Abstract
Key words
planetary gearbox, kinematic scheme, methodology, software
Abstract
Combat vehicles are fitted with planetary gear boxes with four-degree of freedom. The basic problem of an initial development of the mentioned gear boxes is to create kinematic schemes that can meet the requirements such as a gearbox size and gear ratios, design realization possibilities, their dimensions and efficiency. Since mathematical synthesis methods of the kinematic schemes in compound planetary gear trains haven’t been designed for a gearbox with four degree of freedom, nor do the existing methods include the design criteria, there is a methodology for composing a gearbox kinematic scheme with a set of simple gear trains (a two-set or the Ravigneaux and a single-set). Design limits for the number of gear’s teeth have been defined from the aspect of the least possible shaft diameter and the maximum gearbox dimensions. The software has been designed to enable the use of methodology and its automation. The software makes possible the creation of kinematic scheme set for complex gear trains which meet the defined criteria, analysis of efficiency level and planetary gear relative speed, as well as the power flow of the gear elements. Number of teeth is to be defined for each kinematic scheme in order to meet the design limits and mounting conditions of a gearbox. The use of flexible software structure and analysis of the gear trains characteristics through the functional modules, make possible the analysis of characteristics of each planetary gear train which can be reduced to the functional modules.