Abstract: A gear train may include an input shaft adapted to receive torque of an engine, an output shaft adapted to output changed torque, a first planetary gear set including a first sun gear, a first planet carrier, and a first ring gear as rotation elements thereof, a second planetary gear set including a second sun gear, a second planet carrier, and a second ring gear as rotation elements thereof, and a third planetary gear set including a third sun gear, a third planet carrier, and a third ring gear as rotation elements thereof.

Abstract: A planetary gear train may include an input shaft, an output shaft, a first planetary gear set, a second planetary gear set, a first rotation shaft directly connected to one rotation element of the first planetary gear set and one rotation element of the second planetary gear set, and selectively connected to the input shaft, a second rotation shaft directly connected to another rotation element of the second planetary gear set and directly connected to the output shaft, a third rotation shaft directly connected to another rotation element of the first planetary gear set and the other rotation element of the second planetary gear set, and selectively connected to the input shaft or to a transmission housing, and a fourth rotation shaft directly connected to the other rotation element of the first planetary gear set, and selectively connected to the input shaft through two paths or to the transmission housing.

Abstract: A planetary gear train of an automatic transmission for a vehicle is disclosed. The planetary gear train can achieve ten forward speeds and one reverse speed by combining four planetary gear sets with three clutches and three brakes. Therefore, the planetary gear train can improve power delivery efficiency and fuel economy by achieving multiple shift-speeds of the automatic transmission.