Method for magnetizing ring magnet and magnetic encoder

Abstract

An insert member (42) having an identical permeability is fitted in the circular center hole(41a) of a magnetic ring (41) which is then fitted in the circular hollow section (43a) of a fitting-over member (43) having an identical permeability. Under that state, the magnetic ring (41) is placed in a parallel magnetic field. Lines of magnetic flux passing through the magnetic ring (41) held between the insert member (42) and the fitting-over member (43) become linear without substantially inclining against the parallel magnetic field. Under that state, harmonic noise causing a deterioration in detection precision will scarcely appear in the output of a magnetic sensor for detecting the rotating magnetic field of a ring magnet (40) obtained by performing two-pole magnetization on the magnetic ring (41). When the ring magnet (40) is employed, a deterioration in the detection precision of a magnetic encoder (1) due to the magnetization state of the ring magnet (40) can be avoided, and the deterioration in detection precision can be suppressed.

Dependencies are inferred from the claim text.