Dynamic characteristics and lightweight optimization design of the main reduction gear structure of a certain light helicopter

A light helicopter is widely used in low-altitude transportation. How to improve gear transmission efficiency and enhance the smoothness, durability and reliability of the traditional face gear transmission system are urgent problems to be solved. To carry out the weight reduction and dynamic characteristic analysis of the face gear body structure, the paper proposes a face gear body structural lightweight optimization design method that combines topological optimization and parametric optimization. The 3D model of the face gear was established with the finite element method. The solid isotropic material with penalization topological optimization and the sensitivity analysis of the face gear body structure were carried out to select the key design parameters. The multi-objective genetic algorithm was used to realize the multi-objective parametric optimization. The optimization results show that after topological optimization, the mass of the face gear body is reduced by 35.34%, that the maximum equivalent stress decreases by 15.44% and that the maximum axial displacement of the face gear rim decreases by 29.19%. The traveling wave resonance analysis indicates that no-nodal diameter resonance points are within the working rotational speed range of the face gear body, significantly enhancing its strength and axial stiffness.