Influence of Pitting on Total Transmission Error of a Planetary Gear Stage

A big advantage of planetary gear stages is their increased power density compared to gearboxes with helical gear stages of the same gear ratio. Due to the rotating planet shafts measurements on the separate gear meshes are connected with great effort. Measurement results for the transmission error of a single gear stage, e.g. the transmission error of the stage sun-planet, are usually not available. Hence it is more common to measure the total transmission error of the planetary stage.Pitting on the flanks of gear wheels is one mechanism of gear failure. Since pitting increases during running time, they do not lead to an instant failure. Hence the characteristic of transmission error is worsening during running time. It is challenging to investigate condition monitoring for planetary gear stages by using the total transmission error. Therefore, the influence of pitting on the total transmission error is analysed by simulation in a first step.At FZG there is a simulation tool called RIKOR3D, which is capable of doing a quasi-static analysis of a whole gearbox including planetary gear stages. A result of this quasi-static analysis of a planetary gear stage is the total transmission error between input and output.