Rear Wheel Steering Mechanism with Magnetic Blocking

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Solution Overview

Problem

Existing rear wheel steering devices require significant design effort and can experience unwanted wheel steering movements if the drive unit fails, necessitating a solution to prevent such movements without modifying the wheel suspension.

Innovation Solution

A steering device with a blocking mechanism using a magnetic tappet and a length-adjustable wheel guide member, integrated into a conventional wheel suspension, which includes an electromechanical drive unit and a freewheel device to ensure symmetrical motor operation and prevent unwanted length changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional steering device with tie rod and wheel control arm is used, then the wheel lock angle can be adjusted, but the design effort and complexity increase significantly

Engineering Contradiction:
Improvewheel lock angle adjustmentVSAvoiddesign effort
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The wheel guide member is segmented into a fixed part and an adjustable part connected by a ball joint, allowing independent adjustment of the wheel lock angle while maintaining the integrity of the overall suspension structure. This segmentation enables modular replacement of only the necessary component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The length-adjustable wheel guide member serves multiple functions: it maintains the primary wheel suspension function while simultaneously providing adjustable wheel lock angle control. This multi-functionality eliminates the need for separate steering mechanisms, reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If the drive unit of the steering device fails, then the wheel guide member length changes uncontrollably, but unwanted wheel steering movements occur

Engineering Contradiction:
Improvelength adjustmentVSAvoidunwanted steering movement prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The ball joint connection is designed to allow free length adjustment during normal operation but automatically locks in fixed positions when the drive unit fails or is switched off. This preliminary design ensures that unwanted steering movements are prevented without requiring additional active blocking mechanisms.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The ball joint connection provides self-blocking functionality when the drive unit is inactive, using its own mechanical structure to prevent unwanted movements. The connection allows controlled adjustment during operation but automatically restricts movement when power is removed, making the system self-regulating.

Inventive Principle:
Principle #25Self-service

3Reliability

If a hydraulic actuator with piston rod and lever is used, then the wheel pivoting can be controlled, but the wheel suspension must be modified

Engineering Contradiction:
Improvewheel pivoting controlVSAvoidwheel suspension modification
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The wheel guide member is designed to perform both its traditional suspension function and the additional function of wheel lock angle adjustment through integrated length adjustment. This eliminates the need for separate steering linkages and modifications to the wheel suspension structure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The wheel guide member transitions from a fixed-length component to a dynamically adjustable component, allowing the wheel lock angle to be varied as needed. This dynamic adjustment capability is achieved through the ball joint connection that permits controlled length changes while maintaining structural integrity.

Inventive Principle:
Principle #15Dynamics

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 solution prevents unwanted wheel steering movements by blocking the drive unit when it fails, allowing for easy integration into conventional suspensions and maintaining efficient motor operation, thus enhancing the stability and design simplicity of rear wheel steering systems.

Implementation Method 1

at least one magnetic tappet (101) can be positively inserted into a receptacle (100) of a nut (68) or a coupling element (67) by switching off an electromagnet (102), whereby the drive unit (53) can be blocked

Methodology Applied
Scientific EffectElectromagnet: Electromagnet

Data Source

PatentEP1879781B1Steering mechanism, especially for a rear wheel steering mechanism
Publication Date: 2010.12.29 CONTINENTAL TEVES AG & CO OHG
  • EP1879781B1 patent drawingFigure 1~2
  • EP1879781B1 patent drawingFigure 3
  • EP1879781B1 patent drawingFigure 4

AI summary

The aim of the invention is to integrate a steering device for adjusting a steer angle of a motor vehicle wheel, particularly a rear wheel, into a conventional wheel suspension. Said aim is achieved by a steering device comprising at least one wheel guiding member via which a wheel support is connected to a vehicle body. The wheel support is pivotable about an axis of rotation that extends substantially parallel to the wheel plane while the wheel guiding member is hingedly connected to wheel support at a distance from the axis of rotation. The length of the wheel guiding member is adjustable by means of a drive unit.