MOTOR WITH SPEED DETECTOR

摘要

PURPOSE:To reduce the influence of a leakage magnetic field from a rotor magnet by fixing a magnetic recording medium through a nonmagnetic material at the middle to a support which is integrally installed at a rotary yoke. CONSTITUTION:A magnetic recording medium 15' is fixed through a nonmagnetic material 12 at the middle to a magnetic recording medium support 8 provided integrally with a rotor yoke 7. Since the material 12 is disposed at the middle, magnetic flux which flows from N-pole through the yoke 7 to the S-pole can be largely reduced to a plurality of N-poles and S-poles magnetized and recorded on the medium 15' as compared with the structure that the medium 15' is bonded to the yoke 7, with the result that a magnetic field to be applied to the magnetic reluctance effect element 10' can be strengthened.