Patent ID: 8653707

Claim:
A motor comprising: a shaft; a bearing arranged to support the shaft such that the shaft is rotatable about a central axis; a rotating body fixed to the shaft, the rotating body comprising a lid portion having an upper surface extending radially from the shaft to a first edge; a cylindrical portion extended from the first edge to a second edge, the cylindrical portion having an outer circumference, the cylindrical portion forming an inner space, a part of the bearing being housed inside the inner space; and a rotor magnet provided on the outer circumference; a stator arranged radially outward of the rotor magnet; a circuit board fixed to the stator, the circuit board arranged to be perpendicular to the central axis, the circuit board placed on one axial side of the rotating body such that the circuit board is closer to the lid portion than to the second edge; and an encoder arranged to detect rotation of the rotating body; wherein the encoder includes: a reflection pattern arranged on or above the upper surface of the lid portion of the rotating body which is opposed to the circuit board, wherein a portion of the reflection pattern is defined by a surface of a magnet provided on the lid portion of the rotating body; and a reflective rotation detection sensor arranged on the circuit board to detect the rotation of the rotating body by irradiating the reflection pattern with light, wherein the rotating body further includes a position detection-use magnet, the position detection-use magnet being annular and centered on the central axis, and arranged opposite the circuit board; wherein the circuit board has mounted thereon a position detection sensor arranged to detect magnetic field generated by the position detection-use magnet to detect a rotational position of the rotating body; and wherein a portion of the reflection pattern is defined by a surface of the position detection-use magnet.