A drum motor optimized for the hygienic requirements in the food industry; in particular the drum motor is used for driving conveyor belts. One embodiment of the invention discloses a drum motor comprising a drum shell accommodating a geared rim secured to the drum shell, a first inner end cap attached to the geared rim, a second inner end cap attached to a locking flange having an expanding element adapted to secure the second inner end cap to the drum shell when attaching the second inner end cap to the locking flange.