Steering Column Load Absorbing Wire Mechanism

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Solution Overview

Problem

Conventional steering column devices experience an abrupt increase in impact absorption load during vehicle collisions due to the fracture of the restricting member, leading to inefficient energy absorption.

Innovation Solution

A steering column device with a tubular outer column and movable inner column, featuring a load-absorbing wire and a restricting member that moves the stopper part radially outward upon load application, preventing contact between the inner column and the stopper and allowing for continued telescopic movement beyond the stopper position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the restricting member is fractured in the middle of contraction of the inner column, then the inner column can move forward beyond the telescopic movement range, but the impact absorption load abruptly increases in the middle of absorption of impact energy

Engineering Contradiction:
Improvetelescopic movement rangeVSAvoidimpact absorption load
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The stopper part is preliminarily positioned to project to the radially inner side of the inner peripheral surface to restrict the front-end position of the inner column during normal operation. When a preset load is applied, the load absorbing wire deforms and moves the stopper part to the radially outer side in advance, allowing the inner column to continue moving forward without abrupt load increase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The load absorbing wire acts as an intermediary mechanism between the inner column and the stopper part. It transmits the load from the inner column to move the stopper part radially outward, enabling smooth transition from restricted to unrestricted movement without abrupt load changes.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the stopper part projects to the radially inner side to restrict the front-end position, then the telescopic position is controlled, but the inner column cannot move beyond the stopper position even under load

Engineering Contradiction:
Improvetelescopic position controlVSAvoidtelescopic movement range
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The stopper part dynamically changes its position based on the applied load. During normal operation, it projects radially inward to control the telescopic position. When a preset load is applied, it moves radially outward through the deformed load absorbing wire, allowing the inner column to extend beyond the original stopper position.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The positional parameter of the stopper part changes from radially inner to radially outer position based on the load condition. This parameter change is achieved through the deformation of the load absorbing wire, which transforms the stopper's function from position restriction to position release under collision conditions.

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 design effectively suppresses the abrupt increase in impact absorption load by allowing the inner column to move beyond the stopper part, enhancing energy absorption and reducing peak loads during collisions.

Implementation Method 1

configured to be deformed by movement of the second end toward a vehicle front side together with the inner column upon application of a load of a preset value or greater to the inner column toward the vehicle front side, to thereby absorb the load

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3225504B1Steering column device
Publication Date: 2019.05.08 FUJI KIKO CO LTD
  • EP3225504B1 patent drawingFigure 1
  • EP3225504B1 patent drawingFigure 2
  • EP3225504B1 patent drawingFigure 3~4

AI summary

A steering column device includes: an outer column having a tubular shape; an inner column movably inserted in the outer column; a restricting member provided through a tubular wall at a lower section of the outer column in such a way as to be capable of coming in and out of the tubular wall in the thickness direction thereof; and a load absorbing wire including first ends engageable with the restricting member and a second end supported on the inner column side, and configured to be deformed by movement of the second end toward the vehicle front side together with the inner column upon application of a load of a preset value or greater to the inner column toward the vehicle front side, to thereby absorb the load.