In the last decade, computer-aided engineering (CAE) tools have become a determinant factor in the analysis of engineering problems. In fact, they bring a clear reduction of time in the design phase of a new product thanks to parametrical studies based on virtual prototypes. The application of such tools to gearboxes allowed engineers to study the efficiency and lubrication inside transmissions. However, the difficulties of handling the computational domain are still a concern for complex system configurations. For this reason, the authors maintain that it is fundamental to introduce time efficient algorithms that enable the effective study of any kind of gear, e.g., helical and bevel configurations. In this work, a new mesh handling strategy specifically suited for this kind of studies is presented. The methodology is based on the Global Remeshing Approach with Mesh Clustering (GRA^MC) process that drastically reduces the simulation time by minimizing the effort for updating the grids. This procedure was tested on spur, helical, and bevel gears, thus demonstrating the flexibility of the approach. The comparison with experimentally measured power losses highlighted the good accuracy of the strategy. The algorithm was implemented in the opensource software OpenFOAM®.

The circular layout and the kinematics of planetary gearboxes result in characteristic oil flow phenomena. The goal of this paper is to apply a new remeshing strategy, based on the finite volume method, on the numerical analysis of a planetary gearbox and its evaluation of results as well as its validation. The numerical results are compared with experimental data acquired on the underlying test rig with high-speed camera recordings. By use of a transparent housing cover, the optical access in the front region of the gearbox is enabled. Different speeds of the planet carrier and immersion depths are considered. A proper domain partitioning and a specifically suited mesh-handling strategy provide a highly efficient numerical model. The open-source software OpenFOAM^® is used.

In the framework of the H2020 project IDERPLANE, aimed at providing innovative, effective, and validated criteria for the design and assessment of more reliable planet bearings for aerospace application analyzing the problem from a damage tolerance perspective, the present paper presents the numerical study and optimization of a test rig specifically designed for the experiments on the full-test article. Specifically, for the first time ever, an entire system including shafts, gears and bearings with all the rolling elements have been studied with a Finite Volume Computational Fluid Dynamics approach. This ambitious challenge was addressed with the implementation of a new mesh handling technique, namely the Global Remeshing Approach with Mesh Clustering (GRAMC). The aim was to optimize the lubrication of the test article to avoid unexpected failures during the experimental campaign. Three different oil jet directions have been studied and the most effective one, namely the axial one, was selected for the final test rig design.

The high compactness of cycloidal gearboxes, their low backlash and their capability to withstand overloads are just some of the factors that have led the research to focus on these solutions for reducing speed. These types of gearboxes have very complex geometries, architectures and dynamics, and the contact between the various components occurs simultaneously in different areas of them. Therefore, numerical simulations can represent an essential tool for the design of these systems. The objective of this study is to understand in what and how numerical simulations can support the design of cycloidal reduction systems and make a review of the literature to understand to date, who, why and how has conducted these of studies. The reviewed contributions, collected through Scopus, are analyzed and classified according to, among others, the component modelled and analyzed, the scope of the analysis and if the analysis has been validated with experimental results. Bibliometric analyses show that the topic is of growing interest to the international scientific community but remains almost an Asian monopoly since most of the results are not shared in English. It has emerged that the study of the contact between cycloidal disk and rollers remains the most widespread study. The research showed that only a small number of analyses have been validated by experimental results.

Foreword The International Conference on Gears in Garching near Munich, Germany, is an established platform for researchers on and manufacturers of gears and transmission systems. At the 10th issue of the conference in September of 2023, gear experts discussed the latest developments and research results from the powertrain industry and academia. Given the increasing challenges of climate change and its impacts, acting in compliance with the UN Sustainable Development Goals is mandatory for all engineers today. Gear engineers must consider these objectives in their research and development activities and provide solutions that meet the technical requirements and contribute to achieving the UN goals. Greenhouse gas (GHG) emission is a primary driver for climate change. Reducing GHG emissions should be an urgent action for the combat against climate change. Therefore, the research on efficiency is assigned a key role. Several contributions in this report discuss the possibilities for further improvement in efficiency from different points of view, like gear design or lubrication. Other subjects of the conferences are Responsible Consumption and Production. H...