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1
Sainte-Marie, Nina. "A transmission-error-based gear dynamic model : Applications to single- and multi-mesh transmissions". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI133/document.
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Les spectres de bruit mesurés en cabine d’hélicoptère montrent que la boîte de transmission principale (BTP) est un des principaux contributeurs au bruit perçu par les usagers. Elle génère en effet plusieurs raies émergeant fortement du bruit large bande et dont les fréquences se situent dans la plage de sensibilité maximale de l’oreille humaine. Dans un contexte d’amélioration permanente du confort acoustique des usagers, un modèle numérique est développé pour prédire le comportement dynamique des BTP. Les équations du mouvement sont écrites sur la base de fonctions du temps représentatives des excitations générées par l’engrènement (raideur d’engrènement et erreurs de transmission). Plusieurs éléments de validation sont présentés pour confirmer la pertinence de la formulation proposée. Différents résultats numériques et expérimentaux de la littérature sont utilisés à des fins de comparaison, montrant que le modèle s’applique aux systèmes à simple étage de réduction, par engrenage cylindrique ou spiro-conique. La validation est ensuite étendue aux systèmes à deux étages de réduction et les résultats confirment que la formulation basée sur les erreurs de transmission permet de tenir compte des corrections de profil. Finalement, le modèle est utilisé pour diverses applications. Premièrement, l’influence des erreurs de pas sur le comportement dynamique de transmissions par engrenages est discutée, ainsi que l’influence combinée du niveau de chargement appliqué. Dans un second temps, la relation entre l’erreur de transmission dynamique et différents coefficients dynamiques est étudiée. Le contenu spectral de la réponse au niveau des roulements est ensuite analysé pour des systèmes à deux engrènements cylindriques et l’influence de différents paramètres est discutée. Enfin, une application est réalisée sur un système comprenant un engrenage cylindrique et un engrenage spiro-conique. Les phénomènes de couplage entre les étages successifs sont mis en évidence ainsi que la contribution des deux engrènements au contenu spectral de la réponse aux roulementsNoise measurements have shown that helicopters main gearboxes highly contribute to the overall cabin noise. Gear mesh vibrations propagate through the shafts to the rolling element bearings and the casing which becomes a source of radiated noise. The latter is characterized by high-amplitude tones emerging from broadband noise whose frequencies lie in the range of maximum human ear sensitivity. In the context of continuous improvement in the acoustic comfort of helicopter passengers, it is therefore necessary to analyse and optimize gearbox vibrations in order to reduce casing noise radiations. The research work presented in this memoir is focused on the development of a numerical model dedicated to the prediction of gear system dynamic behaviour, comprising several gear stages and different types of gears. This model relies on classic beam and lumped parameter elements along with specific two-node gear elements for both cylindrical (spur, helical) and spiral-bevel gears. The equations of motion are developed based on time-varying functions representative of mesh excitations which comprise: (a) mesh stiffness functions, (b) quasi-static transmission error under load, and (c) kinematic (or no-load) transmission error. A number of comparisons with benchmark numerical and experimental results from the literature are presented which demonstrate that the proposed approach is sound as far as single-stage systems with spur, helical or spiral-bevel gears are considered. Validations are then extended to double-stage gears and, here again, it is confirmed that the proposed transmission error based formulation is accurate and can account for tooth shape modifications. In the second part of the memoir, several examples of application are presented and commented upon. First, the combined influence of tooth pitch errors and load on the dynamic behaviour of gear transmissions is tackled. An extended three-dimensional model and a reduced torsional version are then confronted in order to investigate the dependency between dynamic transmission errors and mesh force / root stress dynamic factors. Further investigations on bearing dynamic response in two-stage spur gear systems are conducted and the particular contributions of profile modifications are analysed. Finally, a system combining a cylindrical gear and a spiral-bevel gear is considered and particular attention is paid to the dynamic couplings between the various meshes and their influence on bearing dynamic responses
2
Janakiraman, Venkatakrishna. "Modelling of Steady-State and Transient Power Losses in Planetary Gear Trains". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492510708602145.
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Kurth, Franz [Verfasser]. "Efficiency Determination and Synthesis of Complex-Compound Planetary Gear Transmissions / Franz Kurth". München : Verlag Dr. Hut, 2012. http://d-nb.info/1029400172/34.
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4
Brauer, Jesper. "Investigation of transmisison error, friction and wear in anti-backlash involute gear transmissions". Doctoral thesis, KTH, Machine Design, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3590.
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Brethee, Khaldoon F. "Condition monitoring of helical gear transmissions based on vibration modelling and signal processing". Thesis, University of Huddersfield, 2018. http://eprints.hud.ac.uk/id/eprint/34519/.
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Condition monitoring (CM) of gear transmission has attracted extensive research in recent years. In particular, the detection and diagnosis of its faults in their early stages to minimise cost by maximising time available for planned maintenance and giving greater opportunity for avoiding a system breakdown. However, the diagnostic results obtained from monitored signals are often unsatisfactory because mainstream technologies using vibration response do not sufficiently account for the effect of friction and lubrication. To develop a more advanced and accurate diagnosis, this research has focused on investigating the nonlinearities of vibration generation and transmission with the viscoelastic properties of lubrication, to provide an in-depth understanding of vibration generating mechanisms and hence develop more effective signal processing methods for early detection and accurate diagnosis of gear incipient faults. A comprehensive dynamic model has been developed to study the dynamic responses of a multistage helical gear transmission system. It includes not only time-varying stiffness but also tooth friction forces based on an elastohydrodynamic lubrication (EHL) model. In addition, the progression of a light wear process is modelled by reducing stiffness function profile, in which the 2nd and 3rd harmonics of the meshing frequency (and their sidebands) show significant alteration that support fault diagnostic at early stages. Numerical and experimental results show that the friction and progressive wear induced vibration excitations will change slightly the amplitudes of the spectral peaks at both the mesh frequency and its sideband components at different orders, which provides theoretical supports for extracting reliable diagnostic signatures. As such changes in vibrations are extremely small and submerged in noise, it is clear that effective techniques for enhancing the signal-to-noise ratio, such as time synchronous averaging (TSA) and modulation signal bispectrum (MSB) are required to reveal such changes. MSB is preferred as it allows small amplitude sidebands to be accurately characterised in a nonlinear way without information loss and does not impose any addition demands regarding angular displacement measurement as does TSA. With the successful diagnosis of slight wear in helical gears, the research progressed to validate the capability of MSB based methods to diagnose four common gear faults relating to gear tribological conditions; lubrication shortfall, changes in lubrication viscosity, water in oil, and increased bearing clearances. The results show that MSB signatures allows accurate differentiation between these small changes, confirming the model and signal processing proposed in this thesis.
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Fargere, Romain. "Simulation du comportement dynamique des transmissions par engrenages sur paliers hydrodynamiques". Thesis, Lyon, INSA, 2012. http://www.theses.fr/2012ISAL0130/document.
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Ce travail vise à prédire le comportement dynamique de transmissions par engrenages supportées par des paliers hydrodynamiques, semblables à celles utilisées dans le domaine de la propulsion navale. Un modèle couplé de transmission mécanique est présenté ; il traite la plupart des interactions possibles entre les engrenages, les arbres et les paliers. Un élément d’engrenages à dentures larges, avec raideur non linéaire et dépendante du temps, est combiné à des éléments finis de poutre alors que la contribution des paliers est introduite par la résolution directe de l’équation de REYNOLDS et d’un model thermique simplifié. A cause des jeux de fonctionnement des paliers, une attention particulière a été portée à la définition de l’état de référence et des degrés de liberté. La réponse du système est calculée par la combinaison d’un schéma d’intégration temporelle, d’une méthode de NEWTON-RAPHSON et d’un algorithme de contact normal unilatéral de manière à ce que les conditions de contact aux paliers et entre les dents soient simultanément traitées. Les résultats de simulation sont comparés à des mesures réalisées sur un banc d’essai de haute précision possédant un train simple étage en dentures droites et hélicoïdales, supporté par des paliers lisses de type hydrodynamique. Les comparaisons fournissent un bon accord et aboutissent à la validation du modèle de couplage tant sur les aspects globaux que locaux. Bon nombre de résultats sont également présentés, qui montrent que certains paramètres, bien souvent ignorés dans les modèles de la littérature, tels que la position de la zone d’alimentation des paliers, la température de lubrifiant dans les paliers, les accouplements avec l’environnement extérieur peuvent fortement modifier l’équilibre statique et le comportement dynamique du système, jusqu’aux contacts entre les dentsThe present work is aimed at predicting the dynamic behaviour of geared transmissions supported by hydrodynamic journal bearings, similar to those used in naval propulsion. A global model of mechanical transmissions is introduced which deals with most of the possible interactions between gears, shafts and hydrodynamic journal bearings. A specific element for wide-faced gears with non linear time-varying mesh stiffness and tooth shape deviations is combined with shaft finite elements whereas the bearing contributions are introduced based on the direct solution of REYNOLDS’ equation and a simple thermal model. Because of the large bearing clearances, particular attention has been paid to the definition of the degrees-of-freedom and their datum. Solutions are derived by combining a time-step integration scheme, a NEWTON-RAPHSON method and a normal contact algorithm in such a way that the contact conditions in the bearings and on the gear teeth are simultaneously dealt with. The simulation results are compared with the measurement obtained on a high-precision test rig with single stage spur and helical gears supported by hydrodynamic journal bearings. The experimental and simulation results compare well thus validating the simulation strategy both at the global and local scales. A number of results are presented which show that parameters often discarded in global models such as the location of the oil inlet area, the oil temperature in the bearings and external couplings with mechanical parts can be influential on the static and dynamic behaviour of the system
7
White, Robert J. "Exploration of a Strategy for Reducing Gear Noise in Planetary Transmissions and Evaluation of Laser Vibrometry as a Means for Measuring Transmission Error". Case Western Reserve University School of Graduate Studies / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=case1129928063.
