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Study of bearing noise regarding accuracy of machining
Studýnka, Pavel ; Sabo, Karol (referee) ; Klapka, Milan (advisor)
This bachalor thesis deals with connection between the quality of surface of raceways of a bearing and vibrations in operation. This thesis describes basic geometrical parameters of a bearing that have main influence on its resulting quality and vibrations. It presents methods to evaluate the quality of the raceways surfaces and their connection between them. As a part of the thesis is an experiment, which should prove, what is the connection between the measuring of quality of the surface of raceways and measuring the vibrations of bearings during the process, by the way used in the company KOYO Olomouc. The quality of raceways is evaluated on a measuring device MUK-F 300 and vibrations on IL 100R/2000.
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Comparison of noise generated by differently constructed vents
Bernard, Jan ; Doložílek, Miroslav (referee) ; Jedelský, Jan (advisor)
This diploma thesis deals with comparing noise levels of three side vents of different constructions, which are used for distribution and directing of ventilation air in a cabin of an automobile. The fundamental knowledge of the physical and physiological acoustics is described in the introduction part of this study. Following the introduction part there is a brief explanation of the car air conditioning system (HVAC system) as well as are explained the acoustic properties of specific elements of this system. The study also deals with dividing ventilation vents and describes the vast traceable types of automobile vents. Prior to the description of the experiment, which was conducted as a part of this study, the procedures and results of the measurements carried out in other theses are explained. Measurement of noise levels of the compared vents was carried out in a semi-anechoic chamber under the ČSN ISO 3475 standardization. To clarify increase of noise generated by the vent in an interior of an automobile, additional measurement of noise was carried out in a cabin of Porsche Cayenne 2018. From the gathered results we can conclude that under the constant flow, (of 60 square meters per hour) louder vents are those with higher pressure loss. This pressure loss is dependant primarily on the speed of the flow in the vent, as well as on the number and the adjustment of the deflectors. In a cabin of an automobile, the noise produced by the vent is negligible in comparison with total noise in an interior of a car. However, in the area surrounding the air flowing out from the vent, (approximately 0,7 meters from it) the level of acoustic pressure increases significantly.
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Aspects impact trends in the operation technology of civil aviation aircraft
Korytář, Jan ; Šplíchal, Miroslav (referee) ; Chlebek, Jiří (advisor)
The aim of the work is a general description of the effects on air traffic and aircraft. The first part of the work is devoted to a brief description of the development of individual technical parameters and performance of aircraft from the 1920s to the present with an assessment of the effects. The second part of the work is about the influence of current requirements and the third part is a general view of the future development of construction and technology for more economical and environmentally friendly air transport
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Sound emission directivity model
Zdvyhal, Marian ; Hájek, Roman (referee) ; Hejčík, Jiří (advisor)
This diploma thesis solves creation of a computing model of sound propagation for determination of acoustic pressure level around multiple point sound source with consideration of sound directivity of each source (compresor and fan). Thesis contains neccesary theoretical knowledge for creation of computing model and basics of sound measuring, theoretical computing model, measurement data of real unit and model configuration for real measured values. Computing code of the model in Visual Basic for MS Excel is a part of the thesis.
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Intelligent Test Procedures Low-Tension Traction Drives with Induction Motors
Nesvadba, Martin ; Ondrůšek, Čestmír (referee) ; Novák, Jaroslav (referee) ; Duroň,, Jiří (referee) ; Singule, Vladislav (advisor)
This dissertation thesis is focused on the problem of the noise measurement and construction of the noise test station what was also interest of my employer - company Kollmorgen,sr.o. This testing station should be located directly in the assembly line with target of the noise motor s identification. On base of these measured values and implemented intelligent testing procedures, we should be able to identify real root cause of the noise The noise of electrical machines is actual issue. There is a big pressure for low-noise driving system construction created by many end-customers. We can achieve these requirements with 100% quality of all parts of current product, implementation of noise testing station and also with design optimization of the current product. Basic testing procedures of induction motors were showed in first part of this work (chapter 4.1.). These procedures are able to provide good picture of the motor condition. For the motor noise measurements was constructed a workplace including noise box with acoustical absorption up to 30dB what allowed the workplace implementation directly into the motor assembly line. Testing techniques and frequency analysis procedures were implemented sequentially with the target of the test evaluation improvement. After the detailed analyze of the motor noise root causes was performed check of the current motor design with respect of the “noiselessness” motor construction principles. As next step was created the motor prototype with optimized construction with target of the motor noise reduction. This optimized motor was tested and compared with standard motor design.
