Gas Generator Rupturable Plate Breaking Device
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas generators for airbag systems face reliability issues due to complex operations and inefficient gas flow control, leading to reduced airbag expansion speed and performance.
Innovation Solution
A gas generator design with a cylindrical housing, an ignition device chamber, a gas inflow chamber, and a pressurized gas chamber, featuring a rupturable plate and a breaking device with a rod and enlarged-diameter portion, which controls gas flow by ensuring the cross-sectional area of the second annular passage is the smallest, maintaining reliable actuation and gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex multi-stage operation is used to break the burst disk and hold it, then the burst disk can be reliably broken, but the device complexity increases and reliability decreases
Solution Approach 1:
The breaking device is segmented into distinct functional portions: a base that moves axially, a rod that extends from the base, an enlarged-diameter portion at the distal end for punching, and a rod main body portion for forming the gas passage. This segmentation allows each portion to perform its specific function independently, simplifying the overall operation while maintaining reliability.
Solution Approach 2:
The breaking device performs the burst disk breaking action as a preliminary step before gas flow control. The base moves by a predetermined length to position the enlarged-diameter portion, which then punches through the burst disk. This preliminary breaking action prepares the system for subsequent gas flow through the controlled passage, eliminating the need for complex multi-stage operations.
2Productivity
If the cross-sectional area of gas passages is not optimized, then manufacturing is simpler, but gas flow control and airbag expansion speed deteriorate
Solution Approach 1:
The gas passage system employs local quality optimization by creating different cross-sectional areas at different locations. The second annular passage between the rod main body portion and annular fixing portion has a specifically controlled cross-sectional area that is smaller than other passages. This localized area control ensures optimal gas flow velocity and pressure distribution, enhancing airbag expansion speed without requiring complex overall redesign.
Solution Approach 2:
The invention changes the geometric parameter of the gas passage cross-sectional area to optimize gas flow. By setting the cross-sectional area of the second annular passage to be the smallest, the system controls gas flow rate and pressure distribution. This parameter optimization directly improves airbag expansion performance while maintaining a relatively simple structural design.
3Reliability
If a rupturable plate is fixed to an annular fixing portion, then gas flow control is improved, but the device complexity increases
Solution Approach 1:
The rupturable plate is merged with the annular fixing portion to form an integrated structure. The fixing portion extends radially inward from the inner circumferential wall, and the rupturable plate is fixed to this portion. This merging eliminates the need for separate mounting mechanisms, reducing device complexity while maintaining reliable gas flow control through the passage between the rod and the fixing portion.
Solution Approach 2:
The annular fixing portion serves multiple functions: it provides structural support for the rupturable plate, defines the boundary of the gas passage, and works with the rod main body portion to control gas flow. This multi-functionality reduces the number of separate components needed, simplifying the overall device structure while ensuring reliable gas flow control.
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 enhances the reliability and performance of airbag deployment by controlling gas flow effectively, ensuring consistent and efficient pressurized gas discharge, thereby maintaining the reliability of airbag actuation over the vehicle's service period.
Implementation Method 1
when the base of the breaking device moves in the axial direction by the length L during actuation, the enlarged-diameter portion of the breaking device being positioned inside the pressurized gas chamber after punching out the rupturable plate from the annular fixing portion
Implementation Method 2
when a pressurized gas flows from the pressurized gas chamber to the gas discharge port, the pressurized gas passing through a gas passage to be discharged from the gas discharge port
Data Source
AI summary
The present invention provides a gas generator, includingin a cylindrical housing, an ignition device chamber provided with an ignition device, a gas inflow chamber having a gas discharge port and a pressurized gas chamber being arranged in the above order from the first end,a rupturable plate closing between the pressurized gas chamber and the gas inflow chamber and being fixed to an annular fixing portion,a breaking device for the rupturable plate being arranged between the ignition device chamber and the gas inflow chamber,the breaking device including a base, a rod main body which extends from the base towards the rupturable plate, and an enlarged-diameter portion at a distal end of the rod main body, and during actuation, the base moving in the axial direction, the enlarged-diameter portion being positioned inside the pressurized gas chamber after punching out the rupturable plate, and the rod main body portion being positioned so as to oppose the annular fixing portion in a radial direction,a pressurized gas passing through a gas passage and then is discharged from the gas discharge port, the gas passage including a first annular passage in which a width between the enlarged-diameter portion and the annular fixing portion varies and a second annular passage between the rod main body portion and the annular fixing portion,a cross-sectional area of the second annular passage being the smallest among the cross-sectional area of the second annular passage, an area of a minimum width portion of the first annular passage and a total opening area of the gas discharge port, andQ<(A2−A1) being satisfied when Q denotes the cross-sectional area of the second annular passage, A1 denotes an area of the punched-out rupturable plate and A2 denotes the area of the minimum width portion of the first annular passage.