波浪形织构对凸轮挺柱减摩抗磨性能的影响OA

As one of the three major friction pairs in internal combustion engines,the cam follower friction pair experiences severe wear on the follower surface due to excessive loads and complex lubrication conditions during operation,leading to reduced engine efficiency.To mitigate the effects of contact fatigue on the follower and ensure its performance,the work aims to provide an effective method for improving the tribological properties of cam followers. Given that laser surface texturing technology not only offers high production efficiency but also achieves processing accuracy at the micrometre or even nanometre level,the laser surface texturing technology was employed to prepare biomimetic wavy textures on the commonly used material GCr15 steel for lifters.By varying the texture spacing,the impact of biomimetic textures with different area fractions on the friction and wear resistance of GCr15 steel was investigated.Tests were conducted with a ball-disk testing machine under ball-disk contact conditions to simulate the point contact state of the cam-lifter pair.AISI 1045 steel balls were used as the counterface under test conditions including a load of 10 N,contact stress of 1.038 GPa,a speed of 150 r/min,an altitude of 1 900 m,ambient temperature and pressure,and oil lubrication.The samples were weighed multiple times before and after the test to calculate the wear amount.The friction coefficient automatically recorded by the testing machine was crucial for analyzing how texture affects friction and wear behaviour.Additionally,to conduct a more in-depth analysis,scanning electron microscopy,a three-dimensional profilometer,and an energy dispersive spectrometer were used to examine the surface morphology and elemental composition of the samples before and after wear.Additionally,the Fluent software was used to construct a finite element simulation model of the texture oil film,simulating the oil film pressure of textures with different spacings. Simulation and testing have shown that under the test conditions,the friction and wear resistance under all spacing textures is improved compared to the base material.Analysis of SEM and EDS detection results indicates that the primary wear mechanism is abrasive wear,with a small amount of oxidative wear.The wear depth and scratch width of textured samples are both reduced compared to non-textured samples.Samples with textured density within the range of 15%-20%exhibit better friction coefficients and wear rates,and the results from Fluent simulation modelling are consistent.This is because an excessively high textured area occupancy increases contact stress and wear,while an excessively low textured area occupancy results in low oil film pressure and poor fluid dynamic pressure effects. Following the aforementioned series of experiments and analyses,the following conclusions are drawn:laser-prepared biomimetic wavy surface textures are an effective means of enhancing the friction and wear resistance of GCr15 steel.Biomimetic wavy textures exhibit superior tribological properties by storing abrasive particles and providing fluid dynamic pressure to reduce friction coefficients and wear rates.It is also determined that the optimal tribological effect is achieved when the texture area ratio is between 15%and 20%.This work provides some insights for the optimized design of cam follower friction pairs in subsequent research.