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Ding, Huali. "Dynamic wear models for gear systems." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1194025602.
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Wilkinson, Christian Marco Raymond. "The durability of highly loaded, case hardened steel gears." Thesis, Imperial College London, 1998. http://hdl.handle.net/10044/1/8725.
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Chitta, Sudeendra. "Elastohydrodynamic lubrication in spur gear and helical gear contacts." Thesis, KTH, Maskinkonstruktion (Avd.), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-151246.
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The gears in a transmission are lubricated to prevent their premature failure as a result of pitting and wear on the tooth surfaces. Furthermore, the lubricant also limits the rise in surface temperature of the gears, which could otherwise lead to failure as a result of scuffing. The purpose of this thesis was to construct a fairly realistic theoretical lubrication model for spur and helical gears, the primary output parameters of this model being film thickness and flash temperatures, which would help in the identification of areas on the gear tooth surface prone to the aforementioned modes of failure. This thesis was carried out at the Gear Technology group in Scania CV AB in collaboration with the department of machine design at KTH. Gear lubrication is tricky as it entails the determination of parameters such as loads, curvatures, and velocities; which are different along the entire surface of the gear tooth. Primarily the loads are hard to obtain as they are dynamic in nature; the load is shared between different pairs of teeth during motion. The calculation of velocities and curvatures in an area of the gear surface called the tip relief can also not be done in a straightforward manner. These issues were simplified to a large extent with the assistance of a program called Helical 3D; owing to its powerful contact analysis algorithm, values of the film thickness and flash temperatures could be determined in almost every region where contact occurred between the gear teeth. The results of the lubrication model showed a reduction in film thickness in the tip relief area of the gear tooth surface; which meant that there were higher chances for the incidence of pitting and wear in this region. This was later confirmed when photographs from experimental tests illustrated a pitting line in the tip relief region of the helical gear. It was also inferred from the model that the occurrence of pitting could be greatly reduced if a quadratic tip relief modification were applied when compared to the existing linear modification used at Scania. Another important conclusion drawn was that thermal effects contributed to a significant decrease in the film thickness. Furthermore, the model showed higher flash temperatures close to the tip of the gear tooth surface, and photographs from experiments conducted showed the prescence of scuffing marks there.
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Xinmin, Li. "Efficiency and wear properties of spur gears made of powder metallurgy materials." Doctoral thesis, KTH, Maskinkonstruktion (Inst.), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187446.
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Powder metallurgy (PM) is usually used in manufacturing parts with complex geometries, such as gears and structural parts. The main attractions of PM are the high rate of material utilization, environmental friendliness of production, economic advantages (especially for complex geometries), and possibility of obtaining lighter components. To find a wide range of applications and compete with regular steel gears, PM gear transmissions should have good transmission efficiency and wear properties. Furthermore, they should have low contact noise and adequate surface fatigue properties. Because of the porosity structure of PM gears both on gear flanks and in the body, the friction and wear properties of PM gear flank contacts differ somewhat from those of regular steel gears. This doctoral thesis examines the efficiency and wear properties of PM gears. Paper A compares the wear, friction, and damage mechanism properties of two sintered gear materials with those of a standard gear material. Paper B deals with the gear mesh torque loss mechanism of PM and regular steel gears by combining both pin-on-disc frictional and FZG efficiency tests. Paper C comparatively examines the efficiency of PM and regular steel gears by conducting FZG gear efficiency tests. Paper D focuses on the wear and friction properties of PM and regular steel gear materials treated using the triboconditioning process. Paper E studies the friction and wear properties attributable to different pore sizes in PM gear materials. The results indicate that regular steel meshed with PM gear material and PM meshed with PM gear material are good candidate combinations for gear transmissions. This is because the porosities of PM material can lower the friction coefficient while the wear rate can be the same as or even better than that of regular steel contacts. The triboconditioning process enhances the wear resistance and reduces the friction coefficient of the PM gear material. The friction and wear coefficients of PM meshed with PM gear material display increasing trends with increasing pore size. The friction and wear coefficients of regular steel meshed with PM gear material display decreasing trends with increasing pore size.QC 20160523
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Alroqi, Abdurrhman Atig. "Investigation of the heat and wear of aircraft landing gear tyres." Thesis, University of Sussex, 2017. http://sro.sussex.ac.uk/id/eprint/68761/.
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In aircraft, the main landing gear wheels skid on the runway at the moment of touchdown because of high slip. A slipping tyre generates enough heat to melt its rubber. Melted rubber is easily eroded by the friction force between the tyre and runway; and part of eroded rubber stays on the runway, and other is burnt off as smoke. Since the early days of airplane use, a number of ideas have been patented to improve tyre safety and decrease the substantial wear and smoke during every landing by spinning the gear wheels before touchdown. In this thesis, there are three parts of research work. First part is to find the effectiveness of the technique of pre-spinning the wheel to reduce the tyre tread heat and wear, and then choosing the initial wheel rotation speed that prevent the tread rubber from melting temperature. For achieving this, a coupled structural – thermal transient analysis in ANSYS has been used to model a single wheel main landing gear as a mass-spring system. This model has been chosen to analyze the wheel's dynamic behaviour and tyre tread temperature and wear during the short period from static to a matching free-rolling velocity in which the wheel is forced to accelerate by the friction between the tyre and ground. The tyre contact surface temperature and wear have been calculated for both the initially static and pre-spun wheels in order to compare the temperature and wear levels for different initial rotation speeds. In the second part, the required torque to spin the aircraft wheel to the required angular speed at approach speed has been calculated using ANSYS CFX, which is used to determine the wheel aerodynamic forces developed by simulation of fluid flows in a virtual environment. In the last part, several types of wind turbines have been simulated.
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Park, Daehyun. "Development of Surface Wear and Lapping Simulation Models for Hypoid Gears." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1251739728.
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Bergseth, Ellen. "On tribological design in gear tooth contacts." Doctoral thesis, KTH, Maskinelement, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102742.
