Analysis of the behavior of cylindrical roller bearings for special applications

U radu se razmatra problematika ponašanja cilindrično valjkastih ležaja za uležištenje glavnih vretena mašina alatki i osovinskog sklopa vučenih vozila na železnici. Za definisano konstrukciono rešenje uležištenja sklopa glavnog vretena izvršena su eksperimentalna ispitivanja toplotnog ponašanja čime su provereni i potvrđeni rezultati računarskog modelovanja (2D i 3D). U prvom poglavlju polazi se od značaja cilindrično valjkastih ležaja za uležištenje sklopova glavnih vretena i osovinskog sklopa vučenih vozila na železnici. Konstrukcioni parametri valjkastih ležaja opisani su i objašnjeni u drugom poglavlju. U trećem poglavlju izvršen je pregled stanja u oblasti u dva pravca: ponašanje sklopova glavnih vretena i osovinskih sklopova na železnici. Literaturni izvori su grupisani na one koji se bave problematikom statičkog, toplotnog ponašanja i oštećenjima ležaja. Matematički modeli za analizu statičkog, toplotnog ponašanja, veka ležaja kao i programsko rešenje za određivanje veka ležaja dati su u okviru četvrtog poglavlja. Prikazan je opšti algoritam ponašanja cilindrično valjkastih ležaja, kao i agoritmi statičkog, toplotnog ponašanja i veka ležaja. Dati su modeli za određivanje nelinearne krutosti u radijalnom pravcu za valjkaste ležaje. Na osnovu Ševalove teorije rasporeda opterećenja razvijen je nelinearni model generisanja toplote u ležaju. U petom poglavlju izvršeno je računarsko modelovanje statičkog i toplotnog ponašanja sklopa glavnog vretena uležištenog cilindrično valjkastim dvoredim ležajem. Analizirani su modeli dvodimenzionog i trodimenzionog sklopa glavnog vretena i određene su vrednosti temperature na vrhu vretena. Veličina konačnih elemenata imala je zanemarljiv uticaj na rezultate toplotnog ponašanja. U okviru ovog poglavlja ukazuje se na činjenicu da je predikcija toplotnog ponašanja mašine alatke uslovljena ponašanjem odgovarajućih sklopova, a posebno sklopa glavnog vretena. Definisanje svih izvora generisanja toplote u osovinskom sklopu kao i njihova analiza izvršeni su u okviru poglavlja šest. Potvrđena je hipoteza da na temperaturu ležaja zanemarljiv uticaj imaju generana toplota usled kotrljanja točka po šini i generisana toplota usled kočenja u odnosu na temperaturu koja se generiše u ležaju usled obrtanja i opterećenja. Sedmo poglavlje odnosi se na eksperimentalna istraživanja toplotnog ponašanja konstrukcionog rešenja sklopa glavnog vretena uležištenog cilindrično valjkastim dvoredim ležajem. Za eksperimentalna istraživanja korišćeni su savremeni merni instrumnti za merenje temperature kontaktnim i bezkontaktnim metodama. Uticaj generisane toplote usled kotrljanja točka po šini i usled kočenja eksperimentalno je ispitivan termovizijskom kamerom i prikazan u poglavlju osam. Na kraju je u poglavlju devet izvršena analiza eksperimentalnih i računarskih rezultata ponašanja valjkastih ležaja za glavna vretena, kao i analiza rezultata računarskog modelovanja ležaja za osovinske sklopove vučenih vozila na železnici. Deseto poglavlje sadrži zaključke, na osnovu rezultata pojedinih poglavlja i izvedenih istraživanja. Nakon toga dati su pravci budućih istraživanja. Jedanaesto poglavlje sadrži pregled korišćene literature, koju čini 135 literaturnih naslova od kojih je određeni broj citiran u radu.The paper deals with the problem of behavior of cylindrical roller bearings for loosening the main spindles of machine tools and the axle assembly of towed vehicles on the rail. For the defined constructional arrangement of the mounting of the main spindle assembly experimental tests of thermal behavior were performed which confirmed and confirmed the results of computer modeling (2D and 3D). The first chapter starts from the significance of cylindrical roller bearings for the installation of the main spindle assemblies and the axle assembly of towed vehicles on the rail. The construction parameters of roller bearings (external and internal bearing geometry and bearing lubrication) are described and explained in the second chapter. The third chapter was conducted review of the state in the field in two directions: the behavior of the main spindle assemblies and axle assemblies on the rail. The papers are grouped into those dealing with problems of static, thermal behavior and bearing damage. Mathematical models for the analysis of static, thermal behavior, bearings life as well as the software solution for determining the bearing life are given in the fourth chapter. A general algorithm behavioral for cylindrical cylindrical bearings, as well as and algorithm static, thermal behavior and bearing life. Models are given for determining nonlinear stiffness in the radial direction for roller bearings. Based on Sjoväll's theory of load distribution, a nonlinear model of heat generation in a bearing is developed. In the fifth chapter, a computer modeling of the static and thermal behavior of the main spindle assembly is carried out with a double row cylindrical roller bearing. The two-dimensional and three-dimensional models of the main spindle were analyzed and the temperature values at the top of the spindle were determined. The size of the finite elements had a negligible impact on the results of thermal behavior. Within this chapter, it is pointed out that the prediction of the thermal behavior of the machine tool is conditioned by the behavior of the corresponding assemblies, and in particular the main spindle assembly. The definition of all sources of heat generation in the axle as well as their analysis were carried out under Chapter six. The hypothesis was confirmed that the negligible impact on the bearing temperature is due to generating heat due to rolling the wheel along the rail and generated heat due to braking relative to the temperature generated in the bearing due to rotation and load. Chapter Seven refers to experimental investigations of the thermal behavior of the construction of the main spindle assembly with cylindrically cylindrical two-row bearing. For experimental measurements were used modern measurement instruments for temperature measurement by contact and without contact methods. The influence of generated heat due to rolling of the wheel along the rail and due to braking was experimentally tested by a thermal camera and shown in chapter eight. In the end, in chapter nine, an analysis of the experimental and computer results of the behavior of roller bearings for the main spindles was performed, as well as an analysis of the results of computer modeling of bearings for axle assemblies of towed vehicles on the rail. Chapter ten contains conclusions, based on the results of individual chapters and research carried out. After that, the directions of future research are given. Chapter eleven contains an overview of the used literature, made up of 135 literary titles, of which a certain number is cited in the paper