Servoactuator Limit Force Detection via Pressure Chamber
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Solution Overview
Problem
Conventional servo-controls in aircraft, particularly in helicopters, face challenges with high mechanical stresses during high-speed flight, leading to potential structural damage and requiring complex and costly limit force detection devices that can leak and induce play in the kinematic control chain.
Innovation Solution
A servo-control with a limit force detection device that includes a casing with a movable member dividing the detection space into two chambers, where the static force is detected by pressure changes within the internal space, eliminating the need for a dynamic seal and simplifying dimensioning, and optionally featuring a removable detection device and pressurization means to prevent hydraulic leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional limit force detection device is used in servo-controls, then limit forces can be detected, but the device becomes complex and prone to leakage
Solution Approach 1:
The patent extracts the detection function from the main servo-control body by using a separate detection chamber that communicates with the internal space through a communication orifice. This allows the limit force detection to be performed independently without requiring a complex integrated structure, thereby reducing overall device complexity while maintaining detection accuracy.
Solution Approach 2:
The patent introduces an intermediary detection chamber that mediates between the internal hydraulic space and the detection mechanism. This intermediary chamber allows pressure transmission without requiring direct mechanical connection, eliminating the need for dynamic seals and reducing the risk of leakage while simplifying the structure.
2Strength
If a dynamic seal is used in the limit force detection device, then the device can withstand mechanical stress, but hydraulic leakage occurs
Solution Approach 1:
The patent removes the dynamic seal component entirely by extracting the detection function into a separate chamber that communicates with the internal space through a fixed orifice. This eliminates the source of leakage while maintaining the ability to withstand mechanical stress through the rigid chamber structure.
Solution Approach 2:
The patent replaces the mechanical dynamic seal system with a hydraulic communication system using a fixed orifice. This substitution eliminates mechanical wear and leakage issues associated with dynamic seals while maintaining pressure transmission capability for stress resistance.
3Measurement precision
If the detection device is dimensioned to withstand high forces, then accuracy is improved, but the device becomes more complex and costly
Solution Approach 1:
The patent creates a simplified copy of the force detection function using a detection chamber that replicates the pressure conditions of the internal space. This allows accurate force detection through pressure measurement without requiring the detection device itself to be dimensioned for high forces, thereby reducing complexity and cost while maintaining precision.
4Reliability
If a complex limit force detection device is installed, then safety is improved, but maintenance costs increase
Solution Approach 1:
The patent extracts the detection function into a simple, separate chamber structure that can be easily monitored and maintained. The fixed orifice design eliminates complex sealing components that require frequent maintenance, thereby reducing maintenance costs while maintaining safety through accurate limit force detection.
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 effectively detects and alerts pilots to limit forces without external leaks or structural stress, reducing maintenance costs and mechanical stress on the aircraft, while maintaining precision and safety.
Implementation Method 1
The first detection chamber is supplied with fluid by the hydraulic circuit of the aircraft and the static force exerted on the servo-control varies linearly with the pressure of the fluid contained in this first detection chamber
Implementation Method 2
The second detection chamber is supplied with fluid by the same source as the internal space of the body, for example the hydraulic circuit, so that the pressure in this second chamber is constant
Data Source
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Figure 3~4
Figure 5
AI summary
A limit force detector device (20) detects a limit force. The detector device has a casing (21) secured to a structure (2) and defining a detection space. A movable element (50) is slidable in detection space, the movable element subdividing detection space into a right detection chamber (26) opening out to an inside space (10) and a left detection chamber (27). A detector unit (29) detects position of movable element in detection space to determine whether movable element has reached a predetermined limit position corresponding to presence of a limit force exerted on servo-control.