Analysis of the stress state in the harmonic drive generator-flexspline system in relation to selected structural parameters and manufacturing deviations

In the paper, the problem of failure of the elastic bearing supporting the generator in a harmonic drive is presented. To analyse the cause of the failure, material investigations as well as simulations of the stress state in the bearing versus manufacturing deviations and fits between the bearing and the generator cam have been carried out. Studies on the stress state in the flexpline have also been conducted in dependence of such technological deviations and generator bearing-flexspline fits for the classical, short, and ultra-short version of the harmonic drive with different heights of the bottom. The simulations have been realised on a mathematical model based on analytical relationships and a 3D model with the aid of FEM.