Komatsu Corporation

Atsushi Shirao

Masanori Ikari

Shinichi Kitao

Takeshi Kamimae

Minoru Wada

Takahisa Oasa

Toru Shiina

Yutaka Tanaka

Hirotaka Takahashi

Hidehiro Hashimoto

Katsuyuki Morimoto

Yuuya Kusumoto

Satoshi Isejima

Shigeo Hashimoto

Motoki Ohba

Isao Ueno

Takuya Mori

A mode selecting unit is configured to generate an operation signal indicating one control mode selected from a plurality of control modes including a predetermined first mode and a second mode in which a traction force is controlled to be smaller than a traction force in the first mode. A controller is configured to obtain the operation signal from the mode selecting unit and control a drivetrain in accordance with the selected control mode. The controller is configured to start controlling the drivetrain in the second mode in starting of a vehicle.

Wheel loader and control method thereof

A work vehicle is provided with an engine, a hydraulic pump, a movement hydraulic motor, an acceleration operation member, and a control section. The hydraulic pump is driven by the engine. The movement hydraulic motor is driven by hydraulic fluid which is discharged from the hydraulic pump. The acceleration operation member is operated in order to set a target rotation speed for the engine. The control section is configured to perform traction control where the maximum traction force is reduced by limiting the displacement of the movement hydraulic motor to an upper limit displacement which is smaller than the maximum displacement. The control section increases the upper limit displacement of the movement hydraulic motor according to an increase in the operation amount of the acceleration operation member or the engine rotation speed in the traction control.

Work vehicle and work vehicle control method

A control unit of the work vehicle is configured to set an upper limit of a throttle opening degree based on third throttle upper limit information when a work vehicle is performing excavation work and when work implement is not in use, to set the upper limit based on the second throttle upper limit information when the work vehicle is performing excavation work and when the work implement is in use, and to set the upper limit based on the first throttle upper limit information when an angle of a boom is equal to or greater than a predetermined angle, even when the work vehicle is performing excavation work. The second throttle upper limit information specifies a lower upper limit than the first throttle upper limit information, and the third throttle upper limit information specifies a lower upper limit than the second throttle upper limit information.

Work vehicle and method for controlling work vehicle

A tractive force control part of a wheel loader is configured to perform a tractive force control to reduce a maximum tractive force. The tractive force control part is further configured to reduce the maximum tractive force when determination conditions including, while a working implement is performing excavation operation, that the working implement is in a raising hydraulic stall condition and that a drive circuit pressure is greater than or equal to a predetermined hydraulic pressure threshold are satisfied during the tractive force control.

Wheel loader and method for controlling a wheel loader

A traction force control section of a wheel loader, when the determination conditions are satisfied during traction force control, increases the maximum traction force. The determination conditions include that the wheel loader is performing an excavation operation, that the vehicle speed is less than or equal to a prescribed speed threshold value, that the amount of operation of the accelerator operating member is equal to or more than a prescribed accelerator threshold value, and that the amount of operation of the inching operating member is less than or equal to a prescribed inching operation threshold value.

Wheel loader and method for controlling wheel loader

A work vehicle includes a pair of booms, a link mechanism and a control unit. The booms are attached to a front part of a vehicle body in an upwardly and downwardly rotatable state. The link mechanism couples a working unit to tips of the booms. The link mechanism is configured to keep the working unit in a posture generally parallel to the ground without rotating the working unit with respect to the ground while the booms are elevated from a position where the working unit is disposed on the ground when the working unit is a fork. The control unit is configured to execute a tilt angle adjusting control for the working unit in accordance with variation in an angle of the booms while the booms are elevated when a tilt angle of the working unit is greater than or equal to a predetermined threshold.

Work vehicle

A control apparatus of a working vehicle including a hydraulic pump driven by an engine and two hydraulic motors connected in parallel to the hydraulic pump, a clutch being released or engaged so that a power is transmitted to one of the hydraulic motors via the clutch, includes: a load detection unit determining a load of the working vehicle from a throttle output amount and an engine speed of the engine; and a control unit reducing a pump injection amount of the hydraulic pump under an upper limit injection amount of the hydraulic pump predetermined based on the load at a time of release shift control of the clutch and increasing a pump injection amount of the hydraulic pump under a lower limit injection amount of the hydraulic pump predetermined based on the load at a time of engagement shift control of the clutch.

