circuit between a hydraulic pump (10) and a hydraulic cylinder (14). When the hydraulic pump (10) supplies a hydraulic oil to the hydraulic cylinder (14) via a flow control valve (16), a direction control valve (44) allows the hydraulic fluid to flow from the hydraulic pump (10) to the hydraulic cylinder (14) but prohibits the hydraulic fluid from flowing from the hydraulic cylinder (14) to the hydraulic pump (10). When a target flow rate is within a prescribed range, a control device (24) uses the flow control valve (16) to control the flow rate of the hydraulic fluid being supplied to the hydraulic cylinder (14), and when the target flow rate is above the aforementioned prescribed range, the control device (24) uses a pump-flow-rate control unit (25) to control the flow rate of the hydraulic fluid being supplied to the hydraulic cylinder (14).