| 摘要 |
The present invention has an object to provide 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, the coaxial positioning of the input portion and the output portion and the size reduction of the automatic transmission altogether. As the solving means, there is provided a gear-operated speed change apparatus for an automatic transmission, which has speed change control means for achieving at least seven forward speeds and one reverse speed by engaging/releasing four clutches C1, C2, C3 and C4 and two brakes B1 and B2 properly. One G1 of three planetary gear sets G1, G2 and G3 is a speed-reducing device for reducing the speed of an input rotation always or a speed-increasing device for increasing the input rotation always. One G3 of the remaining two planetary gear sets is a double sun gear type planetary gear set including a third carrier PC3 having a center member CM positioned between two sun gears S3 and S4 for inputting or outputting a rotation.
|
