Patent ID: 6798093
Filing Date: 2004-09-28
Classification: H02K

Abstract:
A motor comprising:a cylindrical magnet of which an outer circumferential surface is divided into portions in a circumferential direction, which portions are alternately magnetized to different poles; first outer magnetic pole portions which are formed by gapping part of a cylinder from a distal end in an axial direction of said motor and oppose the outer circumferential surface of said magnet; second outer magnetic pole portions which are formed by gapping part of a cylinder from a distal end in an axial direction of said motor and oppose the outer circumferential surface of said magnet; first inner magnetic pole portions opposing an inner circumferential surface of said magnet; second inner magnetic pole portions opposing the inner circumferential surface of said magnet; a first coil which is located at a position between said first outer magnetic pole portions and said first inner magnetic pole portions in the axial direction of said magnet and excites said first outer magnetic pole portions; a second coil which is located at a position between said second outer magnetic pole portions and said second inner magnetic pole portions on an opposite side to said first coil in the axial direction of said magnet and excites said second outer magnetic pole portions; and an annular member which is in contact with the inner circumferential surface of said magnet and fits with at least said first inner magnetic pole portions or second inner magnetic pole portions.