Patent ID: 7549943

Claim:
A multi-speed automatic transmission of a planetary design for a motor vehicle, the transmission comprising: an input shaft ( 1 ) and an output shaft ( 2 ) arranged in a housing (G); first, second and third planetary gearsets (P 1 , P 2 , P 3 ), and 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 and sixth rotatable shafts ( 3 , 4 , 5 , 6 ) as well as at least six shifting elements ( 03 , 04 , 13 , 14 , 34 , 35 , 36 , 56 ), comprising first and second brakes ( 03 , 04 ) and first, second, third and fourth clutches ( 13 , 14 , 34 , 35 , 36 , 56 ), whose selective engagement creates different gear ratios between the input shaft ( 1 ) and the output shaft ( 2 ) so that at least seven forward gears and one reverse gear can be implemented; wherein the input shaft ( 1 ) is permanently connected to the sun gear of the second planetary gearset (P 2 ), and the input shaft ( 1 ) is detachably connected, via the first clutch ( 13 ), to the third shaft ( 3 ) and, via the second clutch ( 14 ), to the fourth shaft ( 4 ); the output shaft ( 2 ) is permanently connected to the carrier of the second planetary gearset (P 2 ) and to the ring gear of the third planetary gearset (P 3 ); the third shaft ( 3 ) is permanently connected to the carrier of the first planetary gearset (P 1 ), and the third shaft ( 3 ) is detachably connected, via the first brake ( 03 ), to the housing (G) and, via the third clutch ( 36 ), to the sixth shaft ( 6 ); the fourth shaft ( 4 ) is permanently connected to the sun gear of the first planetary gearset (P 1 ), and the fourth shaft ( 4 ) is detachably connected, via the second brake ( 04 ), to the housing (G); the fifth shaft ( 5 ) is permanently connected to the ring gear of the first planetary gearset (P 1 ) and to the carrier of the third planetary gearset (P 3 ); the sixth shaft ( 6 ) is permanently connected to the ring gear of the second planetary gearset (P 2 ); the sun gear of the third planetary gearset (P 3 ) is connected to the housing (G); and one of: the fifth shaft ( 5 ) is detachably connected, via the fourth clutch ( 56 ), to the sixth shaft ( 6 ), the fifth shaft ( 5 ) is detachably connected, via the fourth clutch ( 35 ), to the third shaft ( 3 ), and the third shaft ( 3 ) is detachably connected, via the fourth clutch ( 34 ), to the fourth shaft ( 4 ).