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.

Elastohydrodynamic Lubrication of a Line Contact

1974 ◽  
Vol 188 (1) ◽  
pp. 221-238 ◽  
Author(s):  
D. G. Wymer ◽  
A. Cameron
Keyword(s):  
Film Thickness ◽  
Central Region ◽  
Glass Plate ◽  
Elastohydrodynamic Lubrication ◽  
Optical Interferometry ◽  
Optical Measurements ◽  
Line Contact ◽  
Electrical Measurements ◽  
Oil Film ◽  
Pure Rolling

In Part 1, optical interferometry is used to study an elastohydrodynamically lubricated line contact between a taper roller and a glass plate under pure rolling conditions. The results give detailed information on film profiles and show the effects of end blending, lubricant starvation, deep scratches and static oil entrapments. In Part 2, oil film thicknesses in an elastohydrodynamic line contact are measured using optical interferometry and compared with theory. Two empirical formulae are derived for film thickness in the central region and at the exit constriction. In addition to the optical measurements, electrical measurements (resistance and capacitance) are made simultaneously, enabling a direct comparison to be made.

Oil Film Thickness in Lightly-Loaded Roller Bearings

1974 ◽  
Vol 16 (6) ◽  
pp. 386-390 ◽  
Author(s):  
H. Bahadoran ◽  
R. Gohar
Keyword(s):  
Film Thickness ◽  
Similar Condition ◽  
Thrust Bearing ◽  
Roller Bearing ◽  
Optical Interferometry ◽  
Oil Film ◽  
Roller Bearings ◽  
Tapered Roller

The effects of speed, load and roller geometry on the oil film thickness and shape in a complete roller bearing are demonstrated experimentally by means of optical interferometry. At quite moderate roller speeds, increase of film thickness becomes inhibited. This effect is attributed to a truncated inlet meniscus, a similar condition having been observed elsewhere with a ball-and-plate machine and with a model of a tapered-roller thrust bearing.

Elastohydrodynamic Behavior of Rolling Elliptical Contacts: Part II: Oil Film Thickness and Contact Profile

1985 ◽  
Vol 107 (3) ◽  
pp. 352-357 ◽  
Author(s):  
M. O. A. Mokhtar ◽  
A. A. Abdel-Ghany
Keyword(s):  
Film Thickness ◽  
Contact Zone ◽  
Circular Disk ◽  
Rolling Contact ◽  
Thickness Variation ◽  
Relative Speed ◽  
Oil Film ◽  
Sliding Motion ◽  
Pure Rolling ◽  
Experimental Findings

A spherically crowned circular disk in contact with a mating plain cylindrical one has been used in a two disk machine to conduct elastohydrodynamic (EHD) investigations with the contact zone describing elliptical shape. The oil film thickness variation has been accurately measured and herein presented under several contact situations with disks running with either pure rolling or combined rolling and sliding motion. Results confirmed that the introduction of a percentage slip over a rolling contact by either changing disks relative speed or skewing disks axes relative to each other, would affect the resultant oil film thickness by reducing it. However, the contact profile retained its shape with a mean oil film passage followed by a reduction at the trailing exit end. Compared with previous EHD theoretical and experimental findings, the present results come in line with previous predictions and confirm the importance of adopting thermal solutions in solving EHD situations.

Effects of Asperities in Elastohydrodynamic Lubrication

1980 ◽  
Vol 102 (3) ◽  
pp. 374-378 ◽  
Author(s):  
M. Kaneta ◽  
A. Cameron
Keyword(s):  
Film Thickness ◽  
Glass Plate ◽  
Three Dimensional ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Critical Value ◽  
Optical Interferometry ◽  
Asperity Height ◽  
Height Ratio ◽  
Pure Rolling

Optical interferometry was used to study rough surfaces under lubricated point contact. Three dimensional “asperities” of chromium were sputtered onto a steel ball which was run against a smooth glass plate under both rolling and sliding. The experimental results were compared with the various published theories. The film thicknesses found in sliding are different from those observed in pure rolling, which are nearly equal to the theoretical values. Film thickness collapse occurred when the central film thickness/half asperity height ratio (λ ratio) reached a critical value.

