Patent attributes
There is provided a hydraulic drive device for a working machine with which a number of times of maintenance can be reduced. A controller (20) opens a first on-off valve (25a), closes a second on-off valve (25b), switches a first directional switching valve (30a) to a first position (A), and switches a second directional switching valve (30b) to a third position (C), thereby pressure oil from a hydraulic pump (1a) is supplied from the first on-off valve to an actuator (5a) through the first directional switching valve. When history data of the first on-off valve is determined to satisfy a prescribed condition, the controller closes the first on-off valve, opens the second on-off valve, switches the first directional switching valve to a second position (B), and switches the second directional switching valve to a fourth position (D), thereby pressure oil from the hydraulic pump is supplied from the second on-off valve to the actuator through the second directional switching valve. For example, the controller determines that the prescribed condition is satisfied when an operation number of times of the first on-off valve reaches a first prescribed value.
