Volume 42, No 1, 2020, Pages 102-114

Download full text in PDF

Replenishment Differences in EHL Contact Lubricated by New and In-bearings-aged Grease


M. Navratil , D. Kostal , I. Krupka , M. Hartl

DOI: 10.24874/ti.2020.42.01.10

Received: 22 August 2019
Revised: 01 November 2019
Accepted: 12 December 2019
Published: 15 March 2020


In-contact replenishment differences between new and aged grease are studied using ball-on-disc optical fluorescence. Three different greases were aged in rolling bearings for 30 50 % of their predicted life. A considerable effort is focused on fluorescence calibration, so that differences in lubricant volume can be quantified. No changes in replenishment between new and aged samples were found in one grease. The other two greases were contaminated by metal particles and iron oxide powder. Grease fluorescence was quenched by contaminants and linear relation between intensity values and film thickness did not apply for samples with heaviest contamination. Nevertheless, strong link between the degree of contamination and lubricant replenishment was found.


Grease lubrication, Replenishment, Contamination, Optical fluorescence

Latest issue


Volume 46
Number 1
March 2024

Crossref logo


TiI news RSS 2.0

Table of contents