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The correct tribological design will have a considerable effect on a gear’s service life and efficiency. The purpose of this thesis is to clarify the impact of variation in the gear tooth flank tribological system on the gear contact load capacity – to increase the understanding of how surface topography and lubricant interact. In this thesis the variation in surface topography inherent in the manufacturing method has been shown, by experimental work and computer simulations, to be an important factor for the contact condition in the early life of gears. Surface analysis revealed that the formation and composition of surface boundary layers depends strongly on the chemical composition of the lubricant, but also on pre-existing surface boundary layers. Additionally, surface boundary layers play a major role in frictional behaviour, wear and in allowing the lubricant to react properly with the surfaces. Paper A presents the current ISO 6336 calculation of surface durability. A robust design approach was used to investigate the extent to which the current standard for calculation of surface durability allows for manufacturing variations and the choice of lubricant. Paper B investigates the extent to which a logarithmical profile modification can increase gear contact pressure robustness compared to traditional lead profiles for gears. Paper C compares different gear manufacturing methods and their as-manufactured (fresh unworn) surface topographies, using measured surface topographies as input to a contact simulation program. Paper D examines surface boundary layer formation and the corresponding wear in relation to different anti-wear additives in an environmentally adapted base oil. Papers E and F make use of specimens with surface topographies imitating two gear manufacturing methods (grinding and superfinishing) to be used in a twin-disc and barrel-on-disc machine respectively. The contacts are analysed by friction measurements and simulations combined with methods for surface analysis.QC 20120925
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Brauer, Jesper. "Investigation of transmisison error, friction and wear in anti-backlash involute gear transmissions." Doctoral thesis, KTH, Machine Design, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3590.
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Ding, Huali. "A study of interactions between dynamic behavior of gear systems and surface wear." The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1194025602.
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Mat, Dan Reduan. "Multi-view and three-dimensional (3D) images in wear debris analysis (WDA)." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/multiview-and-threedimensional-3d-images-inwear-debris-analysis-wda(534bc7ed-ef5f-489d-b9d2-4fe89b975b61).html.
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Wear debris found in gear lubricating oil provides extremely valuable information on the nature and severity of gear faults as well as remaining gear life. The conventional off-line process of taking samples of oil for testing of wear debris is a hindrance because it is laborious, expensive, delays information collection, and is expert oriented. In view of these limitations, the development of automating wear debris particle analysis using various approaches has been ongoing for years. However, existing online technology does not encourage widespread use of wear debris analysis (WDA) in the industry. High costs coupled with expert and labour requirements have led users to use other types of condition-based maintenance, such as vibration. There is a need to develop a WDA technique that is relatively cheap, online, requires little expertise to handle, and provides more information for maintenance decision-making. This PhD thesis proposes a WDA technique which uses image processing and three-dimensional image reconstruction to diagnose the health of machinery. Its emphasis is on using the thickness and volume of the particles generated over time to predict the onset of gearbox failure, so that maintenance action can be taken before gears reach catastrophic failure.
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Domare, Emma. "Generating gear grinding : An analysis of gringing parameters's effect on gear tooth quality." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-68637.
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Generating gear grinding is a method used for hard machining of gearbox gears. It facilitates a productive gear manufacturing with tight tolerances regarding surface roughness and geometrical accuracy. However, if the grinding is done with incorrect parameters, so called grinding burns can arise with consequences such as changes in surface hardness, changes in residual stress levels, surface embrittlement and compromised fatigue strength. This thesis investigates the gear tooth quality resulting from grinding parameters contributing to an improved grinding time. A literature study will cover gear geometries and material, grinding wheel properties, influences by grinding parameters and several verification methods. An experimental test will then be used to put four different grinding parameters to the test. The results showed that an increased cutting speed indicated finer surface roughness andincreased Barkhausen noise but showed no influence on gear geometry. Increasing both rough and fine feed rates resulted in a minor increase in geometry deviation but no significant difference in surface roughness. Large variations within the different verification method results related to grinding burns madeit difficult to draw conclusions regarding the experimental factors chosen. However, several factors apart from the experimental ones varied in the testing were believed to have significant influence, such as the flow of the cooling fluidand the amount of retained austenite from the carburizing process. In fact, the trends which seemed to be connected to these factors could be seen in both Barkhausen noise analysis, hardness measurementsand microstructure.
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Liou, Joe J. "A Theoretical and Experimental Investigation of Roller and Gear Scuffing." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1273007485.
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Kong, Qianyin. "Calibration and Estimation of Dog Teeth Positions in Synchronizers for Minimizing Noise and Wear during Gear Shifting." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-282763.
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Electric motors are used more widely in automotive to reducing emissions in vehicles. Due to the decreased usage of internal combustion engines which used to be the main noise source, impacts from synchronizers cannot be ignored during gear shifting, not only causing noise and wear but also delaying gear shifting completion. To minimize the impacts during gear shifting, a dog teeth position sensor is required but the high calculation frequency leads to a high cost, due to the high velocity of synchronizer portions and the dog teeth number. In this thesis, the gear shifting transmission is being modelled, in order to study the process of gear shifting and engagement. The transmission model, which is expressed with electrics and dynamics formulations. In order to avoid the impact without the dog teeth position sensor, this thesis proposes an estimation algorithm based on the transmission model to approve the gear engagement if the first and second portions of synchronizers are engaged in the mating position without impacts. Two different learning algorithms: direct comparison and particle swarm optimization application, are presented in the thesis as well, which are used to calibrate a parameter in the off-time test as part of the end of the calibration line, the so-called relevant initial phase being used in the real-time estimation. The transmission model is simulated in Simulink and different algorithms are running in MATLAB. All these results are plotted and analyzed for further evaluation in different aspects in the result chapter. The direct comparison algorithm has a simpler structure of computation but the quantity of required actuation is uncertain in this algorithm with a probability of failure to find the solution. The application of particle swarm optimization in this case succeeds in calibrating the objective parameter with a small error than the other algorithm. Actuation quantity affects the accuracy of the solutions and errors but not the failure rate.Elektriska motorer används i allt större utsträckning inom fordonsindustrin för att minska utsläppen från fordon. Den minskade användningen av förbränningsmotorer, som tidigare varit den främsta bullerkällan, gör att kollisioner från synkroniserare inte kan bli ignorerade under växlingen. Dessa kollisioner orsakar inte bara buller och nötningar utan även fördröjer slutförandet av växlingen. För att minimera kollisioner under växlingen krävs det en positionssensor för dog-teeth, men den höga beräkningsfrekvensen leder till hög kostnad på grund av den höga hastigheten hos synkroniseringsdelarna samt antalet dog-teeth. I den här avhandlingen görs en modell av växellåda för att studera växlingsprocessen och kugghjulsingreppet. Transmissionsmodellen uttrycks med elektriska och dynamiska formuleringar. För att undvika kollisioner utan positionssensor för dog-teeth, föreslås det en uppskattningsalgoritm baserad på transmissionsmodellen för att godta kugghjulsingreppet om den första and andra delen av synkroniseraren är inkopplade i parningsläget utan kollisioner. Två olika inlärningsalgoritmer, direkt jämförelsemetoden och partikelsvärmoptimeringsmetoden presenteras även i avhandlingen. De används för att kalibrera en parameter i off-time test som en del av slutet av produktionslinjen. Denna parameter kallas för den relevanta initialfasen och används vid realtidsuppskattningen. Transmissionsmodellen är simulerad i Simulink och de olika algoritmerna exekveras i Matlab. Alla resultat är plottade och analyserade för vidare utvärdering av olika aspekter i resultatkapitlet. Den direkta jämförelsealgoritmen har en enklare beräkningsstruktur, men mängden av nödvändig exekveringar är oklar för denna algoritm med en sannolikhet att det inte går att hitta lösningen. Däremot visar det sig att partikelsvärmoptimeringsmetoden lyckas med att kalibrera målparametern med dessutom ge mindre fel än den andra algoritmen. Antalet exekveringar påverkar lösningen samt noggrannheten hos lösningarna men påverkar inte själva felfrekvensen.
