Operating unit with a screw, a planetary gear and a influenced by this actuator

Disclosed is an actuating unit which can be used for an electromechanically actuatable disk brake for motor vehicles, essentially comprising a drive unit (1) or an electric motor (11), and an actuating element (7) which is used to cause two friction linings (4,5) which are displaceably arranged in a brake caliper to engage with a brake disc, in addition to a first and second reduction gear (2,3). Force is transmitted between the planetary cage (34) of the planetary gear (30-34) and the threaded spindle (17 or 22) of the ball screw (16-18) by means of a coupling shaft (40), whereby the ends thereof form universal joints (41,42) with the planetary cage (34 or 49) and the threaded spindle (22).