Patent ID: 7601090

Claim:
A power train of an automatic transmission, comprising: an input shaft; an output gear; a transmission case; a speed shift unit comprising a fixed input member that is fixedly connected to the input shaft, a fixedly stopped member that is fixedly connected to the transmission case, an increased speed output member that outputs an increased rotational speed, and a reduced speed output member that outputs a reduced rotational speed; an output unit comprising a variable input member that is variably connected to the input shaft, the increased speed output member, and the reduced speed output member, a variable input/stopped member that is variably connected to the input shaft or is variably connected to the transmission case, a variably stopped member that is variably connected to the transmission case, and a shift speed output member that acts as an output member by being fixedly connected to the output gear, wherein the output unit generates seven forward speeds and three reverse speeds at the shift speed output member by operations of the variable input member, the variable input/stopped member, and the variably stopped member; a first clutch for variably connecting the variable input member to the reduced speed output member; a second clutch for variably connecting the variable input member to the input shaft; a third clutch for variably connecting the variable input member to the increased speed output member; a fourth clutch for variably connecting the variable input/stopped member to the input shaft; a first brake for variably stopping the variably stopped member; and a second brake for variably stopping the variable input/stopped member.