Vehicle Knee Bolster with U-Bracket and Foam

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Solution Overview

Problem

Conventional knee bolsters for vehicles fail to comply with the pedestrian protection regulations of the reinforced North American NCAP, particularly in absorbing knee loads, as they are designed to deform and absorb loads inefficiently, leading to inadequate protection for passengers.

Innovation Solution

A knee bolster incorporating a U-shaped bracket and shock-absorbing foam, where the U-shaped bracket and foam deform to absorb knee loads, with the foam sliding along the bracket to distribute and lock the load, enhancing the absorption efficiency and compliance with NCAP regulations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the conventional knee bolster bracket deforms to absorb knee load, then the structure is simple, but the knee load absorption efficiency is insufficient and cannot comply with reinforced NCAP regulations

Engineering Contradiction:

Improveknee load absorption efficiencyVSAvoidstructure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent combines a U-shaped bracket (metal structure) with shock-absorbing foam (polymer material) to create a composite knee bolster system. The bracket provides structural support and initial load bearing, while the foam material provides progressive energy absorption through compression, achieving superior knee load absorption efficiency that meets reinforced NCAP regulations requiring knee load not exceeding 2.8 kN.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The knee bolster is divided into distinct functional segments: the U-shaped bracket structure (providing framework and mounting points) and the shock-absorbing foam (providing energy absorption). This segmentation allows each component to be optimized for its specific function while working together to achieve overall performance compliance with safety regulations.

Inventive Principle:

Principle #1Segmentation

2Strength

If a combined structure of U-shaped bracket and shock-absorbing foam is used, then knee load absorption efficiency improves, but production cost and manufacturing complexity increase

Engineering Contradiction:

Improveknee load absorption efficiencyVSAvoidproduction process simplicity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent merges the U-shaped bracket and shock-absorbing foam into an integrated knee bolster assembly where the foam is positioned within or attached to the bracket structure. This combining approach achieves superior knee load absorption (meeting 2.8 kN requirement) while the unified design simplifies installation and assembly processes, offsetting some manufacturing complexity through reduced part count and simplified integration.

Inventive Principle:

Principle #5Merging (Combining)

3Object-affected harmful factors

If the knee bolster allows deep knee movement into the lower instrument panel, then the structure is simple, but the passenger protection is insufficient and airbag effectiveness is reduced

Engineering Contradiction:

Improvepassenger protection levelVSAvoidknee bolster structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The shock-absorbing foam is pre-positioned within the U-shaped bracket to provide immediate cushioning when knee impact occurs. This beforehand cushioning prevents deep knee movement into the lower instrument panel and distributes crash energy evenly, protecting the passenger's knees and maintaining proper positioning for airbag effectiveness without requiring complex active control systems.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent converts the harmful knee impact force into beneficial energy absorption through the controlled deformation of the shock-absorbing foam. The foam compresses under knee load, transforming the harmful crash energy into deformation work, thereby protecting the passenger and reducing the harmful effects of the impact while maintaining structural integrity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 combined structure effectively absorbs knee loads by dual deformation mechanisms, achieving compliance with NCAP regulations, reducing production costs, and simplifying the design, while providing improved protection for passengers of varying leg lengths.

Implementation Method 1

a shock absorbing foam mounted in the U-shaped bracket, being deformed by the external force during the accident, and sliding along inner surface of the U-shaped bracket, thus secondarily absorbing the knee load of the passenger

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

the U-shaped bracket and foam deform to absorb knee loads

Methodology Applied

Scientific EffectDeformation: Deformation

Data Source

PatentUS8333407B2Knee bolster for vehicles

Publication Date: 2012.12.18 HYUNDAI MOTOR CO LTD

AI summary

A knee bolster for vehicles, which is placed inside a lower instrument panel of a vehicle and is mounted to a cowl cross bar and relieves shock applied to knees of a passenger in case of an accident, may include a U-shaped bracket mounted to the cowl cross bar and bent to form a U-shape to be deformed by an external force during the accident, thus primarily absorbing knee load of the passenger, and a shock absorbing foam mounted in the U-shaped bracket, being deformed by the external force during the accident, and sliding along inner surface of the U-shaped bracket, thus secondarily absorbing the knee load of the passenger.