Abstract: A work vehicle includes a human-machine interface configured to receive an input corresponding to a target rotation speed of a hydraulic motor. A rotation speed sensor is configured to detect a rotation speed of the hydraulic motor. A hydraulic control circuit is configured to control a hydraulic pressure of pilot oil to change a displacement volume of the hydraulic pump. Circuitry is configured to control a prime mover and the hydraulic control circuit. The circuitry is configured to obtain based on the target rotation speed, a reference value of a control parameter according to which the hydraulic control circuit is controlled, calculate a speed difference obtained by subtracting the target rotation speed from the rotation speed, calculate an offset value corresponding to the speed difference, and set the control parameter to a value obtained by adding the offset value to the reference value.

Abstract: A working machine includes: a left traveling motor; a right traveling motor; a left traveling pump including a first pressure-receiving portion and a second pressure-receiving portion; a right traveling pump including a third pressure-receiving portion and a fourth pressure-receiving portion; a traveling operation device configured to apply operation fluid to at least any one of the first, second, third and fourth pressure-receiving portions according to operation of a traveling operation member; an actuation valve configured to supply operation fluid to the traveling operation device, and change a pressure of the operation fluid supplied therefrom to the traveling operation device; a fourth fluid passage fluidly connecting the drainage to the second traveling fluid passage; and a fifth fluid passage fluidly connecting the drainage to the fourth traveling fluid passage.

Abstract: A work vehicle includes a processor and a memory storing instructions that when executed by the processor, cause the processor to perform operations. The operation includes determining an upper limit pressure that corresponds to an upper limit speed received via a second user interface and to a hydraulic pressure detected by a hydraulic pressure sensor, wherein the upper limit pressure increases as the hydraulic pressure detected by the hydraulic pressure sensor increases while the upper limit speed is maintained at a specific speed, and controlling a control valve to limit a traveling secondary pressure to not exceed the upper limit pressure that has been determined.

Abstract: A working machine includes: a first fluid passage fluidly connecting a traveling operation device to an actuation valve; a first traveling fluid passage; a second traveling fluid passage; a third traveling fluid passage; a fourth traveling fluid passage; a second fluid passage fluidly connecting the first fluid passage to the first traveling fluid passage; and a third fluid passage fluidly connecting the first fluid passage to the third traveling fluid passage. Each of the first, second, third, and fourth traveling fluid passages is configured so that operation fluid to be applied to a first, second, third, and fourth pressure-receiving portions flows through the first, second, third, and fourth traveling fluid passages, respectively, when a traveling operation member is operated.

Abstract: A work vehicle includes a primary pressure control valve configured to control a pilot primary pressure of pilot oil. A secondary pressure control valve is configured to control a pilot secondary pressure of the pilot oil. Control circuitry is configured to control a rotation speed of an engine according to a target rotation speed. The control circuitry is configured to control the primary pressure control valve and the secondary pressure control valve based on a first target value of the pilot primary pressure and a second target value of the pilot secondary pressure.

Abstract: A hydraulic system includes a prime mover, a variable displacement first hydraulic pump to be driven by the prime mover to deliver hydraulic fluid, a first hydraulic actuator to be driven by fluid delivered by the first hydraulic pump, a variable displacement second hydraulic pump to be driven by the prime mover to deliver hydraulic fluid, a second hydraulic actuator to be driven by fluid delivered by the second hydraulic pump, and first and second restrictors configured or programmed to restrict an output of the respective first and second hydraulic pumps based on a load on the prime mover. The first restrictor is configured or programmed to change an output restriction of the first hydraulic pump based on priority information about the first and second hydraulic actuators and/or the second restrictor is configured or programmed to change an output restriction of the second hydraulic pump based on the priority information.

Abstract: A working machine includes a traveling pump to be operated by power of a prime mover and deliver a hydraulic fluid; a traveling motor that rotates using the delivered hydraulic fluid; an operation valve that changes pilot pressure of a pilot fluid outputted to the traveling pump in response to operation of an operation member; an actuation valve that operates based on a control signal and changes primary pressure that is the pilot pressure of the pilot fluid supplied to the operation valve; a controller that controls opening of the actuation valve by outputting the control signal to the actuation valve; and a first detector that detects an actual number of revolutions of the traveling motor. The controller includes a changer that changes setting of the control signal such that the opening of the actuation valve increases as the actual number of revolutions of the traveling motor decreases.

