Hydraulic drive system for a stage with adjustable speed hydraulic pump as control element

摘要

The system has a check valve unit (90) arranged between an actuator and a controlling element, so that the check valve unit selectively blocks fluid flow i.e. oil flow, from the actuator to a storing unit. The controlling element includes a hydraulic pump (75) that is operated as a hydraulic motor, where the hydraulic pump stands in rotational drive-connection with an electric motor (76). The electric motor is connected with a rotational speed controlling unit (80) that adjusts a rotational speed of the electric motor to a predetermined target value.