POWER TRAIN OF AUTOMATIC TRANSMISSION

摘要

The purpose of the present invention is to provide a power train of an automatic transmission enabled to have nine forward stages and one reverse stage by constructing seven rotating elements using two planetary gear sets and selectively engaging three rotating elements using four clutches and three brakes. To this end, a power train of an automatic transmission according to the present invention comprises: a first planetary gear set (100) comprising three rotating elements that are continuously and rotatably connected, and configured such that a first rotating element (110) at an outer side is always connected to an input shaft (IN), and a second rotating element (120) and a third rotating element (130) are regulated by brakes (B1 and B2) and clutches (C1 and C2), respectively; and a second planetary gear set (200) comprising first to fourth rotating elements (210-240) that are rotatably connected wherein the first rotating element (210) at an outer side is connected to the input shaft (IN) via a clutch (C3), the second rotating element (220) is always connected to an output shaft (OUT), the third rotating element (230) is regulated by a brake (B3) and a clutch (C4), and the fourth rotating element (240) is connected to the first planetary gear set (100) by interposing the clutches (C1 and C2). Particularly, the first planetary gear set (100) comprises a single- or double-pinion planetary gear. Furthermore, the second planetary gear set (200) comprises a Ravigneaux planetary gear, a Simpson planetary gear, two simple planet gears or laminated planet gears in which two planet gears are assembled.