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Hoseini, Saba. "Experimental simulation of gear hobbing through a face milling concept in CNC-machine." Thesis, KTH, Materialvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-126804.
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Shon, Samuel. "An Experimental Study on the Impact of Various Surface Treatments on Friction, Scuffing, and Wear Characteristics of Lubricated Rolling-Sliding Contacts." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1351629351.
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Harpster, Steven. "A Feasibility Study on Development of Dust Abrasion Resistant Gear Concepts for Lunar Vehicle Gearboxes." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1236365431.
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Wilson, Steve Jason. "Traction and Wear Evaluation of a Number of Plastic Materials and Greases under Combined Rolling and Sliding Contact Conditions." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337191253.
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Gerth, Julia Lundberg. "Tribology at the Cutting Edge : A Study of Material Transfer and Damage Mechanisms in Metal Cutting." Doctoral thesis, Uppsala universitet, Tillämpad materialvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-183186.
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The vision of this thesis is to improve the metal cutting process, with emphasis on the cutting tool, to enable stable and economical industrial production while using expensive tools such as hobs. The aim is to increase the tribological understanding of the mechanisms operating at a cutting edge and of how these can be controlled using different tool parameters. Such understanding will facilitate the development and implementation of future, tribologically designed, cutting tools. Common wear and failure mechanisms in gear hobbing have been identified and focused studies of the material transferred to the tool, in both metal cutting operations and in simplified tribological tests, have been conducted. Interactions between residual stresses in the tool coating and the shape of the cutting edge have also been studied. It was concluded that tool failure is often initiated via small defects in the coated tool system, and it is necessary to eliminate, or minimize, these defects in order to manufacture more reliable and efficient gear cutting tools. Furthermore, the geometry of a cutting edge should be optimized with the residual stress state in the coating, in mind. The interaction between a compressive stress and the geometry of the cutting edge will affect the stress state at the cutting edge and thus affect the practical toughness and the wear resistance of the coating in that area. An intermittent sliding contact test is presented and shown to be of high relevance for studying the interaction between the tool rake face and the chip in milling. It was also demonstrated that material transfer, that can have large effects on the cutting performance, commences already after very short contact times. The nature of the transfer may differ in different areas on the tool. It may include glassy layers, with accumulations of specific elements from the workpiece, and transfer of steel in more or less oxidized form. Both tool coating material, its surface roughness, and the relative speed between the tool surface and the chip, may influence the extent to which the different transfer will occur.
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Hasan, Mushfiq. "Investigation of micropitting and wear in rolling/sliding contacts operating under boundary lubrication conditions." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-87215.
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Stenudd, Joakim. "Development of method for early fault detection in small planetary gear sets in nutrunners." Thesis, Luleå tekniska universitet, Maskinelement, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-83227.
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The objective of this thesis work was to develop a method to detect early damage on small planetary gear sets that are installed in Atlas Copco nutrunners. The project has gone through several stages of product development, from idea to working product and signal analysis. Currently, Atlas Copco have a test rig for testing these planetary gears, this rig has been proven to be insufficient at detecting faults during an ongoing test. A new tailored test rig was therefore designed and manufactured. Low noise and low amount of vibration was of interest when designing the rig. Four concepts was thought of and evaluated through simulations using Matlab and Simulink. Most of the components of the rig were manufactured in the workshop at Atlas Copco in Nacka. Methods fo rmeasuring torsional, transverse and acoustic vibration was implemented and analyzed. There are many different parameters considering fault of fixed shaft gears. However, these are not easily applicable on a planetary gear because of the nature of its design. Therefore, special techniques are required. Two “new” parameters were tested (NSDS,FRMS [Lei. et al.]) with positive results. Pitting of individual gear members could befound.
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Lejonklo, Caroline. "Friction and wear study of lean powder metallurgy steel in a lubricated sliding contact." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-390557.
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A fairly new technology used to produce metallic components is powder metallurgy (PM). Among the advantages with this technique are decreased cost of production for complex-shaped parts, new alloys are made possible, reduced end processing, less material loss, and vibrational damping effects. The downside is the number of pores created which can alter the tribological properties of the material. The focus of this report is to investigate how lean PM steel behaves under tribological contacts. Friction and wear will be investigated using a pin-on-disc setup to mimic the sliding part of a gear tooth mesh. Previous studies show that the amount of wear, and if the wear increases or decreases with increased density is dependent on the degree of porosity and the pore size. This means that the wear might be minimized by optimizing the number of pores in the material and their shape and size. The result of this study shows that the friction coefficient decreases with increasing density. The wear coefficient show signs of the same correlations but further tests are needed. The main wear comes from adhesive wear, with signs of abrasive wear. The amount of abrasive wear seems to increase with an increase in density, supporting previous studies claiming that pores can trap wear debris and decrease the number of abrasive particles in the contact.
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Lago, Daniel Fabiano [UNESP]. "Manutenção de redutores de velocidade pela integração das técnicas preditivas de análise de vibrações e análise de óleo lubrificante." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/94548.
