PLANETARY GEAR TRAIN OF AUTOMATIC TRANSMISSION FOR VEHICLES

摘要

Disclosed is a planetary gear train of an automatic transmission for a vehicle. According to an embodiment of the present invention, the planetary gear train includes: an input shaft receiving power of an engine; an output shaft outputting changed power; a first planetary gear set including three rotating elements; a second planetary gear set including three rotating elements; a third planetary gear set including three rotating elements; and a fourth planetary gear set including three rotating elements. A first rotating element of the first planetary gear set is selectively connected to second and third rotating elements of the third planetary gear set, a second rotating element of the same is directly connected to the input shaft and a third rotating element of the second planetary gear set, and a third rotating element of the same is directly connected to the output shaft. A first rotating element of the second planetary gear set is directly connected to a second rotating element of the third planetary gear set, and a second rotating element of the same is selectively connected to the first and third rotating elements of the third planetary gear set. The first rotating element of the third planetary gear set is directly connected to a first rotating element of the fourth planetary gear set, and the second rotating element of the same is selectively connected to a transmission housing. A second rotating element of the fourth planetary gear set is directly connected to the output shaft, and a third rotating element of the same is selectively connected to the transmission housing. Six frictional elements are formed in the parts in which the rotating elements and the transmission housing are selectively connected.