| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic device in which little energy loss is caused and a rise in temperature of a hydraulic fluid is suppressed.SOLUTION: The hydraulic device includes: a hydraulic actuator 1 including a first cylinder chamber 11 for forward motion, a second cylinder chamber 12 for backward motion with a projected net area smaller than that of the first cylinder chamber 11, and a piston element 13 for defining the respective cylinder chambers; a constant capacity type main hydraulic pump 21 and a sub hydraulic pump 31 capable of pressure-feeding the hydraulic fluid both in normal and reverse directions; a servo motor 4 for driving to rotate the pumps in normal and reverse directions; a closed hydraulic circuit 2 coupling the first cylinder chamber 11 with the second cylinder chamber 12 via the main hydraulic pump 21; and a semi-closed hydraulic circuit 3 for coupling the first cylinder chamber 11 with an oil tank 6 via the sub hydraulic pump 31 to compensate for a difference in amounts of the hydraulic fluid flowing in the closed hydraulic circuit 2 due to a difference in the projected net areas of the first cylinder chamber 11 and second cylinder chamber 12. |
