Aircraft Engine Air Bleed Flap Preload Adjustment for Torque Consistency
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Solution Overview
Problem
Existing air bleed scoop adjustment devices in aircraft engines face challenges in precise control due to variability in spring calibration and manufacturing differences, leading to inconsistent return torques and calibration across a series of valves.
Innovation Solution
A torsion spring return system where the second end is connected to the frame via adjustable means, such as a screwing mechanism, allowing independent adjustment of the return torque and compensating for manufacturing variations, using a connecting rod with a ball joint and guide ring for precise guidance and a self-locking nut for secure adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the spring is fixed directly to the frame and shaft, then the structure is simple, but the return torque cannot be adjusted independently and manufacturing variations cause inconsistent performance
Solution Approach 1:
A connecting rod with ball joint and guide ring is introduced as an intermediary between the spring and the frame. This intermediary mechanism allows the spring's second end to move freely in the guide ring while being guided by the connecting rod, enabling independent adjustment of the spring preload through the adjusting screw without affecting the flap position, thus achieving consistent return torque across manufacturing variations
Solution Approach 2:
The connection point of the spring's second end is made dynamic through the guide ring and connecting rod mechanism. Instead of being fixed to the frame, the spring's attachment point can move along the guide ring's path, allowing the preload to be adjusted independently while maintaining proper spring orientation and function during operation
2Manufacturing precision
If the stop position is adjusted to compensate for spring variations, then the return torque consistency improves, but the flap extreme positions become imprecise
Solution Approach 1:
The adjustment function is segmented into two independent parts: (1) the stop piece that controls the flap's extreme positions by contacting the frame, and (2) the adjusting screw mechanism that controls the spring preload independently. This segmentation allows each function to be optimized separately - the stop piece ensures precise flap positioning while the adjusting screw ensures consistent return torque, without interfering with each other
3Manufacturing precision
If a series of valves are manufactured with identical spring settings, then consistency improves, but manufacturing variations in spring production make this difficult
Solution Approach 1:
The adjusting screw mechanism enables each valve to be self-adjusted during final assembly or maintenance. Instead of requiring precise spring manufacturing tolerances, each spring can be individually adjusted using the screw mechanism to achieve the correct preload, making the system tolerant of spring manufacturing variations while ensuring consistent performance across all valves in the series
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 precise and consistent calibration of the spring return torque, overcoming manufacturing variability and simplifying the adjustment process, ensuring identical performance across a series of valves without complex maneuvers.
Implementation Method 1
a return system configured to stress the flap in a determined position around the axis and comprising a torsion spring, one end of which is connected to the flap and the other end of which is connected to the frame
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to an air bleed device for an aircraft engine, comprising a supporting structure (12) and a flap able to rotate about an axis (X) in relation to the supporting structure (12), said device further comprising a return system, designed to bias the flap in a defined position about the axis (X) and having a torsion spring (13), a first end (15) of which is connected to the flap and a second end (16) of which is connected to the supporting structure (12), characterized in that said second end (16) is connected to the supporting structure by way of means (17) for the screwed adjustment of the spring preload when the flap is in the defined position.