| 摘要 |
<p>The magnetic sensing system consists of three Hall effect or magnetic resistivity elements (1) on a common substrate (4) mounted in an arc near the circumference of the rotating automobile part (2). Each element also has a permanent magnet to provide an ambient magnetic field level and two out pole pieces (6). The rotating part has a number of equi-spaced teeth (3), which pass the pole pieces (6) of the elements, leaving only a small air gap (7). The radial angle between adjacent sensing elements (1) is equal to one-third of that between the teeth on the rotating part. The outputs of the elements are fed to an electronic circuit which analyses the timing of changes of flux levels at the three elements to determine the direction of rotation of the part (2).</p> |
