| 摘要 |
<p>A shaft 102 is constrained such that as it rotates it moves axially. A magnet 101 is mounted at the end of the shaft 102, the magnet having its magnetic axis substantially perpendicular to and intersecting with the rotational axis of said shaft 102. A monitoring device 107 is mounted adjacent to the end of the shaft. The monitoring device is provided for monitoring the position of the shaft 102 as it is rotated through angles greater than 360 degrees. The monitoring device comprises a pair of Hall elements operable to generate electrical signals in response to a local magnetic field component in the plane of the surface of the integrated circuit, said pair of Hall elements being aligned perpendicular to each other. As shaft 102 rotates the magnet 101 also rotates relative to the Hall elements in the monitoring device 107 and hence the angular position of the shaft 102 relative to the monitoring device may be determined. As axial motion occurs when shaft 102 rotates, the distance between the magnet 101 and the monitoring device 107 varies. As a result, by monitoring the overall magnitude of the local magnetic field at monitoring device 107 the axial position of shaft 102 can also be determined.</p> |
