Patent ID: 8506443

Claim:
A planetary gear train of an automatic transmission for vehicles, comprising: an input shaft configured to receive an engine torque; an output shaft configured to output a shifted torque; a first compound planetary gear set including a first simple planetary gear set having a first sun gear, a first planet carrier, and a first ring gear as rotation elements thereof and a second simple planetary gear set having a second sun gear, a second planet carrier, and a second ring gear as rotation elements thereof; a second compound planetary gear set including a third simple planetary gear set having a third sun gear, a third planet carrier, and a third ring gear as rotation elements thereof and a fourth simple planetary gear set having a fourth sun gear, a fourth planet carrier and a fourth ring gear as rotation elements thereof; seven rotational shafts each connecting to one or more rotation elements among the rotation elements of the first and second compound planetary gear sets; and seven friction members including three clutches each interposed between a rotational shaft selected among the rotational shafts and the input shaft so as to control torques and four brakes each selectively connecting a rotational shaft selected among the rotational shafts to a transmission housing; wherein the first compound planetary gear set includes four rotational shafts among the seven rotational shafts and is adapted to receive a torque of the input shaft through two paths and to output four speed ratios; and wherein the second compound planetary gear set is connected to one of the four rotational shafts in the first compound planetary gear set and includes three other rotational shafts which are not included in the first compound planetary gear set, and the second compound planetary gear set is adapted to receive a torque from the first compound planetary gear set and the torque of the input shaft through one of the two paths and to output ten forward speeds and four reverse speeds.