Fluid Actuator Limit Valves for Hydraulic Leakage Correction
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Solution Overview
Problem
Hydraulic circuits have not been able to fully replace mechanical linkages in precision applications due to the inability to detect and correct hydraulic fluid leakage, requiring continuous monitoring and adjustable mechanical stops to prevent over extension or retraction, which complicates the design and reliability of hydraulic linkages.
Innovation Solution
Integration of adjustable mechanical stops or cushions into hydraulic actuators with limit sensors that activate fluid valves to redirect fluid and prevent over extension or retraction, allowing for intermittent detection and correction of hydraulic leakage without continuous monitoring or an electronic control system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical linkages are replaced with hydraulic linkages, then ease of routing and mode switching is improved, but the ability to detect and correct fluid leakage deteriorates
Solution Approach 1:
The patent implements feedback mechanisms through limit sensors that detect piston position and fluid limit valves that monitor fluid pressure. When leakage occurs, the system detects the position discrepancy between the actuator piston and the floating piston, and automatically corrects it by redirecting fluid through the bypass valve, creating a closed-loop feedback system that maintains reliability.
Solution Approach 2:
The hydraulic linkage system performs self-diagnosis and self-correction of leakage without requiring external electronic control systems. The limit sensors and fluid limit valves work autonomously to detect fluid loss and redirect fluid through the bypass valve, allowing the system to service itself and maintain operational reliability.
2Reliability
If continuous monitoring and electronic control systems are used to detect and correct leakage, then leakage detection capability is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex electronic control systems with a purely mechanical detection and correction system. Limit sensors mechanically detect piston position, and fluid limit valves mechanically redirect fluid based on pressure differential, eliminating the need for electronic sensors, processors, and actuators while maintaining effective leakage detection and correction.
Solution Approach 2:
The system autonomously detects and corrects leakage without requiring external electronic control. The mechanical components self-regulate fluid flow based on their physical state, providing a simple, reliable solution that avoids the complexity of electronic monitoring systems.
3Reliability
If adjustable mechanical stops are used to prevent over extension, then reliability is improved, but device complexity and adjustability deteriorate
Solution Approach 1:
The patent replaces fixed mechanical stops with a dynamic, adjustable limit system. The floating piston can be repositioned along the cylinder to change the limit position, and the system automatically adapts to different operating conditions through the mechanical interaction between the actuator piston and floating piston, providing both reliability and adjustability.
Solution Approach 2:
The limit sensor and fluid limit valve mechanism serves multiple functions: it prevents over-extension, allows adjustable limit positioning, and corrects fluid leakage. This multi-functional design eliminates the need for separate adjustment mechanisms, reducing overall device complexity while maintaining reliability and adaptability.
4Device complexity
If limit sensors and fluid limit valves are integrated into the actuator, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent combines the limit sensing function and fluid limit valve function into a single integrated mechanism within the actuator. The limit sensor and floating piston work together as one system, eliminating the need for separate components and reducing manufacturing precision requirements compared to integrating multiple independent systems.
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 the use of hydraulic linkages in precision applications like vehicle steering by simplifying the design, improving reliability, and allowing for accurate control of piston movement, reducing the need for continuous hydraulic source availability and electronic monitoring.
Implementation Method 1
fluid limit valves that redirect fluid to bypass the fluid actuator's piston
Implementation Method 2
limit sensors that activate fluid valves to redirect fluid and prevent over extension or retraction
Implementation Method 3
The extension of the actuator piston is mechanically limited by the floating piston
Data Source
AI summary
A fluid actuator with fluid limit valves (550, 551) and adjustable mechanical limits enables the construction of fluid linkages which are able to completely replace mechanical linkages. In a fluid circuit comprising of two or more fluid actuators, the pistons (102) of the fluid actuators can become uncorrelated when fluid leakage occurs. At the piston (102) extension and retraction limits, fluid limit valves (550, 551) open. The open fluid limit valves (550, 551) allow fluid to bypass pistons (102) and/or allow fluid from an external source to compensate the fluid leakage. The fluid bypassing pistons (102) at their extension or retraction limit and/or externally supplied fluid forces the uncorrelated pistons (102) to reach their extension or retraction limit as well. The fluid actuator with adjustable mechanical limits have one or more additional pistons (686, 688), which have an adjustable separation from the main piston (102) or end of cylinder. The fluid actuator with fluid limit valves (550, 551) and adjustable mechanical limits enables mechanical linkages to be replaced by fluid circuits composed of the fluid actuators.