On the Relation between Friction Increase and Grease Thickener Entraining on a Border of Mixed EHL Lubrication

On the Relation between Friction Increase and Grease Thickener Entraining on a Border of Mixed EHL Lubrication

This paper deals with an experimental study of film thickness and friction of commercial-grade grease and its base oil in a highly loaded contact. In-situ measurements were conducted for two surface textures on a ball-on-disc optical tribometer at the border of mixed lubrication. At high speeds, the...

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Bibliographic Details
Main Authors: Tomas Zapletal, Petr Sperka, Ivan Krupka, Martin Hartl
Format: Article
Language:English
Published: MDPI AG 2020-01-01
Series:Lubricants
Subjects:
film thickness
friction
grease
base oil
ehl
Online Access:https://www.mdpi.com/2075-4442/8/2/12
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spelling doaj-b169855d4a964591969d34528b9d39a02020-11-25T02:20:44ZengMDPI AGLubricants2075-44422020-01-01821210.3390/lubricants8020012lubricants8020012On the Relation between Friction Increase and Grease Thickener Entraining on a Border of Mixed EHL LubricationTomas Zapletal0Petr Sperka1Ivan Krupka2Martin Hartl3Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 616 69 Brno, Czech RepublicFaculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 616 69 Brno, Czech RepublicFaculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 616 69 Brno, Czech RepublicFaculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 616 69 Brno, Czech RepublicThis paper deals with an experimental study of film thickness and friction of commercial-grade grease and its base oil in a highly loaded contact. In-situ measurements were conducted for two surface textures on a ball-on-disc optical tribometer at the border of mixed lubrication. At high speeds, the film thickness and the friction of grease correspond with the base oil, while, the thickener enters the contact area and locally affects the film thickness and friction at low speeds. It was found out that the thickener starts to enter the contact area approximately at the same speed when the base oil friction increases on Stribeck curve but without direct solid to solid contact. It indicates that both effects can have the same origin. Change of lubricant flow in contact inlet area was discussed as a possible explanation.https://www.mdpi.com/2075-4442/8/2/12film thicknessfrictiongreasebase oilehl
collection DOAJ
language English
format Article
sources DOAJ
author Tomas Zapletal
Petr Sperka
Ivan Krupka
Martin Hartl
spellingShingle Tomas Zapletal
Petr Sperka
Ivan Krupka
Martin Hartl
On the Relation between Friction Increase and Grease Thickener Entraining on a Border of Mixed EHL Lubrication
Lubricants
film thickness
friction
grease
base oil
ehl
author_facet Tomas Zapletal
Petr Sperka
Ivan Krupka
Martin Hartl
author_sort Tomas Zapletal
title On the Relation between Friction Increase and Grease Thickener Entraining on a Border of Mixed EHL Lubrication
title_short On the Relation between Friction Increase and Grease Thickener Entraining on a Border of Mixed EHL Lubrication
title_full On the Relation between Friction Increase and Grease Thickener Entraining on a Border of Mixed EHL Lubrication
title_fullStr On the Relation between Friction Increase and Grease Thickener Entraining on a Border of Mixed EHL Lubrication
title_full_unstemmed On the Relation between Friction Increase and Grease Thickener Entraining on a Border of Mixed EHL Lubrication
title_sort on the relation between friction increase and grease thickener entraining on a border of mixed ehl lubrication
publisher MDPI AG
series Lubricants
issn 2075-4442
publishDate 2020-01-01
description This paper deals with an experimental study of film thickness and friction of commercial-grade grease and its base oil in a highly loaded contact. In-situ measurements were conducted for two surface textures on a ball-on-disc optical tribometer at the border of mixed lubrication. At high speeds, the film thickness and the friction of grease correspond with the base oil, while, the thickener enters the contact area and locally affects the film thickness and friction at low speeds. It was found out that the thickener starts to enter the contact area approximately at the same speed when the base oil friction increases on Stribeck curve but without direct solid to solid contact. It indicates that both effects can have the same origin. Change of lubricant flow in contact inlet area was discussed as a possible explanation.
topic film thickness
friction
grease
base oil
ehl
url https://www.mdpi.com/2075-4442/8/2/12
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AT petrsperka ontherelationbetweenfrictionincreaseandgreasethickenerentrainingonaborderofmixedehllubrication
AT ivankrupka ontherelationbetweenfrictionincreaseandgreasethickenerentrainingonaborderofmixedehllubrication
AT martinhartl ontherelationbetweenfrictionincreaseandgreasethickenerentrainingonaborderofmixedehllubrication
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