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Todo sistema ou equipamento mecânico está sujeito a processos de deterioração. Esta deterioração leva ao aparecimento de defeitos que podem atrapalhar a continuidade e qualidade do serviço (produção). Uma quebra não prevista traduz-se por uma parada brusca, levando geralmente a grandes prejuízos e a perda de tempo de produção. Para evitar paradas inesperadas eficientemente e reduzir os custo de manutenção são utilizadas técnicas de manutenção preditiva. Entre todas as técnicas existentes, as mais importantes na manutenção de redutores são a análise de vibrações e a análise de partículas de desgaste. A determinação da severidade, modos e tipos de desgaste em máquinas pode ser feita pela identificação da morfologia, acabamento superficial, coloração, natureza, quantidade e tamanho das partículas encontradas em amostras de óleo ou graxas. Pela análise do sinal vibratório é possível tomar decisões de intervir ou não na operação da máquina, aumentando a disponibilidade e confiabilidade da mesma. A integração destas técnicas tem o potencial para revolucionar práticas industriais e proporcionar para as companhias um significante alívio econômico. Para estudo destas duas técnicas, neste trabalho foi construída uma bancada experimental com o propósito de se realizar a manutenção preditiva em um redutor de velocidades. O Sistema foi posto para funcionar até o limite de utilização. Foram utilizados lubrificantes recomendados pelo fabricante do redutor, lubrificantes com contaminação líquida em várias porcentagens e lubrificantes com contaminação sólida em duas porcentagens. Foram observadas que para baixas rotações a análise de partículas foi vantajosa em relação à análise de vibrações e que a contaminação por água, embora tenha ocasionado uma maior oxidação do sistema, proporcionou menor desgaste do que o lubrificante sem contaminação.
Every system or mechanical equipment is subject to deterioration processes. This deterioration takes to the apparition of defects that can disturb the continuity and quality of the service (production). One break not foreseen translates for an abrupt stop, usually taking to great damages and waste of time of production. For avoid unexpected stops efficiently and reduce the cost, predictive maintenance techniques are used. Among all the existent techniques, the most important in the maintenance of reducers are vibration analysis and wear particle analysis. The determination of the severity, wear modes and types in machines can be done through the identification of the morphology, surface finishing, coloration, nature, quantity and size of the particles found in oil samples or lubricating greases. Vibration Analysis is one of the oldest techniques in the maintenance. By vibration sign analysis it is possible to make decisions of intervening or not in the machine operation, improving its availability and reliability. The integration of these techniques has the potential to revolutionize industry practices and provide a significant industrial economic relief. For the study of these two techniques, in this work, an experimental bench was built with the purpose of doing the predictive maintenance in a reducer. The System was put to work until the limit. It was observed that for low rotations the wear particle analysis were advantageous in relation to the vibration analysis and for oil with water contamination, although causing a larger oxidation in the system, a smaller wear than the lubricant without contamination was provided.
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Lagresle, Charly. "Analyse du processus d’usure abrasive et optimisation d’engrenage aéronautique." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI113.
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Les organes de transmission de puissance par engrenages sont couramment utilisés dans de nombreux domaines, parmi lesquels celui de l'aéronautique. Le système étudié dans ces travaux de thèse est un réducteur d'hélicoptère. Son rôle est de transmettre la puissance générée par le turbomoteur à la boîte de transmission principale, tout en adaptant la vitesse de rotation au besoin de cette dernière. Pour maximiser la puissance massique des systèmes, les engrenages aéronautiques peuvent être dotés de voiles minces, réduisant la masse de l'ensemble, mais favorisant aussi leurs flexibilités. Très sollicités en termes de nombre de rotations et de conditions de fonctionnement, ces engrenages à voile mince du réducteur présentent un risque d’apparition de surpressions locales et sont d'autant plus susceptibles d’être soumis à un certain nombre d'avaries, telles que l'usure abrasive, le grippage ou encore le micro-écaillage. Le premier objectif de ces travaux de thèse est la compréhension et la simulation du processus d'usure abrasive sur les engrenages. Ce processus d'arrachement de matière sur le flanc des dentures est simulé par l'intermédiaire de la loi d'Archard adaptée aux contacts lubrifiés. Lors des différentes phases de vol (décollage, atterrissage, etc.), les conditions de fonctionnement évoluent et modifient les paramètres quasi-statiques de l’engrènement, la lubrification du système et par conséquent la quantité de matière arrachée. Afin de prendre en considération les évolutions des conditions de fonctionnement dans le processus d'usure, une méthodologie de cumul de l'usure a été adoptée et adaptée aux besoins de la simulation. Il est alors possible d'étudier la cinétique et l'intensité de l'usure sur les différentes phases de vol afin d'en déterminer les plus sévères. Le second objectif fait écho au premier. Après avoir cerné la problématique de l'usure, l'optimisation des paramètres quasi-statiques de l'engrenage à voile mince est mise en place. Cette optimisation, basée sur la recherche d'une micro-géométrie idéale, a pour vocation de réduire les causes potentielles de ces avaries, notamment les surpressions de contact ou le facteur de grippage d'Almen. Le problème étant qualifié de complexe, un algorithme MO-TRIBES d'optimisation multivariables et multicritères est déployé. De nombreux exemples d'optimisation sont proposés afin d'améliorer le comportement de cet engrenage à voile mince : réduction des fluctuations des signaux d'erreur de transmission sous-charge, des pressions maximales de contact, des facteurs de grippage, en simple et en multi-objectifs. Le choix des corrections de denture et de leur forme est aussi abordé. Finalement, grâce à ce module d'optimisation, il est possible de réduire l'arrachement de matière afin d'allonger la durée de vie de l'engrenagePowers transmissions are commonly used in many areas, including aeronautics. The studied system in this thesis is a helicopter gearbox. Its purpose is to transmit the power generated by the turbine engine to the main gearbox and to adapt the rotational speed of the input shaft. Aeronautical gears are light weight in order to maximize the power to weight ratio of the system. With thin rims, the mass of the system is reduced but its flexibility is increased. These types of gears, subjected to large number of revolutions and severe operating conditions, are more likely to be exposed to failures such as abrasive wear, scoring or micro-pitting. The first objective of this PhD thesis is the understanding and the simulation of the abrasive wear process for spur and helical gears. The material removal calculation is based on the well-known Archard equation, adapted to lubricated contacts. During the different phases of flight (take-off, landing, hover flight), the specific working conditions change. Consequently, the quasi-static gearing behaviour, the lubrication and therefore the quantity of wear need to be adapted. To this end, a new methodology is proposed to accumulate wear depths over several and different working conditions. This methodology makes it possible to analyze the kinetics and the intensity of the abrasive wear process and deduce the most severe phases of flight. The second goal echoes the first one. Following the identification of the problem of abrasive wear, a multi-objective optimization of the quasi-static behaviour of the thin rimmed gear is proposed. The goal of this optimization, based on the search of optimal tooth modifications, is to reduce potential sources of gear failures, in particular localized overpressures on tooth flanks or the Almen factor governing scuffing. Due to the complexity of the problem, a meta-heuristic multi-variable optimization algorithm (MO-TRIBES) is introduced. Multiple mono- and multi-objective gear optimization examples are provided in order to improve the quasi-static behaviour of the aeronautical gear : minimization of fluctuations of the transmission error under load, reduction of the maximal contact pressures, decrease of the scuffing risk factors. The ideal type of tooth modifications is discussed. Finally, by using the optimization module, the amount of wear is significantly reduced and a comfortable lifetime extension for the studied gear is provided
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Lago, Daniel Fabiano. "Manutenção de redutores de velocidade pela integração das técnicas preditivas de análise de vibrações e análise de óleo lubrificante /." Ilha Solteira : [s.n.], 2007. http://hdl.handle.net/11449/94548.