Control apparatus of working vehicle and control method thereof

A wheel loader includes a vehicle body, a work implement, a link mechanism and a control section. The work implement has a boom a work tool. The link mechanism is configured and arranged to change a relative angle of the work tool with respect to the boom when the boom is rotated upward, such that an amount of variation of an angle of the work tool with respect to a horizontal direction is less than an amount of variation of an angle of the work tool with respect to the horizontal direction when the boom is rotated upward while the work tool is at a fixed relative angle with respect to the boom. The control section is configured to execute an auto tilt control that causes the work tool to rotate upward when the boom is rotated upward within an angular range below the horizontal direction during excavation.

Wheel loader

A wheel loader () is designed so that when a specific first condition is met for vehicle speed, accelerator opening, engine speed, and HST pressure, the engine absorption torque curve of an HST pump () is switched to shift the matching point from the low-engine speed side to the high-engine speed side. On the other hand, if a second condition is met for vehicle speed and HST pressure, control is performed so that the absorption torque curve of the HST pump () is returned from the high-engine speed side to the low-engine speed side.

Construction vehicle

A pump displacement control cylinder is configured to control the displacement of a hydraulic pump according to pressure of hydraulic fluid and switches the discharge direction of the hydraulic fluid from the hydraulic pump according to the supply direction of the hydraulic fluid to the pump displacement control cylinder. A forward and backward progression switching valve is configured to switch the supply direction of the hydraulic fluid to the pump displacement control cylinder. A pressure control valve is configured to control the pressure of the hydraulic fluid supplied to the pump displacement control cylinder according to a command value input to the pressure control valve. A control section is configured to execute pump shuttle control which reduces the command value to the pressure control valve when switching between forward and backward progression using a forward and backward progression operation member.

A traction force control section of a wheel loader, when the determination conditions are satisfied during traction force control, increases the maximum traction force. The determination conditions include that the aspect of operation is excavation, that the vehicle speed is less than or equal to a prescribed speed threshold value, that the amount of operation of the accelerator operating member is equal to or more than a prescribed accelerator threshold value, and that the amount of operation of the inching operating member is less than or equal to a prescribed inching operation threshold value.

A working vehicle includes an engine, a hydraulic pump, a first hydraulic motor, a vehicle speed detecting unit, a parking brake, a parking brake operating member and a control unit. The control unit is configured to determine whether the vehicle speed is equal to or greater than a predetermined threshold when the parking brake operating member is operated. The control unit is configured to execute a brake control that decreases a displacement of the first hydraulic pump and increases a displacement of the first hydraulic motor without activating the parking brake when the vehicle speed is equal to or greater than the predetermined threshold in a state when the vehicle is traveling, and to activate the parking brake when the vehicle speed falls below the predetermined threshold.

Work vehicle and control method for work vehicle

A work vehicle includes an engine, a throttle opening degree setting unit, first and second hydraulic pumps driven by the engine, a travel hydraulic motor driven by hydraulic fluid discharged from the first hydraulic pump, a work implement driven by hydraulic fluid discharged from the second hydraulic pump. A first control unit is configured to determine a work phase of the work implement and to set an upper limit for the throttle opening degree in accordance with the work phase. A second control unit is configured to control output of the engine based on the smaller of the throttle opening degree set by the throttle opening degree setting unit and the throttle opening degree set by the first control unit.

A traction force control section of a wheel loader reduces maximum traction force to below the maximum traction force with traction force control in an off state when the traction force control is in an on state. The traction force control section increases the maximum traction force when determination conditions are satisfied with the traction force control in the on state. The determination conditions include that the work situation is digging, that the operation amount of the acceleration operation member is the predetermined operation threshold or more, and that a boom angle is the predetermined angle threshold or more.

Wheel loader and wheel loader control method

In a work vehicle, a control section increases the displacement of a hydraulic motor for travel when the drive circuit pressure becomes larger than a target pressure determined according to the engine rotational speed, and reduces the displacement of the hydraulic motor when the drive circuit pressure becomes smaller than the target pressure. The control section increases the target pressure of the hydraulic motor for travel when changing the matching point of the absorption torque curve of the hydraulic pump with respect to the output torque curve of the engine.

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Komatsu, Japan

Atsushi Shirao