Configuration-2
Abstract：The electric transmission system congfiguration-2 is one of the main electric drives for tracked vehicles．The geometrical model for the powertrain cabin is established and the preliminary design for its cooling system is implemented．The mathematic model is established for therma1 current field computation．simulation and analysis in the power train cabin．The three-dimensional structure of the powertrain cabin is optimized．The validity of the cooling system design is proved．The foundation for optimizing the whole electric transmission system configuration is laid．
Key Words：dynamic and electric engineering；tracked vehicle；electric transmission；modeling；thermal current field；Structure optimization
Introduction
The electric transmission system configuration-2is a main form of the electric drive for tracked vehicles，which is defined against configuration-1．
Configuration-1 consists of two driving motors in both left and right sides of the vehicle body，powered by the engine—generator，while configuration-2 consists of a driving motor and a turning motor，and it is a typical dual—power transmission mechanism. The block diagram of configuration-2 is showed in Fig．1．
There is a power feedback path of cross shaft on the configuration-2，and the inner power can be fed back to the outer when it is turning，so overloading capacity and frequency of the driving motor falls significantly，and the turning capability becomes better．
