Study On Elastohydrodynamic Oil Lubrication Of Parallel Line Gear Pair

The line gear(LG)that achieves transmission through continuous point-contact meshing is a novel type of gear based on space curve meshing theory.When the transmission mode is parallel shaft transmission,pure rolling meshing can be achieved,which has the advantages of flexible design and high transmission efficiency.In recent years,design theory and processing technology of LG have been greatly developed,and preliminary progress has also been made in the application field.However,the research on LG in the field of lubrication design has not been completed,mainly manifested in: the current LG lubrication design theory does not take the influence of assembly misalignment and roughness of gears into consideration,and the parameter selection criteria based on this lubrication design theory are only applicable for the LG pair under the normal surface arc tooth profile,this tooth profile makes the LG pair prone to end leakage of lubricating oil and poor carrying capacity,which is not conducive to achieve elastohydrodynamic lubrication(EHL).In this dissertation,theoretical and experimental researches are carried out on the EHL performance of parallel line gear(PLG)from three aspects: the assembly misalignment of the PLG pair,the tooth surface roughness and the tooth profile design.The main research contents are as follows:1.By studying the geometric model and operating conditions of the meshing point of the PLG pair considering the assembly misalignment,the influence of various types of assembly misalignments of the gear pair on the contact model is analyzed.2.A numerical calculation model of elastohydrodynamic lubrication of PLG pairs is established considering the tooth surface roughness and the assembly misalignment.The influence of roughness model,roughness amplitude and assembly misalignment on the EHL state of PLG pair is analyzed by a numerical example.3.The parametric design theory of the new tooth profile,that is,the eccentric arc tooth profile PLG pair on the end face,is studied,and the influence of each design parameter on the lubrication performance is analyzed,and the parameter optimization criterion under this tooth profile is proposed.The tooth surface contact equivalent models of the normal surface arc and the end surface eccentric arc are compared and analyzed,and the lubricating performance of the gear pair under the two tooth profiles is judged.In addition,a numerical example is also used to illustrate that the gear pair with the eccentric circular arc tooth profile on the end face belongs to center distance separable gear pair.4.According to the characteristics of the contact model,the numerical calculation model of the EHL of the PLG pair with the eccentric arc tooth profile on the end face is established,and it is verified by the optical interference film thickness measurement experiment.In addition,through the numerical calculation and film thickness measurement experiment,the lubrication state of the PLG pair with the arc tooth profile on the normal face and the eccentric arc tooth profile on the end face under the same contact line and gear pair application conditions was visually compared.The eccentric circular arc tooth profile on the end face after optimized parameter design has better lubricating performance than the circular arc tooth profile on the normal face.