Recently, many industries pursue the goal of automatic high-speed assembly and manufacturing. So how to meet the requirement of high-precision and high-speed automatic assembly equipment is an important issue. In automatic assembly equipment, the high-speed indexing devices have been widely used because of their features of high precision, no backlash, and compactness. With increasing operating speeds, the problems of shortage of motor power, poor indexing accuracy, vibration, and noise shall be solved. The torque compensation mechanism that is to be developed here is applied to keep motors operating at constant speeds by compensating the required torque. In previous researches, the researchers all devote to study torque compensation based on synchronous time chart. In this paper, it is aimed at compensation of the time control chart according the point of view of energy and the system model is built to simulate dynamic response of the system. Through the results of simulation and experiment, we will discover the relations between the compensation time chart and parameters about the high-speed indexing devices. It is expected to improve the precision of indexing devices according to those effective compensation time control charts.

ABSTRACT Presently, many industrial applications of gear sets with skew axes, especially worm gear and hypoid gear, are most widely used. The main content of this thesis is to construct the contact analysis model of the line-contacted type tooth profile of gear sets with skew axes with assembly error. The influence of geometrical parameters of skew-axes gear to the transmission error is analyzed. The complex method for optimization is implemented to select the better skew-axes gear parameters with the best performance in transmission error with assembly error. To prove the presented analysis model, the optimized gear parameters are utilized to construct the solid model for analyzing the contact properties by using computer simulation program.

Planetary gear mechanisms are widely used in automobile automatic transmissions. However, the relevant design theories are not well development, especially the synthesis of the clutching sequence. Thus, the purpose of this study is to develop a systematical methodology for the design of automobile automatic transmissions. First, the specifications are established according to the characteristics of the automatic transmissions. Second, a procedure is created to list the speed ratio table and the clutching table for the planetary gear mechanisms. Third, based on the clutching table, a systematical method is developed to synthesize the clutching sequences. Then, the clutches and brakes are arranged into the planetary gear mechanisms to form the schematic of an automatic transmission. Finally, according to the relations between speed ratios and the numbers of teeth of gears, the gear-teeth synthesis is carried out when several certain speed ratios are assigned. A seven-link 2-DOF Ravigneaux gear mechanism, a eight-link 2-DOF Ravigneaux gear mechanism and a nine-link 2-DOF stepped Ravigneaux gear mechanism are as the design examples. And a four-speed, a six-speed and an eight-speed automatic transmissions are synthesized, respectively. The result of this study shows that the proposed methodology can be applied to design any 2-DOF planetary automatic transmissions.

<p>The demands the automotive gear designer has to considerduring the gear design process have changed. To design a gearthat will not fail is still a challenging task, but now lownoise is also a main objective. Both customers and legalregulations demand noise reduction of gears. Moreover, thequality of the product is more in focus than ever before. Inaddition, the gear design process itself must be inexpensiveand quick. One can say that the gear designer faces a newdesign environment. The objective of this thesis is tocontribute to the answer to some of the questions raised inthis new design environment.</p><p>In order to respond to the new design situation, the geardesigner must consider new phenomena of gears that werepreviously not a matter of concern. One such phenomenon is anew gear failure type, Tooth Interior Fatigue Fracture (TIFF).As the gear teeth are made more slender in an attempt to reducethe stiffness variation during the mesh cycle, therebypotentially reducing the noise, the risk of TIFF is increased.The phenomenon of TIFF is explored in detail (paper III-VI)through fractographic analysis, numerical crack initiationanalysis using FEM, determination of residual stress by meansof neutron diffraction measurements, testing for determiningmaterial fatigue properties, fracture mechanical FE-analysis,sensitivity analysis and the development of an engineeringdesign method. The main findings of the analysis of TIFF arethat TIFF cracks initiate in the tooth interior, TIFF occursmainly in case hardened idlers, the fracture surface has acharacteristic plateau at approximately the mid-height of thetooth and the risk of TIFF is more pronounced in slender gearteeth.</p><p>Along with the more optimised gear design, there is atendency for the gear to be less robust. Low robustness, i.e.,great variation in performance of the product, implies a highincidence of rejects, malfunction and/or bad-will, all of whichmay have a negative effect on company earnings. As the use ofoptimisation decreases the safety margins, greater attentionhas to be paid to guaranteeing the products' robustness.Moreover, in order to be cost-effective, the qualities of thegear must be verified early in the design process, implying anextended use of simulations. In this thesis, two robustnessanalyses are presented in which the analysing tool issimulation. The first one considers robust tooth root bendingfatigue strength as the gear is exposed to mounting errors, thesecond one considers robust noise characteristics of a gearexposed to manufacturing errors, varying torque and wear. Bothof these case studies address the problem of robustness ofgears and demonstrate how it can be estimated by use ofsimulations. The main result from the former robustnessanalysis is that wide gears are more sensitive to mountingerrors, while the latter analysis showed that to achieve robustnoise characteristics of a gear it should have large helixangles, and some profile- and lead crowning should beintroduced. The transverse contact ratio is a trade-off factorin the sense that both low average noise levels and low scatterin noise due to perturbations cannot be achieved.</p><p><b>Keywords</b>: robust design, Taguchi method, gear, idler,simulations, Finite Element Method, Tooth Interior FatigueFracture, TIFF</p>

