Patent ID: 7902709
Filing Date: 2011-03-08
Classification: H02K

Abstract:
1. A brush-less motor comprising: an annular stator; and a rotor disposed inside the stator and being rotatable relative to the stator, the rotor including a single annular permanent magnet having a plurality of poles that are alternated in the circumferential direction of the permanent magnet and are magnetized in the axial direction of the permanent magnet, wherein the stator includes: a plurality of teeth parts that are arranged at equal intervals along a circumferential direction of the stator and extend toward the rotor, respectively; and an annular yoke part that connects the plurality of teeth parts together, wherein each of the teeth parts includes a central part that is central in an axial direction thereof and end parts that are respectively disposed at positions equally spaced from the central part, wherein a sectional shape of each of the end parts in a direction perpendicular to the axial direction is different from a sectional shape of the central part in the direction perpendicular to the axial direction, and wherein each of the poles has: a first axial part extending from an axial central part of the permanent magnet to one axial end part of the permanent magnet; and a second axial part extending from the axial central part of the permanent magnet to the other axial end part of the permanent magnet; wherein the first axial part and the second axial part are shifted from each other by a predetermined angle in the circumferential direction of the permanent magnet at the axial central part.