Gas Generator Spring Layout for Stable Combustion in Thin Housings
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Solution Overview
Problem
Existing gas generators face challenges in achieving stable combustion while reducing weight and manufacturing costs, as decreasing the housing thickness for weight reduction can compromise pressure resistance performance.
Innovation Solution
A gas generator design featuring a housing with a partition member and a coil spring that biases the gas generating agent away from the partition, maintaining a specific volume ratio to ensure stable combustion and reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the housing thickness is decreased to reduce weight and manufacturing cost, then the weight and cost are reduced, but the pressure resistance performance of the housing is compromised
Solution Approach 1:
The coil spring is pre-compressed between the partition member and the gas generating agent, creating a preliminary mechanical support structure. This pre-compression establishes a stable high-pressure environment before combustion occurs, allowing the housing to operate at thinner gauges while maintaining adequate pressure resistance during activation.
Solution Approach 2:
The invention optimizes the volume ratio parameter (V2/V1) between the non-filled space and gas generating agent accommodation chamber to a specific range (0.05≤V2/V1≤0.32). This parameter optimization enables the system to achieve stable combustion and adequate pressure resistance with reduced housing thickness, directly addressing the weight-strength contradiction.
2Ease of manufacture
If the housing thickness is decreased to reduce weight and manufacturing cost, then the manufacturing cost is reduced, but the pressure resistance performance of the housing is compromised
Solution Approach 1:
The pre-compressed coil spring creates a preliminary support structure that compensates for the reduced structural strength of thinner housing walls. This preliminary mechanical support system enables the use of thinner, less expensive housing materials while maintaining adequate pressure resistance during gas generator activation.
Solution Approach 2:
By optimizing the volume ratio parameter (V2/V1) to a specific range, the invention achieves stable combustion characteristics that work effectively with reduced housing thickness. This parameter optimization allows manufacturers to use thinner, less expensive materials while maintaining performance requirements.
3Weight of moving object
If the pressure in the housing is lowered to enable weight reduction, then the housing thickness can be decreased, but the stable and persistent combustion of the gas generating agent becomes difficult to achieve
Solution Approach 1:
The coil spring is pre-compressed to establish a stable high-pressure environment before combustion initiates. This preliminary compression ensures that adequate pressure is maintained throughout the combustion process, enabling stable and persistent burning of the gas generating agent even in a lighter, thinner-housed system.
Solution Approach 2:
The optimization of the volume ratio parameter (V2/V1) creates optimal combustion conditions that maintain stable burning characteristics. This parameter control ensures reliable operation while allowing the use of reduced housing thickness for weight reduction.
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 design achieves stable operations, weight reduction, and lower manufacturing costs by optimizing the internal pressure environment for persistent gas generating agent combustion.
Implementation Method 1
the coil spring fixes the gas generating agent in the inside of the gas generating agent accommodation chamber by biasing the gas generating agent toward the one end of the housing while the coil spring keeps the gas generating agent away from the partition member
Implementation Method 2
an igniter being ignited in response to power feed caused by a control unit at the time of collision of a vehicle to thereby burn a gas generating agent with flame caused by the igniter and instantaneously generate a large amount of gas
Implementation Method 3
generated gas passes through the filter, and thereafter gas is discharged to the outside through the gas discharge opening
Data Source
AI summary
A gas generator includes an igniter, a partition member that axially partitions a space in the inside of a housing into a gas generating agent accommodation chamber and a filter chamber, and a gas generating agent and a coil spring accommodated in the gas generating agent accommodation chamber. The coil spring is interposed between the partition member and the gas generating agent and fixes the gas generating agent while it keeps the gas generating agent away from the partition member. V1 represents a volume of the gas generating agent accommodation chamber and V2 represents a volume of a non-filled space which is a space where the gas generating agent is not arranged in the inside of the gas generating agent accommodation chamber as a result of arrangement of the coil spring, where V1 and V2 satisfy a condition of 0.05≤V2/V1≤0.32.