The automatic transmission which includes a third brake element formed by a support member including a first cylindrical portion having a first sliding surface at an outer peripheral surface thereof, a second cylindrical portion having a second sliding surface at an inner peripheral surface thereof and a third cylindrical portion having a third sliding surface at an inner peripheral surface thereof, an inner side piston, inner edge portion of which is in contact with the first sliding surface and an outer edge portion of which is in contact with the second sliding surface and an outer side piston which includes a first piston cylindrical portion, outer edge of which is in contact with the second sliding surface over an entire periphery thereof and a second piston cylindrical portion, outer edge portion of which is in contact with the third sliding surface over an entire periphery thereof.

An automotive multistage transmission may include an input shaft and an output shaft, a first planetary gear set, a second planetary gear set, a third planetary gear set, and a fourth planetary gear set each including three rotary members and transmitting torque between the input shaft and the output shaft, and at least six shifting members connected to the rotary members of the planetary gear sets.

A planetary gear train of an automatic transmission for a vehicle may include an input shaft receiving torque of an engine, an output shaft outputting torque of the engine, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first shaft, a second shaft, a third shaft selectively connectable to the input shaft, and selectively connectable to a transmission housing, a fourth shaft selectively connectable to the input shaft, a fifth shaft directly connected to the output shaft, a sixth shaft, and a seventh shaft selectively connectable to the input shaft.

A planetary gear train of an automatic transmission for a vehicle includes: an input shaft receiving torque of an engine; an output shaft outputting the torque; a first planetary gear set including a first, a second, and a third rotation element; a second planetary gear set including a fourth, a fifth, and a sixth rotation element; a third planetary gear set including a seventh, an eighth, and a ninth rotation element; and a fourth planetary gear set including a tenth, an eleventh, and a twelfth rotation element. The gear train includes a first shaft connected to the first rotation element; a second shaft connecting the second rotation element to the fourth rotation element and the seventh rotation element and connected to the input shaft; a third shaft connecting the third rotation element to the eleventh rotation element; a fourth shaft connecting the fifth rotation element to the twelfth rotation element and connected to the output shaft; a fifth shaft connected to the sixth rotation element and selectively connected to the third shaft; a sixth shaft connected to the eighth rotation element; a seventh shaft connected to the ninth rotation element; and an eighth shaft connected to the tenth rotation element, selectively connected to the sixth shaft, and selectively connected to the seventh shaft.

A power shiftable multi-stage transmission of a planetary design and disposed between an input drive shaft and an output shaft for a vehicle. The multi-stage transmission has two parallel shaft trains, six shift elements, at least two spur gear stages and three planetary gear sets. Each of the planetary gear sets has a sun gear, a ring gear and a planet carrier combined in a carrier having multiple planetary gears. The two shaft trains may be connected to one another via the at least two spur gear stages. Different transmission ratios, between the input drive shaft and the output shaft, may be achieved by selective engagement of the six shift elements such that a plurality of forward gears, at least nine forward gears, and at least one reverse gear, may be implemented.

A planetary gear train of an automatic transmission for a vehicle may include an input shaft receiving torque of an engine, an output shaft outputting torque of the engine, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first shaft, a second shaft, a third shaft selectively connectable to at least one of the input shaft and a transmission housing, a fourth shaft selectively connectable to the input shaft, a fifth shaft selectively connectable to the input shaft, a sixth shaft directly connected to the output shaft, and a seventh shaft.

A planetary gear train of a transmission for a vehicle is provided. Nine or more forward speeds and one or more reverse speeds are achieved by a planetary gear train of an automatic transmission for a vehicle including an input shaft and an output shaft. A first planetary gear set has first, second, and third rotation elements. A second planetary gear set has fourth, fifth, and sixth rotation elements. A third planetary gear set has seventh, eighth, and ninth rotation elements. A fourth planetary gear set has tenth, eleventh, and twelfth rotation elements and eight shaft element . . .

A planetary gear train of claim of an automatic transmission for a vehicle may include an input shaft for receiving an engine torque, an output shaft for outputting a shifted torque, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first shaft, a second shaft directly connected with the input shaft, a third shaft, a fourth shaft, a fifth shaft selectively connectable with the fourth shaft, a sixth shaft selectively connectable with the fourth shaft, a seventh shaft selectively connectable with the sixth shaft, and an eighth shaft directly connected with the output shaft, and selectively connectable with the fifth shaft.

At least nine forward speeds and at least one reverse speed are achieved by a planetary gear train of an automatic transmission for a vehicle including an input shaft, an output shaft, four planetary gear sets respectively having three rotational elements, and six control elements for selectively interconnecting the rotational elements and a transmission housing.

A planetary gear train of an automatic transmission for a vehicle may include an input shaft receiving torque of an engine, an output shaft outputting torque, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first shaft, a second shaft, a third shaft, a fourth shaft, a fifth shaft selectively connectable to at least one of the second shaft and the third shaft, and directly connected to the input shaft, a sixth shaft connected to the ninth rotation element, a seventh shaft connected to the tenth rotation element, and an eighth shaft connected to the eleventh rotation element, selectively connectable to the sixth shaft, and directly connected to the output shaft.