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Orientador: Aparecido Carlos GonçalvesBanca: Gilberto Pechoto de Melo
Banca: Jorge Nei Brito
Resumo: Todo sistema ou equipamento mecânico está sujeito a processos de deterioração. Esta deterioração leva ao aparecimento de defeitos que podem atrapalhar a continuidade e qualidade do serviço (produção). Uma quebra não prevista traduz-se por uma parada brusca, levando geralmente a grandes prejuízos e a perda de tempo de produção. Para evitar paradas inesperadas eficientemente e reduzir os custo de manutenção são utilizadas técnicas de manutenção preditiva. Entre todas as técnicas existentes, as mais importantes na manutenção de redutores são a análise de vibrações e a análise de partículas de desgaste. A determinação da severidade, modos e tipos de desgaste em máquinas pode ser feita pela identificação da morfologia, acabamento superficial, coloração, natureza, quantidade e tamanho das partículas encontradas em amostras de óleo ou graxas. Pela análise do sinal vibratório é possível tomar decisões de intervir ou não na operação da máquina, aumentando a disponibilidade e confiabilidade da mesma. A integração destas técnicas tem o potencial para revolucionar práticas industriais e proporcionar para as companhias um significante alívio econômico. Para estudo destas duas técnicas, neste trabalho foi construída uma bancada experimental com o propósito de se realizar a manutenção preditiva em um redutor de velocidades. O Sistema foi posto para funcionar até o limite de utilização. Foram utilizados lubrificantes recomendados pelo fabricante do redutor, lubrificantes com contaminação líquida em várias porcentagens e lubrificantes com contaminação sólida em duas porcentagens. Foram observadas que para baixas rotações a análise de partículas foi vantajosa em relação à análise de vibrações e que a contaminação por água, embora tenha ocasionado uma maior oxidação do sistema, proporcionou menor desgaste do que o lubrificante sem contaminação.
Abstract: Every system or mechanical equipment is subject to deterioration processes. This deterioration takes to the apparition of defects that can disturb the continuity and quality of the service (production). One break not foreseen translates for an abrupt stop, usually taking to great damages and waste of time of production. For avoid unexpected stops efficiently and reduce the cost, predictive maintenance techniques are used. Among all the existent techniques, the most important in the maintenance of reducers are vibration analysis and wear particle analysis. The determination of the severity, wear modes and types in machines can be done through the identification of the morphology, surface finishing, coloration, nature, quantity and size of the particles found in oil samples or lubricating greases. Vibration Analysis is one of the oldest techniques in the maintenance. By vibration sign analysis it is possible to make decisions of intervening or not in the machine operation, improving its availability and reliability. The integration of these techniques has the potential to revolutionize industry practices and provide a significant industrial economic relief. For the study of these two techniques, in this work, an experimental bench was built with the purpose of doing the predictive maintenance in a reducer. The System was put to work until the limit. It was observed that for low rotations the wear particle analysis were advantageous in relation to the vibration analysis and for oil with water contamination, although causing a larger oxidation in the system, a smaller wear than the lubricant without contamination was provided.
Mestre
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Flodin, Anders. "Wear of spur and helical gears." Doctoral thesis, KTH, Machine Design, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2986.
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Hu, Zedong. "An investigation into the wear and thermal-mechanical performance of polyacetal gears." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/99346/.
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Numerous concepts, national and commercial design standards developed and proved for metallic gears, now are being migrated over to polymer gears. However, it is uncertain whether the same procedures should apply and there is only limited data available to attempt a validation. Since wide mechanical and thermal properties’ discrepancies exist between metals and polymers, it is essential to develop and establish their individual investigation methods and science of design. The work presented in this thesis endeavours to bridge this gap between practical application and theory, through exploring advances in fundamental experimental investigation approaches and providing effective test data. New studies on wear and failure mechanisms, in addition to adopting the prevailing methods (i.e. SEM examining worn tooth surfaces), and inspecting wear debris are proposed and employed. Schemes are proposed for measuring the temperatures and velocities in the airflow surrounding the operating gears and gear bulk temperatures. Their use adds to the work for predicting surface temperatures of polymer gears. Deliberate misalignment is introduced to investigate. Wear and failure mechanisms of polyacetal gears at various loads and a speed of 1000 rpm are studied. Various regimes of wear debris and topographies of worn tooth surfaces are presented. The dynamic evolutions of wear, wear rate and the temperatures of airflow and the tooth body (bulk) are presented. It is found that transition temperatures are more reliable for assessing the gear wear compared to transition torques. Gross misalignment effects on the performance of polyacetal gears are investigated. Strikingly distinct topographies of worn tooth surfaces and regimes of wear debris are presented. It is indicated that polyacetal gears are most sensitive to pitch misalignment. Micro-cracks are noted near pitch points and tooth roots. Aerodynamic characteristics of operating gears are studied and an improved model is proposed. On the basis of it, methods for improving the durability of polyacetal gears are proposed. Further investigations on aerodynamics, thermal-mechanism and misalignment are recommended to gain a better temperature and wear prediction, and understanding of misalignment.
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Janakiraman, Venkatakrishna. "An Investigation of the Impact of Contact Parameters on the Wear Coefficient." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366906387.
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Natter, Bernard. "Etude de l'usure et de l'ecaillage de pieces d'un reacteur d'avion par la technique d'activation en couches superficielles." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13223.
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Utilisation de la technique d'activation en couches superficielles. Formation du radioelement cobalt 56 par reaction nucleaire. Etude du profil de concentration et mesure in situ d'usure et d'ecaillage (cas des pompes a carburant). Aspects metallurgiques. Application a l'industrie aeronautique
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Farré, Lladós Josep. "Novel lubrication system to improve the excessive wear in wind turbine yaw and pitch gears." Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/401832.
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Manufacturers of wind turbines have observed a new phenomenon that appears in high power wind turbines: excessive wear in the teeth located at 0º in the pitch bearing.
