Les couples d'engrenages présents dans les boîtes de vitesses automobiles sont une source de bruit importante à prendre en compte et à maîtriser. L'acyclisme du moteur observable en entrée de boîte a notamment pour conséquence de provoquer des impacts entre les dents des engrenages non chargés, à l'origine du bruit de grenaille. Ce travail de thèse s'intéresse aux cas de grenaille dits périodiques, dont l'apparition et la sévérité dépendent, entre autres, des conditions de fonctionnement régime/charge. Pour détecter la présence et quantifier la sévérité de ce bruit, il est nécessaire de construire des indicateurs pertinents et dédiés, où il est particulièrement intéressant de conserver la dualité des informations temporelles (relatives aux voies de transfert des phénomènes vibratoires) et angulaires (relatives aux cycles de la machine) mesurées sur des boîtes en montée de régime. Une extension de l'approche cyclostationnaire classique est ainsi exploitée et la cohérence spectrale ordre/fréquence est utilisée afin de définir un indicateur de sévérité du bruit de grenaille. Deux campagnes d'essais ont été réalisées afin de valider la pertinence de cet indicateur, utilisant un banc d'essais qui permet d'imposer des montées en régime et de générer un acyclisme. Dans la première campagne d'essais, un pignon fou est instrumenté à l'aide d’un codeur optique afin de mesurer la vitesse relative pignon fou/pignon menant qui est utilisée comme référence pour détecter l'apparition des impacts. La comparaison avec l'indicateur proposé, calculé à partir du signal vibratoire d'un accéléromètre positionné sur le carter de boîte, démontre sa capacité à détecter effectivement des chocs. Des sessions d'écoute ont été organisées afin de comparer le ressenti d'auditeurs qualifiés pour faire des évaluations subjectives à l'évolution des valeurs données par l’indicateur, à partir d'une seconde campagne d'essais. Cet indicateur apparaît représentatif du ressenti des auditeurs. Une fois la grenaille détectée et quantifiée globalement en intensité, il est intéressant d'extraire sa composante du signal global mesuré. Pour cela, une extension du filtre de Wiener cyclique pour des signaux cyclostationnaires angle/temps est proposée. Le signal extrait étant supposé être généré uniquement par les impacts produisant le bruit de grenaille, les impulsions extraites sont exploitées afin d'estimer la fonction de transfert entre les points d'excitation et le capteur localisé sur le carter de boîte. Cette fonction de transfert est comparée à celle obtenue par une seconde méthode, également développée dans le cadre de cette thèse, qui consiste en une extraction de la partie déterministe de l'excitation à l'aide d'un filtre en peigne dans le domaine des ordres, puis en une identification aveugle de la réponse impulsionnelle dans le domaine cepstral. / The improvement of the engine noise emissions causes the emergence of new sources which were previously masked, like gearbox noises. Because of the engine acyclism some impacts can appear between the teeth of unloaded gears. Those impacts generate the so called rattle noise which is a current problem for car manufacturers. This work is focused on periodic cases of rattle noise. Their appearance and their level depend on operating conditions. In order to propose a specific detection indicator it is particularly useful to exploit the angle/time duality from measures in non-stationary conditions: the angle domain is linked to the periodicity of the impacts while the time domain is linked to their nature. An extension of the cyclostationary approach is thus exploited and the order/frequency spectral coherence is used to define a severity indicator of rattle noise. The validation of this indicator is obtained from measurements. For a first level of validation, a loose gear has been instrumented with an optical encoder in order to measure the relative velocity between this loose gear and the driving gear. The comparison with the proposed indicator shows its ability to effectively detect the impacts. For a second level of validation some listening sessions have been organized. The evolution of values of our indicator appears in accordance with the feeling of the listeners. After the detection of rattle noise it is interesting to extract its contribution from the measured signal. An extension of the cyclic Wiener filter is thus proposed for angle/time cyclostationary sources. The extracted signal being supposed only produced by impacts, the extracted impulses are then exploited in order to estimate a transfer function. This transfer function is compared with the other one obtained by a second method, also developed in this work. This method exploits the non-stationary regime and proposes a blind identification with cepstrum.

This thesis deals with the vibration and noise of the gearbox for an electric vehicle. The gearbox itself acts as an emitter of unwanted noise caused by vibration excitation of the internal components of the gearbox. It is therefore necessary to deal with a complex unit such as the gearbox at system level as soon as it is being designed. This can be achieved using analytical tools and software. In this thesis, in order to evaluate the validity of the designed gearbox, a procedure is developed using both technical experiment and numerical simulations. The effect of the bolt preload is not overlooked for the following computational modelling dealing with the radiated noise of the gearbox. The results obtained from the performed technical experiments were then evaluated and compared with the results of the computational models. In this way, it is possible to compare the different approaches, their limitations and weaknesses. Furthermore, the thesis deals with design modifications that are analyzed using computational modeling. The thesis is concluded with a brief description of the application of each approach and an evaluation of the gearbox design modifications.