The primary objective of this research is to develop a visual design process for gear trains with multiple stages of reduction and varying configurational architectures. One of the main challenges in the design of such gear trains is in the sizing of the individual gears such that high levels of performance are obtained in spite of constraints due to different gear configurations. Formal design procedures that successfully meet this challenge are developed. A key contribution of this research is the utilization of these design procedures to create sets of three-dimensional design maps. The design procedures help a designer manage more than 20 design parameters in designing for a broad range of gear train requirements (Rated torque capacity, Volume, Weight, Inertia, Responsiveness, Torque Density etc.) while accounting for assembly constraints. Each set of design maps corresponds to a given set of design parameters, some of which are held fixed and some of which are put in the hands of the designer. The latter set of design parameters are termed in this research as design knobs. They can be ‘tuned’ by a designer in order to generate new sets of design maps. The idea is that a designer, using the design information conveyed to him/her graphically through a given set of design maps, is able to then tune the design knobs to generate an updated set of design maps which reflect design solutions that are more desirable in terms of the application requirements. By adjusting the design knobs and looking at updated design maps, a designer is able to quickly assess the effect of his/her design decisions. The end result is that a single designer is empowered with the ability to quickly arrive at a preliminary design of a gear train that satisfies the design requirements. This preliminary design would be a good starting point for more detailed design development. / text

Aircraft control mechanisms, such as those that operate the flaps, ailerons, rudders, etc., are almost exclusively driven by hydraulic-based systems. Their popularity in flight control systems is not unfounded; hydraulic actuators are quite torque-dense and benefit from decades of development bringing operating performance to a high level. On the other hand the infrastructure to support this system increases weight, adds system development complexity, and reduces aircraft maintainability [Jensen et al, 2000]. Based on recent Electro-Mechanical Actuator (EMA) development and design efforts at the Robotics Research Group (RRG), a new opportunity exists to replace current hydraulic flight control systems with those powered by electricity through a national program [Tesar, 2005]. A literature review of the topic found a 30 year old effort by AiResearch to develop a similarly powered hingeline actuator with given traditional performance goals (torque capacity, redundancy, output speed, reliability). In this report,a thorough analysis is performed on each major component group to quantitatively evaluate this baseline device. Using component technologies developed at RRG, this report proposes a dual torque-summing electromechanical actuator, each with a star compound / hypocyclic combined gear train, designed to exceed the performance of the original (1976) AiResearch project. This preliminary design exercise includes a layout of the entire actuator along with an appropriate analysis of major components including bearings, gear train, motor, housing, and release mechanism. The performance of this gear train is critical to overall actuator success and fundamental analytics have already been developed in this area [Park and Tesar, 2005]. Finite Element Analysis on the gear train and housing provide early design feedback and verification of actuator performance characteristics. In particular, simulation results show the gear stiffness, load sharing, and torque capacities exceed analytical estimates. Finally, four different comparisons are presented that evaluate configuration variations of the two designs based on applicable performance criteria. Results show the RRG fault-tolerant actuator has a marked improvement over the baseline in average stiffness (14.2x), reflected inertia (3.2x) and nominal torque density (3.4x). The chapter next lists actuator test methods and aircraft qualification standards. Finally, a summary of future work is detailed in a ten step outline to bring this EMA technology to a level of early deployment in a large range of aircraft systems.

