Patent ID: 7645208

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 eighth forward gears and at least one reverse gear can be implemented; wherein the carrier (ST 4 ) of the fourth planetary gearset (RS 4 ) and the input drive shaft (AN) are permanently connected and form the first shaft ( 1 ); the ring gear (HO 2 ) of the second planetary gearset (RS 2 ) and the carrier (ST 3 ) of the third planetary gearset (RS 3 ) and the output drive shaft (AB) are connected to one another and form the second shaft ( 2 ); the sun gear (SO 1 ) of the first planetary gearset (RS 1 ) and the sun gear (SO 4 ) of the fourth planetary gearset (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 3 ) of the third planetary gearset (RS 3 ) forms the fifth shaft ( 5 ); the ring gear (HO 1 ) of the first planetary gearset (RS 1 ) and the ring gear (HO 3 ) of the third planetary gear (RS 3 ) are permanently connected and form the sixth shaft ( 6 ); the sun gear (SO 2 ) of the second planetary gearset (RS 2 ) and the ring gear (HO 4 ) of the fourth planetary gearset (RS 4 ) are permanently connected and form the seventh shaft ( 7 ); the carrier (ST 2 ) of the second planetary gearset (RS 2 ) forms the eighth shaft ( 8 ); the first shifting element (A) is arranged between the third shaft ( 3 ) and a transmission housing (GG) of the transmission; the second shifting element (B) is arranged between the fourth shaft ( 4 ) and the transmission housing (GG) of the transmission; the third shifting element (C) is arranged, in a direction of power flow, between the first shaft ( 1 ) and the fifth shaft ( 5 ); 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 seventh shaft ( 7 ).