Metering Pin Damping Switching for Aircraft Shock Struts
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Solution Overview
Problem
Current shock strut systems in aircraft landing gear lack the ability to dynamically adjust damping characteristics in response to varying aircraft activities, such as landing, takeoff, and taxiing, which can lead to suboptimal shock absorption and ride quality.
Innovation Solution
A multi-actor damping system that incorporates a metering pin and main orifice plate, allowing for the transition between different damping configurations by altering the position of the metering pin and orifice plate, thereby changing the damping curve in response to specific aircraft activities through a damping actor selector mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional shock strut system with fixed damping characteristics is used, then the structure is simple and reliable, but the shock absorption performance is suboptimal under varying aircraft activities
Solution Approach 1:
The patent implements a metering pin with multiple flute profiles at different radial positions that can be selectively engaged by a damping actor selector. This allows the damping characteristics to be dynamically changed by rotating the selector to engage different flute profiles, transforming a static damping system into a dynamic one that adapts to varying aircraft activities such as landing, takeoff, and taxiing.
Solution Approach 2:
The metering pin is segmented into multiple functional zones with different flute profiles (first flute profile, second flute profile, third flute profile) positioned at different radial distances from the center. Each flute profile corresponds to a specific damping characteristic. The damping actor selector segments the control mechanism into discrete positions that engage specific flute profiles, allowing selective activation of different damping modes.
2Adaptability or versatility
If multiple damping configurations are implemented to handle different aircraft activities, then the adaptability improves, but the device complexity increases
Solution Approach 1:
The metering pin serves multiple functions simultaneously: it acts as a flow restrictor, a selector mechanism, and a damping characteristic provider. The single metering pin component integrates multiple flute profiles that can be selectively engaged, eliminating the need for separate damping devices for different aircraft activities. The damping actor selector rotates to engage different flute profiles, providing universal control over multiple damping configurations.
Solution Approach 2:
The patent merges the metering pin function with the damping configuration selection function. Instead of having separate components for metering and damping selection, the metering pin itself contains multiple flute profiles that are selectively engaged by rotation. This combines what would traditionally be separate components into a single integrated solution, reducing overall system complexity while maintaining multiple damping configurations.
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 enhanced shock strut performance by allowing selection of pre-defined damping profiles tailored to specific aircraft activities, improving shock absorption and ride quality across different operational conditions.
Implementation Method 1
a trapped volume of gas is compressed as the shock strut is axially compressed, and a volume of oil is metered through an orifice. The gas acts as an energy storage device, similar to a spring, so that upon termination of a compressing force the shock strut returns to its original length.
Implementation Method 2
Shock struts also dissipate energy by passing the oil through the orifice so that as the shock absorber is compressed or extended, its rate of motion is limited by the damping action from the interaction of the orifice and the oil.
Data Source
AI summary
A metering pin for use in a multi-actor damping system is disclosed herein. The multi-actor damping system may be used in a shock strut assembly to alter a damping curve of the shuck strut assembly. The metering pin may be configured to transition the multi-actor damping system from a first damping actor configuration to a second damping actor configuration. The first damping actor configuration may correspond to a first damping curve. The second damping actor configuration may correspond to a second damping curve. The first damping curve being different than the second damping curve.