Tesi sul tema "Machines à tailler les engrenages"
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Senicourt, Jacques-Marie. "Contribution a la reduction du bruit des machines a engrenages". Paris 6, 1987. http://www.theses.fr/1987PA066810.
Testo completoMaatar, Mohamed. "Contribution a l'analyse du comportement dynamique de réducteurs à engrenages simple étage : influence des écarts de forme et des défauts de montage". Lyon, INSA, 1995. http://www.theses.fr/1995ISAL0028.
Testo completoA systematic approach for analyzing the contribution of shape deviations and mounting errors on gear dynamics is proposed. Co1_1tact conditions for bath rigid and deformable solids are used for defining the excitations of the gear unit. A three dimensional lumped parameter non linear dynamic model with a foundation model for tooth contacts is set up. The contact problem and the equations of motion are simultaneously solved using an original iterative method combining a time step integration and a normal contact algorithm. Comparisons with some experimental evidence and several results of the literature illustrate the interest and the versatility of the procedure. The model is sued for characterizing the influence of shape defects and mounting errors such as flank undulations, tooth spacing errors, eccentricities and misalignment on tooth loads and transmission errors. The role of tooth profile modifications is carefully analyzed, it is demonstrated that long reliefs can substantially improve spur and helical gear dynamic behavior on a given load range. Finally, it is shown that inevitable defects and det1ections of the geared unit may strongly reduce the expected gain in dynamic transmission error
Polo, John Anthony. "Application d'engrenages à courbes primitives non circulaires à l'équilibrage de machines". Lille 1, 1992. http://www.theses.fr/1992LIL10146.
Testo completoHennebelle, François. "Détermination des incertitudes de mesures sur machines à mesurer tridimensionnelle : application aux engrenages". Paris, ENSAM, 2007. https://pastel.archives-ouvertes.fr/pastel-00003226.
Testo completoBecause measurands are perfectly defined in standards, Coordinate Measuring Machines (CMM) accreditation is possible for gears provided measurements uncertainties are assessed. In accordance with the Guide to the expression of Uncertainty in Measurement (GUM), our work is mainly based on the Monte Carlo method and linear or circular error separation techniques to differentiate defaults and quantify associated measurements uncertainties. Analysis of the CMM geometry effect on a circular ring or gear measurement shows that it is impossible to characterize completely the CMM geometry with a part supposed to be perfect. However, we set up a concept of “Equivalent defaults” characterizing the CMM geometry for the theoretical definition of the studied part. The probing systems used were assessed in order to compensate the identifiable systematic defaults and quantify associated uncertainties. Based on the example of a cylindrical gear, three different approaches are compared: the analysis of the CMM metrological characteristics, by error separation method and by comparison. This contribution in term of uncertainties measurements has numerous applications; for example the study of penetration rates and wear volumes of explanted total hip prostheses
Assoumane, Amadou. "Diagnostic des engrenages et des roulements par une analyse vibratoire en régime variable". Thesis, Orléans, 2018. http://www.theses.fr/2018ORLE2061.
Testo completoOver the past ten years, several vibration signal-processing methods have been developed for the diagnosisof stationary rotating machines. However, more and more machines under surveillance operate in variable speed condition such as wind turbines, crushers, etc... The methods developed for the monitoring and diagnosis of these machines in steady state are no longer suitable for variable regimes. Some tools proposed for the variable regime case are limited to specific applications or offer a theoretical framework that limits their use in real situations. The purpose of this thesis is precisely to overcome these limitations, and this, by proposing a new approach to analyse the vibration signal acquired in variable regime. The strategy implemented in this thesis is based on a modelling of the vibration signal in the state space and an estimation H∞ of the characteristic quantities of the operating state of the machine. First, we described the vibration signal in the state space through a projection of the envelope of each frequency component of the signal on the orthogonal canonical basis. Then we proposed an estimate of the envelope. This estimation approach is based on a minimax optimization and consists of minimizing the maximum of the estimation error without making any assumptions about the statistical nature of the state model noise. This strategy ledto what we called in this thesis 'BCOH∞ estimator'. The proposed new approach has been applied to synthetic and experimental signals for the diagnosis of gears and bearings condition in variable speed
Breneur, Claire. "Eléments de maintenance préventive de machines tournantes dans le cas de défauts combinés d'engrenages et de roulements". Lyon, INSA, 2002. http://theses.insa-lyon.fr/publication/2002ISAL0096/these.pdf.