Abstract: A working machine includes a prime mover, a traveling pump driven by power of the prime mover to deliver hydraulic fluid, a traveling motor rotated by the hydraulic fluid delivered from the traveling pump, an operation valve configured to change a pilot pressure of pilot fluid output therefrom to the traveling pump according to operation of an operation member, an actuation valve to be activated according to a control signal so as to change a primary pressure supplied to the operation valve, a controller to perform setting of the control signal to be output to the actuation valve, and a pressure detection device to detect a secondary pressure output from the operation valve. The controller includes a setting change unit to change, based on the primary pressure and the secondary pressure, the setting of the control signal to be output to the actuation valve.

Abstract: A method for controlling a work vehicle includes driving a first hydraulic pump and a second hydraulic pump by an engine to supply hydraulic fluid to a first hydraulic motor and a second hydraulic motor, respectively, to drive a first traveling device and a second traveling device, respectively. An operation state of a direction input device to operate a traveling direction of the work vehicle is detected. Based on the operation state detected, whether or not a traveling state of the work vehicle is a turning state. When it is determined that the traveling state is the turning state, a rotation command to decrease a target rotational speed of the engine from a first rotational speed to a second rotational speed is output.

Abstract: A work vehicle includes a primary pressure control valve configured to control a pilot primary pressure of pilot oil. A secondary pressure control valve is configured to control a pilot secondary pressure of the pilot oil. Control circuitry is configured to control a rotation speed of an engine according to a target rotation speed. The control circuitry is configured to control the primary pressure control valve and the secondary pressure control valve based on a first target value of the pilot primary pressure and a second target value of the pilot secondary pressure. The control circuitry is configured to reduce the first target value and the second target value such that the second target value is higher than the first target value when the rotation speed of the engine detected by a rotation speed sensor becomes lower than the target rotation speed by a predetermined speed difference or more.

Abstract: A work vehicle includes a primary pressure control valve configured to control a pilot primary pressure of pilot oil. A secondary pressure control valve is configured to control a pilot secondary pressure of the pilot oil. Control circuitry is configured to control a rotation speed of an engine according to a target rotation speed. The control circuitry is configured to control the primary pressure control valve and the secondary pressure control valve based on a first target value of the pilot primary pressure and a second target value of the pilot secondary pressure.

Abstract: A working machine includes a pump actuated by power from a prime mover to deliver hydraulic fluid, a working unit including a working device and an attachment to perform work upon actuation, by hydraulic fluid, of actuator(s) included in the working device and/or the attachment, a solenoid valve to change a flow rate of hydraulic fluid to the actuator(s) based on a control signal, a controller to input the control signal into the valve, an accelerator to input a target rotation speed of the prime mover, and a rotation speed sensor to detect an actual rotation speed of the prime mover. The controller is configured or programmed to, during high-load work, if a decrease in actual rotation speed relative to the target rotation speed reaches a threshold or greater, change the control signal based on the actual rotation speed to limit the flow rate of hydraulic fluid to the actuator(s).

Abstract: A working machine includes a controller that performs shift shock reduction control when shift-down switching from a second state to a first state, in which a motor speed can be increased up to a first maximum speed lower than a second maximum speed available in the second state, is performed. The controller includes a first processor configured to, based on a drop amount that is a difference between target and actual numbers of revolutions of a prime mover, compute a first reduction amount for reducing an amount of hydraulic fluid supply from a traveling pump to a traveling motor, a second processor configured to compute a second reduction amount based on a degree of straight traveling of a machine body, and a reduction controller configured to, based on the first or second reduction amount, whichever is larger in absolute value, perform the shift shock reduction control.

Abstract: A work vehicle includes a human-machine interface configured to receive an input corresponding to a target rotation speed of a hydraulic motor. A rotation speed sensor is configured to detect a rotation speed of the hydraulic motor. A hydraulic control circuit is configured to control a hydraulic pressure of pilot oil to change a displacement volume of the hydraulic pump. Circuitry is configured to control a prime mover and the hydraulic control circuit. The circuitry is configured to obtain based on the target rotation speed, a reference value of a control parameter according to which the hydraulic control circuit is controlled, calculate a speed difference obtained by subtracting the target rotation speed from the rotation speed, calculate an offset value corresponding to the speed difference, and set the control parameter to a value obtained by adding the offset value to the reference value.

