Abstract: The various types of error coupling transmission mechanisms and the dimensional tolerance optimization design of multi-faceted shafting assembly are analyzed by taking the multi-faceted shafting assembly as the research object. Monte Carlo method is used to simulate the measured size of assemly ring, and the mean value of radial run-out tolerance and its distribution law are obtained. A prediction method for the radial circle run-out of variable boundary circle is proposed, and the integrated cumulative error including the coaxiality and the matching tolerance of shaft hole is established. This method is extended to the assembly error modeling of complex assembly to realize the prediction of the radial run-out tolerance in the design. With the goal of accumulating the radial runout at the end of the assembly, the average assembly accuracy, assembly reliability, and processing cost are set as constraints, and the optimization of system structure and its component tolerances is performed. Taking the design of a certain type of torque converter as an example, the feasibility and practicability of this method for predicting the cumulative radial run-out tolerance of the shaft system are verified. Key

Key words: shaftingassembly, rotatingmachinery, radialcirclebeating, hydraulictorqueconverter, deliverymechanism, positiontoleranceprediction