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Larsson, Camilla. "Reduction of oil pump losses in automatic transmissions". Thesis, Linköpings universitet, Fordonssystem, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-111937.
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In the vehicle industry it is of great interest to reduce the emissions and lower the fuel consumption.Up to now a lot of effort has been put into increasing the efficiency of the engine,but it starts to get expensive to keep improving the engine. In this master thesis the transmissionand especially the oil supply to the transmission is investigated. An example of how the requirements of an oil pump can be decided is described. Knowingthe requirements different pumps may be adapted to meet the demands. The gear pumpused today is compared with a variable displacement pump and an electric pump. The gearpump is not possible to control, but the other two are. A few simple control strategies areintroduced. The strategies are implemented and the three pumps are used in the same drivecycle. It is shown that it is possible to reduce the energy that the pump requires if it isreplaced by a variable vane pump or an electric pump.
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Vinayak, Harsh. "Multi-body Dynamics and Modal Analysis Approaches for Multi-mesh Transmissions with Compliant Gear Bodies". The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1392059093.
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Terrin, Andrea. "Analysis and design against pitting of gears in power transmissions for off-highway vehicles". Doctoral thesis, Università degli studi di Padova, 2017. http://hdl.handle.net/11577/3426672.
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The work described in this thesis has been developed within the scope of a higher education apprenticeship program in cooperation with Carraro S.p.A., global player in the market of power drivelines for vehicles employed in industrial and agricultural applications, also addressed as off-highway vehicles. The study is aimed to the analysis of the mechanisms leading to contact fatigue failures of gears and to the development of reliable and efficient methods to characterize gears materials. Pitting is the most hazardous among rolling contact fatigue phenomena occurring in gears. It manifests with the formation of craters on the surfaces leading to noise, vibration and loss of efficiency, and eventually may constitute the initiation cause for secondary damages such as tooth fractures. The sun gears of the planetary gear sets, which constitute the final stage of reduction in off-highway drivelines, are particularly susceptible to pitting failures, being subjected to high torques under poor lubricating conditions determined by the low speed of rotation.
In this work, contact fatigue phenomena are studied by the observation of their occurrence in sun gears failed during endurance tests performed on the whole axles. The failure mechanisms as well as the most common approaches proposed in the literature for the evaluation of the load carrying capacity and the prevision of the lifetime of gears are commented through an analysis of the existing literature on the subject. Then the problem of the design against pitting of case hardened gears is faced from two different perspectives: on the one hand the determination of reliable endurance limits for the materials used by the suppliers of Carraro S.p.A. in the manufacturing of case hardened gears, based on a reanalysis of the database of validation tests performed in the past on the whole axles; on the other hand an experimental analysis of the pressure distribution on gear teeth during operation is reported. This latter study was useful to assess the major discrepancies between theoretical models and actual systems, in order to improve the awareness in the use of calculation software packages dedicated to the prevision of the lifetimes of gears. Finally, the development of a test rig for the contact fatigue characterization of gears materials by means of relatively fast tests on simple disc specimens is described. The first attempts to resemble the operating conditions of a particular gear pair with a dedicated design of specimens and to correlate the fatigue performances of gears and discs are discussed as well.Il lavoro descritto in questa tesi è stato sviluppato nell'ambito di un programma di apprendistato in alta formazione e ricerca in collaborazione con Carraro S.p.A., azienda leader nel mercato delle trasmissioni di potenza per veicoli “off-highway”, ovvero veicoli destinati ad uso in campo agricolo ed industriale. Lo studio è finalizzato all'analisi dei meccanismi che portano al cedimento per fatica da contatto degli ingranaggi, ed allo sviluppo di metodi affidabili ed efficienti per caratterizzare i materiali con cui vengono realizzate le ruote dentate. Il pitting è il più pericoloso tra i fenomeni di fatica da contatto a cui gli ingranaggi sono soggetti. Si manifesta con la formazione di crateri sulle superfici, che causano rumore, vibrazioni e perdita di efficienza, e può a sua volta dare luogo a danni secondari come la frattura dei denti. Le ruote solari dei riduttori epicicloidali che costituiscono lo stadio finale di riduzione delle trasmissioni fuoristrada sono particolarmente critiche dal punto di vista del pitting, essendo soggette a coppie elevate ed a condizioni di scarsa lubrificazione determinate dalla bassa velocità di rotazione. In questo lavoro, i fenomeni di fatica da contatto sono studiati sulla base della loro osservazione su ruote solari danneggiate durante i test di validazione eseguiti sugli assali completi. I meccanismi di cedimento, così come gli approcci più comuni proposti in letteratura per la valutazione della capacità di carico e la previsione della durata degli ingranaggi, sono commentati attraverso un'analisi della letteratura esistente sull'argomento. Il problema della progettazione a pitting degli ingranaggi cementati è quindi affrontato da due diversi punti di vista: in primo luogo i limiti di resistenza per i materiali utilizzati dai fornitori di Carraro S.p.A. nella produzione di ingranaggi cementati sono stati determinati sulla base di una rianalisi del database dei test di validazione eseguiti in passato gli assali completi; in secondo luogo, un'analisi sperimentale della distribuzione della pressione sui denti delle ruote solari durante il funzionamento ha permesso di valutare le principali discrepanze tra i modelli teorici e i sistemi attuali, al fine di migliorare la consapevolezza nell'uso dei pacchetti software di calcolo dedicati alla previsione della durata delle ruote dentate. Infine, viene descritto lo sviluppo di un banco di prova per la caratterizzazione della fatica da contatto di materiali per ruote dentate, mediante prove relativamente veloci su coppie di dischi di semplice ed economica realizzazione. Viene inoltre presentato l’approccio utilizzato per ricreare le condizioni operative di una particolare coppia di ruote dentate mediante un design dedicato di provini, e sono discusse le problematiche riscontrate nel tentativo di ricavare una correlazione fra le prestazioni a fatica di ingranaggi e dischi.
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Feki, Nabih. "Modélisation électro-mécanique de transmissions par engrenages : Applications à la détection et au suivi des avaries". Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00743722.
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La détection et le diagnostic des défauts d'engrenages ont été traditionnellement basés sur l'analyse des signaux vibratoires et acoustiques. Mais, ces méthodes peuvent être coûteuses suite aux difficultés techniques de mise en œuvre de capteurs sur des pièces en rotation. Dans ces travaux de thèse, une méthode originale de détection de défauts locaux dans des engrenages entraînés par des moteurs électriques est proposée en se basant sur le suivi des courants statoriques. Le système électromécanique est simulé numériquement en combinant un modèle électrique dynamique de moteurs asynchrones (modèle de Kron et modèle des réseaux de perméances) et un modèle mécanique dynamique d'engrenages droits et hélicoïdaux incluant les arbres et les paliers. Certains défauts classiques du moteur (excentricité du rotor) et des défauts d'engrenages (écaillages sur les flancs actifs de dentures) sont considérés et une technique itérative de résolution est présentée qui permet de résoudre le problème électromécanique couplé. De nombreux résultats sont présentés qui illustrent la possibilité et la sensibilité de détection de défauts d'engrenages par mesure de courants électriques sur le moteur. Sur la base de ces simulations, il est conclu que l'analyse de la signature des courants du moteur apparaît comme une méthode suffisamment précise pour détecter et surveiller les défauts locaux d'engrenage comme les écaillages.
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Kurth, Franz [Verfasser], Bernd-Robert [Akademischer Betreuer] Höhn, Ahmet [Akademischer Betreuer] Kahraman e Karsten [Akademischer Betreuer] Stahl. "Efficiency Determination and Synthesis of Complex-Compound Planetary Gear Transmissions / Franz Kurth. Gutachter: Ahmet Kahraman ; Karsten Stahl ; Bernd-Robert Höhn. Betreuer: Bernd-Robert Höhn". München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/103340313X/34.
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Chevrel-Fraux, Cyril. "Modélisation de transmissions de forte puissance : Prise en compte d'amortissements variables". Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI008.