Testo completoMachinery used in industrial and transport domains have to be more and more efficient. So, the maintenance of such systems is very important. Interventions must only happen in presence of real damage, and the diagnostic must be reliable and easy to read. This work gave a new elements about the diagnostic of gears power transmissions in case of combined faults of gears and bearings. Gear and bearing faults have been artificially created on an experimental set-up. Transmission error and the bearings accelerations were measured for different operating conditions. Result analysis showed that accelerations envelope signal is an efficient tool for bearings diagnostic, for all operating conditions even in the presence of other defective mechanical components. Moreover, we showed that only accelerations measured in the vicinity of the defective bearing produce a significant pattern of fault presence. According to literature, accelerations analysis produce reliable information about gears health. Yet, we showed that such results are only valid in the case of bearings without any fault. In the presence of simultaneous bearing and gear faults, the transmission error appears as an useful tool giving supplementary information about the gear faults. The obtained results and the established indicators lead to an efficient diagnostic process applied on gear power transmission systems. Moreover, automation of maintenance preventive has been assessed, using neural networks, the used approaches seem to be efficient for the automation procedures, and provides a powerful tool for the optimisation of established indicators
Breneur, Claire Play Daniel. "Eléments de maintenance préventive de machines tournantes dans le cas de défauts combinés d'engrenages et de roulements". Villeurbanne : Doc'INSA, 2004. http://csidoc.insa-lyon.fr/these/2002/breneur/index.html.
Testo completoDiab, Yasser. "Analyse des pertes de puissance dans les transmissions par engrenages à grande vitesse : applications aux réducteurs industriels et aux machines textiles". Lyon, INSA, 2005. http://theses.insa-lyon.fr/publication/2005ISAL0041/these.pdf.
Testo completoPower losses in high-speed gears can be significant and must be taken into consideration at the design stage in order to define the cooling systems, and to avoid mechanism failures due to thermal distortions. It is generally accepted that the total power loss in gears can be decomposed into the contributions of the friction between the teeth, the lubrication process (oil splash or jet), the trapping of air-oil mixture during meshing and finally, tooth windage. The purpose of this work is twofold; on the one hand, to develop various validated models in order to analyse the contribution of each power loss source and, on the other hand, to calculate the efficiency and the expected power losses of four different geared transmissions
Diab, Yasser Velex Philippe Ville Fabrice. "Analyse des pertes de puissance dans les transmissions par engrenages à grande vitesse applications aux réducteurs industriels et aux machines textiles /". Villeurbanne : Doc'INSA, 2005. http://docinsa.insa-lyon.fr/these/pont.php?id=diab.
Testo completoStefak, Roman. "Synthèse de machines moléculaires pour le contrôle de mouvements de rotation et de translation". Toulouse 3, 2013. http://thesesups.ups-tlse.fr/2124/.
