A gear-operated speed change apparatus for an automatic transmission, which can
make the degree of freedom for selecting a gear ratio higher than that of the case
using the Ravigneaux type composite planetary gear train, while achieving a strength
advantage of the gear train, an improvement in the fuel economy, coaxial positioning
of the input port and output portions and size reduction of the automatic transmission
altogether. The apparatus can achieve at least seven forward speeds and one reverse
speed by engaging/releasing four clutches and two brakes. One of the three planetary
gear sets can reduce the speed of an input rotation always or increase the input
rotation always. One of the remaining two planetary gear sets is a double sun gear
type planetary gear set including a third carrier having a center member positioned
between two sun gears for inputting or outputting a rotation.
