Power transmission system of hybrid electric vehicle

摘要

A power transmission system of a hybrid electric vehicle may include an input and output shaft. A first planetary gear set disposed on the input shaft 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 input shaft. A second planetary gear set includes a fourth rotation element connected to a second motor/generator, a fifth rotation element connected to the second rotation element and the output shaft, and a sixth rotation element connected to the first rotation element. A direct-coupling device connects two rotation elements of the second planetary gear set, and transfer gears connect two rotation elements of the first planetary gear set with the two rotation elements of the second planetary gear set. Friction elements connect a selected rotation element to a transfer gear or to the transmission housing.

主权项

1. A power transmission system of a hybrid vehicle, comprising:
an input shaft receiving torque of an engine; an output shaft disposed in parallel with the input shaft; a first planetary gear set disposed on the input shaft, and including a first rotation element connected to a first motor/generator, a second rotation element operated as an output element, and a third rotation element directly connected to the input shaft; a second planetary gear set disposed on the output shaft, and including a fourth rotation element connected to a second motor/generator, a fifth rotation element directly connected to the second rotation element through a first transfer gear set and connected to the output shaft, and a sixth rotation element selectively connected to the first rotation element through a second transfer gear set and selectively connected to a transmission housing; a direct-coupling device connecting two rotation elements among three rotation elements of the second planetary gear set; the first and second transfer gear sets connecting two rotation elements of the first planetary gear set with two rotation elements of the second planetary gear set, respectively; and friction elements selectively connecting a first selected rotation element among the rotation elements of the first planetary gear set and the second planetary gear set to the second transfer gear set or selectively connecting a second selected rotation element among the rotation elements of the second planetary gear set to the transmission housing.