Patent ID: 6784661
Filing Date: 2004-08-31
Classification: G01D

Abstract:
A rotation detecting apparatus comprising:a drive gear supported rotatably by a case having a cover and capable of rotating cooperatively with an object to be detected; a driven gear brought in mesh with the drive gear and capable of rotating cooperatively therewith; a magnet provided at a rotational center portion of the driven gear and having an end face portion contiguously formed with an N pole and an S pole; a circuit board arranged at the case; and a magnetic reluctance element attached to the circuit board and being opposed to the end face portion of the magnet and an electronic circuit part for converting an output signal of the magnetic reluctance element into a rotational angle signal; wherein the driven gear is rotatably interposed by the case and the cover and a constant distance is maintained between the end face portion and the magnetic reluctance element.