HYDRAULIC DRIVE OF MACHINERY

摘要

[Problem] To rapidly stop a rotary part even though a relief pressure is lowered due to a fault of a hydraulic device included in a rotary motor driving circuit when it is intended to stop the rotary part after a predetermined delay time from the time a rotary manipulation tool is put into neutral. [Solution] A hydraulic drive of the present invention comprises: a first choke (34) for controlling a parking brake (29) by applying a braking force to a rotary motor (16) after a predetermined delay time (T) from the time when a rotary manipulation tool (15) is put into neutral in a state where the rotary manipulation tool (15) is connected to a pilot pump (12); and an on-off valve (36) and a second choke (37) for controlling the parking brake (29) by applying a braking force to the rotary motor (16) after a delay time (t) shorter than the predetermined delay time (T) when the rotary manipulation tool (15) is put into neutral but the rotary manipulation tool (15) is disconnected from the pilot pump (12).