The epicyclic gear mechanisms are widely used in the automatic transmissions for automobiles, and can provide several speed ratios by the controls of the input and fixed links with clutches and brakes. In order to increase the number of speed ratios, two or three embedded clutches are adapted in the automatic transmissions. However, the design of automatic transmissions with one embedded clutch has been hitherto ignored. Thus, the purpose of this work is to develop a systematic methodology for the design of automobiles automatic transmissions with one embedded clutch. First, the design specifications are established based on the requirements of the epicyclic automatic transmissions. Next, a procedure of the conceptual synthesis is developed to enumerate the epicyclic gear mechanisms with one embedded clutch. The corresponding atlas of the epicyclic gear mechanisms with two fundamental geared entities are established. Finally, a method is created to arrange the clutches and brakes into epicyclic gear mechanisms. Then the numbers of the teeth of gears are calculated by an analytical way. The result of this research shows that five five-speed automatic transmission and one seven-speed automatic transmission are synthesized. The associated efficiency for each speed is greater than 95%. This demonstrates the feasibility of the proposed methodology.

Epicyclic-type automatic transmissions are widely used in automobiles, it provide different speed ratio by control different elements to be an input or a fixedness with clutches and brakes. There are many researches about the Epicyclic-type automatic transmissions, but the research of the arrangement of clutches and brakes is fewer, and lacked for a method for arranging the desired clutches and brakes quickly. Therefore, the purpose of this research is to develop a methodology for arranging the desired clutches and brakes. First, introduce a planar-graph representation and a number sequence which had been used in arranging desired clutches and brake for years. Second, explore the relationship between contracted graph and epicyclic gear mechanisms based on topology theorem. Then provide a systematical procedure to arrange desired clutches and brakes into epicyclic gear mechanisms. With the above method, can find seven types of feasible clutching sequence that havn¡¦t been discovered in 94 types of feasible clutching sequence. Then, the number of the teeth of all gears can be calculated, as a result, five types of six-speed automatic transmissions are found. Finally, build the model of all the nine-link two-DOF epicylic gear mechanism that can be used in six-speed automatic transmissions.

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

This thesis presents a unification of kinematic and force-based methods for the design and analysis of planetary gear trains along with a discussion of potential applications in tandem biking. Specifically, this thesis will provide a simple solution technique for the general case of a two-degree of freedom (2DOF) planetary gear train along with new graphical design aids. It will also address the use of epicyclic gear trains as a power coupling in a tandem bike. In the current literature, planetary gear trains are given a clear treatment with regard to the pure kinematics of the system, but little or no literature exists that includes the torques present in the system. By treating both the kinematics and torque balance of the most general case, this thesis attempts to fill a void in the current literature. After developing the solution to the general two-degree of freedom case using the Willis formula, a force analysis will be performed using the conservation of energy principle assuming zero losses. Once the total solution is known, nomographs will be presented as a simple design tool. These graphical aids enable the designer to simultaneously approximate both speeds and torques for the mechanism. After fully developing a satisfactory solution technique and design tools, these will be applied to the problem of coupling the power provided by the riders of a tandem bicycle. / Master of Science

This Bachelor of Science thesis consists of an efficiency evaluation and creation of atheoretical model for an Atlas Copcos epicyclic gearbox. The thesis starts with atheoretical chapter containing the fundamentals of epicyclic gearing and the build of thespecific gearbox investigated. The following chapter contains former testing and theoryof power losses in a gearbox. After the theory is explained the next chapter containstesting, compromises and assumptions during testing and also results from the testing.The next chapter explains the Matlab calculation program based on the theory andmeasurements. Finally the model is validated against reference a reference model andagainst real gearbox measurements followed by some closing conclusions. The finalmodel calculates the efficiency rather well and has a linear difference. The difference isstatic since some losses have been left out, it can be fixed with an empirical correctionfactor which corrects the values and predicts an acceptable efficiency. The correctionfactor for the surface roughness also decreases the difference.

