Electric machine with in slot cooling system

An electric machine comprising:

• a rotor rotatable about an axis;
• a stator operably coupled with the rotor, the stator including a stator core which is formed out of a stacked plurality of sheet metal laminations and defines a plurality of slots, each of the slots having an axial length and first and second axial end openings located at opposite axial ends of the slot;
• the stator further including a plurality of windings wherein at least one of the plurality of windings extends axially within each of the plurality of slots;
• and
• an elongate cooling conduit adapted to convey a liquid coolant therein, the conduit defining a plurality of projecting bends, each of the projecting bends having first and second axially extending and substantially parallel legs and an intermediate section connecting the first and second legs, each of the projecting bends being disposed in a respective one of the plurality of slots wherein the first leg is positioned to convey coolant into the one slot through the first axial end opening, the coolant being sequentially conveyed within the projecting bend through the first leg, the intermediate section and then the second leg, the second leg conveying the coolant out of the one slot through the first axial end opening, wherein the projecting bend is positioned radially adjacent the at least one winding disposed in the slot and wherein the projecting bend is in thermal communication with at least one of the stator core and the at least one winding disposed in the slot;
• and
• wherein the elongate conduit forming the plurality of projecting bends is a unitary length of conduit having a substantially uniform wall thickness and substantially uniform circumferential dimensions.

A method of manufacturing an electric machine, the method comprising:

• providing a stator core with a plurality of slots;
• providing a plurality of windings and installing at least one winding in each of the plurality of slots;
• forming a plurality of projecting bends in an elongate conduit and positioning each of the projecting bends in one of the plurality of slots wherein each projecting bend has first and second axially extending and substantially parallel legs and an intermediate section connecting the first and second legs, the first leg positioned to convey coolant into the slot proximate a first axial end of the stator core, the coolant being sequentially conveyed within the projecting bend through the first leg, the intermediate section and then the second leg, the second leg conveying the coolant out of the slot proximate the first axial end of the stator core and wherein the projecting bend is in thermal communication with at least one of the winding and the stator core;
• and
• operably coupling the stator assembly with a rotor assembly.