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Orientador: Robson Pederiva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-23T14:08:15Z (GMT). No. of bitstreams: 1 Martins_DiegoRodrigo_M.pdf: 7219918 bytes, checksum: 31c54119f27719f2488e9ea8f2a0126e (MD5) Previous issue date: 2013 / Resumo: O presente trabalho tem por objeto o estudo de sistemas de transmissão por correia serpentina com tensionador automático, que é uma aplicação automotiva utilizada em larga escala e cujo comportamento dinâmico apresenta grande influência sobre o funcionamento dos acessórios acionados pelo motor. O movimento do eixo de manivelas acionado pelo processo de combustão apresenta como característica a ocorrência de variações de velocidade e torque entregues aos acessórios pelo sistema de transmissão, contudo as flutuações de torque resultantes deste movimento são o principal mecanismo excitador do sistema de transmissão por correia. Níveis elevados de flutuação de torque podem aumentar o nível de tração dinâmica atuante na correia, fazendo com que esta venha a falhar devido à fadiga, ou produzir níveis de vibração torcional elevados nas polias dos acessórios, causando impacto direto em seus suportes. Através de modelos matemáticos é avaliado o comportamento do sistema de transmissão, considerando alguns fenômenos responsáveis por introduzir não linearidades neste. São avaliados, assim, os efeitos de tração inicial, frequências naturais, formas modais e respostas temporais do sistema. Paralelamente é estudado o comportamento de um sistema de transmissão real através da uma investigação experimental. São identificados seus parâmetros lineares através de técnicas de Análise Modal, bem como efeitos de variação destes parâmetros em função da velocidade de operação do sistema. É avaliada a composição em frequência da resposta do sistema quando em operação e também são realizados testes para detecção de não linearidades no sistema / Abstract: The objective of the present work is the study of a tensioner loaded belt drive system, which is a recurrent automotive application used in large scale and whose dynamic behavior has great influence on the functioning of various components powered by engine. Crankshaft motion, powered by internal combustion process, presents as characteristic the occurrence of variations on speed and torque delivered to accessory by belt drive, torque fluctuation due to this motion is the main excitation mechanism to belt drive systems though. High levels of torque fluctuation can increase belt dynamic tension making it amenable to fault due to fatigue or produce high levels of torsional vibration on accessory pulleys which has direct impact on its support structure. By means of mathematical models, systems behavior is evaluated, taking into account phenomena responsible for introducing nonlinearities. Initial tractive tension, natural frequencies, modeshapes and time responses of the system are evaluated. In parallel, it is studied the behavior of a real belt drive system through experimental investigation. Linear parameters are identified by Experimental Modal Analysis techniques, and its variation as function of system operating speed, as well. Frequency composition of system's response are evaluated and also are performed tests to detect nonlinearities / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Der zentrale Antrieb von Maschinen erfolgt häufig über einen Riementrieb, da eine Drehzahlanpassung einfach und kostengünstig zu realisieren ist. Für Maschinen mit hohen verarbeitungstechnischen Forderungen hinsichtlich der Qualität, z.B. zerspanende Werkzeugmaschinen oder Druckmaschinen, ist oftmals die Übertragungsgüte des Riementriebes der begrenzende Faktor für Leistungssteigerungen oder Qualitätsverbesserungen. Aus der Übertragungsgüte des Riementriebes resultieren dynamische Kräfte/ Momente, die als dynamischer Erreger in der Maschine wirken. Um den Einfluss der Übertragungsgüte eines Riementriebes zu verstehen, ist das dynamische Verhalten der gesamten Maschine notwendig zu betrachten. Dies wird kurz am Beispiel einer Druckmaschine erläutert. Grundvoraussetzung zur Verbesserung der Übertragungsgüte eines Riementriebes ist eine wiederholbare messtechnische Bestimmung der Übertragungsgüte. Die in der KBA genutzte und dazu entwickelte Methodik wird vorgestellt. Aus der messtechnischen Untersuchung zur Übertragungsgüte werden Frequenzbereichssowie Zeitbereichsergebnisse für die untersuchten Poly-V-Riemen präsentiert und interpretiert. Die ermittelten Abhängigkeiten, die vom Riemen selbst resultieren, sowie aus dem Zusammenwirken aller Bauteile eines Riementriebes beruhen, werden diskutiert. Die vorgestellte Methodik zur Bestimmung der Riemengüte ist nicht auf die Untersuchung von Poly-V-Riemen oder Riementrieben beschränkt und kann für alle gleichförmig übersetzenden Getriebe genutzt werden. Die Methodik ermöglicht nachfolgend eine extrem präzise Bestimmung der Übertragungsgüte. / The main drive of a machine is usually transferred through a belt drive as adjustments to speed can be carried out easily and cost effectively. The transmission quality of a belt drive is often a limiting factor when improving performance or quality for machines with technologically high finishing demands regarding quality, e.g. drilling and milling machines or printing presses. Dynamic forces/moments, which work as dynamic exciters in a machine, result from the transmission quality. In order to understand the influence of a belt drive’s transmission quality it is necessary to look at the dynamic behavior of an entire machine. This will be briefly explained using a printing press as an example. A repeatable metrological determination of the transmission quality is key to improving a belt drive’s transmission quality. The method developed and used at KBA will be presented in this article. The frequency range and time range results for the tested poly-V-belts from this metrological study on transmission quality will be presented and interpreted. Identified dependencies which result from the belts as well as the collective effect of all the components in a belt drive will be discussed in this article. The frequency range and time range results for the tested poly-V-belts from this metrological study on transmission quality will be presented and interpreted. Identified dependencies which result from the belts as well as the collective effect of all the components in a belt drive will be discussed in this article. The method presented for determining belt quality is not just limited to inspecting poly-V-belts or belt drives, it can be used for all uniform transmission gears. It allows transmission quality to be determined extremely precisely.

