A drive system, having an electric motor, a gear unit and an adapter having a fan , wherein the adapter in turn has an adapter housing part , wherein a rotor shaft of the electric motor is connected to, in particular is inserted in, a coupling arranged in the adapter, wherein the coupling is connected to, in particular is inserted in, an input shaft of the gear unit, wherein the fan is connected non-rotatably to the coupling , in particular is mounted on the coupling , wherein the adapter housing part has an end region which faces away from the electric motor in the axial direction and is formed as a nozzle region such, wherein the air flow conveyed by the fan flows out of the adapter housing part in the axial direction, in particular along a housing region of the gear unit, in particular wherein the axial direction is oriented parallel to the direction of the axis of rotation of the coupling , and wherein the adapter housing part has an inner ring-like structure and an outer ring-like structure, characterised in that the inner ring-like structure is connected to the outer ring-like structure via first and second cooling fins which are in particular regularly spaced apart from each other in the circumferential direction, with the outer ring-like structure bearing the nozzle region , with the inner ring-like structure being arranged radially within the outer ring-like structure, with the first cooling fins in each case having a lesser wall thickness in the circumferential direction than the second cooling fins , with first cooling fins being arranged in the circumferential direction between two second cooling fins which are in each case next adjacent to each other, and with the outer ring-like structure having radially continuous cutouts as air inlet openings for the air flow conveyed by the fan . wherein the adapter in turn has an adapter housing part , wherein a rotor shaft of the electric motor is connected to, in particular is inserted in, a coupling arranged in the adapter, wherein the coupling is connected to, in particular is inserted in, an input shaft of the gear unit, wherein the fan is connected non-rotatably to the coupling , in particular is mounted on the coupling , wherein the adapter housing part has an end region which faces away from the electric motor in the axial direction and is formed as a nozzle region such, wherein the air flow conveyed by the fan flows out of the adapter housing part in the axial direction, in particular along a housing region of the gear unit, in particular wherein the axial direction is oriented parallel to the direction of the axis of rotation of the coupling , and wherein the adapter housing part has an inner ring-like structure and an outer ring-like structure, characterised in that the inner ring-like structure is connected to the outer ring-like structure via first and second cooling fins which are in particular regularly spaced apart from each other in the circumferential direction, with the outer ring-like structure bearing the nozzle region , with the inner ring-like structure being arranged radially within the outer ring-like structure, with the first cooling fins in each case having a lesser wall thickness in the circumferential direction than the second cooling fins , with first cooling fins being arranged in the circumferential direction between two second cooling fins which are in each case next adjacent to each other, and with the outer ring-like structure having radially continuous cutouts as air inlet openings for the air flow conveyed by the fan . <EOS>