Study On The Surface Biomimetic Texture Design Of Roller Drill Sliding Bearing And Its Lubrication Performance

As the ’ bridge ’ between the roller bit working part and the power input end,the roller bit sliding bearing is the weakest link in its work.How to improve the working stability of roller bit sliding bearing is one of the urgent problems to be solved to prolong the working time of roller bit.Therefore,this paper aims to explore a friction reduction and drag reduction technology for the friction contact surface of roller bit sliding bearing,in order to improve the working performance of roller bit sliding bearing.Firstly,the force characteristics of the roller bit sliding bearing are explored from the mechanical and hydrodynamic analysis models.The contact behavior of the roller bit sliding bearing is theoretically studied by Reynolds equation,nonlinear finite element theory and tribology theory.The mathematical model of hydrodynamic lubrication and the friction and wear simulation model of contact pair are established.Then,based on the bionic idea of bionic tribological surface morphology,the bionic structure of shark scale shield pit was created,and the hydrodynamic pressure mathematical model and friction and wear simulation model considering bionic texture were established.Secondly,the Reynolds equation and friction and wear simulation model considering bionic texture are numerically simulated and analyzed,and the optimal structural parameters of bionic structure are selected.The selected optimal imitation structure is explored and analyzed under multiple working conditions,and its lubrication and friction reduction performance under different loads,speeds and friction coefficients is studied.The analysis shows that the optimal area ratio of bionic structure is 0.45 and the depth-diameter ratio is 0.2.Under the condition of hydrodynamic lubrication with eccentricity of 0.5,the oil film bearing capacity is increased by 55.21 %.The wear volume decreased by 18.95 % in the solid friction stage,and the friction stress decreased by 63.05 % in the normal wear stage.At the same time,in the hydrodynamic lubrication stage,with the increase of eccentricity,the effect of oil film bearing capacity is more obvious.Compared with the non-textured sliding bearing,the hydrodynamic oil film has higher load stability under load impact.Under various working conditions in the solid friction stage,the bionic shark scale shield texture sliding bearing friction contact pair has better and more stable friction performance than the non-texture sliding bearing.Finally,through the equivalent principle,the actual working condition parameters are transformed into laboratory tests to explore the effect of bionic texture on friction reduction and drag reduction under complex lubrication conditions.The results show that the bionic shark scale shield texture can improve the friction performance of the friction pair.Compared with the non-textured friction pair,the friction coefficient is reduced by 21.27 %,the wear loss is reduced by 29.50 %,and the temperature rise is reduced by 42.16 %.Through the exploration of the wear mechanism of the bionic texture,it is found that the bionic texture improves the hydrodynamic lubrication effect of the roller bit sliding bearing,and captures the wear debris to reduce the occurrence of wear debris.The load factor has a more significant effect on the wear performance of the friction pair than the speed factor.The greater the load,the weaker the wear resistance of the friction pair.