Orientador: José Maria Campos dos Santos / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica, Faculdade de Engenharia Eletrica e de Computação e Instituto de Química / Made available in DSpace on 2018-09-11T21:15:54Z (GMT). No. of bitstreams: 1 Pecula_MauroMiguel_M.pdf: 3399170 bytes, checksum: eb3730f4b592d4e1060f9a87cfd2bfe4 (MD5) Previous issue date: 2010 / Resumo: Os requisitos de qualidade sonora estão sendo cada vez mais utilizados no mercado de caminhões médios e pesados. Assim, proprietários de veículos sentem-se incomodados pelo ruído de engrenamento. O estudo do ruído de engrenamento neste trabalho baseia-se em um par engrenado de um motor diesel pesado de aplicação veicular. Como primeiro estudo foi calculado o erro de transmissão das engrenagens por meio das deformações dos dentes sob carga que conforme a literatura a sua amplitude de pico a pico está diretamente relacionada com o ruído de engrenamento. A verificação desta influência foi feita através de medições vibro - acústicas do motor em marcha lenta. Os dados calculados do erro de transmissão e dos sinais medidos foram confrontados obtendo-se convergência. Uma análise de qualidade sonora, por meio de teste de júri, foi realizada para verificar o impacto do ruído de engrenamento na qualidade sonora / Abstract: The requirements of sound quality are increasingly being used in medium and heavy trucks market. Then, owners of vehicles fell troubled by whine noise. The study of whine noise in this thesis is based in one geared pair of a heavy duty diesel engine for vehicular application. As a first approach the transmission error of the gears was calculated by the deformations of the teeth under load (compliance), according to literature, the transmission error peak to peak amplitude, had directly correlation with the whine noise. The proofing of this influence was performed through vibro-acoustics measurements of the engine in low idle. The calculated data of transmission error and processed measurements signals were confronted, obtaining convergence. A sound quality analysis, by juri test, was performed to verify the impact of the whine noise in sound quality / Mestrado / Dinâmica / Mestre em Engenharia Automobilistica

<p><p>In order to be competitive in the markets of today, more and more companies try to make their production more effective by automation. Consequently more money is invested in robots and the operability of the robots becomes increasingly important. Undetected faults may result in damages, both to the robot itself and to the operator, which make detection and prediction of faults important.</p><p>The gearboxes responsible for controlling the motions of the robots are essential for their functionality. In order to increase the understanding about them this project focuses on creating a model of the stress distribution inside a gearbox.</p><p>First, the geometry of the gearbox is measured and digitalized using a vernier caliper, a protractor, a ruler and the CAD-program Solid Works. Then the geometry is imported into the finite element program Samcef.</p><p>In Samcef, the interaction between the parts in the gearbox is modeled and a dynamic simulation of the stresses inside the gearbox during a robot cycle performed.</p><p>Since there are almost no experience about Samcef at ABB SECRC, part of the project is to evaluate the program and comment the experiences received when using it.</p><p>Two main power transmission steps are identified, modeled and simulated. They are merged together into a big model where both steps are present. This model consists of all the essential power transmission inside the gearbox, from input to output. The load applied is a rotational movement on the input axle during a robot cycle.</p></p>

Selection of steels for industrial purposes usually means choosing a type of steel to make a part or a product. The steel that is chosen must meet all the designer requirements. A quantitative selection procedure has been used to analyze the large amount of data involved in this selection process so that a complete and systematic evaluation can be made. The designer is responsible for the selection of steel, and this selection requires the designer to find data and information on the mechanical properties required, and also learns ways to improve these properties through different heat treatment processes. When a large number of steels and a large number of specified mechanical properties are being evaluated for selection, the weighed properties method can require a large number of tedious and time-consuming calculations. In such cases a computer program could greatly facilitate the selection process. This thesis reports the selection of steels for gears, shafts, fasteners and springs where the steps involved in the weighted properties method which is written in the form of a simple computer program to select steels from a data bank. This program also includes the digital logic method to help in determining weighing factors. The steels are ranked according to standard designation; BS, AISI, and DIN. It has been found that alloyed steels hardened and tempered at 2050C are most suitable for gears, shafts, fasteners, and springs when higher mechanical properties required, and carbon and low alloyed steels when cost is the main consideration.

