Baigiamajame magistro darbe nagrinėjamos statinės ir dinaminės jėgos veikiančios tiesiaeigiame žingsniniame variklyje (TŽV). Apžvelgiami žingsninių variklių tipai, jų savybės ir charakteristikos. Analizuojamos variklio postūmio ir traukos jėgos bei matematinio modelio sudarymas. Tiriamojoje dalyje tiesiaeigiuose žingsniniuose varikliuose veikiančios jėgos tiriamos sudarant matematinius modelius, visi skaičiavimai atlikti naudojant programinį paketą MATHCAD. Ekperimento metu gautų rezultatų apdorojimui naudojamas programinis paketas DynaMax. Gautos statinės jėgos dedamųjų Fx, veikiančios išilgai judėjimo krypties, ir Fy, veikiančios vertikaliąja ašimi, priklausomybės nuo polių postūmio danties atžvilgiu, keičiant įvairius parametus (poliaus ir danties pločių santykį, magnetinę įtampą, oro tarpą). Taip pat atlikti tyrimai, parodantys kaip kinta dinaminė jėga, esant skirtingoms apvijos maitinimo įtampoms. Teoriniai skaičiavimai palyginti su eksperimentiniais tyrimo rezultatais. Išnagrinėjus teorinius ir praktinius matavimus pateikiamos baigiamojo darbo išvados ir pasiūlymai. Darbą sudaro 6 dalys: įvadas, teorinė dalis, tiriamoji dalis, išvados ir pasiūlymai, literatūra, priedai. Darbo apimtis – 70 psl. teksto be priedų, 45 iliustr., 14 lent., 14 bibliografiniai šaltiniai, 11 internetinių prieigų. Atskirai pridedami darbo priedai. / At the final Master's work dealt with the static and dynamic forces acting linear stepper motor (LSM). Overview of types of stepping motors, their properties and characteristics. Examines the push and pull the engine and the power of the mathematical model. The exploratory part of rectilineal stepping motors operating in the force under investigation for the mathematical models, all calculations performed using the software package MathCAD. Experimentation of the results of treatment using the software package DynaMax. The resulting static force added Fx, acting along the direction of movement, and the Fy in the vertical axis of dependence on the poles pull the tooth, the modification of various parameters (polarity, and the tooth width ratio, magnetic tension, the air space). Studies also showing changes in dynamic forces at different supply voltage windings. Theoretical calculations compared with experimental test results. The examination of the theoretical and practical measurements are presented on the final conclusions and proposals. Structure: introduction, theoretical part, searching part, conclusions and suggestions, references, appendix. Thesis consist of: 70 p. text without extras, 45 pictures, 14 tables, 14 bibliographical entries and 11 internet entries. Appendixes included.

Le mémoire traite de la machine à réluctance variable en proposant d'une manière simultanée et du point de vue conception des solutions à ses deux inconvénients majeurs à savoir les ondulations de couple et les efforts radiaux. Les premières se propagent le long de la chaine de transmission diminuant ainsi le confort des usagers et les deuxièmes sont à l’origine d’une nuisance sonore. Dans une première partie et en s’intéressant à une structure axiale caractérisée par une faible force radiale, un bilan sur cette structure est donc établi. En effet, une configuration à deux stators et un rotor est la plus adéquate pour éventuellement remplacer la machine radiale de référence. Cette structure axiale est comparée à cette machine de référence après avoir établi des règles de passage d’une structure à une autre. Un premier passage est effectué en gardant le même encombrement et un deuxième passage en dimensionnant la machine axiale pour satisfaire le même cahier des charges que la machine radiale. Dans une deuxième partie, le travail s’oriente vers la modification de la structure radiale de la machine de référence et son optimisation. Plusieurs modifications sont proposées dont une structure avec une cale magnétique qui est la plus performante. Des optimisations géométriques à l’aide de l’algorithme génétique sur un point de fonctionnement sont ensuite effectuées pour remédier aux deux problèmes. A la fin, un récapitulatif de plusieurs structures optimisées est proposé pour servir de référence. Le choix de la machine la plus adéquate pourra donc être effectué en faisant un compromis entre la maximisation du couple, la réduction de ses ondulations et la réduction des efforts radiaux. / This report deals with switched reluctance motor by offering design solutions to the drawbacks of torque ripples and radial forces in the same time. Torque ripples reduce the user comfort and radial forces are the origin of noise. In the first part, an axial structure characterized by low radial force is analysed. Indeed, an axial configuration with two stators and one rotor is the most appropriate to replace the reference radial machine. Ones the rules of passage from one structure to another are established, the axial structure is then compared to the reference one. A first passage is made by keeping the same volume and a second one by sizing the axial machine with the same specifications as the radial one. In the second part, the work concerns the modification of radial structure of the reference machine and its optimization. Several modifications are proposed including a structure with a magnetic wedge which is the most efficient. Geometric optimization using genetic algorithm are then performed on operating points to remedy the both problems. In the end, several optimized structures are proposed. The choice of the most suitable machine can be done by making a compromise between the torque maximization, reducing its ripples and reducing radial forces.

The aim of this thesis is to calculate the stiffness and damping coefficients for radial hydrodynamic bearings. Cylindrical and lemon hydrodynamic bearings are considered. The solution to this problem mainly depends on the hydrodynamic pressure in the bearing. The numerical solution of the Reynolds equation is used to calculate the pressure. The effect of variable viscosity and density of the lubricant due to temperature changes is considered. The static equilibrium position of the journal centre is also solved. The stiffness and damping coefficients are determined using small amplitude journal motions about the equilibrium position. Three methods for determining these coefficients are presented. The outcome of this thesis is an algorithm for the calculation of stiffness and damping coefficients for cylindrical and lemon bearings. Results for lemon bearings are presented and comparison with the commercial software DynRot BR is made. The benefit of this thesis is the creation of an algorithm for the calculation of journal centre equilibrium position, a new way of incorporating the temperature changes in the viscosity and the density of the lubricant, and the modification of a method for calculating stiffness and damping coefficients based on experimental analogy.