Planetary gear transmission system has been widely used in the field of aerospace equipment, automobiles, ships, etc. High power density design is an important development direction for transmission machinery, but there is a lack of systematic and deepening research in planetary gear transmission system field. Taken the most widely used 2K–H-type planetary gear transmission system as research object, a design method of high power density considering volume and efficiency is put forward. First, the transmission efficiency model of 2K–H-type planetary gear transmission system is built on the basis of calculation of single gear pair meshing efficiency instead of the look-up table method. Second, the volume model of 2K–H-type planetary gear transmission system is built according to the structure of gear. Finally, the smallest volume and the minimum power loss of 2K–H-type planetary gear transmission system are the target of optimization, and the linear-weighted combination method is used to construct target function. Taken a 2K–H-type planetary gear reducer in some machine tool as an example, the optimization is carried out. The results show that the power loss of optimized system is reduced by 11.42%, and the volume of system is reduced by 25.2%.
