Patent ID: 8013489
Filing Date: 2011-09-06
Classification: H02K

Abstract:
1. A small DC motor, comprising: a motor frame having a constant thickness and having two ends and a side wall; wherein the side wall surrounds a magnet and includes four straight portions and at least four connecting portions, the motor frame being a magnetic material and being a magnetic constituent portion of the motor; wherein each of the connecting portions is located between adjacent two of the four straight portions; wherein the magnet includes at least four poles and has an outer surface conforming to the motor frame and an inner surface forming a circular opening and wherein the width of the magnet between the inner and outer surface varies; a rotor having a shaft and rotatably disposed in the circular opening, wherein the side wall includes the same number of connecting portions as the number of poles contained in the magnet, wherein each of the connecting portions is a segment of a circle concentric with a center of the shaft; wherein an air gap provided between the inner surface of the magnet and the rotor has a constant distance.