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	弾性流体潤滑	公差重ね合わせ
分野	製造工学	製造工学
系統	Process / pipeline	Process / pipeline
提唱年	1977	2006
提唱者	Dowson, D., Higginson, G. R.	Drake, P. J.
種類	Mathematical model for lubricated contacts	Method for analyzing tolerance accumulation in assemblies
原典	Dowson, D., & Higginson, G. R. (1977). Elastohydrodynamic Lubrication: The Fundamentals of Roller and Gear Lubrication. Pergamon Press. ISBN: 0-08-021710-4	Drake, P. J. (2006). Dimensioning and Tolerancing Handbook (2nd ed.). McGraw-Hill. ISBN: 0-07-145215-8
別名	EHL, Elastohydrodynamic film, Hydrodynamic lubrication	Stack-up analysis, Tolerance accumulation, Geometric tolerance
関連	4	4
概要	Elastohydrodynamic lubrication (EHL) is the regime of fluid film lubrication in which elastic deformation of the surfaces plays a crucial role in maintaining a fluid layer between sliding or rolling surfaces. In applications like roller bearings and gears, the contact pressure is extremely high, causing the lubricant viscosity to increase dramatically and the surfaces to deform elastically. EHL theory, developed rigorously by Dowson and Higginson, predicts the film thickness, pressure distribution, and friction in these heavily loaded contacts.	Tolerance stack-up analysis is a method for predicting the cumulative effect of manufacturing tolerances on the final dimensions and fit of assembled components. When parts with individual tolerances are assembled together, their tolerances combine in complex ways, often producing a result that is worse than each part individually. Stack-up analysis ensures that the final assembly will function correctly despite individual part tolerances, or identifies where tighter tolerances are necessary.