Multi-speed gearbox

A multi-stage transmission of a planetary design comprising:

• a driveshaft (1),
• an output shaft (2),
• first, second, third and fourth planetary gear sets (P1, P2, P3, P4) which are disposed within a housing (G) and each of the first, the second, the third and the fourth planetary gear sets comprises a ring gear, a carrier, planet gears and a sun gear,
• third, fourth, fifth, six, seventh and eighth rotatable shafts (3, 4, 5, 6, 7, 8),
• six shift elements (04, 05, 15, 17, 18, 37) comprising brakes (04, 05) and clutches (15, 17, 18, 37), and selective engagement of the six shift elements (04, 05, 15, 17, 18, 37) generates different transmission ratios between the driveshaft (1) and the output shaft (2) such that nine forward gears and one reverse gear are implementable,
• wherein the sun gear of the first planetary gear set (P1) is connected to the fifth shaft (5), the fifth shaft (5) can be coupled to the housing (G) by engagement of a second brake (05) and the fifth shaft (5) can be detachably connected, by engagement of a first clutch (15), to the drive shaft (1),
• the drive shaft (1) can be detachably connected, by engagement of a second clutch (17), to the seventh shaft (7) connected to the carrier of the second planetary gear set (P2),
• the drive shaft (1) can be detachably connected, by engagement of a third clutch (18), to the eighth shaft (8) which is connected to both the carrier of the first planetary gear set (P1) and to the sun gear of the second planetary gear set (P2),
• the seventh shaft (7) can be detachably connected, by engagement of a fourth clutch (37), to the third shaft (3) which is connected to the ring gear of the third planetary gear set (P3),
• the sixth shaft (6) is connected to both the ring gear of the second planetary gear set (P2) and the carrier of the fourth planetary gear set (P4),
• the fourth shaft (4) is connected to both the ring gear of the first planetary gear set (P1) and to the sun gear of the fourth planetary gear set (P4), and the fourth shaft (4) can be coupled to the housing (G) by engagement of a first brake (04),
• the sun gear of the third planetary gear set (P3) is coupled to the housing (G), and
• the output shaft (2) is directly connected to both the carrier of the third planetary gear set (P3) and to the ring gear of the fourth planetary gear set (P4).