| 摘要 |
An 8-speed power train of an automatic transmission is provided to improve a speed shifting feeling by realizing eight forward speeds and one backward speed using a pair of Ravigneaux gear sets. A first Ravigneaux planetary gear set(DPG1) includes first and second linear gears(S1,S2), first to third planetary carriers(PC1-PC3), and first and second ring gears(R1,R2). The first linear gear is connected to a case through a third brake. The first planetary carrier is gear-coupled with the second linear gear and connected to an input shaft through a second clutch. The first and second ring gears are connected to the case through a fourth brake. A second Ravigneaux planetary gear set(DPG2) includes third and fourth linear gears(S3,S4), fourth to sixth planetary carriers(PC4-PC6), and third and fourth ring gears(R3,R4). The third linear gear is connected to the case through a fourth brake. The fourth planetary carrier is gear-coupled with the fourth linear gear and connected to the input shaft through a third clutch. The fifth and sixth planetary carriers are integrated to be gear-coupled with the third linear gear and the fourth planetary carrier, respectively. The third and fourth ring gears are gear-coupled with the fifth and sixth planetary carriers and directly coupled with an output shaft.
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