Steering Column Energy Absorption Through Plastic Deformation
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Solution Overview
Problem
Existing steering column assemblies with energy absorption devices face challenges in achieving a compact design with excellent energy absorption behavior, particularly in minimizing driver injury during vehicle crashes, especially in scenarios without seat belts.
Innovation Solution
A steering column assembly with a vehicle-fixed mounting element and a sleeve element, featuring an energy absorption device with an elongate absorption part and a reduction part, where the absorption part is plastically deformed through a passage with a smaller cross-section, allowing for efficient energy absorption by relative longitudinal movement, and optionally adjustable to different energy absorption levels through a coupling device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional energy absorption devices with bent or torn deformation elements are used, then energy absorption capability is achieved, but device complexity and size increase
Solution Approach 1:
The absorption part is divided into distinct functional zones: a first portion with constant cross-section for elastic deformation, and a second portion with varying cross-section for progressive plastic deformation. This segmentation allows different deformation mechanisms to occur in controlled sequences, achieving reliable energy absorption while maintaining structural simplicity.
Solution Approach 2:
The cross-sectional area of the absorption part varies locally along its length, with the second portion having a smaller cross-section than the first portion. This local quality variation creates predetermined deformation zones that absorb energy through controlled plastic deformation, simplifying the overall device structure while ensuring reliable energy absorption performance.
2Volume of moving object
If absorption part cross-section is reduced for compact design, then device compactness improves, but energy absorption capacity may be compromised
Solution Approach 1:
The absorption part is designed to undergo dynamic deformation during impact, transitioning from elastic deformation in the first portion to plastic deformation in the second portion. This dynamic response allows the device to adapt its energy absorption characteristics to the impact force, maintaining high energy absorption capacity in a compact form factor.
Solution Approach 2:
The cross-sectional parameters of the absorption part are strategically varied along its length, with the second portion having a reduced cross-section compared to the first portion. This parameter change creates a progressive deformation mechanism that maximizes energy absorption within limited space, resolving the contradiction between compactness and energy absorption capacity.
3Reliability
If the absorption part is designed with varying cross-section for better energy absorption, then energy absorption behavior improves, but manufacturing complexity increases
Solution Approach 1:
The absorption part is pre-formed during manufacturing with the desired varying cross-sectional profile, creating predetermined deformation zones before the component is installed. This preliminary action ensures that the component will deform in a controlled manner during impact, achieving reliable energy absorption behavior while using standard manufacturing processes for extruded or formed metal components.
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 and effective energy absorption mechanism that adapts to various crash situations, ensuring efficient energy dissipation and minimizing driver injury, while being compatible with both standard and inverted tube-in-tube concepts.
Implementation Method 1
the end portion is plastically deformed in cross-section through the smaller passage in cross-section
Data Source
AI summary
A steering column assembly for a vehicle, in particular a motor vehicle, provides that an absorption part extends into a reduction part through a passage, which has a smaller cross-section than an end portion of the absorption part having the form of a rod, tube or wire. By a relative movement between the reduction part and the absorption part the end portion is pulled through the passage and plastically deformed. In such a way, an energy absorption device is formed.