A driving device includes an electric motor including a stator and a rotor rotatable relative to the stator, and a gear train connected to the rotor. The stator includes a cylindrical housing and an endcap mounted to an end of the housing; The gear train includes a gear mechanism with at least one stage, which includes a ring gear, a sun gear, planetary gears and a carrier. The ring gear is directly engaged with the endcap, which limits the position of the planetary gears of the gear train in an axial direction of the gear train.