| 摘要 |
<p>PURPOSE:To enable an output of a sensor 16 for detecting rotary speed to be fully large without using a permanent magnet 19 with specifically large magnetic force. CONSTITUTION:A sensor 16 is provided with a pole piece 17 where a coil 18 Is wound and a permanent magnet 19. The other edge of a back yoke 21 whose one edge is in contact with an end face of the permanent magnet 19 at the opposite side of the pole piece 17 is brought closer to an end face of a hub 1, thus enabling a magnetic resistance to be reduced and an electromotive force which is induced at the coil 18 to be increased.</p> |
