STUDY OF GREASE BEHAVIOUR IN A STARVED ELASTOHYDRODYNAMICALLY LUBRICATED CONTACT

 MM (Modern Machinery) Science Journal, June 2014

DOI: 10.17973/MMSJ.2014_06_201405

Petr Svoboda, David Kostal, Jiri Kunak, Ivan Krupka

BUT, Faculty of Mechanical Engineering, Institute of Machine and Indurstrial Design, Brno, Czech Republic 

e-mail: svoboda.pe@fme.vutbr.cz

Abstract

 

This paper is an experimental study of grease lubrication in a starved elastohydrodynamic lubricated (EHL) contact. Lubricating film thickness is measured with tribological experimental device ball-on-disc using optical interferometry and high speed camera. The lubricants used were commercial greases with a various kinematic viscosities, additives and thickeners formulated for low and high-speed applications. The experiment is aimed at a comparison of results acquired by ball-on-disc device and full scale axial bearing. In addition, this paper also investigates the influence of number of the rolling elements (overrolling time) on the resulting film thickness. Experiments confirm the presence of replenishment mechanism caused by relative motion of the surfaces, which generates base oil flow into the inlet of the contact.

 
Keywords: grease, starvation, EHD lubrication

 
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CONTEMPORARY FORMS OF PRESENTATION OF RESEARCH AND DEVELOPMENT MARKETING IN THE CZECH REPUBLIC

 MM (Modern Machinery) Science Journal, June 2014

DOI: 10.17973/MMSJ.2014_06_201406

Jiri Vaclavik

TUL, Faculty of Economics, Liberec, Czech Republic

e-mail:jiri.vaclavik@tul.cz

Abstract

The aim of this popularizing scientific article is to briefly describe the utilization and presentation forms of the research and development marketing that are used in the Czech Republic, especially the elements of marketing research, marketing mix and marketing communication in this area. Research and development and related innovations are an integral part of the innovation process and are one of the most important factors for ensuring the competiveness of individual entrepreneurs and as well the whole countries. Therefore a growing importance is being paid to the support of research and development and to the subsequent popularization and commercialization of the achieved results from the field of science and research in advanced countries. The article also mentions the forms of support funding of research and development in the Czech Republic and international comparison of expenditures on R&D.

Keywords: research and development, innovation, marketing research, marketing mix, marketing communication, marketing tools, popularization, commercialization, R&D expenditures

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ON THE COMPARISON OF CONTACT AND NON-CONTACT EVALUATIONS OF A MACHINED SURFACE

MM (Modern Machinery) Science Journal, June 2014

Miroslav Piska, Jitka Metelkova

BUT, Faculty of Mechanical Engineering, Institute of Manufacturing Technology, Brno, Czech Republic

e-mail: piska@fme.vutbr.cz, jitka.metelkova@email.cz

Abstract

Surface integrity of machined parts plays a crucial role in their use, efficiency, comfort and safety. The trend of more effective and low-consumption products forces the producers to reduce weight and dimensions of the industrial parts so the requirements on the machined surface quality evaluation is more important from many aspects. The booming trend in optical non-contact techniques seems to be a serious challenge to the traditional tactile methods. The paper deals with selected contact and non-contact evaluation methods of machined surface (Form Talysurf Intra, Taylor Hobson and IFM G4, Alicona) and relations between profile and 3Dsurface parameters when finishing face turning of AlCu4MgSi in a variety of feed rates. A good correlation for many amplitude and functional surface parameters has been found. Nevertheless, the paper reveals a big power of the optical focus variation technique for quality and functional predictions assessments.

 
Keywords: surface roughness, surface metrology, stylus measurement, 3D optical methods, comparative study, statistical analysis
 
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