Abstract: A motor includes a coming-off preventing portion including an inner circumferential edge defining a through hole, inside which a substantially cylindrical bearing housing is inserted, and being arranged axially above an insulator. The inner circumferential edge has at least two different radial dimensions. A boss portion includes a columnar portion inserted inside the through hole, and a collar portion extending radially outward from a lower end of the columnar portion. The collar portion includes an outside surface having at least two different radial dimensions, and an upper surface arranged axially opposite a bottom portion of the inner circumferential edge. The radial dimensions of the inner circumferential edge and those of the collar portion are arranged to allow the collar portion to be axially inserted through the inner circumferential edge only when the inner circumferential edge and the collar portion are arranged in a predetermined circumferential orientation relative to each other.

Abstract: An electric motor includes a stator portion, a rotor portion, and a bearing mechanism, wherein the rotor portion includes a rotor holder having a substantially cylindrical shape with a closed end, and a field magnet fixed to an inner circumference of the rotor holder; the stator portion includes a stator, a base portion to which the stator is fixed, and a magnetic member; and the magnetic member includes a cylindrical portion having a substantially cylindrical shape into which a lower end portion of an insulator of the stator is inserted, the lower end portion being a portion of an outer portion of the insulator and opposing the base portion, and a flat portion having a substantially annular shape which spreads outwardly in a radial direction from a lower edge of the cylindrical portion and opposes a lower edge of the field magnet.

Abstract: A motor includes a coming-off preventing portion including an inner circumferential edge defining a through hole, inside which a substantially cylindrical bearing housing is inserted, and being arranged axially above an insulator. The inner circumferential edge has at least two different radial dimensions. A boss portion includes a columnar portion inserted inside the through hole, and a collar portion extending radially outward from a lower end of the columnar portion. The collar portion includes an outside surface having at least two different radial dimensions, and an upper surface arranged axially opposite a bottom portion of the inner circumferential edge. The radial dimensions of the inner circumferential edge and those of the collar portion are arranged to allow the collar portion to be axially inserted through the inner circumferential edge only when the inner circumferential edge and the collar portion are arranged in a predetermined circumferential orientation relative to each other.

Abstract: An electric motor includes a stator portion, a rotor portion, and a bearing mechanism, wherein the rotor portion includes a rotor holder having a substantially cylindrical shape with a closed end, and a field magnet fixed to an inner circumference of the rotor holder; the stator portion includes a stator, a base portion to which the stator is fixed, and a magnetic member; and the magnetic member includes a cylindrical portion having a substantially cylindrical shape into which a lower end portion of an insulator of the stator is inserted, the lower end portion being a portion of an outer portion of the insulator and opposing the base portion, and a flat portion having a substantially annular shape which spreads outwardly in a radial direction from a lower edge of the cylindrical portion and opposes a lower edge of the field magnet.