| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of an outer ring 2, effectively preventing generation of flaking to elongate a service life even if water enters into an internal space of a rolling bearing unit for supporting a vehicle wheel, and suppressing variation in service life, at low cost. SOLUTION: As material for forming the outer ring 2, columnar material 16 is used which makes distribution of non-metallic inclusions uneven. In a first step, an ultrasonic flaw detection of the columnar material 16 is performed to select the columnar material 16 in which there is no fault of a predetermined size or more. In a second step, out of the selected columnar material 16, only a portion of which cleanliness is secured in the first step and is higher than that of the other part, is used for forming surface parts of outer ring raceways 10, 10. Finally, in a third step, the ultrasonic flaw detection of the surface parts of the outer ring raceways 10, 10 is performed. Therefore, the above problem is solved. COPYRIGHT: (C)2009,JPO&INPIT
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