Dynamic Analysis And Simulation Of The Automotive Air Compressor's Crank-Rod Mechanism

Crankshaft is one of the key components of piston compressor, which endures complex and alternating load, so it has complex dynamic characteristics and impacts compressor's reliability and life directly. Therefore, it has important practical significance to analyze the crankshaft from the theoretical and practical point of view. The simplified method of traditional design and analysis can't meet the corporation's needs, while the development of the multibody dynamics and finite element method makes it is possible to analysis the crankshaft dynamics response more accurately.In this thesis, the EQ1141G automotive air compressor was adopted as the researched object. Firstly, the movement law of crank-rod was introduced, its kinematics simulation was realized by using the MATLAB compile calculated program and the corresponding relation between piston's displacement and crank's angle of rotation was obtained, which is convenient for calculating the piston's displacement of each endpoint in the compressor's working process, so we can find the corresponding crank angle in no time.Secondly, on the basis of analyzing crank-rod's topology structure, the models of multi-rigid-body dynamics and multi-flexible-body dynamics were developed respectively by using the software ADAMS. Comparing the simulation results of the two models', we can know that relatively accurate analytical results can be provided for the interaction relation among rigid parts in the crank-rod mechanism and the interaction relation between the piston pin end and the piston pin by the two models. However, more reasonable and accurate results about the interaction relations between the crank and bearing can be acquired only by multi-flexible-body dynamics model.At last, taking the dynamic loads on crankshaft journal and crank pin acquired from the simulation by the flexible model and set it as boundary conditions about the dynamic response analysis. At the same time, ANSYS software was used to analyze the stress and deformation of the crankshaft more accurately to get the dynamic response of crankshaft in its working process. In this way, we can find the dangerous positions of crankshaft at the time of working, so to provide a theoretical basis for its optimization.The results of this thesis indicate that using the virtual prototype technology with the method of FEA can get more accurate results about the dynamic response analysis of the compressor crankshaft. It has great meanings, such as amending the crankshaft, raising the design level and improving the compressor's performance. Generally speaking, it is an economical, effective and scientific method.