Actuator having protected screw mechanism, and brake calliper comprising such actuator

Electric actuator (13), comprising a housing (7) which contains a screw mechanism (11) and an electric motor (5) which is driveably connected to the screw mechanism (11) which provides a linear movement in response to a rotational movement of the electric motor (5), said screw mechanism (11) comprising a screw (12) and a nut (33) one of which is supported rotatably with respect to the housing (7) by means of an angular contact ball bearing (31), said screw (12) by means of an intermediate coupling element (18) engaging an actuating member (16) for transferring axial forces, said intermediate coupling element (18) engaging the screw (12) by means of an axial connection (53, 54) which allows radial movements, the intermediate coupling element (18) and the screw (12) engage each other by means of essentially radial surfaces (53, 54), which surfaces are mutually radially displaceable, characterized in that the actuating member (16) and the intermediate coupling element (18) engage each other through corresponding convex and concave surfaces.