Abstract: An electromechanical transmission and/or clutch actuator includes an electric motor for generating a driving rotational movement of a motor shaft, and elements for transmitting the driving rotational movement via a flexible drive from the electric motor to a spindle drive configured to convert the rotational movement to an axial actuation movement. The elements for transmitting the driving rotational movement may include a driving element such as a driving pulley or gear connected coaxially to the motor shaft, a driven element wheel such as a driven pulley or gear connected to the spindle drive, and a flexible element such as a drive belt which transfers the driving rotational movement from the motor shaft to the spindle drive.

Abstract: An anti-rotation safeguard of an axially moving element is provided with an anti-rotation safeguard, the anti-rotation safeguard being suited for use in a ball screw drive in an automated manual transmission. The ball screw has nut which rotates on balls on a spindle, at least one securing element protruding radially from the spindle, and at least one guide element with a longitudinal a groove which guides the securing element. During translation of the spindle, rotation of the spindle is prevented by the securing element in the guide element groove. The guide element is accommodated in a cutout of the ball screw drive enclosure and can rotate about its longitudinal axis so that force transfer from the securing element to the groove is over a large surface area to reduce wear of the groove and of the securing element.