Steering Column Energy Absorber Guide Plate Design

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Solution Overview

Problem

Existing impact absorbing steering apparatuses face instability in energy absorption performance due to moments applied during secondary collisions, leading to unstable friction fits and limited design freedom, with increased costs associated with specialized components.

Innovation Solution

The impact absorbing steering apparatus features a steering column with an inner and outer column design, including a slit for diameter expansion or contraction, a tightening rod with pressure sections, and an energy absorbing member that plastically deforms to absorb impact energy, with the energy absorbing member strategically placed between displacing and non-displacing components to reduce moments and enhance stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an energy absorbing member is provided between the vehicle body and steering column to absorb impact load during secondary collision, then impact energy absorption is improved, but moments are applied during collision causing unstable friction fit and sliding movement

Engineering Contradiction:
Improveimpact energy absorptionVSAvoidfriction fit stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

A guide plate is introduced as an intermediary component between the energy absorbing member and the steering column. The guide plate includes a guide section that guides the sliding movement of the outer column, ensuring stable and controlled motion during impact absorption while preventing unstable friction fit and sliding movement

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If specialized components are added to improve impact absorption performance, then energy absorption capability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveenergy absorption capabilityVSAvoidcomponent complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The guide plate serves multiple functions: it guides the sliding movement of the outer column, supports the energy absorbing member, and stabilizes the friction fit. By combining multiple functions into a single component, the overall device complexity is reduced while maintaining improved energy absorption capability

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

Solution Approach 2:

The guide section of the guide plate changes the movement parameters of the outer column by providing a controlled sliding path. This parameter change ensures stable and predictable motion during impact absorption without requiring complex additional components

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 stabilizes the friction fit and sliding movement between column components, improves impact energy absorption, and maintains design freedom while reducing costs by utilizing existing components.

Implementation Method 1

an energy absorbing member that is located between a portion that displaces in the forward direction together with the outer column during the secondary collision and a portion that does not displace in the forward direction during the secondary collision, and that absorbs part of the impact energy through the relative movement

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

stabilizes the friction fit and sliding movement between column components

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2439126B1Shock-absorbing steering device
Publication Date: 2015.08.12 NSK LTD
  • EP2439126B1 patent drawingFigure 1
  • EP2439126B1 patent drawingFigure 2
  • EP2439126B1 patent drawingFigure 3

AI summary

Construction of an impact absorbing steering wheel apparatus that is capable of obtaining excellent performance at low cost while maintaining the freedom of design is achieved. An energy absorbing member comprises: a base plate section 55, 71: an energy absorbing section 53, 73 that is located in the rear half section of the base plate section, or extends toward the rear from the base plate section and has a bent back section 57, 73 that is bent back in a U shape upward or downward with respect to the base plate section; a rear end installation section 58, 74 that is located on the tip end section of the bent back section; and a front end installation section 54, 76 that is located in front of the base plate section; wherein the tip end section of the bent back section 57, 73 and the rear end installation section 58, 74 are located in a space between a pair of held wall sections 11a and fastened to a tightening rod 27a; the front end installation section 54, 76 is fastened to the front end section of an inner column 14a or the housing 16 of a electric-powered steering apparatus. Near the energy absorbing section 53, 73, there is a guide section that, when the bent back section 57, 73 moves as the rear end installation section 58, 74 moves in the forward direction together with an outer column 13a during a secondary collision, guides the movement of the bent back section 57, 73.