Patent ID: 7917918

Claim:
A brushless motor having a chucking mechanism operable to detachably place thereon an optical disk including a central opening portion, the brushless motor comprising: a shaft being a central axis; a rotor magnet rotating along with the shaft; and a rotor holder including therein a cylindrical portion retaining the rotor magnet and a flat lid portion extending from the cylindrical portion to the shaft, wherein the chucking mechanism is arranged on a top surface of the lid portion, and the chucking mechanism includes: a cone shaped member having a slidable portion of a substantially cylindrical shape with an inner circumferential surface movable in an axial direction with respect to the shaft, and a disk contacting portion of a substantially annular shape expanding downwardly in the axial direction making contact with an inner circumferential surface of the central opening portion; a turn table member having a disk mounting surface making contact with a bottom surface of the optical disk, a hollow portion arranged axially below the disk mounting surface, having a substantially annular shape with an opening facing downward, an inner circumferential wall and an outer circumferential wall, and at least one balance member accommodated in the hollow portion; an elastic member, arranged at an axial space between the turn table member and the cone shaped member, retaining an axial position of the cone shaped member; and a yoke member arranged axially above the slidable portion restricting axial movement of the cone shaped member, and wherein an outer circumferential surface of the outer circumferential wall is arranged radially at a same position as the cylindrical portion or radially inward of the cylindrical portion, wherein an adhesive is arranged at an axial space between the turn table member and the rotor holder, the turn table includes, at a portion thereof opposite to the top surface of the lid portion, a hollow portion having an opening facing axially downward, and an adhesive is arranged between the top surface of the lid portion and the hollow portion.