Patent ID: 9702440
Date: 2017-07-11
CPC Classifications: F16H

Claim:
1. A powertrain for an automatic transmission consisting of an input shaft, an output shaft, and first to third planetary gear sets, the powertrain comprising: first to seventh actuating elements constituting the first to third planetary gear sets; and shifting elements comprising first to fourth clutches and first and second brakes, wherein at least two of the shifting elements are actuated so that the first to seventh actuating elements are driven or restrained, thereby realizing eight forward speed and two reverse speed ratios, wherein: the first planetary gear set comprises the first actuating element connected to the transmission case to act as a fixed element in a state in which rotation thereof is restrained, the second actuating element connected to the input shaft to act as an equivalent input element, and the third actuating element acting as a transfer output element in a state of outputting an increased gear ratio through fixed action of the first actuating element; and the second and third planetary gear sets comprise the fourth actuating element variably connected to the input shaft through the first clutch while being variably connected to the third actuating element through the second clutch, the fifth actuating element variably connected to the input shaft through the third clutch while being variably connected to the transmission case through the second brake so that rotation of the fifth actuating element is restrained, the sixth actuating element connected to the output shaft, and the seventh actuating element variably connected to the third actuating element through the fourth clutch while being variably connected to the transmission case through the first brake so that rotation of the seventh actuating element is restrained.