Optimum design of multistep gearbox, since many high-performance power transmission applications (e.g., automotive, space industry) require compact volume, has become an important interest area. This design application includes more complicated problems that are not taken into account while designing single stage gear drives. Design applications are generally made by trial and error methods depending on the experience and the intuition of the designer. In this study, using Visual Basic 6.0, an interactive program is developed for designing multistep involute standard and nonstandard spur gearbox according to the American Gear Manufacturers Association (AGMA) Standards 218.01 and 2001- B88. All the equations for calculating the pitting resistance geometry factor I, and the bending strength geometry factor J, are valid for external spur gears that are generated by rack-type tools (rack cutters or hobs). The program is made for twostage to six-stage gear drives, which are commonly used in the industry. Compactness of gear pairs and gearbox, and equality of factor of safety against bending failure is taken as the design objective. By considering the total required gear ratio, the number of reduction stages is input by the user. Gear ratios of every stage is distributed to the stages according to the total gear ratio that satisfies the required precision (from &plusmn / 0.1 to &plusmn / 0.00001 on overall gear ratio) depending on the user selected constraints (unequal gear ratio for every stage, noninteger gear ratio e.g.). Dimensional design is determined by considering bending stress, pitting stress, and involute interference constraints. These steps are carried out iteratively until a desirable solution is acquired. The necessary parameters for configuration design such as number of teeth, module, addendum modification coefficient, are selected from previously determined gear pairs that satisfies the constraints by user interaction considering the performance criterion from the developed program. The positions of gears and shafts are determined automatically in order to keep the volume of gearbox as minimum while satisfying the nonlinear spatial constraints (center distance constraint for proper meshing of gear pairs, face distance constraint for proper assembly of pinion and gear having same shaft, gear interference constraint for preventing interferences between gears, shaft interference constraint for preventing interferences between gears and shafts) by using DLL (Dynamic Link Library) technology of Lingo 8.0 optimization software together with Visual Basic 6.0. If shaft interference constraint is removed then cantilevered mounting of gear pairs would also be possible, otherwise the gears should be mounted between bearings. Visual output of assembly is made by using Autodesk Inventor 7.0, automatically by the program.

O presente trabalho foi desenvolvido com o intuito de propor um sistema de transmissão mecânica baseado em engrenagens cônicas e faciais, de razões de velocidades escalonadas, para uso industrial e no setor da mobilidade. Em virtude do grande desenvolvimento das transmissões compostas por engrenagens faciais nos últimos anos, implementado por centros de pesquisa da área e por indústrias do setor aeronáutico, um dos objetivos deste trabalho foi estender o campo de aplicação dessas engrenagens para outros campos da engenharia. Inicialmente, mostra-se um estudo dos principais tipos de transmissões mecânicas presentes na indústria e, principalmente, no setor da mobilidade; área em que, usualmente, encontram-se os requisitos mais elevados de operação. Além disso, foi realizada uma revisão bibliográfica abordando tópicos importantes relacionados às engrenagens em geral e, mais especificamente, às transmissões cônicas e faciais. Esta revisão serviu de base para a implementação dos algoritmos para modelagem das engrenagens do sistema proposto. Para validar o conceito, um protótipo foi construído e testado, tendo como principal objetivo a comprovação da viabilidade e eficácia do sistema proposto, tanto na transmissão do movimento como na alteração da razão de velocidades. Realizados os testes, observou-se que, efetivamente, o sistema atendeu aos atributos funcionais especificados. Para a construção desse protótipo, as engrenagens envolvidas passaram por um processo de modelagem matemática, seguida pela modelagem sólida em software de CAD e pela fabricação em centro de usinagem. Para complementar o estudo, foi implementada uma rotina baseada nas normas AGMA, com foco na determinação das dimensões do pinhão, componente mais crítico do sistema. Desta forma, este trabalho permitiu avaliar os aspectos funcionais e elaborar um procedimento de projeto das engrenagens que compõem a transmissão proposta, concluindo que esta apresenta características herdadas das engrenagens faciais - facilidade de fabricação com custos competitivos - bem como características que a tornam adequada para operação automática em aplicações com alta taxa de flutuação da carga de trabalho, quais sejam: pequena variação da relação de transmissão e simplicidade do mecanismo de alteração da relação de velocidades. / This work was developed with the aim of propose a multi-speed mechanical gear drive based on face and bevel gears, for industrial and mobility field applications. Because of the recent great development of face gears, implemented by gear research centers and by aeronautical industry, one of the present work objectives was the extension of the application of these gears to other areas. The text begins with a brief review of the most used mechanical transmissions in the industry and, mainly, in the mobility field, where usually are found the higher loading and operation requirements. Also, important topics related to all gear transmissions and, more specifically, to bevel and face gears are presented. This review gave support for the algorithms implemented for the gears modeling. In sequence, for concept validation, a prototype was constructed and tested. The main objective of this prototype was proving that the original concept was viable and effective to transmit motion and change the ratio of velocities. After the tests, it was observed that, effectively, the system attended to specified functional attributes. For prototype construction, the related gears have been mathematically modeled, which was followed by the solid modeling in a CAD software and, finally, by the manufacturing process in a CNC milling machine. To extend the knowledge about the proposed transmission, an algorithm based on AGMA standards was implemented to assist in the analysis process related to the pinions, which are the most critical components of the system. As a result, this work allowed to validate the functional aspects and to elaborate a gear design procedure for the proposed system. Such system presents features inherited from face gears - constructive and manufacturing simplicity, meaning competitive costs -as well as features that make it adequate for automatic operation in high working load floating rates, which are: small ratio of velocities variation and mechanical simplicity of gears changing mechanism.

