Internally shunting grounding brush assembly with axial brushes and centering bearings

A grounding brush assembly for an electric machine, the electric machine including a rotatable shaft rotatable about a central axis and having an inner circumferential surface defining a hollow bore, an outer housing, at least one bearing rotatably coupling the shaft with the housing, and a fixed shaft extending through the bore of the rotatable shaft and being electrically grounded, the grounding brush assembly comprising:

• a conductive base member including a cylindrical body with a bore sized to receive a portion of the fixed shaft and a centerline coaxially alignable with the central axis, the cylindrical body having a main body portion with an outer circumferential surface and a first outside diameter and at least one end body portion with a second outside diameter, the second outside diameter having a value less than a value of the first outside diameter;
• at least one centering bearing including an inner ring disposed about the at least one end body portion of the cylindrical body of the base member and an outer ring engageable with the inner circumferential surface of the rotatable shaft so as to center the rotatable shaft about the fixed shaft;
• and
• a plurality of conductive brushes each coupled with the main body portion of the conductive base member and spaced circumferentially apart about the centerline, each one of the plurality of conductive brushes including a plurality of conductive fibers extending radially outwardly from the outer surface of the main body portion of the base member and axially along the centerline, each conductive fiber having an inner radial end coupled with the cylindrical body of the base member and an outer radial end engageable with the inner circumferential surface of the rotatable shaft such that at least one conductive path extends from the rotatable shaft, through each one the plurality of brushes and the base member, and to the fixed shaft.