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Evaluation of machine elements surface topography by optical profilometer
Vrána, Jakub ; Křupka, Ivan (referee) ; Šperka, Petr (advisor)
This thesis deals with the issue of surface texture topography of engineering parts. Research provides general view of surface texture topography evaluation and puts the aforementioned into the context of international standards. In the practical part of this thesis, an experiment is implemented. With help of optical interferometer, parameters are measured and their robustness is evaluated. In the conclusion part of this thesis, acquired information are evaluated and resumed.
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An overview of oils and their engineering applications
Kozák, Ondřej ; Frýza, Josef (referee) ; Šperka, Petr (advisor)
This Bachelor´s thesis deals with an overview of current state of knowledge of lubricating oils and their engineering applications. It includes characteristic and division of oils by manufacturing method and division of these oils by chemical structure. Basic compounds of oils including most used types of additives are mentioned and described. Next part of the thesis focuses on lubricant properties. Final part includes resume of applications in which the listed oils are applied and required properties for each type of application are mentioned.
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Wear regimes of aluminium alloys
Slivka, Václav ; Zapletal, Tomáš (referee) ; Šperka, Petr (advisor)
This thesis deals with the research of the wear regimes of the selected aluminium alloy in the conditions of dry friction. The aim of this work is the evaluation of the measure of an abrasive and adhesive wear of this alloy. This evaluation is made from the experiments which are made on the base of the knowledge of the research study. The dependence of the wear on the sliding speed and load, the friction on the sliding speed and load and the dependence of the normalised pressure on the normalised speed, so called the map of wear, are given on the base of the results of the measure.
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Lubrication of plastic gears
Poledník, Radim ; Vimmr, Jan (referee) ; Šperka, Petr (advisor)
The purpose of this diploma thesis is to describe the influence of input parameters (rolling speed, load, temperature, dynamic viscosity and pressure coefficient of the lubricant) on film thickness in point and elliptical contacts using optical interferometry. Regression based film thickness formula has been obtained using universal form of non-dimensional parameters of entrainment speed U, load W and material G. Equations were also complemented by the function of ellipticity k. New regression formulas for central and minimum film thickness have been compared with existing EHL thickness equations. These film thickness measurement and new regression formulas have applicability to our understanding of the performance and more effective design of lubricated gears from polymeric materials.
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The effect of texture geometry on friction and lubricating film formation in radial journal bearing
Katrincová, Tereza ; Čermák, Jan (referee) ; Šperka, Petr (advisor)
The aim of this diploma thesis is to find out how the geometric parameters of circular textures affect the friction and lubrication in a conformal contact. The configuration of a partial, radial, hydrodynamic bearing was investigated on a modified block on-ring device, where the block was replaced by a sapphire section. The device allows simultaneous measurement of friction and optical observation of processes in contact. The light induced fluorescence method was used for the measurement of film thickness. None of the studied texture combinations had a positive effect on the transition from hydrodynamic mode to mixed lubrication mode. Textures in the narrow band of the combination of diameter and depth have a positive effect, outside of them negative effect of texture on friction and film thickness was observed.
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Design of the triaxial vibration positioner for removing residual powder from the metal prints
Šváb, Čeněk ; Šperka, Petr (referee) ; Suchý, Jan (advisor)
This bachelor's thesis is focused on the construction of a two-axis positioner, designed for removing dust out of parts created by a 3D printer SLM 280HL. The aim of this work is to design the construction of a two-axis positioner with an integrated vibration drive. The first part deals with the description of the types of manipulators and vibration motors. Based on the obtained information, the construction issues are outlined and various design tips are proposed to address it. The most suitable design is then selected and elaborated in detail. The output is a functional design solution of a two-axis positioner with an implemented vibration motor and the ability to run in a dusty environment.
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Design of reciprocal module fixture for wear and friction measurements in tribometer
Zeman, Petr ; Šperka, Petr (referee) ; Dočkal, Kryštof (advisor)
The thesis deals with design of a clamping fixture for fastening surface samples for the reciprocating drive of the tribometer. The fixture is designed to compensate for shape deviations of the samples by tilting in two axes in a small range. The objective has been fulfilled, the tilting mechanism is achieved by rotating the spherical surface. The fixture is sufficiently rigid. It has been achieved of better user experience and repeatability of clamping. The paper contains an overview of commercially available clamping methods, their evaluation and description of the construction of the newly designed device, which simplifies the clamping of uniquely shaped samples for the reciprocating drive of the UMT TriboLab tribometer.
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Design of apparatus for testing of bearings
Sovadina, František ; Šperka, Petr (referee) ; Svoboda, Petr (advisor)
In this bachelor thesis an analysis of used test devices for durability of the rolling bearing was performed. This analysis then serves as an inspiration for the reconstruction of the existing bearing test facility at FME BUT. Three conceptual designs have been developed and, after consideration of all aspects, drawing documentation for the final variant has been produced. Its design will lead to space saving in the laboratory and easier handling of test equipment in durability tests.
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In-situ Study of Surface Topography Changes in Elastohydrodynamic Contact
Šperka, Petr ; Dzimko, Marián (referee) ; Návrat, Tomáš (referee) ; Dobeš, Petr (referee) ; Hartl, Martin (advisor)
This dissertation thesis deals with elastohydrodynamic lubrication (EHL) of surfaces with real roughness. Systematic study of surface harmonic components behaviour, during their passage of the EHL contact, by other authors led to retrieval of a uniform principle according which individual harmonic components deform inside the contact. Although the amplitude attenuation model can provide rapid tool for more accurate surface assessment in design process it has not been validated on real surfaces till now. The thesis represents pioneering work on quantitative analysis of real surfaces EHD measurements. It contains original and new results with real and model roughness features that in many cases confirm theoretical expectations. Deeper understanding of surface roughness behaviour inside EHL contact, which is typical for machine parts like bearings, gears, cams etc., can help to improve design process of the components and ultimately enable machines and equipment to work with lower energy requirements and higher durability.
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