measuring the ehd film thickness in a rotating ball

THE use of Newton rings for the measurement of oil film thickness in point or line contact is rendered difficult by the similarity of the refractive index of normal glass and oil For this reason it is usually applied when the lubricant is not oil (Skinner 1 used glycerine) or when one of the surfaces is not glass Recently Kirk 2/SUP has used interferometry with `Perspex' this limits the In this paper the EHL oil film thickness and shape between a needle roller and a flat rectangular glass in pure rolling oscillated working conditions had been measured based on optical interferometry The EHL behavior affected by the applied load oscillating frequency was investigated The typical film shape varies of interference pictures on the maximum needle roller rotation velocity was

Process of Boundary Film Formation from Fatty Acid Solution

To measure the thickness of thin films formed by lubricating fluids ultrathin-film interferometry was used [13 14] The setup is shown schematically in Fig 1 A lubricated contact is formed between a loaded steel ball and a flat surface of a glass disk The disk is driven and can drive the ball in nominally pure rolling on a ball

EHL theory learns that the film thickness is mainly determined by the conditions in the inlet of the con-tact see Ertel [17] and Dowson and Higginson [13] Film pressures in the inlet are lower than that in the narrowest part of the film the conjunction zone So for film thickness calculations the pressure–viscosity

Fig 2: Validation of numerical simulations by experiments (here film thickness measurements) in rolling sliding and spinning lubricated contacts Left: FEM solution on the left interferometric picture on the right for a ball-on-disk contact U 0 = 2 m/s W=400 N

distribution in EHD contacts in detail it has been applied to measure the minimum (or central) oil film thickness under non-steady states (11–14) abnormal film shapes (15 16) or temporal change in the thickness of adsorbed films (17) How-ever to apply the optical method it is necessary to use a trans-parent material that transmits light

Experimental Rig for Measuring Lubricant Film Thickness in Rolling Bearings Xingnan Zhang1 a Karolina Jablonka2 b and Romeo Glovnea1 c* 1Department of Engineering and Design University of Sussex United Kingdom 2 AC2T research Viktor Kaplan-Strae 2D 2700 Wiener Neustadt Austria aXingnan Zhangsussex ac uk cR P Glovneasussex ac uk

TEMPERATURE AND SHEAR STRESS IN ROLLING/ SLIDING

rheology is to set up a steady-state EHD film generally in a twin disc or ball on flat contact and to measure friction over a range of rolling/sliding/spin conditions [3 19-25] The ratio of the friction to the mean contact pressure then provides a measure of the mean shear stress of the film within the contact Also if the film

Elastohydrodynamic lubrication a (ehl) is a comparatively recent branch of tribilogy which only became properly established in the early nineteen sixties It is the mechanism that describes the separation by a lubricant film between two elastic machine elements loaded against each other and in relative motion

This can then lead to less definable transitions between the layers to be measured in the subsequent optical measurement with the microscope The PAINTXPLORER 548 is designed as a comfortable tabletop unit It comes with an improved high precision rotating/sliding axle

The Model C Wet Film Thickness gauge is a precision instrument for use in the laboratory the field and on the production line It accurately measures the wet film thickness of paint varnishes lacquers adhesives inks gel coats and almost any type of wet film applied to flat or cylindrical surfaces

A maximum film thickness of about 440 nm is found at S = -165 % 4 Discussion The film distributions shown in Figures 1 and 2 are really different from the observations made by Gohar et al 1) that are known to be representative of film thickness shape occurring in EHD circular contacts

The measurement of lubricant-lm thickness using ultrasound 959 ball bearing raceway focused ultrasonic transducer lubricant film I F B1 B2 Figure 1 Schematic of an ultrasonic beam incident on a lubricated contact either side of the lubricant represents the bearing elements such as the bush and shaft in a journal bearing or the ball and

Apr 18 2007Film thickness measurements of Elastohydrodynamic (EHD) lubricated contacts are important to evaluate the lubrication regime One of the most used methods of film thickness in-vestigation is optical interferometry This method has been successfully applied to EHL contacts since the 1960s and is particularly suitable for determining also the

A ball-on-disc-type apparatus was used for measuring oil film thickness in EHD contacts A poly-α-olefin (viscosity: 30 mm2/s at 40 C) was used as a test lubricant The ball (diameter: 25 4 mm) was made of 52100 steel The disc (diameter: 100 mm thickness: 10 mm) was made of BK7 glass A Cr film and an ITO (indium tin oxide) film were coated on

CAPACITANCES AND LUBRICANT FILM THICKNESSES OF

To determine the effect of inlet and outlet zone of the EHD-contact the ratio between the calculated Hertzian capacitance and the measured capacitance is plotted over the calculated film-thickness (Figure 5 left) In this diagram different lubricants viscosity and speeds were used

Film thickness in a ball-on-disc contact lubricated with greases bleed oils and base oils T Cousseau M Bjorling B Grac-a A Campos J Seabra R Larsson ABSTRACT Three different lubricating greases and their bleed and base oils were compared in terms of film thickness in a ball-on-disc test rig through optical interferometry

The effects of artificially-produced dents and grooves on the elastohydrodynamic (EHD) film thickness profile in a sliding point contact are investigated by means of optical interferometry The defects formed on the surface of a highly polished ball are held stationary at various locations within and in the vicinity of the contact region

Apr 18 2007Film thickness measurements of Elastohydrodynamic (EHD) lubricated contacts are important to evaluate the lubrication regime One of the most used methods of film thickness in-vestigation is optical interferometry This method has been successfully applied to EHL contacts since the 1960s and is particularly suitable for determining also the

were interested in finding methods for measuring the lubricant film thickness in elastohydrodynamic conditions One of the most versatile and widely used techniques for measuring lubricant film thickness in EHD contacts is the optical interferometry method Apart from numerous advantages this

Jan 31 2006An oil-film thickness monitoring system capable of providing an early warning of lubrication failure in rolling element bearings has been developed The system is used to measure the lubricant-film thickness in a conventional deep groove ball bearing (shaft diameter 80 mm ball diameter 12 7 mm) The measurement system comprises a 50 MHz broadband ultrasonic focused transducer

Nov 12 2018Findings Measurement and calculation of oil film thickness in a ball bearing are carried out under various rotating speeds and external loads By comparing the calculated capacitances with measured results it can be concluded that the calculated results obtained by the amended film thickness formula are much closer to the test findings than the classical computed values according

9 3 EHL Film Thickness Oil 202 9 4 EHD Film Thickness Grease 205 9 5 Starvation 212 9 6 Spin 225 10 Film Thickness in Grease Lubricated Rolling Bearings 227 10 1 Thin Layer Flow on Bearing Surfaces 228 10 2 Starved EHL for Rolling Bearings 234 10 3 Cage Clearance and Film Thickness 239 10 4 Full Bearing Film Thickness 241 11 Grease

An oil-film thickness monitoring system capable of providing an early warning of lubrication failure in rolling element bearings has been developed The system is used to measure the lubricant-film thickness in a conventional deep groove ball bearing (shaft diameter 80 mm ball diameter 12 7 mm) The measurement system comprises a 50 MHz broadband ultrasonic focused transducer mounted