Classification and synthesis of three-loop planetary gearboxes

Abstract

In the transmissions of trucks, agricultural vehicles and tractors, gear boxes with a planetary divider and/or an additional reductor unit which is depending on the traffic conditions of the machine, reduces the speed of rotation or operates on a direct drive are used. The divider and the additional reductor unit are intended for a stepwise changing of the range of the main 3-speed or 4-speed gearbox, consisting of gears with fixed axles, which makes it possible to increase the number of stages realized 4 times. If the planetary train will work in the differential mode, this will allow additionally increase the number of stages in the combined planetary gearboxes and, accordingly, the number of operating modes of the tractor. Consequently, the main gearbox consists of gears with fixed axes of gears can work either separately in a single-flow mode of operation of the planetary train (reductor or in the direct drive mode) or in a two-flow mode - in parallel with other ordinary gears when the planetary train as a differential. When using two planetary trains operating in the differential mode, the number of parallel power flows increases to three, which makes it possible to further improve the functional and power capabilities of multi-flow gearboxes. The purpose of the study is to analyze gearbox schemes consisting of three sets of gears with fixed gearwheel axes and two differential mechanisms forming three parallel power transmission flows. Classification of possible structural schemes of three-flow transmissions is given, a general expression for calculating the number of stages of a three-flow gearbox is obtained. A technique for the synthesis of kinematic schemes of three-flow planetary gearboxes is described, with the using of which new gearbox schemes are obtained for each possible structure, which are characterized by using simple mechanisms, high efficiency and a small number of control elements.