High-speed, low-loss antifriction bearing assembly
AssigneeThe Charles Stark Draper Laboratory, Inc.
InventorHerbert Malsky
Life of this patent
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Abstract
Antifriction bearings include circumferential as well as axial flux paths that the flux of four identical-polarity magnetic poles follows about an annular stator having annular end-pieces that enables a square law reduction in rotor eddy current effects over the heretofore known magnetic bearings. In one embodiment, control coils alone provide magnetic suspension along orthogonal X, Y axes, and in another embodiment, combination control and bias coils cooperate to provide magnetic suspension along the orthogonal X, Y axes. The stator and rotor are preferably constituted, in part, of a lamination of high magnetic permeability material.
Claims15
A high-speed low-loss antifriction bearing assembly, comprising:
- an elongated stator having an inside circumferential wall and defining first and second opposing ends;
- an elongated member to be magnetically suspended concentrically disposed for rotation within the stator;
- four elongated pole pieces disposed about the inside circumferential wall of the stator in equal angular increments of ninety degrees such that opposing pairs of the four elongated pole pieces define orthogonal X, Y, axes and in such a way that each pole piece of the opposing pairs of pole pieces defines with respect to the elongated member a preselected, comparatively-high magnetic reluctance;
- first and second annular end-pieces respectively disposed at said first and second opposing ends of said elongated stator in such a way that each annular end-piece defines with respect to the elongated member a preselected, comparatively-low magnetic reluctance;
- and
- coils wrapped about said pole pieces to provide magnetic fields of predetermined polarity that act to magnetically suspend said elongated member about said orthogonal X, Y axes.
A high-speed low-loss antifriction bearing assembly, comprising:
- a rotor;
- an elongated stator having four identical-polarity magnetic poles radially depending from a central, circumferential portion of the stator and two annular end-pieces one to each side of the stator, the poles having a preselected area and preselected pole-to-rotor gap that are selected to provide a comparatively-high reluctance and the end-pieces have a preselected area and end-piece-to-rotor gap selected to provide a comparatively-low reluctance between individual annular end-pieces and the rotor, each magnetic pole producing flux that flows along a flux path that includes a circumferential component that extends around the central circumferential portion of the stator and through the other three poles and across the associated comparatively-high reluctance between the poles and the rotor and an axial component that extends from each pole in both directions along the elongated stator and through respective annular end-pieces and across the associated comparatively-low reluctance gap.
Dependencies are inferred from the claim text.