摘要 |
A power transmission system of a hybrid electric vehicle may include a first shaft and a second shaft. A first planetary gear set includes a first rotation element connected to a first motor/generator, a second rotation element operated as an output element, and a third rotation element connected to the first shaft. A second planetary gear set includes a fourth rotation element connected to the third rotation element and a second motor/generator, a fifth rotation element connected to the second rotation element and an output gear, and a sixth rotation element connected to a transmission housing. A direct-coupling device connects two rotation elements among the fourth, fifth, and sixth rotation elements of the second planetary gear set. Transfer gears form the externally-meshing gears, and friction elements connect a selected rotation element to a selected transfer gear or to the transmission housing. |