Patent ID: 8430785

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 ) each 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 and third clutches (K 1 , K 2 , K 3 ) and first, second and third brakes (B 1 , B 2 , B 3 ), whose selective engagement achieve different transmission ratios between the drive shaft (AN) and the output shaft (AB) so that at least first, second, third, fourth, fifth, sixth, seventh, eighth and ninth forward gears can be implemented; the drive shaft (AN) being coupled to the third element (H 1 ) of the first planetary gear set (RS 1 ) and forming the first shaft ( 1 ); the first element (SO 1 ) of the first planetary gear set (RS 1 ) forming the fifth shaft ( 5 ) and being connectable, via the third brake (B 3 ), to the housing ( 9 ); the second element (ST 1 ) of the first planetary gear set (RS 1 ) being coupled to the second element (ST 2 ) of the second planetary gear set (RS 2 ) and forming the sixth shaft ( 6 ); the first element (SO 2 ) of the second planetary gear set (RS 2 ) forming the fourth shaft ( 4 ) and being connectable, via the second brake (B 2 ), to the housing ( 9 ); the third element (H 2 ) of the second planetary gear set (RS 2 ) forming the third shaft ( 3 ) and being connectable, via the first brake (B 1 ), to the housing ( 9 ); the third element (H 2 ) of the second planetary gear set (RS 2 ) being 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 ) forming the seventh shaft ( 7 ) and being connectable, via the first clutch (K 1 ), to the drive shaft (AN); the second element (ST 4 ) of the fourth planetary gear set (RS 4 ) forming the second shaft ( 2 ) and being coupled to the output shaft (AB); and for each of the first, the second, the third, the fourth, the fifth, the sixth, the seventh, the eighth and the ninth forward gears, exactly three of the six shift elements being engaged for transmit torque from the drive shaft (AN) to the output shaft (AB).