Abstract: A hybrid work vehicle includes a traveling device and a control device. The traveling device includes first and second rotary electric machines, an internal-combustion engine, a power transmission device transmitting power output from the engine to a vehicle wheel through at least the first and second machines, a third rotary electric machine applying power to at least one of the first and second machines, and a braking device braking the vehicle wheel. The control device executes a first control of applying the power of the third machine to at least one of the first and second machines and a second control of canceling the first control when a vehicle speed of the traveling device becomes or exceeds a speed threshold value and continuously applies the power from the third machine when a braking force of the braking device is larger than a braking force threshold value during the second control.

Abstract: The work implement requirement determination unit determines a work implement required horsepower on the basis of an operation amount of a work implement operating member and a hydraulic pressure of a hydraulic pump. A transmission requirement determination unit determines a transmission required horsepower on the basis of a vehicle speed and the operation amount of the accelerator operating member. An engine requirement determination unit determines an engine required horsepower on the basis of the work implement required horsepower and the transmission required horsepower. The required throttle determination unit determines a required throttle value based on an engine requirement.

Abstract: A hybrid work vehicle includes a traveling device and a control device. The traveling device includes first and second rotary electric machines, an internal-combustion engine, a power transmission device transmitting power output from the engine to a vehicle wheel through at least the first and second machines, a third rotary electric machine applying power to at least one of the first and second machines, and a braking device braking the vehicle wheel. The control device executes a first control of applying the power of the third machine to at least one of the first and second machines and a second control of canceling the first control when a vehicle speed of the traveling device becomes or exceeds a speed threshold value and continuously applies the power from the third machine when a braking force of the braking device is larger than a braking force threshold value during the second control.

Abstract: A gear mechanism of a power train includes first and second planetary gear mechanisms, which respectively include first to third rotating elements and fourth to sixth rotating elements which are each different to each other. The transmission section transfers the drive force of the second rotating element to the fourth rotating element. A rotating shaft fixing section of a power train integrally operates the rotating shafts of the third and fifth rotating elements. A variable transmission section of a power train includes an input section where drive force is input and an output section configured to output drive force equal to or less than the input drive force. A drive force conversion control section of a controller controls the variable transmission section to enable the output of the engine to be converted to an appropriate drive force and the converted drive force to be transferred to the output shaft.

Abstract: A control unit embedded in a work vehicle includes a clutch controlling unit and a motor controlling unit. The clutch controlling unit is configured to disengage a first clutch in a condition that the first clutch is engaged and a second clutch is disengaged, when a first moving direction inputted through a forward/rearward movement switch operating device as an instruction of the operator and a second moving direction determined based on a vehicle speed detected by a vehicle speed detecting unit are different from each other, and in addition, when and the vehicle speed falls in a preliminarily set first range. The motor controlling unit is configured to control a motor to reduce a relative rotational speed of the second clutch after the first clutch is disengaged.

Abstract: A power transmission device includes an input shaft, an output shaft, a gear mechanism, an energy-generating motor, a first clutch, and a locking device. The energy storage unit is configured to store the energy generated by the energy-generating motor. The gear mechanism includes a planetary gear mechanism, which includes a first rotation element, a second rotation element, and a third rotation element, which are mutually different. The first clutch is provided in the power transmission route between the engine and the first rotation element. The locking device locks or releases the second rotation element. The energy-generating motor is connected to the third rotation element. A controller locks the second rotation element, converges the rotation speeds of two rotation shafts in the first clutch to cause the first clutch to engage, and rotates the energy-generating motor using drive power from the engine to thereby accumulate energy in the energy storage unit.

Abstract: A power transmission device of a work vehicle includes a generator, a motor, and an energy storage unit. The energy storage unit stores electricity generated by the generator. A forward/backward travel switch operation device receives an instruction for forward or backward travel from an operator. A vehicle speed detection unit detects the speed of the vehicle. A control unit includes an energy management requirement determination unit. The energy management requirement determination unit determines, on the basis of the difference between a target electricity storage amount and a current electricity storage amount in the energy storage unit, the energy management required power required by the power transmission device for charging the energy storage unit. The energy management requirement determination unit increases the target electricity storage amount when a first travel direction according to the instruction and a second travel direction determined from the vehicle speed are different.

