Vehicle Occupant Protection System with Inflation Limiting Structure
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Solution Overview
Problem
Conventional vehicle occupant protection systems face challenges in efficiently reducing airbag inflation force and effectively restraining the inertial motion of the occupant's head during collisions, as the airbag inflates from the lap belt, leading to delayed protection and insufficient restraint.
Innovation Solution
A vehicle occupant protection system featuring a shoulder belt, a lap belt, an upper airbag housed in the shoulder belt, a lower airbag housed in the lap belt, and an inflation limiting structure within the lower airbag, which limits inflation in the back-and-forth direction, allowing the airbags to inflate and vertically contact each other, with the upper part of the lower airbag bending forward to reduce inflation force and enhance head restraint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air bag is inflated from the lap belt toward the occupant, then the air bag can be deployed to protect the occupant, but the inflation force applied to the occupant is excessive and the response time to restrain head inertial motion is delayed
Solution Approach 1:
The protection system is divided into two separate air bags: an upper air bag housed in the shoulder belt and a lower air bag housed in the lap belt. This segmentation allows each air bag to be positioned optimally and inflate in a controlled manner, with the upper air bag providing immediate head protection and the lower air bag providing abdominal protection, thereby reducing excessive inflation force on any single area while maintaining overall protection effectiveness.
Solution Approach 2:
The air bags are configured to inflate not only in the forward direction but also in the vertical dimension. The upper air bag inflates from the shoulder belt downward and forward, while the lower air bag inflates from the lap belt upward and forward. This multi-dimensional inflation approach allows the air bags to reach the occupant more quickly and provide protection without requiring excessive forward inflation force.
2Reliability
If the air bag is inflated from the lap belt toward the occupant, then the air bag can be deployed, but the distance from the lap belt to the occupant's head is long causing delayed response time
Solution Approach 1:
By segmenting the protection system into upper and lower air bags positioned at different locations (shoulder belt and lap belt respectively), the system eliminates the need for a single long-distance inflation path. The upper air bag positioned near the shoulder provides immediate proximity protection for the head and upper body, significantly reducing the response time required to restrain head inertial motion during a collision.
Solution Approach 2:
The upper air bag is pre-positioned in the shoulder belt, which is already in close proximity to the occupant's upper body and head. This preliminary positioning allows the air bag to inflate immediately toward the occupant without requiring long-distance deployment, thereby providing rapid response time to restrain head inertial motion from the outset of the collision event.
3Reliability
If the lower air bag inflates freely in the back-and-forth direction, then the air bag can expand to provide protection, but the inflation force applied to the occupant's chest and abdominal area is excessive
Solution Approach 1:
The lower air bag incorporates a localized weak portion at its front end, creating a region of reduced strength specifically at the area that will contact the occupant's chest and abdominal region. This local quality modification allows the air bag to inflate effectively while automatically limiting the inflation force applied to sensitive areas, providing abdominal protection without excessive force through targeted structural design.
Solution Approach 2:
The weak portion structure in the lower air bag acts as a pre-designed cushioning element that yields under inflation pressure. This beforehand cushioning mechanism ensures that when the air bag inflates, the front end naturally deforms to reduce peak inflation forces before they can be transmitted to the occupant's chest and abdominal area, providing protected cushioning in advance.
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 system effectively reduces the inflation force applied to the occupant and improves head restraint by allowing the airbags to deploy and interact in a manner that minimizes the impact on the chest and abdominal area, ensuring quicker and more effective protection during collisions.
Implementation Method 1
an upper part of the inflated lower air bag positioned above the inflation limiting structure is pressed by the upper air bag and bends toward the front of the vehicle at the inflation limiting structure
Data Source
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AI summary
A vehicle occupant protection system includes: a seat belt apparatus including a shoulder belt (11) and a lap belt (13); an upper air bag (27, 113); a lower air bag (29, 67, 73, 83); and an inflation limiting structure (37, 53, 55, 57, 75, 85) which is provided in the lower air bag and limits inflation of a part of the lower air bag in a vehicle back-and-forth direction when the lower air bag is inflated. When the vehicle collision is detected or predicted, the upper and lower air bags are inflated and vertically come into contact with each other. Further, an upper part (41, 71, 79, 91) of the inflated lower air bag positioned above the inflation limiting structure is pressed by the upper air bag and bends toward the front of the vehicle at the inflation limiting structure.