Electromagnetic micromotor for use in watch movements of small dimensions

An electromagnetic micromotor of the type comprising;

• a rotor constituted by a permanent magnet at least partially embedded in an overmolding formed from a plastic material, such overmolding including a mechanical coupling means for a mechanism to be driven,
• a cage including an interior cavity defined therein by a peripheral wall and a bottom integral with said peripheral wall, said interior cavity being closed by a cover inset into the cage to house therein said rotor which is freely mounted in rotation within said cavity, said bottom having a notch to open said cavity outwardly in order to enable said mechanical coupling means of said overmolding of said rotor to mesh with said mechanism to be driven, and
• first and second rotation guide means for guiding the rotor in rotation within the cage, said first and second rotation guide means being arranged on the overmolding of said rotor as well as respectively on the bottom and on the cover of said cage, said first and second rotation guide means being constituted, on the rotor, by two housings arranged coaxially in said overmolding of plastic material, and on the cage by two spindles or pivots which project inwardly, within the interior cavity and which are respectively fixed on the bottom and the cover of the cage and at least one said spindle or pivot is accommodated in one of the aforesaid housings, the spindle or pivot of said first guide means and said cage bottom comprising a monolithic structure and said notch comprising a machined face provided close to said spindle or pivot of said first rotation guide means.