Evaluation of compound planetary gear set loads by multibody dynamic approach with help of Adams/Gear AT

Planetary gear systems, commonly used in automotive applications for their compact size and high reduction ratios, comprise four key components: a sun gear, planet gears, an internal annulus (or ring) gear, and a carrier. However, for compound planetaries, comprising meshed planets, the high torques generated within these gear trains can create substantial gear forces, which are then transmitted to the gear bearings. This can lead to premature failure of either the bearings or the gear teeth themselves. Therefore, accurately evaluating these loads under various operating conditions are essential for ensuring the gear train's reliability and preventing such failures. Accurate force analysis is crucial for optimizing overall gear system performance. This includes analyzing gear tooth forces, system torques and bearing loads. However, incorporating both micro and macro gear parameters into analytical calculations is extremely complex. Multibody dynamics simulation offers a powerful and effective alternative for analyzing these intricate gear systems. This paper presents an effective approach for analyzing compound meshed planet planetary gear systems using multibody dynamics simulation. Specifically, the Adams Gear-AT tool is used to create a 3D parametric model of the planetary gear system. A key advantage of Gear-AT is its ability to generate detailed gear profiles based on both micro and macro geometry parameters. The paper also includes a brief comparison between the Adams Gear-AT module and other software tools in terms of capabilities , advantages , limitations and applicability. This study investigates the influence of various gear tooth parameters, including addendum and dedendum factors, and profile modification factor, on both gear forces and contact pressures. This analysis aims to optimize gear design in the early stages of development. By performing multibody dynamics (MBD) simulations of the planetary gear system with varying micro and macro geometry parameters, accurate load predictions can be evaluated. This approach facilitates improved gear design and significantly reduces the costs associated with product development, prototyping and physical testing.