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Travaux de thèse sont issus d’une collaboration entre la société Naval Group (anciennement DCNS) et le laboratoire du LaMCoS de l’INSA de Lyon. Dans le milieu de la propulsion navale, les transmissions par engrenages qui assurent le lien entre le moteur et l’hélice, transmettent des couples importants. Pour transmettre ces couples, les mobiles peuvent avoir de grandes dimensions (plus de deux mètres de diamètre). Pour des raisons de gains de masse, des trous ou des cavités sont généralement introduits dans le corps de la roue. L’ajout de ces alésages réduit sa masse mais augmente également sa flexibilité, ce qui peut la rendre plus apte à vibrer. Pour réduire les vibrations générées par l’engrènement sans augmenter sa masse, de nombreux travaux portent sur l’utilisation de corrections de profil et d’hélice. Une solution alternative, présentée ici, consiste à remplir le corps de la roue à l’aide d’un matériau qui peut jouer le rôle d’un amortisseur passif. Au cours de cette thèse, un modèle d’engrènement hybride a été utilisé. Dans le modèle d’engrènement à paramètres concentrés initial, les mobiles sont introduits à l’aide de disques rigides ou d’éléments de poutre de Timoshenko. Les contributions des paliers et du carter sont prises en compte via l’utilisation de paramètres concentrés. Le modèle a été adapté pour permettre l’introduction d’un modèle éléments finis de roue condensé à l’aide de méthodes de sous-structuration. La raideur d’engrènement est calculée à chaque pas de temps en fonction des conditions de contact et dans l’hypothèse de la décomposition des lignes de contact en tranches minces. Lors de la condensation du modèle éléments finis, des noeuds maîtres sont introduits dans le corps de la roue pour interagir avec le matériau de remplissage. Le matériau est supposé élastoplastique et est introduit sous la forme de paramètres concentrés. Une masse ponctuelle est positionnée au centre de chaque cavité et elle est connectée aux voiles de la roue à l’aide système de Masing. Deux interfaces successives sont utilisées lors de l’introduction du matériau de remplissage, la première intervient lors de la définition des noeuds maîtres et la deuxième lors de l’introduction du matériau pour annuler le travail des raideurs additionnelles suivant les mouvements de corps solides. Le modèle est ensuite partiellement validé numériquement. L’intérêt est porté à la fois au niveau comportement statique et dynamique à la denture, et au niveau du comportement non linéaire du matériau de remplissage. Des études à vitesses fixes ou sur des balayages en vitesse sont ensuite réalisées pour étudier les effets dissipatifs liés à l’ajout d’un matériau de remplissage. L’influence des propriétés de celui-ci, de la géométrie de la roue et des niveaux d’excitation sur le comportement dynamique de la transmission sont ensuite étudiésThis work is included in a PhD thesis in partnership between the society Naval Group and the LaMCoS laboratory at the INSA Lyon engineering school. In the naval propulsion domain, the engine is linked propeller using the gear transmission which can transmit an important torque. As a result, gears can have an important dimension, and a wheel may have a diameter of more than two meters. In order to get lighter wheel, holes and cavities can be manufactured in the body of the wheel. These cavities reduce the mass of the wheel, but it also increases its flexibility and it can generate more vibrations. To reduce vibrations without increase the gear mass, many works studied the helical and tooth profile modifications. The work is aimed to study another approach with the introduction of a filling material which can have dissipative properties in the body of the wheel in order to have a passive damper. In this work, a hybrid gear model has been used. In the initial model, the gear is a lumped parameters model, shafts are introduced with Timoshenko beams and gears are assumed to be rigid disks. Contributions of housing and bearings are introduced with lumped parameters. The model has been modified in order to introduce a condensed FE model, obtained with sub-structuring methods. The mesh stiffness is computed the thin-slice approach. During the sub-structuring step, master nodes are introduced in the body of the wheel in order to interact with the filling material. The filling material is supposed to have an elastoplastic behaviour, and it is introduced using lumped parameters. A central mass is introduced at the centre of each cavities and it is connected to webs using Masing systems. Two interfaces are used during the introduction of the filling material. The first one is used during the master nodes definition, and the second one is aimed to remove the deformation work of additional filling material during rigid body displacements. Then, the model has been validated using numerical comparisons. Output values of interest like tooth contact static and dynamic behaviour, and the non-linear behaviour of the filling material have been studied. Then, studies on a range of speed or at a single speed have been realized in order to study the dissipative effects due to the introduction of the filling material. The influence of filling material properties, gear wheel geometry, and amplitude of excitations on the gear transmission dynamic behaviour have been studied
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Hilty, Devin R. "An Experimental Investigation of Spin Power Losses of Planetary Gear Sets". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1276270638.
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Liauwnardi, Leonard. "Plastic gear transmission error measurements and predeictions". The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1407243719.
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Fish, Michael Anderson. "Transmission errors in precision worm gear drives". Thesis, University of Huddersfield, 1998. http://eprints.hud.ac.uk/id/eprint/4851/.
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Transmission error is a measure of the positioning accuracy of a gear system. This has been widely documented in gearing for many years as the source of problems in noise and vibration. It is a result of errors in the contact conditions which affect the driven gear with respect to the rotation of the driver gear. This research aims to present a better understanding of the basic kinematics of worm gear systems by identifying the significant influences which determine the contact conditions. A literature review of existing theory is described which determines the major areas considered in worm gear contact analysis. Formulae are derived which quantify the effect of component parameter variation on contact. An investigation of the design, manufacture, and operating processes is recorded which identifies error sources relative to the theoretical contact condition. A computer program is developed which calculates contact characteristics such as worm and wheel component form, transmission error and contact marking pattern for a given design including any contact error sources. Computer calculations are validated by comparing direct measurements of these characteristics from several manufactured gear sets with synthesised results produced using the design information, machine settings and error sources detected during production. The behaviour of these gear sets during operation under a torque load has been investigated experimentally. Measured transmission error data from a test rig is used to develop a basic model of worm gear deformation under load. This model has been added to the computer program to improve and extend the analysis capability. The test rig has also been used to investigate the effect of initial wear on contact characteristics. The good correlation between calculated and experimental results shows that the characteristics of a worm gear set can be predicted once all elements of the design and manufacture are known. The results also validate the software as a useful design tool for academic and industrial applications. Important conclusions are drawn on design techniques, the manufacturing process, and the effects of operating under load. Further areas of investigation are identified which offer future research an opportunity to expand upon these conclusions.
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Anichowski, Brian Jr. "An Experimental Investigation of the Effect of Spacing Errors on the Loaded Transmission Error of Spur Gear Pairs". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492619887370311.
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Košík, Matej. "Koncepční návrh převodového ústrojí pro užití v elektromobilu". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-444969.
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This diploma thesis deals with designing electric vehicle gearbox. Gearbox should serve as virtual replacement for actual transmission of VW ID.3 EV. Designed gearbox has two gears. In the first section there is an extensive search processed of drivetrain and transmission of battery electric vehicles. Next section contains choice of transmission concept and analyses solving of individual structural nodes – gear wheels, band breaks (components that engage individual gears), carriers, shaft, bearing. In the conclusion of diploma thesis, the two-gear planetary transmission is evaluated.
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Chapron, Matthieu. "Comportement dynamique de train planétaire / épicycloïdal avec erreurs d’assemblage, écarts de forme et structures déformables : Optimisation des corrections de dentures". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI040/document.
