PLANETARY TRANSMISSIONS WITH THREE GEAR SETS AND A STATIONARY FIXED INTERCONNECTION

摘要

The family of transmissions has a plurality of members that can be utilized in powertrains to provide at least seven forward speed ratios and at least one reverse speed ratio. The transmission family members include three planetary gear sets having six torque-transmitting mechanisms. Two fixed interconnections continuously connect members of the first, second and third planetary gear sets. One of the fixed interconnections is also connected to the transmission housing. The powertrain includes an engine and torque converter that is not continuously connected to any of the planetary gear members and an output member that is continuously connected with one of the planetary gear members. The six torque-transmitting mechanisms provide interconnections between various gear members, the input shaft, the output shaft, and with the transmission housing, and are operated in combinations of three to establish at least seven forward speed ratios and one reverse speed ratio.