Patent ID: 7928629
Filing Date: 2011-04-19
Classification: H02K

Abstract:
1. A direct current motor, comprising: a stator having four or more magnetic poles; an armature which is rotatable relative to the stator, the armature having an armature core and a commutator which rotate integrally, wherein the armature core has a plurality of teeth and a plurality of coils which are respectively wound around the teeth, the commutator has a plurality of segments arranged in a circumferential direction, and a short-circuit conductor for short-circuiting predetermined segments from among the segments, wherein each of the segments has an angular width WS, and there is a gap of an angular width WU between each adjacent pair of the segments; and an anode brush and a cathode brush which contact and slide against each of the segments when the commutator rotates, wherein a substantial angular width WB of each of the anode brush and the cathode brush satisfies (n−1)(WS+WU)+WU<WB<n(WS+WU)+WU, where n is an integer no less than two, wherein the coils are each connected to corresponding one of the segments to form n closed loops, wherein each of the n closed loops passes through the corresponding segments and the short-circuit conductor and are electrically independent of each other, wherein coils which respectively correspond to different closed loops are each cyclically connected to segments which are adjacent to each other in the circumferential direction, and wherein each of the anode brush and the cathode brush is adapted to contact always with all closed loops.