The Dynamic Analysis Of The Engine Timing Chains

Silent chain drive is widely used in the timing mechanism of gasoline engine, such as motorcar and motorcycle engine. However the polygon movement and the meshing contact of silent chain drive are great obstacles in the further development and application of the silent chain mechanism. In this thesis, the finite element software of ANSYS is used to analyze the stress and deformation of the tooth outline when the sprocket wheel engages with the silent chains and also analyze the natural frequency of the tension side chains.The deliver force of the silent chain drive and the contact normal force are calculated by means of the engagement theory between the sprocket wheel and the silent chains. Straight-tooth and involute-tooth sprocket wheel which the pitch is 6.35mm are also established on the basis of the 3-D modeling technology of the Pro/E. The assemblage is also finished between sprocket wheel and the silent chains.Then, the procedures of finite analysis are introduced after establishing the finite model of the silent chain drive. The stress and deformation of the tooth outline are analyzed when the gear wheel engages with the silent chains as research the post process results. The processed of the analysis can be proved after comparing the simulation results with the theoretical results which researched by Hertz. The analysis results show that the stress and deformation are concentrated the top of the tooth outline when straight-tooth sprocket wheel engages with the chains. However, the stress and deformation are focused the middle position when involute-tooth sprocket wheel engages with the chains and the results are also decreased from both sides to the middle position of the tooth outline. It also shows that the results of the simulation are right to the results of theory, and also proves the parameter of the simulation in ANSYS right by compared above two results.Finally, ANSYS is used to analyze the free frequency and the model of the tension side chains as the solid model and the simplified model. The experiment of measuring the free frequency of the experiment table and the tension slide is finished on the JCY experiment table. It also researches the influence of the whirling speed by the deflection of the wheel and the polygon movement. The reasons of the deviation between the experiment results and the theory results are also analyzed .The research results show that ANSYS is well used for simulating the model of the tension side chains of the silent chain, also the result proves that the method of calculating the natural frequency for the traditional roller chains is also fit for the silent chains.The method for analyzing the silent chain in ANSYS is given and the finite element method is first used to the modal simulation of the silent chain in this thesis.