In order to design more efficient wind turbines, manufacturers are increasing the rotor diameter to capture more kinetic energy from the wind to generate more energy, therefore the stress in the joints/unions is increased, which leads to the elastic deformation of the system. These stresses and deformations increase in all parts of the wind turbine, the foundations and the tower, yaw, nacelle, drive train and blade unions. All these cases are mainly static unions, except the drive train that transmits torque, the yaw system that turns the nacelle and the pitch system that turns each blade around its axis.
The weight of the blades under movement, always working in the most efficient position, causes micro-movements allowed by the elastic deformations and the backlash of the gear transmission that induce an excessive wear at the zero degree position. The same phenomenon is observed in the yaw system, though to a lesser extent. Despite the manufacturer's efforts, a solution that could be implemented in the near future or easily retrofitted in the wind turbines does not yet exist.
The aim of this PhD project is to improve the lubrication of the pitch and yaw gear systems of wind turbines through the use of a novel lubrication system based on an array of micro-fabricated channels fitted at the gears' root (dedendum). A micro-nozzle to continuously inject fresh grease in between the teeth in contact has been designed, manufactured and installed in a test bench of a 2 MW wind turbine pitch system. The test bench has been used to characterize the fatigue behavior of the gear surface using conventional wind turbine greases under real cyclic loads, showing a delay of 2x10^4 cycles in the appearance of wear.
The proposed micro-nozzle is expected to be compatible with and easily implemented into both newly designed and in-market models. This novel lubrication system will inject fresh lubricant to the gear contact area even when the wind turbine is generating electricity.
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Sosa, Mario. "Running-in of gears from a surfacetransformation and efficiency point of view." Licentiate thesis, KTH, Tribologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173828.
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Requirements today for machines have moved beyond functionality intoefficiency and reliability, gears are no exception. The presented work focuseson the analysis of the measurement, evolution and effect of running-in on geardrives from a surface roughness and efficiency point of view. With no consen-sus on a definition or observation of running-in of gear drives, measurementsof both efficiency and surface transformation during the predefined running-inis explored. A verified methodology on how to separate form, waviness androughness is presented. Two finishing methods, namely generation groundand superfinished, are analyzed in terms of efficiency and surface characteris-tics as manufactured, after running-in and after efficiency testing in order todetermine the effects of load level during running-in.Results show that separation of form can be achieved with a carefullychosen polynomial, while waviness is more subject to how the user definesa cut-off wavelength for the surface roughness. Ground gears show distinctsmoothening in terms of surface roughness at high running-in load, and nogeneral trend for low load. This behavior is also reflected in the efficiencysince higher loads gave overall lower efficiency after running-in when com-pared to lower loads. Superfinished gears in contrast show no running-in ef-fects in terms of efficiency. Additionally, ground gears exhibit general changein friction and surface roughness during the first cycles of running-in whenanalyzing high load. Overall gains in efficiency can be obtained from running-in; however, at most speeds improvements from polishing a surface, in thiscase superfinishing, proved to lead to higher efficiency.QC 20150922
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Andersson, Martin. "Churning losses and efficiency in gearboxes." Licentiate thesis, KTH, Tribologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-152914.
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Efficient transmissions systems are key to producing competitive motor vehicles that have a smaller environmental impact. Gears are the main components in vehicle transmissions and although they are already highly efficient, there is still room for improvement. In this study, the focus falls on the lubricant used to create separating films between gears and todissipate heat. When driving, the gears churn this lubricant, giving rise to power losses that are related to the amount and properties of the lubricant. However, any attempt to reduce these losses must not compromise the required lubrication and heat dissipation. Paper A reports on the use of an FZG gear test rig to investigate power losses and heat generation for different gear immersion depths, surface roughness and coatings. The results show that lower gear roughness reduces gear mesh losses and heat generation. A polishing affect was obtained when a non-coated gear ran against a coated gear.The aim of the research reported in paper B was to increase the accuracy of efficiency testing. It investigated how and whether repeated disassembly and re-assembly of the same test equipment, as well as test performance and rig conditions, affect the measured torque loss in an FZG gear test rig. It was shown that the measured torque loss changes between one assembly and another. Repeatability between tests is crucial for accurate conclusions.The aim of the research reported in paper C was to study whether gear efficiency could be increased by a running-in procedure, which would reduce the need for a coolant. A back-to-back gear test rig was used to test two running-in loads. Higher gear mesh efficiency was seen when a higher running-in load was used.QC 20141006
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Jbily, Dalia. "Prise en compte de l’usure dans la modélisation du comportement sous charge des engrenages roues et vis tangentes." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI037/document.
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Les engrenages roues et vis sans fin sont une solution avantageuse pour transmettre le couple entre des axes perpendiculaires non concourants. Ces engrenages offrent une solution simple et efficace en terme de coût dans les applications de transmission de puissance, où un grand rapport de réduction est nécessaire, en comparaison avec les engrenages classiques à axes parallèles qui nécessitent normalement deux ou trois étapes pour obtenir les mêmes réductions avec une augmentation conséquente de complexité et du nombre de pièces. L’usure de surface est un des modes de défaillance observés dans la vie des engrenages roues et vis sans fin qui influe sur la portée de contact, les caractéristiques de transmission et le bruit résultant. La première étape de ces travaux est la mise au point d’un modèle numérique pour étudier le comportement quasi statique des engrenages roues et vis sans fin avec une roue en bronze et une vis en acier. Le modèle est basé sur la résolution des équations de compatibilité des déplacements ainsi que sur la méthode des coefficients d’influence. Les effets globaux de flexion et les effets locaux de contact ont été séparés. Les effets de contact ont été obtenus par la théorie de Boussinesq. Les coefficients de flexion sont estimés par la combinaison d’un calcul Éléments Finis et des fonctions d’interpolation, permettant d’une part de prendre en compte l’environnement de l'engrenage (la géométrie des arbres, des jantes et des voiles, l’emplacement des roulements,...) et d’autre part de réduire significativement les temps de calculs. Dans une seconde étape, une méthodologie est proposée pour modéliser l’usure de la surface de dent de la roue. Le modèle de contact quasi-statique de la répartition des charges est combiné avec un modèle d’usure d’Archard. Ce modèle suppose que la profondeur d’usure est directement proportionnelle à la pression de contact et à la distance de glissement et inversement proportionnelle à la dureté du matériau. Cette loi d’usure est modifiée pour prendre en compte l’influence des conditions de lubrification en utilisant un coefficient d’usure local, dépendant de l’épaisseur du film lubrifiant, rapportée à l’amplitude des rugosités des surfaces. L’enlèvement