METHOD FOR FORMING QUENCHED HARDENED LAYER OF OUTER RING OF HUB UNIT BEARING

PROBLEM TO BE SOLVED: To provide a method for forming a hardened layer of the outer ring of a hub unit bearing, which forms the hardened layer of the outer ring inner peripheral surface to prevent hardening in the vicinity of the inner peripheral opening part of a mounting hole formed between double-row inner peripheral raceways using not a special shaped but a simple shaped quenched coil when the quenched hardened layer of the outer ring inner peripheral surface is formed. SOLUTION: In the method for forming the quenched hardened layer of the outer ring inner peripheral surface of the hub unit bearing, a radiation jig made of metal having thermal conductivity higher than that of copper which is a material for the outer ring is mounted on the mounting hole of a sensor provided from the inner peripheral surface of the outer ring radially outward. The inner peripheral surface is heated from radially inward of the outer ring. The quenched hardened layer is formed in the inner peripheral surface of the outer ring containing a first inner peripheral raceway and a second inner peripheral raceway. On this occasion, the vicinity of the inner peripheral opening part of the mounting hole is made lower in hardness, compared with the inner peripheral surface between the first inner peripheral raceway and the second inner peripheral surface. COPYRIGHT: (C)2009,JPO&INPIT