Gas Generator Filter Retainer Using Pneumatic Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In air bag systems, short passes of high-temperature combustion gas into the air bag without filtration can injure passengers, and existing solutions either fail to reduce the weight of the gas generator or complicate the assembly process.
Innovation Solution
A gas generator design featuring a cylindrical filter supported by a retainer with a specific shape, including a larger and smaller diameter portion with vent holes, ensures that combustion gases pass through the filter by utilizing internal pressure to maintain contact and prevent short passes, allowing for a reduction in filter size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filter covers a wide surface area to prevent short passes, then the reliability of preventing high-temperature gas from entering the air bag is improved, but the weight of the filter increases
Solution Approach 1:
The retainer utilizes the dynamic pressure of combustion gas to press the filter against the housing ceiling during activation. The filter is held in place by gas pressure rather than mechanical fasteners, allowing for a smaller, lighter filter design while maintaining sealing effectiveness during the critical activation phase
Solution Approach 2:
The system employs pneumatic pressure from the combustion gas to achieve the sealing function. The high-pressure gas automatically presses the filter against the housing, eliminating the need for heavy mechanical retention structures and enabling weight reduction while ensuring reliable short pass prevention
2Reliability
If the filter is made larger to ensure complete filtration, then the filtering function is improved, but the size of the gas generator increases
Solution Approach 1:
The filter positioning mechanism transitions from static mechanical support to dynamic pressure-based retention. During activation, combustion gas pressure automatically presses the filter into sealing contact with the housing, ensuring complete filtration coverage with a smaller filter element
Solution Approach 2:
The system changes the operational state of the filter from a statically supported component to a dynamically pressurized component. The filter achieves optimal sealing pressure through combustion gas pressure, allowing reduced filter size while maintaining filtration effectiveness
3Reliability
If a complex retainer structure is used to secure the filter, then the reliability of filter positioning is improved, but the device complexity increases
Solution Approach 1:
The retainer system utilizes the combustion gas pressure itself to perform the sealing and positioning function. The high-pressure gas automatically presses the filter against the housing ceiling, eliminating the need for complex mechanical fastening structures and simplifying the overall device design
Solution Approach 2:
The invention extracts the sealing function from complex mechanical retention structures and transfers it to the combustion gas pressure. This simplifies the retainer design to basic support elements while maintaining reliable filter positioning through pneumatic pressure
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 solution effectively prevents short passes while reducing the size and weight of the filter and the entire gas generator, simplifying the manufacturing process and maintaining filtering and cooling functions.
Implementation Method 1
utilizing internal pressure to maintain contact and prevent short passes
Implementation Method 2
a filter serving as a constitutional component of a gas generator used in an air bag system has a function for cooling high-temperature combustion gas
Implementation Method 3
a filter serving as a constitutional component of a gas generator used in an air bag system has a function for filtering solid matter contained in the combustion gas
Data Source
AI summary
The present invention provides a gas generator including a housing formed by a closure shell and a diffuser shell having a gas discharge port,a combustion chamber provided inside the housing and charged with a gas generating agent,an ignition device to ignite and burn the gas generating agent inside the combustion chamber,a cylindrical filter disposed to face the gas discharge port and having an annular upper surface press-contacting a ceiling surface of the housing,a retainer disposed inside the combustion chamber to support the cylindrical filter,the retainer being substantially a cylinder, having a larger diameter portion and a smaller diameter portion, that is provided with a vent hole, as well as an annular surface portion provided between the larger diameter portion and the smaller diameter portion,an outer peripheral surface of the larger diameter portion abutting against an inner wall surface of the housing before activation and press-contacting the inner wall surface of the housing in activation, the annular surface portion press-contacting an annular lower surface of the cylindrical filter and an outer peripheral surface of the smaller diameter portion abutting against an inner peripheral surface of the cylindrical filter,a lower end portion of the larger diameter portion press-contacting the inner peripheral surface of the housing.