Patent ID: 8328678

Claim:
A gear train of an automatic transmission for vehicles including a first planetary gear set having a first sun gear, a first planet carrier, and a first ring gear as rotation elements thereof, a second planetary gear set having a second sun gear, a second planet carrier, and a second ring gear as rotation elements thereof, a third planetary gear set having a third sun gear, a third planet carrier, and a third ring gear as rotation elements thereof, a fourth planetary gear set having a fourth sun gear, a fourth planet carrier, and a fourth ring gear as rotation elements thereof, and a plurality of friction members, wherein a rotation element of the first planetary gear set is connected to a rotation element of the second planetary gear set through a first power transmitting member, another rotation element of the second planetary gear set is connected to a rotation element of the third planetary gear set through a second power transmitting member, another rotation element of the third planetary gear set is connected to a rotation element of the fourth planetary gear set through a third power transmitting member, and another rotation element of the fourth planetary gear set is connected to another rotation element of the first planetary gear set through a fourth power transmitting member such that eight rotation elements are formed, wherein the eight rotation elements comprises a first rotation element including an input shaft directly connected to the second ring gear, a second rotation element including an output shaft connected to the fourth planet carrier connected to the third ring gear through the third power transmitting member, a third rotation element including the first power transmitting member directly connecting the first and second sun gears, a fourth rotation element including the first ring gear, a fifth rotation element including the second power transmitting member directly connecting the second planet carrier with the third sun gear, a sixth rotation element including the fourth power transmitting member directly connecting the first planet carrier with the fourth ring gear, a seventh rotation element including the third planet carrier, and an eighth rotation element including the fourth sun gear, and wherein the plurality of friction members comprises first, second, third, and fourth clutches selectively connecting the rotation elements with other rotation elements and first and second brakes selectively connecting the rotation elements with a transmission housing.