Patent ID: 6657349
Filing Date: 2003-12-02
Classification: H02K

Abstract:
An AC servo motor comprising:a stator-side iron core having a plurality of slots; and a rotor comprising an annular polar anisotropic magnet that is split into two or more annular polar anisotropic magnets in an axial line direction thereof, wherein a cogging torque is minimized by determining a number of torque ripples per rotation of the rotor based on the number of magnetic poles of the annular polar anisotropic magnet and a number of slots in the stator-side iron core, calculating a skew angle &thgr;â€² based on the number of torque ripples, determining an angle &thgr;â€² by adding skew angle &thgr; a value which accounts for magnetic interference occurring at the boundary between the split annular polar anisotropic magnets, and shifting the magnetic poles of the corresponding split annular polar anisotropic magnets by the predetermined angle &thgr;â€².