de matière par l’usure du flanc de la roue influe sur la répartition des pressions et donc les modifications de la géométrie des dents doivent être incluses dans la prédiction de l’usure. Le calcul des pressions de contact est ainsi mis à jour pour tenir compte des changements de géométrie. Enfin, pour valider le modèle développé des comparaisons du modèle avec des résultats expérimentaux issus de la bibliographie ont été effectuéesWorm gears are one of the technical devices for transmitting torque between spatial crossed axes. They provide a simple and cost effective solution in power transmission applications, where a high reduction ratio is required. Comparable conventional parallel axis gearing would normally require two or three stages to achieve the same reduction, with a consequent increase in complexity and number of parts. Surface wear is one of the failure modes observed in life worm gear sets which affects the contact patterns, the other transmission characteristics and the resultant noise. The first step of this work is the development of a numerical model to study provide the quasi-static behavior of worm gears with bronze wheel and steel worm. The model is based on solving of the equation of displacement compatibility and the influence coefficient method. The global effects of bending and local effects of contact are separated. The contact effects are obtained with the theory of Boussinesq. Bending effects are estimated by the combination of one standard FEM computation and interpolation functions. These methods allow, on the one hand, to take into account the environment of the gear (shaft shape, rim, web, bearing location ...) and on the other to reduce significantly the computation time. In a second step, a methodology is proposed for predicting the wear of the wheel tooth surface. In this process, a quasi-static contact model of the load distribution is combined with Archard's wear model. This model assumes that the wear depth is directly proportional to the contact pressure and sliding distance and inversely proportional to the hardness of the material. The wear law is modified to take into account the influence of the lubrication conditions using a local wear coefficient, depending on the lubricant film thickness, relative to the amplitude of surface roughness. Removal of material by wear on the wheel flank affects the pressure distribution, therefore the changes in teeth must be included in the prediction of wear. The calculation of contact pressures must also be updated to take into account the modification of the gear flank geometry. The last step concerns the validation of the numerical. Comparisons have been carried out between the model results and experimental ones issued from the bibliography
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Cerqueira, Pedro Aires da Cunha. "Mild wear in lubricated gear transmissions." Dissertação, 2015. https://repositorio-aberto.up.pt/handle/10216/79528.
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Cerqueira, Pedro Aires da Cunha. "Mild wear in lubricated gear transmissions." Master's thesis, 2015. https://repositorio-aberto.up.pt/handle/10216/79528.
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Hammami, Maroua. "Efficiency and wear in automotive gear transmissions." Tese, 2017. https://repositorio-aberto.up.pt/handle/10216/111956.
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"Aspects of wear in a gear system." Thesis, 2012. http://hdl.handle.net/10210/5464.
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M.Ing.The study was initiated by the inquiry from an oil company to scientifically determine the wear rate of the draglines gears. The main aim of the study was to establish an applicable practical means of measuring the amount of wear on gear tooth surfaces and to eventually integrate this metrology approach with finite element methodology for use in a maintenance strategy. Various methods found in the literature were reviewed. Due to the fact that the gears would only be available for periods when the draglines are serviced, the mould between two of the gear teeth seemed to be an appropriate suggestion. The mould would form the inverse of the gear tooth profile and be used for experimental tests. As certain detail was seen as confidential regarding the draglines, the study had to be done on a more available gear. A manageable size gear was donated for research by Reumech-Gear Ratio. The gear tooth profile as well as the mould were measured using a height gauge, and a gear-tooth calliper. The profile was also scanned by means of a digital scanner with a stylus gradually moving over the gear, and shown on a computer screen. The theoretical involute gear profile was generated and used as a reference to which the measured results could be compared by superimposing the profiles onto the reference gear profile. By comparing the measured results with the theoretical profile, it could be seen that both manual and automated results were within acceptable tolerance. Accuracy versus cost by comparison, therefore, would be the deciding factor. Further, the contact between two mating gear teeth was simulated using the finite element method. Gap elements were used to connect the nodes moving to one another. The finite element methodology could be used as a helpful maintenance instrument to link the measured gear wear to the equivalent stress levels during the different operational phases of the gear system. This could be a valuable means to manage gear life.
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Hammami, Maroua. "Efficiency and wear in automotive gear transmissions." Doctoral thesis, 2017. https://repositorio-aberto.up.pt/handle/10216/111956.
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Brandão, José Augusto de Sousa Ferreira. "Gear tooth flank damage prediction using high-cycle fatigue and wear models." Tese, 2013. https://repositorio-aberto.up.pt/handle/10216/75489.
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Brandão, José Augusto de Sousa Ferreira. "Gear tooth flank damage prediction using high-cycle fatigue and wear models." Doctoral thesis, 2013. https://repositorio-aberto.up.pt/handle/10216/75489.
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Ribas, Carlos José Gonçalves. "Influence of geometry, surface roughness, operating conditions on mild wear in lubricated gear transmissions." Dissertação, 2016. https://repositorio-aberto.up.pt/handle/10216/86182.
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Ribas, Carlos José Gonçalves. "Influence of geometry, surface roughness, operating conditions on mild wear in lubricated gear transmissions." Master's thesis, 2016. https://hdl.handle.net/10216/86182.
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Lin, Ah-Der, and 林阿德. "The Interaction between the Tooth Wear and the Dynamic Loads in a Spur Gear Pair." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/84649464342881135785.
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博士國立中山大學
機械工程學系研究所
89
Abstract The interaction among the tooth wear, dynamic loads, and its corresponding frequency spectrum variation in a spur gear pair is investigated in the dissertation. A mathematical model for the dynamic responses of a profile shifting involute gear pair is derived. For simplicity, a two-step mesh stiffness model is proposed to approximate the load sharing and the time-varying stiffness effects in a mating gear pair. The analytic solutions for the dynamic responses of this simplified dynamic model are derived in both time and frequency domains. The effect of the tooth wear on the spectrum variation has been illustrated analytically. The amplitude and frequency modulations introduced from the periodic load fluctuation have also been discussed. In order to characterize the time-varying mesh stiffness, frictional coefficient, damping ratio, temperature rise and load sharing effects between engaged teeth, a computational algorithm with the quasi-linear iteration procedure is developed to include above instantaneous parameters in the teeth engagement process. The tooth wear equation proposed by Flodin and Andersson (1997) is employed to simulate the mild wear process for an engaging gear pairs. The interactions between the tooth wear and the dynamic loads for the Steel/Steel, POM/POM, Nylon/Nylon and Steel/Nylon gears pair have been studied numerically. Numerical examples indicate that the proposed models are valid for gear pairs with different materials.
