Electric machine and electrically-assisted turbocharger including the same

An electric machine for an electrically-assisted turbocharger including a shaft, said electric machine comprising;

• a rotor extending along an axis and configured to be rotatably coupled to the shaft;
• a stator lamination stack radially spaced from said rotor such that said rotor is configured to be radially disposed between the shaft and said stator lamination stack, with said stator lamination stack having,
• a first stator end;
• a second stator end spaced from said first stator end;
• and
• a plurality of circumferentially spaced teeth extending between said first and second stator ends radially with respect to said axis, said plurality of circumferentially spaced teeth defining gaps therebetween;
• a coil winding disposed in said gaps between said circumferentially spaced teeth of said stator lamination stack;
• and
• a guard plate disposed at one of said first and second stator ends of said stator lamination stack, said guard plate extending radially away from said axis and comprising a plurality of teeth guards extending radially with respect to said axis,
• wherein each of said plurality of teeth guards is aligned with one of said plurality of teeth of said stator lamination stack to electrically insulate said coil winding from said plurality of teeth of said stator lamination stack;
• and
• wherein said teeth of said stator lamination stack extend radially inward toward said axis and said teeth guards of said guard plate extend radially inward toward said axis.

A method of manufacturing an electrically-assisted turbocharger, the electrically-assisted turbocharger including a shaft extending along an axis between a first shaft end and a second shaft end spaced from the first shaft end along the axis, a compressor wheel coupled to the first shaft end of the shaft, a turbine wheel coupled to the second shaft end of the shaft, a housing disposed about the shaft and defining a housing interior, and an electric machine disposed about the shaft in the housing interior of said housing, the electric machine including a rotor extending along the axis and rotatably coupled to the shaft, a stator lamination stack radially spaced from the rotor such that the rotor is radially disposed between the shaft and the stator lamination stack, with the stator lamination stack having a first stator end proximate to the compressor wheel, a second stator end spaced from the first stator end and proximate to the turbine wheel, and a plurality of circumferentially spaced teeth extending between the first and second stator ends, with the plurality of circumferentially spaced teeth extending radially with respect to the axis, and with the plurality of circumferentially spaced teeth defining gaps therebetween, a coil winding disposed in the gaps between the circumferentially spaced teeth of the stator lamination stack, and a guard plate disposed at one of the first and second stator ends of the stator lamination stack, the guard plate extending radially away from the axis and comprising a plurality of teeth guards extending radially with respect to the axis, each of the plurality of teeth guards being aligned with one of the plurality of teeth of the stator lamination stack, said method comprising the steps of:

• coupling the guard plate to one of the first and second stator ends of the stator lamination stack;
• inserting the coil winding in the gaps defined by the circumferentially spaced teeth of the stator lamination stack;
• and
• compacting the coil winding against the teeth guards of the guard plate to electrically insulate the coil winding from the plurality of teeth of the stator lamination stack.