Der zentrale Antrieb von Maschinen erfolgt häufig über einen Riementrieb, da eine Drehzahlanpassung einfach und kostengünstig zu realisieren ist. Für Maschinen mit hohen verarbeitungstechnischen Forderungen hinsichtlich der Qualität, z.B. zerspanende Werkzeugmaschinen oder Druckmaschinen, ist oftmals die Übertragungsgüte des Riementriebes der begrenzende Faktor für Leistungssteigerungen oder Qualitätsverbesserungen. Aus der Übertragungsgüte des Riementriebes resultieren dynamische Kräfte/ Momente, die als dynamischer Erreger in der Maschine wirken. Um den Einfluss der Übertragungsgüte eines Riementriebes zu verstehen, ist das dynamische Verhalten der gesamten Maschine notwendig zu betrachten. Dies wird kurz am Beispiel einer Druckmaschine erläutert. Grundvoraussetzung zur Verbesserung der Übertragungsgüte eines Riementriebes ist eine wiederholbare messtechnische Bestimmung der Übertragungsgüte. Die in der KBA genutzte und dazu entwickelte Methodik wird vorgestellt. Aus der messtechnischen Untersuchung zur Übertragungsgüte werden Frequenzbereichssowie Zeitbereichsergebnisse für die untersuchten Poly-V-Riemen präsentiert und interpretiert. Die ermittelten Abhängigkeiten, die vom Riemen selbst resultieren, sowie aus dem Zusammenwirken aller Bauteile eines Riementriebes beruhen, werden diskutiert. Die vorgestellte Methodik zur Bestimmung der Riemengüte ist nicht auf die Untersuchung von Poly-V-Riemen oder Riementrieben beschränkt und kann für alle gleichförmig übersetzenden Getriebe genutzt werden. Die Methodik ermöglicht nachfolgend eine extrem präzise Bestimmung der Übertragungsgüte. / The main drive of a machine is usually transferred through a belt drive as adjustments to speed can be carried out easily and cost effectively. The transmission quality of a belt drive is often a limiting factor when improving performance or quality for machines with technologically high finishing demands regarding quality, e.g. drilling and milling machines or printing presses. Dynamic forces/moments, which work as dynamic exciters in a machine, result from the transmission quality. In order to understand the influence of a belt drive’s transmission quality it is necessary to look at the dynamic behavior of an entire machine. This will be briefly explained using a printing press as an example. A repeatable metrological determination of the transmission quality is key to improving a belt drive’s transmission quality. The method developed and used at KBA will be presented in this article. The frequency range and time range results for the tested poly-V-belts from this metrological study on transmission quality will be presented and interpreted. Identified dependencies which result from the belts as well as the collective effect of all the components in a belt drive will be discussed in this article. The frequency range and time range results for the tested poly-V-belts from this metrological study on transmission quality will be presented and interpreted. Identified dependencies which result from the belts as well as the collective effect of all the components in a belt drive will be discussed in this article. The method presented for determining belt quality is not just limited to inspecting poly-V-belts or belt drives, it can be used for all uniform transmission gears. It allows transmission quality to be determined extremely precisely.

Most engineering systems are highly nonlinear in nature and thus one could not develop efficient mathematical models for these systems. Artificial neural networks, which are used in estimation, filtering, identification and control in technical literature, are considered as universal modeling and functional approximation tools. Unfortunately, developing a well trained monolithic type neural network (with many free parameters/weights) is known to be a daunting task since the process of loading a specific pattern (functional relationship) onto a generic neural network is proven to be a NP-complete problem. It implies that if training is conducted on a deterministic computer, the time required for training process grows exponentially with increasing size of the free parameter space (and the training data in correlation). As an alternative modeling technique for nonlinear dynamic systems / this thesis proposed a general methodology for structured neural network topologies and their corresponding applications are realized. The main idea behind this (rather classic) divide-and-conquer approach is to employ a priori information on the process to divide the problem into its fundamental components. Hence, a number of smaller neural networks could be designed to tackle with these elementary mapping problems. Then, all these networks are combined to yield a tailored structured neural network for the purpose of modeling the dynamic system under study accurately. Finally, implementations of the devised networks are taken into consideration and the efficiency of the proposed methodology is tested on four different types of mechanical systems.

