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 (13, 20) 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 (13, 20) 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.