The utility model discloses a carbon dust structure is prevented to direct current motor armature tip belongs to the motor field, including direct current motor's commutator and several armature coil, the commutator is equipped with several rising piece, includes still that first no latitude area and second do not have the latitude area, and first no latitude area edge circumference twines in all armature end winding outsides, first no latitude area sets up two along axial at least interval, is equipped with the clearance that is used for the air -out between adjacent two first the nos latitude areas, every rising piece outward all the cladding have a U type composite insulating foils, the outside top -coat of U type composite insulating foils is equipped with the epoxy layer, the second does not have the latitude area and twines the outside at all U type composite insulating foilss in proper order along the circumference, the second does not have the latitude area and is equipped with the clearance that is used for the air -out between rather than adjacent first no latitude area yet. One kind can be good the insulation of assurance armature tip and rising piece junction, prevent that armature end winding from blowing the carbon dust structure is prevented to direct current motor armature tip of accident.