| 摘要 |
The invention relates to a gas exchange valve actuator for axial displacement of a gas exchange valve of a combustion engine. The actuator is configured to be connected to a pressure fluid source (HP) and a pressure fluid sink (LP), respectively, and is configured to be driven by a gaseous pressure fluid and comprises an actuator piston (8) comprising an actuator piston disc (4) and an actuator piston rod (7) projecting from the actuator piston disc (4) in the axial direction, a cylinder volume, the actuator piston disc (4) separating said cylinder volume in a first part (5) and a second part (6) and being displaceable back and forth in the axial direction in said cylinder volume between an inactive position and an active position, the first part (5) of the cylinder volume being configured for controllable fluid communication with said pressure fluid source (HP) and said pressure fluid sin (LP), respectively, and a hydraulic circuit comprises a chamber (18), the free end (19) of the actuator piston rod (7) being arranged in said chamber (18), wherein the actuator piston rod (7) is displaceable back and forth in the axial direction in a channel (10) in connection with axial displacement of the actuator piston disc (4) in the cylinder volume, said channel (10) extending between the first part (5) of the cylinder volume and the chamber (18) of the hydraulic circuit. The actuator is characterized in that said channel (10) comprises at least one circumferential ventilation groove (22) that is configured to be connected to said pressure fluid sink (LP). |
