US Patent 10428912 Transmission for vehicle

A transmission for a vehicle capable is provided to improve fuel efficiency through multiple gear shift stages and enhance power performance of an engine. By combining first and second planetary gear sets, a compound planetary gear set, and multiple frictional elements selectively connecting rotary components of the three planetary gear sets via a corresponding shaft, the transmission provides eleven forward gear stages and three reverse gear stages. In particular, a first rotary element of the first planetary gear is fixedly connected to a transmission case, a second rotary element of the first planetary gear is fixedly connected to a second rotary element of the second planetary gear, and a third rotary element of the first planetary gear device is selectively connected to a first rotary element of the compound planetary gear set and a fourth rotary element of the compound planetary gear set.