Steering Column Strap Buckling Control via Segmented Tabs

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Solution Overview

Problem

Existing steering column energy absorption strap designs often result in inconsistent running load performance due to buckling and binding of straps during a collapse event, as the outer strap is fully captured on both sides, restricting freedom and causing undesirable binding.

Innovation Solution

A buckling control assembly is introduced, featuring an inner and outer energy absorption strap with a strap constraining structure on one side of the outer strap to inhibit buckling, allowing the outer strap to buckle freely and preventing binding, while maintaining energy absorption efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the outer energy absorption strap is fully captured on both sides for the entire length of the collapse event, then the strap structure is stable and constrained, but the strap cannot buckle freely causing binding against the inner strap and inconsistent running load performance

Engineering Contradiction:

Improvestrap constraint stabilityVSAvoidrunning load consistency

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The constraint structure is segmented into multiple discrete tabs spaced along the strap length rather than continuous full capture. This segmentation allows localized buckling freedom between tabs while maintaining overall structural constraint, resolving the contradiction between stability and buckling freedom.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The constraint is applied locally at specific tabs rather than uniformly along the entire strap length. This creates zones of constraint (at tabs) and zones of freedom (between tabs), allowing the strap to buckle in controlled locations while maintaining stability at constraint points.

Inventive Principle:

Principle #3Local quality

2Strength

If the outer energy absorption strap is fully captured on both sides, then structural constraint is maximized, but buckling freedom is restricted causing binding and energy absorption inconsistency

Engineering Contradiction:

Improvestructural constraintVSAvoidenergy absorption efficiency

Core Design Contradiction:

StrengthVSLoss of energy

Solution Approach 1:

The continuous constraint is segmented into discrete tabs, creating a balance between structural constraint (at tab locations) and buckling freedom (between tabs). This allows the strap to absorb energy through controlled buckling while maintaining overall structural integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of full continuous constraint, partial constraint is applied through spaced tabs. This partial action provides sufficient structural constraint while allowing enough buckling freedom to maintain energy absorption efficiency, avoiding the excessive constraint that would cause binding.

Inventive Principle:

Principle #16Partial or excessive action

3Device complexity

If the outer strap is completely captured on both sides, then the strap assembly is compact and constrained, but the strap binds against the inner strap during buckling causing inconsistent load performance

Engineering Contradiction:

Improvestrap assembly simplicityVSAvoidload path consistency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The constraint structure uses segmented tabs rather than continuous capture, maintaining compact assembly while creating gaps that prevent binding during buckling. The segmentation allows the strap to move freely in unconstrained regions while remaining compact overall.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The tabs act as intermediary constraint points that guide buckling without causing binding. These intermediate structures mediate between the need for constraint and the need for buckling freedom, preventing direct contact and binding between inner and outer straps.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 critical buckling force and prevents binding, ensuring a consistent and smooth load path over a larger displacement range during a collapse event, improving energy absorption performance compared to fully constrained strap assemblies.

Implementation Method 1

During the collapse event, either or both straps buckle because of the design properties of the strap(s). The buckling control assembly is designed to control the buckling of the outer energy absorption strap during a collapse event.

Methodology Applied

Scientific EffectBuckling:

Implementation Method 2

energy absorption straps are utilized to partially reduce an occupant's kinetic energy during a collapse event of the steering column

Methodology Applied

Scientific EffectEnergy absorption:

Data Source

PatentUS10471981B2Buckling control assembly for a steering column energy absorption strap assembly

Publication Date: 2019.11.12 STEERING SOLUTIONS IP HOLDING CORP

AI summary

A buckling control assembly for a steering column energy absorption strap assembly is provided. The buckling control assembly includes an inner energy absorption strap operatively coupled to a steering column jacket. Also included is an outer energy absorption strap surrounding at least a portion of the inner energy absorption strap and operatively coupled to the steering column jacket. Further included is a strap constraining structure disposed on a constraint side of the outer energy absorption strap to inhibit buckling of the outer energy absorption strap in a first direction, the outer energy absorption strap having a free side unconstrained to accommodate buckling of the outer energy absorption strap.