Stepper motor with integrated assembly

摘要

A stepper motor of the permanent-magnet sheet-metal type is constructed of a number of modules, simplifying assembly. The modular parts include a stator having integrally-molded winding bobbins and pole pieces. A rotor mounted in the stator includes a barrier member which separates a plastic, threaded hub molded interiorly from a permanent magnet molded exteriorly. A shaft having a first threaded end rotatably engaged with the interior of the rotor hub has a rectangular central portion extending through a rectangular opening of the stator to convert rotary motion of the rotor to linear motion of the shaft. An opposite end of the shaft includes a molded head and a tubular shield extending from the head. This shield and a tubular portion of the stator molding define a labyrinthal passage which inhibits the passage of contaminants into the rotor. A housing of the motor and a rotatably attached flange include engagable portions to lock the flange at a desired angular position.