Design Method Of Curvic Couplings

Curvic couplings are used extensively within the aero-engine industry and industrial gas turbins, they are mainly being used for coupling and fixing compressor/turbine rotors.Owing to the special shape of the curvic teeth, curvic couplings have some advantages such as strong load bearing ability, positioning precision,automatic centering and assembling easily. Unfortunately, domestic design technology and technology accumulation level are low.Thus,it is necessary and significant to carry out the design method of curvic couplings.The main work of this thesis is summarized as follows,(1) Curvic couplings design method based on parametric modeling have been carried out. This paper first summarizes the structure required all parameters, calculates the basic geometric parameters, and give addendum chamfering, bottom and dedendum transition arc these key local details of the design method.At the same time, the grinding wheel top width, which is the key parameter of manufacturing curvic couplings, and grinding wheel basic outline design method are established. Through the simulation of its processing principle established curvic couplings parametric model. At last, combined with EGD-3strength and life design criterion, and gives the design method of the process. According to the curvic couplings design results show that the established structure design method is effective and reliable.(2) Curvic couplings optimization model and optimization method have been established. Curvic couplings of the maximum equivalent stress minimum was selected as the optimization objective, transition arc radius and curvic couplings inside diameter as the optimization design variables. This method used agent model combined with genetic algorithm optimization technique and the three dimensional finite element analysis technology and automatic parametric modeling technology. Through the curvic couplings structure optimization analysis results show that the established optimization model and optimization method is effective.(3) Two different structure of the curvic couplings has been designed and the structure optimization has been undertaken. By considering the contact condition of three dimensional nonlinear finite element stress analysis, and the results show that the strength and life of improved curvic couplings structure are enhanced, the objective function value, which is the maximum equivalent stress of curvic couplings, was reduced by6.1%and19.7%respectively by comparing a certain type of curvic coupling, that was used in an aero-engine. (4) Curvic couplings structure influence factors analysis have been carried out and obtained the related influence law. First of all, analysis was undertaken to account for the effeces of some design parameters, through the research shows that the coefficient of friction, inside diameter and the radius of dedendum transition arc were great influenced the maximum equivalent stress of curvic couplings. Secondly, it is concluded that with the speed increase, dedendum transition arc stress increases rapidly, while the effect of torque and temperature is less and the tooth surface contact stress distribution mainly affected by preload. Finally, through the three different number of teeth of curvic couplings structure optimization analysis found that:with the increase of the number of teeth, the maximum equivalent stress decrease. Meanwhile, it is not too much difference in stress distribution by comparing concave as a working component to convex as one.