Segmented Spring Guide Assembly for Valve Resonance Control

Solution Overview

Problem

Pneumatic passive bleed valves in aircraft engines experience high cycle fatigue and wear failures due to axial resonance caused by compressed springs enduring high levels of vibration in low damping mediums like air.

Innovation Solution

A segmented spring guide assembly comprising two coil springs and their respective guides, connected by a cylindrical connector, which maintains sliding contact and doubles the natural frequency of the springs, shifting the resonance away from critical driving frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a compressed spring is used in a pneumatic passive bleed valve, then the valve can maintain the piston in place and provide biasing force, but the spring undergoes high cycle fatigue and wear failures due to axial resonance in high vibration environments

Engineering Contradiction:

Improvespring lifeVSAvoidaxial resonance and high cycle fatigue

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The spring guide assembly is divided into multiple segments (first spring guide assembly, second spring guide assembly, etc.) connected in series along the piston stroke axis. Each segment contains its own spring and spring guide, with movable connections between segments that allow relative motion. This segmentation distributes the vibration and resonance effects across multiple independent units, preventing the axial resonance that causes high cycle fatigue in a single continuous spring.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If a single spring guide assembly is used, then the structure is simple, but the natural frequency of the spring matches critical driving frequencies causing resonance

Engineering Contradiction:

Improvespring guide assembly structureVSAvoidresonance avoidance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The spring guide assembly is divided into multiple segments (first spring guide assembly, second spring guide assembly, etc.) connected in series along the piston stroke axis. Each segment contains its own spring and spring guide, with movable connections between segments that allow relative motion. This segmentation distributes the vibration and resonance effects across multiple independent units, preventing the axial resonance that causes high cycle fatigue in a single continuous spring.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The segments of the spring guide assembly are movably connected, allowing dynamic adjustment and relative motion between segments during piston operation. This dynamic configuration enables the system to adapt to varying operating conditions and shift natural frequencies away from critical driving frequencies, reducing resonance effects while maintaining structural integrity.

Inventive Principle:

Principle #15Dynamics

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

This configuration reduces the risk of failure from high cycle fatigue and wear, extending the average spring life while maintaining equivalent spring rate and sliding engagement throughout the piston stroke.

Implementation Method 1

doubles the natural frequency of the springs, shifting the resonance away from critical driving frequencies

Methodology Applied

Scientific EffectNatural frequency: Harmonic Oscillator

Implementation Method 2

A resulting axial resonance may cause high cycle fatigue and wear failures

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 3

the connector has a length that enables the first spring guide and the second spring guide to maintain sliding contact while the piston moves along the piston stroke axis

Methodology Applied

Scientific EffectSliding contact: Friction

Data Source

PatentEP3546807B1Valve with segmented spring guide assembly

Publication Date: 2022.08.03 HAMILTON SUNDSTRAND CORP

Figure 1~2

AI summary

Disclosed is a method of applying a biasing force against a piston (142) in a valve (140) as the piston moves along a piston stroke axis in a first direction and an opposing second direction, the piston having a first axial end that is a distal end of the piston, the method including: moving the piston along a piston stroke axis in the first direction and the opposing second direction, wherein while moving the piston along the piston stroke axis: applying a first biasing force in the second direction against the first axial end of the piston from a first spring, and applying a second biasing force in the second direction against the first spring from a second spring.