A planetary gear train may include: an input shaft; an output shaft; a first planetary gear set including first, second, and third rotation elements; a second planetary gear set including fourth, fifth, and sixth rotation elements; a third planetary gear set including seventh, eighth, and ninth rotation elements; a fourth planetary gear set including tenth, eleventh, and twelfth rotation elements; four clutches, each selectively connecting at least one of the first to twelfth rotation elements to another rotation element or the input shaft; and two brakes, each selectively connectable at least one of the first to twelfth rotation elements to a transmission housing.

A planetary gear train apparatus of automatic transmission may include input and output shafts first to fifth planetary gear sets respectively having first to third, fourth to sixth, seventh to ninth, tenth to twelfth, and thirteenth to fifteenth elements, first shaft fixed to the third element and the input shaft, second shaft fixed to the fourteenth element and the output shaft, third shaft fixed to the first and fourth elements, fourth shaft fixed to the second, eighth, and fifteenth elements, fifth shaft fixed to the fifth element, sixth shaft fixed to the sixth, ninth element, and eleventh elements, and shafts, each of which is selectively connectable to housing and fixed to element of the third, fourth, and fifth planetary gear sets which is not fixed to the first to sixth shafts.

A transmission (G) for a motor vehicle. The transmission (G) has a drive shaft (GW1), an output shaft (GW2-A), first, second, third and fourth planetary gearsets (P1, P2, P3, P4) and first, second, third, fourth, fifth and sixth shift elements (B1, K1, K2, B2, K3, K4). Selective actuation of the six shift elements (B1, K1, K2, B2, K3, K4) implements eleven forward gears and two reverse gears between the drive shaft (GW1) and the output shaft (GW2-A). A drive train for a motor vehicle having such a transmission (G) is also disclosed.

A transmission (G) for a motor vehicle. The transmission (G) has a drive shaft (GW1), an output shaft (GW2-A), first, second, third and fourth planetary gearsets (P1, P2, P3, P4) and first, second, third, fourth, fifth and sixth shift elements (B1, K1, K2, B2, K3, K4). Selective actuation of the six shift elements (B1, K1, K2, B2, K3, K4) implements eleven forward gears and two reverse gears between the drive shaft (GW1) and the output shaft (GW2-A). A drive train for a motor vehicle having such a transmission (G) is also disclosed.

A transmission (G) for a motor vehicle. The transmission (G) comprises a transmission input (GW1-A), a transmission output (GW2-A), first, second, third and fourth planetary gearsets (P1, P2, P3, P4) and first, second, third, fourth, fifth and sixth shift elements (B1, B2, K1, K2, K3, K4). Ten forward gears and one reverse gear can be achieved between the transmission input (GW1-A) and the transmission output (GW2-A) by selectively operating the six shift elements (B1, B2, K1, K2, K3, K4). A drive train for a motor vehicle having such a transmission (G) is also disclosed.

A transmission (G) for a motor vehicle. The transmission (G) comprises a transmission input (GW1-A), a transmission output (GW2-A), first, second, third and fourth planetary gearsets (P1, P2, P3, P4) and first, second, third, fourth, fifth and sixth shift elements (B1, B2, K1, K2, K3, K4). Ten forward gears and one reverse gear can be achieved between the transmission input (GW1-A) and the transmission output (GW2-A) by selectively operating the six shift elements (B1, B2, K1, K2, K3, K4). A drive train for a motor vehicle having such a transmission (G) is also disclosed.

In a transmission structure according to this invention, speed change ratios of input side first and second transmission mechanisms are set so that the rotational speed of a planetary second element is the same when an HST output is set to a second HST speed in either a first transmission state or a second transmission state, and the rotational speed of a planetary first element is the same when the HST output is set to the second HST speed in either the second transmission state or the first transmission state. The speed change ratios of an output side first and second transmission mechanisms are set so that the rotational speed developed in a speed change output shaft when the HST output is set to the second HST speed is the same in either the first or second transmission states.

In a transmission structure according to this invention, speed change ratios of input side first and second transmission mechanisms are set so that the rotational speed of a planetary second element is the same when an HST output is set to a second HST speed in either a first transmission state or a second transmission state, and the rotational speed of a planetary first element is the same when the HST output is set to the second HST speed in either the second transmission state or the first transmission state. The speed change ratios of an output side first and second transmission mechanisms are set so that the rotational speed developed in a speed change output shaft when the HST output is set to the second HST speed is the same in either the first or second transmission states.

An automatic transmission includes: first, second, and third planetary gear sets each having three rotating elements; seven coupling elements variably providing a frictional force; and seven shafts. In particular, a first shaft is fixedly connected to a second rotating element of the third planetary gear set and an input shaft, a third shaft is fixedly connected to a third rotating element of the second planetary gear set, a fourth shaft is fixedly connected to a first rotating element of the second planetary gear set and a third rotating element of the third planetary gear set, a sixth shaft is directly connected to a first rotating element of the third planetary gear set and a transmission casing, a seventh shaft is fixedly connected to a third rotating element of the first planetary gear set and an output shaft, and remaining two shafts are selectively fixed to the transmission casing.

An automatic transmission includes: first, second, and third planetary gear sets each having three rotating elements; seven coupling elements variably providing a frictional force; and seven shafts. In particular, a first shaft is fixedly connected to a second rotating element of the third planetary gear set and an input shaft, a third shaft is fixedly connected to a third rotating element of the second planetary gear set, a fourth shaft is fixedly connected to a first rotating element of the second planetary gear set and a third rotating element of the third planetary gear set, a sixth shaft is directly connected to a first rotating element of the third planetary gear set and a transmission casing, a seventh shaft is fixedly connected to a third rotating element of the first planetary gear set and an output shaft, and remaining two shafts are selectively fixed to the transmission casing.