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Ces travaux de thèse sont le fruit de la collaboration entre la société Hispano-Suiza et le LaMCoS de l’INSA de Lyon. Dans le cadre du développement de nouveaux systèmes de propulsion, l’implantation d’un train planétaire / épicycloïdal entre la turbine et l’hélice semble être une voie intéressante pour atteindre les performances souhaitées en terme de rendement. L’augmentation des puissances transmises et la réduction des masses embarquées dans les applications aéronautiques tendent à rendre les composants de plus en plus déformables. Lors de ces travaux de recherche, un modèle dynamique de trains planétaires a été développé, incorporant les effets des erreurs de montage, des écarts de forme et des sous-ensembles flexibles. Une approche à paramètres concentrés est utilisée, intégrant notamment des éléments spécifiques d’engrenage et des éléments d’arbre. Pour les éléments d’engrenage, le formalisme des fines tranches juxtaposées est employé pour représenter les dentures. Une raideur élémentaire et un écart normal sont attribués à chacune des tranches et sont réactualisés à chaque pas de temps en fonction de la cinématique des composants et des déviations du profil des dentures. Les déformations de la couronne sont introduites à l’aide d’un anneau discret composé de poutres droites couplé aux éléments d’engrenage. Les dentures double-hélice sont modélisées par deux éléments d’engrenage d’angles d’hélice opposés liés par une poutre de Timoshenko. Finalement, les équations du mouvement sont résolues pas à pas dans le temps par un schéma de Newmark combiné à un algorithme de contact normal, permettant de prendre en compte les pertes de contact partielles ou complètes. Dans un premier temps, un certain nombre d’éléments de validation est présenté et comparé à des résultats tirés de la littérature. Afin d’asseoir notre modélisation, l’influence des erreurs de positionnement des satellites, du décalage des hélices, des erreurs de pas et des déformations de la couronne sur les distributions de charge est abordée pour différentes configurations de train planétaire. Dans un deuxième temps, l’optimisation des corrections de denture dans le but de réduire les vibrations est investiguée. Les corrections de profil sont introduites sur les engrènements de façon (i) linéaire et symétrique en tête de dents et (ii) identique pour tous les satellites mais (iii) différente selon le flanc actif. Dans ce contexte, les corrections sont tout d’abord optimisées vis-à-vis des efforts dynamiques d’engrènement à l’aide d’un algorithme génétique. Puis, leurs performances sont analysées en fonction du couple transmis et de la vitesse de rotation. Par la suite, un critère « équivalent » est dérivé, vérifié et utilisé pour étudier l’influence du décalage des hélices et d’une correction longitudinale parabolique sur ces corrections de profil optimales. Enfin, une sous-structure du porte-couronne est introduite et son impact sur les distributions de charge est exploréThis research work was conducted at the Contact and Structural Mechanics Laboratory (LaMCoS) of LaMCoS - INSA Lyon (UMR CNRS 5259) in partnership with Hispano-Suiza (SAFRAN group). In the context of new turbo jet engine developments, a promising technological solution consists in inserting a planetary / epicyclic gear train between the turbine and the propeller which, in theory, can improve the system performance, especially in terms of efficiency. Increasing power densities and mass reduction constraints lead to more compliant structures which need to be analyzed from a dynamic viewpoint. The present work deals therefore with the dynamic modelling of planetary / epicyclic gears and the effects of assembly errors, tooth shape deviations and deformable structural components. A lumped parameter approach has been favored which combines rigid-body gear elements, beam and lumped parameters elements. A thin-slice model has been used to simulate the time-varying elastic properties of gear teeth with an elemental stiffness and a normal deviation functions attributed to every discrete cell on the contact lines (thin slice) and updated at each time step with respect to the meshing course and the instant positions of the teeth. Ring-gear deformations are introduced via a model of elastic annulus discretized into straight beam elements and connected to the gear elements. Double-helical gears are simulated by linking two gear elements of opposite hands by Timoshenko beam elements. The possibility of helix stagger is implemented by shifting the helix positions in the base plane. Finally, the equations of motion are solved step by step in time by combining a Newmark scheme and a normal contact algorithm which makes it possible to account for partial and total instant contact losses. A number of comparisons with benchmark results from the literature are presented which prove that the proposed theoretical and numerical developments are sound and can actually be used to simulate the influence of planet position errors, helix stagger, pitch errors and ring-gear deformations. The optimization of tooth shape modifications, i.e. profile and lead modifications, re dynamic mesh forces in planetary gears is tackled. Using a genetic algorithm, optimum profile modifications are derived and compared with some analytical results in the literature. Their performance over a range of loads and speeds is assessed for helical and double helical gears with rigid and flexible ring-gears. A quasi-static “equivalent” criterion based on local transmission errors is presented and commented upon. Having proved its relevance, a number of results are derived concerning the influence of helix stagger and lead crowning superimposed on optimum profile modifications. Finally, a deformable ring-gear support is introduced using a sub-structuring technique and its contribution in terms of tooth load distribution is examined
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Mehdi, Pour Reza. "Transmission DynamicsModelling : Gear Whine Simulation Using AVL Excite". Thesis, KTH, Fordonsdynamik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-243090.
Texto completo da fonteResumo:
Nowadays, increasing pressure from legislation and customer demands in the automotive industry are forcing manufacturers to produce greener vehicles with lower emissions and fuel consumption.As a result, electrified and hybrid vehicles are a growing popular alternative to traditional internal combustion engines (ICE). The noise from an electric vehicle comes mainly from contact between tyres and road, wind resistance and driveline. The noise emitted from the driveline is for the mostpart related to the gearbox. When developing a driveline, it is a factor of importance to estimate the noise radiating from the gearbox to achieve an acceptable design.Gears are used extensively in the driveline of electric vehicles. As the gears are in mesh, a main intrusive concern is known as gear whine noise. Gear whine noise is an undesired vibroacoustic phenomenon and is likely to originate through the gear contacts and be transferred through themechanical components to the housing where the vibrations are converted into airborne and structure-borne noise. The gear whine noise originates primarily from the excitation coming from transmission error (TE). Transmission error is defined as the difference between the ideal smoothtransfer of motion of a gear and what is in practice due to lack of smoothness.The main objective of this study is to simulate the vibrations generated by the gear whine noise in an electric powertrain line developed by AVL Vicura. The electric transmission used in this study provides only a fixed overall gear ratio, i.e. 9.59, under all operation conditions. It is assumed thatthe system is excited only by the transmission error and the mesh stiffness of the gear contacts. In order to perform NVH analysis under different operating conditions, a multibody dynamics model according to the AVL Excite program has been developed. The dynamic simulations are thencompared with previous experimental measurements provided by AVL Vicura.Two validation criteria have been used to analyse the dynamic behaviour of the AVL Excite model: signal processing using the FFT method and comparison with the experimental measurements.The results from the AVL Excite model show that the FFT criterion is quite successful and all excitation frequencies are properly observed in FFT plots. Nevertheless, when it comes to the second criterion, as long as not all dynamic parameters of the system such as damping or stiffnesscoefficients are provided with certainty in the model, it is too difficult to investigate the accuracy of the AVL Excite model. Another investigation is a numerical design study to analyses how the damping coefficients influence the response. After reducing the damping parameters, the results show that the housing and bearings have the highest influence on the response. If more acceptable results are desired,future studies must be concentrated on these to obtain more acceptable damping values.För närvarande tvingar ökat tryck från lagstiftning och kundkrav inom bilindustrin tillverkarna attproducera grönare fordon med lägre utsläpp och bränsleförbrukning. Som ett resultat ärelektrifierade och hybridfordon ett växande populärt alternativ till traditionellaförbränningsmotorer (ICE). Bullret från ett elfordon kommer främst från kontakten mellan däckoch väg, vindmotstånd och drivlinan. Bullret från drivlinan är i huvudsak relaterat till växellådan.Vid utveckling av en drivlina är det av betydelse att uppskatta bullret från växellådan för att uppnåen acceptabel design.Utväxlingar används i stor utsträckning i elfordons drivlina. Eftersom kugghjulen är i kontaktuppstår ett huvudproblem som är känt som ett vinande ljud från kugghjulskontakten.Kugghjulsljud är ett oönskat vibro-akustiskt fenomen och uppstår sannolikt på grund avkugghjulkontakterna och överförs via de mekaniska komponenterna till växellådshuset därvibrationerna omvandlas till luftburet och strukturburet ljud. Kugghjulsljudet härstammarhuvudsakligen från exciteringen som kommer från transmissionsfel (TE) i kugghjulskontakten.Överföringsfelet definieras som skillnaden mellan den ideala smidiga rörelseöverföringen hoskugghjulen och rörelsen som sker i verkligheten på grund av ojämnheter.Huvudsyftet med denna studie är att simulera vibrationerna som genereras avkugghjulskontakterna i en elektrisk drivlina utvecklad av AVL Vicura. Den elektriska drivlinan somanvänds i denna studie har endast ett fast utväxlingsförhållande, dvs 9,59, för alladriftsförhållanden. Det antas att systemet är exciterat endast av överföringsfelet och kugghjulensstyvhet i kuggkontakterna. För att kunna utföra NVH-analys under olika driftsförhållanden har enstelkroppsdynamikmodell utvecklats med hjälp av programmet AVL Excite. De dynamiskasimuleringarna jämförs sedan med tidigare experimentella mätningar som tillhandahålls av AVLVicura.Två valideringskriterier har använts för att analysera det dynamiska beteendet hos AVL Excitemodellen:signalbehandling med FFT-metoden och jämförelse med experimentella mätningar.Resultaten från AVL Excite-modellen visar att FFT-kriteriet är ganska framgångsrikt och allaexcitationsfrekvenser observeras korrekt i FFT-diagrammen. Men när det gäller det andra kriteriet,så länge som inte alla dynamiska parametrar i systemet, såsom dämpnings- ellerstyvhetskoefficienter, är tillförlitliga i modellen, är det för svårt att undersöka exaktheten hos AVLExcite-modellen.En annan undersökning som utförts är en numerisk designstudie för att analysera hurdämpningskoefficienterna påverkar responsen. Efter minskning av dämpningsparametrarna visarresultaten att växellådshus och lager har störst inflytande på resultatet. Om mer acceptabla resultatär önskvärda måste framtida studier koncentreras på dessa parametrar för att uppnå mer acceptabladämpningsvärden.
21
Boguski, Brian C. "An Experimental Investigation of the System-Level Behavior of Planetary Gear Sets". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1291009879.
Texto completo da fonte
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Mehdi, Pour Reza. "Transmission Dynamics Modelling : Gear Whine Simulation Using AVL Excite". Thesis, KTH, Fordonsdesign, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-234817.
