In order to explore the effect of TiN and TiAlN coatings on tribological properties and efficiency of gear, TiN and TiAlN coatings were deposited on 45 steel and the surface of gears by Arc Ion Plating technique. The dry tribological behavior of the substrate and coatings were tested in a ball-on-disk tribometer. The microcosmic morphology of the wear areas were observed by scanning electron microscope and energy dispersive spectrum. The wear mechanism of TiN and TiAlN coatings were investigated to assess the performance of the coatings. The efficiency of uncoated and coated gear was obtained and compared at various input rotating speeds. The results showed that TiN and TiAlN coatings provide a significant decrease of average friction coefficients compared with substrate. The wear mechanisms TiN and TiAlN coatings are mainly abrasive and adhesive wear, accompanied with adhesive and oxidation wear. The efficiency of gear has been significantly enhanced after TiN and TiAlN coatings deposition.

This article describes a new mixed transmission system about the wind power gearbox. It is composed of one NGW planetary gear stage and two parallel gear stages. The modeling and optimization analysis of gearbox have been performed using Romax designer software. The load case of gear, gear modification, transmission error and Fast Fourier Transform Harmonics of wind gearbox have been carried out to investigate various performances of gearbox system. Results of the investigation show the maximum load per unit length of gear reduces about 7.2%, Transmission Error of gear reduces 74.3% and Fast Fourier Transform Harmonics decreases 77.4% after gear modification. This kind of design method has a remarkable effect on smooth running. And it provides a new research method for gear box of wind turbine.