Patent ID: 9556936
Date: 2017-01-31
CPC Classifications: F16H

Claim:
1. A planetary gear train of an automatic transmission for a vehicle comprising: an input shaft receiving power of an engine; an output shaft outputting shifted power of the engine; 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 including the first and second sun gears and selectively connected with a transmission housing; a second rotational shaft including the first planetary carrier and the fourth ring gear; a third rotational shaft including the first ring gear and selectively connected with the transmission housing; a fourth rotational shaft including the second planetary carrier and directly connected with the input shaft to be continuously operated as an input element; a fifth rotational shaft including the second ring gear and the third sun gear and selectively connected with the second rotational shaft; a sixth rotational shaft including the third planetary carrier and selectively connected with the second rotational shaft; a seventh rotational shaft including the third ring gear and the fourth planetary carrier and directly connected with the output shaft to be continuously operated as an output element; an eighth rotational shaft including the fourth sun gear, selectively connected with the input shaft, and selectively connected with the sixth rotational shaft; and six frictional elements provided to selectively connect at least two rotational shafts with each other and to selectively connect at least one of the rotational shafts with the transmission housing.