Load-Sensing Hydraulic Pump Switching for Steering and Loading Performance
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Solution Overview
Problem
Hydraulic systems with load-sensing fixed/variable-displacement face performance and efficiency issues in certain applications, necessitating a balance between energy conservation and performance that existing technologies fail to achieve effectively.
Innovation Solution
A hydraulic system switchable between fixed-displacement and fixed/variable-displacement modes, incorporating a displacement changing mechanism, load-sensing system, and a control method that allows operators to switch between modes based on differential pressure thresholds, using a fixed/variable-displacement switching control valve and pressure cut-off control valve to manage pump displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a load-sensing fixed/variable-displacement hydraulic system is used to achieve energy conservation, then energy efficiency is improved, but steering performance and loading efficiency deteriorate
Solution Approach 1:
The system dynamically switches between variable-displacement and fixed-displacement modes based on operational conditions. The working pump is equipped with a displacement changing mechanism that can adjust displacement based on load-sensing signals, while a switching control valve enables transition between variable and fixed displacement states, optimizing both energy efficiency and steering performance for different working conditions
Solution Approach 2:
The system changes the displacement parameter of the working pump based on operating conditions. By adjusting the displacement of the variable piston pump through the displacement changing mechanism and switching control valve, the system adapts between energy-saving variable displacement mode and high-performance fixed displacement mode, resolving the contradiction between energy efficiency and steering performance
2Use of energy by moving object
If a load-sensing fixed/variable-displacement hydraulic system is used to achieve energy conservation, then energy efficiency is improved, but loading efficiency deteriorates
Solution Approach 1:
The system dynamically adjusts the displacement mode of the working pump based on loading conditions. The switching control valve responds to differential pressure signals to transition between variable-displacement and fixed-displacement modes, ensuring high loading efficiency during heavy operations while maintaining energy efficiency during lighter tasks
Solution Approach 2:
The displacement parameter of the working pump is changed based on loading requirements. The load-sensing system detects pressure differential across the switching control valve, triggering displacement mode changes that optimize loading efficiency when needed and energy consumption when loads are lighter
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
Enables a better balance between energy conservation and performance by allowing the hydraulic system to adapt its displacement mode according to operational demands, improving steering performance and loading efficiency.
Implementation Method 1
when a differential pressure between input pressure of the first control port and input pressure of the second control port is greater than a first threshold
Implementation Method 2
a working pump, including a displacement changing mechanism for changing a displacement of the working pump, wherein an oil inlet of the working pump is in fluid communication with the oil supply port of the oil tank
Data Source
AI summary
Disclosed are a hydraulic system, a control method and a working machine. The hydraulic system includes an oil tank, a working pump, a control cylinder controlling a displacement changing mechanism, a working oil line communicating with an output main path of the working pump, a load-sensing system including a load-sensing circuit outputting hydraulic pressure based on load, a load-sensing valve and a switching-control valve switchable between a first-valve-position and a second-valve-position. When differential pressure between the first and second control ports is greater than a first threshold, the output main path communicates with an input port of the control cylinder; when it is less than the first threshold, the input port communicates with an oil return port of the oil tank. Based on this, operators can switch the hydraulic system between the fixed-displacement mode and the fixed/variable-displacement mode, thereby achieving a better balance between energy conservation and performance.