| 摘要 |
PROBLEM TO BE SOLVED: To improve the rolling fatigue life of a wheel supporting rolling bearing unit. SOLUTION: This rolling bearing unit outer ring manufacturing method comprises a step of applying hot machining to a steel raw material into the shape of an outer ring 3 and then cooling it at a cooling speed lower than a lower critical cooling speed in a continuous cooling transformation diagram to produce a pearlite and ferrite metal structure with a ferrite area rate of 7% or less, a step of applying high frequency quenching to outer ring raceway surfaces 3a, 3b at such a temperature that a surface layer forming an outer diameter face 3c of the outer ring is at lower than an Ac1 transformation point and then applying tempering thereto, and a step of grinding the outer ring raceway surfaces, in sequence. COPYRIGHT: (C)2007,JPO&INPIT
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