Patent ID: 7146735

Claim:
A method of making a bearing ring for a large roller bearing the method comprising the steps of: (a) forming a bearing ring having at least one annular race centered on an axis and configured as an axial-bearing race; (b) rotating said bearing ring about the axis thereof while heating an entire annular surface layer of said annular race by juxtaposing said annular surface layer with an annular inductor centered on the axis and adapted to induce the heating of substantially all of said surface layer over a spacing between said inductor and said surface layer maintained during said heating; (c) quenching said bearing ring to harden said surface layer; and (d) controlling said spacing selectively so that said spacing is: (d1) 0.6 to 1 times the depth T of hardening of said surface layer for an axial-bearing race whose inner diameter corresponds to an inner diameter of the bearing ring at an outer edge of said axial-bearing race, 1.5 to 2 times the depth T of hardening of said surface layer for said axial-bearing race whose inner diameter corresponds to an inner diameter of the bearing ring at an inner edge of said axial-bearing-race, and varying continuously between said outer edge and said inner edge; and (d2) uniformly 0.6 to 1 times the depth T of hardening of said surface layer for an axial-bearing race whose inner diameter is greater than the diameter of the inner surface of the bearing ring.