Knee Airbag Cover Opening Control for Slim Cockpit Restraint
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Solution Overview
Problem
The slim-type cockpit design reduces the distance between the cockpit and the occupant, causing delayed knee restraint and insufficient space for the knee airbag, necessitating an increase in airbag cushion volume, which further exacerbates the space issue.
Innovation Solution
A knee airbag system with an airbag housing, cover, and opening limiting unit that limits the upper opening degree of the cover using a connection part, preventing sagging and allowing quick deployment without increasing the airbag cushion package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the airbag cushion volume is increased to quickly restrain the occupant's knees, then the knee restraint speed is improved, but the airbag package volume increases and the mounting space becomes insufficient
Solution Approach 1:
The cover is divided into a fixed lower portion and a movable upper portion that can separate during deployment. This segmentation allows the airbag cushion to deploy quickly through the separated upper portion while the lower portion remains compact within the housing, achieving fast restraint without increasing overall package volume.
Solution Approach 2:
The cover transitions from a static closed structure to a dynamic partially open structure during deployment. The upper portion rotates or separates to create a deployment path, then returns to a limited open position, enabling rapid airbag deployment while maintaining a compact stowed configuration.
2Speed
If the cover opening degree is increased to allow faster airbag deployment, then the deployment speed is improved, but the airbag cushion may sag and the structural control is worsened
Solution Approach 1:
Different portions of the cover have different functional qualities: the lower portion is fixed to provide structural support and prevent sagging, while the upper portion is movable to enable rapid deployment. This local differentiation allows the system to achieve both fast deployment and shape stability.
Solution Approach 2:
The opening limiting unit is pre-configured to control the cover's opening degree. This preliminary structural arrangement ensures that when the cover opens, it does so to a predetermined angle that allows rapid deployment while preventing excessive opening that would cause airbag sagging.
3Stability of the object's composition
If the connection part is made more rigid to prevent airbag sagging, then the shape stability is improved, but the cover opening speed is reduced
Solution Approach 1:
The connection part uses a dynamic hinge structure that allows rapid rotation during deployment but maintains structural control throughout the motion. The hinge provides the necessary rotational freedom for fast opening while the connection geometry and opening limits ensure the cover does not open beyond a safe angle, preventing sagging.
Data Source
AI summary
A knee airbag is proposed. The knee airbag is configured to be applied to a slim-type cockpit design and to quickly restrain the knees of an occupant without increasing a package of an airbag cushion to reduce a risk of injuries to the occupant. The knee airbag includes an airbag housing provided at a lower end of a cockpit, and including an airbag cushion located toward an occupant, a cover assembled to the airbag housing in a shape of covering the airbag cushion, wherein in deployment of the airbag cushion, a lower portion of the cover is fixed to the airbag housing and an upper portion thereof is separated and opened from the airbag housing, and an opening limiting unit configured to limit an opening degree of the upper portion of the cover.