| 摘要 |
PROBLEM TO BE SOLVED: To obtain a desired thrust or braking force of a hydraulic actuator while suppressing the pressure acting on a pressure chamber on the drive side or the control side of the hydraulic actuator to the minimum pressure.SOLUTION: A constant pressure control hydraulic driving device of the present invention includes transformers 7 and 8 for controlling a pressure and a flow rate of pressurized liquid supplied to cylinders 10 and 11. The transformer 7 and 8 are constituted by mechanically connecting input and output axes together of three variable displacement hydraulic pumps/motors 7a, 7b, 7c and 8a, 8b, 8c, respectively. One of the variable displacement hydraulic pumps/motors 7b and 8b is connected to a constant pressure source 1 via a high-pressure pipe line 13 and a low-pressure pipe line 14; The other of the variable displacement hydraulic pumps/motors 7b and 8b is connected to the cylinder 10 and 11 via a first conduit line 15 and 16 respectively while being connected to the constant pressure source 1 via the low-pressure pipe line 14; and the other of the variable displacement hydraulic pumps/motors 7c and 8c is connected to the cylinder 10 and 11 via a second conduit line 18 and 19 respectively while being connected to the constant pressure source 1 via the low-pressure pipe line 14. |
