The Effect of Lubricant Traction on Scuffing

Abstract

Abstract This paper presents the results of a disc machine gear simulation investigating the influence of lubricant traction characteristics and formulation on the load at which scuffing occurs. Scuffing theories in general link the onset of scuffing to the amount of heat generated in the contact and the authors hypothesized that reduced heat generation with low traction lubricants should lead to an increase in scuffing load. The study compared low traction PAO-based lubricants with mineral oils in basestock, antiwear and EP formulations and at both high (>6) and moderate (approximately 1.2) specific film thickness, λ. At λ > 6, the benefits of the synthetics over their mineral counterparts ranged from 25 percent to 220 percent and at λ ˜ 1.2, the benefits were a uniform 40 percent. It was particularly interesting to observe that the antiwear PAO-based oil gave a similar scuff load per unit contact width to an EP mineral gear oil. In addition, it was shown that scuffing load decreased with increasing traction coefficient to the power of approximately − 1.85, close to the −2.00 power predicted by the frictional power intensity concept. The agreement with flash temperature theory, with a predicted power of −1.33, was less close. Presented at the 47th Annual Meeting in Philadelphia, Pennsylvania May 4–7, 1992 Key Words: GearsEHLFlash TemperatureScuffingSynthetic LubricantsSynthetic Hydrocarbons Notes Presented at the 47th Annual Meeting in Philadelphia, Pennsylvania May 4–7, 1992