Simulation Of Tooth Surface Wear And Its Effect On Friction Characteristics Considering Axis Parallelism Error

Gear transmission has been widely used in various mechanical engineering fields because of its high reliability,strong bearing capacity and various transmission forms.However,the assemble error is inevitable in the gear system,especially the axis parallelism error in the vertical plane,which seriously affects the meshing characteristics of the gear pair.The parallelism error will cause offset load of tooth surface,which will cause edge contact and stress concentration,and result in the increase of tooth contact deviation.At the same time,the uneven load distribution will cause serious uneven wear on the tooth surface,and the change of tooth profile geometry caused by uneven wear will also affect the lubrication and friction characteristics of the tooth surface.On the contrary,the change of tooth surface lubrication state will further affect the tooth surface wear,and accelerating the gear wear failure process.Therefore,it is of great significance to study the wear distribution of the tooth surface considering the axis parallelism error and its influence on the friction characteristics of tooth surface is of great significance.The main work of this paper is as follows:(1)The contact clearance and the radius of curvature of the meshing point were calculated with the axis parallelism error.Based on the basic equation of the contact problem,a onedimensional numerical calculation model of the gear contact stress considering the axis parallelism error was established and compared with the national standard calculation method under the ideal assemble condition.The results show that the numerical calculation results are in good agreement with those calculated by national standard,and can reflect the actual contact situation better.When the axis parallelism error exists,the tooth surface will be biased.With the increase of the error,one side of the gear will have contact separation.The increase of load can improve the uneven contact phenomenon of the tooth surface.(2)The process of tooth wear was discretized.Based on Archard wear theory and the established numerical calculation model of gear contact stress,a tooth wear analysis model considering the axis parallelism error was established to calculate the parameters of tooth wear and analyze the influence of wear on tooth contact characteristics.The results show that when the axis parallelism error exists,the wear depth at the edge contact position of the driving gear root is the largest,and the wear depth at the node is the smallest.The wear can improve the uneven distribution of the toothed load to a certain extent,and the maximum contact stress moves towards the center of the tooth width with the increase of the wear.(3)Based on the gear contact analysis model and tooth surface wear model,a gear lubrication and friction characteristics analysis model was established considering the axis parallelism error and tooth surface wear,and the effects of parallelism error and wear on the lubrication state,friction coefficient and friction force of tooth surface were discussed.The results show that the axis parallelism error will aggravate the lubrication state of the gear,and with the increase of the axis parallelism error,the friction coefficient and friction force will also increase,but the increase range is small.Wear can improve the aggravation of lubrication state caused by the axis parallelism error to a certain extent,and make the friction coefficient distribution along the tooth width more uniform.Both the friction coefficient and friction force will decrease with the increase of wear,but the reduction is very small.