| 摘要 |
PURPOSE:To reduce the duty error of ON/OFF by forming a magnetic ring at opposite side to the sensor magnet of a Hall element, thereby raising the sensitivity of the element. CONSTITUTION:A sensor magnet 12 is retained by an anti-rotation ring 13 at the end 5a of a rotor 5 projected from a bracket 10a. A holder 15 for securing a sensor P plate 14 is mounted at the bracket 10a, and a plurality of Hall elements 16 are secured to the holder. A ring 17 of magnetic material is inserted into the holder 15 to enclose the periphery of the elements 16. With this construction, wide Hall elements can be selected to reduce the number of steps and cost of selectively using the Hall elements. |
