Abstract: The present invention relates to a drum motor (1) comprising a driving member (7), a gear transmission and a driven member, said gear transmission being constructed as a plurality of planet transmissions (18, 20, 22) in the form of sun wheels (130) and planet wheels (144) arranged successively in the interior of an internally toothed rim (100), said driven member being in the form of a cylindrical drum (3) which contains the driving member (7) and the toothed rim (100), and which rotates about a longitudinal axis A. The invention is characterized in that the toothed rim (100) is formed by at least two juxtaposed ring-shaped segments (110, 115, 125) which provide a separate annulus for each planet transmission, and that member (120, 122, 200) are provided to secure the ring-shaped segments (110, 115, 125) against mutual rotation about the longitudinal axis A.