Stepper motor with integrated assembly

A stepper motor including a stator having a central axis and at least one winding disposed about the axis for producing a plurality of magnetic poles in the stator, a permanent-magnet rotor having a plurality of magnetic poles and being mounted for rotation about the axis, a housing disposed around the stator, and a shaft coupled to the rotor such that rotation of the rotor effects linear motion of the shaft, characterized in that:

• a. the shaft extends axially out of an opening in a tubular end of the stator and includes first and second ends, said first end being coupled to the rotor;
• b. an operative member is attached to the second end of the shaft;
• c. the tubular end of the stator has an outer surface of predefined cross-sectional shape:
• and
• d. a tubular member having said predefined cross-sectional shape extends axially from the operative member and around the tubular portion of the stator, said tubular member, said tubular end of the stator, and said opening in the tubular end defining a labyrinthal path that inhibits the passage of contaminants from outside of the motor into the rotor.