Patent ID: 7619337

Claim:
A brushless motor comprising: a rotor having a magnet, the magnet including north and south magnetic pole pairs which are alternately arranged in a direction of rotation; a stator having coils provided so as to face the magnet, wherein the rotor is rotated by supplying a current to the coils of the stator; and a housing made of magnetic material, wherein the housing comprises: protruding portion provided integrally with the housing so as to face the magnet and protrude toward the magnet, and an opening facing the magnet, wherein the protruding portion and the opening has a positional relationship therebetween, such that when the protruding portion is positioned corresponding to a center of the magnetic pole of said magnetic pole pairs, the opening is positioned corresponding to a boundary between the magnetic poles of said magnetic pole pairs, and wherein the protruding portion and the coils has a positional relationship therebetween, such that when the protruding portion is positioned corresponding to the center of the magnetic pole of said magnetic pole pairs, both ends of the coils are positioned corresponding to positions other than the boundary between the magnetic poles of said magnetic pole pairs.