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When engaging a new gear in an automated manual transmission (AMT) the gear needs to be synchronized with the main shaft's angular velocity in the gearbox. This is so that the parts can be connected through a cog wheel and torque can be transferred. To synchronize the angular velocities, mechanical synchronization components can be used. These components synchronize the velocities during the engagement and can be used with larger differences in angular velocities. Should no mechanical synchronization components be used it puts higher demands on the components rotating at similar velocities to avoid mechanical wear and ensure that the gear can be engaged. In today's systems without mechanical synchronization components the gear is engaged when the angular velocities are within a certain difference. This leads to random angle connections between the cogs and gaps that are to be engaged on the gear and main shaft. This can lead to extended or incomplete engages should the components connect cog to cog. This thesis evaluates the possibility to control the angle at which the components connect by using existing sensor signals in the studied system and known parameters. A model of the system is created and simulated to evaluate the probability of predicting the system over the gear engage. Results indicate that it is possible to predict the connection angle close enough to its real value so that a control strategy could be implemented to control the angle to some level.

The task of constructing a transmission has been provided to us by Digital Engineering, which is a company located in Hovmantorp. After meeting with Digital Engineering we started immediately with the brainstorming to find different ideas with pen and paper. After having presented a number of concepts for the company, we had finally chosen a winner. For the gearbox to be able to work in a good way the tension must never exceed the strain limit of the material. A prototype of the gearbox was produced by TKB Modell. Standard components that are available have been purchased from Sverull AB in Växjö.

Condition monitoring of epicyclic gearboxes through vibration signature analysis, with particular focus on time domain methods and the use of adaptive filtering techniques for the purpose of signal enhancement, is the central theme of this work. Time domain filtering methods for the purpose of removal of random noise components from periodic, but not necessarily stationary or cyclostationary, signals are developed. Damage identification is accomplished through vibration signature analysis by nonstationary timefrequency methods, belonging to Cohen’s general class of time-frequency distributions, strictly based in the time domain. Although a powerful and commonly used noise reduction technique, synchronous averaging requires alternate sensors in addition to the vibration pickup. For this reason the use of time domain techniques that employ only the vibration data is investigated. Adaptive filters may be used to remove random noise from the nonstationary signals considered. The well-known Least Mean Squares algorithm is employed in an adaptive line enhancer configuration. To counter the much discussed convergence difficulties that are often experienced when the least mean squares algorithm is applied, a new unconditionally convergent algorithm based on the spherical quadratic steepest descent method is presented. The spherical quadratic steepest descent method has been shown to be unconditionally convergent when applied to a quadratic objective function. Time-frequency methods are succinctly employed to analyse the vibration signals simultaneously in the time and frequency domains. Transients covering a wide frequency range are a clear and definite indication of impacting events as gear teeth mate, and observation of such events on a timefrequency distribution are used to indicate damage to the transmission. The pseudo Wigner-Ville distribution and the Spectrogram, both belonging to Cohen’s general class of time-frequency distributions are comparatively used to the end of damage identification. It is shown that an unconditionally convergent adaptive filtering technique used in conjunction with time-frequency methods can indicate a damaged condition in an epicyclic gearbox, where the non-adaptively filtered data did not present clear indications of damage. / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / MEng / MEng / unrestricted

The master´s thesis concentrates on a project of condensing steam turbine for existing heating plant with back pressure turbine. The master´s thesis subject consists in the thermodynamic calculation of regulating stage and turbine stages. Design documentation is worked up according to the calculated record. From calculated power of turbine is worked a basic project of gearbox and disposal arrangement system.

The following thesis document researches into creating a model to represent the behavior of a wind turbine gearbox. This model is developed based on the overall parameters of a NORDEX N90 2.5MW wind turbine developed by a German company Nordex SE. This research focuses on the combination of a flexible body and a multibody dynamics analysis software. This is done through the usage of MSC ADAMS, a multibody dynamic analysis program, and MSC Patran/Nastran, a finite element analysis software, and its associated solver. The model is created to show the vibration patterns of a healthy gearbox with rigid bodies, with a flexible body, and with a defect applied on a particular gear in the planetary gear systems that is representative of the N90 wind turbine. The flexible body incorporation allows for stress analysis of different gear teeth at different locations. Using this model a vibration signature is generated for a specific type of defect.

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In the current literature, split path gear trains are analyzed for use in helicopter transmissions and marine gearboxes. The goal in these systems is to equalize the torque in each path as much as possible. There are other gear trains where the operator intends to hold the torque split unevenly. This allows for control over the gearbox bearing loading which in turn has a direct effect on bearing stiffness and damping characteristics. Having control over these characteristics is a benefit to a designer or operator concerned with suppressing machine vibration. This thesis presents an analytical method for analyzing the torque in split path gear trains. A computer program was developed that computes the bearing loads in various gearbox arrangements using the torque information gathered by the analytical method. A case study is presented that demonstrates the significance of the analytical method in troubleshooting an industrial gearbox that has excessive vibration. / Master of Science

Wind is one of the most promising resources in the renewable energy portfolio. Still, the cost of electrical power produced by small wind turbines impedes the use of this technology, which can otherwise provide power to millions of homes in rural regions worldwide. To encourage their use, small wind turbines must convert wind energy more effectively while avoiding increased equipment costs. A variable ratio gearbox (VRG) can provide this capability to the simple low-cost fixed-speed wind turbine through discrete operating speeds. The VRG concept is based upon mature technology taken from the automotive industry and is characterized by low cost and high reliability. A 100 kW model characterizes the benefits of integrating a VRG into a fixed-speed stall-regulated wind turbine system. Simulation results suggest it improves the efficiency of the fixed-speed turbine in the partial-load region and has the ability to limit power in the full-load region where pitch control is often used. To maximize electrical production, mechanical braking is applied during the normal operation of the wind turbine. A strategy is used to select gear ratios that produce torque slightly above the maximum amount the generator can accept while simultaneously applying the mechanical brake, so that full-load production may be realized over greater ranges of the wind speed. Dynamic programming is used to establish the VRG ratios and an optimal control design. This optimization strategy maximizes the energy production while insuring that the brake pads maintain a predetermined service life. In the final step of the research, a decision-making algorithm is developed to find the gears that emulate the ratios found in the optimal control design. The objective is to match the energy level as closely as possible, minimize the mass of the gears, and insure that tooth failure does not occur over the design life of the VRG. Recorded wind data of various wind classes is used to quantify the benefit of using the VRG. The results suggest that an optimized VRG design can increase wind energy production by roughly 10% at all of the sites in the study. / text

Goal of the Master Thesis was to design conception of electric vehicle driveline, which is able of torque vectoring between each wheel independently and to design front axle gearbox. The aim was to use up the car on race track and to test dynamic properties of electric vehicle for follow-up development. Due to determined requirements and possible solutions the conception of driveline was designed and basic parameters were defined. The main part of the thesis contains a design of gearbox including strength calculation of gearing, the control of shafts to fatigue and elasticity limiting states, life of selected bearings. Gearbox case was subjected to FEM analysis. The last chapter uses simulation to gain vehicle acceleration. Designed electric driveline is applicable to other sport vehicles after some modifications.