Performance improvement of spoke-shaped interior permanent magnet magnetic gear

Y. Mizuana, K. Nakamura, Y. Suzuki, Y. Oishi, Y. Tachiya, K. Kuritan

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Magnetic gears have several advantages such as having low acoustic noise and being maintenance-free because there is no mechanical contact. Among these gears, the flux-modulated type has a higher torque density and efficiency than the other types. Therefore, it is expected to be put into practical use. In previous papers, a spoke-shaped interior permanent magnet (IPM) rotor structure was proposed in order to reduce the eddy current loss in magnets. This paper presents three methods for improving the performance of the spoke-shaped IPM magnetic gear. First, the position of the magnetic bridges is changed from the air gap side to the back yoke side to increase the effective magnetic flux. Second, amorphous alloy is used for the rotor core and pole pieces in order to reduce iron loss. Third, bonded Nd-Fe-B magnets for canceling the leakage flux are arranged to sandwich the inner rotor from both sides. As a result of prototype tests, the measured maximum torque of the proposed spoke-shaped IPM magnetic gear was 44% higher than that of the conventional one. In addition, the measured maximum efficiency reached 99.85% at 100 rpm.

Original languageEnglish
Pages (from-to)50-55
Number of pages6
JournalJournal of the Magnetics Society of Japan
Issue number3
Publication statusPublished - 2021


  • Amorphous alloy
  • Cancel magnet
  • Interior permanent magnet (IPM)
  • Magnetic bridge
  • Magnetic gear


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