Knee Airbag Mounting Layout for Downward Projection Control
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Solution Overview
Problem
Existing knee protection airbag devices face challenges in mounting due to space constraints and difficulty in ensuring proper downward projection and rearward upward deployment of the airbag, especially in vehicles with limited space above the mounted portion.
Innovation Solution
The knee protection airbag device is designed with an attachment base that allows for easy mounting using fastening bolts and attachment bolts with axial directions parallel to the front-rear direction, enabling the airbag to project downward and deploy rearward and upward, with the airbag cover forming a projection opening to facilitate proper inflation and stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the fastening bolt is passed through from bottom to top of the attachment base and attachment seats are arranged on top side, then the airbag device can be securely fastened to the vehicle body member, but a work space is required above the mounted portion for turning nuts which is not available in vehicles with limited space
Solution Approach 1:
The patent inverts the conventional mounting direction by passing the fastening bolt from the top side to the bottom side of the attachment base, and positioning the attachment seats on the bottom side to engage with the vehicle body member. This inversion eliminates the need for work space above the mounted portion, as nuts can be turned from below the vehicle floor, thereby resolving the contradiction between secure fastening and ease of mounting in space-constrained vehicles.
2Device complexity
If the folded portion of the airbag is arranged behind the body portion of the inflator, then the airbag structure is simplified, but the airbag tends to project rearward during inflation making it difficult to achieve proper downward projection and rearward upward deployment
Solution Approach 1:
The patent introduces a reversing portion as an intermediary component between the base portion and the inflation body portion. This reversing portion extends downward from the base portion and reverses upward during inflation, acting as a mediator that guides the inflation process. It ensures the airbag first projects downward from the mounted portion and then deploys rearward and upward, preventing direct rearward projection while maintaining structural simplicity.
3Strength
If the attachment base is designed with attachment seats on both left and right sides for attachment bolts with axial directions parallel to up-down direction, then the airbag device can be firmly attached to the vehicle body member, but the mounting process becomes complex requiring precise positioning and multiple fastening operations
Solution Approach 1:
The patent designs the attachment base with attachment seats that can accommodate both attachment bolts and the fastening bolt of the inflator. The attachment seats are positioned on the bottom side of the attachment base, allowing all fastening operations to be performed from below the vehicle floor. This multi-functional design simplifies the mounting process by enabling firm attachment through a unified bottom-side fastening approach, reducing positioning complexity and streamlining the overall mounting procedure.
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 design facilitates easier mounting and ensures accurate downward projection and rearward upward deployment of the airbag, stabilizing the expansion behavior and preventing rotational issues during inflation, while allowing for precise positioning of the inflation body portion.
Implementation Method 1
an inflator that supplies inflation gas to the airbag
Implementation Method 2
an airbag cover that covers the airbag which is folded and accommodated, in which the airbag cover is pushed by the airbag being inflated to form a projection opening through which the airbag projects
Implementation Method 3
a fastening bolt projecting outside the airbag from the body portion and fastened to the attachment base
Implementation Method 4
attachment seats that are arranged on left and right sides of the holding seat and are attached to the vehicle body member using attachment bolts of which axial directions are parallel to a front-rear direction
Data Source
AI summary
A knee protection airbag device includes an airbag, an inflator, an airbag cover, and an attachment base which holds those and is to be attached to a vehicle body member. The attachment base includes a holding seat which is disposed in front of a body portion of the inflator and a folded portion of the airbag, and holds the body portion and the airbag attached by a fastening bolt of the inflator, and attachment seats which are arranged on left and right sides of the holding seat and are attached to the vehicle body member. The airbag cover covers a vicinity of the airbag folded and the body portion of the inflator on a rear side of the attachment base, is attached to the attachment base due to the fastening bolt being fastened, and provides a projection opening on a bottom side of the airbag cover.