Patent ID: 8113983

Claim:
A multi-step automatic transmission of planetary structure for a motor vehicle, the transmission comprising: a drive input shaft ( 1 ) and a drive output shaft ( 2 ) being arranged in a transmission housing (G); first, second and third planetary gearsets (P 1 , P 2 , P 3 ), each of the first, the second and the third planetary gearsets (P 1 , P 2 , P 3 ) comprising a sun gear, a carrier and a ring gear; at least third, fourth, fifth, sixth, and seven rotary shafts ( 3 , 4 , 5 , 6 , 7 ); six shift elements ( 03 , 04 , 05 , 15 , 36 , 57 ) comprising first, second, and third brakes ( 03 , 04 , 05 ) and first, second, and third clutches ( 15 , 36 , 57 ) whose selective engagement produces various transmission ratios between the drive input shaft ( 1 ) and the drive output shaft ( 2 ) such that seven forward gears and one reverse gear can be implemented; the drive input shaft ( 1 ) being integrally coupled to the sun gear of the second planetary gearset (P 2 ) and being connectable, via the first clutch ( 15 ), to the fifth shaft ( 5 ); the drive output shaft ( 2 ) being integrally coupled to the ring gear of the third planetary gearset (P 3 ); the third shaft ( 3 ) being integrally coupled to the carrier of the first planetary gearset (P 1 ) and being connectable, via the first brake ( 03 ), to the transmission housing (G); the fourth shaft ( 4 ) being integrally coupled to the sun gear of the first planetary gearset (P 1 ) and is connectable, via the second brake ( 04 ), to the transmission housing (G); the fifth shaft ( 5 ) being integrally coupled to the carrier of the third planetary gearset (P 3 ), being connectable, via the third brake ( 05 ) to the transmission housing (G), and, via the third clutch ( 57 ), to the seventh shaft ( 7 ); the sixth shaft ( 6 ) being integrally coupled to the sun gear of the third planetary gearset (P 3 ) and the ring gear of the second planetary gearset (P 2 ) and being connectable, via the second clutch ( 36 ), to the third shaft ( 3 ); and the seventh shaft ( 7 ) being integrally coupled to the carrier of the second planetary gearset (P 2 ) and the ring gear of the first planetary gearset (P 1 ).