Discussion: “Optical Measurement of Oil Film Thickness Between Rollers” (Willis, T., and Seth, B., 1977, ASME J. Lubr. Technol., 99, pp. 290–293)

1977 ◽  
Vol 99 (2) ◽  
pp. 294-294
Author(s):  
J. W. Kannel
Keyword(s):  
Film Thickness ◽  
Optical Measurement ◽  
Oil Film

Optical Measurement of EHL Film under Oscillating Needle Roller Contacts

2015 ◽  
Vol 642 ◽  
pp. 270-274
Author(s):  
Xue Jin Shen ◽  
Zhen Min Song ◽  
Xiao Yang Chen
Keyword(s):  
Film Thickness ◽  
Working Conditions ◽  
Applied Load ◽  
Optical Measurement ◽  
Rotation Velocity ◽  
Optical Interferometry ◽  
Oil Film ◽  
Pure Rolling ◽  
Rectangular Glass

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 obtained and compared each other. It is found the side constrictions are always the most severe and they are strongly speeds and loads dependence.

Optical Measurement of Oil Film Thickness Between Rollers

1977 ◽  
Vol 99 (2) ◽  
pp. 290-293
Author(s):  
T. Willis ◽  
B. Seth
Keyword(s):  
Laser Beam ◽  
Film Thickness ◽  
Optical Measurement ◽  
Viscosity Index ◽  
Diffraction Method ◽  
High Viscosity ◽  
Oil Film ◽  
Flat Surfaces ◽  
Low Viscosity ◽  
Diffraction Patterns

Previous research has established that the laser beam diffraction method can be used for measurement of film thicknesses between two adjacent flat surfaces. This paper describes further experimentation on this method, where oil film thicknesses between rollers is measured. Calibration curves are obtained between the experimental (set) gap and the gap dimensions which are deduced from the diffraction patterns when the laser beam is passed through the film. These set versus calculated film thickness curves are extremely linear for films which are less than 1 mm depth, the coefficients of correlation with straight lines being close to unity. Data based upon several oils used with 76.2 mm dia rollers are presented and empirical equations established. These equations allow the researcher to obtain the film thickness between the rollers in terms of oil properties (density, viscosity and refractive index) and the geometry of the light beam (wavelength, distance from oil film to diffraction screen, and diffraction pattern bandwidth). The empirical constants in the equations for film thickness appear to apply to specific oil types, and remain the same for each family or group of oil used. The groups used here were SAE 10 through 40, low viscosity index and high viscosity index groups. Oil films from 7.62 × 10−3 mm up to 76.2 × 10−3 mm thickness were measured using this method.

The Surface-Roughness of Bearing-Surfaces and its Relation to Oil Film Thickness at Breakdown

1949 ◽  
Vol 161 (1) ◽  
pp. 73-79 ◽  
Author(s):  
A. Cameron
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Hydrodynamic Theory ◽  
Quantitative Relation ◽  
Metal Contact ◽  
Initial Contact ◽  
Frictional Drag ◽  
Average Roughness ◽  
Finished Steel ◽  
Oil Film

In this paper the relation of surface roughness of bearing surfaces to allowable film thickness is studied quantitatively with a simple Michell pad apparatus. The pads used were faced with white metal and ran against mild steel collars. The lubricants studied were water, soap solution, paraffin, and light oil. There was little difference in the frictional behaviour of any of the lubricants, except that the aqueous lubricants would not run with very finely finished steel surfaces. The onset of metal to metal contact was detected by an increase in the frictional drag, and also by the change in electrical conductivity between the pad and collar—an extremely sensitive method. The paper shows that there is, at any rate for this system, a quantitative relation between the total surface roughness of the rubbing surfaces and the calculated oil film thickness both at the initial metal to metal contact and seizure. Initial contact occurs when the outlet film thickness, calculated from normal hydrodynamic theory, falls to three times the maximum surface roughness and seizure occurs when it is double the average roughness.

Influence of Surface Waviness on the Thermal Elastohydrodynamic Lubrication of an Eccentric-Tappet Pair

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
J. Wang ◽  
C. H. Venner ◽  
A. A. Lubrecht
Keyword(s):  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Surface Waviness ◽  
Film Pressure ◽  
Oil Film ◽  
Working Cycle ◽  
Temperature Oscillations ◽  
Minimum Film Thickness ◽  
Traction Coefficient ◽  
Oil Film Pressure

The effect of single-sided and double-sided harmonic surface waviness on the film thickness, pressure, and temperature oscillations in an elastohydrodynamically lubricated eccentric-tappet pair has been investigated in relation to the eccentricity and the waviness wavelength. The results show that, during one working cycle, the waviness causes significant fluctuations of the oil film, pressure, and temperature, as well as a reduction in minimum film thickness. Smaller wavelength causes more dramatic variations in oil film. The fluctuations of the pressure, film thickness, temperature, and traction coefficient caused by double-sided waviness are nearly the same compared with the single-sided waviness, but the variations are less intense.

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