Patent ID: 7651430

Claim:
A multi-speed automatic transmission of a planetary design for a motor vehicle, the transmission comprising: an input shaft (AN), an output shaft (AB); first, second, third and fourth planetary gearsets (RS 1 , RS 2 , RS 3 , RS 4 ), and each of the first, the second, the third and the fourth planetary gearsets (RS 1 , RS 2 , RS 3 , RS 4 ) comprising a sun gear, a carrier and a ring gear; at least first, second, third, fourth, fifth, sixth, seventh and eighth rotatable shafts ( 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ) and first, second, third, fourth and fifth shifting elements (A, B, C, D, E), whose selective engagement creates different gear ratios between the input shaft (AN) and the output shaft (AB) so that eight forward gears and at least one reverse gear can be implemented; wherein the ring gear (HO 2 ) of the second planetary gear set (RS 2 ) and the input shaft (AN) are permanently connected and form the first shaft ( 1 ); the carrier (ST 3 ) of the third planetary gear set (RS 3 ) and the output shaft (AB) are permanently connected and form the second shaft ( 2 ); the sun gear (SO 1 ) of the first planetary gear set (RS 1 ) and the sun gear (SO 4 ) of the fourth planetary gear set (RS 4 ) are permanently connected and form the third shaft ( 3 ); the carrier (ST 1 ) of the first planetary gearset (RS 1 ) forms the fourth shaft ( 4 ); the sun gear (SO 2 ) of the second planetary gear set (RS 2 ) and the sun gear (SO 3 ) of the third planetary gear set (RS 3 ) are permanently connected and form the fifth shaft ( 5 ); the ring gear (HO 1 ) of the first planetary gear set (RS 1 ) and the ring gear (HO 3 ) of the third planetary gear set (RS 3 ) are permanently connected and form the sixth shaft ( 6 ); the carrier (ST 2 ) of the second planetary gear set (RS 2 ) and the carrier (ST 4 ) of the fourth planetary gear set (RS 4 ) are permanently connected and form the seventh shaft ( 7 ); the ring gear (HO 4 ) of the fourth planetary gear set (RS 4 ) forms the eighth shaft ( 8 ); the first shifting element (A) is arranged between the third shaft ( 3 ) and a transmission housing (GG); the second shifting element (B) is arranged between the fourth shaft ( 4 ) and transmission housing (GG); the third shifting element (C) is arranged, in a direction of power flow, between one of the first shaft ( 1 ) and the fifth shaft ( 5 ), the first shaft ( 1 ) and the seventh shaft ( 7 ), and the fifth shaft ( 5 ) and the seventh shaft ( 7 ); the fourth shifting element (D) is arranged, in the direction of the power flow, between the sixth shaft ( 6 ) and the eighth shaft ( 8 ); and the fifth shifting element (E) is arranged, within the power flow, between the fifth shaft ( 5 ) and the eighth shaft ( 8 ).