Patent ID: 7651429

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 carrier (ST 2 ) of the second planetary gear set (RS 2 ) is permanently connected to the input shaft (AN) and forms the first shaft ( 1 ); the carrier (ST 3 ) of the third planetary gear set (RS 3 ) is permanently connected to the output shaft (AB) and forms the second shaft ( 2 ); the sun gear (SO 1 ) of the first planetary gear set (RS 1 ) is permanently connected to the sun gear (SO 4 ) of the fourth planetary gear set (RS 4 ) and forms the third shaft ( 3 ); the ring gear (HO 1 ) of the first planetary gear set (RS 1 ) forms the fourth shaft ( 4 ); the sun gear (SO 2 ) of the second planetary gear set (RS 2 ) is permanently connected to the sun gear (SO 3 ) of the third planetary gear set (RS 3 ) and forms the fifth shaft ( 5 ); the carrier (ST 1 ) of the first planetary gear set (RS 1 ) is permanently connected to the ring gear (HO 3 ) of the third planetary gear set (RS 3 ) and forms the sixth shaft ( 6 ); the ring gear (HO 2 ) of the second planetary gear set (RS 2 ) is permanently connected to the carrier (ST 4 ) of the fourth planetary gear set (RS 4 ) and forms 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 the transmission housing (GG); the third shifting element (C) is arranged, in a direction of power flow, between one of the fifth shaft( 5 ) and the seventh shaft ( 7 ), the first shaft ( 1 ) and the fifth shaft ( 5 ), and the first shaft ( 1 ) and the seventh shaft ( 7 ); the fourth shifting element (D) is arranged, in the direction of power flow, between the sixth shaft ( 6 ) and the eighth shaft ( 8 ); and the fifth shifting element (E) is arranged, in the direction of power flow, between the fifth shaft ( 5 ) and the eighth shaft ( 8 ).