Patent attributes
A pressure selector valve (13) is provided between a hydraulic motor (1) and a directional control valve (5) to connect one of the main conduits (4A), (4B) on a high pressure side to a high pressure conduit (14) while connecting the other of the main conduits on a low pressure side to a low pressure conduit (15). As an inertial body approaches a stop position, a spool valve (16) is switched to an open position (e), bringing a branch passage (14A) of the high pressure conduit (14) into communication with the low pressure conduit. When the pressure difference between the main conduits becomes small, the pressure selector valve is automatically returned to a neutral position to cut off communication between the main conduits, suppressing a reversing movement of the hydraulic motor so that an inertial body can be brought to a stop smoothly.