Steering Column Shroud Segmentation for Reach Adjustment
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Solution Overview
Problem
Steering column assemblies with limited reach adjustment capability when in the full reach position, and the need for enhanced structural strength and controlled collapse mechanisms in the event of a crash.
Innovation Solution
A steering column assembly with a two-part shroud system featuring elongate slots on both the inner and outer shroud portions, a movable end stop that guides along both slots, and a frangible stem to ensure controlled collapse, allowing for greater reach adjustment and enhanced structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single slot is provided in one shroud portion with a fixed end stop, then the structure is simpler, but the reach adjustment range is limited and the terminal ends have reduced structural strength
Solution Approach 1:
The single slot system is segmented into two separate slots - one in the inner shroud portion and one in the outer shroud portion. The end stop is also segmented into two separate end stops, each engaged with its respective slot. This segmentation allows each slot to be shorter while maintaining the overall adjustment range, and crucially allows the slots to be positioned away from the terminal ends, preserving structural strength at the ends.
Solution Approach 2:
The end stop acts as an intermediary element that mediates between the two slots. It moves along both slots simultaneously, with each end stop engaging its respective slot. This intermediary mechanism coordinates the movement of the inner and outer shroud portions, enabling the telescopic adjustment function while distributing the structural load away from the terminal ends.
2Adaptability or versatility
If the slot extends close to the terminal end to maximize adjustment range, then the reach adjustment capability is improved, but the structural strength at the terminal end is reduced
Solution Approach 1:
By segmenting the slot system into two separate slots in the inner and outer shroud portions, the invention allows each slot to be positioned away from the terminal ends. The slots can extend axially along their respective shroud portions without reaching the terminal ends, thereby maintaining structural strength while still providing the necessary adjustment capability through the combined telescopic action of both shroud portions.
3Strength
If the shroud is designed as a single rigid structure, then the structural strength is maximized, but the controlled collapse mechanism during crash is eliminated
Solution Approach 1:
The shroud is segmented into two separate shroud portions (inner and outer) that can move relative to each other telescopically. This segmentation creates a controlled weakness at the interface between the two portions, allowing the shroud to collapse in a controlled manner during a crash by telescoping, while maintaining overall structural strength through the design of the bearing assemblies and connection mechanisms.
Solution Approach 2:
The telescopic design with bearing assemblies provides beforehand cushioning by allowing controlled collapse during crash. The bearing assemblies are designed to accommodate the telescopic movement, creating a energy-absorbing mechanism that cushions the impact force before it reaches the driver, while maintaining normal structural strength during regular operation.
Data Source
AI summary
A steering column assembly is provided that is reach-adjustable. An inner shroud portion and outer shroud portion, which move telescopically relative to one another, each have an elongate slot, the slots at least partially overlapping at all times over the range of adjustment. An end stop extends through, and is movable within, both slots such that it strikes one end of each stop when the steering column assembly is fully retracted and the other end of each slot when the steering column assembly is fully extended.