US 12,258,642 B2
Method of induction-hardening a rolling-element bearing ring
Klaus Pedrotti, Münnerstadt (DE)
Assigned to AKTIEBOLAGET SKF, Gothenburg (SE)
Filed by AKTIEBOLAGET SKF, Gothenburg (SE)
Filed on Mar. 13, 2023, as Appl. No. 18/120,610.
Application 18/120,610 is a continuation of application No. 16/403,657, filed on May 6, 2019, abandoned.
Claims priority of application No. 102018207904.8 (DE), filed on May 18, 2018.
Prior Publication US 2023/0220505 A1, Jul. 13, 2023
Int. Cl. C21D 1/10 (2006.01); C21D 1/18 (2006.01); C21D 1/62 (2006.01); C21D 9/00 (2006.01); C21D 9/40 (2006.01); F16C 33/64 (2006.01)
CPC C21D 1/10 (2013.01) [C21D 1/18 (2013.01); C21D 1/62 (2013.01); C21D 9/40 (2013.01); F16C 33/64 (2013.01); C21D 9/0062 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method of induction-hardening a bearing ring, the method comprising the steps of:
providing a first inductor mounted on a first traversing element, a second inductor mounted on a second traversing element, and a preheating inductor mounted on a third traversing element;
positioning the first and second inductors at a start zone on the bearing ring;
positioning the preheat inductor in an end zone on the bearing ring spaced one hundred eighty degrees from the start zone;
operating the first traversing element such that the first inductor is moved circumferentially from the start zone toward the end zone along a first half of the circumference of the bearing ring while the first inductor heats the bearing ring;
operating the second traversing element such that the second inductor is moved circumferentially from the start zone toward the end zone along a second half of the circumference of the bearing ring while the second inductor heats the bearing ring; and
operating the third traversing element such that the preheat inductor moves circumferentially within the end zone so as to traverse a portion of each one of the first and second halves of the circumference of the bearing ring while the preheat inductor heats the end zone of the bearing ring;
wherein the step of operating the third traversing element includes moving the preheat inductor circumferentially back and forth within the end zone.