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Cranktrain with High Mechanical Efficiency
Krajči, Jakub ; Raffai, Peter (referee) ; Novotný, Pavel (advisor)
This master's thesis is concerned with the mechanical efficiency of cranktrain contact pairs in a combustion engine. In the introductory part, the fundamental terminology relating to the cranktrain is presented along with the specification of the areas of mechanical losses, greasing modes and types of wear. The following chapters describe the possibilities of eliminating mechanical losses of the cranktrain and the calculation methods that can be utilized to mathematically solve mechanical losses. The practical part includes the proposal of a calculation model and its use in the analysis of the cranktrain of Skoda 1.2 HTP engine. The last part of this thesis comprises modified alternatives of the standard cranktrain focusing on the elimination of mechanical losses. The evaluation of the results is presented in the conclusion of this thesis.
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Power Losses of a Rolling Bearing
Šedo, Matej ; Novotný, Pavel (referee) ; Drápal, Lubomír (advisor)
Subject of this thesis is analysis of friction power losses in rolling bearings and design and implementation of computing program. Thesis is divided into six chapters. At the beginning there is overview of different types of rolling bearings and their system of lubrication. Fundamentals of elastohydrodynamic lubrication are described together with effects that occur in lubricant. Remaining part is focused on friction in rolling bearing its sources and calculation. Other programs for computing friction losses are shown and own program is designed. Designed program is applied on bearings of chosen type and results are compared with existing models.
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The influence of the frequency converter on the life and damage of bearings
Sukovatý, Adam ; Krejčí, Petr (referee) ; Nahodil, Petr (advisor)
This thesis deals with the effect of frequency inverter on the lifetime of roller bearings. The measurement has been carried out on the frequency inverter and induction motor by Siemens in the Switchgear laboratory of Fakulty of elektrical engineering and communication. Data has been recorded and processed on Adash VA4 Pro analyzer. Methods of measuring RMS values and frequency analysis of vibration and current were used for the analysis. Based on the mutual similarity of frequency spectrum, the presence of the high frequency capacitive current in the bearings has been proven. To prevent this, possible solutions have been presented. In the second part of the experiment an effect of changing pulse width modulation (PWM) on vibration was examined. The goal was to make a basic analysis and to provide background material for further research.
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Reducing vibration and noise of bearings
Nejeschleba, Martin ; Prostredník, Daniel (referee) ; Jankových, Róbert (advisor)
The diploma thesis deals with the issue of bearings noisiness. The bearings noisiness appears as a negative phenomenon in all the mechanical devices that generate any kind of movement. Analysis of this phenomenon enables to analyse the technical condition of the bearing and predict its defects as well. The theoretical part of the thesis is devoted to the vibration diagnostics and noisiness diagnostics, which are deeply linked. The practical part of the thesis deals with the real problem of the bearing’s noisiness in the engineering company. The main asset of this thesis is a design and successful implementation of the measures, which reduce noisiness of the selected type of the bearing.
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Diagnosis of mechanical vibrations in asynchronous motor origin
Dostál, Martin ; Dostál, Lukáš (referee) ; Janda, Marcel (advisor)
Every machine needs to be maintained and controlled, if may work reliably during they service life. Big part of service life of expensive machines are those machines in operation. Vibration diagnostics is type of analysis, that doesn’t need removal of rotation machinery. The vibration, that are created by running machinery, are used as source of information about mode of operation. This master’s thesis contains theoretical analysis of vibration diagnostics and vibration measurements of a particular machine. This thesis contains 3D models of bearings and rotor asynchronous machine, which are created by software Autodesk Inventor 2014. Bearings vibration analysis of this models is performed by software Ansys Workbench.
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Noise control of needle bearings
Štetinová, Iveta ; Krejčí, Jakub (referee) ; Šedivá, Soňa (advisor)
The bachelor thesis deals with the noise of needle bearings. By analysing the noise of the bearings, it is possible to find out the technical condition of the bearing and reveal the types of bearing damage. The beginning of the work is devoted to the theory of bearing noise. Vibration diagnosis methods are described. In the practical part, a manual noise meter is tested, and the investigated values are evaluated by a system for measuring the noise of bearings. The primary objective of this thesis is to find out how the noise of the bearings could be controlled more effectively.
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Rolling bearing stiffness calculation
Koban, Tomáš ; Vlach, Radek (referee) ; Lošák, Petr (advisor)
In this thesis, an analytical approach for calculating the bearing stiffness of ball and cylindrical roller bearings is presented. Three mathematical models have been developed for the case of axial, radial and combined loading. All presented models use Hertz contact theory for determining the roller-raceway contact behavior. Analytical approach is then compared with FEA results. The static numerical simulation of a roller bearing is detailly described. The comparison between analytical and numerical approach is presented for single-row angular contact ball bearing 7304 BECBM and single-row radial cylindrical roller bearing NU 202 ECP. The results show a comprehensive comparison of bearing deflections, internal load distribution and bearing stiffness for each model.
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Reducing vibration and noise of bearings
Nejeschleba, Martin ; Prostredník, Daniel (referee) ; Jankových, Róbert (advisor)
The diploma thesis deals with the issue of bearings noisiness. The bearings noisiness appears as a negative phenomenon in all the mechanical devices that generate any kind of movement. Analysis of this phenomenon enables to analyse the technical condition of the bearing and predict its defects as well. The theoretical part of the thesis is devoted to the vibration diagnostics and noisiness diagnostics, which are deeply linked. The practical part of the thesis deals with the real problem of the bearing’s noisiness in the engineering company. The main asset of this thesis is a design and successful implementation of the measures, which reduce noisiness of the selected type of the bearing.
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The influence of the frequency converter on the life and damage of bearings
Sukovatý, Adam ; Krejčí, Petr (referee) ; Nahodil, Petr (advisor)
This thesis deals with the effect of frequency inverter on the lifetime of roller bearings. The measurement has been carried out on the frequency inverter and induction motor by Siemens in the Switchgear laboratory of Fakulty of elektrical engineering and communication. Data has been recorded and processed on Adash VA4 Pro analyzer. Methods of measuring RMS values and frequency analysis of vibration and current were used for the analysis. Based on the mutual similarity of frequency spectrum, the presence of the high frequency capacitive current in the bearings has been proven. To prevent this, possible solutions have been presented. In the second part of the experiment an effect of changing pulse width modulation (PWM) on vibration was examined. The goal was to make a basic analysis and to provide background material for further research.
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