Texto completo da fonteResumo:
Nowadays, increasing pressure from legislation and customer demands in the automotive industryare forcing manufacturers to produce greener vehicles with lower emissions and fuel consumption.As a result, electrified and hybrid vehicles are a growing popular alternative to traditional internalcombustion engines (ICE). The noise from an electric vehicle comes mainly from contact betweentyres and road, wind resistance and driveline. The noise emitted from the driveline is for the mostpart related to the gearbox. When developing a driveline, it is a factor of importance to estimatethe noise radiating from the gearbox to achieve an acceptable design.Gears are used extensively in the driveline of electric vehicles. As the gears are in mesh, a mainintrusive concern is known as gear whine noise. Gear whine noise is an undesired vibroacousticphenomenon and is likely to originate through the gear contacts and be transferred through themechanical components to the housing where the vibrations are converted into airborne andstructure-borne noise. The gear whine noise originates primarily from the excitation coming fromtransmission error (TE). Transmission error is defined as the difference between the ideal smoothtransfer of motion of a gear and what is in practice due to lack of smoothness.The main objective of this study is to simulate the vibrations generated by the gear whine noise inan electric powertrain line developed by AVL Vicura. The electric transmission used in this studyprovides only a fixed overall gear ratio, i.e. 9.59, under all operation conditions. It is assumed thatthe system is excited only by the transmission error and the mesh stiffness of the gear contacts. Inorder to perform NVH analysis under different operating conditions, a multibody dynamics modelaccording to the AVL Excite program has been developed. The dynamic simulations are thencompared with previous experimental measurements provided by AVL Vicura.Two validation criteria have been used to analyse the dynamic behaviour of the AVL Excite model:signal processing using the FFT method and comparison with the experimental measurements.The results from the AVL Excite model show that the FFT criterion is quite successful and allexcitation frequencies are properly observed in FFT plots. Nevertheless, when it comes to thesecond criterion, as long as not all dynamic parameters of the system such as damping or stiffnesscoefficients are provided with certainty in the model, it is too difficult to investigate the accuracy ofthe AVL Excite model.Another investigation is a numerical design study to analyses how the damping coefficientsinfluence the response. After reducing the damping parameters, the results show that the housingand bearings have the highest influence on the response. If more acceptable results are desired,future studies must be concentrated on these to obtain more acceptable damping values.För närvarande tvingar ökat tryck från lagstiftning och kundkrav inom bilindustrin tillverkarna attproducera grönare fordon med lägre utsläpp och bränsleförbrukning. Som ett resultat ärelektrifierade och hybridfordon ett växande populärt alternativ till traditionellaförbränningsmotorer (ICE). Bullret från ett elfordon kommer främst från kontakten mellan däckoch väg, vindmotstånd och drivlinan. Bullret från drivlinan är i huvudsak relaterat till växellådan.Vid utveckling av en drivlina är det av betydelse att uppskatta bullret från växellådan för att uppnåen acceptabel design.Utväxlingar används i stor utsträckning i elfordons drivlina. Eftersom kugghjulen är i kontaktuppstår ett huvudproblem som är känt som ett vinande ljud från kugghjulskontakten.Kugghjulsljud är ett oönskat vibro-akustiskt fenomen och uppstår sannolikt på grund avkugghjulkontakterna och överförs via de mekaniska komponenterna till växellådshuset därvibrationerna omvandlas till luftburet och strukturburet ljud. Kugghjulsljudet härstammarhuvudsakligen från exciteringen som kommer från transmissionsfel (TE) i kugghjulskontakten.Överföringsfelet definieras som skillnaden mellan den ideala smidiga rörelseöverföringen hoskugghjulen och rörelsen som sker i verkligheten på grund av ojämnheter.Huvudsyftet med denna studie är att simulera vibrationerna som genereras avkugghjulskontakterna i en elektrisk drivlina utvecklad av AVL Vicura. Den elektriska drivlinan somanvänds i denna studie har endast ett fast utväxlingsförhållande, dvs 9,59, för alladriftsförhållanden. Det antas att systemet är exciterat endast av överföringsfelet och kugghjulensstyvhet i kuggkontakterna. För att kunna utföra NVH-analys under olika driftsförhållanden har enstelkroppsdynamikmodell utvecklats med hjälp av programmet AVL Excite. De dynamiskasimuleringarna jämförs sedan med tidigare experimentella mätningar som tillhandahålls av AVLVicura.Två valideringskriterier har använts för att analysera det dynamiska beteendet hos AVL Excitemodellen:signalbehandling med FFT-metoden och jämförelse med experimentella mätningar.Resultaten från AVL Excite-modellen visar att FFT-kriteriet är ganska framgångsrikt och allaexcitationsfrekvenser observeras korrekt i FFT-diagrammen. Men när det gäller det andra kriteriet,så länge som inte alla dynamiska parametrar i systemet, såsom dämpnings- ellerstyvhetskoefficienter, är tillförlitliga i modellen, är det för svårt att undersöka exaktheten hos AVLExcite-modellen.En annan undersökning som utförts är en numerisk designstudie för att analysera hurdämpningskoefficienterna påverkar responsen. Efter minskning av dämpningsparametrarna visarresultaten att växellådshus och lager har störst inflytande på resultatet. Om mer acceptabla resultatär önskvärda måste framtida studier koncentreras på dessa parametrar för att uppnå mer acceptabladämpningsvärden.
23
Wang, Hong. "MACHINE HEALTH MONITORING OF ROTOR-BEARING-GEAR TRANSMISSION SYSTEM". University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1133281063.
Texto completo da fonte
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Alshahrany, Shaya. "Rolling contact fatigue in heavily loaded gear transmission contacts". Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/90422/.
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This thesis examines the influence of asperities such as found on the teeth of gears and discs, and failure mechanisms associated with rough surface Elastohydrodynamic Lubrication (EHL). The principal outcomes of the research provide a good insight into fatigue life, residual stress effects, damage prediction and surface contact failures. In particular, the study is intended to provide understanding into the residual stress distribution resulting from plastic deformation of surface asperities in the running in process. The residual stress is then added to the asperity elastic stress distribution and examined in detail to see the effects on fatigue damage and fatigue life. So, a theoretical model has been developed to assist design against the residual stress effect and surface contact fatigue, such as micropitting. The technique used in the study starts with developing an elastic plastic model of the rough surface by using the Abaqus Finite Element analysis software package. This is a nonlinear problem and ranges of applied loads have been applied to the as-manufactured surfaces causing the asperity features to experience varying degrees of plastic deformation. The pre and post running roughness profiles are studied in order to assess the level of plastic deformation actually occurring at significant surface asperity features by aligning the pre and post running profiles. This results in a new technique that has helped to identify the level of plastic deformation occurring in the practice, and also to make a comparison with FEA contact analysis for the same asperity features to identify the appropriate residual stress field. The residual stress field associated with the plastic deformation was extracted and evaluated. The extracted residual stress field was transferred to a form that facilitated IV inclusion in stress evaluation code to obtain the stress history for the material subject to loading in an EHL contact. The research carried out considers surface fatigue analysis with and without a residual stress field, so as to establish the influence of asperity plastic deformation on the fatigue properties of the surface. All the work is based on numerical simulation of surface fatigue failure in EHL situations and carried out numerically. The procedure can be applied quickly and gives the opportunity to apply several models and investigate the influence of all the model parameters on material deformation and fatigue life.
25
Fakhfakh, Hassen. "Etude du comportement dynamique d’un système multi-étages à engrènements en cascade et décalés à dentures droites et hélicoïdales - Optimisation des corrections de profil". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI071/document.
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Ce travail de thèse, réalisé dans le cadre d’une collaboration avec la société Hispano-Suiza (groupe SAFRAN) porte sur la modélisation et l’analyse des vibrations et surcharges dynamiques sur les engrènements d’un réducteur aéronautique multi-étage constitué de plusieurs cascades d’engrènements situés dans des plans décalés. Une modélisation originale est proposée qui repose sur le couplage entre la résolution des équations du mouvement et la prise en compte des conditions de contact instantanées sur l’ensemble de tous les engrènements. Le modèle gère les phases relatives entre engrènements ainsi que l’influence des modifications de corrections de forme des dentures. En s’appuyant sur de nombreux exemples d’application, il est montré que des corrections de profil linéaires et symétriques adaptées permettent d’abaisser très sensiblement le niveau de surcharges dynamiques sur une plage de vitesse de rotation importante. Il est également confirmé que les efforts dynamiques sur les engrènements sont fortement corrélés aux amplitudes des variations temporelles des erreurs de transmission locales pour un fonctionnement quasi-statique sous charge. Considérant différentes architectures de transmissions, des optimisations conduites grâce à un algorithme génétique montrent que les paramètres optimaux de corrections de profil sont à choisir au voisinage d’une ‘courbe maîtresse modifiée’, initialement définie pour un seul engrènement et dont les propriétés semblent pouvoir être extrapolées à des systèmes avec plusieurs engrènements simultanés. Les résultats de simulations prouvent que l’ensemble des corrections sélectionnées sur les courbes maîtresses modifiées améliorent sensiblement le comportement dynamique des systèmes d’engrenages multi-étages. En revanche, pour des systèmes soumis à des niveaux de charge différents, des corrections optimales courtes semblent plus adaptées en termes de dynamique de l’engrènement tandis que des corrections optimales longues semblent plus efficaces en ce qui concerne le niveau de contraintes en pied de dentsThis research work, conducted in cooperation with Hispano-Suiza (SAFRAN group), is focused on the modelling and analysis of vibrations and dynamic loads in aeronautical multi-mesh gears comprising several spatial gear arrangements (idler gears, several pinions on one shaft). An original model is presented which relies on the simultaneous solution of the equations of motion and the instant contact conditions for all the tooth contacts and all the meshes. The phasing between the various meshes along with tooth shape modifications are integrated in the simulations. Based on a number of simulation results, it is shown that linear symmetric profile modifications can substantially reduce dynamic tooth loads over of broad range of speeds. It is also confirmed that dynamic mesh forces are strongly correlated with the time-variations amplitudes of local quasi-static transmission errors under load. Considering several gear arrangements, tooth profile optimisations have been performed using a genetic algorithm which indicate that optimum reliefs always lie in the vicinity of the so-called ‘modified Master Curve’ initially defined for a single pinion-gear pair. This finding suggests that the concept of Master Curve can probably be extended to more complex gear systems. The simulation results prove that all the optimal profile modifications on the Master Curve improve the dynamic tooth loading conditions in multi-mesh gears. However, for systems submitted to several load levels, short optimal reliefs seem preferable whereas long optimal reliefs are more effective in terms of root stresses
26
Karmi, Bilel. "Fiabilité et optimisation des systèmes mécaniques : applications aux éoliennes". Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMLH12.