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Marinho, Albano Manuel Gonçalves. "Wear and friction torque in thrust ball and roller bearings lubricated with "windmill gear oils"." Dissertação, 2011. http://hdl.handle.net/10216/61346.
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Marinho, Albano Manuel Gonçalves. "Wear and friction torque in thrust ball and roller bearings lubricated with "windmill gear oils"." Master's thesis, 2011. http://hdl.handle.net/10216/61346.
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Tai, Sheng, and 吳聖泰. "Developing a novel four-ball wear tester and its application to study the relationship between viscosity and antiwear ability for gear oils." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/73815651381924421745.
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碩士國立雲林科技大學
機械工程系碩士班
101
In the four-ball test, an optical microscopy is used to gauge the diameters of the wear spots on the three SUJ2 balls, and the friction coefficient is determined by the torque measurement; as for the linear reciprocal tests, two groups of materials are adopted: SUJ2 ball vs. S45C plate and SUS304 ball vs TiCN coating. In the former test, the degree of wear is evaluated by the sectional area of the scratched profile, detected by the white-light interference meter; while for the later, the ability of the level of wear is represented by the weight loss of the SUS304 ball, measured by a precision electronic scale. The experimental results imply: the wear diameter in the four-ball test is clear due to the fact that the debris can be easily washed away since all balls are immersed in the lubricant and the upper ball keeps rotating in the same direction. Averaging three spot diameters on three balls for each test yields very stable test results. The friction is the summation of the shear stress from liquid viscosity and the adhesion on the solid contacting points. The case of medium viscosity oil produces the highest friction. As for the reciprocal test of SUJ2/S45C, the friction coefficient varies monotonically in a relatively narrow range, since in this case the sliding resistance from the adhesion on the solid/solid interface is much less than that from the plastic deformation of plowing. Calculating the area of the plowed section is generally affected by the following factors: the inadequate choice of the base line of calculation, the variations of the scratch profile owning to the inconstant moving speed of the plate, and the refilling and smashing of the loose wear particles. All these may reveal a wrong image of the material anti-wear ability. On the other hand, the friction coefficient of the SUS304/TiCN test shows a monotonic while wider distribution. The wear type is purely adhesive, which can generate stable weight losses having a good correlation with friction.
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CHEN, YI-MING, and 陳怡銘. "Research and Test on Wear of Spur Gears and Helical Gears." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/994jh6.
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碩士龍華科技大學
機械工程系碩士班
106
This paper is mainly to study and test wear and accuracy of gear tooth surface of spur gear group and helical gear group after generation of operational wear. The wear of gears usually occurs under long operating time and high load. In this study, two planetary reducers of experiment groups A and B and two planetary reducers of control groups C and D were used to carry out comparison. Under the circumstances of same frame diameter and same specific speed, this study designed and manufactured the spur gear planetary reducers and helical gear planetary reducers separately, and confined axial movement space of the three planetary gears inside the reducers in order to reduce the factors of effect such as axial thrust when helical gear is running. Operating under same material, same modulus, same gear accuracy level, using same lubricating grease, same heat treatment and same rated load, and through same test conditions and method, this study examined and observed the relative wears of spur gear and helical gear and made comparisons, and improved shortcomings of experimental groups through changing gear crowning design. Through researching and understanding that helical gear would generate axial thrust in a confined space, and its gear engaging contact line of helical gear is longer than that of spur gear, this study investigated whether wear speed of helical gear is the same as that of spur gear. Through analyzing the experimental data obtained from 18 million revolutions of actual test, it is confirmed that under the circumstances of confined space and generating axial thrust, the average wear rate of tooth surface of helical gear groups is not faster than that of spur gear groups. However, the positioning error accuracy of helical gear groups changed 9.88 arc minutes from 1.46 arc minutes before operation to 11.34 arc minutes after load operation. Although it could be slightly retarded through changing tooth profile of experiment groups after trimming 0.01mm of design, there is still an obvious gap compared to the change of approximately 2 arc minutes of positioning accuracy of spur gear before and after operation.
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Кучин, С. Г., and S. G. Kuchin. "Повышение точности формообразующих перемещений при высокоскоростном точении : магистерская диссертация." Master's thesis, 2016. http://hdl.handle.net/10995/41093.
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Цель работы – разработка новых технических средств повышения точности формообразующих перемещении металлорежущих станков при высокоскоростном точении.
Проведен анализ погрешностей влияющих на точность формообразующих перемещений станка при высокоскоростном точении, анализ существующих способов компенсации погрешностей. На его основе разработаны устройство согласования формообразующих перемещений рабочих органов станков, устройство для компенсации износа направляющих и инструмента металлорежущего станка, устройство компенсации износа элементов металлорежущего станка. Данные устройства точнее существующих.
В ходе работы над магистерской диссертацией, был получен Патент РФ № 160852 «Устройство согласования формообразующих перемещений рабочих органов станков», приоритетная справка № 022052 по заявке на патент № 2016114038 «Устройство компенсации износа элементов металлорежущего станка». Принято участие во Всероссийской молодежной научно-практической конференции «Региональные программы и проекты в области интеллектуальной собственности глазами молодежи» в рамках IX Международного форума «Интеллектуальная собственность – XXI век», по результатам которой получен диплом проекта. Тезисы проекта опубликованы в каталоге проектов участников конференции.The purpose of the work is the development of new technical ways to improve the accuracy of form-building movements of machine tools in high-speed turning. The analysis of errors of form-building movements of machine influencing accuracy in high-speed turning, existing ways of errors compensation was carried out. The analysis was used in order to design device of coordination of form-building movements of machines working units, device of compensation of wear of guideways and tools of machine tool, device of compensation of wear of elements of machine tool. Developed solutions give more accurate results. During the work on the master's thesis author received patent of RF № 160852 «Device of coordination of form-building movements of machines working units» and priority reference № 022052 according to patent application № 2016114038 «Device of compensation of wear of elements of machine tool». The work participated in the All-Russian youth scientific conference "Regional programs and projects in the field of intellectual property through the eyes of young people" within The International forum «Intellectual property – 21st century», by results of which diploma of the project is gained. Abstracts of the project are published in the conference digest.
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Cariaga, Joselito D. "A predictive procedure for wear, pitting, and scoring of gears based on combined thermal and mechanical stresses." 1997. http://catalog.hathitrust.org/api/volumes/oclc/39286962.html.
Full textAbstract:
Thesis (Ph. D.)--University of Wisconsin--Madison, 1997.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 325-336).