Steering Column Shear Joint for Retaining Crash Fragments

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Solution Overview

Problem

Existing steering column designs face issues with shear element fragments becoming loose and uncontrolled during crashes, potentially disrupting the steering column's function and posing a risk to vehicle occupants.

Innovation Solution

The steering column incorporates a shear element with a widened portion at the edge of the opening, allowing for plastic deformation and forming a retaining ridge that secures the shear element fragments, preventing them from falling out and ensuring controlled movement during crashes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a shear element is used to connect components in the steering column, then the steering column can be telescoped in a crash event, but the shear element fragments become loose and uncontrolled after shearing off

Engineering Contradiction:

Improvecrash response capabilityVSAvoidfragment control

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The opening is pre-configured with a widened portion at its edge before the crash occurs. This widened portion is prepared in advance to receive and retain the shear element fragments after shearing, preventing them from becoming loose and uncontrolled.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The widened portion of the opening acts as an intermediary structure between the shear element fragments and the steering column components. It provides a controlled retention space that manages the fragments after shearing, preventing harmful loose movement while allowing necessary crash telescoping.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of energy

If the shear element is sheared off during a crash, then the steering column can absorb energy through telescoping, but the loose fragments may disrupt the steering column function and pose injury risk

Engineering Contradiction:

Improvecrash energy absorptionVSAvoidfragment injury risk

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The potential harm of loose shear element fragments is converted into a benefit by using the fragment shearing process to form retaining ridges within the widened opening portions. These ridges securely hold the fragments, transforming what would be a harmful loose debris into a controlled component that aids in energy absorption without posing injury risk.

Inventive Principle:

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

Solution Approach 2:

The widened opening portions are designed in advance to counteract the potential harmful effect of loose fragments. By providing predetermined retention spaces with forming surfaces, the design preemptively prevents fragments from becoming uncontrolled hazards while still allowing the necessary shearing for energy absorption.

Inventive Principle:

Principle #9Preliminary anti-action

3Ease of manufacture

If the opening has a uniform cross-section, then the manufacturing is simpler, but the shear element fragments cannot be retained after shearing

Engineering Contradiction:

Improveopening fabricationVSAvoidfragment retention

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Rather than making the entire opening non-uniform, only localized widened portions are created at specific edge regions of the opening. This local modification maintains most of the simple uniform structure for ease of manufacture while providing the necessary retention capability at critical locations where fragments need to be held.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The opening cross-sectional parameters are changed locally at edge regions to create widened portions, while the main body of the opening retains its original uniform dimensions. This selective parameter change achieves fragment retention without significantly complicating the overall manufacturing process.

Inventive Principle:

Principle #35Parameter changes

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 enhances the operational reliability and safety by securely fixing the shear element fragments, preventing disruptions to the energy absorption mechanism and reducing the risk of injury.

Implementation Method 1

the shear element is plastically deformed in the region of the surfaces to form a retaining ridge which generates a positive connection

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

the shear element is sheared off and divided into two separate shear element fragments

Methodology Applied

Scientific EffectShear stress: Shear Stress

Data Source

PatentUS11970206B2Steering column for a motor vehicle

Publication Date: 2024.04.30 THYSSENKRUPP PRESTA AG

AI summary

A steering column for a motor vehicle may include a crash device that has at least two components that have mutually facing surfaces. The at least two components may be connected to each other by means of a shear element that is arranged in an opening passing at least partially through the components such that the shear element is broken in two if the components move relative to each other. To improve the predetermined breaking connection, the opening may have, in at least one edge region bounding one of the mutually facing surfaces, a widened portion that extends at least over a partial circumferential region and is open towards the respective other surface.