Planetary gear train of automatic transmission for vehicle

A planetary gear train of an automatic transmission for a vehicle may include an input shaft receiving torque of an engine, an output shaft outputting changed torque of the engine, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first rotation shaft selectively connectable to the input shaft, a second rotation shaft directly connected to the input shaft, a third rotation shaft selectively connectable to a transmission housing, a fourth rotation shaft, a fifth rotation shaft selectively connectable to at least one of the second rotation shaft and the third rotation shaft, a sixth rotation shaft selectively connectable to the first rotation shaft, and directly connected to the output shaft, and a seventh rotation shaft selectively connectable to the transmission housing. 本发明涉及种用于车辆的自动变速器的行星齿轮系，其可以包括：输入轴，其接收发动机的扭矩；输出轴，其输出改变了的发动机的扭矩；第行星齿轮组；第二行星齿轮组；第三行星齿轮组；第四行星齿轮组；第旋转轴，其能够选择性地连接至输入轴；第二旋转轴，其直接地连接至输入轴；第三旋转轴，其能够选择性地连接至变速器壳体；第四旋转轴；第五旋转轴，其能够选择性地连接至第二旋转