An actuator for a hydraulic valve for a cam phaser, the actuator comprising a magnetisable actuator housing that envelops a magnet coil; a pole group that is arranged in a housing receiver opening of the magnetisable actuator housing, wherein the pole group includes a pole core and a pole tube, wherein the pole core and the pole tube are connected by a connection bar and the pole core is connected with the connection bar by a pole core cone, or the pole tube is connected with the connection bar by a pole tube cone, wherein an armature is received axially movable in an inner space of the pole group.