The Optimization Design Of Large Journal Bearing Under Low-speed And Heavy-duty Conditions Based On Reverse

Large low-speed heavy-duty journal bearings as a key component of heavy machinery and equipment has many characteristics such as high load capacity,low power dissipation,impact resistance and high anti-shaking.It can work in a severe environment for a long time,such as slewing bearing of offshore platform crane.For large heavy-duty journal bearings can not generate a complete lubricant film or the minimum thickness of oil film is too thin,resulting in dry friction,semi-dry friction,boundary lubrication between the bearings and shafts,which also cause the wear of bearing.So it is necessary to analyze the contact problem of the bearing.Owing to the contact problem,an optimized design of large low-speed heavy-duty journal bearing based on reverse was proposed in this paper,which purpose is to improve the comprehensive performance and life of the bearing.The main contents are as follows:First,through the introduction and analysis of the bearing contact state in detail,the reverse thinking process about the contact problem has been established.In this process,it involves the Hertz contact theory,hydrodynamic lubrication principle and the basic principles of EHL for obtaining the main forms of contact and their carrying capacity.Then,based on the theory into the example of calculation and analysis,taking the offshore platform crane slewing bearing as an example,the maximum contact stress and strain value and the stress and strain distribution under static state are calculated by ANSYS model.The value of oil film pressure and the oil film thickness under hydrodynamic lubrication are obtained by MATLAB numerical calculation.Meanwhile,the influences of various factors such as the ratio of width to diameter,eccentricity and rotation speed to the journal bearing are analyzed,which provides the basis for the optimization.On the basis of reverse engineering,the elastic contact of the journal bearing is optimized and analyzed by reducing the contact stress and the amount of wear.In this paper,the maximum wear of bearing is obtained when the maximum contact stress is converted into experimental force,and studies the influence of load,velocity and grease lubrication conditions on tribological properties of the sliding bearing material,such as friction coefficient,friction force and wear rate.Tribology tests was conducted on MMW-1 vertical multifunctional tribometer.As for fluid lubrication contact optimization,the genetic algorithm(GA)is used to carry out the multi-objective Optimize to get the journal bearing with the best overall performance.On the basis of the reverse,it takes the result of reverse design as the initial design variables,the bearing capacity,the frictional force and the oil discharge quantity as the objective function,the contact pressure and minimum oil film thickness as the constraints condition.