Segmented Gas Generant Grain Assembly Design
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Solution Overview
Problem
Conventional gas generant grains for inflatable restraint devices are large, fragile, and costly to produce, with high breakage rates during processing and use, leading to performance variability and increased manufacturing costs.
Innovation Solution
A segmented gas generant grain assembly comprising multiple symmetric segments arranged circumferentially, each with a high density and no binder, allowing for self-orientation and assembly into a robust, cost-effective structure with reduced breakage and improved manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large monolithic pressed grains are used, then repeatable and well controlled combustion is achieved, but manufacturing cost increases and breakage occurs during processing and use
Solution Approach 1:
The gas generant grain is divided into multiple smaller pressed segments (typically 2-10 segments) that are assembled together to form the complete grain structure. Each segment is pressed separately using smaller, less expensive equipment, then joined using binder material to create the final monolithic-like grain that provides controlled combustion while reducing manufacturing costs and breakage risk
2Shape
If large monolithic pressed grains are used, then desired geometry is achieved, but breakage occurs during processing, shipping, or product life
Solution Approach 1:
The grain is constructed from multiple smaller pressed segments that are assembled together. These segments are individually more robust and less prone to breakage than a single large monolithic grain. The segments are joined using binder material that creates strong bonds while allowing the overall grain structure to be more resilient to stress and handling during processing, shipping, and product life
Solution Approach 2:
The grain structure combines pressed generant segments with binder material to create a composite structure. The binder material (such as polymeric binders, waxes, or resins) provides structural integrity and holds the pressed segments together, creating a composite grain that maintains desired geometry while being more resistant to breakage than purely monolithic pressed grains
3Stability of the object's composition
If large pressed grains are used, then unitary monolithic structure is achieved, but processing time increases and equipment cost increases
Solution Approach 1:
Instead of pressing one large monolithic grain that requires expensive, slow hydraulic press equipment, the invention divides the grain into multiple smaller segments that can be pressed simultaneously or in rapid sequence using smaller, faster pressing equipment. This segmentation enables higher production rates and reduces equipment costs while the segments are subsequently assembled to create the complete grain structure
Solution Approach 2:
The pressed segments are prepared in advance as pre-formed components with specific geometries and combustion characteristics. These pre-prepared segments are then assembled using binder material to create the final grain structure, allowing for more efficient manufacturing workflows and reduced processing time compared to forming one large monolithic grain in a single pressing operation
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 segmented design enhances robustness, reduces breakage rates, and lowers manufacturing costs while maintaining high performance characteristics, such as rapid burn rates and high gas yields, with improved safety and reliability in inflatable restraint systems.
Implementation Method 1
sequentially introducing the respective gas generant segments into the round receptacle, where each symmetric segment self-orients to be arranged circumferentially within the round receptacle
Implementation Method 2
a pyrotechnic gas generant to inflate an airbag cushion
Data Source
AI summary
Pressed and segmented gas generant grain assemblies formed from a plurality of symmetric gas generant pieces or segments are disclosed. The symmetric pieces or segments are arranged circumferentially to define a substantially round, segmented body. In certain variations, the symmetric segments are substantially free of polymeric binder and have a high density. The segmented pressed grain assemblies are more robust and less expensive to manufacture, while still exhibiting desired combustion performance. Methods of making such segmented gas generant grain assemblies are also provided.