Electrified vehicle having electric machine stator with slot pocket
A vehicle, electric machine, and stator include stator teeth extending from a yoke portion toward a rotor and defining slots between adjacent teeth with windings positioned within the slots, wherein the teeth form pockets at connections to the yoke portion. Electrically insulating slot paper may line at least three sides of the slots. The pockets may extend into the teeth or the yoke portion where the teeth extend from the yoke portion, and may be filled with an electrically insulating compound that secures the insulating slot paper lining and electrically conductive rectangular windings within the slots.
1. A vehicle comprising:
a traction battery; and
an electric machine powered by the traction battery and configured to provide propulsive power to the vehicle, the electric machine including a rotor separated by an air gap from a stator surrounding the rotor, the stator including teeth extending from a yoke portion toward the rotor and defining slots between adjacent teeth with windings positioned within the slots, wherein the teeth or the yoke portion define pockets in the slots, wherein the stator teeth form rectangular slots having parallel sides extending from the pockets toward the air gap, wherein the slots include an insulating slot liner disposed between the windings and at least three sides of each of the slots, and wherein the pockets are filled with an electrically insulating compound between the insulating slot liner and the teeth or the yoke portion.
2. The vehicle of claim 1 wherein the stator teeth form rounded pockets at the connections to the yoke portion.
3. The vehicle of claim 2 wherein the stator teeth form rectangular slots having parallel sides extending from the pockets toward the air gap.
4. The vehicle of claim 2 wherein the pockets extend radially into the yoke portion.
5. The vehicle of claim 2 wherein the pockets extend into a side of an associated tooth.
6. The vehicle of claim 2 wherein the pockets extend diagonally from an associated slot into both a sidewall of an associated tooth and the yoke portion.
7. The vehicle of claim 1 wherein each pocket connects to a side of an associated tooth at a distance from the yoke portion of less than one-half a radial thickness of one conductor of the windings.
8. An electric machine comprising:
a rotor; and
a stator surrounding the rotor and separated by an air gap, the stator comprising teeth extending from a yoke portion toward the rotor and defining rectangular slots with electrically insulating slot paper lining at least three sides of the rectangular slots, wherein the slots include rounded pockets extending into the teeth or the yoke portion where the teeth extend from the yoke portion, and wherein the pockets are filled with an electrically insulating compound that secures the insulating slot paper lining and electrically conductive rectangular windings within the rectangular slots.
9. The electric machine of claim 8 wherein the rounded pockets extend from the yoke portion a radial distance less than half the radial width of a single conductor of the rectangular windings.
10. The electric machine of claim 8 wherein the rounded pockets defined by the stator teeth have an apex disposed diagonally from an associated slot into both the teeth and the yoke portion.
11. The electric machine of claim 8 wherein the stator comprises a plurality of stacked laminations.
12. An electric machine stator comprising:
a yoke portion; and
teeth integrally formed of unitary construction with the yoke portion and extending from the yoke portion toward an inner circumference to form concave fillets between the teeth and the yoke portion, adjacent teeth forming a slot therebetween containing an insulating slot liner and windings, the concave fillets containing an electrically insulating fluid between the slot liner and the yoke-portion.
13. The electric machine stator of claim 12 wherein the teeth form concave fillets with the yoke portion.
14. The electric machine stator of claim 13 wherein the concave fillets extend into both the yoke portion and sides of the teeth.
15. The electric machine stator of claim 12 wherein the concave fillets extend into sides of the teeth but not the yoke portion.
16. The electric machine stator of claim 12 wherein the concave fillets extend into the yoke portion without extending into sides of the teeth.
17. The electric machine stator of claim 12 wherein the teeth form rectangular slots and wherein the concave fillets extend less than half the radial width of a single rectangular conductor of the windings within the rectangular slots from the yoke portion.