Excavator Boom Hydraulic Valve Layout to Prevent Cylinder Cavitation
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Solution Overview
Problem
The existing hydraulic control systems in excavators face issues with low hydraulic oil flow rates to the rod chamber, leading to cavitation or detonation during boom descent, which significantly damages the system and reduces its service life.
Innovation Solution
A hydraulic control system with parallel forward and reverse proportional valves, integrated or independently disposed, ensures timely and sufficient hydraulic oil supply to the rod chamber through multiple oil paths, including a first oil path to the rodless chamber, a second oil path to the oil tank, and a third oil path to the rod chamber, utilizing a back pressure and floating oil paths to enhance flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a main valve is used to control hydraulic oil flow from the rodless chamber to the rod chamber, then the system structure is simple, but the flow rate of hydraulic oil supplied to the rod chamber is relatively low
Solution Approach 1:
The patent divides the single main valve into multiple proportional valves (first proportional valve, second proportional valve, third proportional valve) with separate oil paths. Each valve handles a portion of the hydraulic oil flow, allowing parallel flow paths that increase the total flow rate to the rod chamber while maintaining manageable system complexity through modular valve design.
2Stability of the object's composition
If the hydraulic oil flow rate to the rod chamber is low, then the system operates smoothly, but cavitation or detonation occurs in the boom cylinder during rapid descent
Solution Approach 1:
The patent changes the flow rate parameter by introducing multiple proportional valves with adjustable opening degrees. The controller dynamically adjusts the opening degrees of the first, second, and third proportional valves to increase the hydraulic oil flow rate to the rod chamber during rapid descent, preventing cavitation and detonation while maintaining system stability through controlled parameter adjustment.
3Reliability
If multiple proportional valves are added to increase hydraulic oil flow rate, then cavitation is prevented, but the device complexity increases
Solution Approach 1:
The patent combines multiple proportional valves (first, second, and third proportional valves) with their respective oil paths into an integrated valve assembly. This merging approach increases the hydraulic oil flow rate capability to prevent cavitation while managing the complexity through a unified structural design that coordinates all valves and paths systematically.
Solution Approach 2:
The proportional valves serve multiple functions: the first proportional valve controls flow from the rodless chamber to the rod chamber, the second proportional valve provides alternative flow paths, and the third proportional valve regulates return flow. This multi-functionality allows the system to achieve high flow rates and prevent cavitation while keeping the valve system design efficient and coordinated.
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
Prevents cavitation and detonation in the boom cylinder, prolongs the hydraulic control system's service life, improves operational efficiency, and reduces energy consumption by optimizing oil flow management.
Implementation Method 1
a first oil path communicating with a rodless chamber of a boom cylinder; a second oil path communicating with an oil tank; a third oil path communicating with a rod chamber of the boom cylinder
Data Source
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AI summary
The present invention provides a hydraulic control system and method, and an excavator. The hydraulic control system includes: a first oil path, a second oil path, a third oil path and a plurality of proportional valves. The first oil path communicates with a rodless chamber of a boom cylinder. The second oil path communicates with an oil tank. The third oil path communicates with a rod chamber of the boom cylinder. The proportional valve includes an oil inlet communicating with the first oil path, an oil return port communicating with the second oil path, and an oil outlet communicating with the third oil path. The proportional valves include a forward proportional valve and a reverse proportional valve arranged in parallel, the oil return port of the forward proportional valve maintains communicating with the oil inlet of the forward proportional valve, and the oil return port of the reverse proportional valve maintains communicating with the oil outlet of the reverse proportional valve.