Patent ID: 8206257

Claim:
A multi-speed planetary transmission for a motor vehicle, the transmission comprising: an input drive 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 within a housing (G), 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 , 15 , 17 , 18 ) comprising first, second and third brakes ( 05 , 04 , 03 ) and first, second, and third clutches ( 15 , 18 , 17 ), and selective engagement of the six shifting elements ( 03 , 04 , 05 , 15 , 17 , 18 ) achieves different gear ratios between the drive shaft ( 1 ) and the output shaft ( 2 ) such that nine forward gears and one reverse gear can be implemented; the second planetary gear set (P 2 ) and the third planetary gear set (P 3 ) comprising a shiftable front-mounted gear set, and the first planetary gear set (P 1 ) and the fourth planetary gear set (P 4 ) comprising a main gear set; the sun gear of the second planetary gear set (P 2 ) is coupled to the fifth shaft ( 5 ), and is connectable, via the first clutch ( 15 ), to the drive shaft ( 1 ), and the fifth shaft ( 5 ) is connectable, via the first brake ( 05 ), to the housing (G) of the transmission; the carrier of the second planetary gear set (P 2 ) and the carrier of the third planetary gear set (P 3 ) are coupled to the fourth shaft ( 4 ), and the fourth shaft ( 4 ) is connectable, via the second brake ( 04 ), to the housing (G) of the transmission; the sun gear of the third planetary gear set (P 3 ) is coupled to the eighth shaft ( 8 ), and the eighth shaft ( 8 ) is connectable, via the second clutch ( 18 ), to the drive shaft ( 1 ); the ring gear of the second planetary gear set (P 2 ) and ring gear of the third planetary gear set (P 3 ) are coupled, via the sixth shaft ( 6 ), to the ring gear of the fourth planetary gear set (P 4 ) and the sun gear of the first planetary gear set (P 1 ); the ring gear of the fourth planetary gear set (P 4 ) is coupled to the sun gear of the first planetary gear set (P 1 ); the sun gear of the fourth planetary gear set (P 4 ) is coupled to the third shaft ( 3 ), and the third shaft ( 3 ) is connectable, via the third brake ( 03 ), to the housing (G) of the transmission; the carrier of the first planetary gear sets (P 1 ) and the carrier of the fourth planetary gear set (P 4 ) are coupled to the seventh shaft, and the seventh shaft ( 7 ) is connectable, via the third clutch ( 17 ), to the drive shaft ( 1 ); and the ring gear of the first planetary gear set (P 1 ) is coupled to the output shaft ( 2 ).