This master’s thesis deals with determination of NVH parameters of the gearbox housing. Introductory part is focused on the necessary theoretical knowledge. Subsequently, it contains the modal analysis with the computational and experimental approach, which are being compared to each other. In the case of the computational approach, analysis of the influence of bolt pretension on the modal properties is also involved. The thesis continues with the harmonic analysis with the computational and experimental approach, including their mutual comparison. Based on these analyses, design modifications for improvement of the NVH parameters are designed at the end of the thesis, which are being compared to each other and to the original geometry, using the computational approach.

This final diploma thesis deals with the issue of vibration and noise measurement of transmission devices. The research part describes the basic issues of noise and vibration generation, their measurement, as well as sources of vibrations in gear units. The practical part deals with the design proposal of the attachment of the experimental single-stage gearbox and the load dynamometer to the anechoic chamber including the drawings. Further, by checking the modal properties of the proposed test stand, using the finite element method, the analytical and numerical control of the torsional vibrations of the rotating parts with respect to the expected frequency ranges of use.

This master’s thesis deals with determination of NVH parameters of the gearbox housing for electric vehicle. The introduction part is focused on the theoretical knowledge of this issue. Subsequently, the deviations of geometry on the gearbox were measure by 3D scan method. The next part of thesis is focused on the modal analysis, which is solved by numerical approach and followed by experimental verification. During the numerical calculation solving, the influence of the screw preloading on the modal properties of the structure, was also taken into account. Numerical harmonic analysis was then performed and the results were compared with the experimental approach. The conclusion is devoted to material damping and comparison of the individual results.

The submitted project deals with a complete design of a gearbox of a portable ground power generator designed for preflight preparation of helicopters. The gearbox has been designed to meet given specifications, which are based on required electrical parameters of the entire power unit and with regards to parameters of driving turbine engine. The introductory section deals with a kinematical design of transmission gears with regards to required parameters and design constraints. The kinematical design determines whole concept and resulting form of the gearbox. Next part deals with optimization of gearing, the design of wheel bearing, and design of oil system. The implementation part of the project consists in the engineering design of the gearbox, which was made in 3D environment Pro/Engineer. The design is reviewed and first operational results of manufactured and tested gearbox are discussed in the concluding section of this work.

The main theme of this thesis is an analysis, desing and construction of a planetary gearbox used for a drive of a vertical lathe table. The theoretical part of the thesis describes fundamental features and terms of planetary gearboxes and torque motors. In the next part of my work I design loose functioning of toothing. The calculation part of my work is processed in accordance with technical standards. The practical part of my work deals with a description of the project and the implementation of the device. The drawing documentation is processed with Cad system and it includes general assembly drawing and drawings of the three important components.

This master’s thesis deals with the structural analysis of the gearbox housing and drive frame of bucket-wheel stacker/reclaimer. Theme is designed by Vítkovice Gearworks a.s. Objective of the work is to determine the size of the forces in the gears, bearings and perform strain stress analysis. The main part of the work is focused on creating finite element model in software NX I-Deas. The solution and evaluation is performed in software MSC Marc.

This diploma thesis describes a design of condensing steam turbine out of entered data of vapor parameters. There is selected a reaction blading type according to a conception of the company PBS Energo PLC. The turbine has one controlled extraction and three uncontrolled ones. The work also includes a proposal of thermal scheme, bearing and gearbox assignment. Furthermore there is also made a draft design of longitudinal section turbine

Diese Arbeit beschäftigt sich mit den in konventionellen Handschaltgetrieben als auch in automatisierten Schaltgetrieben für die Funktion "Schalten/Leistungsfluss herstellen" verwendeten Zahnkupplungen. Einmal eingelegt soll der gewählte Gang bis zur Herausnahme durch den Fahrer den Leistungsfluss gewährleisten. Es gibt aber Getriebe, bei denen sich eine korrekt betätigte Schalteinrichtung während der Fahrt selbsttätig wieder entkoppelt. Mit der vorliegenden Arbeit wird dieses Problem, als „Gangspringen“ bezeichnet, erklärt und analysiert. Das Ergebnis dieser Arbeit sind Vorschläge und Möglichkeiten zur Vermeidung dieser Fehlfunktion.