Steering and Suspension System with Strut Extension Member

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Solution Overview

Problem

Conventional McPherson strut suspension systems result in a large spindle length, leading to increased steering system loads and traction steer concerns, particularly in high-powered front wheel drive vehicles, and existing modifications are costly, complex, or compromise durability.

Innovation Solution

A steering and suspension system with a strut extension member, compliant hinge joint, and adjustable components that reduce spindle length, allowing for improved alignment and independent tuning of steer axis, camber, and lateral force generation without requiring substantial changes to the vehicle frame or body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional McPherson strut suspension is used, then the vehicle frame or body can be designed specifically for this suspension type, but the spindle length becomes larger than desirable, increasing steering system loads

Engineering Contradiction:

Improvevehicle frame design compatibilityVSAvoidspindle length

Core Design Contradiction:

Ease of manufactureVSLength of moving object

Solution Approach 1:

The suspension system is divided into separate functional components: a strut assembly, a steering knuckle, and an extension member that connects them. This segmentation allows the steer axis to be repositioned closer to the wheel center plane by extending the connection path, thereby reducing spindle length while maintaining compatibility with existing vehicle frames designed for conventional McPherson strut suspensions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An extension member acts as an intermediary component between the strut assembly and the steering knuckle. This extension member includes a steer axis that is positioned closer to the wheel center plane than in conventional designs, allowing the spindle length to be reduced without requiring substantial changes to the vehicle frame or body structure

Inventive Principle:

Principle #24Intermediary (Mediator)

2Force

If the steer axis is repositioned closer to the wheel center plane to reduce spindle length, then steering system loads are reduced, but the design becomes more complicated and costly

Engineering Contradiction:

Improvesteering system loadsVSAvoidsuspension system design complexity

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The extension member serves multiple functions: it extends the connection between the strut and steering knuckle, defines a new steer axis position, and provides mounting points for the control arm. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in design complexity despite achieving reduced spindle length and steering system loads

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Length of moving object

If a different suspension type is used to reduce spindle length, then steering performance is improved, but substantial changes to the vehicle frame or body are required

Engineering Contradiction:

Improvespindle lengthVSAvoidvehicle frame modification requirements

Core Design Contradiction:

Length of moving objectVSEase of manufacture

Solution Approach 1:

The extension member incorporates adjustable elements including a adjustable control arm with variable length and mounting positions. This adjustability allows the system to be tuned for optimal performance while maintaining compatibility with existing vehicle frames, achieving reduced spindle length without requiring substantial frame or body modifications

Inventive Principle:

Principle #15Dynamics

4Adaptability or versatility

If adjustable components are added to allow independent tuning of steer axis and camber, then suspension performance is improved, but the system becomes more complex and costly

Engineering Contradiction:

Improvesuspension tuning capabilityVSAvoidadjustable components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The extension member combines multiple adjustment capabilities into a single integrated component. The control arm can be adjusted in length and mounting position, and the extension member itself can be positioned at different locations, all while maintaining a compact structure. This merging of adjustment functions into unified components achieves high adaptability while limiting the increase in overall system complexity and cost

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS7490840B2Steering and suspension system for a vehicle

Publication Date: 2009.02.17 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

The present invention concerns a steering and suspension system of a vehicle. The system may include a strut extension member having a strut clamp arm mounted to a strut assembly, an upper extension support arm extending from the strut clamp arm, an extension fork with first and second arms extending from the strut clamp arm, and a lower extension support arm extending from the extension fork. Also, a steering knuckle has an upper portion pivotally coupled to the upper extension support arm, and a lower portion pivotally coupled to the lower extension support arm. A lower control arm has an outboard portion with a control arm mounting bore therethrough, and a compliant hinge joint includes a first joint associated with the first arm, a second joint associated with the second arm, and a shaft extending through the first joint, the second joint and the mounting bore.