Linear actuator with deaeration of the extension arm by way of a check valve

Abstract

An actuator includes a housing, an extension arm, and a threaded spindle. The threaded spindle is rotatably supported on the housing with respect to the center axis of the threaded spindle. The extension arm projects slidably out of the housing in the direction of the center axis. The housing and the extension arm together surround an interior space, whose volume changes as the extension arm moves. One end of the threaded spindle projects into a tubular portion of the extension arm, regardless of the position where the extension arm is located. The tubular portion extends about the central axis with a constant internal cross-sectional shape. The end of the threaded spindle is connected to a piston, which divides the internal space into a first region and a second region such that the first and second regions are separated from each other in a fluid-tight manner. The first region is only delimited by the piston and the extension arm. The second region is sealed against the environment in a fluid-tight manner. A check valve is arranged between the first region and the second region in the piston. The check valve passes fluid in a first direction from the second region to the first region of the extension arm and blocks the passage of fluid in a second direction opposite to the first.