Patent ID: 9309951
Filing Date: 2016-04-12
CPC Classification: F16H

Claim Text:
1. A planetary gear train of an auto transmission for a vehicle, comprising: an input shaft into which power of an engine is input; a first planetary gear set including a first sun gear, a first planetary carrier, and a first ring gear; a second planetary gear set including a second sun gear, a second planetary carrier, and a second ring gear; a third planetary gear set including a third sun gear, a third planetary carrier, and a third ring gear; a fourth planetary gear set including a fourth sun gear, a fourth planetary carrier, and a fourth ring gear; a first rotational shaft configured to connect the first and second sun gears and selectively connected to a transmission housing; a second rotational shaft configured to connect the first and third planetary carriers and the fourth ring gear; a third rotational shaft configured to connect the first ring gear and selectively connected to the transmission housing; a fourth rotational shaft configured to connect the second planetary carrier and directly connected to an input shaft; a fifth rotational shaft configured to connect the second ring gear and the third sun gear; a sixth rotational shaft configured to connect the third ring gear; a seventh rotational shaft configured to connect the fourth sun gear, and selectively connected with the input shaft and selectively connected to the fifth and sixth rotational shafts; an eighth rotational shaft configured to connect the fourth planetary carrier and directly connected with an output shaft and selectively connected with the sixth rotational shaft; and six friction elements selectively connecting the rotational shafts and selectively connecting the first and third rotational shafts with the transmission housing.