Thermal EHL Analyses of Point Contacts With Surface Roughness

2005 ◽  
Author(s):  
J. Wang ◽  
P. Yang ◽  
M. Kaneta
Keyword(s):  
Surface Roughness ◽  
High Temperature ◽  
Film Thickness ◽  
Temperature Rise ◽  
Point Contacts ◽  
Oil Film ◽  
Sliding Motion ◽  
Pure Rolling ◽  
Thermal Ehl ◽  
High Temperature Rise

The Newtonian thermal EHL analyses of point contacts with two-sided surface roughness have been performed under pure rolling, sliding/rolling and simple sliding conditions. Thermal results are compared with isothermal ones. It has been found that the sliding motion produces high temperature rise and reduces the film thickness greatly. The influence of amplitude and wavelength of the surface roughness on variation of tribo-characteristics of oil film is also discussed.

Inlet Shear Heating in Elastohydrodynamic Lubrication

1973 ◽  
Vol 95 (4) ◽  
pp. 417-423 ◽  
Author(s):  
J. A. Greenwood ◽  
J. J. Kauzlarich
Keyword(s):  
Shear Rate ◽  
Theoretical Analysis ◽  
Film Thickness ◽  
Temperature Rise ◽  
Thermal Effects ◽  
Elastohydrodynamic Lubrication ◽  
Oil Film ◽  
Comparison With Experiment ◽  
Pure Rolling ◽  
Shear Heating

In EHL, the oil film thickness of rollers is controlled by the rate at which the oil is drawn into the conjunction of the disks by the moving surfaces of the rollers. The theory often assumes isothermal conditions in the inlet although it can be shown that the maximum shear rate often exceeds 106 sec−1, even in pure rolling. A theoretical analysis is presented for the oil temperature rise in the inlet of rollers, and the result is applied to predict the consequent film thickness. It is found that thermal effects on film thickness are only negligible at low rolling speeds. A comparison with experiment supports the conclusion that the thinning of the film thickness below that predicted by isothermal theory is substantially explained by inlet shear heating of the lubricant.

The dynamic simulation and experiment of bearing capacity of multi oil cushion static bearing with double rectangular cavities

2019 ◽  
Vol 71 (9) ◽  
pp. 1072-1079
Author(s):  
Yanqin Zhang ◽  
Jichang Sun ◽  
Pengrui Kong ◽  
Xiangbin Kong ◽  
Xiaodong Yu
Keyword(s):  
Film Thickness ◽  
Bearing Capacity ◽  
Dynamic Simulation ◽  
Working Conditions ◽  
Operating Conditions ◽  
Dynamic Mesh ◽  
Maximum Pressure ◽  
Inlet Flow ◽  
Content Type ◽  
Oil Film

Purpose The purpose of the paper is to analyze the bearing capacity of hydrostatic bearing during the change of film thickness under different working conditions and to improve the processing efficiency and precision of equipment. Design/methodology/approach In this study, Q1-205 double rectangular cavity hydrostatic thrust bearing is selected as the research object. The dynamic mesh method and ANSYS/FLUENT software are used to simulate the curves of oil film thickness and oil pressure under different operating conditions. Finally, the change of pressure in the oil cavity at different operating speeds under a certain inlet flow rate was tested through design experiments. Findings When the film thickness was thick, the maximum pressure in the oil cavity at different inlet velocities showed little difference. With a larger inlet flow, the maximum pressure in the oil cavity was higher. The pressure at the edge of the oil seal was linearly distributed. The oil pressure in the downstream side was greater than that in the counter flow side. When the working pressure was low, the pressure in the oil cavity slightly decreased with the increase of working speed. Moreover, the pressure loss at high speed was considerable. Originality/value Based on the lubrication theory, the mathematical model of the bearing oil film was set up. The bearing capacity equation of the hydrostatic cavity was derived. The double-rectangular-annular hydrostatic guides studied in this paper have not been reported in previous research literature and the method of dynamic mesh dynamic simulation of variable viscosity is seldom studied before. The bearing characteristics and the change of oil film thickness under different working conditions have been studied systematically and comprehensively. The theoretical analysis results are basically consistent with the experimental results.

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