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In order to prolong rolling bearing fatigue life under mixed or boundary lubrication conditions, we have developed a specific smooth surface with small indentations by using the concept of micro EHL (elastohydrodynamic lubrication). These indentations or pits act as a carrier of lubricant from the inlet to the inside of the contact area. Therefore, lubrication performance of this surface is better than that of a superfinished surface. We have already demonstrated the ability of forming an oil film using this proposed surface. However, reliability of fatigue life for this surface was not sufficiently investigated. Therefore, we have conducted several rolling bearing fatigue life tests with this surface as compared to a superfinished surface. Lambda values of these tests were from 0.45 to 2.10. Results of these tests indicated that the life of the bearings containing rollers with this surface texture was between 2.0 to 13 times longer than that of normal bearings.

Peeling, which is composed of crowded minute cracks similar to shallow flaking, is a kind of rolling fatigue phenomena caused by an interference with surface asperities of the partner rolling element or a dust contaminated lubricant. In this paper, we describe experimental studies of peeling damage with metallic contact ratios defined by the electric resistance between the rolling elements, loading cycles and EHL film parameters. Damage leading to peeling failure starts to occur within 10 min of the loading cycle. Therefore, peeling grade after 4 h of running has a good correlation with the initial metallic contact ratio or EHL film parameter when compared to metallic contact ratio after 30 min.