Driver Airbag Cushion Layout for Yoke Steering Wheel Restraint
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Solution Overview
Problem
Conventional driver seat airbag devices face challenges in fully restraining the head and chest of occupants, especially when equipped with non-circular steering wheels, as the airbag cushion may not expand quickly enough to avoid impacting the steering wheel and may tilt or collapse due to the absence of an upper rim, failing to provide adequate protection.
Innovation Solution
A driver seat airbag device configuration featuring a chest protecting cushion that expands behind the steering wheel and a head protecting cushion that deploys adjacent to and above the chest cushion, with the head cushion extending to the instrument panel to absorb loads independently of the steering wheel, ensuring full restraint of the head and chest. The head cushion can have a larger volume than the chest cushion, with a border set near the steering wheel hub to accommodate non-circular steering wheel designs, and can deploy later than the chest cushion to reduce load on the head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a large capacity airbag cushion is used to protect the occupant, then the protection capability is improved, but the expansion speed decreases making it difficult to quickly enter the narrow space between the steering wheel and the chest
Solution Approach 1:
The airbag cushion is divided into two separate cushions: a chest protecting cushion with smaller volume for rapid expansion into the narrow space, and a head protecting cushion with larger volume for comprehensive protection. This segmentation allows each cushion to be optimized for its specific function, resolving the contradiction between volume and expansion speed.
2Adaptability or versatility
If a yoke steering wheel design is used to modernize the steering wheel, then the steering wheel design flexibility is improved, but the contact range with the airbag cushion is reduced causing the airbag to tilt or collapse
Solution Approach 1:
The airbag system is segmented into two functional cushions with distinct deployment zones. The chest protecting cushion deploys behind the steering wheel while the head protecting cushion extends to the instrument panel, creating multiple contact points that stabilize the airbag structure even when the steering wheel has reduced contact areas.
Solution Approach 2:
The head protecting cushion extends in the vertical dimension from the chest cushion up to the instrument panel surface, creating a three-dimensional protective structure. This vertical extension provides additional support points that prevent the airbag from tilting or collapsing, compensating for the reduced horizontal contact range of yoke steering wheels.
3Volume of moving object
If the airbag cushion is positioned close to the steering wheel for compact design, then the device compactness is improved, but the expansion time increases making it difficult to prevent impact with the steering wheel
Solution Approach 1:
The compact airbag device is segmented into two independently deployable cushions. The chest protecting cushion is positioned to rapidly expand into the narrow space behind the steering wheel, while the head protecting cushion deploys adjacent to and above it. This segmentation allows the system to maintain compact storage while achieving rapid deployment of the critical chest protection function.
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
This configuration allows for stable and effective restraint of both the chest and head of the occupant, even with non-circular steering wheels, by ensuring the airbag cushions can expand into the available space and absorb loads without relying on the steering wheel, thereby preventing the head from tilting or the airbag from collapsing.
Implementation Method 1
the head protecting cushion can efficiently absorb a load from the head without being dependent on the steering wheel
Data Source
AI summary
A driver seat airbag device restrains an occupant seated in a driver seat of a vehicle, and includes, a chest protecting cushion that expands and deploys behind a yoke steering wheel; and a head protecting cushion that expands and deploys adjacent to and above the chest protecting cushion. The head protecting cushion extends from an upper portion of the chest protecting cushion to an upper surface of an instrument panel when expanded and deployed, and contacts and restrains the head of the occupant from the front.