The cogging torque of a spindle motor can be reduced by arcing the salient
poles of the stator or by modifying the magnetization profile of the rotor
magnet. By arcing the shape of the salient poles, the cogging torque can be
reduced to a specific amount. After the primary (elementary) salient pole
shape is determined, rotor magnets magnetized by different magnetization fi
xture shapes and magnetization current values are investigated with the goa
l of holding the torque constant of motors as well as reducing the cogging
torque. We have demonstrated that the cogging torque can be reduced to 4 g
cm without sacrificing the torque constant of the motor by properly reshapi
ng the magnetization fixture as well as reshaping the stator. (C) 2000 Else
vier Science B.V. All rights reserved.