Electro-hydraulic Actuator Flow Control and Cavitation Prevention
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Solution Overview
Problem
Conventional electro-hydraulic actuators face issues with uncontrolled movement of loads due to external forces, leading to 'run-away' situations or system pressure drops, especially when loads are actuated against gravity, and suffer from cavitation problems at extreme temperatures due to inefficient fluid filtration.
Innovation Solution
Incorporation of pressure compensated flow control valves to regulate flow rates and maintain internal pressure, along with a filter placement on fluid return to the reservoir to ensure pressurized filtration, and integration of combination manual release and thermal expansion valves within the manifold for enhanced control and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If pressure compensated flow control valves are used to limit maximum flow rate, then actuator movement is controlled and stable, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into single components: the flow control valves are integrated with the manifold, and combination manual release/thermal expansion valves are used. This merging reduces the number of separate components while maintaining the required flow control and stability functions.
Solution Approach 2:
The combination manual release and thermal expansion valves perform multiple functions simultaneously - manual release for emergency operation and thermal expansion for pressure regulation. This multi-functionality addresses multiple system requirements with a single component, managing complexity.
2Reliability
If filter is placed on fluid return to reservoir for pressurized filtration, then cavitation is avoided, but device complexity increases
Solution Approach 1:
The filter is positioned in the fluid return line before fluid enters the reservoir, performing filtration while the fluid is still under pressure. This preliminary filtration action prevents cavitation by removing contaminants that could cause it, while utilizing the existing system pressure rather than requiring additional pressure generation equipment.
3Reliability
If combination manual release and thermal expansion valves are integrated in manifold, then system robustness is enhanced, but manufacturing complexity increases
Solution Approach 1:
Multiple valve functions (manual release and thermal expansion) are integrated into the manifold structure itself, eliminating the need for separate valve housings and reducing the number of assembly steps. This merging approach enhances system robustness while simplifying manufacturing compared to using separate components.
4Stability of the object's composition
If pressure compensated flow control valves are used to maintain internal pressure, then run-away situations are prevented, but device complexity increases
Solution Approach 1:
The pressure compensated flow control valves automatically regulate flow based on system pressure conditions without requiring external control systems. The valves self-adjust to maintain stable internal pressure and prevent run-away situations, achieving pressure stability through inherent valve characteristics rather than complex external control mechanisms.
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
The solution ensures controlled and stable actuator movement, prevents 'run-away' situations, maintains system pressure, and avoids cavitation, resulting in a more robust, compact, and self-contained hydraulic system with reduced weight and size.
Implementation Method 1
a plurality of pressure compensated flow control valves for limiting the maximum flow rate through the fluid conduits regardless of the loads imparted on the actuator
Implementation Method 2
a filter for filtering fluid as the fluid returns to the reservoir from the actuator
Implementation Method 3
a plurality of combination manual release, thermal expansion valves received in the manifold
Data Source
AI summary
An electro-hydraulic actuator (EHA) includes a hydraulic circuit having a plurality of pressure compensated flow control valves for limiting the maximum flow rate through the fluid conduits regardless of the loads imparted on the actuator. In one embodiment of the EHA, a plurality of combination manual override/thermal expansion valves that simplify the manufacture of the EHA.