Electric drive unit cooling systems and methods

A method of use in an electric drive unit, the electric drive unit including a housing, a stator within the housing wherein the stator defines an outer side surface and includes first stator end-windings and second stator end-windings, at least one annular stator cooling ring encircling the outer side surface of the stator, a first annular jet ring adjacent to and at least partially encircling the first stator end-windings and defining a first plurality of holes therein, a second annular jet ring adjacent to and at least partially encircling the second stator end-windings and defining a second plurality of holes therein, a first plurality of stator cooling channels extending radially from the annular stator cooling ring to the first annular jet ring, and a second plurality of stator cooling channels extending radially from the at least one annular stator cooling ring to the second annular jet ring, wherein an oil distribution assembly including the at least one annular stator cooling ring, the first plurality of stator cooling channels and the second plurality of stator cooling channels is formed as a unit and the unitary oil distribution assembly is between the stator and the housing and separate from the housing and the stator, the method comprising:

• positioning the unitary oil distribution assembly around the stator;
• initially providing oil through an aperture defined in the housing and into the at least one annular stator cooling ring of the unitary oil distribution assembly;
• subsequently providing oil through the at least one annular stator cooling ring and into the first plurality of stator cooling channels and into the second plurality of stator cooling channels;
• providing oil through the first plurality of stator cooling channels and into a first space defined between the housing and the first annular jet ring;
• providing oil through the second plurality of stator cooling channels and into a second space defined between the housing and the second annular jet ring;
• providing oil through the first plurality of holes onto the first stator end-windings;
• and
• providing oil through the second plurality of holes onto the second stator end-windings.

A method of assembling an electric drive unit, the electric drive unit including a housing, a stator wherein the stator defines a first end a second end and an outer side surface and includes first stator end-windings and second stator end-windings, at least one annular stator cooling ring, a first annular jet ring defining a plurality of first holes therein, a second annular jet ring defining a plurality of second holes therein, a first plurality of stator cooling channels, and a second plurality of stator cooling channels, the method comprising:

• positioning the at least one annular stator cooling ring to encircle the outer side surface of the stator;
• positioning the first annular jet ring adjacent the first stator end-windings and adjacent the first end of the stator;
• positioning the second annular jet ring adjacent the second stator end-windings and adjacent the second end of the stator;
• positioning the first plurality of stator cooling channels to at least partially encircle the outer side surface of the stator and extend from the at least one annular stator cooling ring to the first annular jet ring;
• positioning the second plurality of stator cooling channels to at least partially encircle the outer side surface of the stator and extend from the at least one annular stator cooling ring to the second annular jet ring;
• and
• positioning the stator, at least one annular stator cooling ring, first annular jet ring, second annular jet ring, first plurality of stator cooling channels and second plurality of stator cooling channels in the housing, wherein an oil distribution assembly including the at least one annular stator cooling ring, the first plurality of stator cooling channels and the second plurality of stator cooling channels is formed as a unit between the stator and the housing and is separate from the housing and the stator.