| 主权项 |
1. An inner-rotor motor comprising:
an upper bearing and a lower bearing; a shaft supported by the upper and lower bearings to be rotatable about a rotation axis extending in a vertical direction; a rotor magnet directly or indirectly fixed to the shaft; a stator arranged radially outside and opposite to the rotor magnet with a gap intervening therebetween; an upper bracket configured to hold the upper bearing; and a lower bracket configured to hold the lower bearing; wherein the stator includes a stator core, an insulator, and windings wound around the stator core with the insulator intervening therebetween; the upper bracket includes an upper cylindrical cover press fitted to an outer circumference of the stator core from above, an upper bearing holding portion extending in an axial direction and configured to hold the upper bearing, and a top plate portion configured to join the upper cylindrical cover and the upper bearing holding portion to each other; the lower bracket includes a lower cylindrical cover press fitted to the outer circumference of the stator core from below, a lower bearing holding portion extending in the axial direction and configured to hold the lower bearing, and a bottom plate portion configured to join the lower cylindrical cover and the lower bearing holding portion to each other; each of the upper and lower brackets is press fitted to the stator core; and the inner-rotor motor further comprises a preload member axially adjacent to one of the upper and lower bearings to apply a preload in accordance with a relative distance between the upper and lower brackets to each of the upper and lower bearings, wherein each of the upper and lower bearings include an outer race, an inner race, and two or more rolling elements held between the inner and outer races. |
