| 摘要 |
A bearing for a rocker arm includes a shaft corresponding to an inner race fixed to a rocker arm interposed between an engine valve and a cam to adjust intake and exhaust, an outer race 4 in contact with the cam, located outer to the inner race, and a plurality of needle rollers located between the outer race and the inner race. The outer race includes a nitrogen-enriched layer. The grain size number of austenite crystal grains in the nitrogen-enriched layer is in a range exceeding No. 10. The outer race outside cylindrical surface has random small concave pits.
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