Testo completoThis thesis contributes to the field of nanosciences. This manuscript reports the work achieved in order to better understand the rotational and translational motions observed in molecules while those are manipulated as single molecular machines. We first studied the dissymmetrization of the stator (lower anchoring part of the motor) by means of two biphenylene moieties. These fragments were selected to reproduce the behavior of sexiphenyls that can easily move on a surface with the motion analogue to a crawling. Therefore, biphenylenes were designed to allow the molecule to drift in a linear way on the surface using the excitation from the STM tip. In this synthesis, we succeeded to obtain the bipodal bearing two biphenylene moieties. The third indazole subunit could not be added to form the desired dissymmetric stator. Starting from the initial design of the molecular motor previously developed in the group, the first goal of this work was to dissymmetrize the rotor (upper rotating part of the motor) by introducing a nitrogen tag with the purpose of being able to visualize the rotation while this latter is induced by the tip of the STM. The obtained rotor bearing five arms will be used as gears to study the transfer of rotation from one to his neighbours. The last part of this work consists in the development of a new family of rotors based on the double-decker architecture. The upper rotating part is a porphyrin ligand displaying electron donating and withdrawing moieties resulting in a strong dipolar moment with an estimated value of 8 Debye. This unique asset can be used in order to control their rotation by applying an STM tip-induced electric field. This rotor is supported on an europium naphthalocyanine fragment which disables the strong interaction between the rotor and the surface. Thus, an europium heteroleptic double-decker was synthesized and fully characterised. Double-deckers have been studied as monolayers on Cu(111) at 80 K and as single molecule on Au(111) at 5 K using an ultra high vacuum STM. Switching as well as free and synchonised rotational behaviors have been evidenced using different values of bias voltage
Raad, Amani. "Contributions aux statistiques cycliques d'ordre supérieur : applications au diagnostic des défauts d'engrenage". Compiègne, 2003. http://www.theses.fr/2003COMP1471.
Testo completoThe aim of this thesis is vibration and Acoustic Emission (AE) analysis in rotating machinery for monitoring and diagnosis of their gear fauIts. The first section is concerned with the potential of the AE technique by giving a comparison with vibrations. We show the complementarity between the two techniques to give a better diagnosis. Simples descriptors are extracted as kurtosis. The second part is more concerned with a generic modelling of geaI signaIs. This modelling helps to demonstrate the higher order cyclostationarity of gear signàls. We expose after the theory of cyclic bispectrum, third-order statistical too1. We propose at the end simple and concise cyclostationary indicators. Several applications to industrial gear signaIs are illustrated
Ben, Attia Houda. "Détection et localisation de défauts mécaniques d'un entraînement électrique à vitesse variable". Toulouse, INPT, 2003. http://www.theses.fr/2003INPT012H.
Testo completoGomez, Chirinos José Luis. "Angle modeling of a rotating machine. Application to wind turbine surveillance". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI067/document.
Testo completoThis work has been developed within the framework of non-stationary rotating machinery surveillance with emphasis on the detection of roller bearing defects. It focuses on the modeling and analysis of instantaneous angular speed variations. The numerical models developed are based on an ``angular" approach which introduces explicitly the machine's free body rotation degrees of freedom allowing simulations in non stationary operating conditions. A deep groove ball bearing model has been developed coupling tangential and normal forces by taking into account the rolling resistance phenomenon. This coupling allows to explain the origin of angular speed fluctuations in the presence of outer race roller bearing defects, phenomena that has been observed experimentally: a roller bearing defect periodically modifies the friction torque. The description of the gear mesh has been performed by means of a classic approach where the scientific issue has been to verify the compatibility with the angular modeling, cornerstone of this dissertation. Integration of the roller bearing and the gear modeling approaches into a simple mechanical architecture has shown that the presence of bearing defects provoking variations in the rolling element-races normal forces, modifies the gear mesh forces leading to perturbations of the angular speed. A simplified wind turbine model has been used for the test and validation of non stationary surveillance spectral indicators. The robustness of the model has been shown by means of a comparison with measurements performed on a wind turbine. It has allowed to show the importance of the operating conditions (load and speed), on the level of indicators used. This means the model may be used as a tool for phenomenological analyses as well as a device to test surveillance indicators. If needed, the approaches presented may be easily extended into more complex models of bearings, gears, casings and foundations
Le, Marion. "Influence des liserés de carbures induits par la nitruration gazeuse sur les mécanismes de fissuration de fatigue de contacts roulants". Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0102/document.
