| 摘要 |
A 7-speed power train of an automatic transmission is provided to improve a speed shifting feeling by changing one of two operation elements in the automatic transmission during a speed shifting process. A double pinion planetary gear set(DPG) includes a first ring gear(R1), a first planetary carrier(PC1), a second planetary carrier(PC2), and a first sun gear(S1). The first ring gear is directly connected to an output shaft. The first planetary carrier is gear-coupled with the first ring gear and directly connected to a case. The second planetary carrier is gear-coupled with the first ring gear. The first sun gear is gear-coupled with the first and second planetary carriers. A Ravigneaux planetary gear set(RPG) includes a second ring gear(R2), a third ring gear(R3), a third planetary carrier(PC3), a fourth planetary carrier(PC4), and a second sun gear(S2). The second ring gear is connected to the second planetary carrier and the first sun gear through fourth and third clutches, respectively. The third ring gear is connected to the first ring gear through a fifth clutch. The third planetary carrier is gear-coupled with the second ring gear. The fourth planetary carrier is gear-coupled with the first and second ring gears and directly connected to the input shaft. The second sun gear is gear-coupled with the third and fourth planetary carriers and connected to the second ring gear through a sixth clutch. The second sun gear is connected to the first sun gear through a second clutch and coupled with the case through a first clutch.
|
