Patent ID: 8179011
Filing Date: 2012-05-15
Classification: H02K

Abstract:
1. A brushless motor comprising a stator including a plurality of teeth around which coils are wound, and a rotor, which is rotatably arranged radially inward of the stator, wherein the rotor includes a plurality of magnetic pole portions that face the teeth, wherein the magnetic pole portions are formed by permanent magnets arranged at equal angular intervals in the circumferential direction to have the same polarities as each other, the rotor includes gaps that function as magnetic resistance at circumferential ends of each of the magnetic pole portions so that an iron core portion is formed between circumferentially adjacent magnetic pole portions, and magnetic flux of the magnetic pole portions passes through the iron core portion along the radial direction, wherein the rotor is structured such that the rotation direction is defined to be one direction, and wherein the gaps formed on the circumferential ends of each of the magnetic pole portions include a first gap located on the leading end of the magnetic pole portion in the rotation direction of the rotor and a second gap located on the trailing end of the magnetic pole portion in the rotation direction of the rotor, and the circumferential width of the first gap is set to be greater than the circumferential width of the second gap.