Effects of viscosity and surface roughness on gear contact tribological layers

Abstract

The increasing dependence on more robust additive chemistry to improve gear pitting resistance requires the additive technology development to rely less on a trial-and-error approach and more on a better basic understanding of the influence of additive chemistry on tribological contact layers' physical and chemical changes. The use of secondary neutral mass spectrometry (SNMS) and nanoindenter to analyse tribological contact layers had been carried out by Inacker and co-workers at NMI. They found that the alkyl structure of zinc dithiophosphate (ZDTP) and the type of cation have a profound effect on the thickness and nanohardness of the tribological layer. An extension to that study has been carried out in this investigation, which involves a design experiment of two variables (oil viscosity and surface roughness) while keeping the additive chemistry constant to determine their impact on the tribological layer. The methods used to analyse the tribological layers include SNMS, nanoindenter and SEM coupled with focused ion beam imaging of the rectangular well-shaped cross section. The results in general are in agreement with the findings of Inacker and his co-workers, namely greater micropitting reduces the thickness of the tribological layer and brings closer the depth of nanohardness maximum to the surface.

Study on the tribological behaviors of copper nanoparticles in three kinds of commercially available lubricants

“…It may be because Cu NPs are added to the oil and the relative motion between the oil layers happens more easily; as a result, a little reduction occurred in viscosity (Ettefaghi et al, 2013). Besides, proper viscosity lubricating oil could help to form a better oil film (Jao et al, 2007;Selway et al, 2017), and the addition of Cu NPs may help to form a copper protective film.…”

Influence of surface functional parameters on friction behavior and elastic–plastic deformation of grinding surface in mixed lubrication state

“…Second, surface textures and surface roughness parameters were extracted. Third, flow factors for these surfaces were calculated using equations (2) and (3). Finally, the equations of the flow factors with statistical significance were obtained using the nonlinear least squares fitting method.…”

“…Therefore, for energy saving and reducing material consumption, it is necessary to decrease friction coefficients, improve lubricating properties, and reduce wear. 1,2 Especially for the larger bearing parts such as sliding guideways, reducing the friction coefficient and improving lubricating effects can obviously increase service life. 3 Generally, methods such as improving surface quality, selecting suitable contact material, and choosing an appropriate lubricant can be used to reduce friction and wear.…”

Meshing impact analysis of planetary transmission system considering the influence of multiple errors and its effect on the load sharing and dynamic load factor characteristics of the system

“…2 studied the influence mechanism and mutual relationship between corner contact and transmission error of single-pair gear, deduced their quantitative calculation formula, and carried out the necessary verification and analysis on their reasonable effectiveness. Jao 3 and Xiao and Tang 4,5 analysed the meshing impact on a pair of gears, and selected the design parameters of the gear in a reasonable and scientific way, which minimized the meshing impact speed of the meshing gear and significantly reduced the gear transmission noise. Zhou et al.…”