Boom Drive Device Power Reduction via Reaction Force
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Solution Overview
Problem
Conventional hydraulic excavators require significant power for operations like boom raising and arm crowding, and existing solutions do not effectively reduce the required horsepower, especially during combined operations.
Innovation Solution
A boom driving apparatus with a variable-displacement hydraulic pump, boom control valve, boom-raising-operation detector, boom-cylinder pressure detector, supply selector valve, and controller that allows the hydraulic pump to reduce power by blocking oil supply when the excavation reaction force naturally extends the boom cylinder, thereby reducing the power needed for operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic oil is continuously supplied to extend the boom cylinder during combined operations, then the boom raising operation is ensured, but the power consumption of the hydraulic pump increases significantly
Solution Approach 1:
The system allows the boom cylinder to extend automatically using the excavation reaction force generated during arm crowding operation, without requiring active hydraulic oil supply from the pump. The hydraulic circuit is configured so that when the arm cylinder extends (crowding operation), the reaction force naturally extends the boom cylinder, making the system self-sufficient for boom raising during combined operations
Solution Approach 2:
The invention converts the excavation reaction force, which was previously considered a harmful factor causing vehicle body raising, into a beneficial force that automatically extends the boom cylinder. By utilizing this reaction force through the configured hydraulic circuit, the system achieves power reduction while maintaining operational reliability
2Use of energy by moving object
If the hydraulic pump reduces power by blocking oil supply, then power consumption is reduced, but the boom cylinder extension may be insufficient
Solution Approach 1:
The hydraulic pump operates in two dynamic modes: high-power mode for general operations and low-power mode for combined operations where excavation reaction force is sufficient. The system dynamically switches between these modes based on operational conditions, optimizing both power consumption and productivity
3Ease of operation
If a selector valve is used to permit oil flow only when boom cylinder reaches given height, then automatic extension is achieved, but power reduction is hardly effective
Solution Approach 1:
The invention merges the control functions of the boom cylinder and arm cylinder into a unified hydraulic circuit configuration. By connecting the head-side chamber of the boom cylinder and head-side chamber of the arm cylinder through a common hydraulic passage, the system achieves coordinated automatic extension of both cylinders during combined operations, enhancing both ease of operation and power reduction effectiveness
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively reduces the power required for hydraulic excavator operations by utilizing the excavation reaction force to extend the boom cylinder without active hydraulic oil supply, ensuring normal operation while minimizing the hydraulic pump's power consumption.
Implementation Method 1
a variable-displacement hydraulic pump (10) which sucks hydraulic oil stored in a tank and discharges the hydraulic oil
Implementation Method 2
the excavation reaction force which a working attachment receives from the ground during excavating work acts as a force which extends a boom cylinder
Implementation Method 3
the gravity acting on the base machine and the like serves to keep the base machine in contact with the ground against the excavation reaction force
Data Source
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AI summary
Provided is an apparatus for driving a boom of a construction machine, allowing required power to be reduced. The construction machine includes a boom cylinder 6, a variable-displacement hydraulic pump 10, a control valve 12 guiding hydraulic oil discharged by the variable-displacement hydraulic pump 10 to the boom cylinder 6, a boom-raising-operation detector 42 which detects a boom raising operation, boom-cylinder pressure detectors 46A and 46B, a supply selector valve 30 switchable between a permitting position for permitting the hydraulic oil to be supplied from the hydraulic pump 10 to a head-side chamber 6a of the boom cylinder 6 and a blocking position for blocking the supply, a supply oil passage 34 permitting hydraulic oil to be supplied to the head-side chamber 6a during the blocking, and a controller 50 which brings the supply selector valve 30 into the blocking position and reduces volume of the hydraulic pump 10 upon judging that excavation reaction force extends the boom cylinder 6 even with no supply of hydraulic oil from the hydraulic pump 10 to the head-side chamber 6a.