US Patent 7247119 Multi-speed planetary power transmission

A power transmission for use in a powertrain has an input shaft, an output shaft, an input planetary gearset, and an output planetary gearset. The planetary gearsets are controlled through the selective engagement of seven torque-transmitting mechanisms, three of which are rotating-type torque-transmitting mechanisms and four of which are stationary-type torque-transmitting mechanisms. By selective engagement of the torque-transmitting mechanisms in combinations of three, the input planetary gearset and the output planetary gearset are combined to establish eight forward speed ratios between the input shaft and the output shaft.