National Repository of Grey Literature 40 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Smart bearings
Junek, Jaroslav ; Polnický, Vojtěch (referee) ; Hartl, Martin (advisor)
This thesis deals with the issue of smart bearing, which can be used to refine and determine the condition of the bearing. Due to its advantageous availability of the cyber-physical system as a suitable apparatus for industrial use. The links and connections within this system are mentioned here. The following is a summary of commercially available smart bearings. It is complemented by patent solutions and scientific studies, which could point to future developments in this area.
Design of the test rig for the observations of the lubricant distribution in the rolling bearing
Okál, Michal ; Hartl, Martin (referee) ; Košťál, David (advisor)
Given diploma thesis deals with the design and realization of a device whose purpose is to simulate real condition in the contact area of deep groove ball bearings. Direct observation of such area was then carried out. Initial part of the thesis addresses principles occurring in ball bearings, such as friction and lubrication and wear mechanisms. Several devices which are commonly used for bearing lubrication studies are then described at the work. Subsequently, author’s solution was introduced with the output of Ball-on-ring device. Ball-on-ring configuration is key feature due to its geometry since it enables to create identical conditions as those which occur in ball bearings such as contact pressure and velocities. Lubricant distribution by the contact area is analysed with fluorescent microscopy. Part of this thesis is a validation experiment and drawing documentation of the device.
Improving friction of lubricated contacts by modifying thermal conductivity
Šnevajs, Matěj ; Hartl, Martin (referee) ; Šperka, Petr (advisor)
This thesis deals with an experimental study regarding the effects of the thermal conductivity of contact bodies on the friction, lubricant film thickness and temperature distribution in EHL contact. The thesis focuses on the configuration of the ball on disc contact. The contact body materials are characterized by a wide range of thermal properties. New contact pairs are proposed and used in the study in order to make the contact bodies’ thermal properties dependent on the behaviour of EHL contact. The colorimetric interferometry method is used to measure the lubricant film thickness and the infrared thermography method is used to observe the temperature distribution in EHL contact. The author presents the assumed mechanism of heat transfer within EHL contact on the basis of different heat transfer mechanisms. The same conditions – such as the Hertz pressure, mean entrainment speed, sliding speed and ambient temperature – are induced for all the contact pair combinations. That is why the differences in the results are attributed to the different thermal phenomena in the contact, caused by the thermal properties of the contact bodies. In the case of contact bodies with a reduced heat dissipation capability, a reduction of the friction coefficient of up to 50 % is observed, which is attributed to an increase in the lubricant temperature, resulting in a decrease in its viscosity. This is confirmed by the infrared thermography method, whereby a significantly higher lubricant temperature is observed in the case of a combination of contact materials with a lower heat dissipation capability.
Animation of the stress-strain behaviour of helical springs
Gabriel, Tomáš ; Klapka, Milan (referee) ; Hartl, Martin (advisor)
This thesis is dedicated to the creation of educational animations depicting issues with the design of helical springs. Thesis contains collection of the necessary materials, describes the animating process and presents the final results. Main topics of the work are the stress across a cross-section of a loaded spring, fatigue and natural frequency of an oscillating spring.
Design of the device for research on lubrication of gears
Žáček, Jan ; Hartl, Martin (referee) ; Svoboda, Petr (advisor)
The master´s thesis is focused on the design and implementation of the laboratory stand for studying lubrication of gears. Specifically, to assess the effect of lubricant contamination on gears. The device uses the Niemann closed circuit concept which in practice is called „back to back“. Firstly, in the theoretical part, the test circuits uses for testing gears are described and one of the standardized procedure for experimentation is presented. Based on research studies, basic parameters for the design and creation of conceptuals are determined. The practical part consists not only the design of this stend, but also including test run and the description of the procedure on that device. The result of this master´s thesis is the functional experimental device for the future development of intelligent lubrication systems.
Friction Modification within Wheel-Rail Contact
Galas, Radovan ; Meierhofer, Alexander (referee) ; Pfaff, Raphael (referee) ; Hartl, Martin (advisor)
Předložená disertační práce se zabývá experimentálním studiem modifikátorů tření a maziv pro temeno kolejnice, které jsou aplikovány do kontaktu kola a kolejnice za účelem optimalizace adheze a redukce hluku. Hlavním cílem práce bylo objasnit vliv aplikovaného množství a složení těchto látek na adhezi v kontaktu. Hlavní pozornost byla věnována zejména potencionálním hrozbám souvisejících s kriticky nízkou adhezí, která může nastat po aplikaci těchto látek. Experimentální studium probíhalo v laboratorních i reálných podmínkách, konkrétně v tramvajovém provozu. V případě laboratorních experimentů byl využit komerční tribometr a dvoudiskové zařízení umožňující simulovat průjezd vozidla traťovým obloukem. Kromě samotné adheze bylo při experimentech sledováno také opotřebení a míra hluku. Výsledky ukázaly, že maziva pro temeno kolejnice jsou schopna poskytovat požadované třecí vlastnosti, nicméně jejich chování je silně závislé na aplikovaném množství. V případě předávkování kontaktu dochází ke kriticky nízkým hodnotám adheze, které vedou k výraznému prodloužení brzdné dráhy. V případě modifikátorů tření bylo ukázáno, že chování těchto látek je výrazně ovlivněno odpařováním základního média. Výsledky také ukázaly, že nadměrné množství částic pro modifikaci tření může způsobit kriticky nízké hodnoty adheze. U obou výše zmíněných typů produktů byl prokázán pozitivní vliv na míru opotřebení a míru poškození povrchu, zatímco významná redukce hluku byla dosažena pouze v případech, kdy došlo ke značnému poklesu adheze. V závěru této práce jsou uvedena doporučení pro další výzkumné aktivity v této oblasti.
Animation of slide bearnig function
Halama, Lukáš ; Křupka, Ivan (referee) ; Hartl, Martin (advisor)
This bachalor thesis deals with creation of animation, which illustrates basic facts about radial slide bearing with hydrodynamic lubrication. Animation will be used for education purpose.
Animation of the structural behavior of rod bolted joints
Farkaš, Richard ; Klapka, Milan (referee) ; Hartl, Martin (advisor)
This thesis deals with the investigation of the force-deformation behavior of prestressed crankshaft bolts, kinematics and dynamics within the crank mechanism of the four-stroke spark-ignition engine. This issue is illustrated by animations intended for educational purposes.
Animation of force relations on power screw
Jonáš, Tom ; Klapka, Milan (referee) ; Hartl, Martin (advisor)
The bachelor thesis deals with creating animations in program Cinema 4D. The animations show what forces are generated during nut movements along the moving bolt, also show self-locking conditions and geometry between forces. These animations will be used for educational purposes for students, for a better understanding of the issue, and for a better idea of spatial distribution of forces. The thesis describes the software environment and the process of creating particular animations.
Influence of friction modifiers composition on traction in wheel-rail contact
Kvarda, Daniel ; Hartl, Martin (referee) ; Galas, Radovan (advisor)
Friction modifiers are a new effective way to control adhesion in wheel and rail contact. The aim of this diploma thesis is experimental study of the influence of the constituents of water based friction modifier on adhesion. Measurement of the adhesion behavior for different friction modifier compositions is carried out on a ball–on–disc laboratory device creating point contact. The introductory part of the experiments describes the effect of individual components on adhesion. Subsequently, combinations of different friction modifier compositions are tested. In conclusion, selected compositions are used for wear tests. The results obtained show that the performance of friction modifiers is greatly influenced by evaporation of base medium.

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