Testo completoGas nitriding is a thermochemical surface treatment widely used by gear manufacturers to improve the rolling contact fatigue endurance of their components. Indeed, increasing the hardness and introducing compressive residual stresses to the geartooth surfaces inhibit or delay crack initiation and propagation. However, most of the alloyed steel nitrided layers show the presence of intergranular carbide networks. The precipitation of these carbides specifically occurs at parallel grain boundaries during the treatment and, being a carbon-rich phase, they are associated to tough and fragile heterogeneities. Besides, standards for gear material quality recommend a broad range of steel grain sizes which lead to various possible microstructures on gear components after nitriding. Indeed, the intergranular carbide network morphology depends on the steel grain size. Since there is no evidence regarding the real effect of the carbides on rolling contact fatigue, this work presents experimental investigations carried out on a twin-disc machine. The tests consist in reproducing surface-initiated pitting on specimens whose nitrided layers, obtained by a unique thermochemical surface treatment, display similar mechanical properties (hardness and compressive residual stresses) but different microstructures (grain sizes and carbide network morphologies). The first analysis resulted in suggesting the micro-crack nucleation mechanisms. In this study, the test conditions were chosen to induce these micro-cracks near the disc surfaces. For a given contact stress field, nucleation sites depend on the steel grain size and can take place at intergranular carbides. Investigations of crack networks led on cross sections and 3D observations by means of high energy X-ray computed tomography, coupled with compressive residual stress evolution analysis, help the authors proposing the rolling contact fatigue crack propagation scenarios in nitrided layers. When contact shear stresses locally exceed the material micro-yield shear stress limit, micro-deformations arise and add compressive residual stresses to the treated layers. To accommodate these volume variations the compressive residual stresses, initially induced by nitriding, release at depths where contact stresses are lower. The pre-existing residual stresses being less compressive, micro-cracks near the surface can propagate through the carbides that act as preferential crack growth sites. When the nitrided layers display high carbide density, the intergranular precipitates drag the cracks toward the core, whereas rolling contact fatigue failures are limited to the near surface when the distance between the precipitates is too important. Finally, the length and the continuity of the carbides, linked to the steel grain size, locally increase the crack propagation speed. This gives rise to a lower endurance to surface-initiated pitting in coarse microstructures
Gousseau, William. "Pronostic de dégradation d'endommagements de roulements sur application aéronautique par analyse vibratoire". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI063.
Testo completoAs part of preventive maintenance of its engines, Safran Aircraft Engines wishes to complete its diagnostic operations with a reliable prognosis of the residual life of the bearings. Following an attack, there is currently a great deal of uncertainty about the remaining life before bearing failure from the threshold of vibrational observability of the damage. Current algorithms diagnose an approximate stage of degradation and generate alarm messages of different levels, each level corresponding to a different stage of degradation, combining confidence and severity of diagnosis. An important aspect of the prognosis is the taking into account of the contextual parameters influencing the rate of degradation. The objectives of this thesis are to have methods and tools to quantify a running time remaining before bearing failure with regard to: - the severity of the damage detected, - the environmental conditions of operation, - the depth The industrial constraints associated with these objectives are as follows: 1) The prognosis should be based, at least, on high-frequency vibratory measurements of a few kHz (accelerometers), contextual data (the rotational speeds of the different rotors, for example, or the amplitudes of the levels piloted on them), rotation regimes, revealing a loading of the bearings) 2). Constituing a database of tests resulting from a plan of experiments: these tests will have to take into account the constraints related to the control of the parameters considered to be significantly influential 3) This database must take into account the representativity of the vibratory environment of an aircraft engine. 4) Propose a tool or method of prognosis taking into account the nature of the bearing to consider
Hennebelle, François. "Détermination des incertitudes de mesures sur machines à mesurer tridimensionnelles : application aux engrenages". Phd thesis, 2007. http://pastel.archives-ouvertes.fr/pastel-00003226.
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