Kinematic Operating Modes of Two-Speed Two-Carrier Planetary Gear Trains with Four External Shafts

Two-speed planetary gear trains with four external shafts, composed of two simple planetary gear trains, are considered in this paper.The labelling system of these trains is defined and all possible variants are determined.Planetary gear trains are divided into three different design groups, and characteristics of trains of each group are given.Possible power flows through the train at both gears for every group are described.An example of determining the function of transmission ratios of two-speed planetary gear trains by means of the torque method is shown.By research of kinematic schemes (design concepts) all train variants which can be created with an input and an output shaft on opposite sides of the train are identified, as well as those train variants where the aforementioned is not possible and their power input has to be placed between the brakes.All train variants where ideal torque ratios influence a change in the operating mode within the same gear are identified.A review of kinematic operating modes (reduction, multiplication, rotational direction of the output in relation to the input shaft) of all possible variants of the considered trains is given.