Tribological Properties Of Solid Lubricants Filled With Pitted Micro-texture On Cylinder Liner Surface

As a kind of power machinery,diesel engine has become the main power equipment because of its high efficiency,excellent economic performance and good adaptability.The wear of cylinder liner piston ring occupies a large proportion in various friction losses,which determines the working life and reliability of diesel engine.This paper carried out a study on the friction characteristics of the microtextured composite solid lubricant on the cylinder liner surface,mainly using theoretical analysis,simulation calculation and experimental demonstration to explore its influence on the friction properties of cast iron cylinder liner,and reveal the anti-friction mechanism.The main research contents are as follows:1.Simulation analysis of surface pitting micro-texture composite solid lubrication friction,using ANSYS to calculate the stress size and distribution of surface texture friction pairs with different geometric parameters under dry friction and solid lubrication,to measure the friction and wear between friction pairs from the perspective of stress.The results show that the stress distribution of circular texture is better than that of other textures.Compared with the smooth non-lubricated surface,the stress in the contact area is increased by the textured non-lubricated surface,and the stress distribution between the contacts is changed by the texture.Compared with the non-lubricated surface,texture lubrication can greatly reduce the stress in the contact area and alleviate the phenomenon of stress concentration.When the circular texture density is8.7%,the diameter is 400μm and the distribution Angle is 60°,the stress distribution and size of the cylinder liner surface are the best.2.Experimental study on laser processing technology of surface pitting micro-texture.The influence law of different laser processing parameters（output power,scanning times,scanning speed and frequency）on micro-texture depth and diameter was explored,and the process parameters of laser power of 25W,scanning times of 8,scanning speed of 500mm/s and frequency of 50k Hz were determined.The preset texture was machined on the surface of cast iron cylinder liner to realize the active design of micro-texture morphology and size.3.Lubrication and tribological properties of surface pitted micro-texture solid.By comparing different composite processes and combining with silane coupling agent,a new composite process was proposed,and the Mo S₂ composite solid lubricant with mass fraction of30%KH550 was determined to have better antifriction effect on cylinder liner surface.At the same time,the influence rule of texture shape and parameters（diameter,density and distribution Angle）on the friction properties of cylinder liner surface and the lubrication mechanism were explored.The research shows that compared with other samples,the lubrication effect of the texture lubrication surface is the best,and the friction coefficient reaches the minimum when the texture density is 12.5%,the diameter is 400μm and the distribution Angle is 60°.