Multi-megawatt wind turbine gearboxes operate under demandingenvironmental conditions including considerable variation intemperature, wind speed, and air quality. It is not uncommon forgearboxes rated for a maintenance free 20-year lifespan to failafter only a few years. These gearboxes experience several types ofrepairable damage including micropitting or “gray staining”,abrasive wear, foreign object debris (FOD) damage, surfacecorrosion and fretting corrosion. Wear is greatest on the inputstage, especially on the sun pinion gear. Historically, grinding isutilized to refurbish these damaged gears. However, there arenumerous drawbacks including but not limited to high capitalinvestment and the extraordinary amount of time and skill involvedin the grinding process. Moreover, nitrided gears cannot be groundand must be scrapped. However, chemically accelerated vibratoryfinishing, or isotropic superfinishing (ISF), represents a valueadding, low-cost option for refurbishing both case carburized andnitrided gears. Isotropic superfinishing removes light to moderategear flank surface damage. The result is a surface with anon-directional pattern with a roughness of approximately 0.08 mmor less. Moreover, evidence suggests that isotropic superfinishingimparts a finish that increases gear durability and service life inthe field. A case study on a sun pinion gear is presented.
- Edition:
- 10
- Published:
- 10/01/2010
- Number of Pages:
- 10
- File Size:
- 1 file , 470 KB
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