| 摘要 |
PURPOSE:To obtain a rotor of a stable quality having a low inertia, by making a rotor seat, which is to be engaged with a rotor magnet, of a plastic, and fixing this rotor seat to a rotor wheel pinion by an ultrasonic fusing method. CONSTITUTION:A rotor seat 10 is made of a plastic material in the shape of a cup. A rotor magnet 9 is fixed to the inner surface of the cup-shaped rotor seat 10. The rotor seat 10 is provided in its bottom wall with an engagement bore at which the rotor seat 10 is to be fitted around a rotor wheel pinion 8. The shape of the engagement bore is identical with that of a cross section of the rotor wheel pinion 8. The rotor seat 10 is put on a rotor wheel pinion 8 such that the engagement bore provided in the former is fitted around teeth of the latter, and contact surfaces 11 thereof is fused. Thus, the rotor seat 10 is fixed to the rotor wheel pinion. |
