Дисертації: "High-speed bearings"

1

Frew, David Anthony. "The design, development and vibration analysis of a high-speed aerostatic bearing." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/362.

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2

Karthikeyan, Bindu Kumar. "Tribo-dynamics of high speed precision spindle bearings." Thesis, Loughborough University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547399.

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3

Pu, Guang. "Hybrid air bearings for high speed turbo machinery." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7789/.

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This PhD project is set out to develop a type of hybrid journal air bearings with reduced reliance on the supply of compressed air for mobile turbomachinery applications. The research work covers hydrostatic and hybrid journal air bearings with non-compliant clearance boundaries. The approach adopted combined numerical analysis based on CFD and experimental verification of the designs. The research can be divided into three sections. In the first section, numerical approaches to model hydrostatic and hybrid journal air bearings with a fixed clearance boundary were developed based on finite difference method (FDM) and finite volume method (FVM) respectively. In the second and third section, theoretical and experimental studies were performed on hydrostatic and hybrid journal air bearings. Performance of the bearings was investigated in non-rotational and rotational conditions. The analysis on stability and natural frequencies of rotor bearing system was performed using the linear bearing model. The unbalance responses of the rotor in the test rig were predicted using non-linear transient analysis and measured experimentally from 50k rpm to 120k rpm in rotor speed. Through the theoretical and experimental investigations of the hybrid journal air bearings, the objectives of the project have been implemented and the aims have been met.

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4

Wasson, Kevin L. (Kevin Lee). "Hydrostatic radial bearings for high speed precision machine tool applications." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/12287.

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5

Wong, Chee Wei 1975. "Design, fabrication, experimentation and analysis of high-speed microscale gas bearings." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8876.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.
Includes bibliographical references (p. [183]-190).
Microengine Program. The all-silicon device consist of a free-rotating microturbine, with 4.2 mm rotor diameter, enclosed within a five wafer fusion-bonded stack. Of note are the low aspect ratio journal bearing and large journal bearing clearances, primarily limited by microfabrication, from which stable bearing operation must first be demonstrated as viable. Theoretical modeling of the gas-lubricated hydrostatic journal bearing presents design charts, a comparative study of existing predictions and investigation into rotational effects to consider the bearing stiffness during operation. Continued experimental refinements and exploration with our microfabricated rotor achieved rotational speeds up to 1.4 million rpm and peripheral speeds in excess of 300 m/s. Extensive experimental data is presented with analysis, focusing on whirl motion and its harmonic resonances as candidates for instability. Causes of ultimate failure is suggested with recommendations for further improvements. Moreover, in an effort to accomplish self-sustained microbearings, the axial thrust bearing is redesigned for a self-acting spiral groove bearing. The chosen constraint is to incorporate the hydrodynamic thrust bearing with minimal changes to the current device, whilst providing the required load and stiffness. Stability analysis and rarefaction considerations on the optimized design suggests an operating range for the bearing, leading to a hybrid design for ample stiffness during initial operation. The design is then developed into a microfabrication process flow and implemented successfully into the MicroBearing test devices. Experiments on a hybrid bearing were performed to gage the spiral grooves characteristics. A purely hydrodynamic aft thrust bearing device is then tested for operation through low speeds, although the effects of the spiral grooves could not be accurately determined. Finally, transition to a hydrodynamic operating mode for a hybrid bearing is demonstrated.
by Chee Wei Wong.
S.M.

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6

Orr, Doyle Jay 1969. "Macro-scale investigation of high speed gas bearings for MEMS devices." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/9268.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2000.
Includes bibliographical references (p. 309-315).
A macro-scale experimental test facility for investigating high-speed gas bearings for MEMS devices such as the MIT Micro-Engine is presented along with results from subsequent experiments. It is shown that the bearings required by such MEMS devices fall outside the usual range of design parameters for conventional gas lubrication systems. Due to the unorthodox design of the bearings, a new "hybrid" mode of operation is introduced along with the traditional hydrodynamic regime. The new hybrid mode is exploited to implement a novel in-situ rotor balancing scheme which enables hydrodynamic operation. Analysis for both modes of operation is presented along with experimental results. A high-order, efficient scheme for computing both the steady and unsteady hydrodynamic properties of the fully coupled, rotor/gas film dynamical system is presented along with comprehensive calculations for this class of plain, cylindrical, gas journal bearing. The scheme is then used to perform a generalized eigenvalue analysis on the compressible, unsteady system which reveals a new type a hydrodynamic instability. From a fundamental understanding of the bearing physics, strategies for operating MEMS devices with this class of bearing are deduced and minimum requirements for the accompanying measurement systems are established. Ancillary issues such as axial equilibrium of the rotor are discussed in detail.
by Doyle Jay Orr, Jr.
Ph.D.

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7

Martin, M. J. "Elastohydrodynamic films and scuffing behaviour in high speed angular contact ball bearings." Thesis, Cardiff University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.543267.

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8

Gao, Wenjun. "Modelling of windage and churning losses in high speed rolling element bearings." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI048/document.

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Dans un système de machines rotatives comme un moteur à turbine, les paliers d'éléments roulants à grande vitesse jouent un rôle important dans le support de l'arbre ou du rotor rotatif, et ont besoin d'une lubrification pour assurer leur fonction. Sauf qu'une petite quantité d'huile est nécessaire pour former le film lubrifiant élastohydrodynamique dans la zone de contact, la plus grande partie du lubrifiant reste en suspension dans l'air, formant un mélange huile/air. Ce phénomène entraîne des pertes hydrauliques parasitaires excessives lorsque les éléments roulants se translatent et tournent dans l'environnement fluide, ce qui peut constituer une partie relativement importante de la perte de puissance totale du roulement, appelée traînée d'enroulement et pertes de barattage. Pour une vitesse de rotation jusqu'à 3× 106 Ndm, la contribution de la traînée/dérive au total peut atteindre 50%. Cependant, jusqu'à présent, il existe peu d'approches utilisées directement pour l'estimation des pertes par traînage, qui ne pouvait fournir qu'une approximation plutôt grossière. Dans cette thèse, la méthode CFD est utilisée pour analyser d'abord l'écoulement autour d'un cylindre circulaire de longueur finie avec deux extrémités libres dans un espace ouvert. Ensuite, le modèle est remplacé par plusieurs cylindres circulaires en ligne pris en sandwich par deux parois plates, ce qui représente une approche simplifiée. Le fluide est ici considéré comme incompressible, représentant un fluide monophasé équivalent pour l'écoulement diphasique huile/air à l'intérieur de la cavité de palier avec des propriétés de fluide spécifiées. Les résultats indiquent que l'écoulement autour de l'élément de rouleau de longueur finie est perturbé par ses deux extrémités libres, les anneaux environnants, la cage et d'autres éléments roulants. Il est proposé une relation entre le coefficient de traînée et le nombre de Reynolds approprié pour un cylindre circulaire dans les roulements à rouleaux (1
In a rotating machinery system like turbine engine, high speed rolling element bearings play an important role in supporting the rotating shaft or rotor, and need lubrication to insure their function. Except a small quantity of oil is needed to form the elastohydrodynamic lubricant film in the contact zone, most of lubricant remains in suspension in air, forming an oil/air mixture. This phenomenon leads to excessive parasitic hydraulic losses when rolling elements translate and rotate into the fluid environment, which may constitute a relatively large portion of the bearing's total power loss, named windage drag and churning losses. For high speed applications, i.e. for rotational speed up to 3× 10^6 Ndm, the contribution of drag/windage loss to the total one may reach up to 50%. However, so far there are few approaches used directly for drag and churning losses estimation, which could only provide a rather gross approximation. In this thesis, the Computational Fluid Dynamics (CFD) method is employed to analyze first the flow around one finite-length circular cylinder with two free ends in an open space. Then the model is changed to several in-line circular cylinders sandwiched by two flat walls, which represents a simplified approach. The fluid here is regarded as incompressible, representing an equivalent one-phase fluid for the oil/air two-phase flow inside the bearing cavity with specified fluid properties. The results indicate that the flow around the finite length roller element is perturbed by its two free ends, the surrounding rings, the cage and other rolling elements. A relationship between the drag coefficient and the Reynolds number suitable for circular cylinder in roller bearings (1

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9

Kim, Tae Hyun. "Fatigue of surface engineered steel in rolling-sliding contact." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325019.

