Steering Wheel Spoke Projection for Crash Folding

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Solution Overview

Problem

Modern steering wheels for passenger cars face challenges in designing spokes that can withstand high long-term stress, flexural stiffness requirements, and crash test resistance without breaking or shearing at the steering wheel rim.

Innovation Solution

The design incorporates a projection at the first spoke end that restricts tilting towards the central area, forming a hinge-like attachment area that allows the spoke to fold and yield during crashes, preventing shearing or breaking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the spoke is designed to bend or buckle during crash, then the flexural stiffness requirement is met, but the spoke may break at the connecting area to the steering wheel rim

Engineering Contradiction:

Improveflexural stiffnessVSAvoidspoke integrity at rim connection

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The spoke is segmented into multiple sections with different structural characteristics. The first spoke section includes a projection that creates a hinge-like attachment area, while the second spoke section has a different main construction direction. This segmentation allows controlled bending at specific locations while maintaining integrity at critical connection points.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The projection at the first spoke end creates a localized hinge mechanism with specific geometric properties (angles α and β between 30°-70° and 40°-80° respectively). This local structural feature enables controlled tilting and folding behavior during crash while preventing uncontrolled breaking at the rim connection area.

Inventive Principle:

Principle #3Local quality

2Reliability

If the projection restricts tilting of the spoke, then the spoke is prevented from breaking, but material usage increases

Engineering Contradiction:

Improvespoke durabilityVSAvoidmaterial consumption

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The projection dimensions are optimized with specific parameter ranges: angle α between 30°-70°, angle β between 40°-80°, and the projection extends transversely over less than one third of the spoke section width. These parameter optimizations achieve the required protective function while minimizing material consumption.

Inventive Principle:

Principle #35Parameter changes

3Shape

If the spoke is designed with complex geometry to meet appearance requirements, then aesthetic standards are met, but manufacturing complexity increases

Engineering Contradiction:

Improveappearance qualityVSAvoidmanufacturing simplicity

Core Design Contradiction:

ShapeVSEase of manufacture

Solution Approach 1:

The functional projection and the spoke are merged into a single monolithic component manufactured by injection molding. The projection is integrated directly into the spoke structure rather than being a separate attachment, simplifying manufacturing while achieving both functional and aesthetic requirements.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12319334B2Steering wheel

Publication Date: 2025.06.03 DALPHI METAL ESPANA SA

AI summary

The disclosure relates to an improvement of a structure of a steering wheel. For this, the disclosure suggests a steering wheel comprising a monolithic steering wheel base body which includes a central area for mounting the steering wheel to a steering mechanism, a steering wheel rim and at least one spoke whose first spoke end abuts on the central area and whose second spoke end abuts on the steering wheel rim. Accordingly, a projection which restricts tilting of the spoke toward a central area to a predetermined extent is formed in an area of a first spoke end.