A positive-locking shifting device of a transmission connects one element of a first planetary gear set to one element of a second planetary gear set in a first shifting position and connects an additional element of the second planetary gear set to a torque-proof element of the transmission in a second shifting position. A single element of the shifting device is axially displacable between the first and second shifting positions. A shiftable operative connection between the torque-proof element of the transmission and the additional element of the second planetary gear set disposed, at least in sections, axially between the first and second planetary gear sets. The shiftable operative connection between the torque-proof element of the transmission and the additional element of the second planetary gear set intersecting a shiftable operative connection between the one element of the first planetary gear set and the one element of the second planetary gear set.

A transmission (G) includes an input shaft (GW1), an output shaft (GW2), an electric machine (EM), a plurality of planetary gear sets (P1-P3; 2P1-2P5), and gear-implementing shift elements (S1-S6; 2S1-2S5). Via engagement of a first of the gear-implementing shift elements (S1, 2S1), which is a force-locking shift element having a variable torque transmission capacity, the input shaft (GW1) and an element (E1, 22E1) of one of the planetary gear sets (P3; 2P4) can be brought into a fixed rotational speed relationship with respect to each other. Another element (E2, 22E2a, 22E2b) of one of the planetary gear sets (P1, 2P3, 2P5) is permanently connected to a rotor (R) of the electric machine (EM). By engaging an auxiliary shift element (ZS, 2ZSa, 2ZSb), which is a form-locking shift element, the rotor (R) and the input shaft (GW1) can be brought into a fixed rotational speed relationship with respect to each other.

A planetary gear train of an automatic transmission includes an input shaft; an output shaft; a first planetary gear set having first to third rotating elements; a second planetary gear set having fourth to sixth rotating elements; a third planetary gear set having seventh to ninth rotating elements; a fourth planetary gear set having tenth to twelfth rotating elements; and seven control elements, wherein the input shaft is continuously connected with the second rotating element, the output shaft is continuously connected with the eleventh rotating element, the second rotating element is continuously connected with the fourth rotating element, the third rotating element is continuously connected with the tenth rotating element, the sixth rotating element is continuously connected with the seventh rotating element, the ninth rotating element is continuously connected with the twelfth rotating element, the third rotating element and the eighth rotating element are selectively connected.

A multistage transmission, in particular for a motor vehicle, is provided at least structurally for selecting at least twelve forward transmission gears with different step-up ratios. This multistage transmission has four operatively interconnected planetary gear stages, a transmission input shaft for attaching to an internal combustion engine, a transmission output shaft, for attaching to drive wheels, four clutch units, each of which includes two clutch elements, and three brake units, each of which includes one clutch element.

A family of transmission gearing arrangements each establish at least one reverse gear ratio and between nine and fifteen forward gear ratios. A shiftable gearing arrangement establishes a variety of speed ratios between the input and a first shaft. In some embodiments, a fixed speed ratio is established upstream or downstream of the shiftable gearing arrangement. In reverse and low gear ratios, a low clutch couples the first shaft to the output. In the high gear ratios, a combining planetary gear set establishes a linear speed relationship between the first shaft, a second shaft rotating at a speed proportional to the input, and the output.

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 changed torque of the engine, 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, and seven friction elements disposed to selectively connect the rotation elements and to selectively connect the rotation elements with 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 changed torque of the engine, 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, and seven friction elements disposed to selectively connect the rotation elements with each other and selectively connect the rotation elements with a transmission housing.

A planetary carrier where the second pinion gears are disposed so as to be at least partially located in the spaces between the adjacent bridge portions, an outer peripheral surface of each of the bridge portions is provided with a spline onto which a friction engagement plate constituting a friction engagement element is fitted, an inner peripheral surface of each of the bridge portions is provided with a pair of wall portions that extend in the axial direction along side edges on both sides of each of the bridge portions and protrude radially inward, and each of the bridge portions is provided with a plurality of oil holes through which an inside and an outside of each of the bridge portions communicate with each other.

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 changed torque, 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, and seven friction elements disposed between at least one rotation element among the twelve rotation elements and another rotation element or the input shaft, or between at least one rotation element among the twelve rotation elements and a transmission housing.

A an automatic transmission includes: a first planetary gear set including a first, second, and third rotation elements; a second planetary gear set including a fourth, fifth, and sixth rotation elements; a third planetary gear set including a seventh, eighth, and ninth rotation elements; a fourth planetary gear set including a tenth, eleventh and twelfth rotation elements; a first shaft interconnecting the first and fourth rotational elements, and selectively connected to the transmission housing; a second shaft interconnecting the second and seven rotational elements, and connected with an input shaft; a third shaft connected to the third rotational element, and selectively connected to the transmission housing; a fourth shaft connected to the fifth rotational element; a fifth shaft interconnecting the sixth and eleventh rotational elements, and selectively connected to the transmission housing; and a sixth shaft interconnecting the eighth and twelfth rotational element, and connected to an output shaft.