Study of contact pressure during the meshing process of rough surface gears considering elastic-plastic deformation of the asperity

Micro-topography plays a crucial role in determining actual surface contact pressure, but it is not clear how the variation pattern in contact pressure during the engagement of rough surface gears is. Based on assumptions about the geometry and distribution of micro-asperities in statistical rough surface contact theory, this paper employs an elastic-plastic contact model for micro-asperities. Through an iterative calculation method assuming pressure distribution, a method for calculating parameters such as contact pressure for rough curved surface is gained. The contact pressure of the rough surface gears during meshing is solved using an equivalent rough cylindrical surface contact at the meshing point, and the variation laws of contact pressure in the single and double tooth meshing areas are obtained. Analysis using measured tooth surface topography data reveals the following findings: (1) After being subjected to the elastic-plastic deformation condition of the asperity, at the borderline point of change for single-double tooth engagement, the average pressure mutation amplitude under rough surfaces is only 14.1% of that presented on smooth surfaces; (2) Increasing the density of surface asperities can effectively reduce the amplitude of contact pressure variation, improving the meshing stability in the critical area between single-double tooth meshing of gears. The proposed method in this paper for calculating contact pressure on the rough surface gears considering the elastic-plastic deformation of the asperity is novel for current related research, providing a foundation for studying the effect of tooth surface micro-topography on meshing stiffness and other related issues.