Transmission housing, gearbox and wheeled vehicle provided with such a gearbox

A transmission housing which can be coupled to the motor shaft of an electric motor to form a geared motor unit, said transmission housing comprising:

• a housing body defining a cavity, and, housed at least partially inside the cavity;
• a rotary driving element,
• an output shaft, and
• a device for transmitting the rotational movement of the rotary driving element to the output shaft,
• wherein the rotary driving element is supported inside the cavity of the housing body by one or more guide members and comprises a wall and two coaxial helical toothsets made in one piece with the wall and arranged on either side of said wall,
• the or at least one of the guide members is a rolling-contact bearing housed in a thickness of the rotary driving element, inside a recess of the rotary driving element and is surrounded by one of the toothsets of said rotary drive element, said recess is delimited by a circular lateral partition coaxial with said one of the toothsets, the circular lateral partition and the one of the toothsets delimit between them an annular space, wherein one of the two coaxial toothsets of the rotary driving element is on an annulus having an internal and an external circumferential surface, wherein said one of said toothsets on said annulus is disposed on the internal circumferential surface thereof.