Wheel loader and method for controlling a wheel loader
AssigneeKomatsu Ltd.
InventorAtsushi SHIRAO
Life of this patent
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Abstract
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.
Claims18
A wheel loader comprising:
- a working implement including a boom, a bucket and a lift cylinder that raises the bucket by moving the boom;
- an engine;
- a first hydraulic pump driven by the engine;
- a traveling hydraulic motor driven by hydraulic fluid discharged from the first hydraulic pump;
- a second hydraulic pump driven by the engine to discharge hydraulic fluid that drives the lift cylinder;
- a working implement operating member configured to operate the working implement;
- a drive circuit pressure detection part configured to detect a drive circuit pressure that is a pressure of the hydraulic fluid for driving the traveling hydraulic motor;
- a raising hydraulic stall determination part configured to determine whether or not the working implement is in a raising hydraulic stall condition, in which the bucket does not rise regardless of operation of the working implement operating member;
- a drive circuit pressure determination part configured to determine whether or not the drive circuit pressure is greater than or equal to a predetermined hydraulic pressure threshold;
- and
- a tractive force control part configured to perform a tractive force control to reduce a maximum tractive force, wherein
- the tractive force control part is further configured to reduce the maximum tractive force when determination conditions including, while the working implement is performing excavation operation, that the working implement is in the raising hydraulic stall condition and that the drive circuit pressure is greater than or equal to the predetermined hydraulic pressure threshold are satisfied during the tractive force control.
A method for controlling a wheel loader including an engine and a working implement including a boom, a bucket and a lift cylinder that raises the bucket by moving the boom, the method comprising:
- determining whether or not a raising hydraulic stall condition is occurring, in which the bucket does not rise even though hydraulic fluid discharged from a second hydraulic pump, which is driven by the engine, is supplied to the lift cylinder;
- determining whether or not a drive circuit pressure of a drive circuit, through which hydraulic fluid discharged from a first hydraulic pump driven by the engine is supplied to a traveling hydraulic motor, is greater than or equal to a predetermined hydraulic pressure threshold;
- and
- during a tractive force control for reducing a maximum tractive force is performed, further reducing a maximum tractive force when determination conditions including, while the working implement is performing excavation operation, that the raising hydraulic stall condition is occurring and that the drive circuit pressure is greater than or equal to the predetermined hydraulic pressure threshold are satisfied.
Dependencies are inferred from the claim text.