A Multi-Wavelength Light Interference Method for the Measurement of Lubricating Film Thickness

A multi-wavelength light interference method for the measurement of lubricating film thickness was proposed for the improvement of convenience and accuracy of monochromatic light interferometry. Through the successive analysis of the hypothetical curves and the revised curves of three-wavelength light interference, the procedures of this method were discussed in detail. Then three-wavelength light interference method was applied to measure the lubricating film thickness of base oil under a specific condition. In comparison with the numerical results of Hamrock-Dowson formula, it was concluded that the multi-wavelength light interference method is applicable for the measurement of lubricating film thickness. With this method, the only requirement is the images which captured in stationary and purposed conditions, and higher measurement accuracy can be achieved.

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Applicability of an Oil Based Calculation Approach for Wear Risk and Wear Lifetime to Grease Lubricated Gear Pairings

Volume 10: 2019 International Power Transmission and Gearing Conference ◽

10.1115/detc2019-97439 ◽

2019 ◽

Author(s):

Benedikt J. Siewerin ◽

Andreas Dobler ◽

Thomas Tobie ◽

Karsten Stahl

Keyword(s):

Film Thickness ◽

Failure Modes ◽

Surface Hardness ◽

Wear Intensity ◽

Experimental Investigations ◽

Limiting Factor ◽

Slow Speed ◽

Base Oil ◽

Wear Rates ◽

Lubricating Film

Abstract Gear pairings often run under very high loads. That can result in different kinds of failure modes limiting their lifetime. Many of the known gear failure modes are tribologically influenced. Especially for gear pairs running with lower circumferential speeds or with different surface hardness, (continuous or slow speed) wear is often the lifetime limiting factor. Slow speed wear appears continuously over a longer period of runtime. In many cases, such applications are lubricated with greases. Since the standardized calculation methods (e.g. ISO 6336) do not cover any determination of wear, one common way to predict the wear lifetime is the calculation method according to Plewe. In the associated Plewe diagram the worn off amount of material is correlated to the minimal lubricant film thickness in the tooth contact. The wear intensity decreases for higher film thicknesses. However, this method has certain limits for greases, because the film thickness of a grease, its bleed oil and the base oil is not necessarily the same. Additionally, the consistency and the flow properties have to be considered, because they influence the lubrication supply mechanism (circulating or channeling). Under certain circumstances channeling could be predominant. Although in theory a grease should build a thicker lubricating film than its base oil, experimental investigations have shown higher wear rates in comparison to oil lubrication.

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Mapping lubricating film thickness, film extent and ring twist for the compression-ring in a firing internal combustion engine

Tribology International ◽

10.1016/j.triboint.2013.10.001 ◽

2014 ◽

Vol 70 ◽

pp. 112-118 ◽

Cited By ~ 10

Author(s):

G. Garcia-Atance Fatjo ◽

E.H. Smith ◽

I. Sherrington

Keyword(s):

Film Thickness ◽

Internal Combustion Engine ◽

Combustion Engine ◽

Internal Combustion ◽

Compression Ring ◽

Lubricating Film ◽

Lubricating Film Thickness

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Determination of thin hydrodynamic lubricating film thickness using dichromatic interferometry

Applied Optics ◽

10.1364/ao.53.006066 ◽

2014 ◽

Vol 53 (26) ◽

pp. 6066 ◽

Cited By ~ 7

Author(s):

L. Guo ◽

P. L. Wong ◽

F. Guo ◽

H. C. Liu

Keyword(s):

Film Thickness ◽

Lubricating Film ◽

Lubricating Film Thickness

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Prediction of transient lubricating film thickness in knee prostheses with compliant layers

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/0954411981533935 ◽

1998 ◽

Vol 212 (3) ◽

pp. 157-164 ◽

Cited By ~ 18

Author(s):

Z M Jin ◽

D Dowson ◽

J Fisher ◽

N Ohtsuki ◽

T Murakami ◽

...

Keyword(s):

Knee Joint ◽

Film Thickness ◽

Elastohydrodynamic Lubrication ◽

Contact Radius ◽

Knee Prostheses ◽

Stroke Length ◽

Additional Advantage ◽

Lubricating Film ◽

Theoretical Predictions ◽

Lubricating Film Thickness

The transient lubricating film thickness in knee prostheses using compliant layers has been predicted under simulated walking conditions based upon the elastohydrodynamic lubrication theory. Qualitative agreement has been found between the present theoretical predictions and the experimental measurements using an electric resistance technique reported earlier. It has been shown that the contact geometry plays an important role in the generation of fluid film lubrication in knee prostheses using compliant layers. The maximum lubricating film thickness is predicted for the maximized contact area of a transverse conjunction where the semi-minor contact radius lies in the direction of entraining. The additional advantage of the transverse contact conjunction is that the possibility of lubricant starvation due to small stroke length can be minimized. All these factors, together with the kinematic requirements in the natural knee joint, should be taken into consideration when designing artificial knee joint replacements.

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