Steering Column Roll Strap Aperture Collapse Control
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Solution Overview
Problem
Existing energy absorbing roll strap devices for steering column assemblies lack control over kinetic energy dissipation during a crash, as they do not effectively manage the collapse characteristics, leading to unpredictable energy absorption.
Innovation Solution
An energy absorbing device with a curved intermediate portion and an aperture that maintains a constant radius, allowing for controlled deformation and kinetic energy dissipation by shifting the collapse characteristics, facilitating customizable load profiles through aperture design and material removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional roll strap device is used for steering column energy absorption, then the device structure is simple, but the collapse characteristics cannot be controlled and energy dissipation is unpredictable
Solution Approach 1:
The roll strap is segmented into distinct functional zones: a curved portion for initial deformation, a straight portion for controlled collapse, and an aperture that creates a hinge point. This segmentation allows different sections to perform specific functions in the energy absorption sequence, making the collapse characteristics predictable and controllable while maintaining a relatively simple overall structure.
Solution Approach 2:
Different portions of the roll strap are given different geometric properties: the curved portion has a specific radius of curvature to initiate controlled deformation, the straight portion provides a defined collapse path, and the aperture creates a localized hinge point. These local quality variations enable precise control over the collapse sequence and energy dissipation profile without requiring complex external mechanisms.
2Manufacturing precision
If the roll strap collapses without an aperture, then the structure is simpler, but the radius changes during deformation leading to uncontrolled collapse characteristics
Solution Approach 1:
An aperture is extracted from the roll strap material at a specific location in the curved portion. This removal of material creates a hinge point that acts as a pivot during collapse, ensuring the strap deforms along a predictable arc with a constant radius. The aperture is formed through standard manufacturing processes such as punching or drilling, which add minimal complexity while providing precise control over collapse characteristics.
3Adaptability or versatility
If the aperture is positioned differently in the curved portion, then the collapse characteristic control changes, but the manufacturing process becomes more complex
Solution Approach 1:
The position, size, and shape of the aperture are treated as adjustable parameters that can be varied to achieve different collapse characteristics and load profiles. By changing the aperture's location along the curved portion or modifying its dimensions, the energy absorption behavior can be customized for different applications. These parameter changes are implemented through standard manufacturing variations in punching or drilling operations, maintaining ease of manufacture while providing adaptability.
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 enables precise control over the energy absorption process, allowing for tailored kinetic energy dissipation profiles, enhancing safety by ensuring consistent and controlled energy absorption during vehicle collisions.
Implementation Method 1
The intermediate portion includes a curved portion having a radius, and an aperture extending through the intermediate portion. The aperture is configured to shift a collapse characteristic of the energy absorbing device and to facilitate maintaining the radius constant when a force moves the first end relative to the second end and deforms the energy absorbing device.
Data Source
AI summary
In an exemplary embodiment of the invention, an energy absorbing device for a steering column assembly is provided. The device includes a first end configured to couple to a first component of the steering column assembly, a second end configured to couple to a second component of the steering column, and an intermediate portion extending between the first and second ends. The intermediate portion includes a curved portion having a radius, and an aperture extending through the intermediate portion. The aperture is configured to shift a collapse characteristic of the energy absorbing device and to facilitate maintaining the radius constant when a force moves the first end relative to the second end and deforms the energy absorbing device.