Countersteering Rear Axle Support for Toe-In Control

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Solution Overview

Problem

Existing vehicle rear axles, particularly those of torsion-beam design, tend to oversteer under lateral forces due to insufficient strength and complexity in existing countersteering mechanisms, such as those with four elastic pivot bearings or simple plate-shaped spring elements.

Innovation Solution

A countersteering rear axle design featuring a support part with flexible sections connected via an edge forming the virtual expansion axis, supported by a U-shaped plate attached to the axle body, providing sufficient rigidity and strength while allowing pivoting of the wheel carrier to achieve toe-in under lateral forces, with optional reinforcement plates and a soft connecting element for enhanced flexibility and damping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a plate-shaped spring element is used to carry the wheel carrier, then the device complexity is reduced, but the operational strength becomes insufficient

Engineering Contradiction:
Improvestructure complexityVSAvoidoperational strength
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The support part is divided into multiple sections (first section essentially parallel to the wheel carrier plane, second section extending in transverse direction, third web section) connected via edges forming the expansion axis. This segmentation allows each section to perform specific functions while maintaining overall structural integrity and sufficient strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support part combines flexible sections with reinforcement plates and integrates with the U-shaped support plate and axle body to create a composite structure. This composite design provides both the necessary flexibility for countersteering and the operational strength required for vehicle axles.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If four elastic pivot bearings are integrated into a pendulum plate, then the wheel steers into toe-in under lateral forces, but the device complexity increases significantly

Engineering Contradiction:
Improvecountersteering functionVSAvoidstructure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention extracts the essential countersteering function from the complex four-pivot-bearing pendulum plate design and implements it through a simplified support part with flexible sections and a U-shaped support plate. The support part pivots about the virtual expansion axis to achieve toe-in without requiring multiple elastic pivot bearings.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the structural parameters from rigid pivot bearings to flexible sheet metal sections with controlled flexibility. The flexibility of the support part sections and the U-shaped support plate provides the necessary pivoting capability while simplifying the overall structure.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the support part has flexible sections connected via an edge forming the expansion axis, then the wheel carrier can pivot to achieve toe-in, but the structural rigidity must be maintained

Engineering Contradiction:
Improvepivoting capabilityVSAvoidstructural rigidity
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The support part has different local qualities: flexible sections for pivoting about the expansion axis, and reinforced areas with reinforcement plates for maintaining structural rigidity. The web section connects these areas, providing both flexibility where needed and rigidity where required for precise wheel guidance.

Inventive Principle:
Principle #3Local quality

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

The design achieves precise wheel guidance and desired toe-in behavior under lateral forces, meeting operational strength requirements with a simpler and more cost-effective structure compared to complex prior art solutions, while also improving braking and longitudinal force handling.

Implementation Method 1

the support part has a section which is essentially parallel to the plane of the wheel carrier and is flexible to a certain extent, as well as a section which follows behind the center point of the wheel when viewed in the direction of travel and extends essentially in the transverse direction of the vehicle having a certain flexibility

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2291293B1Countersteering automotive rear axle
Publication Date: 2015.08.19 BAYERISCHE MOTOREN WERKE AG
  • EP2291293B1 patent drawingFigure 1~2
  • EP2291293B1 patent drawingFigure 3
  • EP2291293B1 patent drawingFigure 4

AI summary

The invention relates to a countersteering automotive rear axle, inducing a rotational motion of a wheel carrier about a virtual axis of spread in the direction of positive toe-in under the effect of a side force on the wheel on the outside of a curve and mounted on said wheel carrier, wherein the support comprises a segment substantially parallel to the plane of the wheel carrier and a segment extending substantially in the transverse vehicle direction and abutting said segment behind the wheel center point in the direction of travel, said segment being tilted in a side projection substantially identically to the virtual spread axis relative to the vertical direction, and that said carrier is supported at least at the free ends of an approximately U-shaped sheet metal support in a side projection, said support in turn being mounted on the axle body. A sheet metal reinforcement is preferably provided above and/or below the wheel center point, by means of which the support and the sheet metal support are supported on the axle body.