Eight, nine and ten speed automatic transmissions

摘要

An automatic transmission includes four planetary gear sets, a plurality of friction and synchronizing clutches and two drive assemblies. Input torque is provided to four clutches which selectively provide torque to various elements of the first and second planetary gear assemblies. Similarly, various elements of the first and second planetary gear assemblies provide power to the two drive assemblies which may either be chain drive or gear assemblies. The outputs of the drive assemblies drive sun gears of the third and fourth planetary gear assemblies. The transmission output is connected to and driven by the planet carriers of the third and fourth planetary assemblies. Sequenced operation of the friction and synchronizing clutches provides eight, nine or ten forward speeds or gear ratios.