Positioning and orientation error measurement and assembly coaxiality optimization in rotors with curvic couplings

Abstract In the assembly of aero-engine rotors, coaxiality is the major technical index, which has an important influence on the performance and service life of the whole machine. This article studies the optimization problem of assembly coaxiality of multistage rotors with curvic couplings, and proposes a method for indirectly measuring the positioning and orientation errors between the mating surfaces of a single-stage rotor with curvic couplings. This method can solve the problem that the positioning and orientation errors cannot be directly measured due to the tooth structure. Then the mathematical expression between the coaxiality after assembly and the assembly phase is derived based on the positioning and orientation errors of the rotors of each stage, which can realize the prediction and optimization of the assembly coaxiality. Finally, it verifies the prediction and optimization effect through the assembly experiment of multistage rotors with curvic couplings. Results indicate that: the maximum coaxiality prediction errors for the two-stage and four-stage rotors assembly under ten different assembly phases are 15.63% and 8.62%, respectively. Compared with direct assembly, the coaxiality of optimized assembly is reduced by 83.3% and 48.7%, respectively. It proves that this method can better realize the prediction and optimization of the assembly coaxiality of multistage rotors with curvic couplings.