| 摘要 |
The invention relates to an actuator for axial displacement of an object, the actuator comprises an actuator piston disc (4) and an actuator piston rod (7), which together form an actuator piston, a cylinder volume, the actuator piston disc (4) dividing said cylinder volume into a first part (5) and a second part (6) and being displaceable in said cylinder volume between an inactive and an active position, a pressure fluid circuit (10) arranged for controllable fluid communication with the first part (5) of the cylinder volume, and a first hydraulic circuit (21) comprising a liquid-filled space (22), the actuator piston rod (7) being disposed to be axially displaced in relation to said liquid- filled space (22) in connection with axial displacement of the actuator piston disc (4) in the cylinder volume. The actuator piston comprises a second hydraulic circuit (24), the liquid-filled space (22) being in fluid communication with an inner cavity (25) in the second hydraulic circuit (24) when the actuator piston disc (4) is in said inactive position, said inner cavity (25) partly being delimited by a positioning piston (29), which is displaceable in relation to the actuator piston and which is arranged to abut against said object in the second part (6) of the cylinder volume, the second hydraulic circuit (24) comprising a valve (27) that is disposed to prevent fluid flow from the inner cavity (25). |