O presente trabalho foi desenvolvido com o intuito de propor um sistema de transmissão mecânica baseado em engrenagens cônicas e faciais, de razões de velocidades escalonadas, para uso industrial e no setor da mobilidade. Em virtude do grande desenvolvimento das transmissões compostas por engrenagens faciais nos últimos anos, implementado por centros de pesquisa da área e por indústrias do setor aeronáutico, um dos objetivos deste trabalho foi estender o campo de aplicação dessas engrenagens para outros campos da engenharia. Inicialmente, mostra-se um estudo dos principais tipos de transmissões mecânicas presentes na indústria e, principalmente, no setor da mobilidade; área em que, usualmente, encontram-se os requisitos mais elevados de operação. Além disso, foi realizada uma revisão bibliográfica abordando tópicos importantes relacionados às engrenagens em geral e, mais especificamente, às transmissões cônicas e faciais. Esta revisão serviu de base para a implementação dos algoritmos para modelagem das engrenagens do sistema proposto. Para validar o conceito, um protótipo foi construído e testado, tendo como principal objetivo a comprovação da viabilidade e eficácia do sistema proposto, tanto na transmissão do movimento como na alteração da razão de velocidades. Realizados os testes, observou-se que, efetivamente, o sistema atendeu aos atributos funcionais especificados. Para a construção desse protótipo, as engrenagens envolvidas passaram por um processo de modelagem matemática, seguida pela modelagem sólida em software de CAD e pela fabricação em centro de usinagem. Para complementar o estudo, foi implementada uma rotina baseada nas normas AGMA, com foco na determinação das dimensões do pinhão, componente mais crítico do sistema. Desta forma, este trabalho permitiu avaliar os aspectos funcionais e elaborar um procedimento de projeto das engrenagens que compõem a transmissão proposta, concluindo que esta apresenta características herdadas das engrenagens faciais - facilidade de fabricação com custos competitivos - bem como características que a tornam adequada para operação automática em aplicações com alta taxa de flutuação da carga de trabalho, quais sejam: pequena variação da relação de transmissão e simplicidade do mecanismo de alteração da relação de velocidades. / This work was developed with the aim of propose a multi-speed mechanical gear drive based on face and bevel gears, for industrial and mobility field applications. Because of the recent great development of face gears, implemented by gear research centers and by aeronautical industry, one of the present work objectives was the extension of the application of these gears to other areas. The text begins with a brief review of the most used mechanical transmissions in the industry and, mainly, in the mobility field, where usually are found the higher loading and operation requirements. Also, important topics related to all gear transmissions and, more specifically, to bevel and face gears are presented. This review gave support for the algorithms implemented for the gears modeling. In sequence, for concept validation, a prototype was constructed and tested. The main objective of this prototype was proving that the original concept was viable and effective to transmit motion and change the ratio of velocities. After the tests, it was observed that, effectively, the system attended to specified functional attributes. For prototype construction, the related gears have been mathematically modeled, which was followed by the solid modeling in a CAD software and, finally, by the manufacturing process in a CNC milling machine. To extend the knowledge about the proposed transmission, an algorithm based on AGMA standards was implemented to assist in the analysis process related to the pinions, which are the most critical components of the system. As a result, this work allowed to validate the functional aspects and to elaborate a gear design procedure for the proposed system. Such system presents features inherited from face gears - constructive and manufacturing simplicity, meaning competitive costs -as well as features that make it adequate for automatic operation in high working load floating rates, which are: small ratio of velocities variation and mechanical simplicity of gears changing mechanism.

