Patent ID: 8231501

Claim:
A multi step transmission of a planetary design for an automatic transmission for a motor vehicle, the multi-step transmission comprising: a drive shaft ( 1 ); an output shaft ( 2 ); first, second, third and fourth planetary gear sets (P 1 , P 2 , P 3 , P 4 ) which are arranged within a transmission housing (G); and a rotatable third shaft ( 3 ), a rotatable fourth shaft ( 4 ), a rotatable fifth shaft ( 5 ), a rotatable sixth shaft ( 6 ), a rotatable seventh shaft ( 7 ) and a rotatable eighth shaft ( 8 ) as well as at least six shift elements ( 03 , 04 , 13 , 17 , 35 , 36 , 58 ) comprising first and second brakes ( 03 , 04 ) and first, second, third and fourth clutches ( 13 , 17 , 35 , 36 , 58 ) whose selective engagement produces different transmission ratios, between the drive shaft ( 1 ) and the output shaft ( 2 ), so that nine forward gears and a reverse gear can be achieved; wherein a sun gear of the first planetary gear set (P 1 ) is connected to the drive shaft ( 1 ); a carrier of the first planetary gear set (P 1 ) is connected to the third shaft ( 3 ) which is connectable to the transmission housing (G) via the first brake ( 03 ), the third shaft ( 3 ) is detachably connectable, via the second clutch ( 35 ), to the fifth shaft ( 5 ) which is permanently connected to a ring gear of the second planetary gear set (P 2 ) and a sun gear of the fourth planetary gear set (P 4 ), and the fifth shaft ( 5 ) is detachably connectable, via the fourth clutch ( 58 ), to the eighth shaft ( 8 ) which is connected to a sun gear of the third planetary gear set (P 3 ); the drive shaft ( 1 ) is detachably connectable to the seventh shaft ( 7 ) which is connected to a carrier of the fourth planetary gear set (P 4 ) via the third clutch ( 17 ); the sixth shaft ( 6 ) is connected to a ring gear of the first planetary gear set (P 1 ) and a carrier of the second planetary gear set (P 2 ); a sun gear of the second planetary gear set (P 2 ) is connected to the fourth shaft ( 4 ) which is connectable with the transmission housing (G) via the second brake ( 04 ); a ring gear of the third planetary gear set (P 3 ) is connected with the transmission housing (G); the output shaft ( 2 ) is connected to a carrier of the third planetary gear set (P 3 ) and a ring gear of the fourth planetary gear set (P 4 ); and the first planetary gear set (P 1 ) is blockable by engagement of the first clutch ( 13 , 36 ) such that, when blocked, the sun gear, the planet carrier and the ring gear of the first planetary gear set (P 1 ) all rotate together in unison with one another.