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10

Rodriguez, Colmenares Luis Emigdio. "Experimental frequency-dependent rotordynamic coefficients for a load-on-pad, high-speed, flexible-pivot tilting-pad bearing." Texas A&M University, 2003. http://hdl.handle.net/1969.1/138.

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This thesis provides experimental frequency dependent stiffness and damping coefficient results for a high-speed, lightly loaded, flexible-pivot tilting-pad bearing, with a load-on-pad configuration. Test conditions include four shaft speeds (6000, 9000, 13000 and 16000 rpm), and bearing unit loads from 172 kPa to 690 kPa. The results show that the bearing stiffness is a quadratic function of the frequency of vibration; hence their frequency dependency can be modeled by added-mass terms. The additional degrees of freedom introduced by the pads and the influence of the inertial forces generated in the fluid film account for this frequency dependency. The conventional frequency-dependent stiffness and damping model for tilting-pad bearings is extended with an added-mass matrix to account for the frequency dependency. This approach allows the description of the bearing dynamic characteristics with frequency-independent stiffness, damping and added-mass matrices. Experimental results are compared with predictions from the Reynolds equation and from a bulk-flow Navier-Stokes model. Both models produce good predictions of the stiffness and damping coefficients. However, results show that the bulk-flow model is more adequate for predicting the direct added-mass terms because it accounts for the fluid inertial forces. A bulk-flow solution of the Navier-Stokes equations that includes the effects of fluid inertia should be used to calculate the rotordynamic coefficients of a flexible-pivot tilting-bearing. Static performance measurement results are also detailed. Results include pad metal temperatures, eccentricity-ratios and attitude-angle as a function of bearing load, and estimated power losses.

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11

Kamf, Tobias. "High speed flywheel design : Using advanced composite materials." Thesis, Uppsala universitet, Elektricitetslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-181256.

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This thesis is a part of a larger project that focuses on the development of a highspeed, high energy flywheel using both high-tech composites and levitating magneticbearings alongside a custom made, permanent magnetized generator built into theflywheel itself. The goal of the project is then to integrate this flywheel into anelectrical vehicle.The main focus of this thesis is the composite material. The composite is to be usedas a shell around the flywheel rotor. This composite shell fills two purposes. The firstis to act as the main energy carrying material, storing above 75% of the total energy inthe flywheel. The second purpose it to strengthen the machine, holding it together.This so that higher speeds than normally possible can be achieved, with the goal beingset to 30 000rpm.In order to be able to design the composite shell correctly a method of calculating theload stresses had to be developed. This was done by the creation of a Matlabprogram, named Spin2Win, capable of calculating the stresses inside a compositemetal hybrid flywheel. Using said Matlab code, combined with modelling andsimulations from SolidWorks, a fully-fledged flywheel was designed complete withdrawings and material specifications.The composite analysis surprisingly shows that the best combination of compositematerials is a mixture of both high strength carbon fibres alongside softer glass fibrescoupled with the weight of the central core. This allowed for control of the radialstresses which was shown to otherwise be the limiting factor when designing rotatingcomposite materials.One of the most interesting, and perhaps even unique, parts of the design is that theelectrical machine has been integrated into the flywheel’s composite shell. Having thetwo entities working together in order to control the radial stresses in thecomposite, by utilizing the weight of the permanent magnets.

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12

KEHLENBACH, JOSUA. "Fault diagnosis of axlebox roller bearings of high speed rail vehicles based on empirical mode decomposition and machine learning." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299774.

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Axlebox bearings are one of the most critical components of a rail vehicle with regard to safety. An axlebox bearing that breaks during operation can be dangerous for the passengers and expensive for the operator. In-service failure of axlebox bearings has been the cause of many catastrophic accidents. Thus, it is of utmost importance to predict bearing failures as early as possible. This will increase reliability and safety of the vehicle as well as reduce the vehicle maintenance cost. Monitoring of roller bearings is an active research eld, and many methods have been proposed by other researchers. Many of these methods employ complex algorithms to make the most use of the given measurements. The algorithms often lack interpretability and have high computational costs, making them dicult to employ in an on-board system. This thesis proposes an interpretable and transparent algorithm that predicts bearing damages with high accuracy. Meanwhile, it tries to retain interpretability as much as possible. The algorithm is based on Empirical Mode Decomposition (EMD) and Singular Value Decomposition (SVD). These two techniques extract essential and meaningful information from the axlebox accelerations. The algorithm is benchmarked on two benchmark datasets, and the results are compared to the respective literature. Then the algorithm is employed on the railway axlebox acceleration measurements that were taken on an axlebox test bench available at SWJTU. The proposed algorithm can be extended to incorporate additional measurements of dierent types, e.g. sound or temperature measurements. The incorporation of other types of measurements will improve the performance of the algorithm even further.
Axelbox lager är en av de viktigaste komponenterna i ett järnvägsfordon när det berör säkerheten. Ett axelbox lager som havererar under drift kan vara farligt for passagerarna och även dyrt för operatören. Driftfel av lagren har varit orsaken till många katastrofala olyckor. Därför är det av yttersta vikt att förutsäga lagerfel så tidigt som möjligt. Detta ökar fordonets tillförlitlighet och säkerhet samt minskar underhållskostnaderna. Mycket forskning har utförts inom övervakning av rullager. Många metoder använder komplexa algoritmer för att maximalt utnyttja matningarna. Algoritmerna saknar ofta tolkbarhet och har höga beräkningskostnader, vilket gör dem svåra att använda i ett integrerat system. Denna avhandling kombinerar era metoder för databehandling och maskininlärning till en algoritm som kan förutsäga lagerskador med hög precision, samtidigt som tolkningsförmågan bibehalls. Bland andra välkända metoder sa använder algoritmen Empirical Mode Decomposition (EMD) och Singular Value Decomposition (SVD) för att extrahera väsentlig information for vibrationsmätningarna. Algoritmen testas sedan med tre olika vibrationsdatamängder, varav en mättes specikt med tanke på simulering av axelbox lager. Ett annat mål med algoritmen är att göra den tillämpad för ytterligare mätningar. Det bör vara möjligt att inkludera mätningar av olika slag, dvs ljud- eller temperaturmätningar, och därigenom förbättra resultaten. Detta skulle minska implementeringskostnaden avsevärt eftersom befintliga sensorer används för detta ändamål. I händelsen av att de föreslagna metoderna inte fungerar med nya mätningar är det även möjligt att integrera ytterligare funktioner i algoritmen.

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13

Rowan, D. "Design and development of a high-speed test facility and the measurement of the fluid film characteristics of journal bearings." Thesis, Cranfield University, 1998. http://dspace.lib.cranfield.ac.uk/handle/1826/11357.

