Patent ID: 7211021

Claim:
A multi-step reduction gear transmission of a planetary construction for a motor vehicle, the multi-step reduction gear including: a drive shaft ( 1 ) and an output shaft ( 2 ) which are arranged in a housing (G), first, second and third planetary gear sets (P 1 , P 2 , P 3 ), at least third, fourth, fifth, sixth and seventh rotating shafts ( 3 , 4 , 5 , 6 , 7 ), as well as at least six shifting elements ( 03 , 04 , 14 , 16 , 37 , 57 ), including first and second brakes ( 03 , 04 ) and first second, third, and fourth clutches ( 14 , 16 , 37 , 57 ), whose selective engagement brings about different reduction ratios between the drive shaft ( 1 ) and the output shaft ( 2 ) so that seven forward gears and one reverse gear can be realized, wherein drive takes place through the drive shaft ( 1 ) which is continuously connected with a sun wheel of the first planetary gears (P 1 ), output takes place through the output shaft ( 2 ) which is continuously connected with an annulus of the second planetary gear set (P 2 ) and a first element of the third planetary gear set (P 3 ), the third shaft ( 3 ) is continuously connected with a planet carrier of the first planetary gears (P 1 ), the fourth shaft ( 4 ) is continuously connected with a planet carrier of the second planetary gears (P 2 ) and also with a further element of the third planetary gear set (P 3 ), the fifth shaft ( 5 ) is continuously connected with an annulus of the first planetary gear set (P 1 ), the sixth shaft ( 6 ) is continuously connected with a sun wheel of the third planetary gear set (P 3 ), the seventh shaft ( 7 ) is continuously connected with a sun wheel of the second planetary gear set (P 2 ), and the third shaft ( 3 ) can be coupled to the housing (G) via the first brake ( 03 ), the fourth shaft ( 4 ) can be coupled to the housing (G) via the second brake ( 04 ), the first clutch ( 14 ) detachably connects the drive shaft ( 1 ) and the fourth shaft ( 4 ) with one another, the second clutch ( 16 ) detachably connects the drive shaft ( 1 ) and the sixth shaft ( 6 ) with one another, the third clutch ( 37 ) detachably connects the third shaft ( 3 ) and the seventh shaft ( 7 ) with one another, and the fourth clutch ( 57 ) detachably connects the fifth shaft ( 5 ) and the seventh shaft ( 7 ) with one another.