Lubricant film thickness mapping using a capacitance technique on magnetic thin-film rigid disks

1998 ◽  
Vol 69 (9) ◽  
pp. 3339-3349 ◽  
Author(s):  
Chris D. Hahm ◽  
Bharat Bhushan
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Lubricant Film ◽  
Magnetic Thin Film ◽  
Lubricant Film Thickness ◽  
Rigid Disks

Interaction of Asperities on Opposing Surfaces in Thin Film, Mixed Elastohydrodynamic Lubrication

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Jian W. Choo ◽  
Andrew V. Olver ◽  
Hugh A. Spikes ◽  
Marie-Laure Dumont ◽  
Eustathios Ioannides
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Experimental Method ◽  
Elastohydrodynamic Lubrication ◽  
Lubricant Film ◽  
New Technique ◽  
Lubricant Film Thickness ◽  
Transverse Ridge ◽  
Film Distribution ◽  
Direct Measurements

A novel experimental method has been developed to investigate how model asperities, on opposing surfaces in an elastohydrodynamic (EHD) contact, interact to influence the lubricant film distribution. This technique allows direct measurements of lubricant film thickness during asperity-asperity collision. A surface having a single transverse ridge asperity was rubbed against a second surface having three different roughness features, a transverse ridge, multiple transverse ridges, and an array of hemispherical bumps to study the resultant micro-EHD films. This work reveals how the film thickness is greatly reduced when the peaks of opposing asperities coincide, and how asperities can combine to cause a larger volume of lubricant to be entrapped at their leading edges. The new technique described shows considerable promise for the study of mixed lubrication.

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.

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