Analysis of Film Thickness Effect in Slow-Speed Lightly-Loaded Elastrohydrodynamic Contacts. Part III. Experimental Measurement of Lubricant Film Thickness.

1977 ◽  
Author(s):  
SOUTHWEST RESEARCH INST SAN ANTONIO TEX
Keyword(s):  
Film Thickness ◽  
Experimental Measurement ◽  
Lubricant Film ◽  
Thickness Effect ◽  
Lubricant Film Thickness ◽  
Slow Speed

The Influence of Lubricant Film Thickness on Friction Coefficients During Slow Speed Deep Drawing Operations

2002 ◽  
Vol 124 (4) ◽  
pp. 846-851 ◽  
Author(s):  
K. R. Gilmour ◽  
S. Paul ◽  
A. G. Leacock
Keyword(s):  
Film Thickness ◽  
Deep Drawing ◽  
Lubricant Film ◽  
Lubricant Film Thickness ◽  
Slow Speed ◽  
Friction Coefficients ◽  
Initial Application ◽  
The Coefficient Of Friction ◽  
Analysis Of Results ◽  
Topography Data

During some deep drawing operations liquid lubricants are used under the blankholder to reduce friction coefficients. Under the clamping action of the blankholder, lubricants will be squeezed out resulting in a changing film thickness after the initial application of the blankholder load. A relationship between kinetic friction coefficient values and the loading duration of the blankholder can be observed from analysis of results recorded during simulative testing. By using a numerical model to combine empirical measurements, friction coefficients during boundary lubrication, lubricant film thickness with sheet surface topography data, it can be shown that the coefficient of friction can reliably be predicted for a given loading duration.

Study of Direct Measuring of Lubricant Condition in Rolling Element Bearings With Microcomputer Technique

1990 ◽  
Vol 112 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Dongchu Zhao
Keyword(s):  
Film Thickness ◽  
Strain Gage ◽  
Lubricant Film ◽  
Rolling Element Bearings ◽  
Main Program ◽  
Test Apparatus ◽  
Lubricant Film Thickness ◽  
Rolling Element ◽  
Lubricant Films ◽  
Flow Charts

A method for measuring the lubricant condition with strain gage in rolling element bearings and the instrument used are introduced. In order to illustrate the method and the instrument, the theory of measuring lubricant films in rolling element bearings using strain technique, test apparatus, microcomputer hardware as well as software, flow charts for the main program and subprograms, are first described in detail. In addition, the lubricant film thickness is measured for several different lubricants and results are compared with theoretical ones. It is demonstrated that using the method and the instrument introduced in this paper, one can measure the lubricant condition inside bearings very accurately.

scholarly journals An investigation into the oil transport and starvation of piston ring pack

2018 ◽  
Vol 233 (1) ◽  
pp. 112-124 ◽  
Author(s):  
SR Bewsher ◽  
M Mohammadpour ◽  
H Rahnejat ◽  
G Offner ◽  
O Knaus
Keyword(s):  
Film Thickness ◽  
Boundary Conditions ◽  
Piston Ring ◽  
Gasoline Engine ◽  
Reverse Flow ◽  
Lubricant Film ◽  
Total Power ◽  
Lubricant Film Thickness ◽  
Piston Ring Pack ◽  
Ring Pack

In order to accurately predict the lubricant film thickness and generated friction in any tribological contact, it is important to determine appropriate boundary conditions, taking into account the oil availability and extent of starvation. This paper presents a two-dimensional hydrodynamic model of a piston ring pack for prediction of lubricant film thickness, friction and total power loss. The model takes into account starvation caused by reverse flow at the conjunctional inlet wedge, and applied to a ring pack, comprising a compression and scraper ring. Inlet boundaries are calculated for an engine cycle of a four-cylinder, four-stroke gasoline engine operating at 1500 r/min with conditions pertaining to the New European Drive Cycle. The analysis shows the two main sources of starvation: first, due to a physical lack of inlet meniscus and second, due to reverse flow at the inlet wedge significantly affecting the prevailing conditions from the generally assumed idealised boundary conditions. Such an approach has not hitherto been reported in literature.

Instrumented Engine Bearings for Lubricant Film Thickness Measurement

MTZ worldwide ◽  
2021 ◽  
Vol 83 (1) ◽  
pp. 28-37
Author(s):  
Henry Brunskill ◽  
Andrew Hunter ◽  
Hosung Nam ◽  
Junsik Park
Keyword(s):  
Film Thickness ◽  
Thickness Measurement ◽  
Lubricant Film ◽  
Lubricant Film Thickness ◽  
Film Thickness Measurement

Gear Tribology and Lubrication

2005 ◽  
pp. 19-38
Keyword(s):  
Film Thickness ◽  
Case History ◽  
Failure Modes ◽  
Gear Tooth ◽  
Lubricant Film ◽  
Flash Temperature ◽  
Lubricant Film Thickness ◽  
Film Lubrication

Abstract This chapter reviews the knowledge of the field of gear tribology and is intended for both gear designers and gear operators. Gear tooth failure modes are discussed with emphasis on lubrication-related failures. The chapter is concerned with gear tooth failures that are influenced by friction, lubrication, and wear. Equations for calculating lubricant film thickness, which determines whether the gears operate in the boundary, elastohydrodynamic, or full-film lubrication range, are given. Also, given is an equation for Blok's flash temperature, which is used for predicting the risk of scuffing. In addition, recommendations for lubricant selection, viscosity, and method of application are discussed. The chapter discusses in greater detail the applications of oil lubricant. Finally, a case history demonstrates how the tribological principles discussed in the chapter can be applied practically to avoid gear failure.

scholarly journals The Impact of Lubricant Film Thickness and Ball Bearings Failures

Lubricants ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 48 ◽  
Author(s):  
Matthew David Marko
Keyword(s):  
Film Thickness ◽  
Fatigue Failure ◽  
Failure Mechanisms ◽  
Roller Bearing ◽  
Lubricant Film ◽  
Theoretical Formula ◽  
Empirical Equations ◽  
Ball Bearings ◽  
Lubricant Film Thickness ◽  
The Impact

An effort was made to find a relationship between the lubricant thickness at the point of contact of rolling element ball bearings, and empirical equations to predict the life for bearings under constant motion. Two independent failure mechanisms were considered, fatigue failure and lubricant failure resulting in seizing of the roller bearing. A theoretical formula for both methods was established for the combined probability of failure using both failure mechanisms. Fatigue failure was modeled with the empirical equations of Lundberg and Palmgren and standardized in DIN/ISO281. The seizure failure, which this effort sought to investigate, was predicted using Greenwood and Williamson’s theories on surface roughness and asperities during lubricated contact. These two mechanisms were combined, and compared to predicted cycle lives of commercial roller bearing, and a clear correlation was demonstrated. This effort demonstrated that the Greenwood–Williams theories on the relative height of asperities versus lubricant film thickness can be used to predict the probability of a lubricant failure resulting in a roller bearing seizing during use.

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