| Summary: | 碩士 === 國立中興大學 === 機械工程學系所 === 95 === Step Chain, also named Escalator Chain, carries the steps of escalators. It is one type of roller chain. The advantages of roller chain includes no slippage between chain and sprocket teeth, allowing chains to carry heavy loads under long distance, and operating in severe environments such as high temperatures, oily areas, dusty. Most time, escalator is used to carry passengers for high-rise mass transportation. Therefore, the step chain has been designed based on roller chain. Since the step chain is always used under heavy loading, so the strength of chain becomes very important. Loading is transmitted by chain and sprocket through the contact between pin, roller, barrel, link-plate, and tooth. For engagement with the roller of step chain, special design for sprocket is needed. More teeth on sprocket can reduce noise and contact force due to chordal action.
Most designers often use numerical techniques such as finite element method or dynamic simulation to solve three-dimensional engineering problems. In this research, we have analyzed the situation of the engaging motion between chain and sprocket by using Computer-Aided Engineering technique. The engaging force between chain and sprocket, the force on bushing, link-plate, and pin are analyzed by a simplify chain model. A computer model based on the wear testing machine has been constructed for simulating different applications. The condition of each part of step chain is analyzed under different speed, loading, and preloading. The stress-life CAE method is used to analyze chain-life. By this method, the fatigue-life of link-plate during operation is discussed for different loading conditions. The purpose of this research is to provide a design guide and reference for the development of escalator chain.
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