Planetary gear trains have the advantages of compactness, light weight, high speed reduction and differential drive, and can provide several speed ratios by means of selecting different clutches and brakes. They are widely used in the automatic transmissions for automobiles. The purpose of this work is to develop a systematic methodology for the design of automatic transmissions for automobiles. First, the specification is established by using concept of fundamental geared entities. Second, a methodology of structure synthesis is developed for establishing gear trains graphs table with up to three fundamental geared entities. Third, a method for systematically enumerating all possible clutching sequences is established and a method for position of clutches and brakes is developed to establish automatic transmissions graphs table. Forth, a procedure for the selecting of a most efficient clutching sequence associated with a automatic transmission is developed. Finally, the systematic theory integrates preceding methodologies and a computer software package is to developed. The computer software package provides user a powerful tool to design automatic transmissions for automobiles.

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A multi-speed drive hub is one of important components in transmission system. The purpose of this work is to develop a system methodology for the design of multi-speed bicycle drive hubs. First, analyse multi-speed drive hub patents to identify the basic characteristics and design requirement of multi-speed drive hub. Second, using a systematized mathod to synthesize the feasible gear trains. Third, a method is proposed to determine the feasible multi-speed sequence tables for each gear train. Fourth, an analytic method is formulated to synthesize the gear ratios and gear teeth according to a set of desired speed ratios. Fifth, design and dispose governors of multi-speed drive hubs. The results of this work will be benefit to the development and design of multi-speed bicycle drive hubs.

Abstract In this thesis, a simple dynamic model of the planetary gear train system is developed. Because of the dynamic equations deriving from designing a planetary gear train system are complex and nonlinear, and the controller design is difficult. If we take the planetary gear train system as a pure speed-down mechanism, and then the accuracy of the planetary gear train system will lose. So, we develop the dynamic equations of the planetary gear train system concerning with the conception of friction losses. Furthermore, the MGA method is used to identify the parameters of this system. The modified genetic algorithm (MGA) is proposed from the simple genetic algorithm (SGA) with some additional strategies, such as Elitist and Extinction strategies. From the computer simulations and the experimented results, it is concluded that the parameters of this system searched by using MGA will be more precise than the parameters searched by using LMS.

­^¤åºK­n A multi-speed drive hub is one of important components in transmission system. The purpose of this work is to develop a system methodology for the design of multi-speed bicycle drive hubs by using a concept of combination. First, identify the basic characteristics and design requirement of combinative multi-speed drive hub. Second, using three combinative the useful gear trains. Third, a method is proposed to determine the feasible multi-speed sequence tables for each gear train. Fourth, an analytic method is formulated to synthesize the gear ratios and gear teeth according to a set of desired speed ratios. Fifth, a computer programs developed for the automatic analysis the transmission performance of drive hubs. The results of this work will be benefit to the development and design of multi-speed bicycle drive hubs.

A multi-speed drive hub is one of important components in transmission system. The purpose of this work is to develop a system methodology for the design of multi-speed bicycle drive hubs. First, identify the basic characteristics and design requirement of multi-speed drive hub. Second, using the useful gear trains. Third, a method is proposed to determine the feasible multi-speed sequence tables for each gear train. Fourth, an analytic method is formulated to synthesize the gear ratios and gear teeth according to a set of desired speed ratios. Fifth, the basic theory for transmission analysis of multi-speed drive hubs will be developed. The results of this work will be benefit to the development and design of multi-speed bicycle drive hubs.

The multi-speed internal gear hub of a bicycle is a well-closed gear shifting system that works perfectly under any challenging riding environment, and is developed specifically to improve fragile chain-drive derailleur using planetary gear trains. In recent years, bicycle internal hub gears have been developed toward multi-speed transmission, and in the development process of internal gear hubs, the structure of speed changing mechanism has changed from a single planetary gear train to multiple planetary gear trains, and is becoming more complex. The primary purpose of this Study aims to establish a systemized and efficient design process, and develop an effective theory and method for designing multiple-speed internal gear hubs with the design concept and common features of multiple-speed internal gear hub products developed in recent years, to favor the innovation and development of internal gear hubs. First, existing multiple speed internal hub products are analyzed and summarized for their basic features, limitations, and demands as the reference for the design of multiple speed internal gear hubs, and a catalog of usable planetary structures is systematically established with the coupling and connection of basic high and low ratio speed changing modules. Secondly, usable planetary structures that offer best performance of geometric progression speed ratio distribution of gear hub are matched with gear positions, and a table of gear sequence is confirmed; third, based on the maximum external diameter required by design, tooth numbers for every gear in a hub are defined according to the relationship between tooth number and speed ratio, as well as the gear sequences; and finally, the systematic design process above is applied to the development of an easy-to-use computer aided design software with the lowest possible number of variables using Visual Basic 6.0 for designers, in order to favor the innovation and development of internal gear hubs.

In current years, searching for substitute energy such as the wind and ocean power of renewable energy is an important subject due to the petroleum shortage. The gear box is the key mechanism in the system of wind and ocean power. Moreover, the main function of the system is to generate electricity by speeding up the rotative velocity. However, the power of environment changes momentarily and makes the turbine a variable input. In order to improve the efficiency of generating electricity, it should get the constant input to keep the high quality of generating electricity. First of all, the study focuses on the gear box and synthesizes a constant speed mechanism of planetary gear train which degrees of freedom is two. In the mechanism, inputs are the variable speed turbine and a constant speed motor. When they input the mechanism, a constant speed output will be made to supply the generator. Secondly, it is necessary to set up the real object of the constant speed mechanism of planetary gear train. Finally, observing the real condition from the experiment to prove the theory is correct.

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.

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