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In the theoretical analysis of high speed rotor bearing systems, it is common to use four displacement and four velocity based coefficients, which characterise the behaviour of the lubricating fluid film. Although a great deal of work has been published establishing theoretical models of all types of hydrodynamic journal bearings, the large amount of experimental work has centred on relatively low speed conditions. This work presents a contribution to the experimental study of the static and dynamic characteristics of oil films in journal bearings used in high-speed rotating machinery. The main objectives of the work are: • To devise new experimental techniques for the measurement of dynamic coefficients suitable for use at high rotational speeds • To design, manufacture, assemble and commission a test facility to measure the static and dynamic characteristics of journal bearings at speeds up to 30000 rpm • To determine the static and dynamic characteristics of a 5 Pad Tilting Pad Journal Bearing Unit of 80 mm diameter at speeds up to 25 000 rpm using the said test facility. New techniques are particularly necessary for the measurement of velocity coefficients because these invoke the necessity of imposing a velocity on to the bearing housing and previous techniques have utilised synchronous motion of the bearing. Consequently a new experimental procedure for measuring the four velocity or damping coefficients of an oil film journal bearing from imposed dynamic "orbits" has been devised called the "double pulse" technique. All four velocity coefficients are derived from one imposed journal centre dynamic orbit and, therefore may be regarded as being obtained at the same time. The method requires the production of a "cross- over" point similar to that of a "figure of eight" shaped orbit and utilises the "cross-over" point therein. Coefficients are initially evaluated in a co-ordinate system, which is chosen to align with the designated parts of the measured orbit. Each coefficient is then evaluated from single values of instantaneous imposed force and resulting journal centre velocity. Coefficients are them converted into any other desired axes system. The result is a simpler experimental procedure, with reduced uncertainty compared to hitherto existing methods. The use of non-sinusoidal excitation of the oil film was explored, in the form of applying a step-pulse train load pattern to produce a cross-over pattern in the journal displacement ·orbit'. Experimental tests were completed on a tilting pad bearing at speeds up to 15 000 rpm inclusive. At speeds above this, the bearing exhibited a vibrational response, which precluded the accurate measurement of journal centre displacement.

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14

Sabirin, Chip Rinaldi [Verfasser]. "Digital Control for Active Magnetic Bearings in High-Speed Permanent-Magnet Synchronous Machine with 40000 rpm and 40 kW / Chip Rinaldi Sabirin." Aachen : Shaker, 2014. http://d-nb.info/106619789X/34.

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15

Wei, Sicong. "A 3D Sliding Bearing Finite Element Based on The Bouc-Wen Hysteretic Model : Mathematical modelling and numerical implementation." Thesis, KTH, Bro- och stålbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-289480.

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Bridge bearing is an essential component with the function of connecting the superstructure and substructure of the bridge, transmitting load and providing movability to the superstructure. Under dynamic conditions, the internal friction of bridge bearing dissipates the vibration energy and therefore reduces the dynamic response of the bridge. Meanwhile, bearing friction is considered to have possible contribution to some nonlinear dynamic behaviour of the bridge structure, which requires further investigation.However, bearing friction, in most cases, are ignored or considered roughly and implicitly as part of structural damping in current bridge designing codes and methods. Most previous research was also focusing on bearing friction’s effect under high-amplitude vibration conditions, such as earthquake or heavy wind load. Bearing friction’s effect under common low-amplitude vibration in SLS such as train-induced vibration and vehicle-induced vibration is less attended. Although the effect of such low-amplitude vibration is less significant to structural safety, it plays an essential role to the bridge’s traffic safety and comfort. Meanwhile, the cumulative effect of such vibration can significantly influence the life and durability of bridge bearings due to its high occurring frequency. Hence, a clearer understanding of bearing dynamic behaviour is required to improve the understanding of bridge and bearing dynamics.In this thesis, an advanced numerical tool is developed for dynamic analysis of bearing friction. A 3D pot bearing finite element that can be implemented in commercial FE software ABAQUS, is programmed based on the mathematical friction models developed in previous research and the Bouc-Wen hysteretic model. Numerical results that accord with the results of relevant friction tests are produced by the calibrated and validated bearing finite element, giving proof that the element is capable to reflect the dynamic friction response of bridge pot bearing in reality.The 3D shell numerical model of Banafjäl bridge located on the Bothnia Line in Norrland, Sweden, is built as a study case of bridge dynamic analysis in this thesis, with implementation of the newly developed bearing element. The feasibility of implementing the bearing element in bridge dynamic analysis is proven by the numerical results. The nonlinear influence of bearing friction on the dynamic response of bridge structure, especially the influence on structural damping properties, is discussed preliminarily. The analysis results show that with the consideration of bearing friction, the damping presents a clear amplitude-dependency, which accords the phenomenon reported in previous research.

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16

Niel, Dimitri. "Etude du comportement thermomécanique de paliers à roulements pour une application hautes vitesses." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI007/document.

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Avec l’apparition de moteur électrique dans le secteur automobile, les réducteurs mécaniques fonctionnent à des vitesses de rotation de plus en plus élevées. Pour ce type de réducteur, les pertes de puissance au niveau des paliers à roulements peuvent être prédominantes pour des vitesses de rotation élevées. Ces pertes sont fortement dépendantes du comportement thermique du palier à roulement. D’où l’intérêt de développer des outils numériques permettant d’estimer les puissances générées au sein d’un palier à roulement. Cette estimation permettra en phase de pré-étude de développer un dispositif de refroidissement adapté afin d’éviter tout risque de dégradation du palier à roulement. Cette thèse présente une nouvelle approche permettant d’étudier le comportement thermomécanique de palier à roulement. Cette approche intermédiaire requiert un minimum de paramètres d’entrée (géométrie externe du palier à roulement et condition de fonctionnement). Elle utilise la méthode dite « des réseaux thermiques » pour obtenir une interconnexion entre les pertes de puissance et le comportement thermique du palier à roulement. Enfin cette approche permet de calculer la puissance dissipée au sein d’un roulement et les températures des bagues et du lubrifiant principalement pour une application hautes vitesses. Cette approche est développée pour des roulements à billes à gorge profonde et contact oblique. Des valeurs expérimentales sont nécessaires pour valider cette nouvelle approche. C’est pourquoi, un nouveau banc d’essai modulaire dédié à l’étude du comportement thermomécanique de palier à roulement a été développé. Sur ce nouveau moyen d’essai, une grande variété de paliers à roulements peut être testée pour différentes conditions de fonctionnement. Pour les premiers essais, un roulement à billes à gorge profonde lubrifié par injection est testé pour un fonctionnement hautes vitesses (produit (n×D_m) supérieur au million)
Rolling Element Bearing (REB) is an essential component in mechanical transmission to reduce friction between rotating parts. Now, with the development of electrical motor in mechanical industry, REBs may work at very high rotation speed. It leads to an increase of REB power losses and temperatures. Theses power losses are strongly coupled with the REB thermal behaviour. The oil temperature has a significant impact on the kinematic viscosity which in turn affects the REB power losses. Based on thermal network approach, an intermediate model is developed in this study. This new model allows obtaining lumped information (temperature of rings) with a minimum of input data (REB external geometry and operating condition only) and by using global power loss models. This intermediate model is developed for angular contact ball bearing and deep groove ball bearing under oil jet lubrication for high speed application. Experimental data are required to validate this new approach. That why, a modular test rig is designed to obtain information on the REB thermomechanical behaviour. The new test rig developed in this study is dedicated to a wide range of REB dimensions and for different operating conditions. For the first test, a deep groove ball bearing under oil jet lubrication is studied for high speed application ((N.dm) product is higher than one million.)

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17

Ashman, D. "High-speed performance of a hydrostatic thrust bearing." Thesis, University of Wolverhampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378961.

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The programme of research reported in this dissertation was undertaken with the aim of improving the high-speed performance of a multi-recessed hydrostatic thrust bearing. A theoretical analysis of the quasi-static behaviour and isothermal frictional power consumption is developed using the basic equations governing viscous fluid flow. The effects of high peripheral speeds are discussed and how recently proposed bearing modifications, in the form of grooved lands and changes in recess geometry, are used to reduce the frictional power consumption, lower operating temperatures, and reduce unwanted hydrodynamic and fluid inertia induced pressure variations. The steady state temperature distribution, frictional power consumption and operating clearance when one bearing member is rotating, and dynamic loading performance are predicted by several specially developed Fortran computer programs. One section concentrates on the design, development and instrumentation of an experimental multi-recessed hydrostatic thrust bearing, which had a facility for changing the pocket geometry using recess inserts. The bearing plate. which had an outside diameter of 200 mm, was operated at rotational speeds between 1000-5000 rpm to give peripheral speeds between 10.5 - 52.5 m/s. A chapter deals with an experimental investigation of the high-speed performance of a multi-recessed hydrostatic thrust bearing, principally the quasi-static loading and flow rate characteristics, temperature and pressure distributions and frictional power consumption. Furthermore, the dynamic response of the test bearing arrangement was investigated experimentally for a range of excitation frequencies between 0- 70 Hz- Finally, the theoretical predictions of characteristics such as quasi-static loading and flow rate, steady state operating conditions and dynamic response are compared with the corresponding experimental results.