The thesis presents the design and analysis of a Twin Tensioner for a Belt-driven Integrated Starter-generator (B-ISG) system. The B-ISG is an emerging hybrid transmission closely resembling conventional serpentine belt drives. Models of the B-ISG system's geometric properties and dynamic and static states are derived and simulated. The objective is to reduce the magnitudes of static tension in the belt for the ISG-driving phase. A literature review of hybrid systems, serpentine belt drive modeling and automotive tensioners is included. A parametric study evaluates tensioner parameters with respect to their impact on static tensions. Design variables are selected from these for an optimization study. The optimization uses a genetic algorithm (GA) and a hybrid GA. Results of the optimization indicate the optimal system contains spans with static tensions that are significantly lower in magnitude than that of the original design. Implications of the research on future work are discussed in closing.

The thesis presents the design and analysis of a Twin Tensioner for a Belt-driven Integrated Starter-generator (B-ISG) system. The B-ISG is an emerging hybrid transmission closely resembling conventional serpentine belt drives. Models of the B-ISG system's geometric properties and dynamic and static states are derived and simulated. The objective is to reduce the magnitudes of static tension in the belt for the ISG-driving phase. A literature review of hybrid systems, serpentine belt drive modeling and automotive tensioners is included. A parametric study evaluates tensioner parameters with respect to their impact on static tensions. Design variables are selected from these for an optimization study. The optimization uses a genetic algorithm (GA) and a hybrid GA. Results of the optimization indicate the optimal system contains spans with static tensions that are significantly lower in magnitude than that of the original design. Implications of the research on future work are discussed in closing.

The subject of this diploma thesis is especially design of main conception of one purpose machine for outinsulating of flat cables. Designed solution must implement basic requirements of outinsulating‘s quality. Part of this thesis includes also technical-economics evaluation of choosed solution and analysis of risks.

Indiana University-Purdue University Indianapolis (IUPUI) / This thesis presents a comprehensive study of the effects of material, geometric and operational parameters on flat belt-drives steady-state belt stresses, belt slip, and belt-drive efficiency. The belt stresses include: belt rubber shear, normal, axial and lateral stresses; reinforcements tension force; and tangential and normal belt-pulley contact stresses. Belt slip is measured using the driven over driver pulleys’ angular velocity ratio. Each parameter was varied over a range to understand its impact on the steady-state belt-drive response. The material parameters studied are belt axial stiffness and damping, belt bending stiffness and damping, and belt-pulley friction coefficient. The geometric parameters studied are pulley center distance, pulleys diameter ratio, and belt thickness. The operational parameters studied are the driver pulley angular velocity and the driven pulley opposing torque (load). A high-fidelity flexible multibody dynamics parametric model of a two-pulley belt-drive system was created using a commercial multibody dynamics code. In the model the belt’s rubber matrix is represented using three-dimensional brick elements and the belt’s reinforcements are represented using one dimensional beam elements at the top surface of the belt. An asperity-based Coulomb friction model is used for the friction forces between the pulley and belt. The pulleys are modeled as rigid bodies with a cylindrical contact surface. The equations of motion are integrated using an explicit solution procedure. Unlike prior models which use one-dimensional truss or beam elements for the belt, the present model uses a three-dimensional belt model which introduces the effect of the thickness of the belt rubber matrix (modeled using brick elements). This enables a more accurate prediction of the belt stresses and slip than prior models. This thesis resolves in more details the complex stick-slip friction behavior of an axially flexible belt coupled with the shear effects of a flexible rubber cushion and at the same time shows the effect of the main system parameters on this stick-slip behavior. Some of the important conclusions of the thesis include: (1) the driver pulley has two distinct contact zones - a negative traction zone and a positive traction zone - while only one traction zone is present over the driven pulley; (2) the width of the negative traction zone on the driver pulley increases with the belt-pulley coefficient of friction and decreases with the belt axial stiffness; (3) the maximum belt tension and normal contact stress occur on the driver pulley and increase with the belt thickness, belt axial stiffness, and coefficient of friction; (4) belt-drive energy efficiency increases with the belt axial stiffness, and decreases with belt thickness, belt bending damping, belt operating speed, and operating torque load. The belt-drive modeling methodology presented in this thesis which enables accurate prediction of the belt stresses and slip can in turn be used to more accurately predict the fatigue life, wear life, and energy efficiency of belt-drives.

Design of linear actuator for parallel kinematic structure is described in this master´s thesis. The parallel kinematic structure is described in the first part. Open kinematics structure and close kinematics structure are compared. Their benefits and disadvantages are also mentioned. Construction of some parallel robots is illustrated. Linear actuators of different company are described. Mechanical parameters and construction of linear actuator are compared. Design of linear actuator is described in practical part of master´s thesis. A few variation of linear actuator are introduced. Individual variants are evaluated by Multicriteria Decisional Analysis and a final conception is selected. Final conception of linear actuator is elaborated. Reasons for selection of every part of linear actuator are given and basic mechanical calculation design part is made. FEA analysis of the structural part of linear actuator is made. Design of linear actuator is evaluated in the final part.