| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a less expensive rotational speed detection mechanism that eliminates a risk of directly damaging a magnetic detection element, increases a density of flux passing through the magnetic detection element, and improves a precision of a detection signal of a rotation speed. <P>SOLUTION: The rotational speed detection mechanism includes a multipole magnet encoder 1 and a magnetic sensor 2. The magnetic sensor 2 includes a first and a second yokes 10A, 10B formed respectively with a magnetic path having a cross section gradually reducing from one end to the other end, a magnetic detection element 3, and a resin body 4 holding the yokes 10A, 10B and the magnetic detection element 3. In the first and the second yokes 10A, 10B, end surfaces 13 on the one end are opposed to a surface of a multipole magnet encoder to be detected. A distance between the end surfaces 13 on the one end are determined to correspond to an array pitch between an N pole and an S pole of the surface of the multipole magnetic encoder to be detected. End surfaces 14 on the other end are opposed to each other via a gap therebetween. The magnetic detection element 3 is arranged in the gap between the end surfaces 14 on the other end of the two yokes 10A, 10B. <P>COPYRIGHT: (C)2012,JPO&INPIT |
