Multi-speed gearbox

A multi-stage transmission of a planetary design comprising:

• a drive shaft (1),
• an output shaft (2),
• first, second, third and fourth planetary gear sets (P1, P2, P3, P4) which are arranged within a housing (G),
• third, fourth, fifth, six, seventh and eighth rotatable shafts (3, 4, 5, 6, 7, 8), and
• six shift elements (03, 04, 05, 14, 17, 18) comprising brakes (03, 04, 05) and clutches (14, 17, 18) whose selective engagement generates different transmission ratios between the drive shaft (1) and the output shaft (2) such that nine forward gears and one reverse gear are implementable,
• wherein the fifth shaft (5) is connected to both the sun gear of the first planetary gear set (P1) and the sun gear of the second planetary gear set (P2) and the fifth shaft (5) can be coupled to the housing (G) by a third brake (05),
• the drive shaft (1) can be releasably connected, by a first clutch (14), to the fourth shaft (4), the fourth shaft (4) is connected to the carrier of the second planetary gear set (P2) and can be coupled, by a second brake (04), to the housing (G),
• the drive shaft (1) can be releasably connected, by a second clutch (17), to the seventh shaft (7) which is connected to both the ring gear of the second planetary gear set (P2) and the sun gear of the third planetary gear set (P3), and the seventh shaft (7) can be releasably connected, by a third clutch (18), to the eighth shaft (8), which is connected to the ring gear of the fourth planetary gear set (P4) and the carrier of the third planetary gear set (P3),
• the sixth shaft (6) is connected to both the ring gear of the third planetary gear set (P3) and the carrier of the first planetary gear set (P1),
• the third shaft (3) is connected to the sun gear of the fourth planetary gear set (P4) and can be coupled, by a first brake (03), to the housing (G), and
• the output shaft (2) is connected to both the carrier of the fourth planetary gear et (P4) and the ring gear of the first planetary gear set (P1).

A multi-stage transmission of a planetary design comprising:

• a drive shaft,
• an output shaft,
• first, second, third and fourth planetary gear sets which are arranged within a housing,
• third, fourth, fifth, six, seventh and eighth rotatable shafts, and
• six shift elements comprising brakes and clutches whose selective engagement generates different transmission ratios between the drive shaft and the output shaft such that nine forward gears and one reverse gear are implementable,
• wherein the fifth shaft is connected to both the sun gear of the first planetary gear set and the sun gear of the second planetary gear set and the fifth shaft can be coupled to the housing by a third brake,
• the drive shaft can be releasably connected, by a first clutch, to the fourth shaft, the fourth shaft is connected to the carrier of the second planetary gear set (P2) and can be coupled, by a second brake, to the housing,
• the drive shaft can be releasably connected, by a second clutch, to the seventh shaft which is connected to both the ring gear of the second planetary gear set and the sun gear of the third planetary gear set, and the seventh shaft can be releasably connected, by a third clutch, to the eighth shaft, which is connected to the ring gear of the fourth planetary gear set and the carrier of the third planetary gear set,
• the sixth shaft is connected to both the ring gear of the third planetary gear set and the carrier of the first planetary gear set,
• the third shaft is connected to the sun, gear of the fourth planetary gear set and can be coupled, by a first brake, to the housing, and
• the output shaft is only directly connected to both the carrier of the fourth planetary gear set and the ring gear of the first planetary gear set.