Study on the Manufacturing Method of the Motor Cores to Reduce the Cogging Torque
| Autor: | Takashi Yoshioka, Takashi Miyoshi, Hiroyuki Akita, Yuji Nakahara |
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| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | Journal of the Japan Society for Precision Engineering. 73:711-716 |
| ISSN: | 1882-675X 0912-0289 |
| DOI: | 10.2493/jjspe.73.711 |
| Popis: | In recent years, to meet demands for high efficiency, the use of concentrated winding motors, in which the coil is wound around every magnetic pole tooth, has increased. By using a separate core structure, the coil fill factor of the motor, and the motor efficiency per unit volume, are improved. However, since the assembly error is large compared with non-separate cores, a separate core can produce an imbalance in the flux distribution during motor rotation and cause cogging torque to increase. Usually the core assembly precision is determined by the circularity of inner core, however, it is difficult to predict the cogging torque of a separate core from its circularity because the circularity does not correlate well with the cogging torque.So, in this paper, with reference to the inner core shape, one or several points of deformation were intentionally introduced and the relationship with cogging torque was investigated. Consequently, it became clear that cogging torque caused by the inner core shape is the main component of cogging torque. Moreover, it turned out that cogging torque when there were several points of deformation was the vector sum of the cogging torque resulting from each one. From these results, a new evaluation method which predicts the cogging torque more precisely than evaluation using the circularity of inner core has been established. Furthermore, a new core, which we call a “joint-lapped core” is proposed as a core structure which can reduce cogging torque. Because the joint-lapped core was made by a press, similar to a conventional cylindrical core, the circularity and the cogging torque of the joint-lapped core were the same grade as non-separate cores. |
| Databáze: | OpenAIRE |
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