| 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 of an automatic transmission for a vehicle of the present invention comprises: an input shaft for receiving the power of the engine; a first planetary gear set which has a first sun gear, a first planetary carrier, and a first ring gear; a second planetary gear set which has a second sun gear, a second planetary carrier, and a second ring gear; a third planetary gear set which has a third sun gear, a third planetary carrier, and a third ring gear; a fourth planetary gear set which has a fourth sun gear, a fourth planetary carrier, and a fourth ring gear; a first rotary shaft which comprises the first sun gear and the second sun gear and is selectively connected to the transmission housing; a second rotary shaft which comprises the first planetary carrier, the third planetary carrier, and the fourth ring gear; a third rotary shaft which comprises the first ring gear and is selectively connected to the transmission housing; a fourth rotary shaft which comprises the second planetary carrier and is directly connected to the input shaft; a fifth rotary shaft which comprises the second ring gear, and the third sun gear; a sixth rotary shaft which comprises the third ring gear; a seventh rotary shaft which comprises the fourth sun gear and is selectively connected to the input shaft and is simultaneously selectively connected to the fifth rotary shaft and the sixth rotary shaft; an eighth rotary shaft which comprises the fourth planetary carrier and is directly connected to the output shaft and is simultaneously selectively connected to the sixth rotary shaft; and six friction elements for selectively connecting the rotary shaft to the rotary shaft and the rotary shaft and the transmission housing. |
