Methods and systems for transmission control are provided. In one example, a transmission system operating method includes maintaining a displacement set-point of a variable displacement hydraulic motor in a hydrostatic assembly within a working zone, where at least a portion of a boundary of the working zone is determined based on a torque constraint of the hydrostatic assembly. The transmission system includes the hydrostatic assembly that includes the hydraulic motor that is hydraulically coupled in parallel with a variable displacement hydraulic pump and a gearbox mechanically coupled to the hydrostatic assembly and including one or more clutches.

A work vehicle includes a hydrostatic stepless speed changer device configured to speed-change driving power of an engine steplessly, a plurality of planetary gear speed changer devices configured to speed-change the driving power speed-changed by the stepless speed changer device, a plurality of clutch mechanisms corresponding to the plurality of planetary gear speed changer devices in order to take off the driving powers from these plurality of planetary gear speed changer devices individually, and a traveling speed changer device for speed-changing and transmitting the driving powers transmitted from the plurality of clutch mechanisms to a traveling mechanism. The plurality of planetary gear speed changer devices the plurality of clutch mechanisms, and the traveling speed changer device are accommodated in a transmission case.

A hydro-mechanical transmission device with a dual-clutch transmission includes an input mechanism, a pump-controlled motor mechanism, an odd-numbered gear transmission mechanism, an even-numbered gear transmission mechanism, an output mechanism, and a jackshaft. The input mechanism is connected to the odd-numbered gear transmission mechanism and the even-numbered gear transmission mechanism that are connected in parallel, and is connected to an input end of the pump-controlled motor mechanism. An output end of the pump-controlled motor mechanism is connected, through the jackshaft, to the odd-numbered gear transmission mechanism and the even-numbered gear transmission mechanism that are connected in parallel, and is connected to the output mechanism. Switching among hydraulic transmission, hydro-mechanical transmission, and mechanical transmission modes between the input mechanism and the output mechanism is implemented by controlling combination and engagement/disengagement of clutches and a brake.

A transmission system for a vehicle having a belt drive transmission. The belt drive has an adjustable input and output ratio, where the output of the belt drive is provided as a first input to a differential coupling. A further rotating connection is provided as a second input to the differential coupling, so that the output of the differential coupling is arranged as the output of the transmission system. Accordingly, the transmission output is based on the aggregate sum of the rotation of the first and second inputs to the differential coupling, wherein adjustment of the input and output ratio of the belt drive allows for a continuously variable transmission system.

An electronic controller for a variable ratio transmission and an electronically controllable variable ratio transmission including a variator or other CVT are described herein. The electronic controller can be configured to receive input signals indicative of parameters associated with an engine coupled to the transmission. The electronic controller can also receive one or more control inputs. The electronic controller can determine an active range and an active variator mode based on the input signals and control inputs. The electronic controller can control a final drive ratio of the variable ratio transmission by controlling one or more electronic solenoids that control the ratios of one or more portions of the variable ratio transmission.

Systems and methods for controlling transmissions having CVTs are disclosed with multiple modes and gearing arrangements for range enhancements, where embodiments include synchronous shifting to allow the transmission to achieve a continuous range of transmission ratios, while minimizing “empty” cycling of the CVT during mode shifts. Embodiments provide for wide ratio range and performance and efficiency flexibility, while maximizing CVT usage through synchronous shifting.

A power split transmission for a work vehicle includes at least one drivable transmission input shaft, a power distribution module, a rotational speed variator having a variator output shaft, a transmission module operatively connected both to the transmission input shaft and the variator output shaft, and a transmission output shaft. The transmission module includes at least two transmission auxiliary shafts each of which includes at least one summation transmission for combining power introduced via the transmission input shaft and the variator output shaft. The transmission module includes at least one power shift stage via which the transmission auxiliary shafts are selectively connected to the transmission output shaft. A continuously variable transmission ratio is produced between the transmission input shaft and transmission output shaft.

Aspects of the present disclosure relate to a powertrain assembly including a continuously variable transmission and, in some examples, a clutch. The clutch may be operably coupled between a prime mover and the continuously variable transmission. Additionally, or alternatively, a clutch may be operable coupled after or downstream of the continuously variable transmission. Aspects of the powertrain assembly may be controlled to provide starting-clutch functionality, to provide torque-limiting functionality, and/or to adapt operation of the powertrain for any of a variety of conditions.

A traveling transmission device of a tractor including a transmission case to which power from an engine is inputted via an input shaft, a speed changer transmission section provided inside the transmission case and configured to input power from the input shaft and to speed-change the inputted power and output it, and a rear wheel differential mechanism provided inside the transmission case and configured to input power outputted from the speed changer transmission section and transmit the inputted power to left and right rear wheels. The speed changer transmission section includes a plurality of speed changer sections configured to speed-change power from the input shaft by a gear coupling mechanism and a multiple-disc clutch and output it, and, inside the transmission case, an oil feeding pipe extends upwardly of the speed changer transmission section and a discharge nozzle connects to respective portions of the plurality of speed changer sections.

Methods and systems for a hydromechanical transmission are provided herein. In one example, the transmission operating method includes asynchronously shifting between a first pair of drive ranges in the transmission via operation of two clutches and a variable displacement hydraulic pump in a hydrostatic assembly. In the method, asynchronously shifting between the two drive ranges includes a plurality of phases that include a swiveling phase where a speed of the hydrostatic assembly is inverted.