Hybrid step motor

摘要

A stepper motor is provided in which a permanent ring magnet is sandwiched in an outer part of the stator winding assembly located far from the gap between rotor and stator teeth, so that magnetic flux in the gap is dominated by the Ampere-turns of energized stator coils and therefore more easily controlled for reduced vibration at low stepping speeds. The rotor need not contain any permanent disk magnet. If one is provided, it can be completely embedded within the rotor and merely supplement the primary flux from the stator to enhance torque. In most cases, where the rotor lacks any permanent magnet, the motor's axial shaft can have a larger diameter and may, together with the rotor, form a linear actuator.

主权项

1. A stepper motor, comprising:
a rotor with a plurality of rotor teeth, the rotor fitting within a stator winding assembly and seated by bearings on an axial shaft so as to rotate within the stator winding assembly; and the stator winding assembly including a stator with a set of stator poles wound with coils that can be driven in a series of phases so as to magnetically interact with the rotor, the stator poles having sets of stator teeth that are selectively magnetized by energizing of the stator coils, the stator characterized by having a permanent ring magnet sandwiched between outer portions of two stator stack elements of the stator outside of the coils, the permanent ring magnet having a ring interior with magnetic flux from the permanent ring magnet passing axially through the ring interior to remotely magnetize the rotor and its rotor teeth, such that magnetic flux in an air gap between rotor and stator teeth is dominated by the flux generated by Ampere-turns of energized stator coils with reduced flux interactions from non-energized poles.