The purpose of this research was to identify the composition of soils on firefighter turnout gear from the Philadelphia Fire Department and to determine which soils contain hazardous materials. The objective of the research was to identify the composition of soils remaining on the firefighter turnout gear to enable the industry to design an effective cleaning procedure for removal of soils. A pilot study was conducted on hoods from the Philadelphia fire department to evaluate the test methods that would be used to identify the composition of soils. Soils that had been identified from previous studies were targeted in the analysis of the extraction of the samples removed from the hoods. Samples were removed from areas of the coats and pants where dermal absorption is reported as high areas of skin absorption, including areas in the neck, armpit, crotch and wrist locations.

Thesis(M.S.)--Auburn University, 2005. / Abstract. Includes bibliographic references.

Two students from the school of engineering in Jönköping has during the spring semester of 2018 performed a bachelor thesis. The thesis was performed in cooperation with Greenworks Tools in Jönköping. The purpose of this thesis is to establish an understanding of the technical aspects of a hedge trimmer and the product development process. During this thesis, the students will generate and evaluate different concepts for a new gearing system. The study investigates if it is possible to rotate the motor in one of Greenworks hedge trimmers 90±15°along the cutting direction, without deteriorating the hedge trimmer´s performance or ergonomical propperties. The main limitation for the thesis is that exclusively the motor gear and the connection to the gearbox can be changed. To answere the thesis problem different kinds of methods and tools were used. A few of the implemented methods used during the thesis are product development process, QFD and Pugh’s matrix, to verify the concepts Cad simulations and calculations were established. The result of the study shows that it is possible to rotate the motor without detoriating the hedge trimmers preformance with respect to the given information. The thesis study generates a basis for further development and for future products.

Um dos métodos de fabricação de engrenagem em grande escala é baseado na usinagem por ferramentas de corte denominadas Cortador Hob ou Fresa Caracol. Esse método permite agilidade e precisão. A máquina e a ferramenta destinadas a esse processo são para aplicação específica na fabricação de dentados em engrenagens e eixos, fazendo-se necessário portanto um aprofundamento na otimização, melhor utilização dessas ferramentas. A não substituição da ferramenta no momento correto implica em dois problemas: ou ela poder ser trocada antes do término da vida ou ela pode ser usada em excesso e formar o chamado desgaste excessivo, o que reduz o número de afiações do cortador. O ponto a ser estudado o qual se trata essa dissertação é poder estimar a quantidade de peças a ser produzida com cada uma dessas ferramentas. Entretanto, sabe-se que uma mesma ferramenta pode ser aplicada a diversos tipos de peças, com variação de diâmetro e espessura, o que caracteriza a complexibilidade desse processo. Para isso foram coletados dados de usinagem e de desgaste da ferramenta em função das dimensões do par peça/ferramenta. Depois foram determinada curva padrão de desgaste em relação ao par peça/ferramenta e a partir dessa curva padrão, determinar a vida dos cortadores em quantidade de peças a serem fabricadas. Em seguida, os testes realizados puderam comprovar a efetividade dessa correlação. / The method of manufacture of gear on a large scale is based on process that use cutting tools, called Hob or “Caracol”. This method allows the speed and accuracy. The machine and tool designed for this process are specific for application in the manufacture of toothed gears and shafts. This making it necessary insight into the optimization of these tools. Failure to replace the tool at the right time involves two problems: or it can be exchanged before the end of life, or it can be overused and form the so-called excessive wear, which reduces the number of cutter sharpenings. The point of study from which it comes this work is to determine the quantity of parts to be produced with each of these tools, it know that the same tool can be applied to various types of pieces, ranging in diameter and thickness, which characterizes the complexity of this process. Therefore data about machining tool wear depending on the size of the pair part / tool were plotted collected. After that, standard curves of wear in relation to the pair part / tool and by this standard curve, to determine the life of the cutters in quantities of parts to be manufactured. Soon after, the tests performed could proved the effectiveness of this correlation.