Multi-stage gearbox

A multi-stage transmission of a planetary design for an automatic transmission of a motor vehicle, the multi step transmission comprising:

• a drive shaft (1) and an output shaft (2) which are disposed in a transmission housing (G);
• first, second, third and fourth planetary gear sets (P1, P2, P3, P4), each of the first, the second, the third, and the fourth planetary gear sets (P1, P2, P3, P4) comprising a sun gear, a carrier and a ring gear;
• a third rotatable shaft (3), a fourth rotatable shaft (4), a fifth rotatable shaft (5), a sixth rotatable shaft (6), a seventh rotatable shaft (7) and at least one eighth rotatable shaft (8);
• at least six shift elements (03, 05, 07, 13, 16, 18) comprising a first brake (03), a second brake (05), a third brake (07), a first clutch (13), a second clutch (16), and a third clutch (18) whose selected engagement produces different transmission ratios between the drive shaft (1) and the output shaft (2) such that nine forward gears and a reverse gear can be achieved;
• the first and the second planetary gear sets (P1, P2) form a shiftable front-mounted gear set, and the third and the fourth planetary gear sets (P3, P4) form a main gear set;
• wherein the ring gear of the second planetary gear set (P2) is connectable to the housing (G) of the transmission by the fifth shaft (5) via the second brake (05);
• the seventh shaft (7) is connected to at least one element of the main gear set, and is connectable to the housing (G) of the transmission via the third brake (07);
• the sixth shaft (6) is connected to at least one further element of the main gear set, and is connectable to the drive shaft (1) via the second clutch (16);
• the output shaft (2) is connected to at least one other element of the main gear set;
• the front-mounted gear set is shiftable;
• the carriers of the first and the second planetary gear sets (P1, P2) are coupled together via the fourth shaft (4) which is connected to an additional element of the main gear set;
• the ring gear of the first planetary gear set (P1) is coupled to the sun gear of the second planetary gear set (P2) via the eighth shaft (8) which is connectable to the drive shaft (1) via the third clutch (18);
• and
• the sun gear of the first planetary gear set (P1) is connectable to the housing (G) of the transmission by the third shaft (3), via the first brake (03), and the third shaft (3) is connectable to the drive shaft (1) via the first clutch (13).