Electric motor with airgap and stator slot cooling
An electric motor includes a stator having windings disposed within winding slots. The stator includes a radially inner stator core surface, a radially outer stator surface, and at least one stator passage extending radially a first distance from the inner stator core surface. A rotor is mounted inside the stator and includes at least one fluid passage extending radially through the rotor to the radially outer rotor surface. A fluid circulation arrangement is configured to receive a first liquid via a first passage and a gas via at least one second passage, and direct the first liquid and the gas, via centrifugal force, into the airgap and the at least one stator passage as the rotor rotates inside the stator to discharge the first liquid and the gas out through the airgap and the at least one stator passage radially, and through the windings axially, thereby cooling the electric motor.
1 . An electric motor comprising:
a stator including windings disposed within winding slots, the stator having a radially inner stator core surface and a radially outer stator surface, wherein the stator includes at least one stator passage extending radially a first distance from the radially inner stator core surface;
a rotor mounted inside the stator, defining a rotational axis, and having axially opposite rotor ends and a radially outer rotor surface positioned proximate the radially inner core stator surface, thereby establishing an airgap therebetween, wherein the rotor includes at least one fluid passage extending radially through the rotor to the radially outer rotor surface; and
a fluid circulation arrangement configured to receive a first liquid via a first passage and a gas via at least one second passage, and direct the first liquid and the gas, via centrifugal force, into the airgap and the at least one stator passage as the rotor rotates inside the stator to discharge the first liquid and the gas out through the airgap and the at least one stator passage radially, and through the windings axially, thereby cooling the electric motor.
2 . The electric motor as recited in claim 1 , wherein the at least one stator passage extends a second distance from the radially inner stator core surface to an opening in the radially outer stator surface, the second distance greater than the first distance and the at least one second passage entirely surrounds a portion of the first passage, and a longitudinal axis of each of the first passage and the at least one second passage is aligned with the rotational axis of the rotor.
3 . The electric motor as recited in claim 2 , wherein the fluid circulation arrangement is configured to receive a second liquid through the opening in the radially outer stator surface via the at least one stator passage.
4 . The electric motor as recited in claim 3 , wherein the fluid circulation arrangement further includes a rotor shaft positioned coaxially with the rotor, fixed to the rotor, and defining the first passage.
5 . The electric motor as recited in claim 4 , wherein the rotor shaft defines the at least one second passage.
6 . The electric motor as recited in claim 1 , wherein the stator further includes stator teeth that extend radially from the radially inner stator core surface and alternate with the winding slots circumferentially along a channel portion of the stator, and wherein the stator teeth within the stator passage have a tapered configuration and a slot liner in each of the winding slots surrounding a corresponding set of windings and the slot liner defines at least one aperture along a radially inner or a radially outer edge of the slot liner.
7 . The electric motor as recited in claim 6 , wherein the stator teeth within the stator passage are narrower than the stator teeth not within the stator passage.
8 . The electric motor as recited in claim 1 , wherein the stator further includes stator teeth that extend radially from the radially inner stator core surface and alternate with the winding slots circumferentially along a channel portion of the stator, and wherein the stator teeth within the stator passage are removed.
9 . An electric motor comprising:
a stator including windings disposed within winding slots, the stator having a radially inner stator core surface and a radially outer stator surface, wherein the stator includes at least one stator passage extending radially a first distance from the radially inner stator core surface;
a rotor mounted inside the stator, defining a rotational axis, and having axially opposite rotor ends and a radially outer rotor surface positioned proximate the radially inner stator core surface, thereby establishing an airgap therebetween, wherein the rotor includes at least one fluid passage extending radially through the rotor to the radially outer rotor surface; and
a fluid circulation arrangement configured to receive a first liquid via a first passage and a gas via at least one second passage, and direct the first liquid and the gas, via centrifugal force, into the airgap and the at least one stator passage as the rotor rotates inside the stator to discharge the first liquid and the gas out through the airgap and the at least one stator passage radially, and through the windings axially, thereby cooling the electric motor;
wherein the fluid circulation arrangement further includes a rotor impeller defining a plurality of fluid channels, and wherein the radially outer rotor surface defines circumferentially distributed apertures fluidly connected to a respective plurality of fluid channels;
the rotor impeller is arranged along the rotational axis centrally within the rotor;
the rotor has a three-piece structure, including a first lateral rotor portion and a second lateral rotor portion, wherein the rotor impeller is disposed adjacent to both the first lateral rotor portion and the second lateral rotor portion.
10 . The electric motor of claim 9 , wherein the at least one second passage entirely surrounds a portion of the first passage, and a longitudinal axis of each of the first passage and the at least one second passage is aligned with the rotational axis of the rotor.
11 . The electric motor as recited in claim 9 , wherein the at least one stator passage extends a second distance from the radially inner stator core surface to an opening in the radially outer stator surface, the second distance greater than the first distance.
12 . The electric motor as recited in claim 11 , wherein the fluid circulation arrangement is configured to receive a second liquid through the opening in the radially outer stator surface via the at least one stator passage.
13 . The electric motor as recited in claim 12 , wherein the fluid circulation arrangement further includes a rotor shaft positioned coaxially with the rotor, and the rotor shaft is fixed to the rotor with the rotor shaft defining the first passage and the at least one second passage.
14 . A motor vehicle comprising:
an electric motor configured to generate torque for propulsion of the motor vehicle, the electric motor including:
a stator including windings disposed within winding slots, the stator having a radially inner stator core surface and a radially outer stator surface, wherein the stator includes at least one stator passage extending radially a first distance from the radially inner stator core surface;
a rotor mounted inside the stator, defining a rotational axis, and having axially opposite rotor ends and a radially outer rotor surface positioned proximate the radially inner stator core surface, thereby establishing an airgap therebetween, wherein the rotor includes at least one fluid passage extending radially through the rotor to the radially outer rotor surface; and
a fluid circulation arrangement configured to receive a first liquid via a first passage and a gas via at least one second passage, and direct at least one of the first liquid and the gas, via centrifugal force, into the airgap as the rotor rotates inside the stator to discharge the first liquid and the gas out through the airgap, and through the windings axially, thereby cooling the electric motor.
15 . The motor vehicle of claim 14 , wherein the fluid circulation arrangement is configured to direct the first liquid and the gas, via centrifugal force, into the airgap as the rotor rotates inside the stator to discharge the first liquid and the gas out through the airgap and the at least one stator passage radially.
16 . The motor vehicle as recited in claim 15 , wherein the at least one stator passage extends a second distance from the radially inner stator core surface to an opening in the radially outer stator surface, the second distance greater than the first distance.
17 . The motor vehicle as recited in claim 16 , wherein the fluid circulation arrangement is configured to receive a second liquid through the opening in the radially outer stator surface via the at least one stator passage and the fluid circulation arrangement further includes a rotor shaft positioned coaxially with the rotor, fixed to the rotor, and defining the first passage.
18 . The motor vehicle as recited in claim 17 , wherein the rotor shaft defines the at least one second passage.
19 . The motor vehicle as recited in claim 16 , wherein the first passage includes the stator passage, the rotor defines the at least one second passage.
20 . The motor vehicle as recited in claim 16 , wherein the first passage includes the stator passage, and the at least one second passage is disposed between the rotor, and a rotor shaft positioned coaxially with the rotor, and the rotor shaft is fixed to the rotor.