PLANETARY GEAR TRAIN OF AUTOMATIC TRANSMISSION FOR VEHICLES

摘要

A planetary gear train of an automatic transmission for vehicles may include an input shaft receiving torque of an engine, an output shaft outputting changed torque, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first rotational shaft selectively connected to a transmission housing, a second rotational shaft directly connected to the input shaft, a third rotational shaft, a fourth rotational shaft, a fifth rotational shaft selectively connected to the first rotational shaft or the second rotational shaft, a sixth rotational shaft directly connected to the output shaft, a seventh rotational shaft selectively connected to the transmission housing, an eighth rotational shaft selectively connected to the fourth rotational shaft or the fifth rotational shaft, and six friction elements interposed between the rotational shafts, or between at least one rotational shaft and the transmission housing to connect selectively.

主权项

1. A planetary gear train of an automatic transmission for vehicles, comprising:
an input shaft receiving torque of an engine; an output shaft outputting changed torque; 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, a second ring gear; a third planetary gear set including a third sun gear, a third planetary carrier, a third ring gear; a fourth planetary gear set including a fourth sun gear, a fourth planetary carrier, a fourth ring gear; a first rotational shaft including the first sun gear and selectively connected to a transmission housing; a second rotational shaft including the first planetary carrier and directly connected to the input shaft; a third rotational shaft including the first ring gear, the second planetary carrier, the third sun gear, and the fourth sun gear; a fourth rotational shaft including the second sun gear; a fifth rotational shaft including the second ring gear and selectively connected to the first rotational shaft or the second rotational shaft; a sixth rotational shaft including the fourth planetary carrier and directly connected to the output shaft; a seventh rotational shaft including the third planetary carrier and the fourth ring gear and selectively connected to the transmission housing; an eighth rotational shaft including the third ring gear and selectively connected to the fourth rotational shaft or the fifth rotational shaft; and six friction elements interposed between the rotational shafts, or between at least one rotational shaft and the transmission housing so as to connect selectively.