O presente trabalho foi desenvolvido com o intuito de propor um sistema de transmissão mecânica baseado em engrenagens cônicas e faciais, de razões de velocidades escalonadas, para uso industrial e no setor da mobilidade. Em virtude do grande desenvolvimento das transmissões compostas por engrenagens faciais nos últimos anos, implementado por centros de pesquisa da área e por indústrias do setor aeronáutico, um dos objetivos deste trabalho foi estender o campo de aplicação dessas engrenagens para outros campos da engenharia. Inicialmente, mostra-se um estudo dos principais tipos de transmissões mecânicas presentes na indústria e, principalmente, no setor da mobilidade; área em que, usualmente, encontram-se os requisitos mais elevados de operação. Além disso, foi realizada uma revisão bibliográfica abordando tópicos importantes relacionados às engrenagens em geral e, mais especificamente, às transmissões cônicas e faciais. Esta revisão serviu de base para a implementação dos algoritmos para modelagem das engrenagens do sistema proposto. Para validar o conceito, um protótipo foi construído e testado, tendo como principal objetivo a comprovação da viabilidade e eficácia do sistema proposto, tanto na transmissão do movimento como na alteração da razão de velocidades. Realizados os testes, observou-se que, efetivamente, o sistema atendeu aos atributos funcionais especificados. Para a construção desse protótipo, as engrenagens envolvidas passaram por um processo de modelagem matemática, seguida pela modelagem sólida em software de CAD e pela fabricação em centro de usinagem. Para complementar o estudo, foi implementada uma rotina baseada nas normas AGMA, com foco na determinação das dimensões do pinhão, componente mais crítico do sistema. Desta forma, este trabalho permitiu avaliar os aspectos funcionais e elaborar um procedimento de projeto das engrenagens que compõem a transmissão proposta, concluindo que esta apresenta características herdadas das engrenagens faciais - facilidade de fabricação com custos competitivos - bem como características que a tornam adequada para operação automática em aplicações com alta taxa de flutuação da carga de trabalho, quais sejam: pequena variação da relação de transmissão e simplicidade do mecanismo de alteração da relação de velocidades. / This work was developed with the aim of propose a multi-speed mechanical gear drive based on face and bevel gears, for industrial and mobility field applications. Because of the recent great development of face gears, implemented by gear research centers and by aeronautical industry, one of the present work objectives was the extension of the application of these gears to other areas. The text begins with a brief review of the most used mechanical transmissions in the industry and, mainly, in the mobility field, where usually are found the higher loading and operation requirements. Also, important topics related to all gear transmissions and, more specifically, to bevel and face gears are presented. This review gave support for the algorithms implemented for the gears modeling. In sequence, for concept validation, a prototype was constructed and tested. The main objective of this prototype was proving that the original concept was viable and effective to transmit motion and change the ratio of velocities. After the tests, it was observed that, effectively, the system attended to specified functional attributes. For prototype construction, the related gears have been mathematically modeled, which was followed by the solid modeling in a CAD software and, finally, by the manufacturing process in a CNC milling machine. To extend the knowledge about the proposed transmission, an algorithm based on AGMA standards was implemented to assist in the analysis process related to the pinions, which are the most critical components of the system. As a result, this work allowed to validate the functional aspects and to elaborate a gear design procedure for the proposed system. Such system presents features inherited from face gears - constructive and manufacturing simplicity, meaning competitive costs -as well as features that make it adequate for automatic operation in high working load floating rates, which are: small ratio of velocities variation and mechanical simplicity of gears changing mechanism.

