Device for controlling driving speed of mobile working machine, has pressure valve connected upstream of throttle valve, where side of pressure valve is charged with pressure resting after throttle valve in flowing direction of fluid

摘要

The device has a control valve (6) connected upstream of a hydraulic motor (5), and a pressure valve (7) connected upstream of the control valve. Another pressure valve (9) is fixed in a return pipe (15) and connected upstream of a throttle valve (8) that is variable in throttling effect. A side of the latter valve acting in a closing direction is charged with pressure resting before the throttle valve in a flowing direction of hydraulic fluid. Another side of the latter valve acting in an opening direction is charged with pressure resting after the throttle valve in the flowing direction.