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US 11,454,001 B2Granted
Excavator
AssigneeSumitomo Heavy Industries, Ltd.
InventorJunichi Okada
Life of this patent
Estimating the term…
Abstract
An excavator includes a hydraulic oil holding circuit that is provided in an oil passage between a bottom-side oil chamber of a boom cylinder and a control valve and is closed when the boom is not lowered, and a controller. The controller releases a closed state of the hydraulic oil holding circuit when the excavator is in a predetermined unstable state, and controls a released state so that an acting velocity in a lowering direction of the boom becomes less than or equal to a predetermined reference.
Claims16
An excavator comprising:
- an undercarriage;
- an slewing upper structure rotatably mounted on the undercarriage;
- attachments, mounted on the slewing upper structure, and including a boom, an arm, and an end attachment;
- a boom cylinder configured to drive the boom;
- a first hydraulic mechanism configured to control supply and discharge of a hydraulic oil to the boom cylinder according to an operation of the boom;
- a second hydraulic mechanism, provided in an oil passage between a bottom-side oil chamber of the boom cylinder and the first hydraulic mechanism, and configured to close when a lowering operation of the boom is not performed, and to open when the lowering operation of the boom is performed;
- and
- a processor configured to
- determine whether or not the excavator assumes a predetermined unstable action state when an overturning moment urging the excavator to overturn is transferred from one of the attachments to the slewing upper structure due to a change in a moment of inertia of the one of the attachments,
- release the second hydraulic mechanism from a closed state to an open state when the excavator is determined to, assume the predetermined unstable action state even while the lowering operation of the boom is not performed, and
- control the open state of the second hydraulic mechanism so that an acting velocity in a lowering direction of the boom is less than or equal to a predetermined reference,
- wherein the second hydraulic mechanism enables a flow of the hydraulic oil in the open state thereof, and disables the flow of the hydraulic oil in the closed state, thereof.
9 more elements
An excavator comprising:
- an undercarriage;
- an slewing upper structure rotatably mounted on the undercarriage;
- attachments, mounted on the slewing upper structure, and including a boom, an arm, and an end attachment;
- a boom cylinder configured to drive the boom;
- a first hydraulic mechanism configured to operate according to, an operation of the attachments;
- a second hydraulic mechanism, provided in an oil passage between a bottom-side oil chamber of the boom cylinder and the first hydraulic mechanism, and configured to close when a lowering operation of the boom is not performed;
- a detector configured to detect information related to a leak of a hydraulic oil in the oil passage on a downstream side opposite to the bottom-side oil chamber when viewed from the second hydraulic mechanism;
- and
- a processor configured to release the second hydraulic mechanism from a closed state to an open state when the excavator is in a predetermined unstable state, and control the open state so that, an acting velocity in a lowering direction of the boom is less than or equal to a predetermined reference,
- wherein the processor determines whether the leak of the hydraulic oil is generated in the oil passage on the downstream side of the second hydraulic mechanism, based on the information detected by the detector, when the second hydraulic mechanism is released from the closed state to the open state, and controls the open state of the second hydraulic mechanism so that the acting velocity becomes less than or equal to the predetermined reference, when the leak of the hydraulic oil is determined to be generated.
7 more elements
Dependencies are inferred from the claim text.