Reduction gear and gear motor

A geared motor comprising:

• an electric motor having a motor output shaft;
• and
• a reduction gear unit comprising:
• a housing;
• a first gear stage;
• and
• a second gear stage, the second gear stage having an externally toothed first gearwheel and an internally toothed second gearwheel which meshes with the first gearwheel and is at least indirectly connected fixedly to an output so as to rotate with the output;
• a circulating eccentric which is driven by the first gear stage for driving a relative rolling movement of the second gearwheel on the first gearwheel, the first gearwheel being moved by the eccentric on a circular path;
• and
• a torque support disk arranged axially next to the first gearwheel and preventing the first gearwheel from performing a relative rotation with respect to the housing, the first gearwheel having at least one guide pin which engages into a guide groove of the torque support disk, or the torque support disk having at least one guide pin which engages into a guide groove of the first gearwheel, wherein the first gearwheel has at least one cam which projects in the axial direction from a main body of the first gearwheel and bears against the torque support disk in such a way that the at least one guide pin does not engage completely into the guide groove, or in that the torque support disk has at least one cam which projects in the axial direction from a main part of the torque support disk and bears against the first gearwheel in such a way that the at least one guide pin does not engage completely into the guide groove, wherein the first gear stage comprises a worm, which is connected fixedly to the motor output shaft so as to rotate with the motor output shaft, and a worm gear.