Patent ID: 7258647

Claim:
A power train of a 7-speed transmission for a vehicle, comprising: an input shaft; a transmission case; a first single-pinion planetary gear set, disposed on the input shaft and including a first ring gear fixedly connected to a second planetary carrier; a second single-pinion planetary gear set, disposed on the input shaft and including a second ring gear fixedly connected to a third planetary carrier; a third single-pinion planetary gear set, disposed on the input shaft and including a third ring gear fixedly connected to a first planetary carrier; a first sun gear selectively connected to the transmission case via a first brake; a second sun gear fixedly connected to the input shaft to always operate as an input element; and a third sun gear selectively connected to the transmission case via a third brake; wherein a first clutch selectively connects the second planetary carrier to the input shaft, a second brake and a one way clutch selectively connect the third planetary carrier to the transmission case, and the third ring gear is connected to an output shaft.