PLANETARY GEAR TRAIN OF AUTOMATIC TRANSMISSION FOR VEHICLE

PROBLEM TO BE SOLVED: To provide a planetary gear train of an automatic transmission for vehicle, the gear train achieving gear shift of 8 forward speeds and 2 reverse speeds, by combining a plurality of planetary gear sets with a plurality of friction members.SOLUTION: A planetary gear train includes: an input shaft having a rotation power of an engine transmitted thereto; an output gear to output the rotation power changed; a composite planetary gear set formed with combination of first and second planetary gear sets and having a first sun gear, a second sun gear, a common planetary carrier, and a common ring gear as rotating members; first to seventh rotating members comprising a third planetary gear set having a third sun gear, a third planetary carrier, and a third planetary gear set as the rotating members thereof, and each rotating member of the composite planetary gear set and the third planetary gear set; and a friction member comprising a clutch for selectively coupling the rotating member and a brake for selectively coupling the rotating member with a transmission housing.