Excavator Hydraulic Flow Sharing for Boom Raise and Swing
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Solution Overview
Problem
Existing hydraulic drive systems for working machines, such as hydraulic excavators, experience energy wastage when both boom raising and swing operations are performed simultaneously due to independent supply lines for the swing motor and boom cylinder, leading to unnecessary activation of the swing relief valve and hydraulic oil discard.
Innovation Solution
A hydraulic drive system with a controller that manages the flow of hydraulic oil between the first and second pumps, using a third control valve to divert oil from the swing motor to the boom cylinder when the swing motor load pressure is higher, and shutting off this diversion when the swing motor reaches a steady state, thereby optimizing energy usage by connecting and disconnecting the supply lines based on load pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If independent supply lines are used for swing motor and boom cylinder, then energy loss from throttling is reduced, but swing relief valve activates unnecessarily causing hydraulic oil discard
Solution Approach 1:
A third control valve is introduced as an intermediary component between the second hydraulic pump and both the swing motor and boom cylinder. This valve acts as a mediator that dynamically routes hydraulic oil based on operational conditions, preventing unnecessary activation of the swing relief valve while maintaining independent control capability when needed.
Solution Approach 2:
The system transitions from static independent supply lines to a dynamic configuration where the third control valve adjusts hydraulic oil distribution in real-time based on load pressure conditions. The controller dynamically opens or closes the third control valve to optimize energy usage and prevent hydraulic oil discard during simultaneous swing and boom raising operations.
2Use of energy by moving object
If third control valve is opened to supply hydraulic oil to boom cylinder from second pump, then energy usage is optimized, but control complexity increases
Solution Approach 1:
The controller receives feedback regarding load pressure conditions and operational state (whether swing motor is in steady state) to automatically adjust the third control valve. This feedback mechanism enables the system to optimize energy usage by opening the third control valve when beneficial, while automatically returning to independent supply mode when swing operation requires full power, thus managing control complexity through automated decision-making.
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 efficiently uses energy during simultaneous boom raising and swing operations by minimizing wasteful energy consumption and optimizing hydraulic oil distribution, reducing unnecessary pressure relief and maintaining independent operation when required.
Implementation Method 1
an on-off solenoid valve which is disposed between the boom operating device and the third control valve and opens and closes based on a command current from the controller
Data Source
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AI summary
In a specific state where the raising operation of a boom 25 and the swing operation of an upperstructure 21 are performed at the same time to supply a hydraulic oil from a first pump 2 to a cylinder 7a through a first valve 6a, and to supply the same from a second pump 3 to a motor 7b through a second valve 6b, a controller 10 outputs the command current for opening a valve 13, and supplies a part of the hydraulic oil supplied to the motor 7b from the second pump 3 to the cylinder 7a through the third valve 6c when the motor 7b does not reach a steady swing state, and outputs a command current for closing the valve 13 when the motor 7b is in the steady swing state.