Motor assembly with speed reducer

A motor assembly comprising:

• an electric motor having a rotating shaft;
• and
• a speed reducing mechanism configured to reduce a rotation speed of the rotating shaft of the electric motor and output a reduced rotation speed,
• the speed reducing mechanism including:
• a housing;
• an internal gear supported by an inner diameter surface of the housing;
• an eccentric disk capable of rotating inside the internal gear when the rotating shaft of the electric motor rotates;
• an output shaft having a cage at an axial end of the output shaft, wherein the cage is rotatably disposed between the internal gear and the eccentric disk, the cage being arranged coaxially with a rotation axis of the eccentric disk;
• and
• rolling elements retained by the cage and meshing with internal teeth of the internal gear, a number of the rolling elements being different from a number of the internal teeth,
• wherein the rolling elements are configured to mesh with the internal teeth successively due to rotation of the eccentric disk,
• whereby the output shaft is rotated at a reduced speed which is determined by a difference between the number of the internal teeth and the number of the rolling elements, per rotation of the eccentric disk,
• wherein the rotating shaft of the electric motor has an extended portion extended into the speed reducing mechanism,
• wherein the eccentric disk is mounted on the extended portion of the rotating shaft such that rotation of the rotating shaft is transmitted to the eccentric disk,
• wherein the electric motor and the speed reducing mechanism are mounted in a common housing,
• wherein the eccentric disk is rotatable relative to an input shaft, and
• wherein a torque limiter mechanism is provided between the eccentric disk and the rotating shaft, the torque limiter mechanism being configured to allow transmission of torque from the rotating shaft to the eccentric disk while the torque is not larger than a predetermined torque value, and to stop transmission of the torque if the torque exceeds the predetermined torque value.