Abstract: A screw actuator (4) comprises a housing (1), a nut (5) and a screw (6) one of which is axially fixed with respect to the housing and the other of which is axially displaceable with respect to the housing for moving an head (21), as well as a motor (7) which comprises a stator (8) connected to the housing, and a rotor (9) which is drivingly connected to a rotatable part (6) of the screw actuator, the housing having a bore (10) accommodating at least the nut and/or screw, an axially fixed part of said nut or screw being supported with respect to a radial support abutment (11) which extends inwardly in the bore. The rotor of the motor is supported rotatably on a sleeve (13), said sleeve engaging the fixed part and extending away from the brake pad, said sleeve having a radially outwardly extending sleeve flange (14) which is interposed between said support abutment, and the axially fixed part.

Abstract: A one-way clutch including at least two concentric rings one of the rings carrying at least one ratchet pawl, and the other of the rings including ratchet teeth which engage the at least one ratchet pawl so as to allow relative rotational movement of the at least two rings in one rotational direction, and to provide a clutch between those rings in the operate rotational direction. At least one of the rings includes two identical half rings which are connected to each other and which at least partly enclose the other rings at axially opposite ends.