Excavator Hydraulic Flow Control for Swing-Stick Interlocking
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Solution Overview
Problem
In hydraulic excavators, the swiveling motor and working machine hydraulic actuators share a hydraulic pump, leading to reduced swiveling power due to insufficient flow rate when operated interlockingly, as existing technologies fail to effectively control the opening area of the swivel preferred flow control valve, affecting the relationship between supply and discharge flow rates.
Innovation Solution
A hydraulic control system with a swiveling motor, hydraulic pump, direction change-over valves, and flow control valves, where a control means sets target supply flow rates and differential pressures to adjust the opening area of the flow control valve based on operating conditions, ensuring adequate pressure and flow during interlocking operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single spool valve is used to simultaneously perform direction change-over control, supply flow control, and discharge flow control, then the device complexity is reduced, but the ability to independently control supply and discharge flow rates is lost
Solution Approach 1:
The patent divides the hydraulic control system into separate functional components: a direction change-over valve for controlling oil flow direction and a flow control valve for independently regulating supply and discharge flow rates. This segmentation allows each component to specialize in its function, enabling flexible adaptation to different operating conditions while maintaining reasonable system complexity.
2Power
If the flow control valve is used to control the supply flow rate during interlocking operation, then the swiveling power is improved, but the working machine's hydraulic actuator receives insufficient flow rate
Solution Approach 1:
The control means monitors the operating states of both the swiveling manipulator and working machine manipulator, and dynamically adjusts the flow control valve's opening area based on this feedback. During interlocking operation, the system calculates appropriate flow distribution to ensure the swiveling motor receives sufficient flow for required swiveling power while maintaining adequate flow to the working machine's hydraulic actuator for continued operation.
3Measurement precision
If the target differential pressure is increased during interlocking operation, then the flow rate control precision is improved, but the pressure loss in the hydraulic system increases
Solution Approach 1:
The patent implements dynamic adjustment of the target differential pressure based on real-time operating conditions. The control means modifies the target differential pressure setting according to the interlocking operation state, manipulating arm position, and load conditions, optimizing the balance between flow rate control precision and hydraulic system efficiency without excessive pressure loss.
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 allows for precise control of the flow control valve opening area, enhancing the accuracy of supply flow rate management and simplifying interlocking operation tuning, thereby maintaining swiveling power and improving operational efficiency.
Implementation Method 1
a flow control valve arranged at the upstream side of the working machine's direction change-over valve for controlling the supply flow rate from the hydraulic pump to the working machine's direction change-over valve
Implementation Method 2
a swiveling's direction change-over valve having supply/discharge valve passages for the swiveling motor and changing over its supply/discharge directions
Data Source
AI summary
Problem to Be Solved: To investigate an opening area control of a flow control valve disposed on upstream side of the stick's direction change-over valve when using the flow control valve as a valve for restricting the supply flow rate to stick cylinder during interlocking operation of the swiveling motor and stick cylinder. Solution: A configuration is provided to control the opening area of the stick's first flow control valve based on a target supply flow rate to the stick cylinder, target differential pressure between first hydraulic pump A and supply pressure to the stick cylinder, and opening area of supply valve passage to the stick's direction change-over valve and also control that the differential pressure is set larger as operating amount of swiveling manipulator increases during interlocking operation of the swiveling motor and stick cylinder and the opening area of stick's first flow control valve is made smaller as the differential pressure increases.