Much of the existing guidelines for making large, high-performance gears for wind turbine gearboxes exhibit a need for improvement. Consider: the large grinding stock used to compensate for heat treatment distortion can significantly reduce manufacturing productivity; and, materials and manufacturing processes are two other promising avenues to improvement. The work presented here investigates quenchable alloy steels that, combined with specifically developed Case-hardening and heat treatment processes, exhibits reduced distortion and, in turn, requires a smaller grinding stock.
It has long been known that the skiving
process for machining internal gears is
multiple times faster than shaping, and
more flexible than broaching, due to skiving's continuous chip removal capability. However, skiving has always presented a challenge to machines and tools. With the relatively low dynamic stiffness in the gear trains of mechanical machines, as well as the fast wear of uncoated cutters, skiving of cylindrical gears never achieved acceptance in shaping or hobbing, until recently.
It's not easy being big. Maybe that's not exactly how the phrase goes, but it's applicable, particularly when discussing the quality requirements of large gears. The size alone promises unique engineering challenges. BONUS Online Exclusive: Big or Small - Inspection is Key to Success.