Patent ID: 8414446

Claim:
A multi-stage transmission comprising: a housing ( 9 ); a drive shaft (AN); an output shaft (AB); first, second, third and fourth planetary gear sets (RS 1 , RS 2 , RS 3 , RS 4 ), and each of the first, the second, the third and the fourth planetary gear sets (RS 1 , RS 2 , RS 3 , RS 4 ) comprising a first element, a second element and a third element, at least first, second, third, fourth, fifth, sixth, seventh and eighth rotatable shafts ( 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ) six shift elements comprising first, second, third and fourth clutches (K 1 , K 2 , K 3 , K 4 ) and first and second brakes (B 1 , B 2 ), and selective engagement of the first clutch (K 1 ), the second clutch (K 2 ), the third clutch (K 3 ), the fourth clutch (K 4 ), the first brake (B 1 ) and the second brake (B 2 ) results in different transmission ratios between the drive shaft (AN) and the output shaft (AB) such that up to nine forward gears can be implemented; wherein the drive shaft (AN) forms the first shaft ( 1 ) and is connectable, via the first clutch (K 1 ), to the third element (H 1 ) of the first planetary gear set (RS 1 ); the first element (SO 1 ) of the first planetary gear set (RS 1 ) is rotationally fixed to the housing; the second element (ST 1 ) of the first planetary gear set (RS 1 ) is coupled, via the sixth shaft ( 6 ), to the second element (ST 2 ) of the second planetary gear set (RS 2 ); the second element (ST 1 ) of the first planetary gear set (RS 1 ) is connectable, via the third clutch (K 3 ), to the first element (SO 4 ) of the fourth planetary gear set (RS 4 ) which forms at least a portion of the seventh shaft ( 7 ); the first element (SO 2 ) of the second planetary gear set (RS 2 ) forms at least a portion of the fourth shaft ( 4 ) and is connectable, via the second brake (B 2 ), to the housing; the third element (H 2 ) of the second planetary gear set (RS 2 ) forms at least a portion of the third shaft ( 3 ) and is connectable, via the first brake (B 1 ), to the housing; the third element (H 2 ) of the second planetary gear set (RS 2 ) is coupled, via the third shaft ( 3 ), to the third element (H 4 ) of the fourth planetary gear set (RS 4 ); the first element (SO 4 ) of the fourth planetary gear set (RS 4 ) forms at least a portion of the seventh shaft ( 7 ) and is connectable, via the second clutch (K 2 ), to the drive shaft (AN); the second element (ST 4 ) of the fourth planetary gear set (RS 4 ) forms at least a portion of the second shaft ( 2 ) and is coupled to the output shaft (AB); and exactly three of the first clutch (K 1 ), the second clutch (K 2 ), the third clutch (K 3 ), the fourth clutch (K 4 ), the first brake (B 1 ) and the second brake (B 2 ) are engaged for each of the up to nine forward gears to be implemented.