Collapsible Steering Column Variable Energy Absorption
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Solution Overview
Problem
Current energy absorbing steering columns have fixed energy absorption capabilities, failing to adjust for varying driver sizes and collision severities, and do not deploy adjustments quickly enough to effectively protect all drivers during collisions.
Innovation Solution
A collapsible steering column assembly with a telescopically retracting structure and a variable energy absorbing device using a plastically-deformable strap with pyrotechnic fuses, allowing for adjustable resistance stages based on driver characteristics and collision conditions, enabling dynamic energy absorption matching different load curves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed energy absorbing device is used, then the structure is simple, but it cannot adapt to different driver sizes and collision severities
Solution Approach 1:
The energy absorbing device is divided into multiple stages with different energy absorption characteristics. The strap structure is segmented into different deformation stages, and pyrotechnic fuses are used to selectively activate specific stages based on collision severity and driver characteristics, enabling adaptability without requiring completely different devices for each scenario.
Solution Approach 2:
The energy absorbing device transitions from a static, fixed-characteristic system to a dynamic, adjustable system. The pyrotechnic fuses enable the device to change its energy absorption characteristics in real-time based on sensed conditions, allowing the same physical structure to provide optimized protection for different driver sizes and collision types.
2Speed
If a traditional energy absorbing device is used, then the manufacturing is simple, but it cannot adjust performance quickly enough to match airbag deployment timing
Solution Approach 1:
The patent replaces traditional mechanical adjustment mechanisms with pyrotechnic fuses that can activate energy absorption stages in milliseconds. This substitution of activation method enables speed comparable to airbag deployment while maintaining structural simplicity, as the fuses provide rapid, clean activation without complex mechanical linkages or electronic control systems.
3Adaptability or versatility
If a fixed load curve is used, then the energy absorption is consistent, but it cannot optimize protection for different driver groups
Solution Approach 1:
Different stages of the energy absorbing strap are designed with locally optimized properties for different driver groups. Each stage has specific deformation characteristics tailored to protect particular driver sizes or collision types, allowing the system to provide optimized protection for small drivers, large drivers, or various collision scenarios by activating the appropriate stage.
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 adjustable energy absorption to better protect drivers of different sizes and in varying collision conditions, mimicking the rapid deployment of airbags by varying resistance stages within milliseconds, ensuring effective kinetic energy dissipation during collisions.
Implementation Method 1
A collapsible steering column assembly may include an energy absorbing (E/A) device having a member, such as a strap, engaged between the inner and outer tubes... The distal end is disengagably attached to the outer tube via a pin received in a hole in the distal end and a fuse engaged operably to the pin and attached to the outer tube
Implementation Method 2
The E/A device preferably exerts a variable resistance along collapse stroke of the column. In one embodiment of the present invention, the E/A device variably accommodates: low load stage for use with, e.g., a smaller driver, lower speed of vehicle, and/or the driver being belted; the high load stage is preferably for use with, e.g., a heavier driver, high speed of vehicle, and/or the driver being unbelted driver
Data Source
AI summary
A collapsible steering column assembly preferably has a collapsible steering shaft that extends rotatably along a centerline and a collapsible column that houses and co-extends with the shaft. The column preferably has inner and outer jackets that retract axially to collapse the column. An energy absorbing device has a member engaged between the inner and outer jackets and controls the collapse of the column generally via a high load stage and a low load stage of operation. The member is preferably elongated axially having a distal end that is looped over and spaced radially outward from the remainder of the member. The distal end is attached disengagably to the outer jacket via a pin received in a hole in the distal end and a fuse engaged operably to the pin and attached to the outer jacket.