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US 8,639,429 B2Granted
Wheel loader and method for controlling a wheel loader
AssigneeKomatsu Ltd.
InventorAtsushi Shirao
Life of this patent
Estimating the term…
Abstract
A tractive force control part of a wheel loader reduces the maximum tractive force when determination conditions are satisfied during tractive force control. The determination conditions include that the work phase is excavation, that the working implement is in the raising hydraulic stall condition and that drive circuit pressure is greater than or equal to a predetermined pressure threshold.
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 tractive force operating member configured to switch tractive force control for reducing maximum tractive force between an ON condition and an OFF condition;
- 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 work phase determination part configured to determine whether or not a work phase is excavation;
- 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 reduce the maximum tractive force when the tractive force control is in the ON condition to be below the maximum tractive force when the tractive force control is in the OFF condition, wherein
- the tractive force control part is further configured to reduce the maximum tractive force when determination conditions including that the work phase is excavation, 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.
11 more elements
A method for controlling a wheel loader, the 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 tractive force operating member configured to switch tractive force control for reducing maximum tractive force, between an ON condition and an OFF condition,
- a drive circuit pressure detection part configured to detect a drive circuit pressure that is a pressure of the hydraulic fluid that drives the traveling hydraulic motor, the method comprising:
- determining whether or not a work phase is excavation;
- determining 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;
- determining whether or not the drive circuit pressure is greater than or equal to a predetermined hydraulic pressure threshold;
- reducing the maximum tractive force when the tractive force control is in the ON condition to be below the maximum tractive force when the tractive force control is in the OFF condition;
- and
- further reducing the maximum tractive force when determination conditions including that the work phase is excavation, 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.
11 more elements
Dependencies are inferred from the claim text.