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18

Nimir, Yassin Lutfi. "An air bearing system for high speed turbomachinery." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385143.

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19

Mondscehin, Brian David. "Evaluation of Alternate Bearing Designs in a High Speed Automotive Turbocharger." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/33513.

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Automotive turbochargers experience self-excited instabilities through the majority of their operating speed range. The results of these instabilities can cause damage to the bearings, shafts, and housing walls. Preventing this damage while maintaining or increasing performance characteristics is a huge concern to industry due to the time and money needed to replace vital components. The aim of this research is to determine which characteristics of the bearings have the greatest influence on the damped natural frequencies. It was believed that axial groove bearings could offer an acceptable alternative to the floating ring bearings currently found in automotive turbochargers. DyRoBeS rotor dynamics software was used to determine analytically damped natural frequencies for floating ring bearings, and also for six, eight, and ten axial groove fixed geometry bearings, under different speed and loading conditions. The resulting data were compared to experimental test results from an on-engine turbocharger test stand and presented in this report.
Master of Science

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20

Schneider, Abraham 1981. "Dynamic modeling of high-speed impulse turbine with elastomeric bearing supports." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/89911.

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21

Samadli, Vugar. "Rotor-bearing system dynamics of a high-speed micro end mill spindle." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0015756.

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22

Marais, Charl Henri. "High speed flexible rotor active magnetic bearing control / by Charl Henri Marais." Thesis, North-West University, 2006. http://hdl.handle.net/10394/1084.

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The School of Electrical, Electronic and Computer Engineering at the North-West University is in the process of establishing a knowledge base on Active Magnetic Bearings (AMBs). In support of this initiative this project is aimed at characterising an in-house developed double radial heteropolar AMB system. Before characterising the AMB system the acoustic noise problem of the system had to be addressed and reduced to an acceptable level. To reduce the acoustic noise of the system a noise analysis was done to determine the source of the noise. The analysis revealed radiated noise from the electromagnets and power amplifiers (PA) and conducted noise on the signals to and from the controller. The conducted noise is reduced by using anti-aliasing (AAF) and anti-imaging filters (AIF) before and after the controller. The effect of the radiated noise is reduced by synchronising the sampling of the sensor signals with the switching of the PAS. The characterisation of the AMB system starts with a Mass-Spring-Damper (MSD) simulation which is a linear representation of the AMB system. This simulation is used to understand the basic principles of a second order system and to compare its response to the nonlinear AMB simulation. The following step in characterising the AMB system is to determine the effect of filters on the nonlinear AMB simulation and to determine the simulation characteristics. These characteristics are compared to the MSD simulation and the actual AMB system. The characteristics compared between the MSD and AMB simulations are the static, second order and dynamic stiffness. The actual AMB system was characterised before and after the AAF and AIF were implemented. This provided the opportunity to determine the effects of the filters on the actual system and not just from simulations. The characteristics measured on the actual AMB system include the static stiffness, dynamic stiffness, rotor dynamics and system sensitivity. The stiffness characteristics of the actual AMB system showed good correlation with the linear and nonlinear simulations. The measured results showed a decrease in static stiffness and an increase in system sensitivity because of the AAF, AIF and controller pole. It also showed that the effects of the filters can be reduced by moving the controller pole to a higher frequency. The characterisation of the double radial heteropolar AMB system provides a fundamental understanding of the AMB performance aiding the AMB design process.
Thesis (M. Ing. (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2006.

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23

Alsaeed, Ali A. "A Study of Methods for Improving the Dynamic Stability of High-Speed Turbochargers." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/26664.

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The turbocharger industry is booming recently, and there is an urgent need for new evaluations of the overall design. As the oil prices continue to rise, along with the new emissions regulations strictly enforced for the in-road as well as the off-road vehicles, the transition to turbocharged engines, and especially for diesel engines, has become irresistible. Higher power, smaller engines, reduced emissions, and overall better efficiency are the main concerns. By means of the recent development in the computational tools, a new era of the product development has emerged. Most diesel engine turbochargers incorporate floating-ring bearings that use the engine's oil for lubrication. The high-speed turbocharger is known to have subsynchronous vibrations at high amplitudes for a wide speed range that could reach 150,000 rpm. The bearing fluid-film whirl instability is the main source of the subsynchronous vibration. The nonlinear reaction forces inside the bearings are usually causing the rotor to whirl in a limit cycle but may become large enough to cause permanent damages. Additionally, the lubrication oil may leak at higher rates through the seals into the engine or the exhaust emissions. This dissertation investigates methods for improving the dynamic stability of the high-speed automotive turbochargers, especially designed for heavy-duty diesel engines that are used for example in heavy machinery, trucks, tractors, etc. The study utilizes the available modern computational tools in rotor-dynamics in addition to the locally developed supportive computer codes. This research is a major part of the turbocharger dynamic analysis supporting the current extensive experimental tests in the Virginia Tech Rotor Dynamics Laboratory for the product development of different high-speed diesel engine turbochargers. The study begins with the method of enhanced-performance hydrodynamic bearings. The aim is to modify the inner surface of the bearing for better dynamic characteristics. The finite-element model of the turbocharger rotor shaft with linearized bearing dynamic coefficients is developed. The system is solved for eigenvalues and eigenvectors in order to evaluate the dynamic stability. The first phase of the study demonstrated that there are two modes of instability that persist during much of the operating speed range, and one of the modes exhibits serious subsynchronous vibration levels at the higher speeds. The first unstable mode builds up at very low speeds forming a conical shape, where both rotor shaft ends whirl forward out-of-phase. The second unstable mode has a cylindrical shape with slight bending, where both rotor ends whirl forward in-phase. The outcome of the study is that the inner surface of the bearing has direct influence on the turbocharger dynamic stability. However, a fixed hydrodynamic bearing may not give total linear stability of the system if it is used without additional damper. The second method is to analytically design flexible damped bearing-supports in order to improve the dynamic characteristics of the rotor-bearing system. The finite-element model of the turbocharger rotor with linearized bearing dynamic coefficients is used to solve for the logarithmic decrements and hence the stability map. The design process attempts to find the optimum dynamic characteristics of the flexible damped bearing-support that would give best dynamic stability of the rotor-bearing system. The method is successful in greatly improving the dynamic stability of the turbocharger and may also lead to a total linear stability throughout the entire speed range when used besides the enhanced-performance hydrodynamic bearings. The study also presents a new method for improving the dynamic stability by inducing the turbocharger rotor unbalance in order to suppress the subsynchronous vibrations. The finite-element model of the turbocharger rotor with floating-ring bearings is numerically solved for the nonlinear time-transient response. The compressor and the turbine unbalance are induced and the dynamic stability is computed. The turbocharger model with linearized floating-ring bearings is also solved for eigenvalues and eigenvectors to predict the modes of instability. The linear analysis demonstrates that the forward whirling mode of the floating-ring at the compressor end becomes also unstable at the higher turbocharger speeds, in addition to the unstable forward conical and cylindrical modes. The numerical predictions are also compared to the former experimental results of a typical turbocharger. The results of the study show that the subsynchronous frequency amplitude of the dominant first mode is reduced when inducing either the compressor or the turbine unbalance at a certain level. In addition to the study of the stability improvement methods, the dissertation investigates the other internal and external effects on the turbocharger rotor-bearing system. The radial aerodynamic forces that may develop inside the centrifugal compressor and the turbine volutes due to pressure variation of the circulating gas are numerically predicted for magnitudes, directions, and locations. The radial aerodynamic forces are numerically simulated as static forces in the turbocharger finite-element model with floating-ring bearings and solved for nonlinear time-transient response. The numerical predictions of the radial aerodynamic forces are computed with correlation to the earlier experimental results of the same turbocharger. The outcomes of the investigation demonstrated a significant influence of the radial aerodynamic loads on the turbocharger dynamic stability and the bearing reaction forces. The numerical predictions are also compared to the former experimental results for validation. The external effect of the engine-induced vibration on the turbocharger dynamic stability is studied. The engine-induced excitations are numerically simulated as time-forcing functions on the rotor-bearings of the turbocharger finite-element model with floating-ring bearings in order to solve for the nonlinear time-transient response. The compressor radial aerodynamic forces are combined to the engine-induced excitations to numerically predict the total nonlinear transient response. The results of the study show that there are considerable amplitudes at the engine-excitation frequency in the subsynchronous region that may also have similar amplitude at the second harmonic. Additionally, the magnitudes of the engine-induced vibration have an effect on the turbocharger dynamic stability. The numerical predictions are compared to the former experimental tests for turbocharger dynamic stability.
Ph. D.

