Steering Column Energy Absorbing Laminated Strap
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Solution Overview
Problem
Steering column assemblies in vehicles require adjustable reach and controlled collapse during crashes, but existing energy absorbing devices can complicate reach adjustment and are not easily adaptable to varying crash forces.
Innovation Solution
A laminated energy absorbing strap with discrete layers, coiled into a spiral, is used between support brackets to absorb energy and control collapse, allowing for adjustable thickness and energy absorption characteristics, reducing the number of fasteners needed and facilitating easy interchange of straps with different properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional energy absorbing device is used in a collapsible steering column assembly, then crash protection is provided, but the device complexity increases and reach adjustment becomes more difficult
Solution Approach 1:
The energy absorbing device is segmented into a laminated structure comprising multiple discrete strips (first strip, second strip, and additional strips) that can slide relative to each other. This segmentation allows the device to absorb energy through inter-layer friction and deformation while maintaining a compact, integrated form factor that does not complicate the overall steering column assembly or reach adjustment mechanisms.
Solution Approach 2:
The energy absorption characteristics are adjusted by changing parameters such as the number of strips, their dimensions, material properties, and coil geometry. This allows customization of crash protection levels without fundamentally changing the device structure, thereby avoiding increased complexity while maintaining reliability.
2Ease of manufacture
If a fixed thickness energy absorbing strap is used, then manufacturing is simplified, but adaptability to varying crash forces is reduced
Solution Approach 1:
The strap is divided into multiple discrete strips of the same thickness that can be configured in different quantities and arrangements. This segmentation allows the energy absorption capacity to be adapted to varying crash forces by adjusting the number and configuration of strips, while each individual strip maintains a simple, uniform thickness that is easy to manufacture.
Solution Approach 2:
The energy absorbing device uses a composite structure of multiple strips layered together, where each strip is simple to manufacture but the combined structure provides adaptable energy absorption. The composite nature allows tuning of crash protection by adding or removing strips without complicating the manufacturing of individual components.
3Strength
If multiple fasteners are used to secure the energy absorbing device, then connection strength is improved, but assembly complexity and cost increase
Solution Approach 1:
Multiple fastening functions are merged into a single integrated fastener that secures the laminated strip assembly to the support bracket. This single fastener design maintains connection strength by distributing loads across the laminated structure while significantly reducing assembly complexity and the number of fastening operations required.
Solution Approach 2:
The fastener design serves multiple functions simultaneously: it secures the laminated strips to the bracket, allows for reach adjustment movement, and maintains connection strength during crash events. This multi-functionality reduces the need for multiple specialized fasteners, thereby simplifying assembly while maintaining strength.
4Stability of the object's composition
If a non-adjustable energy absorbing device is used, then structural integrity is maintained, but reach adjustment capability is lost
Solution Approach 1:
The energy absorbing device is designed with dynamic characteristics that allow it to remain structurally intact during normal reach adjustment operations while absorbing energy during crash events. The laminated strip structure with sliding interfaces provides controlled movement during adjustment but maintains structural integrity when subjected to crash forces.
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 laminated strap effectively controls the collapse of the steering column assembly while allowing for easy reach adjustment and customizable energy absorption, reducing the complexity and cost of assembly and improving crash resistance.
Implementation Method 1
an energy absorbing device that acts between the first and the second support bracket and which in the event of a collapse of the steering column assembly deforms so as to absorb energy and thereby at least partially controlling the collapse of the steering column assembly
Implementation Method 2
each layer formed from a separate elongate strip of material that is free to slide over the other strip along a major portion of its length
Data Source
AI summary
A steering column assembly comprises a first support bracket, a second support bracket, a shroud, and an energy absorbing device. The energy absorbing device comprises a laminated strap having discrete first and second layers, each formed from a separate elongate strip of material that is free to slide over the other strip along a major portion of its length, a portion of the laminated strap being coiled into a spiral, a free end portion of the laminated strap passing through passing through an opening in the second support bracket or the shroud, the free end of a first one of the strips having an opening through which a fastener passes that secures the laminated strap to the first support bracket, and the free end of a second one of the straps being connected to the first strip in a region distal from the free end of the first strip.