Patent ID: 9587712
Date: 2017-03-07
CPC Classifications: F16H

Claim:
1. A planetary gear train of an automatic transmission for vehicles, the planetary gear train comprising: an input shaft receiving power of an engine; an output shaft outputting shifted power of the engine; a first planetary gear set having a first sun gear, a first planetary carrier, and a first ring gear; a second planetary gear set having a second sun gear, a second planetary carrier, and a second ring gear; a third planetary gear set having a third sun gear, a third planetary carrier, and a third ring gear; a fourth planetary gear set having a fourth sun gear, a fourth planetary carrier, and a fourth ring gear; a first rotational shaft including the first sun gear; a second rotational shaft including the first planetary carrier, the second ring gear, the third sun gear, and the fourth sun gear; a third rotational shaft including the first ring gear; a fourth rotational shaft including the second sun gear, and selectively connected to the first rotational shaft and selectively connected to a transmission housing simultaneously; a fifth rotational shaft including the second planetary carrier, and selectively connected to the first rotational shaft and directly connected to the input shaft simultaneously; a sixth rotational shaft including the third planetary carrier and the fourth ring gear and selectively connected to the transmission housing; a seventh rotational shaft including the third ring gear and selectively connected to the first and third rotational shafts; an eighth rotational shaft including the fourth planetary carrier and directly connected to the output shaft; and six frictional elements configured between the rotational shafts and at portions that selectively connect the rotational shafts and the transmission housing to each other.