| 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 comprises: an input shaft receiving power of an engine; an output shaft outputting shifted power; a first planetary gear set including a first sun gear, a first planetary carrier and a first ring gear; a second planetary gear set including a second sun gear, a second planetary carrier and a second ring gear; a third planetary gear set including a third sun gear, a third planetary carrier and a third ring gear; a fourth planetary gear set including a fourth sun gear, a fourth planetary carrier and a fourth ring gear; a first rotary shaft including the first sun gear and selectively connected to a transmission housing; a second rotary shaft including the first planetary carrier and directly connected to the input shaft; a third rotary shaft including the first ring gear, the second planetary carrier, the third sun gear and the fourth sun gear; a fourth rotary shaft including the second sun gear; a fifth rotary shaft including the second ring gear and selectively connected to the first rotary shaft or the second rotary shaft; a sixth rotary shaft including the fourth planetary carrier and directly connected to the output shaft; a seventh rotary shaft including the third planetary carrier and the fourth ring gear and selectively connected to the transmission housing; an eighth rotary shaft including the third ring gear and selectively connected to the fourth rotary shaft and the fifth rotary shaft; and six friction elements included in parts where one rotary shaft is selectively connected to another rotary shaft or the transmission housing. |
