| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 95 === Two of the most popular chain drives in power transmission applications are roller chains and silent chains. Each of the two types of chains has its characteristic and can be applied to different fields. Roller chains are superior in wear-resistance and they are suitable for low-speed and high-torque applications. Silent chains have the advantage of low noise and are suitable for high-speed and high transmission efficiency applications. This thesis aims at designing new chains by considering the characteristics of both types of chain. Then the innovative chains are applied to bicycle transmissions, and the prototypes are built and tested.
This thesis discusses two kinds of design: double-tooth and single- tooth link plates. Based on conjugate theory, the motion analyses of chains with double-tooth and single-tooth link plates are conducted. These tooth-shaped chains are analyzed by using the techniques of tooth contact analysis with geometric constraints and force constraints incorporated.
The tooth contact analysis shows that a double-tooth link plate undergoes the following five stages: tight-span, left-tooth contact, stationary, right-tooth contact, and fixed stages. For one kind of single- tooth chains, its link plates undergo only tight-span and fixed stages. For the other kind of single-tooth chains, its link plates undergo only tight-span and contact stages. There is no fixed stage in this case, and multiple link plates are in contact with the sprocket. Comparing the chordal actions of double-tooth and single-tooth chains, the single-tooth design is better because its chordal action is smaller. This thesis also reports the application of the double-tooth chains to the bicycle transmission system and shows that it is indeed practical and useable.
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