Investigation on Transmission Error and Noise Improvement of Two-Stage Planetary Gearset Based on MBD and NVH Analysis

Abstract With the increasing demand for Electric Drive (E-drive) vehicles, the development of planetary gearset (PGS) has been actively pursued. In the development process of a PGS, meticulous considerations must be given not only to the reliability of the system but also to various performance aspects such as downsizing for packaging, noise, vibration, and harshness (NVH), as well as efficiency. In this study, multi-body dynamics and NVH analysis were conducted to improve the NVH performance of two-stage planetary geared E-drive reducer systems. The analysis explores the interplay between transmission error (TE) and NVH, with a comprehensive discussion based on the analysis results. The analysis results were validated by comparing them with the test results. While TE has been extensively researched as a primary excitation source in reducers or transmission systems, the relationship between TE in PGS and NVH, especially at the system level, was inadequately studied. Furthermore, experimentally validated studies were rarely conducted on the TE of planetary gearsets. In this study, overall transmission error (OTE), individual gear meshing TE, and noise and vibration response of modal correlated two-stage PGS model were analyzed. The analysis results illustrate how TE manifests in the noise and vibration response. Additionally, gear microgeometry modification cases were suggested as NVH improvement strategies, and their effects have been analytically investigated. In conclusion, overall simulation and investigation works have given instrumental insights into the design and improvement of NVH performances across various PGS systems.