Burst Device Support Sleeve Reduces Inflator Bursting Pressure

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Solution Overview

Problem

Existing hybrid inflators require extremely high bursting pressures to open the burst cap, leading to excessive stress and deformation, necessitating thick, costly materials to withstand high filling pressures, which can cause detrimental effects on other components.

Innovation Solution

A burst device with a support sleeve that reduces the bursting pressure required to open the burst member, allowing it to have a thinner design and be supported by the sleeve rather than the igniter, thereby minimizing material thickness and costs while maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the burst cap is designed to withstand high filling pressures (up to 800 bar), then the structural integrity and reliability are improved, but the material thickness must be increased leading to higher costs and detrimental effects on other components

Engineering Contradiction:

Improvestructural integrity of burst capVSAvoidmaterial thickness

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The system is divided into two functional parts: a thick-walled support sleeve that withstands the high filling pressure (800 bar) and provides structural support, and a thin-walled burst member that only needs to withstand the relatively low igniter bursting pressure. This segmentation allows each component to be optimized for its specific function, reducing overall material usage while maintaining reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The support sleeve acts as an intermediary component between the compressed gas tank and the burst member. It mediates the high filling pressure by bearing this load itself, thereby protecting the burst member from experiencing the full 800 bar pressure. The support sleeve transfers only the necessary igniter bursting pressure to the burst member, enabling the use of thinner materials.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If extremely high bursting pressures are used to open the burst cap, then the reliability of opening is improved, but excessive stress and deformation occur causing detrimental effects on other components

Engineering Contradiction:

Improvereliability of burst cap openingVSAvoidexcessive stress and deformation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The support sleeve is designed with specific local qualities (thick-walled structure) at the areas where high filling pressure acts, while the burst member maintains thin walls since it only experiences the controlled igniter bursting pressure. This localized quality distribution allows reliable opening without excessive stress on the overall system.

Inventive Principle:

Principle #3Local quality

3Strength

If the burst member has thick material design to withstand high filling pressures, then the strength and durability are improved, but the manufacturing cost increases

Engineering Contradiction:

Improvestrength of burst memberVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The structural support function is segmented from the burst function. The support sleeve provides the necessary strength to withstand 800 bar filling pressure, while the burst member only needs sufficient strength for the igniter bursting pressure (much lower than 800 bar). This segmentation dramatically reduces the material requirements and manufacturing cost of the burst member while maintaining overall system strength.

Inventive Principle:

Principle #1Segmentation

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 burst device can be opened at a lower bursting pressure, reducing material thickness and costs, while maintaining high collapse pressure and preventing detrimental pressure effects on the igniter, thus enhancing the hybrid inflator's efficiency and safety.

Implementation Method 1

the burst member can be pressurized with compressed gas on its outside in the idle mode

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 2

in the case of operation, the burst cap can be destroyed by a bursting pressure on the igniter compartment side by activating the igniter

Methodology Applied

Scientific EffectBursting pressure: Pressure Increase

Data Source

PatentUS9463766B2Burst device, hybrid inflator, airbag module and vehicle safety system

Publication Date: 2016.10.11 TRW AIRBAG SYSTEMS GMBH

AI summary

The invention relates to a burst device (10), especially for a hybrid inflator (40) including a burst member (20) delimiting an igniter compartment (25) at least in portions on its inside (21), wherein the burst member (20) in the idle mode can be pressurized with compressed gas on its outside (22) and, in the case of operation, the burst member (20) can be destroyed by an igniter compartment side bursting pressure, in accordance with the invention, the burst device (10) includes a support sleeve (30) arranged in the igniter compartment (25) and including an opening (32), the support sleeve (30) including a collar (34) delimiting the opening (33), wherein the burst member (20) rests on the collar (34) of the support sleeve (30) at least in portions upon pressurization from outside.