Mesh Phase Analysis of Encased Differential Gear Train for Coaxial Twin-Rotor Helicopter

Abstract EN

Dynamic excitation caused by time-varying meshing stiffness is one of the most important excitation forms in gear meshing process.

The mesh phase relations between each gear pair are an important factor affecting the meshing stiffness.

In this paper, the mesh phase relations between gear pairs in an encased differential gear train widely used in coaxial twin-rotor helicopters are discussed.

Taking the meshing starting point where the gear tooth enters contact as the reference point, the mesh phase difference between adjacent gear pairs is analyzed and calculated, the system reference gear pair is selected, and the mesh phase difference of each gear pair relative to the system reference gear pair is obtained.

The derivation process takes into account the modification of the teeth, the processing, and assembly of the duplicate gears, which makes the calculation method and conclusion more versatile.

This work lays a foundation for considering the time-varying meshing stiffness in the study of system dynamics, load distribution, and fault diagnosis of compound planetary gears.