Citizen Watch Company, Ltd.

Citizen Holdings Company, Ltd.

Yousuke Sakakibara

Hiroshi Ikeda

Junji Sato

Eigo Hashimoto

Hideharu Miyauchi

Eikichi Sashida

A rotor ( ) for a miniature electric motor includes a magnet ( ) having a rotation axis ( ) and a shaft ( ) fixed concentrically to the magnet. The magnet ( ) includes a through hole ( ) extending coaxially with the rotation axis ( ). The shaft ( ) includes a portion ( ) fitted in the through hole ( ). The portion ( ) has an axial interengagement length (t ) shorter than an axial length (T ) of the through hole ( ). The rotor ( ) also includes reinforcing means provided at least inside the through hole ( ). The magnet ( ) comprises an annular magnet material ( ), and a coating ( ) formed on a surface of the magnet material and arranged at least inside the through hole ( ). The reinforcing means is formed as the coating ( ) of the magnet ( ), and acts to ensure a fixing force to securely hold the shaft ( ) in a predetermined position on the magnet.

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Tokorozawa, Japan

Yousuke Sakakibara