Abstract: The power-transmission device has an input shaft, an output shaft, a gear mechanism, and a motor. The gear mechanism includes a plurality of planetary gear mechanisms and a mode-switching mechanism, and transmits the rotations of the input shaft to the output shaft. The mode-switching mechanism selectively switches the drive-power transmission path of the power-transmission device between a plurality of modes. The motor is connected to the rotating elements of the planetary gear mechanisms. A target-input-torque determination unit determines the target input torque, which is a target value for the torque to be inputted to the power-transmission device. The target-output-torque determination unit determines the target output torque, which is a target value for the torque to be outputted from the power-transmission device. The command-torque determination unit uses the torque balance information to determine torque commands to the motor from the target input torque and the target output torque.

Abstract: A controller includes a neutral control determination unit, a forward-reverse clutch control unit, and a commanded torque setting unit. The neutral control determination unit executes quasi-neutral control when a quasi-neutral control determination condition is satisfied. The quasi-neutral control determination condition includes cases where the forward-reverse operation member is in the neutral position. The forward-reverse clutch control unit keeps the forward-travel clutch or the reverse-travel clutch engaged during the quasi-neutral control. During quasi-neutral control, the commanded torque setting unit determines a commanded torque sent to the motor so that a neutral state is set where the output torque from the power transmission device to the travel device is kept at a prescribed value regardless of the drive power output from the engine.

Abstract: A power transmission device includes a gear mechanism, a predetermined controlling rotation element, an energy-generating motor, and a connected motor connected to the controlling rotation element. The energy storage unit is configured to store the energy generated by the energy-generating motor. The gear mechanism includes a first planetary gear mechanism, which includes a first rotation element, a second rotation element, and a third rotation element, which are mutually different. The engine is connected to the first rotation element. The energy-generating motor is connected to the third rotation element. The controlling rotation element may be at least one of the rotation elements between the second rotation element and the connected motor. The controller controls the locking of the controlling rotation element to thereby lock the second rotation element, and causes the energy-generating motor to rotate using the drive power from the engine to thereby accumulate energy in the energy storage unit.

Abstract: A control unit embedded in a work vehicle includes a clutch controlling unit and a motor controlling unit. The clutch controlling unit is configured to disengage a first clutch in a condition that the first clutch is engaged and a second clutch is disengaged, when a first moving direction inputted through a forward/rearward movement switch operating device as an instruction of the operator and a second moving direction determined based on a vehicle speed detected by a vehicle speed detecting unit are different from each other, and in addition, when and the vehicle speed falls in a preliminarily set first range. The motor controlling unit is configured to control a motor to reduce a relative rotational speed of the second clutch after the first clutch is disengaged.

Abstract: A power transmission device of a work vehicle includes a generator, a motor, and an energy storage unit. The energy storage unit stores electricity generated by the generator. A forward/backward travel switch operation device receives an instruction for forward or backward travel from an operator. A vehicle speed detection unit detects the speed of the vehicle. A control unit includes an energy management requirement determination unit. The energy management requirement determination unit determines, on the basis of the difference between a target electricity storage amount and a current electricity storage amount in the energy storage unit, the energy management required power required by the power transmission device for charging the energy storage unit. The energy management requirement determination unit increases the target electricity storage amount when a first travel direction according to the instruction and a second travel direction determined from the vehicle speed are different.

Abstract: A power transmission device includes a gear mechanism, a predetermined controlling rotation element, an energy-generating motor, and a connected motor connected to the controlling rotation element. The energy storage unit is configured to store the energy generated by the energy-generating motor. The gear mechanism includes a first planetary gear mechanism, which includes a first rotation element, a second rotation element, and a third rotation element, which are mutually different. The engine is connected to the first rotation element. The energy-generating motor is connected to the third rotation element. The controlling rotation element may be at least one of the rotation elements between the second rotation element and the connected motor. The controller controls the locking of the controlling rotation element to thereby lock the second rotation element, and causes the energy-generating motor to rotate using the drive power from the engine to thereby accumulate energy in the energy storage unit.

