EHL inlet zone analysis with the contact-lubricant interfacial limiting shear stress

摘要

Purpose - To develop a fairly different EHL inlet zone analysis for investigating the contact-lubricant interfacial limiting shear stress effect on line contact EHL film thickness in isothermal conditions. This analysis is purposed to give fast and qualitatively correct results. Design/methodology/approach - A Grubin-like EHL inlet zone analysis is derived with closed form of the analytical results of the EHL film thickness, the EHL film pressure, the contact-lubricant interfacial shear stress and the contact-lubricant interfacial slipping velocity in the EHL inlet zone based on the assumption of the contact-lubricant interfacial limiting shear stress in the EHL inlet zone. In this analysis, the lubricant is allowed to slip at the contact surface; The inlet contact surface shape is known from results referenced in this paper; The physical condition for the presence of the film slippage is incorporated; The lubricated area is divided into different kinds of film slippage zones where are, respectively, applied different governing equations. Three deterministic equations in this analysis are obtained and solving these coupled equations gives the solutions of the boundaries of the slip zone and the percentage reduction of the central film thickness by the contact-lubricant interfacial limiting shear stress effect in this EHL. Findings - Compared with the earlier approaches to the present problem, the present analysis has the advantage of giving fast and qualitatively correct solutions. The results obtained from the present analysis show that the contact-lubricant interfacial limiting shear stress effect on EHL film thickness is usually strong when the contact-lubricant interfacial limiting shear stress in the EHL inlet zone is low; This effect can greatly reduce the global EHL film thickness especially in severe operating conditions. Practical implications - A very useful material for the academic researcher and the engineer who are engaged in the study and measurement of the effect of the contact-lubricant interfacial limiting shear stress on EHL film thickness and EHL film pressure. Originality/value - A fairly different EHL inlet zone analysis is originally developed based on the assumption of the contact-lubricant interfacial limiting shear stress in the EHL inlet zone. The physical condition for the contact-lubricant interfacial slippage is first incorporated in this analysis. Deterministic governing equations in this analysis are derived and solving these coupled equations gives the final solutions of the present problem. This analysis has the advantage of giving fast and qualitatively correct solutions. It convincible shows the contact-lubricant interfacial limiting shear stress effect on EHL film thickness and EHL film pressure in the present EHL.