AGMA 98FTM8

For maximum energy savings low viscosity lubricants arefrequently used. Increasing transmitted power leads to highertemperatures and thus thinner lubricating films. These tendenciesincrease the failure probability in gear contacts with respect towear, scuffing, micropitting and pitting performance. New testmethods on modified FZG gear test rigs were developed to evaluatethe load carrying capability of gear lubricants. For the low speedregime a wear test using C-type gears at low pitch line velocity of0.05 m/s, and two different temperatures of 90 and 120 5C toconsider different additive response at high loading of load stage12 (C/0.05/90:120/12) was developed and applied to many differentlubricants. New scuffing procedures for gear lubricants of scuffingperformance between API GL 3 and GL 5 were developed. The step testA10/16.6R/90 uses A-type gears of 10 mm pinion face width at 16.6m/s pitch line velocity with a driven pinion. A discrimination ofall gear oils up to the level of API GL 4 is possible. A shock testS-A10/16.6R/90 with direct loading in the expected load stagediscriminates between GL 4 and GL 5 lubricants. Different standardpitting tests are available for different lubricant viscositygrades using C-type gears at 8.3 m/s pitch line velocity and 90 5Cin load stages 9 (PT C/9/90) or 10 (PT C/10/90). For automotiveapplications load spectrum testing is possible at low (PT C/LLS/90)and high (PT C/HLS/90) loads. For applications with long oil drainintervals a combined pitting and oil ageing test was developed(PITS C i85 TS) using C-type gears at variable load, speed andtemperature conditions. At high temperature conditions between 120and 150 5C the oil ageing properties together with their influenceon pitting characteristics is evaluated in correlation to areference oil. The test methods are described. Test results withdifferent market products are discussed.

Edition:

98

Published:

10/01/1998

Number of Pages:

12

File Size:

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