Patent ID: 8274193
Filing Date: 2012-09-25
Classification: H02K

Abstract:
1. An electric motor comprising: a rotational shaft rotatably supported by a yoke having a plurality of magnetic poles; a plurality of teeth attached to the rotational shaft and extending in a radial direction to allow windings to be wound therearound; an armature core formed between the teeth and provided with a plurality of slots which extend in an axial direction; a commutator installed on the rotational shaft adjacent to the armature core and having a plurality of segments which are disposed in a circumferential direction; and a short-circuit member which short-circuits the segments having the same potential, among the plurality of segments, wherein the number P of magnetic poles, the number Sr of the slots, and the number Se of the segments are set in order to satisfy when A is a natural number of 2 or more; the number of the magnetic poles is P, the number of the slots is Sr, and the number of the segments is Se, and the windings wound around each of the teeth form two coil groups of three-phase concentrated windings which are disposed point-symmetrically to each other with respect to the rotational shaft, wherein each of the coil groups includes a first coil, in which the windings are wound around the teeth in a forward direction, and a second coil, in which the windings are wound around the teeth in a reverse direction, and when each of the teeth is allocated with a U phase, a V phase, and a W phase in this order in a circumferential direction so that the first coil wound for each phase is set to be coils of the U phase, the V phase, and the W phase, and the second coil wound for each phase is set to be coils of the −U phase, the −V phase, and the −W phase, the coils of the U, −W, V, −U, W and −V phases are electrically connected between the adjacent segments in this order.