Shock Strut Damping Assembly With Selectable Orifice Profiles
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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 includes a main orifice assembly and a damping actor selector, allowing the shock strut assembly to transition between different damping configurations by altering the position of the metering pin and main orifice plate, thereby changing the damping curve through the deployment or retraction of flow restrictors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed damping configuration is used in the shock strut, then the structure is simple and reliable, but the damping characteristics cannot be adjusted for different aircraft activities
Solution Approach 1:
The patent implements dynamic adjustability by enabling the metering pin to rotate between multiple discrete positions (0°, 45°, 90°, 135°, 180°, 225°, 270°, 315°), each corresponding to a different damping configuration. This allows the shock strut to adapt its damping characteristics to various aircraft activities (landing, takeoff, taxiing, etc.) while maintaining a mechanically simple structure without continuous adjustment mechanisms.
Solution Approach 2:
The damping adjustment mechanism is segmented into discrete, pre-defined positions rather than continuous adjustment. The metering pin is divided into multiple circumferential positions, each providing a specific damping profile. This segmentation simplifies the control mechanism while providing versatile adaptability across different operating conditions.
2Reliability
If multiple damping configurations are provided for different aircraft activities, then the shock absorption performance is optimized, but the device complexity increases
Solution Approach 1:
The patent pre-configures multiple damping profiles by positioning the metering pin at specific discrete angles (0°, 45°, 90°, etc.), each optimized for particular aircraft activities. This preliminary configuration eliminates the need for complex real-time adjustment mechanisms, as the optimal damping profile is pre-established for each operating condition and selected by rotating the metering pin to the appropriate position.
Solution Approach 2:
The system changes damping parameters by rotating the metering pin to different circumferential positions, which alters the effective orifice area and flow characteristics. This parameter change mechanism provides multiple optimized damping configurations (different damping curves) without requiring complex additional components, simply by changing the angular position of the metering pin.
3Adaptability or versatility
If the metering pin is rotated to change damping profiles, then adaptability to different aircraft activities is improved, but the operation complexity increases
Solution Approach 1:
The metering pin rotation operates on a periodic basis, with each discrete position (0°, 45°, 90°, etc.) representing a stable, pre-defined damping configuration. The periodic nature of the rotation (360° cycle with 8 discrete positions) simplifies operation, as the user only needs to rotate the pin to the appropriate angle for the current aircraft activity rather than making continuous adjustments.
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 selection of pre-defined damping profiles tailored to specific aircraft activities, enhancing shock strut performance by optimizing damping characteristics for landing, takeoff, taxiing, and other operations, thereby improving ride quality and shock absorption.
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 main orifice plate assembly may be configured to transition a multi-actor damping system from a first damping actor configuration to a second damping actor configuration. The multi-actor damping system may be used in a shock strut assembly to alter a damping curve of the shuck strut assembly. The main orifice plate assembly may be a part of a main orifice assembly including an orbital cam. The main orifice plate may include a flow restrictor. The flow restrictor may be configured to retract or deploy in response to main orifice plate rotating about the orbital cam. 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.