Stepping motor rotor assembly body null of electronic

摘要

PURPOSE: To reduce cost while preventing damage by a structure wherein a washer group holds a permanent magnet at a fixed position of a rotor and the tubular wall part at a recessed part locates the permanent magnet in the center with respect to a drive shaft. CONSTITUTION: A rotor comprises a drive member 6 having a gear meshed with the gear train of a clock and a drive shaft 4 and axial movement of a centering washer 12 on the drive shaft 4 is regulated by a regulating means. A washer 16 group holds a permanent magnet at a fixed position of the rotor and the tubular wall part 24 at a recessed part locates the permanent magnet 14 in the center with respect to the drive shaft 4. When a rotor magnet is formed, central hole thereof is bore directly and rough drilling is performed by means of a planetary laser beam. Since press-fitting of magnet is not required, cost can be reduced while preventing damage.