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Le comportement dynamique des systèmes mécaniques est crucial dans l'industrie pour éviter l'instabilité et les vibrations, assurant ainsi la fiabilité et la durabilité des équipements. La complexité et les incertitudes inhérentes rendent la modélisation précise difficile, mais intégrer ces incertitudes est essentiel pour renforcer la robustesse des systèmes. Des approches comme la simulation de Monte Carlo sont utilisées pour tenir compte de ces incertitudes, notamment dans des domaines spécifiques comme les transmissions par engrenage, où les paramètres incertains peuvent avoir un impact significatif sur le comportement dynamique. En résumé, comprendre et gérer les incertitudes dans la conception des systèmes mécaniques contribue à améliorer leur performance et leur fiabilité dans des environnements opérationnels variés.En outre, une compréhension approfondie des dynamiques mécaniques permet d'anticiper les zones de fragilité et de minimiser les risques de défaillance, ce qui est essentiel pour garantir la sécurité et la performance des équipements industriels. Les ingénieurs doivent adopter une approche proactive pour relever les défis liés à la conception de systèmes mécaniques fiables, en tenant compte des incertitudes liées à des facteurs tels que les forces de frottement, les raideurs des engrenages et les conditions environnementales changeantes. La modélisation stochastique, telle que la simulation de Monte Carlo, offre des outils précieux pour évaluer et atténuer les risques associés à ces incertitudes, assurant ainsi une conception plus robuste et une meilleure performance des systèmes mécaniques dans diverses conditions d'exploitationThe dynamic behavior of mechanical systems is crucial in industry to avoid instability and vibrations, ensuring the reliability and durability of equipment. The inherent complexity and uncertainties make precise modeling challenging, but incorporating these uncertainties is essential to strengthen system robustness. Approaches such as Monte Carlo simulation are used to account for these uncertainties, particularly in specific areas like gear transmissions, where uncertain parameters can significantly impact dynamic behavior. In summary, understanding and managing uncertainties in the design of mechanical systems contributes to improving their performance and reliability in various operational environments.Furthermore, a thorough understanding of mechanical dynamics allows anticipating weak areas and minimizing failure risks, essential for ensuring the safety and performance of industrial equipment. Engineers must take a proactive approach to address challenges in designing reliable mechanical systems, considering uncertainties related to factors such as friction forces, gear stiffness, and changing environmental conditions. Stochastic modeling, such as Monte Carlo simulation, provides valuable tools to assess and mitigate risks associated with these uncertainties, thereby ensuring more robust design and better performance of mechanical systems in diverse operating conditions
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Bagge, Mats. "An approach for systematic process planning of gear transmission parts". Licentiate thesis, KTH, Production Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9942.
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The objective of this thesis is to find and develop methods that enhance and support the creation of evolvable master process plans with possibilities to challenge productivity and meet changing design requirements. The condition for achieving this is primarily that both the fundamental thinking and the results behind a process plan can be described. How should this be done?
The focus is laid on process planning of gear transmission parts for heavy vehicles like trucks and coaches.
Process planning is the activity where design and manufacturing are brought together with the common target to achieve both a competitive product and production process. There are many factors that influence the process planner when a new product or process shall be introduced for production. Process planning is, in most cases, performed by an experienced, skilled person but without any defined methodology or way of working. Much of the process planning is based on the retrieval of solutions already used.
Much research effort has been devoted to developing systems for computer-aided process planning (CAPP). Yet CAPP systems have not been accepted and spread over a wide front within the manufacturing industry, much because of the functional incompleteness combined with the difficulties of adopting knowledge and changing requests.
A method for systematic process planning is proposed as a way to perform and describe the procedure of creating a process plan. The method facilitates the interpretation and understanding of the plan, not only immediately for the process planner responsible, but also for designers, engineers, researchers and other interest groups involved in a manufacturing process.
In the last chapter is a case study regarding manufacturing of a bevel gear pinion presented to exemplify use of the proposed method for systematic process planning.
KUGG
28
Tangasawi, Osman A. M. "Combined numerical and experimental investigation of transmission idle gear rattle". Thesis, Loughborough University, 2007. https://dspace.lboro.ac.uk/2134/16553.
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Gear rattle is caused by engine torsional vibration (engine order response) imparted to the transmission components, further causing the gears to oscillate within their functional backlashes. These oscillations lead to the repetitive impact of gear teeth, which lead to noisy responses, referred to as gear rattle. The lack of in-depth research into the effect of lubricant on gear rattle has been identified as a deficiency in the previous research in rattle. The aim ofthe current work is to address this shortcoming. The thesis outlines a new approach in investigating the problem of idle gear rattle. The approach is based on the assumption that under idling condition the teeth-pair impact loads are sufficiently low and the gear speeds are sufficiently high to permit the formation of a hydrodynamic lubricant film between the mating gear teeth. This film acts as a non-linear spring-damper that couples the driver and the driven gears. A torsional single-degree of freedom model is used in the development of the theory. The model is then expanded into a seven-degree of freedom torsional model and finally into an Il-degree of freedom model that also includes the lateral vibrations of the supporting shafts. The Il-degree of freedom model is based on a real life transmission that is also used in experimental studies to validate the model. It is found that lubricant viscosity and bearing clearance (lubricant resistance in squeeze) play important roles in determining the dynamics of the system and its propensity to rattle. At low temperatures, the lateral vibrations of the shafts, carrying the gears interfere with the gear teeth impact action. The severity of rattle is determined by the relationship between the entraining and squeeze film actions of the hydrodynamic film. When the latter dominates, the system can rattle more severely. The numerical results are found to correlate well with the experimental findings obtained from vehicle tests in a semi-anechoic chamber and also with those from a transmission test rig in the powertrain laboratory.
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Sweeney, Katelyn (Katelyn M. ). "Development of a gear shift test setup for hybrid transmission vehicles". Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119935.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 39-40).
As fuel and efficiency regulations tighten, precise and highly efficient transmission systems are becoming necessities. Previous studies at the MIT Global Engineering and Research (GEAR) Laboratory demonstrated mathematically the ability to improve the shift event via Hall Effect sensing; this study sought to implement those results in practice. To accomplish this, measurements of the physical gearsets, motors, and actuators were implemented into Computer Aided Design (CAD) software in order to design mounts and fixtures. Those mounts and fixtures were then manufactured and implemented into the real setup. In addition, brushless DC motors were utilized and tailored to drive the transmission. The end result was both CAD and physical assemblies that are simple, easy to assemble, and precise to the specifications of the experiment. From this study a proof-of-concept was built, showing that it is indeed possible spatially and physically to build an effective test setup that can support the theoretical needs of the experiment.
by Katelyn Sweeney.
S.B.
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Tuttle, Timothy Douglas. "Understanding and modeling the behavior of a harmonic drive gear transmission". Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12789.
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Kwon, Hyun Sik. "Development of Automated Design Tools for Automotive Automatic Transmission Gear System". The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1370019857.
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Öun, Martin. "Automatic Transmission Power Flow Matrix Representation". Thesis, KTH, Maskinkonstruktion (Inst.), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-157471.
