Composite magnet stepper motor

Abstract

The stepper motor comprises a multi-pole composite magnet which functions as a rotor, two stator members which determine the angular position of this rotor, and means for positioning the rotor and the stator members on a common axis. The composite magnet comprises two sections, each section having a plurality of projections and apertures. The projections and apertures on a first section mate with the apertures and projections, respectively, on the second section. The first and second sections are magnetized in opposite axial directions. Each stator member has a plurality of pole pieces which are positioned in operative relation to the composite magnet. In one embodiment, two windings are formed on each stator member. Applying current to one or both of these determines the polarity of the pole pieces on that stator member. In another embodiment, a stator member comprises a hollow, toroid-shaped trough. Pole fingers extend from the edges opposite the edges defining the bottom of the trough. Two windings are placed in the trough and the pole fringes are then bent to secure these windings and complete the electromagnetic circuit.