Patent ID: 7459813

Claim:
A magnet rotor comprising: a rotary shaft; a hollow cylindrical permanent magnet having a center, in which the rotary shaft is disposed, the permanent magnet having a first fitting part formed in an upper end face in a direction of the rotary shaft and composed of one of a protrusion and a concave groove; a driving arm rotating around the rotary shaft integrally with the permanent magnet, the driving arm having a second fitting part formed therein and composed of a protrusion or concave groove to mate with the first fitting part; and a pair of upper and lower rotor supporting members supporting a rotor assembly including the rotary shaft, permanent magnet, and driving arm; wherein a depth of fitting between the first and second fitting parts is set so that a length of a combination of the permanent magnet and driving arm is longer than a length of a distance between a pair of upper and lower supporting faces formed on the paired rotor supporting members when the rotor assembly is supported between the paired upper and lower supporting faces.