Inductor for inductively heating raceways of antifriction bearing rings

Inductive heating apparatus in combination with a bearing ring, the inductive apparatus being specifically for heating inductively low friction planar bearing surfaces and transition areas adjacent to the bearing surfaces on the bearing ring in order to harden the bearing surfaces without distortion, wherein the bearing surfaces are on a substantially rectangular projection on the inner surface of the bearing ring and include an axial bearing surface and parallel radial bearing surfaces, the transitional areas being areas on the inner surface of the bearing ring adjacent to the projection, the combination comprising:

• a toroidal inductor formed of two opposed and parallel U-shaped sections joined by U-shaped bights wherein each U-shaped section includes a straight bight and a pair of legs depending therefrom which legs converge toward one another before termination in the U-shaped bights which join the legs of the U-shaped sections, and
• localized flux concentrators mounted on the U-shaped bights to increase the intensity of the field adjacent to the bights;
• wherein,
• the straight bights are juxtaposed with the axial bearing surface of the projection, the legs are juxtaposed with the parallel radial bearing surfaces of the projection and the U-shaped bights extend adjacent to the transitional areas on the inner surface of the ring, whereby hardening due to induction heating occurs simultaneously to all bearing surfaces and to the transitional area thus avoiding stress distortion between the projection and transitional area due to localized heating thereof.