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24

Dyson, John Edwin. "Aspects of the behaviour and design of dental high speed ball bearing air turbine handpieces." Thesis, University of London, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324587.

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25

Bailey, Nicola Y. "Analysis of dynamical performance and contact for a high speed thrust bearing including slip effects." Thesis, University of Nottingham, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.727115.

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Анотація:

Fluid-lubricated thrust bearing technology comprises two structural components, a rotor and stator separated by a thin fluid film experiencing relative rotational motion. The fluid film is employed to maintain a clearance between rotating and stationary elements when subjected to external axial loads. The fluid film lubrication mechanism is designed to provide an improved performance for applications characterized by high differential speed and requiring low frictional losses. An incompressible fluid flow model is derived for a parallel and coned thrust bearing using a modified Reynolds equation for the thin film dynamics of a stator and rapidly rotating rotor. Initially a no-slip boundary condition is imposed on the bearing faces. For high speed operation the lubrication approximation to the incompressible Navier-Stokes equations leads to a modified Reynolds equation incorporating rotational effects. The bearing dynamics are examined by coupling the fluid flow and axial motion of the rotor and stator; the rotor has prescribed periodic axial oscillations and the stator is modelled as a spring-mass-damper system, having axial motion in response to the film dynamics. To solve the modified Reynolds equation and stator equation simultaneously the time dependent minimum face clearance (MFC) variable is introduced, leading to the derivation of a non-linear second-order non-autonomous ordinary differential equation for the MFC. Applying a transient solver gives solutions of the MFC settling down to a stable periodic behaviour, motivating the derivation of a Fourier spectral collocation scheme.

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26

Garratt, John Edward. "Mathematical modelling of air-rotor-stator interactions in high-speed air-riding bearing and seal technology /." Thesis, University of Nottingham, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.580292.

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Air-riding bearing and seal technology comprises rotor and stator elements separated by a thin air-film and experiencing relative rotational motion. The Navier- Stokes equations for compressible flow lead to a modified Reynolds equation incorporating additional high-speed rotation effects. The dynamics of the system are investigated when the axial position of the stator is prescribed by a finite amplitude periodic forcing. Two different physical configurations of air-riding technology are considered in this thesis; a squeeze-film thrust bearing and a pressurised air-riding face seal. Details are provided of a finite-difference, time-stepping scheme and a Fourier spectral collocation scheme to compute the periodic pressure distributions and rotor heights. For changing values of a selected physical parameter the method of arc-length continuation is employed to track branches of solutions computed using the spectral collocation scheme. For both configurations of air-riding technology the effect of different frequencies and amplitudes of stator forcing is identified for a range of rotation speeds and the influence of the rotor support structures is analysed. For air-riding face seals a critical shaft speed is identified that maintains no-net flow by balancing inertia and pressurisation effects The potential for resonant rotor behaviour is identified through asymptotic and Fourier analysis of the rotor motion. Changes in the minimum rotor-stator clearance are presented as a function of the rotor stiffness to demonstrate the appearance of resonance. Both the minimum rotor-stator clearance and the total mass flux of air through the seal are used to evaluate the limits of stable periodic operation without resonant rotor dynamics and incorporating high operating speeds.

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27

Al-Ghasem, Adnan Mahmoud. "Measurement of rotordynamic coefficients for a high-speed flexure pivot tilting-pad bearing(load between pad) configuration." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2415.

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This thesis presents the dynamic and static forced performance of a flexure-pivot tilting-pad bearing load between pad (LBP) configuration for different rotor speeds and bearing unit loadings. The bearing has the following design parameters: 4 pads with pad arc angle 72o and 50% pivot offset, pad axial length 0.0762 m (3 in), pad radial clearance 0.254 mm (0.010 in), bearing radial clearance 0.1905 mm (0.0075 in), preload 0.25 and shaft nominal diameter of 0.11684 m (4.600 in). The dynamic coefficients and the static performance parameters of the FPB have been compared with the theoretical predictions using the isothermal analysis from the rotordynamic software suite XLTRC2-XLTFPBrg. The bearing shows a small attitude angle, about 10o, which indicates small crosscoupling stiffnesses. The pad temperatures increase in the circumferential direction of rotation with speed and load. The pads maximum temperature was measured near the trailing edge. The dependency of the stiffness and damping coefficients on the excitation frequency has been studied. The frequency dependency in the dynamic coefficients was removed by introducing an added mass coefficient to the bearing model. The direct added mass coefficients were around 32 kg. The direct stiffness and damping coefficients increase with load, while increasing and decreasing with rotor speed, respectively. A small whirl frequency ratio (WFR) was found of about 0.15, and it decreases with load and increases with speed. A comparison between the dynamic stiffnesses using a Reynolds equation and the bulk-flow Navier-Stokes models with the experimental dynamic stiffnesses shows that the Reynolds model (even for laminar flows) is not adequate, and that the bulk-flow model should be used for rotordynamic coefficients prediction. The bulk-flow model in general predicts well the static performance parameters and the direct dynamic coefficients, and underpredicts the cross-coupled coefficients (overpredicts the stability).

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28

Wroblewski, Adam C. "Model Identification, Updating, and Validation of an Active Magnetic Bearing High-Speed Machining Spindle for Precision Machining Operation." Cleveland State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=csu1318379242.

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29

Messager, Gael [Verfasser], Andreas [Akademischer Betreuer] Binder, and Ulrich [Akademischer Betreuer] Konigorski. "Self-bearing permanent magnet synchronous machine configurations and control for high-speed applications / Gael Messager ; Andreas Binder, Ulrich Konigorski." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2019. http://d-nb.info/1199006467/34.

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30

Lee, Trevor J. "Investigation of ASTM E 238 Bearing Pin Properties for Various Aerospace Alloys." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1074.

