Patent ID: 7566283

Claim:
A multi-speed transmission of a planetary construction for an automatic transmission of 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 ( 3 , 4 , 5 , 6 , 7 ) as well as at least six shifting elements ( 03 , 04 , 05 , 15 , 27 , 36 , 67 ), comprising first, second, and third brakes ( 03 , 04 , 05 ) and first, second, and third clutches ( 15 , 27 , 36 , 67 ), whose selective engagement achieves different gear ratios between the input shaft ( 1 ) and the output shaft ( 2 ) so that at least first, second, third, fourth, fifth, sixth, seventh, eighth and ninth forward gears and one reverse gear can be implemented by the transmission; wherein the input shaft ( 1 ) is permanently connected to the carrier of the first planetary set (P 1 ) and the sun gear of the second planetary set (P 2 ), and detachably connected, via the first clutch ( 15 ), to the fifth shaft ( 5 ); the output shaft ( 2 ) is permanently connected to the ring gear of the fourth planetary set (P 4 ) and detachably connected, via the second clutch ( 27 ), to the seventh shaft ( 7 ); the third shaft ( 3 ) is permanently connected to the ring gear of the second planetary set (P 2 ) and the carrier of the fourth planetary set (P 4 ) and detachably connected, via the first brake ( 03 ), to the housing (G); the fourth shaft ( 4 ) is permanently connected to the ring gear of the third planetary set (P 3 ) and the sun gear of the fourth planetary set (P 4 ), and detachably connected, via the second brake ( 04 ), to the housing (G); the fifth shaft ( 5 ) is permanently connected to the carrier of the third planetary set (P 3 ) and detachably connected, via the third brake ( 05 ), to the housing (G); the sixth shaft ( 6 ) is permanently connected to the ring gear of the first planetary set (P 1 ) and the sun gear of the third planetary set (P 3 ); the seventh shaft ( 7 ) is permanently connected to the carrier of the second planetary set (P 2 ); one of: the third shaft ( 3 ) is detachably connected, via the third clutch ( 36 ), to the six shaft ( 6 ); and the sixth shaft ( 6 ) is detachably connected, via the fourth clutch ( 67 ), to the seventh shaft ( 7 ); and the sun gear of the first planetary set (P 1 ) is fixed to the housing (G).