A rotary drive, with a drive element, with an outer tube, with an end piece mounted and able to rotate in relation to the outer tube and unable to shift axially, with a helical slider arranged able to move axially in the outer tube but not rotate, with a helical shaft arranged axially parallel in the outer tube, which interacts by a steep thread with a thread profile of the helical slider, wherein the relative axial movement of helical slider and helical shaft brought about by the drive element is transformed into a relative rotation of outer tube and end piece, wherein the drive element is arranged coaxially inside the outer tube, the helical shaft and the thread profile of the helical slider are arranged coaxially in the outer tube, and the end piece is mounted coaxially in at least one end of the outer tube.