| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a position detecting device capable of detecting the position of a moving member with greater accuracy. <P>SOLUTION: A rotation sensor 15 includes: a magnet 21 in which N pole magnets 21a and S pole magnets 21b are alternately arranged in a ring shape and that rotates in association with rotation of a spool; and first and second Hall effect elements 20a and 20b that are arranged apart from the magnet 21 in the circumferential direction of the magnet 21 and detects the magnetic poles of the N pole magnet 21a and S pole magnet 21b. In this case, both the first and second Hall effect elements 20a and 20b are unipolar-detecting Hall effect elements that detect only the S poles. The magnetization width of the S pole magnet 21b is set larger, while the magnetization width of the N pole magnet 21a is set smaller. <P>COPYRIGHT: (C)2012,JPO&INPIT |
