| 摘要 |
A power train of an automatic transmission for a vehicle includes a fluid torque converter receiving power from the engine and a first brake for locking a second ring gear of a first speed changing part so that the output of a second sun gear receiving power from a turbine of the torque converter becomes the first forward speed. A second clutch is provided for transmitting power of a stator in the torque converter to a transfer drive gear in addition to the first speed level so that the speed is automatically and continuously changed form the time that power of the torque converter is reduced since the power of the torque converter is transmitted to the stator. A first clutch is provided for performing the fixing mode of the second speed level such that the output power of the first speed changing part is the same as the input power of the engine, because the output of the engine is directly transmitted to the first ring gear of the first speed changing part through the first clutch. A third brake locks a third ring gear so that the third ring gear functions as a reaction element in order to output the reduced speed at the mode of the first speed level, the mode of continuous speed changing and the fixing mode of second speed, respectively. A third clutch connects the first speed changing part with the second speed changing part in order to output the third speed level. The automatic transmission is capable of increasing the fuel ratio and its capacity by maximizing the efficiency of the power transmission and being simple in its construction. |
