Patent ID: 8829744

Claim:
An electric machine comprising: a stator having an outer circumference; spaced apart first walls arranged about the outer circumference providing generally parallel axially extending first channels, and a second wall adjoining the first walls and arranged about the outer circumference providing discrete, arcuate second channels in fluid communication with the first channels and providing a tortuous serpentine fluid flow path about the circumference that is configured to alternate between opposite axial fluid flow directions within the first channels, the first and second channels having an inner surface; and a structure provided within at least one of the first and second channels and having an outer surface spaced radially outward from the inner surface to provide a flow passage and at least partially defining the tortuous fluid flow path between the outer and inner surfaces, wherein the structure is provided by a fin core including rows of corrugations, the corrugations include spaced apart legs and the outer surface, which is supported by the legs, the flow passage is defined by the inner and outer surfaces and the spaced apart legs.