Komatsu Corporation

Jun Koizumi

Takeo Yamada

Shotaro Ishii

Satoshi Asami

Takahisa Oasa

Ai Haginiwa

Masahiro Minato

A work vehicle includes a drive source, a travel device, a hydraulic pump, a work implement, a traction force detector, a lift force detector and a controller. The traction force detector is configured to detect traction force of the work vehicle. The lift force detector is configured to detect lift force for raising the work implement. The controller is configured to compare a predetermined threshold and a ratio between the lift force and the traction force, and to execute traction force reduction control for reducing the traction force when an increase in the lift force is required.

Work vehicle and work vehicle control method

A work vehicle includes a controller. The controller is configured to determine whether low-load conditions indicating that the work vehicle is in a low-load state are satisfied. The controller is configured to control an engine so that an upper limit value of an output torque of the engine when the low-load conditions are satisfied is made less than when the low-load conditions are not satisfied. Also, the controller is configured to vary a reduction amount of the upper limit value of the output torque of the engine when the low-load conditions are satisfied, in accordance with variation in at least one of vehicle speed, vehicle acceleration, and engine-rotation-speed acceleration, and in accordance with variation in engine rotation speed.

A hydraulic traveling vehicle includes a right-travel motor a left-travel motor, a hydraulic pump, a merging/diverging valve and a travel switching unit. The merging/diverging valve is configured to switch between merging and separating a first hydraulic circuit and a second hydraulic circuit. The travel switching unit is configured to switch between a state where sharp turning takes place as a result of one of the right-travel motor and the left-travel motor being stopped and the other being driven, with the merging/diverging valve being in a merging state, and a state where gentle turning takes place as a result of the right-travel motor and the left-travel motor being driven at different rotational speeds, with the merging/diverging valve being in a diverging state.

Hydraulic traveling vehicle

With a hydraulic traveling vehicle, a controller is configured and arranged to switch a merging/diverging valve to a merging state when a working equipment is driven with the merging/diverging valve being in a diverging state and with turning of the hydraulic traveling vehicle being carried out, and when a required flow rate parameter for pressurized oil of the working equipment is greater than or equal to a prescribed threshold value, and to maintain the merging/diverging valve in the diverging state when the required flow rate parameter is less than the prescribed threshold value.

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Hadano, Japan

Jun Koizumi