Asymmetric Steering Column Mounting for Impact Absorption

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Solution Overview

Problem

In impact absorbing steering apparatuses, the displacement of the steering column in the forward direction during a secondary collision is not always smooth due to the presence of an electric motor protruding from the housing of the electric power steering apparatus.

Innovation Solution

The impact absorbing steering apparatus features a steering column with installation plate sections that have different distances from the center axis to the connecting sections with the vehicle body, allowing for differential impact loads and incorporating energy absorbing members that deform plastically to facilitate smooth forward displacement, even when the electric motor protrudes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If an electric motor protrudes from the housing of the electric power steering apparatus, then the power steering function is provided, but the displacement of the steering column in the forward direction during collision becomes uneven and non-smooth

Engineering Contradiction:
Improvepower steering functionVSAvoidsmoothness of steering column displacement
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies asymmetry by making the installation plate sections asymmetric in their connection to the vehicle body. Specifically, the left and right installation plate sections have different distances from the center axis of the steering column to their connecting sections with the vehicle body. This asymmetric configuration compensates for the asymmetric position of the electric motor, allowing both sides to experience balanced impact loads during collision and enabling smooth forward displacement of the steering column.

Inventive Principle:
Principle #4Asymmetry

2Object-affected harmful factors

If the steering column is designed to displace in the forward direction to absorb impact energy, then driver protection is improved, but the presence of the electric motor creates uneven loading that prevents smooth displacement

Engineering Contradiction:
Improveimpact energy absorptionVSAvoidsmoothness of displacement
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent uses asymmetric installation plate section design where the distances from the steering column center axis to the connecting sections differ between left and right sides. This asymmetry is specifically configured to counterbalance the asymmetric position of the electric motor, ensuring that during forward displacement for impact energy absorption, the impact loads are evenly distributed and the displacement remains smooth.

Inventive Principle:
Principle #4Asymmetry

3Device complexity

If the installation plate sections are positioned symmetrically, then the structure is simple, but the electric motor causes uneven impact load distribution during collision

Engineering Contradiction:
Improvestructural simplicityVSAvoidimpact load distribution
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The patent deliberately introduces asymmetry in the installation plate section configuration to counterbalance the asymmetric electric motor position. The left and right installation plate sections have different distances from the steering column center axis, creating an asymmetric structure that achieves symmetric impact load distribution during collision, thus resolving the force imbalance caused by the motor's position.

Inventive Principle:
Principle #4Asymmetry

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 enables the steering wheel to displace smoothly in the forward direction during a secondary collision, effectively absorbing impact energy and protecting the driver by optimizing the displacement of the steering column and energy absorption mechanisms.

Implementation Method 1

providing an energy absorbing member, which absorbs an impact load by deforming plastically, between a portion that displaces in the forward direction together with the steering column 6 and the vehicle body

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP2447132B1Energy-absorbing steering device
Publication Date: 2015.11.11 NSK LTD
  • EP2447132B1 patent drawingFigure 1
  • EP2447132B1 patent drawingFigure 2
  • EP2447132B1 patent drawingFigure 3(A)~3(B)

AI summary

Construction is achieved wherein a steering wheel can displace smoothly in the forward direction during a secondary collision, even when an electric motor 13a of an electric power steering apparatus protrudes to the side. The distances from the center axis of the steering column 6c to the connecting sections between the installation plate sections 17e, 17f and a portion 34 fastened to the vehicle body are different from each other on both sides of the steering column 6c, such that the distance Le for the installation plate section 17e located on the side where the electric motor 13a is located is shorter than the distance Lf for the installation plate section 17f that is located on the opposite side from the electric motor 13a. The ratio of a separation load that is applied to the installation plate section 17e on the side where the electric motor 13a is located is made to be large. The tendency for the dropping away toward the front on the side where the electric motor 13, having a large inertial mass, is located, being difficult, is cancelled out by the ease of the dropping away of the installation plate section 17e.