| 摘要 |
A power train of a 7-stage automatic transmission for a vehicle is provided to simplify a total structure and to reduce a manufacturing cost by forming four single planetary gear sets with a combination of three clutches and three brakes. A first shift unit(A) is a first planetary gear set(PG1) formed with a double pinion planetary gear set in order to reduce rotatory power received from an input shaft. A second shift unit(B) is composed of second, third, and fourth planetary gear sets(PG2,PG3,PG4) as single pinion planetary gear sets in order to shift rotatory power received through one input path of the first shift unit and two input paths of the input shaft in a 7-forward and 2-reverse shifting manner. A first, second, and third clutches(C1,C2,C3) are disposed in three input paths in order to control the rotatory power to be applied from the input shaft and the first shift unit to the second shift unit. A first, second, and third brakes(B1,B2,B3) are connected selectively with a transmission housing in order to operate three operational elements of the second shift unit as selective fixing elements. |
