| 摘要 |
PURPOSE:To reduce the size of a motor by providing a frequency generator FG magnet multipolarly magnetized in the end direction at a rotor yoke, and oppositely arranging the magnet and an FG pattern through an axial air gap at a stator side. CONSTITUTION:An FG magnet 9 is provided at the rotor side of a motor and, an FG pattern 10 is provided through an axial air gap 12 at the stator side of the motor. the magnet 9 is multipolarly magnetized in the end direction. The pattern 10 is composed at the conductor connection 10a at the same pole pitch P as the magnet 9, a voltage is induced by the relative rotation to the magnet 9 at every conductor, a frequency output voltage V proportional to the rotating speed applied in phase is produced from the output terminal of the pattern 10, and the output voltage is fed back as a speed signal to control the speed of a DC motor. Thus, the thickness of the axial air gap can be shortenend, thereby reducing the size of the motor. |
