Ten or more forward speeds and at least four reverse speeds 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 from an engine, an output shaft, and first, second, third, and fourth planetary gear sets each including three rotation elements. The gear train also includes eight shafts for selectively connecting the planetary gear sets and the input and output shafts in various configurations to achieve at least ten forward speeds and at least four reverse speeds.

A group transmission device includes an upshift assembly with a first transmission element, a second transmission element and a third transmission element. A downshift assembly has a first transmission element, a second transmission element and a third transmission element. A main shaft is arranged coaxially to the upshift assembly and a layshaft is arranged parallel to the main shaft. A first idler gear is arranged coaxially to the main shaft and axially between the upshift assembly and the downshift assembly and is connectable to the main shaft for conjoint rotation by a first shift unit. The first idler gear is connectable to the third transmission element of the downshift assembly for conjoint rotation by a second shift unit.

A multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers to achieve at least nine forward speed ratios and at least nine reverse speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset, a second planetary gearset, a third planetary gearset, a fourth planetary gearset, and a fifth planetary gearset. The plurality of selective couplers may include a number of clutches and a number of brakes. The multi-speed transmission may have five planetary gearsets and eight selective couplers. The eighth selective couplers may include three clutches and five brakes.

A system for operating a work vehicle may include an engine and a transmission coupled to the engine. The transmission may include a planetary gear unit configured to be selectively coupled to the engine by engaging one of two directional clutches of the transmission. The transmission may also include a hydrostatic drive unit having an input configured to be rotationally coupled to the engine and an output configured to be rotationally coupled to the planetary gear unit. Moreover, the transmission may include a bypass shaft assembly having a bypass shaft configured to be selectively coupled between the output of the hydrostatic drive unit and a given range clutch of the transmission via a bypass clutch. In addition, the system may include a controller configured to operate the transmission in a hydrostatic bypass mode by disengaging the directional clutches and by engaging the bypass clutch and the given range clutch.

A first carrier rotates integrally with an input shaft. A third sun gear and a fourth sun gear rotate integrally with a first intermediate shaft. A third carrier rotates integrally with a second ring gear. A fourth carrier rotates integrally with a third ring gear, and outputs power. A first clutch couples a first ring gear and a second sun gear to the first intermediate shaft. A second clutch couples the first carrier to a second carrier. A third clutch couples the second carrier to the first intermediate shaft. A first brake brakes rotation of a first sun gear. A second brake brakes rotation of the second ring gear and the third carrier. A third brake brakes rotation of a fourth ring gear.

A drive system for a hybrid or electric vehicle that includes a transmission with four forward and four reverse gears. The transmission optionally includes a first and a second planetary gearset, and optionally a first and second range selector assembly. The range selector assemblies may include a clutch and a brake, and/or a synchronizer. The drive system may include a single electric motor with any example of a transmission of the present disclosure, or multiple electric motors individually driving separate transmissions. The motors may be arranged upstream or downstream of portions of a transmission, and they may be aligned parallel with or perpendicular to a drive axle, input shaft, output shaft, and any suitable combination thereof. An internal combustion engine may be included as well.

An eight and sixteen forward gear planetary gear mechanism automatic transmission series, where it includes eight forward speeds realized by combining three simple planetary gear sets, five clutches, plus improved and adapted sixteen forward speeds realized by combining four simple planetary gear sets, six clutches. In this solution, a major type of synchronizer clutch being used corresponding to each planetary gear set. The gear train also uses ratchet and pawl pair clutch structure as an alternative option, so that the automatic transmission has a more compact overall structure, the gearshift efficiency is high, the synchronous responsiveness and stability are excellent. The transmission series has wide and uniform transmission gear ratios, making-capacity maximum to achieve 26:1; and the shift unit is simple and reliable, which can significantly enhance the maneuverability of the vehicle driving and reduce fuel consumption and greenhouse gas emissions.

Arrangement of reversing double-flow gearbox for motor vehicles and construction machines, with two branches of output flow, consisting of an input shaft (13) equipped with a tooth wheel, engaged with a tooth wheel of a first disc clutch (1) and with a tooth wheel of a second disc clutch (2), wherein an output shaft (11) of the first disc clutch (1) houses a first set (3) of tooth wheels and a third set (5) of tooth wheels that are engaged through a first synchronization clutch (61) and a second synchronization clutch (62) with a set of tooth wheels arranged on the output shaft (10) of the gearbox, while an output shaft (12) of the second disc clutch (2) houses a second set (4) of tooth wheels and a fourth set (7) of tooth wheels that are engaged through a third synchronization clutch (63) and a fourth synchronization clutch (64) with a set of tooth wheels arranged on the output shaft (10) of the gearbox, wherein the output shaft (11) of the first disc clutch (1) and the output shaft (12) of the second disc clutch (2) are inter-connected by an inserted set of gears (8) with a gearing synchronization clutch (9) arranged on the output shaft (12) of the second clutch disc (2) or on output shaft (11) of the first disc clutch (1).

A method of operating dual-clutch transmission for a vehicle which has two partial transmissions, each partial transmission having an input shaft arranged on an input shaft axis. An output shaft is arranged on the input shaft axis or a parallel countershaft axis. An intermediate gear system on the countershaft axis. At least one input shaft can be connected to the drive output shaft, as a direct drive, and only one countershaft is arranged on the countershaft axis and supports only fixed gears. One of the gears is a direct gear so that, when the direct gear is engaged, all the shifting elements, for coupling the intermediate gear system via the gear planes into the force flow, can be disengaged. Each gear plane can be coupled by a shifting element arranged on the input shaft axis to a shaft, and the gear next-lower than the direct gear is a coupling gear.