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AssigneeDoosan Infracore Co., Ltd.
InventorsHyeong Kim, Won Sohn
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A hydraulic control device of an excavator is provided for controlling combined operation of boom-raising and swing on a slope. A swing priority valve (20) is provided on a pressured fluid supply line (8) that connects a first hydraulic pump (1) to a boom high-speed control valve (7). If an excavator performs its tasks on a slope, the swing priority valve (20) is automatically shifted under a control of an electronic controller (28) into a throttling position to thereby restrict hydraulic flow through the boom high-speed control valve (7) so that an increased amount of hydraulic flow can be supplied to a swing motor (14), thus increasing a swing operating pressure more rapidly than a boom operating pressure and consequently facilitating combined operation of boom-raising and swing on a slope.
A hydraulic control device of an excavator comprising a first hydraulic pump (1), a second hydraulic pump (2), a swing control valve (6) in fluid communication with the first hydraulic pump (1) for controlling hydraulic flow from the first hydraulic pump (1) to a swing motor (14), a boom high-speed control valve (7) disposed at downstream of the swing control valve (6) and in fluid communication with the first hydraulic pump (1) via a pressured fluid supply line (8) for controlling hydraulic flow from the first hydraulic pump (1) to boom cylinders (15), and a boom low-speed control valve (11) for controlling hydraulic flow from the second hydraulic pump (2) to the boom cylinders (15), further comprising:
Dependencies are inferred from the claim text.