| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic closed circuit system in which, even while a portion to be driven can be driven by a hydraulic fluid, fine position control can be performed on the portion to be driven.SOLUTION: A hydraulic closed circuit system 100 capable of driving a hydraulic cylinder 3 includes: a hydraulic pump 1; an electric motor 2 for controlling the rotation of the hydraulic pump 1; a shuttle valve 7 in which a secondary side port 7c communicates with a first conduit C1 and a secondary side port 7c communicates with a second conduit C2; a charge pump 5 in which an ejection port communicates with a primary side port 7a of the shuttle valve 7; a relief valve 8 which makes a charge pressure by the charge pump 5 a set pressure; and a check valve 20 which is disposed in a third conduit C11 communicating the primary side port 7a and a hydraulic fluid tank T1 and prohibits outflow of a hydraulic fluid from the primary side port 7a to the hydraulic fluid tank T1. The charge pump 5 sets the first conduit C1 and the second conduit C2 to the charge pressure through the shuttle valve 7. |
