4. Title and Subtitle ELASTOHYDRODYNAMIC FILM THICKNESS BETWEEN ROLLING DISKS WITH A SYNTHETIC PARAFFINIC OIL

Elastohydrodynamic (EHD) film thickness measurements were made in an X-ray rolling-disk machine with a synthetic paraffinic oil a t temperatures from 339 to 589 K (150 ' t o 600 ' F). The synthetic paraffinic oil both with and without an organic phosphonate antiwear additive is capable of providing an EHD film throughout the range of tes t conditions. The measured film thicknesses were less than predicted by EHD theory when the lubricant was used without the antiwear addi tive. The antiwear additive caused an increase in the measured EHD film thickness. The mea sured film thickness was more sensitive to contact stress than predicted by EHD theory. For the oil without the antiwear additive, variations of measured film thickness with speed and vis cosity were similar to those predicted by EHD theory. The film thickness measurements veri fied results of 120-mm- and 25-mm-bore ball bearing tests with the same lubricant. 17. Key Words (Suggested by Author(s) ) 18. Distribution Statement Bearings Ball bearings Lubrication High-temperature Unclassified- unlimite