A planetary gear train of an automatic transmission for a vehicle may include a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, an input shaft mounted with the first, second, and third planetary gear sets, an output shaft mounted with the 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, a sixth shaft selectively connectable with the fourth shaft, a seventh shaft selectively connectable with the input shaft, an eighth shaft gear-meshed with one shaft among the fourth and seventh shafts, a ninth shaft directly connected with the output shaft, a tenth shaft gear-meshed with a remaining shaft among the fourth and seventh shafts that is not gear-meshed with the eighth shaft, and transfer gears.

A planetary gear train of an automatic transmission for a vehicle may include a first planetary gear set, a second planetary gear set, a third planetary gear set, an input shaft, an output shaft disposed in parallel with the input shaft, a first shaft selectively acting as a fixed element, a second shaft directly connected with the input shaft, a third shaft, a fourth shaft selectively connectable with the second shaft, a fifth shaft selectively engaged with the output shaft, a sixth shaft selectively engaged with the output shaft, and transfer gears, each gear-meshed with one of the shafts.

A planetary gear train of an automatic transmission for a vehicle may include a first planetary gear set including, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, an input shaft, an output shaft disposed in parallel with the input shaft and mounted with the fourth planetary gear set on external circumference of the output shaft, a first shaft selectively acting as a fixed element, a second shaft directly connected with the input shaft, a third shaft, a fourth shaft selectively connectable with the second shaft, a fifth shaft, a sixth shaft engaged with the output shaft selectively, a seventh shaft selectively acting as a fixed element, an eighth shaft directly connected with the output shaft, a ninth shaft engaged with the fifth shaft, and two transfer gears, each of which is gear-meshed with one of the shafts.

An automatic transmission includes: a brake device including a friction plate set configured with fixation friction plates and rotation friction plates alternately arranged, a piston, and an oil pressure chamber supplied with oil pressure that moves the piston toward the friction plate set side; a first rotating member; and second and third rotating members arranged at both respective axial sides of the first rotating member and each having an outer diameter smaller than that of the first rotating member. The friction plate set and the oil pressure chamber are arranged at both respective axial sides of the first rotating member and also arranged at an outer periphery side of the second rotating member and at the outer periphery side of the third rotating member, respectively. The piston extends from the oil pressure chamber toward the friction plate set side through the outer periphery side of the first rotating member.

A transmission mechanism includes a plurality of drive gears disposed on a counter shaft and a plurality of driven gears disposed on a drive shaft. Each of the plurality of drive gears is engaged with each of the plurality of driven gears to forma plurality of shift-gear pairs. An eight-speed drive gear, which forms an eight-speed shift-gear pair having the smallest reduction gear ratio, and a seven-speed drive gear, which forms a seven-speed shift-gear pair having the second smallest reduction gear ratio, are disposed adjacent one another at a center portion of an arrangement of the drive gears. An eight-speed driven gear, which forms the eight-speed shift-gear pair, and a seven-speed driven gear, which forms the seven-speed shift-gear pair, are disposed adjacent one another at a center portion of an arrangement of the driven gears.

The present disclosure provides a multiple speed transmission having an input member, an output member, a plurality of planetary gearsets, a plurality of interconnecting members and a plurality of torque-transmitting mechanisms. The plurality of planetary gear sets includes first, second and third members. The input member is continuously interconnected with at least one member of one of the plurality of planetary gear sets, and the output member is continuously interconnected with another member of one of the plurality of planetary gear sets. At least eight forward speeds and one reverse speed are achieved by the selective engagement of the five torque-transmitting mechanisms.

A transmission device that includes a first clutch that includes a first clutch drum, a first piston, and a first engagement oil chamber; and a second clutch that includes a second clutch drum fixed to an outer circumferential portion of the first clutch drum, a second piston, and a second engagement oil chamber.

A double clutch transmission (DCT) provides eight forward speeds and one reverse speed while minimizing the number of gear trains used for changing speed and the whole length thereof. In particular, the DCT has a simple structure using four or five gear trains and four synchro devices and is capable of providing eight forward speeds and one reverse speed while reducing the entire weight thereof. In a conventional DCT, when a gear train is added to increase the number of speed stages, the whole length thereof is increased. The provided DCT can minimize the whole length and the weight thereof, thereby reducing the manufacturing cost, the number of parts, and the fuel efficiency.

Proposed is a multi-stage transmission in planetary design in a housing (9) for a vehicle comprising at least one electric motor (EM) and comprising three planetary gear sets (RS1, RS2, RS3), wherein a drive (An) can be connected by means of a shift element (K0) to a first shaft (1), and an output (Ab) is connected to a second shaft (2), wherein there are provided four additional shafts (3, 4, 5, 6) and at least five shift elements (B1, K1, K2, K3, K4), through the actuation of which at least eight forward gears (G1, G2, G3, G4, G5, G6, G7, G8) can be implemented. According to the invention, the first element of the first planetary gear set (RS1) is connected to the housing (9), wherein the first shaft (1) is permanently connected to the second element of the first planetary gear set (RS1); wherein the rotor (10) of the electric motor (EM) is connected to the third element of the first planetary gear set (RS1); and wherein the third element of the first planetary gear set (RS1) can be connected by means of at least one shift element (K3, K4) to at least one element of at least one additional planetary gear set (RS2, RS3).

A planetary gear train of an automatic transmission for a vehicle includes 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 rotational elements, a first shaft, a second shaft, a third shaft, a fourth shaft, a fifth shaft connecting the sixth rotational element to the seventh rotational element and selectively connected to the input shaft or the third shaft, a sixth shaft connecting the eighth rotational element to the twelfth rotational element, a seventh shaft connected to the ninth rotational element, and an eighth shaft connected to the eleventh rotational element, selectively connected to the fourth shaft and directly connected to the output shaft.