In order to be competitive in the markets of today, more and more companies try to make their production more effective by automation. Consequently more money is invested in robots and the operability of the robots becomes increasingly important. Undetected faults may result in damages, both to the robot itself and to the operator, which make detection and prediction of faults important. The gearboxes responsible for controlling the motions of the robots are essential for their functionality. In order to increase the understanding about them this project focuses on creating a model of the stress distribution inside a gearbox. First, the geometry of the gearbox is measured and digitalized using a vernier caliper, a protractor, a ruler and the CAD-program Solid Works. Then the geometry is imported into the finite element program Samcef. In Samcef, the interaction between the parts in the gearbox is modeled and a dynamic simulation of the stresses inside the gearbox during a robot cycle performed. Since there are almost no experience about Samcef at ABB SECRC, part of the project is to evaluate the program and comment the experiences received when using it. Two main power transmission steps are identified, modeled and simulated. They are merged together into a big model where both steps are present. This model consists of all the essential power transmission inside the gearbox, from input to output. The load applied is a rotational movement on the input axle during a robot cycle.

In the field of electric machine design, a trend in many applications has been to design machines with increasing torque density. When machines fail to meet torque density requirements or are simply incapable of matching load torque, gears are commonly used. Magnetic gears have been proposed as a means of increasing torque density within electromechanical systems, while avoiding problems associated with traditional mechanical gears. While the idea behind magnetic gears goes back to early patents, their study and use in industry has been very limited to date. This study looks into variations of the gear which could lead to more industrial use. The effect of pole count upon torque ripple is investigated with finite element analysis (FEA). The analysis is extended to new magnetic layouts which borrow from permanent magnet machine design. One of the most critical components of the gear, the stator pole pieces, are also investigated for variations which aid in construction while maintaining the performance of the gear. As a means of supplementing analysis of the gear, winding function theory (WFT) is used to analyze the gear. Winding function theory has enjoyed success with induction, synchronous, and even switched reluctance machines in the past. This study is the first of its kind to apply winding function theory to a device devoid of windings altogether. It is shown that this method is capable of generating the stall torque and steady-state torque ripple waveforms which have been commonly attempted with FEA. While magnetic gears enjoy distinct advantages over mechanical gears such as inherent overload protection, they are not as torsionally stiff as their mechanical counterparts. As such, the use of damper windings for the purpose of stiffening the gear against transient oscillations is also investigated. Several competing designs are investigated for their performance, and a final design is studied which is capable of arresting transient oscillations in less than a second. In addition, a prototype has been fabricated and will be used to verify the analysis undertaken. The prototype is used to verify variations of the stator pole pieces as well as the inner rotor magnetic layout. A dynamometer has been assembled to test the performance of the prototype. A new design is also proposed for future work.

<p>The objective of this thesis is to find and develop methods that enhance and support the creation of evolvable master process plans with possibilities to challenge productivity and meet changing design requirements. The condition for achieving this is primarily that both the fundamental thinking and the results behind a process plan can be described. How should this be done?</p><p>The focus is laid on process planning of gear transmission parts for heavy vehicles like trucks and coaches.</p><p>Process planning is the activity where design and manufacturing are brought together with the common target to achieve both a competitive product and production process. There are many factors that influence the process planner when a new product or process shall be introduced for production. Process planning is, in most cases, performed by an experienced, skilled person but without any defined methodology or way of working. Much of the process planning is based on the retrieval of solutions already used.</p><p>Much research effort has been devoted to developing systems for computer-aided process planning (CAPP). Yet CAPP systems have not been accepted and spread over a wide front within the manufacturing industry, much because of the functional incompleteness combined with the difficulties of adopting knowledge and changing requests.</p><p>A method for systematic process planning is proposed as a way to perform and describe the procedure of creating a process plan. The method facilitates the interpretation and understanding of the plan, not only immediately for the process planner responsible, but also for designers, engineers, researchers and other interest groups involved in a manufacturing process.</p><p>In the last chapter is a case study regarding manufacturing of a bevel gear pinion presented to exemplify use of the proposed method for systematic process planning.</p> / KUGG

M. Ing. / Reliability is basically the measure of performance, it is the probability that a system or component will perform its required task without failure under certain conditions for a given period of time [1]. As systems have become more complex in recent time the need for reliability within that system has become more and more important, safety, productivity and profit are three factors that have also demanded an increased level of reliability [2]. The reliability of an industrial gear unit comes from the reliability of all the individual components within the gear unit. Bearing lives are often the limiting factor of a gear unit and more often than not the lubrication becomes contaminated through insufficient maintenance practices, operational practices and harsh environments. This then results in the premature bearing failures within the gear unit. If the gear unit’s “health” can be monitored and imminent failures are known then the unit can be taken out of service and replaced or repaired prior to failure and during scheduled maintenance periods, this will then reduce overall repair costs and drastically reduce unscheduled maintenance time and cost.

