Patent attributes
The magnetic encoder includes: a core member of annular shape having a press-fitting portion which bends and extends from an edge of a track formation surface, and to which a rotary shaft is press-fitted and fixed; and two or more rows of magnetic tracks arranged adjacent to each other on a magnetic member provided on the track formation surface, each track having N poles and S poles alternately magnetized thereon. The two or more rows of magnetic tracks include a main track that has a largest number of magnetic poles and is used for calculating an angle of rotation, and a sub track used for calculating a phase difference from the main track. The main track is located on a side more distant from the press-fitting portion than the sub track.