MAGNETIC ENCODER AND METHOD FOR MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a magnetic encoder and a method for manufacturing thereof in which magnetic force stable region can be made wider by increasing an outer diameter of an annular plastic magnet.SOLUTION: An axial-type magnetic encoder 1 comprises: an annular fixing member 2 manufactured by press molding which consists of a cylindrical part 2A attached to a rotor and an inward flange part 2B extending from an edge of the cylindrical part 2A inside in a radial direction; and an annular plastic magnet 3 attached to a sensor facing surface of the annular fixing member 2 by injection molding, in which a surface (flat surface outer diameter FD) having high shape accuracy is formed on a sensor facing surface outside in the radial direction from a range of a diameter (d-2 r) which is obtained from an inner diameter d of the cylindrical part 2A and a radius r of a corner part between the cylindrical part 2A and the inward flange part 2B, and an outer diameter MD of the annular plastic magnet 3 is positioned on the surface having the high shape accuracy.