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Aircraft are often designed with numbers determined by testing in a lab, rather than by repeatedly building prototypes. These lab tests conform to testing specifications so that the numbers can be compared between manufacturers, suppliers, and lab technicians. One such specification is ASTM specification E238 – 84(08), and it is used to determine important properties of a bearing pin joint like hinges, bolt holes, and rivet joints. The properties determined from this fastener-through-plate method are bearing strength, bearing yield strength, and bearing stiffness. Adhering to the methods outlined in ASTM E238, a study was performed, looking at the effects that plate material, fastener used, fastener lubrication, and plate hole preparation method (whether drilled and reamed or just drilled) have on the three bearing joint properties. The plate materials used were Al 7050 – T7451, Ti – 6Al – 4V (mill annealed), and PH13 – 8Mo – H1000. The fasteners were Ti – 6Al – 4V screws, coated A286 screws, and high speed steel (HSS) pins used as a control. Lubrication was tested using a corrosion inhibitor, PR – 1776M B – 2 from PRC – DeSoto, on the fastener or leaving the fastener uncoated. The HSS pins were always tested in the uncoated condition. 54 runs were performed, as outlined by a D-optimal design of experiment. It was discovered from the statistical analysis of the results via ANOVA that both the plate material used and the pin material, whether a screw or a pin, had a significant effect on the bearing strength, bearing yield strength, and bearing stiffness. The interaction between the two factors was also significant on all responses but the bearing stiffness. PH13 – 8Mo – H1000 plates seemed to perform best on average, followed by Ti – 6Al – 4V plates, then Al 7050 – T7451 plates. PH13 – 8Mo – H1000 and Ti – 6Al – 4V plates had similar bearing strength and bearing yield strength averages with the HSS control pins being used, which had the highest mean values for a given plate and fastener. The Ti – 6Al – 4V and A286 screws behaved and performed statistically similar in most cases, except when hole preparation method was take into account. The Ti – 6Al – 4V screws performed better when the hole was drilled and reamed, while the coated A286 screws performed better when the hole was drilled only. All screws had lower resulting bearing properties than the HSS control pins. It was also found that ASTM specification E238 – 84(08) is a precise test method, since the method could be performed repeatably and reliably with no missing data points. Therefore, this ASTM testing method is reasonable for determining bearing properties, which can then be used to design aircraft.

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31

Calderon, Salmeron Gabriel Benjamin. "Enabling More Efficient E-Mobility : Grease Development by a Novel Bearing-Grease Test Machine." Thesis, KTH, Maskinkonstruktion (Avd.), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-259672.

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The inclusion of electric vehicles in the automotive industry represents an opportunity for lubricating grease producers. Different speed, loads, and electric conditions are present in the bearings of the electric vehicles when compared with the conditions in a traditional internal combustion engine vehicle. Therefore, the development of new grease formulations is desired to overcome these, and other challenges introduced by this new technology. This project aims to compare two grease-thickener technologies through the installation, development, and validation of a novel high-speed bearing-grease test HSBT machine. This rig allows emulating the conditions present in the bearings of an electric vehicle. In this thesis, 6208 deep groove ball bearings were used to compare the mechanical performance of the greases. The comparative study of lithium complex and polypropylene greases was performed through the analysis of the frictional moment and self-induced temperature of the tested grease-bearing combinations. The results present the energy-saving potential of both greases and show the feasibility of using the HSBT machine as a grease testing machine. This project is the first step in an ambitious plan of enhancing e-mobility through grease research. It gives the input for future development of the machine and the creation of new standards for testing electric vehicle greases.
Införandet av elfordon i bilindustrin utgör en möjlighet för smörjfettproducenter. Olika hastigheter, belastningar och elektriska förhållanden är närvarande i de elektriska fordonens kullager i jämförelse med förhållandena i ett traditionellt förbränningsmotorfordon. Detta kräver utveckling av nya fetter som kan hantera de utmaningar som uppkommer med denna nya teknik. Detta projekt ämnar jämföra två fettförtjockningstekniker genom att installera, utveckla och validera en ny höghastighetslagermaskin (HSBT-maskin) för smörjfettstestning. Denna maskin möjliggör att förhållanden som finns i lagren hos ett elektriskt fordon kan efterliknas. I denna masteruppsats användes spårkullager med beteckningen 6208 för att jämföra smörjfettens mekaniska prestanda. I denna studie jämfördes litiumkomplex- och polypropenfetter genom att analysera friktionsmomentet och den självinducerade temperaturen för de testade kullagersmörjfettskombinationerna. Resultatet av studien visar energibesparingspotentialen för båda smörjfetterna och visar möjligheten att använda HSBT-maskinen för att testa smörjfetter. Detta projekt är det första steget i en ambitiös plan att förbättra e-mobilitet genom smörjfettsforskning. Studien ger indata för framtida utveckling av elektriska maskiner och bidrar till skapandet av nya standarder för testning av fetter för elektriska fordon.

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32

Pavluš, Ondřej. "Návrh elektrodynamického magnetického ložiska." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442790.

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High speed applications demands with a need for lower energy consumption lead to designing new types of bearings. In the last decades magnetic bearing, which would be able to obtain passive stable levitation using regular materials at room temperature, has been searched. This has lead to development of electrodynamic bearing based on eddy currents principle. Currently the electrodynamic bearings are still not fully explored and further research is needed. The aim of the work is to describe the theory about modern magnetic bearing, analysis and design of electrodynamic bearing according to given parameters. The finite element method is used for further analysis and evaluate behaviour of its properties.

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33

Horn, Maik [Verfasser]. "Untersuchungen zur praktischen Umsetzung von Elastomer-Lagersitzen in Hochdrehzahl-Traktionselektromotoren : Studies for the practical implementation of elastomer supported bearing carriers in high-speed traction electric motors / Maik Horn." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2019. http://d-nb.info/1204458782/34.

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34

Lee, Seong-Ryeol, Florian Schoemacker, Christian Stammen, and Katharina Schmitz. "Numerical and experimental study on novel hydraulic pump concept." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71110.

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This paper discusses an investigation on a novel hydraulic pump concept. The idea aims on a pump principle to be directly connected to high-speed electric motors to build compact high-pressure drives. The pump can theoretically work without solid contact and has no kinematic pulsation. The composition of the pump is basically similar to cylindrical journal bearings. In general, a journal bearing is used to support external loads on a rotating shaft. When the shaft rotates with the loads, hydrodynamic fluid force is generated in the fluid film, which compensates the external force and reduces an eccentricity of the shaft. The difference of the introduced pump concept from the bearing is that the eccentricity is fixed and it has an outlet port at the high pressure area, through which the fluid can be transferred. To examine the functionality of the pump, a test bench is constructed and experiments are performed to investigate the pressure build-up and discharging flow of the pump concept. The experimental results are numerically analyzed by using elasto-hydrodynamic lubrication (EHL) simulation, based on the 2D Reynold’s equation. From these results, the functionality of the pump concept is confirmed. Moreover, several variables that influence the characteristic curve of the pump are studied. Based on these results, geometric parameters of the test pump are redesigned to discharge sufficient flow rate for usage as commercial pumps.

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35

Chen, Cheng-Yuan, and 陳政原. "Design of 5-DOF High Speed Spindle Supported by Magnetic Bearings." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/16763475358699444462.

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36

CHIOU, JIIN-HORNG, and 邱錦宏. "STUDY OF APPLICABILITY OF ISOLATION BEARINGS IN HIGH-SPEED RAILWAY BRIDGES." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/27882095666401916498.

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Анотація:

碩士
國立臺灣大學
土木工程學系
86
This study investigates the axial and vertical displacements of decks, base shear and moments of piers,axial stresses of rails at expansion joints and responses of bearings of high-speed railway bridges using lead rubber bearings and laminated rubber bearings to study the applicability of those bearings in high-speed railway bridges. This study relies mainly on numerical analysis. A finite-element analysis program is developed as the analysis tool. The models adopted and various parameters used are derived in the paper. The responses of high-speed railway bridges using bearings are analyzed and are compared to responses of those that are not equipped with bearings to study the applicability of bearings. The results show that the base shear and moments of high-speed railway bridges using lead rubber bearings subjected to acceleration and braking forces of vehicles,seismic loads and temperature loads are significantly reduced and displacements of decks and rail stresses remain roughly the same as those of high-speed railway bridges using hinges and rollers. Application of lead rubber bearings in high-speed railway bridges is considered applicable. And the excessive longitudinal displacements of decks using laminated rubber bearings subjected to acceleration and braking forces should be noted.

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37

吳明得. "Multilevel optimization of the high-speed spindle system with magnetic bearings." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/14164660800968411890.

