ROTATION-TYPE WORKING MACHINE

摘要

Provided is a rotation-type working machine having high energy recovery efficiency and safe. The rotation-type working machine is provided with: a lower travel body; an upper rotation body; a hydraulic motor (11) for rotationally driving the upper rotation body; a hydraulic pump (10); a rotation operation device (12); a control valve (13) for controlling the hydraulic motor (11) on the basis of an operation signal from the rotation operation device (12); conduits (14, 15) connecting the hydraulic motor (11) and the control valve (13); a pilot hydraulic pressure source (28); communication valves (25, 26) which can, by a pilot pressure, switch between the connection between a tank (T) and the conduits (14, 15) and the interruption of the connection; an electric motor (29); an electricity storage device (30); communication switching valves (32, 33) provided on the primary side of the communication valves (25, 26); a switching control valve (41) provided on the primary side of the communication switching valves (32, 33); and a controller (27). When reducing the speed of rotation, the controller (27) issues a command which switches the switching control valve (41) to a connection position and which switches the communication switching valves (32, 33) to a pilot pressure supply position. In a state in which rotation is stopped, the controller (27) issues a command which switches the communication switching valves (32, 33) to a closed position, and also issues a command which switches the communication valves (25, 26) to a communication closed position.