Method of making a rotating electric machine stator core
View Patent ↗A method of making a motor stator core having a back iron and a plurality of teeth extending radially inward from the back iron includes providing the plurality of teeth and the back iron from oriented steel so that a magnetic flux transmission path is formed with superior properties in essentially one direction. At least one of the plurality of teeth and the back iron is annealed in selected portions so as to improve magnetic flux transmission in a second direction, different from the one direction.
1. Method of making a rotating electric machine stator core having an annular back iron and a plurality teeth extending radially inward from the back iron, the method comprising:
providing the motor stator core made from an oriented steel that has superior magnetic properties which are aligned in essentially one direction; and
annealing selected portions of the oriented steel to remove the superior magnetic properties in the selected portions wherein, prior to annealing, said selected portions have the superior magnetic properties which are not substantially aligned with operational magnetic flux paths of the stator core.
2. The method as recited in claim 1 wherein annealing the selected portions of the oriented steel includes annealing only selected teeth wherein, prior to annealing, said selected teeth have the superior magnetic properties which are not substantially radially aligned.
3. The method as recited in claim 1 wherein providing the motor stator core comprises stacking a plurality of stator laminations made from the oriented steel, wherein each stator lamination comprises an annular lamination back iron and a plurality of lamination teeth extending radially inward from the annular lamination back iron and wherein annealing the selected portions of the oriented steel comprises:
annealing selected lamination teeth wherein, prior to annealing, said selected lamination teeth have the superior magnetic properties which are not substantially radially aligned; and
annealing selected portions of the annular back iron wherein, prior to annealing, said selected portions of the annular back iron have the superior magnetic properties which are not substantially annularly aligned.
4. The method as recited in claim 3 wherein stacking the plurality of stator laminations comprises angularly staggering the stator laminations.
5. The method as recited in claim 1 wherein annealing the selected portions of the oriented steel includes applying energy to the selected portions by using a rapidly changing magnetic field within the stator core similar to the operational magnetic flux paths of the stator core whereby greater heating of the selected portions of the oriented steel preferentially anneals the selected portions of the oriented steel over the non-selected portions of the oriented steel.
6. The method as recited in claim 1 wherein annealing the selected portions of the oriented steel includes applying heat to the selected portions of the oriented steel at a high temperature followed by cooling the selected portions of the oriented steel.
7. The method as recited in claim 1 wherein annealing the selected portions of the oriented steel includes applying heat to the selected portions of the oriented steel while simultaneously cooling non-selected portions of the oriented steel.
8. The method as recited in claim 1 wherein annealing the selected portions of the oriented steel includes annealing only selected portions of the annular back iron wherein, prior to annealing, said selected portions of the annular back iron have the superior magnetic properties which are not substantially annularly aligned.
9. The method as recited in claim 1 wherein annealing the selected portions of the oriented steel includes annealing selected portions of the annular back iron wherein, prior to annealing, said selected portions of the annular back iron have the superior magnetic properties which are not substantially annularly aligned, and annealing selected teeth wherein, prior to annealing, said selected teeth have the superior magnetic properties which are not substantially radially aligned.
10. The method as recited in claim 1 wherein providing the motor stator core comprises stacking a plurality of stator laminations made from the oriented steel, wherein each stator lamination comprises an annular lamination back iron and a plurality of lamination teeth extending radially inward from the annular lamination back iron and wherein annealing the selected portions of the oriented steel comprises:
annealing only selected lamination teeth wherein, prior to annealing, said selected lamination teeth have the superior magnetic properties which are not substantially radially aligned.
11. The method as recited in claim 10 wherein stacking the plurality of stator laminations comprises angularly staggering the stator laminations.
12. The method as recited in claim 1 wherein providing the motor stator core comprises stacking a plurality of stator laminations made from the oriented steel, wherein each stator lamination comprises an annular lamination back iron and a plurality of lamination teeth extending radially inward from the annular lamination back iron and wherein annealing the selected portions of the oriented steel comprises:
annealing only selected portions of the annular back iron wherein, prior to annealing, said selected portions of the annular back iron have the superior magnetic properties which are not substantially annularly aligned.
13. The method as recited in claim 12 wherein stacking the plurality of stator laminations comprises angularly staggering the stator laminations.