| 摘要 |
A motor unit includes a rotating portion and a stationary portion. The rotating portion includes a shaft, a rotor hub, and a rotor magnet. The rotor hub includes a top plate portion and a cylindrical portion. The stationary portion includes a sleeve and an armature. The armature is arranged radially opposite the rotor magnet. A lubricating fluid is arranged between an outer circumferential surface of the shaft and an inner circumferential surface of the sleeve with at least one of the outer circumferential surface of the shaft and the inner circumferential surface of the sleeve including an upper radial dynamic pressure groove array and a lower radial dynamic pressure groove array. An axial position of a center of gravity of the rotating portion is arranged above an axial position of the lower radial dynamic pressure groove array. |