With ever shorter development times and market demands on overall system performance such as efficiency, reliability and low maintenance, accurate predictive tools are necessary and gear drives prove to be no exception. All these characteristics have an impact on a process which has remained a riddle: running-in. Even though no consensus on a definition of this phenomena is readily available, this thesis examines efficiency, surface roughness and simulation through the optics of running-in. Geared transmissions are known for their formidable efficiency and their extreme reliability. However, with an ever increasing power density, the ability to accurately predict mesh losses becomes of utmost importance. The accurate quantification of bearing losses as well as efficiency of ground and superfinished gears under dip lubrication are examined with respect to running-in. Results show a considerable influence on the calculation of gear mesh losses originating from which bearing loss model is chosen. Furthermore, when a larger running-in load is used on ground gears, an increase in efficiency can be observed during working operation, while for superfinished no significant changes are found. These efficiency/frictional changes are also shown to occur in the initial cycles of the running-in phase. From a surface transformation point of view running-in is shown to be a reduction of asperity tips in case hardened ground gears, while in superfinished gears no changes were seen. These gear surface changes were measured with a novel method with a surface profilometer in-situ before, after running-in and after efficiency testing. Results also show that such changes in ground gear roughness profile occur during the very initial cycles. In order to predict running-in, a simulation method was developed. Such method utilizes a 2D surface integral method to simulate contact between rough surfaces, but requires the use of surface hardness and an accurate lower cutoff wavelength. This cutoff wavelength proved to play a pivotal role in determining an accurate contact pressure at the proper level of granularity, hence a well defined real contact area. The predicted and measured run-in surfaces are compared and are found to be in accordance with each other. / <p>QC 20170928</p>

Torsional vibrations in differentials of Rear Wheel Drive vehicles are of major importance for the automotive industry. Hypoid transmissions, forming the motion transfer mechanism from the driveshaft to the wheels, suffer from severe vibration issues. The latter are attributed to improper mesh between the mating gear flanks due to misalignments, variation of contact load and shifting of the effective mesh position. For certain operating conditions, the gear pair exhibits high amplitude motions accompanied with separation of the mating surfaces. Ultimately, single or even double-sided vibro-impact phenomena evolve, which have been related to noise generation. This thesis attempts to address these issues by effectively analysing the dynamic behaviour of a hypoid gear pair under torsional motion. The case study considered is focused on a commercial light truck. The major difference of the employed mathematical model to prior formulations is the usage of an alternative expression for the dynamic transmission error so that the variation of contact radii and transmission error can be accounted for. This approach combined to a correlation of the resistive torque in terms of the angular velocity of the differential enables the achievement of steady state, stable periodic solutions. The dynamic complexity of systems with gears necessitates the identification of the various response regimes. A solution continuation method (software AUTO) is employed to determine the stable/unstable branches over the operating range of the differential. The ensuing parametric studies convey the importance of the main system parameters on the dynamic behaviour of the transmission yielding crucial design guidelines. A tribo-dynamic investigation aims at expanding the dynamic model from pure dry conditions to a more integrated elastohydrodynamic (EHL) approach. Analytical and extrapolated solutions are applied for the derivation of the film thickness magnitude based on the kinematic and loading characteristics of the dynamic model. The temperature rise is governed mainly by conduction due to the thin lubricant films. The generated friction is also computed as a function of the viscous shear and asperity interactions. The effective lubricant viscosity is greatly affected by the pressure increase due to the resonant behaviour of the contact load. The final part of this work is involved with a feasibility study concerning the application of Nonlinear Energy Sinks (NES) as vibration absorbers, exploiting their ability for broadband frequency interaction. Response regimes associated with effective energy absorption are identified and encouraging results are obtained, showing the potential of the method.

There are numerous benefits associated with replacing hydraulic actuators with electrical counterparts as part of an all electric landing gear including reduced consumption of non-propulsive engine power, reduced weight, reduced cost and the elimination of hydraulic systems. The development of health monitoring systems to support the introduction of electrical actuation systems into landing gears will aid in guaranteeing reliability and to optimise landing gear maintenance activities. One of the difficulties with designing health monitoring for industrial integration involves the large number of subject areas involved, ranging from architectural design, software and signal processing design, hardware selection and business modelling. The reason that many health monitoring systems never reach full development maturity is that there is a failure in realising a holistic design process. The purpose of this thesis and the overall contribution which has been made is to bring together a combined understanding of landing gear design, health monitoring and the business environment for aircraft maintenance in order for a holistic design process for landing gear health monitoring to be realised.