Patent ID: 7485067
Filing Date: 2009-02-03
Classification: F16H

Abstract:
1. A power train for an automatic transmission, comprising: a first planetary gear set having operational elements of a first sun gear, a first ring gear, and a first planet carrier; a second planetary gear set having operational elements of a second sun gear, a second ring gear, and a second planet carrier; a third planetary gear set having operational elements of a third sun gear, a third ring gear, and a third planet carrier; an input shaft; an output gear; and a transmission case, wherein the second planet carrier is fixedly connected to the third ring gear, the third planet carrier is fixedly connected to the second ring gear, the first sun gear is always stationary by being fixedly connected to the transmission case, the first ring gear always acts as an input element by being fixedly connected to the input shaft, at least one of the fixedly connected third planet carrier and the second ring gear always acts as an output element by being fixedly connected to the output gear, the second sun gear is variably connected to the first ring gear via a first clutch, the third sun gear is variably connected to the first planet carrier via a second clutch, the second sun gear is variably connected to the first planet carrier via a third clutch, the second planet carrier is variably connected to the first ring gear via a fourth clutch, the second planet carrier is variably connected to the transmission case via a first brake and is subjected to a stopping operation of the first brake, and the third sun gear is variably connected to the transmission case via a second brake and is subjected to a stopping operation of the second brake.