A control system for a vehicle transmission is provided. The control system includes an electronic control unit. The electronic control unit is configured to, when control for engaging the at least one engaging device that switches power transmission to power transmission via a first power transmission mechanism and control for increasing hydraulic pressure that is applied to a continuously variable transmission are required, control the continuously variable transmission and the at least one engaging device so as to start control for engaging the at least one engaging device first and, after a lapse of a predetermined time from the start of control for engaging the at least one engaging device, start control for increasing hydraulic pressure that is applied to the continuously variable transmission.

A method of operating an agricultural vehicle including a range gearbox, an independent PTO system driven from an auxiliary drive shaft and a ground speed PTO system driven from an output shaft of the range gearbox. The method includes transferring torque from the auxiliary drive shaft to the output shaft of the range gear box via the independent PTO system and the ground speed PTO system while drive to the range gearbox is interrupted during a change in the range gear.

An automated manual transmission, comprising: a transmission control unit, a shift rod movable between a predetermined first position in which it engages a first gear combination of the transmission, a predetermined second position in which it engages a second gear combination of the transmission, and a predetermined neutral position in which it does not engage any gear, an actuator for moving the shift rod between the first position, the second position and the neutral position by applying a fluid pressure acting on the shift rod in response to signals from the transmission control unit, mechanical engagement means for maintaining the first and second positions of the shift rod without applying any fluid pressure by means of the actuator,
wherein the transmission is adapted to maintain the neutral position of the shift rod solely by applying fluid pressure acting on the shift rod.

An automated mechanical transmission for a vehicle includes a main gearbox assembly comprising a main shaft and being adapted to be shiftable between at least one engaged state and a neutral state; a split gearbox assembly comprising an input shaft and being adapted to be shiftable between a first engaged state, a second engaged state and a neutral state; a countershaft; a crawler gearbox assembly comprising a crawler gear engagement member which is adapted to selectively engage and disengage a crawler gear defining a torque path from the input shaft to the main gearbox assembly via the countershaft; a gearbox brake; and transmission control unit. The transmission is configured to be settable in an AMT neutral state defined by the main gearbox assembly being in the neutral state. When the transmission control unit obtains a request to engage the crawler gear from the AMT neutral state, the transmission control unit is configured to apply the gearbox brake so that a rotational speed of the countershaft is reduced to a first predetermined rotational speed which is higher than a zero rotational speed; and when the first predetermined rotational speed is reached, release the gearbox brake, set the split gearbox assembly to the neutral state and engage the crawler gear by the crawler gear engagement member.

A method of operating an agricultural vehicle including a range gearbox, an independent PTO system driven from an auxiliary drive shaft and a ground speed PTO system driven from an output shaft of the range gearbox. The method includes transferring torque from the auxiliary drive shaft to the output shaft of the range gear box via the independent PTO system and the ground speed PTO system while drive to the range gearbox is interrupted during a change in the range gear.

The present invention provides a hybrid powertrain comprising an internal combustion engine (ICE), a transmission (2), a first electric motor (4a) and a second electric motor (4b), wherein the transmission comprises an input shaft (1) to which the ICE is connected via a main clutch (3), an output shaft (6) and a gear assembly providing at least two different gear ratios that may be selected for transfer of mechanical power from the input shaft (1) to the output shaft (6), the first electric motor (4a) is connected to the input shaft (1) via a first gear (i.sub.x), such that torque and rotation may be transferred between the first electric motor and the input shaft, and the second electric motor (4b) is connected to the input shaft (1) via a first clutch (5a) and the first gear (i.sub.x), such that torque and rotation may be transferred between the second electric motor (4b) and the input shaft (1), and connected to the output shaft (6) via a second clutch (5b) and a second gear (i.sub.y), such that torque and rotation may be transferred between the second electric motor (4b) and the output shaft (6), wherein the first electric motor (4a) is connected to the second electric motor (4b) via the first clutch (5a), and the first electric motor (4a), the second electric motor (4b), the first clutch (5a) and the second clutch (5b) form parts of a torque transfer path bypassing the at least two different gear ratios, the torque transfer path arranged to transfer torque from the input shaft (1) to the output shaft (6) during a gearshift.

A clutch includes a clutch disk that rotates by receiving motive power from an engine and a clutch plate switched between an engaged state in which it is engaged with the clutch disk and a disengaged state in which it is not engaged with the clutch disk. A controller calculates a coefficient of friction μ between the clutch disk and the clutch plate based on a time period Δt elapsed from a first time point when the number of relative rotations of the clutch disk and the clutch plate attains to a first number of rotations to a second time point when a second number of rotations smaller than the first number of rotations is attained, in a state in which the clutch disk rotates while transfer of motive power from the engine to the clutch disk is cut off and in the engaged state.

A speed-changing device (21) is provided with an input shaft (22), an output shaft (23), a planetary gear mechanism (29), a first variator (33), a second variator (34), and a controller (25). The planetary gear mechanism (29) is configured to include a carrier (29A) connected to the input shaft (22), a first sun gear (29B) connected to the first variator (33), and a second sun gear (29C) connected to the output shaft (23). The second variator (34) transmits power transmitted from the first variator (33) to the output shaft (23), or transmits power transmitted from the output shaft (23) to the first variator (33). The controller (25) changes the rotation speed of the first variator (33), thereby changing the rotation speed of the output shaft (23) in relation to the rotation speed of the input shaft (22).

Described herein are systems and techniques for utilizing a powered axle that includes a plurality of transmissions. The powered axle may include separate transmissions to power wheels on opposite ends of the powered axle. Each transmission of the powered axle may be operated independently of the other transmission. As such, the plurality of transmissions of the powered axle may be shifted independently of each other. Various control schemes may be provided for operation of such transmissions.

A speed-changing device (21) is provided with an input shaft (22), an output shaft (23), a planetary gear mechanism (29), a first variator (33), a second variator (34), and a controller (25). The planetary gear mechanism (29) is configured to include a carrier (29A) connected to the input shaft (22), a first sun gear (29B) connected to the first variator (33), and a second sun gear (29C) connected to the output shaft (23). The second variator (34) transmits power transmitted from the first variator (33) to the output shaft (23), or transmits power transmitted from the output shaft (23) to the first variator (33). The controller (25) changes the rotation speed of the first variator (33), thereby changing the rotation speed of the output shaft (23) in relation to the rotation speed of the input shaft (22).