Mohawk Innovative Technology, Inc.

H Ming Chen

Hooshang Heshmat

James F Walton, Ii

Dennis H Locke

A method for bearing a rotor in which load is shared between a foil bearing part and a magnetic bearing part without using a calculated rotor trajectory corresponding to various rotor spin speeds. Power input to the magnetic bearing part is controlled in response to feedback of rotor position. In order to share the load on the fly so that the load is shared quickly as the rotor speed is changed, the power input is modified in response to rotor spin speed to reduce load capacity of the magnetic bearing part as rotor spin speed is increased and increase load capacity of the magnetic bearing part as rotor spin speed is decreased. Alternative methods of modifying power input include modifying integral gain and inputting rotor spin speed to an adaptive filter to continually reset the adaptive filter at the rotor spin speed. For use of the process with a thrust bearing, the magnetic and foil bearing parts are disposed on opposite sides of the thrust runner.

Hybrid foil-magnetic bearing

In order to provide a blood pump bearing having a suitable stiffness, magnetic rings for a journal bearing are provided on each of the stationary portion and the rotor and disposed in magnetically interacting facing relationship on opposite sides of a gap, and a thrust bearing is provided on the stationary portion and the rotor and disposed with magnets in magnetically interacting facing relationship on opposite sides of the same or another gap. The pump motor preferably has a bearing span which is at least about 2&frac12; times greater than an average radius of the distributed magnetic force. In accordance with one embodiment, the stator has at least one axial extension, an axially extending gap is provided between the stator and rotor, and a journal bearing has magnets interactively disposed on opposite sides of the gap. In accordance with another embodiment, at least one pair of permanent magnets on the housing are movable relative to at least one pair of permanent magnets on the rotor which are oriented in an attractive relationship thereto in response to axial displacement of the rotor.

Pump having magnetic bearing for pumping blood and the like

A magnetic bearing wherein a stator is magnetically interacted with a rotor and is movable in response to feed-back of rotor position to thereby use the magnetic interaction between the stator and rotor to effect movement of the rotor toward a predetermined rotor position for bearingly controlling the rotor position. The bearing may be a radial or thrust bearing.

Stator-controlled magnetic bearing

An auxiliary bearing for temporarily receiving rotor load when the main bearings are unable to receive rotor load. A plurality of rollers or sets of rollers are spaced circumferentially around the rotor. At least some of the rollers are movable between first radial positions which afford clearance between the rollers and the rotor and second radial positions for receiving by the rollers of rotor load. The movement of one roller toward the second radial position in response to contact therewith by the rotor effects movement of all of the at least some rollers toward the second radial positions to close the clearance and receive the rotor load. The rollers then disengage when the rotor load is again taken by the main bearings.

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Latham, NY, United States of America

H Ming Chen