Lubricant supported electric motor including magnetic rotor centering
A lubricant supported electric motor including a stator presenting a stator raceway, and a rotor extending along an axis and rotatable relative to the stator. The rotor presents a rotor raceway disposed in spaced relationship with the stator raceway to define a gap there between. A lubricant is disposed in the gap for supporting the rotor relative to the stator. The rotor includes a plurality of rotor poles arranged adjacent the rotor raceway in circumferentially spaced relationship with one another, and the stator includes a plurality of stator poles extending radially towards the rotor in circumferentially spaced relationship with one another along the stator raceway. A plurality of stator coil windings are wrapped around the plurality of stator poles and individually controllable for generating a magnetic force to center the rotor within the stator with carefully-timed adjustments to magnetic fields generated by the stator.
1. A lubricant supported electric motor comprising:
a stator presenting a stator raceway;
a rotor extending along an axis and rotatable relative to said stator and presenting a rotor raceway disposed in spaced relationship with said stator raceway to define a gap therebetween;
a lubricant disposed in said gap for supporting said rotor within said stator;
said rotor including a plurality of rotor poles arranged adjacent said rotor raceway in circumferentially spaced relationship with one another;
said stator including a plurality of stator poles extending radially towards said rotor in circumferentially spaced relationship with one another along said stator raceway; and
a plurality of stator coil windings each distinctly wrapped around a respective one of said plurality of stator poles and individually controllable for generating a magnetic force to center said rotor relative to said stator; and
a plurality of power transistors each individually disposed in electrical communication with a respective one of said plurality of stator windings and configured to individually drive current through said respective one of said plurality of stator windings to effectuate said individualized control of each one of said plurality of stator coil windings.
2. The lubricant supported electric motor as set forth in claim 1 , wherein said plurality of rotor poles includes at least one set of diametrically opposed rotor north poles and at least one set of diametrically opposed rotor south poles disposed in circumferentially staggered relationship to one another and said plurality of stator poles includes at least one pair of diametrically opposed stator poles, and wherein said stator coil windings wrapped around each of said diametrically opposed stator poles are configured to generate a repelling magnetic force in response to at least one of said sets of diametrically opposed rotor north or south poles being disposed adjacent and radially aligned with said at least one pair of diametrically opposed stator poles.
3. The lubricant supported electric motor as set forth in claim 2 wherein said stator coil windings wrapped around each of said diametrically opposed stator poles are biased to create magnetic north stator poles in response to said at least one of said set of diametrically opposed rotor north poles being disposed adjacent and radially aligned with said at least one pair of diametrically opposed stator poles for magnetically centering said rotor within said stator.
4. The lubricant supported electric motor as set forth in claim 2 wherein said stator coil winding wrapped around each of said diametrically opposed stator poles are biased to create magnetic south stator poles in response to said at least one of said set of diametrically opposed rotor south poles being disposed adjacent and radially aligned with said at least one pair of diametrically opposed stator poles for magnetically centering said rotor within said stator.
5. The lubricant supported electric motor as set forth in claim 2 , wherein said plurality of power transistors are configured to individually drive current through said at least one set of diametrically opposed stator poles for alternating said at least one set of diametrically opposed stator poles between a north stator pole and a south stator pole arrangement.
6. The lubricant supported electric motor as set forth in claim 5 , further comprising a controller disposed in electrical communication with said plurality of power transistors and configured to operate said plurality of power transistors based on a condition of the lubricant supported electric motor.
7. The lubricant supported electric motor as set forth in claim 6 , wherein said at least one set of diametrically opposed stator poles are radially aligned with a gravitational force acting on the lubricant supported electric motor, and said controller is configured to operate said plurality of power transistors during an “un-park” initialization of the lubricant supported electric motor for lifting said rotor and magnetically centering said rotor within said stator.
8. The lubricant supported electric motor as set forth in claim 5 , wherein said plurality of power transistors are connected to a DC bus and arranged adjacent said plurality of stator coils.
9. The lubricant supported electric motor as set forth in claim 1 , wherein said rotor is operably connected to a final drive device that is interconnected to a wheel of a vehicle.
10. The lubricant supported electric motor as set forth in claim 1 , wherein said rotor is rotatably disposed within said stator.