The bases of angular velocity plans for three-degree-of-freedom planetary automatic transmissions with eight forward gears

The modern automotive strategy aims to decrease fuel consumption and harmful emissions. The best way to do this is to increase the number of stages in gearboxes. The design of planetary gearboxes is based on the synthesis of their kinematic schemes. This is a complex and time-consuming procedure that requires taking into account a large number of options. The resultant kinematic schemes must fully meet kinematic and power requirements of the developers and provide the possibility of their structural implementation. A method for the synthesis of three-degree-of-freedom kinematic planetary gearboxes based on the properties of the angular velocity plan of a complex planetary gear has been developed at Bauman Moscow State Technical University. According to this method, the synthesis of kinematic schemes is carried out in two stages. At the first stage, the basis of the angular velocity plan is constructed. Unlike the angular velocity plan, it contains all operating points with specified transmission ratios but does not have the required number of planetary gear sets and lockup clutches. At the second stage, an additional (so-called auxiliary) link is introduced to ensure the required number of planetary gear sets and lockup clutches. The results of research include the bases of angular velocity plans that can be useful when synthesizing kinematic schemes of planetary gearboxes with eight forward gears providing continuous power flows during changing the gears. Methods for constructing the zero lines of auxiliary links are proposed for each basis of angular velocity plans, which is necessary to develop the angular velocity plans themselves.

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