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Анотація:

碩士
國立中正大學
機械系
89
ABSTRACT A design algorithm of single objective and/or multilevel optimization of a high-speed spindle system with magnetic bearings under critical speeds constraints are developed in this study. In the process of designing the high-speed spindle system, the weight of spindle and the vibration of tip cutter play very important roles on the performance of the high-speed spindle. Hence, the objective functions of optimization include the total weight of the spindle and/or the vibration of tip cutter. Consider the high-speed spindle system of this thesis, magnetic bearings are introduced to displace the ball bearing of the high-speed spindle system, which had been developed in the National Chung-Cheng University. To achieve the optimization approach, the system equations of motion are first derived from Lagrange Method and Finite Element Method (FEM). Then the system natural frequencies, mode shapes, and steady-state response are determined by the numerical analysis. Furthermore, from the influences of system parameters on the dynamic behaviors of the system, the radius of the outer shaft, the bias currents of the magnetic bearings, and the position of the bearings and disks, are considered as the design variables of optimization. According to the objective functions, both the optimization of single objective and multilevel objective optimization with critical speeds and/or bending stresses constraints are discussed. Thus, the optimization techniques employed are the Sequential Quadratic Programming Method (SQP) and the Goal Attainment Method (Att.Goal). The optimum results indicate that the total weight of the spindle and/or the vibration of the tip cutter of the high-speed spindle with magnetic bearings can be significantly reduced by single objective optimization or multilevel optimization under the critical speeds and/or bending stress constraints.

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38

Kasarda, Mary E. F. "The measurement and characterization of power losses in high speed magnetic bearings /." 1997. http://wwwlib.umi.com/dissertations/fullcit/9724685.

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39

Gao, Chih-Chung, and 高志忠. "The Performance of High-Speed Ball Bearings with Oil-Air Lubrication System." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/86494706958269375700.

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Анотація:

碩士
國立中正大學
機械工程學系
85
The ball bearing is widely used on many high speed rotating systems due to its low starting friction and high load capacity. However, heat generating and dynamic loading caused by high speed operation have been the limiting factors for increasing the speed limit of many high speed ball bearing applications. Therefore, how to provide proper lubrication and preload to reduce heat generation effectively are major task for high-speed ball bearing operation.Recently, oil-air lubrication has been used on high-speed ball bearing because of precise oil quantity control and high cooling efficiency. However, the fluctuation of oil supply resulted from the periodic oil feeding is unfavorable. In this study, the measuring equipment of fluctuation of oil supply was established. The operation parameters affecting stability of oil supply of oil-air lubrication system are experimentally studied. A test rig for high-speed ball bearings was also developed. The stable oil supply conditions obtained from preceding experiments is applied to bearing tests. The performance of high-speed ball bearing under different preload, running speed and oil flow rate has been investigated by measuring temperature rise and friction torque of test bearing.From this study, operating conditions that provide stable oil supply and good bearing performance were established. The effects of bearing preload on bearing temperature rise was also presented. It is also demonstrated that the high-speed ball bearing test rig built in this study provides a useful tool to develop lubrication technology for high-speed rotating system.

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40

Tsai, Shui-Fa, and 蔡水發. "Analysis of the Electromagnetic Forming for Small and High Speed Hydrodynamic Bearings." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/05040568992994217737.

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Анотація:

碩士
國立雲林科技大學
機械工程系碩士班
91
For the increasing of small and high-speed motor requirement in electronic productions, the characteristics, low friction, low noise, and high speed, etc., of hydrodynamic bearings could satisfy the conditions. For this reason, hydrodynamic bearings are often used in disc drive or other rotational parts. The hydrodynamic bearing has a number of herringbone grooves on the inner diameter of the sleeve. Once the shaft starts to run, the grooves take in oil from each end of grooves and push it into the central part to produce pressure. Because of the sleeve and the shaft are not in contact. The hydrodynamic bearings offer several advantages such as high speed, low friction and low noise. There are some great advantages of using Electromagnetic forming, such as high speed, good repeatable, low springback, inexpensive, small size and high flexibility. Electromagnetic forming could be developed to manufacture the grooves of hydrodynamic bearing in high speed. The objective of this study is to discuss the effect of various parameters in fabrication of hydrodynamic bearings via the commercial FEM code DEFORM-3D. From the results of simulation, the electric parameters could be evaluated for forming need.

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41

Wang, Yan-Hsin, and 王彥欣. "Design and characteristic analysis of high speed spindle aerostatic circular double pad thrust bearings." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/46126537013464007358.

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Анотація:

碩士
國立彰化師範大學
工業教育學系
89
The purpose of this paper is to make an investigation on the circular aerostatic thrust bearing with grooves and with different diameters presented by describing numerical methods in which Reynolds’ equation is solved in finite element form and on the other way the resistance network method (R.N.M.) based on the concept of flow continuation is obtained. The theoretical model developed is capable of calculating the pressure distribution in the gas-lubricated film and the load-carrying capacity as a separating force. Beside, to analyze the behavior on double-pad thrust bearing with eight restrictors for the high-speed spindle, and to estimate the pressure distribution in considered thrust bearing, numerical calculations were presented by the R.N.M. based on the concept of flow continuation. The coincidence of results derived from the R.N.M. and the F.D.M. based on the Reynolds’ equation has been proved. Finally, the aerodynamic effect caused by the high rotating speed of the spindle will be taken into account. The characteristic of load capacity is influenced by the spindle weight and the bearing inclination.

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42

LI, JHE-YUAN, and 李哲淵. "Preparation and Design of The Magnetic Fluid and Magnetic Bearings on Ultra High Speed Seals." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/99pgvp.

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43

-Yi, Ji, and 黃吉毅. "Modeling and Recognition of the Temperature Rise on the Bearings of the High-Speed Spindle System." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/77073382881215551669.

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Анотація:

碩士
國立高雄第一科技大學
機械與自動化工程所
97
The purpose of the thesis is to develop a forewarning system for indicating the abnormal temperature rise and vibration behavior of the bearing in the high-speed spindle in a motor system. As generally speaking, without well releasing the heat generated under the operation of a motor, the heat will seriously cause the rigidity degradation and aging on the bearing.Therefore, we have to do the calorific capacity analysis of the bearing under operating status,and then to build a more realistic model for simulating the temperature rise curve and the vibration behavior. In our purpose, we want to design a forewarning system to avoid the system operate out of the safety temperature range and to indicate the abnormal variation in advance. However, the mathematical model constructed out of the ideal geometric kinetics and thermodynamics is not enough for simulating the real motion of the bearing in the high-speed spindle system. Therefore, we monitor and record the temperature rise curve and vibration behavior of the bearing in the high-speed spindle system, and then input all the data into the back-propagation neural networks for simulation calculation. Then, we compare the temperature and vibration of the bearing monitored immediately with the simulated data out of the back-propagation neural networks calculation. When the deviation of the temperature or vibration is out of the safety range, our forewarning system constructed out of the fuzzy inference will deliver an alarm to users to protect the bearing against the damage from heat.

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44

Lawrence, Tom Marquis. "Characterization and Measurement of Hybrid Gas Journal Bearings." 2012. http://hdl.handle.net/1805/2926.

