A motor-gearbox assembly includes a housing, a motor, and a gearbox. The housing includes a first alignment mechanism and a second alignment mechanism. The first alignment mechanism is at a first end of the housing and the second alignment mechanism is at a second end of the housing. The motor is mechanically positioned within the housing in accordance with the first alignment mechanism. The gearbox is mechanically positioned within the housing in accordance with the second alignment mechanisms to mechanically couple to the motor.

A transmission system includes a first gear which has an outer toothing; a plurality of pinions which mesh with the outer toothing of the first gear, each pinion being connected to an electric machine which is designed as a motor or a generator; a second gear which is coaxially connected to the first gear and which has an outer toothing; a plurality of third gears which mesh with the second gear and which have an outer toothing, each of the third gears being coaxially connected to a fourth gear which has an outer toothing; and a fifth gear which meshes with the fourth gears, which is connected to a drive or output shaft, and which has an outer toothing, with the first gear and the drive or output shaft being coaxially arranged.

A housing accommodates a motor and a deceleration mechanism. The deceleration mechanism includes a support axis extending perpendicularly to an output shaft of the motor. The housing includes a case and a cover. The case is in a bottomed tubular shape to have an accommodation chamber and a holder portion. The holder portion surrounds a bottom of the accommodation chamber and is in contact with the motor. The cover is mounted to the case to surround an opening of the case and to form a hollow portion with the holder portion to accommodate at least the motor. The motor and the deceleration mechanism are mountable into the accommodation chamber through the opening in one direction from a side of a mounting surface of the case, on which the housing is to be affixed to a support portion of an affixing member.