Effect of planet pin position errors on the fatigue reliability of large aviation planetary systems

Planet pin position errors significantly affect the mechanical behavior of planetary transmissions at both the power-sharing level and the gear tooth meshing level, and its tolerance properties are one of the key design elements that determine the fatigue reliability of large aviation planetary systems. The dangerous stress response of planetary systems with error excitation is analyzed according to the hybrid finite element method, and the weakening mechanism of large-size carrier flexibility to this error excitation is also analyzed. In the simulation and analysis process, the Monte Carlo method was combined to take into account the randomness of planet pin position errors and the coupling mechanism among the error individuals, which provides effective load input information for the fatigue reliability evaluation model of planetary systems. In addition, a simulation test of gear teeth bending fatigue intensity was conducted using a power flow enclosed gear rotational tester, providing the corresponding intensity input information for the reliability model. Finally, under the framework of stress-intensity interference theory, the computational logic of total formula is extended to establish a fatigue reliability evaluation model of planetary systems that can simultaneously consider the failure correlation and load bearing time-sequence properties of potential failure units, and the mathematical mapping of planet pin positional tolerance to planetary systems fatigue reliability was developed based on this model. Accordingly, the upper limit of planet pin positional tolerance zone can be determined at the early design stage according to the specific reliability index requirements, thus maximizing the balance between reliability and economy.