In recent years, the technology which heightens the output per unit volume by equipping a stator with a high-density coil using divided cores is used widely in order to improve the motor output or the motor efficiency. Since the divided cores really tend to generate work errors compared with the non-divided core, magnetic energy changes by few work errors, and there is a problem that the cogging torque known as torque ripple becomes large. Therefore, in the motor which has divided cores, it is useful industrially to obtain the manufacturing method which reduces cogging torque effectively by simple process.
In this research, by using the concentrated magnetomotive force model, the technique of writing the cogging torque resulting from the error of the inside diameter form of a stator as a vector was introduced, and the validity was verified. The rotary lamination method was proposed as a method of reducing cogging torque by making each other offsetting combining two or more torque vectors, and the effect was verified by experiment. In the experiment, the rotary lamination is realized by the manufacturing method with the divided cores which are pierced in the circular shape by a metallic mold. There will be room to study offsetting the torque vector of other factors by control the torque vector arbitrarily using the rotary lamination method of the divided cores.
