| 摘要 |
An energy regeneration system does not affect operation of a hydraulic actuator except when a relief valve is operating, improves energy recovery efficiency by connecting an actuator hydraulic line to a regeneration hydraulic motor with a small pressure loss during regeneration, and ensures holding pressure of the hydraulic actuator when the energy cannot be regenerated, thereby preventing unintended operation. A first valve device (51) is disposed between actuator hydraulic lines (101a, 101b) and a regeneration hydraulic motor (61). The first valve device (51) has a throttle passage (51a) capable of increasing the pressure in the higher pressure side actuator hydraulic line to a set pressure of the relief valves (48a, 48b). A second valve device (52) is disposed in parallel with the first valve device (51) between the actuator hydraulic lines and the regeneration hydraulic motor 61. The second valve device (52) is switched from a close position (E) to an open position (F) by the pressure between the first valve device (51) and the regeneration hydraulic motor (61) when the pressure between the first valve device (51) and the regeneration hydraulic motor (61) increases to approach the set pressure of the swing relief valve. |
