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Off-board systems for top-of-rail lubrication
Málek, Jan ; Kvarda, Daniel (referee) ; Galas, Radovan (advisor)
This bachelor’s thesis is focused on rail off-board lubrication system. The main part of this thesis is explaining of function and design few certain lubrication systems. In this thesis are explained aspects of wheel-rail contact, such as types and parts of rail, adhesion, slip, creep–traction diagram. Another part of this thesis is description of few certain lubrication system for top of rail and gauge face application. In this thesis are explained product of major companies of friction management industries such as SKF-Lincoln, Whitmore, Loram. Additional part of this thesis speaks about usage and development of this devices in Czech Republic. Output of this thesis is conclusion about advantages and disadvantages these certain devices.
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Production of support by forming
Palán, Robert ; Novotný, Karel (referee) ; Kopřiva, Miloslav (advisor)
PALÁN Robert, Production of support forming.A graduation thesis of master´s studies, Mechanical engineering, Department M2307 Metal forging technology, Specialization 02 Forming, Welding, 2. graduate, 2. year, school – year 2007/2008. FSI VUT Brno, ÚST Department of Metal Forging Technology, May 2008, page NO 66, picture NO 36, chart NO 8, suplement NO 12 The graduation thesis, drew up with in the frame of engeneering studies department M2307, submits a concept of a production by forming. A materiál of a forget piece is steel ČSN 12 050, provided as a semi – finished product in a form of a bar 210 mm, lenght 4 000 mm. The particular dimension stocks with be cut from it to forge out a part. Production work is 100 000 pcs. Based on studies of technologies, suitable for producing the part a specific two stage technology of a drop forging was chozen on a vertical forging press LMZ 6 500, with induction heating of the semi – finished product and a product – trim of fin and pellicle or a trimming press LDO 315 A/S. For this alternate all the required calculations are realized of swages and all the necessary machines for the production of are quested enganget part.
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Plain Bearings for CI Tractor Engine
Petr, David ; Ramík, Pavel (referee) ; Dundálek, Radim (advisor)
This thesis deals with the hydrodynamic plain bearings tractor diesel engine. The first part is closer acquainted with the hydrodynamic bearing, its principles and materials used. The next part work deals with the multibody system adams-engine. The main part of this work is to model the crank mechanism and its storage in hydrodynamic bearings in the MBS program and the subsequent simulation under different operating conditions.
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Experimental study of the starved lubrication
Novotný, Antonín ; Čermák, Jan (referee) ; Košťál, David (advisor)
This master’s thesis deals with the experimental study of an elastohydrodynamic contact under conditions of insufficient lubricant supply. Starvation level of this type of the contact may be experimentally determined based on the input position of the meniscus, but this way can’t determine all its levels of starvation. Consequent development in the field of tribology achieved theoretical model that can determine at all levels of starvation depending on the thickness of the lubricant film entering the contact, but it is relatively difficult for experimental verification. The main goal of this work is an experimental study and describes the behavior of elastohydrodynamic contact at an exactly defined thickness of the lubricant film at the contact input. The benefit of this work is a validation of that mentioned theoretical model for base oils and greases made from them, and mutual comparison of their behavior.
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Research of Coatings of Hydrodynamically Lubricated Sliding Bearings for Combustion Engines
Repka, Martin ; Čermák, Roman (referee) ; Petrůj, Jaroslav (referee) ; Havlica, Jaromír (advisor)
Hlavní náplní této dizertační práce je výzkum a vývoj nové povrchové vrstvy pro kluzná ložiska na bázi pevných lubrikantů v polyamid-imidové polymerní matrici se zlepšenými tribologckými vlastnostmi. Podklady pro materiálovou kompozici vzešly z expertízy komerčně dostupného povlaku, respektive jeho povrchovou analýzou v mezných operačních podmínkách. Charakterizace mazného oleje před a po tribotestování společně s detailní povrchovou analýzou dala podmínky pro vznik materiálové formulace. Další část práce se zabývá studiem přípravy a vývojem aplikačního nanášení s přípravou polymerní směsi. Nakonec je popsána studie vlivu sulfidu molybdeničitého a grafitu, jakožto pevných lubrikantů pro zlepšení třecích vlastností a hydroxidu vápenatého pro potenciální zpepšení otěruvzdornosti výsledného povrchu pro palikaci kluzných ložisek.
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Experimental Study of the Lubricant Film under Starved Conditions
Košťál, David ; Čermák, Jan (referee) ; Dzimko, Marián (referee) ; Ali, Fadi (referee) ; Křupka, Ivan (advisor)
The dissertation thesis deals with an experimental study of an elastohydrodynamic contact under insufficient lubricant supply. Theoretical studies published in this research area focus mainly on the development of theoretical models and there is an insufficient number of experimental studies which validate these models. There are two basic methods of starvation severity control in published theoretical models: by positioning of an inlet meniscus and by setting the thickness of an oil layer in the vicinity of contact inlet. The second method is more suitable when considering a wide range of operating conditions, however it is difficult to ensure experimentally. This thesis presents original experimental results and aims to describe the starvation severity level as a function of the inlet film thickness. Deeper understanding of fundamental processes in starved elastohydrodynamic contacts enables the development of more precise models, better ability of prediction of the starvation and improves the ability to avoid starvation in the early design process of key tribological components.
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Analysis of THR lubrication with the use of fluorescent microscopy
Tkadlec, Tadeáš ; Daniel, Matej (referee) ; Nečas, David (advisor)
This diploma thesis deals with an experimental analysis of lubrication of total hip joint replacement using fluorescence microscopy, focusing on so-called soft bearing pairs. Experiments were realized using a hip joint simulator, which was modified and refined for fluorescence microscopy. The aim of this diploma thesis was to determine the effect of the individual components of the synovial fluid on the lubrication mechanisms. For this purpose, different model fluids were designed to represent the composition of proteins and other synovial fluid constituents to elucidate the effect of albumin, -globulin and hyaluronic acid on the resulting lubrication performance. The experiments were separate into two categories different in type of load, dynamic (representative walking) and combined (representing standing with short walk). The experimental results were time-dependent fluorescence intensity values, representing dimensionless film thickness parameters. The values were recorded on the graphs and supplemented with fluorescence images taken during the characteristic sections of the measurements. The measured data was subsequently confronted with previously published articles. It was found that the dominant constituent responsible form film thickness is albumin, while -globulin and hyaluronic acid forms thin stable layer enhancing adsorption ability of albumin which contributes to increase of film thickness eventually.
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Piston Ring Tribology in Internal Combustion Engines
Orbán, Tomáš ; Maršálek, Ondřej (referee) ; Raffai, Peter (advisor)
The theme of the thesis is tribology of piston rings for internal combustion engines. The work is divided into seven chapters. The first chapter deals with the piston rings, piston rings requirements, describes the main functions of piston rings, types of piston rings, compression rings and oil control rings. Finally, this chapter provides information about the kinematics of piston rings. The second chapter presents the mechanism of friction and lubrication of piston rings, is dedicated to tribology, friction, friction observation history, mechanism of friction and friction suitability. In addition, the work contains information about lubrication, specifically about a lubrication way of internal combustion engines and lubrication regimes. The third chapter deals with hydrodynamic lubrication. The theme of the fourth chapter is boundary lubrication. The fifth chapter provides information about mixed lubrication. Friction in the oil film is the theme of the sixth chapter. Last seventh chapter deals with dry contact friction due to surface roughness contact.
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