2024-02-29 23:00:00
The development of the theory of elastohydrodynamic lubrication – with the understanding of the complex phenomena it involves – is one of the major advances in the field of tribology during the 20th century.e century. The revelation of the existence of a previously unsuspected lubricating film has revolutionized this science, explaining the remarkable effectiveness of lubrication in radio contacts.
Elastohydrodynamic (EHD) lubrication occurs in contacts subject to a punching effect (non-compliant surfaces), with very high local pressures, primarily in bearings, gears and cam devices. The EHD theory makes it possible to calculate the thickness of the oil film in the radio contacts, which makes it possible to predict the lifespan of the mechanisms.
In these contacts subjected to a high load, the local elastic deformation of the facing surfaces modifies the geometry of the parts in the vicinity of the contact. The hydrodynamic balance is then governed not only by the Reynolds equation, but also by the piezoviscosity of the oil and by the Hertz theory, which makes it possible to generate films of sufficient thickness to separate the parts and limit their friction and wear. This is therefore a very important area for its practical applications: EHD theory now makes it possible to rationally design bearings, gears and cam devices, optimizing the contact geometry and operating conditions to maximize the thickness of the oil film.
However, two phenomena occur which contribute to reducing the thickness of the lubricating film and which are localized at the entrance to the contact: thermal effects and power conditions. Current models propose corrective factors which reflect the reduction in the thickness of the lubricating film caused by these two phenomena.
This article presents the development of this theory and its advances until the early 2010s.
1709356776
#Elastohydrodynamic #lubrication #Complete #file