Axle Actuator Coupler for Spring Rate Adjustment

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Solution Overview

Problem

Existing axle actuators for motor vehicle wheel suspensions lack a simple and reliable method to adjust the total spring rate, leading to inefficiencies in torsional stress and weight distribution.

Innovation Solution

The axle actuator incorporates a coupler with a defined spring rate, connected via joints to both the output lever and wheel guide element, which is configured as a flexible spring, allowing the torsion bar spring to be used with a smaller diameter and lower weight, and optionally as a nested torsion spring system, enabling adjustment of the total spring rate without altering geometric dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the output lever is directly linked to the wheel guide element, then the connection is rigid and structurally simple, but the spring rate cannot be adjusted and torsional stress is high

Engineering Contradiction:

Improvetorsional stressVSAvoidconnection structure

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

A coupler is introduced as an intermediary component between the output lever and the wheel guide element. This coupler acts as a mediator that transmits forces while providing spring characteristics, thereby reducing torsional stress on the torsion bar spring without requiring a complete redesign of the connection structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The coupler is designed with specific spring characteristics (spring rate) that can be adjusted by changing its geometric parameters such as thickness, length, and material properties. This allows the spring rate of the suspension system to be modified without changing the overall structure, enabling optimization of torsional stress while maintaining structural integrity.

Inventive Principle:

Principle #35Parameter changes

2Weight of moving object

If a torsion bar spring with smaller diameter is used to reduce weight, then the weight is reduced, but the spring rate adjustment becomes difficult

Engineering Contradiction:

Improvetorsion bar spring weightVSAvoidspring rate adjustment

Core Design Contradiction:

Weight of moving objectVSAdaptability or versatility

Solution Approach 1:

The suspension system is segmented into distinct functional components: the torsion bar spring for weight reduction and the coupler for spring rate adjustment. This segmentation allows each component to be optimized independently - the torsion bar can be made lighter while the coupler's geometric parameters are adjusted to achieve the desired spring rate.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The spring rate is adjusted by changing the geometric parameters of the coupler (thickness, length, material properties) rather than changing the torsion bar spring dimensions. This enables spring rate customization while maintaining the advantage of using a lighter, smaller-diameter torsion bar spring.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If the coupler is made as a rigid connection, then the structure is simpler, but the spring rate cannot be lowered and torsional stress remains high

Engineering Contradiction:

Improvecoupler structureVSAvoidtorsional stress

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The coupler is designed as a flexible component with spring characteristics, utilizing thin-walled structures that can deform elastically under load. This flexible design allows the coupler to absorb and distribute torsional stresses while maintaining structural integrity, avoiding the need for complex rigid mechanisms.

Inventive Principle:

Principle #30Flexible shells and thin films

4Adaptability or versatility

If the total spring rate is reduced for smaller vehicle models, then the suspension is softer and more suitable, but the geometric dimensions must be changed

Engineering Contradiction:

Improvespring rate for different vehicle modelsVSAvoidtorsion spring system length

Core Design Contradiction:

Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The spring rate is adjusted by changing the coupler's geometric parameters (thickness, length, material properties) rather than changing the overall length or geometric dimensions of the torsion spring system. This allows customization for different vehicle models while maintaining the same compact geometric footprint.

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 configuration reduces torsional stress on the torsion bar spring, allows for the use of lighter components, and enables the axle actuator to be installed in smaller vehicles by lowering the total spring rate, while maintaining geometric integrity and optimizing weight distribution.

Implementation Method 1

the coupler being configured as a spring with defined spring rate

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a torsion bar spring acting on a wheel side upon the output lever

Methodology Applied

Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentUS8851493B2Suspension system for a wheel suspension of a motor vehicle

Publication Date: 2014.10.07 AUDI AG

AI summary

An axle actuator for a wheel suspension of a motor vehicle includes an output lever, a torsion bar spring acting on a wheel side upon the output lever, and a rotary actuator adapted to adjust a tension of the torsion bar spring. A coupler links the output lever to a wheel guide element of the wheel suspension and is configured as a spring with defined spring rate and connected by joints with the output lever and the wheel guide element.