Patent ID: 6603635
Filing Date: 2003-08-05
Classification: G11B,H02K

Abstract:
An inner rotor DC brushless motor structure having a shaft; a stator yoke surrounding an outer periphery of the shaft, a rotor magnet made of permanent magnets forming rotor magnetic poles on an outer periphery thereof and rotating centering around the shaft; a plurality of stator magnetic poles projecting inwardly from the stator yoke and a plurality of excitation switching position detecting sensors, the motor comprising:a plurality of long stator magnetic poles formed on long salient poles and a plurality of short stator magnetic poles formed on short salient poles having a shorter length than the long salient poles, numbers of the long stator magnetic poles and the short stator magnetic poles being equal to each other, the number of the long stator magnetic poles being equal to or larger than the number of phases of driving voltage, a number of turns of the decelerating coil being at least a number of turns of the driving coil, and a driving coil and a decelerating coil being wound around each of the plurality of long stator magnetic poles while the plurality of short stator magnetic poles being provided with no winding, wherein the rotor magnet being made up of the permanent magnets is disposed in a confronting relationship with the stator magnetic poles rotating centering around the shaft, and a circuit to short circuit the decelerating coil by induction, to thereby decelerate the motor.