SEVEN SPEED TRANSMISSION WITH SIX TORQUE-TRANSMITTING MECHANISMS AND THREE PLANETARY GEAR SETS

摘要

A multi-speed transmission is provided that includes three planetary gear sets and seven torque-transmitting mechanisms with various fixed interconnections to provide seven forward speed ratios and one reverse speed ratio. The first planetary gear set is a dual sun planetary and the torque-transmitting mechanism engagement schedule is designed so that, in the reverse speed ratio, a predetermined speed ratio is achieved at the second sun gear member in the dual sun planetary and the input member, and, in the first forward speed ratio, the same magnitude predetermined speed ratio is achieved between the second sun gear member and the input member, but with the second sun gear member rotating in an opposite direction as in the reverse speed ratio.