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The project has worked with the function and structure of epicyclical automatic transmissions. The goal of the project has been to find a mathematical way of representing the transmissions setup and possible power flows. Furthermore the project has included the generation of all theoretically possible matrix representations of two simple planetary gear sets in MATLAB as the base for a future optimization model. The result of the project is a large quantity of matrix representations of the two planetary gear sets and their connections and shafts. The result from the MATLAB program has been verified by comparing the structure and the number of solutions to all manually derived setups. The result from the program can be considered to be complete for two planetary gears but to extend the analysis to more complex planetary gears and gearboxes with more than two sets, another method is suggested. The generation process in this project has been rather complex and time consuming. The conclusions drawn from this project is that it is possible to represent many epicyclical automatic transmissions in matrix form. An optimization program based on this type of matrix would simplify the design of new, more complex and more efficient epicyclical transmissions leading to more efficient vehicles. Key words: automatic transmission, planetary gear, matrix representationProjektet har behandlat epicykliska automatväxellådor och dess uppbyggnad och funktion. Idén med projektet har varit att ta fram ett sätt för att på ett matematiskt sätt representera växellådans struktur och dess möjliga effektflöden. Utöver detta har arbetet inneburit att alla teoretiskt möjliga matrisrepresentationer för två enkla sammankopplade planetväxlar har tagits fram i MATLAB som underlag för en framtida optimeringsmodell. Resultatet av arbetet är en stor mängd uppställningar av dessa två planetväxlar och dessas sammankopplingar. Resultatet från MATLAB har jämförts och verifierats genom manuell beräkning av antalet variationer och dessas utseende. Resultatet från programmet kan anses som komplett men för en utökad analys av epicykliska automatväxellådor med fler än två planetväxlar och andra typer än den enklaste formen av planetväxel, rekommenderas en annan typ av framställning av alla möjliga variationer. Den metoden för att generera sammankopplingar som har använts i detta projekt är för komplex och tidskrävande. Slutsatsen av projektet är att det finns möjlighet att generera och representera många epicykliska automatväxellådor på matrisform. Ett optimeringsprogram baserat på denna typ av matris kan förenkla utvecklingen av nya mer avancerade och mer effektiva epicykliska automatväxelådor vilket leder till mer effektiva fordon. Nyckelord: automatisk växellåda, planetväxel, matrisrepresentation
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Milliren, Mark R. "AN EXPERIMENTAL INVESTIGATION INTO THE INFLUENCE OF VARIOUS ERRORS ON THE TRANSMISSION ERROR AND ROOT STRESSES OF SPUR GEARS". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1314209495.
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Haupt, Brandon Levi. "Design and Analysis of a Positively Engaged Continuously Variable Transmission". Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2635.pdf.
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Janzen, Isaiah. "Modeling of Heat Treating Processes for Transmission Gears". Digital WPI, 2009. https://digitalcommons.wpi.edu/etd-theses/1123.
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"The effects of heat treating process parameters on the microstructure, residual stress, and distortion of a vacuum carburized, quenched and cold treated ring gear made of Pyrowear 53 has been determined using Abaqus and DANTE software. The data from these finite element method simulations was compared to measured values from physical testing. It was found that the heat treating process of the ring gear could be simulated and provide similar results to the measured and specified values for hardness, carbon content, and distortion. The simulations and distortion in this paper provide a detailed view of the mass transfer, heat transfer, and stress that occur during heat treating. These simulations suggest nonuniform cooling of a ring gear leads to greater distortion than uniform cooling. Simulations compared the retained austenite and hardness in ring gears that were oil quenched and high pressure gas quenched."
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Li, Zheng. "Spur gear teeth contact analysis on power-train transmission noise, vibration and harshness". Thesis, University of Warwick, 2009. http://wrap.warwick.ac.uk/3163/.
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The gear meshing is very complex process as high non-linearity behaviour is involved during the process. Normally most analysis of gear tooth contact is on the basis of a hypothesis that the contacted gear teeth are cantilever beams to obtain the approximate results quickly. However, many important factors have been ignored in simulating gear tooth contact using cantilever beam hypothesis, those factors include tooth profile variations, gear rotation speed and input torque, coefficient of friction and geometry distortion. Many of non-linear responses such as noise, vibration, abrasion and so on make the actual contact process much more complicated than those in the cantilever beam hypothesis although it is a reliable reference for integrated gear performance investigation. The main contribution of this thesis is in the investigation of the typical static and dynamic performances of meshing gears by simulating gears rolling-sliding contact processes using non-linear finite element method. A typical spur gear model has been proposed first for performance analysis and the model with integrated parameters could contribute reliable finite element conditions to simulate actual gear meshing. The bending stress and its resultant stress of contacted teeth with static model and dynamic model have been then simulated and the results can be used to provide information on the contacted teeth stresses distribution. The detailed investigation of transmission error in gear meshing has been carried out to understand harmful noise and vibration of gear set and a micro geometry modification of gear tooth profile has been proposed, i.e. tip relief. The gear contact pressure distributions and transmission errors have been then analyzed with micro geometry modification and the analysis is under static and dynamic boundary conditions. Finally, the most significant contribution of the thesis is the investigation of the frictional effect on dynamic performance, including dynamic stress and transmission errors.
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DESAI, KAUSHIK. "Oil Churning losses in Automatic Transmission". Thesis, KTH, Maskinkonstruktion (Inst.), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-141768.
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Lately the discussion on how big impact vehicles has on the environment has grown bigger and bigger. The vehicle manufacturers are building cars, trucks, and wheel loaders etc. that are getting more and more fuel efficient for every year. But where do the engineers at the companies make the improvements? The drive train is one area of the vehicle where many different sources of losses are found. The gearbox is one example, where the losses are both dependent and independent on the torque transferred by the gear pairs. The gearbox consists of several components that all of them contribute to the total system power loss. It is therefore of great interest to understand the magnitude of the losses in the gears, for different operating conditions, and also to be able to determine how they change with, for instance, rotational speed, oil viscosity. The goal of the master thesis was to make a study about the oil churning losses in a 6 speed automatic gearbox. This model makes use of calculations which were based on scientific experiments. This makes the loss calculations more advanced and accurate than the generalized formulas in most commercial software’s. This model takes into account only the oil churning and oil pocketing losses and shall not hold account for the windage losses or the other losses such as losses occurring due to bearings, seals, pumps etc. Due to time constraint a user friendly programme could not be written but the generated programme can be modified to make it easier for the user to input the data and produce results. All gears are modelled in simple modules built using MATLAB m-codes. Assumptions are made in the code when it came to choosing the oil viscosity.På senare år har diskussionen om fordonens miljöpåverkan blivit allt mer intensiv. Fordonstillverkarna bygger bilar, lastbilar, hjullastare, etc., vars bränsleeffektivitet årligen når nya höjder. Var finns utrymme för förbättringar? Drivlinan är en del av fordonet där många olika förlustkällor påträffas; t.ex. växellådan, där förlusterna både är beroende och oberoende av det vridmoment som överförs av kugghjulsparen. Växellådan består av ett flertal komponenter som bidrar till systemets totala effektförlust. Det är därför av stort intresse att förstå omfattningen av förlusterna i kugghjulen, för olika driftsförhållanden, och att kunna bestämma hur förlusterna är relaterade till t.ex. rotationshastighet och oljeviskositet. Målet med examensarbetet var att göra en undersökning om oljeskvalpförluster (”oil churning losses”) i en 6-växlad automatlåda. Modellen använder beräkningar baserade på vetenskapliga experiment. Detta gör förlustberäkningarna mer avancerade och exakta än de allmänna formler som de flesta kommersiella programvaror nyttjar. Modellen tar endast hänsyn till oljeskvalpförluster och oljeficksförluster (”oil pocketing losses”) och tar icke hänsyn till vindförluster eller andra förluster såsom lagerförluster, friktion i tätningar, pumpförluster, etc. På grund av projektets tidsramar har förfiningen av programmets användargränssnitt prioriterats lågt; vid behov kan detta åtgärdas för att förenkla input och output av data. Alla kugghjul modelleras i enkla moduler som byggts som MATLAB-skript. Antaganden görs i koden när det gäller oljans viskositet .
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Henriksson, Mats. "On Noise Generation and Dynamic Transmission Error of Gears". Doctoral thesis, KTH, Farkost och flyg, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11858.
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Noise from heavy trucks is an important environmental issue. Several sources contribute to the total noise level of a vehicle, such as the engine, gearbox, tires, etc. The tonal noise from the gearbox can be very disturbing for the driver, even if the noise level from the gearbox is lower than the total noise level. The human ear has a remarkable way of detecting pure tones of which the noise from loaded gears consists of. To be allowed to sell a heavy truck within the European Union, the so called pass-by noise test must be completed successfully. The maximum noise level permitted is 80dB(A) and undercertain conditions, the gearbox can be an important contributor to the total noise level. Gear noise is therefore an important issue for the automotive industry. In this thesis gear noise and dynamic transmission error is investigated. Traditionally, transmission error (TE) is considered to be the main excitation mechanism of gear noise. The definition of TE is ”the difference between the actual position of the output gearand the position it would occupy if the gear drive were perfect”. Measurements of dynamic transmission error (DTE) and noise have been performed on a gearbox. The measurement object was a commercial truck gearbox powered by an electrical motor. The torque used was in the normal operating range of the gearbox and the correlation between gear noise and DTE, when the torque is changed, is investigated. The result differs for different gear pairs and for the first gear stage, located close to the housing, the correlation is high for most speeds. The measured DTE and noise show a poor correlation with calculated transmission error. A minimisation of TE therefore does not necessarily mean a minimisation of gear noise. A transfer function can be employed to calculate the relationship between DTE and noise. The general trend of the gear noise is an increase of 6dB per doubling of the rotational speed together with fluctuations around the mean due to resonances of the system. The magnitude of the transfer function can be estimated using the amplitudesof the gear mesh orders and harmonics. Two gear pairs with similar macro geometry but different profile modifications are investigated. Although the gear pairs have similar transmission error, the noise level display a significantly different trend, further strengt hening the position that transmission error is not the single most important gear noise excitation mechanism. Further analysis concludes that shuttling forces and friction forces can be more important than what is often suggested. A dynamic model including transmission error and shuttling forces is used to investigate the two gear pairs. The bearing forces show that for some frequency regions shuttling forces can be of the same order of magnitude as the forces caused by transmission error. This work highlights the importance of considering other excitations of gear noise besides transmission error when designing quiet gears. The influence of transmission error can not be determined by investigating the gears only. A deeper knowledge of the gear system is needed in order to minimise gear noise for a specific gear design.QC 20100719
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LIN, PO-YUAN, e 林伯原. "Research of Hypocycloidal Gear Transmissions". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/4j957s.