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Electric and Hybrid Vehicles Analysis
Slaběňák, Patrik ; Kuchyňková, Hana (referee) ; Hájek, Vítězslav (advisor)
Nowadays, oil resources start to decrease, therefore it is necessary to think about alternative sources of energy. The result of this semester project is a basic overview of the current development of electric and hybrid cars, with potential application in normal operation and the proximity of their main characteristics, such as mileage, price and service when traveling. The energy required to operate the electric stored in batteries are recharged using the power stations, which is also devoted part of the work. The thesis focuses on the design and calculation of power consumption for a defined route of four-wheel electric wheelchair. The conclusion of the thesis deals with the future development of hybrid and electric vehicles, and with the expected trends in the field of power electronics and motors and with the propagation of hybrid vehicles to the customers.
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Propfan engines in civil aviation transportation
Polák, Andrej ; Klement, Josef (referee) ; Šplíchal, Miroslav (advisor)
Bachelor thesis is written in the search form and discusses propfan aircraft engines. After introducing the concept itself, the first part deals with the principle functioning of engines and propulsion efficiency. The second part briefly describes the construction of these engines with a focus on specific parts of propfan engines differentiating concept from other aircraft engines. Then summarizes the features of these engines, describes their advantages and disadvantages and the possibilities of eliminating disadvantages. Finally briefly describes the history of the development of propfan engines.
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Aspects impact trends in the operation technology of civil aviation aircraft
Korytář, Jan ; Šplíchal, Miroslav (referee) ; Chlebek, Jiří (advisor)
The aim of the work is a general description of the effects on air traffic and aircraft. The first part of the work is devoted to a brief description of the development of individual technical parameters and performance of aircraft from the 1920s to the present with an assessment of the effects. The second part of the work is about the influence of current requirements and the third part is a general view of the future development of construction and technology for more economical and environmentally friendly air transport
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Unconventional range extender of an electric vehicle
Vysloužil, Marek ; Böhm, Michael (referee) ; Drápal, Lubomír (advisor)
This master´s thesis is dealing with the research of range extenders with internal combustion engine and the design of gasoline two-cylinder internal combustion engine with an unconventional parallel arrangement of crankshafts that meets mainly the requirements for low noise production and compact installation. It also describes the creation of a thermodynamic model and kinematic design using GT-Power. The computational part focuses on verifying the suitability of the chosen internal combustion engine concept used as range extender using advanced MBS methods.
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Pilový kotouč v procesu podélného řezání materiálů na bázi dřeva
Veselý, Přemysl
In this dissertation thesis there is listed characteristics of circular saw blades, their distribution, influence of construction adjustments on final behavior of blade in the process of machining, problematic of oscillation of blades a mutual interaction among quality of machined surface, noise and dust. The thesis covers the problems of oscillation of circular saw blades as when idling and operating - the cutting process; and by the use of three circular saw blades with different construction modifications. These aforementioned construction measures are also compared to each other due to the implementation of standard construction saw blades not only from the perspective of oscillation, but also from the perspective of the roughness of the machined surface and the analysis of wood waste generated during cutting and noise. In the theoretical part there is an analysis of available literature and scientific theses. It outlines the particular publications devoted to methods of determining the shapes of oscillation, determining critical, resonant and recommended speed, blade constructions, including possible modifications, the theory of cutting saw blades including determining the size and shape of the splints and the effects of noise on the work environment. An important part of this work is methodology involving direct measurements for detection of unstable states of discs (resonance and critical speed. In this section it is further evaluated measuring of the oscillation of the test saw blade and verification of the proposed methodology with a different and practiced, commonly known method, so called cold shapes: The author also seeks to explore and determine the effect of different tooth pitch and method of execution of slots along with soundproofing grooves on noise levels, the resulting quality of the machined surface of various wood. The generated waste is then analyzed for splitting wood particles in particular size group with the percentage of each chip. The results of the experiment are in discussion confronted with the available scientific theses, taking into account with normal operating conditions, of which the conclusion is drawn.
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