Abstract: A gear mechanism of a power train includes first and second planetary gear mechanisms, which respectively include first to third rotating elements and fourth to sixth rotating elements which are each different to each other. The transmission section transfers the drive force of the second rotating element to the fourth rotating element. A rotating shaft fixing section of a power train integrally operates the rotating shafts of the third and fifth rotating elements. A variable transmission section of a power train includes an input section where drive force is input and an output section configured to output drive force equal to or less than the input drive force. A drive force conversion control section of a controller controls the variable transmission section to enable the output of the engine to be converted to an appropriate drive force and the converted drive force to be transferred to the output shaft.

Abstract: A power transmission device includes an input shaft, an output shaft, a gear mechanism, an energy-generating motor, a first clutch, and a locking device. The energy storage unit is configured to store the energy generated by the energy-generating motor. The gear mechanism includes a planetary gear mechanism, which includes a first rotation element, a second rotation element, and a third rotation element, which are mutually different. The first clutch is provided in the power transmission route between the engine and the first rotation element. The locking device locks or releases the second rotation element. The energy-generating motor is connected to the third rotation element. A controller locks the second rotation element, converges the rotation speeds of two rotation shafts in the first clutch to cause the first clutch to engage, and rotates the energy-generating motor using the drive power from the engine to thereby accumulate energy in the energy storage unit.

Abstract: The target input shaft torque determination unit determines a target input shaft torque. The target output shaft torque determination unit determines a target output shaft torque so that a deceleration force for decelerating the vehicle is generated on the output shaft of the power transmission device in a state in which connection and disconnection states of the forward travel clutch and the reverse travel clutch are maintained at the state before the start of the shuttle action when the shuttle action is started. The torque-balance information is stored in a storage unit and defines a relationship between the target input shaft torque and the target output shaft torque to achieve a balance of the torques of a power transmission device. The command torque determination unit uses the torque-balance information to determine torque commands for the motor from the target input shaft torque and the target output shaft torque.

Abstract: A controller includes a neutral control determination unit, a forward-reverse clutch control unit, and a commanded torque setting unit. The neutral control determination unit executes quasi-neutral control when a quasi-neutral control determination condition is satisfied. The quasi-neutral control determination condition includes cases where the forward-reverse operation member is in the neutral position. The forward-reverse clutch control unit keeps the forward-travel clutch or the reverse-travel clutch engaged during the quasi-neutral control. During quasi-neutral control, the commanded torque setting unit determines a commanded torque sent to the motor so that a neutral state is set where the output torque from the power transmission device to the travel device is kept at a prescribed value regardless of the drive power output from the engine.

Abstract: In a work vehicle, a controller controls an engine based on an engine torque curve for defining a relationship between an engine speed, an engine output torque, and an operation amount of an accelerator operation member. The controller controls the engine based on a first engine torque curve during torque conversion travel. The controller controls the engine based on a second engine torque curve during lockup travel. The engine output torque of the second engine torque curve is less than the engine output torque of the first engine torque curve in at least a portion of a range of the engine speed when at least the operation amount of the accelerator operation member is a predetermined operation amount that is less than a maximum operation amount.

Abstract: A target-input-torque determination unit determines the target input torque on the basis of the transmission required horsepower. The target input torque is a target value for the torque to be inputted to a power-transmission device. A target-output-torque determination unit determines the target output torque, which is a target value for the torque to be outputted by the power-transmission device. A command-torque determination unit uses torque-balance information to determine command torque for the motor from the target input torque and the target output torque. The target-input-torque determination unit determines the upper limit of the target input torque on the basis of an upper-limit-target-input-torque line and the engine rotation speed. The upper-limit-target-input-torque line sets a value smaller than the target output torque of the engine determined using the engine required horsepower and the engine rotation speed for the upper-limit value of the target input torque.

Abstract: When a clutch is in the disengaged state, the predicted engagement time determining unit determines a predicted engagement time. The predicted engagement time is the predicted value for the time required from the beginning of the clutch engagement until engagement is complete. The speed ratio parameter estimating unit determines an estimated value for a speed ratio parameter after the elapse of the predicted engagement time from the current point in time. When the estimated value for the speed ratio parameter reaches a mode-switching threshold value, a clutch control unit outputs a clutch command signal for causing the clutch to engage.