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碩士吳鳳科技大學
光機電暨材料研究所
106
The objective of this research is to push the Electro-Mechanical (EM) actuator technology forward and make it capable of meeting increasingly demanding requirements by improving gear transmission technology which has the most significant effects on actuator performance. The research presents in-depth parametric design and analysis of the Hypocycloidal Gear Transmission (HGT). Careful parametric design of the tooth profile and its tip relief can further enhance the performance of the HGT by dramatically improving the Hertz contact property, and maximizing the contact ratio. This high contact ratio leads to ideal load distribution and gradual pickup/release of the vii load (minimization of tooth-to-tooth impact). In the loaded tooth contact analysis, real contact ratio under tooth deformation and load sharing factor were analyzed for demonstration of an effective ‘self-protecting’ feature, which made the HGT suitable for extremely heavy load applications. Finally, effects of manufacturing errors on the contact properties were analyzed for visualization of the error-insensitiveness of the HGT. This thesis successfully proves that the HGT is a promising architecture for use in EM actuators. The design and analysis of these prototype HGTs have been fully documented here.
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Dun-Wei, Su. "Configuration Synthesis of Epicyclic Gear Transmissions". 2005. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2107200514235400.
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Park, Sang-Hyun. "Fundamental development of hypocycloidal gear transmissions". Thesis, 2005. http://hdl.handle.net/2152/2334.
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Su, Dun-Wei, e 蘇敦偉. "Configuration Synthesis of Epicyclic Gear Transmissions". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/51100834745616820200.
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碩士國立臺灣大學
機械工程學研究所
93
A systematic designing procedure to determine the gearing configuration arrangement of epicyclic gear transmissions for given speed ratios is presented. Vertices with symmetric dependency can be chosen from links by topological characteristics. Typical mode sets which are simplified from numerous modes can be established by substituting the symmetric dependency. By identifying the distribution of links, modes can be classified into different types of gain by sketching Kinematic Flow Diagram. In order to find the relations between each mode, the description of gain relations can be established by Rules which can substitute a gain by equations. According to the equations of relations, the sign relations of each mode are determined, and signs are substituted into the modes of typical mode sets. Admissible sign relations are chosen by the constraints of Rules, and inadmissible sign relations are deleted. Admissible configuration arrangements are established by choosing proper gain ranges, and the number of teeth of gear pairs is obtained by calculating teeth ratios.
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Chien-Hong, Lai, e 賴建宏. "Design of Four-Speed Gear Transmissions". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/63053326108766400235.
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碩士國立中山大學
機械工程研究所
86
Gear transmission provides higher performance of power transport and it is widely applied in motorcycle. There are many types of gear transmission. The four-speed gear transmission is most common used for it's proper arrangements of speed ratio and easy to operate. In this thesis, the four-speed gear trans-lation in motorcycle is taken to establish the system's function diagram and related design methodology. These tasks are used to build a transmission with simple structure and smooth variation when changing the speed. At first, this thesis will introduce the motorcycle's transmission and the related list-erature, which are to induce the research goals. A systematic design procedure is provided at latter to lead the design of motorcycle's gear transmission. The following tasks are focusing on the detail design of each component. At last an effective design method for configuring the motorcycle's gear transmission will be developed. The atlas of the four-speed gear transmission's initial structure can be drafted and applied to generate a proper design. The results of this work are of benefit to the development and design of new four-speed gear transmission.
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Cerqueira, Pedro Aires da Cunha. "Mild wear in lubricated gear transmissions". Master's thesis, 2015. https://repositorio-aberto.up.pt/handle/10216/79528.
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Cerqueira, Pedro Aires da Cunha. "Mild wear in lubricated gear transmissions". Dissertação, 2015. https://repositorio-aberto.up.pt/handle/10216/79528.
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Hammami, Maroua. "Efficiency and wear in automotive gear transmissions". Doctoral thesis, 2017. https://repositorio-aberto.up.pt/handle/10216/111956.
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Hammami, Maroua. "Efficiency and wear in automotive gear transmissions". Tese, 2017. https://repositorio-aberto.up.pt/handle/10216/111956.
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HSIAO, HUNG-TA, e 蕭宏達. "Computer-Aided Engineering Analysis of Hypocycloidal Gear Transmissions". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/nf6cgb.
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碩士吳鳳科技大學
光機電暨材料研究所
106
The objective of this research is to push the Electro-Mechanical (EM) actuator technology forward and make it capable of meeting increasingly demanding requirements by improving gear transmission technology which has the most significant effects on actuator performance. The research presents computer-aided design and analysis of the Hypocycloidal Gear Transmission (HGT). Careful design of the curtate cycloid tooth profile can further enhance the performance of the HGT by dramatically improving the Hertz contact property. This high contact ratio leads to ideal load distribution. In the loaded tooth contact analysis, real contact ratio under tooth deformation was analyzed for demonstration of an effective ‘self-protecting’ feature, which made the HGT suitable for extremely heavy load applications. This thesis successfully proves that the HGT is a promising architecture for use in EM actuators. The design and analysis of these prototype HGTs have been fully documented here.
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Lin, Yuh Long, e 林玉龍. "Kinematic Structure of Planetary Gear Trains for Automatic Transmissions". Thesis, 1994. http://ndltd.ncl.edu.tw/handle/78691878565895793617.
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碩士國立中山大學
機械工程研究所
82
Automatic transmission is one of the most important equipments in automobile. The purpose of this work is to propose the a systematic methodology for the synthesis and analysis of the kinematic structure of transmission mechanisms. First, the functions and characteristics of transmission mechanism are clarified. The graph representation and adjacency matrix are used to present the kinematic structure of transmission mechanisms. Then, base on the graph representation, the structural code for mechanism is proposed to identify the isomorphism of transmission mechanism. Then, base on the fundamental circuits, the systematic procedure for the performance analysis of transmission mechanisms is proposed. A computer program is further developed for the automatic performance analysis. Next, a systematic methodology for the synthesis of planetary geared kinematic graph is proposed by using the acyclic graphs. The data base of Structural codes of one-DOF planetary geared kinematic chains up to nine links is listed. Finally, base on the characteristics of transmission mechanisms, the admissible planetary gear trains for transmission mechanism are generated from the data base of structural codes. And an atlas of admissible planetary gear trains up to seven links is listed. The result of this work is of benefit for the kinematic design of transmission mechanisms.
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Tsai, Chin-Chin, e 蔡錦津. "Design of Lepelletier Epicyclic Gear Mechanisms for Automobile Transmissions". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/67699838458992595583.
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碩士國立中山大學
機械與機電工程學系研究所
99
An epicyclic gear mechanism for automobile transmissions is a device which is connected from engine to driving wheels, and the main purpose is to maintain the revolution speed of engine to be in a desired working range while accelerating or decelerating the automobile. The epicyclic gear mechanisms for automobile transmissions in production are mostly Ravigneaux-type, Parallel-connected type and Lepelletier epicyclic mechanisms, and the Lepelletier epicyclic gear mechanisms is a device which is connected with a simple epicyclic gear mechanism besides the input end to increase the total number of speed ratios of an automatic transmission. For the incompletion in the relative design methodology, a systematic methodology of designing Lepelletier epicyclic gear mechanisms for automobile transmission is described. At first, fundamental and gear-shifting operations of the Lepelletier-type automatic transmissions is introduced, and the basic principles of lever analogy is explained, the gear ratio’s analysis for Lepelletier epicyclic gear mechanisms is illustrated to establish the design requirements. Secondly, gearing-sequence is devised base on the lever analogy diagrams, and a systematical procedure to arrange desired clutches and brakes into epicyclic gear mechanisms is provided, then the number of the teeth of all gears can be calculated. At last, the six-speed and eight-speed Lepelletier automatic transmissions are designed base on the above design procedure. The results of this work obtain 19 types of automatic transmission which could reach six-speed.