Power transmission system of hybrid electric vehicle

摘要

A power transmission system of a hybrid electric vehicle includes: an input shaft; an output shaft; first, second and third planetary gear sets; a first rotational shaft, a second rotational shaft, a third rotational shaft, a fourth rotational shaft; a fifth rotational shaft; a sixth rotational shaft; and three friction elements mutually selectively connecting rotational shafts to each other or selectively connecting the respective rotational shafts and the transmission housing such that the power transmission system of the hybrid electric vehicle can suppress conversion to an ENG mode by providing sufficient power performance at a time of wide open throttle (WOT) launching and maximally use power of an engine at a time of conversion to a first HEV mode and a third HEV mode.

主权项

1. A power transmission system of a hybrid electric vehicle comprising:
an input shaft into which power of an engine is input; an output shaft outputting transmitted rotational power through an output gear; a first planetary gear set having three rotation elements having a first sun gear, a first planetary carrier, and a first ring gear, wherein the first planetary gear set is disposed on the input shaft; a second planetary gear set having three rotation elements having a second sun gear, a second planetary carrier, and a second ring gear, wherein the second planetary gear is disposed on a coaxial line of the first planetary gear set; a third planetary gear set having three rotation elements having a third sun gear, a third planetary carrier, and a third ring gear, wherein the third planetary gear set is disposed on a coaxial line of the second planetary gear set; a first rotational shaft directly connected with a first motor/generator, while directly connecting one rotation element among the rotation elements of the first planetary gear set and one rotation element among the rotation elements of the second planetary gear set; a second rotational shaft directly connected with the output shaft while directly connecting one rotation element of the first planetary gear set, excepted from the rotation elements connected to the first rotational shaft, and one rotation element among the rotation elements of the third planetary gear set; a third rotational shaft directly connecting one rotation element of the first planetary gear set, excepted from the rotation elements connected to the first or second rotational shaft, and the input shaft; a fourth rotational shaft connected to one rotation element of the second planetary gear set, excepted from the rotation elements connected to the first rotational shaft, to be selectively connected to a transmission housing; a fifth rotational shaft selectively connected to the transmission housing, while directly connecting one rotation element of the second planetary gear set, excepted from the rotation elements connected to the first or fourth rotational shaft, and one rotation element of the third planetary gear set, excepted from the rotation elements connected to the second rotational shaft; a sixth rotational shaft directly connected to one rotation element of the third planetary gear set, excepted from the rotation elements connected to the second or fifth rotational shaft, to be directly connected to a second motor/generator; and three friction elements selectively connecting the first, second, third, fourth, fifth, or sixth rotational shaft to each other or selectively connecting the first, second, third, fourth, fifth, or sixth rotational shaft and the transmission housing.