Steering Device Single Fixing Member Impact Absorption

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Solution Overview

Problem

Conventional steering devices face challenges in achieving a simple structure with appropriate impact absorption and high rigidity, often requiring complex coupling structures and increased fastening parts, which restricts rigidity and increases costs.

Innovation Solution

A steering device with a single fixing member integrating a drive member, a first impact absorption member, and an action member, where the action member plastically deforms the impact absorption member upon a predetermined load, allowing for efficient impact absorption without relying on bending strength, and optionally incorporating a second impact absorption member for enhanced energy absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the energy absorption member is used as a drive force transmission member with both end portions coupled to the movable member and the support member, then the impact absorption function is achieved, but the structure becomes complicated and the number of fastening parts increases

Engineering Contradiction:
Improveimpact absorption functionVSAvoidcoupling structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the energy absorption member with either the support member or the movable member into a single integrated component. This eliminates the need for separate coupling structures and fastening parts between these components, thereby simplifying the overall structure while maintaining the impact absorption function through the deformation portion of the integrated member.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated member serves multiple functions simultaneously: it provides structural support, transmits drive force, and absorbs impact energy through its deformation portion. This multi-functionality reduces the number of separate components needed in the steering device.

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

2Ease of operation

If the energy absorption member is designed with sufficient rigidity to transmit drive force and oppose frictional force, then the expansion-contraction adjustment is enabled, but the rigidity setting is restricted and a lower limit value occurs in load setting

Engineering Contradiction:
Improveexpansion-contraction adjustmentVSAvoidrigidity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The integrated member is segmented into different functional regions: a rigid portion for transmitting drive force and opposing friction, and a deformation portion for plastic deformation during impact. This segmentation allows different parts of the same member to have different rigidity characteristics, enabling both smooth adjustment operation and adequate impact absorption.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the integrated member are designed with different mechanical properties. The portion responsible for drive force transmission is designed with high rigidity, while the deformation portion is designed with lower strength to facilitate plastic deformation during impact, allowing localized optimization of mechanical properties.

Inventive Principle:
Principle #3Local quality

3Strength

If the energy absorption member is designed with high rigidity to prevent bending and deformation during normal operation, then the sense of steering rigidity is improved, but the impact absorption capability is reduced

Engineering Contradiction:
Improvesteering rigidityVSAvoidimpact absorption capability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The member is divided into a rigid portion that maintains steering rigidity during normal operation and a deformation portion that undergoes plastic deformation during impact. This segmentation allows the steering system to exhibit high rigidity during normal use while still providing effective impact absorption when needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The member transitions from a static rigid structure to a dynamic system where the deformation portion can change its mechanical properties under different load conditions. During normal operation, the member appears rigid, but during impact, the deformation portion becomes more compliant through plastic deformation, enabling adaptive response to different operating conditions.

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 provides a compact, cost-effective steering device with improved rigidity and impact absorption characteristics, reducing the number of fixing members and simplifying assembly, while enhancing safety by distributing the impact force effectively.

Implementation Method 1

a deformation portion (32) that extends from the main body portion (31) in a direction along the axis X and is bent in such a way as to be parallel to the main body portion (31)

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP4067209B1Steering device
Publication Date: 2023.08.30 AISIN CORP
  • EP4067209B1 patent drawingFigure 1~2
  • EP4067209B1 patent drawingFigure 3A~3C
  • EP4067209B1 patent drawingFigure 4~5

AI summary

A steering device includes: an inner tube (1) including a steering wheel; a column housing that houses the tube (1) retractably along an axis (X); a drive mechanism (K) attached to the column housing so as to cause the tube (1) to perform a retraction operation via a drive member (4, 5) reciprocating along the axis (X); a first impact absorption member (3) that is provided on one of the drive member (4, 5) and the tube (1), and includes a deformation portion (32); and an action member (7) that is provided on another, and plastically deforms the deformation portion (32). The drive member (4, 5), the first impact absorption member (3), and the action member (7) are fixed by a single fixing member (6). When a predetermined pushing load acts on the tube (1), fixing between the first impact absorption member (3) and the action member (7) is released.