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Indiana University-Purdue University Indianapolis (IUPUI)
This thesis concentrates on the study of hybrid gas journal bearings (bearings with externally pressurized mass addition). It differs from most work in that it goes back to “basics” to explore the hydrodynamic phenomena in the bearing gap. The thesis compares geometrically identical bearings with 2 configurations of external pressurization, porous liners where mass-addition compensation is varied by varying the liner’s permeability, and bushings with 2 rows of 6 feedholes where the mass-addition compensation is varied by the feedhole diameter. Experimentally, prototype bearings with mass-addition compensation that spans 2 orders of magnitude with differing clearances are built and their aerostatic properties and mass addition characteristics are thoroughly tested. The fundamental equations for compressible, laminar, Poiseuille flow are used to suggest how the mass flow “compensation” should be mathematically modeled. This is back-checked against the experimental mass flow measurements and is used to determine a mass-addition compensation parameter (called Kmeas) for each prototype bushing. In so doing, the methodology of modeling and measuring the mass addition in a hybrid gas bearing is re-examined and an innovative, practical, and simple method is found that makes it possible to make an “apples-to-apples” comparison between different configurations of external pressurization. This mass addition model is used in conjunction with the Reynolds equation to perform theory-based numerical analysis of virtual hybrid gas journal bearings (CFD experiments). The first CFD experiments performed use virtual bearings modeled to be identical to the experimental prototypes and replicate the experimental work. The results are compared and the CFD model is validated. The ontological significance of appropriate dimensionless similitude parameters is re-examined and a, previously lacking, complete set of similitude factors is found for hybrid bearings. A new practical method is developed to study in unprecedented detail the aerostatic component of the hybrid bearings. It is used to definitively compare the feedhole bearings to the porous liner bearings. The hydrostatic bearing efficiency (HBE) is defined and it is determined that the maximum achievable hydrostatic bearing efficiency (MAHBE) is determined solely by the bearing’s mass addition configuration. The MAHBE of the porous liner bearings is determined to be over 5 times that of the feedhole bearings. The method also presents a means to tune the Kmeas to the clearance to achieve the MAHBE as well as giving a complete mapping of the hitherto misunderstood complex shapes of aerostatic load versus radial deflection curves. This method also rediscovers the obscure phenomenon of static instability which is called in this thesis the “near surface effect” and appears to be the first work to present a practical method to predict the range of static instability and quantify its resultant stiffness fall-off. It determines that porous liner type bearings are not subject to the phenomenon which appears for feedhole type bearings when the clearance exceeds a critical value relative to its mass-addition compensation. The standing pressure waves of hydrostatic and hybrid bearings with the 2 configurations of external pressurization as well as a geometrically identical hydrodynamic bearing are studied in detail under the methodology of the “CFD microscope”. This method is used to characterize and identify the development, growth, and movement of the pressure wave extrema with increased hydrodynamic action (either increasing speed or increasing eccentricity). This method is also used to determine the “cause” of the “near surface effect”. A gedanken experiment is performed based on these results which indicates that a bearing with a “stronger aerostatic strength” component should be more stable than one with a low aerostatic strength component. Numerical instability “speed limits” are found that are also related to the hydrostatic strength of the bearing. The local conditions in the standing waves are characterized in terms of their local Mach number, Knudsen number, Reynolds number, and Taylor Number. It is concluded that low eccentricity bearing whirl can be attributed to the off load-line orientation of the bearing load force caused by the overlay of the hydrodynamic bearing standing wave onto the hydrostatic bearing wave of the hybrid bearing, whereas it is hypothesized that aperiodic and random self-excited vibration which occurs at high eccentricity, as reported in the literature, is probably due to shock waves, turbulence, near surface effect, and slip at local areas of the standing wave.

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45

Yang, Pe-Hn, and 楊培亨. "Application of Taguchi Method to Roubust PID Controller Design for 5-DOF High Speed Spindle Supported by Magnetic Bearings." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/41446507171027652818.

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Анотація:

碩士
國立交通大學
機械工程研究所
85
The dynamic characteristics of magnetic bearings are often suffered from many problems, such as nonlinearities, parameter variations and external disturbances. To solve these problems, we applied Taguchi method associated with the decentralized control to design a decentralized PID controller with robustness. The results show that the performance of the decentralized PID controller system is better than that of the decentralized PD control system in the ability of suppressing the external force except that chattering effect exists in the responses. 　　In the study, the Taguchi method is employed to determine beast parameters in control rules for a decentralized PID control method. Two major characteristics of the Taguchi method are, firstly, the use of total possible combinations to estimate the main factor effect and some, not all, of the interaction. Secondly, signal-to-noise (S／N) ratios are used to evaluate the system performance of a system in the presence of noise factor, so that the performance can be made insensitive to noise factor. For control systems with uncertainty, the Taguchi method is found to be effective to improve system performance. 　　Finally, we developed a current driver circuit for a high speed spindle with five degrees of freedom supported by magnetic bearings. The prototype is tested under various operating conditions. We found that the control performance fulfills our design specifications, which directly verify our design methodology.

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46

Віцюк, Юлія Юріївна. "Забезпечення довговічності підшипників ковзання на основі міді та нікелю для удосконалення поліграфічних машин". Doctoral thesis, 2011. https://ela.kpi.ua/handle/123456789/829.

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47

Lee, Yu-Han, and 李育翰. "Performance Analysis of High Speed Spindle Aerostatic Bearing." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/33149677830761626847.

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Анотація:

碩士
國立成功大學
機械工程學系
89
In the study of gas bearing, how the pressure distribution and the precision of bearing rotation are precisely calculated is an important material for gas bearing design. In this work the theory and the precise analysis of bearing performance are presented. First, the mathematical model of gasflowing condition in the bearing is constructed. After the derivation and the simplification from Navier-Stoke Equation resulting the expected Reynold’s Equation. The combination of continuous equation and flow equation of orifice throttle is then substitute into Reynold’s Equation. Finally The resulting revised nonlinear Reynolds Equation with dimensionless is discretized by, using Newton’methed. The revised numerical iteratived method is then dopted to solve the problem. This method can be used to simulate the high eccentricity ratio journal, the high-speed noncircular journal, the thrust bearing and the non-plane slide bearing, etc.. The analysis can be treated as the fundamental to construct the performance analysis gas bearing. The performance of the static- and dynamic-pressure gas bearing can be analyzed by the constructed numerical model. It includes the analyses of film pressure distribution, friction, loading capacity, rigidity, flow rate of lubricative gas, and eccentricity ratio, etc.. With the appropriate design of precise rotating bearing, the results of this study could be provided as the fundamental of optimized design and analysis of bearing.

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48

Chou, Lin-En, and 周麟恩. "Kinematic and Dynamic Analysis of High speed bearing system." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/11598946158393074505.

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Анотація:

碩士
國立中山大學
機械工程學系研究所
89
The aim of this thesis is to analyze the kinematic and dynamic characteristics of a high-speed bearing system. The examined kinematic characteristics will include the maximal speed, fatigue life and stiffness of a bearing system. The stability and transmission force of a bearing system as well as the vibration of its shaft were the studied dynamic characteristics. These analyses were based on the kinemitics of bearing systems, rotor dynamics and elastohydrodynamic lubrication theory. According to these analyses, the interaction and consequence among these characteristics and the parameters of a bearing system will be explained. After these analyses, preliminary and simple design trends about a high-speed bearing system are going to be proposed.

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49

Chang, tou koan, and 張圖寬. "Multiobjective Optimization of Rotor-Bearing System of High Speed Spindle." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/77709802722415909977.

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Анотація:

碩士
國立中正大學
機械工程學系
85
The dynamic behavior and optimum design of rotor-bearing system of high speed spindle are studied in this thesis. It consists of the outer shaft and the inner shaft. The outer shaft is composed of the center shaft and the rotor of AC motor. And the inner shaft is the tool holder. The outer shaft is joined together with the inner shaft via two join points. The dynamic behavior of the rotor-bearing system is modeled by the finite element method. Then the system natural frequencies are determined by the numerical analysis. Because the mass of the outer shaft may be much greater than that of the inner shaft, the single rotor-bearing system is also used to compare the behavior of the dual rotor-bearing system. The system natural frequencies are measured to compare the numerical results. Furthermore, the system steady-state response is also studied. In optimization, the Augmented Lagrange Multiplier Method (ALMM) and Modified Method of Feasible Direction (MMFD) of mathematical programming method are applied in this study. Also, both the single objective optimization and the multiobjective optimization are performed and the optimum results are compared. The optimum results indicate that the steady-state response at the front bearing and/or the transmitted forces through the bearings can be significantly reduced by single objective optimization or multiobjective optimization.

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50

Chen, Yubao. "Dynamic analysis and diagnostic monitoring for high speed spindle-bearing structures." 1986. http://catalog.hathitrust.org/api/volumes/oclc/15692404.html.

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Анотація:

Thesis (Ph. D.)--University of Wisconsin--Madison, 1986.
Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 250-257).

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