MAGNETIC ENCODER AND MANUFACTURING METHOD THEREOF

摘要

Provided is a magnetic encoder in which the outer diameter of an annular plastic magnet is increased to widen a magnetic force stable region, and a manufacturing method thereof. An axial-type magnetic encoder 1 includes: an annular fixing member 2 that has a cylindrical part 2A attached to a rotating body and an inward flange part 2B extended radially inward from an end edge of the cylindrical part 2A and is fabricated by press molding; and an annular plastic magnet 3 that is attached by injection molding to a sensor-opposed surface of the annular fixing member 2. The magnetic encoder 1 has a high-form accuracy surface (outer diameter FD of a flat surface) on the sensor-opposed surface more radially outward than a range of a diameter (d−2·r) determined by an inner diameter d of the cylindrical part 2A and a radius r of a corner between the cylindrical part 2A and the inward flange part 2B. An outer diameter MD of the annular plastic magnet 3 is positioned on the high-form accuracy surface.

主权项

1. An axial-type magnetic encoder, comprising:
an annular fixing member that has a cylindrical part attached to a rotating body and an inward flange part extended more radially inward than an end edge of the cylindrical part and is fabricated by press molding; and an annular plastic magnet that is attached by injection molding to a sensor-opposed surface of the annular fixing member, wherein when the annular fixing member is composed of a cylindrical part and an inward flange part extended radially inward from an end edge of the cylindrical part, the magnetic encoder has a high-form accuracy surface on the sensor-opposed surface more radially outward than a range of a diameter (d−2·r) determined by an inner diameter (d) of the cylindrical part and a radius (r) of a corner between the cylindrical part and the inward flange part, and an outer diameter of the annular plastic magnet is positioned on the high-form accuracy surface.