A rotary actuator including a hydraulic valve including a borehole with shoulders, and a first operating connection and a second operating connection originating from the borehole, wherein a pressure balanced hollow piston is arranged axially movable in the borehole, wherein the hollow piston is fitted with a first outer diameter in a borehole section in a sealing manner, wherein the hollow piston includes the following axially subsequent to the first outer diameter: an enveloping surface with a large outer diameter in an axial portion of the first operating connection, and an enveloping surface with a small outer diameter in an axial portion of the second operating connection, wherein an inlet edge and an outlet edge extends from each of the first enveloping surface and the second enveloping surface, wherein the two inlet edges are oriented away from one another and the two outlet edges are oriented towards one another.