| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a hydraulic driving apparatus for working machine, which prevents a pressure drop on a meter-in side and stably lowers a load. <P>SOLUTION: There is provided the hydraulic driving apparatus for the working machine comprising a hydraulic pump 2, an engine 1, a hydraulic actuator 4, a manipulation device 6, a hydraulic circuit for work including a meter-in flow passage and a meter-out flow passage, and a regeneration flow passage 83 in down driving, a direction selector valve 3 changing a working oil supply amount according to the manipulation device 6, a meter-out flow controller 14 installed upstream from the regeneration flow passage 83, a back pressure valve 15 installed downstream from the regeneration flow passage 83, a check valve 13, and a non-regeneration operation relief valve 16 opened when the pressure of the meter-in flow passage becomes equal to or higher than set pressure. The set pressure is not less than a sum of a minimum set pressure of the back pressure valve 15, an inlet-outlet pressure difference of the meter-out flow controller 14 when the meter-out flow rate is maximum and the discharge flow rate of the hydraulic pump 2 is maximum, and an actuator pressure difference necessary for driving the hydraulic actuator 4 with no load, and not less than a maximum set pressure of the back pressure valve 15. <P>COPYRIGHT: (C)2013,JPO&INPIT |