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An epicyclic gear mechanism for automobile transmissions is a device which is connected from engine to driving wheels, and the main purpose is to maintain the revolution speed of engine to be in a desired working range while accelerating or decelerating the automobile. The epicyclic gear mechanisms for automobile transmissions in production are mostly Ravigneaux-type, Parallel-connected type and Lepelletier epicyclic mechanisms, and the Lepelletier epicyclic gear mechanisms is a device which is connected with a simple epicyclic gear mechanism besides the input end to increase the total number of speed ratios of an automatic transmission. For the incompletion in the relative design methodology, a systematic methodology of designing Lepelletier epicyclic gear mechanisms for automobile transmission is described. At first, fundamental and gear-shifting operations of the Lepelletier-type automatic transmissions is introduced, and the basic principles of lever analogy is explained, the gear ratio¡¦s analysis for Lepelletier epicyclic gear mechanisms is illustrated to establish the design requirements. Secondly, gearing-sequence is devised base on the lever analogy diagrams, and a systematical procedure to arrange desired clutches and brakes into epicyclic gear mechanisms is provided, then the number of the teeth of all gears can be calculated. At last, the six-speed and eight-speed Lepelletier automatic transmissions are designed base on the above design procedure. The results of this work obtain 19 types of automatic transmission which could reach six-speed.

There are many advantages of Epicyclic gear type automobile transmissions. It is composed more densely and weights lighter. It provides higher gear ratio and can transmit power differentially. Therefore, this type of transmissions are applied to almost every automobiles in recent years. However, the design process of an Epicyclic gear type automobile transmission is more complicated than Counter shaft type one. In the world, there are just two kinds of 8-speed Epicyclic gear type automobile transmission in production. This study introduced a design methodology of Parallel epicyclic gear type automobile transmission by decomposing and recomposing of Lever diagram. First we drew the Lever diagram from given rotation speed ratios. Next we listed all 3-point lever diagrams which are decomposed from the original Lever diagram, and deleted those with unreasonable value of K. Then we listed all combinations of 3-point lever diagram which composed the original Lever diagram, and we got all feasible epicyclic gear train mechanisms. After choosing feasible epicyclic gear train mechanism, we set up necessary clutches and breakes in clutch graphs. Finally, based on the clutch graph, we draw the schematic diagram of mechanisms, and embodies out results. Methodology of this study is better than old ones because our methodology based on Lever diagram did not need to find the usable mechanisms from the catalog of epicyclic gear train mechanisms. Thus, the new methodology simplifies the process of designing a epicyclic gear type automobile transmission.

An epicyclic-type automatic transmission is a device that is connected to the back of an engine and sends the power from the engine to the drive wheels. Its job is to keep the engine within a certain angular velocity. For the development of multi-speed parallel-connected automatic transmission for automobiles, the related configuration design methods are still tedious and prone to human error. Therefore, the purpose of this research is to present an efficient methodology for the systematic design of the parallel-connected automatic transmission for automobiles. First, fundamentals and gear-shifting operations of the parallel-connected automatic transmission are illustrated to establish the design requirements, and the theory of the analysis of speed ratios for epicyclic-type automatic transmission is derived based on the concept of lever analogy. Next, one simple clutching-sequence synthesis methods are proposed and illustrated, based on the lever analogy, and the design theory and the procedure of clutch configuration of epicyclic-type automatic transmission are developed. With the above methods, designs of six-speed and eight-speed parallel-connected automatic transmission. Finally, the complete atlas of six-speed and eight-speed parallel-connected automatic transmission can be systematically synthesized from the data of given speed ratios. This proposed design method can also be applied to the development and design of multi-speed parallel-connected automatic transmissions.

An epicyclic-type automatic transmission is a device which is connected from engine to driving wheels, and the main purpose is to maintain the revolution speed of engine to be in a desired working range while accelerating or decelerating the automobile. The epicyclic -type automatic transmissions in production are mostly Ravigneaux-type epicyclic mechanisms, and in recent year, the development of automatic transmissions for automobile is oriented to the orientation of setting an single epicyclic gear mechanism instead of the input to bring various inputs of revolution speed to increase the total number of speed ratios of an automatic transmission, and such type of epicyclic is called combinational epicyclic-type automatic transmissions for automobiles. For the incompletion in the relative design methodology, a systematic methodology of designing mechanism and clutching-sequence of combinational epicyclic-type automobile transmission is described. First, fundamental principle of the combination and operations of automatic transmissions are analyzed to establish the design requirements. Second, a procedure of structure synthesis of combinational epicyclic-type automobile transmission is brought up which the planar graphic method is applied for. Third, based on Speed Ratio Relationship of each clutching sequence, a procedure of gearing-sequence is introduced. Finally, on the basis of the analytic method, the teeth of gears is to be clarified. The result of this work obtains five types of the combinational epicyclic-type automatic transmissions which could reach six speeds.