Planetary gear train of automatic transmission for vehicles

A planetary gear train of an automatic transmission for vehicles, comprising:nan input shaft adapted to receive engine torque;an output gear adapted to output a shifted torque;a first compound planetary gear set having four rotation elements by combining first and second planetary gear sets and adapted to primarily shift torque input through two input paths into six speed ratio and to output the primarily shifted torque;a second compound planetary gear set having four rotation elements by combing third and fourth planetary gear sets and adapted to secondarily shift the torque input from the first compound planetary gear set and the torque input from the input shaft through one path into multiple shift-speeds and to output the multiple shift-speeds;eight rotational members including two rotation elements connected to each other or one rotation element among the rotation elements of the first and second compound planetary gear sets; andseven friction members including three clutches interposed between a selected rotational member among the rotational members and the input shaft and adapted to selectively transmit the torque and four brakes interposed between a selected rotational member among the rotational members and a transmission housing;wherein the second compound planetary gear set comprises:the third planetary gear set being a single pinion planetary gear set having a third sun gear, a third planet carrier, and a third ring gear;the fourth planetary gear set being a single pinion planetary gear set having a fourth sun gear, a fourth planet carrier, and a fourth ring gear;a fifth rotational member including the fourth sun gear and adapted to be directly connected to the first planet carrier and the second ring gear of the first compound planetary gear set;a sixth rotational member including the third ring gear and the fourth planet carrier and adapted to be selectively connected to the input shaft;a seventh rotational member including the third planet carrier and the fourth ring gear and adapted to be directly connected to the output gear;an eighth rotational member including the third sun gear and adapted to be selectively connected to the transmission housing;a third clutch interposed between the input shaft and the sixth rotational member;a third brake interposed between the eighth rotational member and the transmission housing.

A planetary gear train of an automatic transmission for vehicles, comprising:nan input shaft adapted to receive engine torque;an output gear adapted to output a shifted torque;a first compound planetary gear set having four rotation elements by combining first and second planetary gear sets and adapted to primarily shift torque input through two input paths into six speed ratio and to output the primarily shifted torque;a second compound planetary gear set having four rotation elements by combing third and fourth planetary gear sets and adapted to secondarily shift the torque input from the first compound planetary gear set and the torque input from the input shaft through one path into multiple shift-speeds and to output the multiple shift-speeds;eight rotational members including two rotation elements connected to each other or one rotation element among the rotation elements of the first and second compound planetary gear sets; andseven friction members including three clutches interposed between a selected rotational member among the rotational members and the input shaft and adapted to selectively transmit the torque and four brakes interposed between a selected rotational member among the rotational members and a transmission housing;wherein the second compound planetary gear set comprises:nthe third planetary gear set being a single pinion planetary gear set having a third sun gear, a third planet carrier, and a third ring gear;the fourth planetary gear set being a single pinion planetary gear set having a fourth sun gear, a fourth planet carrier, and a fourth ring gear;a fifth rotational member including the third ring gear and adapted to be directly connected to a common ring gear of the first compound planetary gear set;a sixth rotational member including the third planet carrier and the fourth ring gear and adapted to be selectively connected to the input shaft;a seventh rotational member including the fourth planet carrier and adapted to be directly connected to the output gear;an eighth rotational member including the third sun gear and the fourth sun gear and adapted to be selectively connected to the transmission housing;a third clutch interposed between the input shaft and the sixth rotational member; and a third brake interposed between the eighth rotational member and thetransmission housing.

A planetary gear train of an automatic transmission for vehicles realizing multiple shift-speeds, comprising:nan input shaft adapted to receive engine torque;an output gear adapted to output a shifted torque;a first compound planetary gear set formed by combining a first planetary gear set having a first sun gear, a first planet carrier, and a first ring gear as rotation elements thereof and a second 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 formed by combining a third planetary gear set having a third sun gear, a third planet carrier, and a third ring gear as rotation elements thereof and a fourth planetary gear set having a fourth sun gear, a fourth planet carrier, and a fourth ring gear as rotation elements thereof;a first rotational member including the first sun gear and adapted to be selectively connected to a transmission housing;a second rotational member including the first planet carrier and the second ring gear;a third rotational member including the first ring gear and the second planet carrier and adapted to be selectively connected to the input shaft or to the transmission housing;a fourth rotational member including the second sun gear and adapted to be selectively connected to the input shaft or to the transmission housing;a fifth rotational member including the fourth sun gear and adapted to be directly connected to the first planet carrier and the second ring gear of the first compound planetary gear set;a sixth rotational member including the third ring gear and the fourth planet carrier and adapted to be selectively connected to the input shaft;a seventh rotational member including the third planet carrier and the fourth ring gear and adapted to be directly connected to an output gear;an eighth rotational member including the third sun gear and adapted to be selectively connected to the transmission housing; andseven friction members including clutches interposed between selected rotational members among the eight rotational members or between a selected rotational member and the input shaft and brakes interposed between a selected rotational member among the rotational members and the transmission housing.

A planetary gear train of an automatic transmission for vehicles realizing multiple shift-speeds, comprising:nan input shaft adapted to receive engine torque;an output gear adapted to output a shifted torque;a first compound planetary gear set being a compound planetary gear set of Ravingneaux type having a first sun gear engaged with a short pinion, a second sun gear engaged with a long pinion, a common planet carrier, and a common ring gear;a second compound planetary gear set formed by combining a third planetary gear set having a third sun gear, a third planet carrier, and a third ring gear as rotation elements thereof and a fourth planetary gear set having a fourth sun gear, a fourth planet carrier, and a fourth ring gear as rotation elements thereof;a first rotational member including the first sun gear and adapted to be selectively connected to a transmission housing;a second rotational member including the common ring gear;a third rotational member including the common planet carrier and adapted to be selectively connected to the input shaft or to the transmission housing;a fourth rotational member including the second sun gear and adapted to be selectively connected to the input shaft or to the transmission housing;a fifth rotational member including the third ring gear and adapted to be directly connected to the common ring gear of the first compound planetary gear set;a sixth rotational member including the third planet carrier and the fourth ring gear and adapted to be selectively connected to the input shaft;a seventh rotational member including the fourth planet carrier and adapted to be directly connected to an output gear;an eighth rotational member including the third sun gear and the fourth sun gear and adapted to be selectively connected to the transmission housing; andseven friction members including clutches interposed between selected rotational members among the eight rotational members or between a selected rotational member and the input shaft and brakes interposed between a selected rotational member among the rotational members and the transmission housing.