Patent ID: 7549942

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, third and fourth planetary gear sets (P 1 , P 2 , P 3 , P 4 ), and each of the first, the second, the third and the fourth planetary gear sets (P 1 , P 2 , P 3 , P 4 ) comprising a sun gear, a carrier and a ring gear; at least third, fourth, fifth, sixth and seventh rotatable shafts ( 1 , 2 , 3 , 4 , 5 , 6 , 7 ), as well as at least six control elements ( 03 , 04 , 05 , 15 , 17 , 36 ), comprising first, second, and third brakes ( 03 , 04 , 05 ) and first, second, and third clutches ( 15 , 17 , 36 ), whose selective engagement creates different gear ratios between the input shaft ( 1 ) and the output shaft ( 2 ) so that at least nine forward gears and a reverse gear can be implemented; wherein the input shaft ( 1 ) is permanently connected to the carrier of the first planetary gear set (P 1 ) and detachably connectable, via the first clutch ( 15 ), to the fifth shaft ( 5 ) and, via the second clutch ( 17 ), to the seventh shaft ( 7 ); the output shaft ( 2 ) is permanently connected to the ring gear of the fourth planetary gear set (P 4 ) and the carrier of the second planetary gear set (P 2 ); the third shaft ( 3 ) is permanently connected to the ring gear of the second planetary gear set (P 2 ) and the carrier of the fourth planetary gear set (P 4 ) and detachably connectable, via the first brake ( 03 ), to the housing (G); the fourth shaft ( 4 ) is permanently connected to the ring gear of the third planetary gear set (P 3 ) and the sun gear of the fourth planetary gear set (P 4 ) and detachably connectable, via the second brake ( 04 ), to the housing (G); the fifth shaft ( 5 ) is permanently connected to the carrier of the third planetary gear set (P 3 ) and detachably connectable, via the third brake ( 05 ), to the housing (G); the sixth shaft ( 6 ) is permanently connected to the ring gear of the first planetary gear set (P 1 ) and the sun gear of the third planetary gear set (P 3 ) and detachably connectable, via the third clutch ( 36 ), to the third shaft ( 3 ); the seventh shaft ( 7 ) is permanently connected to the sun gear of the second planetary gear set (P 2 ); and the sun gear of the first planetary gear set (P 1 ) is fixed to the housing (G).