| 摘要 |
A motion sensor for detecting and providing an indication of the direction of motion along a predetermined line of travel of a smooth, uninterrupted, generally flat or gently curved, ferromagnetic target surface of a movable member includes a permanent magnet, at least one active field sensor for sensing magnetic field intensity and mounting structure for positioning the magnet and sensor along the line of travel in fixed spatial relationship to the target surface and to each other. The magnetic field of the permanent magnet, upon movement of the target surface relative to the permanent magnet along the line of travel, creates asymmetric magnetic fields along the target surface on either side of the axis which are unequal in strength in a way which is dependent upon the relative direction of motion of the target surface. The sensed magnetic intensity permits determination of the direction of motion, where the target surface is ferromagnetic, and velocity, where the target surface is conductive.
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