Abstract: A working machine includes: a first fluid passage fluidly connecting a traveling operation device to an actuation valve; a first traveling fluid passage; a second traveling fluid passage; a third traveling fluid passage; a fourth traveling fluid passage; a second fluid passage fluidly connecting the first fluid passage to the first traveling fluid passage; and a third fluid passage fluidly connecting the first fluid passage to the third traveling fluid passage. Each of the first, second, third, and fourth traveling fluid passages is configured so that operation fluid to be applied to a first, second, third, and fourth pressure-receiving portions flows through the first, second, third, and fourth traveling fluid passages, respectively, when a traveling operation member is operated.

Abstract: A working machine includes a prime mover, a hydraulic pump driven by power of the prime mover, a cooler including a cooling fan rotated by either the power of the prime mover or hydraulic fluid delivered from the hydraulic pump, and a controller configured or programmed to perform a reduction control for reducing a target fan rotation speed that is a target rotation speed of the cooling fan in response to reduction of an actual prime mover rotation speed that is an actual rotation speed of the prime mover, and to perform, after the reduction control, a restoration control for restoring the target fan rotation speed. The controller is configured or programmed to make a difference between a reduction rate of the target fan rotation speed in the reduction control and an increase rate of the target fan rotation speed in the restoration control.

Abstract: A hydraulic system for a working machine includes: a first hydraulic pump; a first hydraulic device; a hydraulic fluid tank; a first discharge fluid passage to allow hydraulic fluid discharged from the first hydraulic device to flow into the tank; a second hydraulic pump to suck fluid from the tank through a suction fluid passage; a second hydraulic device in which difference between flow rate of fluid from the second hydraulic pump device and that of discharged fluid changes according to actuation; a second discharge fluid passage connected to a suction port of the first hydraulic pump and allowing fluid discharged from the second hydraulic device to flow into the first hydraulic pump; a connecting fluid passage branching from the second discharge fluid passage and connected to the suction fluid passage between the tank and the second hydraulic pump; a supplier to supply fluid to the second discharge fluid passage.

Abstract: A working machine includes a prime mover, a rotation-speed operation actuator, a rotation detector, a hydraulic pump, a hydraulic unit, an operation valve capable of changing a pilot pressure of a pilot fluid supplied from the hydraulic pump to the hydraulic unit in accordance with an operation of an operation member, an actuation valve operating in accordance with a control signal and capable of changing a primary pressure as the pilot pressure of the pilot fluid supplied from the hydraulic pump to the operation valve, and a controller that outputs the control signal based on a difference between target and actual rotation speeds to the actuation valve to control an opening thereof. The controller has a mode including calculating the control signal based on the difference, correcting the calculated control signal, and increasing or decreasing a target primary pressure value set in accordance with the control signal.

Abstract: A work vehicle includes a primary pressure control valve configured to control a pilot primary pressure of pilot oil. A secondary pressure control valve is configured to control a pilot secondary pressure of the pilot oil. Control circuitry is configured to control a rotation speed of an engine according to a target rotation speed. The control circuitry is configured to control the primary pressure control valve and the secondary pressure control valve based on a first target value of the pilot primary pressure and a second target value of the pilot secondary pressure. The control circuitry is configured to reduce the first target value and the second target value such that the second target value is higher than the first target value when the rotation speed of the engine detected by a rotation speed sensor becomes lower than the target rotation speed by a predetermined speed difference or more.

Abstract: A working machine includes a first traveling fluid passage connected to a first pressure-receiving portion, a second traveling fluid passage connected to a second pressure-receiving portion, a third traveling fluid passage connected to a third pressure-receiving portion, a fourth traveling fluid passage fluidly connected to a fourth pressure-receiving portion, and a connection fluid passage connecting at least two of the first, second, third and fourth pressure-receiving portions to each other. When a traveling operation member is operated, operation fluid flows to the first pressure receiving portion through the first traveling fluid passage, to the second pressure receiving portion through the second traveling fluid passage, to the third pressure receiving portion through the third traveling fluid passage, and to the fourth pressure receiving portion through the fourth traveling fluid passage.