Komatsu Corporation

Nobumasa Takamatsu

Shuuji Hori

Mitsumasa Akashi

Hiroyuki Chikugo

Shuki Akushichi

Akira Hasebe

Kota Imanishi

Nobuo Ushikubo

Yasuhiro Yamane

A steering device for a wheel loader includes a handle for steering, a lever for steering, a steering cylinder, a steering valve that controls a direction of operating fluid to the steering cylinder, and a pump that supplies operating fluid to the steering cylinder via the steering valve. The steering device further includes a handle control valve that controls the supply direction of the operating fluid according the handle, a lever electromagnetic control valve that controls the supply direction of operating fluid according to the lever, and a handle prioritization valve that shuts off a pilot hydraulic pressure supplied from the lever electromagnetic control valve to the steering valve according to a pressure produced by operating fluid flowing through the handle control valve when the handle is operated. The handle prioritization valve includes a switching valve and a priority control valve switchable between a handle stage and a lever stage.

Steering device for wheel loader

A steering device for a wheel loader includes a handle for steering, a lever for steering, a steering cylinder, a steering valve that controls a direction of operating fluid to the steering cylinder, and a pump that supplies operating fluid to the steering cylinder via the steering valve. The steering device further includes a handle control valve that controls the supply direction of the operating fluid according the handle, a lever electromagnetic control valve that controls the supply direction of operating fluid according to the lever, and a handle prioritization valve that shuts off a pilot hydraulic pressure supplied from the lever electromagnetic control valve to the steering valve according to a pressure produced by operating fluid flowing through the handle control valve when the handle is operated. Communication between the lever electromagnetic control valve and the steering valve is allowed when only the lever electromagnetic control valve is operated.

A steering device for a wheel loader includes a handle for steering, a lever for steering, a steering cylinder, a steering valve that controls a direction of operating fluid to the steering cylinder, a pump that supplies operating fluid to the steering cylinder via the steering valve, and a return oil passage connected to a tank. The steering device further includes a handle control valve that controls the supply direction of the operating fluid according the handle, a lever electromagnetic control valve that controls the supply direction of operating fluid according to the lever, and a handle prioritization valve that shuts off a pilot hydraulic pressure supplied from the lever electromagnetic control valve to the steering valve according to a pressure produced by operating fluid flowing through the handle control valve when the handle is operated. The handle prioritization valve includes a throttle arranged in the return oil passage.

A steering device for a wheel loader includes a rotatable handle, a tiltable lever, a steering cylinder, a steering valve, a pump, a handle control valve, a lever control valve, and a handle prioritization valve. The steering valve controls a supply direction of operating fluid to the steering cylinder with pilot hydraulic pressure. The pump supplies operating fluid to the steering cylinder via the steering valve. The handle and lever control valves supply pilot hydraulic pressure to control the supply direction to the steering valve according to handle rotation and lever tilt, respectively. The handle prioritization valve shuts off the pilot hydraulic pressure supplied from the lever control valve to the steering valve according to a differential pressure or an absolute pressure in a hydraulic circuit produced due to operating fluid flowing through the handle control valve when the handle is operated.

A frame locking bar is supported pivotably with respect to a rear body. The frame locking bar is constructed to be able to lock an articulated structure by fixing a front body and the rear body to each other to thereby prevent swing thereof. A fixing mechanism is constructed to be able to position this frame locking bar at a prescribed pivoted position in a cantilevered state. At the positioned prescribed pivoted position, when viewed from above, a foot mount is located outside a side surface of a driver's compartment. Thus, a wheel loader capable of locking an articulated mechanism and allowing easy and highly safe services at a high position is obtained.

Wheel loader

A working vehicle including a power transmission system capable of surely preventing a slip is provided. For this purpose, the working vehicle is a working vehicle having a modulating clutch ( ) which flexibly changes traveling power transmitted from an engine ( ) to a torque converter ( ), and a controller ( ) which controls a degree of engagement of the modulating clutch ( ), characterized by including rotational frequency detectors ( ) which detect the rotational frequencies of right and left driving wheels ( ) of the vehicle, respectively, and characterized in that the controller ( ) controls the degree of engagement of the modulating clutch ( ) by detecting a sign of a wheel slip based on a difference in the rotational frequency between the right and left driving wheels ( ) detected by the rotational frequency detectors ( ), to prevent a slip.

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Komatsu, Japan

Nobumasa Takamatsu