Stowable Steering Column Collapse-Limiting Assembly
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Solution Overview
Problem
Existing steering column designs face challenges in managing the retraction of stowable steering columns during impact events, as they absorb energy and require improved retraction management features to prevent excessive collapse.
Innovation Solution
A collapse-limiting assembly for a collapsible steering column utilizing a pyrotechnic element to provide controlled retraction limits, comprising a housing with a moveable member that shifts from a seated to a discharged position upon impact, limiting axial travel between axially adjustable portions, and a processor-controlled system to sense impact events and fire the pyrotechnic charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the steering column is allowed to retract fully into the instrument panel to provide more workspace, then the workspace for parked driver or autonomous driving is improved, but the steering column may collapse excessively during impact events
Solution Approach 1:
The pyrotechnic charge is pre-positioned within the collapse-limiting assembly, ready to fire immediately upon impact detection. This preliminary positioning ensures that the moveable member can be rapidly deployed to the discharged position to limit collapse, resolving the contradiction between allowing full retraction for workspace and preventing excessive collapse during impact events
Solution Approach 2:
The moveable member acts as an intermediary element between the pyrotechnic charge and the axially adjustable portions of the steering column. When fired, the moveable member is propelled into the travel path of the steering column portions, physically limiting their relative axial movement and preventing excessive collapse while allowing normal retraction operations
2Reliability
If a collapse-limiting assembly with pyrotechnic charge is added to the steering column, then collapse control during impact is improved, but the device complexity increases
Solution Approach 1:
The collapse-limiting assembly merges multiple functions into a single integrated unit: the housing contains both the pyrotechnic charge and the moveable member, which combines the actuation mechanism and the collapse-limiting element. This merging reduces overall system complexity compared to having separate systems for impact detection, actuation, and collapse limitation
Solution Approach 2:
The moveable member serves multiple functions: it is both the actuated element (propelled by the pyrotechnic charge) and the collapse-limiting element (physically blocking axial movement). This multi-functionality reduces the number of separate components needed, thereby reducing device complexity while maintaining reliable collapse control
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 effectively locks the steering column at a collapse-limited position, preventing excessive retraction during impacts and enhancing safety by managing energy absorption and maintaining operational stability.
Implementation Method 1
A pyrotechnic charge is located within the housing for firing the moveable member from the seated position to the discharged position during an impact event
Data Source
AI summary
A collapse-limiting assembly for a steering system is provided. The collapse-limiting assembly comprises a housing and a moveable member. A pyrotechnic charge is located in the housing and, in response to an impact event, is caused to fire the moveable member into a discharged position and limit the amount of collapse of a steering column. The steering column includes at least two axially moveable portions that move axially relative to each other between an extended position and a retracted position. When the moveable member is fired into the discharged position, it is located in a travel path of at least one of the axially moveable portions.