Patent ID: 8088032

Claim:
A multi-step transmission in planetary design for a motor vehicle, the transmission comprising: a drive input shaft ( 1 ) and an output shaft ( 2 ); first, second, third and fourth planetary gear sets (P 1 , P 2 , P 3 , P 4 ) being arranged in a housing (G) of the transmission, each of the first planetary gear set (P 1 ), the second planetary gear set (P 2 ), the third planetary gear set (P 3 ) and the fourth planetary gear set (P 4 ) having a sun gear, a carrier and a ring gear; at least third, fourth, fifth, sixth, seventh and eighth rotatable shafts ( 3 , 4 , 5 , 6 , 7 , 8 ); six shifting elements ( 03 , 04 , 05 , 14 , 17 , 48 ) comprising first, second and third brakes ( 04 , 03 , 05 ) and first, second, and third clutches ( 48 , 14 , 17 ) and selective engagement of the six shifting elements ( 03 , 04 , 05 , 14 , 17 , 48 ) achieves different gear ratios, between the input shaft ( 1 ) and the output shaft ( 2 ), such that nine forward gears and one reverse gear can be implemented; the sun gear of the first planetary gear set (P 1 ) is coupled to the eighth shaft ( 8 ) and the eighth shaft ( 8 ) is connectable, via the first clutch ( 48 ), to the fourth shaft ( 4 ), the fourth shaft ( 4 ) is coupled to the sun gear of the fourth planetary gear set (P 4 ) and is connectable, via the second clutch ( 14 ), to the input shaft ( 1 ), and, via the first brake ( 04 ), to the housing (G) of the transmission; the ring gear of the first planetary gear set (P 1 ) is coupled to the input shaft ( 1 ), and the input shaft ( 1 ) is connectable, via the third clutch ( 17 ), to the seventh shaft ( 7 ), which is coupled to the carrier of the third planetary gear set (P 3 ) and the carrier of the second planetary gear set (P 2 ); the carrier of the first planetary gear set (P 1 ) is coupled to the sixth shaft ( 6 ), and the sixth shaft ( 6 ) is coupled to a component that couples the ring gear of the fourth planetary gear set (P 4 ) and the sun gear of the third planetary gear set (P 3 ); the carrier of the fourth planetary gear set (P 4 ) is coupled to the third shaft ( 3 ), and third shaft ( 3 ) is connectable, via the second brake ( 03 ) to the housing (G) of the transmission; the sun gear of the second planetary gear set (P 2 ) is coupled to the fifth shaft ( 5 ), and the fifth shaft ( 5 ) is connectable, via the third brake ( 05 ), to the housing (G) of the transmission; and the output shaft ( 2 ) is coupled to the ring gear of the third planetary gear set (P 3 ) and the ring gear of the second planetary gear set (P 2 ).