Electric motor with magnetic enhancement
AssigneeSigma Instruments, Inc.
InventorJohn G. Gamble
Life of this patent
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Abstract
Iron surfaces of stator poles, rotor periphery, or both stator poles and rotor periphery, of stepping motors are manufactured without teeth. The stepping effects of teeth are obtained by bonding, to the toothless surfaces, webs composed of fluted magnetic material having alternate thin and thick sections magnetized in the direction of the thickness of the material and carrying soft magnetic inserts in the flutes. The inserts form virtual teeth. The thick sections are magnetized in the direction opposite to the thin section and the flutes extend in the direction transverse to the direction of relative motion between rotor and stator.
Claims12
An electric motor, comprising:
- a stator having a plurality of poles;
- a winding on each of said poles;
- a mover movable relative to said stator poles;
- tooth forming means mounted on said stator pole and facing said mover;
- said tooth forming means including a permanent magnetic structure having a plurality of thin portions bonded to said stator poles and a plurality of thicker portions integral with said thin portions and bonded to said stator poles;
- said thin portions and said thicker portions being elongated and extending longitudinally in a direction transverse to movement of the mover relative to said stator and forming flutings between said thicker portions, said thicker portions projecting toward said mover;
- said thin and thicker portions being magnetized in directions toward and away from the mover, said thin portions and said thick portions being magnetized in opposite directions;
- a plurality of rods each fitted in the flutings and bonded to said tooth forming means, said rods being of a high permeability ferromagnetic material and forming teeth for said stator poles.
Dependencies are inferred from the claim text.