A handheld heavy-duty nut runner, commonly used to assemble windmills and oil pipe lines, and capable of producing 4100 Nm of torque, experiences low cycle fatigue and usually fails after 20 000 cycles at the specified torque. A full assembly Finite element model of the last stage of the four-stage planetary gearbox is constructed and simulated over one complete load cycle. The results from the simulation is compared with, and used to verify a KISSsoft simulation of the same model. Using the Finite Element model, a parametric optimization is performed using a full factorial design. The results show that misalignment issues are difficult to prevent due to the planetary gearbox design. Comparing the two models shows similar characteristics and stress levels but that local differences are common. A proposed design improvement results in better load distribution in the planet – ring interaction, which was previously impaired compared to the planet – sun interaction due to deformation induced misalignment. The result shows that by balancing the rotational stiffness of the side 1 and side 2 carrier pin mountings, it is possible to reduce the contact misalignment and improve the load distribution in the gearbox. / En handhållen mutterdragare vars användningsområde innefattar bland annat montering av vindkraftverk och oljeledningar, producerar ett vridmoment om 4100 Nm. På grund av det här havererar vanligtvis verktyget av utmattning vid ca 20 000 cykler, något som tros vara kopplat till vinkelfel som uppkommer vid deformation av verktygets växellåda. Vinkelfelen resulterar i att lastfördelningen mellan kugghjulen blir skev och spänningskoncentrationer uppstår. Finita elementmetoden används för att undersöka uppkomsten av vinkelfelen och en komplett modell av hela det sista steget i den fyrstegade planetväxellådan undersöks. Simuleringen jämförs med en liknande modell i KISSsoft, dels för att bekräfta resultatet från simuleringen, dels för att undersöka skillnader och svagheter i de båda modellerna. FE-modellen används även för att bygga upp en parametrisk optimering baserat på faktoriell design. Resultatet visar att vinkelfel är svårt att motverka på grund av växellådans design och konfiguration. Jämförelsen av de två simuleringsmodellerna uppvisar liknande karaktärsdrag och spänningsnivåer men att lokala skillnader finns mellan de båda modellerna. Optimeringen resulterar i en föreslagen designförändring som visar sig förbättra lastfördelningen i planet – ring – interaktionen utan att påverka lastfördelningen i planet – sol – interaktionen. Det här är att föredra eftersom lastfördelningen mellan planet och sol är bättre än lastfördelningen mellan planet och ring. Resultatet visar också att det är möjligt att minimera vinkelfelet mellan kontaktytorna, och förbättra lastfördelningen i växellådan genom att balansera rotationsstyvheten på var sida om planeten i planetbäraren.

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The general trend in gear industry is an increased focus on gear transmission efficiency. This thesis focuses on the understanding of how different gear manufacturing methods – particularly the contribution of the running-in process – affect the surface characteristics and friction response, with the purpose of increasing gearbox efficiency. The thesis consists of a summary and five appended papers. The research hypothesis in paper A and paper B was that the dry elastic contact area ratio is a descriptive parameter for the contact condition. Paper A deals with the influence of manufacturing method on the initial contact conditions. The emphasis in paper B is the changes that occur during running-in and correlating these changes to design requirements. Paper C examines the influence of manganese phosphate coating and lubricants, with respect to friction and the risk of scuffing at the initial contact. Paper D examines the effect of running-in load on the friction response for different surfaces. In paper E, the question of whether the load during running-in influences the gear mesh efficiency is further expounded. The main conclusions of this thesis are that the running-in influences the gear mesh efficiency; a high running-in load enhances the gear mesh efficiency. The difference in mesh efficiency is in the range of one tenth of a per cent. Thus, the influence of running-in cannot be neglected because it is in the same order of magnitude as reported for other gear efficiency enhancements. Furthermore, the dry elastic contact area ratio presents a descriptive measure of how surface topography influences the contact, at both a global (form deviation) and local (roughness) level. The surface topography caused by the manufacturing method has a significant influence on the contact area ratio. Shaving was found to have the highest contact area ratio, and would therefore be the best choice if deviations from case hardening could be minimised. It was also confirmed that surfaces coated with manganese phosphate raise the limiting load for scuffing failure up to 13 times compared to the uncoated ground equivalent. / <p>QC 20141002</p>

This thesis focuses on reliability when testing gear efficiency and on how gear mesh efficiency can be increased without detrimental effects on the gears. Test equipment commonly used in gear research was analysed to identify important parameters for gear efficiency testing. The effect of the bearing model's load-dependent losses on gear mesh efficiency was also investigated. Two different surface finishes of gears, ground and superfinished, were investigated to determine how two different load levels during running-in affect gear mesh efficiency and changes in surface roughness. Efficiency and gear temperature were also measured for ground and superfinished gears with dip lubrication, as well as two different forms of spray lubrication (before and after gear mesh contact). Tests on a gear test rig, showed that different assemblies of the same test setup can yield different measurements of torque loss. The applied bearing model had a significant effect on the estimated gear mesh efficiency. The mesh efficiency of ground gears is affected by the running-in procedure, with a higher running-in load resulting in a higher mesh efficiency than a lower load. This effect was not seen for superfinished gears, which show the same gear mesh efficiency for both running-in loads. Gearbox efficiency increased with spray lubrication rather than dip lubrication. The gear mesh efficiency increased, and thus gear temperatures were reduced, when superfinished gears were used rather than ground gears. A lower gear temperature was measured when gears were spray lubricated at the mesh inlet rather than the mesh outlet. / <p>QC 20170314</p>