A power transmission system includes first differential mechanism connected to an engine, and second differential mechanism. The first differential mechanism includes a first rotating element connected to the engine, and second and third rotating elements. The second differential mechanism includes a fourth rotating element connected to second rotating element, fifth rotating element connected to a first electric rotary machine, and sixth rotating element that is an output element of the second differential mechanism. The power transmission system further includes at least one of a first clutch and brake, and a second clutch. The first clutch is configured to releasably couple two of the first, second and third rotating elements to each other. The brake is configured to releasably couple the third rotating element to a stationary element. The second clutch is configured to releasably couple the third rotating element to one of the fifth and sixth rotating elements.

A first bearing device (68) rotatably supports a rotor shaft (30) of a motor (MG2) on a driven gear (24) side in an axial direction of the rotor shaft (30). A second bearing device (70) rotatably supports one (32) of a driven gear shaft (28) and an output shaft (32). The one (32) of the driven gear shaft (28) and the output shaft (32) is arranged radially inward of the other (28) one of the driven gear shaft (28) and the output shaft (32). A third bearing device (72) is arranged between an outer periphery of the one (32) of the driven gear shaft (28) and the output shaft (32) and an inner periphery of the rotor shaft (30) or an inner periphery of the other one (28) of the driven gear shaft (28) and the output shaft (32). The third bearing device (72) rotatably supports the one (32) of the driven gear shaft (28) and the output shaft (32).

A transmission includes an input shaft, an output shaft, at least four planetary gearsets, a variable-ratio unit, and at least four clutches. The input shaft is configured to receive torque from a drive unit. The output shaft is configured to transmit torque to a load. The at least four planetary gearsets, the variable-ratio unit, and the at least four clutches are arranged between the input shaft and the output shaft. The at least four clutches are selectively engageable in combination with one another to select one of at least four operating modes.

A hybrid powertrain and a method for controlling the powertrain are provided to convert an EV mode, a power slit mode, and a parallel mode based on a driving state. The powertrain includes an input shaft connected to an engine and first and second motors/generators installed within a transmission housing. A planetary gear set is installed on an input shaft and includes a combination of a sun gear, a planetary carrier, and a ring gear. A first output gear is connected to the second motor/generator and a second output gear is connected to the planetary carrier of the planetary gear set. A rotation restraint mechanism restricts a rotation of the input shaft. An overdrive brake is connected to the sun gear of the planetary gear set or the first motor/generator. An output shaft is supplied with power through the first and second output gears.

A transmission device (1) with secondarily coupled power splitting in which part of an applied torque can be conducted, in a first power branch (3) at least by way of a hydrostatic system (4), and the other part of the torque can be conducted in a second power branch (5) via mechanical system (6), located between a transmission input (7) and a transmission output (8). The hydrostatic system (4) of the first power branch (3) includes at least one pump (12) and at least one motor (13) that is functionally connected to the pump by way of a hydraulic circuit, and both of the pump and motor are adjustable. The two power paths (3, 5) can be summed by a summing gear system (9). The pump (12) is made smaller than the motor (13).

A control method for a work vehicle, includes: calculating a speed ratio indicating a ratio between a rotation speed of an input shaft connected to an engine and a rotation speed of an output shaft connected to a traveling device; and outputting a capacity command for changing at least one of a capacity of a first hydraulic pump motor and a capacity of a second hydraulic pump motor based on correlation data indicating a relationship between the speed ratio and the capacities of the first and second hydraulic pump motors, wherein the correlation data is set so that both the capacity of the first hydraulic pump motor and the capacity of the second hydraulic pump motor are changed with a change in the speed ratio in a predetermined speed ratio range between a first speed ratio and a second speed ratio higher than the first speed ratio.

A transmission includes an input shaft, an output shaft, a first planetary gear mechanism, a second planetary gear mechanism, and a first variable device. The first planetary gear mechanism includes a first carrier connected to the input shaft, a first planetary gear connected to the first carrier, a first sun gear connected to the first planetary gear, and a ring gear connected to the first planetary gear. The second planetary gear mechanism includes a second sun gear connected to the first carrier, a second planetary gear connected to the second sun gear, and a second ring gear connected to the second planetary gear and connected to the first ring gear. The first variable device is connected to the first ring gear and the second ring gear to continuously change a speed ratio of the output shaft to the input shaft.

A variable drive system of a power system is disclosed. The variable drive system may include an engine gearset to transfer power from an engine output of an engine to a variable input driveshaft of the variable drive system. The variable drive system may include a generator gearset to transfer power, generated by the engine, to a generator driveshaft of a generator. The variable drive system may include a variable drive, coupled to the variable input driveshaft, to enable a gear ratio between engine output and the generator driveshaft to be adjustable, the variable input driveshaft being offset from at least one of the engine output or the generator driveshaft. The variable drive system may include a direct drive clutch to bypass variable power transfer through the variable drive and enable direct power transfer from the engine output to the generator driveshaft.

Methods and systems for a vehicle transmission are provided. An electromechanical transmission system includes, in one example, a power take-off (PTO) clutch configured to, in a first position, permit a motive power source shaft to solely drive a PTO. The PTO clutch is further configured to, in a second position, permit a first electric machine and a second electric machine to continuously vary a torque that is supplied to the PTO by the motive power source shaft.

A transmission includes an input shaft, an output shaft, a first planetary gear mechanism, a second planetary gear mechanism, and a first variable device. The first planetary gear mechanism includes a first carrier connected to the input shaft, a first planetary gear connected to the first carrier, a first sun gear connected to the first planetary gear, and a ring gear connected to the first planetary gear. The second planetary gear mechanism includes a second sun gear connected to the first carrier, a second planetary gear connected to the second sun gear, and a second ring gear connected to the second planetary gear and connected to the first ring gear. The first variable device is connected to the first ring gear and the second ring gear to continuously change a speed ratio of the output shaft to the input shaft.