Patent ID: 7608008

Claim:
An eight-speed powertrain of an automatic transmission for a vehicle comprising: a first shift portion comprising first and second planetary gear sets, an input path to which power directly is input from an input shaft, and an intermediate output path outputting the power by decelerating; and a second shift portion comprising third and fourth planetary gear set, a first intermediate input path receiving the power through the intermediate output path of the first shift portion, a second intermediate input path which the power is variably input from the input shaft, and a final output path configured to shift and output the power input through the first and the second intermediate input path; wherein: the first planetary gear set comprises a single pinion planetary gear set comprising a first sun gear, a first ring gear, and a first planet carrier; the second planetary gear set comprises a single pinion planetary gear set comprising a second sun gear, a second ring gear, and a second planet carrier; the third planetary gear set comprises a single pinion planetary gear set comprising a third sun gear, a third ring gear, and a third planet carrier; and the fourth planetary gear set comprises a single pinion planetary gear set comprising a fourth sun gear, a fourth ring gear, and a fourth planet carrier; and wherein: the third ring gear and the fourth planet carrier are directly connected; the third ring gear is selectively connected to the input shaft through a first clutch, the first sun gear is selectively connected to the first planetary carrier through a second clutch, the fourth sun gear is selectively connected to the third sun gear through a third clutch, the first planetary carrier is selectively connected to a transmission housing through a first brake the third sun gear is selectively connected to the transmission housing through a second brake, the first sun gear is selectively connected to the transmission housing through a third brake, and the fourth planetary carrier is selectively connected to the transmission housing through a fourth brake.